Babcock-hitachi Kabushiki Kaisha

Mitsubishi Hitachi Power Systems, Ltd.

Mitsubishi Power, Ltd.

Hiroshi Ishizaka

Hirofumi Kikkawa

Takanori Nakamoto

Fumito Nakajima

Shigehito Takamoto

Hiroyuki Kaku

Shigeru Nozawa

Masakatsu Nishimura

Atsushi Katagawa

Kazuki Kobayashi

Hiroyuki Nosaka

Yasuyoshi Kato

Naomi Imada

Eiji Miyamoto

Takuro Ueda

Takeshi Hirota

Hiroshi Takezaki

Hiroshi Kuroda

Toshio Katsube

Takashi Michimoto

Jun Shimamura

Masatoshi Fujisawa

Hajime Okura

Takayuki Saitou

Masayuki Yamamoto

Kunikatsu Yoshida

Mitsuharu Kon

Shinya Ii

Masatochi Fujisawa

Goki Sasaki

Yoshinori Taguchi

Ryota Ochiai

Naruhito Omine

Yoshiaki Mitsui

Takayuki Saito

A wet type flue-gas desulfurization apparatus, into which exhaust gas containing mercury goes, includes an upstream absorption tower, an upstream absorbent spray nozzle and a make-up water supply unit on an upstream side of a desulfurization apparatus body in a flow direction of the gas. The upstream absorption tower has a circulation tank reserving absorbent slurry. The make-up water supply unit supplies make-up water into the circulation tank to keep the chloride ion concentration of the absorbent in the circulation tank not lower than 50,000 ppm. Thus, it is possible to provide a wet type flue-gas desulfurization apparatus by which Hg can be prevented from being released again from the desulfurization apparatus, the purity of recovered gypsum can be increased and the usage of industrial water can be reduced.

Wet type flue-gas desulfurization method

After adjusting an exhaust gas temperature at an exit of a heat recovery unit () of an exhaust gas treating apparatus to not more than a dew point temperature of sulfur trioxide (SO), a heavy metal adsorbent is supplied from a heavy metal adsorbent supply unit () disposed in an exhaust gas at an entrance of a precipitator () or an intermediate position within the precipitator (), and the exhaust gas containing the heavy metal adsorbent is supplied into the precipitator (). Preferably at this stage, the heavy metal adsorbent is supplied into the exhaust gas at the entrance of the precipitator () 0.1 seconds after the exhaust gas temperature at the exit of the heat recovery unit () has been adjusted to not more than the dew point temperature of SO. Further preferably, in order to prevent acid corrosion of equipment, the heavy metal adsorbent is supplied after spraying an alkali into the exhaust gas at the entrance or exit of the heat recovery unit () and adjusting the exhaust gas temperature at the exit of the heat recovery unit to not more than the dew point temperature of SO. Accordingly, even when coal with a high sulfur content is used as fuel, heavy metals in the exhaust gas can be removed effectively.

Exhaust gas treating method and apparatus

An absorbing tower is provided in its side wall with a gas entrance for introducing a combustion exhaust gas into the absorbing tower, and an absorbing liquid is sprayed from the nozzles of a spray header into the exhaust gas introduced to rise from the gas entrance. A trough is arranged in the side wall of the absorbing tower and above the gas entrance, and a nose having a horseshoe shape in a top plan view and extending into tower is disposed in the tower side wall portion of the gas entrance other than the portion arranging the trough and at the same or at substantially the same height as the portion of the trough. The absorbing liquid, which is sprayed from the nozzle and drops along the absorbing tower wall portion, is rescattered to the center portion of the absorbing tower excepting the entrance of the absorbing tower, so that the gas-liquid contact efficiency is improved while suppressing an increase in pressure loss, thereby to prevent the drift of the gas at the tower wall portion.

Wet-type exhaust desulfurizing apparatus

A system is provided that prevents inhibition of adsorption of Hg and other heavy metals by activated carbon or other heavy metal adsorbent due to prior adsorption of sulfur trioxide (SO) in an exhaust gas containing SO. As it has been found that while SOis adsorbed, the adsorption of SOprecedes the adsorption of Hg and other heavy metals onto activated carbon, a basic substance injection system is disposed along an exhaust gas flow channel at an upstream side of an activated carbon injection system, thereby attaining effective removal of Hg and other heavy metals from the exhaust gas by adsorption thereof onto surface pores of the activated carbon. The SOconcentration after removal by basic substance conversion is computed from the SOconcentration before removal, and the activated carbon injection rate can be controlled based on the concentration after removal.

Exhaust gas purifying method and apparatus

An absorbing tower provided with plural spray headers () which each have a plurality of spray nozzles () and are arranged in a multi-stage state in the flow direction of exhaust gas, in which an absorption liquid containing a slurry of limestone or lime is sprayed through the nozzles () to absorb and remove sulfur oxide contained in exhaust gas, wherein each spray nozzle () is of an annular spray type (a hollow cone type) and the spray nozzles () in the neighborhood of the tower wall have such a structure that the fluid is sprayed radially at spray angles of 50 to 80&#xb0; with the direction counter to the flow of exhaust gas as the center, while the nozzles () in the central part of the tower have such a structure that the fluid is sprayed radially at spray angles of 80 to 130&#xb0; with the direction counter to the flow thereof as the center. According to the invention, the channeling of exhaust gas in the tower can be inhibited by using two kinds of spray nozzles () to thereby prevent the desulfurization performance from lowering caused by blow-by of exhaust gas in the neighborhood of the tower wall. Further, an extremely high pressure loss can be inhibited by the flow-regulating effect of sprayed droplets. Thus, a wet-type exhaust gas desulfurizer with a reduced total cost is obtained.

Wet-type exhaust gas desulfurizer

A method and apparatus for treating an exhaust gas comprising heavy metals, wherein the apparatus comprises a heat recovery unit, recovering exhaust gas heat at an exit of the air preheater; a precipitator, collecting soot/dust contained in an exhaust gas at an exit of the heat recovery unit; a wet flue gas desulfurizer, removing sulfur oxides contained in the exhaust gas at the exit of the precipitator; and a reheater, heating the exhaust gas at the exit of the wet flue gas desulfurizer. Each of the heat recovery unit and the reheater has a heat exchanger tube, and a circulation line is disposed to connect the heat exchanger tubes. A sulfur trioxide (SO) removing agent is supplied to the upstream side of the heat recovery unit, and the temperature of the exhaust gas at the exit of the heat recovery unit is adjusted to not more than a dew point of sulfur trioxide.

Method and apparatus for treating discharge gas

A particulate material removing filter for exhaust gas from a diesel engine is provided. The particulate material removing filter is formed by laminating metal laths having an oxidation catalyst layer containing a noble metal that oxidizes nitrogen oxide in exhaust gas into nitrogen dioxide. The metal laths are laminated to form a laminate in such a manner that the drawing direction of the metal lath processing differs by 90 degrees with each other.

Filter for exhaust gas from diesel engine and equipment

A particulate matter-removing filter being resistant to clogging and ash blocking, requiring no special means such as back-washing and heating combustion, and being formed of inexpensive materials; and exhaust emission controlling method and device using this. (1) A particulate-matter-containing exhaust emission controlling filter which uses as a basic unit a pair of porous corrugated sheet and a porous flat sheet that support an exhaust emission controlling catalyst, has a molding formed by laminating the porous corrugated sheets so that their ridge lines alternately cross perpendicularly, has one of side surfaces, perpendicularly crossing the corrugated sheet ridge lines, of the molding or mutually-adjoining two surfaces that are the perpendicularly-crossing side surfaces sealed, and has exhaust gas in-flow passage and out-flow passage respectively formed between porous corrugated sheets via a porous flat sheet. (2) A filter having the exhaust emission controlling catalyst that is an oxidizing catalyst for oxidizing nitrogen monoxide in an exhaust gas.

Particulate matter-containing exhaust emission controlling filter, exhaust emission controlling method and device

A wet-type flue gas desulfurization method and plant making use of a solid desulfurizing agent in which exhaust gas exhausted from a combustion apparatus such as a boiler is brought into contact with absorbing liquid to absorb sulfur oxide from the exhaust gas into the absorbing liquid followed by neutralization of the absorbing liquid containing the sulfur oxide thus absorbed. The solid desulfurizing agent is selectively retained in an absorbing liquid neutralizing zone and the absorbing liquid, containing water as a main constituent and solid products formed from the absorbed sulfur oxide, is selectively removed from the neutralizing zone. In the neutralizing zone the upward flow of the absorbing liquid, optionally augmented by an upward flow of air or water, forms a fluidized bed of limestone particles, thereby preventing coating of the limestone by gypsum and thereby retaining reactivity of limestone. According to the present invention, coexistence of Al and F in the absorbing liquid seldom deteriorates the desulfurizing performance. Further, it is possible to reduce power and cost required to grind limestone and to achieve a higher desulfurizing performance.

Wet-type flue gas desulfurization plant and method making use of a solid

Wet-type flue gas desulfurization plant

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Hiroshima, Japan

Hiroshi Ishizaka