Method for preparing biological aviation kerosene by hydrogenation of waste oil

Abstract

The invention discloses a method for preparing biological aviation kerosene by hydrogenation of waste grease, which comprises the following steps: mixing pretreated waste grease and coal tar to form mixed raw oil, reacting under the continuous action of a catalyst I and a catalyst II to obtain generated oil, and introducing the generated oil into a high-pressure separator for separation to obtain the biological aviation kerosene. And carrying out high-pressure steam stripping on the separated product, passing the stripped product oil through a hydroisomerization reaction unit, and then carrying out normal-pressure fractionation to obtain the biological aviation kerosene. According to the preparation method, firstly, raw materials are improved, pretreated waste grease is adopted, the reaction efficiency can be improved through the pretreated waste grease, in the process that H2S iO3 is adopted for modifying Cu / gamma-Al2O3, and H2S iO3 auxiliaries and active components are introduced, high-temperature roasting can cause damage to a lamellar structure on the surface of a gamma-A2O3 carrier, and in the process, high-temperature roasting can cause damage to the surface of the gamma-A2O3 carrier; the adjacent pore structures of the carrier material are combined to form a larger pore diameter, and part of the pore structures of the catalyst can be filled, so that the conversion efficiency is increased.

Description

Technical Field

[0001] The invention belongs to the technical field of waste oil and grease processing, and specifically relates to a method for preparing bio-jet fuel by hydrogenating waste oil and grease. Background Art

[0002] At present, my country's national consumption level is gradually increasing, and the amount of waste animal and plant oils generated by the increasingly prosperous catering industry is rising year by year. For the sake of people's food safety, the country has further increased its control efforts to prevent the phenomenon of waste oils returning to the table. As a zero-carbon energy source, biomass energy will play an important role, and its energy industry will also usher in a major development opportunity period, and the rational use of waste animal and plant oils is of great significance. To this end, in response to policies and the concept of healthy and environmentally friendly development, we have developed this process, whose products are alkylated biomass aviation fuel, biodiesel and biomass naphtha, and the raw materials are waste animal and plant oils. This type of product has a positive significance for reducing carbon emissions, and the mandatory policies of some EU countries have increased the proportion of biomass aviation fuel added to aviation kerosene, which has good policy incentives and broad market prospects.

[0003] Biojet fuel is made from waste animal and plant oils and fats. It undergoes chemical treatments such as hydrodeoxygenation, cracking, and isomerization to separate hydrocarbon components with a composition of C9 to C16. It can be provided to jet aircraft directly or mixed with traditional jet fuel. Compared with traditional jet fuel, biojet fuel can reduce carbon dioxide emissions by 55%-92%, effectively solving the environmental and energy problems of the civil aviation industry. It is not only renewable and sustainable, but also does not require engine modification and has high environmental advantages. The development of biojet fuel has received widespread attention in many countries around the world.

[0004] The publication number CN111909720A also discloses a technical route for long-term synthesis: "waste animal and vegetable oils and fats → hydrorefining → high and low pressure separation → stripping → isomerization → high and low pressure separation → fractionation". The catalyst used is an active component of two or three of nickel metal salt, molybdenum metal salt, cobalt metal salt, and tungsten metal salt; the catalyst carrier is a modified molecular sieve-alumina.

[0005] Most of the existing process flows still use a single oil as a raw material for production, which has low production efficiency and conversion rate, and also generally uses traditional catalysts, such as the spherical Ni-MO / Al2O3 catalyst used in the above patents, and the spherical Ni-MO / Al2O3 catalyst used in patent 202311247216.3, and the carbon-based material used as the carrier active component in patent 202211376662.X is at least one of oxidized nickel, molybdenum, and cobalt. However, the conversion rate of the above catalysts is not high and is not suitable for industrial production. Summary of the invention

[0006] The purpose of the present invention is to provide a method for preparing bio-jet fuel by hydrogenating waste oils and fats, so as to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for preparing bio-jet fuel by hydrogenating waste oil, comprising the following steps:

[0008] S1: mixing the pretreated waste oil and coal tar to form a mixed raw oil;

[0009] S2: Under light conditions, the mixed raw material oil and the treated catalyst 1 are introduced into a reactor 1, the reaction temperature is set to 110-130°C, the stirring speed is set to 800-1200r / min, hydrogen is introduced into the reactor 1 through a booster pump to make the hydrogen pressure 0.3-0.5MPa, and the reaction is carried out for 10-14h;

[0010] S3: introducing the product after the above reaction and the second catalyst into the second reactor, setting the reaction temperature to 300-500° C., introducing hydrogen into the second reactor through a booster pump to make the hydrogen pressure 1.0-3.0 MPa, and reacting to obtain a product oil;

[0011] S4: passing the generated oil into a high-pressure separator for separation, and performing high-pressure stripping on the separated product to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, and ammonia therein to obtain product oil;

[0012] S5: The product oil after stripping is passed through a hydroisomerization reaction unit and then subjected to atmospheric pressure fractionation to produce bio-jet fuel.

[0013] Preferably, the waste oil includes at least one of acidified oil, industrial palm oil, palm oil production wastewater, sewage oil, animal fat, and waste materials from oil processing plants.

[0014] Preferably, in any of the above schemes, in step S1, the concentration of the waste oil is 30-50 g / 100 mL.

[0015] Preferably, in any of the above schemes, in step S1, the pretreatment process of the waste grease is: adding 2-4% ethanolamine by weight of the waste grease, adding 1-2% deionized water by weight of the waste grease and mixing with the waste grease, reacting for 30-60 minutes at a stirring speed of 200-300 r / min and a temperature of 50-70°C, and finally obtaining the pretreated waste grease through centrifugal separation and dehydration and drying.

[0016] In any of the above schemes, preferably, in step S2, the catalyst 1 is Pt—TiO2.

[0017] Preferably, in any of the above schemes, in step S2, the step of treating the catalyst 1 is: using dichloromethane to clean the interior and pipelines of the reactor, then loading the catalyst 1 into the reactor, passing 0.3-0.5MPa argon gas for purging until the air is exhausted, and then adjusting the temperature to 200-400°C, the hydrogen pressure to 0.5-1.5MPa, and treating for 2-4h.

[0018] In any of the above schemes, preferably, in step S2, there are multiple reactors one, and they are arranged in parallel, and the outlets of the multiple reactors one are connected to the inlet of the reactor two.

[0019] In any of the above schemes, preferably, in step S3, the catalyst 2 is a H2S iO3 modified Cu / γ-Al2O3 catalyst.

[0020] Preferably, in any of the above schemes, the preparation method of the H2S iO3 modified Cu / γ-Al2O3 catalyst comprises adding 0.5-1.5% H2S iO3 reagent by mass to deionized water, adding γ-Al2O3 carrier after mixing evenly, and impregnating at room temperature for 20-30 hours, then placing the beaker in a water bath on a shaker at 50-80°C to evaporate to dryness, and then placing it in a constant temperature oven at 90-120°C to dry overnight, and the dried sample is calcined in a muffle furnace at 380-520°C for 3.0-5.0 hours to obtain H2S iO3 catalyst. 3- γ-Al2O3 modified carrier, and then prepare the precursor with metal Cu loading of 4-6wt%. The specific preparation process is as follows: 3- The γ-Al2O3 modified carrier was impregnated in an aqueous solution of Cu(NO3)2·3H2O (the Cu loading was 4-6wt%), and after being evaporated on a shaking table and dried in an oven overnight, it was calcined in an air atmosphere at 400°C in a muffle furnace for 4.0h to obtain a H2SiO3 modified Cu / γ-Al2O3 precursor with a Cu loading of 4-6wt%. The prepared precursor was reduced at 300-400°C in a H2 atmosphere for 2h to obtain a H2SiO3 modified Cu / γ-Al2O3 catalyst.

[0021] A bio-jet fuel produced by a method for producing bio-jet fuel by hydrogenating waste oils and fats.

[0022] The technical effects and advantages of the present invention are as follows: the method for preparing bio-jet fuel by hydrogenating waste oil firstly improves the raw materials, adopts pretreated waste oil, and the reaction efficiency can be improved by the pretreated waste oil, and the pretreated waste oil is mixed with low-temperature (360°C) coal tar to form a mixed raw material. When the addition ratio of the pretreated waste oil is 40g / 100mL, the conversion rate of fatty acids is 96.22%, which is 7.9% higher than that of the single biomass oil hydrogenation deoxygenation. In the first stage, a Pt-TiO2 catalyst is used. Under the condition of light, triglycerides are converted into saturated and unsaturated fatty acids, and unsaturated fatty acids are hydrogenated into saturated fatty acids. TiO2 absorbs photons, generates electron transitions to generate carriers, and saturated fatty acids undergo oxidation reactions with photogenerated holes to generate Cn-1 alkyl radicals, carbon dioxide and carboxyl protons. The Cn-1 alkyl radicals combine with hydrogen on the surface of TiO2 to generate Cn-1 alkanes, thereby improving the conversion rate. Finally, H2S is used on the catalyst two. In the process of modifying Cu / γ-Al2O3 with iO3 and introducing H2SiO3 additives and active components, high-temperature calcination will cause the lamellar structure on the surface of the γ-A2O3 carrier to be destroyed, so that the adjacent pore structures of the carrier material will merge to form a larger pore size, and will fill part of the pore structure of the catalyst. In addition, a large amount of additives is not conducive to the monolayer loading of the additives on the γ-A2O3 carrier, causing blockage in the pore structure of the corresponding Cu / γ-Al2O3 catalyst, thereby significantly reducing the specific surface area and pore volume of the catalyst, thereby increasing the conversion efficiency. DETAILED DESCRIPTION

[0023] The following will be described clearly and completely in conjunction with the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] The catalyst used in the embodiment of the present invention is Pt-TiO2, and the doping amount of Pt is 1%. The metal is loaded by the equal volume impregnation method. First, titanium dioxide and Pt(NO3)3 powder are added with appropriate amount of water until just saturated. The mass ratio of titanium dioxide to Pt is 20:1. After fully mixing, they are placed for 12 hours, and then placed in an electric heated blast drying oven at 85°C for 6 hours. After cooling to room temperature, they are placed in a muffle furnace at 400°C for calcination for 4 hours. After cooling to room temperature, they are ground into powder and sieved to obtain a metal-doped photocatalyst.

[0025] However, the present invention treats the catalyst before use, and the treatment steps are: use dichloromethane to clean the interior and pipelines of the reactor, then load the catalyst into the reactor, pass 0.4MPa argon gas for purging until the air is exhausted, and then adjust the temperature to 300°C, the hydrogen pressure to 1MPa, and treat for 3h.

[0026] The catalyst used in the embodiment of the present invention is a H2S iO3 modified Cu / γ-Al2O3 catalyst, which is prepared by adding 1.0% H2S iO3 reagent by mass to deionized water, mixing well, adding γ-Al2O3 carrier, and impregnating at room temperature for 30 hours. Then, the beaker is placed on a shaking table at 60°C for water bath evaporation, and then placed in a constant temperature oven at 100°C for overnight drying. The dried sample is calcined in a muffle furnace at 400°C for 4.0 hours to obtain H2S iO3. 3- γ-Al2O3 modified support, and then prepare a precursor with a metal Cu loading of 5wt% according to the above steps. The specific preparation process is to obtain H2S iO 3- The γ-Al2O3 modified carrier was impregnated in an aqueous solution of Cu(NO3)2·3H2O (Cu loading was 4-6wt%), and after being evaporated on a shaking table and dried in an oven overnight, it was calcined in an air atmosphere at 400°C in a muffle furnace for 4.0h to obtain a H2SiO3 modified Cu / γ-Al2O3 precursor with a Cu loading of 4-6wt%. The prepared precursor was reduced at 350°C in a H2 atmosphere for 2h to obtain a H2SiO3 modified Cu / γ-Al2O3 catalyst.

[0027] The waste grease used in the embodiment of the present invention includes at least one of acidified oil, industrial palm oil, palm oil production wastewater, slop oil, animal fat, and waste materials from a grease processing plant, and is pretreated before use. The pretreatment method comprises adding 2% ethanolamine by weight of the waste grease, adding 1% deionized water by weight of the waste grease and mixing with the waste grease, reacting for 30 minutes at a stirring speed of 300 r / min and a temperature of 60°C, and finally centrifuging and dehydrating and drying to obtain the pretreated waste grease.

[0028] Embodiment 1:

[0029] Catalyst 1 and Catalyst 2 in this embodiment are both prepared by the above method, and the treatment process is also recorded above.

[0030] A method for preparing bio-jet fuel by hydrogenating waste oils and fats, comprising the following steps:

[0031] S1: Mixing the pretreated waste grease with coal tar to form a mixed raw material, wherein the concentration of the waste grease is 40 g / 100 mL;

[0032] S2: Under light conditions, the mixed raw material oil and the treated catalyst one are introduced into a reactor one, the reaction temperature is set to 120°C, the stirring speed is 1000r / min, hydrogen is introduced into the reactor one through a booster pump to make the hydrogen pressure 0.4MPa, and the reaction is carried out for 12h. Three reactors one can be set, and the three reactors one are set in parallel;

[0033] S3: introducing the product after the above reaction and the catalyst 2 into the reactor 2, setting the reaction temperature to 400°C, introducing hydrogen into the reactor 2 through a booster pump to make the hydrogen pressure to be 2.0 MPa, and obtaining the generated oil by the reaction, and the outlets of the three reactors 1 are connected to the inlet of the reactor 2;

[0034] S4: passing the above generated oil into a high-pressure separator for separation, and separating gas, product oil and water under a pressure of 4 MPa. The separated product is subjected to high-pressure stripping at 260-360° C. and a pressure of 2.5-3.5 MPa to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, ammonia and other substances therein;

[0035] S5: The product oil after stripping is passed through a hydroisomerization reaction unit. The structure and function of the hydroisomerization reaction unit refer to CN117229804A. The reaction temperature is 320-350°C, the reaction pressure is 5-15Mpa, and the hydrogen-oil volume ratio is (800-1500):1. After the reaction, it is fractionated at 380°C under normal pressure to extract the aviation kerosene component of 160-270°C and the biodiesel component of 270-320°C, respectively, to obtain bio-jet kerosene.

[0036] Embodiment 2:

[0037] A method for preparing bio-jet fuel by hydrogenating waste oils and fats, comprising the following steps:

[0038] S1: Mixing the pretreated waste oil and coal tar to form a mixed raw oil, wherein the concentration of the waste oil is 40g / 100mL;

[0039] S2: Under light conditions, the mixed raw material oil and the treated catalyst 1 are introduced into a reactor 1, the reaction temperature is set to 110°C, the stirring speed is 800r / min, hydrogen is introduced into the reactor 1 through a booster pump to make the hydrogen pressure 0.3MPa, and the reaction is carried out for 10h;

[0040] S3: introducing the product after the above reaction and the second catalyst into the second reactor, setting the reaction temperature to 300° C., introducing hydrogen into the second reactor through a booster pump to make the hydrogen pressure to be 1.0 MPa, and reacting to obtain a product oil;

[0041] S4: passing the generated oil into a high-pressure separator for separation at a pressure of 6 MPa to obtain gas, product oil and water, and performing high-pressure stripping on the separated product to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, ammonia and other substances therein to obtain product oil;

[0042] S5: The product oil after stripping is passed through a hydroisomerization reaction unit and then subjected to atmospheric pressure fractionation to produce bio-jet fuel.

[0043] Embodiment 3:

[0044] A method for preparing bio-jet fuel by hydrogenating waste oils and fats, comprising the following steps:

[0045] S1: mixing the pretreated waste oil and coal tar to form a mixed raw oil;

[0046] S2: Under light conditions, the mixed raw material oil and the treated catalyst 1 are introduced into a reactor 1, the reaction temperature is set to 130°C, the stirring speed is set to 1200r / min, hydrogen is introduced into the reactor 1 through a booster pump to make the hydrogen pressure 0.5MPa, and the reaction is carried out for 14h;

[0047] S3: introducing the product after the above reaction and the second catalyst into the second reactor, setting the reaction temperature to 500° C., introducing hydrogen into the second reactor through a booster pump to make the hydrogen pressure 3.0 MPa, and reacting to obtain a product oil;

[0048] S4: passing the generated oil into a high-pressure separator for separation at a pressure of 8 MPa to obtain gas, product oil and water, and performing high-pressure stripping on the separated product to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide and ammonia to obtain product oil;

[0049] S5: The product oil after stripping is passed through a hydroisomerization reaction unit and then subjected to atmospheric pressure fractionation to produce bio-jet fuel.

[0050] Comparative Example 1:

[0051] Catalyst 1 and Catalyst 2 in this comparative example are both prepared by the above method, and the treatment process is also as described above. The only difference from Example 1 is that in step S2, no light treatment is used.

[0052] Specifically, a method for preparing bio-jet fuel by hydrogenating waste oils and fats comprises the following steps:

[0053] S1: Mixing the pretreated waste grease with low-temperature (360°C) coal tar to form a mixed raw material, wherein the concentration of the waste grease is 40g / 100mL;

[0054] S2: introducing the mixed raw material oil and the treated catalyst 1 into a reactor 1, setting the reaction temperature to 120°C and the stirring speed to 1000 r / min, introducing hydrogen into the reactor 1 through a booster pump to make the hydrogen pressure to be 0.4 MPa, and reacting for 12 hours. Multiple reactors 1 can be set, for example, 3, according to actual production, and multiple reactors 1 are set in parallel;

[0055] S3: introducing the product after the above reaction and the second catalyst into the second reactor, setting the reaction temperature to 400° C., introducing hydrogen into the second reactor through a booster pump to make the hydrogen pressure to be 2.0 MPa, and obtaining the product oil by reaction, and the outlets of the first reactors are all connected to the inlet of the second reactor;

[0056] S4: passing the above generated oil into a high-pressure separator for separation, and subjecting the separated product to high-pressure stripping at a pressure of 4 MPa to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, ammonia and other substances therein to obtain product oil;

[0057] S5: The product oil after stripping is passed through a hydroisomerization reaction unit and then subjected to atmospheric pressure fractionation to produce bio-jet fuel.

[0058] Experiments were conducted on the preparation of bio-jet fuel in Examples 1, 2, 3 and Comparative Example 1. The qualitative analysis of the liquid product was obtained by GC-MS analysis. The relative percentage content of each indicator obtained by the qualitative analysis was calculated using the "area normalization method" to obtain the quantitative statistics of the composition of the liquid product. The results of the experiment are shown in Table 1 below: The calculation formula for the conversion rate in the table is as follows:

[0059] X%=[M(T0)-M(T1)] / M(T0)×100%,

[0060] Wherein, M(T0) is the mass percentage of waste oil pretreated before the reaction, and M(T1) is the mass percentage of waste oil after the reaction is completed;

[0061] The selectivity of alkanes is calculated as follows:

[0062] Y%=∑M(X) / [M(T0)-M(T1)]×100%,

[0063] Wherein, M(X) is the sum of the mass percentages of all alkanes in the liquid phase product after the reaction is completed;

[0064] The selectivity calculation formula for C8-C17 alkanes is as follows:

[0065] Z%=∑M(X0) / [M(T0)-M(T1)]×100%,

[0066] Wherein, M(X0) is the sum of the mass percentages of C8-C17 alkanes in the liquid phase product after the reaction is completed.

[0067] Table 1

[0068]

[0069] As can be seen from Table 1, the conversion rate, alkane selectivity and C8-C 17 The selectivity of alkanes has been greatly improved.

[0070] Comparative Example 2:

[0071] Catalyst 1 and Catalyst 2 in this comparative example are both prepared by the above method, and the treatment process is also as described above. The only difference from Example 1 is that in step S1, the raw material is only pre-treated waste oil.

[0072] Specifically: a method for preparing bio-jet fuel by hydrogenating waste oil, comprising the following steps:

[0073] S1: Mixing the pretreated waste oil to form a mixed raw material, wherein the concentration of the waste oil is 40g / 100mL;

[0074] S2: Under light conditions, the mixed raw material oil and the treated catalyst one are introduced into a reactor one, the reaction temperature is set to 120°C, the stirring speed is 1000r / min, hydrogen is introduced into the reactor one through a booster pump to make the hydrogen pressure 0.4MPa, and the reaction is carried out for 12h. Multiple reactors one can be set, for example, 3, which are selected according to actual production, and multiple reactors one are set in parallel;

[0075] S3: introducing the product after the above reaction and the second catalyst into the second reactor, setting the reaction temperature to 400° C., introducing hydrogen into the second reactor through a booster pump to make the hydrogen pressure to be 2.0 MPa, and obtaining the product oil by reaction, and the outlets of the first reactors are all connected to the inlet of the second reactor;

[0076] S4: passing the above generated oil into a high-pressure separator for separation, and subjecting the separated product to high-pressure stripping at a pressure of 4 MPa to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, ammonia and other substances therein to obtain product oil;

[0077] S5: The product oil after stripping is passed through a hydroisomerization reaction unit and then subjected to atmospheric pressure fractionation to produce bio-jet fuel.

[0078] Experiments were conducted on the preparation of bio-jet fuel in Examples 1, 2, 3 and Comparative Example 2. The results of the experiments are shown in Table 2 below:

[0079] Table 2

[0080]

[0081] It can be seen that after the pretreated waste oil is mixed with low-temperature (360℃) coal tar to form a mixed raw material, the fatty acid conversion rate is greatly improved, indicating that some or all of the saturated aromatic hydrocarbons in the product are dehydrogenated, realizing the conversion of gas-phase hydrogen to adsorbed active hydrogen, and promoting the hydrogenation and deoxygenation of fatty acids.

[0082] Comparative Example 3:

[0083] Catalyst 1 in this comparative example is prepared by the above method, and the processing flow is also as described above. The only difference from Example 1 is Catalyst 2. Catalyst 2 in this comparative example uses Cu / γ-Al2O3 catalyst.

[0084] Specifically, a method for preparing bio-jet fuel by hydrogenating waste oils and fats comprises the following steps:

[0085] S1: Mixing the pretreated waste grease with low-temperature (360°C) coal tar to form a mixed raw material, wherein the concentration of the waste grease is 40g / 100mL;

[0086] S2: Under light conditions, the mixed raw material oil and the treated catalyst one are introduced into a reactor one, the reaction temperature is set to 120°C, the stirring speed is 1000r / min, hydrogen is introduced into the reactor one through a booster pump to make the hydrogen pressure 0.4MPa, and the reaction is carried out for 12h. Multiple reactors one can be set, for example, 3, which are selected according to actual production, and multiple reactors one are set in parallel;

[0087] S3: introducing the product after the above reaction and the Cu / γ-Al2O3 catalyst into the reactor 2, setting the reaction temperature to 400°C, introducing hydrogen into the reactor 2 through a booster pump to make the hydrogen pressure 2.0MPa, and obtaining the generated oil, and the outlets of the multiple reactors 1 are connected to the inlet of the reactor 2;

[0088] S4: passing the above generated oil into a high-pressure separator for separation, and separating gas, product oil and water under a pressure of 4 MPa, and performing high-pressure stripping on the separated product to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, ammonia and other substances therein;

[0089] S5: The product oil after stripping is passed through a hydroisomerization reaction unit and then subjected to atmospheric pressure fractionation to produce bio-jet fuel.

[0090] Experiments were conducted on the preparation of bio-jet fuel in Examples 1, 2, 3 and Comparative Example 3. The results of the experiments are shown in Table 3 below:

[0091] Table 3

[0092]

[0093]

[0094] It can be seen that the average pore size of Cu / γ-Al2O3 modified with H2SiO3 is significantly increased. The introduction of H2SiO3 additive can effectively regulate the pore structure of each catalyst. The Cu / γ-Al2O3 catalyst prepared with low H2SiO3 additive introduction exhibits a good mesoporous structure, which is conducive to the uniform dispersion of metal Cu species and provides a good pore structure foundation for the formation of catalytic active centers. Similarly, its conversion rate is also significantly improved.

[0095] The present invention also provides a preparation method of H2S iO3 modified Cu / γ-Al2O3 catalyst, which comprises adding 0.5% H2S iO3 reagent by mass into deionized water, mixing evenly, adding γ-Al2O3 carrier, and impregnating at room temperature for 20 hours, then placing the beaker on a shaking table at 50°C in a water bath for evaporation, and then placing the beaker in a constant temperature oven at 90°C for overnight drying, and calcining the dried sample in a muffle furnace at 380°C for 3.0 hours to obtain H2S iO3 modified Cu / γ-Al2O3 catalyst. 3- The γ-Al2O3-modified carrier was then prepared according to the above steps with a precursor having a metal Cu loading of 4 wt%, and reduced at 300°C for 2 h under a H2 atmosphere to obtain a H2SiO3-modified Cu / γ-Al2O3 catalyst.

[0096] The preparation method of H2S i O3 modified Cu / γ-Al2O3 catalyst is as follows: add 1.5% H2S iO3 reagent by mass into deionized water, mix well and add γ-Al2O3 carrier, soak at room temperature for 30 hours, then place the beaker on a shaking table at 80°C in a water bath to evaporate to dryness, then place in a constant temperature oven at 120°C to dry overnight, and the dried sample is calcined in a muffle furnace at 520°C for 5.0 hours to obtain H2S i O3 modified Cu / γ-Al2O3 catalyst. 3- The γ-Al2O3-modified carrier was then prepared according to the above steps with a precursor having a metal Cu loading of 6 wt%, and the catalyst was reduced at 400 °C for 2 h under a H2 atmosphere to obtain a H2SiO3-modified Cu / γ-Al2O3 catalyst.

[0097] The above two methods for preparing H2SiO3 modified Cu / γ-Al2O3 catalysts have the same effects as those in the examples and can be selected for use in actual production.

[0098] The present invention also provides two methods for pretreating waste grease, one of which is to add ethanolamine at 2% by weight of the waste grease, add deionized water at 2% by weight of the waste grease and mix with the waste grease, react for 30 minutes at a stirring speed of 200 r / min and a temperature of 50°C, and finally obtain the pretreated waste grease through centrifugal separation and dehydration and drying.

[0099] The second method is to add 4% ethanolamine by weight of the waste oil, add 2% deionized water by weight of the waste oil and mix with the waste oil, react for 60 minutes at a stirring speed of 300r / min and a temperature of 70°C, and finally obtain the pretreated waste oil through centrifugal separation and dehydration and drying.

[0100] The above two processing methods are also the same as those in the embodiment, and which method to adopt can be selected according to actual use.

[0101] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing bio-jet fuel by hydrogenating waste oils, characterized in that: The following steps are involved: S1: mixing the pretreated waste oil and coal tar to form a mixed raw oil; S2: Under light conditions, the mixed raw material oil and the treated catalyst 1 are introduced into a reactor 1, the reaction temperature is set to 110-130°C, the stirring speed is set to 800-1200r / min, hydrogen is introduced into the reactor 1 through a booster pump to make the hydrogen pressure 0.3-0.5MPa, and the reaction is carried out for 10-14h; S3: introducing the product after the above reaction and the second catalyst into the second reactor, setting the reaction temperature to 300-500° C., introducing hydrogen into the second reactor through a booster pump to make the hydrogen pressure 1.0-3.0 MPa, and reacting to obtain a product oil; S4: passing the generated oil into a high-pressure separator for separation, and performing high-pressure stripping on the separated product to remove short-chain hydrocarbons, hydrogen, dry gas, liquefied gas, water vapor, hydrogen sulfide, and ammonia therein to obtain product oil; S5: The product oil after stripping is passed through a hydroisomerization reaction unit and then subjected to atmospheric pressure fractionation to produce bio-jet fuel.

2. The method for preparing bio-jet fuel by hydrogenating waste oil according to claim 1, characterized in that: The waste oil and fat includes at least one of acidified oil, industrial palm oil, palm oil production wastewater, sewage oil, animal fat, and waste materials from oil and fat processing plants.

3. The method for preparing bio-jet fuel by hydrogenating waste oil according to claim 2, characterized in that: In step S1, the concentration of the waste oil is 30-50 g / 100 mL.

4. The method for preparing bio-jet fuel by hydrogenating waste oil according to claim 3, characterized in that: In step S1, the pretreatment process of the waste grease is as follows: adding 2-4% ethanolamine by weight of the waste grease, adding 1-2% deionized water by weight of the waste grease and mixing with the waste grease, reacting for 30-60 minutes at a stirring speed of 200-300 r / min and a temperature of 50-70°C, and finally obtaining the pretreated waste grease through centrifugal separation and dehydration and drying.

5. The method for preparing bio-jet fuel by hydrogenating waste oil according to claim 1, characterized in that: In step S2, the catalyst 1 is Pt-TiO2.

6. The method for preparing bio-jet fuel by hydrogenating waste oil according to claim 5, characterized in that: In step S2, the steps of treating the catalyst 1 are: using dichloromethane to clean the interior and pipelines of the reactor, then loading the catalyst 1 into the reactor, passing 0.3-0.5MPa argon gas for purging until the air is exhausted, and then adjusting the temperature to 200-400°C, the hydrogen pressure to 0.5-1.5MPa, and treating for 2-4h.

7. The method for preparing bio-jet fuel by hydrogenating waste oil according to claim 1, characterized in that: In step S2, the reactor one is provided in plurality and arranged in parallel, and the outlets of the plurality of reactors one are all connected to the inlet of the reactor two.

8. The method for preparing bio-jet fuel by hydrogenating waste oils according to claim 1, characterized in that: In step S3, the catalyst 2 is a H2SiO3 modified Cu / γ-Al2O3 catalyst.

9. The method for preparing bio-jet fuel by hydrogenating waste oils according to claim 8, characterized in that: The preparation method of the H2SiO3 modified Cu / γ-Al2O3 catalyst comprises the following steps: adding 0.5-1.5% H2SiO3 reagent by mass into deionized water, mixing evenly, adding γ-Al2O3 carrier, and impregnating at room temperature for 20-30 hours; then, placing the beaker in a water bath on a shaker at 50-80°C to evaporate to dryness; and then placing the beaker in a constant temperature oven at 90-120°C to dry overnight; and calcining the dried sample in a muffle furnace at 380-520°C for 3.0-5.0 hours to obtain H2SiO3. 3- The γ-Al2O3 modified carrier is then prepared, and a precursor with a metal Cu loading of 4-6wt% is prepared. The prepared precursor is reduced at 300-400°C for 2h in a H2 atmosphere to obtain a H2SiO3 modified Cu / γ-Al2O3 catalyst.

10. Bio-jet fuel prepared according to the preparation method according to any one of claims 1 to 9.

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