CN113025366A - System and method for treating direct coal liquefaction residues - Google Patents
System and method for treating direct coal liquefaction residues Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 51
- 239000000203 mixture Substances 0.000 claims abstract description 111
- 239000007788 liquid Substances 0.000 claims abstract description 94
- 238000002309 gasification Methods 0.000 claims abstract description 54
- 238000000926 separation method Methods 0.000 claims abstract description 41
- 238000000194 supercritical-fluid extraction Methods 0.000 claims abstract description 37
- 238000000227 grinding Methods 0.000 claims abstract description 31
- 238000000605 extraction Methods 0.000 claims abstract description 23
- 238000001035 drying Methods 0.000 claims abstract description 15
- 239000007789 gas Substances 0.000 claims description 40
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Substances N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 21
- 238000003801 milling Methods 0.000 claims description 18
- 230000008569 process Effects 0.000 claims description 18
- 238000012545 processing Methods 0.000 claims description 18
- 239000003795 chemical substances by application Substances 0.000 claims description 13
- 238000002156 mixing Methods 0.000 claims description 13
- 229910052757 nitrogen Inorganic materials 0.000 claims description 13
- 150000001335 aliphatic alkanes Chemical class 0.000 claims description 12
- OFBQJSOFQDEBGM-UHFFFAOYSA-N Pentane Chemical compound CCCCC OFBQJSOFQDEBGM-UHFFFAOYSA-N 0.000 claims description 10
- QWTDNUCVQCZILF-UHFFFAOYSA-N isopentane Chemical compound CCC(C)C QWTDNUCVQCZILF-UHFFFAOYSA-N 0.000 claims description 10
- 239000000843 powder Substances 0.000 claims description 9
- 238000007664 blowing Methods 0.000 claims description 8
- NNPPMTNAJDCUHE-UHFFFAOYSA-N isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 claims description 8
- CRSOQBOWXPBRES-UHFFFAOYSA-N neopentane Chemical compound CC(C)(C)C CRSOQBOWXPBRES-UHFFFAOYSA-N 0.000 claims description 8
- 238000004891 communication Methods 0.000 claims description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 6
- 239000001301 oxygen Substances 0.000 claims description 6
- 229910052760 oxygen Inorganic materials 0.000 claims description 6
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims description 5
- AFABGHUZZDYHJO-UHFFFAOYSA-N dimethyl butane Natural products CCCC(C)C AFABGHUZZDYHJO-UHFFFAOYSA-N 0.000 claims description 5
- 239000003546 flue gas Substances 0.000 claims description 5
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 claims description 5
- 238000010298 pulverizing process Methods 0.000 claims description 5
- 239000001282 iso-butane Substances 0.000 claims description 4
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 claims description 4
- 230000015572 biosynthetic process Effects 0.000 abstract description 18
- 238000003786 synthesis reaction Methods 0.000 abstract description 18
- 150000004767 nitrides Chemical class 0.000 abstract description 2
- 150000003568 thioethers Chemical class 0.000 abstract description 2
- 239000002699 waste material Substances 0.000 abstract description 2
- 239000003921 oil Substances 0.000 description 26
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 22
- 239000000706 filtrate Substances 0.000 description 16
- 239000002002 slurry Substances 0.000 description 11
- 239000000047 product Substances 0.000 description 8
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- 229910052799 carbon Inorganic materials 0.000 description 5
- 239000003034 coal gas Substances 0.000 description 5
- 230000036284 oxygen consumption Effects 0.000 description 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 4
- 239000010426 asphalt Substances 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- 239000011593 sulfur Substances 0.000 description 4
- 229910052717 sulfur Inorganic materials 0.000 description 4
- 239000004566 building material Substances 0.000 description 3
- 239000003054 catalyst Substances 0.000 description 3
- 238000011143 downstream manufacturing Methods 0.000 description 3
- 239000000295 fuel oil Substances 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
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- VLKZOEOYAKHREP-UHFFFAOYSA-N n-Hexane Chemical compound CCCCCC VLKZOEOYAKHREP-UHFFFAOYSA-N 0.000 description 2
- 239000002893 slag Substances 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000011449 brick Substances 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 238000004517 catalytic hydrocracking Methods 0.000 description 1
- 238000002485 combustion reaction Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 239000002920 hazardous waste Substances 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 231100000989 no adverse effect Toxicity 0.000 description 1
- 238000003825 pressing Methods 0.000 description 1
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- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10G1/00—Production of liquid hydrocarbon mixtures from oil-shale, oil-sand, or non-melting solid carbonaceous or similar materials, e.g. wood, coal
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
- C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
- C10J3/46—Gasification of granular or pulverulent flues in suspension
- C10J3/48—Apparatus; Plants
- C10J3/485—Entrained flow gasifiers
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Chemistry (AREA)
- Combustion & Propulsion (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
The invention relates to the field of coal direct liquefaction residue treatment, in particular to a system and a method for treating coal direct liquefaction residue. The system comprises: the supercritical extraction unit is used for extracting the direct coal liquefaction residues to obtain an extraction liquid and a solid-liquid mixture; the solid-liquid separation unit is used for carrying out solid-liquid separation on the solid-liquid mixture to obtain raffinate; the grinding unit is used for drying and grinding the raffinate and the raw coal to obtain a first powdery mixture; and the gasification unit is used for gasifying the first powdery mixture. The system and the method not only efficiently recover the high value-added oil product in the direct coal liquefaction residue, but also improve the gasification efficiency and the yield of the synthesis gas, reduce the emission of sulfides and nitrides, realize the treatment of the direct coal liquefaction residue and maximally reduce the emission of wastes.
Description
Technical Field
The invention relates to the field of coal direct liquefaction residue treatment, in particular to a system and a method for treating coal direct liquefaction residue.
Background
Coal is directly liquefied, one of the coal liquefaction methods is a process of converting coal into liquid fuel through hydrocracking under the action of hydrogen and a catalyst. Besides obtaining the required liquefied product in the direct coal liquefaction process, some hydrocarbon molecules and CO can be generatedxGas, process water and liquefaction residues (also called coal direct liquefaction residues) generated in the solid-liquid separation process.
The direct coal liquefaction residue is solid hazardous waste and mainly contains inorganic substances and organic substances, wherein the organic substances comprise liquefied heavy oil, asphalt substances and unconverted coal, and the inorganic substances comprise mineral substances in the coal and an additional catalyst.
How to reasonably and efficiently utilize the direct coal liquefaction residues is a difficult problem which needs to be solved urgently by a coal liquefaction process. There are many methods for treating coal direct liquefaction residues as reported in the following prior art.
CN103923703B discloses a method for producing crude synthesis gas by using coal direct liquefaction residue as raw material, which comprises the following steps: s1, preparing coal water slurry from the direct coal liquefaction residues; and S2, mixing the coal water slurry with oxygen to carry out gasification reaction to obtain crude synthesis gas. The method not only realizes the full and efficient utilization of the direct coal liquefaction residues, but also converts the sulfur with higher content in the direct coal liquefaction residues into H in the gasification process2S and the recovery treatment is carried out in the subsequent crude synthesis gas purification process, so that the high-efficiency utilization process has no pollution to the environment, the added value of the product is high, the treatment process is simple, and no adverse effect is caused on the operation of equipment; meanwhile, because the heat value of the direct coal liquefaction residue is high, and the Fe-based catalyst which is required by coal liquefaction and is enriched in the direct coal liquefaction residue has a catalytic effect on the coal gasification process, the content of effective gas components in the finally obtained crude synthesis gas is high. The method adopts coal to directly liquefy residues, modified oil and raw coalThe synthesis gas is prepared by gasifying the coal water slurry, the liquefied residue oil product is not effectively recovered, and the effective gas component and the cold gas efficiency of the coal water slurry gasification are lower.
CN103695057B discloses a method for preparing coal water slurry by directly liquefying coal, the prepared coal water slurry and a gasification method thereof. The method for preparing the coal water slurry by using the direct coal liquefaction residues comprises the following steps: s1, extracting the direct coal liquefaction residues, carrying out solid-liquid separation, and drying to obtain an extract residue; and S2, crushing and grinding the raffinate, adding water and an optional surfactant into the raffinate, and stirring to obtain the coal water slurry. After the coal direct liquefaction residue is extracted, heavy oil and asphalt substances in the coal direct liquefaction residue can be separated from unconverted coal and ash, and the unconverted coal and the ash are collectively called raffinate. The coal water slurry can be formed after crushing and grinding the raffinate and adding water and optional surfactant. The coal water slurry can be used as common fuel and can be used in gasification production. Therefore, the raffinate of the direct coal liquefaction residue is effectively utilized, and the utilization rate and the added value of the direct coal liquefaction residue are improved. But the method adopts extracting agents such as tetrahydrofuran, direct coal liquefaction oil and the like at the temperature of between 0.1 and 1.0MPa and between 80 and 280 ℃ and H2Or N2Heavy oil and asphalt substances in the extracted coal direct liquefaction residue are possibly incompletely extracted under the environment, so that the subsequent raffinate has high cohesiveness; in addition, the content of sulfur and nitrogen in the liquefaction residue is higher; in addition, the method adopts a coal water slurry gasification mode, the gasification effective gas components and the cold coal gas efficiency are low, and the direct coal liquefaction residue is not fully utilized.
However, the above methods all have the problems of low oil extraction rate of coal direct liquefaction residue, insufficient utilization of residue raffinate, and the like, and therefore, a method for efficiently treating coal direct liquefaction residue is urgently needed.
Disclosure of Invention
The invention aims to solve the problems of low oil extraction rate of coal direct liquefaction residue, insufficient utilization of residue raffinate and the like in the prior art, and provides a system and a method for treating the coal direct liquefaction residue.
In order to achieve the above object, a first aspect of the present invention provides a system for treating a coal direct liquefaction residue, comprising:
the supercritical extraction unit is used for extracting the direct coal liquefaction residues to obtain an extraction liquid and a solid-liquid mixture;
the solid-liquid separation unit is used for carrying out solid-liquid separation on the solid-liquid mixture to obtain raffinate;
the grinding unit is used for drying and grinding the raffinate and the raw coal to obtain a first powdery mixture;
and the gasification unit is used for gasifying the first powdery mixture.
In a second aspect, the present invention provides a method for treating coal direct liquefaction residues, comprising:
(1) performing supercritical extraction on the direct coal liquefaction residues by using an extracting agent to obtain an extract and a solid-liquid mixture;
(2) carrying out solid-liquid separation on the solid-liquid mixture to obtain an extract;
(3) mixing the extraction residues and the raw coal in proportion, drying and grinding to obtain a first powdery mixture;
(4) gasifying the first powdery mixture.
In a third aspect, the present invention provides a method for treating a coal direct liquefaction residue using the system of the second aspect of the present invention, comprising:
(I) extracting the direct coal liquefaction residues in a supercritical extraction unit to obtain an extract and a solid-liquid mixture;
(II) carrying out solid-liquid separation on the solid-liquid mixture in a solid-liquid separation unit to obtain raffinate;
(III) mixing the raffinate and the raw coal in proportion, and drying and grinding the mixture in a grinding unit to obtain a first powdery mixture;
(IV) gasifying the first powdered mixture in a gasification unit;
preferably, the first pulverized mixture is gasified in a dry pulverized coal entrained flow gasifier.
The system and the method not only efficiently recover high value-added oil products in the direct coal liquefaction residues, but also improve the gasification process efficiency and the yield of synthesis gas, reduce the emission of sulfides and nitrides, carry out thorough 'dry-pressing clean' treatment on the direct coal liquefaction residues, and maximally reduce the emission of wastes. In addition, the system and the method have the advantages of high oil recovery rate, small cohesiveness of the produced raffinate, and low nitrogen and sulfur contents; high yield of gasified synthesis gas, high efficiency of cold gas and the like.
Drawings
FIG. 1 is a schematic diagram illustrating one embodiment of the system of the present invention.
Description of the reference numerals
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2 | Solid- |
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| 5 | |
6 | Oil |
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8 | Ash and slag treating sheetYuan |
Detailed Description
The endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.
The invention provides a system for processing direct coal liquefaction residues, which comprises:
the supercritical extraction unit is used for extracting the direct coal liquefaction residues to obtain an extraction liquid and a solid-liquid mixture;
the solid-liquid separation unit is used for carrying out solid-liquid separation on the solid-liquid mixture to obtain raffinate;
the grinding unit is used for drying and grinding the raffinate and the raw coal to obtain a first powdery mixture;
and the gasification unit is used for gasifying the first powdery mixture.
According to the invention, preferably, the outlet of the supercritical extraction unit is in communication with the inlet of the solid-liquid separation unit, and the raffinate outlet of the solid-liquid separation unit is in communication with the inlet of the milling unit.
According to the present invention, preferably the extractant arranged in the supercritical extraction unit is selected from the group consisting of C3-C8 alkanes or mixtures thereof, preferably C4-C6 alkanes or mixtures thereof, more preferably from the group consisting of n-pentane, n-butane, isobutane, isopentane, neopentane, and mixtures thereof.
According to the invention, the coal direct liquefaction residue is extracted in a supercritical extraction unit to obtain an upper clear extraction liquid and a lower solid-liquid mixture. Here, the solid-liquid mixture is a mixture of a solid residue and a small amount of liquid.
According to the invention, the solid-liquid mixture is subjected to solid-liquid separation in a solid-liquid separation unit to obtain raffinate and a small amount of filtrate.
According to the invention, the raffinate and the raw coal are dried and milled in a milling unit to obtain a first powdery mixture. Preferably, in the milling unit, an air blowing device is provided for blowing air to the milling system during milling.
Preferably, the system further comprises a conveying unit for conveying the first powdered mixture into the gasification unit, more preferably, the conveying unit is in communication with the outlet of the milling unit and the inlet of the gasification unit.
According to the invention, in the gasification unit, the first pulverulent mixture is subjected to a gasification reaction to produce synthesis gas and, at the same time, ash.
According to the present invention, preferably, the gasification unit is a dry coal powder entrained flow gasifier.
Preferably, the first powdery mixture contains particles having a particle diameter of 90 μm or more in a volume content of not more than 10%. Preferably, the gasifier lining of the gasification unit is a waterwall, refractory brick or a mixture of both, preferably a waterwall.
Preferably, the system further comprises a syngas purification unit for receiving the syngas generated by the gasification unit for further purification treatment.
Preferably, the system further comprises an oil deep processing unit for receiving the extract of the supercritical extraction unit and the filtrate of the solid-liquid separation unit for deep processing treatment.
Preferably, the system further comprises an ash handling unit for handling ash produced by the gasification unit.
In a second aspect, the present invention provides a method of treating a coal direct liquefaction residue, comprising:
(1) performing supercritical extraction on the direct coal liquefaction residues by using an extracting agent to obtain an extract and a solid-liquid mixture;
(2) carrying out solid-liquid separation on the solid-liquid mixture to obtain an extract;
(3) mixing the extraction residues and the raw coal in proportion, drying and grinding to obtain a first powdery mixture;
(4) gasifying the first powdery mixture.
According to the present invention, preferably, in step (1), the extractant is selected from the group consisting of C3-C8 alkanes or mixtures thereof; the extraction conditions include: the temperature is 150 ℃ and 300 ℃, and the pressure is 4-12 MPa.
More preferably, the extractant is selected from the group consisting of C4-C6 alkanes or mixtures thereof, for example selected from the group consisting of n-pentane, n-butane, isobutane, isopentane, neopentane, and mixtures thereof.
More preferably, the extraction conditions include: the temperature is 200 ℃ and 250 ℃, and the pressure is 4-8 MPa.
Preferably, the mass ratio of the extracting agent to the coal direct liquefaction residue is (3-15):1, preferably (5-10): 1.
In a preferred embodiment, the extractant is selected from the group consisting of C4-C6 alkanes and mixtures thereof, and the extraction conditions include: the temperature is 200 ℃ and 250 ℃, the pressure is 4-8MPa, and the mass ratio of the extracting agent to the direct coal liquefaction residue is (5-10): 1.
Extracting by supercritical extraction to obtain an extract and a solid-liquid mixture. Here, the solid-liquid mixture is a mixture of a solid residue and a small amount of liquid.
According to the invention, in the step (2), the solid-liquid mixture obtained by the supercritical extraction is subjected to solid-liquid separation to obtain raffinate and a small amount of filtrate.
According to the invention, in the step (3), the raffinate and the raw coal are mixed in proportion and ground, preferably, the mass ratio of the raffinate to the raw coal is 1 (1-100), preferably 1: (3-20).
In one embodiment, the milling is performed in a mill, more preferably the mill is a roller disc mill.
In order to obtain a powder having a small particle size suitable for gasification of dry pulverized coal, it is preferable to blow hot air during the pulverization. More preferably, the hot air is nitrogen, flue gas, or a mixed gas of air and nitrogen, wherein the oxygen content is less than 8 vol%.
In order to further obtain powder with smaller particle size, preferably, the inlet temperature of the hot air is 140-300 ℃, and the outlet temperature of the hot air is 35-100 ℃; further preferably, the inlet temperature of the hot air is 150-200 ℃ and the outlet temperature of the hot air is 40-80 ℃.
Preferably, the amount of inlet hot air required per 1kg of throughput is 0.5-5Nm3Preferably 1-3Nm3. Here, the throughput is the weight of the mixture of the raffinate and the raw coal.
Preferably, the pressure difference between the hot air inlet and the hot air outlet is not more than 2000 Pa.
Preferably, the first powdery mixture obtained by milling has a total water content of not more than 6%.
More preferably, the first powdery mixture contains particles having a particle diameter of 90 μm or more in a volume content of not more than 10%. In this context, the particle volume content is determined by a laser particle size analyzer sampling test.
In a preferred embodiment, the inlet temperature of the hot air is 150-; the first powdery mixture has a total water content of 2-4% and a volume content of particles having a particle diameter of 75 μm or more of not more than 10%
Preferably, in step (4), the gasification is carried out in a dry coal powder entrained flow gasifier.
Preferably, the conditions of the gasification include: the pressure is 0.1-10MPa, preferably 3-6MPa, the temperature is 1000-1600 ℃, and preferably 1250-1500 ℃.
Preferably, the synthesis gas generated by gasification enters a downstream process after being purified, and the ash generated by gasification can be used for building material processing after being treated by ash.
According to the present invention, preferably, the method further comprises subjecting the extract liquid produced in the extraction process and the filtrate produced in the solid-liquid separation process to oil deep processing treatment, for example, oil deep processing treatment in an oil deep processing unit, to obtain a product oil. Wherein, the extracting agent removed from the extracting solution and the filtrate can be recycled for the supercritical extraction process.
In a third aspect, the present invention provides a method for treating coal direct liquefaction residues by using the system of the first aspect of the present invention, comprising:
(I) extracting the direct coal liquefaction residues in a supercritical extraction unit to obtain an extract and a solid-liquid mixture;
(II) carrying out solid-liquid separation on the solid-liquid mixture in a solid-liquid separation unit to obtain raffinate;
(III) mixing the raffinate and the raw coal in proportion, and grinding the mixture in a grinding unit to obtain a first powdery mixture;
(IV) gasifying the first powdered mixture in a gasification unit;
preferably, the first pulverized mixture is gasified in a dry pulverized coal entrained flow gasifier.
According to the invention, in step (I), the extractant of the supercritical extraction unit arrangement is selected from C3-C8 alkanes or mixtures thereof; more preferably, the extractant is selected from the group consisting of C4-C6 alkanes or mixtures thereof, for example selected from the group consisting of n-pentane, n-butane, isobutane, isopentane, neopentane, and mixtures thereof.
Preferably, the extraction conditions include: the temperature is 150 ℃ and 300 ℃, and the pressure is 4-12 MPa; more preferably comprises: the temperature is 200 ℃ and 250 ℃, and the pressure is 4-8 MPa.
Preferably, the mass ratio of the extracting agent to the coal direct liquefaction residue is (3-15):1, preferably (5-10): 1.
In a preferred embodiment, the extractant is selected from the group consisting of C4-C6 alkanes and mixtures thereof, and the extraction conditions include: the temperature is 200 ℃ and 250 ℃, the pressure is 4-8MPa, and the mass ratio of the extracting agent to the direct coal liquefaction residue is (5-10): 1.
Extracting by supercritical extraction to obtain an extract and a solid-liquid mixture. Here, the solid-liquid mixture is a mixture of a solid residue and a small amount of liquid.
According to the invention, in the step (II), the solid-liquid mixture obtained by the supercritical extraction unit is introduced into a solid-liquid separation unit for solid-liquid separation, so that raffinate and a small amount of filtrate are obtained.
Preferably, in the step (III), the mass ratio of the raffinate to the raw coal is 1 (1-100), preferably 1: (3-20).
Preferably, hot air is blown in during the milling process; preferably, the hot air is nitrogen, flue gas, or a mixed gas of air and nitrogen, wherein the oxygen content is less than 8 vol%.
In order to further obtain powder with smaller particle size, preferably, the inlet temperature of the hot air is 140-300 ℃, and the outlet temperature of the hot air is 35-100 ℃; further preferably, the inlet temperature of the hot air is 150-200 ℃ and the outlet temperature of the hot air is 40-80 ℃.
Preferably, the amount of inlet hot air required per 1kg of throughput is 0.5-5Nm3Preferably 1-3Nm3. Here, the throughput is the weight of the mixture of the raffinate and the raw coal.
Preferably, the pressure difference between the hot air inlet and the hot air outlet is not more than 2000 Pa.
Preferably, the first powdery mixture obtained by milling has a total water content of not more than 6%.
More preferably, the first powdery mixture contains particles having a particle diameter of 90 μm or more in a volume content of not more than 10%.
In a preferred embodiment, the inlet temperature of the hot air is 150-; the first powdery mixture thus obtained has a total water content of 2 to 4% and a volume content of particles having a particle diameter of 75 μm or more of not more than 10%.
Preferably, in step (IV), the gasification unit is a dry coal powder entrained flow gasifier.
Preferably, the conditions of the gasification include: the pressure is 0.1-10MPa, preferably 3-6MPa, the temperature is 1000-1600 ℃, and preferably 1250-1500 ℃.
Preferably, the synthesis gas generated by gasification is introduced into a synthesis gas purification unit for synthesis gas purification treatment and then enters a downstream process, and the ash generated by gasification is introduced into an ash treatment unit for ash treatment and then is used for building material processing.
According to the invention, preferably, the method further comprises introducing the extract liquid produced by the supercritical extraction unit and the filtrate produced by the solid-liquid separation unit into an oil product deep processing unit for oil product deep processing treatment to obtain the finished oil. Wherein, the extracting agent removed from the extracting solution and the filtrate can be recycled to the supercritical extraction unit for the supercritical extraction process.
The specific definitions of the steps of the process according to the second aspect of the invention apply equally to the process according to the third aspect of the invention, and are not to be considered superfluous here.
Fig. 1 shows a schematic diagram of an embodiment of the system according to the present invention, which comprises:
the system comprises a supercritical extraction unit 1, a solid-liquid separation unit 2, a grinding unit 3, a gasification unit 4, a conveying unit 5, an oil deep processing unit 6, a synthetic gas purification unit 7 and an ash treatment unit 8. The method for treating the direct coal liquefaction residue by using the system comprises the following steps:
(a) introducing the coal direct liquefaction residue into a supercritical extraction unit 1, and extracting by using an extracting agent selected from C3-C8 alkane or a mixture thereof; the mass ratio of the extracting agent to the direct coal liquefaction residue is (3-15) to 1, and the extraction conditions comprise: the temperature is 150 ℃ and 300 ℃, and the pressure is 4-12MPa, so as to obtain an extraction liquid and a solid-liquid mixture;
(b) introducing the solid-liquid mixture into a solid-liquid separation unit 2 for solid-liquid separation to obtain raffinate and a small amount of filtrate, introducing the small amount of filtrate and extract into an oil deep processing unit 6 for further treatment to obtain finished oil, wherein an extractant removed in the oil deep processing unit 6 can be circularly used in a supercritical extraction unit 1;
(c) introducing the raffinate and the raw coal (the mass ratio of the raffinate to the raw coal is 1 (1-100)) into a grinding unit 3 for drying and grinding, wherein the conditions for drying and grinding comprise: blowing hot air in the milling process, wherein the hot air is preferably nitrogen, flue gas or mixed gas of air and nitrogen, and the content of oxygen is less than 8% by volume; preferably, the inlet temperature of the hot air is 140-300 ℃, and the outlet temperature of the hot air is 35-100 ℃; preferably, the amount of inlet hot air required per 1kg of throughput is 0.5-5Nm3(ii) a Preferably, the pressure difference between the hot air inlet and the hot air outlet is not more than 2000Pa, so as to obtain a first powdery mixture, wherein the total water content of the first powdery mixture is not more than 6%, and the volume content of particles with the particle size of more than 90 mu m is not more than 10%.
(d) Introducing the first powdery mixture into a gasification unit 4 through a conveying unit 5 for gasification, wherein the gasification conditions comprise: the pressure is 0.1-10MPa, the temperature is 1000-1600 ℃, the generated synthesis gas is introduced into a synthesis gas purification unit 7 for treatment so as to be used in downstream processes, and the generated ash is introduced into an ash treatment unit 8 for treatment and then is used for building material processing.
Compared with the prior art, the method has the following advantages:
(i) by adopting the supercritical extraction process, the recovery rate of oil products in the coal direct liquefaction residues is high, the content of heavy asphalt oil in the extraction residues is low, so that the slag bonding property of the extraction residues is low, and the contents of nitrogen and sulfur in the extraction residues are low;
(ii) the adjustable proportion of raw coal and raffinate in the process is large, and the process flexibility is good;
(iii) the process parameter control of the mixed coal grinding of the raffinate and the raw coal can effectively prevent the mixture from spontaneous combustion and control the CO concentration to be lower than 10 ppm;
(iv) the dry pulverized coal gasification mode is adopted for gasification, so that the gasification efficiency can be effectively improved.
The present invention will be described in detail below by way of examples.
Example 1
Mixing the direct coal liquefaction residue (150kg/h) with n-pentane according to the solid-liquid mass ratio of 1:4, and performing supercritical extraction in a supercritical extraction unit 1 at 200 ℃ and 4MPa to obtain an extract and a solid-liquid mixture.
And (3) carrying out solid-liquid separation on the solid-liquid mixture in a solid-liquid separation unit 2 to obtain raffinate (83.5kg/h) and filtrate, and carrying out deep processing treatment on the extract and the filtrate to obtain finished oil (64.5 kg/h).
Mixing the raffinate and raw coal at a mass ratio of 1:12, feeding into a coal grinding unit 3, and blowing hot air during grinding, wherein the inlet temperature of the hot air is 180 ℃, the outlet temperature of the hot air is 50 ℃, and the inlet hot air amount required by the treatment capacity of 1kg is 3Nm3The pressure difference between the inlet and outlet of the hot air was 1200Pa, and a first powdery mixture (containing 2.3% of total water and 5% by volume of particles having a particle diameter of 75 μm or more) was obtained.
The first powdery mixture is sent to a gasification unit 4 through a conveying unit 5 to be gasified by dry pulverized coal, and the gasification conditions comprise that: the pressure is 4MPa, the temperature is 1350 ℃, and the synthesis gas is obtained.
The content of the effective gas of the finally obtained synthetic gas is 86 percent, the carbon conversion rate is 99 percent, the cold coal gas efficiency is 82 percent, and the specific oxygen consumption is 330kg/kNm3(CO+H2) The specific coal consumption is 560kg/kNm3(CO+H2)。
Example 2
Mixing the direct coal liquefaction residue (200kg/h) with isopentane according to the solid-liquid mass ratio of 1:5, and performing supercritical extraction in a supercritical extraction unit 1 at the temperature of 200 ℃ and the pressure of 5MPa to obtain an extract liquid and a solid-liquid mixture.
And (3) carrying out solid-liquid separation on the solid-liquid mixture in a solid-liquid separation unit 2 to obtain raffinate (102.5kg/h) and filtrate, and treating the extract and the filtrate to obtain finished oil (91 kg/h).
Mixing the raffinate and raw coal (in a mass ratio of 1: 7), feeding into a coal grinding unit 3, and blowing hot air during grinding, wherein the inlet temperature of the hot air is 200 ℃, the outlet temperature of the hot air is 80 ℃, and the inlet hot air amount required by the treatment capacity of 1kg is 2Nm3The pressure difference between the inlet and outlet of the hot air was 1000Pa, and a first powdery mixture (containing 2.1% of total water and 4.3% by volume of particles having a particle diameter of 75 μm or more) was obtained.
The first powdery mixture is sent to a gasification unit 4 through a conveying unit 5 to be gasified by dry pulverized coal, and the gasification conditions comprise that: the pressure is 4MPa, the temperature is 1350 ℃, and the synthesis gas is obtained.
The content of the effective gas of the finally obtained synthetic gas is 86 percent, the carbon conversion rate is 99 percent, the cold coal gas efficiency is 83 percent, and the specific oxygen consumption is 324kg/kNm3(CO+H2) Specific coal consumption is 548kg/kNm3(CO+H2)。
Example 3
Mixing the direct coal liquefaction residue (250kg/h) and n-hexane according to the solid-liquid mass ratio of 1:4, and performing supercritical extraction in a supercritical extraction unit 1 at 250 ℃ and 4MPa to obtain an extract and a solid-liquid mixture.
And (3) carrying out solid-liquid separation on the solid-liquid mixture in a solid-liquid separation unit 2 to obtain raffinate (131.5kg/h) and filtrate, and treating the extract and the filtrate to obtain finished oil (115 kg/h).
Mixing the raffinate and raw coal at a mass ratio of 1:5, feeding into a coal grinding unit 3, blowing hot air during grinding, wherein the inlet temperature of the hot air is 150 ℃, the outlet temperature of the hot air is 40 ℃, the outlet temperature of the hot air is 50 ℃, and the inlet hot air amount required by the treatment capacity of 1kg is 2Nm3The pressure difference between the inlet and outlet of the hot air was 800Pa, and a first powdery mixture (containing 1.6% of total water and 3.5% by volume of particles having a particle diameter of 75 μm or more) was obtained.
The first powdery mixture is sent to a gasification unit 4 through a conveying unit 5 to be gasified by dry pulverized coal, and the gasification conditions comprise that: the pressure is 4MPa, the temperature is 1350 ℃, and the synthesis gas is obtained.
The content of the effective gas of the finally obtained synthetic gas is 87 percent, the carbon conversion rate is 99 percent, the cold coal gas efficiency is 84 percent, and the specific oxygen consumption is 312kg/kNm3(CO+H2) Specific coal consumption of 536kg/kNm3(CO+H2)。
Example 4
Treating the coal direct liquefaction residue as described in example 1, except that the inlet temperature of hot air of the pulverizing unit was set to 100 ℃ and the outlet temperature was set to 30 ℃; the rest is the same as in example 1. The first powdery mixture finally obtained contained 20% by volume of particles having a particle diameter of 90 μm or more.
The content of the effective gas of the finally obtained synthetic gas is 78 percent, the carbon conversion rate is 98 percent, the cold coal gas efficiency is 78 percent, and the specific oxygen consumption is 366kg/kNm3(CO+H2) Specific coal consumption of 593kg/kNm3(CO+H2)。
Example 5
The direct coal liquefaction residue was treated in the same manner as in example 1, except that hot air was not blown during the pulverization in the pulverizing unit. The first powdery mixture finally obtained contained 100% by volume of particles having a particle diameter of 90 μm or more. Is not suitable for dry coal powder gasification.
Comparative example 1
The coal direct liquefaction residue was treated as described in example 1, except that the supercritical extraction was not performed, and the extraction was performed according to the method described in example 5 of CN103695057B, which was otherwise the same as in example 1.
42kg/h of finally obtained finished oil, 98kg/h of raffinate, 80 percent of effective gas content of gasified synthetic gas, 98 percent of carbon conversion rate, 78 percent of cold gas efficiency and 362kg/kNm of specific oxygen consumption3(CO+H2) Specific coal consumption is 586kg/kNm3(CO+H2)。
The preferred embodiments of the present invention have been described above in detail, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, many simple modifications can be made to the technical solution of the invention, including combinations of various technical features in any other suitable way, and these simple modifications and combinations should also be regarded as the disclosure of the invention, and all fall within the scope of the invention.
Claims (12)
1. A system for processing coal direct liquefaction residues, comprising:
the supercritical extraction unit is used for extracting the direct coal liquefaction residues to obtain an extraction liquid and a solid-liquid mixture;
the solid-liquid separation unit is used for carrying out solid-liquid separation on the solid-liquid mixture to obtain raffinate;
the grinding unit is used for drying and grinding the raffinate and the raw coal to obtain a first powdery mixture;
and the gasification unit is used for gasifying the first powdery mixture.
2. The system of claim 1, wherein the outlet of the supercritical extraction unit is in communication with the solid-liquid separation unit inlet and the raffinate outlet of the solid-liquid separation unit is in communication with the inlet of the milling unit.
3. The system of claim 1, wherein the extractant disposed in the supercritical extraction unit is selected from the group consisting of C3-C8 alkanes or mixtures thereof.
4. The system according to any one of claims 1 to 3, wherein the system further comprises a raw coal crushing and drying unit for crushing and drying raw coal, more preferably, an outlet of the raw coal crushing and drying unit is in communication with an inlet of the pulverizing unit;
preferably, the system further comprises a conveying unit for conveying the first powdered mixture into the gasification unit, more preferably, the conveying unit is in communication with the outlet of the milling unit and the inlet of the gasification unit.
5. The system of any one of claims 1-3, wherein the gasification unit is a dry coal powder entrained flow gasifier;
preferably, the first powdery mixture contains particles having a particle diameter of 90 μm or more in a volume content of not more than 10%.
6. System according to claim 1 or 2, wherein in the milling unit, an air blowing device is provided for blowing air to the milling system during milling.
7. A method of treating coal direct liquefaction residue, comprising:
(1) performing supercritical extraction on the direct coal liquefaction residues by using an extracting agent to obtain an extract and a solid-liquid mixture;
(2) carrying out solid-liquid separation on the solid-liquid mixture to obtain an extract;
(3) mixing the extraction residues and the raw coal in proportion, drying and grinding to obtain a first powdery mixture;
(4) gasifying the first powdery mixture.
8. The process of claim 7, wherein, in step (1), the extractant is selected from the group consisting of C3-C8 alkanes or mixtures thereof;
preferably, the extractant is selected from alkanes of C4-C6 or mixtures thereof;
preferably, the extractant is selected from the group consisting of n-pentane, n-butane, isobutane, isopentane, neopentane, and mixtures thereof;
preferably, the extraction conditions include: the temperature is 150 ℃ and 300 ℃, and the pressure is 4-12 MPa;
preferably, the mass ratio of the extracting agent to the direct coal liquefaction residue is (3-15): 1.
9. The method according to claim 7, wherein in the step (3), the mass ratio of the raffinate to the raw coal is 1 (1-100), preferably 1: (3-20);
preferably, hot air is blown in during the milling process;
preferably, the hot air is nitrogen, flue gas or mixed gas of air and nitrogen, wherein the oxygen content is less than 8% by volume;
preferably, the inlet temperature of the hot air is 140-300 ℃, and the outlet temperature of the hot air is 35-100 ℃;
preferably, the amount of inlet hot air required per 1kg of throughput is 0.5-5Nm3Preferably 1-3Nm3；
Preferably, the pressure difference between an inlet and an outlet of the hot air is not more than 2000 Pa;
preferably, the first powdery mixture contains particles having a particle diameter of 90 μm or more in a volume content of not more than 10%.
10. The method of claim 7, wherein in step (4), the gasification is carried out in a dry coal powder entrained flow gasifier;
preferably, the conditions of the gasification include: the pressure is 0.1-10MPa, and the temperature is 1000-1600 ℃.
11. A method of processing coal direct liquefaction residue using the system of any of claims 1-6, comprising:
(I) extracting the direct coal liquefaction residues in a supercritical extraction unit to obtain an extract and a solid-liquid mixture;
(II) carrying out solid-liquid separation on the solid-liquid mixture in a solid-liquid separation unit to obtain raffinate;
(III) mixing the raffinate and the raw coal in proportion, and drying and grinding the mixture in a grinding unit to obtain a first powdery mixture;
(IV) gasifying the first powdered mixture in a gasification unit;
preferably, the first pulverized mixture is gasified in a dry pulverized coal entrained flow gasifier.
12. The process according to claim 11, wherein in step (III), the mass ratio of the raffinate to the raw coal is 1 (1-100), preferably 1: (3-20);
preferably, hot air is blown in during the milling process;
preferably, the hot air is nitrogen, flue gas or mixed gas of air and nitrogen, wherein the oxygen content is less than 8% by volume;
preferably, the inlet temperature of the hot air is 140-300 ℃, and the outlet temperature of the hot air is 35-100 ℃;
preferably, the amount of inlet hot air required per 1kg of throughput is 0.5-5Nm3Preferably 1-3Nm3；
Preferably, the pressure difference between an inlet and an outlet of the hot air is not more than 2000 Pa;
preferably, the first powdery mixture contains particles having a particle diameter of 90 μm or more in a volume content of not more than 10%.
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| CN104694147A (en) * | 2015-03-19 | 2015-06-10 | 中国矿业大学(北京) | Method of preparing mesophase pitch by extracting direct coal liquefaction residues through supercritical solvent |
| CN108410491A (en) * | 2018-03-14 | 2018-08-17 | 煤炭科学技术研究院有限公司 | A kind of method and system preparing pitch using coal liquefaction residue |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104694147A (en) * | 2015-03-19 | 2015-06-10 | 中国矿业大学(北京) | Method of preparing mesophase pitch by extracting direct coal liquefaction residues through supercritical solvent |
| CN108410491A (en) * | 2018-03-14 | 2018-08-17 | 煤炭科学技术研究院有限公司 | A kind of method and system preparing pitch using coal liquefaction residue |
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