Baghouse Slipstream Testing at TXU's Big Brown Station

Abstract

Performing sorbent testing for mercury control at a large scale is a very expensive endeavor and requires months of planning and careful execution. Even with good planning, there are plant limitations on what operating/design parameters can be varied/tested and when. For parameters that cannot be feasibly tested at the full scale (lower/higher gas flow, different bag material, cleaning methods, sorbents, etc.), an alternative approach is used to perform tests on a slipstream unit using flue gas from the plant. The advantage that a slipstream unit provides is the flexibility to test multiple operating and design parameters and other possible technology options without risking major disruption to the operation of the power plant. Additionally, the results generated are expected to simulate full-scale conditions closely, since the flue gas used during the tests comes directly from the plant in question. The Energy & Environmental Research Center developed and constructed a mobile baghouse that allows for cost-effective testing of impacts related to variation in operating and design parameters, as well as other possible mercury control options. Multiple sorbents, air-to-cloth ratios, bag materials, and cleaning frequencies were evaluated while flue gas was extracted from Big Brown when it fired a 70% Texas lignite-30% Powder River Basin (PRB) blend and a 100% PRB coal