A system for synthesizing organosilicon monomers effectively utilizes the waste heat of the gas phase of a scrubbing tower

Abstract

The utility model discloses a kind of organic silicon monomer synthesis systems capable of effectively utilizing washing tower gas phase waste heat, including sequentially connected methyl chloride storage tank, vaporizer, superheater, reactor, cyclone separator, washing tower, washing tower condenser and crude monomer tower, waste heat condenser is connected on the pipeline between methyl chloride storage tank and vaporizer, shunt pipe is connected with the lower pipe shell of waste heat condenser, upper pipe shell is connected with superheater by pipeline, heat exchange tube of waste heat condenser is concentrically provided with inner tube, two ends of inner tube are respectively inserted into corresponding pipe shell and then connected with water collecting tank, washing tower and washing tower condenser are communicated with water collecting tank and the upper portion of shell side shell respectively by branch pipe on the pipeline, the lower portion of water collecting tank in lower pipe shell and shell side shell is respectively communicated with the gas inlet of washing tower condenser by reflux pipe.The above, the utility model has the advantages of less heat waste, can reduce operating cost, energy saving and consumption reduction.

Description

Technical Field

[0001] This utility model relates to the technical field of organosilicon monomer synthesis systems, specifically to an organosilicon monomer synthesis system that can effectively utilize the waste heat of the gas phase in a scrubbing tower. Background Technology

[0002] In the production process of organosilicon, the direct synthesis of methylchlorosilane is a crucial step. The process steps are as follows: Liquid chloromethane from a chloromethane storage tank at room temperature is vaporized to 40℃~50℃ using saturated steam. After vaporization, the temperature is raised to 160℃~230℃ using heat transfer oil. The gaseous chloromethane is fed into a fluidized bed reactor to react with silicon powder to generate a methylchlorosilane mixture. The syngas containing fine silicon powder undergoes gas-solid separation in a cyclone separator. The separated syngas enters a scrubbing tower for wet dust removal to remove high boiling points and slurry residue. The solids are returned to the fluidized bed for continued use. The scrubbed syngas is condensed into liquid-phase mixed monomers via circulating water to ensure normal reflux in the scrubbing tower and partial liquid-phase feed to the coarse monomer tower. The uncondensed syngas is used as the gas-phase feed to the coarse monomer tower.

[0003] In the aforementioned process, silicon powder and chloromethane are used as raw materials, and ternary copper is used as a catalyst to carry out a gas-solid reaction in a fluidized bed reactor to produce a mixture of methylchlorosilanes. This reaction is exothermic, and the discharged synthesis gas contains a large amount of heat. This heat is absorbed by the circulating water, resulting in significant heat waste. Furthermore, during system operation, the vaporization of liquid-phase chloromethane often requires a large amount of steam, leading to high vaporization costs and a high energy consumption problem. Therefore, it is objectively necessary to develop an organosilicon monomer synthesis system that minimizes heat waste, reduces operating costs, saves energy, and effectively utilizes the waste heat from the gas phase of the scrubbing tower. Utility Model Content

[0004] The purpose of this invention is to provide an organosilicon monomer synthesis system that effectively utilizes the waste heat of the gas phase in a scrubbing tower, which reduces heat waste, lowers operating costs, and saves energy.

[0005] The purpose of this utility model is achieved as follows: It includes a chloromethane storage tank, a vaporizer, a superheater, a reactor, a cyclone separator, a scrubbing tower, a scrubbing tower condenser, and a crude monomer tower connected in sequence. A waste heat condenser is connected to the pipeline between the chloromethane storage tank and the vaporizer via a branch pipe. The waste heat condenser is a vertical shell-and-tube heat exchanger structure. The branch pipe is connected to the lower tube-side shell of the waste heat condenser. The upper tube-side shell of the waste heat condenser is connected to the superheater via a pipeline. Concentric inner tubes are arranged inside the heat exchange tubes of the waste heat condenser. Both ends of the inner tubes extend into the corresponding tube-side shells and are connected to water collection tanks. A branch pipe is provided on the pipeline between the exhaust port at the top of the scrubbing tower and the scrubbing tower condenser. The branch pipe is connected to the water collection tank in the upper tube-side shell and the upper part of the shell-side shell of the waste heat condenser. The water collection tank in the lower tube-side shell and the lower part of the shell-side shell of the waste heat condenser are connected to the air inlet of the scrubbing tower condenser via reflux pipes.

[0006] Furthermore, a heat exchange tube assembly is installed inside the lower tube side shell of the waste heat condenser, and the inlet of the heat exchange tube assembly is connected to the hot water outlet of the scrubbing tower condenser via a pipeline.

[0007] Furthermore, a drain pipe is provided between the bottom of the upper tube side shell of the waste heat condenser and the branch pipe, and a liquid storage tank and a one-way valve are sequentially arranged on the drain pipe along the liquid flow direction.

[0008] Furthermore, a spiral guide plate is installed on the outer wall of the inner tube inside the heat exchange tube.

[0009] Furthermore, gas mixers are installed on the gas inlet pipeline of the superheater and the gas inlet pipeline of the scrubbing tower condenser.

[0010] Furthermore, a centrifugal separator is installed on the connecting pipeline between the upper tube side shell of the waste heat condenser and the superheater. The liquid outlet at the bottom of the centrifugal separator is connected to the lower tube side shell of the waste heat condenser through a pipeline, and the gas outlet of the centrifugal separator is connected to the superheater through a pipeline.

[0011] This invention relates to a direct method for synthesizing methylchlorosilane in the production of organosilicon. During operation, liquid chloromethane from a chloromethane storage tank at room temperature is vaporized to 40°C–50°C using saturated steam. After vaporization, the temperature is raised to 160°C–230°C using heat transfer oil in a superheater. The vaporized chloromethane is then fed into a reactor to react with silicon powder to generate a methylchlorosilane mixture. The syngas containing fine silicon powder undergoes gas-solid separation via a cyclone separator. The separated syngas enters a scrubbing tower for wet dust removal to remove high-boiling-point dust and slurry residue. The solids are returned to the reactor for reuse. The scrubbed syngas is condensed in the scrubbing tower condenser by circulating water into a liquid-phase mixed monomer to ensure normal reflux in the scrubbing tower and partial liquid-phase feed to the coarse monomer tower. The uncondensed syngas serves as the gas-phase feed to the coarse monomer tower. In this production process, a waste heat condenser is added to condense the syngas from the scrubbing tower. When the syngas is discharged from the top of the tower, it is split. Part of it goes directly into the condenser of the scrubbing tower, and part of it flows into the water collection tank in the upper tube side shell through a branch pipe. This part of the syngas flows into the water collection tank and then splits into each inner tube, flowing from top to bottom along the inner tube, and then flows into the water collection tank in the lower tube side shell. Finally, it returns to the scrubbing tower condenser for further condensation. Another part of the syngas flows into the upper part of the shell side shell through a branch pipe, flows from top to bottom in the shell side shell, and finally returns from the lower part of the shell side shell to the scrubbing tower condenser for further condensation. At the same time, a part of the chloromethane is split off through a branch pipe and fed into the lower tube side shell of the waste heat condenser. Then, it flows from bottom to top in the annular space between the heat exchange tube and the inner tube, absorbing heat from the syngas and vaporizing. The vaporized gaseous chloromethane is sent to the superheater through pipeline to raise the temperature, and then proceeds to the subsequent production process. In this invention, the syngas discharged from the top of the scrubbing tower is divided into three streams: one stream is sent to the scrubbing tower condenser, one stream is sent to the inner tube, and one stream is sent to the shell side. The waste heat in the syngas is used to heat the chloromethane, causing it to vaporize. Similarly, the liquid chloromethane discharged from the chloromethane storage tank is divided into two streams: one stream is sent to the vaporizer, and the other stream is sent to the tube side of the waste heat condenser to absorb the waste heat in the syngas and vaporize. This has two advantages: firstly, it reduces the amount of syngas fed into the original scrubbing tower condenser, thereby reducing the load on the scrubbing tower condenser and reducing the amount of circulating water used during circulation. Firstly, this invention reduces energy consumption by decreasing the amount of chloromethane fed into the original vaporizer, thereby reducing steam consumption within the vaporizer. This effectively reduces, partially replaces, or completely replaces the steam consumption for chloromethane vaporization, achieving energy conservation and cost reduction. It also enables the recycling of waste heat from the syngas in the scrubbing tower, reducing the overall system operating cost. Secondly, this invention utilizes the waste heat of the syngas to heat and vaporize chloromethane. Compared to the traditional structure that only uses circulating water to absorb the waste heat from the syngas, this method directly uses the waste heat of the syngas for system production, improving heat utilization and reducing the waste of syngas waste heat discharged from the scrubbing tower. In summary, this invention has the advantages of low heat waste, reduced operating costs, and energy conservation. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall structure of this utility model; Figure 2 for Figure 1 A magnified structural diagram of node A in the middle; In the diagram: 1-Chloromethane storage tank, 2-Vaporizer, 3-Superheater, 4-Reactor, 5-Cyclone separator, 6-Scrubber, 7-Scrubber condenser, 8-Raw monomer tower, 9-Diverter pipe, 10-Waste heat condenser, 11-Heat exchange tube, 12-Inner tube, 13-Water collection tank, 14-Branch pipe, 15-Reflux pipe, 16-Drain pipe, 17-Storage tank, 18-Spiral guide plate, 19-Gas mixer, 20-Centrifugal separator. Detailed Implementation

[0013] The present invention will be further described below with reference to the accompanying drawings, but this description is not intended to limit the present invention in any way. Any changes or improvements made based on the present invention shall fall within the protection scope of the present invention.

[0014] like Figures 1-2 As shown, this utility model includes a chloromethane storage tank 1, a vaporizer 2, a superheater 3, a reactor 4, a cyclone separator 5, a scrubbing tower 6, a scrubbing tower condenser 7, and a crude monomer tower 8 connected in sequence. The chloromethane storage tank 1, vaporizer 2, superheater 3, reactor 4, cyclone separator 5, scrubbing tower 6, scrubbing tower condenser 7, and crude monomer tower 8 are all existing technologies used for the production of organosilicon. A waste heat condenser 10 is connected to the pipeline between the chloromethane storage tank 1 and the vaporizer 2 via a branch pipe 9. The waste heat condenser 10 is a vertical shell-and-tube heat exchanger structure, including an upper tube shell, a shell-and-tube shell, and a lower tube shell. Heat exchange tubes 11 are installed inside the shell-and-tube shell. A tube sheet is installed, and the branch pipe 9 is connected to the lower tube side shell of the waste heat condenser 10. The upper tube side shell of the waste heat condenser 10 is connected to the superheater 3 via pipeline. An inner tube 12 is concentrically installed inside the heat exchange tubes 11 of the waste heat condenser 10. Both ends of the inner tube 12 extend into the corresponding tube side shells and are connected to a water collection tank 13. A branch pipe 14 is installed between the exhaust port at the top of the scrubbing tower 6 and the scrubbing tower condenser 7. The branch pipe 14 is connected to the water collection tank 13 in the upper tube side shell of the waste heat condenser 10 and the upper part of the shell side shell, respectively. The water collection tank 13 in the lower tube side shell of the waste heat condenser 10 and the lower part of the shell side shell are connected to the air inlet of the scrubbing tower condenser 7 via a return pipe 15. Through the installation of the waste heat condenser 10, the gas phase waste heat of the scrubbing tower 6 can be fully and effectively utilized, and the waste heat can be recycled for the vaporization of chloromethane within the system itself, improving the thermal efficiency of the organosilicon monomer synthesis system and reducing energy waste.

[0015] This invention relates to a direct method for synthesizing methylchlorosilane in the production of organosilicon. During operation, liquid chloromethane from chloromethane storage tank 1 is vaporized to 40°C–50°C using saturated steam. After vaporization, the temperature is raised to 160°C–230°C using heat transfer oil in superheater 3. The vaporized chloromethane is then fed into reactor 4 to react with silicon powder to generate a methylchlorosilane mixture. The syngas containing fine silicon powder undergoes gas-solid separation in cyclone separator 5. The separated syngas enters scrubbing tower 6 for wet dust removal to remove high-boiling-point and slurry residue. The solids are returned to reactor 4 for continued use. The scrubbed syngas is condensed in scrubbing tower condenser 7 by circulating water into a liquid-phase mixed monomer to ensure normal reflux in scrubbing tower 6 and partial liquid-phase feed to coarse monomer tower 8. The uncondensed syngas serves as the gas-phase feed to coarse monomer tower 8. In this production process, a waste heat condenser 10 is added. When the syngas is discharged from the top of scrubbing tower 6… The syngas is divided into two parts. One part enters the condenser 7 of the scrubbing tower directly, while the other part flows through the branch pipe 14 into the water collection tank 13 in the upper tube side shell. This part of the syngas flows into the water collection tank 13 and then into each inner tube 12. It flows from top to bottom along the inner tube 12 and then flows into the water collection tank 13 in the lower tube side shell. Finally, it returns to the scrubbing tower condenser 7 for further condensation. Another part of the syngas flows through the branch pipe 14 into the upper part of the shell side shell. It flows from top to bottom in the shell side shell and finally returns from the lower part of the shell side shell to the scrubbing tower condenser 7 for further condensation. At the same time, a part of the chloromethane is separated through the diversion pipe 9 and fed into the lower tube side shell of the waste heat condenser 10. Then, it flows from bottom to top in the annular space between the heat exchange tube 11 and the inner tube 12, absorbing heat from the syngas and vaporizing. The vaporized gaseous chloromethane is sent to the superheater 3 through the pipeline to raise the temperature and then proceed to the subsequent production process.

[0016] In this invention, the syngas discharged from the top of the scrubbing tower 6 is divided into three streams: one stream is sent to the scrubbing tower condenser 7, one stream is sent to the inner tube 12, and one stream is sent to the shell side. The residual heat in the syngas is used to heat the chloromethane, causing it to vaporize. Similarly, the liquid chloromethane discharged from the chloromethane storage tank 1 is divided into two streams: one stream is sent to the vaporizer 2, and the other stream is sent to the tube side of the waste heat condenser 10 to absorb the residual heat in the syngas and vaporize. This has two advantages: firstly, it reduces the amount of syngas fed into the original scrubbing tower condenser 7, thereby reducing the operating load of the scrubbing tower condenser 7 and reducing the amount of circulating water used. The energy consumption during the process is reduced in two ways: firstly, the amount of chloromethane introduced into the original vaporizer 2 is reduced, thereby reducing the steam consumption in the vaporizer 2. This effectively reduces, partially replaces, or completely replaces the steam consumption for chloromethane vaporization, achieving energy saving and consumption reduction. It also enables the recycling of waste heat from the syngas in the scrubbing tower 6, thus reducing the overall system operating cost. Secondly, in this invention, the waste heat of the syngas is used to heat and vaporize chloromethane. Compared to the traditional structure that only uses circulating water to absorb the waste heat in the syngas, this method absorbs the waste heat of the syngas and directly uses it for the system's production, improving the heat utilization rate and reducing the waste of syngas waste heat discharged from the scrubbing tower 6.

[0017] A heat exchange tube assembly is installed inside the lower tube side shell of the waste heat condenser 10. The inlet of the heat exchange tube assembly is connected to the hot water outlet of the scrubbing tower condenser 7 via a pipeline. The heat exchange tube assembly is an existing heat exchange tube fitting, which can be a spiral tube structure, a serpentine structure, or other structures, as long as it can achieve a good heat exchange effect. In this utility model, circulating water is used to condense the syngas in the scrubbing tower condenser 7. The circulating water absorbs the heat of the syngas and its own temperature rises. In the past, this part of the heat might have been wasted. However, by passing it into the heat exchange tube assembly, it can preheat the chloromethane in the lower tube side shell, improve the vaporization efficiency of chloromethane, and at the same time reduce the waste of heat.

[0018] A drain pipe 16 is installed between the bottom of the upper tube side shell of the waste heat condenser 10 and the distribution pipe 9. A storage tank 17 and a one-way valve are sequentially installed along the liquid flow direction on the drain pipe 16. During system operation, due to operational errors, abnormal operating conditions, or other reasons, liquid chloromethane may accumulate at the bottom of the upper tube side shell. The drain pipe 16 allows it to be discharged promptly and temporarily stored in the storage tank 17, returning to the distribution pipe 9 and then transported to the waste heat condenser 10 for further vaporization. The one-way valve prevents liquid chloromethane in the distribution pipe 9 from entering the storage tank 17.

[0019] A spiral guide plate 18 is provided on the outer wall of the inner tube 12 inside the heat exchange tube 11. The spiral guide plate 18 is located in the annular space between the inner tube 12 and the heat exchange tube 11. In this invention, liquid chloromethane also flows upward from this annular space. The spiral guide plate 18 can guide the chloromethane, allowing it to flow spirally upward within the annular space. This prolongs the residence time of the chloromethane in the annular space, thereby improving the vaporization effect and preventing incomplete vaporization. In practical applications, the spiral guide plate 18 can also be made of a material with good thermal conductivity, giving it a heat-conducting function and further improving the heat exchange efficiency between the synthesis gas and chloromethane in the inner tube 12.

[0020] Gas mixers 19 are installed on the gas inlet pipeline of superheater 3 and the gas inlet pipeline of scrubbing tower condenser 7. Gas mixers 19 are existing equipment used for uniform mixing of multiple gases. When this utility model is in operation, there are two streams of gaseous chloromethane entering superheater 3, one from vaporizer 2 and the other from waste heat condenser 10. Vaporizer 2 uses steam as a heat source, and waste heat condenser 10 uses syngas as a heat source. Due to the different heat sources and operating conditions, the temperature of the vaporized chloromethane gas will also be different. If it is directly introduced into superheater 3, it may cause instability in the operating conditions of superheater 3 and affect the thermal efficiency of superheater 3. To avoid this situation, the two gas streams are mixed by gas mixers 19 to evenly deliver the gas temperature to superheater 3, thereby stabilizing and improving the working efficiency of superheater 3. Similarly, three streams of syngas enter the scrubbing tower condenser 7: one comes directly from the scrubbing tower 6, another from the shell side of the waste heat condenser 10, and the third from the inner tube 12 of the waste heat condenser 10. The latter two streams of syngas are used to heat and vaporize liquid chloromethane, but their operating states are different. Therefore, after the vaporization of liquid chloromethane is completed, the temperature of the syngas itself is still different. Thus, the temperatures of the three streams of syngas are all different. If they are directly introduced into the scrubbing tower condenser 7, it may cause the operating conditions of the scrubbing tower condenser 7 to be unstable, which will affect the thermal efficiency of the scrubbing tower condenser 7. To avoid this situation, the three streams of gas are mixed by the gas mixer 19 to average the temperature of the gas delivered to the scrubbing tower condenser 7, thereby stabilizing and improving the operating efficiency of the scrubbing tower condenser 7.

[0021] A centrifugal separator 20 is installed on the connecting pipeline between the upper tube shell of the waste heat condenser 10 and the superheater 3. The liquid outlet at the bottom of the centrifugal separator 20 is connected to the lower tube shell of the waste heat condenser 10 through a pipeline, and the gas outlet of the centrifugal separator 20 is connected to the superheater 3 through a pipeline. The centrifugal separator 20 is an existing device that uses centrifugal force as the main separation principle to separate components of different densities in a mixture. The vaporized chloromethane gas, carrying some chloromethane droplets, enters a conical container at high speed along the tangential direction, forming a rotating airflow. The denser droplets are thrown towards the wall under the action of centrifugal force and slide down the wall, while the purified gas is discharged from the middle upwards. In operation, this invention utilizes the waste heat condenser 10 to vaporize liquid chloromethane. Due to the excessively high gas flow rate, or the fact that a small portion of the chloromethane is not fully vaporized, droplets may be carried in the gaseous chloromethane. This can damage downstream equipment, corrode and erode pipes and valves, and may also affect the heat transfer efficiency of the subsequent superheater 3. To avoid these problems, a centrifugal separator 20 is installed to remove droplets from the chloromethane gas. The separated droplets are collected and returned to the waste heat condenser 10 for further vaporization.

[0022] After the waste heat condenser was installed, practical verification showed that the amount of steam consumed in the vaporization of liquid chloromethane could be reduced. When using 0.5MPa saturated steam, 8 to 10 tons of 0.5MPa saturated steam could be saved per hour, reducing the production cost of enterprises. At the same time, it effectively solved the problem of wasted heat at the outlet of the organosilicon monomer synthesis washing tower 6, and promoted the progress of organosilicon monomer synthesis technology.

Claims

1. An organosilicon monomer synthesis system that can effectively utilize the waste heat of the gas phase of a scrubbing tower, comprising a chloromethane storage tank (1), a vaporizer (2), a superheater (3), a reactor (4), a cyclone separator (5), a scrubbing tower (6), a scrubbing tower condenser (7), and a crude monomer tower (8) connected in sequence, characterized in that: A waste heat condenser (10) is connected to the pipeline between the chloromethane storage tank (1) and the vaporizer (2) via a branch pipe (9). The waste heat condenser (10) is a vertical shell-and-tube heat exchanger. The branch pipe (9) is connected to the lower tube side shell of the waste heat condenser (10), and the upper tube side shell of the waste heat condenser (10) is connected to the superheater (3) via a pipeline. An inner tube (12) is concentrically arranged inside the heat exchange tubes (11) of the waste heat condenser (10), and both ends of the inner tube (12) extend into the corresponding... A water collection tank (13) is connected to the inner tube side shell of the washing tower (6). A branch pipe (14) is provided on the pipeline between the exhaust port at the top of the washing tower (6) and the washing tower condenser (7). The branch pipe (14) is connected to the water collection tank (13) in the upper tube side shell of the waste heat condenser (10) and the upper part of the shell side shell. The water collection tank (13) in the lower tube side shell of the waste heat condenser (10) and the lower part of the shell side shell are connected to the air inlet of the washing tower condenser (7) through the return pipe (15).

2. The organosilicon monomer synthesis system according to claim 1, which can effectively utilize the waste heat of the gas phase in a scrubbing tower, is characterized in that: The waste heat condenser (10) is equipped with a heat exchange tube assembly in the lower tube side shell, and the inlet of the heat exchange tube assembly is connected to the hot water outlet of the washing tower condenser (7) through a pipeline.

3. The organosilicon monomer synthesis system according to claim 1, which can effectively utilize the waste heat of the gas phase in a scrubbing tower, is characterized in that: A drain pipe (16) is provided between the bottom of the upper tube shell of the waste heat condenser (10) and the branch pipe (9). A storage tank (17) and a one-way valve are arranged sequentially on the drain pipe (16) along the liquid flow direction.

4. The organosilicon monomer synthesis system according to claim 1, which can effectively utilize the waste heat of the gas phase in a scrubbing tower, is characterized in that: A spiral guide plate (18) is provided on the outer wall of the inner tube (12) inside the heat exchange tube (11).

5. The organosilicon monomer synthesis system according to claim 1, which can effectively utilize the waste heat of the gas phase in a scrubbing tower, is characterized in that: Gas mixers (19) are installed on the gas inlet pipeline of the superheater (3) and the gas inlet pipeline of the scrubbing tower condenser (7).

6. The organosilicon monomer synthesis system according to claim 1, which can effectively utilize the waste heat of the gas phase in a scrubbing tower, is characterized in that: A centrifugal separator (20) is installed on the connecting pipeline between the upper tube side shell of the waste heat condenser (10) and the superheater (3). The liquid outlet at the bottom of the centrifugal separator (20) is connected to the lower tube side shell of the waste heat condenser (10) through a pipeline, and the gas outlet of the centrifugal separator (20) is connected to the superheater (3) through a pipeline.

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