The use of packed towers in the polysilicon industry has the following disadvantages
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A) High purity is required for trichlorosilane, hence high cleanliness standards are needed for the fillers； B) The trichlorosilane raw material may contain silicon powder, which can easily clog the filler ； C) Since the operating pressure of the distillation column is lower than the steam pressure in the reboiler, a leak in the reboiler can cause corrosion of the packing, resulting in significant losses. Currently, in the polysilicon industry both domestically and internationally, sieve tray towers are still primarily used for the distillation of trichlorosilane
The original poster is right; plate towers are used for distillation
Screen plate tower for distillation, packed tower for dry recovery
This post was last edited by wangxuefeng2004 on 2010-1-6 at 11:31. However, the fill tower offers significant advantages, as follows; let’s continue the discussion: 1) The pressure drop is very low. In the filler, heat and mass transfer occur by convection at the surface of the liquid film in the gas phase, with no resistance from a liquid layer on the tray or from the sieve pores. 2) Adequate heat and mass exchange leads to high separation efficiency, thereby increasing the extraction rate of the product ； 3) It has high operational flexibility; it does not suffer from flooding or leakage, thus offering a wide load adjustment range and strong adaptability. The load regulation range can be 30% to 110%, while that of the tray tower is 70% to 100%. 4) There is little liquid retention, resulting in fast startup and load adjustment speeds ； 5) It can save energy. Due to low resistance, 6) the tower diameter can be reduced.
In the polysilicon industry today, which companies use packed towers in the distillation process? What kind of packing can be used?