TECHNICAL FIELD

Embodiments herein relate in general to systems, apparatus and methods for thermal treatment of solid chemical compounds, commonly called calcination. In particular, embodiments herein relate to systems and methods for calcination of material comprising calcium carbonate, like for example lime mud in a lime recovery cycle in cellulose industry or other industry.

Thus, embodiments herein relate to calcination system configurations, calcination methods and control methods for an electrically heated calcination system, for example with an electric gas plasma generator and more particularly for calcination of material comprising calcium carbonate, like for example lime mud, a media separated heat exchanger for energy efficient heating of solid chemical compounds, such as material comprising calcium carbonate, material comprising calcium carbonate, like for example lime mud, a heat pump arrangement for recovering heat from heated calcination process products, such as compounds or gas or a mixture thereof, particularly solids comprising calcium oxide, for example quick lime and/or gas comprising carbon dioxide CO2, output from a calcination reactor, a particle separator for use in a calcination system, the particle separator being configured to separate smaller particles from larger particles in a fluid bed of particles mixed with gas; and/or an injection arrangement for injection of heated solid chemical compound into the calcination reactor, particularly a chemical compound in the form of material comprising calcium carbonate, like for example lime mud.

In further variations, these embodiments may be applied in calcination of input material comprising carbonate to produce calcination process products comprising oxide and/or carbon dioxide.

BACKGROUND

In the general pursuit of adapting manufacturing and process industry to be more environmentally friendly and to decrease impact on climate change there is a need for increasing capacity and efficiency in calcination process solutions, for example for recovery of lime in paper manufacturing, cement industry or metal industry or other industrial calcination processes in various fields and industries. In conventional industrial processes calcination is carried out in furnaces or kilns usually heated by combustion or burning of fossil fuels or biofuels to achieve thermal decomposition of input material. This conventional kind of calcination is environmentally unfriendly and has undesired impacts on climate change. Other drawbacks are for example that the equipment is bulky, the process time is long, the process is difficult to control and investment costs for installation is high.

In recent development calcination is employed by means of electrically generated gas plasma in a plasma reactor. In a plasma heated calcination system, input material is exposed to heat radiation from a plasma flame incurring a temperature in parts of the calcination reactor in the range of 3000-4000 degrees Celsius. The higher temperatures that the input material, such as lime mud, is exposed to results in a faster calcination and throughput of material in the calcination process.

It has been proposed in patent publications WO 02/096820 and WO 02/096820 to employ calcination by means of electrically generated gas plasma. Compared to calcination with traditional furnaces or kilns, calcination in a calcination reactor heated by electrically generated gas plasma offers inter alia the following advantages. Capacity can be increased in for example by full scale deployment or in existing calcination facilities by deployment of supplementary smaller modules of electrical gas plasma calcinatory systems. Separation of gas comprising carbon dioxide CO2 can be conducted with a high degree of purity at low cost, heat can be recovered to a higher degree and installation costs are lower. Further advantages include higher energy efficiency, low degree of emission, rapid process control and possibilities to make the whole lime recovery cycle more efficient.

Irrespective of what type of calcination reactor and equipment that may be used, the process is complicated and adequate control of the whole calcination process is needed in order to provide energy efficient and safe installations. While throughput of material and efficiency is highly increased in a plasma heated calcination system compared to a conventional furnace or kiln based calcination system, it is still desirable to increase the yield and the utilization of the generated heat. OBJECT

It is a general object of the present invention to provide improved calcination system configurations, calcination methods and control methods for heated calcination, for example electrically heated calcination, and/or plasma heated calcination. More particular objects concern improved heat management in the calcination process as well as improved material and media flow in the calcination process. Embodiments herein relates to arrangements, systems and methods for calcination. Embodiments will be described in detail in the detailed description.

BRIEF DESCRIPTION OF DRAWINGS

Embodiments described herein will be further explained with reference to the accompanying drawings, wherein:

FIG 1 shows a schematic overview of a calcination system in accordance with exemplifying embodiments.

FIG 2 show embodiments of a calcination system with exemplifying embodiments of injection arrangements.

FIG 3 show embodiments of a calcination system with exemplifying embodiments of media separated heat exchanger.

FIG 4 shows show embodiments of a calcination system with exemplifying embodiments of a heat recovery arrangement.

FIG 5 shows show an embodiments of a particle separator.

FIG 6 shows show further embodiments of parts of a calcination system.

DETAILED DESCRIPTION

FIG 1 shows a schematic overview of embodiments of a calcination system configured for carrying out embodiments of calcination methods, here exemplified by an adaptation to calcination of material comprising calcium carbonate, like for example lime mud, for example applicable in a lime recovery cycle in cellulose industry. However, embodiments herein are generally useable and/or configurable for calcination or other thermal treatment of other input materials. In more general embodiments the input material comprises carbonate and calcination process products comprise an oxide and/or carbon dioxide. For example, carbonates may be in the form of or present in input materials such as lithium minerals, pottassium (K kalium) carbonate, magnesium carbonate or other carbonates. For example, solid calcination process products may be in the form of or comprising oxides such as lithium oxide or other oxides. For example, gas calcination process products may be in the form of or comprising carbon dioxide, monoxide or other gas.

In FIG 1 , system components comprised or optionally comprised in embodiments are schematically shown with arrows indicating flow channels for communicating or transporting material such as solid compounds and/or gas and/or heat between said components. Details drawn with intermittent lines indicate optional features in addition to the configuration of main embodiments in fully drawn lines. FIG 1 also serves as a schematic flow chart for embodiments of calcination methods.

Calcination

Thermal treatment of a solid chemical compound is commonly called calcination. In such a process the compound is heated to a high temperature below the melting point of the solid chemical compound generally under restricted supply of ambient oxygen. The general purpose may be to achieve thermal decomposition and/or to remove impurities or volatile substances.

Calcination of material comprising calcium carbonate

Calcination of material comprising calcium carbonate like for example lime in accordance with embodiments disclosed herein, is for example applicable in lime recovery cycles in process industry such as in the cellulose industry, in the cement industry or in the metal industry. In such lime recovery cycles lime comprising crystal forms of calcium carbonate (CaC03) is thermally decomposed to calcium oxide (CaO), for example for example quick lime, and gas comprising carbon dioxide (CO2). The calcination reaction is CaCO3(s) — CaO(s) + 002(g), where (s) denotes solid compound and (g) denotes gas form compound. For example, in the cellulose industry material comprising calcium carbonate, like for example lime mud is a byproduct obtained in pulp mills as part of the process that turns wood into pulp for paper. In a pulp mill, wood chips are cooked with sodium hydroxide to extract the wood fiber used to make paper from the lignin that binds the wood together. During this process, sodium hydroxide is converted to sodium carbonate. Calcium oxide, also known as quicklime, is then added to convert the sodium carbonate back to sodium hydroxide in order to use it again. In the process, material comprising calcium carbonate in the form of material comprising calcium carbonate, like for example lime mud is obtained. Material comprising calcium carbonate, like for example lime mud is mainly calcium carbonate mixed with water forming a sludge. The material comprising calcium carbonate, like for example lime mud is then calcined to retrieve calcium oxide in a lime recovery cycle. Before calcination, the material comprising calcium carbonate, like for example lime mud is preferably dried to an extent suitable for handling in connection with and in the calcination process. For example, the input material such as lime or material comprising calcium carbonate, like for example lime mud may be pulverized into a powder in connection with the drying. Similar processes are as mentioned applicable in other industries.

Calcination of calcium carbonate begins to occur at about 900 degrees Celsius, and normally calcination takes place at temperatures in the range 900-1100 degrees Celsius, whereby calcium oxide and gas comprising carbon dioxide is formed. The calcination reaction is reversible, and in order to avoid reformulation of calcium carbonate in the presence of gas comprising carbon dioxide the temperature must be maintained above the calcination temperature. With temperature rising to about 1100 degrees Celsius and above the calcium oxide sinters. In the sintering process the calcium oxide is compacting in the phenomenon that calcium crystals are collapsed and forming a solid mass of material. The rate of the sintering process increases with higher temperature. Furthermore, water vapor (herein also called steam) may be used as a catalyst for sintering. On the other hand, in order to avoid sintering the process should be kept free from water vapor. In the calcination process, gas comprising carbon dioxide CO2 is released from the calcium carbonate and after sintering the calcium oxide is more stable. After such a calcination process of lime input material comprising calcium carbonates being converted into solids comprising calcium oxide, for example quick lime, the solids as quick lime is usually slaked with so called green liquor, containing a solution of sodium carbonate.

Input for material to be thermally treated by calcination As shown in FIG 1 , an embodiment of a calcination system 100 comprises an input 102 for material to be thermally treated, for example an input in the form of a storage container for material comprising calcium carbonate, like for example lime mud. Typically, input material such as dried material comprising calcium carbonate, like for example lime mud is accommodated in the input 102 and communicated via a valve (not shown in FIG 1) to a media separated heat exchanger 104. Thus, embodiments of the calcination system comprise an input 102 for receiving input material comprising calcium carbonate, for example in the form of material comprising calcium carbonate, like for example lime mud. Embodiments of calcination methods herein comprise receiving input material comprising calcium carbonate, like for example in the form of material comprising calcium carbonate, like for example lime mud. Embodiments for lime calcination may be configured for input material in the form of lime raw material, which herein is material comprising calcium carbonate containing minerals or substances such as limestone, lime sludge, dolomite, calcium containing sludge or other forms. The particle separator 110 may be used in any calcination system.

With reference to FIG 2, a calcination system 100 comprising an electrically heated calcination 108 reactor is provided. The electrically heated calcination reactor 108 is configured to convert input material into calcination process products comprising a solid compound in the form of calcium oxide and a gas in the form of carbon dioxide. The system 100 further comprises a particle separator 110 that is described in more detail in conjunction with FIG 5 and FIG 6. The particle separator 110 is arranged to receive input material in the form of particles of lime mud. In the example, the particles are supplied at the top of the particle separator 110. The supplied particles may be supplied mixed with gas, and they may be preheated before supplied to the particle separator 110. The particle separator 110 comprises a chamber 401 configured to hold a fluid bed 402 of particles mixed with gas, into which fluid bed 402 gas is flowing from underneath 403, thereby separating smaller particles from larger particles by lifting the smaller particles upwards in the flow of gas. The separated larger particles will due to gravity forces move downwards in the particle separator 110. The particle separator 110 is coupled to a transfer channel 404 arranged to provide the flow of the separated smaller particles mixed with gas to an injection arrangement injecting the provided input material into an electrically heated calcination reactor 108.

The fluid bed 402 is controlled by the gas provided from underneath 403. As shown in FIG 6, the gas is supplied via a valve and a flow control unit. A first pressure is measured above the trap door device by use of a first pressure sensor, and a second pressure is measured below the trap door device by use of a second pressure sensor. The difference of the first and second pressure is calculated and may be used to control the trap door device. The particle separator 110 is configured to separate larger and heavier lumps of preheated material, such as lime mud, from smaller and lighter particles of material. The particle separator 110 is arranged such that lumps of material by gravity falls into a lump collection container and such that smaller particles are lifted by a stream of pre-heated gas and input into the injector arrangement 106. The particle separator 110 is provided with a controllable supply of heated gas. The supply of heated gas may be controllable by one or more actuators, preferably coupled to a control unit 126. The particle separator 110 may be coupled to an injection arrangement 106 and configured to convey smaller particles in a gas flow to the injection arrangement 106 for injection into the electrically heated calcination reactor 108.

Methods herein may comprise receiving sensor signals, generating control signals, and communicating control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators, by use of a control unit 126 communicatively coupled to sensors, actuators and other control means. Methods herein may further comprise controlling one or more of heated gas in the particle separator, and gas supply into the particle separator to support the fluid bed. Controlling the gas supply into the particle separator to support the fluid bed may comprise measuring the supplied gas flow. Further, measuring of a first pressure above the trap door device and measuring a second pressure below the trap door device may be performed. The difference between the first and the second pressure is calculated, and, if the calculated difference is negative, the trap door is prevented from being opened. This is important since if the trap door would open in such a situation, the fluid bed may be sucked down into the container 200 by the underpressure disturbing the process or causing the process to stop. Methods herein comprises separating, in a particle separator 110 coupled to the injection arrangement 106, such that larger lumps and smaller particles of solid compound in input material are separated, and conveying the smaller particles in a gas flow to the injection arrangement 106 for injection into the electrically heated calcination reactor 108. The particle separator 110 may be configured or controlled such that particles of pre-heated input material with a size in the range of 1 to 1000 micrometers are input to the calcination reactor 108 via the injection arrangement 106. With powder form the contact surface of the input material will become very large, whereby the contact time with heat in the calcination reactor can be minimized.

Media separated heat exchanger

The purpose of the media separated heat exchanger 104 is to raise the temperature of the input material without recirculation of material, preferably by using heat from heated calcination process products obtained downstream in the calcination system. Embodiments of the calcination system 100 comprises a media separated heat exchanger 104 coupled to said input and configured to conduct input material in a plurality of channels, for example tubes. Embodiments of a calcination method comprises conducting said input material in a plurality of channels of a media separated heat exchanger 104.

Input material, such as material comprising calcium carbonate, like for example lime mud, passes through and is heated by the media separated heat exchanger 104, and is output to an injection arrangement 106 via an outlet (not shown) from the media separated heat exchanger 104. In a configuration of the calcination system applied for lime recovery, the input material comprising calcium carbonate, like for example material comprising calcium carbonate, like for example lime mud preferably and ideally holds a temperature in the range of 900 degrees Celsius when it leaves the media separated heat exchanger 104.

The media separated heat exchanger 104 optionally comprises an inlet for a driving gas supply 105 configured to enable feeding of a driving gas at a pressure in the range of 1 ata (atmospheric pressure above vacuum). The purpose of the driving gas is to drive the input material, in particular input material comprising a solid compound, to move through the media separated heat exchanger 104. In embodiments for example adapted to calcination of lime, the driving gas is gas comprising carbon dioxide CO2 or steam. The driving gas is in embodiments recycled gas comprising carbon dioxide CO2 recovered from the calcination process. In embodiments adapted for input material in the form of generally dry material comprising calcium carbonate, like for example lime mud, remaining moisture in the input material comprising calcium carbonate, like for example lime mud may transform into steam in the media separated heat exchanger, which steam serves as driving gas itself or in addition to further supplied driving gas.

In embodiments, a selection of one or more actuators, preferably coupled to a control unit 124, are configured for controlling one or more of feeding of input material, for example by means of the above mentioned valve (not shown in FIG 1 ) for communicating input material into the media separated heat exchanger 104, the distribution of input material into or within the media separated heat exchanger 104 by means of a distribution mechanism, the input of driving gas from the driving gas supply 105 for controlling the velocity of movement of input material transported through the media separated heat exchanger.

Input material, material comprising calcium carbonate, like for example material comprising calcium carbonate, like for example lime mud, is in embodiments conducted through a plurality of input material tubes (not shown in FIG 1 ) of the media separated heat exchanger 104. The input material tubes are configured in the media separated heat exchanger 104 such that a hot medium conducted through the media separated heat exchanger 104 transfers thermal energy by heat convection and heat radiation to input material passing through the input material tubes. In example embodiments, the media separated heat exchanger 104 is provided with a cavity surrounding the input material tubes and such that hot medium through the media separated heat exchanger comes into contact with said tubes.

Embodiments of the media separated heat exchanger 104 are shown in FIG 3. FIG. 3 shows a media separated heat exchanger 104 for use in a system 100 for calcination of material comprising calcium carbonate, like for example lime mud, or in any other system for heating of fine-grained solid material, in accordance with embodiments herein. The media separated heat exchanger 104 comprises an outer shell 302 and one or more tubes 304 arranged inside the shell 302. In embodiments, a media separated heat exchanger 104 for use in a system for calcination of material comprising calcium carbonate, like for example lime mud is provided. The media separated heat exchanger 104 is arranged to heat material comprising calcium carbonate, like for example material comprising calcium carbonate, like for example lime mud by heat transfer from hot gas mixed with calcium oxide. The media separated heat exchanger comprises an outer shell 302 and one or more tubes 304 arranged inside the shell 302. A a first medium for heat transfer is fed into the tubes 304 and flows during heat transfer. A second medium for heat transfer flows outside the tubes. The first medium may be hot gas mixed with calcium oxide and the second medium may be material comprising calcium carbonate, like for example lime mud. Alternatively, the first medium may be material comprising calcium carbonate, like for example lime mud and the second medium may be hot gas mixed with calcium oxide.

The media separated heat exchanger 104 may comprise an outer shell 302 and one or more tubes 304 arranged inside the shell 302. Input material comprising calcium carbonate, like for example material comprising calcium carbonate, like for example lime mud is fed into the tubes 304 for transport during heating. The media separated heat exchanger 104 further comprises one or more primary inlets 306 for feeding heated gas used for the heating of the material comprising calcium carbonate, like for example lime mud. The heated gas is received from a calcination reactor and/or a cyclone comprised in the system for calcination of material comprising calcium carbonate, like for example lime mud. The media separated heat exchanger further comprises an outlet 308 for feeding heated material comprising calcium carbonate, like for example lime mud into the reactor 108.

In embodiments, the media separated heat exchanger 104 further comprises a distributor 310 for feeding and distributing material comprising calcium carbonate, like for example lime mud into the one or more tubes 304. The distributor 310 may be vibrating, whereby the material comprising calcium carbonate, like for example lime mud is evenly spread into the tubes 304. The distributor 310 may further be arranged to separate large particles from small, whereby fine-grained particles are fed into the one or more tubes 304. The media separated heat exchanger 104 may further comprise one or more secondary inlets for feeding heated gas from an io external supply into the exchanger. Thereby, the flow of heated gas and the temperature in the heat exchanger may be controlled in a more accurate way.

The one or more tubes 304 may be provided with one or more moveable chains arranged on the inside of the tubes 304. Thereby a turbulent flow of the fed material comprising calcium carbonate, like for example lime mud is achieved. The chains may alternatively be arranged on the outside of the tubes 304 whereby a turbulent flow will be present outside the tubes. As further alternatives, wires or the like may be used, and such wires may be arranged on the inside or the outside of the tubes. The inner side of the shell 302 may be provided with irregularities in the surface, whereby a turbulent flow of the media flowing outside the tubes is provided. The media flowing outside may be material comprising calcium carbonate, or may be heated gas. Turbulent flow is advantageous compared to laminar flow since the exchange of heat will be improved since the path for the material comprising calcium carbonate, like for example lime mud to pass through the tubes 304 will be longer, and the resulting contact area for the different media to exchange heat with each other will be larger. For example, there may be more frequent particle-to-particle contacts, particle-to-heat exchanger wall contacts and the like.

The heat exchanger works as follows. Dried material comprising calcium carbonate, like for example lime mud, or any other solid material, in the form of small particles is fed into the tubes 304 which serves for transport of the material comprising calcium carbonate, like for example lime mud during heating. As can be seen from the figure, the material comprising calcium carbonate, like for example lime mud may be fed into the tubes via a distributor for feeding and distributing material comprising calcium carbonate, like for example lime mud into the tubes at the upper ends. The distributor may be arranged to move for example in an oscillating movement or may be arranged to move back and forth in order to distribute the material comprising calcium carbonate, like for example lime mud evenly in the tubes. The distributor may further be provided with a separator configured to separate larger particles of the material comprising calcium carbonate, like for example lime mud from smaller. The more even sized particles and the more even fed into the tubes, the better performance of the media separated heat exchanger 104. The material comprising calcium carbonate, like for example lime mud is then moving inside the tubes towards the lower end and at the same time the tubes and thus the material comprising calcium carbonate, like for example lime mud is heated. To achieve as efficient heat transfer as possible, the material comprising calcium carbonate, like for example lime mud may move along the inside of the tubes in a turbulent flow. This may be achieved by a configuration wherein the tubes are provided with a chain, or a wire or the like, on the inside or on the outside of the tubes whereby a turbulent flow of said fed material comprising calcium carbonate, like for example lime mud is achieved.

The media separated heat exchanger 104 is further provided with one or more primary inlets for feeding heated gas used when heating the material comprising calcium carbonate, like for example lime mud in the tubes. The heated gas is received from a calcination reactor and/or a cyclone comprised in the system for calcination of material comprising calcium carbonate, like for example lime mud. The primary inlet, or inlets, is provided in the lower part of the shell of the media separated heat exchanger 104. The heated gas, which may have a content of pulverized solid material, is led into the shell via the primary inlet, or inlets, and then moves upwards inside the heat exchanger. Heat will be transferred from the heated gas via the tubes to the material comprising calcium carbonate, like for example lime mud. To achieve as effective heat transfer as possible and to prevent fouling on inner surfaces or even clogging of the flow paths, also the heated gas may move in a turbulent flow inside the shell of the heat exchanger, in embodiments with turbulators such as chains, wires or other movable structures in the spaces outside the tubes.

It is to be noted that in the heat exchanger 104, the material comprising calcium carbonate, like for example lime mud may flow in the tubes and the hot gas may flow outside the tubes. Alternatively, the hot gas may flow in the tubes, and the material comprising calcium carbonate, like for example lime mud may flow outside the tubes. This will be explained more in detail later. The calcination reactor is in the exemplifying figures shown as a plasma reactor, but the media separated heat exchanger may be used together with any type of calcination reactor.

Injection arrangement Embodiments of the injection arrangement 106 are shown in FIG 2. The injection arrangement 106 is configured to convey and inject the input material, for example heated material comprising calcium carbonate, like for example lime mud, into an electrically heated calcination reactor 108. The injection arrangement may in exemplified embodiments be coupled to a particle separator 110. Embodiments of the calcination system 100 comprises an injection arrangement 106 configured to receive input material from the media separated heat exchanger 104 and to inject input material into an electrically heated calcination reactor 108. Embodiments of a calcination method comprises injecting input material into an electrically heated calcination reactor 108.

Embodiments of the injection arrangement 106 comprises an inlet for an injection gas supply 107 configured to enable feeding of an injection gas at a controllable pressure, for example in the range of 1-5 ata (atmospheric pressure above vacuum). The purpose of the injection gas is to control the injection rate, the injection pressure, the distribution and/or the temperature of the pre-heated input material injected into the electrically heated calcination reactor 108. In embodiments, the inlet for injection gas supply is controllable by one or more actuators, preferably coupled to control unit126. In embodiments for example adapted to calcination of lime, the injection gas is gas comprising carbon dioxide CO2 or steam. The injection gas is in embodiments recycled gas comprising carbon dioxide CO2 recovered from the calcination process.

Embodiments of an injection arrangement 106 in a calcination system 100 comprises an injector inlet 202 configured to receive preheated input material, for example material comprising calcium carbonate, like for example lime mud, from a media separated heat exchanger 104 into a fluid conductor configured for transferring said preheated input material to an injector 208; said injector 208 being configured to inject said preheated material into an electrically heated calcination reactor 108; and an injection gas 107 supply configured to supply gas for transfer and injection of input material into said electrically heated calcination reactor 108. In embodiments of the injection arrangement 106 the injection gas 107 is preheated in an injection gas tube 210 conducted through the media separated heat exchanger 104. In embodiments combined with a particle separator the injection arrangement 106 is configured such that said inlet 202 is positioned in a cavity configured to communicate preheated input material from said media separated heat exchanger 104 to a particle separator 110 and is configured to receive a rising flow of preheated input material in a stream of injection gas 107. The injection gas 107 is in such embodiments supplied in a flow such that smaller particles are lifted by the injection gas stream. This kind of configuration is suitable in embodiments wherein the injector 208 is configured to inject said preheated input material into a forma 214 of an electric plasma generator 213 of said electrically heated calcination reactor 108.

In other embodiments of the injection arrangement 106, the injector 208 is configured to inject the preheated input material into a calcination chamber 216 of the electrically heated calcination reactor 108 in an input material stream tangential in relation to a gas plasma stream generated by an electric plasma generator 213 of said electrically heated calcination reactor 108. In embodiments of the injection arrangement 106 the injector inlet 202 and an outlet 218 for said injection gas supply is positioned at an outlet 220 of said media separated heat exchanger 104.

Particle separator

The particle separator 110, also shown for example in Figs 5 and 6, is, in embodiments where it is comprised, configured to separate larger and heavier lumps of preheated material, such as material comprising calcium carbonate, like for example lime mud, from smaller and lighter particles of material. The particle separator 110 is in embodiments devised such that lumps of material by gravity falls into a lump collection container and such that smaller particles are lifted by a stream of pre-heated gas and input into the injector arrangement 106. Embodiments of the particle separator is provided with a controllable supply of heated gas. In embodiments the supply of heated gas is controllable by one or more actuators, preferably coupled to control unit 124. In embodiments, the gas pressure in the particle separator is controlled by controlling the driving gas supply 105 on the cold side of the media separated heat exchanger 104.

Embodiments of the calcination system 100 comprises a particle separator 110 coupled to the injection arrangement 106 and configured to separate larger lumps and smaller particles of solid compound in input material, and to convey said smaller particles in a gas flow to said injection arrangement 106 for injection into said electrically heated calcination reactor 108. Embodiments of the calcination method comprises separating, in a particle separator 110 coupled to the injection arrangement 106, such that larger lumps and smaller particles of solid compound in input material are separated, and conveying said smaller particles in a gas flow to said injection arrangement 106 for injection into said electrically heated calcination reactor 108.

The particle separator may be configured or controlled such that particles of preheated input material with a size in the range of 1 to 1000 micrometers are input to the calcination reactor 108 via the injection arrangement 106. With powder form the contact surface of the input material will become very large, whereby the contact time with heat in the calcination reactor can be minimized.

Electrically heated calcination reactor

The electrically heated calcination reactor 108 is thus configured to receive a flow of pre-heated material, such as material comprising calcium carbonate, like for example lime mud, from the injector arrangement and expose the material to heat generated by electricity. Embodiments of the calcination system comprises a said electrically heated calcination reactor 108 being configured to convert input material received by means of said injection arrangement 106 into calcination process products comprising a solid compound, for example comprising calcium oxide, and a gas, for example in the form of gas comprising carbon dioxide. Embodiments of a calcination method comprise converting, in said electrically heated calcination reactor 108, input material into calcination process products comprising a solid compound, for example comprising calcium oxide, and a gas, for example in the form of gas comprising carbon dioxide.

In embodiments, the calcination reactor is electrically heated by an electric gas plasma generator configured to inject hot gas plasma, such as gas comprising carbon dioxide plasma, into a calcination chamber of the calcination reactor 108, and possibly maintain production of gas plasma in the calcination chamber from gas, such as gas comprising carbon dioxide CO2, formed in the calcination process. In embodiments applied for heat treatment of material comprising calcium carbonate, like for example lime mud, the material comprising calcium carbonate, like for example lime mud that is exposed to the heat of the gas plasma is converted to calcination process products comprising calcium oxide, for example quick lime, and gas comprising carbon dioxide CO2. The calcination reactor 108 is further configured to exit the heat-treated material and if applicable the calcination process products, such as for example quick lime and gas comprising carbon dioxide carbon dioxide, to a first (1st) separator 112.

An electric gas plasma generator (not shown in FIG 1 ), comprised in embodiments of the calcination reactor, is devised to supply energy via an electric arc formed between electrodes. Gas is ionized and an energetic gas plasma is formed. Such gas plasma normally has a temperature in the range of 3000-4000 degrees Celsius or more at the discharge of the gas plasma generator. The gas plasma generator comprises a nozzle called forma configured to inject gas plasma into the calcination reactor 108. Pressurized gas may be supplied to the forma to overcome a pressure drop occurring over the gas plasma generator. The pressurized gas may be used to control the temperature of the gas plasma.

Preheated input material is in the calcination reactor mixed with or exposed to hot gas from the plasma generator. The calcination reactor is in embodiments configured to balance the exposure of the pre-heated input material to heat at too high temperature. For example, for input material comprising lime with calcium carbonate exposure to calcination temperatures exceeding 1200 degrees Celsius may entail risk for inactivating the lime, also called dead burning of the lime. Configuring the calcination reactor such that the input material when injected in the calcination reactor is in powder form thus having a large surface and such that the powder formed input material is exposed to heat for a limited period of time enables that inactivation of the input lime is avoided.

Generally, the input material is calcinated during fragments of seconds to a few seconds. Calcination is preferably carried out at atmospheric pressure, or at a small over-pressure or under-pressure.

In other embodiments, the calcination reactor 108 may be electrically heated using resistive technology, microwave or radio wave technology, or other electrically driven heating.

First separator The first (1st) separator 112 is configured to separate resulting process products generated by the heat treatment of the material in the calcination reactor 108, such as solid calcination process products comprising calcium oxide (such as for example quick lime) and gas formed calcination process products in the form of gas comprising carbon dioxide CO2 when applied in a lime recovery cycle. The temperature of the calcination process products received from the calcination reactor 108 is in lime calcination embodiments exceeding 900 degrees Celsius.

In the separator 112, larger and/or heavier particles in the material flow input from the calcination reactor 108 are separated from smaller and/or lighter particles and gas. The larger and/or heavier particles are collected in a collection hopper (not shown in FIG 1 ), and residual calcination process products in the form of gas usually together with a certain amount of smaller and/or lighter particles are conducted out from the first separator 112 to a first (1st) heat recovery arrangement 116. In embodiments the first separator 112 is a cyclone, an electric filter or a sedimentation device or sedimentation arrangement.

Embodiments of the calcination system 100 may comprise one or more separators 112,118 configured to separate said solid compound comprising calcium oxide and gas in the form of gas comprising carbon dioxide of said calcination process products. Embodiments of a calcination method comprises separating, in one or more separators 112, 118 said solid compound, for example comprising calcium oxide and gas, for example in the form of gas comprising carbon dioxide of said calcination process products.

Embodiments of the calcination system 100 may comprise a first separator 112 configured to receive calcination process products from the electrically heated calcination reactor 108 and to separate solid compound, for example comprising calcium oxide, from the gas, for example in the form of gas comprising carbon dioxide, of the calcination process products. Embodiments of the calcination method, comprise separating, in a first separator 112, calcination process products received from the electrically heated calcination reactor (108) such that solid compound, for example comprising calcium oxide, is separated from the gas, for example in the form of gas comprising carbon dioxide, of the calcination process products. In embodiments applied for recovery from a material comprising calcium carbonate, like for example lime mud, the residual calcination process products output from the first separator 112 will comprise and usually mainly consist of gas comprising carbon dioxide CO2 and fine-grained residual comprising calcium oxide (for example quick lime). In embodiments of such lime recovery, a separation ratio in a cyclone variant of the first separator 112 would for example be in the range of 75 % of the material comprising calcium oxide (for example quick lime) input from the calcination reactor 108 being collected in the collection hopper and in the range of 25 % of the material comprising calcium oxide (for example quick lime) being output from the separator 112 together with gas comprising carbon dioxide CO2.

First heat recovery arrangement

The first (1st) heat recovery arrangement 116 is configured to recover heat from the residual calcination process products output from the first separator 112. Embodiments of the calcination system comprises a first heat recovery arrangement 116 configured to receive said calcination process products, to extract heat from said calcination process products and transfer said extracted heat to said input material in said media separated heat exchanger 104. Embodiments of a calcination method comprise extracting, in a first recovery arrangement 116, heat from said calcination process products and transferring said extracted heat to said input material in said media separated heat exchanger 104.

In embodiments the first (1st) heat recovery arrangement 116 comprises a flow line configured to conduct a flow of residual calcination process products at a first higher temperature into the media separated heat exchanger 104, through said media separated heat exchanger 104 where residual calcination process products transfer heat to input material moving through said media separated heat exchanger 104 and out of said media separated heat exchanger 104 at a second lower temperature. In embodiments the (1st) heat recovery arrangement 116 alternatively or additionally comprises a heat pump (not shown in FIG 1 ) configured to extract heat from the residual calcination process products and preferably to transfer said extracted heat to the media separated heat exchanger.

General embodiments of calcination systems and calcination methods Embodiments of a calcination system 100, comprises: an input 102 for receiving input material, for example in the form of material comprising calcium carbonate, like for example lime mud; a media separated heat exchanger 104 coupled to said input and configured to conduct input material in a plurality of channels; an injection arrangement 106 configured to receive input material from the media separated heat exchanger 104 and to inject input material into an electrically heated calcination reactor 108; a said electrically heated calcination reactor 108 being configured to convert input material received by means of said injection arrangement 106 into calcination process products comprising a solid compound comprising calcium oxide and a gas in the form of gas comprising carbon dioxide; a first heat recovery arrangement 116 configured to receive said calcination process products, to extract heat from said calcination process products and transfer said extracted heat to said input material in said media separated heat exchanger 104; and one or more separators 112, 118 configured to separate said solid compound comprising calcium oxide and gas in the form of gas comprising carbon dioxide of said calcination process products.

Embodiments of a calcination methods may comprise receiving input material, for example in the form of material comprising calcium carbonate, like for example lime mud; conducting said input material in a plurality of channels of a media separated heat exchanger 104; injecting input material into an electrically heated calcination reactor 108; converting, in said electrically heated calcination reactor 108, input material into calcination process products comprising a solid compound comprising calcium oxide and a gas in the form of gas comprising carbon dioxide; extracting, in a first recovery arrangement 116, heat from said calcination process products and transferring said extracted heat to said input material in said media separated heat exchanger 104; and separating, in one or more separators 112, 118, said solid compound comprising calcium oxide and gas in the form of gas comprising carbon dioxide of said calcination process products.

Second heat recovery arrangement

Embodiments of a second (2nd) heat recovery arrangement 114 are shown in FIG 4. A second (2nd) heat recovery arrangement 114, comprised in certain embodiments, is arranged to extract heat from the first separator 112. Such extracted heat is carried in a gas, and the thus heated gas may be used as input into the injection arrangement 106. The second (2nd) heat recovery arrangement 114, the flow of extracted heat and the flow lines for the heated gas are in the figures drawn with intermittent lines as to indicate optional features.

In embodiments the heated gas from the second heat recovery arrangement 114 may be used as input to the injection arrangement 106 and/or into the calcination reactor 108. In embodiments of a calcination reactor with an electric gas plasma generator the heated gas may be used as input in or at the forma where it on one hand cools the gas plasma, and on the other hand also contributes with useful heat energy. In embodiments, the second heat recovery arrangement 114 may be controllable by one or more actuators, preferably coupled to the control unit 124, with regard to one or more parameters such as flow, amount of energy, temperatures and pressure.

Embodiments of the calcination system 100 may comprise a second heat recovery arrangement 114 configured to extract heat from solid compound, for example comprising calcium oxide, of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas, for example in the form of gas comprising carbon dioxide, of the calcination process products, said extracted heat being carried by a gas and inserted into the injection arrangement 106. Embodiments of the calcination method comprise extracting, in a second heat recovery arrangement 114, heat from solid compound, for example comprising calcium oxide, of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas, for example in the form of gas comprising carbon dioxide, of the calcination process products, carrying said extracted heat by a gas and inserting said heat carrying gas into the injection arrangement 106.

FIG 4 shows a heat recovery arrangement for reuse of heat in a calcination system, here exemplified in a system for calcination of material comprising calcium carbonate, like for example lime mud. The heat recovery arrangement comprises an expander for expanding and cooling incoming gas and a heat exchange tube arranged in a collection hopper for gathering heat treated solid material, such as calcium oxide extracted from a system configured for calcination of material comprising calcium carbonate, like for example lime mud. Expanded and thus thereby cooled gas is led into the tube and is heated by the solid compound, in this example calcium oxide for example quick lime. The heat recovery arrangement further comprises a compressor for compressing and heating the heated gas, and an inlet for reentering the compressed and heated gas into the system for calcination of material comprising calcium carbonate, like for example lime mud, whereby heat from the calcination process is reused.

Embodiments of the heat recovery arrangement 114 comprises an inlet 402 for receiving incoming gas from the system 100 for calcination of material comprising calcium carbonate, like for example lime mud. The incoming gas is preheated by excess heat generated by the system 100 for calcination of material comprising calcium carbonate, like for example lime mud. In a system 100 for calcination of material comprising calcium carbonate, like for example lime mud, a lot of heat is generated in different steps of the process. Therefore, heat for preheating the gas may be extracted from different parts of the system 100. The heat recovery arrangement 114 further comprises an expander 404 for expanding and cooling the incoming preheated gas, and a heat recovery tube 406 arranged in a container 408 comprising material comprising calcium oxide like for example quick lime extracted from the system (100) for calcination of material comprising calcium carbonate, like for example lime mud. It may be noted that the heat recovery tube 406 may be arranged in any container in the system 100 comprising heated material.

In embodiments, the expanded and cooled gas is led into the tube 410 and is heated by the heat from the material comprising calcium oxide like for example quick lime in the container. The heat recovery arrangement 114 further comprises a compressor 412 for compressing and further heating said heated gas and an outlet 414, for example comprising a diffusor for alleviating the downstream tubes from excessive pressure, from which the compressed and further heated gas is led out and reentered into the system 100 for calcination of material comprising calcium carbonate, like for example lime mud, whereby heat generated from the calcination process is reused. The compressed and further heated gas received from the heat recovery arrangement 114 may have a temperature of about 1000 - 1300 degrees Celcius, and may be reentered into different parts of the system 100, for example into the injection arrangement 106, or into the media separated heat exchanger 104, or directly into the calcination reactor 108.

Steam boiler

Referring to FIG 1 and FIG 4, a steam boiler 120, present in certain embodiments, is configured to extract remaining heat from the residual calcination process products received from the first heat recovery arrangement and before residual solid compounds is separated from gas in a subsequent second separator 118. In lime calcination embodiments the solid compound is calcium oxide and the gas is gas comprising carbon dioxide CO2. Steam generated in the steam boiler 120 is conducted from the steam boiler 120, for example for use to support processes in embodiments of the calcination system or for use in other processes in a facility employing embodiments of the calcination system. In embodiments, pressurized steam is generated producing process steam or power. Power may be produced in power generators for example in the form of a turbine. The temperature of the residual calcination process products entering the steam boiled is for example in lime calcination embodiments usually in the range of 400-500 degrees Celsius, whereas after having passed the steam boiler 120, the temperature of the residual calcination process products may be for example be in the range of 200 degrees Celsius.

Embodiments of the calcination system comprises a steam boiler 120 configured to extract heat from calcination process products from the preceding heat recovery arrangement and to generate steam. Embodiments of the calcination method comprise extracting, in a steam boiler 120, heat from gas of calcination process products from the one or more separators and generating steam.

Second separator

The residual calcination process products having passed the 1 st heat recovery arrangement 116 is conducted to a second (2nd) separator 118 configured to separate residual calcination process products. For example, remaining solid compounds is separated from gas. In embodiments the second (2nd) separator 118 is a cyclone. In embodiments of the calcination system configured for lime recovery from material comprising calcium carbonate, like for example lime mud, residual calcium oxide is further separated from gas comprising carbon dioxide CO2. Solid compounds, such as calcium oxide in lime calcination embodiments, is collected in a collection hopper and the further cleaned gas, such as gas comprising carbon dioxide CO2, is conducted to a filter arrangement 122 via an optional steam boiler 120.

Embodiments of the calcination system 100 comprises: a second separator 118 configured to receive residual calcination process products output from the first separator 112 and from the first heat recovery system 116, said second separator 118 being configured to further separate solid compound, for example comprising calcium oxide, from the gas, for example in the form of gas comprising carbon dioxide, of said residual calcination process products. Embodiments of the calcination method comprise separating, in a second separator 118, residual calcination process products received from the first separator 112 and from the first heat recovery system 116, such that further solid compound, for example comprising calcium oxide, is separated from the gas, for example in the form of gas comprising carbon dioxide, of said residual calcination process products.

Filter arrangement

The filter arrangement 122 is configured to filter the gas component of the calcination process products to a higher degree of purity before collecting, storing and/or using the output gas. In lime calcination embodiments the gas component of the calcination process products is gas comprising carbon dioxide CO2. In such embodiments, the filter arrangement 122 would comprise a filter adapted to filter gas comprising carbon dioxide CO2. The filtered gas component of the calcination process products is conducted to a gas output 124. When the temperature of the gas has been decreased to a low temperature of around for example 200 degrees Celsius, textile filters may be applied.

The filter arrangement 122 is in embodiments configured to filter out possible dust and such impurities still present in the gas output from the second separator 118. The filter arrangement is selected to fit to the temperature levels of the gas from said second separator 118. Embodiments of the calcination system comprises a filter arrangement 122 configured to receive gas of calcination process products, for example in the form of gas comprising carbon dioxide, from the one or more separators and to filter said gas to a higher degree of purity. Embodiments of the calcination method comprises filtering, in a filter arrangement 122 gas of calcination process products, for example in the form of gas comprising carbon dioxide, received from the one or more separators, such that said gas is filtered to a higher degree of purity.

Gas output

The gas output 123 is configured to receive the gas component of the calcination process products, and is in different embodiments configured to store, temporarily or for a longer term, or conduct the gas to the calcination system itself or to other systems and/or processes. In lime calcination embodiments the gas conducted to the gas output 124 would be gas comprising carbon dioxide CO2, and would in embodiments be recirculated to the calcination reactor.

Control unit

A control unit 126, comprised in embodiments, is configured to receive sensor signals, to generate control signals and to communicate control signals through a control port 128 connected to one or more signal lines 130. The one or more signal lines is schematically indicated as an intermittent line that is connected to sensors and/or control actuators (not shown) at different points and components of the calcination system in order to control various parameters. Embodiments of the calcination system 100 comprising a control unit 126 communicatively coupled to sensors and control actuators and configured to receive sensor signals, to generate control signals and to communicate control signals through a control port 128 connected to one or more signal lines 130 coupled to said sensors and control actuators. Embodiments of the calcination method comprises in a control unit 126 communicatively coupled to sensors and control actuators, receiving sensor signals, generating control signals and communicating control signals through a control port 128 connected to one or more signal lines 130 coupled to said sensors and control actuators. In embodiments of the calcination system 100, the control unit is configured to control one or more of: driving gas supply 105 into the media separated heat exchanger 104; injection gas supply 107 into the injection arrangement 106; heated gas in the particle separator 110; gas pressure in the calcination chamber 108; and/or temperature in the calcination chamber 108. Embodiments of the calcination method, further comprises controlling one or more of: driving gas supply 105 into the media separated heat exchanger 104; injection gas supply (107) into the injection arrangement 106; heated gas in the particle separator 110; gas pressure in the calcination chamber 108; and/or temperature in the calcination chamber 108.

The heat recovery arrangement 114 comprises an inlet 402 for receiving incoming gas from the system 100 for calcination of material comprising calcium carbonate, like for example lime mud. The incoming gas is preheated by excess heat generated by the system 100 for calcination of material comprising calcium carbonate, like for example lime mud. The heat recovery arrangement 114 may further comprise an expander 404 for expanding and cooling the incoming preheated gas and a heat recovery tube 406 arranged in a container 408 comprising material comprising calcium oxide like for example quick lime extracted from the system 100 for calcination of material comprising calcium carbonate, like for example lime mud. The expanded and cooled gas is led into the recovery tube 410 and is heated by the heat from the material comprising calcium oxide like for example quick lime. The heat recovery arrangement 114 may further comprise a compressor 412 for compressing and further heating the preheated gas and an outlet 414 from which the compressed and further heated gas is led out and reentered into the system 100 for calcination of material comprising calcium carbonate, like for example lime mud. Thereby heat generated from the calcination process is reused.

The incoming gas may be gas comprising carbon dioxide CO2 with a temperature of approximately 200 degrees and a pressure of approximately 4 bar (a). The outcoming gas may have a temperature of approximately 1000 - 1300 degrees and a pressure of approximately 2 bar (a). The heat recovery arrangement 114 may comprise a diffuser 418 arranged to diffuse the outcoming gas from the outlet 414. Thanks to the diffuser, the gas is presented with a lower pressure but high temperature which provides for a more safe solution. The compressor 412 may be arranged inside a housing 420. The housing 420 protects adjacent equipment from dangerous hot gas with high pressure.

Further aspects and embodiments

?5 Further aspects and still further embodiments herein will now be described with reference to the accompanying drawings.

Further embodiments of injection arrangement and method

In embodiments, an injection arrangement 106 in a calcination system 100 is provided. The injection arrangement 106 comprises an injector inlet 202 configured to receive preheated input material comprising calcium carbonate, for example in the form of lime mud, from a media separated heat exchanger 104 into a fluid conductor configured for transferring the preheated input material to an injector 208. The injector 208 is configured to inject the preheated material into an electrically heated calcination reactor 108. An injection gas 107 supply is configured to supply gas for transfer and injection of input material into the electrically heated calcination reactor 108.

In embodiments, the injection gas 107 may be preheated in an injection gas tube 210 conducted through the media separated heat exchanger 104. The inlet 202 may be positioned in a cavity configured to communicate preheated input material from the media separated heat exchanger 104 to a particle separator 110 and may be configured to receive a rising flow of preheated input material in a stream of injection gas 107. The injection gas 107 may be supplied in a flow such that smaller particles may be lifted by the injection gas stream. The injector 208 may be configured to inject the preheated input material into a forma 214 of an electric plasma generator 213 of the electrically heated calcination reactor 108. The injector 208 may be configured to inject the preheated input material into a calcination chamber 216 of the electrically heated calcination reactor 108 in an input material stream directed tangential in relation to a rotational symmetric cross section of the calcination chamber 216 of the electrically heated calcination reactor 108. The injector inlet 202 and an outlet 218 for the injection gas supply may be positioned at an outlet 220 of the media separated heat exchanger 104.

According to other aspects, an injection method in a calcination system is provided. The method comprises receiving, in an injector inlet 202, preheated input material comprising calcium carbonate, for example in the form of lime mud, from a media separated heat exchanger 104, transferring, in a fluid conductor, the preheated input material to an injector 208, injecting, through a the injector 208, the preheated material into an electrically heated calcination reactor 108, and supplying, an injection gas 107, for transfer and injection of input material into the electrically heated calcination reactor 108.

In other embodiments, injection methods herein may further comprise preheating the injection gas 107 in an injection gas tube 210 conducted through the media separated heat exchanger 104. In other embodiments, injection methods herein may further comprise communicating, via the inlet 202, preheated input material from the media separated heat exchanger 104 to the particle separator 110, and receiving a rising flow of preheated input material in a stream of injection gas 107. The injection gas 107 may be supplied in a flow such that smaller particles may be lifted by the injection gas stream. In other embodiments, injection methods herein may further comprise injecting the preheated input material into a forma 214 of an electric plasma generator 213 of the electrically heated calcination reactor 108.

In other embodiments, injection methods herein may further comprise injecting the preheated input material into a calcination chamber 216 of the electrically heated calcination reactor 108 in an input material stream directed tangentially in relation to a rotational symmetric cross section of the calcination chamber 216 of the electrically heated calcination reactor 108. The injector inlet 202 and an outlet 218 for the injection gas supply may be positioned at an outlet 220 of the media separated heat exchanger 104. In other embodiments, injection methods herein may further comprise holding a fluid bed 402 of particles mixed with gas in a chamber 401 of a particle separator, into which fluid bed 402 gas may be flowing from underneath 403, thereby separating smaller particles from larger particles by lifting the smaller particles upwards in the flow of gas, transferring from the fluid bed 402, a flow of the separated smaller particles mixed with gas to an injection arrangement 106 via a transfer channel 404, and thereby injecting the provided input material into the electrically heated calcination reactor 108.

In other embodiments, injection methods herein may further comprise that the particle separator is communicating with a control unit 126 that may be communicatively coupled to sensors and control actuators, the control unit 126 is receiving sensor signals, generating control signals and communicating control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators. In other embodiments, injection methods herein may further comprise the control unit controlling one or more of heated gas flow from above into the particle separator 110, and gas flow from underneath 403 into the fluid bed 402. In other embodiments, injection methods herein may further comprise separating the fluid bed 402 from a container 200 of the particle separator 110 by a trap door device 203, and collecting, in the container, larger particles separated from the fluid bed 402. In other embodiments, injection methods herein may further comprise regulating the gas flow from underneath 403 to the fluid bed 402. In other embodiments, injection methods herein the injection method may further comprise regulating the flow of gas through the valve. Measuring a first pressure above the trap door device, and measuring a second pressure below the trap door device 203 may be performed. The difference between the first and the second pressure is calculated, and if the calculated difference is negative, the trap door device is prevented from opening. In other embodiments, injection methods herein may comprise, in a calcination system 100, receiving input material comprising calcium carbonate, for example in the form of lime mud, separating smaller particles from larger particles of input material in a fluid bed by lifting the smaller particles upwards in a flow of gas, providing the flow of the separated smaller particles mixed with gas to an injection arrangement 106, injecting the separated input material into an electrically heated calcination reactor 108 by use of the injection arrangement 106, converting, in the electrically heated calcination reactor 108, input material into calcination process products comprising a solid compound comprising calcium oxide and a gas comprising carbon dioxide, extracting, in a first heat recovery arrangement 116, heat from the calcination process products and transferring the extracted heat to the input material in the media separated heat exchanger 104, and separating, in one or more separators 112, 118, the solid compound comprising calcium oxide and gas comprising carbon dioxide of the calcination process products.

In other embodiments, injection methods herein may further comprise extracting, in a second heat recovery arrangement 114, heat from solid compound comprising calcium oxide of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas comprising carbon dioxide of the calcination process products, carrying the extracted heat by a gas and inserting the heat carrying gas into the injection arrangement 106. In other embodiments, injection

?8 methods herein may further comprise separating, in a first separator 112, calcination process products received from the electrically heated calcination reactor 108 such that solid compound comprising calcium oxide may be separated from the gas comprising carbon dioxide of the calcination process products. The injection method may further comprise separating, in a second separator 118, residual calcination process products received from the first separator 112 and from the first heat recovery system 116, such that further solid compound comprising calcium oxide may be separated from the gas comprising carbon dioxide of the residual calcination process products.

In other embodiments, injection methods herein may further comprise receiving sensor signals, generating control signals, and communicating control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators, by use of a control unit 126 communicatively coupled to sensors, actuators and other control means. The injection method may further comprise controlling one or more of driving gas supply 105 into the media separated heat exchanger 104, injection gas supply 107 into the injection arrangement 106, heated gas in the particle separator 110, gas pressure in the calcination chamber 108, and/or temperature in the calcination chamber 108 gas supply into the particle separator 110 to support the fluid bed.

The controlling of the gas supply into the particle separator 110 to support the fluid bed may comprise measuring the supplied gas flow. Further, measuring a first pressure above the trap door 203, and measuring a second pressure below the trap door 203 is performed. The difference between the first and the second pressure is calculated, and if the calculated difference is negative, the trap door device is prevented from opening.

Further embodiments of calcination system and method

In embodiments, a calcination system 100 comprising an electrically heated calcination reactor 108 configured to convert input material into calcination process products comprising a solid compound comprising calcium oxide and a gas comprising oxide is provided. The system 100 may further comprise a particle separator 110 arranged to receive input material in the form of particles comprising calcium carbonate. The particle separator 110 comprises a chamber 401 configured

79 to hold a fluid bed 402 of particles mixed with gas, into which fluid bed 402 gas is flowing from underneath 403, thereby separating smaller particles from larger particles by lifting the smaller particles upwards in the flow of gas. The particle separator is coupled to a transfer channel 404 arranged to provide the flow of the separated smaller particles mixed with gas to an injection arrangement 106 injecting the provided input material into the electrically heated calcination reactor 108.

In embodiments, the calcination system 100 may further comprise a media separated heat exchanger 104 coupled to an input 102 and configured to conduct input material in a plurality of channels to the particle separator 110. In embodiments, the calcination system 100 8 9 may further comprise a first heat recovery arrangement 116 configured to receive the calcination process products, to extract heat from the calcination process products and transfer the extracted heat to the input material in the media separated heat exchanger 104. In embodiments, the calcination system 100 may further comprise a second heat recovery arrangement 114 configured to extract heat from solid compound comprising calcium oxide of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas comprising carbon dioxide of the calcination process products, the extracted heat being carried by a gas and inserted into the injection arrangement 106.

In embodiments, the calcination system 100 may further comprise a first separator 112 configured to receive calcination process products from the electrically heated calcination reactor 108 and to separate solid compound comprising calcium oxide from the gas comprising carbon dioxide of the calcination process products. In embodiments, the calcination system 100 may further comprise a second separator 118 configured to receive residual calcination process products output from the first separator 112 and from the first heat recovery system 116, the second separator 118 being configured to further separate solid compound comprising calcium oxide from the gas comprising carbon dioxide of the residual calcination process products.

In embodiments, the calcination system 100 may further comprise a control unit 126 communicatively coupled to sensors and control actuators and configured to receive sensor signals, to generate control signals and to communicate control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators. The control unit may be configured to control one or more of driving gas supply 105 into the media separated heat exchanger 104, injection gas supply 107 into the injection arrangement 106, heated gas in the particle separator 110, gas pressure in the calcination chamber 108, and/or temperature in the calcination chamber 108, and gas supply into the particle separator 110 to support the fluid bed.

According to other aspects, a calcination method for a calcination system 100 is provided. The method comprises receiving input material comprising calcium carbonate, for example in the form of lime mud, separating smaller particles from larger particles of input material in a fluid bed by lifting the smaller particles upwards in a flow of gas, providing the flow of the separated smaller particles mixed with gas to an injection arrangement 106, injecting the separated input material into an electrically heated calcination reactor 108 by use of the injection arrangement 106, converting, in the electrically heated calcination reactor 108, input material into calcination process products comprising a solid compound comprising calcium oxide and a gas comprising carbon dioxide, extracting, in a first heat recovery arrangement 116, heat from the calcination process products and transferring the extracted heat to the input material in the media separated heat exchanger 104, and separating, in one or more separators 112, 118, the solid compound comprising calcium oxide and gas comprising carbon dioxide of the calcination process products.

In embodiments, the calcination method may further comprise extracting, in a second heat recovery arrangement 114, heat from solid compound comprising calcium oxide of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas comprising carbon dioxide of the calcination process products, carrying the extracted heat by a gas and inserting the heat carrying gas into the injection arrangement 106. In embodiments, the calcination method may further comprise separating, in a first separator 112, calcination process products received from the electrically heated calcination reactor 108 such that solid compound comprising calcium oxide may be separated from the gas comprising carbon dioxide of the calcination process products.

In embodiments, the calcination method may further comprise separating, in a second separator 118, residual calcination process products received from the first separator 112 and from the first heat recovery system 116, such that further solid compound comprising calcium oxide may be separated from the gas comprising carbon dioxide of the residual calcination process products. In embodiments, the calcination method may further comprise receiving sensor signals, generating control signals, and communicating control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators, by use of a control unit 126 communicatively coupled to sensors, actuators and other control means. In embodiments, the calcination method may further comprise controlling one or more of driving gas supply 105 into the media separated heat exchanger 104, injection gas supply 107 into the injection arrangement 106, heated gas in the particle separator 110, gas pressure in the calcination chamber 108, and/or temperature in the calcination chamber 108 gas supply into the particle separator 110 to support the fluid bed.

In embodiments, controlling the gas supply into the particle separator 110 to support the fluid bed comprise measuring the supplied gas flow. Further, measuring a first pressure above the trap door device 203, and measuring a second pressure below the trap door device 203 may be performed. The difference between the first and the second pressure is calculated, and if the calculated difference negative, the trap door device 203 is prevented from opening.

Further embodiments of particle separator and method

According to other aspects, a particle separator 110 for use in a calcination system 100 is provided. The calcination system 100 comprises an electrically heated calcination reactor 108 configured to convert input material into calcination process products. The particle separator 110 comprises a chamber 401 configured to hold a fluid bed 402 of particles mixed with gas, into which fluid bed 402 gas is flowing from underneath 403, thereby separating smaller particles from larger particles by lifting the smaller particles upwards in the flow of gas, and wherein the fluid bed 402 is coupled to a transfer channel 404 arranged to provide the flow of the separated smaller particles mixed with gas to an injection arrangement 106 injecting the provided input material into the electrically heated calcination reactor 108.

The particle separator 110 may further be arranged to communicate with a control unit 126 communicatively coupled to sensors and control actuators and configured to receive sensor signals, to generate control signals and to communicate control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators. The control unit may be configured to control one or more of heated gas flow from above into the particle separator 110, and gas flow from underneath 403 into the fluid bed 402. The particle separator 110 may further comprise a trap door device 203 arranged to separate the fluid bed 402 from a container 200 of the particle separator arranged to collect larger particles separated from the fluid bed 402. The particle separator 110 may further comprise a valve arranged to regulate the gas flow from underneath 403 to the fluid bed 402. The particle separator 110, may further comprise a flow regulator regulating the flow of gas through the valve. The flow regulator may be arranged to control the flow of gas through the valve by use of the flow of gas supplied to the fluid bed 402. Measuring a first pressure above the trap door device, and measuring a second pressure below the trap door device 203 may be performed. The difference between the first and the second pressure is calculated, and if the calculated difference is negative, the trap door device is prevented from opening.

According to other aspects, a method for supplying material to a calcination process is provided. The method comprises separating, in a particle separator 110, smaller particles from larger particles of solid compound in input material, wherein the particle separator 110 comprises a chamber 401 configured to hold a fluid bed 402 of particles mixed with gas, into which fluid bed 402 gas may be flowing from underneath 403, thereby separating smaller particles from larger particles by lifting the smaller particles upwards in the flow of gas, and conveying the smaller particles in the gas flow to an injection arrangement 106 for injection into an electrically heated calcination reactor 108.

In embodiments, the method may further comprise controlling the gas flow into the particle separator 110 thereby one or more of regulating a first gas flow flowing into the particle separator 110 via a first gas inlet 201 providing preheated gas, regulating a second gas flow flowing into the particle separator 110 via a second inlet 202 provided preheated gas, whereby the position of the fluid bed may be controlled. In embodiments, the method may further comprise controlling the gas flow into the particle separator 110 by one or more of measuring the concentration of the smaller particles in relation to the flow of gas, regulating gas flow flowing into the particle separator 110 via the first gas inlet 201 providing preheated gas, regulating gas flow flowing into the particle separator 110 via the second inlet 202 provided preheated gas, whereby the concentration of the smaller particles in relation to the flow of gas may be controlled.

Further general embodiments for calcination of different materials

According to other aspects, an injection arrangement 106 in a calcination system 100 is provided. The injection arrangement 106 comprises an injector inlet 202 configured to receive preheated input material comprising carbonate from a media separated heat exchanger 104 into a fluid conductor configured for transferring the preheated input material to an injector 208, the injector 208 being configured to inject the preheated material into an electrically heated calcination reactor 108, and an injection gas 107 supply configured to supply gas for transfer and injection of input material into the electrically heated calcination reactor 108.

The different various details as described herein are applied and combined in different corresponding variants of general embodiments of the injection arrangement and method, for input material comprising carbonate and calcination process products of solid compound comprising oxide and/or gas comprising carbon dioxide.

In embodiments, the injection gas 107 may be preheated in an injection gas tube 210 conducted through the media separated heat exchanger 104.

In embodiments, the inlet 202 may be positioned in a cavity configured to communicate preheated input material from the media separated heat exchanger 104 to a particle separator 110 and may be configured to receive a rising flow of preheated input material in a stream of injection gas 107. In embodiments, the injection gas 107 may be supplied in a flow such that smaller particles may be lifted by the injection gas stream. In embodiments, the injector 208 may be configured to inject the preheated input material into a forma 214 of an electric plasma generator 213 of the electrically heated calcination reactor 108.

In embodiments, the injector 208 may be configured to inject the preheated input material into a calcination chamber 216 of the electrically heated calcination reactor 108 in an input material stream directed tangential in relation to a rotational symmetric cross section of the calcination chamber 216 of the electrically heated calcination reactor 108. In embodiments, the injector inlet 202 and an outlet 218 for the injection gas supply may be positioned at an outlet 220 of the media separated heat exchanger 104.

The system comprises an electrically heated calcination reactor 108, wherein the electrically heated calcination reactor 108 is configured to convert input material comprising a carbonate, for example calcium carbonate, into calcination process products comprising a solid compound comprising oxide, for example calcium oxide and a gas comprising carbon dioxide, and wherein the system 100 may further comprise a particle separator 110 arranged to receive input material comprising carbonate, the particle separator 110 comprises a chamber 401 configured to hold a fluid bed 402 of particles mixed with gas, into which fluid bed 402 gas is flowing from underneath 403, thereby separating smaller particles from larger particles by lifting the smaller particles upwards in the flow of gas, and wherein the particle separator is coupled to a transfer channel 404 arranged to provide the flow of the separated smaller particles mixed with gas to an injection arrangement 106 injecting the provided input material into the electrically heated calcination reactor 108.

According to other aspects, a calcination method for a calcination system 100 is provided. The method comprises receiving input material comprising carbonate, for example calcium carbonate, separating smaller particles from larger particles of input material in a fluid bed by lifting the smaller particles upwards in a flow of gas, providing the flow of the separated smaller particles mixed with gas to an injection arrangement 106, injecting the separated input material into an electrically heated calcination reactor 108 by use of the injection arrangement 106, converting, in the electrically heated calcination reactor 108, input material into calcination process products comprising a solid compound comprising calcium oxide and a gas comprising carbon dioxide, extracting, in a first heat recovery arrangement 116, heat from the calcination process products and transferring the extracted heat to the input material in the media separated heat exchanger 104, and separating, in one or more separators 112, 118, the solid compound comprising calcium oxide and gas comprising carbon dioxide of the calcination process products.

In embodiments, the calcination system 100 may further comprise a media separated heat exchanger 104 coupled to an input 102 and configured to conduct input material in a plurality of channels to the particle separator 110. In embodiments, the calcination system 100 may further comprise a first heat recovery arrangement 116 configured to receive the calcination process products, to extract heat from the calcination process products and transfer the extracted heat to the input material in the media separated heat exchanger 104.

In embodiments, the calcination system 100 may further comprise a second heat recovery arrangement 114 configured to extract heat from solid compound comprising oxide, for example calcium oxide, of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas comprising carbon dioxide of the calcination process products, the extracted heat being carried by a gas and inserted into the injection arrangement 106. In embodiments, the calcination system 100 may further comprise a first separator 112 configured to receive calcination process products from the electrically heated calcination reactor 108 and to separate solid compound comprising oxide from the gas comprising carbon dioxide of the calcination process products. In embodiments, the calcination system 100 may further comprise a second separator 118 configured to receive residual calcination process products output from the first separator 112 and from the first heat recovery system 116, the second separator 118 being configured to further separate solid compound comprising oxide, for example calcium oxide, from the gas comprising carbon dioxide of the residual calcination process products. In embodiments, the calcination system 100 may further comprise a control unit 126 communicatively coupled to sensors and control actuators and configured to receive sensor signals, to generate control signals and to communicate control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators. The control unit may be configured to control one or more of driving gas supply 105 into the media separated heat exchanger 104, injection gas supply 107 into the injection arrangement 106, heated gas in the particle separator 110, gas pressure in the calcination chamber 108, and/or temperature in the calcination chamber 108, and gas supply into the particle separator 110 to support the fluid bed.

According to other aspects, a calcination method for a calcination system 100 is provided. The method comprises receiving input material comprising carbonate, for example calcium carbonate, separating smaller particles from larger particles of input material in a fluid bed by lifting the smaller particles upwards in a flow of gas, providing the flow of the separated smaller particles mixed with gas to an injection arrangement 106, injecting the separated input material into an electrically heated calcination reactor 108 by use of the injection arrangement 106, converting, in the electrically heated calcination reactor 108, input material into calcination process products comprising a solid compound comprising oxide, for example calcium oxide, and a gas comprising carbon dioxide, extracting, in a first heat recovery arrangement 116, heat from the calcination process products and transferring the extracted heat to the input material in the media separated heat exchanger 104, and separating, in one or more separators 112, 118, the solid compound comprising calcium oxide and gas comprising carbon dioxide of the calcination process products.

In embodiments, the calcination method may further comprise extracting, in a second heat recovery arrangement 114, heat from solid compound comprising oxide, for example calcium oxide, of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas comprising carbon dioxide of the calcination process products, carrying the extracted heat by a gas and inserting the heat carrying gas into the injection arrangement 106. In embodiments, the calcination method may further comprise separating, in a first separator 112, calcination process products received from the electrically heated calcination reactor 108 such that solid compound comprising oxide may be separated from the gas comprising carbon dioxide of the calcination process products. In embodiments, the calcination method may further comprise separating, in a second separator 118, residual calcination process products received from the first separator 112 and from the first heat recovery system 116, such that further solid compound comprising oxide may be separated from the gas comprising carbon dioxide of the residual calcination process products. In embodiments, the calcination method may further comprise receiving sensor signals, generating control signals, and communicating control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators, by use of a control unit 126 communicatively coupled to sensors, actuators and other control means.

In embodiments, the calcination method may further comprise controlling one or more of driving gas supply 105 into the media separated heat exchanger 104 injection gas supply 107 into the injection arrangement 106, heated gas in the particle separator 110, gas pressure in the calcination chamber 108, and/or temperature in the calcination chamber 108 gas supply into the particle separator 110 to support the fluid bed. In embodiments, controlling the gas supply into the particle separator 110 to support the fluid bed may comprise measuring the supplied gas flow. Measuring a first pressure above the trap door device, and measuring a second pressure below the trap door device 203 may be performed. The difference between the first and the second pressure is calculated, and if the calculated difference is negative, the trap door device is prevented from opening.

The different various details as described herein are applied and combined in different corresponding variants of general embodiments of a calcination system and method, for input material comprising carbonate and calcination process products of solid compound comprising oxide and/or gas comprising carbon dioxide.

Further embodiments of heat recovery arrangement and method

According to other aspects, a heat recovery arrangement 114 for heat recovery in a system 100 for calcination of material comprising calcium carbonate, for example in the form of lime mud, is provided. The heat recovery arrangement 114 comprises an inlet 402 for receiving incoming gas from the system 100 for calcination of material comprising calcium carbonate, for example in the form of lime mud, an expander 404 for expanding and thereby cooling by expansion the incoming gas, a heat recovery tube 406 arranged in a container 408 comprising solid material comprising calcium oxide extracted from the system 100 for calcination of material comprising calcium carbonate, for example in the form of lime mud, into which recovery tube 410 the expanded and cooled gas is led and heated by the heat from the solid material comprising calcium oxide, a compressor 412 for compressing and further heating the heated gas, an outlet 414 from which the compressed and further heated gas is led out, whereby heat generated from the calcination process is reused.

In embodiments, the incoming gas may be preheated by excess heat generated by the system 100 for calcination of material comprising calcium carbonate, for example in the form of lime mud. In embodiments, the incoming gas pressurized to a pressure of approximately 4 bar (a). In embodiments, the compressed gas may be decompressed by a diffusor 418 and reentered into the system 100 for calcination of material comprising calcium carbonate, for example in the form of lime mud. In embodiments, the incoming gas comprises carbon dioxide and/or water vapor. In embodiments, the outcoming gas has a temperature of approximately 1000 - 1300 degrees Celsius and a pressure of approximately 2 bar (a). In embodiments, the compressor 412 may be arranged inside a housing 420.

According to other aspects, a method for heat recovery in a system 100 for calcination of material comprising calcium carbonate, for example in the form of lime mud, is provided. A heat recovery arrangement 114 comprises an inlet 402, an outlet 414, an expander 404, and a compressor 412, and the method comprises receiving incoming gas via the inlet 402 from the system 100 for calcination of material comprising carbonate, expanding in the expander 404 and thereby cooling by expansion the incoming gas, leading and heating the expanded and cooled gas via a heat recovery tube 406 arranged in a container 408 comprising solid material comprising oxide extracted from the system 100 for calcination of material comprising carbonate, whereby the expanded and cooled gas is heated by the heat from the solid material comprising calcium oxide, compressing and further heating the preheated gas in the compressor 412, leading out the compressed and further heated gas via the outlet 414, reenter the decompressed gas into the system 100 for calcination of material comprising carbonate, whereby heat generated from the calcination process is reused.

In embodiments, the incoming gas may be preheated by excess heat generated by the system 100 for calcination of material comprising carbonate. In embodiments, the heat recovery arrangement 114 may further comprise a diffusor 418, and the method may further comprise decompressing the led out gas by the diffusor 418.

General embodiments of more aspects and embodiments of heat recovery arrangement and method

According to other aspects, a heat recovery arrangement 114 for heat recovery in a system 100 for calcination of material comprising carbonate is provided. The heat recovery arrangement 114 comprises an inlet 402 for receiving incoming gas from the system 100 for calcination of material comprising carbonate, an expander 404 for expanding and thereby cooling by expansion the incoming gas, a heat recovery tube 406 arranged in a container 408 comprising solid material comprising oxide extracted from the system 100 for calcination of material comprising carbonate, into which recovery tube 410 the expanded and cooled gas is led and heated by the heat from the solid material comprising oxide, a compressor 412 for compressing and further heating the heated gas, an outlet 414 from which the compressed and further heated gas is led out, whereby heat generated from the calcination process is reused.

In embodiments, the incoming gas may be preheated by excess heat generated by the system 100 for calcination of material comprising carbonate. In embodiments, the incoming gas pressurized to a pressure of approximately 4 bar (a) before expanding and preheating. In embodiments, the expanded, heated and again compressed gas may be decompressed by a diffusor 418 and reentered into the system 100 for calcination of material comprising carbonate. In embodiments, the incoming gas may comprise carbon dioxide and/or water vapor. In embodiments, the outcoming gas has a temperature of approximately 1000 - 1300 degrees Celsius and a pressure of approximately 2 bar (a). In embodiments, the compressor 412 may be arranged inside a housing 420.

According to other aspects, a method for heat recovery in a system 100 for calcination of material comprising carbonate is provided. A heat recovery arrangement 114 comprises an inlet 402, an outlet 414, an expander 404, and a compressor 412. The method comprises receiving incoming gas via the inlet 402 from the system 100 for calcination of material comprising carbonate, expanding in the expander 404 and thereby cooling by expansion the incoming gas, leading and heating the expanded and cooled gas via a heat recovery tube 406 arranged in a container 408 comprising solid material comprising oxide extracted from the system 100 for calcination of material comprising carbonate, whereby the expanded and cooled gas may be heated by the heat from the solid material comprising calcium oxide, compressing and further heating the heated gas in the compressor 412, leading out the compressed and further heated gas via the outlet 414, reenter the decompressed gas into the system 100 for calcination of material comprising carbonate, whereby heat generated from the calcination process may be reused. In embodiments, the incoming gas may be preheated by excess heat generated by the system 100 for calcination of material comprising carbonate. In embodiments, the heat recovery arrangement 114 may further comprise a diffusor 418, and the method may further comprise decompressing the led out gas by the diffusor 418.

The different various details as described herein are applied and combined in different corresponding variants of general embodiments of a heat recovery arrangement and method, for input material comprising carbonate and calcination process products of solid compound comprising oxide and/or gas comprising carbon dioxide.

More aspects and embodiments of calcination system and method.

According to other aspects, a calcination system 100 is provided. The system comprises an input 102 for receiving input material comprising calcium carbonate, for example in the form of lime mud, a media separated heat exchanger 104 coupled to the input and configured to conduct input material in a plurality of channels, an injection arrangement 106 configured to receive input material from the media separated heat exchanger 104 and to inject input material into an electrically heated calcination reactor 108. The electrically heated calcination reactor 108 is configured to convert input material received by means of the injection arrangement 106 into calcination process products comprising a solid compound comprising calcium oxide and a gas comprising carbon dioxide.

In embodiments, the system 100 may further comprise a first heat recovery arrangement 116 configured to receive the calcination process products, to extract heat from the calcination process products and transfer the extracted heat to the input material in the media separated heat exchanger 104, and one or more separators 112, 118 configured to separate the solid compound comprising calcium oxide and gas comprising carbon dioxide of the calcination process products. In embodiments, the media separated heat exchanger 104 may be arranged to heat input material comprising calcium carbonate by heat transfer from hot gas mixed with calcium oxide, the media separated heat exchanger comprising an outer shell 302, one or more tubes 304 arranged inside the shell 302, into which tubes 304 a first medium for heat transfer may be fed and flows during heat transfer, and wherein a second medium for heat transfer flows outside the tubes. In embodiments, the first medium may be hot gas mixed with calcium oxide and the second medium may be input material comprising calcium carbonate. Alternatively, the first medium may be input material comprising calcium carbonate and the second medium may be hot gas mixed with calcium oxide. In embodiments, the heat exchanger 104 may further comprise one or more primary inlets 306 for feeding hot gas mixed with calcium oxide used for the heat transfer, wherein the hot gas and calcium oxide may be received from a calcination reactor and/or a cyclone comprised in the system for calcination of input material comprising calcium carbonate, and an outlet 308 for feeding heated input material comprising calcium carbonate into the reactor 108.

In embodiments, the media separated heat exchanger 104 may further comprise a distributor 310 for feeding and distributing input material comprising calcium carbonate into the media separated heat exchanger 104. The distributor 310 may be moveable. The distributor 310 may be arranged to distribute and feed input material into the on more tubes 304. In embodiments, the media separated heat exchanger 104 may further comprise one or more secondary inlets for feeding gas from an external supply into the media separated heat exchanger 104.

In embodiments, the one or more tubes 304 may be provided with an arrangement for providing a turbulent flow of the medium flowing inside and/or outside the tubes 304. The arrangement may be one or more moveable chains, whereby a turbulent flow of the medium may be achieved. The one or more moveable chains may be arranged inside the tubes 304. The one or more moveable chains may be arranged outside the tubes 304. In embodiments, the inner side of the shell 302 may be provided with irregularities in the surface, whereby a turbulent flow of the second medium may be provided. In embodiments, the calcination system 100 may further comprise a second heat recovery arrangement 114 configured to extract heat from solid compound comprising calcium oxide of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas comprising carbon dioxide of the calcination process products, the extracted heat being carried by a gas and inserted into the injection arrangement 106. In embodiments, the calcination system 100 may further comprise a first separator 112 configured to receive calcination process products from the electrically heated calcination reactor 108 and to separate solid compound comprising calcium oxide from the gas comprising carbon dioxide of the calcination process products. In embodiments, the calcination system 100 may further comprise a second separator 118 configured to receive residual calcination process products output from the first separator 112 and from the first heat recovery system 116, the second separator 118 being configured to further separate solid compound comprising calcium oxide from the gas comprising carbon dioxide of the residual calcination process products.

In embodiments, the calcination system 100 may further comprise a particle separator 110 coupled to the injection arrangement 106 and configured to separate larger lumps and smaller particles of solid compound in input material, and to convey the smaller particles in a gas flow to the injection arrangement 106 for injection into the electrically heated calcination reactor 108. In embodiments, the calcination system 100 may further comprise a filter arrangement 122 configured to receive gas of calcination process products comprising carbon dioxide from the one or more separators and to filter the gas to a higher degree of purity. In embodiments, the calcination system 100 may further comprise a steam boiler 120 configured to extract heat from calcination process products from the first heat recovery arrangement 116 and to generate steam. In embodiments, the calcination system 100 may further comprise a control unit 126 communicatively coupled to sensors and control actuators and configured to receive sensor signals, to generate control signals and to communicate control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators. The control unit may be configured to control one or more of gas supply 105 into the media separated heat exchanger 104, injection gas supply 107 into the injection arrangement 106, heated gas in the particle separator 110, gas pressure in the calcination chamber 108, and/or temperature in the calcination chamber 108.

According to other aspects, a calcination method comprising receiving input material comprising calcium carbonate, for example in the form of lime mud is provided. The calcination method comprises conducting the input material in a plurality of channels of a media separated heat exchanger 104, injecting input material into an electrically heated calcination reactor 108, converting, in the electrically heated calcination reactor 108, input material into calcination process products comprising a solid compound comprising calcium oxide and a gas comprising carbon dioxide, extracting, in a first heat recovery arrangement 116, heat from the calcination process products and transferring the extracted heat to the input material in the media separated heat exchanger 104, and separating, in one or more separators 112, 118, the solid compound comprising calcium oxide and gas comprising carbon dioxide of the calcination process products.

In embodiments, the calcination method may further comprise extracting, in a second heat recovery arrangement 114, heat from solid compound comprising calcium oxide of the calcination process products output from the electrically heated calcination reactor 108 and separated from the gas comprising carbon dioxide of the calcination process products, carrying the extracted heat by a gas and inserting the heat carrying gas into the injection arrangement 106. In embodiments, the media separated heat exchanger may comprise an outer shell 302 and one or more tubes 304 arranged inside the shell 302, and the method may further comprise feeding and flowing a first medium for heat transfer into the tubes 304 during heat transfer, and feeding and flowing a second medium for heat transfer outside the tubes. The first medium may be hot gas mixed with calcium oxide and the second medium may be input material comprising calcium carbonate. Alternatively, the first medium may be input material comprising calcium carbonate and the second medium may be hot gas mixed with calcium oxide.

In embodiments, the calcination method may further comprise separating, in a first separator 112, calcination process products received from the electrically heated calcination reactor 108 such that solid compound comprising calcium oxide may be separated from the gas comprising carbon dioxide of the calcination process products. In embodiments, the calcination method may further comprise separating, in a second separator 118, residual calcination process products received from the first separator 112 and from the first heat recovery system 116, such that further solid compound comprising calcium oxide may be separated from the gas comprising carbon dioxide of the residual calcination process products. In embodiments, the calcination method may further comprise separating, in a particle separator 110 coupled to the injection arrangement 106, such that larger lumps and smaller particles of solid compound in input material may be separated, and conveying the smaller particles in a gas flow to the injection arrangement 106 for injection into the electrically heated calcination reactor 108.

In embodiments, the calcination method may further comprise filtering, in a filter arrangement 122 gas of calcination process products comprising carbon dioxide received from the one or more separators, such that the gas may be filtered to a higher degree of purity. In embodiments, the calcination method may further comprise extracting, in a steam boiler 120, heat from calcination process products from the first heat recovery arrangement 116 and generating steam. The calcination method may further comprise in a control unit 126 communicatively coupled to sensors and control actuators, receiving sensor signals, generating control signals and communicating control signals through a control port 128 connected to one or more signal lines 130 coupled to the sensors and control actuators. The calcination method may further comprise controlling one or more of gas supply 105 into the media separated heat exchanger 104, injection gas supply 107 into the injection arrangement 106, heated gas in the particle separator 110, gas pressure in the calcination chamber 108, and/or temperature in the calcination chamber 108.

General embodiments of more aspects and embodiments of calcination system and method

According to other aspects, a calcination system 100 comprising an input 102 for receiving input material comprising carbonate is provided. The system 100 comprises a media separated heat exchanger 104 coupled to the input and configured to conduct input material in a plurality of channels and an injection arrangement 106 configured to receive input material from the media separated heat exchanger 104 and to inject input material into an electrically heated calcination reactor 108. The electrically heated calcination reactor 108 is configured to convert input material received by means of the injection arrangement 106 into calcination process products comprising a solid compound comprising oxide and a gas comprising carbon dioxide. The system 100 comprises a first heat recovery arrangement 116 configured to receive the calcination process products, to extract heat from the calcination process products and transfer the extracted heat to the input material in the media separated heat exchanger 104, and one or more separators 112, 118 configured to separate the solid compound comprising oxide and gas comprising carbon dioxide of the calcination process products.

According to other aspects, a calcination method comprising receiving input material comprising carbonate is provided. The method comprise conducting the input material in a plurality of channels of a media separated heat exchanger 104, injecting input material into an electrically heated calcination reactor 108, converting, in the electrically heated calcination reactor 108, input material into calcination process products comprising a solid compound comprising oxide and a gas comprising carbon dioxide, extracting, in a first heat recovery arrangement 116, heat from the calcination process products and transferring the extracted heat to the input material in the media separated heat exchanger 104, and separating, in one or more separators 112, 118, the solid compound comprising oxide and gas comprising carbon dioxide of the calcination process products.

The foregoing disclosure is not intended to limit the present disclosure to the precise forms or particular fields of use disclosed. It is contemplated that various alternate embodiments and/or modifications to the present embodiments, whether explicitly described or implied herein, are possible in the light of the disclosure. Accordingly, the scope of is defined only by the accompanying patent claims.