Japan Gasoline Co., Ltd.

Jgc Corporation

Tadashi Asanabe

Noriyuki Suzuki

Tomiaki Yamada

Fusao Nishida

Tsutomu Yanagihara

Kintaro Tsuda

Takehiko Takeda

Katsuhiko Adachi

Katuaki Ohsato

Keiichiro Watanabe

Katshiko Adachi

Kiyoshi Morikawa

Toshihiro Ueno

Katsuaki Ohsato

The present invention relates to a catalyst comprising at least a metal salt of heteropoly-acid, which is composed of a sort of heteropoly-acid and one or more metals selected from a group of the first transition metals of the periodic table. The catalyst of the present invention exhibits high activity and selectivity in the catalytic reduction of nitrogen oxides with ammonia at a temperature of from 250.degree. to 550.degree. C. and offers high resistivity to the poisonous effect of sulfur oxides. It does not entail a wasteful use of the reducing agent, because the catalyst of the present invention does not accelerate the reaction of the reducing agent such as ammonia with oxygen coexisting in the waste gas to be treated, which results in the elimination of the undesired excessive consumption of the reducing agent. Therefore, this invented catalyst may provide a commercially advantageous process for removing harmful constituents, nitrogen oxides from a waste gas which contains the same and additionally, in some cases, sulfur dioxides.

Catalyst for reducing nitrogen oxides in a waste gas and a process for

A process for the removal of nitrogen oxides from a waste gas containing said nitrogen oxides in conjunction with sulfur oxides is disclosed, which process comprises allowing said waste gas to come into contact with ammonia as the reducing agent at temperature in the range of from 250.degree. to 550.degree. C in the presence of a catalyst wherein an active component containing iron or copper as the active metal is supported on a silica-alumina type carrier containing not less than 60% by weight of silica and the pore volume occupied by the pores measuring 150 A or over in diameter exceeds 0.15 cc/g, for thereby causing selective catalytic reduction of said nitrogen oxides.

Process for removal of nitrogen oxides from waste gas

A process for the removal of nitrogen oxides from a waste gas containing said oxides in conjunction with sulfur oxides which comprises contacting said waste gas with ammonia as a reducing agent at temperatures of from 250.degree. to 550.degree. C in the presence of a catalyst wherein an active component containing iron or copper as the active metal and a sulfate of aluminum are supported on a silica carrier.

Selective removal of nitrogen oxides from waste gas

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Tokyo, Japan

Tadashi Asanabe