Where is instrument air and pure nitrogen used in polysilicon plants?
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I’m a beginner. May I ask where instrument air and pure nitrogen are used in polysilicon plants? Thank you
OP, instrument air is definitely used for instrument control valves and other pneumatic instruments. Nitrogen is mainly used for heating silicon powder and pneumatic conveying; it is no longer needed after synthesis.
Reply to 2# king70868: Thank you very much. May I ask what are the usage standards for instrument air and pure nitrogen? What level below should the dew point be kept?
Instrument air is used for automatic valves to keep them in the open or closed state, while ordinary nitrogen is used for purging. For displacement or silicon powder delivery
Purity nitrogen is generally used in pneumatic conveying during the synthesis of trichlorosilane and in the feeding process of the synthesis furnace, with a dew point of less than -60 degrees. Instrument air is used in various instruments and pneumatic valves; it has a dew point of less than -50 degrees, an oil content of less than 0.01 PPM, dust particle sizes of less than 0.01 microns, and a dust content of less than 0.01 milligrams per cubic meter.
Thank you so much to all these experts for sharing; I’ve learned a lot