Regeneration modification method of waste catalytic cracking catalyst and high-chlorine diesel oil dechlorination method

Abstract

The invention belongs to the technical field of oil refining, and particularly relates to a regeneration modification method of a waste catalytic cracking catalyst and a high-chlorine diesel oil dechlorination method. The regeneration modification method of the waste catalytic cracking catalyst comprises the following steps: (1) regenerating the catalyst; (2) preparing a CuY molecular sieve; and (3) modifying the catalyst. The method is simple, convenient and suitable for industrial large-scale production, the waste catalytic cracking catalyst is recycled, and the cost is reduced; the invention further provides a high-chlorine diesel oil dechlorination method, the waste catalytic cracking catalyst is regenerated and modified and then used for dechlorination of the high-chlorine diesel oil, and a feasible scheme is provided for upgrading utilization of the high-chlorine diesel oil.

Description

Technical Field

[0001] The invention belongs to the technical field of oil refining, and in particular relates to a regeneration and modification method of a waste catalytic cracking catalyst and a dechlorination method for high-chlorine diesel. Background Art

[0002] Catalytic cracking catalyst is a catalyst with molecular sieve as the active component. After multiple regenerations, the activity of the catalytic cracking catalyst is insufficient for continued use, and a new catalytic cracking catalyst needs to be replaced, and the discarded catalytic cracking catalyst is the spent catalytic cracking catalyst. Due to the large amount of catalytic cracking catalyst used, a large amount of spent catalytic cracking catalyst is generated every year. The spent catalytic cracking catalyst is a hazardous waste, and its recycling and treatment standards are strict. If the spent catalytic cracking catalyst is recycled, the production cost can be greatly reduced and the economic benefits can be improved.

[0003] Chinese invention patent CN113797981A provides a method for resurrecting a waste catalytic cracking catalyst, comprising: calcining a waste catalytic cracking catalyst containing contaminated metals; placing the calcined product in an alkali solution containing a structural protective agent for alkali leaching; washing the product after alkali leaching with water and acid in turn to obtain a resurrected catalytic cracking catalyst; wherein the structural protective agent is selected from one or more of water glass, silica sol, sodium metaaluminate and molecular sieve mother liquor, and the contaminated metal includes vanadium. The crystallinity of the catalytic cracking catalyst resurrected by this method can be increased by 1% to 10%, the vanadium removal rate can reach 50% to 80%, and the micro-reaction activity of the cracking balance agent of the waste catalyst is increased by 10 to 15, and the obtained catalyst still has good activity stability after multiple cycles of regeneration.

[0004] Chinese invention patent CN110102310A discloses a method for preparing a tar lightening catalyst based on waste FCC catalyst, which uses waste FCC catalyst as an active metal source, places the waste FCC catalyst in a mixed acid of nitric acid and hydrofluoric acid for high-temperature digestion to obtain a digestion solution containing active metals, impregnates the digestion solution with a carbon material to obtain a precursor, and roasts it at 650~800℃ in a mixed atmosphere of CO2 and / or H2O and an inert gas to prepare a highly active tar lightening catalyst. The obtained tar lightening catalyst treats tar formed by pyrolysis of carbon-containing materials such as coal and biomass, and can further catalytically crack polycyclic aromatic hydrocarbons and oxygen-containing heterocycles in the tar to form light aromatic hydrocarbons such as benzene and toluene, and catalytically modify the tar to improve the quality of the tar. However, this patent mainly utilizes the active metal components in the waste catalytic cracking catalyst, and the carrier structure of the catalytic cracking catalyst has not been further recycled.

[0005] In recent years, as crude oil has become increasingly inferior and heavy, in order to improve the recovery rate of crude oil, a large amount of oil recovery additives need to be added during crude oil extraction. These oil recovery additives contain a certain amount of organic chlorides. In addition, the addition of chlorine-containing additives during the transportation and processing of crude oil will increase the chloride content in the oil. The chloride in the crude oil is hydrolyzed during the processing to produce HCl, which forms a "HCl-H2S-H2O" corrosion system dominated by HCl in the presence of water and H2S, causing serious corrosion to the equipment.

[0006] Inorganic chlorine in crude oil is generally removed by electro-desalting, but inorganic chlorine compounds are usually difficult to completely remove in the electro-desalting stage. Organic chlorine is generally reacted by hydrogenation to produce HCl, which is then absorbed and removed by a dechlorinating agent. Due to the high chlorine content, high-chlorine diesel generates a large amount of HCl during the hydrogenation process, which combines with NH3 produced by the decomposition of nitrides in crude oil to form NH4Cl, which will crystallize and enrich in the heat exchanger pipeline, blocking the pipeline, resulting in a large pressure drop in the heat exchanger and poor heat exchange effect, affecting the processing load and product quality of the device. In severe cases, the plant needs to be shut down to deal with the heat exchanger problem. In addition, a large part of the pipelines of the hydrogenation unit equipment are made of stainless steel, and the generated HCl is very corrosive to the equipment. The hydrogenation reaction system belongs to a high-pressure hydrogen system. Once the equipment leaks, the consequences are very serious. This method not only causes severe corrosion to the equipment during the hydrogenation process, but also has the problem of difficulty in completely removing organic chlorides. As residual chlorides migrate to the downstream process, some chlorides will be enriched in diesel. The presence of chlorine in diesel, on the one hand, causes serious corrosion and blockage to the condenser and pipeline; on the other hand, it can cause catalyst poisoning in subsequent processing equipment, resulting in catalyst deactivation.

[0007] Chinese invention patent CN1084547A provides a refining method for naphtha hydrodesulfurization, dechlorination, dearsenicization and aromatic saturation. In the first stage, the raw naphtha is hydrorefined to reduce the sulfur content to <0.5ppm, the chlorine content to <0.5ppm, and the arsenic content to <5ppb; in the second stage, the aromatics in the naphtha are hydrogenated and saturated to reduce the aromatic content to <1% (wt), and further remove trace sulfur, chlorine, and arsenic to reduce the sulfur content to <10ppb, the chlorine content to <60ppb, and the arsenic content to <0.5ppb, so as to become an excellent steam reforming feed, significantly extend the service life of the steam reforming catalyst, improve the production capacity of the device, and reduce the water-to-carbon ratio operation.

[0008] Chinese invention patent CN103611566A discloses a catalyst for removing organic chlorine from high oxygen content oil products and its preparation method. First, a molecular sieve MgAl2O4-Al2O3 composite carrier containing an additive P is prepared, and then the carrier is impregnated with active components Ni or Co and Mo, W and a water-soluble compound of an additive Ce, and then dried and calcined to prepare a hydrodechlorination catalyst. The catalyst needs to completely convert organic chlorides in oil products into hydrogen chloride under hydrogen conditions.

[0009] Chinese invention patent CN1095702A discloses a reaction of reducing and dehalogenating halogenated hydrocarbons and dehalogenating ortho-dihalogenated hydrocarbons to olefins under mild conditions, using a highly active alkali metal hydride (such as NaH) synthesized by complex catalysis as a reducing agent. The reaction is carried out at normal pressure, low temperature (-40~100℃), and aprotic solvent. Not only aromatic halogenated hydrocarbons, but also alkyl halogenated hydrocarbons can undergo dehalogenation reactions, especially for the dehalogenation of ortho-dihalides to olefins. Although the above-mentioned regenerable adsorbent and reducing agent have mild reaction conditions, they are expensive and have harsh preparation conditions.

[0010] Chinese invention patent CN201510379628A provides a reaction system for hydrodechlorination of chlorinated diesel, and a method for hydrodechlorination of chlorinated diesel using the system, in view of the shortcomings of the prior art that the dechlorinating agent in the upper part of the dechlorinating agent bed is covered by iron-containing impurities and the utilization rate of the dechlorinating agent in the middle and lower parts is low. The system can avoid the coverage of iron-containing impurities and improve the utilization rate of the dechlorinating agent.

[0011] Chinese invention patent CN104830369B discloses a high-chlorine gasoline and diesel injection coking furnace high-temperature reaction dechlorination device, which uses a low-temperature high-pressure oil pump to increase the pressure and then injects the high-chlorine gasoline and diesel into the furnace tube instead of softened water and heats it to about 495°C. After cracking and condensation reactions in the coke tower, chloride ions exist in the coke, and the volatilized oil and gas enter the distillation tower through the top of the coke tower. After multiple contacts between the gas phase and the liquid phase, products with chloride ions <5ppm are separated. Summary of the invention

[0012] In order to solve the above technical problems, the present invention provides a method for regenerating and modifying waste catalytic cracking catalysts. The method is simple and suitable for large-scale industrial production, so that the waste catalytic cracking catalysts can be reused, thereby reducing costs. The present invention also provides a method for dechlorinating high-chlorine diesel, in which the waste catalytic cracking catalysts are regenerated and modified and then used for dechlorinating high-chlorine diesel, providing a feasible solution for the quality improvement and utilization of high-chlorine diesel.

[0013] The method for regenerating and modifying a waste catalytic cracking catalyst of the present invention comprises the following steps: (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first charring and a second charring in the reactor in sequence to obtain a charred catalyst; (2) Preparation of CuY molecular sieve: Add NaY molecular sieve into nitric acid aqueous solution for ion exchange, filter, wash with water, and obtain HY molecular sieve; add HY molecular sieve into copper nitrate aqueous solution for ion exchange, filter, wash with water, and dry to obtain CuY molecular sieve; (3) Catalyst modification: The charred catalyst and CuY molecular sieve are mixed, a medium is added and stirred, and then ground until the solid particle size is less than 3 μm to obtain a mixed slurry; the mixed slurry is spray-dried, and the obtained particles are solidified to obtain the product.

[0014] Preferably, the first charring process conditions are: slightly positive pressure, reactor inlet temperature 450-590°C, nitrogen space velocity 800-1500h -1 , air speed 60~150h -1 , charring time 2~6h; further preferably, the first charring reactor inlet temperature 480~580℃, nitrogen space velocity 950-1200h -1 , air speed 75-120h -1 , charring time 3~5h.

[0015] Preferably, the second charring process conditions are: slightly positive pressure, reactor inlet temperature 499-606°C, nitrogen space velocity 800-1500h -1 , air speed 200~650h -1 , charring time 3~9h; further preferably, the second charring reactor inlet temperature 510~580℃, nitrogen space velocity 950~1200h -1 , air speed 300~600h -1 , scorching time 4~8h.

[0016] Preferably, in step (2), the concentration of the nitric acid aqueous solution is 0.2-1 mol / L, and the ion exchange time of the NaY molecular sieve in the nitric acid aqueous solution is 2-5 h; the concentration of the copper nitrate aqueous solution is 0.2-1 mol / L, and the ion exchange time of the HY molecular sieve in the copper nitrate aqueous solution is 3-8 h.

[0017] Preferably, in step (3), the mass ratio of the charred catalyst to the CuY molecular sieve is (3-7):1; the medium is deionized water or ethanol; the mass of the deionized water or ethanol is 15-35% of the mass of the charred catalyst; the stirring time is 30-70 min, and the rotation speed is 100-300 r / min; the grinding equipment is a grinder, the grinding speed is 200-400 r / min, and the grinding time is 40-120 min; the spray drying equipment is a spray dryer, the spray drying temperature is 650-800°C, and the spray drying time is 2-6 h; the curing temperature is 550-750°C, and the curing time is 2-6 h; further preferably, the curing temperature is 550-630°C, and the curing time is 3-5 h.

[0018] The regenerated and modified catalyst obtained by the regeneration and modification method of the waste catalytic cracking catalyst of the present invention has a particle size of 60-70% (wt.) of the regenerated and modified catalyst of 30-95 μm.

[0019] The method for dechlorinating high-chlorine diesel of the present invention comprises adding the regenerated modified catalyst of the present invention into a riser reactor to catalyze the thermal decomposition of organic chlorides in the high-chlorine diesel to generate small-molecule chlorides to obtain a post-reaction oil product, and then dechlorinating the post-reaction oil product using modified acrylic fiber.

[0020] Preferably, the thermal cracking temperature is 350-420°C.

[0021] Preferably, the dechlorination is carried out in a continuous flow fixed bed reactor equipped with modified acrylic fiber, the dechlorination temperature is 40°C to 80°C, the dechlorination pressure is 0.1 to 3.5 MPa, and the liquid phase space velocity is 1 to 5 h -1 .

[0022] Preferably, the preparation method of the modified acrylic fiber comprises: placing the acrylic fiber in an amine compound solution for reaction, taking out the acrylic fiber after the reaction is completed, washing it with deionized water, and drying it to constant weight to obtain the modified acrylic fiber; The mass ratio of acrylic fiber to the amino compound in the amino compound solution is 1: (3-15), the reaction temperature is 90-150° C., the reaction time is 3-8 hours, and the drying temperature is 50-90° C. More preferably, the mass ratio of acrylic fiber to the amino compound in the amino compound solution is 1: (5-10), the reaction temperature is 100-140° C., and the reaction time is 4-6 hours.

[0023] Preferably, the amino compound solution comprises an amino compound and a solvent, the amino compound is one of polyethyleneamine, polyethyleneimine, triethylenetetramine or polyethylenepolyamine, 4-aminopyridine, 2-aminothiazole and 2-aminobenzothiazole, and the solvent is one of methanol, ethanol, toluene, n-hexane and water.

[0024] Thermal cracking is completed on the RU-II continuous riser catalytic cracking evaluation test device. The specific process is as follows: the regenerated modified catalyst reaches the bottom of the reactor through the retransmission line from the regenerator, and the high-chlorine diesel coking liquefied gas that has been pre-lifted and preheated enters the riser reactor to contact the regenerated modified catalyst for cracking reaction. The reactants and catalyst are lifted to the separator together, and after sedimentation and filtration, they enter the rear fractionation system from the top of the settler; the carbon deposited catalyst falls into the stripper, is stripped by steam, and is transported to the top of the regenerator through the waiting line; in the regenerator, the carbon deposited catalyst is regenerated by burning with air and then flows into the regeneration agent delivery line.

[0025] Among them, the circulation amount of the regenerated modified catalyst is controlled by the opening of the slide valve to be regenerated and the regeneration slide valve; under the reaction temperature of 350~420℃, the regenerated modified catalyst is used to carry out catalytic thermal cracking test to thermally crack the large molecular organic chlorides in the oil into small molecular chlorides.

[0026] The regenerated modified catalyst of the present invention has the dual functions of cracking and adsorption. In the thermal cracking process, part of the organic chloride is cracked to generate HCl and chloride salts that enter the oil product. At the same time, there is a polycondensation reaction, and part of the organic chlorine is also condensed to produce coke, and then the organic chlorine enters the regenerator for burning and is converted into HCl and salts. The lowest point temperature of the reactor is above 350°C, and there is no liquid phase. The HCl, NH4Cl and other substances produced in the reactor are quickly converted into the gas phase, and will not corrode the equipment body. In addition, part of the chloride in the high-chlorine diesel component is adsorbed on the surface of the catalytic cracking catalyst. The presence of the chloride enhances the acidic function of the catalyst, which is beneficial to improving the activity of the catalyst.

[0027] Compared with the prior art, the present invention has the following beneficial effects: 1. The regeneration and modification method of the waste catalytic cracking catalyst of the present invention is simple and suitable for industrial large-scale production, so that the waste catalytic cracking catalyst can be reused and the cost can be reduced; 2. The present invention utilizes a regenerated modified catalyst to convert the difficult-to-remove organic chloride into an easily-removable inorganic chloride by catalytic thermal cracking, while improving the activity of the catalyst. Finally, modified acrylic fiber is used as a dechlorinating agent to achieve adsorption and removal of chlorides in oil products; 3. The present invention provides a method for dechlorinating high-chlorine diesel under non-hydrogen conditions, which provides a feasible solution for the quality improvement and utilization of high-chlorine diesel. DETAILED DESCRIPTION

[0028] The technical solution of the present invention will be clearly and completely described below in conjunction with embodiments.

[0029] Unless otherwise specified, all raw materials used in the examples are commercially available.

[0030] Example 1 The high-chlorine diesel dechlorination method of the present invention comprises adding the regenerated modified catalyst into a riser reactor to catalyze the thermal decomposition of organic chlorides in the high-chlorine diesel to generate small-molecule chlorides to obtain a reacted oil product, and then dechlorinating the reacted oil product using modified acrylic fiber.

[0031] Among them, thermal cracking is completed on the RU-II type continuous riser catalytic cracking evaluation test device. The specific process is as follows: the reaction temperature is 390℃, the regenerated modified catalyst reaches the bottom of the reactor through the retransmission line from the regenerator, and the high-chlorine diesel coking liquefied gas that has been pre-lifted and preheated enters the riser reactor to contact the regenerated modified catalyst for cracking reaction, and the reactants and catalysts are lifted to the separator together, and after sedimentation and filtration, they enter the rear fractionation system from the top of the settler; the carbon deposited catalyst falls into the stripper, is stripped by steam, and is transported to the top of the regenerator through the waiting line; in the regenerator, the carbon deposited catalyst is regenerated by burning with air and then flows into the regeneration agent delivery line.

[0032] The dechlorination was carried out in a continuous flow fixed bed reactor filled with modified acrylic fiber. The dechlorination temperature was 40°C, the dechlorination pressure was 0.1 MPa, and the liquid phase space velocity was 1 h -1 .

[0033] The method for regenerating and modifying a waste catalytic cracking catalyst of the present invention comprises the following steps: (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first charring and a second charring in the reactor in sequence to obtain a charred catalyst; The first charring process conditions: slightly positive pressure, reactor inlet temperature 550℃, nitrogen space velocity 1000h -1 , air speed 110 h -1 , charring time 3h.

[0034] Second charring process conditions: slightly positive pressure, reactor inlet temperature 560°C, nitrogen space velocity 1200h -1 , air speed 300h -1 , charring time 5h.

[0035] (2) Preparation of CuY molecular sieve: 500 g NaY molecular sieve was added to 0.3 mol / L nitric acid aqueous solution for ion exchange for 3 h, filtered and washed with water to obtain HY molecular sieve; HY molecular sieve was added to 0.3 mol / L copper nitrate aqueous solution for ion exchange for 4 h, filtered, washed with water and dried to obtain CuY molecular sieve; (3) Catalyst modification: The charred catalyst and CuY molecular sieve were mixed in a mass ratio of 4:1, and deionized water equivalent to 15% of the mass of the charred catalyst was added and stirred at a speed of 150 r / min for 30 min. Then, the mixture was sent to a grinder and ground at a speed of 300 r / min for 60 min until the solid particle size was less than 3 μm to obtain a mixed slurry. The mixed slurry was sent to a spray dryer and spray-dried at 700°C for 4 h. The obtained particles were cured at 550°C for 4 h.

[0036] The particle size of 60-70% (wt.) of the obtained regenerated modified catalyst is 30-95 μm.

[0037] Preparation method of modified acrylic fiber: 12g acrylic fiber is placed in 600g triethylenetetramine aqueous solution (containing 60g triethylenetetramine), reacted at 100°C for 4h, and after the reaction, the acrylic fiber is taken out, washed with deionized water, and dried at 60°C to constant weight to obtain modified acrylic fiber.

[0038] Example 2 The high-chlorine diesel dechlorination method of the present invention comprises adding the regenerated modified catalyst into a riser reactor to catalyze the thermal decomposition of organic chlorides in the high-chlorine diesel to generate small-molecule chlorides to obtain a reacted oil product, and then dechlorinating the reacted oil product using modified acrylic fiber.

[0039] Among them, thermal cracking is completed on the RU-II type continuous riser catalytic cracking evaluation test device. The specific process is as follows: the reaction temperature is 390℃, the regenerated modified catalyst reaches the bottom of the reactor through the retransmission line from the regenerator, and the high-chlorine diesel coking liquefied gas that has been pre-lifted and preheated enters the riser reactor to contact the regenerated modified catalyst for cracking reaction, and the reactants and catalysts are lifted to the separator together, and after sedimentation and filtration, they enter the rear fractionation system from the top of the settler; the carbon deposited catalyst falls into the stripper, is stripped by steam, and is transported to the top of the regenerator through the waiting line; in the regenerator, the carbon deposited catalyst is regenerated by burning with air and then flows into the regeneration agent delivery line.

[0040] The dechlorination was carried out in a continuous flow fixed bed reactor filled with modified acrylic fiber. The dechlorination temperature was 50°C, the dechlorination pressure was 0.1 MPa, and the liquid phase space velocity was 1 h -1 .

[0041] The method for regenerating and modifying a waste catalytic cracking catalyst of the present invention comprises the following steps: (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first charring and a second charring in the reactor in sequence to obtain a charred catalyst; The first charring process conditions: slightly positive pressure, reactor inlet temperature 570℃, nitrogen space velocity 1200h -1 , air speed 120 h-1 , charring time 5h.

[0042] Second charring process conditions: slightly positive pressure, reactor inlet temperature 580°C, nitrogen space velocity 1200h -1 , air speed 600h -1 , scorching time 7h.

[0043] (2) Preparation of CuY molecular sieve: 1000 g NaY molecular sieve was added to 0.7 mol / L nitric acid aqueous solution for ion exchange for 5 h, filtered and washed with water to obtain HY molecular sieve; HY molecular sieve was added to 0.8 mol / L copper nitrate aqueous solution for ion exchange for 7 h, filtered, washed with water and dried to obtain CuY molecular sieve; (3) Catalyst modification: The charred catalyst and CuY molecular sieve were mixed in a mass ratio of 5:1, and deionized water equivalent to 25% of the mass of the charred catalyst was added and stirred at a speed of 150 r / min for 30 min. Then, the mixture was sent to a grinder and ground at a speed of 300 r / min for 100 min until the solid particle size was less than 3 μm to obtain a mixed slurry. The mixed slurry was sent to a spray dryer and spray-dried at 800°C for 4 h. The obtained particles were then cured at 550°C for 4 h.

[0044] The particle size of 60-70% (wt.) of the obtained regenerated modified catalyst is 30-95 μm.

[0045] Preparation method of modified acrylic fiber: 15g acrylic fiber is placed in 810g polyethyleneimine aqueous solution (containing 90g polyethyleneimine), reacted at 130°C for 4h, and after the reaction, the acrylic fiber is taken out, washed with deionized water, and dried at 60°C to constant weight to obtain modified acrylic fiber.

[0046] Example 3 The high-chlorine diesel dechlorination method of the present invention comprises adding the regenerated modified catalyst into a riser reactor to catalyze the thermal decomposition of organic chlorides in the high-chlorine diesel to generate small-molecule chlorides to obtain a reacted oil product, and then dechlorinating the reacted oil product using modified acrylic fiber.

[0047] Among them, thermal cracking is completed on the RU-II type continuous riser catalytic cracking evaluation test device. The specific process is as follows: the reaction temperature is 390℃, the regenerated modified catalyst reaches the bottom of the reactor through the retransmission line from the regenerator, and the high-chlorine diesel coking liquefied gas that has been pre-lifted and preheated enters the riser reactor to contact the regenerated modified catalyst for cracking reaction, and the reactants and catalysts are lifted to the separator together, and after sedimentation and filtration, they enter the rear fractionation system from the top of the settler; the carbon deposited catalyst falls into the stripper, is stripped by steam, and is transported to the top of the regenerator through the waiting line; in the regenerator, the carbon deposited catalyst is regenerated by burning with air and then flows into the regeneration agent delivery line.

[0048] The dechlorination was carried out in a continuous flow fixed bed reactor filled with modified acrylic fiber. The dechlorination temperature was 50°C, the dechlorination pressure was 1 MPa, and the liquid phase space velocity was 2 h -1 .

[0049] The method for regenerating and modifying a waste catalytic cracking catalyst of the present invention comprises the following steps: (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first charring and a second charring in the reactor in sequence to obtain a charred catalyst; The first charring process conditions: slightly positive pressure, reactor inlet temperature 580℃, nitrogen space velocity 1000h -1 , air speed 120h -1 , charring time 5h.

[0050] Second charring process conditions: slightly positive pressure, reactor inlet temperature 580°C, nitrogen space velocity 1100h -1 , air speed 600h -1 , charring time 5h.

[0051] (2) Preparation of CuY molecular sieve: 1500g NaY molecular sieve was added to 1mol / L nitric acid aqueous solution for ion exchange for 5h, filtered and washed with water to obtain HY molecular sieve; HY molecular sieve was added to 1mol / L copper nitrate aqueous solution for ion exchange for 7h, filtered, washed with water and dried to obtain CuY molecular sieve; (3) Catalyst modification: The charred catalyst and CuY molecular sieve were mixed in a mass ratio of 4:1, and deionized water equivalent to 25% of the mass of the charred catalyst was added and stirred at a speed of 150 r / min for 30 min. Then, the mixture was sent to a grinder and ground at a speed of 300 r / min for 100 min until the solid particle size was less than 3 μm to obtain a mixed slurry. The mixed slurry was sent to a spray dryer and spray-dried at 800°C for 4 hours. The obtained particles were cured at 550°C for 4 hours.

[0052] The particle size of 60-70% (wt.) of the obtained regenerated modified catalyst is 30-95 μm.

[0053] Preparation method of modified acrylic fiber: 20g acrylic fiber is placed in 1000g 4-aminopyridine aqueous solution (containing 120g 4-aminopyridine), reacted at 140°C for 6h, and after the reaction, the acrylic fiber is taken out, washed with deionized water, and dried at 70°C to constant weight to obtain modified acrylic fiber.

[0054] Example 4 The high-chlorine diesel dechlorination method of the present invention comprises adding the regenerated modified catalyst into a riser reactor to catalyze the thermal decomposition of organic chlorides in the high-chlorine diesel to generate small-molecule chlorides to obtain a reacted oil product, and then dechlorinating the reacted oil product using modified acrylic fiber.

[0055] Among them, thermal cracking is completed on the RU-II type continuous riser catalytic cracking evaluation test device. The specific process is as follows: the reaction temperature is 390℃, the regenerated modified catalyst reaches the bottom of the reactor through the retransmission line from the regenerator, and the high-chlorine diesel coking liquefied gas that has been pre-lifted and preheated enters the riser reactor to contact the regenerated modified catalyst for cracking reaction, and the reactants and catalysts are lifted to the separator together, and after sedimentation and filtration, they enter the rear fractionation system from the top of the settler; the carbon deposited catalyst falls into the stripper, is stripped by steam, and is transported to the top of the regenerator through the waiting line; in the regenerator, the carbon deposited catalyst is regenerated by burning with air and then flows into the regeneration agent delivery line.

[0056] The dechlorination was carried out in a continuous flow fixed bed reactor filled with modified acrylic fiber. The dechlorination temperature was 50°C, the dechlorination pressure was 1 MPa, and the liquid phase space velocity was 2 h -1 .

[0057] The method for regenerating and modifying a waste catalytic cracking catalyst of the present invention comprises the following steps: (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first charring and a second charring in the reactor in sequence to obtain a charred catalyst; The first charring process conditions: slightly positive pressure, reactor inlet temperature 550℃, nitrogen space velocity 1000h -1 , air speed 90h -1 , charring time 5h.

[0058] Second charring process conditions: slightly positive pressure, reactor inlet temperature 600°C, nitrogen space velocity 900h -1 , air speed 600h -1 , charring time 5h.

[0059] (2) Preparation of CuY molecular sieve: 1500g NaY molecular sieve was added to 0.7mol / L nitric acid aqueous solution for ion exchange for 5h, filtered and washed with water to obtain HY molecular sieve; HY molecular sieve was added to 1mol / L copper nitrate aqueous solution for ion exchange for 7h, filtered, washed with water and dried to obtain CuY molecular sieve; (3) Catalyst modification: The charred catalyst and CuY molecular sieve were mixed in a mass ratio of 6:1, and deionized water equivalent to 25% of the mass of the charred catalyst was added and stirred at a speed of 150 r / min for 30 min. Then, the mixture was sent to a grinder and ground at a speed of 300 r / min for 100 min until the solid particle size was less than 3 μm to obtain a mixed slurry. The mixed slurry was sent to a spray dryer and spray-dried at 700°C for 4 h. The obtained particles were then cured at 550°C for 4 h.

[0060] The particle size of 60-70% (wt.) of the obtained regenerated modified catalyst is 30-95 μm.

[0061] Preparation method of modified acrylic fiber: 20g acrylic fiber is placed in 1300g 2-aminobenzothiazole aqueous solution (containing 150g 2-aminobenzothiazole), reacted at 130°C for 6h, and after the reaction, the acrylic fiber is taken out, washed with deionized water, and dried at 70°C to constant weight to obtain modified acrylic fiber.

[0062] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that in the dechlorination method of high-chlorine diesel, the catalyst used for thermal cracking is a fresh catalytic cracking catalyst, and the dechlorinating agent used for dechlorination is prepared according to the method of Example 1 in Chinese invention patent CN110841591A.

[0063] Among them, in this comparative example 1, a fresh catalytic cracking catalyst is used, and the thermal cracking test is completed on the RU-II type continuous riser catalytic cracking evaluation test device. The reaction temperature is 390°C. The regenerated catalyst reaches the bottom of the reactor through the retransmission line from the regenerator. The coking liquefied gas of a certain refinery that has been pre-lifted and preheated enters the riser reactor to contact the catalyst for cracking reaction. The reactants and catalyst are lifted to the separator together, and after sedimentation and filtration, they enter the rear fractionation system from the top of the settler. The carbon deposited catalyst falls into the stripper and is steam stripped and then transported to the top of the regenerator through the waiting line. In the regenerator, the carbon deposited catalyst is regenerated by burning with air. The regenerating agent flows into the regenerating agent delivery line. The circulation amount of the catalyst is controlled by the opening of the waiting slide valve and the regeneration slide valve. The cracked gas is measured by the dry gas meter. After the catalytic thermal cracking of the coking liquefied gas, the loss rate is about 7%.

[0064] Comparative Example 2 The dechlorination method of high-chlorine diesel in Comparative Example 2 is similar to that in Example 2 in that the used catalytic cracking catalyst is only subjected to a regeneration step without being modified.

[0065] The oil products of Examples 1 to 4 and Comparative Examples 1 to 2 were tested for chlorine content before and after dechlorination. The chlorine content in diesel was analyzed in accordance with NB / SH / T0977-2019 "Determination of chlorine content in light oil products - Single wavelength dispersive X-ray fluorescence spectrometry". The results are shown in Table 1.

[0066] Table 1 Chlorine content of oil before and after dechlorination It can be seen from Table 1 that the high-chlorine diesel of the present invention has better dechlorination effect. By comparing Example 1 with Comparative Example 1, it is proved that the dechlorination effect of using the regenerated modified catalyst for catalytic cracking and then using the modified acrylic fiber as a dechlorinating agent for dechlorination in the present invention is much higher than that of Comparative Example 1. Moreover, the regenerated modified catalyst of the present invention is obtained from the waste catalytic cracking catalyst, which is more cost-effective than using a fresh catalytic cracking catalyst.

[0067] By comparing Example 2 with Comparative Example 2, it is proved that the use of CuY molecular sieve for modification in the regeneration and modification method of the waste catalytic cracking catalyst in the present invention is conducive to the complete decomposition of organic chlorides, thereby achieving a better dechlorination effect in the subsequent dechlorination process.

Claims

1. A method for regenerating and modifying a waste catalytic cracking catalyst, characterized in that: The steps include: (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first charring and a second charring in the reactor in sequence to obtain a charred catalyst; (2) Preparation of CuY molecular sieve: Add NaY molecular sieve into nitric acid aqueous solution for ion exchange, filter, wash with water, and obtain HY molecular sieve; add HY molecular sieve into copper nitrate aqueous solution for ion exchange, filter, wash with water, and dry to obtain CuY molecular sieve; (3) Catalyst modification: The charred catalyst and CuY molecular sieve are mixed, a medium is added and stirred, and then ground until the solid particle size is less than 3 μm to obtain a mixed slurry; the mixed slurry is spray-dried, and the obtained particles are solidified to obtain the product.

2. The method for regenerating and modifying a waste catalytic cracking catalyst according to claim 1, characterized in that: The first charring process conditions: slightly positive pressure, reactor inlet temperature 450~590℃, nitrogen space velocity 800~1500h -1 , air speed 60~150h -1 , scorching time 2~6h; Second charring process conditions: slightly positive pressure, reactor inlet temperature 499~606℃, nitrogen space velocity 800~1500h -1 , air speed 200~650h -1 , scorching time 3~9h.

3. The method for regenerating and modifying a waste catalytic cracking catalyst according to claim 1, characterized in that: In step (2), the concentration of the nitric acid aqueous solution is 0.2-1 mol / L, and the ion exchange time of the NaY molecular sieve in the nitric acid aqueous solution is 2-5 h; the concentration of the copper nitrate aqueous solution is 0.2-1 mol / L, and the ion exchange time of the HY molecular sieve in the copper nitrate aqueous solution is 3-8 h.

4. The method for regenerating and modifying a waste catalytic cracking catalyst according to claim 1, characterized in that: In step (3), the mass ratio of the charred catalyst to the CuY molecular sieve is (3-7):1; the medium is deionized water or ethanol; the mass of the deionized water or ethanol is 15-35% of the mass of the charred catalyst; the stirring time is 30-70 min, and the rotation speed is 100-300 r / min; the grinding equipment is a grinder, the grinding speed is 200-400 r / min, and the grinding time is 40-120 min; the spray drying equipment is a spray dryer, the spray drying temperature is 650-800° C., and the spray drying time is 2-6 h; the curing temperature is 550-750° C., and the curing time is 2-6 h.

5. A regenerated and modified catalyst obtained by the regeneration and modification method of a spent catalytic cracking catalyst according to any one of claims 1 to 4.

6. A method for dechlorinating high-chlorine diesel, characterized in that: The regenerated modified catalyst of claim 5 is added to the riser reactor to catalyze the thermal decomposition of organic chlorides in high-chlorine diesel to generate small-molecule chlorides to obtain a reacted oil product, and then the reacted oil product is dechlorinated using modified acrylic fiber.

7. The method for dechlorinating high-chlorine diesel according to claim 6, characterized in that: The thermal cracking temperature is 350~420℃.

8. The method for dechlorinating high-chlorine diesel according to claim 6, characterized in that: Dechlorination is carried out in a continuous flow fixed bed reactor equipped with modified acrylic fiber. The dechlorination temperature is 40℃~80℃, the dechlorination pressure is 0.1~3.5Mpa, and the liquid phase space velocity is 1~5h -1 .

9. The method for dechlorinating high-chlorine diesel according to claim 6, characterized in that: The preparation method of modified acrylic fiber comprises: placing acrylic fiber in an amine compound solution for reaction, taking out the acrylic fiber after the reaction is completed, washing it with deionized water, and drying it to constant weight to obtain the modified acrylic fiber; The mass ratio of acrylic fiber to the amino compound in the amino compound solution is 1:(3-15), the reaction temperature is 90-150°C, the reaction time is 3-8h, and the drying temperature is 50-90°C.

10. The method for dechlorinating high-chlorine diesel according to claim 9, characterized in that: The amino compound solution comprises an amino compound and a solvent, wherein the amino compound is one of polyethyleneamine, polyethyleneimine, triethylenetetramine or polyethylenepolyamine, 4-aminopyridine, 2-aminothiazole and 2-aminobenzothiazole, and the solvent is one of methanol, ethanol, toluene, n-hexane and water.

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