Babcock-hitachi Kabushiki Kaisha

Isato Morita

Yasuyoshi Kato

Tomihisa Ishikawa

Yoshinori Nagai

Hiroshi Kuroda

Takashi Michimoto

Masato Mukai

Akihiro Yamada

Masaharu Morii

Fumito Nakajima

Hirofumi Kikkawa

Kunihiko Konishi

Toshio Katsube

Ikuhisa Hamada

Yoshiro Inatsune

An apparatus for removing of traces of toxic substances from exhaust gas, comprising, disposed in sequence from the upstream side in a flow channel of exhaust gas emitted from combustion equipment, a denitration unit including a denitration catalyst layer capable of removing nitrogen oxides from the exhaust gas and capable of oxidizing metallic mercury; an air preheater adapted for heat exchange between air for combustion in the combustion equipment and the exhaust gas; a dust removal unit having a bag filter containing a catalyst for metallic mercury oxidation; and a desulfurization unit for removing sulfur oxide from the exhaust gas. The bag filter may be disposed in advance of the desulfurization unit. Thus, there can be provided an apparatus for removing of traces of toxic substances from exhaust gas that is stable over a prolonged period of time and is highly reliable; and provided a method of operating the same.

Apparatus for removing of trace of toxic substance from exhaust gas and method of operating the same

A catalyst unit is constructed by alternately stacking rectangular catalyst elements (1) formed by cutting catalyst support plates coated with a catalytic material and having ribs (2) inclined at 45.degree. to one specified side edge (1a) of each thereof, and those turned upside down in a case, and the catalyst unit is disposed in a gas passage with the ribs (2) of the catalyst elements (1) inclined at an angle greater than 0.degree. and smaller than 90.degree. to the direction of the gas flow (6). When the catalyst unit comprising the catalyst elements (1) coated with a denitrating catalyst is placed in the gas passage, the ribs (2) of the catalyst elements (1) blocks the gas flow (6) and generate turbulent currents on the downstream side thereof to promote the contact of ammonia and NOx contained in the exhaust gas with the catalyst. When the gas flow (6) is disturbed, the thickness of laminar films covering the surface of the catalyst elements (1) is reduced, so that ammonia and NOx can be easily diffused and the catalytic activity can be enhanced. The catalyst elements exhibits their catalytic abilities effectively without entailing significant pressure loss in the gas flow.

Catalyst unit and gas purifying apparatus

A catalyst for purifying an exhaust gas includes a first component having activity for reducing nitrogen oxides with ammonia and a second component having at least one of activity for forming nitrogen oxide from ammonia and activity for forming carbon dioxide from carbon monoxide. The first component is a composition containing an oxide of at least one member selected from titanium, vanadium, tungsten and molybdenum and the second component is a composition containing a salt of a noble metal selected from platinum, palladium and rhodium or any one of these noble metals supported on a porous material selected from zeolites, alumina and silica. The invention further provides a method for purifying an exhaust gas containing NOx, CO and leak NH.sub.3 using the catalyst.

Catalyst for purifying exhaust gas

In an apparatus for removing NOx from a flue gas comprising an ammonia injection tube in a flue gas duct, an NOx removal reactor containing a catalyst at the downstream side of the ammonia injection tube, and a bracket casing catalyst test pieces being provided in the reactor and fixed to the reactor in a detachable manner from the outside of the reactor apart from the catalyst, deterioration of catalyst can be monitored during the operation of the boiler plant and sampling of catalyst can be carried out through the catalyst sample pieces without discontinuing the operation of the apparatus for removing NOx.

Apparatus for removing nitrogen oxides

Growing community of inventors

Kure, Japan

Isato Morita