Cold hydrogenation synthesizer

Abstract

The utility model discloses a cold hydrogenation synthesis device which comprises a gas-liquid separation tank and a crude TCS condenser, the gas-liquid separation tank is used for separating non-condensable gas and chlorosilane, the chlorosilane refers to silicon tetrachloride, silicon trichloride and dichlorosilane, an intermediate heat exchanger is arranged between the gas-liquid separation tank and the crude TCS condenser, and the intermediate heat exchanger is used for heating the crude TCS condenser. Liquid flowing out of the gas-liquid separation tank and gas vaporized by the coarse TCS condenser are suitable for heat exchange in the intermediate heat exchanger. According to the cold hydrogenation synthesis device, through the arrangement of the intermediate heat exchanger, the cooling capacity of the liquid phase of the gas-liquid separation tank in a conventional process is utilized, the utilization effect of energy in the process is improved, the condensation effect of chlorosilane is improved, and maximum utilization of resources is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of polysilicon production equipment, and in particular to a cold hydrogenation synthesis device. Background Art

[0002] In the existing cold hydrogenation process for producing trichlorosilane, the reactants such as hydrogen and silicon tetrachloride are first heated from room temperature and enter the fluidized bed reactor to react with silicon powder. The mixed gas in the reaction product includes trichlorosilane, a small amount of dichlorosilane and unreacted silicon tetrachloride, hydrogen and a small amount of hydrogen chloride. The mixed gas is sent to the terminal condenser after washing and impurity removal. Chlorosilanes such as silicon tetrachloride, silicon trichloride and dichlorosilane are condensed in the terminal condenser, and the uncondensed hydrogen and hydrogen chloride gas are sent to the buffer tank and then re-entered into the cold hydrogenation system for trichlorosilane production for reuse. The chlorosilane material condensed in the terminal condenser enters the subsequent separation and purification system to further separate silicon tetrachloride from other substances. The separated silicon tetrachloride re-enters the system, and silanes such as silicon trichloride and dichlorosilane enter the chlorosilane storage tank for use in the reduction process.

[0003] In recent years, with the continuous improvement of global environmental awareness and the increasing energy pressure, low-carbon economy has become an important development strategy for all countries. Promoting sustainable development on the basis of reducing greenhouse gas emissions and saving energy is a development model of low-carbon economy. The development and application of chemical process energy-saving technology has become an important research direction under the low-carbon economy situation. By improving production processes, optimizing equipment structure and other means, it can reduce chemical production energy consumption and environmental pollution, improve production efficiency, reduce production costs and enhance competitiveness. The development of chemical process energy-saving technology will be conducive to protecting the environment, reducing energy consumption, and promoting the healthy development of low-carbon economy. Summary of the invention

[0004] The purpose of the present application is to improve the energy utilization rate in a cold hydrogenation synthesis device.

[0005] In order to achieve the above objectives, the technical solution adopted in the present application is: to provide a cold hydrogenation synthesis device, including a gas-liquid separation tank and a crude TCS condenser, the gas-liquid separation tank is used to separate non-condensable gas and chlorosilane, the chlorosilane refers to silicon tetrachloride, silicon trichloride and dichlorodihydrosilane, an intermediate heat exchanger is arranged between the gas-liquid separation tank and the crude TCS condenser, and the liquid flowing out of the gas-liquid separation tank and the gas vaporized from the crude TCS condenser are suitable for heat exchange in the intermediate heat exchanger.

[0006] As a preference, the liquid flowing out of the gas-liquid separation tank enters the shell side of the intermediate heat exchanger, and enters the crude TCS condenser after being heated in the intermediate heat exchanger.

[0007] As another preferred embodiment, the gas flowing out of the crude TCS condenser enters the tube side of the intermediate heat exchanger, is cooled in the intermediate heat exchanger, and obtains condensed liquid and uncondensed gas.

[0008] As another preferred embodiment, the condensed liquid re-enters the crude TCS condenser from the tube side of the intermediate heat exchanger, and the uncondensed gas is used to supplement the hydrogen system.

[0009] As another preferred embodiment, it further comprises a flash cooler, wherein the uncondensed gas flowing out from the tube side of the intermediate heat exchanger enters the flash cooler.

[0010] As another preferred embodiment, the liquid flowing out of the flash cooler enters the crude TCS condenser, and the gas flowing out of the flash cooler goes to the hydrogen supplement system.

[0011] As another preference, in the flash cooler, the supply amount of cooling liquid is adjusted so that the temperature of the gas from the flash cooler to the hydrogen supplementation system is not higher than -30°C.

[0012] As another preferred embodiment, the liquid flowing out of the crude TCS condenser enters a subsequent distillation process.

[0013] As another preference, the intermediate heat exchanger is provided with an exhaust valve, which controls the communication between the intermediate heat exchanger and the crude TCS condenser, and is used to balance the gas pressure of the intermediate heat exchanger.

[0014] Further preferably, the intermediate heat exchanger is provided with a regulating valve, the regulating valve is arranged on the pipeline through which the shell-side liquid of the intermediate heat exchanger flows into the crude TCS condenser, and the regulating valve is used to adjust the liquid level of the gas-liquid separation tank.

[0015] Compared with the prior art, the beneficial effects of this application are:

[0016] (1) The cold hydrogenation synthesis device of the present application utilizes the cold energy of the liquid phase of the gas-liquid separation tank in the conventional process by setting up an intermediate heat exchanger, thereby improving the utilization effect of energy in the process, enhancing the condensation effect of chlorosilane, and realizing maximum utilization of resources;

[0017] (2) The cold hydrogenation synthesis device of the present application reduces the usage of cooling liquid Freon in the flash cooler by setting up an intermediate heat exchanger, thereby saving resources and reducing pollution to the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a process flow chart of an embodiment of the present application;

[0019] In the figure: 1. gas-liquid separation tank; 2. crude TCS condenser; 3. intermediate heat exchanger; 31. exhaust valve; 32. regulating valve; 4. flash cooler. DETAILED DESCRIPTION

[0020] Below, the present application is further described in conjunction with specific implementation methods. It should be noted that, under the premise of no conflict, the various embodiments or technical features described below can be arbitrarily combined to form new embodiments.

[0021] In the description of the present application, it should be noted that directional words, such as the terms "center", "lateral", "longitudinal", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating directions and positional relationships are based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of narrating the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and cannot be understood as limiting the specific scope of protection of the present application.

[0022] It should be noted that the terms "first", "second", etc. in the description and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence.

[0023] The terms "including" and "having" and any variations thereof in the specification and claims of this application are intended to cover non-exclusive inclusions. For example, a process, method, system, product or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to these processes, methods, products or apparatuses.

[0024] like Figure 1 As shown, the cold hydrogenation synthesis device of the present application includes a gas-liquid separation tank 1 and a crude TCS condenser 2, and an intermediate heat exchanger 3 is arranged between the gas-liquid separation tank 1 and the crude TCS condenser 2. With the arrangement of the intermediate heat exchanger 3, the liquid flowing out of the gas-liquid separation tank 1 and the vaporized gas in the crude TCS condenser 2 exchange heat in the intermediate heat exchanger 3, and the intermediate heat exchanger 3 can utilize the heat of chlorosilane in the crude TCS condenser 2 to achieve the purpose of heating the liquid flowing out of the gas-liquid separation tank 1.

[0025] The provision of the intermediate heat exchanger 3 can save the usage of cooling liquid Freon in the additional cooler, thereby saving electricity resources and refrigerant resources, making the cold hydrogenation synthesis device more environmentally friendly and maximizing resource utilization.

[0026] The gas-liquid separation tank 1 separates chlorosilane from non-condensable gas, wherein chlorosilane mainly refers to silicon tetrachloride, silicon trichloride, and silicon dichloride, and the non-condensable gas is unreacted hydrogen and a small amount of hydrogen chloride gas. The chlorosilane separated by the gas-liquid separation tank 1 enters the shell side of the intermediate heat exchanger 3.

[0027] The crude TCS condenser 2 is provided with a chlorosilane liquid inlet. Due to the change in the pressure in the tank, the liquid chlorosilane flashes and vaporizes rapidly in the crude TCS condenser 2, usually at a temperature of about 60°C and a pressure of 0.9 MPa. The flashed gas phase of the crude TCS condenser enters the tube side of the intermediate heat exchanger 3 and exchanges heat with the liquid phase of the gas-liquid separation tank 1.

[0028] In some embodiments, the liquid phase of the gas-liquid separation tank 1 enters the shell side of the intermediate heat exchanger 3, and after being heated, enters the crude TCS condenser 2. The flashed gas phase of the crude TCS condenser 2 enters the tube side of the intermediate heat exchanger 3, and after cooling, condensed liquid and uncondensed gas are obtained, wherein the condensed liquid is mainly condensed chlorosilane, and the uncondensed gas includes non-condensable gases such as hydrogen and hydrogen chloride, and also includes uncondensed chlorosilane gas.

[0029] The flashed gas phase of the crude TCS condenser 2 is cooled by the intermediate heat exchanger 3 and the condensed liquid re-enters the crude TCS condenser, while the uncondensed gas goes to the subsequent hydrogen replenishment system.

[0030] The chlorosilane liquid flowing out of the crude TCS condenser 2 enters the subsequent distillation process.

[0031] In some embodiments, the cold hydrogenation synthesis device of the present application further includes a flash cooler 4, and the uncondensed gas flowing out from the tube side of the intermediate heat exchanger 3 enters the flash cooler 4, and the cooling liquid cools the uncondensed gas again in the flash cooler 4. The non-condensable gas flowing out of the flash cooler 4 goes to the hydrogen supplement system, and the liquefied chlorosilane liquid enters the crude TCS condensation tower 2.

[0032] When the system is started or at low load, the supply of cooling liquid in the flash cooler 4 is adjusted so that the temperature of the non-condensable gas going to the hydrogen replenishment system is not higher than -30°C, thereby ensuring the condensation effect of chlorosilane and preventing chlorosilane gas from going to the hydrogen replenishment system and affecting the operation of the hydrogen compressor.

[0033] In some embodiments, the intermediate heat exchanger 3 is provided with an exhaust valve 31, and the exhaust valve 32 is used to control the communication between the intermediate heat exchanger 3 and the crude TCS condenser 2. When the system is operating normally, the exhaust valve 31 is closed. When the system stops operating, the exhaust valve 31 can be opened periodically to exhaust gas to balance the air pressure in the intermediate heat exchanger 3.

[0034] In some embodiments, the intermediate heat exchanger 3 is provided with a regulating valve 32, which is arranged on the pipe where the shell-side liquid of the intermediate heat exchanger 3 flows into the crude TCS condenser 2. The regulating valve 32 is also connected to the remote level gauge of the gas-liquid separation tank 1 and the lower liquid remote temperature gauge of the intermediate heat exchanger 3.

[0035] The regulating valve 32 is adjusted to a fixed flow value to ensure that the liquid level of the enterprise separation tank 1 is maintained at 50% to 55%. Due to system adjustment and other reasons, the liquid level in the gas-liquid separation tank 1 fluctuates. In order to ensure the uniform and stable flow of the intermediate heat exchanger 3, the regulating valve 32 is connected and interlocked with the liquid level of the gas-liquid separation tank 1, that is, when the liquid level in the gas-liquid separation tank 1 is lower than 45%, the regulating valve 32 is rapidly increased to the first opening value until the liquid level in the gas-liquid separation tank 1 is in an ascending state. In addition, the regulating valve 32 is interlocked with the flow meter in the pipeline to the minimum flow value to ensure the continuous and stable heat exchange of the intermediate heat exchanger 3.

[0036] The cold hydrogenation synthesis device of the present application utilizes the coldness of the liquid phase of the gas-liquid separation tank 1 in the conventional process by setting up the intermediate heat exchanger 3, thereby improving the utilization effect of energy in the process, enhancing the condensation effect of chlorosilane, and realizing maximum utilization of resources.

[0037] The above describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments, and the above embodiments and the specification only describe the principles of the present application. The present application may have various changes and improvements without departing from the spirit and scope of the present application, and these changes and improvements fall within the scope of the present application for which protection is sought. The scope of protection claimed by the present application is defined by the attached claims and their equivalents.

Claims

1. A cold hydrogenation synthesis device, comprising a gas-liquid separation tank and a crude TCS condenser, wherein the gas-liquid separation tank is used to separate non-condensable gas and chlorosilane, wherein the chlorosilane refers to silicon tetrachloride, silicon trichloride and dichlorodihydrosilane, characterized in that: An intermediate heat exchanger is provided between the gas-liquid separation tank and the crude TCS condenser, and the liquid flowing out of the gas-liquid separation tank and the gas vaporized from the crude TCS condenser are suitable for heat exchange in the intermediate heat exchanger.

2. The cold hydrogenation synthesis device according to claim 1, characterized in that: The liquid flowing out of the gas-liquid separation tank enters the shell side of the intermediate heat exchanger, and enters the crude TCS condenser after being heated in the intermediate heat exchanger.

3. The cold hydrogenation synthesis device according to claim 1, characterized in that: The gas flowing out of the crude TCS condenser enters the tube side of the intermediate heat exchanger, where it is cooled to obtain condensed liquid and uncondensed gas.

4. The cold hydrogenation synthesis device according to claim 3, characterized in that: The condensed liquid re-enters the crude TCS condenser from the tube side of the intermediate heat exchanger, and the uncondensed gas is used to supplement the hydrogen system.

5. The cold hydrogenation synthesis device according to claim 4, characterized in that: It also includes a flash cooler, and the uncondensed gas flowing out from the tube side of the intermediate heat exchanger enters the flash cooler.

6. The cold hydrogenation synthesis device according to claim 5, characterized in that: The liquid flowing out of the flash cooler enters the crude TCS condenser, and the gas flowing out of the flash cooler goes to the supplementary hydrogen system.

7. The cold hydrogenation synthesis device according to claim 5, characterized in that: In the flash cooler, the supply amount of cooling liquid is adjusted so that the temperature of the gas from the flash cooler to the hydrogen supplement system is not higher than -30°C.

8. The cold hydrogenation synthesis device according to claim 1, characterized in that: The liquid flowing out of the crude TCS condenser enters the subsequent distillation process.

9. The cold hydrogenation synthesis device according to claim 1, characterized in that: The intermediate heat exchanger is provided with an exhaust valve, which controls the communication between the intermediate heat exchanger and the crude TCS condenser, and is used to balance the gas pressure of the intermediate heat exchanger.

10. The cold hydrogenation synthesis device according to claim 2, characterized in that: The intermediate heat exchanger is provided with a regulating valve, which is arranged on a pipeline through which the shell-side liquid of the intermediate heat exchanger flows into the crude TCS condenser, and is used to adjust the liquid level of the gas-liquid separation tank.

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