Recovery and Recycling of Limestone in LEC Flue Gas Desulfurization. Final Report, Third Year

Recovery and Recycling of Limestone in LEC Flue Gas Desulfurization. Final Report, Third Year

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Published: 1993

Total Pages: 31

ISBN-13:

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A potentially attractive flue gas desulfurization method called Limestone Emission Control (LEC) is currently being investigated by Prudich at Ohio University. In this process, beds of 1/8 inch limestone gravel particles absorb sulfur dioxide from flue gas. This forms sulfite and sulfate salts which coat limestone, blinding the surface and limiting utilization to 20%. Favorable economics can be generating when the unreacted portion of the limestone is recovered by mechanical grinding. This project is a wet method for grinding and recovering the spent limestone from the LEC process, utilizing an impeller fluidizer, a new type of slurry processor. It consists of a cylindrical vessel with an impeller at one end. The impeller generates sufficient pressure head to serve as a slurry pump. It combines the operation of wet grinding, washing, and transporting the spent and recovered limestone as an aqueous slurry. The objectives of the first two years were to operate fluidizer in a batch mode to carry grinding experiments, and to determine the removal of the sulfur coatings from the limestone when operating the fluidizer in a continuous mode. The main thrusts of the third year were to complete the grinding data and coordinate the data with reactivity determinations of the recovered limestone. Direct measurement of power requirements, operation of single impeller fluidizer, grinding of surface deposits and other methods of removing surface deposits have also been investigated along with sorption characteristics of recovered limestone, microscopic examination of the limestone surface, and limestone attrition.


Flue Gas Desulfurization and Industrial Minerals

Flue Gas Desulfurization and Industrial Minerals

Author: M. Michael Miller

Publisher:

Published: 1993

Total Pages: 720

ISBN-13:

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Contains 4,101 references on FGD [Flue Gas Desulfurization] ... primarily from 1982 through June 1993. Complements the "Flue Gas Desulfurization and Denitrification" bibliography published by the U.S. Dept. of Energy in Jan. 1985. References were located on the Energy, Science and Technology, Pollution Abstracts, and Environmental Bibliography databases. Primarily covers FGD and the use of industrial minerals in the desulfurization process or in by-product utilization and disposal. Emphasizes post-combustion removal of sulfur dioxide through processes such as in-duct injection and wet and dry scrubbing.


Pilot-scale Limestone Emission Control (LEC) Process: A Development Project. Volume 1, Main Report and Appendices A, B, C, and D: Final Report

Pilot-scale Limestone Emission Control (LEC) Process: A Development Project. Volume 1, Main Report and Appendices A, B, C, and D: Final Report

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Published: 2005

Total Pages:

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ETS, Inc., a pollution consulting firm with headquarters in Roanoke, Virginia, has developed a dry, limestone-based flue gas desulfurization (FGD) system. This SO[sub 2] removal system, called Limestone Emission Control (LEC), can be designed for installation on either new or existing coal-fired boilers. In the LEC process, the SO[sub 2] in the flue gas reacts with wetted granular limestone that is contained in a moving bed. A surface layer of principally calcium sulfate (CaSO[sub 4]) is formed on the limestone. Periodic removal of this surface layer by mechanical agitation allows high utilization of the limestone granules. A nominal 5,000 acfm LEC pilot plant has been designed, fabricated and installed on the slipstream of a 70,000 pph stoker boiler providing steam to Ohio University's Athens, Ohio campus. A total of over 90 experimental trials have been performed using the pilot-scale moving-bed LEC dry scrubber as a part of this research project with run times ranging up to a high of 125 hours. SO[sub 2] removal efficiencies as high as 99.9% were achievable for all experimental conditions studied during which sufficient humidification was added to the LEC bed. The LEC process and conventional limestone scrubbing have been compared on an equatable basis using flue gas conditions that would be expected at the outlet of the electrostatic precipitator (ESP) of a 500 MW coal-fired power plant. The LEC was found to have a definite economic advantage in both direct capital costs and operating costs. Based on the success and findings of the present project, the next step in LEC process development will be a full-scale commercial demonstration unit.


Limestone Scrubbing for 2000 Flue Gas Desulfurization System. Final Report, October 1, 1993--April 1, 1997

Limestone Scrubbing for 2000 Flue Gas Desulfurization System. Final Report, October 1, 1993--April 1, 1997

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Published: 1998

Total Pages: 150

ISBN-13:

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As emission limits for sulfur dioxide from utility coal-fired boilers become lower due to increased regulation and environmental concern around the globe, power generating companies require increasingly cost-effective pollution control technology in order to maintain or reduce the cost of electricity to the end user. Limestone based wet flue gas desulfurization, or WFGD, is the preferred sulfur dioxide removal technology for utilities in the US and worldwide. This is a result of its extensive reference list, lower risks, and lower evaluated overall costs. For more than two decades ABB has supplied WFGD systems and currently has greater than 29,000 MWe of scrubbing capacity in operation. Given the industry's ever-present need for lower costs, ABB funds a continuous research and development program focused on technology advancements that will reduce both capital and operating costs for its customers. As a result of this effort the LS-2 Concept WFGD System was developed through revolutionary design changes in every significant subprocess of conventional WFGD technology. To demonstrate the cumulative effects of all the individual advancements of the LS-2 Concept and to prove the process's viability and cost-efficiency under representative US power plant conditions, the Limestone Scrubbing for 2000 project was initiated. This report is the final submittal to the Ohio Coal Development Office to document the results of this demonstrate project. The four-phase project execution, from the initial design and procurement through erection and extensive testing, proceeded as scheduled and on budget. The project resulted in a successful reference program that illustrates, in detail, the improved efficiencies and costs of the LS-2 advancements.