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Title: Limestone-gypsum flue gas desulfurization process

Abstract

A flue gas desulfurization process capable of producing a high purity gypsum and also making equipment employed as minimum as possible is provided, which process comprises the steps of cooling and dedusting flue gas containing SO /SUB x/ ; contacting the cooled gas with a slurry containing limestone to remove SO /SUB x/ by absorption and also form CaSO/sub 3/; controlling the pH of the resulting slurry and then blowing air therein to form gypsum; and separating gypsum from the resulting slurry. As a modification of the above process, the slurry of the above second absorption step is further fed to the above first cooling step where unreacted limestone and SO /SUB x/ are reacted to form CaSO/sub 3/.

Inventors:
; ; ; ; ;
Publication Date:
OSTI Identifier:
5782839
Patent Number(s):
US 4487784
Assignee:
Babcock-Hitachi Kabushiki Kaisha (Japan) EDB-85-072528
Resource Type:
Patent
Resource Relation:
Patent Priority Date: Priority date 22 Feb 1982, Japan; Other Information: PAT-APPL-350598
Country of Publication:
United States
Language:
English
Subject:
32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; 54 ENVIRONMENTAL SCIENCES; FLUE GAS; DESULFURIZATION; GYPSUM; PRODUCTION; ADSORPTION; AIR POLLUTION ABATEMENT; LIMESTONE; ALKALINE EARTH METAL COMPOUNDS; CALCIUM COMPOUNDS; CALCIUM SULFATES; CARBONATE ROCKS; CHEMICAL REACTIONS; GASEOUS WASTES; MINERALS; OXYGEN COMPOUNDS; POLLUTION ABATEMENT; ROCKS; SEDIMENTARY ROCKS; SORPTION; SULFATE MINERALS; SULFATES; SULFUR COMPOUNDS; WASTES; 320305* - Energy Conservation, Consumption, & Utilization- Industrial & Agricultural Processes- Industrial Waste Management; 500200 - Environment, Atmospheric- Chemicals Monitoring & Transport- (-1989)

Citation Formats

Kuroda, H., Hashimoto, T., Kanda, O., Nishimura, M., Nishimura, T., and Nozawa, S.. Limestone-gypsum flue gas desulfurization process. United States: N. p., 1984. Web.
Kuroda, H., Hashimoto, T., Kanda, O., Nishimura, M., Nishimura, T., & Nozawa, S.. Limestone-gypsum flue gas desulfurization process. United States.
Kuroda, H., Hashimoto, T., Kanda, O., Nishimura, M., Nishimura, T., and Nozawa, S.. 1984. "Limestone-gypsum flue gas desulfurization process". United States. doi:.
@article{osti_5782839,
title = {Limestone-gypsum flue gas desulfurization process},
author = {Kuroda, H. and Hashimoto, T. and Kanda, O. and Nishimura, M. and Nishimura, T. and Nozawa, S.},
abstractNote = {A flue gas desulfurization process capable of producing a high purity gypsum and also making equipment employed as minimum as possible is provided, which process comprises the steps of cooling and dedusting flue gas containing SO /SUB x/ ; contacting the cooled gas with a slurry containing limestone to remove SO /SUB x/ by absorption and also form CaSO/sub 3/; controlling the pH of the resulting slurry and then blowing air therein to form gypsum; and separating gypsum from the resulting slurry. As a modification of the above process, the slurry of the above second absorption step is further fed to the above first cooling step where unreacted limestone and SO /SUB x/ are reacted to form CaSO/sub 3/.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 1984,
month =
}
  • In this paper oxidation of calcium bisulfite in aqueous solutions was studied, in connection with the limestone-gypsum flue gas desulfurization process. Experimental measurements of the oxidation rate were carried out in a laboratory scale stirred reactor with continuous feeding of both gas and liquid phase. A calcium bisulfite clear solution was used as liquid phase, and pure oxygen or mixtures of oxygen and nitrogen were used as gas phase. Experiments were carried out at T = 45 C varying the composition of the liquid phase and the oxygen partial pressure. Manganous sulfate was used as catalyst. The analysis of themore » experimental results showed that the kinetics of bisulfite oxidation in the presence of MnSO{sub 4} follow a parallel reaction mechanism, in which the overall reaction rate can be calculated as the sum between the uncatalyzed rate (3/2 order in bisulfite ion) and the catalyzed reaction rate (first order in manganous ion).« less
  • In a process for desulfurizing flue gase containing SO/sub 2/ by the lime-gypsum process wherein said SO/sub 2/ is absorbed in an aqueous solution of Ca(OH)/sub 2/ containing CaCl/sub 2/, the improvement comprising maintaining the concentration of Ca(OH)/sub 2/ in said absorbing solution at a level between 0.001% and 0.1% by weight and maintaining the concentration of CaCl/sub 2/ in said absorbing solution at less than 40% by weight, whereby the formation of gypsum scale is prevented.
  • This patent describes a sodium-limestone double alkali process for the continuous desulfurization of flue gas, having the steps of absorbing sulfur dioxide from an SO/sub 2/-containing gas stream in an absorber with an aqueous solution of sodium sulfite and sodium bisulfite, diverting at least a portion of the absorber effluent solution for regeneration with limestone, introducing limestone into the diverted absorber effluent solution to convert bisulfite to sulfite, separating by-product solids from the limestone-treated solution, and returning regenerated solution to the absorber, the improvement for increasing the utilization of the limestone used during the regeneration operation.
  • A combined cooling water/flue gas desulfurization process is described comprising: (a) contacting a gas with water in a cooling tower the gas having a lower temperature than the water such that upon contact the water is cooled by the transfer of thermal energy from the water to the gas. The water comprising between about 0.2 and about 100 ppm active by weight of an inhibitor formulation comprising polyacrylate, polymaleic anhydride, and phosphonate; (b) contacting a sulfur-containing gas with reagent slurry in a flue gas desulfurizer thereby desulfurizing the sulfur containing gas; and (c) supplying at least a portion of themore » water from the cooling tower to make up at least a portion of wash water in the desulfurizer, the water being supplied in an amount sufficient to maintain between about 0.01 and about 20 ppm active by weight of the inhibitor formulation in the reagent wash water.« less
  • A method of controlling the continuous operation of the absorption and regeneration processes of a sodium-limestone double alkali flue gas desulfurization system, in which measurements of absorber effluent solution pH or flow diverted for regeneration are used as the primary control parameter governing the limestone addition rate.