Hydrogenation method of waste grease

Abstract

The invention relates to a hydrogenation method of waste oil and fat, which comprises the following steps of: contacting the waste oil and fat with a hydrotreating catalyst in a hydrotreating reaction zone to react, cutting the obtained liquid hydrocarbon to obtain a liquid hydrocarbon light component and a liquid hydrocarbon heavy component, respectively feeding the liquid hydrocarbon light component and the liquid hydrocarbon heavy component into a first hydroisomerization reaction zone and a second hydroisomerization reaction zone to react, and separating the obtained reaction effluent to obtain the waste oil and fat. The biological naphtha, the biodiesel and the biological lubricating oil base oil are obtained. According to the method, the biodiesel and the bio-based lubricant base oil are simultaneously produced by using the waste grease raw material, the waste grease raw material is completely converted, and the yield of the target product is high.

Description

Technical Field

[0001] The present invention relates to a hydrogenation method for waste oils and fats, and specifically, to a hydrogenation method for producing biodiesel and base oil of bio-lubricant from waste oils and fats. Background Art

[0002] With the tightening of the supply of traditional fossil energy and the increasing pressure of carbon dioxide emission reduction, how to effectively reduce the carbon dioxide gas emissions while increasing the fuel supply is an important problem faced by the refining industry. Biodiesel fuel prepared from renewable biomass such as animal and vegetable oils or agricultural and forestry wastes has significantly lower greenhouse gas emissions in its whole life cycle than fossil diesel fuel, and the development of biomass fuel is considered to be one of the effective means to solve this problem.

[0003] The reasons why biofuels have gradually attracted people's attention are mainly as follows: 1. Biofuels are renewable energy sources; 2. The carbon-containing characteristics of biofuels are close to those of existing fuels; 3. The carbon dioxide absorbed by the precursors of biofuels can reduce the net emissions of greenhouse gases; 4. Bioenergy is more evenly distributed than fossil energy.

[0004] Vegetable oil is the most easily available biofuel, mainly composed of triglycerides and a small amount of free fatty acids. The use of vegetable oil in diesel engines can be traced back to 1900, and Rudolf Diesel confirmed the operation ability of peanut oil in diesel engines. During World War II, palm oil and peanut oil were used as fuels for military vehicles in Africa. After the war, the development of technology led to almost the only raw material being fuels derived from petroleum. In particular, the injector and control system of diesel engines have been greatly improved, resulting in a very single source of diesel engine raw materials. At the same time, the high viscosity, poor stability of pure vegetable oil, and the high cost of vegetable oil limit its application as a transportation fuel directly.

[0005] The traditional method for converting vegetable oil or other fatty acid derivatives into liquid fuel is transesterification. The transesterification method is an ester exchange reaction using alcohol under the action of a catalyst, which converts the triglycerides forming vegetable oil into corresponding fatty acid alkyl esters, usually fatty acid methyl esters. However, the low-temperature fluidity of fatty acid methyl esters limits their use in low-temperature environments. The low-temperature fluidity of fatty acid methyl esters is determined by the chain characteristics of their fatty acids. The presence of carbon-carbon double bonds can improve the low-temperature fluidity, but reduces the stability of fatty acid methyl esters. Since the presence of oxygen in fatty acid methyl esters will result in higher NOx emissions compared to traditional diesel fuels.

[0006] Grease can produce diesel components through hydrogenation technology, but the resulting product is n-alkanes with a relatively high freezing point and poor low-temperature fluidity. To improve the low-temperature flow performance of the hydrogenation product, the usual method is to carry out an isomerization reaction on the product. A raw material selected from vegetable oil, animal oil or fish oil is subjected to a hydrodeoxygenation step, followed by a hydroisomerization step.

[0007] In the prior art, the preparation of hydroisomerization catalysts usually involves an ammonium exchange after crystallization and then an extrusion molding method. However, the alkali metal content in the obtained catalysts is generally below 0.1 wt%, which is difficult to further reduce, resulting in limited catalytic activity of the catalysts. Therefore, how to further improve the catalytic activity of hydroisomerization catalysts is also an important problem existing in the prior art. Summary of the Invention

[0008] The object of the present invention is to provide a hydrogenation method for waste grease on the basis of the prior art to solve the problem of low utilization rate of waste grease in the prior art.

[0009] The hydrogenation method for waste grease provided by the present invention includes:

[0010] (1) Waste grease and hydrogen enter the hydrotreating reaction zone together and react with a hydrotreating catalyst under hydrotreating reaction conditions to obtain a hydrotreating reaction effluent. The active metal component of the hydrotreating catalyst is at least one metal component selected from Group VIII and / or at least one metal component selected from Group VIB.

[0011] The obtained hydrotreating reaction effluent is separated to obtain a liquid hydrocarbon, water and a gas stream. The liquid hydrocarbon is cut to obtain a light liquid hydrocarbon fraction and a heavy liquid hydrocarbon fraction, and the cutting point is 360 - 370 °C.

[0012] (2) The light liquid hydrocarbon fraction obtained in step (1) enters the first hydroisomerization reaction zone and reacts with a hydroisomerization catalyst under the first hydroisomerization reaction conditions to obtain a first hydroisomerization reaction effluent.

[0013] (3) The heavy liquid hydrocarbon fraction obtained in step (1) enters the second hydroisomerization reaction zone and reacts with a hydroisomerization catalyst under the second hydroisomerization reaction conditions to obtain a second hydroisomerization reaction effluent.

[0014] The first hydroisomerization reaction effluent and the second hydroisomerization reaction effluent are subjected to gas-liquid separation and liquid-phase fractionation to obtain bio-naphtha, biodiesel and a bio-lubricating oil base oil.

[0015] In steps (2) and (3), the hydroisomerization catalyst includes a carrier and an active metal component supported on the carrier. The carrier contains ZSM-48 molecular sieve. The molar ratio of silica to alumina in the ZSM-48 molecular sieve is not less than 40. The specific surface area of the ZSM-48 molecular sieve is not less than 200 m2 / g. The crystal grains of the ZSM-48 molecular sieve are ellipsoidal, with the major axis not exceeding 700 nm and the major axis to minor axis ratio being 1 - 3:1;

[0016] The active metal component is Pt and / or Pd;

[0017] In the hydroisomerization catalyst, based on the total amount of the hydroisomerization catalyst, the content of the molecular sieve on a dry basis is 20 - 80% by weight, and based on elements, the content of the active metal component is 0.1 - 20% by weight;

[0018] Among them, based on the total amount of the carrier, the content of the basic metal oxide in the carrier is not higher than 0.001% by weight.

[0019] In the present invention, the unsaponifiable matter content in the waste oil ≥ 2% by weight. The waste oil is the oil waste that is not suitable for further consumption generated in the processing of animal and vegetable oils and edible consumption. It includes fatty acids, acidified oil, etc. generated during the production of edible oil from oilseeds; various catering waste oils such as frying waste oil, kitchen waste oil, swill oil, etc. generated from the edible oil used by households, hotels, the catering industry, and food production enterprises; animal fats by-produced in the production and processing of meat, and also edible oil beyond the shelf life, etc.

[0020] In one embodiment of the present invention, the hydrotreating reaction conditions are: reaction temperature 250 - 450 °C, reaction pressure 3.0 - 10.0 MPa, volume space velocity 0.1 - 10.0 h -1 , hydrogen-to-oil volume ratio 300 - 2000 Nm 3 / m 3 ;

[0021] Preferably, the hydrotreating reaction conditions are: reaction temperature 300 - 400 °C, reaction pressure 4.0 - 8.0 MPa, volume space velocity 0.5 - 5.0 h -1 , hydrogen-to-oil volume ratio 500 - 1500 Nm 3 / m 3 .

[0022] In one embodiment of the present invention, the carrier of the hydrotreating catalyst is selected from one or more of alumina, silica, titanium oxide, and zirconia. The Group VIII metal component is cobalt and / or nickel, and the Group VIB metal component is molybdenum and / or tungsten. Based on the oxide and with the hydrotreating catalyst as the reference, the content of cobalt and / or nickel is 1-10% by weight, and the content of molybdenum and / or tungsten is 10-45% by weight.

[0023] To maintain the sulfided state of the hydrotreating catalyst, it is preferred to add a sulfiding agent to the waste oil, and the concentration of the sulfiding agent is 0.01-0.5% by weight. The sulfiding agent is one or more of H2S, CS2, dimethyldisulfide, methyl sulfide, di-tert-butyl polysulfide (SZ 54 ), n-butyl sulfide, and thiophene.

[0024] The reactor in the hydrotreating reaction zone is a fixed-bed reactor. The reactor can be provided with multiple bed layers, and the reaction temperature rise can be controlled by injecting cold hydrogen between the bed layers, or by using the circulating oil method to control the reaction temperature rise, or both methods can be used simultaneously.

[0025] In the hydrotreating reaction zone, the waste oil mainly undergoes olefin saturation and hydrodeoxygenation reactions. Among them, the oxygen in the waste oil is mainly removed in the form of water production. The hydrotreating reaction effluent mainly consists of alkanes with 8-24 carbon atoms, and also includes water, carbon monoxide, carbon dioxide, hydrogen sulfide, ammonia, and hydrogen.

[0026] In one embodiment of the present invention, the hydrotreating reaction effluent enters a separator for gas-liquid separation to obtain a liquid stream, water, and a gas stream. The obtained liquid stream sequentially enters a stripping column for stripping and a dehydration column for dehydration to remove dissolved hydrogen sulfide, ammonia, and water, and obtain a liquid hydrocarbon.

[0027] The gas stream can be directly recycled or passed through a hydrogen purification unit to obtain a hydrogen-rich gas, and the obtained hydrogen-rich gas is recycled. The hydrogen purification unit can use conventional pressure swing adsorption technology or membrane separation technology.

[0028] In one embodiment of the present invention, the separator is selected from any combination of two or more of a hot high-pressure separator, a hot low-pressure separator, a cold high-pressure separator, and a cold low-pressure separator.

[0029] In step (2) of the present invention, the light components of the obtained liquid hydrocarbon enter the first hydroisomerization reaction zone and react with a hydroisomerization catalyst under the first hydroisomerization reaction conditions to obtain a first hydroisomerization reaction effluent. In step (3) of the present invention, the heavy components of the obtained liquid hydrocarbon enter the second hydroisomerization reaction zone and react with a hydroisomerization catalyst under the second hydroisomerization reaction conditions to obtain a second hydroisomerization reaction effluent.

[0030] In one embodiment of the present invention, the first hydroisomerization reaction conditions and the second hydroisomerization reaction conditions in steps (2) and (3) are as follows: the reaction temperature is 200 - 500 °C, the reaction pressure is 1.0 - 15.0 MPa, the volume hourly space velocity is 0.1 - 10.0 h -1 , and the hydrogen-to-oil volume ratio is 200 - 1500 Nm 3 / m 3 ;

[0031] Preferably, the first hydroisomerization reaction conditions and the second hydroisomerization reaction conditions are: the reaction temperature is 280 - 450 °C, the reaction pressure is 2.0 - 8.0 MPa, the volume hourly space velocity is 0.5 - 5.0 h -1 , and the hydrogen-to-oil volume ratio is 300 - 1000 Nm 3 / m 3 .

[0032] In a preferred embodiment of the present invention, the reaction temperature of the second hydroisomerization reaction conditions is 10 - 30 °C higher than that of the first hydroisomerization reaction conditions.

[0033] In one embodiment of the present invention, in the hydroisomerization catalyst, based on the total amount of the hydroisomerization catalyst, the content of the molecular sieve on a dry basis is 30 - 70% by weight, and in terms of elements, the content of the active metal component is 0.2 - 10% by weight.

[0034] In one embodiment of the present invention, the hydroisomerization catalyst further contains a binder, and the binder is alumina and / or silica;

[0035] Based on the total amount of the hydroisomerization catalyst, the content of the binder is 20 - 80% by weight.

[0036] In one embodiment of the present invention, the aspect ratio of the ZSM-48 molecular sieve is 1 - 2:1; the crystal size of the ZSM-48 molecular sieve is 300 - 700 nm, preferably 400 - 600 nm; the specific surface area of the ZSM-48 molecular sieve is 200 - 280 m 2 / g; the pore volume of the ZSM-48 molecular sieve is 0.2 - 0.3 mL / g.

[0037] In the present invention, the ZSM-48 molecular sieve has an ellipsoidal morphology with a small aspect ratio of length to width, a high silicon-aluminum ratio, a large specific surface area, and an extremely low content of alkaline metals in the carrier, and the obtained hydroisomerization catalyst has higher catalytic activity in the hydroisomerization reaction of liquid hydrocarbons.

[0038] In the present invention, the content of the alkaline metal oxide is determined by using a Rigaku 3271E X-ray fluorescence spectrometer (XRF) to analyze the composition of the sample. Those skilled in the art can understand that the conventional test accuracy of XRF is 10 ppm. Therefore, when the test result shows 0, it means that the content of the alkaline metal oxide is not higher than 0.001 wt%.

[0039] In one embodiment of the present invention, the method for preparing the hydroisomerization catalyst comprises the following steps:

[0040] Step 1: Shaping the dry powder of ZSM-48 molecular sieve to obtain a shaped carrier;

[0041] In the ZSM-48 molecular sieve, the molar ratio of silicon oxide to aluminum oxide is not less than 40, the specific surface area of the ZSM-48 molecular sieve is not less than 200 m 2 / g, the crystal grains of the ZSM-48 molecular sieve are ellipsoidal, the major axis does not exceed 700 nm and the aspect ratio is 1-3:1;

[0042] Wherein, based on the mass of the dry powder of the ZSM-48 molecular sieve, the water content of the dry powder of the ZSM-48 molecular sieve is less than 15 wt%;

[0043] Step 2: Subjecting the shaped carrier to ammonium exchange;

[0044] Step 3: Introducing an active metal component onto the product obtained in Step 2 to obtain a hydroisomerization catalyst;

[0045] Wherein, the active metal component is Pt and / or Pd.

[0046] In the present invention, the dry powder of the ZSM-48 molecular sieve refers to the dried ZSM-48 molecular sieve powder, and the drying is a conventional operation in the art, as long as the water content requirement of the dry powder of the ZSM-48 molecular sieve is met. In the conventional catalyst preparation process in the prior art, generally, the molecular sieve raw powder after drying and calcination needs to be subjected to ammonium exchange in a solution first, and then dried, shaped and calcined. On the one hand, the alkali metal content in the carrier after conventional ammonium exchange is generally 0.01-1 wt%, and the catalytic activity is limited; on the other hand, the post-treatment of the molecular sieve raw powder after direct ammonium exchange is difficult. The inventors of the present invention found in the research that by shaping the dry powder of the ZSM-48 molecular sieve first and then performing ammonium exchange, the alkali metal content in the carrier can be greatly reduced and the catalytic activity of the catalyst can be improved.

[0047] In the present invention, the method for testing the water content is as follows: Take the dry powder of ZSM-48 molecular sieve with a mass of M and place it in an oven. Dry it at 105 - 110 °C for about 6 - 8 h until the weight of the sample no longer changes. Weigh the dried sample, denoted as M after drying, and the water content of the dry powder of ZSM-48 molecular sieve can be calculated.

[0048] Water content (wt%) = (M - M after drying) / M × 100%.

[0049] In the present invention, preferably, the preparation method of the ZSM-48 molecular sieve comprises the following steps:

[0050] (1) Provide a mixture containing a silicon source, an alkali source, an aluminum source, a template agent, water, a molecular sieve mother liquor, and seeds;

[0051] (2) Carry out a crystallization reaction on the mixture; the conditions of the crystallization reaction include: reacting at 20 °C - 50 °C for 1 - 20 h, reacting at 50 °C - 80 °C for 1 - 34 h, and then reacting at 80 °C - 180 °C for 1 - 70 h;

[0052] (3) Carry out solid-liquid separation on the mixture obtained from the crystallization reaction in step (2) to obtain the ZSM-48 molecular sieve and the molecular sieve mother liquor, and the molecular sieve mother liquor is returned to step (1);

[0053] This method further optionally includes step (4), and step (4) includes: subjecting the molecular sieve mother liquor to acidification deposition, and then carrying out solid-liquid separation, and the obtained filtrate is returned to step (1);

[0054] The mass percentage of the added seeds in step (1) based on the mass of the silicon source is not less than 10%, and the silicon source is calculated as SiO₂.

[0055] According to the present invention, preparing the ZSM-48 molecular sieve by means of recycling the molecular sieve mother liquor and introducing seeds is conducive to the formation of small crystal grains. In the present invention, through a three-stage crystallization process at different temperatures, the progress and temperature of the crystallization reaction are strictly controlled. Compared with the prior art, by setting a crystallization reaction process at a low temperature, it helps to control the growth of crystal grains.

[0056] In the present invention, those skilled in the art can understand that the molecular sieve mother liquor can be obtained by arbitrarily selecting the above step (3) or steps (3) and (4). When the method provided by the present invention includes step (4), those skilled in the art can understand that the filtrate provides at least part of the molecular sieve mother liquor in step (1). By adopting the above preferred preparation method, through the way of recycling the molecular sieve mother liquor and introducing seeds, it is conducive to the formation of small crystal grains.

[0057] In the present invention, the proportions of the raw materials in step (1) can be adjusted according to actual requirements. To improve the performance of the molecular sieve in the ZSM-48 molecular sieve precursor and thus further improve the catalytic performance of the catalyst, preferably, the composition of each component in the mixture described in step (1) calculated by molar amount satisfies the following relationships:

[0058] R / SiO2 = 0.01 - 0.4, preferably 0.01 - 0.08;

[0059] M + / SiO2 = 0.01 - 0.4, preferably 0.1 - 0.2;

[0060] Al2O3 / SiO2 = 0 - 0.02, preferably 0.01 - 0.015;

[0061] H2O / SiO2 = 5 - 30, preferably 5 - 20;

[0062] Among them, SiO2 refers to SiO2 in the silicon source, R represents the template agent, and M + represents the base source.

[0063] According to the present invention, preferably, the conditions of the crystallization reaction in step (2) include: reacting at 20°C - 50°C for 6 - 20 h, reacting at 50°C - 80°C for 12 - 34 h, and then reacting at 80°C - 180°C for 48 - 70 h.

[0064] In the present invention, the amount of the seed crystal is relatively large. Preferably, the mass percentage of the added seed crystal in step (1) in the mass of the silicon source is 10 - 30%, preferably 20 - 30%; adopting the above preferred implementation mode is conducive to forming more crystal nuclei, and the prepared molecular sieve has the characteristics of small crystal grains.

[0065] According to the present invention, preferably, in the mixture described in step (1), the amount of the molecular sieve mother liquor is less than the amount of water. Further preferably, the mass percentage of the added molecular sieve mother liquor in step (1) in the total mass of the molecular sieve mother liquor and water in step (1) is not more than 50%, more preferably 10 - 30%. In the above preferred cases, it helps to form a molecular sieve with small crystal grains and a high specific surface area.

[0066] According to the present invention, preferably, in step (4), the acidification deposition includes: adding an acid to the molecular sieve mother liquor and adjusting the pH value to 5 - 7, preferably 5 - 6.5.

[0067] Preferably, the time of the acidification deposition is 0.5 - 4 h.

[0068] In the present invention, the selection range of the silicon source, alkali source, aluminum source, and template agent in step (1) is relatively wide, and the above raw materials are all conventional selections in the art. Generally, the above raw materials should be mixed into a uniform gel by corresponding means, for example, they can be mixed by stirring.

[0069] According to the present invention, preferably, the silicon source is selected from at least one of silica sol, precipitated silica, fumed silica, water glass, and tetraethyl orthosilicate; more preferably, it is silica sol.

[0070] According to the present invention, preferably, the alkali source is selected from alkaline metal salts, preferably at least one of sodium hydroxide, potassium hydroxide, and calcium hydroxide; more preferably, it is sodium hydroxide.

[0071] According to the present invention, preferably, the aluminum source is selected from at least one of pseudoboehmite, aluminum sulfate, aluminum isopropoxide, and sodium aluminate; more preferably, it is pseudoboehmite.

[0072] According to the present invention, preferably, the template agent is selected from at least one of ethylenediamine, 1,3-propanediamine, 1,4-butanediamine, 1,5-pentanediamine, 1,6-hexanediamine, 1,7-heptanediamine, 1,8-octanediamine, 1,9-nonanediamine, hexamethylammonium bromide, hexamethylammonium chloride, and hexamethylammonium hydroxide; more preferably, it is at least one of 1,6-hexanediamine, hexamethylammonium bromide, hexamethylammonium chloride, and hexamethylammonium hydroxide.

[0073] In the present invention, preferably, the seed crystal is a ZSM-48 molecular sieve seed crystal, and the molar ratio of silicon oxide to aluminum oxide in the ZSM-48 molecular sieve seed crystal is not less than 40, preferably 45 - 500. The silicon-aluminum ratio in the ZSM-48 molecular sieve seed crystal mainly depends on the feeding amounts of the silicon source and aluminum source in the raw materials and the preparation method.

[0074] In the XRD diffraction pattern of the calcined ZSM-48 molecular sieve raw powder synthesized by the existing technical methods at present, the peak positions of the diffraction peaks generally appear at 2θ angles of 7.5°, 21.2°, 22.8°, and 31.3°. Among them, the diffraction peak at 21°-22° is the highest, while the diffraction peak at 7°-8° has a relatively weak intensity. The researchers of the present invention found that by adopting a specific synthesis method, the preferred ZSM-48 molecular sieve seeds of the present invention can be prepared. In the X-ray diffraction pattern of the calcined ZSM-48 molecular sieve seeds, the relative peak height of the diffraction peak at 2θ angle of 7°-8° is significantly higher than that of the diffraction peak at 7°-8° in the molecular sieve obtained by the prior art. Preferably, in the X-ray diffraction pattern of the calcined ZSM-48 molecular sieve seeds, taking the peak height of the diffraction peak at 2θ angle of 21°-22° as the reference value, the peak height of the diffraction peak at 2θ angle of 7°-8° is not less than 70% of the reference value, preferably 75%-135%. For example, the lower limit of the peak height range of the diffraction peak at 7°-8° can be 75%, 80%, 90%, etc. of the reference value, and the upper limit of the peak height range of the diffraction peak at 7°-8° can be 135%, 120%, 110%, 100%, etc. of the reference value. Due to the influence of factors such as samples and instruments, there may be a deviation of ±0.5° in the specific peak position of the 2θ angle in the present invention. The purpose of the calcination is to remove impurities such as template agents in the molecular sieve raw powder to obtain a more accurate XRD characterization result, and it will not have a substantial impact on the diffraction peaks in the XRD pattern of the molecular sieve itself. Therefore, the calcination conditions are based on removing impurities. For example, it can be calcined at 400-700°C for 1-8h. The ZSM-48 molecular sieve seeds prepared in the preparation examples of the present invention were calcined at 600°C for 4h before characterization.

[0075] In one embodiment of the present invention, the forming in step one includes: mixing the dry powder of ZSM-48 molecular sieve, a binder, and an auxiliary agent, and then performing forming and roasting;

[0076] The auxiliary agent is an inorganic acid, preferably nitric acid and / or hydrochloric acid;

[0077] The binder is selected from at least one of alumina, silica, pseudo-boehmite, and silica sol, preferably pseudo-boehmite.

[0078] In one embodiment of the present invention, relative to 100 parts by weight of the dry powder of ZSM-48 molecular sieve, the dosage of the binder is 20-60 parts by weight, and the dosage of the auxiliary agent is 2-20 parts by weight;

[0079] The roasting conditions include: the roasting temperature is 300-600°C, and the roasting time is 2-10h.

[0080] In one embodiment of the present invention, the ammonium exchange in step two includes: contacting the formed carrier with an aqueous solution of an ammonium salt;

[0081] The conditions for ammonium exchange include: the temperature is 70 - 120 °C, preferably 80 - 100 °C; the time is 1 - 8 h, preferably 2 - 5 h.

[0082] The concentration of the ammonium salt in the aqueous solution of the ammonium salt is 0.01 - 1 mol / L, preferably 0.1 - 1 mol / L.

[0083] The ammonium salt is selected from at least one of ammonium nitrate, ammonium sulfate, ammonium chloride, and ammonium acetate.

[0084] In one embodiment of the present invention, the method for introducing the active metal component in step three includes: impregnating the product in step two with a solution of a soluble compound containing the active metal component, and then drying and calcining to obtain the hydroisomerization catalyst;

[0085] The soluble compound containing the active metal component is selected from at least one of tetraamminepalladium nitrate, tetraamminepalladium acetate, dichlorotetraamminepalladium, tetraammineplatinum nitrate, tetraammineplatinum acetate, and dichlorotetraammineplatinum;

[0086] The temperature for drying is 80 - 120 °C, and the time for drying is 2 - 6 hours;

[0087] The temperature for calcining is 400 - 500 °C, and the time for calcining is 2 - 6 hours.

[0088] The hydroisomerization catalyst described in the present invention is a reduced-state hydroisomerization catalyst with good isomer selectivity. When in use, the metal active component of the hydroisomerization catalyst is in a reduced state. Therefore, the preparation method further includes: under a hydrogen atmosphere, reducing and activating the hydroisomerization catalyst obtained in step three, and the reduction and activation process can be carried out in a conventional manner in the art. Preferably, the reduction temperature is 300 - 500 °C, and the reduction time is 2 - 6 h.

[0089] The preferred preparation method of the hydroisomerization catalyst of the present invention has a short preparation process and simple operation. Based on the ZSM-48 molecular sieve with a specific structure, by forming first and then performing ammonium exchange, the post-treatment difficulty is low. At the same time, the alkali metal content in the catalyst is extremely low, and the obtained hydroisomerization catalyst has higher catalytic activity in the hydroisomerization reaction of liquid hydrocarbons.

[0090] In one embodiment of the present invention, the obtained first hydroisomerization reaction effluent and the second hydroisomerization reaction effluent enter a separator for gas-liquid separation to obtain a liquid stream and a gas stream. The obtained gas stream is recycled, and the obtained liquid stream enters a fractionating column for fractionation to obtain biocrude oil, biodiesel, and a biolubricant base oil. The obtained biodiesel fraction is sulfur-free, has a low freezing point, and a high cetane number. The properties of the obtained biolubricant base oil all meet the API Group II specifications for base oils.

[0091] The features of the present invention are as follows:

[0092] (1) The present invention can process waste oils and fats, not only produce biodiesel with a low freezing point, but also make full use of the heavy fractions of waste oils and fats to obtain a hydrocarbon-based biolubricant base oil. The present invention cuts the light and heavy components of liquid hydrocarbons and enters different hydroisomerization reaction zones. By using a zoning control method, the depth of hydroisomerization and cracking of different carbon numbers can be effectively controlled, and different target products can be obtained with high yields.

[0093] (2) The preferred hydroisomerization catalyst of the present invention has higher catalytic activity in the hydroisomerization reaction of liquid hydrocarbons and can significantly increase the yield of target products. BRIEF DESCRIPTION OF THE DRAWINGS

[0094] Figure 1 A process flow schematic diagram of one embodiment of the hydroprocessing method for waste oils and fats provided by the present invention;

[0095] Figure 2 is the X-ray diffraction pattern of the calcined seed crystal A1 obtained in Preparation Example 1-1;

[0096] Figure 3 is the X-ray diffraction pattern of the calcined seed crystal A3 obtained in Preparation Example 1-3;

[0097] Figure 4 is the SEM image of the ZSM-48 molecular sieve obtained in Preparation Example 2-1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0098] The present invention will be further described below with reference to the accompanying drawings, but the present invention is not limited thereby.

[0099] Figure 1 is a process flow schematic diagram of one embodiment of the hydroprocessing method for waste oils and fats provided by the present invention. As Figure 1As shown, waste oil 1, fresh hydrogen 2 and recycled hydrogen 25 enter the heating furnace 3 together and are heated to the temperature required for the reaction. The material at the outlet of the heating furnace enters the fixed-bed hydrotreating reactor 4 in the hydrotreating reaction zone and reacts with the hydrotreating catalyst under hydrotreating reaction conditions to obtain a hydrotreating reaction effluent. The obtained hydrotreating reaction effluent enters the hot high-pressure separator 5 for gas-liquid separation. The obtained gas-phase stream enters the cold high-pressure separator 6 for further gas-liquid separation. The water 9 separated from the cold high-pressure separator 6 is discharged from the device. The separated gas-phase stream 10 is recycled after being pressurized by the recycle hydrogen compressor 11. The liquid-phase stream 7 obtained from the hot high-pressure separator 5 and the liquid-phase stream 8 obtained from the cold high-pressure separator 6 enter the fractionating tower 12 together as liquid hydrocarbons for fractionation to obtain light liquid hydrocarbon components 13 and heavy liquid hydrocarbon components 14.

[0100] The obtained light liquid hydrocarbon components 13, fresh hydrogen 26 and recycled hydrogen 19 enter the hydroisomerization reactor 15 in the first hydroisomerization reaction zone and react with the hydroisomerization catalyst under the first hydroisomerization reaction conditions to obtain a first hydroisomerization reaction effluent. The obtained heavy liquid hydrocarbons 14 and fresh hydrogen 27 enter the hydroisomerization reactor 16 in the second hydroisomerization reaction zone and react with the hydroisomerization catalyst under the second hydroisomerization reaction conditions to obtain a second hydroisomerization reaction effluent.

[0101] The first hydroisomerization reaction effluent and the second hydroisomerization reaction effluent 17 enter the high-pressure separator 18 for gas-liquid separation. The obtained gas-phase stream 19 is recycled back to the hydroisomerization reactor 15. The obtained liquid-phase stream 20 enters the fractionating tower 21 for fractionation to obtain bio-naphtha 22, biodiesel 23 and bio-lubricating oil base oil 24.

[0102] The following examples will further illustrate the present invention, but should not be construed as limiting the present invention.

[0103] The hydroisomerization catalyst used in the examples and comparative examples was prepared by the following process.

[0104] In the following preparation examples and preparation comparative examples, the XRD characterization of the samples was carried out using a Bruker D5005 diffractometer, CuKα ray (λ = 0.154 nm), tube voltage 40 kV, tube current 30 mA, scanning range 5° - 35°, step size 0.013°, 1 step per second. The morphology and size of the samples were characterized using an S-4800 type scanning electron microscope (SEM) produced by Hitachi, with an acceleration voltage of 20 kV.

[0105] The composition of the sample, including the content of alkaline metal oxides, was determined using a Rigaku 3271E X-ray fluorescence spectrometer (XRF). The sample preparation method was the tablet pressing method, and the measurement conditions were a side-window rhodium target, a tube voltage of 50 kV, and a tube current of 50 mA.

[0106] The pore structure parameters of the product, such as specific surface area and pore volume, were measured by nitrogen adsorption and the BET method.

[0107] The following preparation examples are used to illustrate the preparation of the seed crystals.

[0108] Preparation Example 1-1

[0109] Aluminum sulfate, hexamethylenediamine hydroxide (HMOH), sodium hydroxide, and deionized water were mixed in a certain ratio and stirred for 30 min. Then, silica sol was added. The molar ratios of various substances were n(Al2O3):(HMOH):n(Na + ):n(H2O):n(SiO2) = 0.01:0.03:0.3:8:1. The mixture was transferred to a crystallization kettle and crystallized at room temperature with stirring for 6 h at a stirring speed of 400 rpm; then, it was crystallized at 80 °C for 24 h, and then heated to 180 °C for crystallization for 48 h. After crystallization, filtration was carried out, and the solid product was dried at 120 °C for 6 h. The obtained product was seed crystal A1. After filtration and drying after crystallization, the obtained product was seed crystal A1. The XRD diffraction peaks of seed crystal A1 after calcination at 600 °C for 4 h are shown Figure 1 , and the peak height of the diffraction peak at 7° - 8° is 108% of the peak height of the diffraction peak at 21° - 22°. The XRF analysis results and data such as specific surface area are shown in Table 1.

[0110] Preparation Example 1-2

[0111] Sodium aluminate, hexamethylenediamine chloride (HMCl), sodium hydroxide, and deionized water were mixed in a certain ratio and stirred for 30 min. Then, silica sol was added. The molar ratios of various substances were n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2) = 0.004:0.03:0.3:21:1. The mixture was transferred to a crystallization kettle and crystallized at room temperature with stirring for 12 h at a stirring speed of 350 rpm; it was crystallized at 60 °C for 12 h and at 160 °C for 48 h. After crystallization, filtration was carried out, and the product was dried at 120 °C for 6 h. The product obtained after filtration and drying after crystallization was seed crystal A2. In the XRD diffraction peaks after calcination at 600 °C for 4 h, the peak height of the diffraction peak at 7° - 8° is 115% of the peak height of the diffraction peak at 21° - 22°. The XRF analysis results and data such as specific surface area are shown in Table 1.

[0112] Preparation Example 1-3

[0113] Sodium aluminate, hexamethylenediamine chloride (HMCl), sodium hydroxide, and deionized water were mixed in a certain ratio, and after stirring for 30 min, silica sol was added. The molar ratios of various substances were n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2) = 0.004:0.03:0.3:21:1. The mixture was transferred to a crystallization kettle and crystallized with stirring at room temperature for 12 h, and the stirring speed was 350 rpm; it was crystallized at 170 °C for 60 h. After crystallization, the product obtained by filtration and drying was seed A3. After calcining seed A3 at 600 °C for 4 h, the XRD pattern was seen Figure 2 , and the peak height of the diffraction peak at 7° - 8° was 63% of the peak height of the diffraction peak at 21° - 22°. The XRF analysis results and specific surface area and other data are shown in Table 1.

[0114] The following preparation examples are used to illustrate the preparation of ZSM-48 molecular sieve.

[0115] Preparation Example 2-1

[0116] (1) Aluminum sulfate, hexamethylenediamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor were mixed in a certain ratio, and after stirring for 30 min, silica sol was added. The molar ratios of various substances were n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2) = 0.01:0.03:0.3:10:1. The mass percentage of the added molecular sieve mother liquor in the total mass of the molecular sieve mother liquor and water described in step (1) was 30%, and ZSM-48 seed A1 with 25% of the added SiO2 mass was added;

[0117] (2) The above mixture was transferred to a crystallization kettle and stirred at room temperature for 6 h, crystallized at 80 °C for 24 h, and crystallized at 170 °C for 48 h;

[0118] (3) After crystallization, filtration was carried out, and after drying at 120 °C for 6 h, the dried powder Z-1 of ZSM-48 molecular sieve was obtained, and the molecular sieve mother liquor was returned to step (1); after testing, the water content of Z-1 was 5 wt%.

[0119] The XRF analysis results of the silicon-aluminum ratio of Z-1 and specific surface area and other data are shown in Table 1, and the scanning electron microscope pictures are seen Figure 3 , and its morphology was ellipsoidal, the major axis of the particles was 300 - 700 nm, and the ratio of the major axis to the minor axis was about 1.1 - 1.4:1.

[0120] Preparation Example 2-2

[0121] (1) Mix sodium aluminate, hexamethylenediamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor in a certain ratio, stir for 30 minutes, and then add silica sol. The molar ratios of various substances are n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2) = 0.004:0.03:0.3:20:1. The mass percentage of the added molecular sieve mother liquor in the total mass of the molecular sieve mother liquor and water described in step (1) is 20%, and ZSM-48 seed crystal A2 accounting for 15% of the added SiO2 mass is added;

[0122] (2) Transfer the above mixture into a crystallization kettle, crystallize at 40 °C for 12 h, crystallize at 80 °C for 10 h, and crystallize at 170 °C for 48 h;

[0123] (3) After crystallization, filter, dry at 120 °C for 6 h to obtain the dried powder of ZSM-48 molecular sieve Z-2, and return the molecular sieve mother liquor to step (1); after testing, the water content of Z-2 is 6 wt%;

[0124] The XRF analysis results of the silicon-aluminum ratio of Z-2 and data such as specific surface area are shown in Table 1. Its morphology is ellipsoidal, the major axis of the particles is 300 - 600 nm, and the ratio of the major axis to the minor axis is about 1.1 - 1.4:1.

[0125] Comparative Preparation Example 1

[0126] (1) Mix aluminum sulfate, hexamethylenediamine chloride (HMCl), sodium hydroxide, and deionized water containing molecular sieve mother liquor in a certain ratio, stir for 30 minutes, and then add silica sol. The molar ratios of various substances are n(Al2O3):(HMCl):n(Na + ):n(H2O):n(SiO2) = 0.0125:0.03:0.3:30:1. ZSM-48 seed crystal A3 accounting for 25% of the added SiO2 mass is added. The mass percentage of the added molecular sieve mother liquor in the total mass of the molecular sieve mother liquor and water described in step (1) is 20%;

[0127] (2) Transfer the above mixture into a crystallization kettle, stir at room temperature for 6 h, crystallize at 80 °C for 24 h, and crystallize at 170 °C for 48 h;

[0128] (3) After crystallization, filter, dry at 120 °C for 6 h to obtain the dried powder of ZSM-48 molecular sieve DZ-1, and return the molecular sieve mother liquor to step (1); after testing, the water content of DZ-1 is 8 wt%;

[0129] The XRF analysis results of DZ-1 and data such as specific surface area are shown in Table 1. Its morphology is rod-shaped, and the ratio of the major axis to the minor axis is about 7:1.

[0130] Table 1

[0131]

[0132] The following preparation examples are used to illustrate the preparation of the hydroisomerization catalyst.

[0133] Preparation Example 3-1

[0134] 70 g of the Z-1 sample from Preparation Example 2-1 was mixed with 40 g of pseudoboehmite on a dry basis and 2 g of nitric acid solution, formed, and calcined at 580 °C for 3 h. Then the carrier strips were placed in a 0.5 M ammonium chloride solution and exchanged at 90 °C for 2 h. The carrier strips were taken out, dried, and the sodium oxide content was measured. The results are shown in Table 2.

[0135] Platinum diammine dichloride (with a Pt mass fraction of 57.3%) was poured into 100 g of deionized water and stirred until uniform. 100 g of the carrier was poured into the above solution and impregnated at room temperature for 4 h. Subsequently, the above catalyst precursor was dried at 120 °C for 4 h. Then it was calcined in a state of passing an air stream, the calcination temperature was 450 °C, and the time was 4 h. The obtained semi-finished catalyst was again placed in a hydrogen atmosphere and reduced at 400 °C for 4 h to obtain the catalyst. The obtained hydroisomerization catalyst was named CAT-1. In terms of elements, the Pt loading in the catalyst was 0.5 wt%.

[0136] Preparation Example 3-2

[0137] According to the method of Preparation Example 3-1 and the same catalyst composition, except that Z-2 from Preparation Example 2-2 was used to replace Z-1. After ammonium exchange, the carrier strips were taken out, dried, and the sodium oxide content was measured. The results are shown in Table 2. The obtained hydroisomerization catalyst was named CAT-2.

[0138] Comparative Preparation Example 3-1

[0139] According to the method of Preparation Example 3-1 and the same catalyst composition, except that DZ-1 from Comparative Preparation Example 1 was used to replace Z-1. After ammonium exchange, the carrier strips were taken out, dried, and the sodium oxide content was measured. The results are shown in Table 2. The obtained hydroisomerization catalyst was named DCAT-1.

[0140] Comparative Preparation Example 3-2

[0141] According to the method of Preparation Example 3-1 and the same catalyst composition, except that the Z-1 sample from Preparation Example 2-1 was calcined at 580 °C for 3 h, the obtained solid was first subjected to ammonium exchange and then extruded into strips. The sodium oxide content was measured. The results are shown in Table 2. The obtained hydroisomerization catalyst was named DCAT-2.

[0142] Table 2

[0143]

[0144] Example 1

[0145] In this example, waste oil A was used as the raw material, and the main properties of waste oil A are shown in Table 3.

[0146] The hydrotreating reaction zone was filled with 100 mL of hydrotreating catalyst. Its carrier was alumina. Based on the oxide and taking the hydrotreating catalyst as the reference, the nickel content was 4.0 wt%, and the tungsten content was 28.0 wt%.

[0147] The first hydroisomerization reaction zone was filled with 85 mL of hydroisomerization catalyst CAT-1.

[0148] The second hydroisomerization reaction zone was filled with 15 mL of hydroisomerization catalyst CAT-2.

[0149] Waste oil A and hydrogen entered the hydrotreating reaction zone together. Sulfurizing agent SZ was added to waste oil A 54 , and the concentration of the sulfurizing agent was 0.3 wt%. Under the hydrotreating reaction conditions, it contacted with the sulfided hydrotreating catalyst for reaction to obtain the hydrotreating reaction effluent. The hydrotreating reaction conditions were: reaction pressure 6.4 MPa, reaction temperature 365 °C, volume hourly space velocity 1.0 h -1 and hydrogen-oil volume ratio 1200. The obtained hydrotreating reaction effluent was subjected to gas-liquid separation to obtain liquid hydrocarbons, water, and gas streams. The final boiling point temperature of the obtained liquid hydrocarbons was less than 650 °C, the liquid hydrocarbon yield was 83 wt%, and in the obtained liquid hydrocarbons, the sulfur content was 1 μg / g and the nitrogen content was 1 μg / g.

[0150] The liquid hydrocarbons were cut to obtain light liquid hydrocarbon components and heavy liquid hydrocarbon components. The cutting point was 365 °C. Based on the raw material, the yield of the light liquid hydrocarbon components was 73 wt%, and the yield of the heavy liquid hydrocarbon components was 10 wt%.

[0151] The obtained light liquid hydrocarbon components entered the first hydroisomerization reaction zone. Under the first hydroisomerization reaction conditions, they contacted with the hydroisomerization catalyst for reaction to obtain the first hydroisomerization reaction effluent. The first hydroisomerization reaction conditions were: reaction temperature 320 °C, reaction pressure 6.4 MPa, volume hourly space velocity 1.0 h -1 and hydrogen-oil volume ratio 500,

[0152] The obtained heavy liquid hydrocarbon components entered the second hydroisomerization reaction zone. Under the second hydroisomerization reaction conditions, they contacted with the hydroisomerization catalyst for reaction to obtain the second hydroisomerization reaction effluent. The second hydroisomerization reaction conditions were: reaction temperature 340 °C, reaction pressure 6.4 MPa, volume hourly space velocity 1.0 h -1 and hydrogen-oil volume ratio 500,

[0153] After the first hydroisomerization reaction effluent and the second hydroisomerization reaction effluent undergo gas-liquid separation and liquid-phase fractionation, bio-naphtha, biodiesel, and bio-lubricant base oil are obtained.

[0154] The total liquid product yield of the first and second hydroisomerization reaction zones is 98 wt%, the yield of bio-naphtha (boiling range < 160 °C) is 2 wt%, the yield of biodiesel (boiling range 160 - 365 °C) is 85 wt%, the pour point of biodiesel is -20 °C, and the yield of bio-lubricant base oil (boiling range > 365 °C) is 11 wt%. Their properties all meet the API Group II specifications for base oil.

[0155] Example 2

[0156] In this example, waste oil B is used as the raw material. The main properties of waste oil B are shown in Table 3.

[0157] The hydrotreating reaction zone is filled with 100 mL of hydrotreating catalyst. Its carrier is alumina. Based on the oxide and taking the hydrotreating catalyst as the reference, the nickel content is 4.2 wt% and the molybdenum content is 26.5 wt%.

[0158] The first hydroisomerization reaction zone is filled with 80 mL of hydroisomerization catalyst CAT-1.

[0159] The second hydroisomerization reaction zone is filled with 20 mL of hydroisomerization catalyst CAT-2.

[0160] Waste oil B and hydrogen enter the hydrotreating reaction zone together. Dimethyl disulfide, a sulfurizing agent, is added to waste oil B, and the concentration of the sulfurizing agent is 0.25 wt%. Under the hydrotreating reaction conditions, it contacts the sulfurized hydrotreating catalyst for reaction to obtain the hydrotreating reaction effluent. The hydrotreating reaction conditions are: reaction pressure 6.4 MPa, reaction temperature 355 °C, volume space velocity 1.0 h -1 and hydrogen-oil volume ratio 1200. The obtained hydrotreating reaction effluent undergoes gas-liquid separation to obtain liquid hydrocarbons, water, and gas streams. The final boiling point temperature of the obtained liquid hydrocarbons is less than 650 °C, the liquid hydrocarbon yield is 83 wt%, and in the obtained liquid hydrocarbons, the sulfur content is 6 μg / g and the nitrogen content is 1 μg / g.

[0161] The liquid hydrocarbons are cut to obtain light liquid hydrocarbon components and heavy liquid hydrocarbon components. The cutting point is 365 °C. Based on the raw material, the yield of the light liquid hydrocarbon components is 68 wt% and the yield of the heavy liquid hydrocarbon components is 15 wt%.

[0162] The obtained light liquid hydrocarbon components enter the first hydroisomerization reaction zone and react with a hydroisomerization catalyst under the first hydroisomerization reaction conditions to obtain a first hydroisomerization reaction effluent. The first hydroisomerization reaction conditions are as follows: reaction temperature 320 °C, reaction pressure 6.4 MPa, volume space velocity 1.0 h -1 and a hydrogen-oil volume ratio of 500,

[0163] The obtained heavy liquid hydrocarbon components enter the second hydroisomerization reaction zone and react with a hydroisomerization catalyst under the second hydroisomerization reaction conditions to obtain a second hydroisomerization reaction effluent. The second hydroisomerization reaction conditions are as follows: reaction temperature 340 °C, reaction pressure 6.4 MPa, volume space velocity 1.0 h -1 and a hydrogen-oil volume ratio of 500,

[0164] After the first hydroisomerization reaction effluent and the second hydroisomerization reaction effluent are subjected to gas-liquid separation and liquid-phase fractionation, bio-naphtha, biodiesel, and bio-lubricating base oil are obtained.

[0165] The total liquid product yield of the first and second hydroisomerization reaction zones is 98 wt%, the yield of bio-naphtha (boiling range < 160 °C) is 2 wt%, the yield of biodiesel (boiling range 160 - 365 °C) is 78 wt%, the pour point of biodiesel is -20 °C, the yield of bio-lubricating base oil (boiling range > 365 °C) is 18 wt%, and the properties all meet the API Group II specifications for base oil.

[0166] Comparative Example 1

[0167] This comparative example uses the same raw materials, hydrotreating catalyst, and hydrotreating reaction conditions as in Example 1. The obtained hydrotreating reaction effluent is subjected to gas-liquid separation to obtain a liquid hydrocarbon, water, and gas stream.

[0168] The obtained liquid hydrocarbon is not fractionated and all enters a hydroisomerization reactor filled with 100 mL of hydroisomerization catalyst CAT-1. Under the conditions of a reaction pressure of 6.4 MPa, a reaction temperature of 340 °C, a volume space velocity of 1.0 h -1 and a hydrogen-oil volume ratio of 500, the liquid hydrocarbon undergoes a hydroisomerization reaction. After the hydroisomerization reaction effluent is subjected to gas-liquid separation and liquid-phase fractionation, bio-naphtha, biodiesel, and bio-lubricating base oil are obtained.

[0169] The total liquid product yield of the hydroisomerization reaction is 90 wt%, the yield of bio-naphtha (boiling range < 160 °C) is 5 wt%, the yield of biodiesel (boiling range 160 - 365 °C) is 77 wt%, the pour point of biodiesel is -20 °C, the yield of bio-lubricating base oil (boiling range > 365 °C) is 8 wt%, and the properties all meet the API Group II specifications for base oil.

[0170] Comparative Example 2

[0171] The first hydroisomerization reaction zone is filled with 80 mL of hydroisomerization catalyst DCAT-1.

[0172] The second hydroisomerization reaction zone is filled with 20 mL of hydroisomerization catalyst DCAT-2.

[0173] This comparative example uses the same raw materials, hydrotreating catalyst and hydrotreating reaction conditions as in Example 1. The effluent from the hydrotreating reaction is subjected to gas-liquid separation to obtain liquid hydrocarbons, water and gas streams.

[0174] The liquid hydrocarbons are cut to obtain light liquid hydrocarbon fractions and heavy liquid hydrocarbon fractions, and the cutting point is 295 °C.

[0175] The obtained light liquid hydrocarbon fractions enter the first hydroisomerization reaction zone and react with the hydroisomerization catalyst under the first hydroisomerization reaction conditions to obtain the effluent from the first hydroisomerization reaction. The first hydroisomerization reaction conditions are: reaction temperature 320 °C, reaction pressure 6.4 MPa, volume hourly space velocity 1.0 h -1 and hydrogen-oil volume ratio 500,

[0176] The obtained heavy liquid hydrocarbon fractions enter the second hydroisomerization reaction zone and react with the hydroisomerization catalyst under the second hydroisomerization reaction conditions to obtain the effluent from the second hydroisomerization reaction. The second hydroisomerization reaction conditions are: reaction temperature 340 °C, reaction pressure 6.4 MPa, volume hourly space velocity 1.0 h -1 and hydrogen-oil volume ratio 500,

[0177] The effluent from the first hydroisomerization reaction and the effluent from the second hydroisomerization reaction are subjected to gas-liquid separation and liquid-phase fractionation to obtain bio-naphtha, biodiesel and bio-lubricating base oil.

[0178] The total liquid product yield of the hydroisomerization reaction is 92 wt%, the yield of bio-naphtha (boiling range < 160 °C) is 5 wt%, the yield of biodiesel (boiling range 160 - 365 °C) is 70 wt%, the pour point of biodiesel is -20 °C, and the yield of bio-lubricating base oil (boiling range > 365 °C) is 17 wt%, and the properties all meet the API Group II specifications for base oil.

[0179] Table 3

[0180]

[0181]

Claims

1. A method for hydrogenating waste oils and fats, comprising: (1) waste oil and hydrogen enter a hydroprocessing reaction zone together, and under hydroprocessing reaction conditions, contact with a hydroprocessing catalyst to react to obtain a hydroprocessing reaction effluent, wherein the active metal component of the hydroprocessing catalyst is at least one metal component selected from Group VIII and / or at least one metal component selected from Group VIB, The resulting hydroprocessing reaction effluent is separated to obtain liquid hydrocarbons, water and gas streams. The liquid hydrocarbons are cut to obtain liquid hydrocarbon light components and liquid hydrocarbon heavy components. The cutting point is 360-370°C. (2) the liquid hydrocarbon light component obtained in step (1) enters the first hydroisomerization reaction zone, contacts with the hydroisomerization catalyst under the first hydroisomerization reaction conditions to react, and obtains a first hydroisomerization reaction effluent. (3) The liquid hydrocarbon heavy component obtained in step (1) enters a second hydroisomerization reaction zone, and is contacted with a hydroisomerization catalyst under the second hydroisomerization reaction conditions to react, thereby obtaining a second hydroisomerization reaction effluent. The first hydroisomerization reaction effluent and the second hydroisomerization reaction effluent are subjected to gas-liquid separation and liquid phase fractionation to obtain bio-naphtha, biodiesel and bio-lubricant base oil; In step (2) and step (3), the hydroisomerization catalyst described includes a carrier and an active metal component supported on the carrier. The carrier contains ZSM-48 molecular sieve. The molar ratio of silica to alumina in the ZSM-48 molecular sieve is not less than 40. The specific surface area of the ZSM-48 molecular sieve is not less than 200 m 2 / g. The crystal grains of the ZSM-48 molecular sieve are ellipsoidal, with a major axis not exceeding 700 nm and a major axis to minor axis ratio of 1 - 3:1; The active metal component is Pt and / or Pd; In the hydroisomerization catalyst, the content of the molecular sieve on a dry basis is 20-80% by weight, based on the total amount of the hydroisomerization catalyst, and the content of the active metal component on an element basis is 0.1-20% by weight; Wherein, based on the total amount of the carrier, the content of the basic metal oxide in the carrier is not higher than 0.001 wt %.

2. The method according to claim 1, characterized in that, The content of unsaponifiable matter in waste oil and fat is ≥ 2% by weight.

3. The method according to claim 1, characterized in that, The hydrotreating reaction conditions are as follows: reaction temperature is 250 - 450 °C, reaction pressure is 3.0 - 10.0 MPa, volume space velocity is 0.1 - 10.0 h -1 , and the hydrogen-to-oil volume ratio is 300 - 2000 Nm 3 / m 3 ; The preferred hydrotreating reaction conditions are as follows: reaction temperature 300 - 400 °C, reaction pressure 4.0 - 8.0 MPa, volumetric space velocity 0.5 - 5.0 h -1 , and the hydrogen-to-oil volume ratio is 500 - 1500 Nm 3 / m 3 .

4. The method according to claim 1, wherein The carrier of the hydroprocessing catalyst is selected from one or more of aluminum oxide, silicon oxide, titanium oxide, and zirconium oxide. The Group VIII metal component is cobalt and / or nickel, and the Group VIB metal component is molybdenum and / or tungsten. Calculated as oxides and based on the hydroprocessing catalyst, the content of cobalt and / or nickel is 1-10% by weight, and the content of molybdenum and / or tungsten is 10-45% by weight.

5. The method according to claim 1, wherein In step (1), the effluent from the hydrotreatment reaction enters a separator for gas-liquid separation to obtain a liquid stream, water and a gas stream. The obtained liquid stream enters a stripping tower for stripping and a dehydration tower for dehydration in sequence to remove dissolved hydrogen sulfide, ammonia and water to obtain liquid hydrocarbons.

6. The method according to claim 1, characterized in that, The first hydroisomerization reaction conditions and the second hydroisomerization reaction conditions described in step (2) and step (3) are as follows: the reaction temperature is 200 - 500 °C, the reaction pressure is 1.0 - 15.0 MPa, the volume space velocity is 0.1 - 10.0 h -1 , and the hydrogen-to-oil volume ratio is 200 - 1500 Nm 3 / m 3 ; Preferably, the first hydroisomerization reaction conditions and the second hydroisomerization reaction conditions are as follows: reaction temperature 280 - 450 °C, reaction pressure 2.0 - 8.0 MPa, volume space velocity 0.5 - 5.0 h -1 , hydrogen-to-oil volume ratio 300 - 1000 Nm 3 / m 3 .

7. The method according to claim 6, wherein The reaction temperature of the second hydroisomerization reaction condition is 10-30° C. higher than the reaction temperature of the first hydroisomerization reaction condition.

8. The method according to claim 1, wherein In the hydroisomerization catalyst, the molecular sieve content is 30-70% by weight on a dry basis, based on the total amount of the hydroisomerization catalyst, and the active metal component content is 0.2-10% by weight on an element basis.

9. The method according to claim 1 or 8, characterized in that, The hydroisomerization catalyst further contains a binder, which is aluminum oxide and / or silicon oxide; Based on the total amount of the hydroisomerization catalyst, the content of the binder is 20-80% by weight.

10. The method according to claim 1, wherein The aspect ratio of the ZSM-48 molecular sieve is 1-2:1; the crystal size of the ZSM-48 molecular sieve is 300-700 nm; the specific surface area of the ZSM-48 molecular sieve is 200-280 m 2 / g; the pore volume of the ZSM-48 molecular sieve is 0.2-0.3 mL / g.

11. The method according to claim 1, wherein The preparation method of the hydroisomerization catalyst comprises the following steps: Step 1: forming the dry powder of ZSM-48 molecular sieve to obtain a formed carrier; The molar ratio of silica to alumina in the ZSM-48 molecular sieve is not less than 40, and the specific surface area of the ZSM-48 molecular sieve is not less than 200 m 2 / g. The crystal grains of the ZSM-48 molecular sieve are ellipsoidal, with a major axis not exceeding 700 nm and a major axis to minor axis ratio of 1-3:1; Among them, based on the mass of the dried powder of the ZSM-48 molecular sieve, the water content of the dried powder of the ZSM-48 molecular sieve is less than 15% by weight; Step 2: Perform ammonium exchange on the shaped carrier; Step 3: Introduce an active metal component onto the product obtained in Step 2 to obtain a hydroisomerization catalyst; Among them, the active metal component is Pt and / or Pd.

12. The method according to claim 11, wherein The shaping in Step 1 includes: mixing the dried powder of the ZSM-48 molecular sieve, a binder, and an auxiliary agent, and then performing shaping and calcination; The auxiliary agent is an inorganic acid, preferably nitric acid and / or hydrochloric acid; The binder is selected from at least one of alumina, silica, pseudoboehmite, and silica sol, preferably pseudoboehmite.

13. The method according to claim 12, wherein Relative to 100 parts by weight of the dried powder of the ZSM-48 molecular sieve, the amount of the binder used is 20 - 60 parts by weight, and the amount of the auxiliary agent used is 2 - 20 parts by weight; The conditions for the calcination include: the calcination temperature is 300 - 600 °C, and the calcination time is 2 - 10 h.

14. The method according to claim 11, characterized in that The ammonium exchange in Step 2 includes: contacting the shaped carrier with an aqueous solution of an ammonium salt; The conditions for the ammonium exchange include: the temperature is 70 - 120 °C, and the time is 1 - 8 h; The concentration of the ammonium salt in the aqueous solution of the ammonium salt is 0.01 - 1 mol / L; The ammonium salt is selected from at least one of ammonium nitrate, ammonium sulfate, ammonium chloride, and ammonium acetate.

15. The method according to claim 11, wherein The method for introducing the active metal component in Step 3 includes: impregnating the product in Step 2 with a solution containing a soluble compound of the active metal component, and then performing drying and calcination to obtain the hydroisomerization catalyst; The soluble compound containing the active metal component is selected from at least one of tetraamminepalladium nitrate, tetraamminepalladium acetate, dichlorotetraamminepalladium, tetraammineplatinum nitrate, tetraammineplatinum acetate, and dichlorotetraammineplatinum; The temperature for the drying is 80 - 120 °C, and the drying time is 2 - 6 hours; The temperature for the calcination is 400 - 500 °C, and the calcination time is 2 - 6 hours.

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