Hybrid olefin conversion apparatus and conversion method thereof

Abstract

The application discloses a mixed olefin conversion device and a conversion method thereof. The process flow adopts an integrated rectification-reaction-stage cooling-phase separation sequential circulation operation. The mixed olefin conversion device is a circulation reaction device, and comprises a rectification unit, a reaction unit and a cooling separation unit which are sequentially connected. The rectification unit comprises a rectification tower, and the rectification tower comprises a feeding end and a separation end. The reaction unit comprises a reactor. The cooling separation unit is a two-stage gas-liquid phase separation unit, and comprises a first-stage gas-liquid phase separation device and a second-stage gas-liquid phase separation device which are sequentially connected. The method can be used for the continuous production of 2-butene from mixed carbon four olefins, avoids the method of adding an etherification unit to separate isobutene in a traditional process, is simple in process flow, easy to operate and low in production cost.

Description

Technical Field

[0001] This application relates to a mixed olefin conversion device and its conversion method, belonging to the field of chemical technology. Background Technology

[0002] Isobutylene is a typical C4 byproduct in the petroleum refining industry, mainly used in oil blending and the synthesis of methyl tert-butyl ether (MTBE) to produce butyl rubber, methacrylonitrile, and antioxidants, among other chemical products. Market demand is limited. Meanwhile, with the rise of emerging industries such as ethanol biofuels and the promotion of ethanol gasoline, oxygen-containing compounds like MTBE can no longer be used as gasoline additives, further shrinking the market demand for isobutylene. Developing new downstream derivative production processes for isobutylene has become an urgent issue to address.

[0003] Chinese patent application CN112441865 discloses a method for preparing n-butene from isobutene. The method employs a two-step hydrogen-free reaction, first converting isobutene into butene-1 intermediate, and then isomerizing butene-1 into butene-2.

[0004] Chinese patent application CN112441866 discloses a method for preparing n-butene from isobutene. The method introduces an etherification reaction and separation device to purify isobutene from C4 feedstock, and then generates n-butene product through hydrogen-free isomerization.

[0005] Chinese patent application CN108997075 discloses a method for isobutene isomerization, which uses the product of hydrotalcite calcination as a support to support a platinum group metal synthetic isomer catalyst, achieving a target product selectivity of 99.87% and a maximum yield of n-butene of 47.28%.

[0006] The inventions described above all explored the production of n-butene from isobutene, with the main focus being catalyst development. However, the process design did not consider carrier gas separation and reuse. Summary of the Invention

[0007] This invention provides a method for converting mixed olefins, which integrates distillation to pretreat raw materials and reaction byproducts, and simultaneously achieves carrier gas separation and recovery through two-stage condensation separation, thereby simplifying the production process and reducing production costs.

[0008] One aspect of this application provides a mixed olefin conversion apparatus, which is a circulating reaction apparatus comprising a distillation unit, a reaction unit, and a cooling and separation unit connected in sequence.

[0009] The distillation unit includes a distillation column, which includes a feed end and a separation end. The feed end includes inlet I, inlet II, and inlet III. The separation end includes a liquid phase separation outlet for light components and a liquid phase separation outlet for heavy components.

[0010] The reaction unit includes a reactor, which includes a reactor inlet I, a reactor inlet II, and a reaction product outlet.

[0011] The outlet of the light component liquid phase separator is connected to the reactor inlet I pipeline;

[0012] The cooling separation unit is a two-stage gas-liquid phase separation unit, comprising a cooling device I, a first-stage gas-liquid phase separation device, a cooling device II, and a second-stage gas-liquid phase separation device connected in sequence.

[0013] The first-stage gas-liquid phase separation device is provided with a first inlet, a gas phase outlet I, and a liquid phase outlet I; the second-stage gas-liquid phase separation device is provided with a second inlet, a gas phase outlet II, and a liquid phase outlet II.

[0014] The reaction product outlet, cooling device I, and first inlet are connected in sequence by pipelines; the gas phase outlet I, cooling device II, and second inlet are connected in sequence by pipelines; the gas phase outlet II is connected to the reactor inlet II by pipeline; the liquid phase outlet I and liquid phase outlet II are respectively connected to the raw material inlet I and raw material inlet II by pipelines.

[0015] The mixed olefin conversion unit is also equipped with a hydrogen supply end; the hydrogen supply end is connected to the reactor inlet II pipeline.

[0016] Optionally, the separation end is provided with a light component gas phase outlet;

[0017] The distillation column is equipped with a condenser at the top;

[0018] The distillation column is also equipped with raw material inlet III;

[0019] The distillation unit also includes a pressurization device I.

[0020] Optionally, the pressurization device I is installed on the connecting pipeline between the outlet of the light component liquid phase separator and the inlet I of the reactor.

[0021] Optionally, the distillation column has 30 to 110 theoretical plates;

[0022] Optionally, the upper limit of the theoretical number of plates in the distillation column can be independently selected from 45, 65, 85, 100, or 110 plates; the lower limit can be independently selected from 30, 45, 65, 85, or 100 plates.

[0023] Optionally, the reflux ratio of the distillation column is 5 to 60.

[0024] Optionally, the reaction unit further includes preheater I and preheater II;

[0025] The distillation column, preheater I, and reactor inlet I are sequentially connected by pipelines.

[0026] The preheater II is located on the inlet pipe of the reactor inlet II.

[0027] Optionally, the reaction unit further includes a preheater I;

[0028] The preheater I is connected to the reactor inlet I and the pressurization device I via pipelines.

[0029] Optionally, the cooling device I is a water-cooling device;

[0030] The cooling device II is a cryogenic device.

[0031] Optionally, the separation unit further includes a pressurization device II; the gas phase outlet II, the pressurization device II, and the reactor inlet II are connected in sequence by pipelines.

[0032] Another aspect of this application provides a method for converting mixed olefins, the method comprising: feeding a feedstock containing mixed C4 olefins into a reaction apparatus containing a catalyst through inlet III, and reacting to obtain a product containing 2-butene;

[0033] The reaction apparatus is selected from the above-mentioned mixed olefin conversion apparatus.

[0034] Optionally, the specific steps include:

[0035] (1) The raw material containing mixed C4 olefins is fed into the distillation column through inlet III to separate and produce light component gas phase, light component liquid phase and heavy component liquid phase;

[0036] The light component gas phase is discharged through the light component gas phase outlet, the heavy component liquid phase is discharged through the heavy component liquid phase separator outlet, and the light component liquid phase enters the reactor through the light component liquid phase separator outlet.

[0037] The light component gas phase includes a mixture of light wastes such as butene, methane, and ethylene;

[0038] The light component liquid phase includes isobutylene and 1-butene;

[0039] The recombinant liquid phase is a 2-butene product with a mass fraction greater than 85%;

[0040] (2) The light component liquid phase entering the reactor reacts with the hydrogen gas entering the reactor through reactor inlet II to obtain the reaction product;

[0041] The reactor contains a catalyst;

[0042] The reaction product is a normal reaction product;

[0043] (3) The reaction products are separated into gas phase I and liquid phase I by the first-stage gas-liquid phase separation device; gas phase I enters the second-stage gas-liquid phase separation device through gas phase outlet I for secondary cooling and separation, and gas phase II and liquid phase II are separated.

[0044] The gas phase II enters the reactor through the gas phase outlet II and the reactor inlet II;

[0045] The liquid phase I enters the distillation column sequentially through liquid phase outlet I and inlet I;

[0046] The liquid phase II enters the distillation column sequentially through liquid phase outlet II and inlet II;

[0047] (4) Liquid phase I and liquid phase II are mixed with the raw material containing mixed C4 olefins in the distillation column to obtain mixed raw material. The mixed raw material is then distilled in the distillation column to separate heavy component liquid phase, light component liquid phase and light component gas phase.

[0048] Liquid phase I and liquid phase II are isobutylene raw material and 2-butene product obtained by condensation, and contain a small amount of light component impurities;

[0049] Optionally, the operating pressure of the distillation column is 0.1–3.0 MPa;

[0050] Optionally, the upper limit of the operating pressure of the distillation column can be independently selected from 0.5MPa, 1MPa, 1.5MPa, 2MPa, 2.5MPa, and 3MPa; the lower limit can be independently selected from 0.1MPa, 0.5MPa, 1MPa, 1.5MPa, 2MPa, and 2.5MPa.

[0051] Optionally, the top temperature of the distillation column is -40 to 42°C;

[0052] Optionally, the upper limit of the top temperature of the distillation column can be independently selected from -30℃, -20℃, -10℃, 0℃, 10℃, 20℃, 30℃, and 42℃; the lower limit can be independently selected from -40℃, -30℃, -20℃, -10℃, 0℃, 10℃, 20℃, and 30℃.

[0053] Optionally, the cooling temperature of the first-stage gas-liquid phase separation device is 42–65°C;

[0054] Optionally, the upper limit of the cooling temperature of the first-stage gas-liquid phase separation device can be independently selected from 45℃, 50℃, 55℃, 60℃, and 65℃; the lower limit can be independently selected from 42℃, 45℃, 50℃, 55℃, and 60℃.

[0055] Optionally, the cooling temperature of the second-stage gas-liquid phase separation device is -60 to -10°C;

[0056] Optionally, the upper limit of the cooling temperature of the second-stage gas-liquid phase separation device can be independently selected from -50℃, -40℃, -30℃, -20℃, and -10℃; the lower limit can be independently selected from -60℃, -50℃, -40℃, -30℃, and -20℃.

[0057] Optionally, the liquid raw material is preheated by preheater I before entering the reactor;

[0058] The hydrogen gas is preheated by preheater II before entering the reactor.

[0059] Optionally, the catalytic reaction temperature is 250℃~600℃.

[0060] Optionally, the upper limit of the catalytic reaction temperature can be independently selected from 300℃, 400℃, 500℃, and 600℃; the lower limit can be independently selected from 250℃, 300℃, 400℃, and 500℃.

[0061] Optionally, the light component liquid phase is pressurized by pressurization device I before entering the reactor;

[0062] The hydrogen gas is pressurized by pressurization device II before entering the reactor.

[0063] In one specific embodiment, the mixed olefin conversion device includes the following components:

[0064] Main tower 1, feed pump 2, feed preheater 3, hydrogen preheater 4, ortho-structure reactor 5, cooler 6, cooling separator 7, cryogenic unit 8, cryogenic separator 9, circulating hydrogen compressor 10.

[0065] As one specific embodiment, the conversion method of the mixed olefins includes the following steps:

[0066] S001: The mixed C4 olefin feedstock is fed into the main tower 1. The gas phase at the top of the tower is light component non-condensable gas, the liquid phase at the top of the tower is isobutylene and 1-butene feedstock, and the bottom of the tower is 2-butene product.

[0067] The mixed butene feedstock extracted from the top of the main tower 1 of S00:2 is pressurized by the feedstock pump 2 and preheated to the reaction temperature in the feedstock preheater 3 and the hydrogen preheater 4, respectively.

[0068] S003: The preheated mixed butene raw material and hydrogen are sent to the ortho-reaction reactor 5, where the ortho-reaction product is obtained through catalytic reaction.

[0069] S004: The products of the normal reaction are cooled by cooler 6 and separated into gas and liquid phases, and gas-liquid separation is achieved in cooler separator 7.

[0070] S005: The gas phase separated by the cooling separator 7 is cryogenically cooled by the cryostat 8 and then separated into two phases. Gas-liquid phase separation is achieved in the cryogenic separator 9. The gas phase is then pressurized by the circulating hydrogen compressor 10 and recycled.

[0071] S006: The dehydrogenated liquid phase at the bottom of the cooling separator 7 and the cryogenic separator 9 is sent back to the main tower 1, where unreacted raw materials and 2-butene products with a mass fraction greater than 85% are separated by distillation.

[0072] The beneficial effects that this application can produce include:

[0073] This method can be used for the continuous production of 2-butene from mixed C4 olefins, avoiding the need for the traditional process of adding an etherification unit to separate isobutene. The process is simple, easy to operate, and reduces production costs. It also avoids multi-unit combined operations, simplifying the operational steps. Attached Figure Description

[0074] Figure 1 This is a schematic diagram of a mixed olefin conversion device according to Embodiment 1 of this application.

[0075] The components include: 1. Distillation column, 1-1. Light component liquid phase separator outlet, 1-2. Heavy component liquid phase separator outlet, 1-3. Light component gas phase outlet, 1-4. Inlet II, 1-5. Inlet I, 1-6. Inlet III; 2. Feed pump; 3. Feed preheater; 4. Hydrogen preheater; 5. Ortho-conversion reactor, 5-1. Reactor inlet I, 5-2. Reactor inlet II, 5-3. Reaction product outlet; 6. Cooler; 7. Cooling separator, 7-1. First inlet, 7-2. Liquid phase outlet I, 7-3. Gas phase outlet I; 8. Cryogenic separator; 9. Cryogenic separator, 9-1. Second inlet, 9-2. Liquid phase outlet II, 9-3. Gas phase outlet II; 10. Circulating hydrogen compressor. Detailed Implementation

[0076] The present application is described in detail below with reference to the embodiments, but the present application is not limited to these embodiments.

[0077] Unless otherwise specified, the raw materials and catalysts used in the embodiments of this application were all purchased commercially.

[0078] Example 1

[0079] One embodiment of this application includes a mixed olefin conversion device such as... Figure 1 As shown, it includes:

[0080] The light component liquid phase separation outlet 1-1 of the distillation column 1 is connected to the normalization reactor 5 through the feed pump 2 and the feed preheater 3. The reaction product outlet 5-3 of the normalization reactor 5 is connected to the cooling separator 7 (i.e., the first-stage gas-liquid phase separation device) through the cooler 6.

[0081] The gas phase outlet I7-3 of the cooling separator 7 is connected to the cryogenic separator 9 (i.e., the second-stage gas-liquid phase separation device) through the cryogenic cooler 8;

[0082] The liquid phase outlet I7-2 of the cooling separator 7 and the liquid phase outlet II9-2 of the cryogenic separator 9 are connected to the inlet I1-5 and the inlet II1-4 of the distillation column 1, respectively.

[0083] The gas phase outlet II9-3 of the cryogenic separator 9 is connected to the reactor 5 via the circulating hydrogen compressor 10 and the hydrogen preheater 4.

[0084] Example 2

[0085] A mixed C4 olefin feedstock containing 37% 1-butene, 26% 2-butene, 37% isobutene, and 10% ethylene, propylene, and methane (molar fractions) is fed into distillation column 1 along with recycled feedstock. Distillation column 1 operates at a pressure of 0.5 MPa and a top temperature of 42°C, and has 65 theoretical plates. A condenser is used at the top of distillation column 1. The top gas phase is a light-component non-condensable gas containing 80% mixed butene and 20% light waste such as methane and ethylene, which is discharged as waste gas. The top liquid phase is the reaction feedstock containing 49.7% wt of isobutene and 49.8% wt of 1-butene, and the bottom phase is the 2-butene product with a mass fraction greater than 85%. The mixed butene reaction feedstock collected from the top of main tower 1 is pressurized to 2.6 MPa by feedstock pump 2 and preheated to 270°C with the required hydrogen in feedstock preheater 3 and hydrogen preheater 4, respectively, before being sent to ortho-butene reactor 5. The ortho-butene product is obtained through catalytic reaction using a Pt-supported ZSM-5 molecular sieve catalyst, with a hydrogen to isobutene molar ratio of 2.8:1. The ortho-butene product is cooled to 42°C in cooler 6 and separates into vapor and liquid phases. Gas-liquid separation is achieved in cooling separator 7. The separated gas phase is cryogenically cooled to -30°C in cryogenic separator 8 and undergoes secondary phase separation, followed by gas-liquid separation in cryogenic separator 9. The gas phase is pressurized to 2.7 MPa by circulating hydrogen compressor 10 and returned to ortho-butene reactor 5 for recycling. The dehydrogenated liquid phase at the bottom of cooling separator 7 and cryogenic separator 9 is sent back to main tower 1, where unreacted feedstock and 2-butene product with a mass fraction greater than 85% are separated by distillation.

[0086] The above description is merely a few embodiments of this application and is not intended to limit this application in any way. Although this application discloses preferred embodiments as described above, it is not intended to limit this application. Any changes or modifications made by those skilled in the art without departing from the scope of the technical solution of this application using the disclosed technical content are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. A mixed olefin conversion device, characterized in that, The mixed olefin conversion unit is a circulating reaction unit, comprising a distillation unit, a reaction unit, and a cooling and separation unit connected in sequence; The distillation unit includes a distillation column, which includes a feed end and a separation end. The feed end includes inlet I, inlet II, and inlet III. The separation end includes a liquid phase separation outlet for light components and a liquid phase separation outlet for heavy components. The reaction unit includes a reactor, which includes a reactor inlet I, a reactor inlet II, and a reaction product outlet. The outlet of the light component liquid phase separator is connected to the reactor inlet I pipeline; The distillation unit also includes a pressure boosting device I; The pressurization device I is installed on the connecting pipeline between the outlet of the light component liquid phase separator and the inlet I of the reactor; The cooling separation unit is a two-stage gas-liquid phase separation unit, comprising a cooling device I, a first-stage gas-liquid phase separation device, a cooling device II, and a second-stage gas-liquid phase separation device connected in sequence. The first-stage gas-liquid phase separation device is provided with a first inlet, a gas phase outlet I, and a liquid phase outlet I; the second-stage gas-liquid phase separation device is provided with a second inlet, a gas phase outlet II, and a liquid phase outlet II. The reaction product outlet, cooling device I, and first inlet are connected in sequence by pipelines; the gas phase outlet I, cooling device II, and second inlet are connected in sequence by pipelines; the gas phase outlet II is connected to the reactor inlet II by pipeline; the liquid phase outlet I and liquid phase outlet II are connected to inlet I and inlet II by pipelines, respectively. The cooling device I is a water-cooling device; The cooling device II is a cryogenic device; The mixed olefin conversion unit is also equipped with a hydrogen supply end; the hydrogen supply end is connected to the reactor inlet II pipeline; The mixed olefins contain 1-butene, 2-butene, isobutene, ethylene, propylene, and methane.

2. The mixed olefin conversion apparatus according to claim 1, characterized in that, The separation end is provided with a light component gas phase outlet; The distillation column is equipped with a condenser at the top.

3. The mixed olefin conversion apparatus according to claim 1, characterized in that, The theoretical number of plates in the distillation column is 30 to 110. The reflux ratio of the distillation column is 5 to 60.

4. The mixed olefin conversion apparatus according to claim 1, characterized in that, The reaction unit also includes preheater I and preheater II; The distillation column, preheater I, and reactor inlet I are sequentially connected by pipelines. The preheater II is located on the inlet pipe of the reactor inlet II.

5. The mixed olefin conversion apparatus according to claim 1, characterized in that, The separation unit also includes a pressurization device II; The gas phase outlet II, the pressurization device II, and the reactor inlet II are connected in sequence via pipelines.

6. A method for converting mixed olefins, characterized in that, The method includes: a raw material containing mixed C4 olefins is introduced into a reaction device containing a catalyst through inlet III, and the reaction is carried out to obtain a product containing 2-butene; The reaction apparatus is selected from the mixed olefin conversion apparatus according to any one of claims 1 to 5.

7. The conversion method according to claim 6, characterized in that, Includes the following steps: (1) The raw material containing mixed C4 olefins is fed into the distillation column through raw material inlet III, and the light component gas phase, light component liquid phase and heavy component liquid phase are separated. The light component gas phase is discharged through the light component gas phase outlet, the heavy component liquid phase is discharged through the heavy component liquid phase separator outlet, and the light component liquid phase enters the reactor through the light component liquid phase separator outlet. (2) The light component liquid phase entering the reactor reacts with the hydrogen gas entering the reactor through reactor inlet II to obtain the reaction product; The reactor contains a catalyst; (3) The reaction products are separated into gas phase I and liquid phase I by the first-stage gas-liquid phase separation device; gas phase I enters the second-stage gas-liquid phase separation device through gas phase outlet I for secondary cooling and separation, and gas phase II and liquid phase II are separated. The gas phase II enters the reactor through the gas phase outlet II and the reactor inlet II; The liquid phase I enters the distillation column sequentially through liquid phase outlet I and inlet I; The liquid phase II enters the distillation column sequentially through liquid phase outlet II and inlet II; (4) The liquid phase I and liquid phase II are mixed with the raw material containing mixed C4 olefins in the distillation column to obtain a mixed raw material. The mixed raw material is then distilled in the distillation column to separate the heavy component liquid phase, the light component liquid phase and the light component gas phase.

8. The conversion method according to claim 7, characterized in that, The operating pressure of the distillation column is 0.1~3.0 MPa; The top temperature of the distillation column is -40~42℃. o C; The cooling temperature of the first-stage gas-liquid phase separation device is 42~65℃; The cooling temperature of the second-stage gas-liquid phase separation device is -60~-10℃; The catalytic reaction temperature is 250℃~600℃.

9. The conversion method according to claim 7, characterized in that, The light component liquid phase is preheated by preheater I before entering the reactor; The hydrogen gas is preheated by preheater II before entering the reactor; The light component liquid phase is pressurized by pressurizing device I before entering the reactor; The hydrogen gas is pressurized by pressurization device II before entering the reactor.

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