Distillation of trichlorosilane -- material balance
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Trichlorosilane is produced by the boiling chlorination method, and the crude trichlorosilane obtained as a result needs to be distilled. What are the low-boiling and high-boiling compounds present in crude trichlorosilane? If the components of the feed and the separation requirements are known, how can material balance be performed for the distillation process? Thank you all for reading and responding. This post was last edited by LHY8771 on 2009-3-24 15:01.]
The high-boiling substances are mainly silicon tetrachloride and phosphorus compounds, while the low-boiling substances include dichlorodihydrosilane and boron-containing compounds
Excuse me, my colleague upstairs: in the low-boiling substances, is there a higher content of dichlorodihydrosilicon or of boron compounds? Are boron compounds mainly boron trichloride?
Among the low-boiling compounds, dichlorodihydrosilicon is present in relatively large amounts; boron compounds are trace impurities, and even if they are concentrated, their amount cannot exceed that of dichlorodihydrosilicon； As for whether the main compound of boron is boron trichloride, it’s hard to say; it seems there are other compounds as well, but I’m not sure what they are:(
I think when raising this question, it would be good for the original poster to mention how many stages of distillation are used in your process. Incidentally, if it’s a two-stage distillation process, the output from the light-end tower equals the average low-boiling-point composition in the feed multiplied by the feed volume, while the output from the heavy-end tower equals the high-boiling-point content multiplied by the feed volume. Of course, this can only serve as a reference for operations.
I used three-stage distillation in the design. The third stage separates silicon tetrachloride from high-boiling substances. So can we also use what was mentioned on the 5th floor for a rough estimate? Also, I would like to know what the main high-boiling substances are that are separated at the third stage?