A preparation method of bio-jet fuel based on soapstock hydrogenation

Abstract

The present application relates to the technical fields of bio-jet fuel, and discloses a preparation method of bio-jet fuel based on soapstock hydrogenation, wherein a Ni-Mo-P molecular sieve hydrogenation catalyst is filled into a hydrogenation refining reactor, pretreated soapstock is fed into the hydrogenation refining reactor through a preheater, hydrogen is fed into the hydrogenation refining reactor, hydrogenation deoxidization reaction is carried out, high-condensation HVO / deoxidized oil is obtained, the high-condensation HVO / deoxidized oil is fed into an isomerization condensation reduction reactor, hydrogen is fed into the isomerization condensation reduction reactor, isomerization condensation reduction reaction is carried out, and bio-jet fuel based on soapstock hydrogenation is obtained. The Ni-Mo-P active catalytic sites are uniformly formed in the molecular sieve matrix, the active catalytic sites have high dispersity and are not easy to be agglomerated, the pretreated soapstock fatty acid has higher selective hydrogenation deoxidization catalytic effect, the prepared bio-jet fuel has the advantages of high branched alkane content and low aromatic content, and has excellent combustion performance.

Description

Technical Field

[0001] This invention relates to the field of bio-jet fuel technology, specifically a method for preparing bio-jet fuel based on soapstock hydrogenation. Background Technology

[0002] Bio-jet fuel is typically produced from renewable resources such as waste cooking oil, animal and vegetable oils, and agricultural and forestry waste through a catalyst-assisted process involving hydrodeoxygenation and isomerization-dewaxing reactions. Soap residue, a byproduct of vegetable oil refining, is inexpensive and readily available. It mainly contains fatty acid salts and glycerides, with a high total fatty acid content. After sulfuric acid acidification, the remaining oils and fatty acids from soap residue can be used to produce soap, biodiesel, and bio-jet fuel, achieving waste reuse and offering economic, environmental, and resource benefits.

[0003] Hydrodeoxygenation catalysts for preparing bio-jet fuel are mainly metal catalysts, such as ruthenium, nickel, molybdenum, and tungsten. Typically, these metal catalysts need to be supported on molecular sieves, activated carbon, alumina, or other carriers to achieve high dispersion and better hydrodeoxygenation catalytic efficiency. Patent application CN202511407989.2 discloses a catalyst and its preparation method for one-step hydrogenation of waste oil to biofuel. It reacts nickel, molybdenum, and tungsten sources, HY molecular sieve powder, methylcellulose, and citric acid to obtain a catalyst with hydrodeoxygenation, cracking, and isomerization functions, enabling the one-step conversion of waste oil into bio-jet fuel and biodiesel. However, the bio-jet fuel and biodiesel have a high content of ≤C8 hydrocarbons and aromatics, which affects their combustion performance. Summary of the Invention

[0004] This invention solves the problem of low efficiency of molecular sieve catalysts in the hydrogenation and deoxygenation of soapstock.

[0005] The technical solution of this invention is: a method for preparing bio-jet fuel based on soapstock hydrogenation. (1) Add water and template agent P123 triblock copolymer to the reaction vessel, stir and add hydrochloric acid dropwise, heat to the hydrolysis temperature, add tetraethyl orthosilicate and 1-(tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol, stir to carry out hydrolysis condensation reaction, then pour the solution into a hydrothermal reactor for hydrothermal reaction, cool and filter, wash the precipitate with ethanol and water, dry to obtain tetraazacyclone molecular sieve.

[0006] (2) Add water, tetraazine heterocyclic molecular sieve, nickel nitrate and ammonium molybdate to the container, stir and disperse, add phosphoric acid dropwise, stir and dry to remove water, place in a tube furnace for calcination, cool to obtain Ni-Mo-P molecular sieve hydrogenation catalyst.

[0007] (3) Add ethanol, water, sulfuric acid solution and soap residue to the reaction vessel, heat and stir, remove ethanol by vacuum distillation, add hot water, stir and let stand to separate the layers, remove the water layer, separate and collect the oil layer, remove phospholipids from the oil layer by biological enzymatic degumming with phospholipase A1, then add activated clay to the oil phase, stir and adsorb, filter to remove activated clay, and obtain pretreated soap residue.

[0008] (4) Ni-Mo-P molecular sieve hydrogenation catalyst is loaded into the hydrorefining reactor. The pretreated soap residue is passed into the hydrorefining reactor through a preheater and hydrogen is introduced to carry out the hydrodeoxygenation reaction. The reaction product is passed into a three-phase separator through a condenser for "oil-gas-water" three-phase separation. The oil phase enters the stripping tower for fractionation to remove light components. The bottom oil of the tower is high-pour-point HVO / deoxygenated oil.

[0009] (5) The high-pour-point HVO / deoxygenated oil is introduced into the heterogeneous dewaxing reactor, hydrogen is introduced, and the heterogeneous dewaxing reaction is carried out. The reaction products are successively subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter the distillation column for splitting to obtain bio-jet fuel based on soap foot hydrogenation.

[0010] Preferably, in (1), the hydrolysis temperature is 40-45℃ and the hydrolysis condensation reaction time is 3-5h; the hydrothermal reaction temperature is 100-110℃ and the reaction time is 18-24h.

[0011] Preferably, in (1) the ratio of water, template agent P123 triblock copolymer, hydrochloric acid, tetraethyl orthosilicate, and 1-(tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol is (420-640) mL: (16.8-20.4) g: (84-104) mL: 40 g: (2.8-4.8) g.

[0012] Preferably, in (1) 1-(tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol is 1-(1,4,7,10-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol or 1-(1,4,8,11-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol.

[0013] Preferably, the ratio of tetraazine-heterocyclic molecular sieve, nickel nitrate, ammonium molybdate, and phosphoric acid in (2) is 10g:(3-5.5)g:(3.8-7.2)g:(11.2-12.6)g.

[0014] Preferably, the stirring and dispersion time in (2) is 2-3 hours.

[0015] Preferably, in (2), the calcination is carried out at a heating rate of 5-7℃ / min, from room temperature to 500-550℃, and held for 2-3 hours.

[0016] Preferably, the ratio of ethanol, water, sulfuric acid solution and soap residue in (3) is (240-280)L:(12-18)L:(1.7-2.3)L:(35-40)kg.

[0017] Preferably, the heating and stirring temperature in (3) is 68-70℃.

[0018] Preferably, in the hydrodeoxygenation reaction of (4), the pressure of the hydrorefining reactor is 4-6 MPa, the reaction temperature is 330-380℃, and the liquid hourly space velocity is 1-1.8 h⁻¹. -1 The ratio of hydrogen to hydrogen oil in pretreated soap feet is 1000-1400:1.

[0019] Preferably, in the isomerization dewaxing reaction (5), the pressure in the isomerization dewaxing reactor is 3-5 MPa and the space velocity is 0.6-1.2 h⁻¹. -1 The reaction temperature is 340-380℃, and the hydrogen-to-oil ratio of hydrogen to high-condensation HVO / deoxygenated oil is 800-1000:1.

[0020] The beneficial technical effects of this invention are as follows: This invention involves the hydrolysis and condensation reaction of 1-(tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol containing a triethoxysilane structure with tetrazolium tetrahydric ester to obtain a tetraazacyclocyclone molecular sieve containing tetraazacyclone and hydroxyl groups. This sieve can coordinate with nickel and molybdenum atoms, thereby uniformly adsorbing nickel and molybdenum into the porous matrix of the molecular sieve. During high-temperature calcination, nickel and molybdenum react with phosphoric acid to generate active substances such as nickel-molybdenum-phosphorus complexes, thereby uniformly forming Ni-Mo-P active catalytic sites in the molecular sieve matrix. The active catalytic sites have high dispersion and are not prone to agglomeration, resulting in a higher selective hydrodeoxygenation catalytic effect on pretreated soapstock fatty acids. The prepared bio-jet fuel has the advantages of high branched alkane content and low aromatic content, and excellent combustion performance. Attached Figure Description

[0021] Figure 1 This is a scanning electron microscope image of the Ni-Mo-P molecular sieve hydrogenation catalyst from Example 1. Detailed Implementation

[0022] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. The described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0023] 1-(1,4,7,10-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)propoxy]prop-2-ol (structural formula: ) was prepared according to the method described in the journal article "Synthesis, colloidalstability and 64Cu labeling of iron oxide nanoparticles bearing different macrocyclic ligands" in New J. Chem., 2011, 35, 2705-2712. ) and 1-(1,4,8,11-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)propoxy]prop-2-ol (structural formula: ).

[0024] Ethanol, water, 98% concentrated sulfuric acid solution, and soap residue were added to the reactor in a mass ratio of 280:15:2:37.1. The mixture was heated to 70°C and stirred under reflux until the residual soap content decreased to 0.06%. Ethanol was removed by vacuum distillation. Hot water at 95°C was added, and the mixture was stirred and allowed to stand to separate into layers. The water layer was removed, and the oil layer was separated and collected. Phospholipase A1 (0.1% of the oil layer mass, sourced from Novozymes Biotechnology Co., Ltd.) was used to degumme the oil layer using a bio-enzymatic method to remove phospholipids. Then, 2% of the oil phase mass of activated clay was added to the oil phase, stirred for adsorption, and filtered to remove the activated clay, resulting in pretreated soap residue.

[0025] Example 1:

[0026] (1) Add 540 mL of water and 20.4 g of template agent P123 triblock copolymer (polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, the same below) to the reaction vessel, stir, add 90 mL of 37% hydrochloric acid by mass, heat to 40 °C, add 40 g of tetraethyl orthosilicate and 2.8 g of 1-(1,4,7,10-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol, stir to carry out hydrolysis and polycondensation for 4 h, then pour the solution into a hydrothermal reactor, heat to 100 °C, react for 24 h, cool and filter, wash the precipitate with ethanol and water, dry, and obtain tetraazacyclone molecular sieve.

[0027] (2) Add 120 mL of water, 10 g of tetraazine-based molecular sieve, 3 g of nickel nitrate, and 7.2 g of ammonium molybdate to a container, stir and disperse for 2 h, add 11.7 g of phosphoric acid dropwise, stir for 20 min, dry to remove water, place in a tube furnace, heat from room temperature to 500 °C at a heating rate of 5 °C / min, keep warm and calcine for 3 h, cool, and obtain Ni-Mo-P molecular sieve hydrogenation catalyst. Figure 1 Scanning electron microscopy images show that the molecular sieve hydrogenation catalyst is porous.

[0028] (3) 20g of Ni-Mo-P molecular sieve hydrogenation catalyst was loaded into the hydrorefining reactor. The pretreated soapstock was introduced into the hydrorefining reactor through a preheater, and hydrogen was introduced. The pressure of the hydrorefining reactor was 5MPa, and the hydrogen-to-oil ratio of hydrogen to pretreated soapstock was 1200:1. The hydrodeoxygenation reaction was carried out at 360℃ with a liquid hourly space velocity of 1h. -1 The reaction products are condensed and then enter a three-phase separator for "oil-gas-water" three-phase separation. The oil phase enters a stripping tower for fractionation to remove light components. The bottom oil is high-pour-point HVO / deoxygenated oil.

[0029] (4) The high-pour-point HVO / deoxygenated oil is introduced into the isomerization dewaxing reactor, and hydrogen is introduced. The pressure of the isomerization dewaxing reactor is 4 MPa, and the hydrogen-to-oil ratio of hydrogen to high-pour-point HVO / deoxygenated oil is 900:1. The isomerization dewaxing reaction is carried out at 350℃ with a space velocity of 1 h⁻¹. -1 The reaction products are sequentially subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation.

[0030] Example 2:

[0031] (1) Add 420 mL of water and 16.8 g of template agent P123 triblock copolymer to the reaction vessel, stir and add 104 mL of 37% hydrochloric acid by mass, heat to 45 °C, add 40 g of tetraethyl orthosilicate and 3.6 g of 1-(1,4,7,10-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol, stir and carry out hydrolysis and polycondensation for 3 h, then pour the solution into a hydrothermal reactor, heat to 100 °C, react for 24 h, cool and filter, wash the precipitate with ethanol and water, dry to obtain tetraazacyclone molecular sieve.

[0032] (2) Add 150 mL of water, 10 g of tetraazine-based molecular sieve, 5.5 g of nickel nitrate, and 3.8 g of ammonium molybdate to a container, stir and disperse for 2 h, add 12.6 g of phosphoric acid dropwise, stir for 40 min, dry to remove water, place in a tube furnace, heat from room temperature to 550 °C at a heating rate of 7 °C / min, keep warm and calcine for 2 h, cool to obtain Ni-Mo-P molecular sieve hydrogenation catalyst.

[0033] (3) 20g of Ni-Mo-P molecular sieve hydrogenation catalyst was loaded into the hydrorefining reactor. The pretreated soapstock was introduced into the hydrorefining reactor through a preheater, and hydrogen was introduced. The pressure of the hydrorefining reactor was 4MPa, and the hydrogen-to-oil ratio of hydrogen to pretreated soapstock was 1400:1. The hydrodeoxygenation reaction was carried out at 330℃ with a liquid hourly space velocity of 1.8h. -1 The reaction products are condensed and then enter a three-phase separator for "oil-gas-water" three-phase separation. The oil phase enters a stripping tower for fractionation to remove light components. The bottom oil is high-pour-point HVO / deoxygenated oil.

[0034] (4) The high-pour-point HVO / deoxygenated oil is introduced into the isomerization dewaxing reactor, and hydrogen is introduced. The pressure of the isomerization dewaxing reactor is 6 MPa, and the hydrogen-to-oil ratio of hydrogen to high-pour-point HVO / deoxygenated oil is 800:1. The isomerization dewaxing reaction is carried out at 340℃ with a space velocity of 1 h⁻¹. -1 The reaction products are sequentially subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation.

[0035] Example 3:

[0036] (1) Add 600 mL of water and 16.8 g of template agent P123 triblock copolymer to the reaction vessel, stir and add 92 mL of 37% hydrochloric acid by mass, heat to 40 °C, add 40 g of tetraethyl orthosilicate and 4 g of 1-(1,4,8,11-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol, stir and carry out hydrolysis and polycondensation for 5 h, then pour the solution into a hydrothermal reactor, heat to 100 °C, react for 24 h, cool and filter, wash the precipitate with ethanol and water, dry to obtain tetraazacyclone molecular sieve.

[0037] (2) Add 130 mL of water, 10 g of tetraazine-based molecular sieve, 4.8 g of nickel nitrate, and 5.5 g of ammonium molybdate to a container, stir and disperse for 3 h, add 11.2 g of phosphoric acid dropwise, stir for 20 min, dry to remove water, place in a tube furnace, heat from room temperature to 500 °C at a heating rate of 5 °C / min, keep warm and calcine for 3 h, cool, and obtain Ni-Mo-P molecular sieve hydrogenation catalyst.

[0038] (3) 20g of Ni-Mo-P molecular sieve hydrogenation catalyst was loaded into the hydrorefining reactor. The pretreated soapstock was introduced into the hydrorefining reactor through a preheater, and hydrogen was introduced. The pressure of the hydrorefining reactor was 5MPa, and the hydrogen-to-oil ratio of hydrogen to pretreated soapstock was 1000:1. The hydrodeoxygenation reaction was carried out at 380℃ with a liquid hourly space velocity of 1.5h. -1The reaction products are condensed and then enter a three-phase separator for "oil-gas-water" three-phase separation. The oil phase enters a stripping tower for fractionation to remove light components. The bottom oil is high-pour-point HVO / deoxygenated oil.

[0039] (4) The high-pour-point HVO / deoxygenated oil is introduced into the isomerization dewaxing reactor, and hydrogen is introduced. The pressure of the isomerization dewaxing reactor is 5 MPa, and the hydrogen-to-oil ratio of hydrogen to high-pour-point HVO / deoxygenated oil is 800:1. The isomerization dewaxing reaction is carried out at 350℃ with a space velocity of 1.2 h⁻¹. -1 The reaction products are sequentially subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation.

[0040] Example 4:

[0041] (1) Add 640 mL of water and 16.8 g of template agent P123 triblock copolymer to the reaction vessel, stir and add 84 mL of 37% hydrochloric acid by mass, heat to 40 °C, add 40 g of tetraethyl orthosilicate and 4.8 g of 1-(1,4,8,11-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol, stir and carry out hydrolysis and polycondensation for 5 h, then pour the solution into a hydrothermal reactor, heat to 100 °C, react for 24 h, cool and filter, wash the precipitate with ethanol and water, dry to obtain tetraazacyclone molecular sieve.

[0042] (2) Add 130 mL of water, 10 g of tetraazine-based molecular sieve, 4.2 g of nickel nitrate, and 6.3 g of ammonium molybdate to a container, stir and disperse for 3 h, add 11.2 g of phosphoric acid dropwise, stir for 20 min, dry to remove water, place in a tube furnace, heat from room temperature to 500 °C at a heating rate of 5 °C / min, keep warm and calcine for 3 h, cool, and obtain Ni-Mo-P molecular sieve hydrogenation catalyst.

[0043] (3) 20g of Ni-Mo-P molecular sieve hydrogenation catalyst was loaded into the hydrorefining reactor. The pretreated soapstock was introduced into the hydrorefining reactor through a preheater, and hydrogen was introduced. The pressure of the hydrorefining reactor was 4MPa, and the hydrogen-to-oil ratio of hydrogen to pretreated soapstock was 1200:1. The hydrodeoxygenation reaction was carried out at 350℃ with a liquid hourly space velocity of 1.8h. -1 The reaction products are condensed and then enter a three-phase separator for "oil-gas-water" three-phase separation. The oil phase enters a stripping tower for fractionation to remove light components. The bottom oil is high-pour-point HVO / deoxygenated oil.

[0044] (4) The high-pour-point HVO / deoxygenated oil is introduced into the isomerization dewaxing reactor, and hydrogen is introduced. The pressure of the isomerization dewaxing reactor is 3 MPa, and the hydrogen-to-oil ratio of hydrogen to high-pour-point HVO / deoxygenated oil is 1000:1. The isomerization dewaxing reaction is carried out at 380℃ with a space velocity of 0.6 h⁻¹.-1 The reaction products are sequentially subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation.

[0045] Comparative Example 1 differs from Example 1 in that 1-(1,4,7,10-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)propoxy]prop-2-ol is not added.

[0046] (1) Add 540 mL of water and 20.4 g of template agent P123 triblock copolymer to the reaction vessel, stir and add 90 mL of 37% hydrochloric acid by mass, heat to 40 °C, add 40 g of tetraethyl orthosilicate, stir and carry out hydrolysis and polycondensation for 4 h, then pour the solution into a hydrothermal reactor, heat to 100 °C, react for 24 h, cool and filter, wash the precipitate with ethanol and water, dry and obtain molecular sieve.

[0047] (2) Add 120 mL of water, 10 g of molecular sieve, 3 g of nickel nitrate and 7.2 g of ammonium molybdate to the container, stir and disperse for 2 h, add 11.7 g of phosphoric acid dropwise, stir for 20 min, dry to remove water, place in a tube furnace, heat from room temperature to 500 °C at a heating rate of 5 °C / min, keep warm and calcine for 3 h, cool to obtain Ni-Mo-P molecular sieve hydrogenation catalyst.

[0048] (3) 20g of Ni-Mo-P molecular sieve hydrogenation catalyst was loaded into the hydrorefining reactor. The pretreated soapstock was introduced into the hydrorefining reactor through a preheater, and hydrogen was introduced. The pressure of the hydrorefining reactor was 5MPa, and the hydrogen-to-oil ratio of hydrogen to pretreated soapstock was 1200:1. The hydrodeoxygenation reaction was carried out at 360℃ with a liquid hourly space velocity of 1h. -1 The reaction products are condensed and then enter a three-phase separator for "oil-gas-water" three-phase separation. The oil phase enters a stripping tower for fractionation to remove light components. The bottom oil is high-pour-point HVO / deoxygenated oil.

[0049] (4) The high-pour-point HVO / deoxygenated oil is introduced into the isomerization dewaxing reactor, and hydrogen is introduced. The pressure of the isomerization dewaxing reactor is 4 MPa, and the hydrogen-to-oil ratio of hydrogen to high-pour-point HVO / deoxygenated oil is 900:1. The isomerization dewaxing reaction is carried out at 350℃ with a space velocity of 1 h⁻¹. -1 The reaction products are sequentially subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation.

[0050] Comparative Example 2 differs from Example 1 in that 1,4,7,10-tetraazacyclododecane (CAS No. 294-90-6) is used instead of 1-(1,4,7,10-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)propoxy]prop-2-ol.

[0051] (1) Add 540 mL of water and 20.4 g of template agent P123 triblock copolymer to the reaction vessel, stir and add 90 mL of 37% hydrochloric acid by mass, heat to 40 °C, add 40 g of tetrazolium silicate and 2.8 g of 1,4,7,10-tetraazacyclododecane, stir and carry out hydrolysis and polycondensation for 4 h, then pour the solution into a hydrothermal reactor, heat to 100 °C, react for 24 h, cool and filter, wash the precipitate with ethanol and water, dry and obtain molecular sieve.

[0052] (2) Add 120 mL of water, 10 g of molecular sieve, 3 g of nickel nitrate and 7.2 g of ammonium molybdate to the container, stir and disperse for 2 h, add 11.7 g of phosphoric acid dropwise, stir for 20 min, dry to remove water, place in a tube furnace, heat from room temperature to 500 °C at a heating rate of 5 °C / min, keep warm and calcine for 3 h, cool to obtain Ni-Mo-P molecular sieve hydrogenation catalyst.

[0053] (3) 20g of Ni-Mo-P molecular sieve hydrogenation catalyst was loaded into the hydrorefining reactor. The pretreated soapstock was introduced into the hydrorefining reactor through a preheater, and hydrogen was introduced. The pressure of the hydrorefining reactor was 5MPa, and the hydrogen-to-oil ratio of hydrogen to pretreated soapstock was 1200:1. The hydrodeoxygenation reaction was carried out at 360℃ with a liquid hourly space velocity of 1h. -1 The reaction products are condensed and then enter a three-phase separator for "oil-gas-water" three-phase separation. The oil phase enters a stripping tower for fractionation to remove light components. The bottom oil is high-pour-point HVO / deoxygenated oil.

[0054] (4) The high-pour-point HVO / deoxygenated oil is introduced into the isomerization dewaxing reactor, and hydrogen is introduced. The pressure of the isomerization dewaxing reactor is 4 MPa, and the hydrogen-to-oil ratio of hydrogen to high-pour-point HVO / deoxygenated oil is 900:1. The isomerization dewaxing reaction is carried out at 350℃ with a space velocity of 1 h⁻¹. -1 The reaction products are sequentially subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation.

[0055] Comparative Example 3 differs from Example 1 in that 1-(1,4,7,10-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)propoxy]prop-2-ol is replaced with 3-glycidyl etheroxypropyltriethoxysilane (CAS No. 2602-34-8).

[0056] (1) Add 540 mL of water and 20.4 g of template agent P123 triblock copolymer to the reaction vessel, stir and add 90 mL of 37% hydrochloric acid by mass, heat to 40 °C, add 40 g of tetraethyl orthosilicate and 2.8 g of 3-glycidyl etheroxypropyltriethoxysilane, stir and carry out hydrolysis and polycondensation for 4 h, then pour the solution into a hydrothermal reactor, heat to 100 °C, react for 24 h, cool and filter, wash the precipitate with ethanol and water, dry and obtain epoxy molecular sieve.

[0057] (2) Add 120 mL of water, 10 g of epoxy molecular sieve, 3 g of nickel nitrate and 7.2 g of ammonium molybdate to the container, stir and disperse for 2 h, add 11.7 g of phosphoric acid dropwise, stir for 20 min, dry to remove water, place in a tube furnace, heat from room temperature to 500 °C at a heating rate of 5 °C / min, keep warm and calcine for 3 h, cool to obtain Ni-Mo-P molecular sieve hydrogenation catalyst.

[0058] (3) 20g of Ni-Mo-P molecular sieve hydrogenation catalyst was loaded into the hydrorefining reactor. The pretreated soapstock was introduced into the hydrorefining reactor through a preheater, and hydrogen was introduced. The pressure of the hydrorefining reactor was 5MPa, and the hydrogen-to-oil ratio of hydrogen to pretreated soapstock was 1200:1. The hydrodeoxygenation reaction was carried out at 360℃ with a liquid hourly space velocity of 1h. -1 The reaction products are condensed and then enter a three-phase separator for "oil-gas-water" three-phase separation. The oil phase enters a stripping tower for fractionation to remove light components. The bottom oil is high-pour-point HVO / deoxygenated oil.

[0059] (4) The high-pour-point HVO / deoxygenated oil is introduced into the isomerization dewaxing reactor, and hydrogen is introduced. The pressure of the isomerization dewaxing reactor is 4 MPa, and the hydrogen-to-oil ratio of hydrogen to high-pour-point HVO / deoxygenated oil is 900:1. The isomerization dewaxing reaction is carried out at 350℃ with a space velocity of 1 h⁻¹. -1 The reaction products are sequentially subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation.

[0060] Comparative Example 4 differs from Example 1 in that γ-aminopropyltriethoxysilane (CAS No. 919-30-2) is used instead of 1-(1,4,7,10-tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)propoxy]prop-2-ol.

[0061] (1) Add 540 mL of water and 20.4 g of template agent P123 triblock copolymer to the reaction vessel, stir and add 90 mL of 37% hydrochloric acid by mass, heat to 40 °C, add 40 g of tetraethyl orthosilicate and 2.8 g of γ-aminopropyltriethoxysilane, stir and carry out hydrolysis and polycondensation for 4 h, then pour the solution into a hydrothermal reactor, heat to 100 °C, react for 24 h, cool and filter, wash the precipitate with ethanol and water, dry and obtain amino molecular sieve.

[0062] (2) Add 120 mL of water, 10 g of amino molecular sieve, 3 g of nickel nitrate and 7.2 g of ammonium molybdate to the container, stir and disperse for 2 h, add 11.7 g of phosphoric acid dropwise, stir for 20 min, dry to remove water, place in a tube furnace, heat from room temperature to 500 °C at a heating rate of 5 °C / min, keep warm and calcine for 3 h, cool to obtain Ni-Mo-P molecular sieve hydrogenation catalyst.

[0063] (3) 20g of Ni-Mo-P molecular sieve hydrogenation catalyst was loaded into the hydrorefining reactor. The pretreated soapstock was introduced into the hydrorefining reactor through a preheater, and hydrogen was introduced. The pressure of the hydrorefining reactor was 5MPa, and the hydrogen-to-oil ratio of hydrogen to pretreated soapstock was 1200:1. The hydrodeoxygenation reaction was carried out at 360℃ with a liquid hourly space velocity of 1h. -1 The reaction products are condensed and then enter a three-phase separator for "oil-gas-water" three-phase separation. The oil phase enters a stripping tower for fractionation to remove light components. The bottom oil is high-pour-point HVO / deoxygenated oil.

[0064] (4) The high-pour-point HVO / deoxygenated oil is introduced into the isomerization dewaxing reactor, and hydrogen is introduced. The pressure of the isomerization dewaxing reactor is 4 MPa, and the hydrogen-to-oil ratio of hydrogen to high-pour-point HVO / deoxygenated oil is 900:1. The isomerization dewaxing reaction is carried out at 350℃ with a space velocity of 1 h⁻¹. -1 The reaction products are sequentially subjected to heterogeneous hot high-pressure separation and heterogeneous cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation.

[0065] The composition of bio-jet fuel was tested using the ASTM D2425-21 standard.

[0066] Table 1. Composition of bio-jet fuel Example 1 87.54 6.85 0.47 Example 2 91.78 4.43 0.76 Example 3 85.24 7.82 0.50 Example 4 95.31 3.09 0.58 Comparative Example 1 65.52 3.19 3.56 Comparative Example 2 67.15 3.57 3.50 Comparative Example 3 65.13 3.06 3.87 Comparative Example 4 73.60 5.14 2.21 As shown in Table 1, the Ni-Mo-P molecular sieve hydrogenation catalysts of Examples 1-4 exhibit higher hydrogenation deoxygenation efficiency for pretreated soapstock fatty acids, enabling efficient conversion of oils into bio-jet fuel with high branched-chain alkanes and high cycloalkanes content. This is mainly because the tetraazine heterocyclic molecular sieve contains cyclic tetraazine heterocyclic structures and hydroxyl groups, which can coordinate with nickel and molybdenum atoms, thereby uniformly adsorbing nickel and molybdenum into the porous matrix of the molecular sieve. During high-temperature calcination, nickel and molybdenum react with phosphoric acid to generate active substances such as nickel-molybdenum phosphides, which uniformly form Ni-Mo-P active catalytic sites in the molecular sieve matrix. The active catalytic sites have high dispersion and are not prone to aggregation, resulting in a higher selective hydrogenation deoxygenation catalytic effect for pretreated soapstock fatty acids. The prepared bio-jet fuel has the advantages of high branched-chain alkanes and cycloalkanes content and low aromatic content, exhibiting excellent combustion performance.

[0067] The molecular sieve of Comparative Example 1 does not contain structures such as tetranitrogen heterocycles, making it difficult to form coordination interactions with nickel and molybdenum atoms. As a result, nickel and molybdenum cannot be uniformly adsorbed into the porous matrix of the molecular sieve. The generated Ni-Mo-P active catalytic sites are not uniformly dispersed in the molecular sieve matrix, resulting in fewer active catalytic sites. Consequently, the selective hydrogenation and deoxygenation catalytic effect on soapstock fatty acids is poor, and the content of branched alkanes and cycloalkanes in bio-jet fuel is significantly lower than that in Example 1.

[0068] The 1,4,7,10-tetraazacyclododecane in Comparative Example 2 does not contain a siloxane structure and cannot undergo hydrolysis and condensation reaction with tetraethyl orthosilicate. After washing, 1,4,7,10-tetraazacyclododecane is easily eluted from the molecular sieve, resulting in the molecular sieve not containing tetraaza heterocycles and other structures. The Ni-Mo-P active catalytic sites generated subsequently are not uniformly dispersed in the molecular sieve matrix and are prone to agglomeration. The selective hydrogenation and deoxygenation catalytic effect on soapstock fatty acids is poor, and the content of branched alkanes and cycloalkanes in bio-jet fuel is significantly lower than that in Example 1.

[0069] Comparative Example 3 utilizes 3-glycidyl etheroxypropyltriethoxysilane and tetraethyl orthosilicate for hydrolysis and condensation. The resulting molecular sieve does not contain tetranitrogen heterocycles or similar structures. The subsequently generated Ni-Mo-P active catalytic sites are not uniformly dispersed in the molecular sieve matrix and are prone to agglomeration. The selective hydrogenation and deoxygenation catalytic effect on soapstock fatty acids is poor, and the content of branched alkanes and cycloalkanes in bio-jet fuel is significantly lower than that in Example 1.

[0070] Comparative Example 4 utilizes γ-aminopropyltriethoxysilane and tetraethyl orthosilicate for hydrolysis and condensation. The resulting molecular sieve contains only amino groups and no cyclic tetraazine heterocycles or other structures. Its coordination and adsorption with nickel and molybdenum atoms are weak. The Ni-Mo-P active catalytic sites in the molecular sieve matrix are poorly dispersed, resulting in fewer active catalytic sites than in Example 1. The selective hydrogenation and deoxygenation catalytic effect on soapstock fatty acids is poor, and the content of branched alkanes and cycloalkanes in bio-jet fuel is lower than in Example 1, making it prone to agglomeration.

[0071] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing bio-jet fuel based on soapstock hydrogenation, characterized in that, The preparation method is as follows: S1. Ni-Mo-P molecular sieve hydrogenation catalyst is loaded into the hydrorefining reactor. Pretreated soap residue is passed into the hydrorefining reactor through a preheater and hydrogen is introduced to carry out hydrodeoxygenation reaction. The reaction product is separated by a three-phase separator through a condenser. The oil phase is fractionated in a stripping tower to remove light components. The bottom oil of the tower is high-pour-point HVO / deoxygenated oil. S2. High-pour-point HVO / deoxygenated oil is introduced into an isomerization dewaxing reactor, hydrogen is introduced, and an isomerization dewaxing reaction is carried out. The reaction products are successively subjected to isomerization hot high-pressure separation and isomerization cold high-pressure separation, and then enter a distillation column for splitting to obtain bio-jet fuel based on soapstock hydrogenation. During the hydrodeoxygenation reaction in S1, the pressure in the hydrorefining reactor is 4-6 MPa, the reaction temperature is 330-380℃, and the liquid hourly space velocity is 1-1.8 h⁻¹. -1 The hydrogen-to-oil ratio of hydrogen to pretreated soap feet is 1000-1400:1; During the isomerization dewaxing reaction in S2, the pressure in the isomerization dewaxing reactor is 3-5 MPa, and the space velocity is 0.6-1.2 h⁻¹. -1 The reaction temperature is 340-380℃, and the hydrogen-to-oil ratio of hydrogen to high-condensation HVO / deoxygenated oil is 800-1000:

1. The preparation method of the Ni-Mo-P molecular sieve hydrogenation catalyst is as follows: (1) Add water and template agent P123 triblock copolymer to the reaction vessel, stir and add hydrochloric acid dropwise, heat to the hydrolysis temperature, add tetraethyl orthosilicate and 1-(tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol, stir to carry out hydrolysis condensation reaction, then pour the solution into a hydrothermal reactor for hydrothermal reaction, cool and filter, wash the precipitate, dry to obtain tetraazacyclone molecular sieve; (2) Add water, tetraazine heterocyclic molecular sieve, nickel nitrate and ammonium molybdate to the container, stir and disperse, add phosphoric acid dropwise, stir and dry to remove water, place in a tube furnace for calcination, cool to obtain Ni-Mo-P molecular sieve hydrogenation catalyst; The 1-(tetraazacyclotetradecano-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol is 1-(1,4,7,10-tetraazacyclotetradecano-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol or 1-(1,4,8,11-tetraazacyclotetradecano-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol; The preparation method of the pretreated soapstock is as follows: ethanol, water, sulfuric acid solution and soapstock are added to the reaction vessel, heated and stirred under reflux, ethanol is removed by vacuum distillation, hot water at 90-95℃ is added, stirred and allowed to stand for separation, the water layer is removed, the oil layer is separated and collected, the oil layer is degummed by phospholipase A1 to remove phospholipids, then activated clay is added to the oil phase, stirred and adsorbed, the activated clay is removed by filtration to obtain the pretreated soapstock; the ratio of ethanol, water, sulfuric acid solution and soapstock is (240-280) L: (12-18) L: (1.7-2.3) L: (35-40) kg.

2. The method for preparing bio-jet fuel based on soapstock hydrogenation according to claim 1, characterized in that, In (1), the hydrolysis temperature is 40-45℃ and the hydrolysis condensation reaction time is 3-5h; the hydrothermal reaction temperature is 100-110℃ and the reaction time is 18-24h.

3. The method for preparing bio-jet fuel based on soapstock hydrogenation according to claim 1, characterized in that, The ratio of water, template agent P123 triblock copolymer, hydrochloric acid, tetraethyl orthosilicate, and 1-(tetraazacyclotetradecane-1-yl)-3-[3-(triethoxysilyl)-propoxy]prop-2-ol in (1) is (420-640) mL: (16.8-20.4) g: (84-104) mL: 40 g: (2.8-4.8) g.

4. The method for preparing bio-jet fuel based on soapstock hydrogenation according to claim 1, characterized in that, The ratio of tetrazole heterocyclic molecular sieve, nickel nitrate, ammonium molybdate, and phosphoric acid in (2) is 10g:(3-5.5)g:(3.8-7.2)g:(11.2-12.6)g.

5. The method for preparing bio-jet fuel based on soapstock hydrogenation according to claim 1, characterized in that, The stirring and dispersion time in (2) is 2-3h; calcination is carried out at a heating rate of 5-7℃ / min, from room temperature to 500-550℃, and held for 2-3h.

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