CN116790288B - Method for producing biological aviation kerosene by hydrogenating waste grease - Google Patents

Abstract

The present invention relates to the technical field of bio-oil products, and discloses a method for producing bio-jet fuel by hydrogenation of waste oil and fat, which comprises the following steps: waste oil and fat are mixed with hydrogen and a hydrogenation pretreatment catalyst and then enter a slurry bed hydrogenation reactor for hydrogenation; the tailings obtained by the effluent after hydrogenation through a hydrocyclone are partially circulated to the slurry bed hydrogenation reactor; the liquid product is separated into gas and liquid, the hydrogen-rich gas is purified and recycled, and the liquid product is subjected to solid-liquid separation; the separated liquid product enters a series of hydrogenation refining reactors, a hydrocracking reactor and a post-refining reactor for hydrogenation; the hydrogenation product is subjected to gas-liquid separation, and the liquid product is fractionated to obtain bio-jet fuel. The present invention efficiently completes the hydrogenation conversion of non-ideal components such as oxygen-containing compounds in waste oil and fat through slurry bed hydrogenation pretreatment; obtains high-quality bio-jet fuel fractions through deep supplementary hydrogenation treatment; the raw material adaptability is strong; the product yield is high; and the device operation cycle is long.

Description

A method for producing bio-jet fuel by hydrogenating waste oil

Technical Field

The invention relates to the technical field of bio-oil products, and in particular to a method for producing bio-jet fuel by hydrogenating waste oil.

Background technique

Aviation kerosene has appropriate density, high calorific value, good combustion performance, can burn rapidly, stably, continuously and completely, and has a small combustion area, less carbon deposits and is not easy to coke; it has good low-temperature fluidity and can meet the requirements of oil fluidity in cold and low-temperature areas and high-altitude flight; it has good thermal stability and antioxidant stability and can meet the needs of supersonic high-altitude flight; it has high cleanliness, is free of mechanical impurities, moisture and other harmful substances, has a low sulfur content, especially mercaptan sulfur content, and has little corrosion to machine parts.

Compared with traditional fossil fuels, biojet fuel produced from vegetable oils represented by palm oil and waste oils represented by edible waste oil can reduce carbon emissions by 55% to 92%.

Biodiesel made from waste oil and fat belongs to the recycling of waste energy. In Europe, its usage follows the "double reduction counting principle" compared with conventional biofuels (i.e. if the actual addition amount is 1%, it will be counted as 2% when calculating the addition amount). If biodiesel made from waste oil and fat is added, the addition amount of biodiesel can be reduced through the "double reduction counting principle", thus achieving the coordinated development of economy and environmental protection.

Due to the high viscosity, high oxygen content, unstable combustion and low calorific value of biomass raw materials, they cannot be directly used as a substitute for petroleum fuels. Before use, they need to be treated with hydrodeoxygenation (HDO). The main types of oxygen-containing compounds in biomass raw materials include phenols, furans, ketones, aldehydes and esters. The main oxygen-containing compounds in palm oil and edible waste oil are triglycerides, most of which have carbon chain lengths of C _{14 to 22} , of which C ₁₈ and C ₁₆ account for more than 95% of the total fatty acids.

At present, the production process of the second-generation biodiesel is mainly the fixed-bed hydrogenation process. Waste oil raw materials have the disadvantages of high acid value and excessive content of Fe, Na, Ca metal elements and O, N, P and other elements. They are easily deposited on the active components of the hydrogenation catalyst during the hydrogenation reaction, causing the catalyst to be quickly poisoned; in addition, the presence of long-chain olefins and oxygen-containing compounds will cause the catalyst bed to agglomerate and clog, resulting in a rapid increase in reactor pressure drop and shutdown; in addition, due to the different sources of biomass raw materials and complex compositions, the current fixed-bed hydrogenation process generally has problems such as equipment clogging and corrosion, which puts forward higher requirements on the continuity and long-term stable operation of the hydrodeoxygenation process. The long-term stable operation of the hydrodeoxygenation process is the pain point of the production of bio-jet fuel technology.

The carrier of the supported catalyst has a direct impact on the service life and stability of the catalyst. At present, the most commonly used carrier for hydrodeoxygenation (HDO) catalysts is γ-Al ₂ O ₃ . However, the high oxygen content of bio-oil raw materials will cause a certain amount of water to be generated during the hydrodeoxygenation process. In a certain pressure of water vapor, Al ₂ O ₃ will generate boehmite, causing the catalyst structure to collapse, the specific surface area and pore volume to decrease, the mechanical strength to decrease, and the catalytic activity of the catalyst to decrease. Traditional supported catalysts have great limitations in the hydrogenation pretreatment of waste oils and fats.

At present, the main process used to produce second-generation biodiesel is the fixed-bed hydrogenation process. The catalyst used is mainly a supported transition metal sulfide catalyst, and the catalyst carrier used is mostly alumina, such as the NExBTL process used by Neste Oil Group of Finland (US Patent: 7232935), and the Econfining process jointly developed by UOP of the United States and Ente Nazionale Idrocarburi of Italy (US Patent: 20060264684). The domestic production process is basically similar to the above two processes.

Patent application number CN201110373951.X discloses a method for producing biodiesel, which uses waste cooking oil and mineral diesel as raw materials. Although the addition of mineral diesel solves the problem of the effect of H ₂ O generated during hydrodeoxygenation on the service life of the catalyst to a certain extent, the addition of mineral diesel makes the finished biodiesel produced fail to meet the national definition of biodiesel, cannot enjoy corresponding tax benefits, and loses economic benefits.

The patent with application number CN202110261877.6 discloses a process for directly producing jet fuel using waste oil. The process includes pretreatment of crude oil, hydrolysis of high-carbon hydrocarbons to obtain fatty acids, and hydrogenation refining. The operation process is cumbersome, and the operation of hydrolysis to obtain fatty acids increases construction costs and operating costs.

Patent application number CN200610083300.6 discloses a method for preparing biodiesel, which includes an ester exchange reaction between a bio-oil raw material and a short-chain alcohol, and the recovery of methanol and glycerol. The product prepared by this method is a first-generation biodiesel, which has the disadvantages of high energy consumption and difficulty in recovering methyl ester products. The catalyst used in the ester exchange process is a Bronsted acid ion liquid catalyst, which has a high production cost.

Patent application number CN201110192761.8 discloses a method for preparing biodiesel by hydrogenation. The method uses high-quality vegetable oil as raw material and mainly includes processes such as hydrorefining and hydrodecondensation. The catalyst used is a sulfurized catalyst, and sulfur-containing compounds (such as carbon disulfide, sulfide and its derivatives, etc.) need to be used to pre-sulfurize the oxidized catalyst active components. The operation process is complicated and the water pollution is relatively serious. The catalyst carrier used is γ-Al ₂ O ₃ , which will cause the catalyst structure to collapse under long-term hydrothermal conditions, reduce the specific surface area and pore volume, and reduce the mechanical strength.

Patent application number CN201910190312.6 discloses a method for preparing biodiesel, which includes the steps of hydrolysis of glycerol esters, aqueous phase reforming of glycerol to generate hydrogen, and hydrofining. This method does not require the additional introduction of high-purity nitrogen and has low energy consumption. However, the excessively high temperature of the subsequent hydrogenation reaction will inhibit the aqueous phase reforming reaction of glycerol to generate hydrogen, and the product separation is complicated.

Patent application number CN201911163276.6 discloses a method for preparing hydrogenated biodiesel by catalytic directional hydrodeoxygenation of oils and fats. The method uses waste oils and fats as raw materials. The catalyst used is a molecular sieve-supported catalyst Ni ₂ P/SAPO-11. The presence of phosphides will cause a large amount of phosphating wastewater, which has high treatment costs and the wastewater produced is seriously polluting the environment.

Patent application number CN201510263141.7 discloses a method for producing aviation biofuel from waste animal and vegetable oils, which consists of a pretreatment unit, a hydroprocessing unit, a degassing and dehydration unit, a hydroconversion unit, and a distillation unit. The processing procedures are complicated, and a protective agent needs to be loaded in the hydroprocessing unit, and a special catalyst grading process needs to be adopted to prevent the H ₂ O generated during the oil hydrogenation process from affecting the catalyst activity. The operational flexibility is low.

In summary, the above method usually encounters the following problems in the process of using waste oil to produce bio-jet fuel: on the one hand, the composition of waste oil is complex, and the waste oil raw material has the disadvantages of high acid value, high content of Fe, Na, Ca metal elements and elements such as O, N, P, etc., and the fixed bed catalyst is easily poisoned and inactivated, and coking and clogging make it difficult to achieve long-term operation, which brings obstacles to the industrialization of fixed bed hydrodeoxygenation. On the other hand, the carrier of the supported catalyst has a direct impact on the service life and stability of the catalyst. However, the high oxygen content of bio-oil raw materials will cause a certain amount of water to be generated during the hydrodeoxygenation process. In a certain pressure of water vapor _{, Al2O3} will generate boehmite, causing the catalyst structure to collapse, the specific surface area and pore volume to decrease, the mechanical strength to decrease, and the catalytic activity of the catalyst to decrease. Traditional supported catalysts have great limitations in the hydrogenation pretreatment of waste oil. Therefore, eliminating the various defects of the fixed bed in the hydrodeoxygenation process and developing a treatment process that has strong adaptability to raw materials and can achieve large-scale and long-term operation of the device are important issues that need to be solved in this field.

Summary of the invention

In order to solve the deficiencies in the prior art, the present invention provides a method for producing bio-jet fuel by hydrogenating waste oil, and the technical scheme is as follows:

A method for producing bio-jet fuel by hydrogenating waste oils and fats, comprising the following steps:

S101: the waste oil and fat from which mechanical impurities have been removed are fully mixed with hydrogen and a hydrogenation pretreatment catalyst and then enter a slurry bed hydrogenation reactor for hydrogenation pretreatment;

S102: The tailings obtained by the hydrocyclone separator after hydrogenation are partially recycled to the inlet of the slurry bed hydrogenation reactor, and a small amount of tailings are discharged;

S103: The liquid product obtained by separation in the cyclone separator enters the gas-liquid separator for gas-liquid separation, the obtained hydrogen-rich gas is recycled after purification, and the obtained liquid product enters the solid-liquid separator;

S104: the liquid phase product separated by the solid-liquid separator is used as the product after hydrogenation pretreatment, and the solid residue is discharged from the device;

S105: the product after hydrogenation pretreatment enters a fixed bed hydrotreating reactor, a fixed bed hydrocracking reactor and a fixed bed post-treating reactor connected in series for hydrogenation treatment;

S106: The hydrogenation product enters a gas-liquid separation unit for gas-liquid separation, and the obtained liquid product enters a fractionation unit to obtain a naphtha fraction, a bio-jet fuel fraction, and a biodiesel fraction.

Furthermore, in S101, the waste oil, hydrogen and hydrogenation pretreatment catalyst are mixed and enter the slurry bed hydrogenation reactor from the bottom, flowing from bottom to top; the reaction conditions of the slurry bed hydrogenation reactor are: the hydrogen partial pressure in the reactor is 4-20 MPa, the reaction temperature is 340-410°C, the liquid hourly volume space velocity is 0.5-1.5h ^-1 , and the volume ratio of hydrogen to waste oil is 300-1200Nm ³ /m ³ ; the axial temperature distribution of the slurry bed hydrogenation reactor is uniform, and the maximum temperature difference does not exceed 15°C.

Furthermore, the amount of the hydrogenation pretreatment catalyst added in S101 accounts for 0.005-0.2% of the weight of the waste oil.

Furthermore, the operating conditions of the hydrocyclone separator in S102 are: pressure of 4-20 MPa and temperature of 200-300°C; the tailings obtained by the hydrocyclone separator in S102, the amount of which is circulated to the inlet of the slurry bed hydrogenation reactor accounts for 80-99% by weight of the total amount of tailings, and the amount discharged accounts for 1-20% by weight of the total amount of tailings.

Further, the reaction conditions of the fixed bed hydrotreating reactor in S105 are: a hydrogen partial pressure of 4 to 20 MPa in the reactor, a reaction temperature of 280 to 380°C, a liquid hourly volume space velocity of 0.5 to 4 h ^-1 , and a volume ratio of hydrogen to the material entering the reactor of 300 to 1000 Nm ³ /m ³ ; the reaction conditions of the fixed bed hydrocracking reactor in S105 are: a hydrogen partial pressure of 4 to 20 MPa in the reactor, a reaction temperature of 340 to 390°C, a liquid hourly volume space velocity of 0.5 to 4 h ^-1 , and a volume ratio of hydrogen to the material entering the reactor of 300 to 1000 Nm ³ /m ³ ; the reaction conditions of the fixed bed post-refining reactor in S105 are: a hydrogen partial pressure of 4 to 20 MPa in the reactor, a reaction temperature of 240 to 320°C, a liquid hourly volume space velocity of 0.5 to 4 h ^-1 , the volume ratio of hydrogen to the material entering the reactor is 300-1000 Nm ³ /m ³ .

Furthermore, the hydrogenation pretreatment catalyst in S101 is a Group VIB metal Mo or W and a Group VIB metal Co or Ni supported on a carrier, and the catalyst active components account for 10% to 30% by weight of the oxide.

Furthermore, the hydrogenation pretreatment catalyst in S101 is composed of 1 to 6 weight percent nickel oxide and/or cobalt oxide, 6 to 24 weight percent molybdenum oxide and/or tungsten oxide, and the rest being a carbon carrier.

Furthermore, the steps for preparing the hydrogenation pretreatment catalyst in S101 are as follows:

(1) A soluble salt of an active metal is prepared into a solution of a desired concentration, the solution is impregnated into a carbon carrier by an equal volume impregnation method, and the solution is dried at 80 to 200° C. for 1 to 10 hours to obtain an activated carbon-supported metal catalyst; the soluble salt of the active metal includes nickel salts, cobalt salts, molybdenum salts and tungsten salts; the nickel salts include nickel nitrate and basic nickel carbonate; the cobalt salts include cobalt nitrate, cobalt acetate and basic cobalt carbonate; the molybdenum salts include molybdenum oxide and ammonium molybdate; and the tungsten salts include tungsten oxide and ammonium metatungstate;

(2) The activated carbon-supported metal catalyst and the sulfiding agent obtained in step (1) are added to a reactor for hydrothermal treatment, wherein the molar ratio of the sulfur content of the sulfiding agent to the amount of the active metal is 3 to 5:1, and the amount of the active metal is the sum of nickel and/or cobalt and molybdenum and/or tungsten. The reaction temperature is 80 to 200° C. and the reaction time is 2 to 6 hours, thereby obtaining an activated carbon-supported transition metal sulfide catalyst.

Furthermore, the hydrogenation pretreatment catalyst is in a granular form with an outer diameter of 50 to 500 μm; the sulfiding agent is one or more of ammonium sulfide, ammonium polysulfide, elemental sulfur, thiourea, and ammonium thiosulfate.

Furthermore, the waste oil includes one or more of acidified oil, edible waste oil, animal visceral oil, condensate oil from range hoods, clay refined desorption oil, sludge produced during oil pressing, cowhide oil, palmitic acid oil, coconut oil, and palm oil.

Compared with the prior art, the present invention mainly has the following beneficial technical effects:

1. The slurry bed hydrogenation pretreatment process can efficiently realize the hydrogenation and deoxygenation of waste oils and fats, as well as the deep removal of chlorine, metals, phospholipids and other heteroatoms contained therein, and complete the hydrogenation conversion of non-ideal components such as oxygen-containing compounds in waste oils and fats. Among them, the deoxygenation rate of waste oils and fats after slurry bed hydrogenation pretreatment is higher than 99%.

2. Use a hydrotreating reactor, a hydroisomerization reactor and a post-refining reactor in series to achieve deep hydrogenation treatment of waste oils and fats, thereby obtaining high-quality bio-jet fuel fractions.

3. The process is simple.

4. Flexible operation.

5. The raw materials have strong adaptability.

6. The yield of bio-jet fuel products is high.

7. The operation cycle of waste oil hydroprocessing equipment can be significantly extended.

8. It provides technical support for the high added value utilization of waste oil and fat, and has a very broad application prospect.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 is a process flow chart of producing bio-jet fuel by hydrogenation of waste oils and fats according to the present invention;

In the figure: 1-waste oil, 2-hydrogen, 3-hydrogenation pretreatment catalyst, 4-slurry bed hydrogenation reactor, 5-hydrogenation pretreatment reaction product, 6-hydrocyclone separator, 7-hydrocyclone separation solid tailings, 8-hydrocyclone separation liquid product, 9-gas-liquid separator, 10-hydrogen-rich gas, 11-solid-liquid separator, 12-hydrogenation pretreatment product, 13-solid tailings, 14-fixed bed hydrorefining reactor, 15-fixed bed hydrocracking reactor, 16-fixed bed post-refining reactor, 17-gas-liquid separation unit, 18-fractionation unit.

Detailed ways

The method provided by the present invention is further described below in conjunction with the accompanying drawings. Many devices, such as pumps, heat exchangers, compressors, etc., are omitted in the drawings, but are well known to those skilled in the art.

As shown in FIG1 , the detailed process of the method for producing bio-jet fuel by hydrogenation of waste oils and fats according to the present invention is described as follows:

The waste oil 1 from the pipeline is fully mixed with hydrogen 2 and a hydrogenation pretreatment catalyst 3 and then enters a slurry bed hydrogenation reactor 4 for hydrogenation pretreatment. The reaction conditions are: a hydrogen partial pressure of 4-20 MPa in the reactor, a reaction temperature of 340-410°C, a liquid hourly space velocity of 0.5-1.5 h ^-1 , and a volume ratio of hydrogen to waste oil of 300-1200 Nm ³ /m ³ ; the slurry bed hydrogenation pretreatment reaction product 5 is separated by a hydrocyclone 6 to obtain a hydrocyclone solid-containing tailing 7, part of which is circulated to the inlet of the slurry bed hydrogenation reactor 6, and the rest is discharged; the hydrocyclone liquid product 8 obtained by the hydrocyclone 6 enters a gas-liquid separator 9 for gas-liquid separation, the obtained hydrogen-rich gas 10 is recycled after purification, and the liquid product enters a solid-liquid separator 11; the liquid product separated by the solid-liquid separator 11 is a hydrogenation pretreatment product 12, and the solid tailing 13 is discharged from the device. The product 12 after hydrogenation pretreatment enters a fixed-bed hydrofining reactor 14, a fixed-bed hydrocracking reactor 15 and a fixed-bed post-fining reactor 16 connected in series for hydrogenation reaction, wherein the reaction conditions of the fixed-bed hydrofining reactor 14 are: a hydrogen partial pressure of 4-20 MPa in the reactor, a reaction temperature of 280-380°C, a liquid hourly volume space velocity of 0.5-4 h ^-1 , and a volume ratio of hydrogen to the material entering the reactor of 300-1000 Nm ³ /m ³ ; the reaction conditions of the fixed-bed hydrocracking reactor are: a hydrogen partial pressure of 4-20 MPa in the reactor, a reaction temperature of 340-390°C, a liquid hourly volume space velocity of 0.5-4 h ^-1 , and a volume ratio of hydrogen to the material entering the reactor of 300-1000 Nm ³ /m ³ The reaction conditions of the post-fixed bed refining reactor are: hydrogen partial pressure in the reactor is 4-20 MPa, reaction temperature is 240-320°C, liquid hourly space velocity is 0.5-4h ^-1 , and the volume ratio of hydrogen to the material entering the reactor is 300-1000 Nm ³ /m ³ . The hydrogenation product enters the gas-liquid separation unit 17 for gas-liquid separation, and the obtained liquid product enters the fractionation unit 18 to finally obtain high-quality bio-jet fuel fraction.

The properties of the raw materials used in the examples are shown in Table 1.

Table 1 Main properties of waste oil raw materials

Example 1

The preparation method of the hydrogenation catalyst in the process of waste oil hydrogenation pretreatment is adopted: 28.8g of ammonium molybdate tetrahydrate is weighed and dispersed in 120ml of deionized water to obtain a clear solution A; 13.4g of nickel nitrate hexahydrate is weighed and dissolved in 30ml of ammonia water to obtain a clear solution B; the clear solution A and the clear solution B are mixed to form an impregnation solution C; 100g of the carbon support is placed in the impregnation solution C by an equal volume impregnation method, and after impregnation for 60 minutes, it is dried at 120°C for 120 minutes; the dried catalyst is added to a reactor and hydrothermally treated in a thiourea solution, the molar ratio of the sulfur content of the thiourea to the active metal content (the sum of nickel and molybdenum) is 4:1, the reaction temperature is 160°C, and the reaction time is 120 minutes, and the NiMo sulfurized catalyst supported on activated carbon can be obtained. The metal loading of the catalyst is calculated by the mass fraction of MoO ₃ and NiO, wherein: MoO ₃ is 22.0 wt% and NiO is 3.0wt%. The catalyst particle size is 100 μm. The reaction conditions of the slurry bed hydrogenation reactor are shown in Table 2, and the reaction results of the slurry bed hydrogenation reactor are shown in Table 3.

Example 2

The preparation method of the hydrogenation catalyst in the waste oil hydrogenation pretreatment process is adopted: 30.5g of ammonium tungstate hexahydrate is weighed and dispersed in 120ml of deionized water to obtain a clear solution A; 13.6g of nickel nitrate hexahydrate is weighed and dissolved in 30ml of ammonia water to obtain a clear solution B; the clear solution A and the clear solution B are mixed to form an impregnation solution C; 10g of acid-treated activated carbon material is placed in the impregnation solution C by an equal volume impregnation method, and after impregnation for 180 minutes, it is dried at 130°C for 180 minutes, and the dried catalyst is added to a reactor, and hydrothermally treated in a thiourea solution, the molar ratio of the sulfur content of thiourea to the active metal content (the sum of nickel and tungsten) is 4:1, the reaction temperature is 160°C, and the reaction time is 120 minutes, and the NiW sulfided catalyst supported on activated carbon can be obtained. The metal loading of the catalyst is calculated by the mass fraction of WO ₃ and NiO, wherein: WO ₃ is 22.0wt% and NiO is 3.0wt%. The catalyst particle size is 100 μm. The reaction conditions of the slurry bed hydrogenation reactor are shown in Table 2, and the reaction results of the slurry bed hydrogenation reactor are shown in Table 3.

Example 3

The hydrogenation catalyst used is the waste catalyst of industrial diesel hydrorefining catalyst, and its composition is: 72% by weight of aluminum oxide, 4% by weight of nickel oxide, and 24% by weight of molybdenum oxide. The catalyst particle size is 100 μm. The reaction conditions of the slurry bed hydrogenation reactor are shown in Table 2, and the reaction results of the slurry bed hydrogenation reactor are shown in Table 3.

Example 4

This example uses the oil-soluble molybdenum catalyst FGL-202 developed by the State Key Laboratory of Heavy Oil. The reaction conditions of the slurry bed hydrogenation reactor are shown in Table 2, and the reaction results of the slurry bed hydrogenation reactor are shown in Table 3.

Example 5

The liquid product obtained in the above Example 1 is sequentially fed into a fixed-bed hydrotreating reactor, a fixed-bed hydrocracking reactor and a fixed-bed post-refining reactor, wherein the hydrotreating catalyst, the hydrocracking catalyst and the post-refining catalyst can be selected from common commercial catalysts in this field. This embodiment uses the hydrotreating catalyst FGB-302, the hydrocracking catalyst FGB-602 and the post-refining catalyst FGB-502 developed by the State Key Laboratory of Heavy Oil. The reaction conditions of the fixed-bed hydrofining reactor are: the hydrogen partial pressure in the reactor is 8 MPa, the reaction temperature is 340°C, the liquid hourly volume space velocity is 2 h ^-1 , and the hydrogen volume ratio is 600 Nm ³ / m ³ ; the reaction conditions of the fixed-bed hydrocracking reactor are: the hydrogen partial pressure in the reactor is 8 MPa, the reaction temperature is 380°C, the liquid hourly volume space velocity is 1.5 h ^-1 , and the hydrogen volume ratio is 600 Nm ³ / m ³ ; the reaction conditions of the fixed-bed post-fining reactor are: the hydrogen partial pressure in the reactor is 8 MPa, the reaction temperature is 280°C, the liquid hourly volume space velocity is 3 h ^-1 , and the hydrogen volume ratio is 600 Nm ³ / m ³ . The reaction results of the whole process are shown in Table 4.

Table 2 Reaction conditions of waste oil slurry bed hydrogenation pretreatment

Table 3 Reaction results of waste oil slurry bed hydrogenation pretreatment

Table 4 The whole process reaction results of waste oil hydrogenation to produce bio-jet fuel

It can be seen from the results in Table 3 that the waste grease is treated according to the slurry bed hydrogenation process adopted in the method of the present invention. The oxygen content of the hydrogenation pretreatment product obtained by the industrial waste diesel hydrorefining catalyst adopted in Example 3 is 1.52%, and the oxygen content of the hydrogenation pretreatment products of the catalysts adopted in the other embodiments is less than 1%, and the deoxygenation rate reaches more than 90%, among which the deoxygenation rate of the oil-soluble molybdenum-based catalyst and the carbon-supported NiMo catalyst is as high as more than 99%, which realizes the efficient conversion of non-ideal components in the waste grease and meets the requirements of the subsequent further hydrogenation treatment for raw materials.

As shown in Table 4, waste oil is treated according to the method of the present invention to obtain high-quality bio-jet fuel fraction and biodiesel fraction. Therefore, the method of producing bio-jet fuel by hydrogenating waste oil of the present invention has the advantages of simple process flow, high oil liquid yield, good bio-jet fuel quality, etc., and can realize the resource utilization of all fractions of waste oil.

For ordinary technicians in this field, the specific embodiments are only illustrative descriptions of the present invention. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concepts and technical solutions of the present invention, or the concepts and technical solutions of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims (2)

1. The method for producing the biological aviation kerosene by hydrogenating the waste grease is characterized by comprising the following steps of:

s101: fully mixing the waste grease with the mechanical impurities removed, hydrogen and a hydrogenation pretreatment catalyst, and then entering a slurry bed hydrogenation reactor for hydrogenation pretreatment;

S102: recycling a part of tailings obtained by the effluent after hydrogenation through a hydrocyclone to an inlet of a slurry bed hydrogenation reactor, and discharging a small amount of tailings;

s103: the liquid product obtained by separation of the cyclone liquid separator enters a gas-liquid separator for gas-liquid separation, the obtained hydrogen-rich gas is purified and recycled, and the obtained liquid product enters a solid-liquid separator;

s104: taking the liquid phase product separated by the solid-liquid separator as a product after hydrogenation pretreatment, and discharging the solid residue out of the device;

s105: the product after the hydrogenation pretreatment enters a fixed bed hydrofining reactor, a fixed bed hydrocracking reactor and a fixed bed post-refining reactor which are sequentially connected in series for hydrogenation treatment;

S106: the hydrogenation product enters a gas-liquid separation unit to carry out gas-liquid separation, and the obtained liquid product enters a fractionation unit to obtain naphtha fraction, biological aviation kerosene fraction and biodiesel fraction;

The waste grease, hydrogen and the hydrogenation pretreatment catalyst in the S101 are mixed and then enter a slurry bed hydrogenation reactor from the bottom, and flow from bottom to top; the reaction conditions of the slurry bed hydrogenation reactor are as follows: the hydrogen partial pressure in the reactor is 4-20 MPa, the reaction temperature is 340-410 ℃, the liquid hourly space velocity is 0.5-1.5 h ^-1, and the volume ratio of hydrogen to waste grease is 300-1200 Nm ³/m³; the axial temperature of the slurry bed hydrogenation reactor is uniformly distributed, and the maximum temperature difference is not more than 15 ℃;

The adding amount of the hydrogenation pretreatment catalyst in the S101 accounts for 0.005-0.2% of the weight of the waste grease;

The operation conditions of the hydrocyclone in S102 are as follows: the pressure is 4-20 MPa, and the temperature is 200-300 ℃; the tailings obtained by the hydrocyclone in the S102 are recycled to the inlet of the slurry bed hydrogenation reactor, the amount of the tailings is 80-99 wt% of the total amount of the tailings, and the external discharge amount is 1-20 wt% of the total amount of the tailings;

The reaction conditions of the fixed bed hydrofining reactor in the step S105 are as follows: the hydrogen partial pressure in the reactor is 4-20 MPa, the reaction temperature is 280-380 ℃, the liquid hourly space velocity is 0.5-4 h ^-1, and the volume ratio of hydrogen to the material entering the reactor is 300-1000 Nm ³/m³; the reaction conditions of the fixed bed hydrocracking reactor in S105 are as follows: the hydrogen partial pressure in the reactor is 4-20 MPa, the reaction temperature is 340-390 ℃, the liquid hourly space velocity is 0.5-4 h ^-1, and the volume ratio of hydrogen to the material entering the reactor is 300-1000 Nm ³/m³; the reaction conditions of the fixed bed post-refining reactor in S105 are as follows: the hydrogen partial pressure in the reactor is 4-20 MPa, the reaction temperature is 240-320 ℃, the liquid hourly space velocity is 0.5-4 h ^-1, and the volume ratio of hydrogen to the material entering the reactor is 300-1000 Nm ³/m³;

the hydrogenation pretreatment catalyst in S101 is a VIB group metal Mo or W and a VIII group metal Co or Ni which are loaded on a carrier, and the weight of the active components of the catalyst is 10-30% of that of the oxides;

The composition of the hydrogenation pretreatment catalyst in the S101 is as follows: 1 to 6 weight percent of nickel oxide and/or cobalt oxide, 6 to 24 weight percent of molybdenum oxide and/or tungsten oxide, and the balance of carbon carrier;

The preparation steps of the hydrogenation pretreatment catalyst in the step S101 are as follows:

(1) Preparing a solution with a required concentration from soluble salt of active metal, impregnating a carbon carrier by adopting an isovolumetric impregnation method, and drying for 1-10 hours at 80-200 ℃ to obtain an active carbon supported metal catalyst; the active metal soluble salt comprises nickel salt, cobalt salt, molybdenum salt and tungsten salt, wherein the nickel salt comprises nickel nitrate and basic nickel carbonate, the cobalt salt comprises cobalt nitrate, cobalt acetate and basic cobalt carbonate, the molybdenum salt is ammonium molybdate, and the tungsten salt is ammonium metatungstate;

(2) Adding the active carbon supported metal catalyst obtained in the step (1) and a vulcanizing agent into a reaction kettle for hydrothermal treatment, wherein the molar ratio of the sulfur content of the vulcanizing agent to the active metal content is 3-5:1, the active metal content is the sum of nickel and/or cobalt and molybdenum and/or tungsten, the reaction temperature is 80-200 ℃, and the reaction time is 2-6 hours, so that the active carbon supported transition metal sulfide catalyst can be obtained;

The hydrogenation pretreatment catalyst is granular, and the outer diameter is 50-500 mu m; the vulcanizing agent is one or more of ammonium sulfide, ammonium polysulfide, elemental sulfur, thiourea and ammonium thiosulfate.

2. The method for producing biological aviation kerosene by hydrogenating waste oil and fat according to claim 1, wherein the waste oil and fat comprises one or more of acidified oil, animal internal dirty oil, condensate oil of a smoke exhaust ventilator, clay refining desorption oil, fatlute generated in the oil pressing process, beef tallow oil, palmitoylated oil, coconut oil and palm oil.