WO2003002691A1

WO2003002691A1 - Method and device for the pyrolysis and gasification of material mixtures containing organic components

Info

Publication number: WO2003002691A1
Application number: PCT/EP2002/007078
Authority: WO
Inventors: Wolfgang Krumm; Günter Funk; Stefan Hamel; Christian Mertens
Original assignee: Herhof Umwelttechnik Gmbh
Priority date: 2001-06-27
Filing date: 2002-06-26
Publication date: 2003-01-09
Also published as: WO2003002691A8; EP1399527B1; EP1399527A2

Abstract

The invention is used for the pyrolysis and gasification of material mixtures containing organic components. The organic materials or the material mixture containing organic components are brought into contact with a heat transfer medium, preferably the ash from a combustion reactor, and pyrolysed in a pyrolysis reactor, preferably a shaft reactor. The coke which is generated by pyrolysis is combusted with an air supply in a combustion reactor, preferably in a fluidized bed reactor. The condensable components of the crude gas which is generated by pyrolysis are cracked in a cracking reactor, preferably by means of a catalyst. In order to improve said method, the heat transfer medium is transported using overheated steam (50) as a fluidizing medium.

Description

INTERNATIONAL SEARCH REPORT

Process and device for pyrolysis and gasification of mixtures containing organic components

The invention relates to a method for pyrolysis and gasification of mixtures of substances which contain organic constituents, and an apparatus for carrying out such a method.

These mixtures of substances can in particular be household waste or waste similar to household waste, as well as products which have been obtained from household waste or waste similar to household waste.

Methods and devices for pyrolysis and gasification of organic substances are already known. DE-PS 197 55 693 discloses a process for the gasification of organic substances, in which the organic substances are passed into a pyrolysis reactor in which they are kept in contact with a heat transfer medium, whereby pyrolysis takes place. The pyrolysis reactor is a moving bed reactor or a rotating drum. The pyrolysis products consist of pyrolysis gases with condensable substances and a solid carbon-containing residue. The solid carbon-containing residue and the heat transfer medium are fed to a furnace in which the carbon-containing residue is burned and the heat transfer medium is heated and fed back to the pyrolysis reactor. The tar-containing pyrolysis gases are post-processed in a second reaction zone. heated that a purified syngas with a high calorific value is obtained. This is done in such a way that the tar-containing pyrolysis gases are passed into an indirect heat exchanger in which they react with a reactant, for example water vapor. The combustion gases are passed through the indirect heat exchanger in such a way that their heat content is used for the reaction of the pyrolysis gases with the reactant. The ashes of the solid carbon-containing residues removed from the furnace and the heat transfer medium are returned to the pyrolysis reactor at the end of the entry for the organic matter.

DE-OS 199 30 071 discloses a method and a device for the pyrolysis and gasification of organic substances, in which the organic substances are introduced into a drying and pyrolysis reactor, in which they are brought into contact with the fluidized bed material of a combustion fluidized bed, whereby a Drying and pyrolysis takes place, in which the organic substances are converted into water vapor from the drying and pyrolysis products. The pyrolysis products consist of gases with condensable substances and solid carbonaceous residues. The solid carbon-containing residue, optionally with portions of the water vapor and the pyrolysis gases with condensable substances, and the fluidized bed material are fed back into the combustion fluidized bed, in which the carbon-containing residue of the organic substances is burned, the fluidized bed material is heated and fed back into the pyrolysis reactor. The water vapor from the drying and the pyrolysis gases with condensable substances are post-treated in a further reaction zone in such a way that a product gas with a high calorific value is produced. The combustion fluidized bed in which the pyrolysis residues are burned is operated as a stationary fluidized bed. The pyrolysis gases are passed into an indirect heat exchanger in which they optionally react with a reactant such as water vapor, oxygen or air or a mixture thereof. The combustion gases are brought into contact with the indirect heat exchanger in such a way that their heat content is used for the reaction of the pyrolysis gases with the reactant. In the previously known method according to DE-PS 197 55 693 and also in the method according to the older priority German patent application 199 30 071.2, an indirect heat exchanger is used, to which the heat of the combustion gases is supplied and through which the pyrolysis gases are passed. However, this procedure and the device required to carry out such a procedure have disadvantages.

The earlier priority, not prepublished German patent application 100 33 453.9 relates to a method and an apparatus for pyrolysis and gasification of mixtures of substances which contain organic constituents. The present invention is particularly well suited for use in a method and / or a device according to this German patent application. Accordingly, reference is hereby made in full to the German patent application 100 33 453.9; the content of this patent application is hereby incorporated into the present application.

In the process according to German patent application 100 33 453.9, the organic substances or the mixture of substances which contains organic constituents are brought into contact with a heat transfer medium from a combustion reactor in a pyrolysis reactor and pyrolyzed. The pyrolysis reactor is preferably a shaft reactor. A fluidized bed reactor is preferably used as the combustion reactor. The heat transfer medium is preferably formed by the ash from the combustion reactor. However, it is also possible to use another heat transfer material or fluidized bed material. The heat transfer medium or the fluidized bed material can contain ash from the combustion reactor or consist exclusively or practically exclusively of this ash. It is advantageous if the organic substances are brought into contact with the heat transfer medium by mixing them together. The organic substances and the heat transfer medium are brought into contact or mixed and dried in the pyrolysis reactor and pyro- lysed. The pyrolysis coke formed by the pyrolysis is burned in the combustion reactor or fluidized bed reactor with the supply of air.

The raw gas or its condensable constituents generated by the pyrolysis are cleaned or cracked in a cracking reactor. This cleaning or cracking is preferably carried out by means of a catalyst which is provided in the cracking reactor. This cleaning or catalytic cleaning or cracking is preferably carried out with the addition of water vapor.

The method according to German patent application 100 33 453.9 is particularly suitable for the pyrolysis and gasification of a mixture of substances which has been obtained from household waste or waste similar to household waste. This is preferably a mixture of substances which has been produced from household waste or waste similar to household waste according to the following method: if necessary, the household waste or waste similar to household waste is first pretreated, in particular comminuted. They are then composted in closed containers with forced ventilation, whereby the organic components are broken down. After a certain period of time, for example seven days - after which the biodegradable constituents are typically completely or substantially degraded - the composting is brought to a standstill by drying. The material is dried to a residual moisture of at most 15%. It can then be treated if necessary. Such a material is marketed under the name Trockenstabilat ^® .

In a pyrolysis process, in particular also in the process according to German patent application 100 33 453.9, it is generally necessary to remove the heat transfer medium, in particular hot ash, from the combustion reactor or fluidized bed reactor or fluidized bed furnace and to feed it to one or more pyrolysis reactors. It must be taken into account that neither pyrolysis gases from the pyrolysis reactors may get into the combustion reactor (fluidized bed reactor, fluidized bed furnace) nor flue gases from the Combustion reactor (fluidized bed reactor, fluidized bed furnace) may get into the pyrolysis reactor.

Mechanical conveyance of the heat transfer medium or the hot ashes with moving machine parts is not preferable due to the high temperatures or ash temperatures of 900 to 950 ° C and the abrasive behavior of the heat transfer medium or the ashes as well as the associated considerable heat losses.

In the field of circulating fluidized bed furnaces, it is known to use a so-called fluidized siphon. This consists of a downpipe and a container with an overflow. The hot heat transfer medium (e.g. ash) is collected in the downpipe, forms a moving bed there and slips into the container. Air flows through the container through a nozzle base located on the container base, so that fluidization of the heat transfer medium sliding out of the downpipe is achieved and the heat transfer medium can be removed from the overflow of the container. The desired sealing function is achieved by the pressure loss of the fixed bed in the downpipe. The fluidization of the siphon achieves the delivery of the hot medium to a subsequent reactor. Since there are oxidizing operating conditions in fluidized bed furnaces, in which air is added anyway, the air components of the fluidizing agent "air" do not interfere with the process.

When using the method described in the German patent application 100 33 453.9, the use of air as a fluidizing agent for the transport of the heat transfer medium or the ash in the cracking reactor or in the pyrolysis reactor is disadvantageous because in this case oxygen on the one hand and air nitrogen on the other hand in the process would be smuggled in. This is in contrast to the purpose of the method described in German patent application 100 33 453.9 of producing a synthesis gas which is as undiluted as possible and rich in calorific value. The use of air and / or inert gases as a fluidizing agent is not useful under these circumstances. The object of the invention is to propose an improved process for the pyrolysis and gasification of mixtures of substances which contain organic constituents, in particular an improved process according to German patent application 100 33 454.9, and an improved device for carrying out a process for the pyrolysis and gasification of mixtures of substances, which contain organic components, to propose, in particular, an improved device according to German patent application 100 33453.9.

In a method for pyrolysis and gasification of mixtures of substances containing organic constituents, this object is achieved by the features of claim 1. A device according to the invention is the subject of claim 18. Advantageous developments of the method according to the invention and the device according to the invention are described in the subclaims, furthermore in the German patent application 100 33 453.9, which is referred to in full terms and has full priority.

According to the invention, the heat transfer medium is conveyed by means of superheated steam as a fluidizing agent. This can be done in particular by a fluidized siphon. The heat transfer medium or the ashes are transported from the combustion reactor (fluidized bed reactor, fluidized bed furnace) to the pyrolysis reactor (shaft reactor) by or at least with the participation of superheated steam as a fluidizing agent.

Advantageous further developments are described in the subclaims.

The water vapor is preferably heated with energy from the combustion of the pyrolysis coke. Instead or in addition, the water vapor can be heated with energy from the raw gas (pyrolysis gas). This energy can be taken from the hot raw gas, which cools the raw gas. Instead, or in addition, it can be generated by underfiring with raw gas. Another or further possibility is to turn the water vapor off with energy to heat the flue gases. Accordingly, the energy for the fluidizing agent can be provided in-process in various ways.

It is advantageous if the water vapor is used for the fluidization in the cracking reactor. It is therefore possible to use the superheated steam first as a fluidizing agent and then to use the same steam in the cracking reactor / pyrolysis reactor for the cracking reactions.

The heat transfer medium is preferably formed by the ash from the combustion reactor. However, it is also possible to use another heat transfer material or fluidized bed material. The heat transfer medium or the fluidized bed material can contain ash from the combustion reactor or consist exclusively or practically exclusively of this ash.

The ash from the combustion reactor, in particular the ash from the fluidized bed, and / or the pyrolysis coke from the pyrolysis reactor is preferably used as a catalyst for the raw gas. As a result, the catalytic effect of the ash or the pyrolysis coke is used. As a catalyst for the raw gas, the ash and / or the pyrolysis coke can be used alone or with one or more other catalysts.

A further advantageous development is characterized in that a fine fraction is separated from the organic substances before pyrolysis, in particular is sieved off. The fine fraction can also be separated in another way. The screened or otherwise separated fine fraction is preferably fed to the combustion reactor. The screening or other separation and / or the feeding of the fine fraction to the combustion reactor are particularly advantageous when processing Dry ^{Stabilate ®} . Since the fine fraction of the dry stabilate ^{® contains} an increased proportion of inert substances (ash) and pollutants, this is preferably sieved off or otherwise separated off. It is also preferably fed directly to the fluidized bed reactor for further treatment. The advantage can thus be achieved that the pollutant load of the input material (Dry ^{Stabilat ®} ) is led directly to the flue gas cleaning via the fluidized bed reactor - that is, without going through the shaft reactor and the cracking reactor. The flue gas cleaning is carried out according to the valid environmental protection regulations, in Germany currently according to the 17th Federal Immission Control Ordinance (BlmSchV). It prevents pollutant loads from getting into the environment. Another advantage is that the calorific value of the coarse fraction increases compared to the original material, since the fine fraction of the dry stabilate ^{® contains} an increased proportion of inert substances (ash).

A synthesis gas (“fuel gas”) can be generated by the purification or catalytic purification of the raw gas. The synthesis gas is preferably used for energy in a gas turbine or in another heat engine. It is advantageous if the exhaust gas from the energy recovery or the gas turbine The combustion reactor or fluidized bed reactor can also be supplied with air in addition to this exhaust gas. However, it is also possible for the combustion reactor or fluidized bed reactor not to be supplied with air, but exclusively with the exhaust gas from the gas turbine This is possible because the exhaust gas from the gas turbine or other heat engine still has a sufficient oxygen content, which can be around 17%. This enables particularly good energy recovery.

According to a further advantageous development, the synthesis gas is first cooled and / or cleaned before it is used for the combustion chamber of the gas turbine or other heat engine. The cooling and / or cleaning is preferably carried out in a quench. The waste water from the cooling and / or cleaning is preferably evaporated, preferably in a dryer. The remainder from the evaporation (the "thickened" remainder) is preferably fed to the combustion reactor. A further advantageous development is characterized in that a synthesis gas is generated by the cleaning or catalytic cleaning of the raw gas. Hydrogen is preferably separated off from the synthesis gas. The lean gas remaining in the hydrogen separation is preferably fed to the combustion reactor. It can be used thermally there.

It is advantageous if the combustion reactor or fluidized bed reactor is operated in two stages. This occurs in particular in that less air is added to the lower end of the combustion reactor or fluidized bed reactor than is required for stoichiometric combustion. As a result, the ash that is fed to the pyrolysis reactor or shaft reactor still contains coke, which therefore already has a catalytic effect in the upper part of the pyrolysis reactor (shaft reactor, degasifier). Above the removal of the ash from the combustion reactor or fluidized bed reactor, further air is added in order to achieve complete combustion and to be able to release the exhaust gas - cleaned - into the environment.

Another advantageous further development is characterized in that a zone of the pyrolysis reactor or shaft reactor is used as the cracking reactor. This can be done in such a way that the pyrolysis reactor or shaft reactor and the cracking reactor are designed as one component “pyrolysis-cracking reactor”, so that a zone of the pyrolysis reactor is used as a catalyst (FIG. 6) Happen in such a way that the cracking reactor is above the pyrolysis reactor or shaft reactor or that the cracking reactor is in the upper region of the pyrolysis reactor or shaft reactor (FIG. 10).

A further advantageous development is characterized in that the raw gas cleaned in the cracking reactor is further cleaned in a further reactor with a catalyst bed (FIG. 7) or in that the cracking reactor is designed as a reactor with a catalyst bed. The catalyst bed in the further reactor can consist of one or more metal compounds (permanent catalyst). After the gas has left the cracking reactor, it becomes - lo ¬

the other reactor supplied. In this case, the cracking reactor acts as a pre-catalyst. However, the crack reactor is then not absolutely necessary. It is also possible to dispense with the cracking reactor, so that in this case the further reactor with the catalyst bed can act as the actual cracking reactor for the catalytic cleaning of the raw gas generated by the pyrolysis.

It is particularly advantageous if the crude gas cleaned in the cracking reactor is further purified in a further reactor with a catalyst bed, that is to say if a second further catalyst with a catalyst bed is present in addition to the first further reactor with a catalyst bed. It is particularly advantageous here if the first and the second further reactor are activated alternately. The first and the second further reactor are thus operated in such a way that they are alternately active. This enables a further advantageous development, which consists in the fact that the first and the second further reactor can be regenerated alternately, namely in each case when the other further reactor is activated. The regeneration is preferably carried out by hot exhaust gas from the combustion reactor or fluidized bed reactor. The cracking reactor can also be dispensed with when using a first further reactor and a second further reactor. The first and second further reactors then serve as actual cracking reactors for the catalytic purification of the raw gas generated by the pyrolysis.

A further advantageous development is characterized in that the catalyst is added together with the heat transfer medium or that the catalyst takes effect together with the heat transfer medium. As already described, the pyrolysis coke from the pyrolysis reactor can be used as a catalyst for the raw gas. As a result, the catalytic effect of the pyrolysis coke produced in the pyrolysis reactor or shaft reactor is used. To achieve this, the cracking reactor is integrated into the solid stream from the pyrolysis reactor or shaft reactor into the combustion reactor or fluidized bed reactor. Taking into account the temperature level, however, a gas treatment, i.e. a catalytic purification of the raw gas, would be in that area of the pyroly- Sereaktors or shaft reactor desirable, in which the ash from the combustion reactor or fluidized bed reactor is fed, since there the ash (heat transfer medium, fluidized bed material) has the highest temperature level.

To achieve this, the process is preferably carried out in such a way that the catalyst is added together with the heat transfer medium (ash) or that the catalyst takes effect together with the heat transfer medium (ash). For example, the catalyst can be added in the upper region of the pyrolysis reactor or shaft reactor. This can be done together with the ashes. However, the catalyst can also be added in another way. The catalyst can also be present in a cracking reactor to which the ash is fed.

It is possible to use a permanent catalyst, for example metal oxide. When using a permanent catalyst, a cycle results through the combustion reactor or fluidized bed reactor, the thermal cleaning of the catalyst taking place in the furnace. However, a lost catalyst, for example coke or coal, can also be used.

The device according to the invention for the pyrolysis and gasification of mixtures of substances which contain organic constituents, which is particularly suitable for carrying out the process according to the invention, comprises a pyrolysis reactor, preferably a shaft reactor, to which the organic substances or the substance mixture which contains organic constituents, preferably dry ^{stabilizer ®} and a heat transfer medium can be supplied, a combustion reactor, preferably a fluidized bed reactor, for burning the pyrolysis coke from the pyrolysis reactor or shaft reactor and for producing the heat transfer medium, the ash from the combustion reactor preferably being used as the heat transfer medium, and a cracking reactor for cleaning or cracking the raw gas generated by the pyrolysis or its condensable components, in which a catalyst is preferably provided. According to the invention, a fluidized siphon is provided, to which superheated steam can be supplied as a fluidizing agent. The fluidized siphon can consist of a downpipe and a container with an overflow. In this case, the heat transfer medium or the hot ash is collected in the downpipe. There it forms a moving bed and slips into the container. The container can be overflowed with superheated steam through a nozzle base located on the container bottom, so that the ash slipping out of the downpipe is fluidized and the ash can be drawn off from the overflow of the container. The pressure loss of the moving bed in the downpipe achieves the desired sealing function, i.e. the sealing against gases (pyrolysis gases from the pyrolysis reactor (s) that must not get into the fluidized bed furnace and flue gases from the fluidized bed furnace that must not get into the pyrolysis reactor). By fluidizing the siphon, the hot medium (heat transfer medium, hot ash) is conveyed into a downstream reactor (pyrolysis reactor / cracking reactor). A small part of the water vapor can penetrate into the combustion reactor or fluidized bed furnace through the moving bed and thus act as sealing gas.

Advantageous further developments are described in the further subclaims.

The fluidized siphon preferably comprises a downpipe.

A moving bed can be provided in the downpipe. The downpipe is preferably designed such that a moving bed can be formed therein. Design parameters and / or operating parameters are preferably influenced in such a way that a moving bed is formed in the downpipe.

A further advantageous development is characterized in that water can flow through the downpipe or the moving bed. The water vapor can act as a sealing gas. The design parameters and / or operating parameters are preferably influenced in such a way that water vapor as a sealing gas flows through the downpipe or the moving bed. The invention provides a method and a device by means of which a clean gas can be generated from a fuel with a certain ash content and high volatile content, which is suitable for use in gas turbine processes and internal combustion engines as well as for material recycling, that is to say of very high quality is. The objective is achieved that no technical oxygen has to be used and that the pyrolysis gas does not come into contact with inert gases. The invention is particularly suitable for processing Dry ^{Stabilat ®} . It can be assumed that the fine fraction of Dry Stabilate ^{® contains} on the one hand an above-average number of pollutants and on the other hand a high inert fraction (approx. 50% by weight), so the contribution of the fine fraction to a high-quality gas is low and the negative effects on the effort of the Pyrolysis gas purification are relatively high. The heat transfer medium is generated from the pyrolysis coke by combustion. The entire feed material (organic substances, in particular Dry ^{Stabilate ®} ) with the fine fraction goes through pyrolysis and pollutes gas cleaning. The fine fraction is preferably fed directly to the combustion; In the combustion reactor, the heat transfer medium is generated from this fine fraction and the pyrolysis coke. The volatile pollutants of the fine fraction can be discharged in the combustion and separated in the flue gas cleaning. This prevents contaminants from the fine fraction from entering the pyrolysis gas and making gas cleaning unnecessarily complex and expensive.

The pyrolysis gas or synthesis gas produced in the implementation of the invention can be used for material and energetic use, in particular for generating electricity, for generating heat, for producing methanol or for producing hydrogen. It is possible to generate a hydrogen-rich gas. The invention can be used to generate electricity, particularly in a gas turbine. The gas turbine exhaust gas can be used as combustion and fluidizing air in the fluidized bed of the fluidized bed reactor. However, the system must then be operated under pressure or a combustion to provide gas compressors. The furnace in the combustion reactor or fluidized bed reactor provides heat for the pyrolysis reactor. The heat transfer medium, namely ash, is also generated in the process by the fluidized bed. If coke or pyrolysis coke is used as the catalyst material, this can also be generated internally in the process by staged air supply in the fluidized bed. A procedure with substoichiometric combustion is possible. It is also possible to carry out the aftertreatment of the pyrolysis gases directly in the degasser (pyrolysis reactor); degassing and cracking can thus be carried out in one reactor.

Embodiments of the invention are explained below with reference to the accompanying drawings. In the drawing shows

1 shows a device for carrying out a method for pyrolysis and gasification of substance mixtures which contain organic constituents, in a schematic representation,

2 shows the device according to FIG. 1, the shaft reactor and the cracking reactor being designed as one component “pyrolysis-cracking reactor”,

Fig. 3 shows another embodiment in which the catalyst is added together with the heat transfer medium or is effective and

Fig. 4 shows a fluidized siphon, to which superheated steam can be supplied as a fluidizing agent, in a schematic representation.

The basic configuration shown in FIG. 1 for carrying out the basic process consists of a shaft reactor 1, a fluidized bed reactor 2 and a cracking reactor 3. The shaft reactor 1 is made up of the organic substances, preferably Dry ^{Stabilate ®} 4, and the heat transfer medium, preferably ash 5 fed to the fluidized bed reactor 2. The dry stabilizer 4 introduced into the shaft reactor 1 is mixed there with the hot ash 5 from the fluidized bed reactor 2. The dry stabilizer heats up and degasses (pyrolyzes). A gas is produced, namely the raw gas 6, and a solid 7, namely pyrolysis coke and ash. The raw gas 6 leaves the shaft reactor 1 at the upper end, the solid 7 leaves the shaft reactor 1 at the lower end. Raw gas 6 and solid 7 are fed to the cracking reactor 3. Since the solid 7, namely the pyrolysis coke contained therein, acts as a catalyst for gas cleaning, the raw gas 6 is passed through the hot solid in the cracking reactor 3. Water vapor 8 is also added here. As a result, a catalytically cleaned gas 9 (synthesis gas, fuel gas) is obtained. The solid 10 from the cracking reactor 3 (pyrolysis coke and ash) is introduced into the fluidized bed reactor 2 and burned there with air 11. The exhaust gas 12 from the fluidized bed of the fluidized bed reactor 2 is cleaned. Ash 13 which is not yet required can also be drawn off from the fluidized bed reactor 2.

In the embodiment shown in FIG. 2, the shaft reactor and the crack reactor are designed as one component, namely as a pyrolysis-crack reactor 30. One zone, namely the lower zone, of the pyrolysis reactor 1 is used as a catalyst.

In the embodiments shown in FIGS. 1 and 2, the catalytic effect of the pyrolysis coke produced in the shaft reactor 1 is used. In these embodiments, the cracking reactor 3 is integrated in the solid stream from the shaft reactor 1 into the fluidized bed reactor 2. If the temperature level is taken into account, however, gas treatment would be desirable in the area of the shaft reactor 1 in which the ash 5 is fed from the fluidized bed reactor 2, since there the solid matter (the ash) has the highest temperature level.

In order to achieve this, the process control according to FIG. 3 can be provided. Here, a catalyst 40 is added in the upper region of the shaft reactor 1. The shaft reactor and the crack reactor are also designed here as one component, namely as a pyrolysis-crack reactor 30 '. However, the addition of the catalyst 40 in the upper region of the shaft reactor 1 does not necessarily have to take place with the ash 5 from the fluidized bed reactor 2. The catalyst can also be added in other ways. Furthermore, the catalyst can be present in the upper region of the shaft reactor 1, that is to say in the region of the pyrolysis-cracking reactor 30 ′ which is designated by 41. In the embodiment of Fig. 10, a permanent catalyst such as metal oxide can be used. However, a lost catalyst such as coke or coal can also be used. When using a permanent catalyst, a cycle results through the fluidized bed reactor 2, the thermal cleaning of the catalyst taking place in the furnace of the fluidized bed reactor 2. The cracking reactor is automatically integrated into the shaft reactor 1 so that it becomes the pyrolysis-cracking reactor 30 '.

FIG. 4 shows a plant part that can be used in the embodiments according to FIGS. 1 to 3, through which hot ash or another fluidized bed material from the fluidized bed reactor or fluidized bed furnace 2 to the pyrolysis reactor or shaft reactor 1 or to the pyrolysis-crack reactor 30 or 30 ' can be promoted. In the fluidized bed furnace 2 there is a fluidized bed 41 ', which consists of fluidized bed material, namely hot ash. The bottom of the fluidized bed furnace 2 is designed as a nozzle base 42 through which fluidizing air 43 is fed to the fluidized bed furnace 2.

The hot ash from the fluidized bed 41 'is fed to a cracking reactor / pyrolysis reactor / shaft reactor / pyrolysis / cracking reactor 1, 3, 30, 31, 30', 41 ', which are not shown in FIG. 4 and which are shown in FIG The material flow direction is behind arrow 44.

The fluidized siphon 45 shown in FIG. 4 comprises a down pipe 46, which can also be designed as a down shaft, and a container 47 with an overflow. The hot ash from the fluidized bed 41 ′ passes through the in the fluidized bed furnace 2 trained ash overflow 48 into the downpipe 46, where it is collected. This hot ash forms a moving bed in the downpipe 46 and slips into the container 47. The bottom of the container 47 is designed as a nozzle base 49, through which superheated steam 50 is fed to the container 47.

With the help of the superheated steam 50, the container 47 is flowed through the nozzle bottom 49 located on the container bottom, so that fluidization of the ash slipping out of the downpipe 46 is achieved and the ash can be drawn off from the overflow of the container 47 into the further downpipe 51. It is led from the further downpipe 51 in the direction of arrow 44 to the shaft reactor 1 / pyrolysis-crack reactor 30 / pyrolysis-crack reactor 30 '.

The desired sealing function is achieved by the pressure loss of the fixed bed in the downpipe 46. The fluidized siphon according to FIG. 4 fulfills the functions of conveying a solid and sealing against gases. The fluidization of the siphon achieves the delivery of the hot medium into a subsequent reactor 1, 30, 30 '.

The downpipe 46 in conjunction with the fluidized siphon 45 enables a separation of the oxidizing atmosphere in the combustion reactor or fluidized bed furnace and the reducing atmosphere in the cracking reactor and in the pyrolysis reactor. A defined, very small steam flow penetrates through the moving bed in the downpipe 46 into the combustion reactor or fluidized bed furnace and thus acts as a sealing gas. This sealing steam flow can be set in a targeted manner by permanently setting a pressure drop across the moving bed in the downpipe 46. This drop in pressure can be influenced by the height of the moving bed (design parameters) and by the vapor admission pressure and the negative pressure in the combustion reactor or fluidized bed furnace (operating parameters). An influencing by other and / or further design parameters and / or operating parameters is possible. The main stream of water vapor either enters the cracking reactor together with the ash or additionally via a bypass and thus blocks the siphon against raw gas from the cracking reactor. In the process according to German patent application 100 33 453.9, superheated steam with an initial pressure of 1.0 to 1.5 bar and around 800 ° C. to 850 ° C. can be used in the pyrolysis reactor to carry out the desired cracking reactions. It is thus possible to first use the superheated steam 50 as a fluidizing agent and then to use the same steam in the cracking reactor / pyrolysis reactor 1, 3, 30, 31, 30 ', 41 for the cracking reactions. The amount of superheated steam from the fluidization of the siphon, at around 0.07 to 0.12 kg of steam per kg of Dry ^{Stabilat ®, is} significantly less than the total amount of steam required of around 0.3 kg of steam per kg of Dry ^{Stabilat ®,} and therefore in no way harmful to the process but even beneficial.

The energy for providing the steam at 1.5 bar and 800 to 850 ° C. can be obtained from the cooling of the flue gases from the combustion of the pyrolysis coke. The energy for the provision of the fluidization means can thus be generated or used in-process.

Surprisingly, it has been shown that the superheated steam mixed as a fluidizing agent does not lead to a reduction in the calorific value of the synthesis gas mixed therewith in the further course of the process. This particular advantage can be achieved in connection with the process according to German patent application 100 33 453.9, because the supply of superheated steam cracks longer-chain hydrocarbons in the pyrolysis gas and thus increases the calorific value of the synthesis gas. The desired cracking reactions are therefore a special feature which makes it particularly useful to use superheated steam as a fluidizing agent without the synthesis gas deteriorating and without the water vapor being produced as additional condensate when the synthesis gas is cooled.

Claims

claims

1. Process for the pyrolysis and gasification of mixtures of substances which contain organic constituents,

in which the organic substances (4) or the substance mixture containing organic constituents are brought into contact with a heat transfer medium in a pyrolysis reactor (1) and pyrolysed,

in which the pyrolysis coke (7) formed by the pyrolysis is burned in a combustion reactor (2) with air supply (11),

and in which the condensable constituents of the raw gas (6) generated by the pyrolysis are cracked in a cracking reactor (3),

characterized,

that the heat transfer medium is conveyed by means of superheated steam (50) as a fluidizing agent.

2. The method according to claim 1, characterized in that the water vapor (50) is heated with energy from the combustion of the pyrolysis coke and / or with energy from the raw gas (6).

3. The method according to claim 1 or 2, characterized in that the water vapor (50) is heated with energy from the flue gases.

4. The method according to any one of the preceding claims, characterized in that the water vapor (50) for the fluidization in the cracking reactor (1, 3, 30, 31, 30 ', 41) is used.

5. The method according to any one of the preceding claims, characterized in that the heat transfer medium consists of the ashes (5) of the combustion reactor (2).

6. The method according to any one of the preceding claims, characterized in that a catalyst is provided in the cracking reactor (3).

7. The method according to any one of the preceding claims, characterized in that the cracking is carried out with the addition of water vapor (8).

8. The method according to any one of the preceding claims, characterized in that the pyrolysis coke (7) from the pyrolysis reactor (1) and / or the ash from the combustion reactor (2) is used as a catalyst for the raw gas (6).

9. The method according to any one of the preceding claims, characterized in that a fine fraction is separated from the organic substances (4) before pyrolysis.

10. The method according to any one of the preceding claims, characterized in that a synthesis gas is generated by the purification of the raw gas.

11. The method according to claim 10, characterized in that hydrogen is separated from the synthesis gas.

12. The method according to any one of the preceding claims, characterized in that a zone of the pyrolysis reactor (1) is used as a cracking reactor (Fig. 2; Fig. 3).

13. The method according to any one of the preceding claims, characterized in that the catalyst is added together with the heat transfer medium or is effective (Fig. 3).

14. The method according to claim 13, characterized in that the catalyst (40) is added to the heat transfer medium (5).

15. The method according to claim 13 or 14, characterized in that a permanent catalyst is used.

16. The method according to any one of claims 13 to 15, characterized in that a lost catalyst is used.

17. Device for the pyrolysis and gasification of mixtures of substances which contain organic constituents, in particular for carrying out the process according to one of claims 1 to 16

with a pyrolysis reactor (1), preferably a shaft reactor, to which the organic substances (4) or the mixture of substances containing organic components and a heat transfer medium (5) can be fed,

a combustion reactor (2), preferably a fluidized bed reactor, for burning the pyrolysis coke (7) from the pyrolysis reactor (1) and for generating the heat transfer medium (5) for the pyrolysis reactor (1)

and a cracking reactor (3) for cracking the condensable components of the raw gas (6) generated by the pyrolysis, marked by

a fluidized siphon (45) to which superheated steam (50) can be supplied as a fluidizing agent.

18. The apparatus according to claim 17, characterized in that the fluidized siphon (45) comprises a down pipe (46).

19. The apparatus according to claim 18, characterized in that a moving bed is provided or can be formed in the down pipe (46).

20. The apparatus of claim 18 or 19, characterized in that the downpipe (46) or the moving bed of water vapor can be flowed through.

21. Device according to one of claims 17 to 20, characterized in that a catalyst is provided in the cracking reactor (3).

22. The device according to one of claims 17 to 21, characterized by a quench for cooling and / or cleaning the synthesis gas (9).

23. The device according to claim 22, characterized by a dryer for cooling and / or purifying the waste water from the quench.

24. Device according to one of claims 17 to 23, characterized by a hydrogen separation for separating hydrogen from the synthesis gas from the cracking reactor (3).

25. Device according to one of claims 17 to 24, characterized in that the pyrolysis reactor (1) or shaft reactor and the cracking reactor (3) are designed as one component, preferably as a pyrolysis-cracking reactor (30, 30 ').

26. Device according to one of claims 17 to 25, characterized by a further reactor with a catalyst bed.

27. The apparatus according to claim 26, characterized by a second further reactor with a catalyst bed.