| 摘要 |
PROBLEM TO BE SOLVED: To provide methods by which ammonia can be easily and efficiently recovered and recycled from exhaust gas containing a small amount of ammonia, the exhaust gas being exhausted from a production process of a gallium nitride compound semiconductor.SOLUTION: Exhaust gas is filtered with a filter to remove a solid compound contained in the exhaust gas, the filtered exhaust gas is pressurized and cooled with a heat pump to liquefy ammonia contained in the exhaust gas, and liquefied ammonia is separated from hydrogen and nitrogen to recover liquefied ammonia. Recovered liquid ammonia is evaporated and mixed with another crude ammonia, and the resulting mixed gas is purified and supplied to a production process of a gallium nitride compound semiconductor. |
