What methods are currently used to purify hydrogen recovered in polysilicon production?
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What methods are currently used to purify recovered hydrogen? What are the commonly used methods currently?
Hydrogen is purified in the CDI plant; the general process involves cooling (to remove chlorosilanes), compression, absorption of HCL in an absorption tower, and the removal of any remaining HCL and chlorosilanes using activated carbon. The hydrogen obtained at this stage has a very high purity and can be used directly as hydrogen feed for reduction processes.
The poster is absolutely correct; that’s basically how it is. The hydrogen produced by the CDI can be used directly as a reducing gas in the reduction furnace, and its purity is very high
There is also a gradual cryogenic cooling method, but it doesn’t seem to be used very often these days. First, chlorosilanes are condensed using brine at around -20 degrees Celsius and Freon at around -60 degrees Celsius, and then HCl is condensed using liquid nitrogen at -196 degrees Celsius. What’s left is hydrogen.
Our company uses CDI technology!
Our company also uses CDI technology; we have three sets of it, named large CDI and small CDI
Stepwise cryogenic cooling is used in our chlorohydration process, with hydrogen being recycled
High-pressure and low-temperature adsorption using activated carbon can achieve a hydrogen purity of 99.9999%
Activated carbon is used to adsorb away the remaining HCL. What specific type of activated carbon is used? Coal or fruit shells?
It seems there is now a pressure swing adsorption technology that can recover chlorosilanes, remove hydrogen chloride at the same time, and the purity of the recovered hydrogen is high enough to be used directly.
Yes, I think the name of each company is Sichuan Kaiyuan