To make inexpensive the detoxification cost for dioxins by making a treating temperature lower than a boiling point of water by a method wherein a raw gas in a contact of an exhaust gas to a first treated liquid is brought in contact with a second treated liquid, and fly ashes caught in two processes are independently or jointly brought in contact with hydrochloric acidic aqueous solution dissolved by a reaction catalyst to dissolve dioxins in the fly ashes.
An incinerator exhaust gas which includes fly ash containing dioxins generated in an incinerator 31, is introduced to a waste heat boiler 32 via a line 41. After recovering a heat quantity, the exhaust gas is introduced into a first gas-liquid contact device 33 via a line 42. The exhaust gas is brought in contact with a fine liquid drop particle of a first treated liquid having been sprayed in a column via a line 45 to be quenched at a temperature of about 45 to 75°C. Simultaneously, a part of the fly ash in the exhaust gas and most of HCl are caught with the first treated liquid, and separated from the exhaust gas. The treated exhaust gas is introduced to a second gas-liquid contact device 34 via a line 43, is brought in contact with a second treated liquid, and the residual fly ash and SO2 in the exhaust gas are caught with the second treated liquid, and removed from in the exhaust gas. The dioxins in the fly ash included in the incinerator exhaust gas can be decomposed harmless highly efficiently at a low cost.
TAKEDA MASARU
KAWAMURA KAZUSHIGE
UCHIDA MINORU
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