DE4316869C1 - Process for gasifying solids and gasification reactor - Google Patents

Abstract

A gasification reactor having a shaft for gasifying solids, in particular residues, in which the solids are charged into a shaft, at least partially gasified with controlled substoichiometric feed of fresh air and the still incompletely gasified solids portions and gases are fed via at least one choke point of the shaft to a chamber in which the solids portions are subjected to secondary gasification and from which gases are taken off, a bed being formed from which ash is discharged is distinguished in that an inert fluidisable material which additionally contains organic constituents and a fluidising and reaction gas are introduced into the bed in an amount sufficient to generate a fluidised bed and in that the height of the fluidised layer of the fluidised bed is controlled to a preset level.

Description

The invention relates to a method for gasification and Ver burn solids, especially residues, with the Features of the preamble of claim 1 and one Gasification reactor with the features of the preamble of Claim 7.

Methods of this kind are complicated by the fact that the Verga solution of the solids to be burned, usually in pieces ge organic solids, such as wood, plastic, rubber, Packaging, textile, paper waste, e.g. B. in the form  of chops, pellets, briquettes or the like, for a very long time takes a lot compared to the previous degassing fold. In addition to this difficulty comes partial gasified solids, which via the constriction in the Chamber for further gasification have reached, partly in the ash bed that forms at the bottom of the chamber falls and from there burned incompletely with the ashes be. This worsens the gas yield. If the gasification process after the ash is discharged outside of the gasification reactor, gases are formed which due to the existing environmental protection regulations not without more can be drained into the environment.

In addition, these regulations must ensure that that organic components in residues to be deposited less than 5%.

In a known method and a known Verga solution reactor according to DE 39 24 626 C2 is used to avoid these disadvantages additionally air in the area of the ashes bed initiated, which is also of a movable Support in the form of a swivel around a horizontal axis prism is formed. In this way, in the Chamber below the constriction a complete combustion of only partially gasified and burned solid matter len can be achieved. The long gasification time can go through these measures, however, can hardly be shortened, and the gas out Prey does not usually improve because of the Solids driven gas is not discharged but burned on the spot. In addition, such known "descending" working method, in which the Solids and the air introduced from top to bottom flow, a bad "burnout" known, so that in the removed ash still unburned residual portions of the Solid matter is included, which is disposed of at a landfill  Need to become.

The known construction also calls for both the space requirement as well as the structural design considerable effort.

The invention has for its object a method and a gasification reactor of the type described above train that with a more compact design, the time the gasification shortened considerably and at the same time the Yield of gasification can be optimized.

A method according to the patent serves to solve this problem claim 1.

A gasification reactor according to the invention stands out by the features of claim 7.

With the method according to the invention it is achieved that in the bed fallen, not yet fully gassed or burned solids by means of the fluidizing and Reaction gas in the fluidized bed formed according to the invention brought into limbo and gas on all sides be enveloped. By the reaction gas, which Sauer Contains substances, such solids in a time period shortened many times over gasified, which reaches up to the (short) degassing time, as if the solids in a solid bed or would be in the ash bed. The gasification rate and the The yield of gases is significantly improved. The produced gases, as is known in the process removed from the gasification reactor according to the invention and in a separate combustion process to produce Burned useful heat. Alternatively, you can at least partially back into the shaft to support the removal and  Gasification of the solids are introduced.

In the invention, the unburned residual portions are in a negligible size. Surrender therefore no environmental problems, because only from Koh free ash and pollutants is to be disposed of.

In a first embodiment of the method according to Invention is the fluidizing chamber or a fluidized bed in the Shaft designed in-house, namely in the ash bed. At a The second embodiment of the invention is the fluidizing chamber trained separately below or next to the shaft. In a gasification reactor according to the invention is in this Fall the duct through a wall from the fluidizing space separated, which can run horizontally and then one Partition represents, or vertically from a side wall of the Shaft can be formed, then a passage to Connection of the fluidizing space divided into subspaces is left.

Further embodiments of the invention are in the Unteran protected.

The invention is based on the schematic drawing Solutions to exemplary embodiments with further details explained in more detail. Show it:

Fig. 1 to 5 five variants of the gasification reactor according to the invention in vertical section, the unit for the sake of bleaching or equivalent construction parts or assemblies the same reference numerals are used and

Fig. 6 is a longitudinal section through a nozzle tube in a bottom of a gasification reactor according to the invention.

The gasification reactor shown in Fig. 1 according to the invention has a vertical shaft 1 with an upper opening 3 , through which, for example by means of a rotary valve 5 pieces, carbonaceous solids such as wood, plastic, rubber, paper and textile waste and the like introduced can be.

The solids form a solid bed 7 in the upper part of the shaft 1 up to a support 9 in the form of a prism, which can be pivoted about a pivot axis 11 , and in the middle of its prismatic roof 13 has a rigid sheet metal plate 15 , which loosens the solid Bed 7 and for closing any gas channels formed in the bed when the prism 9 is pivoted about the pivot axis 11 . The prism 9 forms constrictions 17 , 19 on its two sides to the shaft inner walls 21 , 23 , so that when the prism oscillates, 13 solid particles are transported down through the constrictions 17 , 19 into a chamber 25 in the shaft 1 .

The gasification of the solid bed above the bottlenecks 17 , 19 is promoted by supplying fresh air through nozzles 18 , 20 , and in an amount that corresponds to a substoichiometric proportion of oxygen based on the amount of gas generated in the solid bed. The nozzles 18 , 20 pass through the shaft side walls at different heights in the upper part of the shaft and can surround the shaft circumference in the form of nozzle rings with uniformly spaced nozzles.

In the chamber 25 , the degassing of solid parts which have fallen through the narrow points 17 , 19 is continued. From the chamber 25 , the gas generated is drawn off together with dust or ash parts via a lateral tube 27 and fed to a cyclone, not shown, where dust and ash are separated by centrifugal means, while the gas burns in a separate process to produce Ver Useful heat is supplied.

An ash bed 29 is formed in the lower region of the shaft, into which solids that have not yet been completely gasified also fall. Disierbett In this ash or flui 29 opens laterally, a feed tube 31, through which by means of a screw conveyor 33, first a basic filling with a fine inert material such as sand or ash and the deposited from the mentioned cyclone material during operation, and possibly additional orga nical fine-grained material is conveyed into it.

The proportion of organic material should preferably be overall not more than 3%.

The bottom 35 of the fluidizing bed 29 is penetrated by nozzle tubes 37 , one of which is shown in detail on a larger scale in FIG. 6 in longitudinal section. Referring to FIG. 6, each nozzle tube 37 is formed by a tubular piece which is closed at the top by a cover 39. In the part of the pipe section 37 projecting upward from the ground, nozzle bores 41 are provided which are inclined downwards from the inside out. The nozzle bores 41 are thus directed downward into the fluidizing bed 29 . Due to this construction of the nozzle tube, an outflow of inert material from the fluidizing bed 29 into a gas chamber 43 which is arranged under the bottom 35 and is fastened to the bottom 35 below the shaft 1 is avoided. The gas chamber 43 has a side gas inlet 45 for an oxygen-containing fluidizing gas, which is pressed or sucked into the chamber 43 in the direction of the arrow f. This Fluidi siergas flows through the nozzle tubes 37 and the nozzle bores 41 into the bed 29 and fluidizes the inert material there, so that a fluidized bed is formed from the fluidizing bed.

The differential pressure between the chamber 25 and the gas chamber 43 is measured via local pressure tapping openings 47 in the shaft wall and 49 in the chamber and is entered into a regulator 51 . There is a comparison with a predetermined setpoint for the pressure difference. A rule deviation is corrected by actuating the drive motor for a rotary valve 55 via the output signal line 53 of the controller 51 . The rotary valve 55 sluices depending on the duration of the operation, which is tuned to the desired Druckun difference, a predetermined amount of inert material from the fluidized bed 29 via a discharge pipe 57 , which penetrates the bottom 35 and the chamber 43 vertically.

The temperature in the fluidized bed 29 is detected by means of a temperature sensor 59 and supplied to a controller 61 , which carries out a control comparison with a predetermined temperature setpoint in the order of 850 ° C. and, in the event of a control deviation, outputs a control signal via the control signal line 63 to a control valve 62 . The control valve 62 is in a branch line 60 for oxygen-rich gas, for. B. air, turned on, which opens into the line 46 downstream of a set to a desired flow valve 65 .

The two control loops with the controllers 51 and 61 are only shown in FIG. 1, but can also be provided in the same or modified form in the other design variants. For example, instead of a Regelven valve in line 46 , a control of the oxygen content in a pressure source for oxygen-containing fluidizing gas can also be provided.

The variant according to FIG. 2, in which the same parts have not yet been described, differs essentially in that the base 35 is inclined in a funnel-like manner towards the central discharge pipe 57 . This means that there are 29 different fluidized bed heights in the fluidized bed: The fluidized bed height is larger in the middle than outside. Thus, the entire fluidized bed is uniformly fluidized, these different fluidized bed height is taken into account that the nozzle bores 41 of the lower-lying nozzle tubes 37 a greater in size than the nozzle bores 41 of the higher nozzle tubes b 37 so that through the lower-lying nozzle tubes 37 a larger amounts of gas flow than through the higher nozzle tubes 37 b.

Another difference of the embodiment according to FIG. 2 is that instead of a rotary valve 55, a conveyor screw 56 is provided for laterally discharging the ash to be removed from the fluidized bed 29 via the discharge pipe 57 . The screw 56 can convey into an ash container (not shown), from which the ash is then returned to the fluidized bed 29 via the screw 33 .

In the embodiment of Fig. 3 is different single Lich, that the bottom 35 is funnel-like manner inclined in the direction toward the shaft center to the top. It is thus favored that heavy or large parts, such as metal parts, which cannot be brought into suspension, get into the discharge pipe 57 due to their gravity and due to the movement in the fluidizing bed. The ash is here via a ring channel 58 surrounding the outer edge of the bottom 35 , which wrestles over vertical pipes 59 below the chamber 43 , so that there is the least oxygen-containing fluid gas flowing out.

In the variant according to FIG. 4, the chamber 25 tapers below the prism 9 in the shaft 1 downwards. The left shaft wall 1 a leaves a through to the floor through 67 let free. The gas chamber 43 is divided by a partition 44 into two chamber halves 43 a and 43 b, both of which are provided with their own gas inlets 45 a and 45 b. A fluidized bed forms here to the left and right of the passage 67 leaving wall 1 a of the shaft in partial spaces 29 a, 29 b, the fluidized bed height in the fluidized bed part 29 a in the shaft being considerably higher than the fluidized bed height in a closed chamber part 69 the vertebrae part 29 b. Accordingly, the must be considerably larger than the nozzles 37 d in the Wirbelbetteil 29 a Fluidisiergasmenge introduced as siergasmenge via the nozzles 37 e supplied Fluidi. The nozzles 37 e and 37 d mentioned are to be dimensioned accordingly and the amounts of fluidizing gas supplied via the inlets 45 a and 45 b are metered.

From the closed space 69 above the fluidized bed part 29 b, the gas obtained is returned via a gas line 71 into the upper region of the shaft above the narrow points 17 , 19 to promote degassing and gasification in this shaft part. Alternatively, the gas discharged from the closed space 69 can also be supplied for a different use, for example a special combustion process for obtaining useful heat.

In the variant according to FIG. 5, the fluidizing chamber 75 containing the fluidized bed 29 is completely separated from the chamber 25 by a horizontal wall 73 , so that a fluidizing chamber 75 which is completely closed off from the chamber 25 is formed. The fluidized bed 29 produced in this fluidizing chamber 75 is fed with inert and gasified material as in the embodiment according to FIGS. 1 to 3 via a screw conveyor 33 and an inlet 31 , the screw conveyor 33 also having a vertical pipe section 81 and a discharge screw 77 Drive motor 79 is fed from the chamber 25 with ash and only partially ver gasified solids.

In this case too, as in the embodiment according to FIG. 4, a gas line 71 leads from the fluidizing chamber 75 back into the upper region of the shaft.

Otherwise, the configuration is the same as in the embodiment according to FIG. 1.

Reference list

1 shaft
3 opening
5 rotary valve
7 fill
9 support / prism
11 swivel axis
13 roof / prism
15 sheet metal plate
17 constriction
18 nozzle
19 constriction
20 nozzle
21 shaft inner wall
23 inner wall of the shaft
25 chamber
27 tube
29 ash or fluidizing bed / fluidized bed
29 a fluidized bed part
29 b fluidized bed part
31 feed pipe / inlet
33 screw conveyors
35 floor
37 nozzle pipe / pipe section
37 a nozzle pipes
37 b nozzle pipes
37 d nozzles
37 e nozzles
39 cover
41 nozzle holes
43 gas chamber
43 a chamber half
43 b chamber half
44 partition
45 gas inlet
45 a gas inlet
45 b gas inlet
46 line
47 pressure ports
49 shaft wall
51 controller
53 Output signal line
55 cellular wheel sluice
56 screw conveyor
57 discharge pipe
58 ring channel
59 temperature sensors / pipes
60 branch line
61 controllers
62 control valve
63 Control signal line
65 valve
67 passage
69 chamber part
71 gas pipe
73 wall
75 fluidizing chamber
77 discharge screw
79 drive motor
81 vertical pipe section

Claims (17)

1.Procedure for the gasification of solids, in particular residues, in which the solids are filled into a shaft, gasified at least in part with controlled, substoichiometric supply of fresh air and the solids and gases which have not yet been completely gasified are fed to a chamber via at least one constriction of the shaft, in which the solids are gasified and withdrawn from the gases, forming a bed from which ash is discharged, characterized in that an inert, fluidizable material and a fluidizing and reaction gas in one to produce a fluidized bed in the bed sufficient amount is introduced. 2. The method according to claim 1, characterized records that the fluidized bed trained in the shaft det. 3. The method according to claim 1, characterized records that the fluidized bed below the Shaft or next to it. 4. The method according to any one of the preceding claims, characterized characterized that the fluidized bed height depending on a predetermined pressure difference above is regulated half and below the fluidized bed. 5. The method according to any one of the preceding claims, characterized characterized in that as fluidizing and Reaction gas is a mixture of air or oxygen and Exhaust gas from the combustion process is used. 6. The method according to any one of the preceding claims, characterized characterized that the temperature in the we bed by regulating the amount of fluidizing and Reaction gas or its oxygen content on one predetermined value, preferably around 850 ° C, is held. 7. gasification reactor with a shaft ( 1 ) for filling and at least partially gasifying a solid bed ( 7 ), with at least one support ( 9 ) for the solid bed, which forms at least one constriction ( 17 , 19 ) for the passage of solids and gases, with in the area above the constriction fresh air lines ( 18 , 20 ) for introducing a controlled un terstoichiometric amount of fresh air and with a un below the constriction chamber ( 25 ) which has an outlet ( 27 ) for gases, characterized in that a gas chamber ( 43 ) is arranged separately from the chamber ( 25 ) and has a gas inlet ( 45 ) for a fluidizing and reaction gas; that the gas chamber ( 43 ) is closed at the top by a set of nozzles ( 37 ) through the bottom ( 35 ), that above the bottom ( 35 ) a fluidizing chamber ( 29 ; 75 ) containing inert, fluidizable material is formed and that the fluidizing chamber with an inlet ( 31 ) for introducing the fluidizable material and is connected to the chamber ( 25 ) in a gas-conducting manner. 8. Gasification reactor according to claim 7, characterized in that the fluidizing chamber ( 29 ) in the Bodenbe area of the chamber ( 25 ) is formed. 9. Gasification reactor according to claim 7, characterized in that the fluidizing chamber ( 29 a, 29 b; 75 ) is separated from the chamber ( 25 ) by a wall ( 1 a; 73 ) and via an exhaust pipe ( 71 ) with the shaft ( 1 ) above the constriction ( 17 , 19 ) is connected. 10. Gasification reactor according to claim 9, characterized in that the fluidizing chamber ( 75 ) is below the shaft ( 1 ) and the horizontally extending wall ( 73 ) closes the shaft ( 1 ) downwards. 11. Gasification reactor according to claim 9, characterized in that the fluidizing chamber is divided into two sub-rooms ( 29 a, 29 b), one of which ( 29 a) in the bottom region of the shaft ( 1 ) and the other ( 29 b) next to it is arranged that the wall ( 1 a) forms the lower end of a vertical lateral boundary wall of the shaft ( 1 ) and a side passage ( 67 ) for establishing a connection between the two sub-spaces ( 29 a, 29 b) that the gas chamber ( 43 ) by a partition ( 44 ) is divided into two sub-chambers ( 43 a, 43 b) and that each sub-chamber is provided with its own gas inlet ( 45 a, 45 b) for different exposure to fluidizing and reaction gas. 12. Gasification reactor according to one of claims 7 to 11, characterized in that a Fördervor direction ( 33 ) for feeding fluidizable material into the inlet ( 31 ) of the fluidizing chamber ( 29 ) above the bottom ( 35 ) is provided. 13. Gasification reactor according to one of claims 7 to 12, characterized in that the bottom ( 35 ) and the gas chamber ( 43 ) are penetrated by a discharge pipe ( 57 ) for inert material, with a controllable discharge device ( 55 ) for inert material in the Discharge pipe is arranged. 14. Gasification reactor according to claim 13, characterized in that the bottom ( 35 ) to the discharge pipe ( 57 ) is inclined. 15. Gasification reactor according to claim 14, characterized in that those nozzles ( 37 a) which enforce the deep-lying genes of the bottom ( 35 ), larger flow cross-sections ( 41 ) than the nozzles ( 37 b) at the higher positions of the Floor ( 35 ). 16. Gasification reactor according to one of claims 12 to 15, characterized in that a level control device for controlling the fluidized bed height (h) of the fluidized bed formed on the floor ( 35 ) with pressure sensors ( 47 , 49 ) for detecting the pressure difference between the fluidizing chamber ( 29 ) and the gas chamber ( 43 ) and with a controller ( 51 ) for regulating this pressure difference to a setpoint by controlled removal of fluidizable material by means of the Ausleusvorrich device ( 55 ) is provided. 17. Gasification reactor according to one of claims 7 to 16, characterized in that a Temperaturregelvor direction ( 61 ) for the temperature in the fluidizing chamber ( 29 ) with a temperature sensor ( 59 ) for detecting the temperature and regulating to a temperature setpoint by setting the amount of fluidizing and reaction gas supplied via the gas inlet ( 45 ) or their oxygen content is provided.