PURPOSE: To conveniently and efficiently purify the NOx in a waste combustion gas of natural gas by bringing the waste gas contg. oxygen into contact with a specified selective reduction catalyst to reduce and purify the NOx in the waste gas.
CONSTITUTION: A waste natural gas combustion gas contg. oxygen is brought into contact with a selective reduction catalyst contg. at least one kind of metal selected from Cu, Co, Mn, Fe, Ni, Zn and Ag in the presence of a ≥3C paraffin and a ≥2C olefin to reduce and purify the NOx in the waste gas. Meanwhile, at least one kind of metal selected from Cu, Co, Mn, Fe, Ni, Zn and Ag is deposited on alumina, zeolite or silicate to obtain the catalyst. Consequently, the NOx are efficiently removed from a waste natural gas combustion gas having high contents of oxygen and methane.
OKADA OSAMU
KOUKETSU MIKAKO
AOYANAGI YUSUKE
FUJITA HIROKI
