Energy-saving type silane production and purification system

Abstract

The invention relates to the field of silane production, and discloses an energy-saving type silane production and purification system which comprises a production unit used for converting trichlorosilane into silane gas and a chlorosilane compound and carrying out preliminary separation treatment on the silane gas and the chlorosilane compound. According to the invention, a disproportionation reaction rectification method is adopted, after pressurization by a compressor, the temperature and pressure of silane gas and other chlorosilane compounds are increased, and the boiling point of the chlorosilane compounds is increased, so that the chlorosilane compounds are more easily liquefied at a higher temperature, more effective condensation and separation in a precooler are facilitated, and the yield of the chlorosilane compounds is improved. And through the cooling effect of the precooler, part of the chlorosilane compound is condensed into a liquid state, so that preliminary separation of the chlorosilane compound and gaseous silane gas is realized, part of impurities are removed in advance, the content of the impurities entering the silane separation tower is reduced, and the separation efficiency of the separation tower is improved.

Description

Technical Field

[0001] This invention relates to the field of silane production, in particular to an energy-saving silane production and purification system. Background Art

[0002] Silane gas is an electronic special gas and is widely used in many fields such as photovoltaic, integrated circuit, display panel, solar cell, thin film transistor, advanced ceramics, etc.

[0003] Currently, the methods for preparing silane include four types: fluorosilicon method, chlorosilicon method, magnesium-silicon method, and lithium-silicon method; among them, the chlorosilicon method (also known as disproportionation method) is the main production process, and it is further divided into a two-step method and a reactive distillation method, which means using trichlorosilane as the raw material and obtaining silane through a disproportionation reaction. The two-step method has advantages such as high product purity and high raw material utilization rate, but has disadvantages such as a relatively complex production process, low reaction conversion rate, and high equipment requirements. Compared with the traditional two-step method, the reactive distillation technology has advantages such as high reaction conversion rate and relatively low energy consumption, and can be used for large-scale production, but also has deficiencies such as high operating energy consumption and more trace-level impurity components.

[0004] Based on the improvement of the reactive distillation process, this invention improves the product quality of silane, greatly reduces the operating energy consumption of silane production, reduces the usage amount of refrigerant, and saves resources. Summary of the Invention

[0005] Therefore, the technical problem to be solved by this invention is that the operating energy consumption of silane production is relatively high.

[0006] The above technical problem is solved by the following technical solutions: This invention provides an energy-saving silane production and purification system, including, A production unit, which is used to convert trichlorosilane into silane gas and chlorosilane compounds, and conduct preliminary separation treatment on the silane gas and chlorosilane compounds; A separation unit, including a silane separation tower, which is used to deeply separate the preliminarily treated silane gas from other impurities, and the impurities include but are not limited to monochlorosilane, dichlorosilane, hydrogen, and nitrogen, so as to improve the purity of silane; A separation tower condenser, which is used to condense the silane gas discharged from the top of the silane separation tower, so as to achieve the liquefaction of silane and the separation of impurities; A pre-cooler, which is used to pre-cool the silane gas before the silane separation tower, so as to reduce the temperature of the silane gas and achieve the condensation of some impurities; The pre-cooler is connected to the separation tower condenser, and is used to receive the refrigerant from the separation tower condenser and pre-cool the silane gas with the refrigerant; A compressor, which is used to pressurize the silane gas before the pre-cooler, so as to increase the pressure of the silane gas; A purification unit, which is used to remove trace impurities in silane gas and further purify the silane gas by rectification; A circulation unit, which is used for the recycling of refrigerant.

[0007] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the production unit includes, A silane reaction tower, which is used to convert trichlorosilane into silane gas and other chlorosilane compounds; A reboiler of the reaction tower, which is connected to the silane reaction tower and is used to provide heat for the silane reaction tower to maintain the temperature required for the reaction; A first condenser, which is connected to the silane reaction tower and is used to condense part of the chlorosilane compounds discharged from the top of the silane reaction tower; A second condenser, which is connected to the first condenser and is used to further condense the uncondensed silane gas and other chlorosilane compounds; A gas-liquid separation tank, which is connected to the second condenser and is used to separate the condensed liquid substances and the uncondensed gaseous silane; The outlet of the gas-liquid separation tank is connected to the inlet of the compressor, which is used to transport the separated gaseous silane to the compressor.

[0008] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the production unit further includes, An outlet buffer tank, which is connected to the outlet of the compressor and is used to stabilize the pressure of the pressurized silane gas;

[0009] The outlet of the outlet buffer tank is connected to the inlet of the pre-cooler, which is used to transport the pressurized silane gas to the pre-cooler.

[0010] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the production unit further includes, A reaction tower reflux tank, which is connected to the liquid phase outlets of the first condenser, the second condenser and the pre-cooler and is used to collect the condensed liquid chlorosilane and reflux it to the silane reaction tower; A pressurizing pump, which is connected to the reaction tower reflux tank and is used to pressurize the reflux liquid and transport it back to the silane reaction tower.

[0011] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the impurities discharged from the bottom of the silane separation tower are refluxed to the silane reaction tower to realize the recycling of materials.

[0012] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the purification unit includes, An adsorption column, which is connected to the silane separation column and is used to adsorb and remove trace impurities in the silane gas, and the trace impurities include boron and phosphorus; A silane purification column, which is used to further purify the silane gas by distillation to obtain a high-purity silane product; The inlet of the silane purification column is connected to the outlet of the adsorption column, and it is used to receive the silane gas that has undergone adsorption treatment;

[0013] The outlet of the silane purification column is used to output a high-purity silane product.

[0014] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the purification unit further includes, A reboiler for the purification column, which is connected to the silane purification column and is used to provide heat for the silane purification column to maintain the operating temperature inside the column;

[0015] A condenser for the purification column, which is connected to the silane purification column and is used to condense the silane gas discharged from the top of the silane purification column.

[0016] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the purification unit further includes, A reboiler for the separation column, which is connected to the reboiler for the reaction column and the silane separation column, and is used to receive the heat medium from the reboiler for the reaction column and use the heat medium to provide heat for the silane separation column to achieve full utilization of waste heat.

[0017] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the adsorption column is filled with an adsorbent, and the adsorbent includes but is not limited to activated carbon, molecular sieve, silica, resin, zeolite or metal oxide, and is used to remove trace impurities in the silane gas.

[0018] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the circulation unit includes a chilled water device and chilled water pipelines, and the chilled water device distributes the refrigerant to the first chilled water pipeline and the second chilled water pipeline. Among them, the refrigerant in the second chilled water pipeline flows out through the third chilled water pipeline after heat exchange through the separation column condenser, and the refrigerant in the first chilled water pipeline flows out through the fourth chilled water pipeline after heat exchange through the purification column condenser.

[0019] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the third chilled water pipeline and the fourth chilled water pipeline distribute the refrigerant to the fifth chilled water pipeline and the sixth chilled water pipeline respectively. Among them, the refrigerant in the fifth chilled water pipeline flows out through the seventh chilled water pipeline after heat exchange through the second condenser, and the refrigerant in the sixth chilled water pipeline flows out through the eighth chilled water pipeline after heat exchange through the first condenser.

[0020] In a preferred embodiment of the energy-saving silane production and purification system of the present invention: the seventh chilled water pipeline and the eighth chilled water pipeline distribute the refrigerant to the ninth chilled water pipeline. Among them, the refrigerant in the ninth chilled water pipeline flows out through the tenth chilled water pipeline after heat exchange in the pre-cooler and returns to the chilled water equipment for recycling.

[0021] The beneficial effects of the present invention are as follows: The present invention adopts the method of disproportionation reaction distillation. After being pressurized by a compressor, the temperature and pressure of silane gas and other chlorosilane compounds increase, and the boiling point of chlorosilane compounds rises, making it easier for chlorosilane compounds to liquefy at a higher temperature, which helps to achieve more effective condensation and separation in the pre-cooler. Moreover, through the cooling effect of the pre-cooler, part of the chlorosilane compounds are condensed into liquid state, thus achieving a preliminary separation from gaseous silane gas, and part of the impurities are removed in advance, reducing the impurity content entering the silane separation tower, improving the separation efficiency of the separation tower, and reducing the operation load of the separation tower.

[0022] Due to the increase in the boiling point of chlorosilane compounds, the pre-cooler can achieve condensation at a relatively high temperature, reducing the demand for low-temperature refrigerant, reducing the consumption of refrigerant, and reducing the energy consumption of the cooling system.

[0023] The pre-cooler utilizes the waste heat from the condenser of the separation tower as the refrigerant, realizing the recycling of heat and further improving the energy utilization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below only relate to some embodiments of the present invention and do not limit the present invention. Among them: Figure 1 Shows a schematic connection diagram of the separation unit in the energy-saving silane production and purification system; Figure 2 Shows a distribution diagram of the production unit, separation unit, and purification unit in the energy-saving silane production and purification system; Figure 3 Shows a distribution diagram of the production unit, separation unit, purification unit, and recycling unit in the energy-saving silane production and purification system; Figure 4 Shows a schematic overall connection diagram of the energy-saving silane production and purification system; Figure 5 Shows a schematic diagram of the circulation of chilled water in the recycling unit of the energy-saving silane production and purification system. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below in conjunction with specific embodiments and the accompanying drawings.

[0026] The terms used in the present invention are those general terms that are currently widely used in the art in consideration of the functions of the present invention. However, these terms may vary according to the intentions of those of ordinary skill in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather based on the meanings of the terms and the overall description of the present invention.

[0027] Referring to Figure 1 and Figure 3 , this embodiment provides an energy-saving silane production and purification system, including a production unit 200 and a purification unit 300.

[0028] Among them, the production unit 200 is used to convert trichlorosilane into silane gas and chlorosilane compounds, and separate the silane gas and chlorosilane compounds. The purification unit 300 is used to remove trace impurities in the silane gas and further purify the silane gas by rectification.

[0029] The present invention is provided with a silane separation tower 101, a separation tower condenser 102, a pre-cooler 103, and a compressor 104 between the production unit 200 and the purification unit 300.

[0030] Among them, the silane separation tower 101 is used to deeply separate the preliminarily treated silane gas from other impurities, and the impurities include but are not limited to monochlorosilane, dichlorosilane, hydrogen, and nitrogen, so as to improve the purity of the silane. The separation tower condenser 102 is used to condense the silane gas discharged from the top of the silane separation tower 101 to achieve the liquefaction of the silane and the separation of the impurities. The pre-cooler 103 is used to pre-cool the silane gas before the silane separation tower 101 to reduce the temperature of the silane gas and achieve the condensation of some impurities. The compressor 104 is used to pressurize the silane gas before the pre-cooler 103 to increase the pressure of the silane gas. The pre-cooler 103 is connected to the separation tower condenser 102, and the pre-cooler 103 receives the refrigerant from the separation tower condenser 102 and uses the refrigerant to pre-cool the silane gas.

[0031] Furthermore, after being pressurized by the compressor 104, the temperature and pressure of the silane gas and other chlorosilane compounds increase. During the subsequent condensation process in the pre-cooler 103, the chlorosilane compounds are more easily condensed into the liquid phase. The improvement in the efficiency of the condensation process can reduce the amount of refrigerant required for condensation, thereby reducing energy consumption. At the same time, due to the increase in pressure, the chlorosilane compound gas that cannot be condensed under normal pressure is condensed, reducing the impurities in the silane gas, thereby achieving the effect of preliminary impurity removal. This not only reduces the operating load of the subsequent silane separation tower 101 but also improves the purity of silane purification.

[0032] Furthermore, there is a relatively high pressure inside the silane separation tower 101. The compressor 104 can stably transport the separated silane gas-phase material to the silane separation tower 101, ensuring the pressure balance of the entire system and the stability of the material flow. Without the compressor 104, the pressure of the silane will be unstable, affecting the operating efficiency and product quality of the silane separation tower 101.

[0033] During use, the gas-phase material mainly composed of silane enters the compressor 104. After being pressurized by the compressor 104, the gas-phase material mainly composed of silane is discharged to the outlet of the compressor 104. The gas-phase material exiting from the outlet of the compressor 104 enters the silane separation tower 101 for deep separation after passing through the separation tower condenser 102. In the silane separation tower 101, the silane and a small amount of materials such as monochlorosilane entrained are separated. The monochlorosilane is discharged from the bottom of the silane separation tower 101. The silane and a small amount of hydrogen, nitrogen, and other hydrogen components entrained are taken out from the top of the silane separation tower 101 and first pass through the separation tower condenser 102. After condensation, the silane is condensed into the liquid phase and reflows into the silane separation tower 101. The small amount of uncondensed hydrogen and nitrogen are discharged from the exhaust port of the heat exchanger. High-purity silane is taken out from the side of the silane separation tower 101.

[0034] Refer to Figure 2 and Figure 4 , the production unit 200 includes a silane reaction tower 201, a reaction tower reboiler 202, a first condenser 203, a second condenser 204, and a gas-liquid separation tank 205.

[0035] Among them, the silane reaction tower 201 is used to convert trichlorosilane into silane gas and other chlorosilane compounds. The reboiler 202 of the reaction tower is connected to the silane reaction tower 201 and is used to provide heat for the silane reaction tower 201 to maintain the temperature required for the reaction. The first condenser 203 is connected to the silane reaction tower 201 and is used to condense part of the chlorosilane compounds discharged from the top of the silane reaction tower 201. The second condenser 204 is connected to the first condenser 203 and is used to further condense the uncondensed silane gas and other chlorosilane compounds. The gas-liquid separation tank 205 is connected to the second condenser 204 and is used to separate the condensed liquid substance and the uncondensed gaseous silane. The outlet of the gas-liquid separation tank 205 is connected to the inlet of the compressor 104 and is used to transport the separated gaseous silane to the compressor 104.

[0036] Further, inside the silane reaction tower 201, trichlorosilane generates products such as silane gas, monochlorosilane, dichlorosilane, and silicon tetrachloride through disproportionation reaction.

[0037] The reboiler 202 of the reaction tower promotes the reaction by heating the material at the bottom of the reaction tower, ensuring the continuity and stability of the reaction. Through the heat provided by the reboiler 202 of the reaction tower, the reaction inside the reaction tower can proceed efficiently, ensuring the stable production of silane.

[0038] The first condenser 203 realizes preliminary separation by reducing the temperature of the gaseous product to partially condense it into a liquid state. Through the condensation effect, part of the high-boiling-point chlorosilane compounds are condensed into a liquid state, reducing the processing load of subsequent equipment.

[0039] The second condenser 204 ensures the efficient progress of the multi-stage condensation process by further reducing the temperature of the gaseous product, improving the separation efficiency. Through multi-stage condensation, the impurity content in the gaseous product is further reduced, and the purity of the silane gas is improved.

[0040] The gas-liquid separation tank 205 separates the liquid chlorosilane compounds from the gaseous silane gas, reducing the entrainment of liquid impurities. The gas-liquid separation tank 205 not only functions to separate gas and liquid but also buffers the inlet of the compressor 104 to prevent the compressor 104 from carrying liquid. The gas-liquid separation tank 205 has a dual function.

[0041] Refer to Figure 2 and Figure 4 As shown in

[0042] Among them, the outlet buffer tank 207 is connected to the outlet of the compressor 104 and is used to stabilize the pressure of the pressurized silane gas. The outlet of the outlet buffer tank 207 is connected to the inlet of the pre-cooler 103 and is used to transport the pressurized silane gas to the pre-cooler 103. The reaction tower reflux tank 208 is connected to the liquid phase outlets of the first condenser 203, the second condenser 204 and the pre-cooler 103 and is used to collect the condensed liquid chlorosilane and reflux it to the silane reaction tower 201. The pressure pump 209 is connected to the reaction tower reflux tank 208 and is used to pressurize the reflux liquid and transport it back to the silane reaction tower 201.

[0043] Furthermore, the buffer tank 207 is used to balance the air flow output by the compressor 104, reduce pressure fluctuations, and ensure the stable operation of the pre-cooler 103. The outlet of the buffer tank 207 is connected to the inlet of the pre-cooler 103 to smoothly transport the pressurized silane gas to the pre-cooler 103. The stable air flow reduces the impact on the pre-cooler 103 and extends the service life of the equipment. At the same time, after the stable air flow enters the pre-cooler 103, it can cool the silane gas more evenly, thereby more effectively separating out liquid impurities and improving the separation efficiency of the subsequent separation tower.

[0044] The reaction tower reflux tank 208 is used to collect the condensed liquid chlorosilane and re-transport it back to the silane reaction tower 201 through the pressure pump 209 to achieve the recycling of materials. By recycling the liquid chlorosilane, the demand for fresh raw materials is reduced, the preheating energy consumption of the raw materials is lowered. The refluxed liquid chlorosilane already has a certain temperature before entering the silane reaction tower 201, reducing the heat demand of the reaction tower reboiler 202 and further reducing the energy consumption.

[0045] The setting of the pressure pump 209 ensures that the reflux liquid can smoothly enter the silane reaction tower 201 and maintains the pressure and liquid level stability in the silane reaction tower 201.

[0046] Refer to Figure 2 and Figure 4 As shown in, the purification unit 300 includes an adsorption column 301, a silane purification tower 302, a purification tower reboiler 303, a purification tower condenser 304, and a separation tower reboiler 305.

[0047] Among them, the adsorption column 301 is connected to the silane separation tower 101 and is used to adsorb and remove trace impurities in the silane gas. The trace impurities include boron and phosphorus. The silane purification tower 302 is used to further purify the silane gas by rectification to obtain a high-purity silane product. The inlet of the silane purification tower 302 is connected to the outlet of the adsorption column 301 and is used to receive the silane gas that has undergone adsorption treatment. The outlet of the silane purification tower 302 is used to output the high-purity silane product. The reboiler 303 of the purification tower is connected to the silane purification tower 302 and is used to provide heat for the silane purification tower 302 to maintain the operating temperature inside the tower. The condenser 304 of the purification tower is connected to the silane purification tower 302 and is used to condense the silane gas discharged from the top of the silane purification tower 302. The reboiler 305 of the separation tower is connected to the reboiler 202 of the reaction tower and the silane separation tower 101, and is used to receive the heat medium from the reboiler 202 of the reaction tower and use the heat medium to provide heat for the silane separation tower 101 to achieve the full utilization of waste heat.

[0048] Furthermore, the adsorption column 301 removes trace impurities in the silane gas, ensuring that the silane gas entering the rectification tower has a higher purity. Moreover, after removing the trace impurities, the corrosive impurities in the silane gas are reduced, extending the service life of the silane purification tower 302.

[0049] The silane purification tower 302 is used to further purify the silane gas by rectification to obtain a high-purity silane product. The inlet of the silane purification tower 302 is connected to the outlet of the adsorption column 301 to receive the silane gas that has undergone adsorption treatment. Through the rectification process, the impurities in the silane gas are further separated to ensure the purity of the final product.

[0050] The reboiler 303 of the purification tower promotes the rectification process inside the tower by heating the material at the bottom of the tower. The setting of the reboiler 303 of the purification tower reduces the temperature fluctuation and improves the stability of the rectification process.

[0051] The condenser 304 of the purification tower reduces the temperature of the gaseous silane to condense it into a liquid state, thereby realizing the collection of high-purity silane. The condensed liquid silane has a high purity, which is convenient for collection and storage.

[0052] The reboiler 305 of the separation tower ensures the separation effect inside the tower by heating the material at the bottom of the tower. The reboiler 305 of the separation tower is connected to the reboiler 202 of the reaction tower. After the heat medium used in the reboiler 202 of the reaction tower releases heat in the reboiler 202 of the reaction tower and undergoes pretreatment, it then enters the reboiler 305 of the separation tower to release heat, achieving the full utilization of waste heat. Through waste heat recovery, the loss of the heat medium is reduced and the operating cost is lowered.

[0053] Further, the impurities discharged from the bottom of the silane separation column 101 are refluxed to the silane reaction column 201 to achieve the recycling of materials. The impurities discharged from the bottom of the column are mainly unreacted raw materials such as trichlorosilane, dichlorosilane, and monochlorosilane, as well as other by-products. Refluxing these impurities to the reaction column allows them to participate in the reaction again, reducing the waste of raw materials.

[0054] Further, the adsorption column 301 is filled with an adsorbent, and the adsorbent includes but is not limited to activated carbon, molecular sieve, silica, resin, zeolite, or metal oxide, which is used to remove trace impurities in the silane gas. The adsorbent filled in the adsorption column 301 can be activated carbon or molecular sieve. The surface functional groups of activated carbon can combine with impurities such as boron and phosphorus through chemical adsorption, and the molecular sieve can selectively adsorb small molecule impurities that match the pore size, such as compounds of boron and phosphorus, through physical adsorption.

[0055] During use, trichlorosilane first enters the silane reaction column 201, where a disproportionation reaction occurs, generating substances such as silane, monochlorosilane, dichlorosilane, trichlorosilane, and tetrachlorosilane. The liquid-phase tetrachlorosilane is separated from the bottom of the silane reaction column 201. The gaseous substances such as silane, monochlorosilane, dichlorosilane, and trichlorosilane exit from the top of the column and are gradually condensed through the first condenser 203 and the second condenser 204 in sequence. In the first condenser 203, most of the dichlorosilane, trichlorosilane, and other substances are condensed into the liquid phase and enter the reaction column reflux tank 208 through the lower liquid pipeline of the first condenser 203. The uncondensed silane and monochlorosilane substances exit from the exhaust port of the first condenser 203 and enter the second condenser 204. In the first condenser 203, most of the monochlorosilane is condensed into the liquid phase and enters the reaction column reflux tank 208 through the lower liquid pipeline of the second condenser 204. The uncondensed silane is discharged after passing through the gas-liquid separation tank 205.

[0056] The silane discharged from the gas-liquid separation tank 205 enters the compressor 104. After being pressurized by the compressor 104, the gas-phase material mainly composed of silane is discharged into the outlet buffer tank 207. The gas-phase material exiting from the top of the outlet buffer tank 207 enters the silane separation tower 101 for further separation after passing through the pre-cooler 103. Materials such as dichlorosilane and trichlorosilane in the reaction tower reflux tank 208 are pressurized by the pressure pump 209 and then refluxed into the silane reaction tower 201 for re-reaction. In the silane separation tower 101, silane and a small amount of materials such as hydrogen chloride silane entrained are separated. Hydrogen chloride silane is discharged from the bottom of the silane separation tower 101 and returns to the silane reaction tower 201 for reaction. Silane and a small amount of hydrogen, nitrogen and other hydrogen components entrained are taken out from the top of the silane separation 101 and enter the separation tower condenser 102. After heat exchange, silane is condensed into a liquid phase and refluxed back into the silane separation tower 101. A small amount of uncondensed hydrogen and nitrogen are discharged from the exhaust port of the separation tower condenser 102. High-purity silane is taken out from the side of the silane separation tower 101.

[0057] The high-purity silane taken out from the side of the silane separation tower 101 enters the adsorption column 301, where trace impurities such as boron and phosphorus in the high-purity silane are removed. The silane after adsorption and impurity removal then enters the silane purification tower 302 for rectification, and high-quality silane is taken out from the side of the silane purification tower 302.

[0058] Refer to Figure 5 , and the recycling of the refrigerant will be described next.

[0059] The circulation unit 400 includes a chilled water device 401 and chilled water pipelines. The "refrigerant" (at this time, the "refrigerant" is water after heat exchange, and its temperature must be higher than the temperature of the refrigerant required by the silane production and purification unit) that returns to the chilled water device 401 after heat exchange, as well as the water supplemented from the outside into the chilled water device 401, are all refrigerated by the chilled water device 401 and then distributed to each chilled water pipeline for recycling.

[0060] In this embodiment, specifically: the chilled water device 401 includes a chilled water tank, a refrigeration unit, a chilled water pump and an internal circulation chilled water pipeline. The chilled water tank is provided with a water replenishment end, a return water end, a water inlet end and a liquid level gauge. The outside water enters the chilled water tank through the water replenishment end, and then passes through the internal circulation chilled water pipeline and is refrigerated by the refrigeration unit to obtain the refrigerant, which then enters the chilled water tank through the water inlet end, and the refrigerant is distributed to the first chilled water pipeline 402 and the second chilled water pipeline 403.

[0061] The chilled water equipment 401 distributes the refrigerant to the first chilled water pipeline 402 and the second chilled water pipeline 403. Among them, the refrigerant in the second chilled water pipeline 403 flows out through the third chilled water pipeline 404 after heat exchange in the separation tower condenser 102, and the refrigerant in the first chilled water pipeline 402 flows out through the fourth chilled water pipeline 405 after heat exchange in the purification tower condenser 304.

[0062] In this embodiment, the liquefaction temperature of silane is -98°C. Under standard atmospheric pressure, silane will change from gaseous state to liquid state at this temperature. Therefore, the refrigerant temperature required by the separation tower condenser 102 and the purification tower condenser 304 needs to be lower than -98°C. Therefore, the temperature range of the refrigerant in the first chilled water pipeline 402 and the second chilled water pipeline 403 is between -120°C and -98°C. After the refrigerant in the first chilled water pipeline 402 and the second chilled water pipeline 403 exchanges heat with the silane gas entering the separation tower condenser 102 and the second chilled water pipeline 403, the refrigerant temperature rises.

[0063] By calculating through the heat transfer equation, the temperature of the refrigerant after heat exchange in the separation tower condenser 102 and the second chilled water pipeline 403 can be obtained. The heat transfer equation is as follows: ; where Q is the heat transfer rate, U is the heat transfer coefficient, A is the heat transfer area, and ΔT is the temperature difference between the refrigerant and silane.

[0064] The third chilled water pipeline 404 and the fourth chilled water pipeline 405 distribute the refrigerant to the fifth chilled water pipeline 406 and the sixth chilled water pipeline 407 respectively. Among them, the refrigerant in the fifth chilled water pipeline 406 flows out through the seventh chilled water pipeline 408 after heat exchange in the second condenser 204, and the refrigerant in the sixth chilled water pipeline 407 flows out through the eighth chilled water pipeline 409 after heat exchange in the first condenser 203.

[0065] The temperature range of the refrigerant in the first chilled water pipeline 402 and the second chilled water pipeline 403 is -120°C to -98°C. After heat exchange in the separation tower condenser 102 and the purification tower condenser 304, the refrigerant temperature will rise, but it still needs to be low enough to meet the condensation requirements of the first condenser 203 and the second condenser 204. The main tasks of the first condenser 203 and the second condenser 204 are to condense the gaseous products. Therefore, the refrigerant temperature needs to be lower than the boiling point of the gaseous products to achieve effective condensation.

[0066] Among them, the substances mainly condensed by the first condenser 203 are dichlorosilane and trichlorosilane. The boiling point of dichlorosilane is about 29°C, and the boiling point of trichlorosilane is about 54°C. In order to condense these substances, the refrigerant temperature needs to be lower than 29°C, that is, the boiling point of dichlorosilane. Usually, the refrigerant temperature is 10°C to 20°C lower than the boiling point. Therefore, the refrigerant temperature of the first condenser 203 can be controlled below 10°C.

[0067] Among them, the substances mainly condensed by the second condenser 204 are monochlorosilane. The boiling point of monochlorosilane is about -13°C. In order to condense monochlorosilane, the refrigerant temperature needs to be lower than -13°C, that is, the boiling point of monochlorosilane. Usually, the refrigerant temperature is 10°C to 20°C lower than the boiling point. Therefore, the refrigerant temperature of the second condenser 204 can be controlled below -20°C.

[0068] After the heat exchange of the separation tower condenser 102 and the purification tower condenser 304, the refrigerant temperature will increase, but it can still meet the condensation requirements of the first condenser 203 and the second condenser 204.

[0069] The seventh chilled water pipeline 408 and the eighth chilled water pipeline 409 distribute the refrigerant to the ninth chilled water pipeline 410. Among them, the refrigerant in the ninth chilled water pipeline 410 undergoes heat exchange through the pre-cooler 103 and then flows out through the tenth chilled water pipeline 411 and returns to the chilled water equipment 401 for recycling.

[0070] The hot medium produced by the pre-cooler 103 can also be first provided to the purification tower reboiler 303 for use, providing heat for the purification tower reboiler 303. At the same time, the purification tower reboiler 303 preliminarily cools the hot medium produced by the pre-cooler 103, and then outputs the hot medium after heat exchange through the purification tower reboiler 303 to the chilled water equipment 401, reducing the cooling pressure of the chilled water equipment 401.

[0071] The pre-cooler 103 uses the refrigerant from the ninth chilled water pipeline 410 to cool the silane material. Since the refrigerant in the ninth chilled water pipeline 410 has undergone heat exchange through the first condenser 203 and the second condenser 204, the maximum temperature of the refrigerant in the ninth chilled water pipeline 410 may be higher than -20°C. However, by adjusting the pressure, the boiling point of monochlorosilane is increased. Therefore, the refrigerant in the ninth chilled water pipeline 410 can meet the condensation requirements of the pre-cooler 103, thereby pre-separating monochlorosilane.

[0072] The precooler 103 uses the refrigerant in the ninth chilled water pipeline 410 to lower the temperature of silane. It not only precools silane but also condenses a part of trichlorosilane in the material mainly composed of silane into the liquid phase, realizing the preliminary separation of silane and trichlorosilane. Since the boiling point of trichlorosilane is higher than that of silane, part of the trichlorosilane will condense into a liquid state, while the silane gas remains in a gaseous state. The condensed liquid trichlorosilane can be separated through a pipeline, and the uncondensed silane gas continues to enter the silane separation tower 101. After precooling treatment, the impurity content in the silane gas entering the silane separation tower 101 decreases, reducing the separation load of the silane separation tower 101 and improving the separation efficiency.

[0073] Among them, the main substance condensed by the precooler 103 is trichlorosilane. The boiling point of trichlorosilane is about -13°C. Due to the setting of the compressor 104, the boiling point of trichlorosilane will be significantly higher than the boiling point under normal pressure. The relationship between the boiling point and pressure can be determined by the Antoine equation. The Antoine equation is an empirical formula used to describe the relationship between the vapor pressure and temperature of a pure substance. In the present invention, the Antoine equation is used to illustrate the relationship between the boiling point and pressure of trichlorosilane. The Antoine equation is as follows: ; where P is the pressure, T is the temperature, and A, B, and C are the Antoine constants of the substance.

[0074] Table 1 shows the boiling points of silane and trichlorosilane under different atmospheric pressures, and also illustrates the boiling point differences and separation efficiencies of silane and trichlorosilane under different atmospheric pressures.

[0075] Table 1 Boiling Points of Silane and Trichlorosilane under Different Atmospheric Pressures

[0076] Among them, according to the temperature of the refrigerant in the ninth chilled water pipeline 410, the precooler 103 can be pressurized to separate trichlorosilane while precooling silane, that is, the boiling point of silane is lower than the temperature of the refrigerant in the ninth chilled water pipeline 410, and at the same time, the boiling point of trichlorosilane is higher than the temperature of the refrigerant in the ninth chilled water pipeline 410. For example, when the temperature of the refrigerant is 10°C, the compressor 104 is started to make the pressure in the precooler 103 at 4 atmospheres. At this time, the boiling point of trichlorosilane is 15°C, and the temperature of the refrigerant can just condense trichlorosilane.

[0077] By monitoring the temperature of the refrigerant in the ninth chilled water pipeline 410, the horsepower of the compressor 104 is dynamically adjusted to maintain the best separation effect and achieve the lowest energy consumption. A temperature sensor is set in the ninth chilled water pipeline 410 to monitor the temperature of the refrigerant in real time. According to the temperature of the refrigerant, the horsepower of the compressor 104 is dynamically adjusted through the control system.

[0078] The corresponding relationship between the refrigerant temperature in the ninth chilled water pipeline 410 and the pressure in the pre-cooler 103 is described through Table 2.

[0079] Table 2 Pressures in the pre-cooler corresponding to different refrigerant temperatures

[0080] Among them, the pressure is the output pressure of the compressor 104. The atmospheric pressure value is convenient for practical applications. The refrigerant temperature is the temperature of the refrigerant in the ninth chilled water pipeline 410. The boiling point of trichlorosilane is the boiling point under the corresponding pressure. The boiling point of silane is the boiling point under the corresponding pressure. The compressor horsepower is the horsepower of the compressor 104 under the corresponding pressure.

[0081] A high-precision temperature sensor is installed in the ninth chilled water pipeline 410 to monitor the temperature of the refrigerant in real time. The dynamic adjustment of the horsepower of the compressor 104 is realized through a PLC (Programmable Logic Controller) or a DCS (Distributed Control System). If the refrigerant temperature is higher than the boiling point of trichlorosilane, increase the horsepower of the compressor 104 to increase the pressure and raise the boiling point of trichlorosilane. Assume that the refrigerant temperature is 20 °C. According to the table, the corresponding pressure is 0.5 MPa. At this time, the boiling point of silane is -74 °C, and the boiling point of trichlorosilane is 21 °C. By adjusting the horsepower of the compressor, it can be ensured that the refrigerant temperature is lower than the boiling point of trichlorosilane, thereby achieving the best separation effect and the lowest energy consumption. To increase the condensation effect, the pressure can be increased to 0.6 MPa, thereby increasing the temperature difference between the refrigerant temperature and the boiling point of trichlorosilane.

[0082] Finally, it should be pointed out that the methods and devices described in detail above are only examples, and those skilled in the art can modify these examples in different ways as long as they do not depart from the scope of the present invention.

Claims

1. An energy-saving silane production and purification system, characterized in that: including, a separation unit (100) including a silane separation column (101) for deeply separating the preliminarily treated silane gas from other impurities, which include but are not limited to trichlorosilane, dichlorosilane, hydrogen, and nitrogen, to improve the purity of silane; a separation column condenser (102) for condensing the silane gas discharged from the top of the silane separation column (101) to achieve liquefaction of silane and separation of impurities; a pre-cooler (103) for pre-cooling the silane gas before the silane separation column (101) to reduce the temperature of the silane gas and achieve condensation of some impurities; the pre-cooler (103) is connected to the separation column condenser (102) and is used to receive the refrigerant from the separation column condenser (102) and pre-cool the silane gas using the refrigerant; a compressor (104) for pressurizing the silane gas before the pre-cooler (103) to increase the pressure of the silane gas.

2. The energy-saving silane production and purification system according to claim 1, characterized in that: It also includes, a production unit (200) for converting trichlorosilane into silane gas and chlorosilane compounds and performing a preliminary separation treatment on the silane gas and chlorosilane compounds; a purification unit (300) for removing trace impurities from the silane gas and further purifying the silane gas by rectification; a circulation unit (400) for recycling the refrigerant.

3. The energy-saving silane production and purification system according to claim 2, wherein: The production unit (200) includes, a silane reaction tower (201) for converting trichlorosilane into silane gas and other chlorosilane compounds; a reaction tower reboiler (202) connected to the silane reaction tower (201) for providing heat to the silane reaction tower (201) to maintain the temperature required for the reaction; a first condenser (203) connected to the silane reaction tower (201) for condensing some of the chlorosilane compounds discharged from the top of the silane reaction tower (201); a second condenser (204) connected to the first condenser (203) for further condensing the uncondensed silane gas and other chlorosilane compounds; a gas-liquid separation tank (205) connected to the second condenser (204) for separating the condensed liquid substance and the uncondensed gaseous silane; the outlet of the gas-liquid separation tank (205) is connected to the inlet of the compressor (104) and is used to transport the separated gaseous silane to the compressor (104).

4. The energy-saving silane production and purification system according to claim 2 or 3, characterized in that: The production unit (200) further includes, an outlet buffer tank (207) connected to the outlet of the compressor (104) for stabilizing the pressure of the pressurized silane gas; the outlet of the outlet buffer tank (207) is connected to the inlet of the pre-cooler (103) and is used to transport the pressurized silane gas to the pre-cooler (103).

5. The energy-saving silane production and purification system according to claim 3, characterized in that: The production unit (200) further includes, a reaction tower reflux tank (208) connected to the liquid phase outlets of the first condenser (203), the second condenser (204), and the pre-cooler (103) for collecting the condensed liquid chlorosilane and refluxing it to the silane reaction tower (201); a pressure pump (209) connected to the reaction tower reflux tank (208) for pressurizing the reflux liquid and transporting it back to the silane reaction tower (201).

6. The energy-saving silane production and purification system according to claim 3 or 5, characterized in that: The impurities discharged from the bottom of the silane separation column (101) are refluxed to the silane reaction column (201) to achieve the recycling of materials.

7. The energy-saving silane production and purification system according to any one of claims 2, 3 or 5, characterized in that: The purification unit (300) includes an adsorption column (301) connected to the silane separation column (101) for adsorbing and removing trace impurities in the silane gas, and the trace impurities include boron and phosphorus; a silane purification column (302) for further purifying the silane gas by rectification to obtain a high-purity silane product; The inlet of the silane purification column (302) is connected to the outlet of the adsorption column (301) and is used to receive the silane gas treated by adsorption; The outlet of the silane purification column (302) is used to output a high-purity silane product.

8. The energy-saving silane production and purification system according to claim 7, wherein: The purification unit (300) further includes a purification column reboiler (303) connected to the silane purification column (302) for providing heat to the silane purification column (302) to maintain the operating temperature inside the column; a purification column condenser (304) connected to the silane purification column (302) for condensing the silane gas discharged from the top of the silane purification column (302).

9. The energy-saving silane production and purification system according to claim 3 or 5, characterized in that: The purification unit (300) further includes a separation column reboiler (305) connected to the reaction column reboiler (202) and the silane separation column (101) for receiving the heat medium from the reaction column reboiler (202) and using the heat medium to provide heat to the silane separation column (101) to achieve the full utilization of waste heat.

10. The energy-saving silane production and purification system according to claim 7, wherein: The adsorption column (301) is filled with an adsorbent, and the adsorbent includes but is not limited to activated carbon, molecular sieve, silica, resin, zeolite or metal oxide, for removing trace impurities in the silane gas.

11. The energy-saving silane production and purification system according to claim 8 or 10, characterized in that: The circulation unit (400) includes a chilled water device (401) and chilled water pipelines. The chilled water device (401) distributes the refrigerant to a first chilled water pipeline (402) and a second chilled water pipeline (403). Among them, the refrigerant in the second chilled water pipeline (403) flows out through a third chilled water pipeline (404) after heat exchange through the separation column condenser (102), and the refrigerant in the first chilled water pipeline (402) flows out through a fourth chilled water pipeline (405) after heat exchange through the purification column condenser (304).

12. The energy-saving silane production and purification system according to claim 11, wherein: The third chilled water pipeline (404) and the fourth chilled water pipeline (405) distribute the refrigerant to a fifth chilled water pipeline (406) and a sixth chilled water pipeline (407) respectively. Among them, the refrigerant in the fifth chilled water pipeline (406) flows out through a seventh chilled water pipeline (408) after heat exchange through the second condenser (204), and the refrigerant in the sixth chilled water pipeline (407) flows out through an eighth chilled water pipeline (409) after heat exchange through the first condenser (203).

13. The energy-saving silane production and purification system according to claim 12, characterized in that: The seventh chilled water pipeline (408) and the eighth chilled water pipeline (409) distribute the refrigerant to a ninth chilled water pipeline (410). Among them, the refrigerant in the ninth chilled water pipeline (410) flows out through a tenth chilled water pipeline (411) after heat exchange through the pre-cooler (103) and returns to the chilled water device (401) for recycling.

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