FIELD

The invention relates to the method defined in claim 1 and the apparatus defined in claim 10 for recovering and using oxygen in combustion utilising oxygen as well as the use of the method defined in claim 13.

BACKGROUND

Previously are known different methods for separating and recovering carbon dioxide from a gaseous flow or from the air. In addition, the publication WO 2017/140954 discloses the recovery of carbon dioxide from air of a building.

Previously is also known combustion utilising oxygen in various apparatuses intended for combustion. OBJECT

The object of the invention is to present a novel method for recovering oxygen in connection with the processing of carbon dioxide and to utilise the oxygen recovered efficiently. Another object of the invention is to present a novel apparatus for recovering and utilising oxygen energy-efficiently . A further object of the invention is to present a method and an apparatus for improving combustion utilising oxygen and to reduce emissions. A further object of the invention is to present an environmentally friendly and essentially emission-free way of using internal combustion engines, fuel cells and turbines for generating heat and electricity. A further object of the invention is to enhance the overall utilisation of carbon dioxide recovered from the air, a gas or a fluid. SUMMARY

The method and apparatus for recovering and using oxygen in combustion utilising oxygen as well as the use of the method according to the invention are characterised by what is disclosed in the claims.

Oxygen is formed in connection with the processing of recovered carbon dioxide, the oxygen is recovered and the oxygen is conveyed to combustion utilising oxygen.

DE TAILED DE SCRI PTION

In the method according to the invention for recovering and using oxygen in combustion utilising oxygen, oxygen is formed in connection with the processing of carbon dioxide recovered from the air, a gas or a fluid, the oxygen is recovered and the oxygen is conveyed to combustion utilising oxygen. The carbon dioxide is recovered from the air, for example, outdoor air, air conveyed into a building and/or air circulated in a building, from a gas, for example, a combustion gas and/or flue gas, or from a fluid, for example water, and pure oxygen is formed in connection with the processing of the recovered carbon dioxide. The pure oxygen is recovered and the oxygen is conveyed to combustion utilising oxygen. By means of the method according to the invention, pure oxygen can be formed simultaneously with the recovery of carbon dioxide. Furthermore, by means of the method according to the invention, emissions can be reduced and cleaner combustion achieved at the combustion stage taking place by utilising oxygen.

The invention is, in addition, based on an apparatus comprising at least one carbon dioxide processing device for processing recovered carbon dioxide to form a chemical compound, at least one oxygen-forming device for forming oxygen in connection with the processing of the recovered carbon dioxide, and at least one combustion device into which the oxygen is conveyed and in which the fuel is combusted in the presence of oxygen.

In this connection, combustion by utilising oxygen refers to any combustion taking place in the presence of oxygen.

In one embodiment, the method comprises an oxygen-forming stage. In one embodiment, oxygen is formed of water. In one embodiment, oxygen is formed of water recovered in connection with the processing of carbon dioxide.

In one embodiment, oxygen is formed by means of electrolysis. In the electrolysis, oxygen and hydrogen are preferably formed of water. The hydrogen formed in the electrolysis is preferably conveyed to the carbon dioxide processing stage in which a chemical compound is formed of carbon dioxide by means of hydrogen. The water required for the electrolysis may be derived from the water recovered from the processing of carbon dioxide, such as from the water recovered at the carbon dioxide processing stage and/or from the water separated in connection with the recovery of the carbon dioxide. Alternatively, the water required for the electrolysis may be derived partly or completely, or alternatively intermittently, from any suitable raw material source, for example, the water supply system, rainwater system or exhaust air system or other suitable source.

In one embodiment, the apparatus comprises at least one electrolyser serving as an oxygen-forming device. Oxygen and hydrogen are preferably formed of water in the electrolyser. In this connection can be used any suitable electrolysis method and device known in the art for producing oxygen and hydrogen. In one embodiment, the apparatus comprises at last one means for conveying the water recovered at the carbon dioxide processing stage and/or from the air, for example, from air conveyed into a building and air circulated in a building, or from gas, such as a combustion gas, or from water removed from a fluid, into the electrolyser .

Carbon dioxide is preferably recovered from the air, a gas or a fluid and supplied to the carbon dioxide processing stage. In one embodiment, carbon dioxide is processed by hydrogen processing, for example by means of hydrogen, at the processing stage, in order to form a chemical compound. In one embodiment, a chemical compound, such as an organic and/or inorganic compound, is formed of carbon dioxide at the carbon dioxide processing stage. In one embodiment, a hydrocarbon is formed at the carbon dioxide processing stage. In one embodiment, methane (CH ₄₎ is formed at the carbon dioxide processing stage. In one embodiment, at the carbon dioxide processing stage is formed another suitable hydrocarbon or, for example, an alcohol-based compound or other oxygen-containing compound. In one embodiment, carbon dioxide processing is carried out by means of chemical synthesis either in the presence of a catalyst or without a catalyst. At the carbon dioxide processing stage can be used any device known in the art as such and suitable for the purpose, in which device can preferably be arranged conditions suitable for the process or synthesis, such as pressure and temperature.

In one embodiment, the hydrogen formed in electrolysis is conveyed to the carbon dioxide processing stage. In one embodiment, the apparatus comprises means for conveying hydrogen from the electrolyser to the carbon dioxide processing device.

In one embodiment, the chemical compound produced at the carbon dioxide processing stage, for example a hydrocarbon, is recovered and/or processed further. In one embodiment, at the carbon dioxide processing stage is formed hydrocarbon, for example methane (CfU) , which can be used as raw material or fuel, for example, in an internal combustion engine.

In one embodiment, the recovered carbon dioxide, for example, carbon dioxide recovered from the combustion gases of combustion utilising oxygen, can be stored and utilised later, for example, at the carbon dioxide processing stage and/or in producing a hydrocarbon .

In one embodiment, recovered water is conveyed from the carbon dioxide processing stage to electrolysis, where oxygen and hydrogen are formed of the water. In one embodiment, the apparatus comprises at least one water supply device for supplying or circulating water from the carbon dioxide processing device to the oxygen-forming device, for example, an electrolyser .

In one embodiment, the heat generated at the carbon dioxide processing stage is conveyed as process heat to the desired process stages.

Separating carbon dioxide from the air, a gas or a fluid can be carried out by means of any separation device known as such in the art and suitable for the purpose. The separation device may be any separation or recovery device known as such in which the separation of carbon dioxide from the air, a gas or a fluid may be based on a chemical process, a physical process, an absorption process, a dissolving process, a membrane process, other suitable process or their combinations. In one embodiment, the separation of carbon dioxide from the air or a gas can be carried out by means of a scrubber. In one embodiment, the separation of carbon dioxide from the air, a gas or a fluid can be carried out by means of a solid chemically active substance. As a supply device for supplying air, gas or fluid to the separation device can be used any device or equipment suitable for the purpose and known in the art by means of which air, gas or fluid can be conveyed or drawn into the separation device or through it. As means for recovering carbon dioxide from the separation device and conveying it to the carbon dioxide processing stage can be used any means known as such and suitable for the purpose, for example, a discharge pipe, a discharge fitting, a recovery device, a supply device or similar means or their combinations. In one embodiment, the apparatus comprises a separation device for separating carbon dioxide from the air, a gas or a fluid, at least one carbon dioxide processing device, and at least one means for recovering carbon dioxide from the separation device and conveying it to the processing device.

In one embodiment, carbon dioxide is recovered from the air, a gas or a fluid and the carbon dioxide is conveyed to the carbon dioxide processing stage. In one embodiment, carbon dioxide is recovered from the air, such as the air conveyed into a building and/or circulated in a building, and the carbon dioxide is conveyed to the carbon dioxide processing stage. In one embodiment, carbon dioxide is recovered from a gas, such as a combustion gas or a flue gas, for example, the combustion gas from an internal combustion engine, fuel cell or turbine, and the carbon dioxide is conveyed to the carbon dioxide processing stage. In one embodiment, the carbon dioxide is recovered from a fluid, which may be a mixture of a liquid and a gas or a pure liquid, for example, seawater, and the carbon dioxide is conveyed to the carbon dioxide processing stage .

In one embodiment, water is removed from the air, a gas or a fluid in connection with the recovery of carbon dioxide and the water is conveyed to electrolysis, where oxygen and hydrogen are formed of the water. In one embodiment, water is removed from a gas, for example, a combustion gas or a flue gas, in connection with the recovery of carbon dioxide, and the water is conveyed to electrolysis. In one embodiment, water is removed from the air, such as the air conveyed into a building and/or the air circulated in a building, in connection with the recovery of carbon dioxide and the water is conveyed to electrolysis, where oxygen and hydrogen are formed of the water. The humidity of indoor air in the building can thus be reduced. In one embodiment, the apparatus comprises at least one other water supply device for conveying water removed from the air, a gas or a fluid to an oxygen-forming device, for example, an electrolyser .

The oxygen formed is preferably conveyed to combustion utilising oxygen. In one embodiment, the apparatus comprises an oxygen supply device for conveying the oxygen from the oxygen-forming device to the combustion device. In one embodiment, the oxygen formed is stored intermediately and used after intermediate storage in combustion utilising oxygen. In one embodiment, the oxygen formed is conveyed to combustion taking place in an internal combustion engine, fuel cell or turbine by utilising oxygen, where energy, such as kinetic energy and thermal energy are produced of the fuel. In this connection, the internal combustion engine may be any internal combustion engine. In one embodiment, the internal combustion engine is a diesel engine or a fuel oil engine. In one embodiment, the internal combustion engine is a piston engine. In one embodiment, the internal combustion engine is a gas engine. In one embodiment, the turbine is a gas turbine. In combustion utilising oxygen in an internal combustion engine, a fuel cell or a turbine, fuel can used to produce thermal energy, for example, for providing real estate heating or district heating. Any fuel together with the pure oxygen formed can be used as fuel in an internal combustion engine, fuel cell or turbine. The fuel may be derived from any raw material, for example, fossil raw material. In one embodiment, the fuel is diesel or fuel oil or fuel made of them. Alternatively, a chemical compound produced at the processing stage of carbon dioxide, such as hydrocarbon, can be used as fuel.

In one embodiment, the apparatus comprises at least one generator which converts the mechanical kinetic energy of an internal combustion engine, fuel cell or turbine into an electric current.

In one embodiment, the exhaust gases of an internal combustion engine, fuel cell or turbine are conveyed to a refrigerating machine, for example, an absorption chiller. In one embodiment, the refrigerating machine is selected so that its operation is based on absorption cooling, where thermal energy having a temperature higher than the ambient temperature is used for the cooling.

In one embodiment, carbon dioxide is recovered from the combustion gases of an internal combustion engine, a fuel cell or a turbine. The recovered carbon dioxide can be stored or conveyed to the carbon dioxide processing stage according to the invention. In one embodiment, the combustion gases of an internal combustion engine, for example, a diesel or piston engine, are left under pressure, that is, the pressure of the combustion gases is left higher, whereupon the liquefaction point of carbon dioxide is closer to zero, thus providing significant energy savings in liquefaction .

In an alternative embodiment, the oxygen formed can be conveyed to different stages of the process, such as the carbon dioxide processing stage, should there be need for it. In one embodiment, the oxygen formed is stored intermediately, for example in bottles, and used for the desired purpose, for example, for combustion utilising oxygen, as industrial oxygen or as a bottled oxygen product.

In one embodiment, the heat generated in forming oxygen and hydrogen, for example in electrolysis or synthesis, is conveyed to the carbon dioxide separation stage, for heating a building, for example, to the service water of a building, or to a suitable process stage.

Any available energy can be used as the energy required for electrolysis. In one embodiment, the energy generated by a wind turbine or a solar cell device is used as the electricity required for electrolysis. In one embodiment, so-called surplus electricity, which is electricity generated in excess with respect to the electricity consumption, is used as the electricity required for electrolysis. In one embodiment, electrolysis is used flexibly to regulate the frequency of the electrical grid. Electrolysis can, therefore, act as a buffer in electricity generation, where the electrolysis stage is implemented when surplus electricity is available.

In one embodiment, the apparatus comprises a shell construction, for example, walls, a floor and a ceiling inside which the equipment parts of the apparatus can be arranged. In one embodiment, the apparatus can be arranged in a transport container or similar easily movable and/or transportable space. In one embodiment, the apparatus functions as its own unit which can be easily moved and/or located to the desired site of use.

The method and apparatus according to the invention can be used in recovering carbon dioxide, in processing the indoor air of a building, in producing hydrocarbons, in recovering oxygen, in combustion utilising oxygen, in recovering carbon dioxide formed during combustion, in producing energy, in generating heat, in a property-specific energy production system, for example, a heat supply system, a building complex specific energy production system and their combinations .

In this connection, a building complex refers to any property or building, such as a residential building, an industrial building, a warehouse, office premises, a public building or other similar building, or a consortium consisting of more than one building.

In the method and apparatus according to the invention, the different material flows can be recycled and made into new raw materials or products. Owing to the invention, pure oxygen can be formed simultaneously with the recovery and/or processing of carbon dioxide. According to the invention, oxygen can be formed ecologically of various material flows, such as recyclable and/or recovered material flows. Furthermore, for example from the air can be recovered pure carbon dioxide and from it can be formed pure hydrocarbons. Pure oxygen can also be formed of the water separated in the recovery or processing of carbon dioxide recovered from air. High-quality hydrocarbons can be used, for example, for purposes requiring pure fuels.

Furthermore, owing to the invention, a pure and emission-free combustion process can be achieved in combustion utilising oxygen, for example, in an internal combustion engine, fuel cell or turbine. By using the oxygen formed instead of air in the combustion, emissions can be significantly reduced with each fuel. In combustion utilising oxygen according to the invention, significantly less or no nitrogen oxides are formed. Furthermore, in the embodiment according to the invention, exhaust gases are not discharged into the environment, but their thermal energy and the carbon dioxide in the exhaust gases can be utilised.

Owing to the invention, total emissions of carbon dioxide can be reduced. Furthermore, in the process according to the invention, carbon dioxide emissions can be significantly reduced or practically no carbon dioxide emissions are produced.

The apparatus according to the invention can be implemented easily and cost-effectively. The apparatus can also be easily incorporated in connection with buildings and building complexes.

LIST OF FIGURES

Figure 1 shows an apparatus according to the invention, and

Figure 2 shows another apparatus according to the invention.

EXAMPLES

The invention is described in the following with detailed examples of embodiments, with reference to the accompanying Figures.

Example 1

In the apparatus of Fig. 1, oxygen (6) is formed in connection with the processing of recovered carbon dioxide (1), the oxygen (6) is recovered and conveyed to combustion utilising oxygen. In this embodiment, carbon dioxide (1) is recovered from air to be conveyed into a building and/or from air to be circulated in the building, and the recovered carbon dioxide (1) is processed with hydrogen (7) in a processing device (2) at the processing stage to form hydrocarbons (4) . Alternatively, or in addition, carbon dioxide can be recovered from gases, for example, from combustion gases. The water (3) separated at the processing stage is conveyed by means of a water supply device to an oxygen-forming device, such as an electrolyser (5) . The pure oxygen (6) formed is conveyed to a combustion device (8), such as an internal combustion engine, or alternatively, for example, to a fuel cell or a turbine. The hydrogen formed in the electrolyser in addition to oxygen can be recycled as hydrogen (7) into the processing device (2) . The electricity required for electrolysis may be, for example, surplus electricity from electricity production, for example, from a wind turbine or a solar cell device.

The apparatus comprises an oxygen supply device for conveying oxygen (6) from the oxygen forming device to the combustion device (8) . The apparatus further comprises a fuel (9) supply device for supplying fuel to the combustion device (8) . In this embodiment, the combustion device (8) may be an internal combustion engine, such as a diesel internal combustion engine or a gas internal combustion engine, where the fuel (9), for example, diesel or methane gas is combusted in the presence of oxygen (6) . The fuel may be derived from any raw material, for example, a fossil raw material, or alternatively, a chemical compound formed at the carbon dioxide processing stage, such as hydrocarbon (4), can be used as fuel. The energy (11) generated, such as mechanical kinetic energy or thermal energy, is recovered. Thermal energy can be utilised, for example, in property-specific heating or district heating. The exhaust gases (10) produced in combustion can be conveyed by means of a suitable compressor or feeding device to a refrigerating machine (12), such as an absorption chiller, either directly or through heat recovery. If the exhaust gases are conveyed to the refrigerating machine through heat recovery, the recovered heat can be utilised in the refrigerating machine or at another desired process stage. From the refrigerating machine (12) the gas (13) can be recycled by means of a gas recycling device back to the fuel supply of the internal combustion engine. Carbon dioxide from the refrigerating machine can be recovered and utilised as a product or as raw material. Alternatively, carbon dioxide can be recovered from the exhaust gases and conveyed to the carbon dioxide processing stage.

By means of the apparatus of Fig. 1 can be formed pure oxygen, which can be used in combustion utilising oxygen to achieve combustion with less emissions. The exhaust gases from combustion can be used as raw material or, for example, in refrigerating machines .

Example 2

In the apparatus of Fig. 2, oxygen (6) is formed in connection with the processing of the recovered carbon dioxide (1), the oxygen (6) is recovered and conveyed to combustion utilising oxygen. In this embodiment, carbon dioxide (1) is recovered from air conveyed into a building and/or air circulated in the building, and the recovered carbon dioxide (1) is processed with hydrogen (7) in a processing device (2) at the processing stage to form a chemical compound (15) which may be a hydrocarbon. Alternatively, or in addition, carbon dioxide can be recovered from gases, for example, from combustion gases .

Water (3, 3b) separated from the air conveyed into a building and/or circulated in a building is conveyed by means of a second water supply device to an oxygen-forming device, such as an electrolyser (5) . The apparatus may comprise means for removing water from the air conveyed into the building in connection with separating carbon dioxide. It may also be possible to convey water (3, 3a) separated at the processing stage to the oxygen-forming device by means of a water supply device. The pure oxygen (6) formed is conveyed to a combustion device (8), such as an internal combustion engine, or alternatively to a fuel cell or turbine. The hydrogen formed in the electrolyser in addition to oxygen is recycled as hydrogen (7) into the processing device (2) . The electricity required for electrolysis may be, for example, surplus electricity from electricity production, for example, from a wind turbine or a solar cell device.

The apparatus comprises an oxygen supply device for conveying oxygen (6) from the oxygen forming device to the combustion device (8) . The apparatus also comprises a fuel (9) supply device for supplying fuel to the combustion device (8) . In this embodiment, the combustion device (8) may be an internal combustion engine, such as a diesel internal combustion engine or a gas internal combustion engine, where the fuel (9), for example, diesel or methane gas, is combusted in the presence of oxygen (6) . The fuel may be derived from any raw material, for example, a fossil raw material, or alternatively, a chemical compound formed at the carbon dioxide processing stage, such as hydrocarbon, can be used as fuel. The energy (11) generated, such as mechanical kinetic energy or thermal energy, is recovered. Thermal energy can be utilised, for example, in property-specific heating or district heating. The exhaust gases (10) produced in combustion can be conveyed by means of a suitable compressor or feeding device to a refrigerating machine (12), such as an absorption chiller, either directly or through heat recovery. If the exhaust gases are conveyed to the refrigerating machine through heat recovery, the recovered heat can be utilised in the refrigerating machine or at another desired process stage. From the refrigerating machine (12), the gas (13) can be recycled by means of a gas recycling device back to the fuel supply of the internal combustion engine. Carbon dioxide from the refrigerating machine can be recovered and utilised as a product or as raw material. Alternatively, carbon dioxide can be recovered from the exhaust gases and conveyed to the carbon dioxide processing stage.

With the apparatus of Fig. 2 can be formed pure oxygen, which can be used in combustion utilising oxygen to achieve combustion with less emissions. The exhaust gases from the combustion can be utilised as raw material or, for example, in refrigerating machines .

The method and apparatus according to the invention are applicable, as different embodiments, for use in a wide range of applications in connection with combustion utilising oxygen and in connection with the processing of carbon dioxide. Furthermore, the method and apparatus according to the invention are applicable, as different embodiments, for use in connection with a wide variety of processes utilising oxygen .

The invention is not only limited to the above examples, but various modifications are possible within the scope of the inventive idea specified in the claims.