An apparatus and method for the production of ethylene from refinery dry gas

Abstract

The application belongs to the technical field of petroleum chemical industry, and particularly relates to a device and method for producing ethylene from refinery dry gas, wherein the device comprises a fluidized bed reactor, the bottom of the fluidized bed reactor is provided with a first feeding port, and the middle of the fluidized bed reactor is provided with a second feeding port; the top of the fluidized bed reactor is communicated with the bottom left side of a reactor settler, the bottom right side of the reactor settler is communicated with the top of a spent catalyst conveying pipe and a spent catalyst stripper; the left inner side wall of the reactor settler is provided with a settler inclined baffle which is inclined to the right and downward, and the right end of the settler inclined baffle is bent downward to extend into the first spent catalyst conveying pipe. The application can reduce secondary reactions and increase product yield; the application can improve the conversion rate of ethylene while saving energy consumption; the application can efficiently and continuously realize the production of ethylene from dry gas, and achieve the purposes of low carbon, energy saving, high efficiency and environmental protection.

Description

Technical Field

[0001] This patent belongs to the field of petrochemicals, specifically relating to an apparatus and method for producing ethylene from refinery dry gas. Background Technology

[0002] Dry gas is a gaseous byproduct of petrochemical production processes, and its sources are widespread. Ethane content is relatively high in dry gas from various sources; the ethane mass fraction in dry gas from refinery catalytic cracking, delayed coking, hydrocracking, and PSA desorption is all above 15%.

[0003] Currently, after refinery dry gas is enriched by ethylene or used directly, the ethane-rich dry gas is mainly used as fuel or as feedstock for ethylene steam cracking units. The former results in a significant waste of resources; the latter, due to the thermodynamic equilibrium limitations of steam cracking technology for ethylene production, involves high reaction temperatures and a strong tendency to coke, requiring frequent shutdowns of the cracking furnace to remove coke, thus preventing continuous production and severely impacting production efficiency.

[0004] Chinese patent CN106635163B discloses a method for preparing ethylene cracking feedstock by hydrogenating coking dry gas. The coking dry gas is first amine-washed to remove H2S, CO2, and coke powder, and then passes through a reactor from top to bottom. The reactor contains, from top to bottom, the following equipment and packing layers: a feed pipe, a gas feed distributor, a protective layer, an arsenic removal agent layer, a hydrogenation catalyst layer, a cold hydrogen feed tank, a gas distribution layer, a desulfurizing agent layer, a CO and CO2 methanation catalyst layer, a support layer, and a discharge pipe. The packing material in the protective layer and gas distribution layer is selected from at least one of a hydrogenation protective agent and inert packing material, and the support layer is filled with inert packing material. This invention uses a single reactor for one-step hydrogenation, avoiding the need for an additional reactor for CO and CO2 methanation catalysis, saving investment and shortening the process. By setting up a cold hydrogen feed tank and a gas distribution layer, the reactants are distributed twice, resulting in a more complete reaction and increasing the adaptability of the entire system to fluctuations in feedstock.

[0005] Existing technologies for utilizing dry gas require purification and separation, which increases the complexity of the process and energy consumption. In addition, some units, such as ethylene steam cracking units, require a high ethylene content (<1%) in the ethane feedstock, increasing the load on gas pretreatment and subsequent separation. Meanwhile, the process of preparing ethylene from dry gas and how to avoid secondary reactions during the preparation process to improve product yield are also important research topics. Summary of the Invention

[0006] To address the problems existing in the prior art, this invention provides an apparatus and method for producing ethylene from refinery dry gas. This invention can reduce secondary reactions and increase product yield; this invention can improve the conversion rate of ethylene while saving energy consumption; this invention can efficiently and continuously achieve the production of ethylene from dry gas, achieving the goals of low carbon, energy saving, high efficiency and environmental protection.

[0007] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0008] An apparatus for producing ethylene from refinery dry gas includes a fluidized bed reactor. The fluidized bed reactor has a first feed inlet at its bottom and a second feed inlet at its center. The top of the fluidized bed reactor is connected to the left side of the bottom of a reactor settling tank. The right side of the bottom of the reactor settling tank is connected to the top of a catalyst stripper via a first catalyst delivery pipe. The left inner wall of the reactor settling tank has a settling tank baffle that slopes downwards to the right, with its right end bent downwards and extending into the first catalyst delivery pipe. The bottom of the catalyst stripper is connected to a catalyst regeneration system via a second catalyst delivery pipe, and the catalyst regeneration system is connected to the bottom of the fluidized bed reactor via a regenerator delivery pipe.

[0009] Preferably, the reactor settling tank has a reactor outlet at the top and a reactor vortex separator below the reactor outlet; the stripper has a stripper gas inlet at the bottom.

[0010] Preferably, the catalyst regeneration system includes a regenerator settling tank, a regenerator, and a regenerator stripper connected in sequence from top to bottom; the second regenerator delivery pipe is connected to the regenerator, and the regenerator delivery pipe is connected to the bottom of the regenerator stripper.

[0011] More preferably, the top of the regenerator settling device is provided with a regeneration exhaust gas outlet, and a regenerator vortex separator is provided below the regeneration exhaust gas outlet.

[0012] More preferably, a heat exchanger is provided on the side of the regenerator; a regeneration air inlet is provided at the bottom of the regenerator, and a regeneration air distributor is provided above the regeneration air inlet.

[0013] More preferably, the bottom of the regenerant stripper is provided with a regenerant stripping gas inlet, and a regenerant stripping gas distributor is provided above the regenerant stripping gas inlet.

[0014] A method for producing ethylene from refinery dry gas using the above-mentioned apparatus includes the following steps:

[0015] S1 Feeding: Add catalyst and saturated dry gas from the first feed inlet, and add unsaturated dry gas from the second feed inlet. The catalyst-to-oil ratio is 5-30:1.

[0016] S2 reaction: The reaction temperature in the fluidized bed reactor is controlled at 400–750℃, the reaction pressure at 0.05–0.3 MPa, and the reaction time at 0.1–10 s;

[0017] S3 Catalyst Separation: After the reaction, the catalyst in the fluidized bed reactor enters the reactor settling tank for separation. The catalyst is deflected at the inclined baffle of the settling tank and moves towards the first feedstock delivery pipe, and then enters the feedstock stripper for further separation.

[0018] S4 catalyst regeneration: The catalyst separated by S3 enters the regeneration system through the second regenerator delivery pipe for regeneration. The regeneration temperature is controlled at 600-850℃ and the regeneration pressure is 0.05-0.3MPa. The regenerated catalyst is returned to the bottom of the fluidized bed reactor through the regenerator delivery pipe for recycling.

[0019] S5 Reaction Product Separation: The reaction products exiting the reactor outlet are separated to obtain ethylene, fuel gas and unreacted ethane. The temperature at the reactor outlet is controlled at 400-750℃. The unreacted ethane enters the first feed inlet to continue the reaction.

[0020] Preferably, the catalyst described in S1 comprises, by mass percentage, the following substances:

[0021]

[0022] Wherein, the SrCoO 3-x x is 0 to 0.5; the carrier is one or more selected from boehmite, alumina sol and silica sol.

[0023] More preferably, the catalyst described in S1 consists of the following substances by mass percentage:

[0024]

[0025] Preferably, the agent-to-oil ratio in S1 is 10–20:1; the reaction temperature in S2 is 500–700°C, the reaction pressure is 0.1–0.2 MPa, and the reaction time is 2.0–7.0 s; the regeneration temperature in S4 is 650–800°C, and the regeneration pressure is 0.1–0.2 MPa; and the temperature of reactor outlet 5 in S5 is 500–700°C.

[0026] More preferably, the method for preparing the catalyst includes the following steps:

[0027] (1) Dissolve the active component precursor fully in deionized water, then add solid acid and alcohol solvent, stir at high speed in a water bath at 60-80℃ until the mixture loses fluidity, then sonicate for 1-10 minutes, and then let it stand at room temperature to age until a wet gel is formed.

[0028] (2) The wet gel obtained in step (1) is dried at 90-120℃ for 20 min-20 h, then calcined at 180-340℃ for 2-5 h, and then calcined at 800-1000℃ for 4-12 h to obtain powder; the obtained powder is ground and sieved to obtain active components.

[0029] (3) Add the carrier precursor to deionized water, stir, then add the co-active component precursor and the active component obtained in step (2), stir thoroughly and homogenize for 0.5 to 4 hours to obtain a mixed slurry; spray dry the obtained mixed slurry to form a shape, and then dry and calcine the formed material to obtain the catalyst.

[0030] It is understandable that the above technical solutions are used to obtain perovskite-like metal oxide SrCoO 3-x The molar ratio of the active component precursor based on the metal elements (Sr, Co) is 1:1; the support precursor is prepared according to the mass content of oxides (Al2O3, SiO2) in the catalyst being 15-45%; and the co-active component precursors are added according to the mass content of Ba oxide in the catalyst being 2-15%, Mn oxide in the catalyst being 2-15%, and P oxide in the catalyst being 1-4%.

[0031] More preferably, in step (1), the solid acid is one or more of oxalic acid and citric acid, preferably citric acid; the alcohol solvent is one or more of ethanol and ethylene glycol, preferably ethylene glycol; even more preferably, the molar ratio of citric acid to cobalt / strontium metal ions is 1 to 4:1, and the molar ratio of ethylene glycol to citric acid is 1 to 4:1.

[0032] More preferably, in step (1), the high-speed mixer speed is 700-2000 r / min; the ultrasonic oscillation frequency is 30-55 kHz.

[0033] In the above technical solutions, high-speed stirring can accelerate water evaporation and shorten the conversion process from sol to gel; appropriate ultrasonic oscillation is beneficial for the dispersion of colloidal particles, control of appropriate grain size, and reduction of particle aggregation.

[0034] More preferably, the particle size of the powder obtained in step (1) is 15-40 nm; the active component is composed of powder with a particle size of 2000-3000 mesh.

[0035] In the above technical solution, the appropriate crystal size (15-40nm) of the main active component is conducive to the transfer of lattice oxygen and increases the catalyst activity; the microsphere catalyst prepared by spray drying of the main active component with a sieve range of 2000-3000 mesh has a good particle size distribution and is particularly suitable for fluidized bed reaction and regeneration systems.

[0036] More preferably, the drying conditions in step (2) are: first drying at 90℃, 100℃ and 110℃ for 20 min to 1 h, and then drying at 120℃ for 2 to 8 h; the heating rate in the calcination process of step (2) is 1 to 5℃ / min.

[0037] More preferably, in step (3), the temperature of the spray drying furnace is 340-460°C, the temperature of the drying tower outlet is 140-240°C, and the pressure is 2.2-4.0 MPa; the drying conditions for the molding material are: drying at 110-130°C for 2-5 hours, and the calcination conditions are: heating to 800-1000°C at a rate of 1-5°C / min and holding for 4-6 hours.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] (1) The inclined baffle of the settler of the present invention is set above the reactor and the right end of the baffle extends into the first pre-fermentation agent delivery pipe. This can accurately control the direction of the catalyst and make the reaction gas and the catalyst quickly separate and enter the first pre-fermentation agent delivery pipe, thereby shortening the contact time between the catalyst and the reaction gas, avoiding the reaction gas from being over-oxidized, thereby improving product selectivity. At the same time, the separate setting of the pre-fermentation agent stripper and the settler further shortens the residence time of the reaction products in the reactor, thereby reducing secondary reactions and increasing product yield.

[0040] (2) In this invention, saturated dry gas and / or unreacted recycled ethane enter from the first feed port, and ethylene-containing unsaturated dry gas enters from the second feed port. Thus, the raw materials do not need to be purified and separated, which can improve the adaptability of the device to the raw materials and reduce the separation energy consumption. At the same time, the catalyst activity above the second feed port is low. The reaction of ethylene-containing unsaturated dry gas entering from the second feed port can avoid the excessive oxidation reaction of ethylene, further improve the conversion rate of ethylene, and save energy consumption.

[0041] (3) The present invention enables the device to efficiently and continuously produce ethylene from dry gas by circulating the reaction gas and regenerating the catalyst, thereby achieving the goals of low carbon, energy saving, high efficiency and environmental protection.

[0042] (4) This invention enables the efficient production of ethylene from refinery dry gas in the device of this invention through the action of a catalyst and under specific conditions. The catalyst of this invention has superior reactivity, ethylene selectivity and stability, as well as superior particle size distribution and wear resistance, and is particularly suitable for circulating fluidized bed reaction regeneration cycle processes; the active component SrCoO 3-x It belongs to the hexagonal crystal system, with unit cell parameters a = 5.485, b = 5.485. The particles are uniformly distributed and the surface exhibits a large-pore honeycomb structure. Compared to the ABO3-type perovskite structure that satisfies typical stoichiometry, SrCoO...3-x It is oxygen-deficient, and this lack of oxygen gives it a unique type of lattice oxygen and a suitable rate of lattice oxygen transfer and release. Specifically, in the reaction process of this invention, it manifests as high ethylene selectivity. Barium oxide reacts with H2O generated from the in-situ combustion of hydrogen to form Ba(OH)2, which further promotes the reaction equilibrium and increases the ethane conversion rate. At the same time, manganese oxide increases the lattice oxygen reserve on the one hand, and improves the ethane conversion rate on the other. In addition, P oxide prevents water vapor from affecting the specific surface area and pore volume of the catalyst support at high temperatures. Furthermore, the appropriate addition of P will form AlPO4 on the surface of the support, weakening the force of the support on the active components and ensuring the activity stability of the catalyst. The support can effectively disperse the active components, weaken the aggregation of active components at high temperatures, ensure the effective diffusion of raw materials and products, and increase the catalyst's wear resistance. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of an apparatus for producing ethylene from refinery dry gas according to the present invention.

[0044] Figure 2 This is a flowchart of a method for producing ethylene from refinery dry gas according to the present invention.

[0045] The attached diagram is labeled as follows: 1-First feed inlet; 2-Second feed inlet; 3-Fluidized bed reactor; 4-Settler baffle; 5-Reactor outlet; 6-Reactor vortex separator; 7-Reactor settler; 8-First regenerator delivery pipe; 9-Regenerator stripper; 10-Regeneration tail gas outlet; 11-Regenerator vortex separator; 12-Regenerator settler; 13-Heat exchanger; 14-Regenerator; 15-Regeneration air inlet; 16-Regenerator stripper; 17-Regeneration stripper gas distributor; 18-Regenerator stripper gas inlet; 19-Regenerator delivery pipe; 20-Regeneration air distributor; 21-Second regenerator delivery pipe; 22-Regenerator stripper gas inlet. Detailed Implementation

[0046] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. Of course, the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0047] Although the steps in this invention are arranged by reference numerals, this is not intended to limit the order of the steps. Unless the order of the steps is explicitly stated or the execution of a step requires other steps as a basis, the relative order of the steps can be adjusted. It is understood that the term "and / or" as used herein refers to and covers any and all possible combinations of one or more of the associated listed items.

[0048] This invention utilizes the reaction of lattice oxygen from a redox catalyst with hydrogen generated from the dehydrogenation of ethane to produce water. Removing the hydrogen from the reaction zone promotes the forward equilibrium of the reaction, increasing ethylene selectivity. The process for producing ethylene from ethane using CL-ODH with an oxide of metal Co as an example is as follows:

[0049] Reaction: C2H6 + Co3O4 = C2H4 + H2O + 3CoO ΔH 750℃ =101.4 kJ / mol

[0050] Regeneration: 3CoO+1 / 2O2=Co3O4ΔH 750℃ = -205.3 kJ / mol

[0051] In this process, the in-situ combustion of hydrogen not only provides heat for the reaction itself but also promotes reaction equilibrium, reduces the yield of non-condensable gases, and lowers downstream separation costs. This represents a low-carbon, efficient, and environmentally friendly technological approach. Developing a continuous, efficient, and energy-saving dry gas chemical epoxidation dehydrogenation reaction regeneration technology for ethylene production is crucial for improving the economic benefits of refineries.

[0052] The process of this invention is as follows:

[0053] S1 Feeding: Add catalyst and dry gas to the fluidized bed reactor. The catalyst-to-oil ratio is 5-30:1. For example, the catalyst-to-oil ratio can be 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, 16:1, 17:1, 18:1, 19:1, 20:1, 21:1, 22:1, 23:1, 24:1, 25:1, 26:1, 27:1, 28:1, 29:1, or 30:1.

[0054] S2 reaction: The reaction temperature in the fluidized bed reactor is controlled at 400–750℃, for example, the reaction temperature can be 400℃, 450℃, 500℃, 550℃, 600℃, 650℃, 700℃, or 750℃; the reaction pressure is controlled at 0.05–0.3 MPa, for example, the reaction pressure can be 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, or 0.3 MPa; the reaction time is 0.1–10 minutes. For example, the reaction time can be 0.1s, 0.3s, 0.5s, 1.0s, 1.5s, 1.7s, 2s, 2.3s, 2.6s, 3s, 3.5s, 3.8s, 4s, 4.2s, 4.7s, 5s, 5.1s, 5.6s, 6s, 6.5s, 6.8s, 7s, 7.2s, 7.6s, 7.9s, 8s, 8.2s, 8.5s, 8.8s, 9s, 9.5s, 9.7s, or 10s.

[0055] S3 Catalyst Separation: After the reaction, the catalyst in the fluidized bed reactor enters the reactor settling tank for separation;

[0056] S4 Catalyst Regeneration: The catalyst separated in S3 enters the regeneration system for regeneration. The regeneration temperature is controlled at 600–850℃, for example, 600℃, 650℃, 700℃, 750℃, 800℃, and 850℃; the regeneration pressure is 0.05–0.3 MPa, for example, 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.25 MPa, and 0.3 MPa; the regenerated catalyst is returned to the bottom of the fluidized bed reactor for recycling.

[0057] S5 Reaction Product Separation: The reaction products exiting the reactor are separated to obtain ethylene, fuel gas, and unreacted ethane. The reactor outlet temperature is controlled at 400–750°C, for example, the reactor outlet temperature can be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, or 750°C. The unreacted ethane is returned to the fluidized bed reactor to continue the reaction.

[0058] The catalyst, by mass percentage, comprises the following substances:

[0059]

[0060] perovskite-like metal oxide SrCoO 3-x The proportions of the following components can be, for example, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, and 80%; the proportions of barium oxide can be, for example, 2%, 3%, 4%, 5%, 6%, 7%, and 8%; the proportions of manganese oxide can be, for example, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, and 15%; the proportions of phosphorus oxide can be, for example, 1%, 2%, 3%, and 4%; and the proportions of the support can be, for example, 15%, 20%, 25%, 30%, 35%, 40%, and 45%. The SrCoO 3-x The x in the figure is 0 to 0.5, and x can be, for example, 0, 0.05, 0.1, 0.17, 0.2, 0.23, 0.25, 0.3, 0.36, 0.38, 0.4, 0.43, 0.48, or 0.5; the carrier is one or more selected from boehmite, alumina sol, and silica sol.

[0061] Specifically, the catalyst of this invention is microspheres with physical properties satisfying the following: bulk density of 0.8–1.5 kg / m³. 3 Specific surface area is 10-20 m² 2 / g, abrasion index less than 3.0%.

[0062] Specifically, the particle size distribution of the catalyst described in this invention satisfies the following conditions: particles <20μm account for no more than 7%, and particles >149μm account for no more than 8%.

[0063] The method for preparing the catalyst includes the following steps:

[0064] (1) Dissolve the active component precursor fully in deionized water, then add solid acid and alcohol solvent, stir at high speed in a water bath at 60-80℃ until the mixture loses fluidity, then sonicate for 1-10 minutes, and then let it stand at room temperature to age until a wet gel is formed.

[0065] (2) The wet gel obtained in step (1) is dried at 90-120℃ for 20 min-20 h, then calcined at 180-340℃ for 2-5 h, and then calcined at 800-1000℃ for 4-12 h to obtain powder; the obtained powder is ground and sieved to obtain active components.

[0066] (3) Add the carrier precursor to deionized water, stir, then add the co-active component precursor and the active component obtained in step (2), stir thoroughly and homogenize for 0.5 to 4 hours to obtain a mixed slurry; spray dry the obtained mixed slurry to form a shape, and then dry and calcine the formed material to obtain the catalyst.

[0067] Specifically, the precursor of the active component is a soluble salt containing Sr and Co; the precursor of the co-active component is a soluble salt or acid containing Ba, Mn, and P.

[0068] Specifically, in step (1), the solid acid is one or more of oxalic acid and citric acid, preferably citric acid; the alcohol solvent is one or more of ethanol and ethylene glycol, preferably ethylene glycol; the molar ratio of citric acid to cobalt / strontium metal ions is 1 to 4:1, and the molar ratio of ethylene glycol to citric acid is 1 to 4:1.

[0069] Specifically, in step (1), the speed of the high-speed mixer is 700-2000 r / min, preferably 1000 r / min; the ultrasonic oscillation frequency is 30-55 kHz.

[0070] In the above technical solutions, high-speed stirring can accelerate water evaporation and shorten the conversion process from sol to gel; appropriate ultrasonic oscillation is beneficial for the dispersion of colloidal particles, control of appropriate grain size, and reduction of particle aggregation.

[0071] Specifically, the particle size of the powder obtained in step (1) is 15-40 nm; the active component is composed of powder with a particle size of 2000-3000 mesh.

[0072] In the above technical solution, the appropriate crystal size (15-40nm) of the main active component is conducive to the transfer of lattice oxygen and increases the catalyst activity; the microsphere catalyst prepared by spray drying of the main active component with a sieve range of 2000-3000 mesh has a good particle size distribution and is particularly suitable for fluidized bed reaction and regeneration systems.

[0073] Specifically, the drying conditions in step (2) are as follows: first, dry at 90℃, 100℃ and 110℃ for 20 min to 1 h, and then dry at 120℃ for 2 to 8 h; the heating rate in the roasting process of step (2) is 1 to 5℃ / min.

[0074] Specifically, in step (3), the temperature of the spray drying furnace is 340-460℃, the temperature of the drying tower outlet is 140-240℃, and the pressure is 2.2-4.0MPa; the drying conditions for the molding material are: drying at 110-130℃ for 2-5 hours, and the calcination conditions are: heating to 800-1000℃ at a rate of 1-5℃ / min and holding for 4-6 hours.

[0075] Example 1

[0076] An apparatus for producing ethylene from refinery dry gas includes a fluidized bed reactor 3, wherein a first feed inlet 1 is provided at the bottom of the fluidized bed reactor 3, and a second feed inlet 2 is provided in the middle of the fluidized bed reactor 3; the top of the fluidized bed reactor 3 is connected to the bottom left side of a reactor settling tank 7, and the bottom right side of the reactor settling tank 7 is connected to the top of a settling tank stripper 9 through a first pre-regenerating agent conveying pipe 8; the left inner sidewall of the reactor settling tank 7 is provided with a settling tank inclined baffle 4 that slopes downward to the right, and the right end of the settling tank inclined baffle 4 is bent downward and extends into the first pre-regenerating agent conveying pipe 8; the bottom of the pre-regenerating agent stripper 9 is connected to a catalyst regeneration system through a second pre-regenerating agent conveying pipe 21, and the catalyst regeneration system is connected to the bottom of the fluidized bed reactor 3 through a regenerating agent conveying pipe 19.

[0077] In this embodiment, the reactor settling tank 7 is provided with a reactor outlet 5 at the top, and a reactor vortex separator 6 is provided below the reactor outlet 5; the scavenger stripper 9 is provided with a scavenger stripper gas inlet 22 at the bottom.

[0078] In this embodiment, the catalyst regeneration system includes a regenerator settling tank 12, a regenerator 14, and a regenerator stripper 16 connected sequentially from top to bottom; the second regenerator delivery pipe 21 is connected to the regenerator 14, and the regenerator delivery pipe 19 is connected to the bottom of the regenerator stripper 16.

[0079] In this embodiment, the top of the regenerator settling device 12 is provided with a regeneration exhaust gas outlet 10, and the bottom of the regeneration exhaust gas outlet 10 is provided with a regenerator vortex separator 11.

[0080] In this embodiment, a heat exchanger 13 is provided on the side of the regenerator 14; a regeneration air inlet 15 is provided at the bottom of the regenerator 14, and a regeneration air distributor 20 is provided above the regeneration air inlet 15.

[0081] In this embodiment, the bottom of the regenerant stripper 16 is provided with a regenerant stripping gas inlet 18, and the top of the regenerant stripping gas inlet 18 is provided with a regenerant stripping gas distributor 17.

[0082] A method for producing ethylene from refinery dry gas using the above-mentioned apparatus includes the following steps:

[0083] S1 Feeding: Add catalyst through the first feed port 1 and add unsaturated dry gas through the second feed port 2. The unsaturated dry gas composition is 4.0 wt% hydrogen, 36.1 wt% methane, 38.1 wt% ethylene and 21.8 wt% ethane. The feed rate of unsaturated dry gas is 100 kg / h and the catalyst-to-oil ratio is 15:1.

[0084] S2 reaction: The reaction temperature of fluidized bed reactor 3 is controlled at 650℃, the reaction pressure at 0.1 MPa, and the reaction time at 5 s;

[0085] S3 Catalyst Separation: After the reaction, the catalyst in the fluidized bed reactor 3 enters the reactor settling tank 7 for separation. The catalyst is deflected at the inclined baffle 4 of the settling tank and moves to the first raw material conveying pipe 8, and then enters the raw material stripper 9 for further separation.

[0086] S4 Catalyst Regeneration: The catalyst separated by S3 enters the regeneration system through the second regenerator delivery pipe 21 for regeneration. The regeneration temperature is controlled at 750℃ and the regeneration pressure is 0.1MPa. The regenerated catalyst returns to the bottom of the fluidized bed reactor 3 through the regenerator delivery pipe 19 for recycling.

[0087] S5 Reaction Product Separation: The reaction products exiting reactor outlet 5 are separated to obtain ethylene, fuel gas and unreacted ethane. The temperature of reactor outlet 5 is controlled at 650℃, and the unreacted ethane enters the first feed inlet 1 to continue the reaction.

[0088] In this embodiment, the catalyst described in S1 consists of the following substances by mass percentage:

[0089]

[0090] The method for preparing the catalyst includes the following steps:

[0091] (1) Dissolve 163.5g of cobalt nitrate hexahydrate and 118.9g of strontium nitrate in 550mL of deionized water and stir until fully mixed; then add 283g of citric acid and 126g of ethylene glycol, and stir fully in a 70℃ water bath at 1000r / min until the mixture loses its fluidity. Then sonicate at 60℃ and 35kHz for 5min, and then let it stand at room temperature to age until a wet gel is formed.

[0092] (2) The wet gel obtained in step (1) was dried at 90℃, 100℃ and 110℃ for 40 min in sequence, and then dried at 120℃ for 6 h to obtain a dry gel. The dry gel was heated to 280℃ in a muffle furnace at a rate of 2℃ / min and held for 2 h, and then heated to 880℃ at a rate of 2℃ / min and held for 6 h to obtain a powder. The obtained powder was ground and sieved using a ball mill, and the powder with a sieve range of 2000 to 3000 mesh was taken as active component #1.

[0093] (3) Add 172g of aluminum sol to 200mL of deionized water, and while stirring, add 13.1g of barium nitrate, 31.7g of 50% manganese nitrate aqueous solution, 3.7g of ammonium dihydrogen phosphate and 100g of active component #1 obtained in step (1). Stir thoroughly and homogenize for 1.5h to obtain a mixed slurry. Spray dry the obtained mixed slurry to form a shape (spray drying furnace temperature is 410℃, drying tower outlet temperature is 180℃, pressure is 3.3MPa). Then dry the formed material at 120℃ for 3h, and then raise the temperature to 880℃ at a rate of 3℃ / min and hold for 4h to obtain the catalyst C1 of the present invention.

[0094] Example 2:

[0095] The apparatus used in Example 2 is the same as that in Example 1. The method for producing ethylene from refinery dry gas using the apparatus includes the following steps:

[0096] S1 Feeding: Add catalyst through the first feed port 1 and add unsaturated dry gas through the second feed port 2. The unsaturated dry gas composition is 4.0 wt% hydrogen, 36.1 wt% methane, 38.1 wt% ethylene and 21.8 wt% ethane. The feed rate of unsaturated dry gas is 100 kg / h and the catalyst-to-oil ratio is 18:1.

[0097] S2 reaction: The reaction temperature of fluidized bed reactor 3 is controlled at 680℃, the reaction pressure at 0.15 MPa, and the reaction time at 4 s;

[0098] S3 Catalyst Separation: After the reaction, the catalyst in the fluidized bed reactor 3 enters the reactor settling tank 7 for separation. The catalyst is deflected at the inclined baffle 4 of the settling tank and moves to the first raw material conveying pipe 8, and then enters the raw material stripper 9 for further separation.

[0099] S4 Catalyst Regeneration: The catalyst separated by S3 enters the regeneration system through the second regenerator delivery pipe 21 for regeneration. The regeneration temperature is controlled at 780℃ and the regeneration pressure is 0.15MPa. The regenerated catalyst returns to the bottom of the fluidized bed reactor 3 through the regenerator delivery pipe 19 for recycling.

[0100] S5 Reaction Product Separation: The reaction products exiting reactor outlet 5 are separated to obtain ethylene, fuel gas and unreacted ethane. The temperature of reactor outlet 5 is controlled at 600℃, and the unreacted ethane enters the first feed inlet 1 to continue the reaction.

[0101] In this embodiment, the catalyst described in S1 consists of the following substances by mass percentage:

[0102]

[0103] Comparative Example 1

[0104] The method used in Comparative Example 1 is the same as that in Example 1, except that the device used does not have a second feed inlet 2 and a settling device baffle 4, and the oxidant stripper 9 is located inside the reactor settling device 7, with unsaturated dry gas entering from the first feed inlet 1.

[0105] Comparative Example 2

[0106] Comparative Example 2 illustrates a method for preparing a catalyst, comprising the following steps:

[0107] (1) The preparation conditions and composition of the active components are the same as those of active component #1 in Example 1. The difference is that the sieving range of the powder is controlled between 1000 and 2000 mesh to obtain active component #3.

[0108] (2) Add 109g of aluminum sol to 180mL of deionized water, and while stirring, add 11.8g of barium nitrate, 28.6g of 50% manganese nitrate aqueous solution, 3.4g of ammonium dihydrogen phosphate and 100g of active component #3 obtained in step (1). Stir thoroughly and homogenize for 1.5h to obtain a mixed slurry. Spray dry the obtained mixed slurry to form a shape (spray drying furnace temperature is 410℃, drying tower outlet temperature is 180℃, and pressure is 3.3MPa). Then dry the formed material at 120℃ for 3h, and then raise the temperature to 880℃ at a rate of 3℃ / min and hold for 4h to obtain the catalyst C9 of the present invention.

[0109] The yields of ethylene after the reaction in Examples 1-2 and Comparative Example 1 were determined using dry gas with the same feed rate and concentration, as shown in Table 1.

[0110] Table 1 Comparison of Ethylene Production

[0111] Dry gas feed rate, kg / h Ethylene production, kg / h Example 1 100 54.5 Example 2 100 54.9 Comparative Example 1 100 41.0

[0112] Under the same dry gas feed rate, the catalysts prepared in Examples 1-2 of the present invention have higher ethylene production. Meanwhile, comparing the energy consumption of Example 1 and Comparative Example 1, the energy consumption required for Example 1 to produce the same amount of ethylene is 0.75 times that required for Comparative Example 1.

[0113] The specific physical properties of the catalysts prepared in Example 1 and Comparative Example 2 are shown in Table 2:

[0114] Table 2 Physical properties of the catalyst

[0115] Catalyst number C1 C9 Bulk density, kg / m3 1.1 1.05 Specific surface area, m2 / g 13.5 12.8 Wear index, % 2.2 2.9 Particle size distribution, % <20μm 6.1 6.5 >149μm 6.2 15.1

[0116] Metal oxides generally have a low specific surface area (<5m²) after high-temperature calcination. 2 / g); however, as can be seen from Table 2, the catalyst prepared by the method provided by the present invention has a relatively high specific surface area; at the same time, the catalyst of the present invention also has good wear resistance; the catalyst of the present invention has a better sieving range, and is especially suitable for circulating fluidized bed reaction regeneration systems; the catalyst C1 prepared in Example 1 of the present invention has a better particle size distribution than the catalyst C9 prepared in Comparative Example 2.

[0117] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the inventive concept of the present invention, and these all fall within the protection scope of the present invention.

Claims

1. A method for producing ethylene from refinery dry gas, characterized in that, Includes the following steps: S1 Feeding: Add catalyst and saturated dry gas from the first feed inlet (1), and add unsaturated dry gas from the second feed inlet (2). The catalyst-to-oil ratio is 5-30:

1. S2 reaction: The reaction temperature of the fluidized bed reactor (3) is controlled at 400-750℃, the reaction pressure at 0.05-0.3 MPa, and the reaction time at 0.1-10 s; S3 Catalyst Separation: After the reaction, the catalyst in the fluidized bed reactor (3) enters the reactor settling tank (7) for separation. The catalyst is deflected at the settling tank baffle (4) and moves to the first feedstock delivery pipe (8), and then enters the feedstock stripper (9) for further separation. S4 catalyst regeneration: The catalyst separated by S3 enters the regeneration system through the second regenerator conveying pipe (21) for regeneration. The regeneration temperature is controlled at 600-850℃ and the regeneration pressure is 0.05-0.3MPa. The regenerated catalyst returns to the bottom of the fluidized bed reactor (3) through the regenerator conveying pipe (19) for recycling. S5 reaction product separation: The reaction products coming out of the reactor outlet (5) are separated to obtain ethylene, fuel gas and unreacted ethane. The temperature of the reactor outlet (5) is controlled at 400-750℃. The unreacted ethane enters the first feed inlet (1) to continue the reaction. The catalyst described in S1 consists of the following substances by mass percentage: Wherein, the SrCoO 3-x x is 0 to 0.5; the carrier is one or more selected from boehmite, alumina sol and silica sol; The apparatus includes a fluidized bed reactor (3), with a first feed inlet (1) at the bottom and a second feed inlet (2) at the middle. The top of the fluidized bed reactor (3) is connected to the bottom left side of the reactor settling tank (7), and the bottom right side of the reactor settling tank (7) is connected to the top of the settling tank stripper (9) via a first pre-treatment agent conveying pipe (8). The left inner sidewall of the reactor settling tank (7) is provided with a settling tank inclined baffle (4) that slopes downward to the right, and the right end of the settling tank inclined baffle (4) bends downward and extends into the first pre-treatment agent conveying pipe (8). The bottom of the settling tank stripper (9) is connected to the catalyst regeneration system via a second pre-treatment agent conveying pipe (21), and the catalyst regeneration system is connected to the bottom of the fluidized bed reactor (3) via a regenerator conveying pipe (19). The reactor settling device (7) has a reactor outlet (5) at the top and a reactor vortex separator (6) below the reactor outlet (5); the reactor stripper (9) has a reactor stripper gas inlet (22) at the bottom.

2. The method according to claim 1, characterized in that, The catalyst regeneration system includes a regenerator settling tank (12), a regenerator (14), and a regenerator stripper (16) connected in sequence from top to bottom; the second regenerator delivery pipe (21) is connected to the regenerator (14), and the bottom of the regenerator delivery pipe (19) is connected to the regenerator stripper (16).

3. The method according to claim 2, characterized in that, The top of the regenerator settling device (12) is provided with a regeneration exhaust gas outlet (10), and a regenerator vortex separator (11) is provided below the regeneration exhaust gas outlet (10).

4. The method according to claim 2, characterized in that, The regenerator (14) has a heat exchanger (13) on its side; the regenerator (14) has a regeneration air inlet (15) at its bottom, and a regeneration air distributor (20) is provided above the regeneration air inlet (15).

5. The method according to claim 2, characterized in that, The bottom of the regenerator stripper (16) is provided with a regenerator stripping gas inlet (18), and a regenerator stripping gas distributor (17) is provided above the regenerator stripping gas inlet (18).

6. The method according to claim 1, characterized in that, The catalyst described in S1 consists of the following substances by mass percentage:

7. The method according to claim 1, characterized in that, The agent-to-oil ratio in S1 is 10-20:1; the reaction temperature in S2 is 500-700℃, the reaction pressure is 0.1-0.2 MPa, and the reaction time is 2.0-7.0 s; the regeneration temperature in S4 is 650-800℃, and the regeneration pressure is 0.1-0.2 MPa; the temperature of the reactor outlet (5) in S5 is 500-700℃.

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