Simultaneous SOx/NOx/Particulate Removal in a High Temperature Baghouse

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PAPER NO. 23 Simultaneous SOx/NOx/Particulate Removal in a High Temperature Baghouse K. E. Redingf, P. ChUt G. A. Farthing. and S. J. Vecci The Babcock & Wilcox Company - Research and Development Division Alliance. Ohio 4460 1 J. M. Wilkinson The Babcock & Wilcox Company - Environmental Equipment Division Barberton t Ohio 44203 R. W. Corbett U.S. Department of Energy - Pittsburgh Energy Technology Center Pittsburgh. Pennsylvania 15236 ABSTRACT The SOx-NOx-Rox BoxThi (SNRB) process is a Babcock & Wilcox (B&W) patented advanced air pollu­tion control system that provides for significantly reduced SOx' NOx' and particulate emissions from coal-frred boil­ers. The process utilizes a high-temperature catalytic baghouse for the integration of SOx reduction through the injection of an alkali sorbent such as hydrated lime or so­dium bicarbonate. NOx removal through ammonia injec­tion and selective catalytic reduction. and particulate col­lection. The advantages of the process include: compact integration of the emission control technologies into a single component. dry sorbent and by-product handling. and improved SCR catalyst life due to lowered SOx and particulate levels. Emission control performance of the SNRB concept has been successfully demonstrated in an integrated. 1500 ft3/minute capacity pilot baghouse at B&W's Alli­ance Research Center. The test results have been used to develop design. performance. and operating specifications for a 5 MW e demonstration facility currently under con­struction at a commercial utility site. The facility will be used to generate information needed for commercializa­tion of the SNRB technology. INTRODUCTION B&W's patented SOx-NOx-Rox-Box process - also known as SNRB - has been developed to provide boiler operators with a cost-effective way to simultaneously con­trol their emissions of particulate matter (Rox) and the oxides of sulfur (SOx) and nitrogen (NOx)' Briefly. the process (shown in Figure 1) comprises the injection of both ammonia and dry sorbent upstream of a fabric filter (baghouse). A catalyst for the selective catalytic reduc· tion (SCR) of NOx is mounted inside the filter bags. pro­viding for the destruction of NOx as the flue gas/ammonia mixture passes over the catalyst. SOx is absorbed by the sorbent both in the flue gas duct, and as the sorbent resides on the filter bags in the baghouse. Since the SOx and NOx removal processes require operation at elevated gas tem­peratures (550· - 900·F). specially woven high-tempera­ture fabric filter bags are used. HIGH -TEMPERATURE CERAMIC BAG ALKALI INJECTION INLET FLUE GAS • NOI • SOl • PARTICULATES Figure 1. SOx-N0x·Rox-Box Process lASH ~ CLEAN FLUE GAS CATALYST