Flue gas desulfurization gypsum

Taha R, Donald S (1992) The use of flue gas desulfurization gypsum in civil engineering applications. Proc Conf Utilization of Waste Materials in Civil Engineering Construction, ASCE, New York, p 635... 

Mercury in Flue Gas Desulfurization Gypsum FROM Coal Combustion Processes... 

Mercuiy in Flue Gas Desulfurization Gypsum from Coal Combustion Processes 99... 

Emissions control systems play an important role at most coal-fired power plants. For example, PC-fired plants sited in the United States require some type of sulfur dioxide control system to meet the regulations set forth in the Clean Air Act Amendments of 1990, unless the boiler bums low sulfur coal or benefits from offsets from other highly controlled boilers within a given utiUty system. Flue-gas desulfurization (FGD) is most commonly accomphshed by the appHcation of either dry- or wet-limestone systems. Wet FGD systems, also referred to as wet scmbbers, are the most effective solution for large faciUties. Modem scmbbers can typically produce a saleable waUboard-quaUty gypsum as a by-product of the SO2 control process (see SULFURREMOVAL AND RECOVERY). 

A. D. Randolph and D. Etherton, Study of Gypsum Crystal Nucleation and Growth Rates in Simulated Flue Gas Desulfurization Eiquors, EPRI Report CS1885, Electric Power Research Institute, Palo Alto, Calif., 1981. 

Minerals Limestone Fillers Paper coatings Flue gas desulfurization Kaolin Gypsum Alumina Precious metals hheration... 

Desox A flue-gas desulfurization process in which limestone slurry absorbs the sulfur dioxide, forming calcium sulfite. This is then oxidized to saleable gypsum ... 

Dowa A flue-gas desulfurization process in which the sulfur dioxide is absorbed in a basic aluminum sulfate solution. The product solution is oxidized with air and reacted with limestone to produce gypsum. Developed by the Dowa Mining Company, Japan, in the early 1980s. In 1986 it was in use in nine plants in Japan and the United States. 

Poz-O-Tec A flue-gas desulfurization process which produces a fibrous form of gypsum, convenient for disposal. In a demonstration project, an artificial reef was built from the product in the Atlantic Ocean near Fire Island, New York. Developed by IU Conversion Systems, Philadelphia, PA. 

A novel Double Draw-Off (DDO) ciystallizer has been designed in order to improve the particle size distribution in the precipitation of CaS03 V 20 simulated Flue Gas Desulfurization (FGD) liquor. The effects of DDO ratio and residence time on the mean particle size were studied. Industrial conditions were maintained in all experiments as far as practical. Significant improvement in mean particle size was achieved. The performance of an actual industrial DDO ciystallizer (DuPont) for gypsum ciystallization was reported. 

Randolph, A.D., D.E. Vaden and D. Stewart, "Improved Crystal Size Distribution of Gypsum from Flue Gas Desulfurization Liquors," Chemical Engineering Symposium Series, No. 240, SQ 110 (1984). 

The goal of this research was to improve activity coefficient prediction, and hence, equilibrium calculations in flue gas desulfurization (FGD) processes of both low and high ionic strength. A data base and methods were developed to use the local composition model by Chen et al. (MIT/Aspen Technology). The model was used to predict solubilities in various multicomponent systems for gypsum, magnesium sulfite, calcium sulfite, calcium carbonate, and magnesium carbonate SCU vapor pressure over sulfite/ bisulfite solutions and, C02 vapor pressure over car-bonate/bicarbonate solutions. 

An important technology for removal of S02 is Flue Gas Desulfurization (FGD), carried out in units known as scrubbers. Most scrubbers contact the flue gas with a slurry of lime or limestone to capture the sulfur oxides and produce a sludge containing calcium sulfite and calcium sulfate. However, disposal of sludge is another environmental problem, and some scrubbers include oxidation to convert all the calcium sulfite to sulfate (gypsum), which can be used for wallboard manufacture. Fluidized-bed combustion units add a sulfur... 

Kurabo A flue-gas desulfurization process involving scrubbing with an acidic solution of ammonium sulfate. The product is gypsum. Used in Japan. 

Thoroughbred A family of flue-gas desulfurization processes. Commercialized versions have been called Thoroughbred-101, Thoroughbred-102, and Thoroughbred-121. Another name used for the last is CT-121. They are integrated flue-gas desulfurization processes that achieve limestone neutralization, oxidation, and conversion to gypsum, in a complex jet bubbling reactor. Developed... 

Flue gas desulfurization systems are classifled in two general categories. One group involves throwaway product systems where sulfur product (untreated or treated) is disposed of as a landfill. The other group produces saleable products such as sulfuric acid, elemental sulfur or, as in Japan, gypsum for wallboard and sodium sulfite for paper mills. 

For flue-gas desulfurization, lime and limestone processes are utilized in which the furnace gas is scrubbed with an aqueous liquid containing the necessary quantity of ealcium hydroxide or calcium carbonate for neutralizing the acidic furnace gas components. The end products are calcium sulfite/calcium sulfate sludges or on complete oxidation gypsum ... 

In the Federal Republic of Germany in 1994 the consumption of gypsum was 6.2 10 t/a, of which 60% was provided by natural gypsum and 40% by REA-gypsum (gypsum from flue gas desulfurization). The proportion of REA-gypsum should increase by the year 2000 to 55% corresponding to 5.6 10 t/a. 

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