System and method for hydrolyzing organochlorosilane and refining hydrochloric acid
阅读说明：本技术 一种有机氯硅烷水解和盐酸精制系统及方法 (System and method for hydrolyzing organochlorosilane and refining hydrochloric acid ) 是由 李全 李升大 王宇光 谷新春 李国华 袁小建 彭永红 厉相 陶小钰 李阳 何欣蔚 于 2019-10-15 设计创作，主要内容包括：本发明公开了一种有机氯硅烷水解和盐酸精制系统及方法,特点是包括水解塔、一级相分离器、二级相分离器、第一盐酸净化塔、减压罐、第二盐酸净化塔、第一萃取塔、第二萃取塔、汽提塔和线环分离塔,水解塔的侧部设置有多段进料口,水解塔的上端油相出口与一级相分离器的进料口连接,一级相分离器的油相出口与二级相分离器的进料口连接,水解塔的顶部气相出口、一级相分离器的气相出口和二级相分离器的气相出口分别连接第一冷凝器,第一冷凝器的顶部气相出口与第一盐酸净化塔的下端进料口连接,第一盐酸净化塔的上端设置有新鲜盐酸溶液进口,第一盐酸净化塔的底部油相出口,优点是反应转化效率高且产品纯度高。(The invention discloses an organochlorosilane hydrolysis and hydrochloric acid refining system and a method, which are characterized by comprising a hydrolysis tower, a primary phase separator, a secondary phase separator, a first hydrochloric acid purification tower, a pressure reduction tank, a second hydrochloric acid purification tower, a first extraction tower, a second extraction tower, a stripping tower and a wire loop separation tower, wherein the side part of the hydrolysis tower is provided with a multi-section feed inlet, an upper oil phase outlet of the hydrolysis tower is connected with the feed inlet of the primary phase separator, an oil phase outlet of the primary phase separator is connected with the feed inlet of the secondary phase separator, a top gas phase outlet of the hydrolysis tower, a gas phase outlet of the primary phase separator and a gas phase outlet of the secondary phase separator are respectively connected with a first condenser, a top gas phase outlet of the first condenser is connected with a lower end feed inlet of the first hydrochloric acid purification tower, the upper end of the first hydrochloric acid purification tower is provided with a fresh hydrochloric acid solution inlet, its advantages are high conversion efficiency and high purity of product.)
1. An organochlorosilane hydrolyzation and hydrochloric acid refining system is characterized in that: the device comprises a hydrolysis tower, a primary phase separator, a secondary phase separator, a first hydrochloric acid purification tower, a pressure reduction tank, a second hydrochloric acid purification tower, a first extraction tower, a second extraction tower, a stripping tower and a wire ring separation tower, wherein a plurality of sections of feed inlets are formed in the lateral part of the hydrolysis tower, an oil phase outlet at the upper end of the hydrolysis tower is connected with the feed inlet of the primary phase separator, an oil phase outlet of the primary phase separator is connected with the feed inlet of the secondary phase separator, a gas phase outlet at the top of the hydrolysis tower, a gas phase outlet of the primary phase separator and a gas phase outlet of the secondary phase separator are respectively connected with a first condenser, a gas phase outlet at the top of the first condenser is connected with a feed inlet at the lower end of the first hydrochloric acid purification tower, a fresh hydrochloric acid solution inlet is formed in the upper end of the first hydrochloric acid purification tower, an oil phase outlet at the bottom of the first hydrochloric acid purification, The water phase outlet of the first-stage phase separator and the water phase outlet of the second-stage phase separator are respectively connected with a first circulating pump, the first circulating pump is connected with the bottom feed inlet of the hydrolysis tower through a heat exchanger, and the bottom oil phase outlet of the first hydrochloric acid purification tower is connected with the fresh hydrochloric acid solution inlet of the first hydrochloric acid purification tower through a second circulating pump; the top gas phase outlet of the first hydrochloric acid purification tower is connected with an external chloromethane synthesis device through a hydrochloric acid oil remover, the oil phase outlet of the secondary phase separator is connected with the side feed inlet of the pressure reduction tank, the top gas phase outlet of the pressure reduction tank is connected with the feed inlet of the second hydrochloric acid purification tower, and the top gas phase outlet of the second hydrochloric acid purification tower is connected with the external chloromethane synthesis device through a hydrochloric acid compressor; the bottom oil phase export of decompression jar with the lower part feed inlet of first extraction tower connect, the upper portion discharge gate of first extraction tower with the lower part feed inlet of second extraction tower connect, the upper portion discharge gate of second extraction tower with the lower part feed inlet of strip tower connect, the lower part discharge gate of strip tower with the wire loop knockout tower connect.
2. The organochlorosilane hydrolysis and hydrochloric acid purification system according to claim 1, wherein: a vaporizer is arranged at a multi-section feed inlet of the hydrolysis tower; the bottom liquid phase outlet of the first condenser is connected with the feed inlet of the secondary phase separator; the bottom material outlet of the first extraction tower is connected with the first circulating pump, and the bottom material outlet of the second extraction tower is connected with the upper circulating material inlet of the first extraction tower; and a gas phase outlet at the top of the stripping tower is connected with the first circulating pump through a second condenser.
3. The organochlorosilane hydrolysis and hydrochloric acid purification system according to claim 1, wherein: a plurality of layers of tower plates are arranged in the hydrolysis tower, and a heating coil is arranged between the adjacent tower plates.
4. A method for hydrolyzing organochlorosilane and refining hydrochloric acid using the organochlorosilane hydrolysis and hydrochloric acid refining system of claim 1, comprising the steps of:
(1) vaporizing pressurized liquid-phase dimethyldichlorosilane with the pressure of 0-0.5MPaG by a vaporizer or heating the liquid-phase dimethyldichlorosilane by a heat exchanger, feeding the vaporized liquid-phase dimethyldichlorosilane into a hydrolysis tower in sections for hydrolysis reaction, controlling the reaction temperature in the hydrolysis tower to be 20-60 ℃ and the pressure to be 0-0.5MPaG, feeding a gas phase obtained by the reaction into a first condenser, and feeding an oil phase obtained by the reaction into a first-stage phase separator;
(2) controlling the pressure of the primary phase separator to be equal to that of the hydrolysis tower to carry out oil-water-gas three-phase separation, sending the water phase obtained by separation back to the hydrolysis tower for recycling, sending the gas phase obtained by separation into a first condenser, and sending the oil phase obtained by separation into a secondary phase separator;
(3) controlling the pressure of the secondary phase separator to carry out oil-water-gas three-phase separation under the same pressure of the hydrolysis tower, sending the water phase obtained by separation back to the hydrolysis tower for recycling, sending the oil phase obtained by separation into a decompression tank, sending the gas phase obtained by separation into a first condenser, sending the gas phase obtained by condensation of the first condenser into a first hydrochloric acid purification tower, and sending the oil phase obtained by condensation of the first condenser back to the secondary phase separator for recycling;
(4) controlling the pressure in the pressure reduction tank to be micro-positive pressure, feeding the separated gas phase into a second hydrochloric acid purification tower, and feeding the separated liquid phase into a first extraction tower;
(5) intermittently feeding fresh dilute hydrochloric acid into a first hydrochloric acid purification tower, controlling the temperature in the first hydrochloric acid purification tower to be-10-0 ℃ and the pressure to be 0-0.5MPaG, feeding HCl gas with the volume fraction of 99.5% obtained by separation into an external chloromethane removal synthesis device after passing through a hydrochloric acid oil remover, feeding part of the oil phase obtained by separation back to a hydrolysis tower for recycling, and mixing the other part of the oil phase with the fresh dilute hydrochloric acid and returning the mixture to the first hydrochloric acid purification tower for recycling;
(6) controlling the temperature of the second hydrochloric acid purification tower to be 20-60 ℃, and conveying the HCl gas with the volume fraction of 99.5% obtained by separation into an external chloromethane removal synthesis device after the HCl gas is pressurized by a hydrochloric acid compressor;
(7) controlling the temperature of the first extraction tower to be 70-95 ℃, removing hydrochloric acid, sending the upper-layer liquid obtained by separation into a second extraction tower, and sending the lower-layer liquid obtained by separation back into the hydrolysis tower for recycling;
(8) feeding pure water into the upper part of a second extraction tower, controlling the temperature of the second extraction tower to be 70-95 ℃, removing hydrochloric acid, feeding the upper-layer liquid obtained by separation into a stripping tower, and feeding the lower-layer liquid obtained by separation back to the first extraction tower for recycling;
(9) controlling the temperature of the stripping tower at 70-150 ℃ and the pressure at-0.1 MPaG to 0.1MPaG, sending the gas phase obtained by separation back to the hydrolysis tower through a second condenser for recycling, and sending the polysiloxane oil phase with Cl < - > less than or equal to 3ppm obtained by separation into a wire loop separation tower for separating the wire body and the ring body.
5. The method of claim 4, wherein the organochlorosilane is hydrolyzed and purified with hydrochloric acid, said method comprising the steps of: the dimethyl dichlorosilane in the hydrolysis tower adopts gas-phase multi-section feeding, and the feeding amount of the dimethyl dichlorosilane in each section is 40-90%, 40-5% and 20-5%.
Technical Field
The invention relates to a system and a method for hydrolyzing organochlorosilane and refining hydrochloric acid.
Background
In the production process of organic silicon, dimethyl dichlorosilane is subjected to a series of hydrolysis reactions in a reactor to obtain organic siloxane, which is an important link in the production flow of organic silicon. The quality of the process level in the link is directly related to the quality of the organic silicon product and the recovery efficiency of chlorine in the production raw materials, and the excellent hydrolysis scheme can effectively reduce the production cost of the organic silicon product.
According to the traditional process, after dimethyl dichlorosilane is subjected to pressurized hydrolysis reaction, the obtained product mainly comprises polysiloxane (hydrolysate) and concentrated hydrochloric acid, the hydrolysis feeding mode is that liquid-phase dimethyl dichlorosilane and hydrochloric acid are mixed to obtain hydrolysate siloxane, the hydrolysate carries a small amount of concentrated hydrochloric acid to flow out of the upper part of a hydrolysis tower, and the hydrolysate with high purity is obtained after separation by a phase separator. And recycling a water phase part obtained after phase separation to the hydrolysis reactor for reuse, and enabling a part of the water phase part to enter a subsequent HCl washing and absorbing section. Conveying the high-purity hydrolysate to a hydrochloric acid analysis tower through an intermediate tank by a pump, reducing the pressure to normal pressure, and conveying the hydrolysate further subjected to HCl removal to an acid washing section for continuous hydrochloric acid removal. The hydrolysis reaction, the phase separation and the hydrochloric acid analysis tower generate gas-phase HCl, and after the gas-phase HCl is collected uniformly, part of the gas-phase HCl is sent to an HCl washing tower to obtain high-purity gas-phase HCl which is returned to the chloromethane synthesis section; and one part of the hydrochloric acid solution is sent to an HCl absorption tower to obtain a liquid-phase hydrochloric acid solution with lower utilization value. However, in the HCl analysis process, part of the light oil phase is brought out and comes to the HCl water washing tower and the HCl absorption tower along with the HCl gas, so that corresponding equipment and pipeline blockage can be caused as long as time passes, the parking maintenance frequency is increased, the siloxane yield is reduced, and the driving period is shortened. Furthermore, the siloxane contained in the HCl gas can also affect the methyl chloride synthesis process. Therefore, the problems of improving the technological process of a hydrolysis reaction system, reducing the siloxane content in the hydrolysis acid and the like need to be solved urgently.
Disclosure of Invention
The invention aims to provide a system and a method for hydrolyzing organochlorosilane and refining hydrochloric acid, which have high reaction conversion efficiency and high product purity.
The technical scheme adopted by the invention for solving the technical problems is as follows: an organochlorosilane hydrolysis and hydrochloric acid refining system comprises a hydrolysis tower, a primary phase separator, a secondary phase separator, a first hydrochloric acid purification tower, a decompression tank, a second hydrochloric acid purification tower, a first extraction tower, a second extraction tower, a stripping tower and a wire loop separation tower, wherein a multi-section feed inlet is formed in the side part of the hydrolysis tower, an oil phase outlet at the upper end of the hydrolysis tower is connected with the feed inlet of the primary phase separator, an oil phase outlet of the primary phase separator is connected with the feed inlet of the secondary phase separator, a gas phase outlet at the top of the hydrolysis tower, a gas phase outlet of the primary phase separator and a gas phase outlet of the secondary phase separator are respectively connected with a first condenser, a gas phase outlet at the top of the first condenser is connected with the feed inlet at the lower end of the first hydrochloric acid purification tower, and a fresh hydrochloric acid solution inlet is formed in the upper end of the first hydrochloric acid purification tower, the bottom oil phase outlet of the first hydrochloric acid purification tower, the water phase outlet of the first-stage phase separator and the water phase outlet of the second-stage phase separator are respectively connected with a first circulating pump, the first circulating pump is connected with the bottom feed inlet of the hydrolysis tower through a heat exchanger, and the bottom oil phase outlet of the first hydrochloric acid purification tower is connected with the fresh hydrochloric acid solution inlet of the first hydrochloric acid purification tower through a second circulating pump; the top gas phase outlet of the first hydrochloric acid purification tower is connected with an external chloromethane synthesis device through a hydrochloric acid oil remover, the oil phase outlet of the secondary phase separator is connected with the side feed inlet of the pressure reduction tank, the top gas phase outlet of the pressure reduction tank is connected with the feed inlet of the second hydrochloric acid purification tower, and the top gas phase outlet of the second hydrochloric acid purification tower is connected with the external chloromethane synthesis device through a hydrochloric acid compressor; the bottom oil phase export of decompression jar with the lower part feed inlet of first extraction tower connect, the upper portion discharge gate of first extraction tower with the lower part feed inlet of second extraction tower connect, the upper portion discharge gate of second extraction tower with the lower part feed inlet of strip tower connect, the lower part discharge gate of strip tower with the wire loop knockout tower connect.
A vaporizer is arranged at a multi-section feed inlet of the hydrolysis tower; the bottom liquid phase outlet of the first condenser is connected with the feed inlet of the secondary phase separator; the bottom material outlet of the first extraction tower is connected with the first circulating pump, and the bottom material outlet of the second extraction tower is connected with the upper circulating material inlet of the first extraction tower; and a gas phase outlet at the top of the stripping tower is connected with the first circulating pump through a second condenser.
A plurality of layers of tower plates are arranged in the hydrolysis tower, and a heating coil is arranged between the adjacent tower plates. The segmented feeding effect is realized by the arrangement of multiple layers of tower plates, and raw materials are heated between each layer by the heating coil.
An organochlorosilane hydrolysis and hydrochloric acid refining method comprises the following steps:
(1) vaporizing pressurized liquid-phase dimethyldichlorosilane with the pressure of 0-0.5MPaG by a vaporizer or heating the liquid-phase dimethyldichlorosilane by a heat exchanger, feeding the vaporized liquid-phase dimethyldichlorosilane into a hydrolysis tower in sections for hydrolysis reaction, controlling the reaction temperature in the hydrolysis tower to be 20-60 ℃ and the pressure to be 0-0.5MPaG, feeding a gas phase obtained by the reaction into a first condenser, and feeding an oil phase obtained by the reaction into a first-stage phase separator;
(2) controlling the pressure of the primary phase separator to be equal to that of the hydrolysis tower to carry out oil-water-gas three-phase separation, sending the water phase obtained by separation back to the hydrolysis tower for recycling, sending the gas phase obtained by separation into a first condenser, and sending the oil phase obtained by separation into a secondary phase separator;
(3) controlling the pressure of the secondary phase separator to carry out oil-water-gas three-phase separation under the same pressure of the hydrolysis tower, sending the water phase obtained by separation back to the hydrolysis tower for recycling, sending the oil phase obtained by separation into a decompression tank, sending the gas phase obtained by separation into a first condenser, sending the gas phase obtained by condensation of the first condenser into a first hydrochloric acid purification tower, and sending the oil phase obtained by condensation of the first condenser back to the secondary phase separator for recycling;
(4) controlling the pressure in the pressure reduction tank to be micro-positive pressure, feeding the separated gas phase into a second hydrochloric acid purification tower, and feeding the separated liquid phase into a first extraction tower;
(5) intermittently feeding fresh dilute hydrochloric acid into a first hydrochloric acid purification tower, controlling the temperature in the first hydrochloric acid purification tower to be-10-0 ℃ and the pressure to be 0-0.5MPaG, feeding HCl gas with the volume fraction of 99.5% obtained by separation into an external chloromethane removal synthesis device after passing through a hydrochloric acid oil remover, feeding part of the oil phase obtained by separation back to a hydrolysis tower for recycling, and mixing the other part of the oil phase with the fresh dilute hydrochloric acid and returning the mixture to the first hydrochloric acid purification tower for recycling;
(6) controlling the temperature of the second hydrochloric acid purification tower to be 20-60 ℃, and conveying the HCl gas with the volume fraction of 99.5% obtained by separation into an external chloromethane removal synthesis device after the HCl gas is pressurized by a hydrochloric acid compressor;
(7) controlling the temperature of the first extraction tower to be 70-95 ℃, removing hydrochloric acid, sending the upper-layer liquid obtained by separation into a second extraction tower, and sending the lower-layer liquid obtained by separation back into the hydrolysis tower for recycling;
(8) feeding pure water into the upper part of a second extraction tower, controlling the temperature of the second extraction tower to be 70-95 ℃, removing hydrochloric acid, feeding the upper-layer liquid obtained by separation into a stripping tower, and feeding the lower-layer liquid obtained by separation back to the first extraction tower for recycling;
(9) controlling the temperature of the stripping tower at 70-150 ℃ and the pressure at-0.1 MPaG to 0.1MPaG, sending the gas phase obtained by separation back to the hydrolysis tower through a second condenser for recycling, and sending the polysiloxane oil phase with Cl < - > less than or equal to 3ppm obtained by separation into a wire loop separation tower for separating the wire body and the ring body.
The dimethyl dichlorosilane in the hydrolysis tower adopts gas phase multi-section feeding, and the feeding amount of the dimethyl dichlorosilane in each section is 40-90%, 40-5% and 20-5%.
Compared with the prior art, the invention has the advantages that: the invention relates to a system and a method for hydrolyzing organochlorosilane and refining hydrochloric acid, wherein pressurized (0-0.5 MPaG) liquid-phase dimethyldichlorosilane is vaporized by a vaporizer and then is dispersed and introduced into a pressurized hydrolysis tower for hydrolysis reaction to generate a siloxane oil phase and HCl gas. If the vaporizer is not used for heating, the liquid-phase dimethyldichlorosilane can also enter the hydrolysis tower after being heated by the heat exchanger, and the two feeding modes can be switched according to actual requirements. The oil phase generated by hydrolysis carries partial hydrochloric acid to enter a primary phase separator and a secondary phase separator through an overflow port at the upper part of the hydrolysis tower, and oil-water separation is carried out under the same pressure with the hydrolysis tower. In the hydrolysis reaction and the oil-water separation process, 0-0.5MPaG HCl gas can be generated, the HCl gas is uniformly collected and then cooled by a condenser, and then enters an HCl purification tower 1 to remove an oil phase carried by the HCl gas, and the operation is carried out under the same pressure. And deoiling the deoiled HCl gas again through an oil remover, and conveying the deoiled HCl gas to a methyl chloride synthesis device. The oil phase cooled down by the condenser returns to the secondary phase separator for oil-water separation again. The liquid phase feeding at the upper part of the HCl purification tower is fresh dilute hydrochloric acid fed intermittently, after siloxane in a gas phase is removed, one part of the fresh dilute hydrochloric acid flows out of the tower bottom, and is circulated back to the hydrolysis tower to participate in hydrolysis reaction after being mixed and heated with oil phases flowing out of the bottoms of the primary phase separator and the secondary phase separator; and returning part of the HCl solution to the top of the HCl purification tower for recycling. And the oil phase flows out from the top of the secondary phase separator, enters a pressure reduction tank, is reduced to normal pressure or micro positive pressure, and simultaneously separates out HCl gas. The HCl gas separated out from the decompression tank is deoiled and dried by an
1. the first HCl purification tower adopts fresh hydrochloric acid to wash HCl gas (31% normal pressure saturated hydrochloric acid), so that impurities are removed more fully. The fresh hydrochloric acid does not contain siloxane impurities, and more siloxane impurities can be taken away by the hydrochloric acid and flow out of the tower bottom in the process of washing the hydrochloric acid gas in the tower;
2. the HCl gas is washed by fresh hydrochloric acid, so that the content of hydrolysate in the HCl gas is effectively reduced (the content of the hydrolysate is reduced from more than 500ppm to less than 100 ppm). Because the HCl purification tower adopts fresh hydrochloric acid without hydrolysate to wash HCl gas, the content of impurities in the HCl gas at the tower top is greatly reduced, the problem of related equipment blockage is reduced, the equipment period is effectively prolonged, and the economic benefit of an enterprise is indirectly increased;
3. no waste acid is produced. Hydrochloric acid with impurities flowing out of the bottom of the first HCl purification tower circularly flows back to the hydrolysis tower, so that the aim of recycling is fulfilled, and the defect of waste hydrochloric acid generated in the traditional process is effectively avoided;
4. the HCl gas released by the decompression tank is purified and dried by a second HCl purification tower and then is directly pressurized and conveyed to a chloromethane synthesis section, so that the increase of an HCl absorption tower and an alkaline washing tower in a subsequent section can be avoided, and although one drying tower is added, the investment and operation cost are still greatly reduced in the overall consideration, and the discharge amount of three wastes is reduced;
5. HCl gas with lower impurity content can be generated, and the product purity of the chloromethane synthesis section is improved;
6. effectively improving the product quality. After the oil phase generated by hydrolysis is subjected to operations of HCl precipitation by decompression, secondary extraction deacidification, stripping deacidification and the like, the Cl & lt- & gt content is greatly reduced to be less than 3PPM (the Cl & lt- & gt content in the hydrolysate is about more than 6PPM by a conventional method);
7. the reaction temperature of the hydrolysis tower of the hydrolysis process of the dimethyldichlorosilane is 50-90 ℃, the pressure range is normal pressure to 0.5MPag, the tower plate and the spiral heat pipe with special structures are arranged in the hydrolysis tower, the dimethyldichlorosilane is fed in a gas phase, and the materials in the hydrolysis tower are heated more uniformly, so that the reaction efficiency can be effectively improved, the reaction time is shortened, and the equipment period is prolonged;
8. the feeding state of the dimethyldichlorosilane can be switched. When the gas phase feeding does not meet the requirement, the gas phase feeding can be switched to a liquid phase feeding mode, and the gas phase feeding is mixed with hydrochloric acid returned from subsequent equipment, heated by a heater and fed from the bottom of the hydrolysis tower;
9. the dimethyl dichlorosilane adopts gas phase multi-section feeding, so that the reaction is more uniform and sufficient. Under the condition of the same total amount of feeding materials, the gas-phase multi-section feeding can improve the molar ratio of the dimethyldichlorosilane to the hydrochloric acid in the reactor to achieve the effect of improving the reaction conversion rate, and the feeding amount of the dimethyldichlorosilane of each section is 40-90%, 40-5% and 20-5%.
In conclusion, the reactor for the organic silicon hydrolysis reaction and the HCl refining system finally obtain the high-purity hydrolysate and the HCl gas through a series of technological processes.
Drawings
FIG. 1 is a schematic structural diagram of an organochlorosilane hydrolysis and hydrochloric acid purification system of the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.