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Gas Processing
When the plasma converted gas leaves the gasifier it is contaminated with a number of substances that can damage both the environment and machinery. It therefore has to be cleaned before it can be used. The gas treatment system is comprised of seven stages:
Gas Processing
- Initial quench to reduce the temperature of the gas from 1000C° to 650C°
- High temperature cyclone separator to remove particulates
- Quench stage (with heat recovery, if desired)
- Cartridge dust collector to remove particulates
- Selective catalytic reduction to remove NOx
- Packed column scrubber to remove acids and volatized metals
- Final polishing with granulated activated charcoal
The quenches are required to reduce the temperature of the gas for processing purposes, and also to stop the formation of dioxin by de-novo synthesis. The cyclone and filter stages remove the majority of particulates that are carried over with the gas. The collected particles are batch fed back to the converter for further reaction or incorporation in the silicate. Due to the high temperature in the plasma converter vessel, nitrogen compounds react to form oxides of nitrogen. These unwanted compounds are removed by selective catalytic reduction. In the packed column scrubber, acid gases such as hydrogen chloride are removed by dissolving them in water or a caustic solution. Any particles remaining in the gas are also removed in the scrubber.
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