DE4339973C1 - Granulated wastes mixed with coal grains and gasified with oxygen and steam - Google Patents

Abstract

In a process to gasify waste residues with the aid of a gas containing O2 the novelty is that the granulated residues are mixed with coal (2) granules of the same size and gasified with the gas containing O2 and water steam (3) at temperatures between 750 and 1000 degrees C in the fluid bed of an HTW-gasifier (1). The result is a dust-laden raw gas (14) and a base product (11), which are gasified together with a further fuel (23) at temperatures above 1500 degrees C in a downstream dust gasifier (22) with a gasification agent containing O2 and steam (24). The non-gasified residues and pollutants are bound in slag (28) which is located at the output point of a water washer (27) under the dust gasifier (22).

Description

The invention relates to a method for gasifying waste materials with the help of an O₂-containing gas. A similar process is Already known from DE 36 16 785 A1.

In the known "process for working up carbon-containing Waste and biomass "are the waste materials with hydrogen and / or Gases containing hydrogen are implemented in the fluidized bed. Here is a hydrogenation reaction with feed gases, in which the Hydrogen content is more than 25 vol .-%. The implementation takes place in Presence of additional solids such as coal or coal components of life. The known method is very suitable for the joint hydrating treatment of waste or waste mixtures and coal or coal components. As fluidized bed reactors Such devices can also be used to implement the substances the kind used in coal gasification. It is also in known in this context, the substances to be implemented, including the coal to be crushed in the fluidized bed reactor before implementation. The known method serves the goal, despite the use of completely inconsistent waste materials from it valuable hydrocarbon oils to win in high yield.

The well-known implementation of waste materials takes place at between printing 1 and 150 bar and is preferably between relatively high pressures between 25 and 60 bar.  

Notwithstanding a possible feasibility of the known method has not yet found this in practice. Next the use of relatively high pressures is essential Disadvantage of the known method in that it is the fact does not do justice to the waste that is to be converted as a rule also contain chlorine. Chlorine is used in industrial conversion drive viewed as a very unpleasant accompanying substance because of it is very aggressive and the facilities required for implementation attacks. In addition, the conversion of waste materials with the help of Gases containing hydrogen as part of a hydrating treatment very expensive.

DE 30 11 157 A1, which is also known, relates to a method for the gasification of waste using oxygen in a gasification reactor at any pressure between 0 and 200 bar and temperature between 1400 and 1500 ° C (see page 6, paragraph 2) by using the pre-sorted garbage before gasification to a particle size smaller 2 mm crushed and with a whole substance, especially coal, mixed, which was crushed to the same grain size.

The focus of the known method is obviously on Gasification of garbage and less on a combined gasification of Residual materials and coal, as is the case with the subject of the application is. But apart from that is the procedural preparation the substances to be gasified are comparable in both cases. With the subject of registration as with the prior art, the rest shredded materials and coal to a given grain size mixed and placed in a gasification reactor where they be converted with the help of an oxygen-containing gas.  

With such a conversion, and that is the relevant Ver known to the gassing specialist, residues are created that still contain carbon contain and in which so-called pollutants such. B. Heavy metals, are included. The carbon content of this residual coke gives it a calorific value and makes it for it suitable to be used still energetically. The contained Pollutants, on the other hand, restrict further thermal use a, if it does not succeed, pollutants and carbon content of the Separate residual coke from each other.

In any case, a possible deposit of such residual coke would be worst solution, because apart from too large a volume on residual coke that would have to be placed in the landfill is not ensures that the pollutants from the deposited coke also cannot be drained.

DE 31 30 031 A1 relates to a process for gasifying coal oxygen-enriched air and water vapor. The gasification takes place in a first gasification stage, preferably in one Winkler generator, at temperatures below the slag softening point in the range of about 800-1200 ° C and pressures in Range from 1-100 bar to form a carbon-containing fine well-containing gas. The carbonaceous fine material continues gasified in a vortex gasifier at temperatures above of the slag pour point, preferably at temperatures between 1450 and 1850 ° C. This causes all of the carbon gasification degree of both levels increased to over 90%.  

The known method therefore aims to improve the coals material utilization in coal gasification in the fluidized bed (cf. Page 5, paragraph 2). At the same time, they are said to be environmentally harmful Accompanying substances of coal, such as sulfur compounds, in a harmless landfill-compatible form (see page 5, paragraph 2). The In the applicant's view, known teaching alone is sufficient not out to solve those problems if aggressive components - like Chlorine - and environmentally harmful substances - such as heavy metals - with in Games are, whose behavior can sometimes be completely unpredictable can.

Also in a possible review of DE 30 11 157 A1 and DE 31 30 031 A1, the inventors were unable to solve their problem Find. Because the first does not give the gasification specialist an answer on what to do with the polluted coke and the the second only speaks of environmentally harmful sulfur compounds, without the expert a solution to his problems with chlorine and Offer heavy metals that are unsan in converting garbage make it noticeable.

The problem arises from the disadvantages of the known methods for the present invention, a method for converting Ab propose waste materials that are economical and at their disposal End the pollutants contained in the waste materials in a sol Chen condition can be transferred that they are neither the facilities attack for conversion or harm the environment.

The solution to this problem was in the features of the main claim found.  

The bottom product consists of residual coke, which contains the pollutants converted waste is enriched. This residual coke is kör nig and is therefore first cooled and then finely ground before it is fed to a further gasification in a dust gasifier. The dust gasifier is, for example, one in the Well known Shell or Krupp / Koppers carburettors. Dust gasification also takes place with the help of an oxygen content against gas and steam as a gasifying agent. In addition, if necessary an additional fuel, for example again in the form of dust ground coal abandoned. To close the process cycle it is envisaged the dust that is extracted from the HTW gasification was separated with the finely ground soil product to mix and enter together in the dust gasifier. Of the Dust carburetor is also suitable for this, at the same time as the dust raw materials and other waste materials and other residues to gasify. For example, they flow into the dust gasifier sig and / or pasty waste materials, such as PCB-containing oils or the at of the residues of paint or varnish, in the Abandoned dust carburetor. There is a substoichiometric one Combustion at temperatures above usually 1500 ° C, whereby a complete C conversion is achieved.

At the location of the downstream dust gasification, a thermal treatment of the dusty products on about that same temperature level in a melting chamber combustion respectively.

During the implementation in the dust gasifier, the non-gasifiable remnants fall substances as liquid slag. This liquid slag is next to the raw gas produced in the dust gasifier is fed to a water wash. Out the raw gas can be withdrawn from the water wash and the ver Gas residues, especially the heavy metals, remain in the  slag-forming ashes of the additional fuels cannot be eluted bound. The integration takes place mainly in the form of glass. In transferred this final state, the pollutants can safely depo be kidneyed.

The raw gases from HTW gasification and dust gasification are combined led and a common raw gas aftertreatment, esp especially a water wash and a sour gas wash in the water the chlorine components are washed out. That too with the Water washes of the raw gas obtained in the HTW gasifier as well as that in the Dust gasifier obtained from raw gas waste water can accumulate managed and reprocessed.

Instead of the dust gasifier, one can advantageously also Melting chamber firing with liquid slag discharge, for example a Melting chamber cyclone can be used. Here, soil product, Dust and other residues with excess air at temperatures of usually treated above 1500 ° C, which also makes a full constant C turnover is achieved. The heavy metals brought in are embedded in the slag and cannot be eluted.

The resulting flue gas is cleaned using known washing methods freed world-damaging trace substances and released into the atmosphere.

Further advantages of the method according to the invention result from the individual subclaims. In the subclaims 11 to 14 Protection for the characteristics of a facility for carrying out the inventions claimed method. The invention is as follows described in more detail using an exemplary embodiment.

The only figure shows in a schematic and highly simplified A flow diagram of a device for implementation of the method according to the invention.

A high-temperature Winkler carburetor, called HTW carburetor 1 , is laid out for example for a throughput of 26 t / h of dry brown coal. This throughput corresponds to a heating value current of 560,000 MJ / h. For this purpose, pre-dried dry lignite, crushed to a grain size of up to 6 mm, is provided. The coal from waste materials are added, which are reduced to approximately the same grain size and are mixed together before entering 2 in the HTW carburetor 1 . The waste materials, from dried sewage sludge to plastics, can be all common waste materials that contain carbon. An enumeration of the individual possible waste materials is superfluous, since one can assume that they are known to the person skilled in the art, and their enumeration should make the present description extraordinarily extensive, without this scope contributing significantly to the clarity of the present description. As a result, in the following description, the substances sewage sludge and plastics are named for all relevant solid waste materials.

Since plastics are considerably more energy-rich than coal, the addition of coal is based on the respective calorific value of the waste materials to be forgotten. In the gasification of plastics, an entry 2 of 10 t of plastics and 10 t of coal is given up. He put 10 tons of plastic in terms of energy content 16 tons of coal.

When sewage sludge is converted, 10 t of coal are converted into 15 t of sewage mud replaced. In both cases it is assumed that it is the coal by pre-dried and pre-broken to 6 mm grain sizes Lignite is involved.

This entry 2 is implemented with the help of a mixture 3 , which consists of an O₂-containing gas and steam, in the HTW gasifier at temperatures between 750 and 1000 ° C. The resulting raw gas 4 is dust-laden and is drawn off at the top of the HTW gasifier 1 . It is customary to quench the HTW raw gas 4 by withdrawing water 5 before it is drawn off from the HTW gasifier 1 .

The HTW raw gas 4 is first passed through a separator 6 , where the solid, incompletely converted components are separated and returned to the lower part 8 of the HTW gasifier 1 via a line 7 . A line for the supply of a fluidizing gas 9 also opens into the lower part 8 . It is a medium which has 2 less oxygen in relation to the other gasification agents. At the lower part 8 , the unreacted components of the coal and waste 2 are withdrawn in the form of residual coke, which is enriched with chlorine and heavy metals. The residual coke is granular and is first conveyed through a cooling system 10 , at the outlet 11 of which it is present at a temperature of approximately 350 ° C. In this state, the cooled residual coke 11 is fed to a grinding 12 , at the outlet 13 of which it is in dust form.

From the separator 6 , the raw gas 14 generated in the HTW carburetor 1 and loaded with dust emerges at temperatures between 800 and 950 ° C. The reason for the temperature decrease of approximately 50 ° C. between the temperature in the HTW gasifier 1 and the raw gas 14 lies in the water quench 5 . The still hot raw gas 14 is first subjected to cooling 15 . At its outlet 16 it is at temperatures between 200 and 350 ° C. The cooling 15 is a cooling with indirect heat exchange. The cooled raw gas 16 is then subjected to a dry dedusting 17 . A dust-free raw gas 18 and the dust 19 that was discharged from the separator 6 with the raw gas 14 are produced . The dust 19 is cooled in the cooling 20 and gene together with the finely ground residual coke 13 in the form of powdered residues 21 eingetra in a dust gasifier 22. In the dust carburetor 22 is a shell carburetor or a Krupp-Koppers-gasifier. The Staubverga water 22 is also given an additional fuel 23 to be gasified while supplying a gasifying agent 24 . In the Verga smittel 24 is also a mixture of an O₂-containing gas and water vapor. At the same time, further waste materials and other residues 25 can also be gasified. These are preferably liquid or pasty wastes, such as those obtained as PCB-containing oils or paint residues or paint sludges in industry.

In the dust gasifier 22 there is a complete C conversion of the input materials 21 , 23 and 25 at temperatures above 1500 ° C. With this substoichiometric dust combustion, raw gas and slag 26 accumulate together at temperatures of more than 1500 ° C.

Both are fed to a water wash 27 , which is operated with the aid of wash water 31 . When it is removed from the dust gasifier 22 , the slag 26 consisting of the non-gasifiable constituents is thus in liquid form. In the treatment in water washing he stares at glass-shaped slag 28 , in which the waste substances 2 and 25 are incorporated into the gasification process. At the same time, a raw gas 29 is obtained from the water wash 27 , which is added to the raw gas 18 . This has to go through a water wash 30 where it is treated with wash water 31 . After the water wash 30 , the raw gas generated in the HTW gasifier 1 is in a mold 32 in order to be fed to a common raw gas aftertreatment (not shown) sour gas wash. In the course of this raw gas aftertreatment, trace substances contained in the raw gases 29 and 32 may still be washed out.

Finally, wastewater 33 and 34 accumulates at the water washes 27 and 30 , which is fed together to a wastewater treatment 35 .

The particular advantage of the present invention is based on the knowledge that the HTW carburetor 1 is a universal residue gasification machine. In cooperation with the dust gasifier 22 , the gas obtained there can be taken into the existing cleaning systems for the raw gas 14 and used in this way as part of the raw gas 32 to be further processed for synthesis gas.

Reference list

1 HTW carburetor
2 Coal / waste entry
3 gasifying agents
4 HTW raw gas
5 water quench
6 separators
7 return line
8 lower part of HTW carburettor
9 fluidizing gas
10 cooling
11 cooled residual coke
12 grinding
13 dust-like residual coke
14 dust-laden raw gas
15 indirect cooling
16 cooled raw gas
17 Dry dedusting
18 dust-free raw gas
19 dust
20 cooling
21 dusty residues
22 dust carburetor
23 Additional fuel
24 gasifying agents
25 liquid waste
26 raw gas and slag
27 water wash
28 glass slag
29 raw gas
30 water wash
31 wash water
32 Raw gas for gas aftertreatment
33 waste water
34 waste water
35 Waste water treatment

Claims (16)

1. Process for the gasification of waste materials with the help of an O₂-containing gas by

• - Solid waste and coal crushed to approximately the same grain sizes, mixed together and gasified with O₂-containing gas and water vapor at temperatures between 750 and 1000 ° C in the fluidized bed of a high-temperature Winkler gasifier, called HTW gasifier , in which
• - a dust-laden raw gas and
• - a soil product

in the form of residual coke enriched with pollutants, of which one

• - cleans the raw gas and uses it,

characterized in that one

• - The bottom product together with the dust separated from the raw gas at temperatures above 1500 ° C undergoes a thermal aftertreatment for converting the carbon with an O₂-containing gasification medium by combustion or gasification and thereby the non-gasified residues in an environmentally harmless state transferred.

2. The method according to claim 1, characterized in that the bottom product cools and grinds fine and in a dust gasifier, for example from Type Shell or Krupp-Koppers carburettors gasified. 3. Process according to claims 1 and 2, characterized in that the HTW carburetors generated raw gas cools and dedusted dry and the won dust, if necessary after further cooling, with the finely ground Bo the product is mixed and gasified. 4. Process according to claims 1 to 3, characterized in that one Mixture of ground soil product and dust together with additional fuel fen and other, especially liquid or pasty waste materials in the Dust gasifier gasified.   5. The method according to any one of claims 1 to 4, characterized in that Use water vapor as a gasifying agent in the dust gasifier det. 6. The method according to any one of claims 1 to 5, characterized in that withdraws a raw gas and slag from the dust gasifier and together one Undergoes water washing. 7. The method according to claim 1, characterized in that one in HTW Ver gas produced raw gas after dry dedusting under a water wash pulls. 8. The method according to claims 6 and 7, characterized in that one Raw gas generated in the dust gasifier after washing it in the HTW gasifier produced raw gas before it was washed. 9. The method according to claim 6, characterized in that the deducted and solidified slag deposited. 10. The method according to claim 4, characterized in that PCB-containing oils, Colorant waste as well as paint and paint sludge as liquid or pasty Waste materials in the dust gasifier are also gasified. 11. Device for the gasification of liquid, pasty and solid waste materials together with coal according to one of the preceding claims 1 to 10, characterized by

• - A HTW carburetor ( 1 ) with a
• - Separators ( 6 ) for dust-laden raw gas ( 14 ), the devices for cooling ( 15 ), dedusting ( 17 ) and water washing ( 30 ) of the raw gas ( 18 ) are connected downstream and with
• - Means for cooling ( 10 ) and grinding ( 12 ) for the bottom product ( 11 ), which
• - A dust carburetor ( 22 ) for gasification at high temperatures is switched to which one
• - Water wash ( 27 ) for the slag ( 28 ) and raw gas ( 29 ) drawn off from the dust gasifier ( 22 ).

12. The device according to claim 11, characterized in that the Trockenent dust ( 17 ) for the raw gas ( 16 ) obtained in the HTW gasifier ( 1 ) is preceded by cooling ( 15 ). 13. The device according to claim 12, characterized in that the Trockenent dust collector ( 17 ) for the raw gas ( 16 ) obtained in the HTW gasifier ( 1 ) is followed by a dust cooler ( 20 ). 14. Device according to claim 12, characterized in that the Trockenent dust collector ( 17 ) for the crude gas ( 18 ) obtained in the HTW carburetor ( 1 ) is followed by a water wash ( 30 ).