Problems in TCS synthesis
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1. How can the wear problem associated with the transportation of silicon powder be effectively resolved, and what methods can be used to avoid the need to replace valves and pipelines? 2. Can adding hydrogen to dilute hydrogen chloride in the synthesis furnace help in the synthesis of TCS? Personally, I believe that hydrogen addition can inhibit the formation of STC and DCS from a chemical equilibrium perspective, but it also inhibits the formation of TCS. However, the ratio of hydrogen to hydrogen chloride can be controlled; the key is to determine what ratio is most favorable for the formation of TCS. 3. In terms of economic analysis, what is the yield of trichlorosilane that makes it more cost-effective to produce it rather than purchasing it?
1: There’s no other way; one can only reduce wear by choosing the appropriate pipes and valves； The replacement cycle for pipelines is quite long. The biggest problem right now are the valves; many factories can’t last even half a year, I guess? 2: Too much hydrogen will definitely inhibit the reaction; generally, the ratio of hydrogen to chlorine is 1.1 ； 3: I’m not sure what yield you’re referring to
This post was last edited by limingshuguang on 2010-1-13 at 16:11. 1. Reducing the bends in the pipes can lessen the friction caused by silicon powder on those pipes; for some critical areas, it may be appropriate to consider using ceramic-lined pipes. 2. Regarding the situation mentioned by the original poster, it is assumed that under the same reaction conditions, hydrogen and TCS can produce silicon powder and hydrogen chloride. But in reality, this reverse reaction process hardly occurs, or rather, the reaction rate is extremely slow. As for the excess hydrogen in the synthesized hydrogen chloride mentioned on the 2nd floor, it is mainly due to the combustion of chlorine during the synthesis of hydrogen chloride. It is also because free chlorine will directly react with silicon powder to form STC. 3. This depends on one’s actual production conditions; of course, it is necessary to adjust the process parameters appropriately in order to increase the yield of TCS. The higher, the better. 4. Personal opinion, for reference only. I hope everyone will continue to communicate.
This post was last edited by limingshuguang on 2010-1-13 at 16:12. The hydrogen gas I mentioned is used to dilute hydrogen chloride, in order to increase the yield of TCS; according to the chemical equilibrium constants, the partial pressure of TCS is proportional to the partial pressure of hydrogen, while the partial pressure of STC is proportional to that of hydrogen chloride. Therefore, increasing the partial pressure of hydrogen is beneficial for the synthesis of TCS. However, since silicon powder reacts with hydrogen chloride to produce TCS and hydrogen, according to chemical equilibrium, the addition of hydrogen inhibits the synthesis of TCS; it also inhibits the formation of STC. Thus, it is necessary to add hydrogen in an appropriate amount – neither too much nor too little. Generally, there is a required ratio between hydrogen and hydrogen chloride. I would like to know what this ratio is and how it is determined. Thank you all. This problem has been bothering me for a long time
"Generally, there is a required ratio between hydrogen and hydrogen chloride; I would like to know what this ratio is and how it is determined. Trying using 95 volumes of hydrogen chloride along with 5–10 volumes of hydrogen to see if this improves the results might be useful. Each factory should determine this value based on the conditions of its own reaction reactors. Theoretical calculations for this purpose are quite complex. Adding hydrogen not only benefits the reaction but also has an adverse effect on the formation of STC. Moreover, dilution makes the reaction proceed more gently. This is just my personal opinion, for reference only!!
The market price of purchased trichlorosilane is approaching 10,000 yuan per ton; it’s necessary to synthesize TCS on our own