EP2265696A2

EP2265696A2 - Method and device for converting carbonaceous raw materials

Info

Publication number: EP2265696A2
Application number: EP09713765A
Authority: EP
Inventors: Helmut Kammerloher; Sven Johannssen; Dragan Stevanovic
Original assignee: Krones AG
Current assignee: Krones AG
Priority date: 2008-02-28
Filing date: 2009-02-28
Publication date: 2010-12-29
Also published as: CN101970617B; EA201070910A1; BRPI0907997A2; UA104719C2; WO2009106357A2; WO2009106357A3; JP5777887B2; NZ587568A; US20110035990A1; CA2716387A1; JP2011514923A; CN101970617A; EA020334B1; AU2009218694B2; AU2009218694A1

Abstract

The invention relates to a method and a device (35) for converting carbonaceous raw materials and in particular biomass into fuels. In this method, firstly an allothermic gasification of the raw materials is performed in a gasifier (1) using heated water steam (3). After purification of the synthesis gas produced during the gasification and cooling of the synthesis gas, the synthesis gas is converted into a liquid fuel using a catalyzed chemical reaction. According to the invention, the heated water steam is used both as a gasification agent and also as a heat carrier for the gasification and has a temperature which is greater than 1000°C.

Description

Process and apparatus for converting carbonaceous

raw materials

description

The invention relates to a method and an apparatus for converting carbonaceous raw materials into preferably liquid fuels. The invention will be described with reference to biomass, but it should be understood that the method and apparatus of the present invention may be used with other carbonaceous products. The invention is particularly concerned with the production of BtL fuels (biomass to liquid). This term refers to fuels that are synthesized from biomass. In contrast to biodiesel BtL fuel is generally obtained from solid biomass, such as firewood, straw, biowaste, animal meal or reeds, ie made of cellulose or hemicellulose and not only from vegetable oil or oilseeds.

The great advantages of this synthetic biofuel are • its high biomass and area yields, which are up to 4000 1 per hectare, without any competition with food. In addition, this fuel has a high CO ₂ ~ reduction potential of over 90% and its high quality is subject to no use restrictions in today's and foreseeable engine generations.

Usually, in the production of BtL fuels in a first process step, a gasification of biomass is carried out and a subsequent generation of Synthesis gas. This is synthesized at elevated pressure and elevated temperature to the liquid fuel.

By fuels are meant those substances which can be used as fuels for internal combustion engines, in particular but not exclusively methanol, methane, gasoline, diesel, paraffin, hydrogen and the like. Preferably, liquid fuels are generated under ambient conditions.

From the state of the art so-called autothermal processes are known in which air or oxygen is used as the gasification agent, so that the necessary gasification energy is generated by the incomplete combustion of raw material. These methods are relatively simple, but have the disadvantage that in this case a higher proportion of carbon dioxide in the product gas is formed.

A portion of the imported raw material is used as fuel and is therefore no longer for the

Synthesis gas production available. Furthermore, when using air as a gasification agent, the synthesis gas produced on a high proportion of nitrogen, which in turn is the calorific value is lowered.

Various carburetors are known from the prior art, such as autothermal fixed bed gasifier or autothermal Flugstromvergaser (see SunDiesel - made by Choren - experience and latest developments, Matthias Rudioff in "Synthetic Biofuels", series "renewable resources" Volume 25, Agricultural Publishing GmbH , Münster 2005). In so-called allothermal process the necessary gasification energy is supplied from the outside, so that the carburetor itself no additional amount of CO ₂ is produced and thus no loss of the input material as fuel for energy production occurs. Therefore, it is also possible to use water vapor as a gasifying agent (for the endothermic reaction). This leads to a higher concentration of hydrogen (H ₂ ) in the synthesis gas. If the synthesis gas is used for the production of the liquid fuels (for example in the context of a Fischer-Tropsch synthesis), this is advantageous.

For example, fluidized-bed gasifiers according to the "casting principle" are known from the prior art. The necessary gasification energy is applied by supplying hot sand (at a temperature of 950 ^° C.). The preheating of this sand is in turn generated by the combustion of raw material used (in this case, biomass). Thus, the valuable raw material is used as an energy source, which reduces the specific yield.

Furthermore, the known from the prior art gasification processes are not or only poorly combined with a so-called Fischer-Tropsch synthesis. Although it was attempted known from the prior art gasification process with a system for the

Liquid fuel synthesis (such as Fischer-Tropsch reactor) to combine. As a result, however, only methods have been achieved which have very poor or moderate efficiencies for the production of liquid fuels. In elaborate studies it could be determined that the Fischer-Tropsch synthesis a certain Synthesis gas composition requires (a ratio between H ₂ and CO which is> 2). An increase in this ratio could previously be generated by a so-called. Shift reaction: CO + H ₂ O => CO ₂ + H ₂ ).

In the course of the development of new, in particular regenerative, fuels, different methods for their production have recently become known.

From DE 195 17 337 C2, a biomass gasification process and an apparatus therefor are known. In this case, two electrodes supplied by a power source are provided in a reaction chamber, wherein an arc is generated between these electrodes.

DE 102 27 074 A1 describes a process for the gasification of biomass and a plant for this purpose. In this case, the substances are burned in a gas-tightly separated from a gasification reactor combustion chamber and introduced the heat energy from the combustion chamber in the gasification reactor.

DE 198 36 428 C2 describes methods and devices for gasification of biomass, in particular of wood pulp. Here, a Festbettentgasung in a first gasification stage is effected at temperatures up to 600 ⁰ C and in a subsequent second gasification stage a fluidized bed gasification at temperatures between 800 ° C and 1000 ⁰ C.

From DE 10 2005 006305 Al a process for the production of combustion and synthesis gases with high-pressure steam generation is known. In this process, gasification processes in an air flow gasifier used at temperatures below 1200 ⁰ C.

From WO 2006/043112 a method and a plant for the treatment of biomass are known. In this case, temperatures of water vapor between 800 ⁰ C and 95O ⁰ C are used for gasification. For gasification, the principle of fluidized bed gasification is used. However, this method is not useful for the gasification of low ash melting raw materials, such as many varieties of biomass, straw and the like. Furthermore, the steam temperatures described therein in the range of 800 ⁰ C to 950 ⁰ C are not sufficient to ensure a completely allothermal gasification. Therefore, it is necessary to always mix in a certain amount of air, which in turn results in problems with carbon dioxide and nitrogen contents in the synthesis gas.

For heating the water vapor, a recuperative heat exchanger is used in the case of WO 2006/043112 A1. These heat exchangers have the disadvantage that they are very expensive and their maintenance is very complicated and expensive. Furthermore, this process does not use the significant waste heat from the Fischer-Tropsch reactor, which arises during the synthesis process.

The present invention is therefore based on the object to provide a method and an apparatus for the gasification of carbonaceous raw materials available, which allows high efficiency and high efficiency. Furthermore, a method is to be created, which in turn supplies resulting energies to the process. More specifically, a gasification process is to be specified, which allows efficient conversion of the raw material and at the same time a particularly suitable ratio between hydrogen and carbon monoxide in the synthesis gas. In addition, the device according to the invention should also be suitable overall for smaller capacities and a possible decentralized operation with different starting materials in order to achieve a good economy. This is achieved by a method according to claim 1 and an apparatus according to claim 12. Advantageous embodiments and further developments are the subject of the dependent claims.

In a method according to the invention for the conversion of carbonaceous products and in particular biomass into liquid fuels, the carbonaceous raw materials are gasified in a gasifier in a first step, wherein heated steam is introduced into the gasifier. In a further step, the synthesis gas produced during the gasification is purified and, in a further step, preferably its temperature is changed. Preferably, the synthesis gas is cooled. Finally, the synthesis gas is converted to a liquid fuel by means of a catalyzed chemical reaction, preferably using a Fischer-Tropsch reactor for this conversion. According to the gasification is a completely allothermal gasification and the heated water vapor serves both as a gasification agent and as a heat carrier for the gasification and has a temperature which is above 1000 ⁰ C. Under an allothermal gasification is understood that the heat input comes from the outside. Thus, the method according to the invention is divided into at least 3 process steps, wherein first an allothermic gasification of the raw material (such as biomass and straw in particular) with water vapor, which serves as a gasification agent and energy carrier is made. In the subsequent cleaning process, a cleaning of the gas, in particular of dust and tar, and preferably a subsequent recycling of these substances in the gasification process is performed. As part of the preferred Fischer-Tropsch synethesis synthesis gas is converted into liquid fuels.

In order to achieve a complete allothermal gasification according to the invention, it is necessary for the steam used to have a temperature which is significantly above the average gasification temperature. Therefore, temperatures of at least 1000 ⁰ C are used, but preferably temperatures of more than 1200 ⁰ C and more preferably of more than 1400 ⁰ C.

By using the highly superheated steam as a gasification agent and energy source to achieve a high water vapor excess in the carburetor. This excess is preferably always above 2, more preferably above 3. By this excess steam is achieved on the one hand, the formation of tar is reduced and on the other hand, the tars are clearly kurzkettiger and thus less viscous than in the case of gasification without excess steam.

Furthermore, the ratio between hydrogen and carbon monoxide (H ₂ / CO) is at least equal to or greater than 2, which is particularly advantageous for the downstream Fischer Tropsch synthesis is. Finally, the high concentration of water vapor in the product gas also allows destruction of residual tars in a preferably downstream thermal cracker. More specifically, this destruction is easier to perform in an atmosphere with higher vapor content.

By means of the recuperative heat exchangers used in the prior art, it has hitherto not been possible to achieve such steam temperatures. However, bulk generators can be used, as described, for example, in EP 0 620 909 B1 or DE

42 36 619 C2 have been described. The disclosure of EP 0 620 909 B1 and DE 4 236 619 C2 are hereby incorporated by reference in their entirety into the disclosure herein. The use of such bulk regenerators leads to a device which is more efficient than the prior art.

In a preferred process, a synthesis gas having a particularly high H ₂ / CO ratio, more specifically a ratio greater than 2, is formed.

In a further preferred method, another gaseous medium is fed to the gasifier together with the steam. Preferably, these are oxygen or air, which are heated together with the steam to the temperature of the steam and fed to the gasifier.

In a further preferred method, the highest temperature within the carburetor is always above the Ash melting point. In this way it can be achieved that ash is discharged in the liquid state.

The gasifier is preferably a fixed bed countercurrent gasifier. In principle, different types of carburetors according to the prior art can be used. However, the particular advantage of a countercurrent fixed bed gasifier is that within this reactor individual zones are formed in which different temperatures and thus different processes occur. The different temperatures are based on the fact that the respective processes are strongly endothermic and the heat only comes from below. In this way, the very high steam temperatures are utilized in a particularly advantageous manner. Since the highest steam temperatures prevail in the entry zone of the gasification agent, it is possible to always produce the conditions for a liquid ash discharge.

This is particularly advantageous in biomass gasification because there the ash melting points deviate very much depending on the fuel grade and the soil properties.

In the prior art, it has not been possible to implement different fuels with a certain type of carburettor and thus to adapt to the market situation. Due to the high temperatures, however, it is fundamentally possible according to the invention to design the process so that the resulting ash is always discharged in liquid form. In cases where the ash melting point is particularly high, a predetermined amount of flux may preferably be added to the fuel. By the above-described simultaneous supply of oxygen or air, a further temperature increase can be achieved in the ash discharge zone.

The purification of the synthesis gas preferably takes place by means of a cyclone and preferably by means of a multicyclone. In this case, tars and dust can be separated and preferably recycled back into the carburetor.

Since the pyrolysis gases do not flow through any other hot zones, the tar content in the product gas is relatively high. This tar should not get into the reactor for the Fischer-Tropsch synthesis, since the tar is harmful for the catalysts used there. Furthermore, the energy content of the tar is high and consequently has a negative impact on process efficiency. Therefore, the tar, together with the accumulated dust, is preferably pushed off immediately after the gasifier in a cyclone and particularly preferably in a multicyclone and further injected with a suitable pump into the high-temperature zone of the gasifier. A cyclone is a centrifugal separator in which the substance to be deposited is fed tangentially in a vertical cylinder which tapers conically downwards and is thus set into a rotational movement. By acting on the dust particles centrifugal force they are thrown to the outer wall, thereby braked and sink into the underlying Staubabscheideraum.

Preferably, remaining tars are broken up into short-chain molecular structures after the purification process. In this case, a thermal cracker is particularly preferably used, which by very high temperatures, more preferably between 800 ⁰ C and 1400 ⁰ C and preferably by the supply of a small amount of oxygen or air, the remaining tek in breaks short-chain molecular structures. In this so-called thermal cracking, the synthesis gas is thus brought to a very high temperature, whereby the long-chain molecular structures are broken. At the same time, this process removes the remaining amount of dust.

Thus, the cleaning in the cyclone represents a first cleaning step and the cleaning in the cracker a second cleaning step.

In this case, a part of the superheated gasification agent, that is to say the water vapor, is additionally preferably fed through a line to the described cracker. Thus, the gasification agent is used in addition to the thermal cracking.

In a further preferred method, the synthesis gas is cooled in a gas cooler and preferably subsequently in a condenser, wherein excess water vapor is condensed out, which can be used for heat recovery. This reduces the amount of syngas and at the same time increases the proportions of the two most important components, namely CO and H ₂ . In the condenser, the residual amounts of pollutants such as dust and tars are washed out. If necessary, it is possible to finally remove residual amounts of pollutants (which are in the ppm range), for example by using a scrubber with ZnO as catalyst.

In another method, the synthesis gas is freed from dust by means of a cyclone, so that the tars remain in the synthesis gas. This is by electrical Heat tracing ensures that the pipes and the cyclone stretch to temperatures above the

Condensation temperature of the tars are kept. The tars are removed in a condenser together with the water from the synthesis gas. This "tar water" forms a pumpable suspension which is vaporized, superheated and returned to the gasification process.

Thus, the synthesis gas is preferably prepared in a CO ₂ scrubber and in a heat exchanger for optimum composition and temperature for the subsequent Fischer-Tropsch synthesis. The CÜ ₂ amount in the synthesis gas is reduced in the mentioned CO ₂ scrubber or in a PSA (Pressure Swing Absorption) / VSA (Vacuum Swing Absorption) system with molecular sieving technology to provide optimum conditions for Fischer-Tropsch synthesis and efficient energy utilization to ensure the overall system. Preferably, in a gas preheater, the synthesis gas is preheated to an ideal temperature for the Fischer-Tropsch synthesis.

The waste heat from at least one gasification-following process is preferably used for saturated steam generation. It is possible, for example, to use the waste heat from the gas cooler described for the preheating of the water for saturated steam generation. Furthermore, the heat generated in the Fischer-Tropsch reactor itself waste heat can be used for the production of saturated steam. The exothermic synthesis reaction in the Fischer-Tropsch reactor requires constant and uniform cooling. Preference is given to cooling with boiling water and subsequent

Saturated steam generation. In addition to the liquid fuel produced as by-products, a so-called. Off-gas, which consists of unreacted Synthesis gas and gaseous synthesis products, a water condensate and saturated steam because of the above-described cooling. In order to achieve a process with very high energy efficiency, all waste energy streams or as many as possible thereof are particularly preferably fed into the gasification reactor. Thus, for the production of superheated steam as a gasifying agent, the energy from the gas cooler for water preheating, the waste heat from the cooling of the Fischer-Tropsch reactor for saturated steam generation and the chemically bonded energy of the off-gas for the superheated steam combustion in bulk reactors.

In this way, the resulting waste energy flows from the gas cooler and the Fischer-Tropsch reactor can be fed back into the gasifier in the form of superheated steam, which allows an increase in efficiency over the prior art.

In a further preferred method, a predetermined part of synthesis gas formed is fed to an offgas generated in the synthesis. Preferably, a bypass line is used, which is connected to the Fischer-Tropsch reactor.

In another method, it is also possible to use an excess saturated steam amount for an external or internal heat consumer. Also it would be possible the heat of the flue gas that is described from the

Bulk regenerators emerges to use by means of a heat exchanger for an external or internal heat consumer. In a further advantageous method, a pressure generating device is provided which increases the pressure of the synthesis gas supplied to the conversion. In this case, for example, a gas compressor may be provided, which increases the synthesis gas after the condenser to the necessary pressure for the Fischer-Tropsch reactor. Also, advantageously, the entire device can be under a pressure which is advantageous for the synthesis process in the Fischer-Tropsch reactor. In this way, the efficiency of the entire process can be increased.

In a further advantageous method, saturated steam is superheated by means of a suitable internal or external heat source and expanded in a steam turbine before it is fed to the bulk material regenerators.

More precisely, the entire system, with the exception of the Fischer-Tropsch reactor and the steam-carrying lines, can be designed without pressure and the energy required for synthesis gas compression can be obtained from the steam turbine. In this way, the investment costs can be reduced while maintaining efficiency.

In a further advantageous method, condensate obtained in the conversion is used as additional liquid to the condensate from the condenser for the production of saturated steam. In this way, a closed water cycle is made available.

In a further method according to the invention, the heated water vapor is used both as a gasification agent and as a heat carrier for the gasification, and has a temperature which is above 1000 ⁰ C. In addition, the Carburetor separated from the heated water vapor fed to another gaseous medium. Advantageously, the further gaseous medium to a temperature which is below 600 ⁰ C, preferably below 400 ⁰ C and more preferably below 300 ⁰ C. It would also be possible to provide room temperature. In a further advantageous method, the gasification is an allothermic gasification. Due to the separate supply of air and water vapor can be achieved that the air, which preferably does not contribute to the actual gasification process, does not need to be heated with, so that the overall energy efficiency of the process can be increased.

In this further method according to the invention thus little heated air or oxygen in the reactor, separated from the heated water vapor, introduced. These air / oxygen additions are used to adjust the gas composition, and not to the energy supply, as this is due to the superheated steam (allothermic gasification). With the addition of air / oxygen, the proportions of hydrogen (H ₂ ) and carbon monoxide (CO) in the product gas can be influenced. For the Fischer Tropsch synthesis, it is advantageous to set an H ₂ / CO ratio of -2.15 to 1. Furthermore, the addition of air / oxygen has an effect on the gasification temperature and and the CO ₂ and CH ₄ contents in the product gas.

The present invention is further directed to an apparatus for converting carbonaceous raw materials and in particular biomass into liquid fuels, which apparatus comprises a gasifier in which carbonaceous raw materials are gasified by means of heated steam, at least one cleaning unit used to purify gasification synthesis gas is used, at least one temperature change unit for changing the temperature of the resulting synthesis gas and a conversion unit for converting the synthesis gas into liquid fuel. According to the invention, the device has at least one heating device which heats the steam to a temperature which is above 1000 ° C. The temperature change unit is preferably a cooling unit.

Preferably, the purification unit is a cyclone and more preferably a multicyclone.

In a further advantageous embodiment, the device has a further cleaning unit which treats residual tars. In particular, these are not exclusively the cracker described above.

In a further advantageous embodiment, two cooling devices are provided in the form of a gas cooler and a condenser downstream of this gas cooler.

In a further advantageous embodiment, the device has a conveying device, which is arranged between the cleaning unit and the carburetor and promotes a product resulting from the cleaning process, and in particular tar, into the carburetor.

In a further advantageous embodiment, at least two heating devices are provided, wherein at least two of these heating devices are operated in antiphase. In this way, a continuous heating process for the gasification agent can be achieved. The present invention is further directed to a method of the type described above, wherein an apparatus of the type described above is used to carry out the method.

Further advantages and embodiments will be apparent from the attached drawings:

Show:

Fig. 1 is a schematic representation of a device according to the invention;

FIG. 2 is a detailed view of the device of FIG. 1 for illustrating the heating of the water vapor; FIG.

FIG. 3 shows a further detailed illustration of the device from FIG. 1 for illustrating the purification of the synthesis gas; FIG.

4 shows a further detailed illustration of the device from FIG. 1 in a further embodiment;

FIG. 5 shows a further detailed illustration of the device from FIG. 1 in a further embodiment; FIG.

Fig. 6 is an alternative flow sheet diagram with a

Condensing the tars and water from the syngas and using the regenerators as steam superheaters and crackers of the tars produced during gasification; and Fig. 7 shows an alternative flow diagram with an air / oxygen addition after overheating of the water vapor.

1 shows a schematic representation of a device 35 according to the invention for the conversion of carbonaceous raw materials into synthesis gas and for the subsequent liquid fuel synthesis. In this case, the reference numeral 1 refers to a fixed bed countercurrent reactor. The raw material 2 is introduced from above into the reactor 1 and the gasification agent 3 along a feed line 42 from below. In this way it is achieved that the gasification agent 3 and the synthesis gas produced flow through the reaction space in the opposite direction to the Brennstoffström. The resulting ash in the carburetor 1 is discharged downwards, that is, along the arrow P2.

Starting from the reactor 1, the synthesis gas passes via a line 44 into a cyclone or preferably a multicyclone. In this cyclone 4 a large part of the tar and the resulting dust is eliminated and injected with a pump 5 back into the high temperature zone of the carburetor 1. The pre-cleaned in this manner the synthesis gas in which Restteer is present together with residual quantities of dust passes via a further conduit 46 into a thermal cracker 6. In this thermal cracker Restteer with the amount of dust at maximum temperatures between 800 ⁰ is C and 1400 ⁰ C destroyed. Optionally, in order to obtain the necessary temperature, a predetermined amount of oxygen and / or air can be injected directly into the high-temperature zone and in this way a partial oxidation of the tars can be achieved (see arrow P1). After the thermal cracker, the synthesis gas passes via a line 48 into a gas cooler 7. In this gas cooler, the synthesis gas is cooled so far that 8 excess water vapor is condensed out in the downstream condenser. Optionally, the amount of CO ₂ in the synthesis gas can be reduced by means of a CO ₂ scrubber 9 or a PSA / VSA plant with molecular sieve technology. In addition, residual amounts of pollutants (which are in the ppm range) can be completely removed, for example with the aid of a scrubber (not shown) with ZnO. The reference numeral 10 refers to a gas preheater in which the synthesis gas is preheated to a suitable temperature for the subsequent Fischer-Tropsch synthesis taking place.

The reference numeral 11 refers to a Fischer-Tropsch reactor in which from the synthesis gas under suitable thermodynamic conditions, that is, under appropriate pressure and temperature of the synthetic liquid fuel 12, z. B. BtL is generated in the case of biomass gasification. By-products of this synthesis are saturated steam 14 by cooling the reactor 13 and an off-gas 15 consisting of unreacted synthesis gas and gaseous synthesis products. In addition, there is also a water condensate 16. This water condensate 16 can be drained via a valve 52.

The saturated steam 14 then passes through a connecting line 50, which is split into two sub-lines 50a and 50b, in two bulk regenerators 17 and 18. In these bulk regenerators, the water vapor is superheated to the required temperature. In the apparatus shown in Fig. 1 are two bulk regenerators 17, 18th provided, which allow continuous operation of the system. While in the bulk regenerator 17, the water vapor is superheated, the bulk material regenerator 18 is in a heating phase, that is, it is here in particular by the combustion of off-gas 15, which is supplied to it via a connecting line 54 from the Fischer-Tropsch reactor 11 charged with heat energy. To control the two bulk regenerators, a plurality of valves 62 to 69 is used. The valves 62, 63, 66 and 68 are assigned to the bulk material regenerator 17 and the valves 64, 65, 67 and 69 to the bulk material regenerator 18.

The respective resulting combustion gases leave the plant through a chimney 19. By the periodic switching of the valves shown 62 - 69, the two bulk regenerators 17 and 18 are operated alternately. It is also possible to generate the necessary steam from the condensate, which originates from the condenser 8. Depending on the water content of the raw material 2, it is possible to use additional amounts of water, for example the condensate 16 from the Fischer-Tropsch reactor. Since the required amount of water is conveyed through the gas cooler 7 with the aid of the pump 20, preheating also takes place in this respect.

In the cooler 13 of the Fischer-Tropsch generator 11 saturated steam 14 is also generated, which in turn is overheated in the bulk regenerators 17 and 18, in which case the chemical energy from the off-gas 15 can be used. In this way, the superheated steam 3 becomes the total waste energy generated in the process supplied and so the water vapor can be heated particularly advantageous.

Instead of the two bulk material regenerators 17, 18 shown in FIG. 1, three or more can also be used

Bulk regenerators are used to achieve a particularly smooth operation.

FIG. 2 shows a detailed illustration of a further embodiment of the device shown in FIG. 1. In addition, oxygen and / or air is introduced here along the arrow P3. In this way, the oxygen can also be referred to as pebble hoppers

Bulk material regenerators 17 and 18 are overheated together with the steam to a very high temperature. It is possible, even with a relatively small amount of less than 10 vol.% Oxygen or air in the highly superheated gasification agent to significantly increase the temperature in the ash melting zone, to get in this way a low-viscosity ash. In addition, this measure, that is, the supply of air or oxygen, further increase the utilization of carbon and positively influence the tar formation by increasing the raw gas temperature.

Fig. 3 shows a further preferred embodiment of a device according to the invention. Here, a line 30 is additionally provided, via which gasification agent can be injected into the cracker 6. This measure is particularly effective if the necessary temperature in the cracker 6 is well below the gasification agent temperature and if the gasification agent has a certain proportion of oxygen or air (see Fig. 2). With a Hot gas control valve 21, the einzudüsende amount can be regulated.

4 shows a further detailed representation of a preferred embodiment. In this case, a further line 22 and a further control valve 23 is provided. If the amount of off-gas 15 for the heating of the gasification agent 3 in the bulk regenerators 17 and 18 is insufficient, an additional amount of synthesis gas, for example after the condenser 8, can be supplied through the bypass line 22 via this line.

Fig. 5 shows a further detailed representation of a preferred embodiment. If the saturated steam quantity 14 from the cooling of the Fischer-Tropsch reactor 11 is greater than the necessary amount of steam for the gasification reactor 1, the excess amount of saturated steam can be passed to an external or internal heat consumer 24 (for example a drying plant). In this way, the process efficiency can be further increased. The excess saturated steam quantity is also set here by a control valve 25.

Fig. 6 illustrates an alternative to tar purification and removal from the product gas. In the cyclone 4, the product gas is freed of dust. In a condenser 8, the water and the tars are condensed out at a temperature of 50 ⁰ C. In order to prevent the tars from condensing prematurely, the pipes between the carburetor and the condenser are heated above 200 ^° C., particularly advantageously above 300 ^° C. It forms a tar / water mixture. The tar water is optionally mixed with water and conveyed by means of the pump 20 and to a working pressure of> 1 bar, advantageously to 10 bar and particularly advantageous Brought 30 bar. Subsequently, this is vaporized by the resulting heat of the Fischer-Tropsch synthesis 13 and passed through the pipe 14 to the regenerators 17 and 18. In the regenerators, the steam, as already described, overheated and the tars cracked. Via the pipe 3, the water vapor and the gases of the cracked tar get into the carburetor. The advantage of this method is the fact that it can be dispensed with otherwise necessary parts of the system.

Fig. 7 illustrates an alternative to the gasification process in which water vapor, additionally little heated air or pure oxygen is added to the actual gasification agent in the reactor. This is done to adjust the gas composition of the product gas. In this case, this air is supplied via a further supply line 71 to the carburetor.

All disclosed in the application documents features are claimed as essential to the invention, provided they are new individually or in combination over the prior art.

Claims

claims

1. A process for the conversion of carbonaceous

Raw materials and in particular of biomass in fuels with the steps:

- gasification of the carbonaceous raw materials (2) in a gasifier (1) wherein heated water vapor (3) is introduced into the gasifier (1) and used for gasification;

- Purification of the gas produced during the gasification syngas;

- Temperature change of the synthesis gas

Conversion of the synthesis gas into a liquid fuel by means of a catalyzed chemical reaction, preference being given to using a Fischer-Tropsch reactor (11), characterized in that the gasification is an allothermic gasification and the heated water vapor (3) both as a gasification agent is also used as a heat transfer medium for the gasification and has a temperature which is above 1000 ⁰ C.

2. Method according to claim 1, wherein a further gaseous medium is supplied to the gasifier (1) together with the water vapor (3).

3. The method according to at least one of the preceding claims, characterized in that the carburetor (1) a fixed bed - countercurrent - carburetor (1).

4. Method according to at least one of the preceding claims, characterized in that the working temperature in the gasifier (1) is always above the ash melting point.

5. The process according to claim 1, wherein the purification of the synthesis gas is carried out by means of a cyclone (4) and preferably by means of a multicyclone (4).

6. Method according to at least one of the preceding claims, characterized in that, after the purification process, the molecular structures of tars still present are broken up into short-chain molecular structures.

7. The method according to claim 1, wherein the waste heat from at least one of the processes following the gasification is used for saturated steam generation.

8. The method according to at least one of the preceding claims, characterized in that a predetermined part of resulting synthesis gas a in the synthesis resulting exhaust gas (15) is supplied.

9. The method according to claim 1, wherein a pressure-generating device is provided, which increases the pressure of the synthesis gas supplied to the conversion.

10. A method according to at least one of the preceding claims, characterized in that saturated steam (14) is overheated by means of a heat source and expanded in a steam turbine before it is fed to bulk material regenerators (17, 18).

11. The method according to claim 1, wherein the condensate obtained during the conversion is used as additional liquid to the condensate from the condenser for generating the saturated steam.

12. The method according to at least one of the preceding claims, characterized in that the resulting tars and the dust are mostly together in a cyclone, particularly advantageous in a multi-cyclone (4), deposited and (alternatively to claim 5) in the bulk regenerators (17 & 18 ) are burned.

13. Method according to at least one of the preceding claims, characterized in that the pipes (20 & 21) and the cyclone (4) are heated.

14. The method according to at least one of the preceding claims, characterized in that the capacitor (8) is used for the separation of water and tar.

15. Method according to at least one of the preceding claims, wherein the high temperatures of the bulk material regenerators (17 & 18) are also used for cracking the tars produced during the gasification in addition to the steam overheating.

16. Process for the conversion of carbonaceous raw materials and in particular of biomass into fuels with the steps:

- Purification of the gas produced during the gasification syngas;

- Temperature change of the synthesis gas

Conversion of the synthesis gas into a liquid fuel by means of a catalyzed chemical reaction, preference being given to a Fischer-Tropsch reactor for this conversion (11) is used, characterized in that the heated water vapor (3) is used both as a gasifying agent and as a heat carrier for the gasification and has a temperature which is above 1000 ⁰ C and the gasifier separated from the heated water vapor (3) additional gaseous medium is supplied.

17. The method according to claim 16, characterized in that the further gaseous medium has a temperature which is below 600 ⁰ C, and preferably below 400 ⁰ C.

18. The process according to claim 16, wherein the gasification is an all-gasification.

19. Device (35) for converting carbonaceous raw materials and in particular of biomass into liquid fuels, with a gasifier (1) in which the carbonaceous raw materials are gasified by means of heated steam, at least one cleaning unit (4,6) for the purification of the gasification synthesis gas, at least one temperature change unit (7, 8, 10) for changing the temperature of the resulting synthesis gas and a conversion unit (11) for converting the synthesis gas into a liquid fuel, characterized in that the device (25) at least one heating device (17, 18 ), which heats the water vapor to a temperature which exceeds 1000 ⁰ C lies.

20. Device (35) according to claim 19, wherein a cleaning unit is a cyclone (4) and preferably a multicyclone (4).

21. Device (35) according to at least one of the preceding claims 19-20, characterized in that a further purification unit is provided which treats remaining terees.

22. Device (35) according to at least one of the preceding claims 19 - 21 d a d e r c h e c e n e c e s in which two temperature change devices are provided in the form of a gas cooler (7) and a condenser (8) connected downstream of said gas cooler (7).

23. Device (35) according to at least one of the preceding claims 19 - 22 characterized in that the device (35) comprises a conveying device (5) which is arranged between the cleaning unit (4) and the carburetor (1) and a in the cleaning process developing product in the carburetor (1) promotes.

24. Device (35) according to at least one of the preceding claims 19 - 23, characterized in that at least two heating devices (17, 18) are provided, wherein at least two of these heating devices (17, 18) are operated in phase opposition.

25. Device (35) according to at least one of the preceding claims 19-24 The machine has a feed line (71) in order to supply the gasifier with a gaseous medium separate from the water vapor (3).

26. Method according to at least one of the preceding claims 1-18, in which a device (35) according to at least one of claims 19-25 is used for carrying out the method.