Babcock-hitachi Kabushiki Kaisha

Mitsubishi Hitachi Power Systems, Ltd.

Mitsubishi Power, Ltd.

Atsushi Katagawa

Hiroshi Ishizaka

Takanori Nakamoto

Takuro Ueda

Hirofumi Kikkawa

Hajime Okura

Fumito Nakajima

Hiroshi Kuroda

Shigehito Takamoto

Hiroyuki Kaku

Masakatsu Nishimura

Shigeru Nozawa

Jun Shimamura

Naoki Oda

Hiroyuki Nosaka

Kouji Muramoto

Tomoyuki Konishi

Noriyuki Imada

Shinya Ii

Ryota Ochiai

Naruhito Omine

Yoshiaki Mitsui

Wakako Shimohira

Mitsuharu Kon

Masayuki Yamamoto

Kunikatsu Yoshida

Hirotaka Yamanari

An exhaust gas treatment apparatus which includes a denitration device, a dust collector, and a desulfurization device in order, respectively, in a flow path of exhaust gas discharged from a boiler, wherein a heavy-metal component removal device is provided in the exhaust gas flow path between the dust collector and the desulfurization device. This device is provided with: an absorption tower including a nozzle which sprays acidic absorption liquid on the exhaust gas, a tank which stores liquid which has absorbed a heavy metal, and a pump which supplies the nozzle with the liquid in the tank; a neutralizing tank which neutralizes the liquid drawn from the absorption tower; and a separator which separates the neutralized liquid into a solid and a liquid component. Since a small amount of heavy metal can be removed in the absorption tower, re-emission of the heavy metal by the desulfurization device is prevented.

Coal-fired boiler exhaust gas treatment apparatus and coal-fired boiler exhaust gas treatment method

In order to heighten the recovery of activated carbon by separation in a flotation device and stably inhibit mercury from being re-emitted in a desulfurization/absorption tower and from coming into gypsum to be recovered, a method is provided, the method comprising: adding activated carbon to an absorption liquid to be sprayed into the desulfurization/absorption tower to thereby remove mercury components from the flue gas simultaneously with desulfurization of the flue gas; sending the absorption liquid used for the desulfurization to the flotation device to thereby form a foam bubble layer; reducing the drainage volume so that the physical properties of the bubble layer are within given ranges, in such an amount that the concentration of chlorine ions in the absorption liquid does not exceed a given value; and simultaneously adding Ca and/or Mg ions and a frothing agent to the absorption liquid.

Method and device for wet flue-gas desulfurization

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

In an absorbing tower including an absorption unit of relatively small diameter capable of absorption and removal by an absorbent slurry for exhaust gas purification and a tank unit of relatively large diameter for temporarily storing the absorbent slurry flowing down from the absorption unit, the tank unit and the absorption unit are joined together by a conical member. By disposing an entrance flue at the conical member, a distance from an upper portion of the conical member to a spray header is shortened, and a height of the absorbing tower can be reduced accordingly. By extending a front end of the entrance flue to the absorption unit into which droplets of the absorbent slurry fall, a high-temperature exhaust gas from a boiler, etc., that has passed through the entrance flue, is made to pass through a circumference of the conical member so that an inexpensive material can be used in the conical member.

Wet flue-gas desulfurization equipment

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

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

Absorption liquid recirculating pipes fitted with absorption tower (absorber) recirculating pumps corresponding to individual spray headers are inserted from the void tower portion inside absorption tower, near the liquid surface of liquid trapping portion (recirculation tank), in the interior of the absorption tower, erected vertically from substantially the center of the absorption tower and connected to respective spray headers provided in multiple stages along the direction of gas flow. Multiple nozzles of each of the spray headers are disposed mutually concentrically or rectangularly on a plane orthogonal to the direction of flue gas flow within the absorption tower. Thus, there can be provided a wet flue gas desulfurization apparatus (system) that is capable of large-capacity flue gas treatment and that in a plant where highly efficient desulfurization of flue gas of high SOx concentration is demanded, even when the amount of liquid circulated through the absorption tower is increased, can avoid increasing of the height of absorption tower and the power of absorption tower recirculating pumps and can realize easily disposing of footpath for maintenance.

Wet flue gas desulfurization apparatus

Wet-type flue gas desulfurization plant

Growing community of inventors

Hiroshima, Japan

Atsushi Katagawa