초록 ▼

Abatement of nitrogen oxides in an industrial exhaust gas is effected by reduction of the nitrogen oxides with ammonia in the presence of a catalyst comprising a porous crystalline siliceous solid such as a ZSM-5 type zeolite. Fast responses to changes of NOx load is achieved with a zeolite of low t

Abatement of nitrogen oxides in an industrial exhaust gas is effected by reduction of the nitrogen oxides with ammonia in the presence of a catalyst comprising a porous crystalline siliceous solid such as a ZSM-5 type zeolite. Fast responses to changes of NOx load is achieved with a zeolite of low to moderate acid activity. The catalyst may be virgin catalyst, aged catalyst previously used for the conversion of a hydrocarbon or an organic compound, or artifically aged catalyst.

대표청구항 ▼

A method for pretreating prior to discharge to the atmosphere an industrial exhaust gas contaminated with NOx, which method comprises: forming at a temperature of at least about 200°C. a mixture of said exhaust gas and added ammonia, said ammonia being added in an amount to satisfy approximately the

A method for pretreating prior to discharge to the atmosphere an industrial exhaust gas contaminated with NOx, which method comprises: forming at a temperature of at least about 200°C. a mixture of said exhaust gas and added ammonia, said ammonia being added in an amount to satisfy approximately the stoichiometric requirement for reduction of the NOx by NH3; and, contacting said mixture at 200°C. to about 600°C. and at a gas hourly space velocity effective to substantially reduce said NOx content with a commercial, spent organic conversion catalyst, said catalyst comprising a crystalline zeolite having a silica to alumina ratio of at least about 50 and a Constraint Index of 1 to 12.