What does energy conservation and emission reduction in polysilicon production entail? And how does it work?
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How does the waste heat recovery from reduction furnaces work in polysilicon production?
The most common method is to use flash evaporation for distillation to supply heat to the reboiler; another approach is to send hot water at 150 degrees directly to the distillation unit. Jiangsu Shuangliang’s lithium bromide refrigeration units are said to be able to divide a stream of hot water into two parts: one part is cooled, while the other part undergoes flash evaporation. Has anyone seen such a refrigeration unit?
My company uses waste heat to heat the feedstock STC and hydrogen
It is preheated as a raw material for thermal hydrogenation. What type of preheater do you use? What is the average logarithmic temperature difference? According to my calculations, the temperature gradient isn’t very large; it’s about 10–20 degrees difference. Why doesn’t your company use exhaust gas to preheat the raw material mixture?
It seems that the polysilicon plants designed by design institutes these days basically use the waste heat for flash evaporation, thereby recovering steam and reducing energy consumption!
Reply to 4# jesscy: Our company does not use heating for STC and hydrogen; instead, it relies on air cooling and 7-degree chilled water
The boiler water can also be preheated!
Reply to 7# wei8jun: The inlet pipeline of the preheating boiler is too long.
The equipment from Shuangliang that we use works pretty well
What our company does is to use the waste heat for flash evaporation, recover the low-pressure steam, and reuse it in the distillation reboiler in order to reduce energy consumption!
Is this meaningful? From the perspective of energy conservation, it makes no sense to utilize the low-grade heat from steam condensate.