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Show Through the integration of the SOx, NOx, and particulate removal processes into a single unit, lower capital cost and space requirements are achieved, and operating procedures are simplified, when compared to a conventional emissions control system comprising separate wet scrubber, SCR, and particulate removal systems. B&W is currently conducting a multi-phase project funded by the U.S. Department of Energy (DOE) - PETC, the Ohio Coal Development Office (OCDO), and the Electric Power Research Institute (EPRI) under the DOE's Innovative Clean Coal Technology program. The objective of the B& W project is to continue the commercial development of the SNRB concept in a 5 MWe field demonstration unit currently under construction at Ohio Edison's R. E. Burger Station located near Shadyside, Ohio. Other members of the project team include Ohio Edison (host utility), Norton Company (catalyst supplier), and Minnesota Mining and Manufacturing - 3M (bag supplier). The minimum emission control targets for the project include the cost-effective reduction of SOx. NOx. and particulate emissions in the following manner: • 70% SOx removal • 90% NOx removal • Particulate emissions in compliance with the New Source Perfonnance Standards (NSPS) - 0.03 lb/ million Btu Phase I - Design and Penniuing - of the program involved the development of a detailed engineering design for the 5 MW e SNRB facility , and the preparation of the required environmental and pennitting documents. The design activities were supported by the operation of a 1500 ft3/minute SNRB laboratory pilot unit located at B&W's research center in Alliance. Ohio. Installation of NH. SUPPlY BOILER BOTTOM ASH Figure 2. CommercialSNRB Application ECONOMIZER OUTlET 2 the 5 MW e facility (now nearing completion) is being carried out under Phase II - Procurement, Installation, and Startup. Following startup and shakedown activities in late 1991, full operation of the facility will begin in January 1992. A 7 -month testing program will follow, wherein detailed operating and perfonnance data will be generated over a wide range of operating conditions. The test work will be conducted as pan of Phase III - Demonstration Operation and Restoration - of the program. This paper is intended to provide a summary of the status of the development of the SNRB technology. SNRB PROCESS DESCRIPTION The SNRB process comprises a single process unit - a pulse-jet fabric filter (baghouse) -located upstream of the boiler's combustion air preheater and operating at a temperature 550· - 900·F. One possible arrangement of the SNRB process applied to a utility boiler system is illustrated in Figure 2. A specially woven ceramic fabric is used for the fabrication of the filter bags to pennit reliable baghouse operation at these elevated temperatures. Absorption of SOx is accomplished through the injection of a finely divided dry alkali sorbent into the flue gas stream upstream of the baghouse. The SOx in the flue gas reacts with the sorbent while the latter is dispersed in the flue gas stream as it flows through the ductwork and baghouse, and while it resides on the filter bags in the fonn of ruter cake. A catalyst for the selective catalytic reduction (SCR) of NOx is installed inside the filter bags - the clean side of the bags in a pulse-jet baghouse. By injecting ammonia into the flue gases upstream of the baghouse, NOx is convened to hannless N2 and H20 as the gases pass over the catalyst. Particulate matter - fly ash and spent sorbent - is removed as flue gases pass through the filter bags. STACK |