EP2281864B1 - Method and apparatus for gasifying solid fuels - Google Patents

Description

The present invention relates to a device according to the preamble of claim 1 and a method according to the preamble of claim 8.

The invention thus relates to a method and to the devices of a working in vacuum autothermal DC fixed-bed gasifier with internal circulation to produce a nearly tar-free wood gas from wood chips or woody biomass for motor use, which produces mainly by optimizing the thermochemical process of gas reduction becomes. The goal is to increase the continuous production of wood gas with high quality and quantity by the gas reduction, which can be finally used with little effort of a dry gas treatment (dedusting and cooling) in internal combustion engines to generate electricity and heat. An alternative is also the utilization of the wood gas for biodiesel production, e.g. according to Fischer Tropsch method. Constructive devices for reducing gas to prevent the problematic tar formations in order to avoid a complex pyrolysis gas wash. With the known technique of hot gas filtration (dry gas cleaning), the wood gas to be cleaned without much effort in high temperature resistant ceramic filter cartridges of coal dust and then cooled in the engine to be burned.

With the method and the constructive devices economic competitive advantages are achieved, avoided in the high investment and operating costs of complex processes or for a Pyrolysisgaswäsche to remove the tars and their disposal of pyrolysis residues and the energy loss of the calorific value of deposited hydrocarbons in the wood gas and to overcome pressure losses in the system can be. With this wood gas reduction process, a higher efficiency is achievable compared to other methods.

To achieve maximum gas from the carburetor fuel fresh gas-rich dried wood chips from biomass with a mean piece size of about 30 mm to 70 mm and a maximum water content of 20% is used.

From the DE 102 58 640 A a method of the type described above is known in which a gasification agent is injected into the middle region of a fixed bed reactor and is divided into a first and a second partial flow. The first partial stream withdrawn above is postoxidized in an oxidation chamber and subsequently added to the second partial stream. The resulting gas mixture is aftertreated in a fluidized bed reactor. The method described in this document is complex in terms of apparatus and requires in addition to the fixed bed reactor, a separate oxidation chamber and a fluidized bed reactor. It is an object of the invention to provide a process for the gasification of solid fuels, which has a high efficiency and results in a high quality end product.

From the WO 2008/107727 A is a three-stage pyrolysis reactor is known in which pyrolysis gas is sucked up, in the upper third air is blown, in the lower third air is blown with the externally guided down pyrolysis and down clean gas is withdrawn. The construction of this device is relatively complex, since several blowers are provided to move the individual gas streams. In addition, a complex temperature management is required by the outward gas streams. Due to the three-stage nature of the process, the reactor as a whole builds relatively high.

Similar disadvantages arise in the solution, as in the US 4,306,506 A is described. Again, the pyrolysis gases are first led to the outside, to be subsequently introduced into the reactor again. This object is achieved by a method according to the features of claim 8. In particular, such a method is characterized in that via the device internal vertical side channels in the fixed bed reactor by the suction of the formed during the gasification ascending Schwel- and pyrolysis gases through the diffuser Injektoreinblasdüsen (injector) an internal circulation of the gases is effected and these mixed with the gasification agent are blown over the 8-jet nozzle ring in the oxidation zone.

Due to the intensive turbulence of the gas mixture - similar to an oil burner - the complete combustion of the tar-containing raw gases or the cracking of the long-chain hydrocarbon chains occurs in the oxidation zone.

Below the nozzle plane at the end of the bottleneck constriction, the device of a spacious pan grate allows sufficient formation of a continuous charcoal emberstock as a reduction zone to produce a nearly tar-free wood gas by a full gas reduction requiring only a dry gas treatment.

This method with the internal gas circulation constructive devices and the intensive diffuser injector injection of the raw gases into the oxidation zone utilizing the injector flow energy for conveying, mixing and blowing as well as the continuous charcoal stock formation in the large scale Sink grate as a reduction zone largely meets the requirements of ideal conditions of the catalytic and thermal gas formation processes to produce a nearly tar-free product gas.

• der gleichmäßige, vollständige Ablauf der Reaktionen;
• die ausreichende Verweildauer der Gase in den Reaktionszonen;
• die optimale Temperaturverteilung im Reaktor nach den Betriebsbedingungen

In this DC gasifier with internal circulation of the pyrolysis smolder gases, the required parameters and parameters of physical and chemical processes according to the Boudouard equilibrium, the hydrogen equilibrium and the methane balance for a good gas quality and quantity are implemented. These are

• the uniform, complete course of the reactions;
• the sufficient residence time of the gases in the reaction zones;
• the optimal temperature distribution in the reactor according to the operating conditions

The method for producing wood gas by gasification of biomass from wood is state of the art, but the production of a virtually tar-free wood gas has so far been possible only with considerable expenditure.

The basis of all carburetors according to the principle of descending direct current served the wood gasifier to Imbert as a fixed bed reactor, this dried lumpy wood and the gasification agent air-oxygen is supplied via air nozzles substoichiometric to the combustion or oxidation. In this case, the wood is generally thermally decomposed into different components.

In the decomposition of the wood in the gasification process arise in a fixed bed different temperature zones, which are not separated, but between which a smooth transition takes place.

These temperature zones, which are passed through the carburettor fuel wood chips are generally the drying zone at temperatures up to 200 ° C, the pyrolysis (decomposition, degassing) at temperatures between 200 ° C - 700 ° C, the oxidation zone or combustion zone at temperatures up to 1300 ° C. and the reduction zone at temperatures between 500 ° C - 600 ° C.

In order to keep the energy-consuming zones of drying, pyrolysis and reduction in progress (endothermic processes), in the field of combustion (oxidation) for thermal energy production of a suitable carburetor fuel from wood chips (bulk, calorific value) and a sophisticated device for the production of combustible gas components (CO, H ₂ ) as well as non-combustible gaseous intermediates (CO ₂ , H ₂ O) (exothermic process).

In the course of combustion or oxidation, energy is released by heat, which decomposes and degasses the overlying wood chips and further pre-dries in the upper area. In the oxidation zone, charred wood or charcoal forms, which forms the reduction zone, where part of the combustion products (CO ₂ , H ₂ O) is reduced to further combustible gas components (CO, H ₂ , CH ₄ ) as a gas mixture.

In the production of charcoal, the volume of wood chippings decreases, so that a constriction of the reactor in the transition region from the oxidation zone to the reduction zone is provided to form a compact reduction zone in the carburetors.

The combustible gas mixture produced from the reduction zone is discharged or sucked off substantially vertically in direct current through the grate or its slots for gas treatment. Here, the coal dust with the resulting wood ash is separated from the gas mixture.

The general problem of DC fixed bed gasification plants known methods is still the mastery of the individual complex process steps to avoid the production of tars or hydrocarbons in the gas mixture due to insufficient gasification. Here are the problems of accumulation of rising tar-containing sulfur and pyrolysis gases in the upper carburetor and the dissatisfied solution of a gas treatment are known.

Another reason for the high proportion of pyrolysis gases unburned hydrocarbon chains is the operation of large-volume gas reactors with carburetor fuels of different piece size and humidity. In these reactors, the reduction zone is designed undersized in relation to the oxidation and pyrolysis, whereby no sufficient gas reduction can take place and thus a complex gas treatment is required.

Therefore, complex multi-stage gasification concepts have recently been developed to prevent the well-known tar load in the product gas. Here, the goal is pursued to split the complex gas streams and bring them to produce a pure product gas in suitable controllable reaction states. This requires a corresponding technical effort for the control of the gas flows and an additional energy input for gas treatment at the required high temperature conditions of 1300 ° C for thermal cleavage of tar components.

So are the multi-stage gasification plant DE 102 58 640 A1 the split into two partial gas streams in a countercurrent process and down from the fixed bed in a DC process. For controlling The volume ratios are used throttle bodies. The upwardly led partial gas stream is fed via the fuel bed for separate oxidation in an oxidation chamber and substoichiometrically oxidized by addition of combustion air at 1100 ° C - 1,300 ° C, so as to crack or oxidize the unwanted, long-chain hydrocarbon compounds can. A second untreated partial gas stream is converged downwardly from the fixed bed gasifier in direct co-current with the first hot exhaust gas from the oxidation chamber and mixed. The downwardly diverted partial gas stream also serves as a transport medium for the required Reduktionskoks in the reduction chamber, which is mixed with the first treated water vapor-rich gas stream is introduced for common gas reduction in the downstream reduction chamber. The pneumatic transport of the coke is supported by the supply of the exhaust gas from the oxidation chamber, wherein the formed as a fluidized bed reduction reactor with the incoming and koksführenden gas forms the combustible gas components H2 and CO.

This multi-stage gasification process by separation of the gas streams into individual reaction chambers by means of the control by throttle bodies is very expensive for the cracking or oxidation of undesirable long-chain hydrocarbon compounds with subsequent gas reduction and is known to be applied to fluidized bed gasifiers.

Another method for reducing the tar content in the product gas is in EP 0 693 545 A1 described, where in the region of the constriction in the gasifier chamber, a gas ring channel is provided, in which the recovered gas is subjected to a second combustion in the annular channel. Instead of taking the gas out of the annulus, this is to flow through the nozzle ring in the hottest zone at about 1,000 ° C in order to burn tar. By switching means, the gas can be removed directly from the gasification zone or by mixing the two gas streams from the gasifier.

These developments show various solutions for the possible reduction of the tar content in the product gas, which however are not comparable with the present invention of the fixed bed direct current gasifier with internal circulation of the raw gases. The technical solution to the known problems of gasification is achieved with the invention of Gleichstromvergasers with internal circulation, characterized in that the rising tar rich Schwel- and pyrolysis gases, which arise during the decomposition and degassing by the combustion (oxidation) of the carburetor, via the inner vertical side channels be sucked in the reactor with the help of the diffuser injector nozzle effect (injector conveyor technology) in the upper carburetor space.

In this case, the tarry-rich carbonization and pyrolysis gases (conveying medium) are mixed with the gasification medium (blowing medium) by suction through the eight arranged diffuser nozzles and blown the carburetor in the oxidation zone for combustion or energy production with pressure energy. Due to the intensive turbulence of the gas mixture, as in the case of an oil burner, complete combustion of the tar-containing raw gases or cracking of the long-chain hydrocarbon chains occurs in the oxidation zone.

The diffuser injection nozzles simultaneously effect by suction, mixing and blowing of the media a constant internal circulation of the gas streams in the reactor and thus a uniform temperature distribution, a complete flow of the thermochemical reactions with a sufficient Verändauer to reduce gas.

These reaction and flow processes of the gases above the nozzle level occur in countercurrent to the course of the fuel guide in the gasifier (area A) and arise from the release of heat energy in the supply of the air-oxygen gas mixture (stoichiometric combustion) in the zones of partial oxidation, Pyrolysis and drying.

The advantages of this method and the device for extracting the tar-containing carbonization and pyrolysis gases in the upper carburetor space via the injector conveyor of the diffuser Injektoreinblasdüsen are especially the energy gain from the complete combustion of the tar-containing gases for further gas reduction, the prevention of non-hazardous gas leakage via the fuel supply Opening and avoiding additional expenses for removal and further gas treatment of the carbonization and pyrolysis gases.

Below the nozzle level (area B) is at the end of the bottleneck-shaped constriction, the device of a spacious 8eckigen tub grid for receiving a sufficient charcoal embers stock as a reduction zone for gas production.

In the decomposition, degassing and oxidation (combustion) of the carburetor fuel is continuously formed a charcoal liqueur, which renewed in the gas reduction.

In the printing operation and in the direct current, the oxidation products produced during the combustion (CO2, H2O) this glowing charcoal are drawn in the trough grate with the suction force of the gas engine and thereby to burning gases (CO, H _2, CH ₄₎ is reduced.

Due to the proportional oversize compared to the size of the oxidation and pyrolysis zone, this device of a spacious 8-sided bath grid provides the prerequisite for complete gas reduction and thus the production of a virtually tarry product gas.

The transition from the oxidation zone into the reduction zone in the area of the bottle-neck constriction with the conclusion of the oblique trapezoidal 8eckigen grid grid also allows a homogeneous temperature distribution and intensive flow of gases, whereby the interactions of the reactions between oxidation and reduction are optimized for gas reduction.

Compared to the multi-stage gasification plant DE 102 58 640 A1 differs the DC fixed-bed gasifier with internal circulation of the swelling and pyrolysis gas to the effect that no external separation of the gas streams for a separate gas treatment (oxidation-reduction chamber) is present, no throttle bodies and no pneumatic transport of coke for a formed as a fluidized bed reduction reactor, but the Optimization of all interactions between oxidation and reduction or the complex gas formation processes to obtain a nearly tar-free wood gas take place in a gasification reactor.

Likewise the wood gas producer corresponds EP 0 693 545 A1 in which, in the area of the constriction in the gasifier chamber, a gas ring channel is provided for combustion of tar constituents, not the present invention, when a gas mixture is blown into the oxidation zone for complete combustion by means of an 8-jet nozzle ring with diffuser injection nozzles.

• durch das Absaugen und Vermischen der zirkulierenden Schwell- und Pyrolysegase mit dem Vergasungsmittel über den Injektorförderer der Diffusor-Injektordüsen (Fig. 3) und durch das Einblasen dieses Gasgemisches in die Oxidationszone wird eine intensive Verbrennung bzw. Oxidation mit hohen Temperaturen von etwa 1.300°C erreicht, wobei eine Crackung der Teere bzw. unerwünschter langkettiger Kohlenwasserstoffverbindungen gegeben ist;
• durch die Diffusor-Injektorwirkung wird der Antrieb der Gaszirkulation über den mindestens 8strahligen Düsenkranz in Gang gehalten, wodurch eine gleichmäßige Temperaturverteilung und eine ausreichende Verweildauer der Gase für den vollständigen Ablauf der Gasreduktion erreicht wird;
• mit der Vorrichtung eines proportional übergroßen 8eckigen Wannenrostes ist eine ausreichende Menge glühender Holzkohle als Reduktionszone vorhanden, die eine vollkommene Reduktion der Oxidationsprodukte für die Erzeugung eines nahezu teerfreien Holzgases ermöglicht.

The advantages of this method and the constructive devices of the autothermal-pressure DC fixed bed gasifier with internal circulation are after Fig. 1 . FIG. 2 and FIG. 3 - as follows - given:

• by sucking off and mixing the circulating swelling and pyrolysis gases with the gasification agent via the injector conveyor of the diffuser injector nozzles ( Fig. 3 ) and by injecting this gas mixture into the oxidation zone, an intensive combustion or oxidation with high temperatures of about 1300 ° C is achieved, wherein a cracking of the tars and unwanted long-chain hydrocarbon compounds is given;
• by the diffuser-injector action, the drive of the gas circulation via the at least 8-jet nozzle ring is kept in motion, whereby a uniform temperature distribution and a sufficient residence time of the gases is achieved for the complete course of the gas reduction;
• with the device of a proportionally oversized 8eckigen gridiron a sufficient amount of glowing charcoal is available as a reduction zone, which allows a complete reduction of the oxidation products for the production of a nearly tar-free wood gas.

The process and the technical devices can be used to produce the required operating conditions for the interaction between oxidation and reduction or the catalytic and thermal gasification processes such as the Boudouard equilibrium, the water gas equilibrium and the methane equilibrium under favorable conditions for investment and operation unburned hydrocarbons or tar distillates in the wood gas are given more.

In this way, the complex processes of combustion and gasification can be implemented to produce a product gas of the highest quality and quantity with the aim of minimizing the expense of dry gas treatment (hot gas filtration for dedusting) and cooling of the gas for engine use.

Due to the described process chains, the continuous gasification process of wood biomass requires a large number of plant components and process technologies, all of which must be coordinated in order to avoid malfunctions on the one hand and to achieve maximum efficiencies with the best gas quality and quantity on the other hand.

• Brennstoffaufbereitung (Hacken, Sieben), kontinuierliche Trocknung, Beschickung der Vorratsbehälter und des Vergasers, Nachverbrennung oder Gasfackel, Entstaubung durch Heißgasfiltration, Gaskühlung und die Erzeugung von Strom und Wärme in einem Gasmotor-Heizkraftwerk.

The implementation of the process chains of a holistic gasification system is the product of a wood gas power plant system with the following linked system components:

• Fuel preparation (chopping, screening), continuous drying, charging of the reservoir and the carburetor, afterburning or gas flare, dedusting by hot gas filtration, gas cooling and the generation of electricity and heat in a gas engine power plant.

1. 1. die abnehmbare feuerbeständige gasdichte Abdeckung 24 des Vergasers mit Befestigung 23 und der Beschickungseinrichtung einer Doppelschieberschleuse mit Motorantrieb 10;
2. 2. der Stahlmantel als Zylindergefäß 1 mit der feuerfesten Mauerung 9 und integrierten Belüftungskanälen 6 sowie Anschlüssen von Armaturen 8;
3. 3. der abnehmbare Unterteil des Reaktors 23 mit der außen liegenden Ringrohrleitung 4 und dem Anschluss an die 8strahligen Diffusor-Injektordüsen 5 als Düsenkranz, in dem zur Verbrennung bzw. Vergasung des Brennstoffes das Gasgemisch 22 aus Pyrolysegas 7 mit dem Vergasungsmittel 4 eingeblasen wird und dem 8eckigen schrägförmigen Wannenrost 3 mit einem beweglichen Unterteil des Rost für Hand- oder Motorbetrieb 12, für die Aufnahme des Holzkohlenglutbettes als Reduktionszone sowie den darunter liegenden schräg eingeengten Abgang als Aschenschacht 13 mit motorischer 19 Austragung 18 der Asche in dem gasdichten Aschenbehälter 20, den beweglichen Rost 3 sowie den Gasaustrittstutzen 14,25.

The invention of the DC reduction fixed bed gasification reactor with internal circulation is as follows Fig. 1 , and Fig. 2 under construction for service reasons (Maintenance, repair) of three separate demountable structural parts, which is supported by a 4eckigen steel framework 21 to four suspensions 26.

1. 1. the removable fire-resistant gas-tight cover 24 of the carburetor with attachment 23 and the loading device of a double-slider lock with motor drive 10;
2. 2. the steel shell as a cylinder vessel 1 with the refractory wall 9 and integrated ventilation ducts 6 and fittings of valves 8;
3. 3. the removable lower part of the reactor 23 with the outer ring pipe 4 and the connection to the 8-jet diffuser injector nozzles 5 as nozzle ring in which the gas mixture 22 of pyrolysis gas 7 is blown with the gasification agent 4 for combustion or gasification of the fuel 8eckigen diagonal gridiron 3 with a movable base of the grate for manual or motor operation 12, for receiving the charcoal embers bed as a reduction zone and the underlying obliquely narrowed outlet as ash shaft 13 with motor 19 discharge 18 of the ash in the gas-tight ash container 20, the movable grate 3 and the gas outlet pipe 14,25.

The pressureless-autothermal DC fixed-bed gasifier reactor space 2 has with the refractory lining 9 a bottle neck shape - comparable to the blast furnace. This constriction in the transition zone of the oxidation zone in the reduction zone is an intense mass transfer between the reacting surface of the charcoal stock and the gas components (CO2, H2O) to form the gas reduction (CO, H2, CH4).

To Fig. 1 is fed via a conveyor belt continuously carburetor fuel, consisting of lumpy wood chippings of the largely airtight fire-proof double-slider lock 10, which is introduced after reporting the paddle 8 in the reactor chamber 2.

The gasification material in the reactor chamber 2 passes from top to bottom through the zones of drying, pyrolysis (decomposition, degassing), oxidation and reduction. During the combustion in the oxidation zone, temperatures up to more than 1200 ° C. form on the nozzle level in the ember bed above the sump grate 3, with the energy released keeping the gasification processes of the individual zones going. In this case, the resulting swelling and pyrolysis gases rise countercurrently in the upper gasification chamber 7.

Over at least eight evenly distributed injector nozzles 4, in the form of a diffuser - see Fig. 3 - Which are connected to the outer ring pipe 4 to the gasifier reactor 1, the ascending in the gasification chamber 7 pyrolysis gases are sucked through the vertically integrated in the refractory lining 9 side channels 6 by the injector and mixed with the gasification agent from the tubes 4, 5 as Gas mixture 22 for common combustion with the carburetor fuel 2 is blown into the oxidation zone.

By this suction of the volatile fugitive gases or tar pyrolysis gases 7, which arise in the reactions of drying, decomposition, degassing by the combustion of the carburetor fuels in ascending, an internal circulation of the gas streams through the gasifier chamber is set in motion. The flow through the carburetor fuel or the circulation of the gas streams of unburned hydrocarbons favors a uniform temperature distribution in the gasification reactor and in this way enhances the complete course of the equilibrium reactions.

By sucking the ascending pyrolysis gases in the upper gas chamber 7 via the inner side channels 6, the well-known problem of unwanted gas leakage at the opening for fuel introduction is achieved in the carburetor. The non-hazardous pyrolysis gases rising countercurrently in the upper carburetor space are usually fed to a gas purifier at great expense, depending on the process.

After the intensive mixing process between the pumped medium of the swelling and pyrolysis gas and the propellant of the gasification agent (eg atmospheric oxygen) causes the pressure energy of the diffuser injector nozzles 5 during injection of the gas mixture 22 in the charcoal bed optimum combustion of the gas mixture or cracking of the tar-containing swell and pyrolysis. The substoichiometric addition of combustion air leads to the energy gain to a high temperature rise (exothermic process) to about 1,100 ° C to 1,200 ° C, whereby a substantial cleavage or conversion of the unburned hydrocarbons in the chemical components (CO2, H2O) is achieved.

To increase the efficiency of the gasification agent is preheated over at least eight evenly distributed air nozzles 5 blown into the center of the reactor, which are connected to the outer ring line 4 to the carburetor as a nozzle ring.

Below the injection nozzles in the middle of the reactor vessel, a spacious grid in the form of a 8eckigen tub 3 is placed with oblique side walls in which continuously forms a charcoal stock as a reduction zone or as a catalyst for gas reduction.

Through the slot-shaped fire-resistant openings of the tub grid 3, the product gas formed in the reduction zone (exothermic process) exits downwards in the prevailing negative pressure operation, which is generated by the suction motor or exhaust gas fan.

The product gas leaves the gas outlet via the refractory opening 14, the lateral gas outlet pipe 25 and is supplied to a gas cleaning or cooling before use in the motor thermal power plant.

When the product gas flows through the charcoal, the wood ash produced during combustion and during gas production as well as the dusty and coarse-grained charcoal are carried along as abrasion. The coarse-grained charcoal ash with ash falls into the inclined part of the ash shaft 13 below the reactor. The ash and the coarse-grained Holzkohleabrieb is promoted and disposed of via a motor 19 operated with screw 18 in the gas-tight ash container 20.

To remedy disturbances in the charcoal bed by slag or Aschenansammlungen the flat lower part of the 8eckigen Wannenrostes 3 is designed to be movable with engine 12 or by hand.

For shielding against penetration of carburetor 2, the side channels 6 are protected by covers 16, as well as the gas outlet opening 14 of the gas outlet nozzle 25 is protected from the ingress of ash and carbon fiber by a cover 15.

The design of the steep bottle neck shape of the inner carburetor 2 through the refractory lining 9 prevents the otherwise feared bridging or cavitation by burnout, because the carburetor fuel rests directly on the 8eckigen Sink grid 3 for combustion and gasification or forced by gravity to nachzuschutschen. In addition, when introducing the lumpy carburetor fuel via the double slide lock 10, an additional drop pressure exerts, whereby bridging or cavitation are not given.

The bottleneck-shaped constriction over the pan grate also causes an intensive material flow changes, the homogeneous temperature distribution the pyrolysis gas and gasification gas mixture and the glowing charcoal as a reduction zone allows further cleavage of residual tars.

The internal circulation of the gas streams for splitting the hydrocarbons or tars additionally improves this process. As a result, an optimal temperature distribution in the reactor with a uniform complete sequence of the reactions and a sufficient residence time of the gases in the reaction zones is possible. These are the optimal conditions for stopping the reactions after the Boudouardian, water gas and methane equilibria to produce good gas quality and quantity.

In the following, some essential aspects of the present invention will be summarized in an overview. An essential aspect is that the apparatus of the reactor vessel 1 from a cylindrical steel jacket, a bottle neck refractory wall 9 of the carburetor chamber 2 with vertical side channels 6, a ring pipe 4 to the carburetor, designed as 8-jet nozzle ring with uniformly distributed diffuser injector 5 (injector) for sucking out the swelling pyrolysis gases 7 (conveying medium) by the gasification agent 4 (blowing medium) and producing a gas mixture 22 of both media and blowing the gas mixture (diffuser-printing energy effect) into the oxidation zone, a double-slide lock 10 for introducing the carburetor fuel into the gasifier space 2, which is burned or gassed in the drying, pyrolysis and oxidation zones and continuously formed by the stoichiometric combustion of the carburetor fuel in the 8-cornered trapezoidal furnace grid 3 is a charcoal lump as a reduction zone for gas production around the process, in which by the suction of the rising Schwell- and pyrolysis gases from the gasifier chamber 7 via the vertical side channels 6 of the refractory lining 9 of the reactor and the injection 5 of the gas mixture formed in this case 22 with the gasification agent 4 via the diffuser injector nozzles ( Fig. 3 ), forcibly an internal circulation of the gases in the reactor is effected, which at the same time achieved an intensive turbulence of the gas mixture 22 when blowing into the oxidation zone with the effect of the diffuser injector nozzles 5 and thus to a complete combustion of the tar-containing gas mixture 22 or cracking of the tars or long-chain hydrocarbon chains leads.

Furthermore, it is essential that with the device of Injektorförderung Fig. 3 , designed as a blowing nozzle 5 (propellant gasification agent), the Schwell- and pyrolysis gases 7 (pumped medium) sucked with vacuum effect and the resulting gas mixture 22 (gasification agent and pumped medium) is injected in the diffuser 5 with pressure energy in the oxidation zone and thus by the Injektorförderwirkung an internal circulation of the gases over the individual zones of drying, pyrolysis and oxidation is set in motion, avoiding gas leakage in the fuel supply and at the same time by intensive combustion with turbulence a homogeneous temperature distribution and intensive flow of gases in the reactor a sufficient residence time of the gases is achieved for further decomposition of the unburned hydrocarbon compounds or tars.

Another important feature is that the device of a nozzle ring 4, 5 (FIG. Fig. 2 ) is arranged evenly distributed around the gasification reactor with at least eight injector injection nozzles 5, which is connected to a ring pipe 4 lying outside the reactor and a centrally connected preheated gasification leads, in which the gas mixture 22 with the Schwell- and pyrolysis gases in the middle of Oxidation zone is injected into the carburetor and a controllable safety technology is ensured by this design.

It is particularly preferred if the device of a spacious 8eckigen oblique trapezoidal Feuerungsrostes with slot openings in the form of a trough 3 is centrally located in the middle of the gasification reactor, a movable base of the Feuerungsrostes by hand or motor 12 to eliminate interference from slag and Aschenansammlungen in which in comparison to the oxidation and pyrolysis zone, a proportionally oversized amount of a glowing charcoal cane is upstream as a reduction zone, which renews continuously by substoichiometric combustion of the carburetor fuel and thus as a catalyst a largely perfect reduction of the oxidation products (CO2, H2O) to produce a almost tarry product gas (CO, H2, CH4).

Furthermore, it is advantageous if the device of an ash shaft 13 in the lower part of the carburetor below the tub grid 3 fulfills the task of receiving the ash or carbon abrasion caused by the combustion of the carburetor fuel in the Wannerost 3 or by the abrasion caused by the suction of the Product gas in the vacuum mode by the slot-shaped Wannerost 3 falls on the underlying ash shaft 13 and is disposed of continuously via an ash screw 18 with motor drive 19 in the gas-tight ash container 20.

It is recommended that the device is a largely airtight fire-proof double-slider lock 10 with motor drive, the feed of the gasification reactor with carburetor fuel, which is on the removable Cover 23, 24 of the steel cylinder is placed and the lower slide lock against radiation of hot gases with a fire-resistant, movable plate 11 is shielded.

Furthermore, it is advantageous that the device for gasification reactor Fig. 1 from servicetechnischen reasons in three constructive components can be dismantled, namely an upper part with the cover 24 and double slide lock 10, a middle part of a sheet steel cylinder ring 1 with a refractory lining 9 in bottle neck shape 17 and integrated vertical side channels 6 and a lower part in which the diffuser Injector-Einblasdüsen 5 with the ring pipe network 4, 8eckigen Wannerost 3, the connected ash shaft 13 with gas outlet nozzle 14, 25 and ash removal 18, 19, 20 and all components form a unit.

Another aspect of the invention is that the device of the inner lining 9 of the reactor space is designed in the shape of a bottle neck, are integrated in the vertical side channels for the internal circulation of gases in the vacuum operation, rests on the 8eckigen Sink grid 3 and thereby an intensive material flow change for a homogeneous temperature distribution, which prevents bridging and the burning out of cavities.

Furthermore, it is important that the apparatus for the gasification reactor 1 ( Fig. 1 . Fig. 2 ) is worn uniformly fixed at four points 26 for servicing technical reasons on a square steel frame 21 and to which the mechanical equipment are attached.

In summary, the invention relates to an autothermic vacuum-operated fixed-bed DC gasifier with internal gas circulation for producing a virtually tar-free wood gas from biomass with the devices according to FIG Fig. 1 , a reactor chamber 2 with bottle neck lining 9 and integrated vertical side channels 6, a double slide lock 10 for introducing the carburetor fuel and an injector consisting of a at least 8-jet diffuser-injector nozzle ring 4, 5 for sucking and mixing the swelling and pyrolysis gases 7 with the gasification agent 5, the gas mixture 22 injected with pressure into the oxidation zone, the nozzle ring with a pipe ring outside the carburetor connected to preheated carburetor supplied, a proportionally oversized 8eckigen Wannenrostes 3 for receiving the charcoal embers as a reduction zone for sufficient gas reduction.

On the basis of these devices, the process of internally circulating the swelling and pyrolysis gases 7 with the gasification agent 4 through the injector conveyor sucks, mixes and injects the gas mixture into the oxidation zone for co-combustion with the gasoline fuel, thereby cracking the tars or hydrocarbons. a uniform temperature distribution, sufficient residence time is given for a complete reduction of gas in the reduction zone in the spacious pan grate.

Claims (10)

1. Device for gasification of solid fuels, in particular of biomass, in the form of an autothermal parallel-flow fixed-bed gasifier that works in a vacuum, having a fixed-bed reactor which has a reactor chamber (2) having an upper section (2a) as an oxidation zone and a lower section (2b) as a reduction zone, wherein diffusor injector nozzles (5) for injecting gasification agent (4) are provided, which are arranged between the upper section (2a) and the lower section (2b) in a central region of the reactor chamber (2), and wherein at least one upper outlet opening is provided in the upper section, which is connected to at least one return feed opening (22) in the central region of the reactor chamber (2), wherein the diffuser injector nozzles (5) for injecting gasification agent lead to the at least one return feed opening (22), and at least one lower outlet opening is provided in the lower section, characterised in that the at least one upper outlet opening is connected to the at least one return feed opening (22) in the central region of the reactor chamber (2) via internal vertical side channels in the fixed-bed reactor; and the upper outlet opening is exclusively connected to the at least one return feed opening (22).
2. Device according to claim 1, characterised in that the diffuser injector nozzles (5) are arranged to be evenly distributed around the periphery of the reactor chamber in the form of a nozzle ring.
3. Device according to any one of claims 1 or 2, characterised in that the lower section of the reactor chamber is formed as a preferably octagonal trough grate (3).
4. Device according to any one of claims 1 to 3, characterised in that the upper outlet opening is connected to the at least one return feed opening (22) via side channels (6) which are arranged within a cylindrical sheet steel casing and outside a fire-resistant brick lining (9).
5. Device according to any one of claims 1 to 4, characterised in that an ash chute (13) to receive solid residue is arranged below the trough grate (3), said ash chute being connected to a gas-tight ash pan (20) via an ash conveyor (18).
6. Device according to any one of claims 1 to 5, characterised in that the supply of the reactor chamber (2) with fuel occurs via a double gate valve (10).
7. Device according to any one of claims 1 to 6, characterised in that a brick lining (9) of the reactor chamber (2) is formed to be bottleneck-shaped.
8. Method for gasification of solid fuels, in particular of biomass, in an autothermal parallel-flow fixed-bed gasifier that works in a vacuum according to any one of claims 1 to 7, in which a gasification agent, preferably air, is injected into a central section of a reactor chamber (2) of a fixed-bed reactor and in which a first partial flow of the injected gas is guided upwards in a counter flow and removed from the fixed-bed reactor as a pyrolysis gas (7) and in which a second partial flow of the injected gas is guided downwards in a parallel flow and is removed from the fixed-bed reactor, characterised in that the first partial flow (7) is guided downwards in the fixed-bed reactor outside the reactor chamber (2) via internal vertical side channels and is introduced again into the reactor chamber (2) together with the gasification agent (4), wherein the first partial flow is returned into the fixed-bed reactor through the injector effect of the gasification agent (4) and wherein the diffuser injector nozzles cause a constant, internal circulation of the gas flows in the reactor by suctioning, mixing and injecting the media.
9. Method according to claim 8, characterised in that the pyrolysis gas (7) of the first partial flow is completely returned into the fixed-bed reactor.
10. Method according to any one of claims 8 or 9, characterised in that the gasification agent (4) is preheated before the injection into the fixed-bed reactor.

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