Patent ID: 8728210

Claim:
An exhaust gas treatment apparatus for treating tail gas containing dust and ammonia gas from a semiconductor equipment, comprising: an ammonia absorption system, comprising: a dust scrubber for receiving the tail gas and removing the dust from the tail gas to produce dust removal tail gas; a wetted-wall tower connected to the dust scrubber for absorbing the ammonia gas in the dust removal tail gas and converting the ammonia gas into aqueous ammonia; a circulation tank connected to the wetted-wall tower for receiving the aqueous ammonia and providing an absorption solution for the wetted-wall tower, wherein the absorption solution serves to absorb the ammonia gas separated from the dust removal tail gas; a mist absorber connected to the wetted-wall tower for absorbing the ammonia gas that remains in the dust removal tail gas and converting the ammonia gas to low concentration of aqueous ammonia; a water sealed vacuum pump connected to the mist absorber for pumping, washing and exhausting the dust removal tail gas; and a first reservoir connected to the circulation tank for collecting the aqueous ammonia; and an ammonia conversion system, comprising: an evaporator connected to the first reservoir for vaporizing the aqueous ammonia to form gaseous ammonia; a dehydrator connected to the evaporator for removing moisture of the gaseous ammonia and pre-cooling the gaseous ammonia; a cooling and compression device connected to the dehydrator for cooling and compressing the gaseous ammonia to form liquid ammonia; a refrigerator connected to the cooling and compression device for supplying cryogenic liquid to the cooling and compression device and generating heat; a heat pump connected to the evaporator and the refrigerator respectively, the heat pump supplying the heat generated from the refrigerator to the evaporator and supplying cooling water in the ammonia conversion system; and a second reservoir, connected to the cooling and compression device for collecting and storing the liquid ammonia.