Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An absorbing tower provided with plural spray headers (3) which each have a plurality of spray nozzles (5) 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 (5) to absorb and remove sulfur oxide contained in exhaust gas, wherein each spray nozzle (5) is of an annular spray type (a hollow cone type) and the spray nozzles (5) in the neighborhood of the tower wall have such a structure that the fluid is sprayed radially at spray angles of 50 to 80° with the direction counter to the flow of exhaust gas as the center, while the nozzles (5) in the central part of the tower have such a structure that the fluid is sprayed radially at spray angles of 80 to 130° with the direction counter to the flow thereof as the center.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: An absorbing tower provided with plural spray headers (3) which each have a plurality of spray nozzles (5) 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 (5) to absorb and remove sulfur oxide contained in exhaust gas, wherein each spray nozzle (5) is of an annular spray type (a hollow cone type) and the spray nozzles (5) in the neighborhood of the tower wall have such a structure that the fluid is sprayed radially at spray angles of 50 to 80° with the direction counter to the flow of exhaust gas as the center, while the nozzles (5) in the central part of the tower have such a structure that the fluid is sprayed radially at spray angles of 80 to 130° with the direction counter to the flow thereof as the center.

Abstract: An elongated absorber housing, including an inlet duct and an outlet duct, is integrally provided on an upper portion of a circulation tank. The absorber is a self-supporting structure supported by only the circulation tank. At least the furthest upstream spraying stage in a spraying zone in the inlet duct includes spray pipes provided with spray nozzles for spraying an absorbing liquid in a direction cocurrent with gas flow, and at least the furthest downstream spraying stage includes spray nozzles for spraying the absorbing liquid in a direction countercurrent to the gas flow. The absorber is an integral structure in which the upper portion of the circulation tank forms a part of the duct, whereby the absorber is self-supportable and, moreover, is of a simple structure, giving it high strength and eliminating of the need for provision of fitments for supporting the absorber.