HYDROCARBONS COMPRISING MASS

The invention relates to a system for thermal cracking of a hydrocarbons comprising mass. The invention also relates to a method for thermal cracking of a

hydrocarbons comprising mass, preferably by using the system according to the invention.

When combustible materials as for example biomass, coal and waste, are heated in a closed vessel or chamber, the molecular structure disintegrates. The products of this thermal cracking process are combustible gasses at ambient temperature, such as hydrogen and carbon monoxide, liquid products, as a variety of hydrocarbons and tar, and charred material (char) . This process, thermal cracking, is a basic known process, also known as

pyrdlysis. With gasification processes, (enriched) air or oxygen is added insufficiently for a complete combustion, giving the same products as with thermal cracking, but giving more gaseous products and less or no liquid products or char.

Thermal cracking is a technique that can be used to produce different products from biomass, waste and other combustible materials. With thermal cracking, gaseous products, liquid products and/or char can be obtained.

Gaseous products can be used as a fuel or as a feedstock for chemical processes as for example methanol production. The liquid products could be used as a fuel for boilers or transportation, if the product has the desired properties. Charred material can be used as boiler fuel, consumer' s coal for example for barbeques or reduction material.

Charring material makes the release of metals from for example electronics waste less complex and makes a higher yield of metals possible. Gasification of biomass and waste has the objective to produce a combustible gas as a gaseous fuel and/or to process waste.

The problems with many thermal cracking processes are: the design of a process capable of producing only one product, the liquids obtained from the thermal cracking process not having the desired properties, and the

synthesis gas in many cases containing tar, giving clogging problems in various applications.

Many patented thermal cracking processes solve some mentioned processes but not all sufficiently. Some thermal cracking processes produce oil as well as synthesis gas. The yield however depends on the input and the process temperature, but not on the return of oil to the thermal cracking process.

It is an object of the invention to provide a relatively efficient system and method for thermal cracking of a hydrocarbons comprising mass.

This object can be achieved by providing a system according to claim 1 and by providing a method according to claim 14. With the process the quality and quantity of the produced liquid products can be controlled and varied for the production of products in different qualities and quantities, and the synthesis gas produced, contains practically no tar.

The invention is illustrated by way of the following non-limitative example, wherein:

figure 1 shows an schematic view of a system according to the invention.

The exemplary embodiment of the invention shows a schematic view of an improved thermal cracking process in which the quality and quantity of gaseous, liquid and solid products from solid combustible material as biomass, waste, fossil fuel and plastics is controlled and optimised.

Biomass, waste or other combustible materials are processed in a thermal cracking process (2) and a distillation process (3), to retrieve a defined quality and quantity of gaseous and liquid products. The liquid products, when regarded as residue, are gasified for the production of synthesis gas using charred input material. By means of the system and the method according to the invention, the gasification of the gaseous and moisterous fraction from the distillation process (3) is made possible and the use of tar free synthesis gas to heat the reactors and the gasification air is made possible.

With the. mentioned combination of system components three types of liquid products can be produced. The first and main liquid product is the liquid fraction, from the distillation process of the thermal cracking process (2) . The liquid fraction is a mixture of

hydrocarbons formed by the thermal cracking process (2) with condensation temperatures of typical minimal 110 °C to a maximum of 400 °C. The liquid fraction can be used as a boiler or transportation fuel. The second liquid product is the heavy liquid fraction from the distillation process. This fraction is separated in the distillation process (3) with a condensation temperature of typically 300 °C to 600 °C, preferably between 350 and 400 °C. This liquid contains dust particles and has a high viscosity. This fraction can be returned to the thermal cracking process (2), or can be tapped of to use as a heavy bunker fuel or for the

extraction of specific chemicals. The third fraction is a mixture of hydrocarbons that are formed by heating unstable char in the saturator (4) to typically 500 °C to 800 °C, preferably 600 °C. This fraction can be described as a tar. It can be fed to the gasifier (5) or tapped of for

extraction of specific chemicals. The solid product the mentioned combination could make if desired is the charred feedstock, further referred to as char. The char is formed in the thermal cracking process (2) and heated in the saturator (4) typically between 500 °C to 800 °C, preferably 600 °C, and consists of carbon and possible non-organic material as for example metals and stone, depending on the feedstock.

The input of the process are all combustible materials that can be thermally cracked, such as biomass, waste and plastics. If necessary the materials are dried in the storage and drier (1) before they are fed to the thermal cracking process (2) .

The material is fed into a thermal cracking process, where it is heated in absence of air or any source of oxygen, to a temperature between 200 °C and 700 °C in one or two phases. The thermal cracking process operates in combination with a distillation process (3) .

The products that are formed are a mixture of gasses, at ambient temperature, a liquid fraction and charred solid input material. The gasses and liquid products that are in vapour state in the thermal cracking process (2) are directly fed to a _. distillatio process (3) with a typical hold up time of 1 to 10 seconds and

preferably 2 seconds.

The distillation process (3) separates by the difference in condensation temperatures the products obtained by thermal cracking in three fractions, a gaseous fraction, a light liquid fraction and a heavy liquid fraction. The gaseous fraction has a condensation

temperature between ambient to 150 °C, preferable 110 °C. The liquid fraction consists of hydrocarbons with a boiling temperature typical between 150 °C and 350 °C. The properties of this liquid are sufficient as a ^' (half-) product as a boiler or transportation fuel. The heavy liquid fraction is separated in the distillation process (3) with a condensation temperature of typically 300 °C to 600 °G, preferably between 350 and 400 °C. By leading this heavy liquid fraction into the thermal cracking process (2), the residence time of this fraction is increased, allowing further disintegration of the heavier organic molecules .

The thermal cracking process (2) is heated by a coil in which synthesis gas flows with a temperature of 500 °C.

If desired, the heavy liquid fraction from the distillation process (3) can be tapped of for the

application of a heavy bunker fuel or for the extraction of chemicals .

If desired, the charred output can be extracted for different applications as products or half products for other processes.

From the thermal cracking process (2) the char is transported to the saturator (4). The saturator (4), combined with the gasifier and the chemical quench (6), transforms the char with the heavy fraction from the saturator (4) in practical tar free synthesis gas. In the saturator (4) the heavy fraction with a high condensing temperature is removed from the charred material. The heavy liquid fraction is regarded as tar that could cause clogging of the synthesis gas for example pipes and engines. The heavy Liquid fraction is gasified with the gaseous products from the distillation process of the thermal cracking process (2) at a temperature of typically 1200 °C to 1400 °C. The char form the saturator (4) is transported to the chemical quench (6), where it is gasified by the synthesis gas from the gasifier. In the chemical quench (6) the carbon dioxide and water in the synthesis gas react with the carbon of the char, forming carbon monoxide and hydrogen. This reaction is endothermic. The temperature of the synthesis gas therefore decreases from a temperature of typically 1200 °C to 1400 °C to a temperature typically 500 °C to 800 °C, preferably 600 °C, depending on the choice of operation. Because the treated char does not release liquid hydrocarbons, the synthesis gas practically does not contain any tar. The char is reduced to ashes and discharged from the vessel of the chemical quench (6) via a water lock.

The heavy liquid fraction from the saturator (4) can, however, also be sent to the thermal cracking process (2) in order to achieve further residence time. The hydrocarbons of the heavy fraction from the saturator (4) disintegrates into lighter fractions. These lighter fractions are then separated in the distillation into a gaseous fraction, a liquid fraction and a heavy liquid fraction. If desired, this heavy liquid fraction can also be tapped of for the extraction of chemicals.

The gaseous fraction is a mixture of substances with a condensation temperature between ambient to 150 °C, preferable 110 °C. The gaseous fraction contains water vapour and is in many cases therefore not suitable as a fuel for gas engines. The gaseous fraction is therefore fed to the gasifier with the heavy liquid fraction from the saturator (4) .

The synthesis gas from the chemical quench (6) has a temperature of typically 500 °C to 800 °C, preferably 600 °C. This synthesis gas practically does not contain any heavy liquid fraction that as a tar could cause problems as for example clogging pipes and tubes as in for example the heating coils (8) . The synthesis gas is lead as a heating gas through coils in firstly the saturator (4) and secondly the thermal cracking process (2), before the synthesis gas preheats the air for the gasifier (5) . This invention is preferably characterised by using the hydrogen rich gas for transportation of instable hydrocarbons and acidulous hydrocarbons. With hydrogen rich gas as a drive gas these instable hydrocarbons and

acidulous hydrocarbons are converted, mostly into desired hydrocarbons hence stimulating the yield of the

installation.

In this invention is preferably characterised by the use of the produced synthesis gas to preheat the air (7) for gasification.

The above described process can be operated as a batch operation, using only one reactor for the thermal cracking of the in feed material, condensing the liquid fraction with a high condensing temperature from the char as in the saturator, followed b the gasification of this char by synthesis gas, air or oxygen. The vapours from the thermal cracking in the batch reactor can be sent to an external distillation process for the separation in a gaseous fraction, a liquid fraction and a tar fraction. The tar fraction can be sent back to the batch reactor that is in a stage of thermal cracking. The heavy tar can be gasified externally or, if desired, tapped of for the thermal cracking in a new batch or for applications as bunker fuels or the extraction of chemicals. The hot tarless synthesis gas f om the gasification of the char can be used the preheat gasification air or heat other batch reactors operating this process.

The invention is preferably characterised by the use of a thermal cracking process (2) and a method of tar free synthesis gas production, in order co obtain and controlled and optimised process of gaseous, liquid and solid products from solid combustible material as for example coal, biomass, waste and plastics, wherein the cracking process preferably comprises one or multiple aspects of the following aspects:

• gasifying the gaseous fraction from the thermal cracking process (2) . and distillation process (3), in the gasifier.

sending the heavy liquid fraction from the saturator (4) to the thermal cracking process (2) for further disintegration. The products of the thermal cracking of heavy liquid fraction are then separated by the

distillation process (3) into a gaseous fraction and the desired light liquid fraction.

• heating of the three closed vessels; the thermal cracking process (2), the saturator (4) and the chemical quench (6) , by coils through which heated synthesis gas flows. This is possible because a synthesis gas is produced by the process that does not contain any hydrocarbons that will condense at temperatures typically lower than 150 °C.

• preheating of the air for the gasification (7), by indirect heating of the synthesis gas.

· creating a hydrogen rich atmosphere, in order to convert instable hydrocarbons and acidulous hydrocarbons, mostly into desired hydrocarbons hence stimulating the yield of the installation.

The invention is preferably characterised by the possibility of operating the process as a batch process using only one reactor for the thermal cracking of the in feed material, condensing the liquid fraction with a high condensing temperature from the char as in the saturator, followed by the gasification of this char by synthesis gas, air or oxygen. The vapours from the batch operation can be sent to any distillation process. Any tar fractions from this batch process can be tapped of for the thermal cracking in a new batch or for applications as bunker fuels or the extraction of chemicals. The hot tarless synthesis gas from the gasification of the char can be used the preheat gasification air or heat other batch reactors operating this process.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. Use of the verb "comprise" and its conjugations does not exclude the presence of elements or steps other than those stated in a claim. The article "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.