DE2926034A1 - Fluidised bed gasifier - with separate central gasification chamber for cyclone separated fuel particles - Google Patents

Abstract

Gas is produced from solid fuels in a fluidised bed above a fixed bed; particles sepd. from the raw gas by a cyclone are gasified in a separate generator zone and the prods. of the reaction introduced in the fluidised bed, according to the Parent Patent No. 2742222. These particles are collected in a central cylinder and passed in the separate zone by Venturi nozzles carrying a gasifying medium (recirculated raw gas) and directed secantially inward, where oxygen is injected centrally. This improves the gasification of the sepd. particles by intensive mixing and longer distances available for the reactions.

Description

Production of gas from solid fuels

Addition to patent ..... (patent application P 27 42 222,6-24) The invention relates to a method for generating gas from solid fuels according to the generic term of claim 1 and in particular in such A device that can be used for the gasification of deposited in a cyclone Particles.

In the process for generating gas specified in the main patent a fluidized bed is provided from solid fuels.

The gases rising from this fluidized bed contain solid particles, which are separated in a cyclone. These particles are after leaving of the cyclone gasified with the supply of gasifying agent, the resulting reaction products be directed towards the fluidized bed. A such procedure enables, among other things, a better utilization of the fuel supplied to the process as a whole Carbon, reduces the load on the gas flow and allows a favorable Implementation of the overall process.

The object of the invention is the method according to the main patent to be further improved and refined. This is especially true with regard to on the processes during the fermentation of the particles separated in the cyclone. Further the invention aims to provide an advantageous device for generating gas solid fuel gasification of separated in a cyclone Particles are created and formed inexpensively in the individual. With all of this in the Related other problems with which the invention is concerned arise from the respective explanation of the solution shown.

The invention provides that the particles separated in the cyclone accumulated and from this accumulation by means of a gaseous conveying medium in the area for the gasification of the particles with the generation of an at least partially rotative movement or circulation movement can be transported in this area and that oxygen is introduced into the gasification area in a spatially separated manner from the conveying medium will. This results in a particularly favorable process in the gasification area of the Particle reactions achieved. Through the rotation or circulation movement will extends the path of the particles within the gasification area, so that a particularly intensive mixing with reactants occurs.

For this purpose, the conveying medium is advantageous with the from it absorbed particles introduced essentially secantially into the gasification area. The oxygen supply can in particular take place centrally.

All suitable or suitable for the gasification process are used as the conveying medium required gaseous substances, e.g. C02, water vapor or fuel gas can be of any composition. It is particularly advantageous to the generated To take a recirculation amount of product gas, expediently after a gas cleaning, and this gas, if necessary.

to be used as a pumping medium after appropriate compression. That Product gas generated in the overall process exists in particular, depending on how the process is conducted mainly from hydrogen and carbon monoxide. This then also applies to the one used Recirculation gas. The use of a recirculation gas has the advantage that it is not reactive to the atmosphere of the cyclone and the process (quasi inert) is to be considered. There are no reactions when flowing into these rooms because it has approximately the same analysis. One as a conveying medium for the recirculation gas used in the cyclone separated particles can be advantageous Steam and / or carbon dioxide are added.

The one loaded with the solid particles picked up from the cyclone The conveying medium, in particular recirculation gas, reaches the separate gasification area, where the oxygen is injected, which spontaneously exothermes with part of the gas reacts, so that so much heat is released that a Can set temperature from 16000C to 18000C. This temperature can be over the amount of oxygen supplied and / or via the supply of certain amounts of Control the inert gas or water vapor in the pumped medium or in addition to it very precisely.

The amount of oxygen introduced into the gasification area becomes if the method is expediently carried out, this is substoichiometric (A < 1) compared to the amount of gas offered. It is then guaranteed that a complete conversion of the oxygen always occurs and the theoretical Combustion temperature of partial combustion with an oversupply of gas, especially gasification agent, is cooled down.

Due to the high temperature in the area of the explained combustion and gasification processes, the ash components are in the liquid phase state brought. Through a secantial injection of the conveying medium loaded with the particles, in particular of the recirculation gas, in the gasification area, the already Liquefied slag droplets are set in a rotating motion and by centrifugal forces carried to the wall of the gassing chamber.

The invention also provides, by means of a whole or at least delivery medium consisting almost entirely of gasification agent, in particular water vapor as much carbon particles as possible into the gasification area bring in and burn or gasify there.

This is particularly cheap. According to the invention, oxygen can then be used can also be introduced in stoichiometric or larger amounts.

An advantageous device with a cyclone and one associated with it Characterizes gasification chamber for the gasification of particles separated in the cyclone according to the invention in that the gasification chamber has at least one inlet for oxygen and at least one separate inlet for one with the im Contains cyclone-separated particles loaded conveying medium, with the introduction at least one connection for the delivery medium, at least one in the path of the delivery medium opening inlet for the separated particles and one essentially secantial having directed into the gasification chamber nozzle-like outlet.

The outlet of the cyclone is advantageously designed so that it the separated particles settle and then via as short a connection as possible, preferably directly into the inlet of one or more inlets. When the particles have to be conveyed into a chamber in which the pressure is essentially the pressure loss of the cyclone is higher than in the outlet of the latter, it must Conveying system for the particles to be able to overcome this pressure difference and at the same time to apply the kinetic energy for the transport of the particles. Suitable inlets for this can be designed in various ways, for example as an injector. In the case of a favorable training, the introduction is in the manner of a Venturi nozzle educated. A gas flow as a conveying medium experiences in the narrowest Place such a nozzle as a static pressure drop that the particles fall due to their gravity into the conveying gas flow and from there into the gasification chamber be transported.

The device can deal with the cyclone within a gas generation serving and a fluidized bed containing generator vessel be arranged. It but it is also possible to place the cyclone above or elsewhere outside of the Generator vessel to be arranged, but then at least the lower end of the Gasification chamber is located within the generator vessel or opens into the same, such that the resulting reaction products from the gasification chamber into the fluidized bed can enter.

Further details, features and advantages of the invention result from the following explanation, from the accompanying drawing and from the Claims. They show: FIG. 1 a generator in vertical longitudinal section with FIG Device according to the invention largely schematically, FIG. 2 which relates to the lower End of a cyclone adjoining part of the device, partly in section, Fig. 3 shows a section along the line III - III in FIG. 2 and FIG. 4 shows a detail Fig. 2 on a larger scale.

The generator according to FIG. 1 has a total reaction space R which surrounds it Generator vessel G, which has a fluidized bed gasification zone W and below it a Fixed bed gasification zone F contains. This means, ate in one and the same generator vessel G a fixed bed generator F and a fluidized bed generator W in connection with one another are provided.

The fixed bed gasification zone F for gasifying the fuel in dormant or quasi resting layer has the shape of a shaft and is with a rotating grate 4 known type equipped. With the number 5 are feed lines opening into the rotating grate for gasification agents (e.g. air or oxygen andtor water vapor, depending on the process to be carried out or the desired gas). For discharging the gasification residues A lock 6 of a known type is used from the fixed-bed gasification zone F.

In the fluidized bed gasification zone following the fixed bed gasification zone F W inlets 10 are provided for the fuel. The fuel entry devices each have a drivable screw conveyor 11, which the fuel of a supply is fed through a lock 13 of a known type. Instead of a screw conveyor can also be another device for introducing the fuel may be provided, e.g. a chute, a vibratory conveyor or the like.

Below the fuel inlets 10 are several, each ring-shaped Supply lines 14 distributed over the circumference for gasifying agents (e.g. air, Oxygen, water vapor). Their inlets opening into zone W are located at different heights, as can be seen from the drawing. This the fluidized bed gasification zone The part of the vessel G enclosing W has a particularly widening upward bin conical inner cross-section. The shape as well as the upper and lower end cross-section this part are chosen so that granular fuel with a given grain spectrum under the influence of the supplied gasification agent as well as that from the fixed bed gasification zone F rising gases are kept in the vortex.

The vessel G is closed and designed so that the gas generation can be carried out under increased internal pressure. But it can also be without increased Pressure to be worked. If only the latter comes into consideration, the Locks 6 and 13 are omitted or replaced by other devices.

A cyclone 60 is centrally located in the upper part of the generator vessel G arranged, which works in the usual way on the principle of centrifugal force and here for Separation of solid particles from the gas rising from the fluidized bed W is used.

There may be an inlet device, not shown, through which the gas laden with the particles enters the cyclone 60. That from the separated particles freed product gas leaves the generator through a outlet nozzles 24 arranged in the central axis of the cyclone 60.

Under the cyclone 60 is a device with a gasification chamber 70 arranged for the gasification of solid particles deposited in the cyclone 60 serves. These particles emerging from the lower end of the cyclone 60 collect in a settling space 61, which essentially has a rotationally symmetrical basic shape and occupies the space above the gasification chamber 70 or the head part surrounds the gasification chamber. The numeral 71 denotes pipes of a cooling system, to which a suitable coolant can be fed via an inlet 72, which flows through the pipes in the sense of the arrows shown in FIG. 2 and the system leaves via an outlet line 73. With the number 62 is a coolant inlet for a cooling system 63 belonging to the cyclone 60.

As can also be seen in FIG. 2, one is of a cooling jacket 65 with inlet and outlet for coolant, which are not specifically shown, for surrounding oxygen supply line 64 guided from above to the gasification chamber 70 and arranged centrally, i.e. they lies in the vertical longitudinal axis L of the substantially cylindrical in this embodiment Gasification chamber 70. The end of the oxygen supply line leads into the gasification chamber 70 extending head 66 with outlet openings 80 through which the oxygen in can reach the gasification chamber.

The solids coming out of the cyclone and accumulating in the settling room 61 Particles are distributed evenly over the circumference of the gasification chamber 70 arranged leads 74 introduced into the gasification chamber. With the one shown Embodiment, each introduction 74 is designed in the manner of a Venturi nozzle 78, whose axis 75 is directed secantially into the gasification chamber 70, as in particular Fig. 3 shows. In addition, the entries 74 are slightly from the horizontal inclined (Fig. 2).

The inlets 74 each have a connection 76 for a gaseous Conveying medium, in particular at least partially in the generator G itself generated gas, which is used as a recirculation gas. This recirculation gas is used in particular in the flow path behind a device, not shown Gas scrubbing taken into which the generator leaving through the outlet nozzle 24 The recirculation gas can also contain water vapor and / or carbon dioxide be added.

Each inlet 74 has an inlet 77 for the particles to be gasified on, which is at the narrowest point of the Venturi 78 is located and immediately with the overlying settling space 61 for the separated particles communicates.

In the gasification process taking place in the generator G, the blown in go Gasifying agents, e.g. water vapor and oxygen, are mixed with the introduced coal chemical reaction, in particular such that a gas is produced that predominantly consists of hydrogen and carbon monoxide. This gas emerges from the fluidized bed upwards W off and also takes in dusty form, depending on the exit speed Coal particles with. These are arranged in the cyclone above the fluidized bed W. 60 are deposited and collect in the settling space 61.

The hot dust separated in the cyclone, which is partly made up of coal and consists partly of ash and through the conveying medium through the inlets 74 is blown secantially into the gasification chamber 70, wherein it is a rotational movement is obtained by combustion with the supplied oxygen in a combustion zone of the supplied gas, namely recirculation gas, further heated at the same time and then enters into chemical reactions with the surrounding gas components. The oxygen reacts spontaneously exothermically with part of the gas blown in, sc ate itself in @er @ergasungskammer @@ Temperatures of for example the with The dust blown into the conveying medium is determined according to the local state variables and the composition of the gas phase partly burn directly, and that above in addition, the remaining portion is with the combustion products of the gas flame and if necessary, with excess steam according to the Boudouard reaction equation and the heterogeneous one Water gas equation implemented.

At the same time, the ash components turn into a liquid state brought. Due to the secantial injection of the pumped medium with the absorbed Dust in the gasification chamber 70 becomes not only the dust particles, but also sets the already liquefied slag droplets in a rotating motion, so that the slag drops to the wall of the gasification chamber by centrifugal forces are carried, on which they run down to a lower collecting channel 79. Latter has one or more not shown drainage openings from which the liquid Slag can drip down into the fluidized bed W, solidified on its way, through the Fluidized bed falls and is finally discharged in solid form. As a result of the high temperature gasification In the chamber 70 there are no dry ash particles from the gas flow from the fluidized bed W could be detected. and separated again in the cyclone would have to.

The outlet of the chamber 70 is directed towards the fluidized bed W.

This has the advantage, among other things, that the heat beam from the chamber 70 The fluidized bed also heats up.

Fig. 4 shows some details of the device on a larger scale recognize, including the one at the lower end of the oxygen supply line surrounded by the cooling jacket 65 64 located head 66. This is with, for example, twenty outlet openings 80 provided. These advantageously have a relatively small cross-section (e.g. a Diameter of a few millimeters), so that nozzle-like outlet paths result.

This is favorable for the formation of the flame in the gasification chamber 70. It can be achieved in this way that the oxygen at least when full Operation of the device and thus the corresponding amount at least at the speed of sound exit.

When putting the gasification chamber into operation it is initially useful A flammable gas is introduced as the conveying medium, which is released externally (e.g. in a with gas operated recuperator) to a temperature above the ignition temperature with oxygen Temperature has been heated up. The temperature of this fed to the gasification chamber The gas flow is measured and checked before it enters the chamber. Only when this gas stream has the predetermined temperature, the supply of oxygen to the Gasification chamber released.

Notwithstanding the embodiment shown, the generator can also only be designed as a fluidized bed generator (Winkler generator), in which case in Fig. 1, the lower part is to be imagined. In this case it is then below the fluidized bed one Suitable discharge device for the gasification residues is available, e.g. a liquid one Slag discharge.

For the structural design and the arrangement of the cyclone with There are various options for the post-gasification device. this is also valid for holding, supporting or suspending the cyclone in the generator and for the Arrangement and attachment of the lines for the various media. Stand for it suitable construction elements are available to those skilled in the art.

The invention also includes an embodiment in which the Cyclone is not arranged inside a generator, but outside of it Generator vessel is located. With such and similar designs, where the Gas stream rising from the fluidized bed through suitable conduits into the cyclone is initiated, but the gasification chamber is at least partially, advantageous but in their entirety, within the relevant generator vessel, in particular always in such a way that their exit is directed towards the fluidized bed.

All mentioned in the above description or in the drawing The features shown should, insofar as the known state of the art permits, on their own or also in combinations as falling under the invention -t ^ Jersen, L e r s e i t e

Claims (20)

Claims 1. A method for generating gas from solid fuels by gasifying with gasifying agents in a reaction space with a fluidized bed, wherein particles contained in the gas rising from the fluidized bed by means of a cyclone are separated, the separated particles after leaving the cyclone gasified with the supply of gasification agent in a separate gasification area and reaction products resulting from this gasification into the fluidized bed be initiated, according to patent ..... (patent application P 27 42 222.6-24), thereby characterized in that the particles deposited in the cyclone are collected and removed from this Accumulation by means of a gaseous conveying medium in the separate gasification area while generating an at least partially rotary movement or circulation movement be transported in this and that oxygen is spatially separated from the conveying medium is introduced into the gasification area. 2. The method according to claim 1, characterized in that the delivery medium with the particles taken up by it essentially secantially into the gasification area is introduced. 3. The method according to any one of claims 1 and 2, characterized in that that as a conveying medium at least partially a gas generated in the process as a recirculation gas is used. 4. The method according to any one of claims 1 to 3, characterized in that that water vapor is added to the pumped medium. 5. The method according to any one of claims 1 to 4, characterized in that that carbon dioxide is added to the pumped medium. 6. The method according to any one of claims 1 to 5, characterized in that that the amount of oxygen introduced into the gasification area versus the The amount of gas offered in the gasification area is set substoichiometrically. 7. The method according to any one of claims 1 to 5, characterized in that that by means of at least predominantly consisting of gasifying agent delivery medium Carbon particles introduced into the gasification area and burned in this or be gassed. 8, Apparatus for use in solid fuel gas generation by means of fluidized bed or fluidized bed and fixed bed gasification in one feed for the fuel and for gasifying agent having generator vessel, with a Cyclone for separating particles from the gas rising from the fluidized bed and with a gasification chamber assigned to the cyclone with gasifying agent feed line for the gasification of particles separated in the cyclone, in particular for implementation of the method according to one of claims 1 to 6, characterized in that the Gasification chamber (70) at least one inlet (64, 66) for oxygen and at least a separate inlet (74) for one with the separated in the cyclone (60) Contains particle-laden conveying medium, the introduction (74) at least one Connection (76) for the delivery medium, at least one opening into the path of the delivery medium Inlet (77) for the separated particles and one essentially secantial has outlet (78) directed into the gasification chamber (70). 9. Apparatus according to claim 8, characterized in that at several Inlets (74) these are distributed regularly over the circumference of the gasification chamber (70) are arranged. 10. Device according to one of claims 8 and 9, characterized in that that the introduction (74) below a settling space (61) for the separated Particles is arranged, the inlet (77) of the introduction (74) with the settling space (61) is related. 11. Device according to one of claims 8 to 10, characterized in that that the introduction (74) is arranged inclined relative to the horizontal. 12. Device according to one of claims 8 to 11, characterized in that that the introduction (74) is designed as a Venturi nozzle (78), the inlet (77) for the separated particles is located at the narrowest point of the Venturi nozzle. 13. Device according to one of claims 8 to 11, characterized in that that the introduction (74) is designed as an injector. 14. Device according to one of claims 8 to 13, characterized by one essentially in the region of the longitudinal center axis (L) of the gasification chamber (70) arranged oxygen inlet (64, 66). 15. Device according to one of claims 8 to 14, characterized by a head provided with several, relatively small outlet openings (80) (66) or the like. for introducing oxygen into the gasification chamber (70). 16. Device according to one of claims 8 to 15, characterized through an oxygen supply line leading from above to the gasification chamber (70) (64). 17. Device according to one of claims 8 to 16, characterized through an oxygen supply line (64) provided with cooling (65). 18. Device according to one of claims 8 to 17, characterized in that that at the lower end of the gasification chamber (70) a collecting channel (79) or the like. for Slag is provided. 19. Device according to one of claims 8 to 18, characterized in that that they in a known manner including the cyclone (60) within a Generator vessel (G) is arranged. 20. Device according to one of claims 8 to 18, characterized in that that at least the lower end of the gasification chamber (70) is within a generator vessel (G) is located while the cyclone is located outside the latter.