Flue Gas Desulfurization Systems

Other Uses. Other uses include intermediate chemical products. Overall, these uses account for 15—20% of sulfur consumption, largely in the form of sulfuric acid but also some elemental sulfur that is used directly, as in mbber vulcanization. Sulfur is also converted to sulfur trioxide and thiosulfate for use in improving the efficiency of electrostatic precipitators and limestone/lime wet flue-gas desulfurization systems at power stations (68). These miscellaneous uses, especially those involving sulfuric acid, are intimately associated with practically all elements of the industrial and chemical complexes worldwide. 

Lime being unloaded at a power plant. The material will be used to reduce suliur dioxide emissions as part of its flue gas desulfurization system. (Corbis Corporation)... 

Kranz MWS A flue-gas desulfurization system based on activated carbon. One carbon bed removes most of the sulfur dioxide. Ammonia is then injected for the SCR process to occur in the second bed, which also removes the residual sulfur dioxide. The carbon is regenerated off-site. Developed by Krantz Company, Germany. In 1986, three plants were operating in Germany. 

Powerclaus A flue-gas desulfurization system which applies the Aquaclaus process to power station effluent gases. 

An application in power production, particularly in coal-fired power plants, is the analysis of flue gas scrubbers which remove excess SO2 following coal combustion. Tests run by SAMBESRL at the EPA s Research Triangle Park facility (8,9) have demonstrated the effectiveness of IC in determining sulfite and sulfate in flue gas desulfurization systems. Table III gives results of direct IC analysis of scrubber liquors compared with turbidimetric and titration methods. 

Elemental Composition of Atmospheric Fine Particles Emitted from Coal Burned in a Modern Electric Power Plant Equipped with a Flue-Gas Desulfurization System... 

Improved control devices now frequently installed on conventional coal-utility boilers drastically affect the quantity, chemical composition, and physical characteristics of fine-particles emitted to the atmosphere from these sources. We recently sampled fly-ash aerosols upstream and downstream from a modern lime-slurry, spray-tower system installed on a 430-Mw(e) coal utility boiler. Particulate samples were collected in situ on membrane filters and in University of Washington MKIII and MKV cascade impactors. The MKV impactor, operated at reduced pressure and with a cyclone preseparator, provided 13 discrete particle-size fractions with median diameters ranging from 0,07 to 20 pm with up to 6 of the fractions in the highly respirable submicron particle range. The concentrations of up to 35 elements and estimates of the size distributions of particles in each of the fly-ash fractions were determined by instrumental neutron activation analysis and by electron microscopy, respectively. Mechanisms of fine-particle formation and chemical enrichment in the flue-gas desulfurization system are discussed. 

In this work, we use a University of Washington low pressure impactor (LPI) and instrumental neutron activation analysis (INAA) to determine the elemental composition of aerosols from a two 430 MWe coal-utility boilers, ranging in diameter from less than 0.07 to about 10 )Jm, and to investigate the modification of the aerosol by a modern flue-gas desulfurization system. A preliminary account of the work is presented here. 

Figure 4. Enrichment factors (relative to Sc) vs. particle size curves for aerosols collected up- and downstream of the flue-gas desulfurization system show considerable concentration enhancement in the submicrometer size region.

We have further applied these techniques to investigate the chemical modification of aerosols by a modern flue-gas desulfurization system. This study confirms our earlier work with a high-energy Venturi wet scrubber system, in which we observed high chemical enrichment of aerosols from evaporative processes. 

Behrens, G.P., G.D. Jones, N.P. Meserole, W.S. Seames, and J.C. Dickerman, "The Evaluation and Status of Flue Gas Desulfurization Systems," Electric Power Research Institute Report No. CS-3322, January, 1984. 

Lee and Rochelle (25) have investigated the effects of various additives on the degradation of carboxylic acids used as buffers in flue gas desulfurization systems, comparing the rates of decarboxylation to sulfite oxidation. It is apparent from Table 3 that, of the S0X radicals, only is likely to react with aliphatic... 

Ondov, J.M., Biermann, A.H., Heft, R.E., Koszykowski, R.F., Elemental Composition of Atmospheric Fine Particles Emitted from Coal Burned in a Modern Electric Power Plant Equipped with a Flue-Gas Desulfurization System. American Chemical Society Symposium Series no. 167, 173-186 (1981). 

Flue Gas Desulfurization Systems andS02 Control, Pub. GS-6121, Electric Power Research Institute, Palo Alto, Calif., October 1988. Mi abstracted bibliography of EPRI Reports and Projects. 

Within the last few years, there have been several instances in which independent brick liners have experienced problems in resisting the effects of wet flue gases. In certain instances the problems have been due to actual deterioration of mortar and/or brick which were subjected to chemical attack by certain constituents of either the flue gas itself or carry over" reagents from the flue gas desulfurization system. In general, the commonly used silicate mortars for chimneys are quite resistant to a wide range of acids and actually thrive in a wet acid environment. However, certain acids, such as hydrofluoric acid, and most... 

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. 

Kelly, M. E. and J. C. Dickerman, "Current Status of Dry Flue Gas Desulfurization Systems", Symposium on Flue Gas Desulfurization, Houston, Texas, October 28-31, 1980, pp. 761-776, EPA-600/9-81-0196. 

The adaptability of this sulfur dioxide reduction technology to a feed gas containing 100% sulfur dioxide (dry basis) will be demonstrated at the D. H. Mitchell Station of the Northern Indiana Public Service Co. (NIPSCO) at Gary, Indiana (8). In this application the process will be combined with the Wellman-Lord sulfur dioxide recovery process to provide a complete flue gas desulfurization system for a 115-MW coal-fired boiler in a project jointly funded by NIPSCO and the Environmental Protection Agency. 

This process is not sensitive to the water balance and has been used to treat off-gas from a molybdenum smelter as well as being installed in two desulfurization plants (one in a flue gas desulfurization system, the other on an industrial boiler) currently under construction. An earlier version of the WCP technology was used to treat lean hydrogen sulfide gases. For all gas feeds, sulfurous components in the gas are converted to sulfuric acid without the need to dry the gas first. 

FIGURE 14.29 Flue-gas-desulfurization process based on lime (CaO) or limestone (CaCOj), sorbents used by many flue-gas-desulfurization systems. 

Frazier, W.F., Gaswirth, H., MongiUo, R.J., Shattuck, D.M., and Wedig, C.P. 1991. Flue gas desulfurization systems designed and operated to meet the clean air act amendments of 1990. Presented at the Industrial Gas Cleaning Institute, Inc., IGCI Forum 91, Washington, DC, September 11—13, TP 91-55. 

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