A combined hydrogenation process for producing bioaviation fuels

Abstract

This invention discloses a combined hydrogenation process for producing bio-aviation fuel, comprising the following steps: (1) bio-oil enters the hydrogenation treatment reaction zone for hydrogenation reaction, and the reaction products are separated to obtain a first naphtha fraction, middle distillate oil, and a first tail oil; (2) coal tar enters the hydrogenation pre-refining reaction zone for hydrogenation reaction, and the reaction products are separated to obtain a second naphtha fraction, jet fuel fraction, diesel fraction, and a second tail oil; (3) the first tail oil and the second tail oil enter the hydrorefining reaction zone for hydrogenation reaction, and the hydrorefined product oil obtained after the reaction is separated together with the reaction products obtained from the hydrorefining reaction zone; (4) the middle distillate oil obtained in step (1) and the jet fuel fraction obtained in step (2) enter the isomerization dewaxing reaction zone for reaction, and the reaction products are separated to obtain naphtha and bio-aviation fuel. The bio-aviation fuel produced by the combined hydrogenation process can meet the requirements of GB 6537-2018 "No. 3 Jet Fuel" standard.

Description

Technical Field

[0001] This invention relates to the field of biofuel technology, and in particular to a hydrogenation process for producing biofuel for aviation. Background Technology

[0002] Currently, the aviation industry accounts for approximately 3% of global carbon dioxide emissions. Without emission reduction measures, it is projected that by 2050, global aviation carbon emissions could reach 25% of global carbon emissions. To address the issue of carbon emission reduction in the aviation industry, the development and use of sustainable aviation fuel (SAF) technology has become a research hotspot. SAF is a liquid aviation fuel made from renewable resources or waste. Currently, 11 production process technologies have been certified by ASTM, with the oleo-fat hydrotreating (HEFA) technology being the most widely used. However, bio-aviation fuels produced using the "hydrodeoxygenation-isomerization" oleo-fat hydrotreating technology are mainly composed of alkanes, resulting in low density. This fails to meet the requirements of the GB6537-2018 "No. 3 Jet Fuel" standard, limiting its use to blending components and severely hindering large-scale deployment. Furthermore, oleo-fat hydrotreating processes generally suffer from short operating cycles, rapid catalyst deactivation, and low SAF yields.

[0003] my country faces a shortage of petroleum resources but abundant coal resources, making the development of coal-to-oil substitution technologies crucial for ensuring the country's energy security. Coal tar is a byproduct of coal coking, dry distillation, or gasification processes, and is classified into low-temperature, medium-temperature, and high-temperature coal tar. Due to the high content of aromatics and cycloalkanes in coal tar, coal tar diesel produced using hydrogenation processes has a low cetane number and high polycyclic aromatic hydrocarbon content, while coal tar jet fuel has a low smoke point and high density. To improve product quality, more stringent hydrogenation upgrading processes must be employed, which results in high energy consumption, high carbon emission intensity, and reduced product yield.

[0004] If bio-oil resources can be organically combined with coal tar resources to produce bio-aviation fuel that directly meets the requirements of GB6537-2018 "No. 3 Jet Fuel" standard, it will not only realize the high-value utilization of coal tar resources and reduce the dependence on petroleum resources, but also effectively reduce the carbon emission intensity of the aviation industry and explore a new path for independent emission reduction in my country's aviation industry.

[0005] CN102504866A discloses a method for preparing biodiesel by hydrogenating a mixture of waste cooking oil and mineral diesel, including pretreatment of waste cooking oil; a first-stage hydrogenation process; a second-stage hydrogenation process; and a product fractionation process. Using waste cooking oil and mineral diesel fractions as raw materials, this method prepares high-quality biodiesel and biojet fuel components with low polycyclic aromatic hydrocarbon content, high cetane number, low sulfur, and low nitrogen content. It effectively solves the problems of metal and colloid sedimentation clogging the catalyst bed during the hydrogenation process of animal and vegetable oils, the impact of H2O, CO2, and CO generated in the reaction on catalyst activity, the need for sulfur replenishment in the hydrogenation system, and the impact of concentrated heat release on catalyst lifespan. This method enables continuous and industrialized hydrogenation of animal and vegetable oils, and has practical significance.

[0006] CN11197897A discloses a method for producing aviation kerosene from a mixture of biomass oil and coal tar, belonging to the field of kerosene production. The method involves combining biomass oil and coal tar, and after hydrogenation and reforming the mixed feedstock, obtaining aviation kerosene with a density of 0.78-0.83 g / cm³. 3 The smoke point is also within the range required for aviation kerosene. In particular, the branched alkanes generated after hydrogenation of biomass oil and the cycloalkanes generated after saturation of aromatics in coal tar are ideal components for aviation kerosene, forming aviation kerosene with a low freezing point and high calorific value. This solves the problem that neither of them can meet the fuel standards for aviation kerosene after hydrogenation alone. This invention provides a processing method to increase the added value of low-value medium- and low-temperature coal tar. Coal tar resources are abundant and easy to obtain. Coal tar hydrogenation can replace scarce cycloalkanes oil resources, while promoting the rational utilization of coal tar resources.

[0007] The above technologies simply mix bio-oils with coal tar or mineral oil and then perform conventional hydrogenation. Although they can produce qualified No. 3 jet fuel, they cannot effectively solve the problems of low yield and selectivity of aviation kerosene products and low utilization of bio-carbon sources. Summary of the Invention

[0008] To address the problems existing in the prior art, the present invention provides a combined hydrogenation process for producing bio-aviation fuel. The bio-aviation fuel produced by the combined hydrogenation process not only meets the requirements of GB 6537-2018 "No. 3 Jet Fuel" standard, but also retains the maximum amount of bio-carbon source in the bio-aviation fuel, while improving the yield and selectivity of the bio-aviation fuel.

[0009] This invention provides a combined hydrogenation process for producing biofuel, comprising the following steps:

[0010] (1) In the presence of hydrogen, bio-oil enters the hydrogenation reaction zone for hydrogenation reaction, and the reaction products are separated to obtain the first naphtha fraction, middle distillate oil and the first tail oil.

[0011] (2) In the presence of hydrogen, coal tar enters the hydrogenation pre-refining reaction zone for hydrogenation reaction. The reaction products are separated to obtain the second naphtha fraction, jet fuel fraction, diesel fraction, and second tail oil.

[0012] (3) In the presence of hydrogen, the first tail oil and the second tail oil enter the hydrotreating reaction zone for hydrotreating reaction. After the reaction, the hydrotreating generated oil is separated from the reaction product obtained in the hydrotreating pre-refining reaction zone in step (2).

[0013] (4) In the presence of hydrogen, the intermediate distillate oil obtained in step (1) and the aviation kerosene fraction obtained in step (2) enter the isomerization dewaxing reaction zone to react, and the reaction products are separated to obtain naphtha and bio-aviation fuel.

[0014] Furthermore, as some specific implementation methods, the bio-oil mentioned in step (1) can be one or more of vegetable oil, animal oil, and waste oil; the vegetable oil can be selected from at least one of soybean oil, rapeseed oil, palm oil, cottonseed oil, and jatropha oil; the animal oil can generally be at least one of lard, tallow, mutton fat, and fish oil; and the waste oil generally comes from at least one of acidified oil, kitchen waste oil, gutter oil, and swill oil.

[0015] Furthermore, as some specific implementation methods, the bio-oil mentioned in step (1) has a water content of no more than 300 ppm and no obvious mechanical impurities. Before entering the reactor, it can be pretreated by dehydration and impurity removal. There are no special restrictions on the dehydration and impurity removal pretreatment method, and any suitable method can be used.

[0016] Furthermore, as some specific implementation methods, the hydrogenation treatment reaction zone in step (1) is filled with a hydrogenation refining catalyst, preferably also including a hydrogenation protection catalyst. The hydrogenation protection catalyst and the hydrogenation refining catalyst are sequentially filled according to the liquid phase material flow direction. More specifically, the volume ratio of the hydrogenation protection catalyst to the hydrogenation refining catalyst is 1:20 to 1:2. The hydrogenation protection catalyst and the hydrogenation refining catalyst can be prepared according to methods disclosed in the art, or commercially available products can be selected. Furthermore, the hydrogenation protection catalyst can be any one or more combinations of the FZC series hydrogenation protection catalysts developed by Sinopec (Dalian) Petrochemical Research Institute, specifically at least one of FZC-103, FZC-105, FZC-106, and FZC-204 catalysts. The hydrorefining catalyst can be any one or a combination of the FHUDS series hydrorefining catalysts, FF series hydrotreating catalysts, and FZC series hydrotreating catalysts developed by Sinopec (Dalian) Petrochemical Research Institute, specifically at least one of the FHUDS-5, FHUDS-6, FF-32, FF-66, and FZC-41 catalysts.

[0017] Furthermore, as some specific implementation methods, the process conditions of the hydrogenation reaction zone described in step (1) are as follows: reaction temperature is 180℃~380℃, preferably 240℃~320℃, hydrogen partial pressure is 1.0MPa~10.0MPa, preferably 3.0~8.0MPa, and volume hourly space velocity is 0.1h. -1 ~4.0h -1 Preferably 0.4h -1 ~2.0h -1 The hydrogen-to-oil volume ratio is 100:1 to 3000:1, preferably 600:1 to 1500:1.

[0018] Furthermore, as some specific implementation methods, the cutting temperature between the first naphtha fraction and the middle distillate oil in step (1) is 100℃~120℃; the cutting temperature between the middle distillate oil and the first tail oil is 320℃~340℃.

[0019] Furthermore, as some specific implementation methods, the hydrogenation treatment reaction zone in step (1) is generally equipped with at least one hydrogenation reactor, which can be selected from at least one of a fixed-bed hydrogenation reactor, a fluidized-bed hydrogenation reactor, and a suspended-bed hydrogenation reactor, with a fixed-bed hydrogenation reactor being preferred.

[0020] Furthermore, as some specific implementation methods, the coal tar mentioned in step (2) can be selected from one or more of low-temperature coal tar, medium-temperature coal tar, and high-temperature coal tar. Furthermore, the coal tar is preferentially subjected to dehydration and removal of mechanical impurities; the dehydrated coal tar raw material has a water content of no more than 300 ppm and no obvious mechanical impurities.

[0021] Furthermore, as some specific implementation methods, the hydrogenation pre-refining reaction zone in step (2) is filled with a hydrogenation refining catalyst, preferably also including a hydrogenation protection catalyst. The hydrogenation protection catalyst and the hydrogenation refining catalyst are sequentially filled according to the direction of liquid phase material flow. More specifically, the volume ratio of the hydrogenation protection catalyst to the hydrogenation refining catalyst is 1:20 to 1:6. The hydrogenation protection catalyst and the hydrogenation refining catalyst can be prepared according to methods disclosed in the art, or commercially available products can be selected. Furthermore, the hydrogenation protection catalyst can be any one or more combinations of the FHMJ series coal tar-specific hydrogenation protection catalysts developed by Sinopec (Dalian) Petrochemical Research Institute, specifically at least one of the following catalysts: FHMJ-F1, FHMJ-F2, FHMJ-B3, FHMJ-B5, and FHMJ-B6. The hydrorefining catalyst can be any one or a combination of the FHMJ series of coal tar-specific hydrorefining catalysts developed by Sinopec (Dalian) Petrochemical Research Institute, specifically at least one of the FHMJ-21, FHMJ-22, and FHMJ-6 catalysts.

[0022] Furthermore, as some specific implementation methods, the process conditions of the hydrogenation pre-purification reaction zone in step (2) are as follows: reaction temperature is 220℃~420℃, preferably 260℃~380℃, hydrogen partial pressure is 5.0MPa~20.0MPa, preferably 8.0~16.0MPa, and volume hourly space velocity is 0.1h. -1 ~6.0h -1 Preferably 0.5h -1 ~2.5h -1 The hydrogen-to-oil volume ratio is 100:1 to 2000:1, preferably 400:1 to 1000:1.

[0023] Furthermore, as some specific implementation methods, the final boiling point of the second naphtha fraction in step (2) is generally controlled at 140℃~180℃; the final boiling point of the jet fuel fraction is generally controlled at 220℃~260℃; and the final boiling point of the diesel fraction is generally controlled at 340℃~380℃.

[0024] Furthermore, as some specific implementation methods, the second naphtha fraction in step (2) is recycled back to the hydrotreating reaction zone for processing together with bio-oils.

[0025] Furthermore, as some specific implementation methods, the hydrogenation pre-purification reaction zone in step (2) is generally equipped with at least one hydrogenation reactor, which can be selected from at least one of a fixed-bed hydrogenation reactor, a fluidized-bed hydrogenation reactor, and a suspended-bed hydrogenation reactor, with a fixed-bed hydrogenation reactor being preferred.

[0026] Furthermore, as some specific implementation methods, the process conditions of the hydrotreating reaction zone in step (3) are as follows: reaction temperature is 180℃~450℃, preferably 270℃~380℃, hydrogen partial pressure is 5.0MPa~20.0MPa, preferably 8.0~16.0MPa, and volume hourly space velocity is 0.1h. -1 ~6.0h -1 Preferably 0.5h -1 ~3.0h -1 The hydrogen-to-oil volume ratio is 100:1 to 3000:1, preferably 600:1 to 1200:1.

[0027] Furthermore, as some specific implementation methods, in step (3), the hydrotreating reaction zone is sequentially filled with a hydrotreating protection catalyst, a hydrorefining catalyst, and a hydrotreating catalyst according to the direction of liquid phase material flow; wherein, the total volume ratio of the hydrorefining catalyst and the hydrotreating catalyst to the volume ratio of the hydrotreating protection catalyst is 10:1 to 10:3, and the volume ratio of the hydrorefining catalyst to the hydrotreating catalyst is 1:9 to 9:1. The hydrotreating protection catalyst, the hydrorefining catalyst, and the hydrotreating catalyst can be prepared according to methods disclosed in the art, or commercially available products can be selected. Furthermore, the hydrotreating protection catalyst can be any one or more combinations of the FZC series hydrotreating protection catalysts developed by Sinopec (Dalian) Petrochemical Research Institute, specifically at least one of the FZC-103, FZC-105, FZC-106, and FZC-204 catalysts. The hydrorefining catalyst can be any one or more combinations of the FF series hydrotreating catalysts developed by Sinopec (Dalian) Petrochemical Research Institute, specifically at least one of FF-26, FF-36, FF-46, FF-56, and FF-66 catalysts. The hydroreforming catalyst can be any one or more combinations of the FC series hydrocracking catalysts developed by Sinopec (Dalian) Petrochemical Research Institute, specifically at least one of FC-14, FC-16, FC-28, and FC-80 catalysts.

[0028] Furthermore, as some specific implementation methods, the hydrogenation reaction zone in step (3) is generally equipped with at least one hydrogenation reactor, which can be selected from at least one of a fixed-bed hydrogenation reactor, a fluidized-bed hydrogenation reactor, and a suspended-bed hydrogenation reactor, with a fixed-bed hydrogenation reactor being preferred.

[0029] Furthermore, as some specific implementation methods, the mass ratio of the intermediate distillate oil obtained in step (1) to the jet fuel distillate obtained in step (2) is 4:1 to 99:1, preferably 6:1 to 19:1.

[0030] Furthermore, as some specific implementation methods, the isomeric pour point depressing reaction zone described in step (4) is filled with an isomeric pour point depressing catalyst. The isomeric pour point depressing catalyst can also be prepared according to the methods disclosed in the art, or commercially available products can be selected. For example, any one or more combinations of the FIW series of isomeric pour point depressing catalysts developed by Sinopec (Dalian) Petrochemical Research Institute can be selected, specifically at least one of FIW-1, FIW-12, FIW-12U, FIW-12D, and FIW-20 catalysts.

[0031] Furthermore, as some specific implementation methods, the process conditions of the isomerization decondensation reaction zone described in step (4) are as follows: reaction temperature is 180℃~420℃, preferably 240℃~350℃, hydrogen partial pressure is 0.05MPa~30MPa, preferably 2.0~15.0MPa, and volume hourly space velocity is 0.1h. -1 ~6.0h -1 Preferably 0.5h -1 ~4.0h -1 The hydrogen-to-oil volume ratio is 100:1 to 3000:1, preferably 500:1 to 1500:1.

[0032] Furthermore, as some specific implementation methods, the final boiling point of the naphtha described in step (4) can generally be controlled to be 120℃~140℃.

[0033] Furthermore, as some specific implementation methods, the heterogeneous dewaxing reaction zone in step (4) is generally equipped with at least one hydrogenation reactor, which can be selected from at least one of a fixed-bed hydrogenation reactor, a fluidized-bed hydrogenation reactor, and a suspended-bed hydrogenation reactor, with a fixed-bed hydrogenation reactor being preferred.

[0034] Furthermore, as some specific implementation methods, the hydrogen in the combined hydrogenation process can be hydrogen obtained after purification / refining of raw coal gas, a by-product of coal dry distillation.

[0035] Furthermore, as some specific implementation methods, the separation in steps (1), (2) and (4) generally includes gas-liquid separation and / or fractionation. The reaction products are first subjected to gas-liquid separation, and the separated liquid phase material is further fed into a fractionation tower for further separation. The specific separation operation method and conditions can be selected according to actual needs.

[0036] Compared with existing processes, the combined hydrogenation process for producing bio-aviation fuel provided by this invention has one or more of the following advantages:

[0037] (1) In the combined hydrogenation process for producing bio-aviation fuel provided by the present invention, the middle distillate oil rich in n-alkane is mixed with the refined coal tar jet fuel fraction rich in aromatics and subjected to isomerization dewaxing treatment. There is a certain competitive adsorption between aromatics and n-alkane. Aromatic molecules will preferentially adsorb on the strong acid sites on the surface of the isomerization dewaxing catalyst. This can greatly reduce the probability of cracking side reactions of n-alkane. It is equivalent to enhancing the selectivity of isomerization reaction of n-alkane on the medium-strong acid sites with isomerization activity. While ensuring the dewaxing effect, it achieves the maximum retention of bio-carbon source in bio-aviation fuel and greatly improves the yield of target product.

[0038] (2) In the combined hydrogenation process for producing bio-aviation fuel provided by this invention, the first tail oil is blended into the second tail oil, which increases the potential content of alkane in the feedstock entering the hydrotreating reaction zone. Under relatively mild reaction conditions, the cetane number of the obtained coal tar diesel fraction can be significantly increased. This not only realizes the high-value utilization of the first tail oil, but also improves the quality of the coal tar hydrogenated product and reduces the carbon emission intensity of the product. At the same time, it avoids the problem that the first tail oil contains polycyclic cycloalkane compounds and a large amount of undesorbed metal impurities, which would increase the density of the bio-aviation fuel and affect the product quality.

[0039] (3) In the combined hydrogenation process for producing bio-aviation fuel provided by this invention, the second naphtha fraction obtained after hydrogenation of coal tar feedstock is used as the circulating oil for bio-oils. This not only serves the same purpose of diluting the feedstock and reducing the heat of reaction, but also, because the second naphtha fraction obtained after hydrogenation of refined coal tar is rich in cycloalkanes and aromatics, it can effectively prevent the stratification of bio-oils during the hydrogenation process, thereby improving the hydrogenation conversion efficiency of the oils. In addition, the second naphtha fraction after pre-hydrogenation and refining retains a certain sulfur content, which can supplement hydrogen sulfide for the hydrogenation reaction of bio-oils and prevent catalyst deactivation due to sulfur loss. At the same time, the catalyst in the pre-hydrogenation and refining reaction zone has limited saturation capacity for aromatics, and the second naphtha fraction used as the circulating oil still retains a high aromatic potential content, making it a high-quality reforming feedstock.

[0040] (4) In the combined hydrogenation process for producing bio-aviation fuel provided by the present invention, the abundant hydrogen produced as a by-product during coal dry distillation can be used to make up for the lack of hydrogen source when building a separate bio-oil hydrogenation unit. By utilizing the similarity between the pretreatment processes of bio-oil and coal tar, and the complementarity of the group composition of bio-oil and coal tar, the organic coupling of the coal tar hydrogenation process and the bio-oil hydrogenation process significantly reduces the construction cost and operating cost of the unit. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the combined hydrogenation process for producing bio-aviation fuel according to the present invention. Detailed Implementation

[0042] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments. The following embodiments will further illustrate the method provided by the present invention, but do not limit the scope of the invention.

[0043] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0044] The description of exemplary embodiments is intended to be read in conjunction with the accompanying drawings, which are considered an integral part of the entire written description. In this specification, relative terms such as “lower,” “upper,” “horizontal,” “vertical,” “above,” “below,” “upward,” “downward,” “top,” and “bottom,” and their derivatives (e.g., “horizontally,” “downward,” “upward,” etc.) should be interpreted as referring to the orientation shown in the accompanying drawings as described at the time. These relative terms are for ease of description and do not require the device to be constructed or operated in a particular orientation. Unless otherwise stated, “connection” as used in this invention refers to a relationship in which structures are directly or indirectly fixed or connected to each other via an intermediate structure.

[0045] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0046] In this document, all numeric values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numeric value.

[0047] like Figure 1As shown, the specific process of the combined hydrogenation process for producing bio-aviation fuel provided by this invention is as follows: Bio-oil 1 enters the hydrogenation treatment reaction zone and undergoes a hydrogenation reaction in the presence of hydrogen 16, contacting the hydrogenation protection catalyst and the hydrogenation refining catalyst packed therein. The reaction product 2 enters the first separation unit and is separated to obtain the first naphtha fraction 3, the middle distillate oil 4, and the first tail oil 5; Coal tar 9 enters the hydrogenation pre-refining reaction zone and undergoes a hydrogenation reaction in the presence of hydrogen 16, contacting the hydrogenation protection catalyst and the hydrogenation refining catalyst packed therein. The reaction product 10 enters the second separation unit. After separation in the first separation unit, the following fractions are obtained: second naphtha fraction 11, jet fuel fraction 12, diesel fraction 13, and second tail oil 14. The second naphtha fraction 11 can be recycled back to the hydrotreating reaction zone to undergo hydrotreating together with the bio-oil 1. The first tail oil 5 and the second tail oil 14 enter the hydrotreating reaction zone, where they undergo a hydrotreating reaction in the presence of hydrogen 16, contacting the hydrotreating protection catalyst, hydrorefining catalyst, and hydrotreating catalyst. The resulting hydrotreating product oil 15 enters the second separation unit and undergoes separation together with the reaction product 10 obtained from the hydrotreating pre-refining reaction zone. The middle distillate oil 4 obtained from the first separation unit and the jet fuel fraction 12 enter the isomerization dewaxing reaction zone, where they react in the presence of hydrogen 16, contacting the isomerization dewaxing catalyst. The reaction product 6 enters the third separation unit and, after separation, yields naphtha 7 and bio-aviation fuel 8.

[0048] In this paper, the bio-oil raw materials used include kitchen waste oil and palm oil, and the coal tar raw materials include medium-temperature coal tar and low-temperature coal tar. The specific properties are shown in Table 1.

[0049] Table 1 Properties of Crude Oil

[0050]

[0051]

[0052] In this paper, the hydrogenation protection catalyst used in the hydrogenation reaction zone is FZC-204 catalyst, and the hydrogenation refining catalyst is FF-36 catalyst.

[0053] In this paper, the hydrogenation protection catalyst used in the hydrogenation pre-purification reaction zone is the FHMJ-B6 catalyst, and the hydrogenation purification catalyst is the FHMJ-22 catalyst.

[0054] In this paper, the hydrogenation protection catalyst used in the hydrotreating reaction zone is FZC-103 catalyst, the hydrorefining catalyst is FF-66 catalyst, and the hydrotreating catalyst is FC-16 catalyst.

[0055] In this paper, the isomeric dewaxing catalyst used in the isomeric dewaxing reaction zone is the FIW-20 catalyst.

[0056] In this paper, to standardize the benchmark for target product yield comparison, the feed mass flow rates of the hydrotreating reaction zone and the hydropre-refining reaction zone were set to be the same, and the mass ratio of the middle distillate oil from the first separation unit to the aviation kerosene fraction from the second separation unit was 9:1. The mass yield of bio-aviation fuel was the ratio of the product mass to the sum of the feed rates of the hydrotreating reaction zone and the hydropre-refining reaction zone. The process conditions in Examples 1-4 and Comparative Examples 1-3 are shown in Table 2.

[0057] Table 2 Process Conditions

[0058]

[0059]

[0060] Example 1

[0061] Example 1 uses Figure 1 The process flow shown indicates that the second naphtha fraction is recycled back to the hydrotreating reaction zone for hydrotreating together with the bio-oil. The raw materials used are kitchen waste oil and medium-temperature coal tar (Table 1), with process conditions shown in Table 2. The properties of the bio-aviation fuel and diesel products are shown in Table 3.

[0062] Example 2

[0063] Example 2 adopts Figure 1 The process flow shown indicates that the second naphtha fraction is recycled back to the hydrotreating reaction zone for hydrotreating together with the bio-oil. The raw materials used are kitchen waste oil and low-temperature coal tar (Table 1), with process conditions shown in Table 2. The properties of the bio-aviation fuel and diesel products are shown in Table 3.

[0064] Example 3

[0065] Example 3 uses Figure 1 The process flow shown indicates that the second naphtha fraction is not recycled back to the hydrotreating reaction zone for hydrotreating together with the bio-oils. Palm oil and medium-temperature coal tar (as shown in Table 1) are used as raw materials; process conditions are shown in Table 2; and the properties of bio-aviation fuel and diesel products are shown in Table 3.

[0066] Example 4

[0067] Example 4 adopts Figure 1 The process flow shown indicates that the second naphtha fraction is recycled back to the hydrotreating reaction zone for hydrotreating together with the bio-oils. Palm oil and low-temperature coal tar (as shown in Table 1) are used as raw materials; process conditions are shown in Table 2; and the properties of bio-aviation fuel and diesel products are shown in Table 3.

[0068] Comparative Example 1

[0069] The process is basically the same as in Example 1, except that the first separation unit separates the oil into two components, while the middle distillate and the first tail oil are not separated and are both processed in the isomerization dewaxing reaction zone. The third separation unit separates the oil into three components: naphtha, jet fuel, and tail oil. The process conditions are shown in Table 2, and the properties of the bio-aviation fuel and diesel products are shown in Table 3.

[0070] Comparative Example 2

[0071] The process is essentially the same as in Example 1, except that the jet fuel fraction obtained from the second separation unit does not enter the isomerization dewaxing reaction zone. Process conditions are shown in Table 2, and the properties of the bio-aviation fuel and diesel products are shown in Table 3.

[0072] Comparative Example 3

[0073] The process is essentially the same as in Example 1, except that a mixture of kitchen waste oil and medium-temperature coal tar is used as raw material in the hydrotreating reaction zone. Instead of a pre-refining hydrotreating reaction zone and a second separation unit, the oil produced in the hydrotreating reaction zone is separated in a third separation unit. The third separation unit yields three components: naphtha, jet fuel, and diesel fuel. Process conditions are shown in Table 2, and the properties of the bio-aviation fuel and diesel fuel are shown in Table 3.

[0074] Table 4. Main Product Properties

[0075]

[0076]

Claims

1. A combined hydrogenation process for producing biofuel, comprising the following steps: (1) In the presence of hydrogen, bio-oil enters the hydrogenation reaction zone for hydrogenation reaction, and the reaction products are separated to obtain the first naphtha fraction, middle distillate oil and the first tail oil. (2) In the presence of hydrogen, coal tar enters the hydrogenation pre-refining reaction zone for hydrogenation reaction. The reaction products are separated to obtain the second naphtha fraction, jet fuel fraction, diesel fraction, and second tail oil; (3) In the presence of hydrogen, the first tail oil and the second tail oil enter the hydrogenation reforming reaction zone for hydrogenation reaction. After the reaction, the hydrogenated reformed product oil is separated from the reaction products obtained in the hydrogenation pre-refining reaction zone in step (2); (4) In the presence of hydrogen, the intermediate distillate oil obtained in step (1) and the aviation kerosene fraction obtained in step (2) enter the isomerization dewaxing reaction zone to react, and the reaction products are separated to obtain naphtha and bio-aviation fuel.

2. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The bio-oil mentioned in step (1) is one or more of vegetable oil, animal oil, and waste oil.

3. The combined hydrogenation process for producing bio-aviation fuel according to claim 2, wherein, The vegetable oil is selected from at least one of soybean oil, rapeseed oil, palm oil, cottonseed oil, and jatropha oil; the animal oil is selected from at least one of lard, tallow, mutton fat, and fish oil; and the waste oil comes from at least one of acidified oil, kitchen waste oil, gutter oil, and swill oil.

4. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The water content of the bio-oil in step (1) is not higher than 300 ppm.

5. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The hydrogenation reaction zone in step (1) is filled with a hydrogenation refining catalyst, and preferably also includes a hydrogenation protection catalyst. The hydrogenation protection catalyst and the hydrogenation refining catalyst are filled in sequence according to the direction of liquid phase material flow. Furthermore, the volume ratio of the hydrogenation protection catalyst to the hydrogenation refining catalyst is 1:20 to 1:

2.

6. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The process conditions for the hydrogenation reaction zone in step (1) are as follows: reaction temperature is 180℃~380℃, preferably 240℃~320℃; hydrogen partial pressure is 1.0MPa~10.0MPa, preferably 3.0~8.0MPa; and volume hourly space velocity is 0.1h. -1 ~4.0h -1 Preferably 0.4h -1 ~2.0h -1 The hydrogen-to-oil volume ratio is 100:1 to 3000:1, preferably 600:1 to 1500:

1.

7. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, In step (1), the cutting temperature of the first naphtha fraction and the middle distillate is 100℃~120℃; the cutting temperature of the middle distillate and the first tail oil is 320℃~340℃.

8. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The coal tar in step (2) is selected from one or more of low-temperature coal tar, medium-temperature coal tar, and high-temperature coal tar.

9. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The hydrogenation pre-purification reaction zone in step (2) is filled with a hydrogenation purification catalyst, preferably also including a hydrogenation protection catalyst. The hydrogenation protection catalyst and the hydrogenation purification catalyst are filled in sequence according to the direction of liquid phase material flow. The volume ratio of the hydrogenation protection catalyst to the hydrogenation purification catalyst is 1:20 to 1:

6.

10. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The process conditions for the hydrogenation pre-purification reaction zone in step (2) are as follows: reaction temperature is 220℃~420℃, preferably 260℃~380℃; hydrogen partial pressure is 5.0MPa~20.0MPa, preferably 8.0~16.0MPa; and volume hourly space velocity is 0.1h. -1 ~6.0h -1 Preferably 0.5h -1 ~2.5h -1 The hydrogen-to-oil volume ratio is 100:1 to 2000:1, preferably 400:1 to 1000:

1.

11. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The final boiling point of the second naphtha fraction in step (2) is 140℃~180℃; the final boiling point of the jet fuel fraction is 220℃~260℃; and the final boiling point of the diesel fraction is 340℃~380℃.

12. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The second naphtha fraction in step (2) is recycled back to the hydrotreating reaction zone and processed together with the bio-oil.

13. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The process conditions for the hydrotreating reaction zone in step (3) are as follows: reaction temperature is 180℃~450℃, preferably 270℃~380℃; hydrogen partial pressure is 5.0MPa~20.0MPa, preferably 8.0~16.0MPa; and volume hourly space velocity is 0.1h. -1 ~6.0h -1 Preferably 0.5h -1 ~3.0h -1 The hydrogen-to-oil volume ratio is 100:1 to 3000:1, preferably 600:1 to 1200:

1.

14. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, In step (3), the hydrotreating reaction zone is sequentially filled with a hydroprotecting catalyst, a hydrorefining catalyst, and a hydrotreating catalyst in the direction of liquid phase material flow; wherein, the total volume ratio of the hydrorefining catalyst and the hydrotreating catalyst to the volume ratio of the hydroprotecting catalyst is 10:1 to 10:3, and the volume ratio of the hydrorefining catalyst to the hydrotreating catalyst is 1:9 to 9:

1.

15. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The mass ratio of the intermediate distillate oil obtained in step (1) to the jet fuel distillate obtained in step (2) in step (4) is 4:1 to 99:1, preferably 6:1 to 19:

1.

16. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The isomerization dewaxing reaction zone in step (4) is filled with isomerization dewaxing catalyst.

17. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The process conditions for the isomerization decondensation reaction zone in step (4) are as follows: reaction temperature is 180℃~420℃, preferably 240℃~350℃; hydrogen partial pressure is 0.05MPa~30MPa, preferably 2.0~15.0MPa; and volume hourly space velocity is 0.1h. -1 ~6.0h -1 Preferably 0.5h -1 ~4.0h -1 The hydrogen-to-oil volume ratio is 100:1 to 3000:1, preferably 500:1 to 1500:

1.

18. The combined hydrogenation process for producing bio-aviation fuel according to claim 1, wherein, The final boiling point of the naphtha in step (4) is controlled to be 120℃~140℃.

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