Method and apparatus for selective hydrogenation of butadiene extract tail gas

Abstract

The present invention relates to the petrochemical industry and discloses a method for selective hydrogenation of butadiene extraction tail gas and a selective hydrogenation device therefor. The method for selective hydrogenation of butadiene extraction tail gas includes the following steps: (1) supplying alkyne-containing tail gas from a butadiene extraction unit to a raw material tank, and optionally supplying impurities entrained in the alkyne-containing tail gas to the raw material tank; (2) pressurizing the C4 raw material in the raw material tank to a pressure required for the reaction by a supply pump, then combining with a circulating C4 stream from a first-stage reactor outlet buffer tank and supplying it to a first-stage mixer, where it is mixed with hydrogen gas and supplied to the first-stage reactor to carry out the first-stage hydrogenation reaction; and the first-stage reaction stream obtained by the reaction is supplied to the first-stage reactor outlet buffer tank; the hydrogen gas required for the reaction in the first-stage reactor is supplied through a first supply form or a second supply form: in the first supply form, all of the hydrogen gas required for the reaction is supplied through the first-stage reactor outlet buffer tank. (3) there is no gas phase discharge from the first-stage reactor outlet buffer tank, and the liquid phase product is split into at least two streams, the first stream being returned to the first-stage reactor as a recycled C4 stream, and the second stream being used as a feed to the stabilization tower or subjected to further hydrotreating before being fed to the stabilization tower; and (4) the C4 hydrogenation product is recovered after separation in the stabilization tower.

Description

[Technical Field]

[0001] The present invention relates to the field of the petrochemical industry, and more particularly to a selective hydrogenation method and apparatus for butadiene extract tail gas. [Background technology]

[0002] Currently, butadiene extraction units generally recover 1,3-butadiene from the decomposed C4 fraction of an ethylene unit through two-stage extraction distillation and conventional distillation, while simultaneously producing a by-product tail gas rich in alkynes and dienes. Depending on the different techniques used in the butadiene extraction unit, the by-product alkyne-containing tail gas can be in two different states, namely liquid and gas phases. However, a common characteristic is the relatively high concentration of vinylacetylene (VA) and ethylacetylene (EA) in the tail gas, with the VA content typically being 20%, and up to 40% by weight. Currently, to ensure safety, this alkyne and diene-rich tail gas needs to be diluted with C4 raffinate and then sold as liquefied gas or directly discharged into a flame for combustion. Recycling and utilizing the tail gas would yield economic and social benefits.

[0003] Currently, for C4 sources rich in alkynes and dienes, the industry primarily converts them into high-value products through hydrogenation, one method used being selective hydrogenation. The hydrogenation activity of unsaturated hydrocarbons increases with the degree of unsaturation, and alkynes in C4 components react with hydrogen gas preferentially to diolefins and monoolefins. However, diolefins and monoolefins in C4 components can also react vigorously with hydrogen gas at lower temperatures under catalytic activity to form alkanes. The selective hydrogenation reaction of C4 components is a three-phase reaction involving gas, liquid, and solid. However, because the amount of hydrogen gas required for the reaction is small, the dissolution of hydrogen gas into the C4 components is limited, and it then reacts with reactants such as alkynes and dienes in the C4 components by mass transfer across a liquid film to the surface of the catalyst. The inventors have found that on the surface of a catalyst where the hydrogenation reaction is restricted by hydrogen gas, i.e., where there is insufficient hydrogen gas, alkynes cannot undergo the hydrogenation reaction and therefore cannot be completely removed from the product, and polymerization reactions of these alkynes are likely to occur, generating heavy components and degrading the performance of the catalyst; and that when there is an excess of hydrogen gas, the diolefins and butenes produced by the hydrogenation reaction of alkynes undergo further hydrogenation reactions to form alkenes and alkanes, which can lead to a decrease in the selectivity of the hydrogenation reaction of alkynes.

[0004] CN102285859A discloses a method for the selective hydrogenation of a C4 stream, in which a C4 stream with a high butadiene content is selectively hydrogenated using a palladium-silver two-component catalyst or a palladium-silver multi-component catalyst with alumina as a support, thereby obtaining a product rich in 1-butene, with butadiene and alkyne content of less than 10 ppm, and usable as a feedstock for an MTBE plant. However, this patent does not include butadiene tail gas rich in vinylacetylene (VA) and ethylacetylene (EA), and the hydrogen gas is directly allocated to the reactor inlet, and its distribution is easily influenced by the equipment and pipeline layout, making it difficult to guarantee a uniform distribution of hydrogen and thus limiting the selectivity of the catalyst.

[0005] CN103121905A discloses a method for recovering butadiene extract tail gas, in which alkynes undergo selective hydrogenation using a nickel-palladium-copper-silver polymetallic catalyst to obtain a butadiene-rich product, which is then sent to a butadiene unit for further recovery of butadiene. In this method, hydrogen gas is supplied directly to the reactor inlet, and its distribution is easily affected by the arrangement of the equipment and pipelines, making it difficult to ensure a uniform distribution of hydrogen and limiting the selectivity of the catalyst. In addition, heavy components such as polymers produced by the selective hydrogenation reaction are not removed from the hydrogenation C4 stream used for diluting the feedstock, so they can easily accumulate in the system, leading to a decrease in catalyst performance and lifespan.

[0006] CN108863697A discloses a method for recovering butadiene by selective hydrogenation of alkynes, employing a palladium-molybdenum selective hydrogenation catalyst. This method achieves a vinylacetylene content of less than 1.0 wt% and a butadiene selectivity of more than 46% after hydrogenation of alkynes in a C4 stream, thus meeting the supply requirements of a butadiene extraction unit. However, this patent uses a precious metal-containing palladium catalyst, resulting in high costs, and does not include a process for a selective hydrogenation unit for butadiene tail gas.

[0007] CN103787811A discloses a method for utilizing butadiene tail gas, in which a Ni-based catalyst having a titanium oxide-alumina composite as a support is employed to hydrogenate all alkynes, dienes, and monoenes in the tail gas, resulting in a product having an olefin content of less than 5%, which can be used as a raw material for decomposition in an ethylene plant; however, this patent does not cover the field of selective hydrogenation.

[0008] CN109806885A discloses a Pdx / Cu monoatomic catalyst for selective hydrogenation of C4 streams and a method for preparing the same. After hydrogenation of unsaturated olefins in the C4 stream, the selectivity for total butene is greatly improved, but the reaction temperature is relatively high, resulting in greater energy consumption; furthermore, it does not disclose the process flow.

[0009] In recent years, much research has been conducted on C4 component-selective hydrogenation catalysts, resulting in significant improvements in catalyst activity and selectivity. However, as mentioned above, inaccurate control and heterogeneous distribution of hydrogen gas severely limit catalyst selectivity, making it difficult for selective hydrogenation reactions to simultaneously meet the requirements of high conversion rates for alkynes and dienes, and high yields for monoolefins. Compared to small-scale laboratory pilot plants, actual industrial plants have a 100-fold increase in production scale, making precise control of hydrogen gas more difficult and hydrogen gas distribution more heterogeneous. Depending on the characteristics of the industrial plant, it is increasingly necessary to improve the state of selective hydrogenation reactions from the perspective of processing and control.

[0010] Therefore, there is still a need for a method and apparatus for the selective hydrogenation of butadiene extract tail gas that can promote the uniform distribution of hydrogen gas during the selective hydrogenation reaction, improve the selectivity of the selective hydrogenation reaction, and extend the service life of the catalyst. [Overview of the project]

[0011] The object of the present invention is to provide a selective hydrogenation method and apparatus for butadiene extract tail gas, thereby solving the shortcomings of the prior art. By improving the method of allocating and metering the hydrogen gas required for the selective hydrogenation reaction, it is possible to solve the problems of uneven distribution of reactor temperature due to the non-uniform distribution of hydrogen, and the subsequent decrease in the selectivity of the hydrogenation reaction. While ensuring accurate metering of hydrogen, it promotes uniform distribution in the selective hydrogenation reaction, improves the selectivity of the selective hydrogenation reaction, reduces the occurrence of side reactions, and extends the service life of the catalyst.

[0012] To achieve the above objective, one aspect of the present invention is a selective hydrogenation method for butadiene extract tail gas, characterized by comprising the following: (1) Alkyne-containing tail gas from the butadiene extraction unit is supplied to the raw material tank, and any impurities associated with the alkyne-containing tail gas are optionally removed before being supplied to the raw material tank; (2) The C4 raw material in the raw material tank is pressurized by the supply pump to the pressure required for the reaction, then merged with the circulating C4 stream from the buffer tank at the outlet of the first stage reactor, supplied to the first stage mixer where it is mixed with hydrogen gas, supplied to the first stage reactor where it undergoes the first stage hydrogenation reaction, and the first stage reaction stream obtained from the reaction is supplied to the buffer tank at the outlet of the first stage reactor; The hydrogen gas required for the reaction in the first-stage reactor is supplied via either the first or second supply method: The first supply configuration includes the provision that all of the hydrogen gas required for the reaction is supplied through the buffer tank at the outlet of the first-stage reactor, and then supplied to the first-stage reactor through the first pathway at the outlet of the buffer tank at the outlet of the first-stage reactor; The second supply configuration includes the supply of a portion of the hydrogen gas required for the reaction through a buffer tank at the outlet of the first-stage reactor, and then supplied to the first-stage reactor through a first pathway at the outlet of the buffer tank at the outlet of the first-stage reactor; and the remaining portion of the hydrogen gas being supplied through a first-stage mixer and then supplied to the first-stage reactor; (3) There is no gas phase discharge from the buffer tank at the outlet of the first stage reactor, and the liquid phase product is divided into at least two streams, the first stream being returned to the first stage reactor as a circulating C4 stream, and the second stream being used as feed to the stabilization tower or subjected to further hydrogenation before being fed to the stabilization tower; (4) The C4 hydrogenation product is recovered after separation in the stabilization tower.

[0013] Another aspect of the present invention is an apparatus for selective hydrogenation of butadiene extract tail gas, used to carry out the method for selective hydrogenation of butadiene extract tail gas of the present invention, the apparatus comprising a raw material tank, a feed pump, a coalescer, a first-stage mixer, a first-stage reactor, a first-stage reactor outlet buffer tank, a circulating C4 cooler, a stabilization tower, and a hydrogen gas supply pipeline; The raw material tank, supply pump, coalescer, first-stage mixer, first-stage reactor, and first-stage reactor outlet buffer tank are connected in order; The outlet pipeline of the buffer tank outlet of the first-stage reactor is divided into at least two paths: the first path is connected in sequence to the circulating C4 cooler, the first-stage mixer, and the first-stage reactor; and the second path is connected directly or indirectly to the stabilization tower; The hydrogen gas supply pipeline is divided into at least a first pipeline and optionally a second pipeline, the first pipeline being connected to the first-stage reactor outlet buffer tank and the second pipeline being connected to the first-stage mixer; Preferably, the first-stage reactor is a fixed-bed reactor; Preferably, the first path is connected to a circulating C4 cooler via a circulation pump.

[0014] The technical solution of the present invention has at least the following beneficial effects: By employing the method and apparatus of the present invention, butadiene extraction tail gas (alkyne-containing tail gas derived from a butadiene extraction unit) can be recycled completely and safely; by optimizing the hydrogen gas allocation and supply methods of the selective hydrogenation process and using a method of dissolving hydrogen gas and allocating and adding it, the distribution of hydrogen gas in the selective hydrogenation reaction is effectively improved, the non-uniform reactor temperature distribution caused by the non-uniform distribution of hydrogen gas is overcome, and the selectivity of alkenes in the selective hydrogenation reaction of butadiene tail gas is improved; In addition, by optimizing the raw material dilution method and diluting the raw materials with C4 hydrogenation products that have low impurity content of 1,3-butadiene, butene-1, and heavy components, the problem of high alkyne concentration in the raw material tank can be solved, the problem of high concentration of gas phase alkyne tail gas during raw material pressurization, liquefaction, and recovery can be solved, and the possibility of rehydrogenation of 1,3-butadiene and butene-1 caused by backmixing of the diluent C4 stream can be reduced, thereby effectively reducing product loss, improving product yield, reducing the impact of heavy component impurities on the catalyst, and extending the service life of the catalyst. In addition, the present invention provides a water washing tower that can further remove water-soluble impurities from the butadiene extract tail gas raw material, thereby improving the adaptability of the raw material.

[0015] Other features and advantages of the present invention will be described in detail in the following description.

[0016] Preferred embodiments of the present invention will be described in detail below with reference to the attached drawings. [Brief explanation of the drawing]

[0017] [Figure 1]A schematic diagram of a method for selective hydrogenation of butadiene extract tail gas according to an embodiment of the present invention is shown: Device signage is as follows: 11, raw material tank; 12, feed pump; 13, coalescer; 14, first-stage mixer; 15, first-stage reactor; 16, first-stage reactor outlet buffer tank; 17, circulation pump; 18, circulation C4 condenser; 19, diluent C4 condenser; 110, stabilization column; 111, top condenser; 112, reflux tank; 113, reflux pump; 114, tail gas condenser; 115, diluent C4 pump; 116, hydrogen gas supply pipeline; Stream signage is as follows: 1101, alkyne-containing tail gas (butadiene tail gas) derived from the butadiene extraction unit; 1102, diluent C4 stream; 1107, first-stage reactor feedstock; 1108, first-stage reactor product; 1109, circulating C4 stream; 1112, stabilization column feedstock; 1115, stabilization column reflux; 1116, non-condensable gas; 1117, heavy components; 1118, C4 hydrogenation product; 1201, reaction pressure compensating hydrogen gas; 1202, reaction auxiliary hydrogen gas. [Figure 2]A schematic diagram of a method for selective hydrogenation of butadiene extract tail gas according to an embodiment of the present invention is shown: The reference numerals of the apparatus are as follows: 21, raw material tank; 22, feed pump; 23, coalescer; 24, first-stage mixer; 25, first-stage reactor; 26, first-stage reactor outlet buffer tank; 27, circulation pump; 28, circulation C4 condenser; 29, diluent C4 condenser; 210, second-stage feed condenser; 211, second-stage mixer; 212, second-stage reactor; 213, second-stage reactor outlet buffer tank; 214, stabilization column; 215, top condenser; 216, reflux tank; 217, reflux pump; 218, hydrogen gas supply pipeline; The reference numerals of the streams are as follows: 2101, alkyne-containing tail gas (butadiene tail gas) derived from the butadiene extraction unit; 2102, diluent C4 stream; 2107, first-stage reactor feedstock; 2108, first-stage reactor product; 2109, circulating C4 stream; 2115, second-stage reactor feedstock; 2116, second-stage reactor product; 2120, stabilizing column reflux; 2121, non-condensable gas; 2122, C4 alkene product; 2123, heavy components; 2201, reaction pressure compensation hydrogen gas; 2202, first-stage reaction mixed hydrogen gas; 2203, second-stage reaction mixed hydrogen gas. [Figure 3]Schematic diagram of a method for the selective hydrogenation of butadiene extraction tail gas according to an embodiment of the present invention: The symbols of the devices are described as follows: 31, blower suction tank; 32, blower; 33, liquefied condenser; 34, C4 collection tank; 35, booster pump; 36, water wash tower; 37, raw material tank; 38, supply pump; 39, coarser; 310, first-stage mixer; 311, first-stage reactor; 312, first-stage reactor outlet buffer tank; 313, circulation pump; 314, circulation cooler; 315, stabilization tower; 316, top condenser; 317, reflux tank; 318, reflux pump; 319, tail gas condenser; 320, hydrogen gas supply pipeline; The symbols of the streams are described as follows: 3101, alkyne-containing tail gas (butadiene tail gas) from the butadiene extraction unit; 3103, liquefied C4 raw material; 3105, C4 supply; 3107, first-stage reactor raw material; 3108, first-stage reactor product; 3109, circulating C4 stream; 3112, stabilization tower feed; 3115, stabilization tower reflux; 3116, non-condensable gas; 3117, heavy components; 3118, C4 hydrogenation product; 3119, diluent C4 stream; 3201, reaction pressure compensation hydrogen gas; 3202, reaction mixed hydrogen gas.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, the present invention will be specifically described with reference to specific examples. It should be noted that the following examples are only used to further illustrate the present invention and should not be construed as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art in accordance with the present invention still fall within the protection scope of the present invention.

[0019] Also, various specific technical features described in the following specific embodiments can be appropriately combined as long as they do not conflict. To avoid unnecessary repetition, various possible combinations are not further described in the present invention.

[0020] One aspect of the present invention provides a method for selectively hydrogenating butadiene extract tail gas, characterized by comprising the following: (1) Alkyne-containing tail gas from the butadiene extraction unit is supplied to the raw material tank, and any impurities associated with the alkyne-containing tail gas are optionally removed before being supplied to the raw material tank; (2) The C4 raw material in the raw material tank is pressurized by the supply pump to the pressure required for the reaction, then merged with the circulating C4 stream from the buffer tank at the outlet of the first stage reactor, supplied to the first stage mixer where it is mixed with hydrogen gas, supplied to the first stage reactor where it undergoes the first stage hydrogenation reaction, and the first stage reaction stream obtained from the reaction is supplied to the buffer tank at the outlet of the first stage reactor; The hydrogen gas required for the reaction in the first-stage reactor is supplied via either the first or second supply method: The first supply configuration includes the provision that all of the hydrogen gas required for the reaction is supplied through the buffer tank at the outlet of the first-stage reactor, and then supplied to the first-stage reactor through the first pathway at the outlet of the buffer tank at the outlet of the first-stage reactor; The second supply configuration includes the supply of a portion of the hydrogen gas required for the reaction through a buffer tank at the outlet of the first-stage reactor, and then supplied to the first-stage reactor through a first pathway at the outlet of the buffer tank at the outlet of the first-stage reactor; and the remaining portion of the hydrogen gas being supplied through a first-stage mixer and then supplied to the first-stage reactor; (3) There is no gas phase discharge from the buffer tank at the outlet of the first stage reactor, and the liquid phase product is divided into at least two streams, the first stream being returned to the first stage reactor as a circulating C4 stream, and the second stream being used as feed to the stabilization tower or subjected to further hydrogenation before being fed to the stabilization tower; (4) The C4 hydrogenation product is recovered after separation in the stabilization tower.

[0021] In this invention, "alkyne-containing tail gas derived from a butadiene extraction unit" refers to the alkyne and diene-rich tail gas produced by a butadiene extraction unit when recovering 1,3-butadiene from the decomposition C4 fraction of an ethylene unit. The alkyne-containing tail gas derived from a butadiene extraction unit can be used interchangeably with the butadiene extraction tail gas. The concentrations of vinylacetylene (VA) and ethylacetylene (EA) in the tail gas are relatively high, with VA content typically 20%, and up to 40% by weight. Depending on the different techniques employed by the butadiene extraction unit, the resulting alkyne-containing tail gas may exist in two states: liquid and gas. <Process (1)> In one embodiment, alkyne-containing tail gas derived from a butadiene extraction unit can be supplied directly to a raw material tank.

[0022] Alkynes such as vinylacetylene in alkyne-containing tail gases have autodecomposition and explosive properties, which pose a safety hazard. Therefore, it is generally necessary to dilute the tail gas to reduce its concentration and prevent explosions. According to the present invention, materials containing low amounts of 1,3-butadiene, butene-1, and heavy components that tend to affect the activity and service life of catalysts can be used as diluents.

[0023] In one embodiment, the alkyne-containing tail gas can be diluted with a side-draw diluent C4 stream derived from a stabilized column. Preferably, the mass flow rate ratio of the diluent C4 stream to the alkyne-containing tail gas is 1 to 30:1, for example 1 to 20:1, for example 1 to 10:1. In the present invention, the side-draw diluent C4 stream derived from the stabilized column mainly contains low amounts of 1,3-butadiene, butene-1, and heavy components that tend to affect the activity and service life of the catalyst.

[0024] In one embodiment, the alkyne-containing tail gas may also be diluted with a diluent C4 stream originating from a buffer tank at the outlet of the first-stage reactor. Preferably, the mass flow rate ratio of the diluent C4 stream to the alkyne-containing tail gas is 1 to 5:1, for example, 1 to 4:1.

[0025] The choice between a diluent C4 stream derived from a stabilization tower or a diluent C4 stream derived from a buffer tank at the outlet of the first-stage reactor primarily depends on the content of heavy components in the catalyst and diluent C4 stream used in the selective hydrogenation reaction.

[0026] In this invention, the alkyne-containing tail gas may contain impurities such as acetonitrile (ACN), N-methylpyrrolidone (NMP), and N,N-dimethylformamide (DMF). To reduce the impact of these impurities on subsequent processes, the alkyne-containing tail gas may be treated to remove any impurities before being supplied to the raw material tank. For example, the installation of a water scrubbing tower can remove water-soluble impurities from the alkyne-containing tail gas, thereby improving the adaptability of the raw material.

[0027] In one embodiment, alkyne-containing tail gas can be supplied to a water scrubbing tower to remove impurities associated with the alkyne-containing tail gas, and then supplied to a raw material tank.

[0028] In one embodiment, if the alkyne-containing tail gas is a gas-phase alkyne-containing tail gas, the gas-phase alkyne-containing tail gas can be pressurized, liquefied into a liquid-phase alkyne-containing tail gas, and then supplied to a water scrub tower. For example, the alkyne-containing tail gas can be supplied to a blower suction tank, pressurized by a blower, condensed and liquefied by a liquefaction condenser, then supplied to a C4 collection tank, subsequently pressurized by a booster pump, and supplied to a water scrub tower where impurities entrained in the alkyne-containing tail gas are removed.

[0029] According to the present invention, when the gas phase alkyne-containing tail gas undergoes impurity removal treatment, the alkyne-containing tail gas in the blower suction tank can be diluted.

[0030] In one embodiment, the gas phase alkyne-containing tail gas in the blower suction tank can be diluted with side-draw gas phase C4 hydrogenation products from the stabilization tower. Preferably, the mass flow rate ratio of the gas phase C4 hydrogenation products to the gas phase alkyne-containing tail gas is 1 to 30:1, for example 1 to 20:1, or for example 1 to 10:1.

[0031] In one embodiment, the gas phase alkyne-containing tail gas in the blower suction tank may also be diluted with a diluent C4 stream originating from the first-stage reactor outlet buffer tank. Preferably, the mass flow rate ratio of the diluent C4 stream to the alkyne-containing tail gas is 1 to 5:1, for example, 1 to 4:1.

[0032] The choice between a diluent C4 stream derived from a stabilization tower or a diluent C4 stream derived from a buffer tank at the outlet of the first-stage reactor primarily depends on the content of heavy components in the catalyst used in the selective hydrogenation reaction and the diluent C4 stream.

[0033] According to the present invention, the raw material tank has an operating pressure of 0.5 to 1.0 MPaG.

[0034] According to the present invention, preferably, the blower suction tank has an operating pressure of 0 to 20 kPa.

[0035] According to the present invention, the condensed liquefied gas in the liquefied condenser has a temperature of 0 to 20°C.

[0036] According to the present invention, the liquefaction condenser has a pressure of 50 to 100 kPa.

[0037] According to the present invention, the operating pressure of the water scrubbing tower is 0.5 to 1.0 MPaG.

[0038] According to the present invention, the mass ratio of washing water to C4 raw material in the washing tower is 1 to 5:1. <Process (2)> After the C4 raw material in the raw material tank is pressurized to the pressure required for the reaction by the supply pump, it is joined with the circulating C4 stream from the buffer tank at the outlet of the first stage reactor and enters the first stage mixer. After being mixed with hydrogen gas in the first stage mixer, it enters the first stage reactor to carry out the first stage hydrogenation reaction, and the first stage reaction stream obtained from the reaction enters the buffer tank at the outlet of the first stage reactor. Preferably, the C4 raw material in the raw material tank is diluted C4 raw material.

[0039] According to the present invention, the hydrogen gas necessary for the first-stage reactor reaction is allocated and supplied through a first supply method or a second supply method.

[0040] In the first supply configuration, all of the hydrogen gas required for the reaction is supplied to the first-stage reactor through the buffer tank at the outlet of the first-stage reactor. In the second supply configuration, a portion of the hydrogen gas required for the reaction is supplied to the first-stage reactor through the buffer tank at the outlet of the first-stage reactor, and the remaining portion of the hydrogen gas required for the reaction is supplied to the first-stage reactor through the first-stage mixer.

[0041] According to the present invention, in the first supply configuration, the hydrogen gas required by the first-stage hydrogenation reactor controls the pressure of the reaction system through pressure compensation, and all of the hydrogen gas enters the liquid phase C4 stream through a dissolution method and is then supplied from the first-stage reactor to the first-stage hydrogenation reactor along with the circulating C4 stream. In the second supply configuration, a portion of the hydrogen gas required for the reaction is supplied through the buffer tank at the outlet of the first-stage reactor. This portion of the hydrogen gas controls the pressure of the reaction system through pressure compensation and simultaneously enters the liquid phase C4 stream through a dissolution method and is then supplied from the first-stage reactor to the first-stage hydrogenation reactor along with the circulating C4 stream.

[0042] In the present invention, by employing a method of dissolving hydrogen gas and partially or completely replacing the prior art method of directly introducing hydrogen gas into the reactor inlet, a uniform distribution of hydrogen gas during the hydrogenation reaction is ensured, thereby improving the selectivity of the hydrogenation reaction.

[0043] In the second supply configuration, the mass ratio of hydrogen gas required for the reaction to the hydrogen gas required for the first stage hydrogenation reaction is 0.3 or higher, preferably 0.5 or higher, and the hydrogen gas required for the first stage hydrogenation reaction is the sum of a portion of the hydrogen gas required for the reaction and the remaining portion of the hydrogen gas.

[0044] In the second supply configuration, the sum of the amount of hydrogen gas required for the reaction and the amount of the other part of the hydrogen gas is equal to the total amount of hydrogen gas required for the hydrogenation reaction.

[0045] According to the present invention, the C4 raw material in the raw material tank is pressurized to 1.0 to 4.0 MPaG by a supply pump, and the mass flow rate ratio of the circulating C4 stream to the C4 raw material is 5 to 30:1. The inlet temperature of the first-stage reactor is 5 to 60°C, for example, 20 to 60°C; and the liquid space velocity is 1 to 50 h -1 The pressure in the first-stage reactor is controlled by pressure-compensating hydrogen gas in the buffer tank at the outlet of the first-stage reactor; the reaction pressure is 1.0 to 4.0 MPaG.

[0046] Preferably, the first-stage reactor is a fixed-bed reactor. The reactor is packed with a selective hydrogenation catalyst.

[0047] According to the present invention, a selective hydrogenation catalyst in the prior art, preferably a selective hydrogenation catalyst disclosed in CN102240547, can be used in a selective hydrogenation reaction. Based on the total weight of the catalyst, the palladium-containing catalyst preferably comprises the following components: 0.015 to 2.00 wt% palladium, 0.005 to 3.0 wt% an accelerator metal, and the remainder as a support, where the accelerator metal is at least one selected from lead, silver, tin, magnesium, and calcium, and the support is at least one selected from aluminum oxide, titanium oxide, and magnesium oxide.

[0048] According to the present invention, the selective hydrogenation reaction may also use selective hydrogenation catalysts disclosed in the prior art, such as CN102886262, CN10886397 and / or CN104707622, ​​preferably the selective hydrogenation catalyst disclosed in CN104707622. Based on the total weight of the catalyst, the palladium-free catalyst preferably comprises the following components: 5-15 wt% copper, 0.1-3 wt% iridium, 0.1-3 wt% phosphorus, 0.5-3.0 wt% accelerator metal, and the remainder as a support, where the accelerator metal is at least one selected from nickel, zirconium, lead and tin, and the support is at least one selected from alumina, titania, silica, titania-alumina composite oxide, titania-silica composite oxide and alumina-silica composite oxide.

[0049] Both palladium-containing and palladium-free catalysts can be used in the production of 1,3-butadiene. Compared to palladium-free catalysts, palladium-containing catalysts have higher selectivity and higher olefin yields. However, because palladium-containing catalysts contain precious metal elements, the investment and operating costs of equipment using palladium-containing catalysts are higher than those of equipment using palladium-free catalysts. Using catalysts that do not contain precious metals can effectively reduce the investment and operating costs of the equipment. Therefore, when selecting a catalyst, it is necessary to weigh the relationship between cost and olefin yield. For the production of butene-1, palladium-containing catalysts are chosen due to their much higher selectivity and olefin yield. <Process (3)> There are no gaseous emissions from the buffer tank at the outlet of the first-stage reactor, and the liquid-phase product is split into at least two streams: the first stream is returned to the first-stage reactor as a circulating C4 stream, and the second stream is either fed directly to the stabilization tower as feed or undergoes further hydrogenation before being fed to the stabilization tower.

[0050] In this invention, it is considered whether the second stream of the buffer tank at the outlet of the first-stage reactor needs to be further hydrogenated depending on the demands of the product. For example, if a higher content of 1,3-butadiene is required in the product, the second stream can be used as feed and supplied directly to the stabilization column without further hydrogenation. If a high content of butene-1 and a low content of 1,3-butadiene are required in the product, the second stream needs to be further hydrogenated before being supplied to the stabilization column.

[0051] Further hydrogenation of the second stream before it is supplied to the stabilization tower includes using the second stream as feed to the second stage reactor, supplying it to the second stage reactor through a second stage feed cooler and a second stage mixer to carry out the second stage hydrogenation reaction, and then the second stage reaction stream obtained from the reaction in the second stage reactor passing through the second stage reactor outlet buffer tank and entering the stabilization tower.

[0052] Similar to the first-stage reactor, the hydrogen gas required for the second-stage reactor reaction is allocated and supplied through a third or fourth supply configuration. In the third supply configuration, all of the hydrogen gas required for the reaction is supplied through the first-stage reactor outlet buffer tank, and then supplied to the second-stage reactor through a second route at the outlet of the first-stage reactor outlet buffer tank. In the fourth supply configuration, a portion of the hydrogen gas required for the reaction is supplied to the first-stage reactor outlet buffer tank, and then supplied to the second-stage reactor through a second route at the outlet of the first-stage reactor outlet buffer tank; the remaining portion of the hydrogen gas is supplied through the second-stage mixer, and then supplied to the second-stage reactor.

[0053] In the third supply configuration, the hydrogen gas required by the second-stage reactor controls the pressure of the first-stage reaction system through pressure compensation, and all of the hydrogen gas enters the liquid phase C4 stream through a dissolution method and is supplied to the second-stage reactor along with the feed for the second-stage reactor. In the fourth supply configuration, a portion of the hydrogen gas required for the reaction is supplied through the buffer tank at the outlet of the first-stage reactor. This portion of the hydrogen gas controls the pressure of the first-stage reaction system through pressure compensation and simultaneously enters the liquid phase C4 stream through a dissolution method and is supplied to the second-stage reactor along with the feed for the second-stage reactor.

[0054] In the fourth supply configuration, the mass ratio of the portion of the hydrogen gas required for the reaction to the hydrogen gas required for the second stage hydrogenation reaction is 0.3 or higher, preferably 0.5 or higher, and the hydrogen gas required for the second stage hydrogenation reaction is the sum of the portion of the hydrogen gas required for the reaction and the remaining portion of hydrogen.

[0055] In the fourth supply configuration, the sum of the amount of hydrogen gas required for the reaction and the amount of hydrogen gas required for the other part of the reaction is equal to the total amount of hydrogen gas required for the second stage of the reaction.

[0056] In one embodiment, a two-step hydrogenation process may be used for alkyne-containing tail gas to produce butene-1, where alkynes and dienes in the alkyne-containing tail gas are selectively hydrogenated to produce monoolefins by dissolving hydrogen gas, and then light and heavy components are removed by a stabilization column to obtain a high-quality C4 product.

[0057] The first-stage reactor and the second-stage reactor each have an inlet temperature of 20-60°C, and the first-stage reactor operates for 10-50 hours. -1 The liquid space velocity is such that the second stage reactor lasts 1 to 10 hours. -1 The reactor has a liquid space velocity, and the first-stage reactor and the second-stage reactor each have an independent pressure of 1.0 to 4.0 MPaG, which is controlled by pressure-compensating hydrogen gas in the respective reactor outlet buffer tanks.

[0058] Both the first-stage and second-stage reactors are fixed-bed reactors, and the reactors are filled with a selective hydrogenation catalyst. As mentioned above, the palladium-containing catalyst is chosen for the production of butene-1 due to its much higher selectivity and olefin yield.

[0059] The first-stage selective hydrogenation reaction and the second-stage selective hydrogenation reaction may use a selective hydrogenation catalyst from the prior art, preferably a selective hydrogenation catalyst disclosed in CN102240547. Based on the total weight of the catalyst, the palladium-containing catalyst preferably comprises 0.015 to 2.00 wt% palladium, 0.005 to 3.0 wt% an accelerator metal, and the remainder as a support, where the accelerator metal is at least one selected from lead, silver, tin, magnesium, and calcium, and the support is at least one selected from aluminum oxide, titanium oxide, and magnesium oxide. <Process (4)> The C4 hydrogenation product is recovered after separation in a stabilization column and contains 1,3-butadiene and butene-1.

[0060] According to the present invention, when employing a one-stage hydrogenation process for producing 1,3-butadiene, a condenser, preferably a two-stage condenser, is used at the upper end of the stabilization column to recover the C4 component encompassed in the non-condensable gas. Liquid phase recovery of the hydrogenation product, which has a high content of 1,3-butadiene and butene-1, is carried out by a reflux tank at the upper end of the column, and heavy components are removed from the column kettle. A C4 hydrogenation product with low content of 1,3-butadiene, butene-1, and heavy components, which tend to adversely affect catalytic activity and lifetime, is obtained as a side draw. The side draw product can be used to dilute the C4 tail gas feedstock. The phase state of the side draw product in the stabilization column is either gas or liquid.

[0061] According to the present invention, when a two-stage hydrogenation process is employed to produce butene-1, the C4 product at the outlet of the second-stage reactor (the second-stage reaction stream obtained by the reaction in the second-stage reactor) enters the buffer tank at the outlet of the second-stage reactor, and the C4 stream originating from the bottom of the buffer tank enters the stabilization column. Non-condensable gases are removed from the top of the stabilization column, no liquid phase is obtained at the top of the column, total reflux is employed, heavy components are removed from the bottom of the column, and high-quality C4 olefin products are obtained as a side draw.

[0062] The stabilization tower has an operating pressure of 0.4 to 1.2 MPaG, a theoretical stage number of 10 to 40, and theoretical stage positions for recovering 5 to 35 side draws.

[0063] In the present invention, after liquid-phase butadiene tail gas is diluted and pressurized, a catalyst such as a noble metal-free catalyst is used for a selective hydrogenation reaction, and light and heavy components are removed through a stabilization column to obtain a C4 olefin product having low content alkynes and enriched 1,3-butadiene, which can be returned to a butadiene extraction unit for further recovery of 1,3-butadiene and monoolefins.

[0064] In a specific embodiment, the present invention provides a method for selectively hydrogenating butadiene extract tail gas, characterized by comprising the following: (1) Alkyne-containing tail gas from the butadiene extraction unit is supplied to the raw material tank; (2) The raw materials in the raw material tank are pressurized by the supply pump to the pressure required for the reaction, then merged with the circulating C4 stream from the buffer tank at the outlet of the first stage reactor, supplied to the first stage mixer where it is mixed with hydrogen gas, supplied to the first stage reactor where it undergoes the first stage hydrogenation reaction, and the first stage reaction stream obtained from the reaction is supplied to the buffer tank at the outlet of the first stage; The hydrogen gas required for the first-stage reactor is supplied via either the first or second supply method: The first supply configuration includes the provision that all of the hydrogen gas required for the reaction is supplied through the buffer tank at the outlet of the first-stage reactor, and then supplied to the first-stage reactor through the first pathway at the outlet of the buffer tank at the outlet of the first-stage reactor; The second supply configuration includes supplying a portion of the hydrogen gas required for the reaction through a buffer tank at the outlet of the first-stage reactor, and then supplying it to the first-stage reactor through a first pathway at the outlet of the buffer tank; and supplying the remaining portion of the hydrogen gas through a first-stage mixer, and then supplying it to the first-stage reactor; (3) There are no gas phase emissions from the buffer tank at the outlet of the first stage reactor, and the liquid phase product is split into two streams, the first stream being returned to the first stage reactor as a circulating C4 stream, and the second stream being used as feed to the stabilization tower; (4) The first-stage reaction stream obtained from the reaction in the first-stage reactor is supplied to the stabilization tower through the first-stage reactor outlet buffer tank, and separated through the stabilization tower to recover the C4 hydrogenation product.

[0065] In a preferred embodiment, in step (1), the alkyne-containing tail gas is diluted with a side-draw diluent C4 stream derived from the stabilization tower, preferably with a mass flow rate ratio of 1 to 30:1 between the diluent C4 stream and the alkyne-containing tail gas.

[0066] In a preferred embodiment, in step (2), in the second supply form, the mass ratio of the portion of the hydrogen gas required for the reaction to the hydrogen gas required for the hydrogenation reaction is 0.3 or more, preferably 0.5 or more, and the hydrogen gas required for the hydrogenation reaction is the sum of the portion of the hydrogen gas required for the reaction and the other portion of the hydrogen gas.

[0067] In a preferred embodiment, in step (1), the raw material tank has an operating pressure of 0.5 to 1.0 MPaG; In step (2), the diluted C4 raw material is pressurized to 1.0-4.0 MPaG by a supply pump, the mass flow rate ratio between the circulating C4 stream and the diluted C4 raw material is 5-30:1, the first-stage reactor has an inlet temperature of 5-60°C and a liquid space velocity of 1-40 h-1, the pressure in the first-stage reactor is controlled by pressure-compensating hydrogen gas in the first-stage reactor outlet buffer tank, and the reaction pressure is 1.0-4.0 MPaG; In step (4), the stabilization tower has an operating pressure of 0.4 to 1.0 MPaG, a theoretical stage number of 10 to 40, and theoretical stage positions of 5 to 35 for recovering side draws.

[0068] In a specific embodiment, the present invention provides a method for selectively hydrogenating butadiene extract tail gas, characterized by comprising the following: (1) Alkyne-containing tail gas from the butadiene extraction unit is supplied to the raw material tank, and the alkyne-containing tail gas in the raw material tank is diluted with diluent C4 stream from the buffer tank at the outlet of the first stage reactor; (2) The diluted raw materials in the raw material tank are pressurized by the supply pump to the pressure required for the reaction, then mixed with the circulating C4 stream from the buffer tank at the outlet of the first stage reactor and supplied to the first stage mixer, where they are mixed with hydrogen gas and then supplied to the first stage reactor for the first stage hydrogenation reaction, and the first stage reaction stream obtained from the reaction is supplied to the buffer tank at the outlet of the first stage reactor; The hydrogen gas required for the first-stage reactor reaction is supplied through either the first or second supply method: The first supply configuration includes supplying all the hydrogen gas necessary for the reaction through the first-stage reactor outlet buffer tank, and then entering the first-stage reactor through the first pathway at the outlet of the first-stage reactor outlet buffer tank; The second supply configuration includes supplying a portion of the hydrogen gas required for the reaction through a buffer tank at the outlet of the first-stage reactor, and then entering the first-stage reactor through a first pathway at the outlet of the buffer tank; and supplying the remaining portion of the hydrogen gas through a first-stage mixer, and then entering the first-stage reactor; (3) There is no gas phase discharge from the buffer tank at the outlet of the first stage reactor, and the liquid phase product is divided into three streams: the first stream is returned to the first stage reactor as the circulating C4 stream; the second stream is used as the feed for the second stage reactor and is supplied to the second stage reactor through the second stage feed cooler and second stage mixer to carry out the second stage hydrogenation reaction; the third stream is used as the diluent C4 stream and is supplied to the raw material tank; The hydrogen gas required for the reaction in the second-stage reactor is supplied through the third or fourth supply method: The third supply configuration includes supplying all the hydrogen gas necessary for the reaction through the buffer tank at the outlet of the first-stage reactor, and then entering the second-stage reactor through the second pathway at the outlet of the buffer tank at the outlet of the first-stage reactor; The fourth supply configuration includes the supply of a portion of the hydrogen gas required for the reaction through a buffer tank at the outlet of the first-stage reactor, and then entering the second-stage reactor through a second pathway at the outlet of the buffer tank; and the supply of the remaining portion of the hydrogen gas through a second-stage mixer, and then entering the second-stage reactor; (4) The second-stage reaction stream obtained from the reaction in the second-stage reactor is supplied to the stabilization column through the second-stage reactor outlet buffer tank, and separated through the stabilization column to recover the C4 olefin product as a side draw.

[0069] In a preferred embodiment, in step (2), in the second supply form, the mass ratio of the portion of the hydrogen gas required for the reaction to the hydrogen gas required for the first-stage hydrogenation reaction is 0.3 or more, preferably 0.5 or more, and the hydrogen gas required for the hydrogenation reaction is the sum of the portion of the hydrogen gas required for the reaction and the other portion of the hydrogen gas.

[0070] In a preferred embodiment, in step (3), in the fourth supply form, the mass ratio of the portion of the hydrogen gas required for the reaction to the hydrogen gas required for the second stage hydrogenation reaction is 0.3 or more, preferably 0.5 or more, and the hydrogen gas required for the second stage hydrogenation reaction is the sum of the portion of the hydrogen gas required for the reaction and the other portion of the hydrogen gas.

[0071] In a preferred embodiment, in step (1), the raw material tank has an operating pressure of 0.5 to 1.0 MPaG, and the mass flow rate ratio of the diluent C4 stream to the alkyne-containing tail gas is 1 to 5:1; In step (2), the dilution raw material is pressurized to 1.0-4.0 MPaG by the supply pump, and the mass flow rate ratio between the circulating C4 stream and the diluted C4 raw material is 5-30:1; In process (4), the stabilization tower has an operating pressure of 0.6 to 1.2 MPaG, a theoretical stage number of 10 to 40, and theoretical stage positions of 5 to 35 for recovering side draws; Here, the first-stage reactor and the second-stage reactor each have an inlet temperature of 20-60°C, and the first-stage reactor operates for 10-50 hours. -1 The liquid space velocity is such that the second stage reactor lasts 1 to 10 hours. -1 The reactor has a liquid space velocity, and the first-stage reactor and the second-stage reactor each have an independent pressure of 1.0 to 4.0 MPaG, which is controlled by pressure-compensating hydrogen gas in the respective reactor outlet buffer tanks.

[0072] In a specific embodiment, the present invention provides a method for selectively hydrogenating butadiene extract tail gas, characterized by comprising the following: (1) The gas phase alkyne-containing tail gas derived from the butadiene unit is supplied to a blower suction tank, the gas phase alkyne-containing tail gas is pressurized by the blower, condensed and liquefied in a liquefaction condenser, then supplied to a C4 collection tank, then pressurized by a booster pump, supplied to a washing tower where impurities accompanying the alkyne-containing tail gas are removed, and then supplied to a raw material tank; (2) The C4 raw material in the raw material tank is pressurized by the supply pump to the pressure required for the reaction, then merged with the circulating C4 stream from the buffer tank at the outlet of the first stage reactor and supplied to the first stage mixer, where it is mixed with hydrogen gas and supplied to the first stage reactor to undergo the hydrogenation reaction, and the first stage reaction stream obtained from the reaction is supplied to the buffer tank at the outlet of the first stage reactor; The hydrogen gas required for the reaction in the first-stage reactor is supplied through either the first or second supply method: The first supply configuration includes supplying all the hydrogen gas necessary for the reaction through the first-stage reactor outlet buffer tank, and then entering the first-stage reactor through the first pathway at the outlet of the first-stage reactor outlet buffer tank; The second supply configuration includes supplying a portion of the hydrogen gas required for the reaction through a buffer tank at the outlet of the first-stage reactor, and then entering the first-stage reactor through a first pathway at the outlet of the buffer tank; and supplying the remaining portion of the hydrogen gas through a first-stage mixer, and then entering the first-stage reactor; (3) There is no gas phase discharge from the buffer tank at the outlet of the first stage reactor, and the liquid phase product is divided into two streams, the first stream being returned to the first stage reactor as a circulating C4 stream, and the second stream being used as feed to the stabilization tower; (4) The first-stage reaction stream obtained from the reaction in the first-stage reactor is supplied to the stabilization tower through the first-stage reactor outlet buffer tank, and separated through the stabilization tower to recover the C4 hydrogenation product.

[0073] In a preferred embodiment, in step (1), the gas phase alkyne-containing tail gas in the blower suction tank is diluted with side-draw gas phase C4 hydrogenation products from the stabilization tower; preferably, the mass flow rate ratio of the gas phase C4 hydrogenation products to the gas phase alkyne-containing tail gas is 1 to 30:1.

[0074] In a preferred embodiment, in step (2), in the second supply form, the mass ratio of the portion of the hydrogen gas required for the reaction to the hydrogen gas required for the hydrogenation reaction is 0.3 or more, preferably 0.5 or more, and the hydrogen gas required for the hydrogenation reaction is the sum of the portion of the hydrogen gas required for the reaction and the other portion of the hydrogen gas.

[0075] In a preferred embodiment, in step (1), the blower suction tank has an operating pressure of 0 to 20 kPa; the condensed liquefied gas in the liquefied condenser has a temperature of 0 to 20°C and the liquefied condenser has a pressure of 50 to 100 kPa; the washing tower has an operating pressure of 0.5 to 1.0 MPaG and the mass ratio of the washing water in the washing tower to the C4 raw material is 1 to 5:1; the raw material tank has an operating pressure of 0.5 to 1.0 MPaG; In step (2), the C4 raw material is pressurized to 1.0 to 4.0 MPaG by a supply pump; The first stage reactor operates at an inlet temperature of 5-60°C for 10-50 hours. -1 It has a liquid space velocity; the first-stage reactor has a reaction pressure of 1.0 to 4.0 MPaG, which is controlled by pressure-compensating hydrogen gas in the buffer tank at the outlet of the first-stage reactor; In process (4), the stabilization tower has an operating pressure of 0.4 to 1.0 MPaG, a theoretical stage number of 10 to 40, and theoretical stage positions of 5 to 35 for recovering side draws.

[0076] Another aspect of the present invention is an apparatus for selective hydrogenation of butadiene extract tail gas, used to carry out the method for selective hydrogenation of butadiene extract tail gas of the present invention, characterized by comprising a raw material tank, a feed pump, a coalescer, a first-stage mixer, a first-stage reactor, a first-stage reactor outlet buffer tank, a circulating C4 cooler, a stabilization tower, and a hydrogen gas supply pipeline; The raw material tank, supply pump, coalescer, first-stage mixer, first-stage reactor, and first-stage reactor outlet buffer tank are connected in order; The outlet pipeline of the buffer tank outlet of the first-stage reactor is divided into at least two paths: the first path is connected in sequence to the circulating C4 cooler, the first-stage mixer, and the first-stage reactor; and the second path is connected directly or indirectly to the stabilization tower; The hydrogen gas supply pipeline is divided into at least a first pipeline and optionally a second pipeline, the first pipeline being connected to the first-stage reactor outlet buffer tank and the second pipeline being connected to the first-stage mixer; Preferably, the first-stage reactor is a fixed-bed reactor; Preferably, the apparatus is provided in which the first path is connected to a circulating C4 cooler via a circulation pump.

[0077] In the present invention, the raw material tank is equipped with a butadiene extraction tail gas supply port and a diluent C4 port.

[0078] In one embodiment, the diluent C4 port of the raw material tank may be connected to the outlet of a stabilization tower, preferably the outlet of the stabilization tower is connected to the diluent C4 port via a diluent C4 pump and / or diluent C4 cooler.

[0079] In one embodiment, the diluent C4 port of the raw material tank may be connected to the outlet pipeline of the first-stage reactor outlet buffer tank, and preferably, a diluent C4 cooler is further provided between the diluent C4 port of the raw material tank and the outlet pipeline of the first-stage reactor outlet buffer tank.

[0080] In one embodiment, the top outlet of the stabilization tower is connected in order to a top condenser, a reflux tank, and a reflux pump, and the outlet of the reflux pump is connected to the inlet of the stabilization tower.

[0081] In one embodiment, the top outlet of the stabilization tower is connected in order to a top condenser, a reflux tank, and a reflux pump, the outlet of the reflux tank is connected to a tail gas condenser, the outlet of the tail gas condenser is connected to the inlet of the reflux tank, and another outlet of the reflux tank is connected to the inlet of the stabilization tower via a reflux pump.

[0082] According to the present invention, the selective hydrogenation apparatus for butadiene extract tail gas may further include, in sequence, a blower suction tank, a blower, a liquefaction condenser, a C4 collection tank, a booster pump, and a scrubbing tower, the C4 raw material outlet of the scrubbing tower being connected to a raw material tank.

[0083] In one embodiment, the outlet of the stabilization tower is connected to the diluent C4 port of the blower suction tank.

[0084] In one embodiment, the washing tower has a washing water inlet and a C4 raw material outlet at the top, and a liquefied C4 raw material inlet and a washing water outlet at the bottom, and a booster pump is connected to the liquefied C4 raw material inlet.

[0085] According to the present invention, the selective hydrogenation apparatus for butadiene extract tail gas may further include a second-stage feed cooler, a second-stage mixer, a second-stage reactor, and a second-stage reactor outlet buffer tank, in which a second path of the outlet pipeline of the first-stage reactor outlet buffer tank is connected to the second-stage feed cooler, and the second-stage reactor outlet buffer tank is connected to a stabilization tower; preferably, the second path is connected to the second-stage feed cooler via a circulation pump; preferably, the second-stage reactor is a fixed-bed reactor.

[0086] In one embodiment, the hydrogen gas supply pipeline is divided into at least a first pipeline, optionally a second pipeline, and a third pipeline, the first pipeline being connected to a buffer tank at the outlet of the first stage reactor, the second pipeline being connected to a first stage mixer, and the third pipeline being connected to a second stage mixer; preferably, the hydrogen gas supply pipeline may further include a pressure compensation pipeline connected to a buffer tank at the outlet of the second stage reactor.

[0087] In one embodiment, the outlet pipeline of the first-stage reactor outlet buffer tank is divided into two paths: the first path is connected sequentially to the circulating C4 cooler, the first-stage mixer, and the first-stage reactor, while the second path is directly connected to the stabilization tower.

[0088] In one embodiment, the outlet pipeline of the first-stage reactor outlet buffer tank is divided into three paths: the first path is connected in order to the circulating C4 cooler, the first-stage mixer, and the first-stage reactor; the second path is connected to the second-stage supply cooler; and the third path is connected to the diluent C4 port of the raw material tank; the hydrogen gas supply pipeline is divided into at least a first pipeline, optionally a second pipeline, and a third pipeline: the first pipeline is connected to the first-stage reactor outlet buffer tank; the second pipeline is connected to the first-stage mixer; and the third pipeline is connected to the second-stage mixer.

[0089] In a specific embodiment, the present invention provides an apparatus for selective hydrogenation of butadiene extract tail gas, used to carry out the method for selective hydrogenation of butadiene extract tail gas of the present invention, characterized by comprising a raw material tank, a feed pump, a coalescer, a first-stage mixer, a first-stage reactor, a first-stage reactor outlet buffer tank, a circulating C4 cooler, a stabilization tower, and a hydrogen gas supply pipeline; The raw material tank, supply pump, coalescer, first-stage mixer, first-stage reactor, and first-stage reactor outlet buffer tank are connected in order; The outlet pipeline of the buffer tank at the outlet of the first-stage reactor is divided into two paths: the first path connects sequentially to the circulating C4 cooler, the first-stage mixer, and the first-stage reactor; and the second path connects to the stabilization tower. The apparatus provides a hydrogen gas supply pipeline that is divided into at least a first pipeline and optionally a second pipeline, the first pipeline being connected to a buffer tank at the outlet of the first-stage reactor and the second pipeline being connected to a first-stage mixer.

[0090] In a preferred embodiment, the outlet of the stabilization tower is connected to the diluent C4 port of the raw material tank.

[0091] In a preferred embodiment, the outlet of the stabilization tower, the diluent C4 pump, the diluent C4 cooler, and the diluent C4 port of the raw material tank are connected in order.

[0092] In a preferred embodiment, the first path of the outlet pipeline of the reactor outlet buffer tank is connected to a circulating C4 cooler via a circulation pump.

[0093] In a specific embodiment, the present invention relates to an apparatus for selective hydrogenation of butadiene extract tail gas, used to carry out the method for selective hydrogenation of butadiene extract tail gas of the present invention, characterized by comprising a raw material tank, a feed pump, a coalescer, a first-stage mixer, a first-stage reactor, a first-stage reactor outlet buffer tank, a circulating C4 cooler, a second-stage feed cooler, a second-stage mixer, a second-stage reactor, a second-stage reactor outlet buffer tank, a stabilization tower, and a hydrogen gas supply pipeline; The raw material tank, supply pump, coalescer, first-stage mixer, first-stage reactor, and first-stage reactor outlet buffer tank are connected in order; The second-stage supply cooler, second-stage mixer, second-stage reactor, second-stage reactor outlet buffer tank, and stabilization tower are connected in order; The raw material tank is equipped with a butadiene extraction tail gas inlet and a diluent C4 port; The outlet pipeline of the buffer tank outlet of the first-stage reactor is divided into three paths: the first path connects sequentially to the circulating C4 cooler, the first-stage mixer, and the first-stage reactor; the second path connects to the second-stage feed cooler; and the third path connects to the diluent C4 port of the raw material tank. The apparatus provides a hydrogen gas supply pipeline that is divided into at least a first pipeline, optionally a second pipeline, and a third pipeline, the first pipeline being connected to the first-stage reactor outlet buffer tank, the second pipeline being connected to the first-stage mixer, and the third pipeline being connected to the second-stage mixer.

[0094] In a preferred embodiment, a first route of the outlet pipeline of the first-stage reactor outlet buffer tank is connected to a circulating C4 cooler via a circulation pump; and a second route of the outlet pipeline of the first-stage reactor outlet buffer tank is connected to a second-stage supply cooler via a circulation pump.

[0095] In a preferred embodiment, a diluent C4 cooler is further provided between the outlet of the first-stage reactor outlet buffer tank and the diluent C4 port of the raw material tank.

[0096] In a preferred embodiment, the hydrogen gas supply pipeline further includes a pressure compensation pipeline connected to the second-stage reactor outlet buffer tank.

[0097] In a specific embodiment, the present invention relates to an apparatus for selective hydrogenation of butadiene extract tail gas, used to carry out the method for selective hydrogenation of butadiene extract tail gas of the present invention, characterized by comprising a blower suction tank, a blower, a liquefaction condenser, a C4 collection tank, a booster pump, a water scrubbing tower, a raw material tank, a feed pump, a coalescer, a first-stage mixer, a first-stage reactor, a first-stage reactor outlet buffer tank, a circulating C4 cooler, a stabilization tower, and a hydrogen gas supply pipeline; The blower suction tank, blower, liquefied condenser, C4 collection tank, booster pump, and scrubbing tower are connected in order; The C4 raw material outlet of the washing tower, raw material tank, supply pump, coalescer, first-stage mixer, first-stage reactor, and first-stage reactor outlet buffer tank are connected in order; The outlet pipeline of the buffer tank at the outlet of the first-stage reactor is divided into two paths: the first path connects sequentially to the circulating cooler, the first-stage mixer, and the first-stage reactor; and the second path connects to the stabilization tower. The apparatus provides a hydrogen gas supply pipeline that is divided into at least a first pipeline and optionally a second pipeline, the first pipeline being connected to a buffer tank at the outlet of the first-stage reactor and the second pipeline being connected to a first-stage mixer.

[0098] In a preferred embodiment, the outlet of the stabilization tower is connected to the diluent C4 port of the blower suction tank.

[0099] In a preferred embodiment, the washing tower has a washing water inlet and a C4 raw material outlet at the top, and a liquefied C4 raw material inlet and a washing water outlet at the bottom, and a booster pump is connected to the liquefied C4 raw material inlet.

[0100] In a preferred embodiment, the first path of the outlet pipeline of the first-stage reactor outlet buffer tank is connected to a circulating cooler via a circulation pump. [Examples]

[0101] The present invention is further illustrated by the following embodiments. <Example 1> As shown in Figure 1, this embodiment provides an apparatus for the selective hydrogenation of butadiene extract tail gas, the apparatus comprising a raw material tank 11, a feed pump 12, a coalescer 13, a first-stage mixer 14, a first-stage reactor 15, a first-stage reactor outlet buffer tank 16, a circulation pump 17, a circulation C4 cooler 18, a diluent C4 cooler 19, a stabilization column 110, a top condenser 111, a reflux tank 112, a reflux pump 113, a tail gas condenser 114, a diluent C4 pump 115, and a hydrogen gas supply pipeline 116; Here, the raw material tank 11 is equipped with a butadiene extract tail gas inlet and a diluent C4 port, and the bottom of the raw material tank 11, the supply pump 12, the coalescer 13, the first-stage mixer 14, the first-stage reactor 15, and the first-stage reactor outlet buffer tank 16 are connected in order; The outlet pipeline of the first-stage reactor outlet buffer tank 16 is divided into two paths: the first path connects sequentially to the circulating C4 cooler 18, the first-stage mixer 14, and the first-stage reactor 15; the second path connects to the stabilization tower 110; and the first path of the outlet pipeline of the first-stage reactor outlet buffer tank 16 is connected to the circulating C4 cooler 18 via the circulating pump 17; The hydrogen gas supply pipeline 116 is divided into at least a first pipeline and optionally a second pipeline, where the first pipeline is connected to the top inlet of the first-stage reactor outlet buffer tank 16, and the second pipeline is connected to the first-stage mixer 14; The stabilization tower 110, the diluent C4 pump 115, the diluent C4 cooler 19, and the outlet of the diluent C4 port of the raw material tank 11 are connected in order; the top outlet of the stabilization tower 110 is connected in order to the top condenser 111 and the reflux tank 112; the outlet of the reflux tank 112 is connected to the tail gas condenser 114, and the outlet of the tail gas condenser 114 is connected to the inlet of the reflux tank 112; the other outlet of the reflux tank 112 is connected to the reflux pump 113; and the outlet of the reflux pump 113 is connected to the inlet of the stabilization tower 110; Hydrogenation reactor 15 was a fixed-bed reactor.

[0102] The apparatus for selective hydrogenation of butadiene extract tail gas in this embodiment was used to carry out a method for selective hydrogenation of butadiene extract tail gas, the selective hydrogenation method comprising: (1) Alkyne-containing tail gas 1101 derived from the butadiene extraction unit (based on the total weight of the alkyne-containing tail gas, the main components of the alkyne-containing tail gas are butene 58.69%, butadiene 10.35%, ethyl acetylene 17.65%, and vinyl acetylene 4.00%, with 2.05% being C5 or higher and 0.02% being water) was supplied to the raw material tank 11, and the alkyne-containing tail gas in the raw material tank was diluted with a cooling diluent C4 1102 derived from the side draw of the stabilization tower 110; here, the alkyne-containing tail gas 1101 had a flow rate of 1825 kg / h and a pressure of 0.8 MPaG; after dilution, in the raw material tank 11, the diluent C4 1102 had a flow rate of 500 kg / h, the vinyl acetylene content in the liquid phase was 5.32%, and the vinyl acetylene content in the gas phase was 4.75%.

[0103] (2) The dilution raw material in the raw material tank 11 was pressurized to 2.7 MPaG by a supply pump and then joined with the circulating C4 stream 1109 from the first-stage reactor outlet buffer tank 16 and supplied to the first-stage mixer 14, where it was mixed with hydrogen gas (i.e., hydrogenation reactor raw material 1107 was obtained) and supplied to the first-stage reactor 15 for the hydrogenation reaction, and the first-stage reaction stream (hydrogenation reactor product 1108) obtained by the reaction was supplied to the first-stage reactor outlet buffer tank 16; the circulating C4 stream 1109 had a flow rate of 45,000 kg / h, the mixed C4 feed had a flow rate of 46,825 kg / h and a temperature of 20°C.

[0104] The hydrogen gas required for the reaction in the first-stage reactor 15 was allocated and supplied through the first supply method; The first supply configuration includes the following: all the hydrogen gas necessary for the reaction is supplied through the first-stage reactor outlet buffer tank 16, and then supplied to the first-stage reactor 15 through the first path at the outlet of the first-stage reactor outlet buffer tank 16; here, the pressure of the reaction system is controlled by the hydrogen gas necessary for the reaction in the first-stage reactor 15 through pressure compensation, and the pressure is 2.3 MPaG; the hydrogen gas is supplied to the liquid phase C4 stream through a dissolution method, and then supplied to the hydrogenation reactor together with the reactor's circulating C4 stream 1109, the circulating C4 stream 1109 has a flow rate of 45,000 kg / h, the hydrogen gas dissolved therein has a flow rate of 34.0 kg / h, the hydrogen gas is no longer supplied to the first-stage mixer 14 located at the inlet of the first-stage reactor 15, and the reaction liquid phase is 15h -1 It had a total space velocity; the first-stage reactor 15 had an inlet temperature of 20°C; (3) The buffer tank 16 at the outlet of the first stage reactor had no gas phase discharge, and the liquid phase product was divided into two streams, the first stream being returned to the hydrogenation reactor as the circulating C4 stream 1109, and the second stream being used as the stabilization tower feed 1112; the stabilization tower feed 1112 had a flow rate of 6853 kg / h; (4) The first-stage reaction stream (first-stage reactor product 1108) obtained from the reaction in the first-stage reactor 15 was supplied to the stabilization column 110 through the first-stage reactor outlet buffer tank 16, where it was separated to produce the C4 hydrogenation product 1118; the stabilization column 110 was used to remove the non-condensable gas 1116 from the top of the column, remove the heavy components 1117 from the column kettle, produce the liquid phase C4 hydrogenation product 1118 rich in 1,3-butadiene and monoolefins from the top of the column, and to recover the diluent C4 stream 1102 used to dilute the feedstock as a side draw at a flow rate of 5000 kg / h. The stabilized column 110 had 30 theoretical stages, an operating pressure of 0.5 MPaG, a top temperature of 56.7°C, a column kettle temperature of 100.2°C, a reflux (stabilized column reflux 1115) flow rate of 5600 kg / h, and theoretical stage positions for recovering 25 side draws.

[0105] The results for the mainstream are shown in Table 1.

[0106] The catalysts used in Examples 1 and 2 are as follows: Based on the total weight of the catalyst, the catalyst consisted of the following components: 7 wt% copper, 0.3 wt% iridium, 2 wt% phosphorus, 3 wt% nickel, and the remainder being a support, which was a titania-alumina composite oxide.

[0107] [Table 1]

[0108] Table 1 shows that the 1,3-butadiene content in the product was approximately 10% higher than that in the raw materials, the alkyne content was less than 0.5%, and the total alkyne conversion rate was higher than 97%, thus meeting the raw material requirements for the butadiene extraction unit. <Example 2> As shown in Figure 1, this embodiment had the following differences compared to Embodiment 1: In step (2), the hydrogen gas required for the reaction in the first-stage reactor 15 is allocated and supplied through a second supply method; the second supply method includes: a portion of the hydrogen gas required for the reaction is supplied through the first-stage reactor outlet buffer tank 16, and then supplied to the first-stage reactor 15 through a first path at the outlet of the first-stage reactor outlet buffer tank 16; the rest of the hydrogen gas is supplied through the first-stage mixer 14, and then flows into the first-stage reactor 15; here, the majority of the hydrogen gas is in the first stage The hydrogen gas was supplied through the reactor outlet buffer tank 16, and this portion controlled the pressure of the reaction system through pressure compensation. At the same time, it flowed into the liquid phase C4 stream through a dissolution method and was supplied to the first-stage reactor along with the reactor's circulating C4 stream 1109, which had a flow rate of 32,000 kg / h and dissolved hydrogen gas had a flow rate of 20.0 kg / h; a small amount of hydrogen gas was supplied to the first-stage mixer 14 located at the inlet of the first-stage reactor 15, with a flow rate of 17.0 kg / h.

[0109] The results for the mainstream are shown in Table 2.

[0110] [Table 2]

[0111] Table 2 shows that the 1,3-butadiene content in the product was approximately 7.8% higher than that in the raw materials, the alkyne content was less than 0.5%, and the total alkyne conversion rate was higher than 97%, thus meeting the raw material requirements for the butadiene extraction unit. Compared to Example 1, in this example, hydrogen gas was not completely supplied to the reactor through the dissolution method, resulting in a slightly worse distribution of hydrogen gas than in Example 1. As a result, some of the 1,3-butadiene was consumed by the hydrogenation reaction, and the increase in the 1,3-butadiene content in the product compared to the raw materials decreased. <Example 3> As shown in Figure 2, this embodiment provides an apparatus for the selective hydrogenation of butadiene extract tail gas, the apparatus comprising a raw material tank 21, a feed pump 22, a coalescer 23, a first-stage mixer 24, a first-stage reactor 25, a first-stage reactor outlet buffer tank 26, a circulating C4 cooler 28, a circulating pump 27, a diluent C4 cooler 29, a second-stage feed cooler 210, a second-stage mixer 211, a second-stage reactor 212, a second-stage reactor outlet buffer tank 213, a stabilizing column 214, a top condenser 215, a reflux tank 216, a reflux pump 217, and a hydrogen gas supply pipeline 218; Here, the bottom of the raw material tank 21, the supply pump 22, the coalescer 23, the first-stage mixer 24, the first-stage reactor 25, and the first-stage reactor outlet buffer tank 26 are connected in order; The second-stage supply cooler 210, the second-stage mixer 211, the second-stage reactor 212, the second-stage reactor outlet buffer tank 213, and the stabilization tower 214 are connected in order; The raw material tank 21 is equipped with a butadiene extraction tail gas inlet and a diluent C4 port; The outlet pipeline of the first-stage reactor outlet buffer tank 26 is divided into three paths: the first path connects sequentially to the circulating C4 cooler 28, the first-stage mixer 27, and the first-stage reactor 25; the second path connects to the second-stage supply cooler 210; and the third path connects to the diluent C4 2102 port of the raw material tank 21. The hydrogen gas supply pipeline 218 is divided into at least a first pipeline, optionally a second pipeline, and a third pipeline, the first pipeline being connected to the first-stage reactor outlet buffer tank 26, the second pipeline being connected to the first-stage mixer 24, and the third pipeline being connected to the second-stage mixer 211. The hydrogen gas supply pipeline also includes a pressure compensation pipeline connected to the second-stage reactor outlet buffer tank 213.

[0112] Here, the first route of the outlet pipeline of the first-stage reactor outlet buffer tank 26 is connected to the circulating C4 cooler 28 via the circulation pump 27; The second route of the outlet pipeline from the outlet buffer tank 26 of the first-stage reactor was connected to the second-stage supply cooler 210 via a circulation pump 27.

[0113] A diluent C4 cooler 29 is also provided between the outlet of the buffer tank 26 at the outlet of the first-stage reactor and the diluent C4 port of the raw material tank 21.

[0114] Here, the top outlet of the stabilization tower 214 was connected in order to the top condenser 215, reflux tank 216, and reflux pump 217, and the outlet of the reflux pump 217 was connected to the inlet of the stabilization tower 214.

[0115] Here, both the first-stage reactor 25 and the second-stage reactor 212 were fixed-bed reactors.

[0116] The apparatus for selective hydrogenation of butadiene extract tail gas in this embodiment was used to carry out a method for selective hydrogenation of butadiene extract tail gas, the selective hydrogenation method comprising the following steps: (1) Alkyne-containing tail gas 2101 derived from the butadiene extraction unit (based on the total weight of the alkyne-containing tail gas, the main components of the alkyne-containing tail gas are butene 58.69%, butadiene 10.35%, ethyl acetylene 17.65%, and vinyl acetylene 4.00%, with 2.05% being C5 or higher and 0.02% being water) is supplied to the raw material tank 21, and the alkyne-containing tail gas 2101 in the raw material tank 21 is The mixture was diluted with diluent C4 stream 2102 derived from the buffer tank 26 at the outlet of the first-stage reactor; the alkyne-containing tail gas 2101 had a flow rate of 1825 kg / h, the raw material tank 21 had an operating pressure of 0.5 MPaG, and the diluent C4 stream 2102 had a flow rate of 3000 kg / h; after dilution, the liquid phase vinylacetylene content in the raw material tank was 6.85%, and the gas phase vinylacetylene content was 3.18%.

[0117] (2) The dilution raw material in the raw material tank 21 is pressurized to 2.7 MPaG by the supply pump 22, then mixed with the circulating C4 stream 2109 from the first-stage reactor outlet buffer tank 26, then supplied to the first-stage mixer 24, where it is mixed with hydrogen gas (i.e., the first-stage reactor raw material 2107 is obtained), supplied to the first-stage reactor 25 to carry out the first-stage hydrogenation reaction, and the first-stage reaction stream (first-stage reactor product 2108) obtained from the reaction is supplied to the first-stage reactor outlet buffer tank 26, the circulating C4 stream 2109 has a flow rate of 85,000 kg / h, the mixed C4 feed has a flow rate of 89,759 kg / h, and the temperature is 35°C.

[0118] The hydrogen gas required for the reaction in the first-stage reactor 25 was supplied through a first supply configuration; the first supply configuration included: all the hydrogen gas required for the reaction was supplied through the first-stage reactor outlet buffer tank 26, and then supplied to the first-stage reactor 25 through a first path at the outlet of the first-stage reactor outlet buffer tank 26, where the hydrogen gas required for the reaction in the first-stage reactor 25 controlled the pressure of the reaction system through pressure compensation and pressure, which was 2.2 MPaG, and the hydrogen gas entered the liquid phase C4 stream by dissolution and was supplied to the first-stage reactor 25 together with the circulating C4 stream 2109 of the first-stage reactor 25, which had a flow rate of 85,000 kg / h, and the hydrogen gas dissolved therein had a flow rate of 48.2 kg / h, and the hydrogen gas was no longer supplied to the first-stage mixer 24.

[0119] (3) The buffer tank 26 at the outlet of the first stage reactor had no gas phase discharge, and the liquid phase product was divided into three streams, the first stream being used as a circulating C4 stream 2109 and returned to the first stage reactor 25; the second stream being used as the second stage reactor feed and supplied to the second stage reactor 212 through the second stage feed cooler 210 and the second stage mixer 211 to carry out the second stage hydrogenation reaction; and the third stream being used as a diluent C4 stream 2102 and supplied to the raw material tank 21; the second stream (second stage reactor raw material 2115) used as the second stage reactor feed had a flow rate of 1807 kg / h and a temperature of 35°C.

[0120] The hydrogen gas required for the reaction in the second-stage reactor 212 was supplied through a third supply configuration; this third supply configuration included: all the hydrogen gas required for the reaction was supplied through the first-stage reactor outlet buffer tank 26, and then supplied to the second-stage reactor 212 through a second path at the outlet of the first-stage reactor outlet buffer tank 26; this portion of the hydrogen gas supplied by dissolution had a flow rate of 1.8 kg / h; the second-stage mixer, located at the inlet of the second-stage reactor, no longer contained hydrogen gas.

[0121] (4) The second-stage reaction stream (second-stage reactor product 116) obtained by the reaction in the second-stage reactor 212 is supplied to the stabilization column 214 through the second-stage reactor outlet buffer tank 213, separated by the stabilization column 214, and the C4 olefin product 2122 is recovered as a side draw; here, the second-stage reaction stream obtained by the reaction in the second-stage reactor is supplied to the second-stage reactor outlet buffer tank, the pressure is controlled to 2.2 MPaG, the C4 stream at the bottom of the second-stage reactor outlet buffer tank is supplied to the stabilization column, the non-condensable gas 2121 from the top of the stabilization column is removed, the heavy components 2123 from the column kettle are removed, and high-quality C4 olefin product 2122 is obtained as a side draw. The C4 olefin product 2122 had a flow rate of 1710 kg / h. The stabilization column 214 had 20 theoretical stages, a top temperature of 71.5 °C, a column kettle temperature of 126 °C, and a reflux (stabilization column reflux 2120) flow rate of 2500 kg / h. The stabilization column 214 had an operating pressure of 0.85 MPaG.

[0122] Here, the first-stage reactor 25 and the second-stage reactor 212 each independently had an inlet temperature of 40 °C, the first-stage reactor had a liquid hourly space velocity of 20 h -1 and the second-stage reactor had a liquid hourly space velocity of 3 h -1 ; the first-stage reactor 25 and the second-stage reactor 212 each independently had a pressure of 2.20 MPaG controlled by the pressure-compensating hydrogen gas in the reactor outlet buffer tank.

[0123] The results of the main stream are shown in Table 3.

[0124] For the catalysts used in Examples 3 and 4, they were as follows: Based on the total weight of the catalyst, the catalyst was composed of the following components: Pd with a content of 0.3% by weight, metallic silver with a content of 0.3% by weight, and a carrier as the balance, and the carrier was alumina.

[0125] The olefin yield in Examples 3 and 4 was calculated according to Formula 1 below:

[0126]

number

[0127] In Equation 1: Examples of butenes include butene-1, cis-2-butene, trans-2-butene, and isobutene; Examples of butadiene include 1,3-butadiene and 1,2-butadiene; Examples of alkynes include ethylacetylene and vinylacetylene; Butene content (mol%) at the outlet of the second-stage reactor: The sum of the normalized mol% content of butene-1, cis-2-butene, trans-2-butene, and isobutene after subtracting the hydrogen gas and methane content from the outlet composition of the second-stage reactor.

[0128] [Table 3]

[0129] Table 3 shows that the alkyne content in the product was less than 5 ppm and the diene content was less than 30 ppm. Based on the outlet composition of the second-stage reactor, the olefin yield of the selective hydrogenation reaction reached 99.5%. <Example 4> As shown in Figure 2, this embodiment had the following differences compared to Example 3: In step (2), the hydrogen gas required for the reaction in the first-stage reactor 25 was allocated and supplied through a second supply method; the second supply method included: a portion of the hydrogen gas required for the reaction was supplied through the first-stage reactor outlet buffer tank 26, and then supplied to the first-stage reactor 25 through a first path of the first-stage reactor outlet buffer tank 26; the remaining portion of the hydrogen gas was supplied through the first-stage mixer 24, and then supplied to the first-stage reactor 25; where the majority of the hydrogen gas was supplied through the first-stage reactor outlet Supplied through buffer tank 26, this portion of hydrogen gas controls the pressure of the reaction system through pressure compensation, and at the same time enters the liquid phase C4 stream by dissolution, supplying the circulating C4 stream 2109 of the first-stage reactor 25 to the reactor, which has a flow rate of 52,000 kg / h and the dissolved hydrogen gas therein has a flow rate of 29.0 kg / h; a small amount of hydrogen gas is supplied through the first-stage mixer 24 provided at the inlet of the first-stage reactor 25, with a flow rate of 23.0 kg / h.

[0130] In step (3), the hydrogen gas required for the reaction in the second-stage reactor 212 was allocated and supplied through a fourth supply method; the fourth supply method included: a portion of the hydrogen gas required for the reaction was supplied through the first-stage reactor outlet buffer tank 26, and then supplied to the second-stage reactor 212 through a second path at the outlet of the first-stage reactor outlet buffer tank 26, with the hydrogen gas supplied by the dissolution method having a flow rate of 1.8 kg / h; the rest of the hydrogen gas was supplied through the second-stage mixer 211, and then supplied to the second-stage reactor 212; where the hydrogen gas supplied through the second-stage mixer 211 at the inlet of the second-stage reactor 212 had a flow rate of 1.5 kg / h.

[0131] The results for the mainstream are shown in Table 4.

[0132] [Table 4]

[0133] Table 4 shows that the alkyne and diene content in the product was less than 30 ppm, and the olefin yield reached 93.0% based on the outlet composition of the second-stage reactor. In this example, since hydrogen gas was not fully supplied to the reactor through the dissolution method, the uniform distribution of hydrogen gas was slightly worse than in Example 3, which resulted in some monoolefins undergoing continuous hydrogenation reactions with hydrogen gas to form alkanes, leading to a slight decrease in olefin selectivity. <Example 5> As shown in Figure 3, this embodiment presents an apparatus for the selective hydrogenation of butadiene extract tail gas, the apparatus comprising a blower suction tank 31, a blower 32, a liquefaction condenser 33, a C4 collection tank 34, a booster pump 35, a water washing tower 36, a raw material tank 37, a supply pump 38, a coalescer 39, a first-stage mixer 310, a first-stage reactor 311, a first-stage reactor outlet buffer tank 312, a circulation pump 313, a circulation cooler 314, a stabilization tower 315, a hydrogen gas supply pipeline 320, a top condenser 316, a reflux tank 317, a reflux pump 318, and a tail gas condenser 319; Here, the blower suction tank 31, blower 32, liquefaction condenser 33, C4 collection tank 34, booster pump 35, and water scrubbing tower 36 are connected in order; the blower suction tank 31 is equipped with a butadiene extraction tail gas inlet and a diluent C4 port; The washing tower 36, raw material tank 37, supply pump 38, coalescer 39, first-stage mixer 310, first-stage reactor 311, and the C4 raw material outlet of the first-stage reactor outlet buffer tank 312 are connected in order; here, the washing tower 36 has a washing water inlet and a C4 raw material outlet at the top, and a liquefied C4 raw material inlet and washing water outlet at the bottom, and the booster pump 35 is connected to the liquefied C4 raw material inlet; The outlet pipeline of the first-stage reactor outlet buffer tank 312 is divided into two paths, where the first path is connected in order to the circulating cooler 314, the mixer 310, and the hydrogenation reactor 11, and the second path is connected to the stabilization tower 315, where the first path of the outlet pipeline of the first-stage reactor outlet buffer tank 312 is connected to the circulating cooler 314 via the circulating pump 313; The hydrogen gas supply pipeline 320 is divided into at least a first pipeline and optionally a second pipeline, where the first pipeline is connected to the first-stage reactor outlet buffer tank 312 and the second pipeline is connected to the first-stage mixer 310; Here, the outlet of the stabilization tower 315 was connected to the diluent C4 port of the blower suction tank 31.

[0134] Here, the top outlet of the stabilization tower 315 was connected in order to the top condenser 316 and reflux tank 317; the outlet of the reflux tank 317 was connected to the tail gas condenser 319, the outlet of the tail gas condenser 319 was connected to the inlet of the reflux tank 317, another outlet of the reflux tank 317 was connected to the reflux pump 318, and the outlet of the reflux pump 318 was connected to the inlet of the stabilization tower 315.

[0135] In this case, the first-stage reactor 311 was a fixed-bed reactor.

[0136] The apparatus for selective hydrogenation of butadiene extract tail gas in this embodiment was used to carry out a method for selective hydrogenation of butadiene extract tail gas, the selective hydrogenation method comprising: (1) Alkyne-containing tail gas 3101 derived from the butadiene extraction unit (based on the total weight of the alkyne-containing tail gas, the main components of the alkyne-containing tail gas are butene 58.69%, butadiene 10.35%, ethyl acetylene 17.65%, and vinyl acetylene 4.00%, with 2.05% being C5 or higher and 0.02% being water) had a flow rate of 1825 kg / h and a pressure of 10 kPa, and before the tail gas entered the blower suction tank 31, it was diluted with gas phase C4 product (i.e., diluent C4 stream 3119) produced as a side draw from the stabilization tower, and the diluent C4 stream 3119 had a flow rate of 5000 kg / h. The tail gas was supplied to the blower suction tank 31, where the gas phase was pressurized to 80 kPa by the blower 32. The C4 raw material was cooled to 5°C in the liquefaction condenser 33 using a coolant, then liquefied, and subsequently supplied to the C4 collection tank 34. After being pressurized by the booster pump 35 and supplied to the washing tower 36 from the bottom of the washing tower 36, impurities accompanying the butadiene tail gas were removed, and then supplied to the raw material tank 37 through the top of the washing tower 36. The washing tower 36 had an operating pressure of 0.7 MPaG, a washing water temperature of 40°C, and a flow rate of 8000 kg / h; the raw material tank had a pressure of 0.65 MPaG.

[0137] (2) The C4 raw material in the raw material tank 37 is pressurized to 2.7 MPaG by the supply pump 38 (to obtain C4 feed 3105), then merged with the circulating C4 stream 3109 from the first-stage reactor outlet buffer tank 312, then supplied to the first-stage mixer 310, where it is mixed with hydrogen gas (i.e., to obtain reactor raw material 3107), then supplied to the first-stage reactor 311 for the hydrogenation reaction, and the first-stage reaction stream obtained by the reaction (first-stage reactor product 3108) is supplied to the first-stage reactor outlet buffer tank 312; here, the circulating C4 stream 3109 has a flow rate of 45,000 kg / h, the mixed C4 feed has a flow rate of 51,826 kg / h, and the first-stage reactor has an inlet temperature of 20°C and 20h -1 It had a liquid space velocity of [value].

[0138] The hydrogen gas required for the reaction in the first-stage reactor 311 was allocated and supplied through a first supply mode; the first supply mode included: all the hydrogen gas required for the reaction was supplied through the reactor outlet buffer tank 312, and then supplied to the first-stage reactor 311 through a first path at the outlet of the reactor outlet buffer tank 312; here, the hydrogen gas required for the reaction in the first-stage reactor 311 controlled the pressure of the reaction system through pressure compensation, the pressure being 2.3 MPaG, the hydrogen gas was supplied to the liquid phase C4 stream by dissolution, the reactor's circulating C4 stream 3109 supplied to the first-stage reactor 311, the circulating C4 stream 3109 had a flow rate of 45,000 kg / h, the hydrogen gas dissolved therein had a flow rate of 34.0 kg / h, and the first-stage mixer 310, located at the inlet of the first-stage reactor 311, no longer contained hydrogen gas.

[0139] (3) The buffer tank 312 at the outlet of the first stage reactor had no gas phase discharge, and the liquid phase product was divided into two streams, the first stream being used as a circulating C4 stream 3109 and returned to the hydrogenation reactor 311, and the second stream being used as feed 3112 to the stabilization tower 315, with a flow rate of 6853 kg / h and a temperature of 35°C.

[0140] (4) The first-stage reaction stream (first-stage reactor product 3108) obtained by the reaction in the first-stage reactor 311 was supplied to the stabilization column 315 through the first-stage reactor outlet buffer tank 312, where it was separated to produce the C4 hydrogenation product 3118; the stabilization column 315 was used to remove the non-condensable gas 3116 from the top of the column, remove the heavy components 3117 from the column kettle, recover the liquid-phase C4 hydrogenation product 3118 rich in 1,3-butadiene and monoolefins from the top of the column, and recover the gas-phase diluent C4 stream 3119 used to dilute the feedstock as a side draw at a flow rate of 5000 kg / h. The stabilization tower 15 had 30 theoretical stages, a side draw position at the 25th theoretical stage, an operating pressure of 0.5 MPaG, a top temperature of 56.7°C, a tower kettle temperature of 100.2°C, and a reflux (stabilization tower reflux 3115) flow rate of 5600 kg / h.

[0141] The results for the mainstream are shown in Table 5.

[0142] The catalysts used in Examples 5 and 6 are as follows: Based on the total weight of the catalyst, the catalyst consisted of the following components: 0.3% by weight of Pd, 0.3% by weight of silver metal, and the remainder as a carrier; the carrier was alumina.

[0143] [Table 5]

[0144] Table 5 shows that the 1,3-butadiene content in the product was approximately 13% higher than that in the raw materials, the alkyne content was less than 0.5%, and the total alkyne conversion rate was higher than 97%, thus meeting the raw material requirements for the butadiene extraction unit. <Example 6> As shown in Figure 3, this embodiment had the following differences compared to Example 5: In step (2), the hydrogen gas required for the reaction in the first-stage reactor 311 was allocated and supplied through a second supply method; the second supply method includes: a portion of the hydrogen gas required for the reaction is supplied to the first-stage reactor outlet buffer tank 312, and then supplied to the first-stage reactor 311 through a first path at the outlet of the first-stage reactor outlet buffer tank 312; the rest of the hydrogen gas is supplied to the first-stage mixer 310, and then supplied to the first-stage reactor 311; here, the majority of the hydrogen gas is supplied to the first-stage reactor outlet buffer tank A portion of the hydrogen gas was allocated through the far tank 312, controlling the pressure of the reaction system through pressure compensation, and simultaneously entering the liquid phase C4 stream through a dissolution method, entering the first-stage reactor along the circulating C4 stream 3109 of the reactor, which had a flow rate of 32,000 kg / h, and the hydrogen gas dissolved therein had a flow rate of 20.0 kg / h; a small amount of hydrogen gas was supplied through the first-stage mixer 310 provided at the inlet of the first-stage reactor 311, with a flow rate of 15.5 kg / h.

[0145] The results for the mainstream are shown in Table 6.

[0146] [Table 6]

[0147] Table 6 shows that the 1,3-butadiene content in the product was approximately 11% higher than that in the raw materials, the alkyne content was less than 0.5%, and the total alkyne conversion rate was higher than 97%, thus meeting the raw material requirements for the butadiene extraction unit. Compared to Example 5, in this example, hydrogen gas was not completely supplied to the reactor during the dissolution process, resulting in a slightly worse uniform distribution of hydrogen gas than in Example 5. As a result, some of the 1,3-butadiene was consumed by the hydrogenation reaction, and consequently, the increase in the 1,3-butadiene content in the product compared to the raw materials was reduced.

[0148] Although various embodiments of the present invention have been described illustratively above, the present invention is not limited to these embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A method for selective hydrogenation of butadiene extract tail gas, characterized by comprising the following: (1) Alkyne-containing tail gas derived from the butadiene extraction unit is supplied to the raw material tank, and any impurities entrained in the alkyne-containing tail gas are optionally removed before being supplied to the raw material tank; (2) The C4 raw material in the raw material tank is pressurized by a supply pump to the pressure required for the reaction, then merged with the circulating C4 stream from the buffer tank at the outlet of the first stage reactor, supplied to the first stage mixer to be mixed with hydrogen gas, supplied to the first stage reactor to undergo the first stage hydrogenation reaction, and the first stage reaction stream obtained by the reaction is supplied to the buffer tank at the outlet of the first stage reactor; The hydrogen gas necessary for the reaction in the first-stage reactor is supplied via a first supply method or a second supply method: The first supply configuration includes the provision that all of the hydrogen gas necessary for the first-stage hydrogenation reaction is supplied through the first-stage reactor outlet buffer tank, and then supplied to the first-stage reactor through a first path at the outlet of the first-stage reactor outlet buffer tank; The second supply configuration includes the supply of a portion of the hydrogen gas required for the first-stage hydrogenation reaction through the first-stage reactor outlet buffer tank, and then being supplied to the first-stage reactor through a first path at the outlet of the first-stage reactor outlet buffer tank; and the supply of the remaining portion of the hydrogen gas required for the first-stage hydrogenation reaction through the first-stage mixer to the first-stage reactor; (3) There is no gas phase discharge from the buffer tank at the outlet of the first stage reactor, and the liquid phase product is divided into at least two streams, the first stream being returned to the first stage reactor as the circulating C4 stream, and the second stream being used as feed to the stabilization tower or subjected to further hydrogenation before being supplied to the stabilization tower; (4) The C4 hydrogenation product is recovered after separation in the stabilization tower.

2. The method for selective hydrogenation of butadiene extract tail gas according to claim 1, wherein in step (1), the alkyne-containing tail gas is diluted with a side-draw diluent C4 stream derived from the stabilization tower.

3. The method for selective hydrogenation of butadiene extract tail gas according to claim 1, wherein in step (1), the alkyne-containing tail gas is diluted with a diluent C4 stream derived from the buffer tank at the outlet of the first-stage reactor.

4. A method for selectively hydrogenating butadiene extract tail gas according to any one of claims 1 to 3, wherein in step (2), in the second supply form, the mass ratio of a portion of the hydrogen gas required for the first-stage hydrogenation reaction to the hydrogen gas required for the first-stage hydrogenation reaction is 0.3 or more, and the hydrogen gas required for the first-stage hydrogenation reaction is the sum of a portion of the hydrogen gas required for the reaction and the remaining portion of the hydrogen gas.

5. The selective hydrogenation method for butadiene extract tail gas according to any one of claims 1 to 4, wherein step (3) further hydrogenation of the second stream before it is supplied to the stabilization tower includes the following: The second stream is used as the feed for the second-stage reactor and is supplied to the second-stage reactor through the second-stage feed cooler and the second-stage mixer to carry out the second-stage hydrogenation reaction. The second-stage reaction stream obtained from the reaction in the second-stage reactor then passes through the second-stage reactor outlet buffer tank and enters the stabilization tower.

6. In step (3), the hydrogen gas necessary for the second-stage hydrogenation reaction in the second-stage reactor is supplied through a third or fourth supply method; The third supply configuration includes the provision that all of the hydrogen gas necessary for the second-stage hydrogenation reaction is supplied through the first-stage reactor outlet buffer tank, and then supplied to the second-stage reactor through a second path at the outlet of the first-stage reactor outlet buffer tank; The selective hydrogenation method for butadiene extract tail gas according to claim 5, wherein the fourth supply configuration includes supplying a portion of the hydrogen gas required for the second-stage hydrogenation reaction through the first-stage reactor outlet buffer tank, and then supplying it to the second-stage reactor through a second path at the outlet of the first-stage reactor outlet buffer tank; and supplying the remaining portion of the hydrogen gas required for the second-stage hydrogenation reaction to the second-stage reactor through the second-stage mixer.

7. The selective hydrogenation method for butadiene extract tail gas according to claim 6, wherein in step (3), in the fourth supply form, the mass ratio of a portion of the hydrogen gas required for the second-stage hydrogenation reaction to the hydrogen gas required for the second-stage hydrogenation reaction is 0.3 or more, and the hydrogen gas required for the second-stage hydrogenation reaction is the sum of the portion of the hydrogen gas required for the reaction and the remaining portion of the hydrogen gas.

8. The method for selective hydrogenation of butadiene extract tail gas according to any one of claims 1 to 7, wherein in step (1), the raw material tank has an operating pressure of 0.1 to 1.0 MPaG.

9. In step (2), the C4 raw material in the raw material tank is pressurized to 1.0 to 4.0 MPaG by the supply pump, and the mass flow rate ratio of the circulating C4 stream to the raw material is 5 to 30:1; The first-stage reactor is operated at 5 to 60°C and for 1 to 50 hours. －１ The method for selective hydrogenation of butadiene extract tail gas according to any one of claims 1 to 8, wherein the first-stage reactor has a liquid space velocity of ; the first-stage reactor has a pressure controlled by pressure-compensating hydrogen gas in the outlet buffer tank of the first-stage reactor, and the reaction pressure is 1.0 to 4.0 MPaG.

10. The method for selective hydrogenation of butadiene extract tail gas according to any one of claims 1 to 9, wherein in step (4), the stabilization tower has an operating pressure of 0.4 to 1.2 MPaG, a theoretical stage number of 10 to 40, and a side-draw theoretical stage position of 5 to 35.

11. A method for selectively hydrogenating butadiene extract tail gas according to any one of claims 1 to 2, wherein in step (1), the alkyne-containing tail gas derived from the butadiene extraction unit is supplied to the raw material tank without the impurities being removed from the alkyne-containing tail gas.

12. In step (3), there are no gaseous effluents originating from the buffer tank at the outlet of the first-stage reactor, and the liquid-phase product is divided into two streams, the first stream being returned to the first-stage reactor as the circulating C4 stream, and the second stream being used as feed to the stabilization tower; The method for selective hydrogenation of butadiene extract tail gas according to claim 11, wherein in step (4), the first-stage reaction stream obtained from the reaction in the first-stage reactor is supplied to the stabilization tower through the outlet buffer tank of the first-stage reactor, and the C4 hydrogenation product is recovered by the stabilization tower.

13. The method for selective hydrogenation of butadiene extract tail gas according to claim 12, wherein in step (1), the alkyne-containing tail gas is diluted with a side-draw diluent C4 stream derived from the stabilization tower.

14. In step (1), the raw material tank has an operating pressure of 0.5 to 1.0 MPaG; In step (2), the diluted C4 raw material is pressurized to 1.0 to 4.0 MPaG by the supply pump, and the mass flow rate ratio of the circulating C4 stream to the diluted C4 raw material is 5 to 30:1; The first-stage reactor has an inlet temperature of 5 to 60°C and operates for 1 to 40 hours. －１ The liquid space velocity is such that the first-stage reactor has a pressure controlled by pressure-compensating hydrogen gas in the first-stage reactor outlet buffer tank, and the reaction pressure is between 1.0 and 4.0 MPaG; The method for selective hydrogenation of butadiene extract tail gas according to claim 13, wherein in step (4), the stabilization tower has an operating pressure of 0.4 to 1.0 MPaG, a theoretical stage number of 10 to 40, and a side-draw theoretical stage position of 5 to 35.

15. In step (1), the alkyne-containing tail gas is supplied to the raw material tank, and the alkyne-containing tail gas in the raw material tank is diluted with diluent C4 stream from the first-stage reactor outlet buffer tank; In step (3), the buffer tank at the outlet of the first-stage reactor has no gas phase discharge, and the liquid phase product is divided into three streams, where the first stream is returned to the first-stage reactor as the circulating C4 stream, the second stream is used as feed to the second-stage reactor and is supplied to the second-stage reactor through the second-stage feed cooler and the second-stage mixer to carry out the second-stage hydrogenation reaction, and the third stream is supplied to the raw material tank as the diluent C4 stream to dilute the alkyne-containing tail gas; The hydrogen gas required for the second-stage hydrogenation reaction in the second-stage reactor is supplied through a third or fourth supply method: The third supply configuration includes the provision that all of the hydrogen gas necessary for the second-stage hydrogenation reaction is supplied through the first-stage reactor outlet buffer tank, and then supplied to the second-stage reactor through a second path at the outlet of the first-stage reactor outlet buffer tank; The fourth supply configuration includes the supply of a portion of the hydrogen gas required for the second-stage hydrogenation reaction through the first-stage reactor outlet buffer tank, and then being supplied to the second-stage reactor through a second path at the outlet of the first-stage reactor outlet buffer tank; and the remaining portion of the hydrogen gas required for the second-stage hydrogenation reaction being supplied to the second-stage reactor through the second-stage mixer; The method for selective hydrogenation of butadiene extract tail gas according to claim 11, wherein in step (4), the second-stage reaction stream obtained by the reaction in the second-stage reactor is supplied to the stabilization tower through the second-stage reactor outlet buffer tank, separated by the stabilization tower, and the C4 olefin product is recovered as a side draw.

16. In step (1), the raw material tank has an operating pressure of 0.5 to 1.0 MPaG, and the mass flow rate ratio of the diluent C4 stream to the alkyne-containing tail gas is 1 to 5:1; In step (2), the diluted C4 raw material is pressurized to 1.0 to 4.0 MPaG by the supply pump, and the mass flow rate ratio of the circulating C4 stream to the diluted C4 raw material is 5 to 30:1; In step (4), the stabilization tower has an operating pressure of 0.6 to 1.2 MPaG, a theoretical stage number of 10 to 40, and a side-draw theoretical stage position of 5 to 35; The first-stage reactor and the second-stage reactor each have an inlet temperature of 20 to 60°C, and the first-stage reactor operates for 10 to 50 hours. －１ The liquid space velocity is such that the second stage reactor operates for 1 to 10 hours. －１ The method for selective hydrogenation of butadiene extract tail gas according to claim 15, wherein the liquid space velocity is such that the first-stage reactor and the second-stage reactor each independently have a pressure of 1.0 to 4.0 MPaG, which is controlled by pressure-compensating hydrogen gas in the respective reactor outlet buffer tanks.

17. A method for selective hydrogenation of butadiene extract tail gas according to any one of claims 1 to 10, wherein in step (1), the alkyne-containing tail gas is supplied to a water washing tower to remove impurities entrained in the alkyne-containing tail gas, and then supplied to the raw material tank.

18. In step (1), if the alkyne-containing tail gas is a gas-phase alkyne-containing tail gas, the alkyne-containing tail gas is supplied to a blower suction tank, pressurized by a blower, condensed and liquefied in a liquefaction condenser, then supplied to a C4 collection tank, then pressurized by a booster pump, supplied to the washing tower to remove impurities entrained in the alkyne-containing tail gas, and then supplied to the raw material tank, the selective hydrogenation method for butadiene extract tail gas according to claim 17.

19. The method for selective hydrogenation of butadiene extract tail gas according to claim 18, wherein in step (3), the buffer tank at the outlet of the first-stage reactor does not have gas phase discharge, the liquid phase product is divided into two streams, the first stream is returned to the first-stage reactor as the circulating C4 stream, and the second stream is used as feed to the stabilization tower.

20. The method for selective hydrogenation of butadiene extract tail gas according to claim 19, wherein in step (1), the alkyne-containing tail gas is diluted with a side-draw diluent C4 stream derived from the stabilization tower.

21. In step (1), the blower suction tank has an operating pressure of 0 to 20 kPa, the condensed liquefied gas in the liquefied condenser has a temperature of 0 to 20°C, the liquefied condenser has a pressure of 50 to 100 kPa, the washing tower has an operating pressure of 0.5 to 1.0 MPaG, the mass ratio of the washing water in the washing tower to the C4 raw material is 1 to 5:1, and the raw material tank has an operating pressure of 0.5 to 1.0 MPaG; In step (2), the C4 raw material is pressurized to 1.0 to 4.0 MPaG by the supply pump, and the first-stage reactor is set to an inlet temperature of 5 to 60°C for 10 to 50 hours. －１ The first-stage reactor has a liquid space velocity, and the pressure is controlled by pressure-compensating hydrogen gas in the first-stage reactor outlet buffer tank, with the reaction pressure being 1.0 to 4.0 MPaG; The method for selective hydrogenation of butadiene extract tail gas according to claim 19 or 20, wherein in step (4), the stabilization tower has an operating pressure of 0.4 to 1.0 MPaG, a theoretical stage number of 10 to 40, and a side-draw theoretical stage position of 5 to 35.

22. An apparatus for selective hydrogenation of butadiene extract tail gas, used to carry out the method according to any one of claims 1 to 21, the apparatus comprising a raw material tank, a feed pump, a coalescer, a first-stage mixer, a first-stage reactor, a first-stage reactor outlet buffer tank, a circulating C4 cooler, a stabilization tower, and a hydrogen gas supply pipeline; The raw material tank, the supply pump, the coalescer, the first-stage mixer, the first-stage reactor, and the first-stage reactor outlet buffer tank are connected in order; The outlet pipeline of the outlet buffer tank of the first-stage reactor is divided into at least two paths, the first path being connected in order to the circulating C4 cooler, the first-stage mixer and the first-stage reactor, and the second path being connected directly or indirectly to the stabilization tower; The apparatus wherein the hydrogen gas supply pipeline is divided into at least a first pipeline and optionally a second pipeline, the first pipeline being connected to the first-stage reactor outlet buffer tank and the second pipeline being connected to the first-stage mixer.

23. The apparatus for selective hydrogenation of butadiene extract tail gas according to claim 22, wherein the diluent C4 port of the raw material tank is connected to the outlet of the stabilization tower.

24. The apparatus for selective hydrogenation of butadiene extract tail gas according to claim 22, wherein the diluent C4 port of the raw material tank is connected to the outlet pipeline of the first-stage reactor outlet buffer tank.

25. The top outlet of the stabilization tower is connected in order to a top condenser, a reflux tank, and a reflux pump, and the outlet of the reflux pump is connected to the inlet of the stabilization tower; Apparatus for selective hydrogenation of butadiene extract tail gas according to any one of claims 22 to 24, wherein optionally, the outlet of the reflux tank is connected to a tail gas condenser, and the outlet of the tail gas condenser is connected to the inlet of the reflux tank.

26. A selective hydrogenation apparatus for butadiene extract tail gas according to any one of claims 22 to 25, further comprising, in order, a blower suction tank, a blower, a liquefaction condenser, a C4 collection tank, a booster pump, and a scrubbing tower, wherein the C4 raw material outlet of the scrubbing tower is connected to the raw material tank.

27. Apparatus for selective hydrogenation of butadiene extract tail gas according to claim 22, further comprising a second-stage feed cooler, a second-stage mixer, a second-stage reactor, and a second-stage reactor outlet buffer tank connected in sequence, wherein the second path of the outlet pipeline of the first-stage reactor outlet buffer tank is connected to the second-stage feed cooler, and the second-stage reactor outlet buffer tank is connected to the stabilization tower.

28. The apparatus for selective hydrogenation of butadiene extract tail gas according to claim 22, wherein the hydrogen gas supply pipeline is divided into at least a first pipeline, optionally a second pipeline, and a third pipeline, the first pipeline being connected to the first-stage reactor outlet buffer tank, the second pipeline being connected to the first-stage mixer, and the third pipeline being connected to the second-stage mixer.

29. Apparatus for selective hydrogenation of butadiene extract tail gas according to any one of claims 22 to 25, wherein the outlet pipeline of the outlet buffer tank of the first stage reactor is divided into two paths, the first path being connected in order to the circulating C4 cooler, the first stage mixer, and the first stage reactor, and the second path being directly connected to the stabilization tower.

30. The outlet pipeline of the outlet buffer tank of the first-stage reactor is divided into three paths: the first path is connected in order to the circulating C4 cooler, the first-stage mixer, and the first-stage reactor; the second path is connected to the second-stage supply cooler; and the third path is connected to the diluent C4 port of the raw material tank; Apparatus for selective hydrogenation of butadiene extract tail gas according to any one of claims 27 to 28, wherein the hydrogen gas supply pipeline is divided into at least a first pipeline, optionally a second pipeline, and a third pipeline, the first pipeline being connected to the first stage reactor outlet buffer tank, the second pipeline being connected to the first stage mixer, and the third pipeline being connected to the second stage mixer.

31. Apparatus for selective hydrogenation of butadiene extract tail gas according to claim 26, wherein the outlet pipeline of the outlet buffer tank of the first stage reactor is divided into two paths, the first path being connected in order to the circulating C4 cooler, the first stage mixer, and the first stage reactor, and the second path being connected to the stabilization tower.

32. The apparatus for selective hydrogenation of butadiene extract tail gas according to claim 31, wherein the outlet of the stabilization tower is connected to the diluent C4 port of the blower suction tank.

33. The selective hydrogenation apparatus for butadiene extract tail gas according to claim 31 or 32, wherein the washing tower has a washing water inlet and a C4 raw material outlet at its top, a liquefied C4 raw material inlet and a washing water outlet at its bottom, and the booster pump is connected to the liquefied C4 raw material inlet.

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