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CN-121991722-A - Preparation method and process system for preparing chemicals by hydrogenating medium-low temperature coal tar

CN121991722ACN 121991722 ACN121991722 ACN 121991722ACN-121991722-A

Abstract

The invention discloses a preparation method and a process system for preparing chemicals by hydrogenating medium-low temperature coal tar, which belong to the technical field of coal chemical industry, the medium-low temperature coal tar is added into a distillation tower for fractionation, the bottom of the distillation tower is fractionated to obtain heavy fraction HO, the top of the distillation tower is fractionated to obtain light fraction LO, adding LO into a first hydrogenation reactor to obtain LOL, adding HO into a second hydrogenation reactor to obtain HOH, adding the LOL and the HOH into a third hydrogenation reactor, and adding the LOL and the HOH into a first rectifying tower and a second rectifying tower to carry out fractional rectification after the reaction is finished to obtain cyclohexane, methylcyclohexane and toluene respectively. By the mode, the medium-low temperature coal tar light fraction and the heavy fraction are subjected to quality-division and grading conversion, so that the full components of the medium-low temperature coal tar are fully utilized, and the method has good economic benefit.

Inventors

  • Me Qiuxiang
  • SUN MING
  • WANG JING
  • SUN GAOYANG

Assignees

  • 西京学院

Dates

Publication Date
20260508
Application Date
20260202

Claims (8)

  1. 1. The preparation method of the chemical product by hydrogenating the medium-low temperature coal tar is characterized by comprising the following steps of: adding medium-low temperature coal tar into a distillation tower (1001) for fractionation, fractionating the coal tar at the bottom of the distillation tower (1001) to obtain a heavy fraction HO, and fractionating the coal tar at the top of the distillation tower (1001) to obtain a light fraction LO; Adding LO into a first hydrogenation reactor (1008) to obtain LOL; HO is added into a second hydrogenation reactor (1009) to obtain HOH; Adding LOL and HOH into a third hydrogenation reactor (1011), and adding a first rectifying tower (1014) and a second rectifying tower (1015) to carry out fractional rectification after the reaction is finished to respectively obtain cyclohexane, methylcyclohexane and toluene; The first hydrogenation reactor (1008) has the temperature of 240-300 ℃, the reaction pressure of 6-10Mpa, the liquid hourly space velocity of 2-8 h -1 and the hydrogen-oil ratio of 500-1000:1; The carrier of the catalyst is gamma-Al 2 O 3 , and the active substances of the catalyst are Ni, mo and W; The fixed bed is filled with 10-20% of NiMo gamma-Al 2 O 3 at the upper part, 0.8-1.2:0.7-1% of Ni, 10-20% of NiMoW gamma-Al 2 O 3 at the middle part, 0.5-1:0.5-1% of Ni, 10-20% of NiW gamma-Al 2 O 3 at the lower part and 0.5-1:0.5-1% of Ni; The second hydrogenation reactor (1009) has the temperature of 360-420 ℃, the reaction pressure of 15-20Mpa, the liquid hourly space velocity of 0.5-1 h -1 and the hydrogen-oil ratio of 800-1700:1; The carrier of the catalyst is beta molecular sieve and gamma-Al 2 O 3 , and the active substances of the catalyst are Ni, co, mo and W; The fixed bed is filled with NiMo gamma-Al 2 O 3 at the upper part, niMo active ingredient 20-30%, ni 0.8-1.2:0.7-1%, niMoW gamma-Al 2 O 3 at the middle part, niMoW active ingredient 10-20%, ni 0.5-1:0.5-1%, coMo gamma-beta molecular sieve at the lower part, coMo active ingredient 10-20% and Ni 0.5-1:0.5-1; The temperature of the third hydrogenation reactor (1011) is 340-390 ℃, the reaction pressure is 14-18Mpa, the liquid hourly space velocity is 0.8-1.2 h -1 , and the hydrogen-oil ratio is 500-1200:1; The carrier of the catalyst is beta molecular sieve and gamma-Al 2 O 3 , and the active substances of the catalyst are Ni, mo and W; The fixed bed is filled with upper NiMoW gamma-Al 2 O 3 , active components of 20-30%, ni: mo: W0.5-1:0.5-1, middle NiMo gamma-Al 2 O 3 , active components of 20-30%, ni: mo 0.5-1:0.5-1, lower W-beta molecular sieve, and active components of 10-20%.
  2. 2. The method for preparing chemicals by hydrogenating medium and low temperature coal tar according to claim 1, wherein the specific process of adding LO into the first hydrogenation reactor (1008) to obtain LOL is as follows: Fractionating the top of a distillation tower (1001) to obtain a light fraction LO, enabling the LO to enter a first raw material storage tank (1002), adding the LO in the first raw material storage tank (1002) into a first booster pump (1004), mixing with hydrogen, pressurizing, preheating, then entering a first hydrogenation reactor (1008), carrying out demetallization and partial oxygen-containing compound deoxidization on a catalyst in the first hydrogenation reactor (1008), and obtaining the light fraction LOL after the reaction is completed; The sample injection mode is from bottom to top.
  3. 3. The method for preparing chemical by hydrogenating medium and low temperature coal tar according to claim 1, wherein the specific process of adding HO into the second hydrogenation reactor (1009) to obtain HOH is: Fractionating the bottom of a distillation tower (1001) to obtain heavy fraction HO, introducing the HO into a second raw material storage tank (1003), adding the HO in the second raw material storage tank (1003) into a second pressurizing pump (1005), mixing with hydrogen, pressurizing, preheating, introducing into a second hydrogenation reactor (1009), and carrying out hydrocracking reaction on a catalyst in the second hydrogenation reactor (1009) to obtain hydrocracked oil HOH; the sample injection mode is from top to bottom.
  4. 4. The method for preparing chemicals by hydrogenating medium and low temperature coal tar according to claim 1, wherein the concrete process of adding LOL and HOH into the third hydrogenation reactor (1011) is: Pressurizing HOH and LOL and hydrogen by a third pressurizing pump (1010), and then introducing the HOH and LOL and the hydrogen into a third hydrogenation reactor (1011) to respectively perform deoxidation, saturation, cracking and secondary saturation reactions to obtain a fraction LHO; the fraction LHO enters a high-pressure separator (1012) for gas-liquid separation, the gas phase enters a third raw material storage tank (1013) through heat exchange, and the liquid phase is LHOR; the sample injection mode is from top to bottom.
  5. 5. The method for preparing chemicals by hydrogenating medium and low temperature coal tar according to claim 1, wherein the rectification process is specifically as follows: LHOR enters a first rectifying tower (1014) for rectification, cyclohexane is obtained at the top of the first rectifying tower (1014), tower bottom materials of the first rectifying tower (1014) enter a second rectifying tower (1015) for rectification, methylcyclohexane is obtained at the top of the second rectifying tower (1015), and toluene is obtained at the bottom of the second rectifying tower (1015).
  6. 6. A chemical product obtainable by the process according to any one of claims 1 to 5, comprising in particular cyclohexane, methylcyclohexane and toluene.
  7. 7. A process system for the preparation of chemicals according to claim 6, characterized in that it comprises in particular: A distillation column (1001), a first raw material storage tank (1002), a second raw material storage tank (1003), a first pressurizing pump (1004), a second pressurizing pump (1005), a first preheating furnace (1006), a second preheating furnace (1007), a first hydrogenation reactor (1008), a second hydrogenation reactor (1009), a third pressurizing pump (1010), a third hydrogenation reactor (1011), a high-pressure separator (1012), a third raw material storage tank (1013), a first rectifying column (1014), and a second rectifying column (1015); The top outlet of the distillation column (1001) is fixedly connected with a first raw material storage tank (1002), a first booster pump (1004), a first preheating furnace (1006), a first hydrogenation reactor (1008), a third booster pump (1010), a third hydrogenation reactor (1011), a high-pressure separator (1012), a third raw material storage tank (1013), a first rectification column (1014) and a second rectification column (1015) in sequence through pipelines and communicated with each other; The bottom outlet of the distillation tower (1001) is fixedly connected with a second raw material storage tank (1003), a second pressurizing pump (1005), a second preheating furnace (1007), a second hydrogenation reactor (1009), a third pressurizing pump (1010), a third hydrogenation reactor (1011), a high-pressure separator (1012), a third raw material storage tank (1013), a first rectifying tower (1014) and a second rectifying tower (1015) in sequence through pipelines and communicated with each other; The top outlet of the high-pressure separator (1012) is fixedly connected with the third raw material storage tank (1013) through a pipeline and communicated with each other, and the bottom outlet of the high-pressure separator (1012) is fixedly connected with the third pressurizing pump (1010).
  8. 8. A process system for the preparation of chemicals as claimed in claim 7, wherein: The first hydrogenation reactor (1008) is a pre-hydrogenation reactor; the second hydrogenation reactor (1009) is a hydrocracking reactor; the third hydrogenation reactor (1011) is a hydrofining reactor.

Description

Preparation method and process system for preparing chemicals by hydrogenating medium-low temperature coal tar Technical Field The invention relates to the technical field of coal chemical industry, in particular to a preparation method and a process system for preparing chemicals by hydrogenating medium-low temperature coal tar. Background The total output of medium-low temperature coal tar in China is about 800 ten thousand tons, and the production enterprises are mainly distributed in Shaan, xin, mongolian, ning and Gantai/autonomous regions. The medium-low temperature coal tar has multiple components and complex components, and is difficult to separate efficiently. Because the catalyst is rich in aliphatic hydrocarbon, aromatic hydrocarbon and phenolic compounds, the catalyst contains petroleum-like components, and is suitable for preparing fuel oil by hydrogenation. Through the development of more than ten years, the fuel oil prepared by hydrogenating the medium-low temperature coal tar is quite large in local scale, but the grading utilization degree of tar oil is low, and the product is single. In addition, the new energy automobile industry is rapidly developed, is promoted by various aspects of policies, technologies and markets, the market scale is continuously enlarged, and the demand of fuel oil is impacted, so that the catalytic conversion of medium-low temperature coal tar into high-added-value chemicals is an important transformation, and gradually becomes a main utilization way. Chinese invention CN116987523a relates to a method for preparing monocyclic aromatic hydrocarbon and naphtha by using pyrolysis decarbonization of medium-low temperature coal tar. The method comprises the steps of distilling medium-low temperature coal tar under atmospheric and vacuum conditions to cut out fraction section asphalt with the temperature of more than 350 ℃, extracting and refining the cut asphalt by using a solvent to obtain refined asphalt rich in polycyclic aromatic hydrocarbon, compounding the refined asphalt rich in polycyclic aromatic hydrocarbon with a functional solvent to obtain a compound mixed raw material, and carrying out pyrolysis decarbonization on the compound mixed raw material under the hydrogen condition to obtain a product containing monocyclic aromatic hydrocarbon and naphtha. The invention CN106701181B provides a method and a device for preparing monocyclic aromatic hydrocarbon by taking the whole fraction of medium-low temperature coal tar as a raw material, carrying out fractionation, cracking and refining the light phase, cracking the heavy phase twice, and refining the cracked whole fraction of medium-low temperature coal tar. Chinese invention CN108641749B relates to a hydrogenation combined process for producing high quality fuel by using medium and low temperature coal tar, wherein the medium and low temperature coal tar is distilled by a hydro-thermal cracking unit, a first normal pressure fractionation unit, a hydro-refining unit, a vacuum fractionation unit, a diesel oil hydro-upgrading unit, a wax oil hydro-cracking unit, a gasoline and diesel precious metal hydrogenation unit and a fourth normal pressure fractionation unit, so as to obtain the final products of naphtha, aviation kerosene, diesel oil, etc. Chinese invention CN105694970B relates to a method for producing high density jet fuel by hydrogenating medium-low temperature coal tar, mixing and heating medium-low temperature coal tar and hydrogen, obtaining naphtha, crude jet fuel and tail oil after fractionating hydrogenation products, and refining crude jet fuel with clay to obtain high density No. 6 jet fuel with good oxidation stability, good emulsification resistance and good insulation. In summary, the technology for preparing fuel oil based on the hydrogenation of the medium-low temperature coal tar derives the technology for preparing aromatic hydrocarbon, naphthenic oil, space kerosene and the like from the medium-low temperature coal tar, and the hydrogenation product of the medium-low temperature coal tar is expanded. The products obtained by the technology are all mixtures obtained by fractionation and cutting of hydrogenation products, and the fractionation products are further processed to obtain the products of aromatic hydrocarbon, naphthenic base oil, aerospace coal oil and the like. At present, the technology for preparing chemicals from medium-low temperature coal tar is lacking, and the development of the technology can promote the hydrogenation of the medium-low temperature coal tar to develop towards the direction of fine chemicals. Based on the above, the invention designs a preparation method and a process system for preparing chemicals by hydrogenating medium-low temperature coal tar to solve the problems. Disclosure of Invention Aiming at the defects existing in the prior art, the invention provides a preparation method and a process system for preparing chemicals by hydrogenating medium-l