DE3101259A1 - METHOD FOR PRODUCING A COMBUSTIBLE PURE GAS FROM COAL - Google Patents

Description

PATIINTAN WALTE

DR. DIETER V. BEZOLD DIPL. ING. PETER SCHÜTZ DIPL. ING. WOLFGANG HEUSLER

MARIA-THERESIA-STRASSE 22

D-8OOO MUNICH

US Ser. No. 115,116 Filed January 24, 19 80

TELEPHONE 089/47 69 4763

FROM SEPT. 1980: -4 706006 TELEX 522638 TELEGRAM SOMBEZ

10 931

Dr.v.B./V/m case 36-237

Tosco Corporation 10 100 Santa Monica Blvd. Los Angeles, Calif. 900 V.St.A.

Process for the production of a combustible pure gas from coal

For some time there has been considerable interest in the use of coal to produce combustible gases, which in turn can be used to generate electricity. A method that can be used to transfer Coal into combustible gases has been proposed includes coal gasification with steam and oxygen and combustion of the obtained gas in a gas combustion turbine

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for generating electricity. That after this type of coal gasification produced gas must be scrubbed to remove impurities, and the method has many disadvantages. E.g. the gas contains different amounts of volatile combustible material (VCM or volatile combustible matter), and part of this VCM is coal tar which is sticky and difficult to handle. The tar associated with certain dust-like material that is produced during coal gasification is in the gasification process produced gas present. These two materials clog and contaminate the system parts located in the downstream, which makes it extremely difficult to recover the heat from the gas made from coal. In addition, when the gasification stage is combined with cycle power generation, the operation of the gasifier and one combined cycle-powered factory are interdependent, so starting up and controlling one integrated factory is impossible without external fuel and auxiliary equipment, which increases costs quite significantly.

Another known method of treating coal is found in an article entitled "Production of Low Btu Gas Involving Coal Pyrolysis and Gasification" by Wen et al, Chemical Engineering Department of West Virginia University, Morgantown, West Virginia 26506, pp. 36-12 54. This article suggests pyrolyzing coal in a fluidized bed at about 760 ^° C (1400 ^° F). The coal residue or coke-like substance produced during pyrolysis, hereinafter referred to as "charcoal", is separated from the outflowing gas, and the charcoal is then reacted with air and steam, with fluidizing gases for the coal pyrolyser being produced. It is emphasized in the article, however, that in order to gasify the charcoal, raw coal must be added to the charcoal feed in order to maintain the correct temperature in the gasifier.

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temperature and in addition to produce a sufficient amount of gas to fluidize the coal. Because the way in which the coal is pyrolyzed in the fluidized bed, and because raw coal becomes the pyrolyzed artificial If coal had to be added, the method proposed by Wen et al would address most of the disadvantages described above of the known processes.

Another prior art method is disclosed in U.S. Patent 1,758,630 (Trent), suggested in US Pat will pyrolyze coal in a fluidized bed, remove any volatile combustible material from the coal, and after that contacting the resulting charcoal with air and steam to produce a synthesis gas. This process is also unproductive, probably in part because of the manner in which the charcoal is produced.

In this respect, none of the known processes relates to the production of a partially freed from volatile constituents charcoal product by pyrolysis of the coal in such a way that the coal is ideally suited for gasification is. The gasification of such artificial coal produces a gas that is tar-free and ideal for combustion is suitable, especially if it is with the gaseous vapors (e.g. after the condensable products are removed are) that have been produced in the pyrolysis stage is mixed.

Therefore, it is the first object of the present invention to provide a simple and improved method of making a combustible gas from a special type of a partially volatilized charcoal with steam and an oxygen-containing gas • and to provide.

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Another object of the present invention is to provide a method for producing a combustible gas for To provide use in a combustion gas turbine made of charcoal, the charcoal Contains some volatile combustible material, but no tar-forming constituents.

Another and further object of the present invention is to provide a method of making a combustible Partially de-volatilized charcoal gas for use in combustion gas turbines to disclose and provide wherein the combustible gas is substantially free of heavy coal tar and dust is to prevent the pollution of the heat exchange and process equipment to prevent.

Yet another and further object of the present invention is to provide a method of making a combustible Produce gas from charcoal with a medium BTU value by mixing from coal pyrolysis obtained gases with gases obtained by gasification of a partially freed from volatile constituents artificial Coal with steam and an oxygen-containing gas have been obtained, the gas mixture being free of heavy coal tar is.

Further objects of the present invention will be disclosed from the following detailed description in which all Quantities are given in parts by weight and percent by weight.

The drawing is a schematic representation of a flow diagram and shows certain preferred embodiments of the overall method of the invention.

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Preferred embodiments are described below: '

In the invention, coal is pyrolyzed in a particular way to remove some of its volatiles Manufacture exempted charcoal, which is gasified with steam and an oxygen-containing gas for manufacture a tar-free gas is ideal. The artificial coal, which has been partially freed from volatile components is essentially non-puffy, has a relatively high bulk density, and is high for gasification with steam responsive. In addition to the valuable, partially Volatile charcoal produced in the pyrolysis stage also becomes volatile Vapors and condensable gases are produced. The volatile vapors can be used because of their calorific value, and the condensable gases, when condensed, are valuable hydrocarbon liquids that reside in the petrochemical industry or the petroleum industry or which can be burned because of their calorific value can be.

The pyrolysis step is carried out in a pyrolysis zone in a particularly critical manner which involves contacting the carbon particles with heat-laden solids in a non-oxidizing atmosphere, preferably in the absence of other extraneous gases. The heat-laden, heat-carrying solids come into contact with the dried carbon particles in such a way that the heat-carrying solids heat the carbon particles to the desired pyrolysis temperature, for example from 370 ° C. (70O ⁰ F)

82O ° C (1500 ° F), preferably from 43O ° C (800 ° F) to 65O ° C, most preferably _n η no (120CTF), / 430 C (800 F) to 540 C (1000 F). The carbon particles are absorbed by the heat-carrying solids for a sufficient time and at a sufficient temperature.

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door heated to remove all of the tar-forming VCM from the coal particles to remove. In the pyrolysis zone, volatile vapors, condensable gases (hydrocarbons, which are liquids at room temperature) and artificial charcoal particles partially freed from volatile components, the VCM remaining in the artificial charcoal particles, which have been partially freed from liquid components contains no condensable tar material. It has been found that such, partly of volatile constituents freed charcoal particles are excellently suited for gasification with steam because the charcoal particles contain some and preferably all of the non-taring VCM, but no taring VCM. moreover have the artificial charcoal particles, some of which have been freed from volatile components, have a relatively high bulk density (e.g. over 320 kg / m = 20 pounds per cubic foot) and preferably over 400 kg / m = 2 5 pounds per cubic foot), which they also makes very valuable as a gassing feedstock. In addition, some of the volatile components have been removed charcoal particles made in accordance with the present invention are highly reactive, i.e. such charcoal particles require less steam to be gasified.

The combustible gas, the artificial charcoal particles that have been partially freed from volatile constituents by gasification has been manufactured has many uses. E.g. the combustible gas produced by gasification of partially Volatile coal has been produced using steam and air (as opposed to pure oxygen) is to be mixed with the volatile vapors that have been produced in the pyrolysis zone and then yield a gas with a medium BTU value (i.e. a gas with a calorific value in the range of 200 to 600 BTU or 210 to

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630 KJ per standard cubic foot), which in common heating systems and furnaces can be burned without modifying the burner or reducing equipment capacity. It is well known to those skilled in the art that it is impossible to produce a mid-BTU gas by oxidizing it of the carbon in coal using air as an oxidizer to raise the temperature. but because the volatile vapors generated in the pyrolysis stage are not diluted with foreign gases such as nitrogen the method provides a mid-BTU gas in a very simple and inexpensive manner.

In addition to the use of the combustible gas produced by the gasification of some of the volatile components

artificial
exempted / coal is produced, to produce a gas with a medium BTÜ value, the combustible gas can also be used to generate electricity in a combustion turbine, and just as well can be used to compress air and produce steam, used in the gasification of the artificial coal, which has been partially freed from volatiles, without contaminating the downstream equipment and the like with pollutants such as tar, which - as already mentioned - would complicate the recovery of thermal energy from the gasification product. In addition, such use of the gasification product in the manner described above eliminates the need for external fuel and certain ancillary equipment that would make the process comparatively expensive and perhaps not economically feasible.

In general, it is preferred that the raw coal be ground into particles, e.g., one, prior to pyrolysis of the coal Size from 1.27 cm to 0.3 cm (-1/2 inch to -1/8 inch). After the coal has been ground, it is also preferred

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I SUBMITTED

when the moisture is removed from the coal in a preheating stage by, for example, heating the coal particles a temperature of 93 ° C (200 ° F) to 32O ° C (600 ° F) and for a long enough time to remove all of the moisture. If the coal is a baking or Easterntype Is coal, it is generally preferred that the coal be either before, after, or during the drying step is pretreated to de-bake the charcoal by contacting the coal with an oxidizing gas containing, for example, 1 to 20% by volume of oxygen, as described in U.S. Patent 3,184,293 (Work). In addition to de-baking the charcoal, such a step removes all of the moisture from the Remove coal. After the drying stage and / or the pretreatment stage, most coals will be around 20% by weight contain up to 50% by weight VCM and from 75 to 50% solid carbon.

In the pyrolysis stage of this invention, the VCM containing the tar is reduced and, in general, the amount of VCM after the pyrolysis stage contained in the coal will be between 10 and 20% by weight excluding moisture. The specific temperature and duration of the pyrolysis stage are not particularly critical, but in general the pyrolysis can be anywhere from 370 ° C (700 ° F) to 82O ° C (1500 ° F) with the preferred temperature range of 430 ° C (800 ° F) 65O ° C (1200 ° F) and the most preferred temperature range of 43o ° C (800 ⁰ F) to 54O ° C (1OOO ° F) are performed. The length of time necessary to carry out the pyrolysis step will also vary widely depending on the temperature and the amount of VCM in the raw coal. For example, if a temperature of 510 ° C (950 ° F) is used and the coal contains about 40 to 45 wt% VCM, a five minute residence time is sufficient to produce a partially de-volatilized charcoal in which the VCM, which is in the partial

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contains artificial charcoal freed of volatile components, no longer contains tar.

The pyrolysis step of the invention is also carried out in a non-oxidizing one Atmosphere carried out and preferably in the absence of foreign gases, so that the vapors that are produced during the pyrolysis stage, not dilute v / ground and the volatile vapors after the condensable Gases removed will have a relatively high BTÜ content per standard cubic foot, e.g. 840 KJ (800 BTU) per standard cubic foot after the condensable Gases have been removed.

The dried carbon particles are pyrolyzed in the non-oxidizing atmosphere by contacting them of the dried coal particles with heat-energy-carrying solids, which are opposite to the coal, which is partly from volatiles are freed from charcoal and from the vapors produced during the pyrolysis stage should be inert. The special type of heat-carrying solid that is used to heat the carbon particles is used can vary widely and can have any desired shape. E.g. the heat-carrying solid body made of metal or ceramic, and can be spherical in shape with a diameter of about 0.64 to 1.27 cm (1/4 inch to 1/2 inch). In the preferred exemplary embodiment, those are heat-carrying Solid aluminum balls approximately 1/2 inch in diameter. In addition, the heat-bearing For easier separation, solids have a size which is the size of the partially volatile constituents exempted charcoal particles is different. In general, it is preferred if the heat-bearing Solid bodies have a diameter that is larger than the diameter of the partially volatile

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artificial charcoal particles freed from components.

In order to transfer the heat energy from the heat-carrying solids to the coal particles, the heat-carrying Solid bodies touch the carbon particles in order to transfer their thermal energy to them. It is preferred if the pyrolysis stage is carried out in a rotating retort. The rotation speed of the retort is sufficient that Mix heat-carrying solids with the coal particles to ensure good heat transfer between the coal particles and to reach the heat-carrying solids. The specific speed of rotation of the retort can vary widely Limits vary and depend on the diameter of the retort. After the pyrolysis is completed, the heat-bearing Solids and the artificial charcoal particles partially freed from volatile constituents are separated, as is the volatile vapors and condensable gases produced during the pyrolysis stage.

The artificial coal, which has been partially freed from volatile components, is then transferred to a gasification zone, where the artificial coal is gasified with steam. The conditions under which the gasification stage is carried out, are not critical and are generally known to those skilled in the art. The temperature in the gasification zone becomes sufficient its to react the steam with the carbon in the partially freed from volatiles artificial Coal, to form a combustible gas that consists primarily of carbon monoxide and hydrogen. The temperature can vary widely and will range from 540 ° C (1000 ° F) to 137O ° C (2500 ° F); the specific The temperature used will depend primarily on whether a gasification catalyst is added to the gasification zone.

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If a gasification catalyst is used, the temperature will be between 54O ° C (1000 ° F) and 815 ° C (150O ⁰ F) or 870 C (1600 ° F), whereas the temperature - if the reaction is carried out in the absence of a gasification catalyst (e.g. as thermal response) - will be higher than 87O ° C (1600 ° F), e.g. from 87O ° C (1600 ° F) to 1090 ° C (2000 ° F) or even higher (e.g. 1370 ° C = 25OO ° F).

As is the case with the temperature of the gasification reaction, the pressure used is to steam the carbon gasification, not critical either, and can vary widely from ambient pressure to 140 bar (2000 pounds per square inch gauge, psig), with no theoretical upper limit for the pressure.

As mentioned above, the gasification reaction can be carried out with or without a catalyst, and the temperature is - when a catalyst used v / ith - vary from 54O ° C (1000 ⁰ F) to 815 ° C (1500 ° F) or 87O ° C (1600 ⁰ F). The gasification catalysts are generally well known and detailed examples of them are not given. However, alkali salts such as sodium, potassium and lithium salts are generally used and include the hydroxide salts, the carbonate salts, the oxide salts, the sulfate salts and the sulfide salts.

The concentration of the catalyst in the gasification zone can also vary within wide limits and is generally from 1% to 50% by weight based on the weight of total solids in the gasification zone. the preferred catalyst concentration ranges from 4 or 5% by weight to 20 or 30% by weight.

The amount of steam that is used to gasify the artificial coal, which has been partially freed from volatile components

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should be sufficient to gasify all the solid carbon contained in the charcoal. In general, the amount of steam will be between 0.1 to 1 part by weight of steam per hour per part by weight of Carbon in the gasification zone and the most preferred range is between 0.2 and 0.6 parts by weight.

The temperature in the gasification zone is determined by introducing an oxygen-containing gas, such as air, into the zone maintained, with some of the carbon that is in which contains charcoal partially devolatilized, is oxidized; such an oxidation reaction is exothermic, and the amount of oxygen introduced must be sufficient to maintain the temperature to keep it at the desired level.

Referring to the drawing, in a preferred embodiment, carbon particles are added to the prior to pyrolysis the upper part of the drying zone 10 and a hot gas is introduced at the lower part of the drying zone 10, the drying temperature in zone 10 being about 120 ° C (250 F). After the drying stage and if any Wyodak coal is used contains the coal composition about 7.6 wt%, ash, 43.9 wt% volatile matter, and 48.5 wt% carbon.

It is emphasized that it - if an Eastern coal is used - then sometimes a pre-treatment stage is necessary either before or after removing the moisture from the coal. This pre-treatment stage serves to de-bake the charcoal and is carried out - as is generally known to the person skilled in the art Bringing the carbon into contact with an oxidizing gas.

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I FOLLOWED

After the drying stage, the dried charcoal is through a preheating zone 12 where the coal is heated to slightly below the pyrolysis temperature.

In the preferred embodiment, the preheater temperature is about 230 ⁰ C (45O ° F), and the oxidizing gas that is used for preheating of the coal particles, preferably contains a gas comprising about 10 vol .-% oxygen. The coal particles leaving the preheating zone 12 have approximately the same composition as the dried coal particles entering the preheating zone 12.

After the carbon particles reach a temperature of 230 ° C (450 ° F) they are transferred to a retort 20 where the pyrolysis step is carried out in the absence of oxygen and other non-foreign gases. In the retort 20, the carbon particles are heated to a temperature of 370 ° C (700 ° F) to 820 ° C (1500 ° F), in the preferred embodiment, 430 ° C (800 ° F) to 54O ° C (100 ° F) ), heated. Heat-carrying solids are used to heat the carbon particles in the retort 20. The heat-carrying or heat-charged solids are preferably ceramic balls which are heated to a suitable temperature in the solid-state heater 14, the ceramic balls ^{reaching a temperature of around 650 to 700 °} C. (1200 to 1300 ^° F) depending on the temperature at which one wishes to carry out the pyrolysis stage. The weight ratio of the heat-carrying solids to the coal is approximately 2.8: 1.

The heat-carrying solids and carbon particles are both introduced into the retort 20 at a relatively slower speed Speed, e.g. three revolutions per minute, to your

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Axis rotates to mix the solids with the coal. After completion of the pyrolysis to the desired point, the volatile vapors and condensable gases are released heat-carrying solids and the charcoal are separated. The separated solids or solids are returned to the solid-state heater 14 via a device 24, and the charcoal particles partially devolatilized become the gasifier 30 promoted. The volatile vapors and condensable gases are transported to the oil and gas recovery zone 22, where the gas with the higher BTU value is separated from the lower-boiling oils and sulfur is removed if necessary will.

The following Table 1 shows the composition of the partially volatilized artificial Charcoal obtained in three different experiments, given the temperature of the retort while the tests are in the top column of Table 1.

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TABEL Composition of the charcoal

Attempt no.

Retort temperature 4 30 ° C 48O ° C 52O ° C

(800 ° F) (900 ° F) (97O ° F)

in% by weight of the charcoal

Moisture ash

volatile combustible material solid carbon

Total 100.0 100.0 100.0

Last (wt%)

0.0 0.0 0 , 0 12.4 10.0 9 ,8th 25.3 19.7 15th , 9 62.3 70.3 74 , 3

68.0 74.7 77.5 3.4 3.0 2.9 13.3 11.8 8.3 1.0 1.2 1.3 0.5 0.2 0.3 12.4 10.0 9.8

Carbon hydrogen oxygen nitrogen sulfur ash

Other dates

Equilibrium Moisture (wt%) 10.0 10.8 9.9 Hnrdgrove Gridability 78.2 49.1 45.6

Calorific values

Gross, KJ / kg 27 531 29 240 30 178 (Gross, Btu / lb) (11 826) (12 560) (12 963)

Net, KJ / kg 26 810 28 588 29 550 (Net.Btu / lb) (11 516) (12 280) (12 693)

Bulk density (1/4 "χ., 0)

packed, kg / m 798 752 736

(Packed, lb / ft) (51.2) (48.8) (47.8)

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In experiment 1 in Table 1, a Wyodak coal was used, one of which had a different composition from the Wyodak charcoal used in experiments and 2.

Tables 2 and 3 show the composition of the oil and the gases in the pyrolysis stage of experiments 1 to 3.

TABLE 2 Oil properties

Retort temperature

Oil properties
Attempt no.

Last (% by weight)

Carbon hydrogen oxygen nitrogen Sulfur chlorine

ash

99.91 100.3 99.9

81.4 80.7 80.9 9.3 9.1 8.7 8.3 9.4 9.3 0.48 0.7 0.7 0.43 0.2 0.2 0.0 0.0 0.0 0.0 0.2 0.1

Calorific values

Gross, KJ / kg 38 622 37 753 37 164

(Gross, Btu / lb) (16 590) (16 217) (15 964)

Net, KJ / kg 36 643 35 786 35 295

(Net, Btu / lb) (15 740) (15 372) (15 160)

API weight (API = American Petroleum Institute)

primary oil 7.9 4.5 1.9

calculated with C ^ 13.2 12.1 6.2

and heavier components of the gas

added

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Pour point C 32 38 35

(° F) (90) (100) (95)

Conradson carbon (wt%) 7.6 9.9 11.4

Distillation (vol .-%)

2.5 10 20 30 40 50

Viscosity (SUS)

82 ° C (180 ° F) 99 ° C (210 ° F)

212 ° C 216 ° C 199 ° C (413 ° F) (42O ° F) (39O ° F) 254 246 207 (490) (475) (405) 301 288 235 (575) (550) (455) 340 329 285 (645) (625) (545) 377 371 338 (710) (700) (640) 407 413 385 (765) (775) (725) 122 123 128 63 66 69

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TABLE of gas analyzes

Retort temperature

Experiment no. 1 2 3

Ingredient (mol%)

co co.

^C 1

^C 2

C ₂ _ (ethylene)

^C 3

C ₃ _ (propylene)

iC,

! .uruhachiut ti irlu. ¹ :? V.olekularyewiclit

Carbon (wt. S)

0.8 1.0 7.8 18.0 17.3 18.4 51.1 42.3 36.4 1.7 1.3 0.3 16.9 22.0 24.9 3.6 4.7 4.4 1.9 1.9 2.4 1.3 2.2 1.2 1.6 3.7 1.6 0.1 0.1 0.0 0.3 2.0 1.1 1.0 1.8 0.7 0.7 0, 6 0.4 0.5 0.1 0.3 0.2 0.0 0.1 99.7 101, 0 100.0 35.9 35.0 30.6 40.5 45.9 44.7

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Calorific values, calculated 19 900 26 700 23 5OO Gross, KJ / m ³ (534) (717) (630) (Gross, Btu / SCF) 18 400 24 700 21 600 Net, KJ / m ³ (494) (663) (580) (Net, Btu / SCF)

calculated with CO ₂ and

Gross , KJ / m " 41 5OO 46 0OO 57 100 (Big , Btu / SCF) (1 113) (1 234) (995) Net, KJ / m ³ 38 400 42 400 34 300 (Net, Btu / SCF) (1 029) (1 138) (920)

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The artificial carbon particles from the retort 20 are transferred to the carburetor 30. The carburetor 30 can any air-blown gasifier such as a fluidized bed, a dust flow, or a moving bed, each with or be without a catalyst. The temperature at which the gasification takes place is not particularly critical.

In the preferred exemplary embodiment, the gasifier 30 is an air-blown fluidized bed gasifier that operates at moderate pressure (e.g., 2.4 to 15 bar, 20 to 200 psig). The char (char) enters into the carburetor 30 at a temperature between 455 and 48O ° C (850 to 900 ⁰ F). The air and steam to feed the gasifier 30 are at a temperature of about 320 ° C (600 F) and the steam to O ₂ ratio is about 2.6. The gasification results in a combustible gas having a temperature of approximately 930 ° C (1700 ° F) and this gas is taken from the top of the gasifier. The ash obtained is removed from the lower part and discarded. The gas exits the gasifier 30 and passes through the heat exchanger 32 which generates steam; some of the steam is used in the carburetor 30. The combustible gas continues to by-product recovery unit 34 which, by any of the conventional methods, removes undesirable constituents such as sulfur and ammonia and provides the desired combustible gas having a lower BTU value. This combustible gas is composed of approximately 25.3% H-, 20.9% CO, 11.1% CO ₂ , 1.7% CH ₄ and 41% N ₂ and has a gross calorific value of about 166 BTU / SCF . By the term "low BTU gas" is meant a gas which contains very little, if any, high BTU gases such as methane and a comparatively large amount of low BTU gases such as H ₂ and CO.

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The low BTU gas is for many purposes is applicable, and in a preferred exemplary embodiment, the gas is low BTU mixed with a gas from the pyrolysis zone with a high BTU value and results in a gas with a medium BTU value, which has a calorific value of around 250 BTU per standard cubic foot.

In another preferred embodiment, at least a portion of the low BTU gas through heat exchanger 36 used to cool the byproduct water recovery unit 34 contributes flowing combustible gas and accordingly the gas before its entry into which the combustion burner 52 adjacent to the gas turbine 54 is heated again. It is desirable that the gas is sewn into the burner 52 at 19.6 bar (280 psia).

that the gas in the burner 52 is at approximately 205 C (400 F)

Air is pressurized to about 14 bar (200 psia) in compressor 58 and some of that air becomes fed into another air compressor 42, which in turn, the air is compressed even further (to about 28 bar or 400 psia), and this compressed air becomes mixed in steam and used with the 30 carburetor. It is noted that the air compressor 42 based on the Carburetor 30 exerts high pressure, its energy through turbine 40 from part of the in the heat exchanger generated steam receives. The spent steam from turbine 40 flows through condenser 44 and is through the pump 46 discharged as condensate.

Another portion of the compressed air from the air compressor 58 is fed into the combustion burner 52 for use in the combustion turbine 54 which generates both electrical power and the air compressor

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58 drives.

If necessary, some of the steam generated in the heat exchanger 32 can be used to generate additional energy are fed into the auxiliary steam turbine 60. The out The steam discharged from the turbine 6O is passed through the condenser 62 and can either be used as condensate be discharged or, as an alternative, the condensate is fed into the heat exchanger 66 via the pump 64 fed to generate steam again for recycling in the turbine 60. The heat exchanger 66 is with the discharged, but still hot exhaust gas from the gas turbine 54 is supplied.

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■ if.

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Claims (10)

PAT. NT-XNV. A.lTF DR. DIETER V. BEZOLD DIPL. ING. PETER SCHÜTZ DIPL. ING. WOLFGANG HEUSLER MARlA-THERESIA-STRASbE 22 POST BOX 86 0 2 6 0 D-8OOO MUENCHEN O6 US-Ser.No. 115.116 Filed January 24, 1980 TELEPHONE 089/47 69 <7 68 FROM SEPT. 1980: 4706006 TELEX 522638 TELEGRAM SOMBEZ 10 931 Dr.v.B./V/m Case 36-237 Tosco Corporation 10 100 Santa Monica Blvd. Los Angeles, Calif. 90067, V.St.Λ. Process for the production of a combustible pure gas from coal Patent claims 1. Process for coal gasification by pyrolysis of Coal and gasification of the obtained artificial coal with steam and an oxygen-containing gas, characterized by the following stages: 130052/0423 nachqerbchtI ■ a) Pyrolyzing carbon particles containing volatile combustible material by contacting the carbon particles in a non-oxidizing atmosphere with heat-laden solids at a temperature of 370 ° C (700 ° F) to 815 ° C (150O ⁰ F), preferably 43O ° C (800 ⁰ F) to 54O ° C (1OOO ° F) in a pyrolysis zone to convert substantially all teerbildende, volatile, flammable material from the coal particles and to remove volatile vapors, condensable gases and partially devolatilized artificial To produce coal particles, wherein the volatile, combustible material remaining in the coal particles partially freed from volatile constituents contains essentially no condensable tar material and wherein the artificial coal particles partially freed from volatile constituents are essentially non-inflating, b) Separating the artificial charcoal particles, some of which have been freed from volatile constituents, from the heat-laden particles Solids and volatile vapors and condensable gases, c) Transferring the separated, partially freed from volatile constituents, artificial charcoal particles into a gasification zone, d) Contacting the partially volatilized charcoal particles in the gasification zone with steam and an oxygen-containing gas at a temperature of 540 C (1000 F) to 137O ° C (250O ⁰ F) to remove the remaining volatile combustible material from the partially to volatilize artificial charcoal particles freed from volatile constituents and to remove the carbon in the partial 130052/0423 wise to convert volatile carbon particles freed from volatile components with steam, creating an im substantial tar-free combustible gas and ash is produced, and e) separating the substantially tar-free combustible gas from the ash. 2. The method according to claim 1, characterized in that there is an additional stage and prior to the pyrolysis step, place the coal particles in a drying zone to a temperature of 93 ° C (200 ° F) Heated to 316 C (600 F) to remove substantially all of the moisture from the carbon particles, however without removing any significant portion of the volatile combustible material in the carbon particles. 3. The method according to claim 1, characterized in that in a further stage the separated heat-laden solids are recycled back to the pyrolysis zone after being in a solids heater have been reheated. 4. The method according to claim 1, characterized in that there is an additional stage the volatile vapors and condensable gases generated in the pyrolysis zone in a recovery zone separates, so that a high-BTU oil and gas are formed therefrom. 5. The method according to claim 1, characterized in that in further stages the im substantial tar-free combustible gas from the gasification zone can flow through a heat exchanger to generate steam and part of the steam from the heat 130052/0423 exchange feeds into the gasification zone. 6. The method according to claim 5, characterized in that in a further stage another part of the steam from the heat exchanger of a steam turbine to drive a compressor, the feeds the oxygen-containing gas into the gasification zone, feeds. 7. The method according to claim 5, characterized in that in a further stage another part of the steam from the heat exchanger of an auxiliary steam turbine for generating electrical Supplies electricity. 8. The method according to claim 1, characterized in that in a further stage the substantially tar-free combustible gas from the gasification zone to a by-product recovery unit to remove any sulfur and ammonia and a clean burning gas with lower BTU value to-form. 9. The method according to claim 8, characterized in that in a further process stage some of the low BTU gas from the by-product recovery unit mixes the high BTU gas from the recovery zone to form a mid-BTU gas. 10. The method according to claim 8, characterized in that one in v / more stages Part of the low BTU gas from the Nebon Product Recovery Unit pour to a burner 130052/0423 leaves to form a combustion gas, and the combustion gas of a combustion gas turbine to generate of electric current supplies. 130052/0423