A mixed gas compression device for preparing dimethyl carbonate by urea alcoholysis

Abstract

The utility model relates to carbonic acid dimethyl ester production equipment technical field, in view of the existing equipment linkage between the poor, space and energy waste rate high problem existing in the compression treatment of the mixed gas produced by the urea alcoholysis method preparation carbonic acid dimethyl ester, specifically discloses a kind of mixed gas compression device for urea alcoholysis method preparation carbonic acid dimethyl ester, including the pretreatment unit and compression unit of head-tail sequential intercommunication, the feed end of the pretreatment unit is communicated with the reactor discharge end of preparation carbonic acid dimethyl ester;The discharge end of the compression unit is respectively configured with interstage cooler and aftercooler, the discharge end of the interstage cooler is configured with hot reflux pipe, the hot reflux pipe is communicated with the pretreatment unit. Through the joint use between each equipment, not only can more efficient controllable mixed gas be pretreated and recompressed, but also can utilize different energy produced by different links to a greater extent, effectively improve work efficiency and processing effect.

Description

Technical Field

[0001] This utility model relates to the technical field of dimethyl carbonate production equipment, and more specifically, to a mixed gas compression device for preparing dimethyl carbonate by urea alcoholysis. Background Technology

[0002] The urea alcoholysis method for preparing dimethyl carbonate refers to a process route that uses urea and methanol as raw materials to produce dimethyl carbonate under the action of a catalyst. It is widely used due to its advantages such as non-toxic and widely available raw materials and high economic efficiency. The urea alcoholysis method for preparing dimethyl carbonate mainly involves two steps: The first step is the reaction of urea with methanol to produce methyl carbamate. The reaction process is as follows: (NH2)2CO + CH3OH → NH2COOCH3+ NH3; The second step is the further reaction of methyl methcarbamate with methanol to produce dimethyl carbonate. The reaction process is as follows: NH2COOCH3+ CH3OH → (CH3O)2CO + NH3; As can be seen from the above reaction process, the preparation of dimethyl carbonate via urea alcoholysis releases a large amount of mixed gas containing ammonia and other components. Specifically, the mixed gas generated in the preparation of dimethyl carbonate via urea alcoholysis mainly includes ammonia, methanol vapor, and other trace components. Methanol vapor is usually formed due to the vaporization of excess raw materials. Although ammonia and methanol vapor have significantly different boiling points, the wet ammonia in the mixed gas is corrosive, and methanol is flammable. Therefore, the mixed gas usually needs to be compressed to improve methanol condensation efficiency and facilitate separation. The effectiveness of compression is a key factor in achieving efficient ammonia removal and methanol recovery.

[0003] Currently, most methods involve directly transporting the reacted gas mixture to compression equipment via pipelines for further processing, and then distributing it to subsequent stages through pipelines. For example, patent CN206886993U provides an energy-saving and consumption-reducing device for dimethyl carbonate plants, which uses a distillation heat pump to compress the dimethyl carbonate and methanol mixture at the top of the methanol distillation column. However, existing compression devices like these suffer from poor continuity between equipment and involve significant manpower and material consumption in actual production. Utility Model Content

[0004] The purpose of this invention is to solve the problems of poor equipment coordination and high space and energy waste in the existing compression treatment of the mixed gas produced by urea alcoholysis to dimethyl carbonate. This application provides a mixed gas compression device for urea alcoholysis to dimethyl carbonate production. By using various devices in combination, it is possible to not only pre-treat and re-compress the mixed gas more efficiently and controllably, but also to make greater use of the different energy sources generated in different stages, effectively improving work efficiency and processing effect.

[0005] This utility model is achieved through the following technical solution: This invention provides a mixed gas compression device for the preparation of dimethyl carbonate by urea alcoholysis, comprising a pretreatment unit and a compression unit connected sequentially. The feed end of the pretreatment unit is connected to the discharge end of the reactor for preparing dimethyl carbonate. The discharge end of the compression unit is respectively equipped with an interstage cooler and an aftercooler. The discharge end of the interstage cooler is equipped with a hot reflux pipe, which is connected to the pretreatment unit.

[0006] Preferably, the pretreatment unit includes a demister, a filter, and a heater connected in sequence from end to end. The feed end of the demister is connected to the discharge end of the reactor via a pipeline, and the discharge end of the heater is connected to the compression unit.

[0007] Preferably, the pretreatment unit is further equipped with a slag discharge pipe, which includes a solid particle pipe and a small particle pipe. The solid particle pipe passes through the bottom of the demister, and the small particle pipe passes through the bottom of the filter.

[0008] Preferably, the outlet end of the heat reflux pipe is connected to the inlet end of the heater.

[0009] Preferably, the discharge end of the interstage cooler is further provided with a circulation pipe, which is connected to the feed end of the compression unit.

[0010] Preferably, the compression unit includes a plurality of gas-mixing compressors connected in series, and each gas-mixing compressor is equipped with an interstage cooling pipe at its discharge end, the interstage cooling pipe being connected to the feed end of the interstage cooler.

[0011] Preferably, an vent pipe is provided on the top of the gas-mixing compressor, and a vacuum pump is provided at one end of the vent pipe near the gas-mixing compressor.

[0012] Preferably, the discharge end of the aftercooler is provided with a circulating feed pipe, and the feed end of the circulating feed pipe away from the aftercooler is connected to the feed end at the bottom of the reactor.

[0013] The technical solution of this utility model has the following beneficial effects: This invention relates to a mixed gas compression device for the preparation of dimethyl carbonate via urea alcoholysis. By combining various devices, it not only enables more efficient and controllable pretreatment and recompression of the mixed gas, but also makes greater use of the different energy sources generated in different stages, achieving integrated and modular production technology, reducing energy consumption, and effectively improving work efficiency and the processing effects of mixed gas compression, separation, and reuse. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the mixed gas compression device used in the urea alcoholysis method for preparing dimethyl carbonate in Example 1; Figure 2 This is a system schematic diagram of the preprocessing unit in Example 1; Figure 3 This is a system schematic diagram of the compression unit in Example 1.

[0015] Reference numerals: 1-reactor, 2-pretreatment unit, 21-demister, 22-filter, 23-heater, 24-slag discharge pipe, 241-solid particle pipe, 242-small particle pipe, 3-mixed gas compressor, 31-vent pipe, 32-vacuum pump, 41-interstage cooler, 42-aftercooler, 43-heat reflux pipe, 44-cooling circulation pipe, 5-circulating feed pipe. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions of this utility model will be clearly and completely described below. Where specific conditions are not specified in the embodiments, they are performed according to conventional conditions or conditions recommended by the manufacturer; where the manufacturers of instruments, equipment, reagents, or raw materials are not specified, they are all conventional products that can be purchased commercially. The following are specific embodiments in conjunction with the accompanying drawings.

[0017] like Figures 1 to 3 As shown, this embodiment provides a mixed gas compression device for the preparation of dimethyl carbonate by urea alcoholysis, including a pretreatment unit 2 and a compression unit connected in sequence. The feed end of the pretreatment unit 2 is connected to the discharge end of the reactor 1 for preparing dimethyl carbonate. The pretreatment unit 2 includes a demister 21, a filter 22 and a heater 23 connected in sequence. The feed end of the demister 21 is connected to the discharge end of the reactor 1 through a pipeline, and the discharge end of the heater 23 is connected to the compression unit. The pretreatment unit 2 is also equipped with a slag discharge pipe 24, which includes a solid particle pipe 241 and a small particle pipe 242. The solid particle pipe 241 passes through the bottom of the demister 21, and the small particle pipe 242 passes through the bottom of the filter 22.

[0018] In this embodiment, the compression unit includes two gas-mixing compressors 3 connected in series. The discharge end of the compression unit is equipped with an interstage cooler 41 and an aftercooler 42, and the discharge end of each gas-mixing compressor 3 is equipped with an interstage cooling pipe. The interstage cooling pipe is connected to the feed end of the interstage cooler 41. The discharge end of the interstage cooler 41 is equipped with a heat reflux pipe 43, and the discharge end of the heat reflux pipe 43 is connected to the feed end of the heater 23. The discharge end of the interstage cooler 41 is also equipped with a cooling circulation pipe 44, and the cooling circulation pipe 44 is connected to the feed end of the compression unit.

[0019] In this embodiment, an exhaust pipe 31 is installed on the top of the gas-mixing compressor 3, and a vacuum pump 32 is installed at the end of the exhaust pipe 31 near the gas-mixing compressor 3. By drawing negative pressure and using the gas-mixing compressor 3, the workload of the compression equipment itself can be reduced, and the working pressure of each component can be distributed and optimized.

[0020] In this embodiment, the discharge end of the aftercooler 42 is equipped with a circulating feed pipe 5. The feed end of the circulating feed pipe 5, which is away from the aftercooler 42, is connected to the feed end at the bottom of the reactor 1. After the above treatment, the cooled and recovered methanol raw material can be obtained and transported back to the reactor 1 through the pipeline for further reaction. This can reduce raw material waste and avoid safety risks caused by the vaporization of methanol.

[0021] By using various devices in combination, it is possible to pre-treat and re-compress the gas mixture more efficiently and controllably, and to make greater use of the different energy sources generated in different stages. This enables integrated and modular production technology, reduces energy consumption, and effectively improves work efficiency and the processing effects of gas mixture compression, separation, and reuse.

[0022] The above are merely preferred embodiments of this utility model and are not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A mixed gas compression apparatus for preparing dimethyl carbonate by urea alcoholysis, characterized in that, It includes a pretreatment unit and a compression unit connected in sequence from end to end, wherein the feed end of the pretreatment unit is connected to the discharge end of the reactor (1) for preparing dimethyl carbonate. The discharge end of the compression unit is equipped with an interstage cooler (41) and an aftercooler (42), and the discharge end of the interstage cooler (41) is equipped with a hot reflux pipe (43), which is connected to the pretreatment unit.

2. The mixed gas compression apparatus for preparing dimethyl carbonate by urea alcoholysis according to claim 1, characterized in that, The pretreatment unit includes a demister (21), a filter (22), and a heater (23) connected in sequence. The feed end of the demister (21) is connected to the discharge end of the reactor (1) through a pipeline, and the discharge end of the heater (23) is connected to the compression unit.

3. The mixed gas compression apparatus for preparing dimethyl carbonate by urea alcoholysis according to claim 2, characterized in that, The pretreatment unit is also equipped with a slag discharge pipe (24), which includes a solid particle pipe (241) and a small particle pipe (242). The solid particle pipe (241) is installed at the bottom of the demister (21), and the small particle pipe (242) is installed at the bottom of the filter (22).

4. The mixed gas compression apparatus for preparing dimethyl carbonate by urea alcoholysis according to claim 2, characterized in that, The outlet end of the heat reflux pipe (43) is connected to the inlet end of the heater (23).

5. The mixed gas compression apparatus for preparing dimethyl carbonate by urea alcoholysis according to claim 2, characterized in that, The discharge end of the interstage cooler (41) is also equipped with a cooling circulation pipe (44), which is connected to the feed end of the compression unit.

6. The mixed gas compression apparatus for the preparation of dimethyl carbonate by urea alcoholysis according to any one of claims 1 to 5, characterized in that, The compression unit includes multiple gas-mixing compressors (3) connected in series, and each gas-mixing compressor (3) is equipped with an interstage cooling pipe at its discharge end, which is connected to the feed end of the interstage cooler (41).

7. The mixed gas compression apparatus for preparing dimethyl carbonate by urea alcoholysis according to claim 6, characterized in that, The top of the gas-mixing compressor (3) is provided with an exhaust pipe (31), and a vacuum pump (32) is provided at one end of the exhaust pipe (31) near the gas-mixing compressor (3).

8. The mixed gas compression apparatus for preparing dimethyl carbonate by urea alcoholysis according to claim 1, characterized in that, The discharge end of the aftercooler (42) is equipped with a circulating feed pipe (5), and the end of the circulating feed pipe (5) away from the aftercooler (42) is connected to the feed end at the bottom of the reactor (1).

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