What are the causes of the introduction and generation of C and CH4 in polysilicon production? Please advise
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What are the causes of the introduction and generation of C and CH4 in polysilicon production?
1. C is introduced into the thermohydrogenation converter. 2. The carbon tower in the recycling workshop also introduces C. 3. C in the system reacts with hydrogen to produce CH4.
Additional note from upstairs: The graphite in the reduction furnace may react with hydrogen, introducing carbon into the system.
Thank you for your analysis, I’ve learned something!
Here, we regularly analyze the carbon content in the distillation section and in the recovered chlorosilanes. Where does this carbon come from? Is it in the form of CH4 in the gas phase? What is its form in chlorosilanes? I’m not familiar with this; I’d like some guidance
In addition to what was mentioned on the first floor, another source of C is the industrial silicon introduced during TCS synthesis; this substance exists in liquid form and may undergo CH4 formation through reactions at high temperatures when it enters the reduction furnace. Additionally, since the hydrogenation system operates continuously, graphite rods are also introduced! The original poster needs to figure out the raw materials involved in the entire polysilicon production process; by using the elimination method, a conclusion can be drawn!
Measuring methane is essentially measuring total carbon
The CDI activated carbon column also introduces C; hydrogen is recovered in a closed-loop system, while the activated carbon column has little ability to remove or control these C compounds, leading to a cumulative effect
The introduction of C occurs mainly through synthesis, exhaust gases, and hydrogenation-reduction; in chlorosilanes, it exists primarily in the form of methylchlorosilane.
Reply to 8# zhengjiulu: How is carbon specifically introduced into the adsorption tower? Or rather, what reaction takes place? It seems that our company uses activated carbon to absorb CH4, and regularly checks the CH4 content in hydrogen. Isn’t the purpose supposed to be to remove C?
Additionally, if the C content in polysilicon products increases, and equipment issues are ruled out, should analysis and inspection be carried out at those specific production stages to identify the cause?