Mitsubishi Heavy Industries Limited

Mitsubishi Jukogyo Kabushiki Kaisha

Nichias Corporation

Mitsubishi Jukogyo Kaisha

Osamu Naito

Atsushi Morii

Yoshiaki Obayashi

Toshiyuki Onishi

Kozo Iida

Kouzo Iida

Satoru Serizawa

Hitoshi Nakamura

Norihisa Kobayashi

Shigeru Nojima

Shigeyuki Nishijima

Shuya Nagayama

Jun Tanabe

Shozo Kaneko

Akira Hattori

Nobuaki Murakami

Kikuo Tokunaga

Toshiaki Ohkubo

Kazuo Ideue

Toshihiko Imamoto

Masanori Demoto

Masaaki Taniguchi

Teruko Shimada

Mitsunori Ooizumi

Kiyoaki Imoto

A high temperature denitration catalyst of a gas turbine single plant contains TiO, at least one of WOand MoOand VOof 0.5 wt % or less, preferably 0.2 wt % or less, or none of VO, and is optimized to be used in a temperature range up to a maximum 450 to 600&#xb0; C. The used high temperature denitration catalyst is immersed into a V-containing water solution and dried and/or burned. An intermediate temperature denitration catalyst is produced containing a VOcomponent of 0.5 wt % or more, preferably 1.0 wt % or more, and is optimized for use in a temperature range of 250 to 450&#xb0; C. This intermediate temperature denitration catalyst is re-used in a combined cycle plant after being modified or in other plants.

Gas turbine single plant modifying method, a catalyst re-using method and a re-produced catalyst

An ammonia generating method characterized by generating ammonia by the contact hydrolysis of urea by contacting at 200&deg; C. or more an aqueous solution of urea with a contact hydrolysis catalyst containing at least one selected from the group consisting of hydroxides, carbonates, and silicates of alkaline metals as the main component, and a combusted exhaust gas processing method using the ammonia generated by the method.

Exhaust gas processing method

There are provided a honeycomb catalyst in which irregularities are formed on a catalyst inside wall in a honeycomb hole, and a manufacturing method for a honeycomb catalyst by using an extrusion molding method, in which extrusion molding is effected by using a mold having a means for providing irregularities to a catalyst inside wall of a honeycomb hole.

Honeycomb catalyst and manufacturing method therefor

The present invention provides a denitration catalyst which is designed to show a drop of the mechanical strength of the carrier to an acceptable extent even when used with an exhaust gas containing sulfur oxides while making the use of excellent water resistance or electrical insulating properties inherent to glass fibers and a process therefor. The denitration catalyst comprises a catalytically active component supported on a structure comprising a glass fiber free of B.sub.2 O.sub.3, an inorganic filler and an inorganic binder.

Catalyst and process for the production thereof

Disclosed are (1) a method for the regeneration of a denitration catalyst wherein, in order to regenerate a denitration catalyst having reduced denitration power, the catalyst is cleaned with a cleaning fluid having a hydrofluoric acid concentration of 0.3 to 3% by weight and maintained at a temperature of 20 to 80.degree. C., and (2) a method for the regeneration of a denitration catalyst which comprises the steps of cleaning a denitration catalyst having reduced denitration power under the conditions described in (1) above, drying the cleaned catalyst, and impregnating the catalyst with a catalytically active component so as to support it on the catalyst.

Method for the regeneration of a denitration catalyst

Disclosed is an ammonia adsorption apparatus for removing ammonia contained in a treated gas discharged from a denitrator for decomposing nitrogen oxides present in exhaust gas using ammonia as a reducing agent, comprising at least two adsorption towers into which ammonia-containing exhaust gas is introduced in a vertical direction for removing the ammonia by adsorption, wherein, during regeneration of each adsorption tower, hot gas used for desorption purposes flows from a top toward a bottom of the adsorption tower and cooling gas flows from the bottom toward the top of the adsorption tower.

Ammonia adsorption apparatus

The present invention relates to a method for removing clogging dust in gas passing holes in a honeycomb catalyst. A honeycomb catalyst whose gas passing holes are clogged with dust in exhaust gas is immersed in water in a vessel, and then the vessel is closed and vacuum suction is exerted, by which water is allowed to flow in the gas passing holes in the honeycomb catalyst to remove dust in the gas passing holes.

Method for removing clogging dust in honeycomb catalyst

This invention effectively utilizes a solid type honeycomb-shaped NO.sub.x removal catalyst which has been used in a catalytic ammonia reduction process and hence reduced in NO.sub.x removal power, and thereby provides an inexpensive catalyst having NO.sub.x removal power equal to that of a fresh catalyst. The nitrogen oxide removal catalyst of this invention, which is useful in a process wherein ammonia is added to exhaust gas and nitrogen oxides present in the exhaust gas are catalytically reduced, has a two-layer structure composed of a lower layer comprising a spent solid type nitrogen oxide removal catalyst and an upper layer comprising a fresh TiO.sub.2 -WO.sub.3 -V.sub.2 O.sub.5 ternary or TiO.sub.2 -WO.sub.3 binary catalyst powder which has been applied to the lower layer so as to give a coating thickness of 100 to 250 .mu.m. Moreover, the catalyst power constituting the upper layer is a catalyst powder obtained by pulverizing a spent solid type nitrogen oxide removal catalyst.

Nitrogen oxide removal catalyst

A high-performance rectifying device promotes the diffusion of energy, temperature and concentration in a fluid stream with a small pressure loss. The device is a lattice type rectifying device provided within a fluid flow passageway for equalizing the flow velocity distribution of the same fluid. Lattice elements each consist of two triangular plates disposed so as to form two opposed surfaces of a pyramid having its apex on the downstream side of the fluid flow and two other triangular plates forming two opposed surfaces of another pyramid having its apex jointed with the first-mentioned apex and having its bottom surface positioned on the downstream side of the fluid flow. The latter two opposed surfaces have their orientations deviated by 90 degrees from the two opposed surfaces on the upstream side. The lattice elements are arrayed in juxtaposition in directions perpendicular to the fluid flow with the orientation of adjacent lattice elements deviated by 90 degrees from each other and are connected in such a manner that the bottom surfaces of the above-mentioned pyramids may form a lattice. Furthermore the ratio of the length, in a direction parallel to the flow, of the lattice element to the breadth, in the direction perpendicular to the flow, of the lattice element should be kept in a range of 1.5-2.0. The lattice element may also be formed of a rectangular plate twisted by 90 degrees in the direction along the direction of the fluid flow.

Rectifying device

A method for recovering an ammonia adsorbent which comprises streaming an NO.sub.x -containing gas at 300.degree.-600.degree. C. through an ammonia adsorbent layer which adsorbs ammonia and which is saturated with ammonia.

Method for recovering ammonia adsorbent

A method for treating ammonia in an exhaust gas on the downstream side of a dry denitration device using ammonia as a reducing agent comprises the step of alternately carrying out ammonia adsorption and ammonia desorption/decomposition to continuously treat ammonia in the exhaust gas in a plurality of constitutional units parallelly connected on an exhaust gas line, the aforesaid constitutional units being constituted so as to carry out the steps of adsorbing/removing ammonia in an ammonia adsorbent-filling tower disposed at a position, where an exhaust gas temperature is 200.degree. C. or less, on the downstream side of the dry denitration device; heating, up to a temperature of 300.degree. C. or more, the ammonia adsorbent-filling tower on which ammonia is adsorbed in a saturated state, to desorb ammonia; and decomposing ammonia in an ammonia decomposition catalyst-filling tower disposed on a desorption ammonia gas line.

Method for treating ammonia

A method for the denitration of exhaust gas from a gas turbine or an internal combustion engine which comprises (a) reducing a part of the NO.sub.2 constituting NO.sub.x contained in the exhaust gas to NO by means of a reduction catalyst bed for reducing NO.sub.2 to NO, the reduction catalyst bed being installed in flow communication with the exhaust gas outlet of the gas turbine or internal combustion engine, and (b) injecting NH.sub.3 into the exhaust gas within an exhaust heat recovery unit and then decomposing and removing NO.sub.x contained in the exhaust gas and now composed chiefly of NO, by means a denitration catalyst bed installed within the exhaust heat recovery unit to effect the catalytic reduction of NO.sub.x with NH.sub.3.

Method for the denitration of exhaust gas

A method for denitrating an exhaust gas is disclosed which comprises the steps of injecting ammonia from an ammonia injection device into a high-temperature exhaust gas containing nitrogen oxides in a temperature range of 480.degree. C. or more, and then bringing a mixture of ammonia and the high-temperature exhaust gas into contact with a denitration catalyst to reduce the mixture, said method being characterized in that ammonia is injected through the ammonia injection device in which at least an inner surface is subjected to an aluminizing treatment, whereby ammonia is prevented from decomposing; and an apparatus for denitrating an exhaust gas is also disclosed.

Growing community of inventors

Nagasaki, Japan

Osamu Naito