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Toda Kogyo Corporation

Masaki Ishihara

Yasuhiko Fujii

Tomoyuki Imai

Tomoko Okita

Toshiki Matsui

Satoshi Hatakeyama

Hiroshi Inoue

Takashi Okamura

Tatsuaki Baba

Masayuki Ukita

Kojiro Tsutsumi

An iron compound catalyst for inhibiting the generation of dioxin contains iron oxide particles, iron oxide hydroxide particles or mixed particles having a catalytic activity capable of converting not less than 15% of carbon monoxide into carbon dioxide when 2.8&times;10&minus;4 mol of iron oxide particles obtained by heat-treating the iron compound catalyst in air at a temperature of 800&deg; C. for 15 minutes, are instantaneously contacted with 6.1&times;10&minus;7 mol of carbon monoxide at a temperature of 250&deg; C. at a space velocity (SV) of 42,400 h&minus;1 in an inert gas atmosphere using a pulse catalytic reactor, the iron oxide particles or the iron oxide hydroxide particles have an average particle size of 0.01 to 2.0 &mgr;m, a BET specific surface area of 0.2 to 200 m2/g, a phosphorus content of not more than 0.02% by weight, a sulfur content of not more than 0.6% by weight and a sodium content of not more than 0.5% by weight. This iron compound catalyst enables complete combustion of municipal solid waste and decomposition of dioxin precursors even at a low combustion temperature in intermittently operated incinerators such as mechanical batch incinerators or semi-continuous incinerators, and can inhibit dioxin generation of due to a memory effect upon low-temperature combustion at the start-up or shut-down of the incinerators, without large-scale incinerator renovation or plant and equipment investment.

Iron compound catalyst for inhibiting generation of dioxin

The present invention relates to a process for treating a dioxin-containing exhaust gas which can inhibit the generation of dioxin occurring either in the course of cooling of the exhaust gas between a downstream portion subsequent to a combustion chamber and a dust collector or due to a memory effect upon low-temperature combustion in flues or dust collector at the start-up or shut-down of intermittent operation-type solid waste incinerators, without large-scale incineration facilities or plant renovation and equipment investment, and a composite catalyst composition for inhibiting the generation of dioxin, comprising an iron compound, an acid gas neutralizing agent and optionally an activated carbon.

Process for treating dioxin-containing exhaust gas and composite catalyst composition for inhibiting generation of dioxin

Composite catalyst composition for inhibiting generation of dioxin

An iron compound catalyst for inhibiting the generation of dioxin of the present invention, comprise iron oxide particles, iron oxide hydroxide particles or mixed particles thereof having a catalytic activity capable of converting not less than 15 % of carbon monoxide into carbon dioxide when 2.8&times;10,mol of iron oxide particles obtained by heat-treating said iron compound catalyst in air at a temperature of 800&deg; C. for 15 minutes, are instantaneously contacted with 6.1&times;10,mol of carbon monoxide at a temperature of 250&deg; C. at a space velocity (SV) of 42,400 h,in an inert gas atmosphere using a pulse catalytic reactor, the iron oxide particles or said iron oxide hydroxide particles having an average particle size of 0.01 to 2.0 &mgr;m, a BET specific surface area of 0.2 to 200 m,/g, a phosphorus content of not more than 0.02 % by weight, a sulfur content of not more than 0.6 % by weight and a sodium content of not more than 0.5 % by weight. Such an iron compound catalyst enables complete combustion of the municipal solid waste and decomposition of dioxin precursors even at a low combustion temperature in intermittently operated incinerators such as mechanical batch incinerators or semi-continuous incinerators, and can inhibit the generation of dioxin due to a memory effect upon low-temperature combustion at the start-up or shut-down of the incinerators, without large-scale incinerator renovation or plant and equipment investment.

Iron compound catalyst for inhibiting generation of dioxin and incineration process of municipal solid waste using the same

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Okayama-ken, Japan

Masaki Ishihara