Hitachi Zosen Corporation

The Pollution-related Health Damage Compensation and Prevention

The Pollution Related Health Damage Compensation & Prevention Association

Masaki Akiyama

Masayoshi Ichiki

Atsushi Fukuju

Chikashi Inazumi

Shigenori Onitsuka

Takanobu Watanabe

Yuki Sairyo

Hidetsugu Kobayashi

Susumu Hikazudani

Kazuhiro Yano

Takehiro Shimizu

Hidetake Okamoto

A method for producing a catalyst of the present invention is characterized by sequentially performing the steps of: (i) dipping an end face portion of a carrier structure having a catalytic component carried thereon in an aqueous metal salt solution at a concentration of 2.7 to 3.88 mol/L in terms of mole of the metal; (ii) drying the dipped end face portion; (iii) dipping the dried end face portion again in an aqueous metal salt solution whose metal species is the same as that in the aqueous metal salt solution at a concentration of 2.7 to 3.88 mol/L in terms of mole of the metal; and (iv) performing a calcination treatment to harden the catalytic end face.

Method for production of catalyst and catalyst produced by the method

The invention provides a process for removing NOx which is free of impairment in denitration efficiency at a reaction temperature of up to 300&deg; C. even when the component molar ratio of NOx in the gas to be treated is NO >NO. For use in removing NOx from the gas to be treated and containing NO in a larger amount than NO, that is, having a (NO )/NOx ratio in excess of 0.5, by selective reduction with use of ammonia serving as a main reducing agent in the presence of a denitration catalyst, the process of the invention for removing NOx comprises adding to the denitration reaction system a substance for removing an excess of oxygen accumulating on catalyst active sites by selectively reducing the oxygen at not higher than 300&deg; C., for example, at 300 to 150&deg; C., in other words, a substance which reacts with the excess of oxygen on the catalyst active sites and becomes oxidized at not higher than 300&deg; C.

Method for removing NOx

The invention provides first to fourth adsorbents for removing low-concention nitrogen oxides. The first adsorbent comprises a carrier of gamma-alumina, and ruthenium supported-thereon. The second adsorbent comprises a carrier of anatase-type titania, and ruthenium supported thereon. The third adsorbent comprises ceramic paper retaining a carrier of anatase-type titania thereon, and ruthenium supported on the ceramic paper. The fourth adsorbent comprises ceramic paper retaining a carrier of anatase-type titania thereon, and a ruthenium halide and a halide of addition metal which are co-supported on the ceramic paper. These adsorbents are free of the influence of moisture and therefore usable without necessitating energy-consuming dehumidification or only with dehumidification on a reduced scale.

Adsorbents for removing low-concentration nitrogen oxides

The invention provides first to fourth adsorbents for removing low-concentration nitrogen oxides. The first adsorbent comprises a carrier of gamma-alumina, and ruthenium supported thereon. The second adsorbent comprises a carrier of anatase-type titania, and ruthenium supported thereon. The third adsorbent comprises ceramic paper retaining a carrier of anatase-type titania thereon, and ruthenium supported on the ceramic paper. The fourth adsorbent comprises ceramic paper retaining a carrier of anatase-type titania thereon, and a ruthenium halide and a halide of addition metal which are co-supported on the ceramic paper. These adsorbents are free of the influence of moisture and therefore usable without necessitating energy-consuming dehumidification or only with dehumidification on a reduced scale.

Absorbents for removing low-concentration nitrogen oxides

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Osaka, Japan

Masaki Akiyama