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CN-118663317-B - C9+ heavy aromatic hydrocarbon lightening catalyst and preparation method and application thereof

CN118663317BCN 118663317 BCN118663317 BCN 118663317BCN-118663317-B

Abstract

The invention discloses a C9+ heavy aromatic hydrocarbon lightening catalyst and a preparation method and application thereof. The catalyst takes a modified ZSM-5 molecular sieve and a modified Beta molecular sieve as acid cracking components, takes VIB group and/or VIII group metals as hydrogenation components, the ratio (A in /A out ) of the acid quantity in the micropore duct of the catalyst to the acid quantity outside the micropore duct is not lower than 100, preferably 200-500, and the ratio (V micro /V meso ) of the micropore volume to the mesoporous volume is 1.0-5.0, preferably 1.5-3.5. The method comprises the modification process of the ZSM-5 molecular sieve and the Beta molecular sieve, and the kneading molding process. The catalyst has both the dealkylation activity of long side chain alkylbenzene and the transalkylation activity of toluene/trimethylbenzene, realizes the light weight of heavy aromatic hydrocarbon without adding toluene, effectively avoids the side reactions such as trimethylbenzene disproportionation, aromatic hydrocarbon condensation and the like, delays carbon deposition and improves the operation period of the device.

Inventors

  • ZHANG XUEHUI
  • HAO WENYUE
  • LIU CHANG
  • GUO JUNHUI
  • WANG FENGLAI
  • PENG SHAOZHONG
  • CAO JUNFENG

Assignees

  • 中国石油化工股份有限公司
  • 中石化（大连）石油化工研究院有限公司

Dates

Publication Date
20260505
Application Date
20230314

Claims (15)

  1. 1. A C9+ heavy aromatic hydrocarbon lightening catalyst is characterized in that the catalyst takes a modified ZSM-5 molecular sieve and a modified Beta molecular sieve as acid cracking components, takes VIB group and/or VIII group metals as hydrogenation components, the content of the modified ZSM-5 molecular sieve is 20% -50% based on the weight of the catalyst, the content of the modified Beta molecular sieve is 30% -70%, the content of the hydrogenation components is 3% -15% based on oxides, the ratio A in /A out of the acid quantity in micropore channels of the catalyst to the acid quantity outside the micropore channels is not lower than 100, and the ratio V micro /V meso of micropore to mesoporous volume is 1.0-5.0; The preparation method of the C9+ heavy aromatic hydrocarbon light catalyst comprises a modification process of the ZSM-5 molecular sieve and the Beta molecular sieve, and a kneading molding process, wherein the modification process comprises the following steps of: (1) Carrying out inorganic acid treatment on ZSM-5 molecular sieve or Beta molecular sieve raw powder; (2) Impregnating the material obtained in the step (1) with a pore canal protection liquid; (3) Treating the material obtained in the step (2) by adopting high-steric hindrance organic acid; (4) Mixing the material obtained in the step (3) with a dealumination silicon-supplementing reagent to dealuminate and supplement silicon; (5) Filtering, washing, drying and roasting the material obtained in the step (4) to obtain a modified ZSM-5 molecular sieve or a modified Beta molecular sieve; In the step (2), the pore canal protecting liquid is one or more of isopropylamine solution, tetraethylammonium hydroxide solution and tetrapropylammonium hydroxide solution; The difference between the total acid amount obtained by pyridine infrared and the micropore pore canal acid amount A out obtained by 2, 6-di-tert-butylpyridine infrared is A in .
  2. 2. The catalyst according to claim 1, wherein the content of the modified ZSM-5 molecular sieve is 20% -30%, the content of the modified Beta molecular sieve is 50% -60%, the content of the hydrogenation component in terms of oxide is 5% -12%, the ratio A in /A out -500 of the acid amount in the micropore channels to the acid amount outside the micropore channels of the catalyst is 1.5-3.5, and the ratio V micro /V meso of the micropore volume to the mesopore volume is based on the weight of the catalyst.
  3. 3. The catalyst according to claim 1, wherein the group VIB metal is molybdenum and/or tungsten, the group VIII metal is cobalt and/or nickel, the weight of the catalyst is 5-15 wt% of the group VIB metal in terms of oxide, and the weight of the group VIII metal in terms of oxide is 3-5 wt%.
  4. 4. A preparation method of the C9+ heavy aromatic hydrocarbon light catalyst according to any one of claims 1-3 is characterized by comprising a modification process of a ZSM-5 molecular sieve and a Beta molecular sieve, and a kneading molding process, wherein the modification process comprises the following steps: (1) Carrying out inorganic acid treatment on ZSM-5 molecular sieve or Beta molecular sieve raw powder; (2) Impregnating the material obtained in the step (1) with a pore canal protection liquid; (3) Treating the material obtained in the step (2) by adopting high-steric hindrance organic acid; (4) Mixing the material obtained in the step (3) with a dealumination silicon-supplementing reagent to dealuminate and supplement silicon; (5) Filtering, washing, drying and roasting the material obtained in the step (4) to obtain a modified ZSM-5 molecular sieve or a modified Beta molecular sieve; in the step (2), the pore canal protecting liquid is one or more of isopropylamine solution, tetraethylammonium hydroxide solution and tetrapropylammonium hydroxide solution.
  5. 5. The method of claim 4, wherein the ZSM-5 molecular sieve has a SiO 2 /Al 2 O 3 molar ratio of 30-100 and the Beta molecular sieve has a SiO 2 /Al 2 O 3 molar ratio of 20-40.
  6. 6. The method according to claim 4, wherein in the step (1), the inorganic acid treatment is carried out by mixing and stirring the ZSM-5 molecular sieve or Beta molecular sieve obtained in the step (1) with an inorganic acid solution, treating at 40-80 ℃ for 0.5-3 hours, and then separating solid from liquid.
  7. 7. A process according to claim 4, wherein the highly sterically hindered organic acid is 2, 4-dimethylbenzenesulfonic acid and/or 2, 5-dimethylbenzoic acid.
  8. 8. The method of claim 4, wherein in the step (3), the material obtained in the step (2) is mixed with water, the liquid-solid volume ratio of the water to the material obtained in the step (2) is 2:1-6:1, and then the organic acid with high steric hindrance is added until the pH value of the solution is reduced to below 8.
  9. 9. The method of claim 4, wherein in step (3), the high steric hindrance organic acid is added until the pH of the solution is reduced to 6.5-7.5.
  10. 10. The method according to claim 4, wherein in the step (4), the dealumination and silicon supplementing agent is at least one of ammonium hexafluorosilicate solution and ethyl orthosilicate solution.
  11. 11. The method of claim 4, wherein the specific operation process of the step (4) is that the material obtained in the step (3) is quickly heated to 60-100 ℃, and is continuously stirred, the dealumination and silicon-supplementing reagent is dropwise added, and the stirring is continuously carried out for 60-120 min after the dropwise addition is finished.
  12. 12. The method according to claim 4, wherein the drying temperature in the step (5) is 100-150 ℃, the drying time is 2-4 hours, the roasting temperature is 400-600 ℃, and the roasting time is 3-5 hours.
  13. 13. The method of claim 4, wherein the kneading and molding process comprises kneading, extruding, molding, drying and roasting the modified ZSM-5 molecular sieve, the modified Beta molecular sieve, the hydrogenation component and the binder to obtain the C9+ heavy aromatic hydrocarbon light catalyst.
  14. 14. The use of a c9+ heavy aromatics lightening catalyst according to any one of claims 1 to 3, wherein the c9+ heavy aromatics are c9+ reformed heavy aromatics.
  15. 15. The use according to claim 14, wherein the c9+ reformed heavy aromatic hydrocarbon has a trimethylbenzene mass content of 30% -50%, a propylbenzene mass content of 3% -10%, a methyl ethylbenzene mass content of 20% -30% and a c10+ aromatic hydrocarbon mass content of 10% -20%.

Description

C9+ heavy aromatic hydrocarbon lightening catalyst and preparation method and application thereof Technical Field Along with the large-scale of the aromatic hydrocarbon combination device in China, the yield of C9+ heavy aromatic hydrocarbon is greatly improved. C9+ heavy aromatics are usually used as gasoline blending components, the selling price is low, fuel tax is required to be paid, the enterprise benefit is seriously influenced, and along with the limitation of the aromatic hydrocarbon content in the automotive gasoline, the C9+ reforming heavy aromatics which can be digested in a gasoline pool are less and less. Meanwhile, in the next few decades, the consumption of BTX is continuously increasing, the profit margin is higher, the technology can utilize the existing hydrocracking device to process and reform heavy aromatic hydrocarbon to obtain BTX, the economic benefit of a refinery can be remarkably improved, the yield of BTX is effectively increased, and technical support is provided for oil conversion. The C9+ heavy aromatic hydrocarbon used as a byproduct of a device for preparing ethylene by catalytic reforming and steam cracking mainly comprises propylbenzene, methyl ethylbenzene, trimethylbenzene and a small amount of C10 aromatic hydrocarbon. In the conversion process of C9+ heavy aromatic hydrocarbon, dealkylation, alkyl transfer of trimethylbenzene and light aromatic hydrocarbon to obtain dimethylbenzene, disproportionation of trimethylbenzene to obtain dimethylbenzene, and simultaneous reactions of formation of tetramethylbenzene, isomerization reaction, aromatic ring saturation, ring opening and condensation carbon deposition are mainly carried out, wherein dealkylation and alkyl transfer are ideal reactions for producing BTX by C9+ heavy aromatic hydrocarbon, other reactions are non-ideal reactions, and how to strengthen ideal reactions and reduce non-ideal reactions is a key for realizing maximum production of BTX by C9+ heavy aromatic hydrocarbon. Patent CN 99113580 uses nickel and bismuth modified zeolite Beta as catalyst, toluene, C9 aromatic hydrocarbon, C10 aromatic hydrocarbon mixture as raw material, wherein the c10+ aromatic hydrocarbon content is 5%, total conversion rate is 47%, and benzene and xylene selectivity is 88%. CN201310512218.0 discloses a catalyst for lightening heavy aromatic hydrocarbon, which comprises, by weight, 30-60% of a mixture of mfi-type zeolite and ZSM-12 molecular sieve, 38.5-69.8% of at least one metal selected from γ -alumina, η -alumina or pseudo-boehmite as a binder, 0.1-0.5% of at least one metal selected from Pt, pd or Ir and 0.1-1% of at least one metal selected from Zn, la, ce or Bi. The catalyst for lightening heavy aromatic hydrocarbon disclosed in the prior art has the problems of more side reactions such as additional toluene, toluene disproportionation, aromatic hydrocarbon condensation and the like. Disclosure of Invention Aiming at the defects of the prior art, the invention provides a C9+ heavy aromatic hydrocarbon lightening catalyst, and a preparation method and application thereof. The catalyst has both long side chain alkylbenzene dealkylation activity and toluene/trimethylbenzene alkyl transfer activity, realizes the light weight of heavy aromatic hydrocarbon without adding toluene, effectively avoids side reactions such as trimethylbenzene disproportionation, aromatic hydrocarbon condensation and the like, delays carbon deposition and improves the operation period of the device. The catalyst takes a modified ZSM-5 molecular sieve and a modified Beta molecular sieve as acid cracking components, takes a metal of a VIB group and/or a metal of a VIII group as a hydrogenation component, and takes the weight of the catalyst as a reference, wherein the content of the modified ZSM-5 molecular sieve is 20% -50%, preferably 20% -30%, the content of the modified Beta molecular sieve is 30% -70%, preferably 50% -60%, the content of the hydrogenation component calculated by oxide is 3% -15%, preferably 5% -12%, the ratio (A in/Aout) of the acid quantity in micropore channels to the acid quantity outside the micropore channels of the catalyst is not lower than 100, preferably 200% -500, and the ratio (V micro/Vmeso) of the micropore volume to the mesoporous volume is 1.0-5.0, preferably 1.5-3.5. In the catalyst, the VIB group metal is molybdenum and/or tungsten, the VIII group metal is cobalt and/or nickel, the weight of the catalyst is taken as a reference, the content of the VIB group metal in terms of oxide is 5-20wt%, and the content of the VIII group metal in terms of oxide is 2-5wt%. The preparation method of the C9+ heavy aromatic hydrocarbon light catalyst comprises a modification process of the ZSM-5 molecular sieve and the Beta molecular sieve, and a kneading molding process, wherein the modification process comprises the following steps of: (1) Carrying out inorganic acid treatment on ZSM-5 molecular sieve or Beta molecular sieve raw