Patent ID: 8167975

Claim:
An exhaust gas purifying method including the steps of: removing sulfur trioxide (SO 3 ) by spraying a basic substance in a flow channel of an exhaust gas discharged from a combustion apparatus that includes a boiler; thereafter removing soot/dust in the exhaust gas by a dry precipitator; then removing sulfur dioxide (SO 2 ) in the exhaust gas by a desulfurizer; further removing sulfur trioxide (SO 3 ) and soot/dust remaining in the exhaust gas by a wet precipitator; and then discharging the purified exhaust gas into air; and wherein the basic substance and a heavy metal adsorbent, sprayed into the exhaust gas to remove heavy metals contained in the exhaust gas, are sprayed into an exhaust gas flow channel at a downstream side of the dry precipitator and an upstream side of the desulfurizer.