A wet desulfurization apparatus includes a chamber enclosing a space for passing flue gas and including a first barrier partitioning the space into first and second chamber regions, a flue gas inlet to introduce raw flue gas into the first chamber region, and a flue gas outlet to discharge desulfurized flue gas from the second chamber region; a second barrier partitioning a slurry reservoir into a first reservoir part to store a first pH alkaline slurry and a second reservoir part to store a second pH alkaline slurry; a first sprayer to spray the alkaline slurry from the first reservoir part into the first chamber region to remove sulfur from the flue gas in the first chamber region; and a second sprayer to spray the alkaline slurry from the second reservoir part into the second chamber region to remove sulfur from the flue gas in the second chamber region.

A wet desulfurization apparatus includes a chamber enclosing a space for passing flue gas and including a tubular barrier partitioning the space into an inner chamber region having a first volume and an outer chamber region surrounding the inner chamber region and having a second volume, a flue gas inlet to introduce raw flue gas into the outer chamber region, and a flue gas outlet to discharge desulfurized flue gas from the inner chamber region; a slurry reservoir disposed under the chamber to receive and store an alkaline slurry; first and second sprayers to spray the alkaline slurry into the outer and inner chamber regions, respectively, in order to remove sulfur from the flue gas in the corresponding chamber region; and a demister disposed in the inner chamber region between the second sprayer and the flue gas outlet to remove mist from the flue gas in the inner chamber region.

Provided is an absorber that removes sulfur oxide in a flue gas with an absorbent, an absorbent storing unit that stores the absorbent that has absorbed the sulfur oxide, an oxidation-reduction potential meter that measures an oxidation-reduction potential of the absorbent in the absorbent storing unit, a reducing additive supplying unit that supplies a sulfur oxoacid reducing additive into the absorbent storing unit, and a control device that controls the reducing additive supplying unit based on a measured value of the oxidation-reduction potential of the absorbent measured with the oxidation-reduction potential meter, wherein the reducing additive supplying unit supplies the sulfur oxoacid reducing additive when the measured value of the oxidation-reduction potential has exceeded an upper limit of an appropriate range of the oxidation-reduction potential.

Apparatus and methods for controlling aerosol production during absorption in ammonia desulfurization, by removing sulfur dioxide in flue gas with an absorption circulation liquid containing ammonium sulfite, so as to control the aerosol production during absorption in ammonia desulfurization. Efficient desulfurization and dust removal may be achieved by staged solution composition control and reaction condition control. At the same time ammonia escape and aerosol production during absorption may be controlled. The flue gas may be subjected to preliminary temperature lowering and purification, and may be allowed to contact with an absorption circulation liquid and a fine particle washing circulation liquid sequentially. Levels of solution compositions and reaction temperatures may be controlled.

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.

Apparatus and methods for controlling aerosol production during absorption in ammonia desulfurization, by removing sulfur dioxide in flue gas with an absorption circulation liquid containing ammonium sulfite, so as to control the aerosol production during absorption in ammonia desulfurization. Efficient desulfurization and dust removal may be achieved by staged solution composition control and reaction condition control. At the same time ammonia escape and aerosol production during absorption may be controlled. The flue gas may be subjected to preliminary temperature lowering and purification, and may be allowed to contact with an absorption circulation liquid and a fine particle washing circulation liquid sequentially. Levels of solution compositions and reaction temperatures may be controlled.

Apparatus and methods for controlling aerosol production during absorption in ammonia desulfurization, by removing sulfur dioxide in flue gas with an absorption circulation liquid containing ammonium sulfite, so as to control the aerosol production during absorption in ammonia desulfurization. Efficient desulfurization and dust removal may be achieved by staged solution composition control and reaction condition control. At the same time ammonia escape and aerosol production during absorption may be controlled. The flue gas may be subjected to preliminary temperature lowering and purification, and may be allowed to contact with an absorption circulation liquid and a fine particle washing circulation liquid sequentially. Levels of solution compositions and reaction temperatures may be controlled.

A method of spray drying and washing using a spray drying apparatus, includes: spraying dehydrated filtrate from a spray nozzle hung down from a top side of the spray drying apparatus; introducing a part of flue gas into the spray drying apparatus to dry the dehydrated filtrate; wherein a compressed air is introduced into the spray nozzle to facilitate the spraying and into the wash nozzle to perform air purging during the spray drying, and jetting washing liquid from a wash nozzle provided on a side wall of the spray drying apparatus to wash the spray nozzle and an inside of the spray drying apparatus body, wherein the feeding of the dehydrated filtrate to the spray nozzle is stopped during the washing.

A system for sulphur removal from a flue gas. The system includes an absorber, a reaction tank and a buffer tank. The buffer tank is connected to the reaction tank by a communicating vessel passage.

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.