A combined SO{sub 2} and NO{sub x} scrubbing process
A new wet scrubber process has been developed and undergone preliminary testing to verify the viability of a zero discharge system for SO{sub 2} and NO{sub x} removal. The process combines the Dravo ThioClear{reg{underscore}sign} process with Tecogen's TecoLytic{trademark} process. The integration of these two technologies results a system that removes both SO{sub 2} and NO{sub x} while producing only salable byproducts. These by-products are wall board grade gypsum, magnesium hydroxide and up to 60 weight percent fertilizer grade calcium nitrate solution. Hence, a zero waste, zero discharge wet scrubber system is being demonstrated. The core of the integrated technology consists of two parts. The first part is the ThioClear process. In this process, a highly alkaline magnesium sulfite solution is used to capture the SO{sub 2} in a high velocity (greater than 15 ft/s with a nominal design of 25 ft/s) horizontal scrubber. Once captured, the sulfites are oxidized to sulfates in an oxidizing vessel. The effluent from the oxidizer is reacted with a magnesium-enhanced lime slurry to raise the pH to about 10.5. At this higher pH, 6 to 10{micro} magnesium hydroxide precipitates and 80{micro} or larger gypsum precipitates are formed. Subsequent product purification produces salable gypsum and magnesium hydroxide. The flue gas continues through the high velocity horizontal scrubber passing through the TecoLytic{trademark} section. In this section, high voltage is applied to produce highly reactive excited species. These species interact with the water vapor present to produce hydroxyl radicals while simultaneously oxidizing the NO to NO{sub 2}. The hydroxyl radicals rapidly oxidize the NO{sub 2} to nitric acid which is scrubbed in the second stage of the horizontal scrubber with a calcium nitrate--lime solution. Bench scale tests have shown high potential. A pilot plant facility has been installed at Cincinnati Gas and Electric Company's Miami Fort facility. Pilot tests at the 5 MW scale will be initiated in May 1998. Preliminary data and economic projections of a commercial system will be presented. These projections show the system to be cooperative to and much lower than SCR systems in certain applications. This project is a cooperative effort of the Ohio Coal Development Office, Cincinnati Gas and Electric, Tecogen, Dravo Lime Company.
- Research Organization:
- Thermo Power Corp., Waltham, MA (US)
- OSTI ID:
- 20012956
- Resource Relation:
- Conference: 23rd International Technical Conference on Coal Utilization and Fuel Systems, Clearwater, FL (US), 03/09/1998--03/13/1998; Other Information: PBD: [1998]; Related Information: In: The proceedings of the 23rd international technical conference on coal utilization and fuel systems, by Sakkestad, B.A. [ed.], 1164 pages.
- Country of Publication:
- United States
- Language:
- English
Similar Records
Production development and utilization of Zimmer Station wet FGD by-products. Final report. Volume 1, Executive summary
Advanced ThioClear process testing. Final report