A process for the production of liquid fuels from soapstock in two stages of hydrogenation

Abstract

The application discloses a method for preparing liquid fuel by two-stage hydrogenation of soapstock, and belongs to the field of soapstock recycling and reuse. The method adopts a two-stage reactor in series, hydrogenation pyrolysis of soapstock is carried out in a first-stage reactor, and catalytic hydrogenation deoxygenation reaction of pyrolysis volatile products is carried out in a second-stage reactor, so that liquid fuel is finally obtained. The method has mild reaction conditions, a simple process, low hydrogen consumption, and improved stability of the catalyst, and can achieve excellent hydrogenation deoxygenation effect under low pressure, and the prepared liquid fuel is free of oxygen-containing products and is normal alkanes with carbon numbers of 5 to 19, and the yield can reach 86% at the highest. The method can realize high-value utilization of soapstock, and can relieve energy shortage and environmental pollution.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of soapstock recycling and reusing, and particularly relates to a method for preparing liquid fuel by two-stage hydrogenation of soapstock. BACKGROUND

[0002] With the continuous development of industrialization, modernization and globalization, the global demand for energy has increased dramatically. According to statistics, the global energy consumption in 2020 reached 556.63 EJ, and it is expected to grow by 12.3% by 2050. However, more than 80% of the global energy consumption today comes from fossil energy that is close to exhaustion. In addition, the widespread consumption of fossil energy has caused many environmental problems such as acid rain, ozone layer destruction and global warming that need to be solved. According to statistics, the carbon dioxide emissions from the use of fossil energy in 2019 accounted for 64% of the total global emissions. Therefore, in order to cope with the problem of dwindling energy and the problem of affecting the environment, the best alternative fuel needs to be found. Biomass has been widely concerned because of its renewability and carbon neutrality. It is estimated that by 2050, global biomass will account for 18% of final energy consumption. Biofuels produced from biomass are also considered to be sustainable and environmentally friendly, and it is estimated that by 2050, 27% of transportation fuels (including gasoline, diesel and aviation coal) will be replaced by biofuels. Among the many production raw materials, waste oil and fat biomass has become a research hotspot because of its high energy density, not competing with people for food and not competing with land for food, etc.

[0003] Soapstock is a by-product of vegetable oil refining process, which is a kind of waste oil biomass, mainly composed of fatty acid salts and neutral oil. The yield of soapstock accounts for 5%-10% of the vegetable oil. With the increasing demand for edible oil, the annual production of soapstock in China is nearly 5 million tons. However, except for a small amount of soapstock used for synthesizing detergents, producing feed and preparing acidified oil, a large amount of soapstock is discarded, which causes resource waste and environmental pollution. Therefore, soapstock has become a resource that needs to be recycled and reused. A promising method for recycling soapstock is to produce biofuels, which can alleviate environmental pollution and fossil energy depletion. At present, various technologies have been developed for producing biofuels from soapstock, including ester exchange, hydrogenation and pyrolysis, etc. Both ester exchange and hydrogenation of soapstock require a one-step pretreatment, i.e. acidification of soapstock into acidified oil, and then ester exchange and hydrogenation of acidified oil, respectively. Invention patent CN 103820224 A discloses a kind of biodiesel and its preparation method. The method first acidifies soapstock into acidified oil, and then methyl esterification and ester exchange of acidified oil with methanol under the action of catalyst to prepare high-quality biodiesel. However, ester exchange method consumes a large amount of methanol and produces waste glycerol. In addition, the high oxygen content and poor cold flow performance of biodiesel limit its further development. Invention patent CN107118791 A discloses a method for preparing alkane type biodiesel from soapstock. The method first acidifies soapstock into acidified oil, and then catalytic hydrogenation of acidified oil to prepare high-quality alkane type biodiesel. However, acidification of oil hydrogenation is an intermittent reaction in a high-pressure (>1 MPa) reactor, and organic solvent is needed to dissolve oil to increase the flowability of the reaction system. This method has the disadvantages of harsh process conditions, easy deactivation of catalyst, easy pollution and low production efficiency.

[0004] To solve the above-mentioned problems of oil hydrogenation, researchers optimize the oil hydrogenation deoxidation process by adopting multi-stage reactor continuous reaction, introducing circulating material and improving catalyst stability and other ways. Invention patent CN106281401B discloses a method for producing aviation biofuel from waste animal and vegetable oil. The method first pretreats the waste oil to remove impurities and reduce acid value, then carries out hydrogenation deoxidation reaction under the process conditions of 1∶1-8∶1 mass ratio of circulating refined oil to fresh raw material and 3-15 MPa pressure, and then carries out cracking and isomerization in the hydrogenation conversion unit to prepare C15-C18 alkanes. Invention patent CN107974266B discloses a method for producing aviation fuel components from waste oil. The method first methyl esterifies the waste oil to produce fatty acid methyl ester, which can reduce the acid value of the waste oil and remove impurities. Then, the refined methyl ester is subjected to hydrogenation deoxidation reaction in a hydrogenation treatment reaction unit under the conditions of 1.0-10.0 MPa pressure and 1∶2-1∶6 mass ratio of refined methyl ester to circulating liquid material. The product is then subjected to hydrocracking in a hydrogenation conversion reaction unit to obtain alkanes. Invention patent CN103059901B discloses a method for preparing diesel fuel components or jet fuel components from animal and vegetable oil. The method first carries out hydrogenation deoxidation reaction on the oil in a first hydrogenation reactor composed of multiple catalyst beds to obtain C8-C24 n-alkanes, with hydrogenation deoxidation pressure of 1-7 MPa and circulating oil to raw material volume ratio less than 2:1. Then, the product is subjected to hydrocracking and isomerization in a second hydrogenation reactor to obtain jet fuel. In summary, there are two main defects in the current oil hydrogenation deoxidation process. One is that the hydrogenation deoxidation reaction is still carried out in liquid state, which requires high pressure to dissolve hydrogen in oil and long reaction time, making the reaction conditions harsh. The other is that the hydrogenation deoxidation catalyst is not stable. Pretreatment and methyl esterification of oil are carried out to prevent catalyst deactivation caused by impurities. Designing multiple layers of catalyst and increasing the circulation ratio during hydrogenation deoxidation process are also to improve the stability of the catalyst and make the process run for a long period. However, the catalyst still faces the risk of deactivation.

[0005] Pyrolysis refers to the cracking of oil and fat into small-molecule compounds under anaerobic high temperature, including organic liquid products, gaseous compounds, water and coke. Catalytic pyrolysis is carried out under catalyst, which can reduce the oxygen content of liquid products. Invention patent CN112410118A discloses a thermochemical pretreatment method of waste oil and fat or soapstock. The method first acidifies the soapstock into acidified oil, and then carries out catalytic cracking of the acidified oil to prepare a high-yield cracking oil. The method has the advantages of high cracking efficiency and low content of impurity elements in the product, but still contains more than 6.78% oxygen content. Invention patent CN107903931A discloses a method for preparing rich-hydrocarbon bio-oil and biochar by microwave-assisted double-bed co-catalytic fast pyrolysis of soybean soapstock. The method directly mixes the catalyst with the soapstock into double beds, and carries out co-catalytic pyrolysis under microwave assistance to prepare rich-hydrocarbon bio-oil. The method has the advantages of high bio-oil yield and high hydrocarbon content, but still contains a small amount of oxygen-containing compounds in the bio-oil. Therefore, there are still some problems in the current catalytic cracking process of oil and fat. First, catalytic cracking of oil and fat can reduce the oxygen content of liquid products to a certain extent, but the liquid products still contain oxygen, which makes the liquid fuel have low calorific value and unstable storage performance. Second, the process itself removes oxygen in the form of decarbonylation, decarboxylation and dehydration during the reaction process, which increases the yield of gas and coke and reduces the recovery rate of liquid carbon. Finally, most of the processes belong to in-situ catalytic cracking, and pyrolysis and catalytic reforming are carried out at the same temperature, which limits the optimization of the catalytic reforming temperature. Inorganic components in oil and fat and coke formed by catalytic cracking also easily cause the deactivation of the catalyst.

[0006] In order to obtain high-quality liquid fuel, researchers combine the above two processes together, and carry out catalytic cracking and catalytic hydrodeoxygenation of oil and fat in two reactors in turn. Invention patent CN102746871B discloses a novel method for preparing fuel from biological oil and fat. The method first carries out catalytic cracking and deoxygenation reaction on biological oil and fat, and then carries out catalytic hydrodeoxygenation reaction on the product to manufacture clean fuel comparable to fuel components obtained by crude oil refining. Invention patent CN103468300A discloses a process method for producing clean fuel by catalytic cracking and hydrogenation of animal and vegetable oil and fat. The method sequentially carries out catalytic cracking reaction and catalytic hydrogenation reaction on oil and fat, and then enters a rectifying column to be cut into various biofuels. Although this process can obtain liquid fuel with good quality, the process still has the problems encountered when the two reactors work separately. In addition, product separation, condensation and other steps are needed between the two reactors, and the process is complicated.

[0007] In summary, for the existing process of preparing liquid fuel by hydrodeoxygenation of oil, liquid hydrodeoxygenation reaction is carried out, and high-pressure reaction environment is required, and the reaction conditions are harsh; in addition, the process itself also causes poor stability of the catalyst, and it is difficult to operate for a long period. For the existing process of preparing liquid fuel by catalytic cracking of oil, there are still problems of poor product oil, low liquid carbon recovery rate and easy deactivation of the catalyst. For the existing process combining catalytic cracking and catalytic hydrodeoxygenation, in addition to the problems of separate operation, there is also the problem of complicated process. SUMMARY

[0008] In view of the problems in the prior art, the technical problem to be solved by the present application is to provide a method for preparing liquid fuel by two-stage hydrogenation of soapstock, which has the advantages of mild process reaction conditions, simple process, high-quality liquid fuel without oxygen, and improved stability of the catalyst, solves the problems of harsh reaction conditions and easy deactivation of the catalyst caused by liquid hydrodeoxygenation reaction in the existing process of preparing liquid fuel by hydrodeoxygenation of soapstock, and solves the problems of poor product oil, low liquid carbon recovery rate and easy deactivation of the catalyst in the existing process of preparing liquid fuel by catalytic cracking of soapstock.

[0009] In order to solve the above problems, the technical scheme adopted by the present application is as follows:

[0010] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, which adopts a series two-stage reactor, carries out hydrogen pyrolysis of soapstock in a first-stage reactor, and carries out catalytic hydrodeoxygenation reaction of pyrolysis volatile products in a second-stage reactor, and finally obtains liquid fuel; the hydrodeoxygenation catalyst is any one of 25% Ni / Al2O3-SiO2 (25% refers to the loading amount of Ni), 10% Ni / Al2O3 (10% refers to the loading amount of Ni), 5% Pt / Al2O3 (5% refers to the loading amount of Pt), 5% Pd / C (5% refers to the loading amount of Pd) or 10% Ni / LaCoO3 (10% refers to the loading amount of Ni).

[0011] The method for preparing liquid fuel by two-stage hydrogenation of soapstock comprises the following steps:

[0012] (1) loading the hydrodeoxygenation catalyst into a quartz tube, and filling the quartz tube into the second-stage reactor; loading the soapstock into a sample bottle, and filling the sample bottle into the sample inlet; connecting the carrier gas, the reaction gas and the reaction device, and purging the first-stage reactor and the second-stage reactor in the series two-stage reactor through the sample filling for 3-7 min;

[0013] (2) switching to continue purging the first-stage reactor and the second-stage reactor in the series two-stage reactor with the reaction gas for 10-15 min, setting the reaction temperature and pressure of the first-stage reactor and the second-stage reactor, and starting heating to heat the first-stage reactor and the second-stage reactor;

[0014] (3) When the reactor temperature and pressure reach the set values, the sample bottle containing the soapstock is sent into the first reactor for hydrothermal pyrolysis, and the pyrolysis volatile products enter the second reactor along with the reaction gas for catalytic hydrodeoxygenation reaction, and liquid fuel is obtained after the reaction is completed.

[0015] The method for preparing liquid fuel by two-stage hydroprocessing of soapstock, wherein the carrier gas is helium or hydrogen, and the reaction gas is hydrogen; and the flow rate of the reaction gas or carrier gas is 70-160 ml / min.

[0016] The method for preparing liquid fuel by two-stage hydroprocessing of soapstock, wherein the set temperature of the first reactor is 450-600 DEG C, and the set temperature of the second reactor is 270-350 DEG C, and the pressure is 1-20 bar.

[0017] The method for preparing liquid fuel by two-stage hydroprocessing of soapstock, wherein the mass ratio of soapstock to hydrodeoxygenation catalyst is 3:5-1:4.

[0018] The method for preparing liquid fuel by two-stage hydroprocessing of soapstock, wherein the set temperature of the first reactor is 550 DEG C, the set temperature of the second reactor is 300 DEG C, and the pressure is 2.5 bar.

[0019] The method for preparing liquid fuel by two-stage hydroprocessing of soapstock, wherein the hydrodeoxygenation catalyst is 5% Pd / C, and the mass ratio of soapstock to catalyst is 1:4.

[0020] The method for preparing liquid fuel by two-stage hydroprocessing of soapstock, wherein the soapstock is one or a mixture of several of coconut oil, peanut oil, palm oil, rapeseed oil, soybean oil or peony seed oil soapstock.

[0021] Advantages: Compared with the prior art, the advantages of the present application include:

[0022] (1) The present application performs primary hydrothermal pyrolysis of soapstock in the first reactor, and the volatile products obtained are directly introduced into the second reactor for gas-phase catalytic hydrodeoxygenation reaction. The hydrothermal pyrolysis process and the catalytic hydrodeoxygenation process do not affect each other, and the two process conditions can be adjusted as needed to obtain the best reaction conditions. The generation of permanent gases can be reduced by adjusting the soapstock through the hydrothermal pyrolysis process, and the decarboxylation and decarbonylation reactions can be inhibited by adjusting the catalytic hydrodeoxygenation process, thereby improving the carbon recovery rate of liquid products. The gas-phase products obtained by hydrothermal pyrolysis can be uniformly mixed with hydrogen, thereby making it easier to perform hydrodeoxygenation reaction on the hydrodeoxygenation catalyst. The present application can achieve better deoxygenation effect at low pressure, and has the advantages of mild reaction conditions, less hydrogen consumption, and good deoxygenation effect.

[0023] (2) The hydrodeoxygenation catalyst of the present application can be reused, and the stability is greatly improved. The two-stage hydrogenation of the present application belongs to the mode of hydrothermal cracking and non-in-situ catalytic hydrodeoxygenation, and the impurities of soapstock cannot enter the secondary reactor, thereby avoiding the poisoning of the catalyst. In addition, the hydrogen in the reactor can saturate the reactive intermediates of the pyrolysis products, prevent the polymerization of the intermediates, avoid the generation of coke on the catalyst, and improve the stability of the catalyst.

[0024] (3) The process of the present application is simple, and does not need to design multi-layer catalysts and circulating materials, nor does it need to go through the steps of soapstock pretreatment, product separation, condensation collection, etc. The volatile products of soapstock pyrolysis directly enter the secondary reactor for catalytic hydrodeoxygenation reaction, and the impurities and solid products remain in the primary reactor.

[0025] (4) The liquid fuel component prepared by the present application is C5-C19 n-alkane, which can be distilled into bio-gasoline, bio-jet fuel and bio-diesel, and can be mixed with transportation fuel at any ratio. The liquid fuel has no oxygen-containing products, and the yield can be as high as 86%. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below. The two-stage hydrogenation of soapstock to prepare liquid fuel is carried out on a micro-reactor (RX3050TR, Japan Frontier Laboratories) and a gas chromatography-mass spectrometry device.

[0027] Comparative Example 1

[0028] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0029] (1) 3 mg of peony seed oil soapstock is loaded into a sample bottle, and the sample bottle is filled into the sample inlet; then the carrier gas helium is introduced to sweep the primary reactor and the secondary reactor in the series two-stage reactor for 4 min at a flow rate of 120 ml / min;

[0030] (2) The helium is switched to hydrogen, and the primary reactor and the secondary reactor in the series two-stage reactor are swept for 10 min, and then the temperature of the primary reactor is set to 500℃ and the temperature of the secondary reactor is set to 300℃ by the computer end, and the reaction pressure is 2 bar, at this time the reactor starts to heat and pressurize;

[0031] (3) After observing that the reactor temperature and pressure are stable to the set values and the gas chromatography-mass spectrometer is in working condition, the sample bottle containing the peony seed oil soapstock is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile products enter the second reactor for catalytic hydrodeoxygenation reaction, and the products obtained after the reaction enter the separation device, pass through the separation column, and enter the gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0032] As shown in Table 1, under the condition of no hydrodeoxygenation catalyst, the oxygen-containing product concentration in the liquid fuel prepared by two-stage hydrogenation of the peony seed oil soapstock is 55.3%, and the yield of C5-C19 is only 7.5%; the three data results of bio-gasoline selectivity, bio-jet fuel selectivity, and bio-diesel selectivity are not counted in Table 1, because the yield of C5-C19 is too low, and it is meaningless to explore the selectivity of bio-diesel, bio-gasoline, and bio-jet fuel.

[0033] Example 1

[0034] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0035] (1) 12 mg of 25% Ni / Al2O3-SiO2 catalyst is loaded into a quartz tube, and the quartz tube is loaded into the second reactor; 3 mg of peony seed oil soapstock is loaded into a sample bottle, and the sample bottle is loaded into the sample inlet; then the carrier gas helium is introduced at a flow rate of 120 ml / min to purge the first reactor and the second reactor in the two-stage reactor for 4 min;

[0036] (2) The helium is switched to hydrogen, and the first reactor and the second reactor in the two-stage reactor are purged for 10 min, and then the temperature of the first reactor is set to 500°C and the temperature of the second reactor is set to 300°C by the computer, and the reaction pressure is 2 bar, at this time the reactor starts to heat and pressurize;

[0037] (3) After observing that the reactor temperature and pressure are stable to the set values and the gas chromatography-mass spectrometer is in working condition, the sample bottle containing the peony seed oil soapstock is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile products enter the second reactor for catalytic hydrodeoxygenation reaction, and the products obtained after the reaction enter the separation device, pass through the separation column, and enter the gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0038] As shown in Table 1, under the catalysis of the 25% Ni / Al2O3-SiO2 catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the peony seed oil soapstock has no oxygen-containing product, is C5-C19 normal alkane, and the yield is 72.2%; the selectivity for the bio-gasoline (C5-C12 normal alkane) is 41.6%, the selectivity for the bio-jet fuel (C8-C16 normal alkane) is 57.6%, and the selectivity for the bio-diesel (C10-C19 normal alkane) is 74.6%.

[0039] Example 2

[0040] A method for preparing a liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0041] (1) 12 mg of 25% Ni / Al2O3-SiO2 catalyst is loaded into a quartz tube, and the quartz tube is loaded into a two-stage reactor; 3 mg of peony seed oil soapstock is loaded into a sample bottle, and the sample bottle is loaded into a sample inlet; then, helium gas is introduced at a flow rate of 140 ml / min to purge the first-stage reactor and the second-stage reactor in the two-stage reactor for 3 min;

[0042] (2) The helium gas is switched to hydrogen gas, and the first-stage reactor and the second-stage reactor in the two-stage reactor are purged for 13 min, and then the temperature of the first-stage reactor is set to 550°C, the temperature of the second-stage reactor is set to 300°C, and the reaction pressure is set to 2.5 bar by a computer terminal, at which time the reactor starts to increase the temperature and the pressure;

[0043] (3) After observing that the temperature and the pressure of the reactor are stable to the set values, and the gas chromatography-mass spectrometry is in the working state, the sample bottle loaded with the peony seed oil soapstock is sent into the first-stage reactor for the hydro- pyrolysis, the pyrolysis volatile product enters the second-stage reactor for the catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters a separation device, passes through a separation column, and enters a gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0044] As shown in Table 1, under the catalysis of the 25% Ni / Al2O3-SiO2 catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the peony seed oil soapstock has no oxygen-containing product, is C5-C19 normal alkane, and the yield is 72.2%; the selectivity for the bio-gasoline (C5-C12 normal alkane) is 41.6%, the selectivity for the bio-jet fuel (C8-C16 normal alkane) is 57.6%, and the selectivity for the bio-diesel (C10-C19 normal alkane) is 74.6%.

[0045] Example 3

[0046] A method for preparing a liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0047] (1) Put 7 mg of 25% Ni / Al2O3-SiO2 catalyst into a quartz tube, and load the quartz tube into the secondary reactor; put 3 mg of peony seed oil soapstock into a sample bottle, and load the sample bottle into the sample inlet; then introduce carrier gas helium at a flow rate of 150 ml / min through the sample loading site to purge the first reactor and the second reactor in the two-stage reactor for 5 min;

[0048] (2) Switch the helium to hydrogen, and purge the first reactor and the second reactor in the two-stage reactor for 14 min, and then set the temperature of the first reactor to 550°C and the temperature of the second reactor to 300°C through the computer terminal, and set the reaction pressure to 2.5 bar, at which time the reactor starts to increase the temperature and the pressure;

[0049] (3) After observing that the temperature and the pressure of the reactor are stable to the set values, and the gas chromatograph-mass spectrometer is in working condition, the sample bottle containing the peony seed oil soapstock is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile product enters the second reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters the separation device, passes through the separation column, and enters the gas chromatograph-mass spectrometer for online analysis, and the results are shown in Table 1.

[0050] As shown in Table 1, under the catalysis of the 25% Ni / Al2O3-SiO2 catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the peony seed oil soapstock has no oxygen-containing product, is C5-C19 n-alkane, and the yield is 74.8%; the selectivity for the bio-gasoline is 38.2%, the selectivity for the bio-jet fuel is 51.1%, and the selectivity for the bio-diesel is 75.4%.

[0051] Example 4

[0052] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0053] (1) Put 7 mg of 25% Ni / Al2O3-SiO2 catalyst into a quartz tube, and load the quartz tube into the secondary reactor; put 3 mg of peony seed oil soapstock into a sample bottle, and load the sample bottle into the sample inlet; then introduce carrier gas helium at a flow rate of 150 ml / min through the sample loading site to purge the first reactor and the second reactor in the two-stage reactor for 5 min;

[0054] (2) Switch the helium to hydrogen, and purge the first reactor and the second reactor in the two-stage reactor for 14 min, and then set the temperature of the first reactor to 550°C and the temperature of the second reactor to 300°C through the computer terminal, and set the reaction pressure to 2.5 bar, at which time the reactor starts to increase the temperature and the pressure;

[0055] (3) After observing that the reactor temperature and pressure are stable to the set values and the gas chromatography-mass spectrometer is in working condition, the sample bottle containing the coconut oil soapstock is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile product enters the second reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters the separation device, passes through the separation column, and enters the gas chromatography-mass spectrometer for online analysis. The results are shown in Table 1.

[0056] As shown in Table 1, under the catalysis of the 25% Ni / Al2O3-SiO2 catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the coconut oil soapstock has no oxygen-containing product, is a normal alkane of C5-C19, and the yield is 72.8%; the selectivity for the bio-gasoline is 95.6%, the selectivity for the bio-jet fuel is 49.5%, and the selectivity for the bio-diesel is 27.7%.

[0057] Example 5

[0058] A method for preparing a liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0059] (1) 12 mg of 25% Ni / Al2O3-SiO2 catalyst is loaded into a quartz tube, and the quartz tube is loaded into the second reactor; 3 mg of peanut oil soapstock is loaded into a sample bottle, and the sample bottle is loaded into the sample inlet; then helium gas is introduced as the carrier gas at a flow rate of 100 ml / min to purge the first reactor and the second reactor in the two-stage reactor for 6 min;

[0060] (2) The helium gas is switched to hydrogen gas, and the first reactor and the second reactor in the two-stage reactor are purged for 12 min, and then the temperature of the first reactor is set to 550°C and the temperature of the second reactor is set to 300°C by the computer, and the reaction pressure is set to 2.5 bar, at which time the reactor starts to increase the temperature and the pressure;

[0061] (3) After observing that the reactor temperature and pressure are stable to the set values and the gas chromatography-mass spectrometer is in working condition, the sample bottle containing the peanut oil soapstock is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile product enters the second reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters the separation device, passes through the separation column, and enters the gas chromatography-mass spectrometer for online analysis. The results are shown in Table 1.

[0062] As shown in Table 1, under the catalysis of the 25% Ni / Al2O3-SiO2 catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the peanut oil soapstock has no oxygen-containing product, is a normal alkane of C5-C19, and the yield is 82.6%; the selectivity for the bio-gasoline is 69.2%, the selectivity for the bio-jet fuel is 63.1%, and the selectivity for the bio-diesel is 55.0%.

[0063] Example 6

[0064] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0065] (1) 12 mg of 25% Ni / Al2O3-SiO2 catalyst was loaded into a quartz tube, and the quartz tube was loaded into a two-stage reactor; 3 mg of peony seed oil soapstock was loaded into a sample bottle, and the sample bottle was loaded into a sample inlet; then, helium gas was introduced as a carrier gas at a flow rate of 80 ml / min to purge the first-stage reactor and the second-stage reactor in the two-stage reactor for 4 min;

[0066] (2) The helium gas was switched to hydrogen gas, and the first-stage reactor and the second-stage reactor in the two-stage reactor were purged for 15 min, followed by setting the temperature of the first-stage reactor to 550°C and the temperature of the second-stage reactor to 300°C and the reaction pressure to 2.5 bar through a computer terminal, at which time the reactor began to increase the temperature and pressure;

[0067] (3) After observing that the temperature and pressure of the reactor were stable to the set values, and the gas chromatography-mass spectrometry was in working condition, the sample bottle loaded with the peony seed oil soapstock was sent into the first-stage reactor for hydrothermal pyrolysis, and the pyrolysis volatile product entered the second-stage reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction entered a separation device, passed through a separation column, and entered a gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0068] As shown in Table 1, under the catalysis of the 25% Ni / Al2O3-SiO2 catalyst, the liquid fuel prepared by two-stage hydrogenation of the soybean oil soapstock was free of oxygen-containing products, was C5-C19 n-alkane, and the yield was 82.9%; the selectivity for bio-gasoline was 57.8%, the selectivity for bio-jet fuel was 61.8%, and the selectivity for bio-diesel was 63.8%.

[0069] Example 7

[0070] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0071] (1) 12 mg of 25% Ni / Al2O3-SiO2 catalyst was loaded into a quartz tube, and the quartz tube was loaded into a two-stage reactor; 3 mg of peony seed oil soapstock was loaded into a sample bottle, and the sample bottle was loaded into a sample inlet; then, helium gas was introduced as a carrier gas at a flow rate of 80 ml / min to purge the first-stage reactor and the second-stage reactor in the two-stage reactor for 4 min;

[0072] (2) Switch helium to hydrogen, and purge the first reactor and the second reactor in the two-stage reactor for 10 min, then set the first reactor temperature to 550℃, the second reactor temperature to 300℃, and the reaction pressure to 2.5 bar through the computer terminal, at which time the reactor starts to increase the temperature and the pressure;

[0073] (3) After observing that the reactor temperature and the pressure are stable to the set values, and the gas chromatography-mass spectrometer is in working condition, the sample bottle containing the soapstock of peony seed oil is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile product enters the second reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters the separation device, passes through the separation column, and enters the gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0074] As shown in Table 2, under the catalysis of the 10% Ni / Al2O3 catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the soapstock of peony seed oil has no oxygen-containing product, is C5-C19 normal alkane, and the yield is 79.1%; the selectivity for bio-gasoline is 38.5%, the selectivity for bio-jet fuel is 50.5%, and the selectivity for bio-diesel is 74.9%.

[0075] Example 8

[0076] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0077] (1) 12 mg of 5% Pt / Al2O3 catalyst is loaded into a quartz tube, and the quartz tube is loaded into the second reactor; 3 mg of soapstock of peony seed oil is loaded into a sample bottle, and the sample bottle is loaded into the sample inlet; then helium is introduced as the carrier gas at a flow rate of 90 ml / min to purge the first reactor and the second reactor in the two-stage reactor for 7 min;

[0078] (2) Switch helium to hydrogen, and purge the first reactor and the second reactor in the two-stage reactor for 11 min, then set the first reactor temperature to 550℃, the second reactor temperature to 300℃, and the reaction pressure to 2.5 bar through the computer terminal, at which time the reactor starts to increase the temperature and the pressure;

[0079] (3) After observing that the reactor temperature and the pressure are stable to the set values, and the gas chromatography-mass spectrometer is in working condition, the sample bottle containing the soapstock of peony seed oil is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile product enters the second reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters the separation device, passes through the separation column, and enters the gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0080] As shown in Table 2, under the catalysis of 5% Pt / Al2O3 catalyst, the liquid fuel prepared by two-stage hydrogenation reaction of peony seed oil soapstock has no oxygen-containing product, is C5-C19 normal alkane, and the yield is 85.5%; the selectivity for bio-gasoline is 38.3%, the selectivity for bio-jet fuel is 50.2%, and the selectivity for bio-diesel is 75.2%.

[0081] Example 9

[0082] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0083] (1) 12 mg of 5% Pd / C catalyst is loaded into a quartz tube, and the quartz tube is loaded into a two-stage reactor; 3 mg of peony seed oil soapstock is loaded into a sample bottle, and the sample bottle is loaded into a sample inlet; then helium gas is introduced as a carrier gas at a flow rate of 110 ml / min to purge the first-stage reactor and the second-stage reactor in the two-stage reactor for 6 min;

[0084] (2) The helium gas is switched to hydrogen gas, and the first-stage reactor and the second-stage reactor in the two-stage reactor are purged for 12 min, and then the temperature of the first-stage reactor is set to 550°C, the temperature of the second-stage reactor is set to 300°C, and the reaction pressure is set to 2.5 bar by a computer terminal, at which time the reactor starts to increase the temperature and the pressure;

[0085] (3) After observing that the temperature and the pressure of the reactor are stable to the set values, and the gas chromatography-mass spectrometry is in working condition, the sample bottle loaded with peony seed oil soapstock is sent into the first-stage reactor for hydrothermal pyrolysis, and the pyrolysis volatile product enters the second-stage reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters a separation device, passes through a separation column, and enters a gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0086] As shown in Table 2, under the catalysis of 5% Pd / C catalyst, the liquid fuel prepared by two-stage hydrogenation reaction of peony seed oil soapstock has no oxygen-containing product, is C5-C19 normal alkane, and the yield is 86.4%; the selectivity for bio-gasoline is 36.0%, the selectivity for bio-jet fuel is 49.0%, and the selectivity for bio-diesel is 77.1%.

[0087] Example 10

[0088] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0089] (1) 12 mg 10% Ni / LaCoO3 catalyst was loaded into a quartz tube, and the quartz tube was packed into the secondary reactor; 3 mg of peony seed oil soapstock was loaded into a sample bottle, and the sample bottle was packed into the sample inlet; then helium carrier gas was introduced at a flow rate of 130 ml / min to purge the first reactor and the second reactor in the two-stage reactor for 5 min;

[0090] (2) Switch the helium to hydrogen, and purge the first reactor and the second reactor in the two-stage reactor for 13 min, and then set the temperature of the first reactor to 550°C and the temperature of the second reactor to 300°C through the computer terminal, and the reaction pressure is 2.5 bar, at which time the reactor starts to heat and pressurize;

[0091] (3) After observing that the temperature and pressure of the reactor are stable to the set values, and the gas chromatograph-mass spectrometer is in working condition, the sample bottle containing the peony seed oil soapstock is sent into the first reactor for hydrothermal pyrolysis, and the pyrolysis volatile product enters the second reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters the separation device, passes through the separation column, and enters the gas chromatograph-mass spectrometer for online analysis, and the results are shown in Table 1.

[0092] As shown in Table 2, under the catalysis of the 10% Ni / LaCoO3 catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the peony seed oil soapstock has no oxygen-containing product, is a normal alkane with C5-C19, and the yield is 81.4%; the selectivity for bio-gasoline is 36.7%, the selectivity for bio-jet fuel is 49.4%, and the selectivity for bio-diesel is 76.7%.

[0093] Example 11

[0094] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0095] (1) 5 mg of 5% Pt / Al2O3 catalyst was loaded into a quartz tube, and the quartz tube was packed into the secondary reactor; 3 mg of peony seed oil soapstock was loaded into a sample bottle, and the sample bottle was packed into the sample inlet; then helium carrier gas was introduced at a flow rate of 150 ml / min to purge the first reactor and the second reactor in the two-stage reactor for 4 min;

[0096] (2) Switch the helium to hydrogen, and purge the first reactor and the second reactor in the two-stage reactor for 14 min, and then set the temperature of the first reactor to 550°C and the temperature of the second reactor to 300°C through the computer terminal, and the reaction pressure is 2.5 bar, at which time the reactor starts to heat and pressurize;

[0097] (3) After observing that the temperature and pressure of the reactor are stable to the set values and the gas chromatography-mass spectrometer is in working condition, the sample bottle containing the soapstock of peony seed oil is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile product enters the second reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters the separation device, passes through the separation column, and enters the gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0098] As shown in Table 2, under the catalysis of the 5% Pt / Al2O3 catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the soapstock of peony seed oil has no oxygen-containing product, is n-alkane of C5-C19, and the yield is 79.0%; the selectivity for bio-gasoline is 38.5%, the selectivity for bio-jet fuel is 50.5%, and the selectivity for bio-diesel is 74.9%.

[0099] Example 12

[0100] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0101] (1) 5 mg of 5% Pd / C catalyst is loaded into a quartz tube, and the quartz tube is loaded into the second reactor; 3 mg of soapstock of peony seed oil is loaded into a sample bottle, and the sample bottle is loaded into the sample inlet; then helium gas is introduced as the carrier gas at a flow rate of 135 ml / min to purge the first reactor and the second reactor in the two-stage reactor for 3 min;

[0102] (2) The helium gas is switched to hydrogen gas, and the first reactor and the second reactor in the two-stage reactor are purged for 15 min, and then the temperature of the first reactor is set to 550°C and the temperature of the second reactor is set to 300°C by the computer, and the reaction pressure is set to 2.5 bar, at which time the reactor starts to increase the temperature and pressure;

[0103] (3) After observing that the temperature and pressure of the reactor are stable to the set values and the gas chromatography-mass spectrometer is in working condition, the sample bottle containing the soapstock of peony seed oil is sent into the first reactor for hydrothermal pyrolysis, the pyrolysis volatile product enters the second reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction enters the separation device, passes through the separation column, and enters the gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0104] As shown in Table 2, under the catalysis of the 5% Pd / C catalyst, the liquid fuel prepared by the two-stage hydrogenation reaction of the soapstock of peony seed oil has no oxygen-containing product, is n-alkane of C5-C19, and the yield is 80.3%; the selectivity for bio-gasoline is 36.5%, the selectivity for bio-jet fuel is 49.4%, and the selectivity for bio-diesel is 76.6%.

[0105] Example 13

[0106] A method for preparing liquid fuel by two-stage hydrogenation of soapstock, comprising the following steps:

[0107] (1) 5 mg of 10% Ni / LaCoO3 catalyst was loaded into a quartz tube, and the quartz tube was loaded into a two-stage reactor; 3 mg of peony seed oil soapstock was loaded into a sample bottle, and the sample bottle was loaded into a sample inlet; then helium carrier gas was introduced at a flow rate of 115 ml / min to purge the first-stage reactor and the second-stage reactor in the two-stage reactor for 5 min;

[0108] (2) The helium was switched to hydrogen, and the first-stage reactor and the second-stage reactor in the two-stage reactor were purged for 13 min, followed by setting the first-stage reactor temperature to 550°C and the second-stage reactor temperature to 300°C and the reaction pressure to 2.5 bar through a computer terminal, at which time the reactor began to heat and pressurize;

[0109] (3) After observing that the reactor temperature and pressure were stable to the set values, and the gas chromatography-mass spectrometry was in working condition, the sample bottle loaded with peony seed oil soapstock was sent into the first-stage reactor for hydrothermal pyrolysis, and the pyrolysis volatile product entered the second-stage reactor for catalytic hydrodeoxygenation reaction, and the product obtained after the reaction entered a separation device, passed through a separation column, and entered a gas chromatography-mass spectrometer for online analysis, and the results are shown in Table 1.

[0110] As shown in Table 2, under the catalysis of the 10% Ni / LaCoO3 catalyst, the liquid fuel prepared by two-stage hydrogenation of peony seed oil soapstock had no oxygen-containing product, was a normal alkane with C5-C19, and the yield was 76.0%; the selectivity for bio-gasoline was 37.4%, the selectivity for bio-jet fuel was 49.8%, and the selectivity for bio-diesel was 75.9%.

[0111] Example 14

[0112] The catalyst after the reaction of Example 10 was recycled and used for 6 repeated reuse experiments under the same reaction conditions. The repeated reuse results of the catalyst are shown in Table 3.

[0113] Table 1 Experimental results of Comparative Example 1 and Examples 1-6

[0114]

[0115] Table 2 Experimental results of Examples 7-13

[0116]

[0117] Table 3 Repeated use results of 10% Ni / LaCoO3 catalyst o O3 catalyst

[0118]

[0119]

[0120] The formula for calculating C5-C19 n-alkane yield, oxygenate concentration, bio- gasoline selectivity, bio-jet selectivity, and bio-diesel selectivity in Tables 1, 2, and 3 are shown below:

[0121]

[0122]

[0123]

[0124]

[0125]

Claims

1. A process for the production of liquid fuels from soap skimming in two stages by hydrogenation, characterized in that, The serial two-stage reactor is used, the hydrothermal pyrolysis of soapstock is carried out in the first-stage reactor, and the catalytic hydrodeoxygenation reaction of pyrolysis volatile product is carried out in the second-stage reactor, and finally liquid fuel is obtained; the hydrodeoxygenation catalyst is 10% Ni / LaCoO3; the set temperature of the first-stage reactor is 550 DEG C, the set temperature of the second-stage reactor is 300 DEG C, and the pressure is 2.5 bar; the soapstock is one or more of coconut oil, peanut oil, palm oil, rapeseed oil, soybean oil or peony seed oil soapstock; the method comprises the following steps: (1) the hydrodeoxygenation catalyst is loaded into the quartz tube, and the quartz tube is loaded into the second-stage reactor; the soapstock is loaded into the sample bottle, and the sample bottle is loaded into the sample inlet; the carrier gas, the reaction gas and the reaction device are communicated, the carrier gas is blown through the sample loading position to purge the first-stage reactor and the second-stage reactor in the serial two-stage reactor for 3-7 min; (2) switch to continue purging the first-stage reactor and the second-stage reactor in the serial two-stage reactor for 10-15 min, set the reaction temperature and pressure of the first-stage reactor and the second-stage reactor, and start heating to heat the first-stage reactor and the second-stage reactor; (3) when the temperature and pressure of the reactor reach the set value, the sample bottle loaded with soapstock is sent into the first-stage reactor for hydrothermal pyrolysis, the pyrolysis volatile product enters the second-stage reactor for catalytic hydrodeoxygenation reaction with the reaction gas, and finally liquid fuel is obtained.

2. The process for the production of liquid fuels by two-stage hydroprocessing of soapstock according to claim 1, characterized in that, The carrier gas is helium or hydrogen, and the reaction gas is hydrogen; the flow rate of the reaction gas or the carrier gas is 70-160 mL / min.

3. The process for the production of liquid fuels by two-stage hydroprocessing of soapstock according to claim 1, characterized in that, The mass ratio of soapstock to hydrodeoxygenation catalyst is 3:5-1:4.

Images