EP0247504B1 - Process for the production of gases containing hydrogen and carbon monoxide from solid fuels - Google Patents

Process for the production of gases containing hydrogen and carbon monoxide from solid fuels Download PDF

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Publication number
EP0247504B1
EP0247504B1 EP87107304A EP87107304A EP0247504B1 EP 0247504 B1 EP0247504 B1 EP 0247504B1 EP 87107304 A EP87107304 A EP 87107304A EP 87107304 A EP87107304 A EP 87107304A EP 0247504 B1 EP0247504 B1 EP 0247504B1
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EP
European Patent Office
Prior art keywords
gas
reactor
solid
gasification
recycling conduit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP87107304A
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German (de)
French (fr)
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EP0247504A3 (en
EP0247504A2 (en
Inventor
Johannes Dr. Ing. Dipl.-Ing. Lambertz
Wolfgang Dr. Ing. Dipl.-Ing. Adlhoch
Alfred Gustav Dipl.-Ing. Mittelstädt
Wolfgang Hermann
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Rheinbraun AG
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Rheinbraun AG
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Publication of EP0247504A3 publication Critical patent/EP0247504A3/en
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Classifications

    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/46—Gasification of granular or pulverulent flues in suspension
    • C10J3/54—Gasification of granular or pulverulent fuels by the Winkler technique, i.e. by fluidisation
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/46—Gasification of granular or pulverulent flues in suspension
    • C10J3/48—Apparatus; Plants
    • C10J3/482—Gasifiers with stationary fluidised bed
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/46—Gasification of granular or pulverulent flues in suspension
    • C10J3/48—Apparatus; Plants
    • C10J3/52—Ash-removing devices
    • C10J3/523—Ash-removing devices for gasifiers with stationary fluidised bed
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/46—Gasification of granular or pulverulent flues in suspension
    • C10J3/54—Gasification of granular or pulverulent fuels by the Winkler technique, i.e. by fluidisation
    • C10J3/56—Apparatus; Plants
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
    • C10K1/00—Purifying combustible gases containing carbon monoxide
    • C10K1/02—Dust removal
    • C10K1/026—Dust removal by centrifugal forces
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2200/00—Details of gasification apparatus
    • C10J2200/15—Details of feeding means
    • C10J2200/152—Nozzles or lances for introducing gas, liquids or suspensions
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2200/00—Details of gasification apparatus
    • C10J2200/15—Details of feeding means
    • C10J2200/158—Screws
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/18—Details of the gasification process, e.g. loops, autothermal operation
    • C10J2300/1807—Recycle loops, e.g. gas, solids, heating medium, water
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S48/00—Gas: heating and illuminating
    • Y10S48/04—Powdered fuel injection

Definitions

  • the invention relates to a process for producing hydrogen and carbon monoxide-containing gases from solid fuels at elevated pressure in a fluidized bed using gasifying agents, a fixed bed of solid gasification residues from which the solid gasification residues are drawn off possibly being located below the fluidized bed, and A post-gasification space is arranged above the fluidized bed and the synthesis gas generated is drawn off from the post-gasification space and passed through a separator in which at least some of the entrained solid particles are separated and returned to the fluidized bed via a return line, while the synthesis gas in at least the pre-cleaned state passes the separator leaves.
  • a gasification reactor which has a lower, conical part in which the fuel to be gasified is whirled up by the gasification agent.
  • the resulting fluidized bed within which the fuel particles are in constant motion, has a lower and an upper limit, which are normally not sharp.
  • the lower limit is formed by the fixed bed, which consists of finer and coarser, possibly sintered solid gasification residues.
  • the axis is withdrawn from the reactor.
  • the solid particles separated in the cyclone still contain so much carbon that it is worth returning them to the reactor.
  • an increased supply of gasification agents into the fluidized bed an operating state can even be reached which is referred to as a "circulating fluidized bed".
  • An upper limit of the fluidized bed is no longer formed. Rather, so much gasifying agent is supplied that the majority of the fuel particles enter the post-gasification chamber and from there into the separator and must therefore be recycled anyway if a sufficient degree of gasification is to be achieved.
  • the return line through which the particulate matter deposited in the cyclone is returned to the reactor extends between the cyclone, generally between the lower part thereof, and the reactor, the arrangement normally being such that the return line is in the region of the fluidized bed, that is, in the lower region of the reactor opens into this.
  • the return line runs obliquely at least in some areas, that is to say at an acute angle to the vertical. In any case, the interior of the reactor, the separator and the return line form a coherent system.
  • the risk that the solid matter in the return line gets stuck in it, with the result that after a short time the solid matter accumulating in the return line reaches the separator is particularly due to the fact that the return line has a small diameter in relation to its length .
  • the length will generally be determined by the distance to be bridged between the separator and the area of the fluidized bed reactor into which the solid to be returned is to be brought Distance.
  • An increase in the diameter of the return line, which would counteract the risk of blockages occurring, is ruled out, since this would undesirably influence the pressure and flow conditions in the overall device, possibly to a point at which the system does not more works.
  • a fluidized bed combustion device is known from SE-A 8 206 888, the flue gases of which are cleaned in a cyclone.
  • the dust separated in the cyclone is returned to the combustion device via a pneumatic transport system.
  • flue gas ducts that run parallel to a shaft within the combustion device, in the lower area of which the fluidized bed is located.
  • the flue gas ducts also serve as a collecting space for dust-like solids separated from the flue gases within the combustion device and deposited on the floor of the respective flue gas duct. This floor is provided with nozzles which are operated continuously or intermittently in order to return a certain amount of the dust into the fluidized bed in order to adjust the temperature of the same.
  • the invention has for its object to improve the process of the type described in the introduction so that, regardless of the amount of solid particles to be returned from the separator to the reactor, proper continuous operation of the gasification reactor is ensured.
  • the solid particles to be returned can be returned to the reactor in a controllable manner depending on the particular circumstances, that is to say on the gasification pressure, quantity and time.
  • the invention proposes that gas be introduced in pulses in the return line at least at one point to loosen up the solid particles therein.
  • a procedure has been found to be particularly expedient in which gas is blown into the return line at a plurality of points spaced apart in the longitudinal direction of the return line, these points should be arranged in the region in which the solid particles to be returned accumulate. It is therefore the area which is adjacent to the reactor or the fluidized bed located therein.
  • Some of the gas streams blown into the return line at different points can be blown continuously.
  • the pulsed blowing of at least some of the gas streams into the return line also has the advantage that less gas is used to achieve the same effect. This is also important because an excessively large amount of gas that is blown into the return line and that at least predominantly flows upwards towards the cyclone reduces the separation efficiency of the cyclone.
  • An mode of operation has been found to be expedient in which the gas is blown into the return line at the lowest, i.e. the mouth of the return line into the reactor, and the gas is blown into the return line intermittently, i.e. in pulses, at all other locations above it.
  • a mode of operation in which the pulse-like injection of the gas at the injection points is at least temporarily offset is particularly advantageous in such a way that from two injection points at a distance in the longitudinal direction of the return line, the injection begins earlier and possibly also at the injection point positioned closer to the reactor ends earlier than at the injection point positioned further away from the reactor. It is thereby achieved that the solid column located in the return line progressively loosens from bottom to top, that is to say counter to the direction of flow of the solid in the return line, which once leads to. that below the area of the solid column which has been loosened by a gas pulse at a certain position, the solid has also already been loosened, possibly already drained off.
  • the flow process within the return line can be influenced well in terms of quantity and time in this way, so that the speed at which the solid flows out of the return line into the reactor can be determined by controlling the gas pulses, in particular their time offset.
  • the amount of gas to be blown in may depend on the amount of the solid present in the return line or of the solid to be returned to the reactor.
  • the number of gas pulses can also depend on the amount of the solid in the return line or the solid to be returned to the reactor. It is possible to increase the amount of gas to be injected by increasing the number of gas pulses per unit of time, although this dependency is not mandatory, since it is readily possible to distribute a certain gas volume over a smaller or larger number of gas pulses. the gas volume injected per pulse then changes.
  • the duration of a pulse can be 0.1 to 2 s, preferably 1 s. In general, it is expedient to provide a pause between two successive pulses which lasts 1 s, preferably 0.1 s.
  • the time shift between the pulses of two adjacent blowing points can be so great that the pulse on the in each case in the chronological order second blowing point only begins after the pulse in the preceding blowing point has ended.
  • the amount of gas injected or the number of gas pulses can be controlled as a function of the temperature in the return line.
  • Inert gas e.g. B. Co 2 or nitrogen or recycled process gas can be used.
  • the gasification process for producing a product gas takes place in a reactor 10, in whose lower region 12, which tapers conically from top to bottom, is the fluidized bed 14.
  • the conical region is adjoined at the top by a cylindrical region 16 which contains the post-gasification zone 18.
  • the reactor 10 merges into a short shaft 20, at the end of which a conveyor and cooling screw 22 is arranged.
  • the solid gasification residues which predominantly contain ashes and collect in a fixed bed 24 below the fluidized bed 14, are drawn off through the shaft 20 and the screw 22.
  • the solid fuel to be gasified is introduced into the reactor 10 from a reservoir 28 by a screw 26. In the embodiment shown in the drawing, the solid fuel enters the latter below the upper limit 30 of the fluidized bed 14.
  • the fuel can e.g. B. pre-dried lignite, which has a water content of 12-18% and a grain size between 0 and 5 mm.
  • other carbon-containing fuels can also be used, e.g. Peat or coals that are more coalized than brown coal.
  • the reactor 10 is provided with a plurality of feed lines for gaseous media, which serve as gasifying agents.
  • the leads 32 located at the bottom open into the shaft 20 and serve to supply a gaseous medium to loosen the fixed bed 24.
  • This medium can be an endothermic gasifying agent, for example steam or CO 2 , but also an inert medium, for . B. nitrogen act.
  • nozzles are provided for the supply of gasification agent in planes which are at vertical distances from one another.
  • Gasification agent which brings about endothermic reactions is preferably supplied through the feed lines 34, 36 in the lower levels.
  • Oxygen-containing gasification agents are supplied in the feed lines 40, 41.
  • feed lines 44, 45 and 46 open into the after-reaction space 18. Gasification agents which bring about exothermic and endothermic reactions are normally introduced into the after-reaction space 18 via these feed lines.
  • the fuel to be gasified is introduced into the reactor 10 by the screw 26 in the region of the fluidized bed 14.
  • the fuel particles are fluidized by the gasification agents, the degassing products, the vapor produced by the evaporation of the water contained in the fuel and the reaction products.
  • the very small, almost dust-like components of the solid fuel introduced into the fluidized bed are entrained relatively quickly by the gas flowing upward through the upper boundary of the Wibel bed 30 into the after-reaction space 18, in which they are largely converted.
  • the extent to which gasification agents are fed through the feed lines 44, 45, 46 into the post-reaction space 18 depends in particular on the amount of solid carbon to be converted in the post-reaction space 18.
  • the heavy particles within the fluidized bed 14 sink through the latter and thus reach the fixed bed 24.
  • These heavier particles can be coarser, predominantly carbon-containing particles that are too large for the fluidized bed to move from below to the bottom gas flowing through the top could be carried.
  • such particles sediment down through the fluidized bed 14 onto the fixed bed 24, the weight of which is too high in relation to the grain size. It can be both carbon-containing particles with a high ash content and particles that consist exclusively of non-gasifiable substances.
  • the product gas 65 generated in the reactor 10 is withdrawn through a line 50 extending from the reactor 10 near the upper end thereof and, after pre-cleaning in a cyclone 52, downstream devices, e.g. B. supplied for gas cleaning.
  • the solid particles separated in the cyclone 52 which generally still contain carbon, pass via the lower outlet 66 of the cyclone into a return line 69, the lower, obliquely extending section 62 end 62 of which is connected to the reactor 10 in the region of the fluidized bed 14.
  • the gas 65 cleaned from the separated solid particles leaves cyclone 52 through a dip tube 67 via a line 68.
  • the return line 69 for the solid particles deposited in the cyclone 52 opens into the reactor 10 at about the level of the screw 26.
  • the solid particles flow downward from the lower region of the cyclone 66 into the return line 69, the cross section of which in the region 62 between the mouth 60 into the reactor 10 and about level 61 is filled by the solid particles.
  • the column of solid particles thus formed within the return line 69 constitutes a barrier which prevents solid particles and gas from the reactor 10 from passing through the return line 69 directly into the area of the separator 52 designed as a cyclone.
  • the return line 69 has a relatively small cross-section and, moreover, the pressure prevailing in the area of the cyclone 52 is noticeably lower than the pressure in the fluidized bed 14, so that a pressure gradient which counteracts gravity between the mouth 60 of the return line 69 into the reactor 10 on the one hand and the On the other hand, cyclone 52 exists, without special measures there is no guarantee that as much solid particles from the return line 69 will enter the reactor 10 over longer periods of time as will pass from the cyclone 52 into the return line above.
  • the small cross section of the return line 69 means that the particles contained therein can settle, so that even if a solid column formed in the return line 69, the height and weight of which is sufficient, the pressure drop to compensate for a proper and undisturbed outflow of the solid particles forming this column into the reactor 10 would not be guaranteed.
  • nozzles 81 opening into the return line 69 are provided for a gaseous medium. These nozzles 81 are arranged at intervals from one another in the longitudinal direction of the return line 69. They are fed via a control valve 70 to 77 from a common pressure medium source 78 with a gas, which can be, for example, C0 2 or also recirculated product gas which is branched off from the gas stream 65 at a suitable point.
  • the control valves 71-77 are operated by a common controller 79, to which they are connected via a line 80.
  • the pressure level of the gas 78 will be somewhat higher than the pressure level in the fluidized bed 14.
  • the controller 79 controls the individual valves 71 - 77 and in each case briefly releases a gas flow of a certain amount, which flows through the nozzles 81 into the lower region of the pulse Return line 69 arrives. It can be done in such a way that the valves 70-77 successively cause a short-term gas pulse such that a gas pulse is first passed through the valve 70 or the associated nozzle 81 into the mouth 60 of the return line 69 and then gas pulses are delayed by the others Valves are introduced into the return line 69, the time interval from the first gas pulse caused by the valve 70 increasing with increasing distance of the respective valve from the first valve 70.
  • valve 70 it is also possible to allow a longer pause to occur after actuation of the last valve 77 before the next pulse cycle begins by actuation of the valve 70. This depends on the amount of solid that comes from the cyclone 52 into the return line 69 and thus on the speed at which the solid particles from the return line 69 have to be introduced into the reactor 10. It is also possible, if necessary, not to allow the pulse cycle to run over the entire number of valves 70-77 present, but rather, for example, to only give gas pulses into return line 69 through valves 70-75. How the process is carried out depends on the particular circumstances, in particular the amount of solids collected in the return line 69 per unit of time.
  • the individual valves 70-77 can be actuated in a simple manner via the controller 79, to which the temperature sensors 57-59 detecting the temperature in the return line 69 are assigned, which are assigned to that region of the return line 69 in which the nozzles 81 of the valves 70 -77 are.
  • a temperature level is established within the latter which is not substantially below the temperature level within the fluidized bed 14 and usually in the range between 800 and 1000 ° C. If the return of the solid slows down, a direct drop in the temperature level to lower values can be determined at the temperature measuring points 57-59. This change in temperature indicates that the return of the solid from line 69 into fluidized bed 14 is too slow.
  • the controller is prompted to accelerate the pulse train by signals supplied to the controller 79 via the line 64 from the temperature measuring points.
  • the pulse train can be slowed down.
  • valves 70-77 or 71-77 instead of actuating the valves 70-77 or 71-77 via the temperature, there is also the possibility of actuating the valves and thus the gas pulses caused by them via the pressure prevailing at the respective points on the return line.
  • the nozzles 81 consist of customary, heat-resistant materials. Commercially available pneumatic switching valves can be used for valves 70 - 77. It is expedient to arrange them at equally large distances from and along the return line 69, it being possible to provide 1-3 nozzles / m of the return line.
  • the nozzles 81 will normally be arranged predominantly in the area of the return line which is not vertical.
  • the diameter of the return line 69 can be 20 cm, for example.
  • the amount of gas to be blown into the return line is small.
  • the quantitative ratio between this gas to be blown in and the product gas produced in the gasification reactor can be approximately 2: 500.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Combustion & Propulsion (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Devices And Processes Conducted In The Presence Of Fluids And Solid Particles (AREA)
  • Industrial Gases (AREA)
  • Fluidized-Bed Combustion And Resonant Combustion (AREA)

Description

Die Erfindung betrifft ein Verfahren zur Herstellung von Wasserstoff und Kohlenmonoxid enthaltenden Gasen aus festen Brennstoffen bei erhöhtem Druck in einem Wirbelbett unter Verwendung von Vergasungsmitteln, wobei sich unterhalb des Wirbelbetts ggf. ein Festbett aus festen Vergasungsrückständen befindet, aus welchem die festen Vergasungsrückstände abgezogen werden, und oberhalb des Wirbelbetts ein Nachvergasungsraum angeordnet ist und das erzeugte Synthesegas aus dem Nachvergasungsraum abgezogen und durch einen Abscheider geleitet wird, in welchem wenigstens ein Teil der mitgeführten Feststoffteilchen abgeschieden und über eine Rückführleitung in das Wirbelbett zurückgeführt wird, während das Synthesegas in zumindest vorgereinigtem Zustand den Abscheider verläßt.The invention relates to a process for producing hydrogen and carbon monoxide-containing gases from solid fuels at elevated pressure in a fluidized bed using gasifying agents, a fixed bed of solid gasification residues from which the solid gasification residues are drawn off possibly being located below the fluidized bed, and A post-gasification space is arranged above the fluidized bed and the synthesis gas generated is drawn off from the post-gasification space and passed through a separator in which at least some of the entrained solid particles are separated and returned to the fluidized bed via a return line, while the synthesis gas in at least the pre-cleaned state passes the separator leaves.

Zur Durchführung dieses Verfahrens wird im allgemeinen ein Vergasungsreaktor benutzt, der einen unteren, konischen Teil aufweist, in welchem der zu vergasende Brennstoff durch das Vergasungsmittel aufgewirbelt wird. Das so entstehende Wirbelbett, innerhalb dessen sich die Brennstoffteilchen in ständiger Bewegung befinden, hat eine untere und eine obere Grenze, die normalerweise nicht scharf ausgebildet sind. Die untere Grenze wird durch das Festbett gebildet, das aus feineren und gröberen, ggf. zusammengesinterten festen Vergasungsrückständen besteht. Am unteren Ende des Festbettes wird die Achse aus dem Reaktor abgezogen.To carry out this method, a gasification reactor is generally used which has a lower, conical part in which the fuel to be gasified is whirled up by the gasification agent. The resulting fluidized bed, within which the fuel particles are in constant motion, has a lower and an upper limit, which are normally not sharp. The lower limit is formed by the fixed bed, which consists of finer and coarser, possibly sintered solid gasification residues. At the lower end of the fixed bed, the axis is withdrawn from the reactor.

Aus der stark bewegten oberen Begrenzungsfläche des Wirbelbetts treten zusammen mit dem innerhalb des Wirbelbetts erzeugten Gas und ggf. überschüssigen Vergasungsmitteln Brennstoffteilchen aus. Diese Teilchen gelangen in einen den konischen, unteren Teil des Reaktors nach oben hin verlängernden, im allgemeinen zylindrischen Teil, innerhalb dessen sich die Nachvergasungszone befindet. In diese werden ebenfalls Vergasungsmittel eingeführt, um die aus dem Wirbelbett herausgerissenen Brennstoffteilchen noch möglichst weitgehend zu vergasen. Auch in der Nachvergasungszone befinden sich die Brennstoffteilchen und das erzeugte Gas in heftiger Bewegung, ohne daß jedoch alle Teilchen in das Wirbelbett zurücksinken. Vielmehr wird ein großer Anteil der Teilchen zusammen mit dem Produktgas am oberen Ende des Reaktors aus diesem ausgetragen. Diese Teilchen müssen in Abscheidem, die normalerweise als Zyklone ausgebildet sind, aus dem Produktgas abgeschieden werden.Fuel particles emerge from the strongly moving upper boundary surface of the fluidized bed together with the gas generated within the fluidized bed and any excess gasification agents. These particles enter a generally cylindrical part which extends the conical, lower part of the reactor upwards and within which the post-gasification zone is located. Gasification agents are also introduced into these in order to still gasify the fuel particles torn out of the fluidized bed as far as possible. The fuel particles and the gas produced are also in violent motion in the post-gasification zone, but without all of the particles sinking back into the fluidized bed. Rather, a large proportion of the particles are discharged together with the product gas at the upper end of the reactor. These particles have to be separated from the product gas in separators, which are normally designed as cyclones.

Die im Zyklon abgeschiedenen Feststoffteilchen enthalten noch soviel Kohlenstoff, daß sich deren Rückführung in den Reaktor lohnt. Bei vermehrter Zufuhr von Vergasungsmitteln in das Wirbelbett kann sogar ein Betriebszustand erreicht werden, der als "zirkulierende Wirbelschicht" bezeichnet wird. Dabei kommt es nicht mehr zur Ausbilding einer oberen Begrenzung des Wirbelbettes. Vielmehr wird soviel Vergasungsmittel zugeführt, daß die überwiegende Menge der Brennstoffteilchen in den Nachvergasungsraum und von da aus in den Abscheider gelangt und somit ohnehin zurückgeführt werden muß, wenn ein ausreichender Vergasungsgrad erzielt werden soll.The solid particles separated in the cyclone still contain so much carbon that it is worth returning them to the reactor. With an increased supply of gasification agents into the fluidized bed, an operating state can even be reached which is referred to as a "circulating fluidized bed". An upper limit of the fluidized bed is no longer formed. Rather, so much gasifying agent is supplied that the majority of the fuel particles enter the post-gasification chamber and from there into the separator and must therefore be recycled anyway if a sufficient degree of gasification is to be achieved.

Die Rückführleitung, durch die die im Zyklon abgeschiedenen Feststoffteilchen wieder in den Reaktor zurückgeführt werden, erstreckt sich zwischen dem Zyklon, und zwar im allgemeinen zwischen dem unteren Teil desselben, und dem Reaktor, wobei normalerweise die Anordnung so getroffen ist, daß die Rückführleitung im Bereich des Wirbelbetts, also im unteren Bereich des Reaktors in diesen mündet. Zur Überbrückung des horizontalen Abstands zwischen Abscheider und Reaktor verläuft die Rückführleitung wenigstens auf Teilbereichen schräg, also in einem spitzen Winkel zur Vertikalen. Jedenfalls bilden der Innenraum des Reaktors, der Abscheider und die Rückführleitung ein zusammenhängendes System.The return line through which the particulate matter deposited in the cyclone is returned to the reactor extends between the cyclone, generally between the lower part thereof, and the reactor, the arrangement normally being such that the return line is in the region of the fluidized bed, that is, in the lower region of the reactor opens into this. To bridge the horizontal distance between the separator and the reactor, the return line runs obliquely at least in some areas, that is to say at an acute angle to the vertical. In any case, the interior of the reactor, the separator and the return line form a coherent system.

Bei der Rückführung der Feststoffe ergeben sich Schwierigkeiten dadurch, daß in diesem System ein Druckgefälle vorhanden ist derart, daß der Druck innerhalb des Reaktors von unten nach oben, also in Richtung der strömende Gase, abnimmt. Ein weiteres Druckgefälle bildet sich innerhalb des Abscheiders aus, wobei der Druck im Abscheider in dem Bereich, an den sich die Rückführleitung für den abgeschiedenen Feststoff anschließt, noch einmal tiefer liegt als der Druck im oberen Bereich des Reaktors. Andererseits steht an dem dem Abscheider abgekehrten Ende der Rückführleitung, an welcher letztere in den unteren Bereich des Reaktors mündet, der dort herrschende Druck an der Rückführleitung an, so daß an beiden Enden der Rückführleitung unterschiedliche Drücke wirksam sind, wobei die beiden Bereiche unterschiedlichen Drucks durch den in der Rückführleitung sich sammelnden, in den Reaktor zurückzuführenden, Feststoff mehr oder weniger wirksam gegeneinander abgeschirmt sind. In der Praxis entstehen dabei unübersichtliche und nicht definierbare Betriebsverhältnisse innerhalb der Rückführleitung, die dazu führen, daß das Zurückfließen des im Abscheider abgetrennten Feststoffes in den Reaktor verhindert, zumindest jedoch beeinträchtigt wird. Es kann dadurch zu einer Verstopfung der Rückführleitung kommen, da sich die darin befindlichen Feststoffpartikel insbesondere in ihrem schräg verlaufenden Abschnitt festsetzen. Hinzu kommt, daß aufgrund des geschilderten Betriebszustandes unkontrollierbare und nicht beeinflußbare Druckausgleich-Vorgänge stattfinden, die ebenfalls zu Betriebsstörungen führen, ggf. sogar die Abscheideleistung des Abscheiders beeinträchtigen können.Difficulties arise when recycling the solids because there is a pressure drop in this system such that the pressure inside the reactor decreases from bottom to top, ie in the direction of the flowing gases. A further pressure drop forms within the separator, the pressure in the separator in the area to which the return line for the separated solid is connected being once again lower than the pressure in the upper area of the reactor. On the other hand, at the end of the return line facing away from the separator, at which the latter opens into the lower region of the reactor, the pressure prevailing there is present at the return line, so that different pressures are effective at both ends of the return line, the two regions being at different pressures the solid that collects in the return line and is to be returned to the reactor is more or less effectively shielded from one another. In practice, this creates confusing and indefinable operating conditions within the return line, which have the effect that the solids separated off in the separator flow back into the reactor, or at least are impaired. This can lead to a blockage of the return line, since the solid particles located therein become stuck, particularly in their sloping section. In addition, due to the described operating state, uncontrollable and uncontrollable pressure equalization processes take place, which also lead to malfunctions, possibly even impairing the separating performance of the separator.

Die Gefahr, daß der in der Rückführleitung befindliche Feststoff sich darin festsetzt mit dem Ergebnis, daß nach kurzer Zeit der in der Rückführleitung sich stauende Feststoff den Abscheider erreicht, ist insbesondere auch darauf zurückzuführen, daß die Rückführleitung einen kleinen Durchmesser im Verhältnis zu ihrer Länge aufweist. Die Länge wird im allgemeinen bestimmt sein durch die zwischen Abscheider und dem Bereich des Wirbelschichtreaktors, in den hinein der rückzuführende Feststoff gebracht werden soll, zu überbrückende Entfernung. Eine Vergrößerung des Durchmessers der Rückführleitung, die der Gefahr des Auftretens von Verstopfungen entgegenwirken würde, scheidet aus, da dadurch die Druck- und Strömungsverhältnisse in der Gesamteinrichtung in unerwünschter Weise beeinflußt würden, und zwar ggf. bis zu einem Punkt, an welchem das System nicht mehr arbeitet. Eine Vergrößerung des Durchmessers der Rückführleitung, die, wie bereits erwähnt, im allgemeinen im unteren Bereich des Reaktors in diesen einmündet, würde - bei gegebenem Reaktor-Durchmesser - dazu führen, daß ein größerer Anteil des gasförmigen Wirbelmediums, ggf. mit Feststoffteilchen, in den unteren Bereich der Rückführleitung eintritt, so daß die Strömungsverhältnisse, die eine Strömungsrichtung im Reaktor von unten nach oben, von dort in die Verbindungsleitung zum Abscheider und von dort über die Rückführleitung zurück in den unteren Bereich des Reaktors bewirken sollen, mit zunehmendem Durchmesser der Rückführleitung ggf. eine Umkehrung, jedenfalls eine Beeinflussung erführen, die einen geordneten Betrieb ausschlössen. D. h., daß die Rückführleitung in Anbetracht der vorbeschriebenen Gegebenheiten einen kleinen Durchmesser mit einem entsprechend hohen Strömungswiderstand aufweisen muß, um als eine Art Drossel zu wirken, die verhindert, daß ein Druckausgleich zwischen unterem Teil des Reaktors und Abscheider stattfindet.The risk that the solid matter in the return line gets stuck in it, with the result that after a short time the solid matter accumulating in the return line reaches the separator is particularly due to the fact that the return line has a small diameter in relation to its length . The length will generally be determined by the distance to be bridged between the separator and the area of the fluidized bed reactor into which the solid to be returned is to be brought Distance. An increase in the diameter of the return line, which would counteract the risk of blockages occurring, is ruled out, since this would undesirably influence the pressure and flow conditions in the overall device, possibly to a point at which the system does not more works. An increase in the diameter of the return line, which, as already mentioned, generally opens into the lower region of the reactor, would - given the reactor diameter - lead to a larger proportion of the gaseous fluidizing medium, possibly with solid particles, in the enters the lower area of the return line, so that the flow conditions, which should cause a flow direction in the reactor from bottom to top, from there into the connecting line to the separator and from there via the return line back to the lower area of the reactor, with increasing diameter of the return line, if necessary make a reversal, or at least an influence, which precludes orderly operation. This means that the return line must have a small diameter with a correspondingly high flow resistance in view of the above-described circumstances in order to act as a type of throttle which prevents pressure equalization between the lower part of the reactor and the separator.

Da die absolute Größe des Druckgefälles im System mit zunehmendem Druck innerhalb des Reaktors zunimmt, sind die Auswirkungen des Druckgefälles auf das aus dem Abscheider in den Reaktor rückzuführende Material bei modernen Vergasungsreaktoren, die unter einem Überdruck von 20 bar und mehr betrieben werden, entsprechend groß.Since the absolute size of the pressure drop in the system increases with increasing pressure inside the reactor, the effects of the pressure drop on the material to be returned from the separator to the reactor are correspondingly large in modern gasification reactors which are operated under an overpressure of 20 bar and more.

Aus der US-A 3 840 353 sind zwar ein Verfahren und ein Vergasungsreaktor zum Herstellen von Wasserstoff und Kohlenmonoxid enthaltenden Gasen aus festen Brennstoffen in einem Wirbelbett unter Verwendung von Vergasungsmitteln bekannt, wobei in die Rückführleitung zwischen Abscheider und Wirbelbett Gas zur Auflockerung der darin befindlichen Feststoffteilchen eingeblasen wird, um so letztere in einem fluidisierten Zustand zu halten. Eine solche Verfahrensführung läßt jedoch das vorerwähnte Druckgefälle unberücksichtigt. Sie mag bei unter Normaldruck betriebenen Vergasungsreaktoren jedenfalls dann möglich sein, wenn besondere Vorkehrungen, z.B. in Form einer siphonartigen Ausgestaltung der Rückführleitung, getroffen sind. Bei unter Überdruck betriebenen Vergasungsreaktoren wäre ein solches kontinuierlich betriebenes Wirbelbett aufgrund des größeren Druckgefälles zwischen Abscheider und dem Innenraum des eigentlichen Vergasungsreaktors nicht aufrecht zu erhalten.From US-A 3 840 353 a method and a gasification reactor for producing hydrogen and carbon monoxide-containing gases from solid fuels in a fluidized bed using gasifying agents are known, with gas in the return line between separator and fluidized bed for loosening the solid particles therein is blown in so as to keep the latter in a fluidized state. However, such a procedure does not take into account the aforementioned pressure drop. In the case of gasification reactors operated under normal pressure, it may be possible in any case if special precautions, e.g. in the form of a siphon-like configuration of the return line. In the case of gasification reactors operated under excess pressure, such a continuously operated fluidized bed could not be maintained due to the greater pressure difference between the separator and the interior of the actual gasification reactor.

Ferner ist aus der SE-A 8 206 888 eine Wirbelbett-Verbrennungseinrichtung bekannt, deren Rauchgase in einem Zyklon gereinigt werden. Der im Zyklon abgeschiedene Staub wird über ein pneumatisches Transportsystem in die Verbrennungseinrichtung zurückgeführt. Ferner sind Rauchgaskanäle vorhanden, die innerhalb der Verbrennungseinrichtung parallel zu einem Schacht verlaufen, in dessen unterem Bereich sich das Wirbelbett befindet. Die Rauchgaskanäle dienen auch als Sammelraum für aus den Rauchgasen innerhalb der Verbrennungseinrichtung abgeschiedenen staubförmigen Feststoffen, die sich auf dem Boden des jeweiligen Rauchgaskanales ablagern. Dieser Boden ist mit Düsen versehen, die kontinuierlich oder intermittierend in Betrieb genommen werden, um eine bestimmte Menge des Staubes in das Wirbelbett zwecks Einstellung der Temperatur desselben zurückzuführen. Je größer die Staubmenge zur Einhaltung eines bestimmten Temperaturniveaus ist, desto größer ist die Anzahl der Düsen, die in Betrieb sind. Ferner sind Sperren vorgesehen, die verhindern, daß der sich im unteren Bereich der Rauchgaskanäle sammelnde Staub unkontrolliert in den Bereich des Wirbelbettes gelangt. Das durch die Düsen eingeblasene Gas dient somit im wesentlichen dazu, den Rückhalteeffekt dieser Sperren unwirksam zu machen. Ein mehr oder weniger gleichmäßiges Rückführen des bereits in der Verbrennungseinrichtung abgeschiedenen Staubes ist nicht vorgesehen, da das Rückführen zur Einstellung der Temperatur im Wirbelbett erfolgen soll. Die sich aus dem Druckgefälle ergebenden Probleme bei der Rückführung der im Zylklon abgeschiedenen Feststoffe werden in der Vorveröffentlichung nicht erwähnt.Furthermore, a fluidized bed combustion device is known from SE-A 8 206 888, the flue gases of which are cleaned in a cyclone. The dust separated in the cyclone is returned to the combustion device via a pneumatic transport system. There are also flue gas ducts that run parallel to a shaft within the combustion device, in the lower area of which the fluidized bed is located. The flue gas ducts also serve as a collecting space for dust-like solids separated from the flue gases within the combustion device and deposited on the floor of the respective flue gas duct. This floor is provided with nozzles which are operated continuously or intermittently in order to return a certain amount of the dust into the fluidized bed in order to adjust the temperature of the same. The greater the amount of dust to maintain a certain temperature level, the greater the number of nozzles that are in operation. Furthermore, barriers are provided which prevent the dust collecting in the lower region of the flue gas channels from reaching the region of the fluidized bed in an uncontrolled manner. The gas blown in through the nozzles thus essentially serves to render the retention effect of these barriers ineffective. A more or less uniform return of the dust already deposited in the combustion device is not provided, since the return should take place to adjust the temperature in the fluidized bed. The problems resulting from the pressure drop when recycling the solids separated in the cyclone are not mentioned in the prior publication.

Der Erfindung liegt die Aufgabe zugrunde, das Verfahren der einleitend beschriebenen Art so zu verbessern, daß unabhängig von der Menge der aus dem Abscheider in den Reaktor zurückzuführenden Feststoffteilchen ein einwandfreier Dauerbetrieb des Vergasungsreaktors gewährleistet ist. Dabei soll insbesondere vermieden werden, daß Feststoff und/oder Gas unmittelbar aus dem Wirbelbett in die Rückführleitung bis an den Abscheider gelangen, da, unabhängig von anderen Beeinträchtigungen des Betriebes, dadurch die Abscheidungsleistung des Abscheiders beeinträchtigt würde. Trotz des verhältnismäßig kleinen Querschnitts der Rückführleitung soll unter allen betrieblichen Umständen gewährleistet sein, daß die rückzuführenden Feststoffteilchen in Abhängigkeit von den jeweiligen Gegebenheiten, also ggf. von Vergasungsdruck, Menge und Zeit, steuerbar in den Reaktor zurückgeführt werden können.The invention has for its object to improve the process of the type described in the introduction so that, regardless of the amount of solid particles to be returned from the separator to the reactor, proper continuous operation of the gasification reactor is ensured. In particular, it should be avoided that solids and / or gas get directly from the fluidized bed into the return line to the separator, since the separating performance of the separator would be impaired, regardless of other impairments to the operation. Despite the relatively small cross-section of the return line, it should be ensured under all operational circumstances that the solid particles to be returned can be returned to the reactor in a controllable manner depending on the particular circumstances, that is to say on the gasification pressure, quantity and time.

Zur Lösung dieser Aufgabe schlägt die Erfindung vor, daß in die Rückführleitung an wenigstens einer Stelle zur Auflockerung der darin befindlichen Feststoffteilchen Gas impulsartig eingeführt wird. Als besonders zweckmäßig hat sich eine Verfahrensführung herausgestellt, bei welcher in die Rückführleitung an mehreren, in Längsrichtung der Rückführleitung Abstände voneinander aufweisenden Stellen Gas eingeblasen wird, wobei diese Stellen in jenem Bereich angeordnet sein sollten, in welchem sich die rückzuführenden Feststoffteilchen ansammeln. Es ist somit jener Bereich, der dem Reaktor bzw. dem darin befindlichen Wirbelbett benachbart ist.To achieve this object, the invention proposes that gas be introduced in pulses in the return line at least at one point to loosen up the solid particles therein. A procedure has been found to be particularly expedient in which gas is blown into the return line at a plurality of points spaced apart in the longitudinal direction of the return line, these points should be arranged in the region in which the solid particles to be returned accumulate. It is therefore the area which is adjacent to the reactor or the fluidized bed located therein.

Ein Teil der an unterschiedlichen Stellen in die Rückführleitung eingeblasenen Gasströme kann kontinuierlich eingeblasen werden. Das impulsartige Einblasen wenigstens eines Teils der Gasströme in die Rückführleitung hat auch den Vorteil, daß zur Erzielung der gleichen Wirkung weniger Gas verbraucht wird. Dies ist auch deshalb von Bedeutung, weil eine zu große, in die Rückführleitung eingeblasene Gasmenge, die zumindest überwiegend nach oben in Richtung auf den Zyklon strömt, die Abscheideleistung des Zyklons verringert. Als zweckmäßig hat sich eine Betriebsweise herausgestellt, bei welcher an der zuunterst, also der Mündung der Rückführleitung in den Reaktor benachbarten Einblasstelle das Gas kontinuierlich und an allen anderen, darüber in Abständen befindlichen Stellen das Gas stoßweise, also impulsartig in die Rückführleitung eingeblasen wird.Some of the gas streams blown into the return line at different points can be blown continuously. The pulsed blowing of at least some of the gas streams into the return line also has the advantage that less gas is used to achieve the same effect. This is also important because an excessively large amount of gas that is blown into the return line and that at least predominantly flows upwards towards the cyclone reduces the separation efficiency of the cyclone. An mode of operation has been found to be expedient in which the gas is blown into the return line at the lowest, i.e. the mouth of the return line into the reactor, and the gas is blown into the return line intermittently, i.e. in pulses, at all other locations above it.

Besonders vorteilhaft ist eine Betriebsweise, bei welcher zumindest zeitweilig das impulsartige Einblasen des Gases an den Einblasstellen zeitlich versetzt derart erfolgt, daß von zwei in Längsrichtung der Rückführleitung einen Abstand aufweisenden Einblasstellen an der jeweils näher am Reaktor positionierten Einblasstelle das Einblasen früher beginnt und ggf. auch früher endet als an der vom Reaktor weiter entfernt positionierten Einblasstelle. Dadurch wird erreicht, daß die in der Rückführleitung befindliche Feststoffsäule von unten nach oben fortschreitend, also entgegen der Fließrichtung des Feststoffes in der Rückführleitung, eine Auflockerung erfährt, die einmal dazu führt,. daß unterhalb des durch einen Gasimpuls an einer bestimmten Position aufgelockerten Bereichs der Feststoffsäule der Feststoff ebenfalls bereits aufgelockert, ggf. bereits abgeflossen ist. Zum anderen läßt sich auf diese Weise der Fließvorgang innerhalb der Rückführleitung bezüglich Menge und Zeit gut beeinflussen, so daß über die Steuerung der Gasimpulse, insbesondere auch deren zeitliche Versetzung die Geschwindigkeit bestimmt werden kann, mit der der Feststoff aus der Rückführleitung in den Reaktor abfließt. Dabei kann die Menge des einzublasenden Gases abhängig sein von der Menge des in der Rückführleitung vorhandenen bzw. des in den Reaktor rückzuführenden Feststoffes. Auch die Anzahl der Gasimpulse kann abhängig sein von der Menge des in der Rückführleitung befindlichen bzw. des in den Reaktor rückzuführenden Feststoffes. Dabei ist es mögich, die Menge des einzublasenden Gases durch die Erhöhung der Anzahl der Gasimpulse pro Zeiteinheit zu vergrößern, wenngleich diese Abhängigkeit nicht zwingend ist, da ohne weiteres die Möglichkeit besteht, ein bestimmtes Gasvolumen auf eine kleinere oder größere Anzahl von Gasimpulsen zu verteilen, wobei dann jeweils das pro Impuls eingeblasene Gasvolumen sich ändert.A mode of operation in which the pulse-like injection of the gas at the injection points is at least temporarily offset is particularly advantageous in such a way that from two injection points at a distance in the longitudinal direction of the return line, the injection begins earlier and possibly also at the injection point positioned closer to the reactor ends earlier than at the injection point positioned further away from the reactor. It is thereby achieved that the solid column located in the return line progressively loosens from bottom to top, that is to say counter to the direction of flow of the solid in the return line, which once leads to. that below the area of the solid column which has been loosened by a gas pulse at a certain position, the solid has also already been loosened, possibly already drained off. On the other hand, the flow process within the return line can be influenced well in terms of quantity and time in this way, so that the speed at which the solid flows out of the return line into the reactor can be determined by controlling the gas pulses, in particular their time offset. The amount of gas to be blown in may depend on the amount of the solid present in the return line or of the solid to be returned to the reactor. The number of gas pulses can also depend on the amount of the solid in the return line or the solid to be returned to the reactor. It is possible to increase the amount of gas to be injected by increasing the number of gas pulses per unit of time, although this dependency is not mandatory, since it is readily possible to distribute a certain gas volume over a smaller or larger number of gas pulses. the gas volume injected per pulse then changes.

Die Dauer eines Impulses kann 0,1 bis 2 s, vorzugsweise 1 s betragen. Im allgemeinen ist es zweckmäßig, zwischen zwei aufeinanderfolgenden Impulsen eine Pause vorzusehen, die 1 s, vorzugsweise 0,1 s dauert. Bei der vorerwähnten Steuerung der Impulse derart, daß das Einblasen an in Längsrichtung der Rückführleitung Abstände voneinander aufweisenden Einblasstellen im vorbeschriebenen Sinn zeitlich versetzt erfolgt, kann die Zeitverschiebung zwischen den Impulsen zweier benachbarter Einblasstellen so groß sein, daß der Impuls an der jeweils in der zeitlichen Reihenfolge zweiten Einblasstelle erst beginnt, nachdem der Impuls in der zeitlich davor liegende Einblasstelle beendet ist. Andererseits ist es auch möglich, die Impulse zeitlich einander mehr oder weniger überschneiden zu lassen.The duration of a pulse can be 0.1 to 2 s, preferably 1 s. In general, it is expedient to provide a pause between two successive pulses which lasts 1 s, preferably 0.1 s. In the case of the aforementioned control of the pulses in such a way that the blowing in at blowing points which are spaced apart in the longitudinal direction of the return line takes place at different times in the manner described above, the time shift between the pulses of two adjacent blowing points can be so great that the pulse on the in each case in the chronological order second blowing point only begins after the pulse in the preceding blowing point has ended. On the other hand, it is also possible to let the impulses overlap one another to a greater or lesser extent.

Die Steuerung der Menge des eingeblasenen Gases bzw. der Anzahl der Gasimpulse kann in Abhängigkeit von der Temperatur in der Rückführleitung erfolgen. Als Einblasgas kann Inertgas, z. B. Co2 oder Stickstoff oder rückgeführtes Prozeßgas verwendet werden.The amount of gas injected or the number of gas pulses can be controlled as a function of the temperature in the return line. Inert gas, e.g. B. Co 2 or nitrogen or recycled process gas can be used.

In der Zeichnung ist als Ausführungsbeispiel im Schema der Längsschnitt durch einen unter Überdruck arbeitenden Winkler-Wirbelbett-Reaktor dargestellt.In the drawing, the longitudinal section through a Winkler fluidized bed reactor working under positive pressure is shown as an exemplary embodiment in the schematic.

Der Vergasgungsprozeß zur Herstellung eines Produktgases, welches vor allem H2 und CO enthalten wird, läuft in einem Reaktor 10 ab, in dessen unterem, von oben nach unten konisch sich verjüngenden Bereich 12 sich das Wirbelbett 14 befindet. An den konischen Bereich schließt sich bei dem in der Zeichnung dargestellten Ausführungsbeispiel nach oben hin ein zylindrischer Bereich 16 an, der die Nachvergasungszone 18 enthält.The gasification process for producing a product gas, which mainly contains H 2 and CO, takes place in a reactor 10, in whose lower region 12, which tapers conically from top to bottom, is the fluidized bed 14. In the embodiment shown in the drawing, the conical region is adjoined at the top by a cylindrical region 16 which contains the post-gasification zone 18.

An seinem unteren Ende geht der Reaktor 10 in einen kurzen Schacht 20 über, an dessen Ende eine Förder- und Kühlschnecke 22 angeordnet ist. Durch den Schacht 20 und die Schnecke 22 werden die festen Vergasungsrückstände abgezogen, die überwiegend Asche enthalten und sich unterhalb des Wirbelbetts 14 in einem Festbett 24 sammeln.At its lower end, the reactor 10 merges into a short shaft 20, at the end of which a conveyor and cooling screw 22 is arranged. The solid gasification residues, which predominantly contain ashes and collect in a fixed bed 24 below the fluidized bed 14, are drawn off through the shaft 20 and the screw 22.

Der zu vergasende feste Brennstoff wird durch eine Schnecke 26 aus einem Vorratsbehälter 28 in den Reaktor 10 eingebracht. Bei dem in der Zeichnung dargestellten Ausführungsbeispiel tritt der feste Brennstoff unterhalb der oberen Begrenung 30 des Wirbelbettes 14 in letzteres ein. Bei dem Brennstoff kann es sich z. B. um vorgetrocknete Braunkohle, die einen Wassergehalt von 12 - 18% und eine Körnung zwischen 0 und 5 mm aufweist, handeln. Es sind jedoch auch andere kohlenstoffhaltige Brennstoffe verwendbar, z.b. Torf oder Kohlen, die höher inkohlt sind als Braunkohle.The solid fuel to be gasified is introduced into the reactor 10 from a reservoir 28 by a screw 26. In the embodiment shown in the drawing, the solid fuel enters the latter below the upper limit 30 of the fluidized bed 14. The fuel can e.g. B. pre-dried lignite, which has a water content of 12-18% and a grain size between 0 and 5 mm. However, other carbon-containing fuels can also be used, e.g. Peat or coals that are more coalized than brown coal.

Der Reaktor 10 ist mit mehreren Zuleitungen für gasförmige Medien, die als Vergasungsmittel dienen, versehen. Die am weitesten unten befindlichen Zuleitungen 32 münden in den Schacht 20 und dienen zur Zuführung eines gasförmige Mediums zur Auflockerung des Festbettes 24. Bei diesem Medium kann es sich um ein endothermes Vergasungsmittel, beispielsweise Dampf oder C02, aber auch um ein inertes Medium, z. B. Stickstoff, handeln.The reactor 10 is provided with a plurality of feed lines for gaseous media, which serve as gasifying agents. The leads 32 located at the bottom open into the shaft 20 and serve to supply a gaseous medium to loosen the fixed bed 24. This medium can be an endothermic gasifying agent, for example steam or CO 2 , but also an inert medium, for . B. nitrogen act.

In dem oberhalb des Schachtes 20 befindlichen konischen Bereich 12 des Reaktors 10 sind in vertikale Abstände voneinander aufweisenden Ebenen angeordnete Düsen für die Zuführung von Vergasungsmittel vorgesehen. Durch die Zuleitungen 34, 36 in den unteren Ebenen wird vorzugsweise endotherme Umsetzungen bewirkendes Vergasungsmittel zuführt. In den Zuleitungen 40, 41 werden sauerstoffhaltige Vergasungsmittel zugeführt.In the conical area 12 of the reactor 10 located above the shaft 20, nozzles are provided for the supply of gasification agent in planes which are at vertical distances from one another. Gasification agent which brings about endothermic reactions is preferably supplied through the feed lines 34, 36 in the lower levels. Oxygen-containing gasification agents are supplied in the feed lines 40, 41.

Weitere Zuleitungen 44, 45 und 46 münden in den Nachreaktionsraum 18. Über diese Zuleitungen werden normalerweise exotherme und endotherme Umsetzungen bewirkende Vergasungsmittel in den Nachreaktionsraum 18 eingeführt.Further feed lines 44, 45 and 46 open into the after-reaction space 18. Gasification agents which bring about exothermic and endothermic reactions are normally introduced into the after-reaction space 18 via these feed lines.

Der zu vergasende Brennstoff wird durch die Schnecke 26 im Bereich des Wirbelbettes 14 in den Reaktor 10 eingetragen. Im Wirbelbett 14 wird die Brennstoffpartikel durch die Vergasungsmittel, die Entgasungsprodukte, den durch Verdampfen des im Brennstoff enthaltenden Wasser entstehenden Dampf und die Umsetzungsprodukte fluidisiert. Die sehr kleinen, annähernd staubförmigen Bestandteile des in das Wirbelbett eingeführten festen Brennstoffs werden verhältnismäßig schnell durch das die obere Begrenzung des Wibelbettes 30 nach oben durchströmende Gas in den Nachreaktionsraum 18 mitgerissen, in welchem sie zu einem großen Teil umgesetzt werden. Das Ausmaß der Zuführung von Vergasungsmitteln durch die Zuleitungen 44, 45, 46 in den Nachreaktionsraum 18 hinein hängt insbesondere von der Menge des im Nachreaktionsraum 18 umzusetzenden festen Kohlenstoffs ab.The fuel to be gasified is introduced into the reactor 10 by the screw 26 in the region of the fluidized bed 14. In the fluidized bed 14, the fuel particles are fluidized by the gasification agents, the degassing products, the vapor produced by the evaporation of the water contained in the fuel and the reaction products. The very small, almost dust-like components of the solid fuel introduced into the fluidized bed are entrained relatively quickly by the gas flowing upward through the upper boundary of the Wibel bed 30 into the after-reaction space 18, in which they are largely converted. The extent to which gasification agents are fed through the feed lines 44, 45, 46 into the post-reaction space 18 depends in particular on the amount of solid carbon to be converted in the post-reaction space 18.

Die schweren Partikel innerhalb des Wirbelbettes 14 sinken durch letzteres hindurch und gelangen so in das Festbett 24. Bei diesen schwereren Partikeln kann es sich einmal um gröbere, überwiegend kohlenstoffhaltige Partikel handeln, die zu groß sind, als daß sie von dem das Wirbelbett von unten nach oben durchströmenden Gas getragen werden könnten. Zum anderen sedimentieren solche Partikel durch das Wirbelbett 14 hindurch nach unten auf das Festbett 24, deren Gewicht im Verhältnis zu Korngröße zu hoch ist. Es kann sich dabei sowohl um kohlenstoffhaltige Partikel mit hohem Aschegehalt als auch um Partikel handeln, die ausschließlich aus nicht vergasbaren Substanzen bestehen.The heavy particles within the fluidized bed 14 sink through the latter and thus reach the fixed bed 24. These heavier particles can be coarser, predominantly carbon-containing particles that are too large for the fluidized bed to move from below to the bottom gas flowing through the top could be carried. On the other hand, such particles sediment down through the fluidized bed 14 onto the fixed bed 24, the weight of which is too high in relation to the grain size. It can be both carbon-containing particles with a high ash content and particles that consist exclusively of non-gasifiable substances.

Das im Reaktor 10 erzeugte Produktgas 65 wird durch eine nahe dem oberen Ende des Reaktors 10 von diesem abgehende Leitung 50 abgezogen und, nach Vorreinigung in einem Zyklon 52, nachgeordneten Einrichtungen, z. B. für die Gasreinigung zugeführt. Die im Zyklon 52 abgeschiedenen Feststoffpartikel, die im allgemeinen noch Kohlenstoff enthalten, gelangen über den unteren Ausgang 66 des Zyklons in eine Rückführleitung 69, deren unterer schräg verlaufender Abschnitt 62 Ende 62 im Bereich des Wirbelbettes 14 mit dem Reaktor 10 verbunden ist. Das von den abgeschiedenen Feststoffteilchen gereinigte Gas 65 verläßt Zyklon 52 durch ein Tauchrohr 67 über eine Leitung 68.The product gas 65 generated in the reactor 10 is withdrawn through a line 50 extending from the reactor 10 near the upper end thereof and, after pre-cleaning in a cyclone 52, downstream devices, e.g. B. supplied for gas cleaning. The solid particles separated in the cyclone 52, which generally still contain carbon, pass via the lower outlet 66 of the cyclone into a return line 69, the lower, obliquely extending section 62 end 62 of which is connected to the reactor 10 in the region of the fluidized bed 14. The gas 65 cleaned from the separated solid particles leaves cyclone 52 through a dip tube 67 via a line 68.

Die Rückführleitung 69 für die im Zyklon 52 abgeschiedenen Feststoffteilchen mündet etwa in Höhe der Schnecke 26 in den Reaktor 10. Die Feststoffteilchen fließen aus dem unteren Bereich des Zyklons 66 nach unten in die Rückführleitung 69, deren Querschnitt im Bereich62 zwischen der Mündung 60 in den Reaktor 10 und etwa dem Niveau 61 von den Feststoffteilchen ausgefüllt ist. Die so innerhalb der Rückführleitung 69 sich bildende Säule aus Feststoffteilchen stellt eine Sperre dar, die es verhindert, daß aus dem Reaktor 10 Feststoffteilchen und Gas durch die Rückführleitung 69 direkt in dem Bereich des als Zyklon ausgebildeten Abscheiders 52 gelangen.The return line 69 for the solid particles deposited in the cyclone 52 opens into the reactor 10 at about the level of the screw 26. The solid particles flow downward from the lower region of the cyclone 66 into the return line 69, the cross section of which in the region 62 between the mouth 60 into the reactor 10 and about level 61 is filled by the solid particles. The column of solid particles thus formed within the return line 69 constitutes a barrier which prevents solid particles and gas from the reactor 10 from passing through the return line 69 directly into the area of the separator 52 designed as a cyclone.

Da die Rückführleitung 69 einen verhältnismäßig kleinen Querschnitt aufweist und zudem der im Bereich des Zyklons 52 herrschende Druck merklich geringer ist als der Druck im Wirbelbett 14, so daß ein der Schwerkraft entgegenwirkendes Druckgefälle zwischen der Mündung 60 der Rückführleitung 69 in den Reaktor 10 einerseits und dem Zyklon 52 andererseits existiert, ist ohne besondere Maßnahmen keine Gewähr dafür gegeben, daß über längere Zeiträume unten soviel Feststoffteilchen aus der Rückführleitung 69 in den Reaktor 10 eintreten, wie oben aus dem Zyklon 52 in die Rückführleitung gelangen. Unabhängig vom vorerwähnten Druckgefälle ist auch aufgrund des kleinen Querschnitts der Rückführleitung 69 damit zu rechnen, daß sich die darin befindlichen Partikel festsetzen, so daß selbst dann, wenn sich in der Rückführleitung 69 eine Feststoffsäule bildete, deren Höhe und somit deren Gewicht ausreicht, das Druckgefälle zu kompensieren, ein einwandfreies und ungestörtes Abfließen der diese Säule bildenden Feststoffteilchen in den Reaktor 10 nicht gewährleistet wäre.Since the return line 69 has a relatively small cross-section and, moreover, the pressure prevailing in the area of the cyclone 52 is noticeably lower than the pressure in the fluidized bed 14, so that a pressure gradient which counteracts gravity between the mouth 60 of the return line 69 into the reactor 10 on the one hand and the On the other hand, cyclone 52 exists, without special measures there is no guarantee that as much solid particles from the return line 69 will enter the reactor 10 over longer periods of time as will pass from the cyclone 52 into the return line above. Regardless of the above-mentioned pressure drop, the small cross section of the return line 69 means that the particles contained therein can settle, so that even if a solid column formed in the return line 69, the height and weight of which is sufficient, the pressure drop to compensate for a proper and undisturbed outflow of the solid particles forming this column into the reactor 10 would not be guaranteed.

Zur betriebsnotwendigen Rückführung der Feststoffteilchen aus der Rückführleitung 69 in den Reaktor 10 sind in die Rückführleitung 69 mündende Düsen 81 für ein gasförmiges Medium vorgesehen. Diese Düsen 81 sind in Längsrichtung der Rückführleitung 69 in Abständen voneinander angeordnet. Sie werden über zwischengeschaltete Steuerventile 70 bis 77 von einer gemeinsamen Druckmittelquelle 78 mit einem Gas gespeist, bei dem es sich beispielsweise um C02 oder auch um rückgeführtes Produktgas handeln kann, welches vom Gasstrom 65 an geeigneter Stelle abgezweigt wird. Die Steuerventile 71 - 77 werden von einem gemeinsamen Regler 79 betätigt, mit dem sie über eine Leitung 80 verbunden sind. Das Druckniveau des Gases 78 wird etwas höher sein als das Druckniveau im Wirbelbett 14. Der Regler 79 steuert die einzelnen Ventile 71 - 77 an und gibt dabei jeweils kurzzeitig einen Gasstrom von bestimmter Menge frei, der über die Düsen 81 impulsartig in den unteren Bereich der Rückführleitung 69 gelangt. Dabei kann so vorgegangen werden, daß die Ventile 70 - 77 aufeinanderfolgend derart einen kurzzeitigen Gasimpuls bewirken, daß zunächst ein Gasimpuls durch das Ventil 70 bzw. die zugeordnete Düse 81 in die Mündung 60 der Rückführleitung 69 gegeben wird und danach zeitlich versetzt Gasimpulse durch die anderen Ventile in die Rückführleitung 69 eingeführt werden, wobei der zeitliche Abstand vom ersten, durch das Ventil 70 bewirkten Gasimpuls mit zunehmender Entfernung des jeweiligen Ventils vom ersten Ventil 70 zunimmt. Dadurch wird der in der Rückführleitung 69 stehende Feststoff von unten nach oben fortschreitend aufgelockert, so daß die Partikel unter der Einwirkung ihres Gewichts nach unten strömen und in das Wirbelbett 14 gelangen, andererseits jedoch keine schlagartige Entleerung der Rückführleitung 69 erfolgt, so daß immer soviel Feststoff in letzterer verbleibt, daß dieser als Sperre gegenüber dem Innenraum des Reaktors 10 wirkt und somit verhindert wird, daß Gas und Feststoff aus dem Innenraum des Reaktors 10 direkt durch die Rückführleitung 69 in den Zyklon 52 gelangen.For the operationally necessary return of the solid particles from the return line 69 into the reactor 10, nozzles 81 opening into the return line 69 are provided for a gaseous medium. These nozzles 81 are arranged at intervals from one another in the longitudinal direction of the return line 69. They are fed via a control valve 70 to 77 from a common pressure medium source 78 with a gas, which can be, for example, C0 2 or also recirculated product gas which is branched off from the gas stream 65 at a suitable point. The control valves 71-77 are operated by a common controller 79, to which they are connected via a line 80. The pressure level of the gas 78 will be somewhat higher than the pressure level in the fluidized bed 14. The controller 79 controls the individual valves 71 - 77 and in each case briefly releases a gas flow of a certain amount, which flows through the nozzles 81 into the lower region of the pulse Return line 69 arrives. It can be done in such a way that the valves 70-77 successively cause a short-term gas pulse such that a gas pulse is first passed through the valve 70 or the associated nozzle 81 into the mouth 60 of the return line 69 and then gas pulses are delayed by the others Valves are introduced into the return line 69, the time interval from the first gas pulse caused by the valve 70 increasing with increasing distance of the respective valve from the first valve 70. As a result, the solids in the return line 69 are loosened progressively from bottom to top, so that the particles flow downward under the influence of their weight and get into the fluidized bed 14, but on the other hand there is no sudden emptying of the return line 69, so that always so much solids in the latter remains that it acts as a barrier to the interior of the reactor 10 and thus is prevented that gas and solid from the interior of the reactor 10 directly through the return line 69 into the cyclone 52.

Die vorstehend beschriebene Verfahrensweise kann in Abhängigkeit von der Menge des in die Rückführleitung 69 aus dem Zyklon 52 kommenden Festoffes so angewendet werden, daß, sobald der Gasimpuls durch das am weitesten oben befindliche Ventil 77 in die Rückführleitung 69 eingeführt worden ist, der Zyklus wieder von vorn mit einem durch das Ventil 70 eingeführten Gasimpuls beginnt.The procedure described above can be used, depending on the amount of solids coming into the return line 69 from the cyclone 52, such that once the gas pulse has been introduced into the return line 69 through the uppermost valve 77, the cycle resumes from starts with a gas pulse introduced through valve 70.

Es ist im Bedarfsfall auch möglich, nach Betätigung des letzten Ventils 77 zunächst eine größere Pause eintreten zu lassen, bevor der nächste Impulszyklus durch Betätigen des Ventils 70 beginnt. Dies hängt ab von der Menge des Feststoffes, der aus dem Zyklon 52 in die Rückführleitung 69 gelangt und somit von der Geschwindigkeit, mit welcher die Feststoffpartikel aus der Rückführleitung 69 in den Reaktor 10 eingeleitet werden müssen. Es ist auch möglich, im Bedarfsfall den Impulszyklus nicht über die gesamte Anzahl der vorhandenen Ventile 70 - 77 ablaufen zu lassen, sondern beispielsweise nur durch die Ventile 70 - 75 Gasimpulse in die Rückführleitung 69 zu geben. Wie im einzelnen verfahren wird, hängt von den jeweiligen Gegebenheiten, insbesondere der pro Zeiteinheit in der Rückführleitung 69 sich sammelnden Feststoffmenge ab.If necessary, it is also possible to allow a longer pause to occur after actuation of the last valve 77 before the next pulse cycle begins by actuation of the valve 70. This depends on the amount of solid that comes from the cyclone 52 into the return line 69 and thus on the speed at which the solid particles from the return line 69 have to be introduced into the reactor 10. It is also possible, if necessary, not to allow the pulse cycle to run over the entire number of valves 70-77 present, but rather, for example, to only give gas pulses into return line 69 through valves 70-75. How the process is carried out depends on the particular circumstances, in particular the amount of solids collected in the return line 69 per unit of time.

Die Betätigung der einzelnen Ventile 70 - 77 kann in einfacher Weise über den Regler 79 erfolgen, dem die Temperatur in der Rückführleitung 69 erfassende Temperaturfühler 57 - 59 zugeordnet sind, die jenem Bereich der Rückführleitung 69 zugeordnet sind, in welchem die Düsen 81 der Ventile 70 -77 sich befinden. Bei hohem Feststoffdurchsatz durch die Rückführleitung 69 stellt sich innerhalb derselben ein Temperaturniveau ein, welches nicht wesentlich unter dem Temperaturniveau innerhalb der Wirbelschicht 14 und üblicherweise im Bereich zwischen 800 und 1000° C liegt. Verlangsamt sich die Rückführung des Feststoffes, so ist an den Temperaturmeßstellen 57 - 59 ein unmittelbares Absinken des Temperaturniveaus auf niedrigere Werte feststellbar. Diese Änderung in der Temperatur läßt erkennen, daß die Rückführung des Feststoffes aus der Leitung 69 in das Wirbelbett 14 hinein zu langsam erfolgt. Durch über die Leitung 64 von den Temperaturmeßstellen dem Regler 79 zugeführte Signale wird der Regler veranlaßt, die Impulsfolge zu beschleunigen. Im umgekehrten Fall, also wenn weniger Feststoff aus dem Zyklon 52 zugeführt wird und demzufolge weniger Feststoff am unteren Ende der Rückführleitung 69 in das Wirbelbett abzuleiten ist, kann die Impulsfolge verlangsamt werden.The individual valves 70-77 can be actuated in a simple manner via the controller 79, to which the temperature sensors 57-59 detecting the temperature in the return line 69 are assigned, which are assigned to that region of the return line 69 in which the nozzles 81 of the valves 70 -77 are. With a high solids throughput through the return line 69, a temperature level is established within the latter which is not substantially below the temperature level within the fluidized bed 14 and usually in the range between 800 and 1000 ° C. If the return of the solid slows down, a direct drop in the temperature level to lower values can be determined at the temperature measuring points 57-59. This change in temperature indicates that the return of the solid from line 69 into fluidized bed 14 is too slow. The controller is prompted to accelerate the pulse train by signals supplied to the controller 79 via the line 64 from the temperature measuring points. In the opposite case, ie when less solids are fed from the cyclone 52 and consequently less solids are to be discharged into the fluidized bed at the lower end of the return line 69, the pulse train can be slowed down.

Abweichend von der vorbeschriebenen Betriebsweise ist es auch möglich, das untere Ventil 70 permanent in Offenstellung zu lassen, so daß kurz vor der Mündung 60 des Rückführrohres 62 in den Reaktor 10 ein kontinuierlicher Gasstrom in die Rückführleitung 69 eintritt.Deviating from the above-described operating mode, it is also possible to leave the lower valve 70 permanently in the open position, so that a continuous gas stream enters the return line 69 shortly before the mouth 60 of the return pipe 62 in the reactor 10.

Anstelle der Betätigung der Ventile 70 - 77 bzw. 71 - 77 über die Temperatur besteht auch die Möglichkeit, die Ventile und damit die durch diese bewirkten Gasimpulse über den an den jeweiligen Stellen der Rückführleitung herrschenden Druck zu zu betätigen. Welcher der beiden Möglichkeiten - Druck oder Temperatur - oder Vorzug gegeben wird, hängt von den jeweiligen betrieblichen Gegebenheiten ab. Die Düsen 81 bestehen aus üblichen hochwarmfesten Werkstoffen. Für die Ventile 70 - 77 können handelsübliche pneumatische Schaltventile verwendet werden. Ihre Anordnung in möglichst gleich großen Abständen von und entlang der Rückführleitung 69 ist zweckmäßig, wobei 1 - 3 Düsen/m Rückführleitung vorgesehen sein können. Die Düsen 81 werden normalerweise überwiegend in dem Bereich der Rückführleitung angeordnet sein, der nicht vertikal verläuft. Der Durchmesser der Rückführleitung 69 kann beispielsweise 20 cm betragen.Instead of actuating the valves 70-77 or 71-77 via the temperature, there is also the possibility of actuating the valves and thus the gas pulses caused by them via the pressure prevailing at the respective points on the return line. Which of the two options - pressure or temperature - or preference is given depends on the respective operational circumstances. The nozzles 81 consist of customary, heat-resistant materials. Commercially available pneumatic switching valves can be used for valves 70 - 77. It is expedient to arrange them at equally large distances from and along the return line 69, it being possible to provide 1-3 nozzles / m of the return line. The nozzles 81 will normally be arranged predominantly in the area of the return line which is not vertical. The diameter of the return line 69 can be 20 cm, for example.

Die Menge des in die Rückführleitung einzublasenden Gases ist gering. So kann das Mengenverhältnis zwischen diesem einzublasenden Gas und dem im Vergasungsreaktor hergestellte Produktgas etwa 2 : 500 betragen.The amount of gas to be blown into the return line is small. The quantitative ratio between this gas to be blown in and the product gas produced in the gasification reactor can be approximately 2: 500.

Claims (12)

1. A process for the production of gas containing hydrogen and carbon monoxide from solid fuels at elevated pressure in a fluidised bed using gasification agents, wherein beneath the fluidised bed there is possibly a solid bed of solid gasification residues, from which the solid gasification residues are drawn off, while arranged above the fluidised bed is a post-gasification space, and the gas produced is removed from the post-gasification space and passed through a separator in which at least a part of the entrained solid particles is separated off and returned to the reactor by way of a recycling conduit while the product gas leaves the separator in an at feast pre-cleaned condition, and gas is injected into the recycling conduit at at least one location for loosening up the solid particles to be found therein, characterised in that the gas is injected into the recycling conduit in a pulse-like manner.
2. A process according to claim 1, characterised in that gas is injected into the recycling conduit at a plurality of locations which are disposed at spacings from each other in the longitudinal direction of the recycling conduit and at least a portion of the gas flows is injected into the recycling conduit in a pulse-like manner.
3. A process according to claim 2, characterised in that the pulse-like injection of the gas at the injection locations occurs in displaced relationship in respect of time in such a way that, of two injection locations disposed at a spacing from each other in the longitudinal direction of the recycling conduit, injection of the gas at the respective injection location which is positioned closer to the reactor begins earlier than at the injection location which is positioned at a greater spacing from the reactor.
4. A process according to claim 1, characterised in that the amount of gas to be injected is dependent on the amount of solid material in the recycling conduit.
5. A process according to claim 2, characterised in that the number of gas pulses is dependent on the amount of solid material in the recycling conduit.
6. A process according to one of the preceding claims, characterised in that the duration of a pulse is 0.1 to 2 seconds, preferably 1 second.
7. A process according to one of the preceding claims, characterised in that there is a pause which is up to 1 second and preferably 0.1 second between two successive pulses.
8. A process according to one of the preceding claims, characterised in that control in respect of speed or amount of the injected gas or the number of gas pulses is effected in dependence on the temperature in the recycling conduit
9. A process according to claim 1, characterised in that an inert gas, for example C02, and/or recycled product gas, is injected into the recycling conduit.
10. A gasification reactor for producing a product gas containing hydrogen and carbon monoxide from solid fuels at elevated pressure using gasification agents with a fluidised bed, a solid material of solid gasification residues which is possibly disposed beneath the fluidised bed, a means for introducing the fuels into the reactor, a post-gasification space arranged above the fluidised bed, a separator for separating off at least a portion of the solid particles contained in the product gas, and a conduit for recycling the separated-off solid parti- des into the reactor, characterised in that at least in the region (62) of the recycling conduit (69) which adjoins the reactor (10) the recycling conduit (69) is provided with at least one injection nozzle (81) for a gas and means (79) for the pulse-like injection of the gas.
11. A gasification reactor according to claim 10, characterised in that there are provided a plurality of injection nozzles (81) which are at spacings from each other in the longitudinal direction of the recycling conduit (69) and connected into the feed conduits for the nozzles (81) are valves (70-77) which permit the gas flows to be injected into the recycling conduit (69) in a pulse-like manner.
12. A gasification reactor according to claim 10 or claim 11, characterised in that temperature sensors (57-59) for detecting the temperature in the recycling conduit (69) are provided and the injection nozzle or nozzles (81) is or are actuable in dependence on the temperature in the recycling conduit (69).
EP87107304A 1986-05-27 1987-05-19 Process for the production of gases containing hydrogen and carbon monoxide from solid fuels Expired - Lifetime EP0247504B1 (en)

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DE19863617802 DE3617802A1 (en) 1986-05-27 1986-05-27 METHOD FOR PRODUCING HYDROGEN AND CARBON MONOXIDE GASES FROM SOLID FUELS
DE3617802 1986-05-27

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DE3617802C2 (en) 1992-09-10
CN87103895A (en) 1987-12-16
FI872321A (en) 1987-11-28
EP0247504A3 (en) 1988-04-06
CN1011417B (en) 1991-01-30
FI86075C (en) 1992-07-10
ES2017959B3 (en) 1991-03-16
DE3765311D1 (en) 1990-11-08
EP0247504A2 (en) 1987-12-02
AU594463B2 (en) 1990-03-08
AU7331487A (en) 1987-12-03
DE3617802A1 (en) 1987-12-03
US4852994A (en) 1989-08-01
FI872321A0 (en) 1987-05-26
FI86075B (en) 1992-03-31
GR3001127T3 (en) 1992-06-25

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