The Chemical Design, Inc. Poly Plant Vent Gas recovery Process recovers approximately 98% of all components in the decomposer vent gas and delivers the following streams:
- Pure Hydrogen to be recycled to the Trichlorosilane vaporizer.
- Pure Hydrogen Chloride to be used in fluid bed reactors to produce SiHCl3.
- Mixed Chlorosilanes to be separated into SiHCl3 for reuse and SiCl4 for conversion to SiHCl3.
This process is also attractive environmentally because there are no waste streams to dispose of and the opportunity to introduce contamination is minimized because no outside streams such as water and caustic solution are brought in contact with the gas stream.
The use of this process with CDI's special grade activated carbon and properly selected materials of construction result in the production of a very high quality electronic grade polycrystalline silicon.