Acetylene mixed gas recovery method and recovery device

Abstract

The invention provides an acetylene mixed gas recovery method and recovery device, and the recovery method comprises the following steps: carrying out heavy component absorption treatment on acetylene mixed gas by using a first absorption solvent to obtain heavy component-removed mixed gas and a heavy component-rich solvent; carrying out acetylene absorption treatment on the heavy-component-removed mixed gas by using a second absorption solvent to obtain an acetylene-rich solvent and a light component; and carrying out primary acetylene desorption treatment on the acetylene-rich solvent to obtain acetylene, a first acetylene-light component mixed gas and a primary solvent component, and enabling the first acetylene-light component mixed gas and the acetylene mixed gas to jointly participate in heavy component absorption treatment. According to the acetylene recovery method, acetylene in the acetylene mixed gas can be efficiently recovered, and recycling of acetylene is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical recovery, and in particular to a recovery method and a recovery device for acetylene mixed gas. Background Art

[0002] As a basic chemical raw material, acetylene holds an irreplaceable position in industry. Its high calorific value makes it the preferred fuel gas for metal cutting and welding, particularly in shipbuilding and machinery manufacturing. In chemical synthesis, acetylene is a key monomer in the production of vinyl acetate (VAM), used in the production of latex, coatings, and adhesives, and acrylic acid, a key precursor for superabsorbent resins and plastics. Furthermore, demand for acetylene-derived carbon materials (such as carbon fibers and carbon nanotubes) is surging in sectors such as aerospace and new energy batteries.

[0003] The traditional calcium carbide method of producing acetylene relies on the high-temperature reaction of coke and limestone, consuming as much as 12,000 kWh per ton of acetylene and generating significant amounts of carbide slag and CO2 emissions. However, acetylene production from methane-rich gas (natural gas, biogas, coalbed methane) directly converts methane into acetylene, significantly reducing energy consumption (approximately 3,500 kWh per ton) and carbon emissions. This technology also increases raw material utilization to over 80%, aligning with carbon neutrality goals. This technology is particularly suitable for regions rich in natural gas, transforming inexpensive methane resources into high-value-added products and driving the upgrading of the chemical industry chain.

[0004] The core process for producing acetylene from methane-rich gas involves partial oxidation. This involves premixing methane with oxygen, which undergoes partial combustion in a 1400–1600°C combustion chamber. This heat release drives the cracking of the remaining methane, producing syngas containing 8–10% acetylene, H₂, and CO. However, the current recovery rate for acetylene from syngas is too low.

[0005] Therefore, how to efficiently recover acetylene from acetylene mixed gas is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the Invention

[0006] The present invention provides an acetylene mixed gas recovery method, which can efficiently recover acetylene from the acetylene mixed gas and facilitates the recovery and utilization of acetylene.

[0007] The present invention provides an acetylene mixed gas recovery device, which helps to realize the above recovery method.

[0008] The present invention provides a method for recovering acetylene mixed gas, comprising the following steps:

[0009] Utilizing the first absorption solvent to absorb the heavy components of the acetylene mixed gas to obtain a heavy-component-rich mixed gas and a solvent;

[0010] Using a second absorption solvent to perform acetylene absorption treatment on the deheaved mixed gas to obtain an acetylene-rich solvent and a light component;

[0011] The acetylene-rich solvent is subjected to a primary acetylene decomposition treatment to obtain acetylene, a first acetylene-light component mixed gas and a primary solvent component, and the first acetylene-light component mixed gas and the acetylene mixed gas are jointly subjected to the heavy component absorption treatment.

[0012] The recycling method as described above, wherein, further comprises:

[0013] performing a secondary acetylene decomposition treatment on the primary solvent component to obtain an acetylene-heavy component mixed gas, a secondary heavy component, and a first recovered solvent;

[0014] allowing the acetylene-heavy component mixed gas to participate in the primary acetylene decomposition treatment as a stripping gas;

[0015] The first recovery solvent is used as the second absorption solvent in the acetylene absorption process.

[0016] The recycling method as described above, wherein, further comprises:

[0017] performing a three-stage acetylene desorption process on the heavy component-rich solvent to obtain a second acetylene-light component mixed gas and three-stage heavy components;

[0018] The second acetylene-light component mixed gas and the acetylene mixed gas are jointly involved in the heavy component absorption process.

[0019] The recycling method as described above, wherein, further comprises:

[0020] contacting the secondary heavy component with the tertiary heavy component to perform heavy component analysis to obtain a recovered heavy component and a secondary solvent component;

[0021] performing solvent recovery treatment on the secondary solvent to obtain a second recovered solvent and waste material;

[0022] The second recovery solvent is used as the first absorption solvent to participate in the heavy component absorption process.

[0023] The recycling method as described above, wherein, further comprises:

[0024] At least part of the light component is used as stripping gas to participate in the three acetylene treatments, and the remaining light component is subjected to light component separation treatment to obtain a first light component and a second light component.

[0025] The present invention also provides an acetylene mixed gas recovery device for performing any of the aforementioned recovery methods, comprising: a heavy component absorption unit, an acetylene absorption unit, and a primary acetylene desorption unit; the light component outlet of the heavy component absorption unit is connected to the absorption inlet of the acetylene absorption unit, and the acetylene outlet of the acetylene absorption unit is connected to the desorption inlet of the primary acetylene desorption unit;

[0026] The primary acetylene analysis unit further includes an acetylene outlet and an acetylene-light component mixed gas outlet, and the acetylene-light component mixed gas outlet of the primary acetylene analysis unit is connected to the acetylene mixed gas inlet of the heavy component absorption unit.

[0027] The recovery device as described above further includes a secondary acetylene decomposition unit; the primary solvent component outlet of the primary acetylene decomposition unit is connected to the decomposition inlet of the secondary acetylene decomposition unit, the acetylene-heavy component mixed gas outlet of the secondary acetylene decomposition unit is connected to the stripping medium inlet of the primary acetylene decomposition unit, and the recovery solvent outlet of the secondary acetylene decomposition unit is connected to the absorption solvent inlet of the acetylene absorption unit.

[0028] The recovery device as described above, wherein, further comprises a tertiary acetylene analysis unit;

[0029] The heavy component solvent-rich outlet of the heavy component absorption unit is communicated with the decomposition inlet of the tertiary acetylene decomposition unit, and the acetylene-light component mixed gas outlet of the tertiary acetylene decomposition unit is communicated with the acetylene mixed gas inlet of the heavy component absorption unit.

[0030] The recovery device as described above, wherein, further comprises a heavy component analysis unit and a solvent recovery unit;

[0031] The decomposition inlet of the heavy component decomposition unit is respectively connected to the secondary heavy component outlet of the secondary acetylene decomposition unit and the tertiary heavy component outlet of the tertiary acetylene decomposition unit. The recovery heavy component outlet of the heavy component decomposition unit is used to output the recovered heavy component. The recovery solvent outlet of the heavy component decomposition unit is connected to the recovery inlet of the solvent recovery unit. The recovery solvent outlet of the solvent recovery unit is connected to the absorption solvent inlet of the heavy component absorption unit.

[0032] In the recovery device as described above, the light component outlet of the acetylene absorption unit is communicated with the stripping medium inlet of the tertiary acetylene analysis unit and the light component inlet of the light component separation unit respectively.

[0033] The acetylene gas mixture recovery method provided by the present invention sequentially separates heavy components and light components from the acetylene gas mixture by subjecting the acetylene gas mixture to heavy component absorption treatment and acetylene absorption treatment, thereby obtaining an acetylene-rich solvent. Finally, the acetylene-rich solvent is subjected to a further acetylene desorption treatment to dissociate the acetylene and complete the acetylene separation. The recovery method of the present invention not only enables acetylene recovery, but also achieves a purity of over 99%. The recovered acetylene can be used as cutting fuel gas, a raw material for silicon-carbon materials, and other related processes, thereby avoiding waste of acetylene resources in the acetylene gas mixture. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and, together with the description, serve to explain the principles of the invention.

[0035] Figure 1 1 is a process flow chart of an embodiment of the present invention. DETAILED DESCRIPTION

[0036] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0037] As mentioned above, acetylene mixed gas generally contains a high acetylene content. In order to avoid the waste of acetylene resources caused by too low acetylene recovery rate in acetylene mixed gas, the inventors proposed the acetylene mixed gas recovery method of the present invention with the purpose of recovering high-purity acetylene at a high recovery rate.

[0038] A first aspect of the present invention provides a method for recovering an acetylene gas mixture, comprising the following steps: performing a heavy component absorption treatment on the acetylene gas mixture using a first absorption solvent to obtain a heavy component-depleted mixed gas and a heavy component-rich solvent; performing an acetylene absorption treatment on the heavy component-depleted mixed gas using a second absorption solvent to obtain an acetylene-rich solvent and a light component; performing a primary acetylene desorption treatment on the acetylene-rich solvent to obtain acetylene, a first acetylene-light component mixed gas, and a primary solvent component, and allowing the first acetylene-light component mixed gas and the acetylene gas mixture to participate in the heavy component absorption treatment together.

[0039] The recovery method of the present invention is applicable to any acetylene-containing gas mixture, such as the tail gas from acetylene production using methane-rich gas or the tail gas from silicon-carbon anode material production. Generally, acetylene gas mixtures contain not only acetylene but also other components, such as light components like hydrogen, nitrogen, methane, and ethane, as well as small amounts of heavy components like higher alkynes and tar.

[0040] In the recovery method of the present invention, the acetylene gas mixture is first subjected to heavy component absorption treatment using a first absorption solvent. Specifically, the first absorption solvent is used to dissolve the heavy components in the acetylene gas mixture. Through the selective dissolution of the heavy components by the first absorption solvent, a heavy-depleted mixed gas and a heavy-component-rich solvent are obtained. The heavy-component-rich solvent contains a large amount of heavy components and relatively small amounts of solutes such as acetylene and light components. The heavy-depleted mixed gas is the remaining portion of the acetylene gas mixture after the aforementioned solutes have been removed, and primarily contains a large amount of acetylene and light components.

[0041] Subsequently, the depleted mixed gas is subjected to acetylene absorption treatment using a second absorption solvent. During the acetylene absorption treatment, the second absorption solvent can dissolve most of the acetylene in the depleted mixed gas to obtain an acetylene-rich solvent, while the remaining undissolved portion is the light component.

[0042] Finally, the acetylene-rich solvent undergoes a primary acetylene desorption process to produce acetylene, a first acetylene-light component mixed gas, and a primary solvent component. Specifically, the primary acetylene desorption process can be achieved through decompression. Through the pressure change, the solute and solvent in the acetylene-rich solvent flash and separate. Because the acetylene and light components in the solute have different boiling points, separated acetylene, a first acetylene-light component mixed gas, and a primary solvent component can be obtained. The purity of the acetylene can reach up to 99%. The light components in the first acetylene-light component mixed gas are the main components. The primary solvent component, in addition to the solvent, also includes a small amount of acetylene and a small amount of heavy components that were not absorbed during the heavy component absorption process.

[0043] Since the solubility and boiling point of the light component and acetylene are closer, in order to further improve the acetylene recovery rate, the present invention also returns the first acetylene-light component mixed gas to participate in the heavy component absorption treatment together with the acetylene mixed gas, and through cyclic enrichment, it is expected to maximize the recovery of acetylene in the acetylene mixed gas.

[0044] The present invention does not limit the selection of the first absorption solvent and the second absorption solvent, as long as the aforementioned objectives can be achieved. In one embodiment, the first absorption solvent and the second absorption solvent can be at least one of N-methylpyrrolidone (NMP), N,N-dimethylformamide (DMF), kerosene, diesel, acetone, and the like.

[0045] Furthermore, in order to improve the efficiency of the heavy component absorption treatment, the acetylene absorption treatment and the primary acetylene decomposition treatment, the heavy component absorption treatment and the acetylene absorption treatment may be carried out at a pressure of 0.5 to 1.2 MPaA, for example, 0.6 MPaA, 0.7 MPaA, 0.8 MPaA, 0.9 MPaA, 1.0 MPaA, and 1.1 MPaA, and the primary acetylene decomposition treatment may be carried out at a pressure of 0.10 to 0.15 MPaA, for example, 0.11 MPaA, 0.12 MPaA, 0.13 MPa, and 0.14 MPaA.

[0046] The recovery method of the present invention sequentially performs heavy component absorption, acetylene absorption, and primary acetylene desorption on the acetylene mixture to separate acetylene from heavy and light components. This not only allows for the recovery of acetylene but also improves its purity. The recovered acetylene can be further processed in other processes, such as coupling with processes that use acetylene as a raw material, such as silicon-carbon anode materials, saving raw material costs and avoiding waste of acetylene resources.

[0047] Furthermore, to further improve the acetylene recovery rate, the acetylene in the primary solvent component can be recovered. In one embodiment, the recovery method of the present invention further includes subjecting the primary solvent component to a secondary acetylene desorption process to produce an acetylene-heavy component mixed gas, a secondary heavy component, and a recovered solvent; using the acetylene-heavy component mixed gas as a stripping gas in the primary acetylene desorption process; and using the recovered solvent as a secondary absorption solvent in the acetylene absorption process.

[0048] Specifically, the secondary acetylene desorption process is accomplished by subjecting the primary solvent component to a temperature-and-pressure reduction treatment, resulting in a vacuum thermal separation of the solutes, including acetylene and heavy components, from the solvent. After the solutes in the primary solvent component are separated under vacuum heating, the remaining solvent, referred to as the recovered solvent, is separated. Due to their boiling point differences, the acetylene and heavy components in the solute also separate, yielding an acetylene-heavy component mixed gas and a secondary heavy component. The heavy components in the secondary heavy component comprise approximately 2% by weight, while the acetylene content of the acetylene-heavy component mixed gas exceeds 50% by weight.

[0049] Since the acetylene content in the acetylene-heavy component mixed gas is relatively high, it is returned as stripping gas to participate in the primary acetylene desorption treatment, so that the acetylene therein is enriched and recovered in the primary acetylene desorption treatment, and the obtained recovery solvent can be used as the second absorption solvent to continue to participate in the acetylene absorption treatment, thereby reducing the solvent cost of the recovery method of the present invention.

[0050] In order to further improve the acetylene recovery rate of the recovery method of the present invention, when the acetylene-heavy component is returned to participate in the first acetylene desorption treatment, the acetylene-heavy component and the acetylene-rich solvent can be brought into reverse contact, so that the acetylene in the acetylene-heavy component can be recovered to a greater extent.

[0051] In a specific embodiment, the pressure of the secondary acetylene desorption treatment is 0.01-0.05 MPaA, for example, 0.02 MPaA, 0.03 MPaA, or 0.04 MPaA.

[0052] As previously mentioned, the heavy component-rich solvent includes a large amount of heavy components and relatively small amounts of acetylene and light components. Therefore, the present invention further performs a tertiary acetylene desorption process on the component-rich solvent. Specifically, the tertiary acetylene desorption process separates the acetylene, light components, and heavy components by reducing the pressure, thereby producing a second acetylene-light component mixed gas and a tertiary heavy component. The second acetylene-light component mixed gas contains no less than 65% by mass of acetylene, and the tertiary heavy component contains no less than 3% by mass of heavy components.

[0053] The second acetylene-light component mixture is returned to participate in the heavy component absorption process together with the acetylene mixture, thereby enriching and separating the acetylene in the second acetylene-light component mixture and improving the acetylene recovery rate. For example, in the three-stage acetylene desorption process, the desorption pressure can be 0.10-0.15 MPaA, for example, 0.12 MPaA, 0.13 MPaA, or 0.14 MPaA.

[0054] In the recovery method of the present invention, a secondary heavy component is obtained by decomposition in the secondary acetylene decomposition process, and a tertiary heavy component is obtained in the tertiary acetylene decomposition process. The tertiary heavy component includes the heavy components dissolved in the first absorption solvent during the heavy component absorption process, and the secondary heavy component includes the heavy components that were not dissolved in the first absorption solvent during the heavy component absorption process and entered the second absorption solvent. Therefore, the secondary and tertiary heavy components not only contain a large amount of heavy components in the enriched acetylene gas mixture but also include solvent. To recover the solvent, the recovery method of the present invention further involves contacting the secondary and tertiary heavy components to perform a heavy component decomposition process to obtain recovered heavy components and a secondary solvent component; performing a solvent recovery process on the secondary solvent to obtain a second recovered solvent and waste; and allowing the second recovered solvent to participate in the heavy component absorption process as the first absorption solvent.

[0055] Specifically, in the heavy component analysis process, the secondary heavy component and the tertiary heavy component come into contact with each other, and the heavy components therein are analyzed and enriched from the solvent to obtain recovered heavy components and secondary solvent components, respectively. Among them, the recovered heavy components are the majority of the heavy components in the acetylene mixed gas, which can be separated and recovered again as needed to obtain the required components, or directly incinerated; and the secondary solvent component may also include some high-boiling tar and other waste materials in addition to the solvent. The waste materials can be further separated from the solvent by performing solvent recovery treatment on the secondary solvent component to obtain a second recovered solvent. By returning the second recovered solvent as the first absorption solvent to participate in the heavy component absorption process, the heavy components in the acetylene mixed gas are recovered, thereby realizing the recycling of the solvent and effectively reducing the solvent input cost of the recovery method of the present invention.

[0056] During the specific recovery process, to improve the heavy component resolution, the secondary heavy component and the tertiary heavy component can be brought into countercurrent contact, and the pressure for the heavy component resolution can be controlled to be between 0.01 and 0.05 MPaA, for example, 0.02 MPaA, 0.03 MPaA, or 0.04 MPaA. Furthermore, solvent recovery can be achieved by heating and evaporation, whereby the solvent in the secondary solvent component is heated to escape in the gaseous phase, yielding a gaseous second recovered solvent. Subsequently, the gaseous second recovered solvent is cooled to a liquid phase by condensation, where it can then participate in the heavy component absorption process of the acetylene gas mixture.

[0057] The light fraction obtained during the acetylene absorption process can also be used as a stripping gas in the tertiary acetylene desorption process. By contacting the light fraction with a heavy fraction-rich solvent, the majority of the acetylene in the heavy fraction-rich solvent is desorbed to form a secondary acetylene-light fraction mixed gas, thereby improving acetylene recovery.

[0058] It should be noted that the amount of light components participating in the tertiary acetylene desorption process can be controlled as needed. For example, to maximize acetylene recovery in the acetylene mixture, all light components can be subjected to the tertiary acetylene desorption process. If the acetylene mixture also contains other resource-based light components, a portion of the light components can be subjected to the tertiary acetylene desorption process, and the remaining light components can be subjected to light component separation to obtain a first light component and a second light component. For example, if the light components include hydrogen, the remaining light components can be subjected to pressure swing adsorption to separate the hydrogen from the other light components.

[0059] The recovery method of the present invention separates acetylene from heavy components and light components in the acetylene mixed gas by orderly processing the acetylene mixed gas, so that the acetylene recovery rate can reach more than 90%, thereby greatly avoiding the waste of acetylene resources.

[0060] A second aspect of the present invention provides an acetylene mixed gas recovery device for executing the recovery method of the first aspect.

[0061] like Figure 1 As shown, the recovery device of the present invention includes a heavy component absorption unit 1, an acetylene absorption unit 2, and a primary acetylene decomposition unit 3; the light component outlet of the heavy component absorption unit 1 is connected to the absorption inlet of the acetylene absorption unit 2, and the acetylene outlet of the acetylene absorption unit 2 is connected to the decomposition inlet of the primary acetylene decomposition unit 3; wherein, the primary acetylene decomposition unit 3 further includes an acetylene outlet and an acetylene-light component mixed gas outlet, and the acetylene-light component mixed gas outlet of the primary acetylene decomposition unit 3 is connected to the acetylene mixed gas inlet of the heavy component absorption unit 1.

[0062] The heavy component absorption unit 1 is used to realize heavy component absorption treatment, the acetylene absorption unit 2 is used to realize acetylene absorption treatment, and the primary acetylene analysis unit 3 is used to realize primary acetylene analysis treatment.

[0063] After entering heavy component absorption unit 1 through the acetylene mixed gas inlet, acetylene mixed gas 1A undergoes heavy component absorption treatment with the first absorption solvent that enters heavy component absorption unit 1 through the absorption solvent inlet of heavy component absorption unit 1, producing heavy component-depleted mixed gas 1B and heavy component-enriched solvent 1C. After exiting through the light component outlet at the top of heavy component absorption unit 1, heavy component-depleted mixed gas 1B enters acetylene absorption unit 2 through the absorption inlet of acetylene absorption unit 2.

[0064] The depleted mixed gas 1B undergoes acetylene absorption with the second absorption solvent introduced into the acetylene absorption unit 2 through its absorption solvent inlet, thereby producing an acetylene-rich solvent 2A and a light component 2B. The acetylene-rich solvent is output through the acetylene outlet at the bottom of the acetylene absorption unit 2 and enters the primary acetylene desorption unit 3 through its desorption inlet for primary desorption.

[0065] In the primary acetylene decomposition unit 3, the decomposed acetylene 3A reaches the highest concentration in the middle of the primary acetylene decomposition unit 3, and can therefore be output through the acetylene outlet in the middle of the primary acetylene decomposition unit 3, while the first acetylene-light component mixed gas 3B is output through the acetylene-light component mixed gas outlet at the top of the primary acetylene decomposition unit 3, and returns to the heavy component absorption unit 1 through the acetylene mixed gas inlet of the heavy component absorption unit 1 to participate in the heavy component absorption process.

[0066] The recovery device of the present invention helps to realize the recovery of acetylene in the acetylene mixed gas, thereby avoiding the waste of acetylene mixed gas resources.

[0067] The present invention does not limit the specific forms of the heavy component absorption unit 1, the acetylene absorption unit 2, and the primary acetylene desorption unit 3. For example, the heavy component absorption unit 1 and the acetylene absorption unit 2 may be absorption towers, and the primary acetylene desorption unit 3 may be a desorption tower.

[0068] Furthermore, the recovery device of the present invention also includes a secondary acetylene decomposition unit 4; the primary solvent component outlet of the primary acetylene decomposition unit 3 is connected to the decomposition inlet of the secondary acetylene decomposition unit 4, the acetylene-heavy component mixed gas outlet of the secondary acetylene decomposition unit 4 is connected to the stripping medium inlet of the primary acetylene decomposition unit 3, and the recovery solvent outlet of the secondary acetylene decomposition unit 4 is connected to the absorption solvent inlet of the acetylene absorption unit 2.

[0069] The secondary acetylene decomposition unit 4 is used to implement the aforementioned secondary acetylene decomposition process, and may be, for example, a decomposition tower.

[0070] The solvent outlet at the bottom of the primary acetylene desorption unit 3 is used to output a primary solvent component 3C. This primary solvent component 3C enters the secondary acetylene desorption unit 4 through the desorption inlet, where it undergoes secondary acetylene desorption, producing an acetylene-heavy component mixed gas 4A, a secondary heavy component 4B, and a first recovered solvent 4C. The acetylene-heavy component mixed gas 4A is output through the acetylene-heavy component mixed gas outlet at the top and enters the primary acetylene desorption unit 3 through the stripping medium inlet of the primary acetylene desorption unit 3 to improve the desorption efficiency of the primary acetylene desorption process. The secondary heavy component 4B is enriched in the middle of the secondary acetylene desorption unit 4 and then output through the heavy component outlet in the middle of the secondary acetylene desorption unit 4. The first recovered solvent 4C is enriched at the bottom of the secondary acetylene desorption unit 4, output through the bottom recovered solvent outlet, and then enters the acetylene absorption unit 2 through the absorption solvent inlet of the acetylene absorption unit 2 as the second absorption solvent to participate in the acetylene absorption process.

[0071] In order to ensure the normal progress of the secondary acetylene decomposition process, the device of the present invention further comprises an evaporator 4 a of the secondary acetylene decomposition unit. The evaporator 4 a is in communication with the secondary acetylene decomposition unit 4 and is used to provide decomposition heat for the secondary acetylene decomposition unit 4 .

[0072] Furthermore, a first condenser 4 b is provided between the recovery solvent outlet of the secondary acetylene desorption unit 4 and the acetylene absorption unit 2 , for condensing and cooling the first recovery solvent 4C before it enters the acetylene absorption unit 2 .

[0073] In a specific embodiment, the recovery device of the present invention further includes a tertiary acetylene decomposition unit 5; the heavy component-rich solvent outlet of the heavy component absorption unit 1 is connected to the decomposition inlet of the tertiary acetylene decomposition unit 5, and the acetylene-light component mixed gas outlet of the tertiary acetylene decomposition unit 5 is connected to the acetylene mixed gas inlet of the heavy component absorption unit 1.

[0074] Specifically, the tertiary acetylene desorption unit 5 is used to implement the aforementioned tertiary acetylene desorption process and, for example, can be a desorption tower. After being output from the tertiary acetylene desorption unit 1 through the tertiary acetylene desorption unit 5 outlet, the heavy component-rich solvent 1C enters the tertiary acetylene desorption unit 5 through the desorption inlet of the tertiary acetylene desorption unit 5 for tertiary acetylene desorption, thereby producing a second acetylene-light component mixed gas 5A and a tertiary heavy component 5B. The second acetylene-light component mixed gas 5A, after being output from the acetylene-light component mixed gas outlet of the tertiary acetylene desorption unit 5, enters the heavy component absorption unit 1 through the acetylene mixed gas inlet, and participates in the heavy component absorption process together with the acetylene mixed gas 1A.

[0075] The recovery device of the present invention also includes a heavy component analysis unit 6 and a solvent recovery unit 7; the analysis inlet of the heavy component analysis unit 6 is respectively connected to the secondary heavy component outlet of the secondary acetylene analysis unit 4 and the tertiary heavy component outlet of the tertiary acetylene analysis unit 5, the recovered heavy component outlet of the heavy component analysis unit 6 is used to output the recovered heavy component 6A, the recovered solvent outlet of the heavy component analysis unit 6 is connected to the recovery inlet of the solvent recovery unit 7, and the recovered solvent outlet of the solvent recovery unit 7 is connected to the absorption solvent inlet of the heavy component absorption unit 1.

[0076] The heavy component analysis unit 6 is used to perform the aforementioned heavy component analysis process, and the solvent recovery unit 7 is used to perform the aforementioned solvent recovery process. For example, the heavy component analysis unit 6 can be a analysis tower, and the solvent recovery unit 7 can be an evaporator.

[0077] After the secondary heavy component 4B is output through the secondary heavy component outlet of the secondary acetylene decomposition unit 4, it enters the heavy component decomposition unit 6 through the decomposition inlet of the heavy component decomposition unit 6. Similarly, after the tertiary heavy component 5B is output through the tertiary heavy component outlet of the tertiary acetylene decomposition unit 5, it enters the heavy component decomposition unit 5 through the decomposition inlet of the heavy component decomposition unit 5. Inside the heavy component decomposition unit 5, the secondary heavy component 4B and the tertiary heavy component 5B undergo heavy component decomposition processing to obtain a recovered heavy component 6A and a secondary solvent component 6B. The recovered heavy component 6A is output through the recovered heavy component outlet of the heavy component decomposition unit 6, and the secondary solvent component 6B enters the solvent recovery unit 7 through the recovered solvent outlet of the heavy component decomposition unit 6 and the recovery inlet of the solvent recovery unit 7, and undergoes solvent recovery processing in the solvent recovery unit 7. Subsequently, the second recovered solvent 7A in the solvent recovery unit 7 enters the heavy component absorption unit 1 through the recovered solvent outlet of the solvent recovery unit 7 and the absorption solvent inlet of the heavy component absorption unit 1 as the first absorption solvent to participate in the heavy component absorption processing. The bottom waste outlet of the solvent recovery unit 7 is used to output the waste 7B separated from the secondary solvent component 6B.

[0078] Furthermore, a second condenser 7a is provided between the recovery solvent outlet of the second recovery solvent 7A through the solvent recovery unit 7 and the heavy component absorption unit 1 for condensing and cooling the second recovery solvent 7A before the second recovery solvent 7A enters the heavy component absorption unit 1 .

[0079] Furthermore, to maximize the recovery of acetylene from the light fraction 2B output by the acetylene absorption unit 2, the recovery apparatus of the present invention connects the light fraction outlet of the acetylene absorption unit 2 to the stripping medium inlet of the tertiary acetylene desorption unit 5 and the light fraction inlet of the light fraction separation unit, respectively. This arrangement allows the light fraction 2B to enter the tertiary acetylene desorption unit 5 and the light fraction separation unit (not shown), respectively.

[0080] In the tertiary acetylene desorption unit 5, the light component 2B contacts the heavy component-rich solvent 1C, further ensuring that the majority of the acetylene in the heavy component-rich solvent 1C is desorbed to form a second acetylene-light component mixed gas 5A, thereby improving the acetylene recovery rate. The light component separation unit of the present invention is used to separate the light component 2B to obtain a first light component and a second light component. For example, when the light component includes hydrogen, light component separation can be achieved by pressure swing adsorption of the light component (in this case, the light component separation unit is a pressure swing adsorber), thereby separating the hydrogen (the first light component) from the other light component (the second light component).

[0081] Specifically, a flow controller can be set between the light component outlet of the acetylene absorption unit 2 and the stripping medium inlet of the tertiary acetylene decomposition unit 5, as well as the light component inlet of the light component separation unit. By adjusting the flow controller, the proportion of the light component 2B entering the tertiary acetylene decomposition unit 5 and the light component separation unit can be flexibly adjusted.

[0082] The acetylene mixed gas recovery method and recovery device provided by the present invention can not only realize the recovery of acetylene in the acetylene mixed gas, but also achieve a purity of the recovered acetylene of more than 99%. The recovered acetylene can be used as a raw material in the corresponding process flow, thereby greatly avoiding the waste of acetylene resources.

[0083] Example

[0084] use Figure 1The device shown recovers acetylene tail gas. Specifically, the volume percentage of the acetylene tail gas is as follows: nitrogen 73.90%, acetylene 11.13%, hydrogen 6.78%, methane 5.08%, ethane 1.30%, ethylene 1.27%, propylene 0.23%, propane 0.16%, benzene 0.058%, butene 0.051%, butadiene 0.034%, butane 34ppm, propyne 19ppm, and butyne 17ppm. NMP is used as the absorption solvent. During the recovery process, NMP is used as the primary and secondary absorption solvents. The operating pressures and temperatures of the various towers in the device are shown in Table 1.

[0085] Table 1

[0086]

[0087] After testing, the purity of the acetylene finally recovered in this embodiment was 99.1%, and the recovery rate was 92.5%.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for recovering acetylene mixed gas, characterized in that: The following steps are involved: Utilizing the first absorption solvent to absorb the heavy components of the acetylene mixed gas to obtain a heavy-component-rich mixed gas and a solvent; Using a second absorption solvent to perform acetylene absorption treatment on the deheaved mixed gas to obtain an acetylene-rich solvent and a light component; The acetylene-rich solvent is subjected to a primary acetylene decomposition treatment to obtain acetylene, a first acetylene-light component mixed gas and a primary solvent component, and the first acetylene-light component mixed gas and the acetylene mixed gas are jointly subjected to the heavy component absorption treatment.

2. The recycling method according to claim 1, wherein: Also includes: performing a secondary acetylene decomposition treatment on the primary solvent component to obtain an acetylene-heavy component mixed gas, a secondary heavy component, and a first recovered solvent; allowing the acetylene-heavy component mixed gas to participate in the primary acetylene decomposition treatment as a stripping gas; The first recovery solvent is used as the second absorption solvent in the acetylene absorption process.

3. The recycling method according to claim 2, characterized in that Also includes: performing a three-stage acetylene desorption process on the heavy component-rich solvent to obtain a second acetylene-light component mixed gas and three-stage heavy components; The second acetylene-light component mixed gas and the acetylene mixed gas are jointly involved in the heavy component absorption process.

4. The recycling method according to claim 3, characterized in that Also includes: contacting the secondary heavy component with the tertiary heavy component to perform heavy component analysis to obtain a recovered heavy component and a secondary solvent component; performing solvent recovery treatment on the secondary solvent to obtain a second recovered solvent and waste material; The second recovery solvent is used as the first absorption solvent to participate in the heavy component absorption process.

5. The recycling method according to claim 3 or 4, characterized in that: Also includes: At least part of the light component is used as stripping gas to participate in the three acetylene treatments, and the remaining light component is subjected to light component separation treatment to obtain a first light component and a second light component.

6. An acetylene mixed gas recovery device, characterized in that: Used to perform the recovery method according to any one of claims 1 to 5, comprising: a heavy component absorption unit, an acetylene absorption unit, and a primary acetylene desorption unit; the light component outlet of the heavy component absorption unit is connected to the absorption inlet of the acetylene absorption unit, and the acetylene outlet of the acetylene absorption unit is connected to the desorption inlet of the primary acetylene desorption unit; The primary acetylene analysis unit further includes an acetylene outlet and an acetylene-light component mixed gas outlet, and the acetylene-light component mixed gas outlet of the primary acetylene analysis unit is connected to the acetylene mixed gas inlet of the heavy component absorption unit.

7. The recovery device according to claim 6, characterized in that It also includes a secondary acetylene decomposition unit; the primary solvent component outlet of the primary acetylene decomposition unit is connected to the decomposition inlet of the secondary acetylene decomposition unit, the acetylene-heavy component mixed gas outlet of the secondary acetylene decomposition unit is connected to the stripping medium inlet of the primary acetylene decomposition unit, and the recovery solvent outlet of the secondary acetylene decomposition unit is connected to the absorption solvent inlet of the acetylene absorption unit.

8. The recovery device according to claim 7, characterized in that: Also included is a tertiary acetylene analysis unit; The heavy component solvent-rich outlet of the heavy component absorption unit is communicated with the decomposition inlet of the tertiary acetylene decomposition unit, and the acetylene-light component mixed gas outlet of the tertiary acetylene decomposition unit is communicated with the acetylene mixed gas inlet of the heavy component absorption unit.

9. The recovery device according to claim 8, characterized in that: It also includes a heavy component analysis unit and a solvent recovery unit; The decomposition inlet of the heavy component decomposition unit is respectively connected to the secondary heavy component outlet of the secondary acetylene decomposition unit and the tertiary heavy component outlet of the tertiary acetylene decomposition unit. The recovery heavy component outlet of the heavy component decomposition unit is used to output the recovered heavy component. The recovery solvent outlet of the heavy component decomposition unit is connected to the recovery inlet of the solvent recovery unit. The recovery solvent outlet of the solvent recovery unit is connected to the absorption solvent inlet of the heavy component absorption unit.

10. The recovery device according to claim 8 or 9, characterized in that: The light component outlet of the acetylene absorption unit is communicated with the stripping medium inlet of the tertiary acetylene analysis unit and the light component inlet of the light component separation unit respectively.

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