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Title: Separation of Mercury from Flue Gas Desulfurization Scrubber Produced Gypsum

Abstract

Frontier Geosciences (Frontier; FGS) proposed for DOE Grant No. DE-FG02-07ER84669 that mercury control could be achieved in a wet scrubber by the addition of an amendment to the wet-FGD scrubber. To demonstrate this, a bench-scale scrubber and synthetic flue-gas supply was designed to simulate the limestone fed, wet-desulfurization units utilized by coal-fired power plants. Frontier maintains that the mercury released from these utilities can be controlled and reduced by modifying the existing equipment at installations where wet flue-gas desulfurization (FGD) systems are employed. A key element of the proposal was FGS-PWN, a liquid-based mercury chelating agent, which can be employed as the amendment for removal of all mercury species which enter the wet-FGD scrubber. However, the equipment design presented in the proposal was inadequate to demonstrate these functions and no significant progress was made to substantiate these claims. As a result, funding for a Phase II continuation of this work will not be pursued. The key to implementing the technology as described in the proposal and report appears to be a high liquid-to-gas ratio (L/G) between the flue-gas and the scrubber liquor, a requirement not currently implemented in existing wet-FGD designs. It may be that this constraint can be reducedmore » through parametric studies, but that was not apparent in this work. Unfortunately, the bench-scale system constructed for this project did not function as intended and the funds and time requested were exhausted before the separation studies could occur.« less

Authors:
;
Publication Date:
Research Org.:
Frontier GeoSciences, Inc.
Sponsoring Org.:
USDOE
OSTI Identifier:
929776
Report Number(s):
DOE/ER/84669-1 Final Report
DOE Contract Number:
FG02-07ER84669
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
20 FOSSIL-FUELED POWER PLANTS; 54 ENVIRONMENTAL SCIENCES

Citation Formats

Hensman, Carl, E., P.h.D, and Baker, Trevor. Separation of Mercury from Flue Gas Desulfurization Scrubber Produced Gypsum. United States: N. p., 2008. Web. doi:10.2172/929776.
Hensman, Carl, E., P.h.D, & Baker, Trevor. Separation of Mercury from Flue Gas Desulfurization Scrubber Produced Gypsum. United States. doi:10.2172/929776.
Hensman, Carl, E., P.h.D, and Baker, Trevor. Mon . "Separation of Mercury from Flue Gas Desulfurization Scrubber Produced Gypsum". United States. doi:10.2172/929776. https://www.osti.gov/servlets/purl/929776.
@article{osti_929776,
title = {Separation of Mercury from Flue Gas Desulfurization Scrubber Produced Gypsum},
author = {Hensman, Carl, E., P.h.D and Baker, Trevor},
abstractNote = {Frontier Geosciences (Frontier; FGS) proposed for DOE Grant No. DE-FG02-07ER84669 that mercury control could be achieved in a wet scrubber by the addition of an amendment to the wet-FGD scrubber. To demonstrate this, a bench-scale scrubber and synthetic flue-gas supply was designed to simulate the limestone fed, wet-desulfurization units utilized by coal-fired power plants. Frontier maintains that the mercury released from these utilities can be controlled and reduced by modifying the existing equipment at installations where wet flue-gas desulfurization (FGD) systems are employed. A key element of the proposal was FGS-PWN, a liquid-based mercury chelating agent, which can be employed as the amendment for removal of all mercury species which enter the wet-FGD scrubber. However, the equipment design presented in the proposal was inadequate to demonstrate these functions and no significant progress was made to substantiate these claims. As a result, funding for a Phase II continuation of this work will not be pursued. The key to implementing the technology as described in the proposal and report appears to be a high liquid-to-gas ratio (L/G) between the flue-gas and the scrubber liquor, a requirement not currently implemented in existing wet-FGD designs. It may be that this constraint can be reduced through parametric studies, but that was not apparent in this work. Unfortunately, the bench-scale system constructed for this project did not function as intended and the funds and time requested were exhausted before the separation studies could occur.},
doi = {10.2172/929776},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jun 16 00:00:00 EDT 2008},
month = {Mon Jun 16 00:00:00 EDT 2008}
}

Technical Report:

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  • The 1985 marketing potential of byproduct gypsum from utility flue gas desulfurization (FGD) was evaluated for the area east of the Rocky Mountains using the calculated gypsum production rates of 14 selected power plants. The 114 cement plants and 52 wallboard plants in the area were assumed to be the potential market for FGD gypsum sales. Assuming use of an in-loop forced-oxidation limestone FGD process, the results showed that producing a marketable gypsum was less expensive than disposal by fixation and landfill for many power plants in the area--including all those used in the study. With this savings to offsetmore » freight costs, the power plants could market 4.35 million ton/yr of gypsum (92% of their production), filling 63% of the cement plant requirements and 20% of the wallboard plant requirements. Cement plants are a geographically dispersed market available to most power plants, but able to absorb the production of only a few power plants; wallboard plants are a larger market but power plant location is a more important marketing factor. Other variations of the marketing model indicated that: (1) drying and briquetting had little effect on the marketing potential, (2) sales were reduced 25% when the savings in FGD cost were not used to offset freight costs, and (3) relocation of wallboard plants to sources of byproduct gypsum appeared economically feasible in some cases. 66 references, 27 figures, 27 tables.« less
  • The double alkali/gupsum method of flue gas desulfurization (FGD) was developed to reduce scaling and plugging problems associated with direct lime (CaO) or limestone (CaCO3) systems. One of the first large-scale installations of this process to control SO2 emissions and produce gypsum (CaSO4) was put in operation in 1973 at the Showa Denko plant in Chiba, Japan. By December 1977, 25 systems were operating, all in Japan. The double alkali system is especially applicable in situations requiring high (98 percent) SO2 removal, high availability, and low maintenance. The process is particularly applicable to areas where lime/limestone resources are abundant andmore » where gypsum is a marketable by-product. If it is not marketable, gypsum and fly ash can be used as landfill to form a base with load-bearing capacities sufficient for some construction.« less
  • The objective of this project was to prepare a comprehensive document detailing the technical and economic aspects of the gypsum industry, which could be used as a reference for power utility personnel. Information for the report was sourced from the authors` existing databases of information, as well as an on-line literature search and extensive discussions with a variety of industrial contacts. The resulting document discusses all aspects of the North American gypsum industry from production through to marketing, with a view to potential utilization markets for flue gas desulfurization (FGD) gypsum in traditional applications. The gypsum industries in Europe andmore » Asia are also discussed.« less
  • The paper gives results of pilot-plant tests using a double draw-off crystallizer as the hold tank to improve the gypsum dewatering properties of a forced-oxidation limestone flue gas desulfurization process. A hydroclone was used as the size-classification device for solids separation and fines removal. Compared with a mixed tank crystallizer, the double draw-off crystallizer resulted in a 45% reduction in free moisture within the filter and a 58% increase in filtration rate.