Method for regeneration modification of waste spent catalytic cracking catalyst and method for dechlorination of high-chlorine diesel
By combining the regeneration and modification of spent catalytic cracking catalysts with the use of modified acrylonitrile fibers, the problems of spent catalyst regeneration and dechlorination of high-chlorine diesel have been solved, achieving efficient catalyst regeneration and improved diesel quality.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2023-11-02
- Publication Date
- 2026-05-15
AI Technical Summary
Waste catalytic cracking catalysts are difficult to regenerate and reuse, and chlorides in high-chlorine diesel are difficult to remove effectively, leading to equipment corrosion and catalyst deactivation, which affects processing efficiency and product quality.
By regenerating and modifying spent catalytic cracking catalysts, including first and second coking, CuY molecular sieve preparation and mixed spray drying, a regenerated modified catalyst is formed, which is then combined with modified acrylonitrile fibers for catalytic thermal cracking and adsorption dechlorination of high-chlorinated diesel.
It enables the recycling of spent catalysts, simplifies industrial production, reduces costs, and improves catalyst activity and diesel quality by removing organic chlorides through catalytic thermal cracking and adsorption, while avoiding equipment corrosion.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of oil refining technology, specifically relating to a method for regenerating and modifying spent catalytic cracking catalysts and a method for dechlorinating high-chlorine diesel. Background Technology
[0002] Catalytic cracking catalysts are primarily those using molecular sieves as the active component. After multiple regenerations, the activity of a catalytic cracking catalyst becomes insufficient for continued use, necessitating replacement with a new catalyst. The discarded catalyst is then considered spent catalytic cracking catalyst. Due to the large volume of catalytic cracking catalysts used, a significant amount of spent catalyst is generated annually. This spent catalyst is classified as hazardous waste, and its recycling and disposal standards are stringent. Regenerating and reusing spent catalytic cracking catalyst can significantly reduce production costs and improve economic efficiency.
[0003] Chinese invention patent CN113797981A discloses a method for revitalizing spent catalytic cracking catalysts, comprising: calcining spent catalytic cracking catalysts containing contaminating metals; leaching the calcined product in an alkaline solution containing a structure-protecting agent; and sequentially washing the leached product with water and acid to obtain revitalized catalytic cracking catalysts. The structure-protecting agent is selected from one or more of water glass, silica sol, sodium aluminate, and molecular sieve mother liquor, and the contaminating metals include vanadium. The revitalized catalytic cracking catalyst obtained by this method can increase the crystallinity by 1% to 10%, achieve a vanadium removal rate of 50% to 80%, and exhibit a 10% to 15% increase in micro-reaction activity compared to spent catalyst cracking balancers. The obtained catalyst retains good activity stability even after multiple cycles of regeneration.
[0004] Chinese invention patent CN110102310A discloses a method for preparing a tar-lightening catalyst based on spent FCC catalyst. The method uses spent FCC catalyst as an active metal source, placing it in a mixed acid solution of nitric acid and hydrofluoric acid for high-temperature digestion to obtain a digestion solution containing active metal. The digestion solution is then impregnated with carbon material to obtain a precursor, which is calcined at 650-800℃ under 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 can treat tar formed from the pyrolysis of carbonaceous materials such as coal and biomass, further catalytically cracking polycyclic aromatic hydrocarbons and oxygen-containing heterocycles in the tar to form light aromatic hydrocarbons such as benzene and toluene, thus improving the quality of the tar through lightening catalytic upgrading. However, this patent mainly utilizes the active metal components in the spent catalytic cracking catalyst; the support structure of the catalytic cracking catalyst is not further recycled.
[0005] In recent years, with the increasing deterioration and heavier nature of crude oil, a large amount of oil recovery additives need to be added during the crude oil extraction process to improve oil recovery rates. These additives all contain a certain amount of organochlorides. In addition, the addition of chlorine-containing additives during crude oil transportation and processing also increases the chloride content in the oil. During processing, the chlorides in crude oil hydrolyze to produce HCl, which, in the presence of water and H2S, forms an HCl-H2S-H2O type corrosion system, causing severe corrosion to equipment.
[0006] Inorganic chlorine in crude oil is typically removed using electrostatic desalting, but this process often fails to completely remove all inorganic chlorine compounds. Organic chlorine is usually removed by hydrogenation to produce HCl, which is then absorbed and removed by a dechlorinating agent. High-chlorinated diesel, due to its high chlorine content, generates large amounts of HCl during hydrogenation. This HCl combines with NH3 produced from the decomposition of nitrogen compounds in the crude oil to form NH4Cl, which crystallizes and accumulates in heat exchanger pipes, clogging them and causing significant pressure drops and reduced heat exchange efficiency. This impacts the processing load and product quality, and in severe cases, necessitates a shutdown to address the heat exchanger problem. Furthermore, a large portion of the hydrogenation unit's equipment and pipelines are made of stainless steel, and the generated HCl is highly corrosive to the equipment. The hydrogenation reaction system is a high-pressure, hydrogen-contaminated system; leaks can have extremely serious consequences. This method not only causes severe corrosion during hydrogenation but also suffers from the difficulty of completely removing organic chlorine compounds. As residual chlorides migrate downstream, some chlorides accumulate in diesel fuel. The presence of chlorine in diesel fuel causes severe corrosion and blockage to condensers and pipelines. On the other hand, it can also lead to catalyst poisoning in subsequent processing units, resulting in catalyst deactivation.
[0007] Chinese invention patent CN1084547A provides a refining method for naphtha hydrodesulfurization, dechlorination, dearsenic removal, and aromatic saturation. The first stage hydrorefining of the raw naphtha reduces the sulfur content to <0.5 ppm, chlorine content to <0.5 ppm, and arsenic content to <5 ppb. The second stage hydrogenates and saturates the naphtha with aromatics, reducing the aromatic content to <1% (wt), and further removes trace amounts of sulfur, chlorine, and arsenic, resulting in a sulfur content <10 ppb, a chlorine content <60 ppb, and an arsenic content <0.5 ppb. This makes it an excellent feedstock for steam reforming, significantly extending the service life of the steam reforming catalyst, increasing the plant's production capacity, and reducing the water-to-carbon ratio.
[0008] Chinese invention patent CN103611566A discloses a catalyst for removing organochlorines from highly oxygenated oils and its preparation method. First, a molecular sieve MgAl2O4-Al2O3 composite support containing the auxiliary agent P is prepared. Then, this support is impregnated with a water-soluble compound containing active components Ni or Co, Mo, W, and the auxiliary agent Ce. After drying and calcination, a hydrodechlorination catalyst is prepared. This catalyst needs to completely convert organochlorides in the oil to hydrogen chloride under hydrogen-containing conditions.
[0009] Chinese invention patent CN1095702A discloses a mild dehalogenation reaction of haloalkanes and a dehalogenation reaction of ortho-dihalogenated hydrocarbons to olefins, using highly active alkali metal hydrides (such as NaH) synthesized by complexation catalysis as reducing agents. The reaction is carried out at atmospheric pressure, low temperature (-40~100℃), and in aprotic solvents. Not only aryl halogenated hydrocarbons, but also alkyl halogenated hydrocarbons can undergo dehalogenation reactions, especially for the dehalogenation of ortho-dihalogenated hydrocarbons to olefins, where the reactivity is particularly high. Although the above-mentioned renewable adsorbents and reducing agents provide milder reaction conditions, they are expensive and require stringent preparation conditions.
[0010] Chinese invention patent CN201510379628A addresses the shortcomings of existing technologies in the hydrodechlorination process of chlorinated diesel, such as the upper dechlorinating agent bed being covered by iron-containing impurities and the low utilization rate of the middle and lower dechlorinating agents. It provides a reaction system for hydrodechlorinating chlorinated diesel and a method for using this system to hydrodechlorinate chlorinated diesel, which avoids the coverage of iron-containing impurities and improves the utilization rate of the dechlorinating agent.
[0011] Chinese invention patent CN104830369B discloses a high-temperature reaction dechlorination device for injecting high-chlorine gasoline and diesel into a coking furnace. The device uses a low-temperature high-pressure oil pump to pressurize the high-chlorine gasoline and diesel instead of softened water and inject it into the furnace tubes to be heated to about 495°C. The diesel undergoes a cracking and condensation reaction in the coke tower, and chloride ions are present in the coke. The volatilized oil and gas enter the fractionation tower through the top of the coke tower. Through multiple contacts between the gas phase and the liquid phase, a product with chloride ions <5ppm is separated. Summary of the Invention
[0012] To address the aforementioned technical problems, this invention provides a method for regenerating and modifying spent catalytic cracking catalysts. This method is simple, suitable for large-scale industrial production, and enables the reuse of spent catalytic cracking catalysts, thereby reducing costs. This invention also provides a method for dechlorinating high-chlorinated diesel fuel, in which spent catalytic cracking catalysts are regenerated and modified for use in the dechlorination of high-chlorinated diesel fuel, providing a feasible solution for the upgrading and utilization of high-chlorinated diesel fuel.
[0013] The method for regenerating and modifying spent catalytic cracking catalyst according to the present invention includes the following steps:
[0014] (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first coking and a second coking in the reactor to obtain a coked catalyst;
[0015] (2) Preparation of CuY molecular sieve: NaY molecular sieve was added to nitric acid aqueous solution for ion exchange, filtered and washed with water to obtain HY molecular sieve; HY molecular sieve was added to copper nitrate aqueous solution for ion exchange, filtered, washed with water and dried to obtain CuY molecular sieve;
[0016] (3) Modification of catalyst: The coking catalyst and CuY molecular sieve are mixed, a medium is added and stirred, and then ground until the solid particle size is <3μm to obtain a mixed slurry; the mixed slurry is spray-dried and the obtained particles are solidified to obtain the final product.
[0017] Preferred conditions for the first coking process: slightly positive pressure, reactor inlet temperature 450~590℃, nitrogen space velocity 800~1500 h⁻¹ -1 Air velocity 60~150 h -1 The coking time is 2-6 hours; more preferably, the inlet temperature of the first coking reactor is 480-580℃, and the nitrogen space velocity is 950-1200 h⁻¹. -1 Air velocity 75-120 h -1 The charring time is 3-5 hours.
[0018] Preferred conditions for the second coking process: slightly positive pressure, reactor inlet temperature 499~606℃, nitrogen space velocity 800~1500 h⁻¹ -1 Air velocity 200~650 h -1 The coking time is 3-9 hours; more preferably, the inlet temperature of the second coking reactor is 510-580℃, and the nitrogen space velocity is 950-1200 h⁻¹. -1 Air velocity 300~600 h -1 The charring time is 4-8 hours.
[0019] 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.
[0020] Preferably, in step (3), the mass ratio of the coking catalyst to the CuY molecular sieve is (3~7):1; the medium is deionized water or ethanol; the mass of deionized water or ethanol is 15~35% of the mass of the coking 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℃, and the spray drying time is 2~6 h; the curing temperature is 550~750℃, and the curing time is 2~6 h; more preferably, the curing temperature is 550~630℃, and the curing time is 3~5 h.
[0021] The regenerated modified catalyst obtained by the regeneration and modification method of the spent catalytic cracking catalyst described in this invention has a particle size of 30-95 μm, comprising 60-70% (wt.) of the regenerated modified catalyst.
[0022] The dechlorination method for high-chlorinated diesel described in this invention involves adding the regenerated modified catalyst described in this invention to a riser reactor to catalyze the thermal decomposition of organic chlorides in high-chlorinated diesel to generate small molecule chlorides, thereby obtaining the reacted oil product. The reacted oil product is then dechlorinated using modified acrylic fibers.
[0023] Preferably, the thermal decomposition temperature is 350~420℃.
[0024] Preferably, dechlorination is carried out in a continuous flow fixed-bed reactor containing modified acrylic fibers, with a dechlorination temperature of 40℃~80℃, a dechlorination pressure of 0.1~3.5 MPa, and a liquid hourly space velocity of 1~5 h⁻¹. -1 .
[0025] Preferred method for preparing modified acrylic fiber: acrylic fiber is placed in an amine compound solution for reaction. After the reaction is completed, the acrylic fiber is taken out, washed with deionized water, and dried to constant weight to obtain modified acrylic fiber.
[0026] The mass ratio of acrylic fiber to the amine compound in the amine compound solution is 1:(3~15), the reaction temperature is 90~150℃, the reaction time is 3~8h, and the drying temperature is 50~90℃. More preferably, the mass ratio of acrylic fiber to the amine compound in the amine compound solution is 1:(5~10), the reaction temperature is 100~140℃, and the reaction time is 4~6h.
[0027] Preferably, the amine compound solution comprises an amine compound and a solvent, wherein the amine 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.
[0028] The thermal cracking was completed on the RU-II type continuous riser catalytic cracking evaluation test unit. The specific process is as follows: the regenerated modified catalyst is brought to the bottom of the reactor from the regenerator via a refeed line. The high-chlorinated diesel coking liquefied gas, after pre-lifting and preheating, enters the riser reactor and contacts the regenerated modified catalyst to undergo a cracking reaction. The reactants and catalyst are lifted together to the separator, and after settling and filtration, they enter the downstream fractionation system from the top of the settling tank. The coked catalyst falls into the stripper, is stripped by steam, and is then transported to the top of the regenerator via a feed line. In the regenerator, the coked catalyst is regenerated by air coking and then flows into the regenerator feed line.
[0029] The circulation rate of the regenerated modified catalyst is controlled by the opening degree of the pre-generation slide valve 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.
[0030] This invention's regenerated modified catalyst possesses dual functions of cracking and adsorption. During the thermal cracking process, some organochlorides are cracked to generate HCl and chloride salts, which enter the oil. Simultaneously, a condensation reaction occurs, and some organochlorides are also condensed to produce coke. The organochlorides then enter the regenerator for coking, converting into HCl and salts. The reactor's lowest temperature is above 350°C, eliminating the presence of a liquid phase. The HCl, NH4Cl, and other substances produced in the reactor quickly convert to a gaseous phase, preventing corrosion of the equipment. Furthermore, some chlorides in the high-chlorinated diesel components are adsorbed onto the surface of the catalytic cracking catalyst. The presence of chlorides enhances the catalyst's acidity, thus improving its activity.
[0031] Compared with the prior art, the beneficial effects of the present invention are:
[0032] 1. The present invention provides a method for regenerating and modifying spent catalytic cracking catalysts. The method is simple and suitable for large-scale industrial production, enabling the reuse of spent catalytic cracking catalysts and reducing costs.
[0033] 2. This invention utilizes a regenerated modified catalyst to convert difficult-to-remove organic chlorides into easily removable inorganic chlorides through catalytic thermal cracking, while simultaneously improving the catalyst's activity. Finally, modified acrylic fiber is used as a dechlorinating agent to achieve the adsorption and removal of chlorides in oil products.
[0034] 3. This invention provides a method for dechlorinating high-chlorinated diesel under non-hydrogen-contaminated conditions, offering a feasible solution for upgrading and utilizing high-chlorinated diesel. Detailed Implementation
[0035] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments.
[0036] Unless otherwise specified, all raw materials used in the examples were commercially available.
[0037] Example 1
[0038] The dechlorination method for high-chlorinated diesel described in this invention involves adding the regenerated modified catalyst to a riser reactor to catalyze the thermal decomposition of organic chlorides in high-chlorinated diesel to generate small-molecule chlorides, thereby obtaining the reacted oil product. The reacted oil product is then dechlorinated using modified acrylic fibers.
[0039] The thermal cracking was 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 is brought to the bottom of the reactor from the regenerator via the re-transfer line. The high-chlorinated diesel coking liquefied gas, after pre-lifting and preheating, enters the riser reactor and contacts the regenerated modified catalyst to undergo a cracking reaction. The reactants and catalyst are lifted together to the separator. After settling and filtration, they enter the downstream fractionation system from the top of the settling tank. The coked catalyst falls into the stripper and is stripped by steam before being transported to the top of the regenerator via the waiting line. In the regenerator, the coked catalyst is regenerated by air coking and then flows into the regenerator conveying line.
[0040] Dechlorination was carried out in a continuous flow fixed-bed reactor containing modified acrylic fibers at a dechlorination temperature of 40°C and a dechlorination pressure of 0.1 MPa; the liquid hourly space velocity was 1 h⁻¹. -1 .
[0041] The method for regenerating and modifying spent catalytic cracking catalyst according to the present invention includes the following steps:
[0042] (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first coking and a second coking in the reactor to obtain a coked catalyst;
[0043] First coking process conditions: slightly positive pressure, reactor inlet temperature 550℃, nitrogen space velocity 1000h⁻¹ -1 air velocity 110 h -1 The charring time is 3 hours.
[0044] Secondary coking process conditions: slightly positive pressure, reactor inlet temperature 560℃, nitrogen space velocity 1200h⁻¹ -1 air speed 300 h -1 The charring time is 5 hours.
[0045] (2) Preparation of CuY molecular sieve: 500g of NaY molecular sieve was added to 0.3mol / L nitric acid aqueous solution for ion exchange for 3h, filtered and washed with water to obtain HY molecular sieve; HY molecular sieve was added to 0.3mol / L copper nitrate aqueous solution for ion exchange for 4h, filtered, washed with water and dried to obtain CuY molecular sieve;
[0046] (3) Modification of catalyst: The coking catalyst and CuY molecular sieve were mixed at a mass ratio of 4:1. 15% of deionized water equivalent to the mass of the coking 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 particle size of the solid particles was <3 μm to obtain a mixed slurry. The mixed slurry was spray-dried in a spray dryer at 700℃ for 4 h. The obtained particles were then solidified at 550℃ for 4 h to obtain the final product.
[0047] The resulting regenerated modified catalyst has a particle size of 30-95 μm in 60-70% (wt.).
[0048] Preparation method of modified acrylic fiber: 12g acrylic fiber is placed in 600g triethylenetetramine aqueous solution (containing 60g triethylenetetramine) and reacted at 100℃ for 4h. After the reaction is completed, the acrylic fiber is taken out, washed with deionized water, and dried at 60℃ to constant weight to obtain modified acrylic fiber.
[0049] Example 2
[0050] The dechlorination method for high-chlorinated diesel described in this invention involves adding the regenerated modified catalyst to a riser reactor to catalyze the thermal decomposition of organic chlorides in high-chlorinated diesel to generate small-molecule chlorides, thereby obtaining the reacted oil product. The reacted oil product is then dechlorinated using modified acrylic fibers.
[0051] The thermal cracking was 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 is brought to the bottom of the reactor from the regenerator via the re-transfer line. The high-chlorinated diesel coking liquefied gas, after pre-lifting and preheating, enters the riser reactor and contacts the regenerated modified catalyst to undergo a cracking reaction. The reactants and catalyst are lifted together to the separator. After settling and filtration, they enter the downstream fractionation system from the top of the settling tank. The coked catalyst falls into the stripper and is stripped by steam before being transported to the top of the regenerator via the waiting line. In the regenerator, the coked catalyst is regenerated by air coking and then flows into the regenerator conveying line.
[0052] Dechlorination was carried out in a continuous flow fixed-bed reactor containing modified acrylic fibers at a dechlorination temperature of 50°C and a dechlorination pressure of 0.1 MPa; the liquid hourly space velocity was 1 h⁻¹. -1 .
[0053] The method for regenerating and modifying spent catalytic cracking catalyst according to the present invention includes the following steps:
[0054] (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first coking and a second coking in the reactor to obtain a coked catalyst;
[0055] First coking process conditions: slightly positive pressure, reactor inlet temperature 570℃, nitrogen space velocity 1200h⁻¹ -1 air velocity 120 h -1 The charring time is 5 hours.
[0056] Secondary coking process conditions: slightly positive pressure, reactor inlet temperature 580℃, nitrogen space velocity 1200h⁻¹ -1 air speed 600 h -1 The charring time is 7 hours.
[0057] (2) Preparation of CuY molecular sieve: 1000g of 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 0.8mol / L copper nitrate aqueous solution for ion exchange for 7h, filtered, washed with water and dried to obtain CuY molecular sieve;
[0058] (3) Modification of catalyst: The coking catalyst and CuY molecular sieve were mixed at a mass ratio of 5:1. 25% of the mass of the coking 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 particle size of the solid particles was <3 μm to obtain a mixed slurry. The mixed slurry was spray-dried at 800℃ for 4 h in a spray dryer. The obtained particles were then solidified at 550℃ for 4 h to obtain the final product.
[0059] The resulting regenerated modified catalyst has a particle size of 30-95 μm in 60-70% (wt.).
[0060] Preparation method of modified acrylic fiber: 15g acrylic fiber is placed in 810g of polyethyleneimine aqueous solution (containing 90g of polyethyleneimine) and reacted at 130℃ for 4h. After the reaction is completed, the acrylic fiber is taken out, washed with deionized water, and dried at 60℃ to constant weight to obtain modified acrylic fiber.
[0061] Example 3
[0062] The dechlorination method for high-chlorinated diesel described in this invention involves adding the regenerated modified catalyst to a riser reactor to catalyze the thermal decomposition of organic chlorides in high-chlorinated diesel to generate small-molecule chlorides, thereby obtaining the reacted oil product. The reacted oil product is then dechlorinated using modified acrylic fibers.
[0063] The thermal cracking was 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 is brought to the bottom of the reactor from the regenerator via the re-transfer line. The high-chlorinated diesel coking liquefied gas, after pre-lifting and preheating, enters the riser reactor and contacts the regenerated modified catalyst to undergo a cracking reaction. The reactants and catalyst are lifted together to the separator. After settling and filtration, they enter the downstream fractionation system from the top of the settling tank. The coked catalyst falls into the stripper and is stripped by steam before being transported to the top of the regenerator via the waiting line. In the regenerator, the coked catalyst is regenerated by air coking and then flows into the regenerator conveying line.
[0064] Dechlorination was carried out in a continuous flow fixed-bed reactor containing modified acrylic fibers at a dechlorination temperature of 50°C and a dechlorination pressure of 1 MPa; the liquid hourly space velocity was 2 h⁻¹. -1 .
[0065] The method for regenerating and modifying spent catalytic cracking catalyst according to the present invention includes the following steps:
[0066] (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first coking and a second coking in the reactor to obtain a coked catalyst;
[0067] First coking process conditions: slightly positive pressure, reactor inlet temperature 580℃, nitrogen space velocity 1000h⁻¹ -1 air speed 120 h -1 The charring time is 5 hours.
[0068] Secondary coking process conditions: slightly positive pressure, reactor inlet temperature 580℃, nitrogen space velocity 1100h / h -1 air speed 600 h -1 The charring time is 5 hours.
[0069] (2) Preparation of CuY molecular sieve: 1500g of 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;
[0070] (3) Modification of catalyst: The coking catalyst and CuY molecular sieve were mixed at a mass ratio of 4:1. 25% of the mass of the coking catalyst was added and stirred at 150 r / min for 30 min. Then the mixture was sent to a grinder and ground at 300 r / min for 100 min until the particle size of the solid particles was <3 μm to obtain a mixed slurry. The mixed slurry was spray-dried at 800℃ for 4 h in a spray dryer. The resulting particles were then solidified at 550℃ for 4 h to obtain the final product.
[0071] The resulting regenerated modified catalyst has a particle size of 30-95 μm in 60-70% (wt.).
[0072] Preparation method of modified acrylic fiber: 20g acrylic fiber is placed in 1000g of 4-aminopyridine aqueous solution (containing 120g of 4-aminopyridine) and reacted at 140℃ for 6h. After the reaction is completed, the acrylic fiber is taken out, washed with deionized water, and dried at 70℃ to constant weight to obtain modified acrylic fiber.
[0073] Example 4
[0074] The dechlorination method for high-chlorinated diesel described in this invention involves adding the regenerated modified catalyst to a riser reactor to catalyze the thermal decomposition of organic chlorides in high-chlorinated diesel to generate small-molecule chlorides, thereby obtaining the reacted oil product. The reacted oil product is then dechlorinated using modified acrylic fibers.
[0075] The thermal cracking was 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 is brought to the bottom of the reactor from the regenerator via the re-transfer line. The high-chlorinated diesel coking liquefied gas, after pre-lifting and preheating, enters the riser reactor and contacts the regenerated modified catalyst to undergo a cracking reaction. The reactants and catalyst are lifted together to the separator. After settling and filtration, they enter the downstream fractionation system from the top of the settling tank. The coked catalyst falls into the stripper and is stripped by steam before being transported to the top of the regenerator via the waiting line. In the regenerator, the coked catalyst is regenerated by air coking and then flows into the regenerator conveying line.
[0076] Dechlorination was carried out in a continuous flow fixed-bed reactor containing modified acrylic fibers at a dechlorination temperature of 50°C and a dechlorination pressure of 1 MPa; the liquid hourly space velocity was 2 h⁻¹. -1 .
[0077] The method for regenerating and modifying spent catalytic cracking catalyst according to the present invention includes the following steps:
[0078] (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first coking and a second coking in the reactor to obtain a coked catalyst;
[0079] First coking process conditions: slightly positive pressure, reactor inlet temperature 550℃, nitrogen space velocity 1000h⁻¹ -1 air speed 90 h -1 The charring time is 5 hours.
[0080] Secondary coking process conditions: slightly positive pressure, reactor inlet temperature 600℃, nitrogen space velocity 900h⁻¹ -1 air speed 600 h -1 The charring time is 5 hours.
[0081] (2) Preparation of CuY molecular sieve: 1500g of 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;
[0082] (3) Modification of catalyst: The coking catalyst and CuY molecular sieve were mixed at a mass ratio of 6:1. 25% of the mass of the coking catalyst was added and stirred at a speed of 150 r / min for 30 min. Then it was sent to a grinder and ground at a speed of 300 r / min for 100 min until the particle size of the solid particles was <3 μm to obtain a mixed slurry. The mixed slurry was spray dried at 700℃ for 4 h in a spray dryer. The obtained particles were then solidified at 550℃ for 4 h to obtain the final product.
[0083] The resulting regenerated modified catalyst has a particle size of 30-95 μm in 60-70% (wt.).
[0084] Preparation method of modified acrylic fiber: 20g acrylic fiber is placed in 1300g of 2-aminobenzothiazole aqueous solution (containing 150g of 2-aminobenzothiazole) and reacted at 130℃ for 6h. After the reaction is completed, the acrylic fiber is taken out, washed with deionized water, and dried at 70℃ to constant weight to obtain modified acrylic fiber.
[0085] Comparative Example 1
[0086] The difference between Comparative Example 1 and Example 1 is that in the dechlorination method for high-chlorinated 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.
[0087] In Comparative Example 1, fresh catalytic cracking catalyst was used. The pyrolysis test was conducted on a RU-II type continuous riser catalytic cracking evaluation test device at a reaction temperature of 390℃. The regenerated catalyst was transported from the regenerator to the bottom of the reactor via a refeed line. Preheated and pre-lifted coking liquefied gas from a refinery entered the riser reactor and contacted the catalyst to undergo cracking. The reactants and catalyst were lifted together to the separator, and after settling and filtration, entered the downstream distillation system from the top of the settling tank. The coked catalyst fell into the stripper, was stripped with steam, and then transported to the top of the regenerator via a feed line. In the regenerator, the coked catalyst was regenerated by burning coke with air. The regenerator flowed into the regenerator feed line. The catalyst circulation rate was controlled by the opening of the feed valve and the regeneration valve. The cracked gas was metered by a dry gas meter. After catalytic pyrolysis of the coking liquefied gas, the loss rate was approximately 7%.
[0088] Comparative Example 2
[0089] The dechlorination method for high-chlorinated diesel in Comparative Example 2 is the same as that in Example 2, the used waste catalytic cracking catalyst only undergoes a regeneration step and is not modified.
[0090] The chlorine content of the oil products before and after dechlorination in Examples 1-4 and Comparative Examples 1-2 was tested. The chlorine content in diesel oil was analyzed according to NB / SH / T0977-2019 "Determination of Chlorine Content in Light Oil Products by Single Wavelength Dispersive X-ray Fluorescence Spectroscopy". The results are shown in Table 1.
[0091] Table 1 Chlorine content of oil products before and after dechlorination.
[0092]
[0093] As can be seen from Table 1, the dechlorination effect of high-chlorine diesel in this invention is better. By comparing Example 1 and Comparative Example 1, it is proved that the dechlorination effect of the present invention using a regenerated modified catalyst for catalytic cracking, and then using modified acrylonitrile fiber as a dechlorinating agent, is much higher than that of Comparative Example 1. Moreover, the regenerated modified catalyst of this invention is obtained from waste catalytic cracking catalyst, which is more cost-effective than using fresh catalytic cracking catalyst.
[0094] By comparing Example 2 and Comparative Example 2, it is demonstrated that the use of CuY molecular sieves for modification in the waste catalytic cracking catalyst regeneration and modification method of the present invention is beneficial to the complete decomposition of organochlorides, thereby achieving better dechlorination effect in the subsequent dechlorination process.
Claims
1. A method for dechlorinating high-chlorine diesel fuel, characterized in that, A regenerated modified catalyst is added to a riser reactor to catalyze the thermal decomposition of organochlorides in high-chlorinated diesel to generate small-molecule chlorides, resulting in a post-reaction oil product. The post-reaction oil product is then dechlorinated using modified acrylic fibers. The regenerated modified catalyst is obtained by regenerating and modifying spent catalytic cracking catalyst. The method for regenerating and modifying the spent catalytic cracking catalyst includes the following steps: (1) Catalyst regeneration: The spent catalytic cracking catalyst is subjected to a first coking and a second coking in the reactor to obtain a coked catalyst; (2) Preparation of CuY molecular sieve: NaY molecular sieve was added to nitric acid aqueous solution for ion exchange, filtered and washed with water to obtain HY molecular sieve; HY molecular sieve was added to copper nitrate aqueous solution for ion exchange, filtered, washed with water and dried to obtain CuY molecular sieve; (3) Modification of catalyst: The coking catalyst and CuY molecular sieve are mixed, a medium is added and stirred, and then ground until the solid particle size is <3μm to obtain a mixed slurry; the mixed slurry is spray-dried and the obtained particles are solidified to obtain the final product.
2. The method for dechlorinating high-chlorine diesel oil according to claim 1, characterized in that, First coking process conditions: slightly positive pressure, reactor inlet temperature 450~590℃, nitrogen space velocity 800~1500h⁻¹ -1 Air velocity 60~150 h -1 The charring time is 2-6 hours; Secondary coking process conditions: slightly positive pressure, reactor inlet temperature 499~606℃, nitrogen space velocity 800~1500h⁻¹ -1 Air velocity 200~650 h / h -1 The charring time is 3 to 9 hours.
3. The method for dechlorinating high-chlorine diesel oil 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 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 HY molecular sieve in the copper nitrate aqueous solution is 3~8 h.
4. The method for dechlorinating high-chlorine diesel oil according to claim 1, characterized in that, In step (3), the mass ratio of the coking catalyst to the CuY molecular sieve is (3~7):1; the medium is deionized water or ethanol; the mass of deionized water or ethanol is 15~35% of the mass of the coking 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℃, and the spray drying time is 2~6 h; the curing temperature is 550~750℃, and the curing time is 2~6 h.
5. The method for dechlorinating high-chlorine diesel oil according to claim 1, characterized in that, The thermal decomposition temperature is 350~420℃.
6. The method for dechlorinating high-chlorine diesel oil according to claim 1, characterized in that, Dechlorination was carried out in a continuous flow fixed-bed reactor containing modified acrylic fibers. The dechlorination temperature was 40℃~80℃, the dechlorination pressure was 0.1~3.5 MPa, and the liquid hourly space velocity was 1~5 h⁻¹. -1 .
7. The method for dechlorinating high-chlorine diesel oil according to claim 1, characterized in that, Preparation method of modified acrylic fiber: Acrylic fiber is placed in an amine compound solution for reaction. After the reaction is completed, the acrylic fiber is taken out, washed with deionized water, and dried to constant weight to obtain modified acrylic fiber. The mass ratio of acrylic fiber to amine compound in the amine compound solution is 1:(3~15), the reaction temperature is 90~150℃, the reaction time is 3~8h, and the drying temperature is 50~90℃.
8. The method for dechlorinating high-chlorine diesel oil according to claim 7, characterized in that, The amine compound solution includes an amine compound and a solvent. The amine compound is polyethyleneimine, and the solvent is one of methanol, ethanol, toluene, n-hexane, and water.
9. The method for dechlorinating high-chlorine diesel oil according to claim 7, characterized in that, The amine compound solution includes an amine compound and a solvent. The amine compound is a polyethylene polyamine, and the solvent is one of methanol, ethanol, toluene, n-hexane, and water.
10. The method for dechlorinating high-chlorine diesel oil according to claim 7, characterized in that, The amine compound solution includes an amine compound and a solvent. The amine compound is one of polyethyleneamine, triethylenetetramine, 4-aminopyridine, 2-aminothiazole, and 2-aminobenzothiazole. The solvent is one of methanol, ethanol, toluene, n-hexane, and water.