Hitachi Zosen Corporation

The Pollution-related Health Damage Compensation and Prevention

The Pollution Related Health Damage Compensation & Prevention Association

Shigenori Onitsuka

Masayoshi Ichiki

Takanobu Watanabe

Atsushi Fukuju

Chikashi Inazumi

Yuki Sairyo

Masaki Akiyama

Hidetsugu Kobayashi

Michio Ishida

Toshio Hama

Yoshimasa Miura

Michio Ito

Etsuo Ogino

Teruo Iwamoto

Teruyuki Doi

Teruhiko Kawanabe

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

Disclosed is a method of adsorbing and removing NOx, by washing with water a gas discharged by ventilation from highway tunnels in a washing tower as pretreatment, and then adsorbing NOx in the gas with a rotary NOx adsorption unit. The washed gas may be heated by a heater which is placed between the washing tower and the rotary NOx adsorption unit.

Method of adsorbing and removing nitrogen oxides

The invention provides a furnace desulfurization process which includes supplying a desulfurizing agent into a furnace or flue to cause the agent to absorb SO.sub.2 from the exhaust gas, the desulfurizing agent being a salt obtained by at least partly neutralizing a Ca desulfurizing agent with an acid; a furnace desulfurization process which includes supplying a Ca desulfurizing agent into a furnace or flue to effect a first-stage desulfurization reaction, collecting ash containing a waste of the agent having an unreacted substance enclosed therein from the exhaust gas, adding an acid to the collected ash to at least partly neutralize the unreacted portion of the agent, and recycling the ash containing the resulting salt into the furnace or flue to effect a second-stage desulfurization reaction; a dry simultaneous desulfurization-denitration process which includes supplying a Ca desulfurizing agent into a furnace or flue to effect a desulfurization reaction, collecting ash containing a waste of the agent having an unreacted substance enclosed therein from the exhaust gas, adding a denitrating reducing agent to the collected ash, and recycling the ash containing the waste desulfurizing agent and the reducing agent into the furnace or flue to effect desulfurization and denitration reactions; and a dry simultaneous desulfurization-denitration process which includes supplying a Ca desulfurizing agent into a furnace or flue to effect a desulfurization reaction, collecting ash containing a waste of the agent having an unreacted substance enclosed therein from the exhaust gas, adding an acid to the collected ash to at least partly neutralize the unreacted substance, adding a denitrating reducing agent to the ash containing the resulting salt, and recycling the ash containing the salt and the reducing agent into the furnace or flue to effect desulfurization and denitration reactions.

Dry processes for treating combustion exhaust gas

The invention provides a method of removing NOx by adsorption wherein a gas containing NOx at a low concentration is brought into contact with an adsorbent comprising a copper salt supported on zeolite serving as a carrier, whereby the NOx is adsorbed and removed efficiently. The adsorbent for use in this method comprises at least one copper salt supported on natural or synthetic zeolite, the copper salt being selected from the group consisting of copper chloride, double salt of copper chloride and ammine complex salt of copper chloride. The apparatus of the invention for purifying an NOx-containing gas comprises an adsorptive dehumidifier for dehumidifying the gas with a dehumidifying agent and regenerating the agent with a purified gas, and an adsorptive denitration unit for denitrating the dehumidified gas. The denitration unit has an adsorbent regenerating zone provided with a channel for recycling an NH.sub.3 -containing regenerating gas and with a channel for withdrawing a portion of the regenerating gas from the recycling channel, passing the withdrawn gas through a denitration reactor and then releasing the denitrated gas into the atmosphere.

Method of removing NOx by adsorption, NOx adsorbent and apparatus for

Growing community of inventors

Ikoma, Japan

Shigenori Onitsuka