Mitsubishi Heavy Industries Limited

Mitsubishi Jukogyo Kabushiki Kaisha

Eiji Ochi

Toru Takashina

Susumu Okino

Kiyoshi Okazoe

Naohiko Ukawa

Atsushi Tatani

Kazuaki Kimura

Taku Shimizu

Masao Hino

Takashi Haruki

Takeo Shinoda

Shintaro Honjo

Masakazu Onizuka

Makiichi Ishihara

Toshihiro Sato

Koichiro Iwashita

Yoshihiro Okamoto

Shinichiro Kotake

Manabu Oda

Atsushi Yoshioka

Hideki Kamiyoshi

Tetsu Ushiku

Atsumasa Endo

Takao Sodeshita

A flue gas desulfurization apparatus includes an absorption tower that absorbs sulfur oxide in a flue gas, and drift suppression members that are arranged near a bend portion of a purified gas exhaust passage arranged at an outlet portion of the absorption tower, the drift suppression members serving to collect mist particles.

Flue gas desulfurization apparatus

The present invention provides a method for the treatment of mercury present in exhaust gas wherein, after a chlorinating agent is added to exhaust gas containing nitrogen oxides, sulfur oxides and mercury, the exhaust gas is subjected to a reductive denitration treatment in the presence of a solid catalyst and then to wet desulfurization using an alkaline absorbing fluid, the method being characterized by measuring the mercury concentration in the exhaust gas after the wet desulfurization; calculating a predicted value of the inlet mercury concentration before the reductive denitration treatment on the basis of the measured mercury concentration; and controlling the feed rate of the chlorinating agent added prior to the reductive denitration treatment, according to the deviation of the predicted value from a reference inlet mercury concentration, as well as a system for the treatment of exhaust gas. Thus, the present invention provides an exhaust gas treatment process permitting the removal of mercury, and this process makes it possible to achieve efficient operation of the system and maintain the performance thereof without exerting any adverse influence the units within the system.

Method for the treating in exhaust gas and exhaust gas treating system

Five combustion exhaust gas treatment systems capable of removing dust and selenium (Se) in combustion exhaust gas and making harmless are proposed: (1) combustion exhaust gas is cooled to 350&deg; C. or less, dust is separated, Se is transformed into insoluble compound, and Se is separated; (2) combustion exhaust gas is cooled to 350&deg; C. or less, dust is separated, Se elution preventive agent is added, and dust is formed into scale; (3) dust in combustion exhaust gas is collected by dust collector, dust is formed into slurry by making use of part of circulation liquid in desulfurization apparatus, and tetravalent Se in dust slurry is transformed into insoluble compound, which is separated into solid and liquid; (4) dust is separated from combustion exhaust gas by dust collector, and it is heated to gasify Se, and is led into desulfurization apparatus, etc., and formed into slurry, and Se is made into insoluble compound; and (5) a treating agent for making tetravalent Se insoluble is added to part of circulation liquid in desulfurization apparatus, and it is sprayed into combustion exhaust gas to make Se insoluble.

Combustion exhaust gas treatment system

The present invention provides an exhaust gas treatment process wherein exhaust gas containing mercury and sulfur dioxide is subjected to a desulfurization treatment in a desulfurizing absorption tower and then passed through a mist eliminator for removing and recovering mist from the desulfurized exhaust gas, the process including the step of removing mercury from the desulfurized exhaust gas by feeding thereto an oxidizing agent such as sodium hypochlorite and an antioxidant such as methanol unreactive with the oxidizing agent at a position upstream of the aforesaid mist eliminator.

Exhaust gas treatment process

There is provided a heavy oil fired boiler exhaust gas treatment apparatus which removes soot and dust and SO in the heavy oil fired boiler exhaust gas efficiently at a low cost without using an excessively large apparatus. The treatment apparatus comprises a charging device provided at the inlet of an absorption tower of a wet type exhaust gas desulfurizer and neutralizer pouring means A provided on the upstream side of the charging device to pour a neutralizer into exhaust gas and neutralize SO in the exhaust gas.

Heavy oil fired boiler exhaust gas treatment apparatus

A liquid extracting apparatus in accordance with the present invention is configured so that a connection pipe (suction-side pipe) of a pump for extracting slurry liquid content is connected to the upper end side of a liquid content introduction path to which slurry in a tank can be introduced to attain the precipitation and separation of solid content, and a number of tubes are packed at the lower end portion of the liquid content introduction path . The present invention can provide a simple liquid extracting apparatus that can effectively extract only liquid content in the slurry (suspension) moving in the tank.

Liquid extracting apparatus

The dust concentration of the flue gas leaving an electrostatic precipitator and introduced into an absorption tower of a desulfurizer is adjusted to a level of 100 to 500 mg/Nm.sup.3. At the same time, a dust slurry having a higher dust concentration is separated and withdrawn from the slurry within the aforesaid absorption tower, and then subjected to a solid-liquid separation treatment. Thus, solid matter containing dust at a high concentration is extracted and discharged out of the system of the desulfurizer.

Flue gas treating process

Five combustion exhaust gas treatment systems capable of removing dust and selenium (Se) in combustion exhaust gas and making harmless are proposed: (1) combustion exhaust gas is cooled to 350.degree. C. or less, dust is separated, Se is transformed into insoluble compound, and Se is separated; (2) combustion exhaust gas is cooled to 350.degree. C. or less, dust is separated, Se elution preventive agent is added, and dust is formed into scale; (3) dust in combustion exhaust gas is collected by dust collector, dust is formed into slurry by making use of part of circulation liquid in desulfurization apparatus, and tetravalent Se in dust slurry is transformed into insoluble compound, which is separated into solid and liquid; (4) dust is separated from combustion exhaust gas by dust collector, and it is heated to gasify Se, and is led into desulfurization apparatus, etc., and formed into slurry, and Se is made into insoluble compound; and (5) a treating agent for making tetravalent Se insoluble is added to part of circulation liquid in desulfurization apparatus, and it is sprayed into combustion exhaust gas to make Se insoluble.

The present invention provides an evaporative concentration apparatus for waste water having an evaporating vessel 2 for evaporatively concentrating waste water and a heater 3 for circularly heating an in-vessel liquid in the evaporating vessel 2, in which the whole or part of thermal energy of generated steam 6 discharged from the evaporating vessel 2 is recovered by an absorption heat pump 29, and the thermal energy is supplied to the heater 3. According to the present invention, evaporative concentration can be effected efficiently in the evaporating vessel by effectively utilizing the thermal energy of generated steam, and also the operation of evaporative concentration apparatus can be performed stably by stably securing heating steam quantity.

Evaporative concentration apparatus for waste water

This invention provides a flue gas treating system which, though having a basic construction using a small-sized and high-performance gas-liquid contact apparatus comprising the combination of a parallel-flow absorption tower and a counterflow absorption tower, can reduce the ammonia concentration in the treated flue gas to a low level. This system includes a tank (21) for holding an absorbing fluid fed thereto; an inlet side absorption tower (22) of the counterflow type which extends upward from one lateral part of the tank (21) and in which untreated flue gas (A) is introduced from its lower end and brought into gas-liquid contact with the absorbing fluid within the tank (21); and an outlet side absorption tower (23) of the parallel-flow type which extends upward from another lateral part of the tank (21) and in which the flue gas leaving the inlet side absorption tower (22) is introduced from its upper end and brought into gas-liquid contact with the absorbing fluid within the tank (21).

Flue gas treating system and process

An exhaust gas treatment apparatus for the removal of at least a sulfur dioxide gas and ammonia from an exhaust gas by bringing the exhaust gas into vapor-liquid contact with an absorbing liquid comprises an introduction-side tank to which the absorbing liquid is supplied, a parallel-flow type absorption tower positioned above the introduction-side tank; an ejection side tank positioned adjacent the introduction side tank; a counter-flow type absorbing tower positioned above the ejection side tank; a mist eliminator for removing splash mist from the exhaust gas; and a controller for controlling the pH of the absorbing liquid in one of the introduction-side absorption tower and the ejection-side absorption tower.

Exhaust gas treatment apparatus and method

The present invention provides a gas-liquid contact apparatus which can make the equipment more compact and reduce the cost while achieving high gas-liquid contact efficiency. In the apparatus of the present invention, an oxidation tank (2) is installed in proximity to an absorption tower (1), and an absorbing fluid (3) is stored in this oxidation tank (2). The level H of the absorbing fluid (3) is determined so as to be above the position of nozzles (7), whereby the absorbing fluid is spouted upward from the nozzles (7). Flue gas is introduced into the absorption tower (1) from a flue gas inlet section (8) and made to flow upward at a high velocity, so that the peaks of the spouted streams are raised above level H. The absorbing fluid (3) is caught by catcher device (11) installed at a position above level H, and returned to the oxidation tank (2) through a circulation pipe (12). An air pipe (20) is connected to the circulation pipe (12) so as to suck in air.

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Tokyo, Japan

Eiji Ochi