Distillation of trichlorosilane
Thread Content
Using the company’s distillation process for trichlorosilane, there are a total of 9 towers: 5 towers for the purification of crude trichlorosilane in the trichlorosilane production unit, 2 towers for the purification of chlorosilanes in the reduction off-gas recovery unit, and one tower each for the recovery of silicon tetrachloride and trichlorosilane. The process flow is as follows: Tower 1# removes light components. The crude chlorosilane from the trichlorosilane production workshop is fed into Tower #1. The gas at the top of the tower is condensed in a condenser; part of the condensate is recycled, while the rest goes into the tail gas condensate tank. The material at the bottom of the tower is sent to Tower 2 via the tank liquid pump. Tower 2 removes the Reorganization components. The gas at the top of Tower 2 is condensed in a condenser; part of the condensate is recycled, while part goes to Tower 3 for further purification. The material at the bottom of the tower enters Tower 9 for further separation. Tower 3 is a dual-purpose tower for light separation/removal. The gas at the top of Tower 3 is condensed in a condenser; part of the condensate is recycled, while the rest is sent either to Tower 4 or to the tail gas condensate tank, depending on testing and analysis results. The material at the bottom of the tower is either used for cyclic distillation after inspection and analysis in the chlorosilane storage tank, or it is sent to Tower 4 via the liquid pump at the bottom of Tower 3 for further purification. Tower 4 is a trichlorosilane purification tower. The gas at the top of Tower 4 is condensed in a condenser; part of the condensate is recycled back to the tower, while part goes to Tower 5 for further purification. The material at the bottom of the tower enters the chlorosilane storage tank for cyclic distillation. Tower 5 is a trichlorosilane purification tower. The gas at the top of Tower 5 is condensed in a condenser; part of the condensate is returned to the tower, while the rest, after passing quality checks, is sent to the product tank of Tower 5 for storage, thereby providing high-purity TCS for the reduction unit. The material at the bottom of the tower enters the chlorosilane storage tank for cyclic distillation. Tower 6 is a silicon tetrachloride purification tower. The crude chlorosilane from the reduced exhaust gas recovery workshop is fed into Tower 6. The gas at the top of the tower is condensed in a condenser; part of the condensate is returned to the tower, while another part goes to Tower 7 for further purification. The material at the bottom of the tower enters Tower 9 for further separation. The high-purity STC obtained from the lower side line is condensed and then transported to a silicon tetrachloride storage tank for storage, thereby supplying high-purity STC to the trichlorosilane production workshop. Tower 7 is a trichlorosilane purification tower. The gas at the top of Tower 7 is condensed in a condenser; part of the condensate is returned to the tower, while part goes to Tower 8 for further purification. The material at the bottom of the tower enters the feed trough of Tower 6 for cyclic distillation. The high-purity TCS extracted from the upper side line is cooled and then transported to the product tank of Tower 7 for storage, thereby supplying high-purity TCS to the reduction unit. Tower 8 is the trichlorosilane recovery tower. The gas at the top of Tower 8# is condensed in a condenser; part of the condensate is returned to the tower, while another part is sent to a low-boiling-point substances storage tank as low-boiling-point substances. It is then pumped to the process waste gas and waste liquid treatment unit for treatment or sold externally. The material at the bottom of the tower enters the chlorosilane storage tank for cyclic distillation. Tower 9 is the silicon tetrachloride recovery tower. The gas at the top of Tower 9 is condensed in a condenser; part of the condensate is returned to the tower, while another part is sent to a silicon tetrachloride storage tank to supply high-purity STC to the trichlorosilane production workshop. The material at the bottom of the tower is pumped to the process waste gas and waste liquid treatment unit for treatment or sold externally. To reduce the loss of chlorosilanes through venting, the non-condensable gases from all towers are fed into an exhaust gas condensation system where they are condensed at low temperatures to further recover the chlorosilanes. The uncondensed non-condensable gases are then sent to the process waste gas and waste liquid treatment units for further processing.
The process description is quite detailed; thanks for sharing!
Shouldn’t we give it a bit more prestige? I can’t upload many of the materials I use
The original poster’s information is quite good! Thank you
How are those towers for light-end and heavy-end separation actually operated?
It’s unknown what the distillation efficiency is for the nine towers, as well as the level of impurities present
The original poster’s information is really good! I work in the equipment industry; currently I’m working on distillation towers
There are so many. We only have a coarse separation column, a light-end removal unit, 2 heavy-end removal units, and one boron removal bed:shutup:
May I ask how tall the tower of the original poster is, how many trays it has, and could you also provide information on the opening ratio, weir height, and so on?
Thank you, OP! I’ve given you a score! I suggest the original poster could carry out a series of continuous publications on polysilicon-related content; I look forward to learning more continuously!