CN115991626A - Treatment method and application of high-acetylene carbon four tail gas - Google Patents

Abstract

The invention relates to the field of petrochemical industry, and discloses a method for treating high-acetylene carbon four tail gas and application thereof, wherein the method comprises the following steps: (1) The method comprises the steps of (1) contacting a mixed material containing a raw material containing high alkyne carbon four tail gas and N-methylpyrrolidone with hydrogen, and carrying out hydrogenation reaction under a catalytic hydrogenation reaction condition to obtain a mixture containing a reaction product; (2) The mixture containing the reaction product is separated to obtain a gas phase recovery stream and the reaction product, respectively. According to the method, butadiene is increased, and the high acetylenic carbon four diluted by NMP is used as a hydrogenation raw material, so that the activity and selectivity of a hydrogenation catalyst are improved, the service life of the hydrogenation catalyst is prolonged, the content of butadiene in a hydrogenation product is high, and the carbon four fraction is more reasonably utilized.

Description

Treatment method and application of high-acetylene carbon four tail gas

Technical Field

The invention relates to the field of petrochemical industry, in particular to a method for treating high-alkyne carbon four tail gas and application thereof.

Background

In the process of preparing ethylene by naphtha steam cracking method, the yield of the carbon tetrahydrocarbon can reach 20-25% of the yield of ethylene. The cracking mixture C four contains about 40-60 wt% of 1, 3-butadiene, 0.5-2.0 wt% of Vinyl Acetylene (VA) and Ethyl Acetylene (EA), and the rest is butane, butene and a small amount of 1, 2-butadiene, C three and C five, wherein the most valuable component is 1, 3-butadiene.

The cracking mixed carbon four is industrially refined by two-stage solvent extraction and rectification and direct rectification processes to obtain a butadiene product, and the butadiene yield is usually 97-98.5%. The separated alkyne contains 20-40wt% of VA and EA and 3-60wt% of 1, 3-butadiene, and the material is so-called high alkyne carbon four, and in industrial production, the material is usually diluted by a carbon four fraction and then treated by a torch for causing resource waste and environmental pollution due to the consideration of safety factors.

The selective hydrogenation method is adopted to treat the manyflower tetraine, so that the method is a good way for avoiding resource waste and environmental pollution. Namely, alkyne in a C4 material flow is converted into butadiene, butene and a small amount of butane through hydrogenation reaction by using a selective hydrogenation catalyst, the hydrogenation reaction is exothermic reaction, a large amount of heat is released in the reaction process, so that the temperature of a catalyst bed layer is rapidly increased, and in addition, polymerization reaction is easy to occur on the catalyst due to unstable substances such as vinyl acetylene, butadiene and the like in the C4 material flow, so that the catalyst is coked and deactivated. The exothermic hydrogenation reaction causes the reaction temperature to be increased, the polymer deposition speed is further accelerated, and the alkyne selective hydrogenation process is extremely unsafe to operate and the service life of the catalyst is short. The consequences will be more severe if the alkyne and butadiene concentrations in the C4 stream are higher. Therefore, it is important to select an appropriate selective hydrogenation alkyne removal process.

The existing process flow of the high acetylenic carbon four selective hydrogenation is shown in figure 2. The high alkyne C4 and hydrogen 1 from the butadiene extraction device and the recycle stream 4 are charged into one or more sections of reactors I connected in series, so that the high alkyne C4 stream is converted into a low-concentration alkyne C4 stream, and if the sections of reactors connected in series are adopted, a cooler is arranged between the sections of the reactors, and a proper amount of hydrogen is added. The hydrogenated material flow 3 is sent into a vapor-liquid separation tank II, a part of material flow 4 of the liquid material flow of the vapor-liquid separation tank is circulated back to the inlet of the first section/the former sections of reactor I through a pump for diluting the high acetylenic carbon four 2, and the other part of material flow 5 is a hydrogenation product and can be used as a raw material of a butadiene extraction device. The non-condensable gas phase stream 6 from the vapor-liquid separation tank is sent to a recovery system.

CN110963878A discloses a method for recovering C4 alkyne tail gas, the C4 alkyne tail gas is produced by a DMF method 1, 3-butadiene extraction device, and impurities in the C4 alkyne tail gas include: butadiene dimer, solvent DMF and water, comprising the steps of: (1) tail gas liquefaction: c4 alkyne tail gas is subjected to two-stage compression boosting through a first section of a compressor and a first section of the compressor; (2) impurity removal: s1, discharging materials of a second-stage cooler of a compressor into a second-stage discharge buffer tank of the compressor to remove impurities to obtain liquefied C4 alkyne materials; s2, mixing the liquefied C4 alkyne material with the residual carbon four, and removing impurities to obtain a coalescer discharge; (3) hydrogenation reaction: mixing the discharged material of the coalescer with hydrogen, and then carrying out selective hydrogenation reaction; (4) light component removal: the hydrogenated material is light, one part of the material is sent to the inlet of the reactor to be used as a circulating diluent, and the other part of the material is sent to a product cooler to be cooled to obtain a hydrogenated product, and the hydrogenated product is sent to a mixed C4 storage tank.

CN108927173a discloses an alkyne hydrogenation selective catalyst, a preparation method and application thereof. The catalyst consists of an active component, a promoting component and a carrier, wherein the active component is palladium, the promoting component which aims at improving the hydrogenation stability and selectivity of the catalyst is added, and the promoting component is introduced into the catalyst in different modes, so that the reasonable regulation and control of the surface acidity of the catalyst are realized, the dispersion of the active component palladium is promoted, and more active sites are formed. The catalyst is suitable for the selective hydrogenation of alkyne-containing materials, especially for the selective hydrogenation of high alkyne-content carbon four materials discharged by a butadiene extraction device, and converts vinyl acetylene and ethyl acetylene into butadiene and butene, and the hydrogenated products are returned to a raw material storage tank or the butadiene extraction device to recover butadiene and butene. The catalyst disclosed by the invention has the advantages of mild hydrogenation reaction conditions, high activity and selectivity, especially good stability and long operation period, and is suitable for hydrogenation of materials with high alkyne content.

CN107522587B discloses a method for recovering 1, 3-butadiene by selective hydrogenation of alkyne in mixed carbon four, comprising the following steps: selecting a hypergravity reactor; inputting hydrogen and a mixed carbon four material into a feeding cavity for gas-liquid two-phase efficient mixing, so that insoluble hydrogen is dispersed into a large number of nano-micron bubbles in the mixed carbon four, and the solubility of the hydrogen in the mixed carbon four is supersaturated to form a gas-liquid mixture; conveying the gas-liquid mixture into a hypergravity reactor through a liquid distributor, and carrying out a gas-liquid-solid catalytic hydrogenation reaction process in a rotor containing a catalyst and a filler; the reaction product and unreacted hydrogen leave the reactor, the product is cooled to room temperature through a condenser and then enters a gas-liquid separation tank, the hydrogen is extracted from the upper part, and a liquid-phase product is extracted from the lower part of the gas-liquid separation tank; the reactor used in the method can enable the solubility of the indissolvable hydrogen in the liquid phase to reach supersaturation, efficiently utilize the hydrogen, strengthen the gas-liquid-solid phase mass transfer, and ensure that the yield of butadiene is not less than 80 percent.

Said invention makes some optimization from two aspects of technological process and hydrogenation catalyst, but uses carbon four and alkyne as raw material, and makes hydrogenation reaction in the presence of hydrogenation catalyst in fixed bed reactor, in the actual process, the service life of catalyst is short, and the hydrogenation method is not improved.

In addition, the present inventors have found through studies that, in the prior art, as the reaction proceeds, the catalyst bed temperature in the feed direction of the materials increases due to the heat evolved from the reaction, and at higher reaction temperatures, the product selectivity decreases due to excessive hydrogenation reactions, and the polymerization of unsaturated carbon four may clog catalyst channels, cover active centers, resulting in a decrease in catalyst life cycle and life.

Therefore, how to provide a new process, to improve the service life and the service life of the catalyst in the process application, is a technical problem to be solved at present.

Disclosure of Invention

Aiming at the problems of the prior art, the invention aims to overcome the defects in the prior art and provide a method for treating high-alkyne carbon four tail gas and application thereof.

The invention aims to provide a method for treating high-acetylene carbon four tail gas, which comprises the following steps of:

(1) The method comprises the steps of (1) contacting a mixed material containing a raw material containing high alkyne carbon four tail gas and N-methylpyrrolidone with hydrogen, and carrying out hydrogenation reaction under a catalytic hydrogenation reaction condition to obtain a mixture containing a reaction product;

(2) The mixture containing the reaction product is separated to obtain a gas phase recovery stream and the reaction product, respectively.

According to the wide application range of the high acetylenic carbon four tail gas source, in a preferred embodiment of the invention, the high acetylenic carbon four tail gas is derived from a residual fraction containing the carbon four acetylenes, which is discharged from an alkyne washing link in a secondary extraction stage of butadiene extraction, and preferably is mainly derived from a residual fraction containing high-concentration vinyl acetylene and ethyl acetylene, which is discharged from an alkyne washing tower of a secondary extraction part of a butadiene extraction device.

According to the invention, the component content of the high-alkyne carbon four tail gas is wide in selection range, and preferably, the high-alkyne carbon four tail gas contains 0-5 wt% of butene, 3-60wt% of 1, 3-butadiene and 20-50 wt% of carbon four alkyne in percentage by weight of carbon four components. In addition, the high acetylenic carbon four tail gas may contain other components, for example, n-butane, isobutane, 1-butene, cis-2-butene, trans-2-butene, isobutene and 1, 2-butadiene, and the contents of these components have little influence on the selective hydrogenation reaction, so that the specific contents of these components are not particularly limited in the present invention.

According to the invention, the carbon tetraacetylene is selected in a wide range, preferably the carbon tetraacetylene comprises vinylacetylene and/or ethylacetylene, i.e. vinylacetylene and ethylacetylene are co-present, or are one of vinylacetylene and ethylacetylene.

The ratio of the N-methyl pyrrolidone to the raw material containing the high acetylenic carbon four tail gas is wider in the selection range, and in a preferred embodiment of the invention, the high acetylenic carbon four and NMP are mixed and then enter a selective hydrogenation reactor I, so that the activity and the selectivity of the catalyst in hydrogenation reaction are improved, and the mass ratio of the N-methyl pyrrolidone to the raw material containing the high acetylenic carbon four tail gas is (0.1-40): 1, preferably (1-20): 1, more preferably (2-10): 1. in this preferred embodiment, the hydrogenation product has a higher butadiene content, better butadiene selectivity, and longer service life and life of the hydrogenation catalyst.

According to the invention, the mass ratio of the N-methyl pyrrolidone to the raw material containing the high acetylenic carbon four tail gas is (0.1-40): 1, preferably (1-20): 1, more preferably (2-10): 1, for example, may be any value or ratio of any two intervals between 2:1, 3:1, 4:1, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1, and 2-10 to 1.

In a preferred embodiment of the invention, the vinyl acetylene content of the feedstock containing the high acetylenic carbon four tail gas before the reaction is 1 to 6 wt%, preferably 2 to 4 wt%, based on 100% of the total weight of the feedstock containing the high acetylenic carbon four tail gas; in this preferred embodiment, the temperature rise can be reduced more effectively, and the service life and the service period of the hydrogenation catalyst can be improved.

According to the invention, the hydrogenation reaction is preferably carried out under continuous feeding of the mixture. Under the condition of continuous feeding, the mixed material can continuously wash the catalyst, so that the catalytic activity and selectivity of the catalyst can be further maintained, the activity and selectivity of the catalyst are improved, and the service life and period of the catalyst are further prolonged compared with the prior art.

The vinyl acetylene content in the raw material of the high acetylene carbon four tail gas can be controlled through dilution, and the source of the diluted material is not particularly limited. Under the hydrotreating conditions adopted in the hydrogenation reaction, the hydrogenated carbon four fraction contains only a small amount of alkyne, and can be returned to serve as a raw material of a butadiene extraction device. Preferably, hydrogenation products are obtained after selective hydrogenation reaction, part of the hydrogenation products are returned to the inlet of the hydrogenation reactor as recycle streams to dilute the concentration of alkyne in the high alkyne carbon four, and the rest is taken as products.

In a preferred embodiment of the invention, the method further comprises step (3): returning a part of the reaction product obtained in the step (2) to the step (1) as a circulating material so as to dilute alkyne in the high-alkyne carbon four tail gas in the step (1) before hydrogenation; other reaction products are withdrawn. Therefore, dilution gas is not required to be additionally introduced, dilution of the high acetylene carbon four tail gas can be realized in the process flow, the vinyl acetylene content in the raw materials is controlled in a preferred range, and the process flow is more economical.

According to the invention, the catalytic hydrogenation reaction conditions are selected in a wide range. In a preferred embodiment of the present invention, the catalytic hydrogenation reaction conditions comprise: the temperature of the hydrogenation reaction is 20-80 ℃.

According to the invention, the molar ratio of hydrogen to alkyne content in the mixture before reaction can also be adjusted within a relatively wide range. In a preferred embodiment of the invention, the molar ratio of hydrogen to alkyne content in the mixture before reaction is (0.5-2): 1.

according to the invention, the catalytic hydrogenation reaction pressure is selected in a wide range, and in a preferred embodiment of the invention, the reaction pressure is 0.6-4MPa; preferably, the liquid space velocity is 1-100h ^-1 。

According to the present invention, the hydrotreating conditions employed in the selective hydrogenation reactor may be appropriately changed depending on the composition properties of the carbon four fraction stream to be treated and the proportion of NMP to be incorporated, and the temperature is as low as possible to further prevent polymerization of unsaturated hydrocarbons in the carbon four fraction. In a more preferred embodiment of the present invention, the conditions include: the inlet temperature of the reactor is 20-80 ℃, and the molar ratio of hydrogen at the inlet to alkyne content in the mixture flow is 0.5-2:1, the reaction pressure is 0.6-4MPa, and the liquid space velocity is 1-100h ^-1 。

The catalyst used in the catalytic hydrogenation reaction according to the present invention may be a catalyst conventional in the art, and in a preferred embodiment of the present invention, the catalyst used in the catalytic hydrogenation reaction is a supported hydrogenation catalyst, preferably the supported hydrogenation catalyst comprises a support and an active metal component supported on the support and optionally an auxiliary agent.

For the component content of the supported hydrogenation catalyst, the selection range is wide, and preferably, in the supported selective hydrogenation catalyst, the content of the active metal component in terms of elements may be 0.008 to 1% by weight, preferably 0.01 to 0.5% by weight, based on the total weight of the catalyst; the content of the auxiliary agent may be 0 to 10% by weight, based on the element.

According to the present invention, the active metal component is selected from a wide range, and in a preferred embodiment of the present invention, the active metal component is selected from at least one of palladium, platinum, and nickel.

According to the invention, the auxiliary agent is selected from a wide range of choices, and in a preferred embodiment of the invention, the auxiliary agent is selected from at least one of potassium, sodium, lithium, calcium, magnesium, barium, fluorine, copper, silver, gold, zinc, tin, lead, manganese, bismuth, molybdenum, zirconium and rare earth elements.

According to the present invention, the carrier is selected from a wide range, and in a preferred embodiment of the present invention, the carrier is selected from at least one of alumina, silica, spinel, diatomaceous earth, titania, zinc oxide, tin oxide, and molecular sieves.

Preferably, in order to provide the supported selective hydrogenation catalyst with the advantages of higher activity, better selectivity and longer service life, the supported selective hydrogenation catalyst may contain a carrier, an active metal component and an auxiliary agent, wherein the active metal component may contain at least palladium, the auxiliary agent may contain at least silver or lead, and the carrier may be alumina.

According to the invention, the catalyst has a relatively wide range of parameters such as bulk density, specific surface area, etc., and in a preferred embodiment of the invention, the catalyst has a bulk density of 0.5-1.5g/cm ³ And/or a specific surface area of 5-350m ² /g。

In the supported selective hydrogenation catalyst according to the present invention, the shape of the support may be a conventional choice in the art. For example, the carrier may be one or more of spherical, cylindrical, clover, toothed, or extruded. The bulk density of the catalyst may be in the range of 0.5 to 1.5g/cm ³ When the carrier is spherical, cylindrical or extruded, the diameter (spherical diameter or cylindrical diameter or extruded diameter) of the catalyst may be 1-6mm, and the specific surface area may be 5-350m ² /g。

The preparation method of the supported selective hydrogenation catalyst according to the present invention may be a method well known to those skilled in the art. The production method includes, for example, a step of loading components including the active component on a catalyst carrier and then calcining; wherein the support can be carried on the catalyst carrier by impregnating or spraying components including active component solutions.

According to the invention, in order to realize the selective hydrogenation method of the alkyne in the high alkyne carbon four, the method is carried out in a reaction device comprising a selective hydrogenation reactor I, wherein the reactor is an adiabatic fixed bed reactor or a tubular isothermal fixed bed reactor, and the reactant flow direction is from top to bottom or from bottom to top.

According to the present invention, the hydrogenation technique may take the form of a suitable reactor, for example, the hydrogenation reactor may be an adiabatic or isothermal fixed bed reactor, more preferably the fixed bed hydrogenation reactor may be a bubbling bed reactor (material flow from bottom to top) or a trickle bed reactor (material flow from top to bottom).

In a more preferred embodiment of the present invention, as shown in FIG. 1, a process for the selective hydrogenation of acetylenes in a higher acetylenic carbon tetraline, the process being carried out in a fixed bed hydrogenation reactor I, the process comprising: mixing the high alkyne carbon four material flow 1 with N-methyl pyrrolidone 3, diluting with a circulating material 5 which is circulated and returned, then adding a metered hydrogen material flow 2, entering a hydrogenation reactor I for selective hydrogenation reaction to obtain a hydrogenation product 4, separating the hydrogenation product by a separating tank II, wherein part of the hydrogenation product is returned to the inlet of the hydrogenation reactor as a circulating material 5 so as to dilute the alkyne concentration in the high alkyne carbon four, extracting the rest as a product 6, and extracting a gas-phase recovery material flow 7 from the upper part. As shown in fig. 2, the catalyst hydrogenation reaction does not contain N-methylpyrrolidone 3.

It is a further object of the present invention to provide the use of the method described above for the selective hydrogenation of alkynes in the high acetylenic carbon tetra tail gas.

Compared with the prior art, the invention has the following advantages:

(1) The process according to the invention carries out catalytic hydrogenation, the content of vinylacetylene in the hydrogenated product is not more than 1.5% by weight, preferably not more than 1.3% by weight, the selectivity of hydrogenation of vinylacetylene to 1, 3-butadiene is not less than 50%, and the content of 1, 3-butadiene in the product is significantly increased. The butadiene content in the hydrogenation product is increased, so that the carbon four fraction is more reasonably utilized.

(2) The service life and the service period of the hydrogenation catalyst are obviously prolonged.

(3) The catalytic hydrogenation process is simple and controllable, and has high popularization and application value.

The inventor of the present invention has found that, in the prior art, along the feeding direction of the materials, as the reaction proceeds, the temperature of the catalyst bed is increased due to the heat released by the reaction, at higher reaction temperatures, the selectivity of the product is reduced due to excessive hydrogenation reaction, and the polymerization of unsaturated carbon four can block the catalyst pore canal and cover the active center, resulting in the reduction of the service life and the service life of the catalyst.

According to the invention, NMP is added in the hydrogenation process, and the inventor of the invention surprisingly discovers that the service life and the service period of the hydrogenation catalyst are obviously prolonged, and the catalytic technical effect is better than that of the prior art, namely, the hydrogenation reaction of the high acetylenic carbon four fraction in the presence of NMP is carried out, so that the activity of hydrogenation catalysis is not reduced or deactivated, and the selectivity of 1, 3-butadiene is improved. Through further research, the inventors of the present invention considered that the reason is that since NMP is in a continuously flowing state, scouring of the catalyst surface is enabled, the coking amount of the catalyst surface is significantly reduced, and furthermore, addition of NMP also enables reduction of the temperature rise.

In the method provided by the invention, the high alkyne carbon four raw material flow and the NMP flow are mixed and then subjected to hydrogenation reaction, and finally the target carbon four fraction product is obtained, because the alkyne concentration is reduced after the carbon four fraction is diluted by the NMP, the temperature rise in the hydrogenation process can be greatly reduced, the excessive hydrogenation reaction is inhibited, the selectivity of the hydrogenation catalyst is improved, and meanwhile, the deposition of the polymer on the surface of the catalyst is greatly reduced due to the continuous scouring of the NMP on the surface of the catalyst, so that the service cycle of the hydrogenation catalyst can be prolonged.

Drawings

FIG. 1 is a schematic flow chart of a selective hydrogenation method of alkyne in a high alkyne carbon four tail gas;

fig. 2 is a schematic flow chart of a process for selective hydrogenation of alkynes in the high alkyne carbon four tail gas described in comparative example 1.

Description of the reference numerals

1. High acetylenic carbon four stream

2. Hydrogen stream

3. N-methylpyrrolidone

4. Hydrogenation product

5. Circulating material

6. Product(s)

7. Vapor recovery stream

I. Selective hydrogenation reactor

II. Separating tank

Detailed Description

The present invention is described in detail below with reference to the specific drawings and examples, and it is necessary to point out that the following examples are given for further illustration of the present invention only and are not to be construed as limiting the scope of the present invention, since numerous insubstantial modifications and adaptations of the invention to those skilled in the art will still fall within the scope of the present invention.

In the following examples and comparative examples, the content of alkyne, alkene and alkane components in the carbon four fraction was measured by a gas chromatograph model 7890 available from Yu Anjie rennet; the content of alkyne, alkene and alkane components in the hydrogenation product is calculated by normalization after subtracting the NMP and hydrogen contents.

In each of the following examples and comparative examples, the inlet temperature and outlet temperature of each hydrogenation reactor were measured by thermocouples.

In the following examples and comparative examples, N-methylpyrrolidone was obtained from commercial sources.

Example 1

The raw materials adopted in the embodiment are high alkyne carbon four tail gas discharged by a butadiene extraction device, the specific content of each component corresponding to the high alkyne tail gas in the table 1 is shown in the specification, the catalyst adopts palladium-silver supported hydrogenation catalyst, and the catalyst carrier is Al ₂ O ₃ The active metal component content is: 0.3 wt% palladium and 0.15 wt% silver; loading the active components on the carrier by isovolumetric impregnation, oven drying at 120deg.C for 6hr, and thenDecomposing in air at 450deg.C for 8hr; the catalyst was reduced in a reactor at 100-120 ℃ for 4hr with hydrogen gas. The hydrogenation reactor was a trickle bed reactor filled with 50ml of catalyst using the process flow shown in figure 1. Taking the total weight of the high acetylenic carbon four-fraction raw material from the butadiene extraction device as a standard, mixing 2 parts by weight of NMP with the total weight of the high acetylenic carbon four-fraction raw material into a selective hydrogenation reactor I, wherein the weight ratio of the feeding amount of NMP to the feeding amount of the high acetylenic carbon four-fraction raw material stream in the material entering the selective hydrogenation reactor I is 2:1. the inlet temperature of the selective hydrogenation reactor I is 42 ℃, the pressure is 1.0MPa, and the molar ratio of hydrogen at the inlet to alkyne content in the mixture stream is 0.86:1, the vinyl acetylene content at the reactor inlet was 3.12% by weight based on the total of the four carbon components, and the liquid space velocity (LHSV) calculated on the basis of the four carbon feeds at the reactor inlet was 40h ^-1 ；

The hydrogenation reaction is carried out according to the conditions, the reaction mixture enters a separation tank II, a gas-phase recovery material flow is obtained above the separation tank II through separation, a hydrogenation product is obtained below the separation tank II, part of the hydrogenation product is returned to the inlet of the hydrogenation reactor as a circulation material flow so as to dilute the concentration of alkyne in high alkyne C4, the vinyl acetylene content at the inlet of the reactor is controlled within a target range of 2% -4%, and the rest is taken out as a product, and the result is shown in Table 1.

Example 2

This example uses the same high alkyne tail gas and catalyst as in example 1 for the hydrogenation reaction. Specifically, the hydrogenation reactor was a trickle bed reactor filled with 50ml of catalyst using the process flow shown in FIG. 1. Based on the total weight of the high acetylenic carbon four raw materials discharged from the butadiene extraction device, 4 parts by weight of NMP is mixed with the high acetylenic carbon four raw materials and enters a selective hydrogenation reactor I, namely the weight ratio of the NMP to the high acetylenic carbon four fraction raw material flow in the materials entering the selective hydrogenation reactor I is 4:1. the inlet temperature of the selective hydrogenation reactor I is 42 ℃, the pressure is 1.0MPa, and the molar ratio of hydrogen at the inlet to alkyne content in the mixture stream is 0.92:1, a vinyl acetylene content of 3.05% by weight at the reactor inlet, a liquid space velocity (LHSV) of 40h calculated on the basis of the carbon four feed at the reactor inlet ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The subsequent separation procedure was the same as in example 1, and the results are shown in Table 1.

Example 3

This example uses the same carbon four feedstock and catalyst as in example 1 for the hydrogenation reaction. Specifically, the hydrogenation reactor was a trickle bed reactor filled with 50ml of catalyst using the process flow shown in FIG. 1. Taking the total weight of the high acetylenic carbon four discharged from a butadiene extraction device produced by a hydrocarbon steam cracking device as a standard, 10 parts by weight of NMP is mixed with the total weight of the high acetylenic carbon four and enters a selective hydrogenation reactor I, namely the weight ratio of the NMP to the feeding amount of the high acetylenic carbon four fraction raw material stream in the material entering the selective hydrogenation reactor I is 10:1. the inlet temperature of the selective hydrogenation reactor I is 42 ℃, the pressure is 1.0MPa, and the molar ratio of hydrogen at the inlet to alkyne content in the mixture stream is 0.90:1, a vinyl acetylene content of 2.98% by weight at the reactor inlet, a liquid space velocity (LHSV) of 20h calculated on the basis of the carbon four feed at the reactor inlet ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The subsequent separation procedure was the same as in example 1, and the results are shown in Table 1.

Example 4

The raw materials adopted in this example are the same as those in example 1, the catalyst adopts palladium-lead selective hydrogenation catalyst, and the catalyst carrier is Al ₂ O ₃ The active metal component content is: 0.3 wt% palladium and 0.1 wt% lead; loading the active components on the carrier by isovolumetric impregnation, oven drying at 120deg.C for 6hr, and decomposing in air atmosphere at 450deg.C for 8hr; the catalyst was reduced in a reactor at 100-120 ℃ for 4hr with hydrogen gas. The hydrogenation reactor was a bubbling bed reactor filled with 50ml of catalyst using the process flow shown in FIG. 1. Based on the total weight of the high acetylenic carbon four discharged from the butadiene extraction device, 10 parts by weight of NMP is mixed with the high acetylenic carbon four and enters a selective hydrogenation reactor I, namely the weight ratio of the NMP to the high acetylenic carbon four fraction raw material flow in the materials entering the selective hydrogenation reactor I is 10:1. the inlet temperature of the selective hydrogenation reactor I is 42 ℃, the pressure is 1.2MPa, and the molar ratio of hydrogen at the inlet to alkyne content in the mixture stream is 0.94:1, the vinyl acetylene content at the reactor inlet was 3.07% by weight, based on the carbon four feed at the reactor inletQuasi-calculated liquid space velocity (LHSV) of 40h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The subsequent separation procedure was the same as in example 1, and the results are shown in Table 1.

Comparative example 1

The same high acetylenic carbon four tail gas and catalyst as in example 1 were used in this comparative example. With the process flow shown in fig. 2, the hydrogenation reactor was a trickle bed reactor filled with 50ml of catalyst. The inlet temperature of the selective hydrogenation reactor I is 40 ℃, the pressure is 1.2MPa, and the molar ratio of hydrogen at the inlet to alkyne content in the mixture stream is 0.83:1, a vinyl acetylene content of 3.07% by weight at the reactor inlet, a liquid space velocity (LHSV) of 40h calculated on the basis of the carbon four feed at the reactor inlet ^-1 The method comprises the steps of carrying out a first treatment on the surface of the The subsequent separation procedure was the same as in example 1, and the results are shown in Table 1.

Test case

The reaction materials (corresponding to Gao Gui off-gas) and results of the above examples and comparative examples, tested according to the method of the present invention described previously, are shown in Table 1. The high alkyne tail gas is taken as 100% of the sum of all the four carbon components, and the products in the examples and comparative examples are taken as 100% of the sum of all the four carbon components.

The method for calculating the selectivity of butadiene comprises the following steps:

TABLE 1

As can be seen from the results of Table 1, according to the method provided by the invention, after NMP is added into the high acetylenic carbon four, the activity and selectivity of the hydrogenation catalyst are improved, and the service life of the hydrogenation catalyst can be prolonged by reasonably selecting the circulation ratio, the flow ratio of NMP and the carbon four fraction raw material flow entering the selective hydrogenation reactor, the hydrogen/acetylenic ratio and the reaction temperature. The content of vinyl acetylene in the hydrogenated target carbon four fraction product is not more than 1.3 weight percent, and the selectivity of 1, 3-butadiene is not less than 50 percent.

As can be seen from comparing example 1 with comparative example 1, the 1, 3-butadiene selectivity of example 1 is significantly higher than that of comparative example 1 with the same total catalyst usage and throughput of the manyflower carbon tetraraw material.

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the scope of the technical idea of the invention, a number of simple variants of the technical solution of the invention are possible, including combinations of the individual technical features in any other suitable way, which simple variants and combinations should likewise be regarded as being disclosed by the invention, all falling within the scope of protection of the invention.

Claims (10)

1. A method for treating high-alkyne carbon four tail gas comprises the following steps:

(1) The method comprises the steps of (1) contacting a mixed material containing a raw material containing high alkyne carbon four tail gas and N-methylpyrrolidone with hydrogen, and carrying out hydrogenation reaction under a catalytic hydrogenation reaction condition to obtain a mixture containing a reaction product;

(2) The mixture containing the reaction product is separated to obtain a gas phase recovery stream and the reaction product, respectively.

2. A processing method according to claim 1, characterized in that:

the high alkyne carbon four tail gas comes from residual fraction containing carbon four alkynes, which is discharged from alkyne washing links in a butadiene extraction and secondary extraction stage;

preferably, the high alkyne carbon four tail gas comprises 0-5 wt% of butene, 3-60wt% of 1, 3-butadiene and 20-50 wt% of carbon four alkyne in percentage by weight of carbon four components;

more preferably, the carbon tetraalkyne comprises vinylacetylene and/or ethylacetylene.

3. A processing method according to claim 1, characterized in that:

the mass ratio of the N-methyl pyrrolidone to the raw materials containing the high alkyne carbon four tail gas is (0.1-40): 1, preferably (1-20): 1, more preferably (2-10): 1.

4. a processing method according to claim 1, characterized by comprising:

the vinyl acetylene content in the raw material containing the high-acetylene carbon four tail gas before the reaction is 1 to 6 weight percent, preferably 2 to 4 weight percent, based on the total weight of the raw material containing the high-acetylene carbon four tail gas as 100 percent;

preferably, the vinyl acetylene content in the raw material containing the high acetylenic carbon four tail gas is controlled by diluting the high acetylenic carbon four tail gas.

5. A process according to any one of claims 1 to 4, characterized in that it further comprises a step (3): returning a part of the reaction product obtained in the step (2) to the step (1) as a circulating material so as to dilute alkyne in the high-alkyne carbon four tail gas in the step (1) before hydrogenation; other reaction products are withdrawn.

6. A process according to any one of claims 1 to 4, characterized in that:

the catalytic hydrogenation reaction conditions include:

the temperature of hydrogenation reaction is 20-80 ℃; and/or the molar ratio of hydrogen to alkyne content in the mixture before reaction is (0.5-2): 1, a step of; and/or the reaction pressure is 0.6-4MPa; and/or a liquid space velocity of 1 to 100h ^-1 。

7. A process according to any one of claims 1 to 4, characterized in that:

the catalyst used in the catalytic hydrogenation reaction is a supported hydrogenation catalyst, and the supported hydrogenation catalyst contains a carrier, an active metal component supported on the carrier and optional auxiliary agents;

preferably, in the supported selective hydrogenation catalyst, the content of the active metal component in terms of elements may be 0.008 to 1 wt%, preferably 0.01 to 0.5 wt%, based on the total weight of the catalyst; the content of the auxiliary agent may be 0 to 10% by weight, based on the element.

8. A processing method according to claim 7, characterized in that:

the active metal component is at least one of palladium, platinum and nickel; and/or the number of the groups of groups,

the auxiliary agent is at least one of potassium, sodium, lithium, calcium, magnesium, barium, fluorine, copper, silver, gold, zinc, tin, lead, manganese, bismuth, molybdenum, zirconium and rare earth elements; and/or the number of the groups of groups,

the carrier is at least one of alumina, silicon oxide, spinel, diatomite, titanium oxide, zinc oxide, tin oxide and molecular sieve; and/or the number of the groups of groups,

the bulk density of the catalyst is 0.5-1.5g/cm ³ And/or a specific surface area of 5-350m ² /g。

9. A process according to any one of claims 1 to 4, characterized in that:

the hydrogenation reactor used in the hydrogenation reaction is an adiabatic fixed bed reactor or a tubular isothermal fixed bed reactor; preferably, the reactant flow direction is from top to bottom or from bottom to top.

10. Use of a treatment process according to any one of claims 1 to 9 for the selective hydrogenation of alkynes in a homoalkynes carbon four tail gas.

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