A novel carbon-based process for flue gas cleanup. Fifth quarterly technical progress report, July 1--September 30, 1992

Abstract

The objective of this project is to demonstrate the preliminary technical and economic feasibility of a novel carbon-based process for removal of at least 95% S0{sub 2} and at least 75 % NO{sub x}, from coal combustion flue gas. In the process, flue gas leaving the electrostatic precipitator (ESP) is passed through a trickle bed of activated carbon catalyst employing a periodic flush of low strength sulfuric acid. The S0{sub 2} is oxidized to S0{sub 3} and removed as medium strength sulfuric acid. The S0{sub 2}-free flue gas is then mixed with NH{sub 3}, and the NO{sub x} in the gas is subjected to selective catalytic reduction (SCR) to N{sub 2} over a fixed bed of activated carbon catalyst. In the previous four quarters, a detailed project management plan was prepared describing the experimental setup, work plan, and test plan. The experimental system was completed for SO{sub 2} conversion at Waterloo and for NO{sub x} conversion at Research Triangle Institute. Shakedown experiments were completed. The NO{sub x} removal performance of two additional modified carbon catalysts (MCCII and MCCIII) was studied. MCCII showed NO{sub 2} removal efficiency which was similar to that observed for MCCI. However, MCCIII was considerably less active for NO{sub x} removal. In the present quarter, further tests of MCCI were performed for SO{sub 2} removal with NO in the feed gas, except the reactor was operated at 130{degrees}C (instead of 80{degrees}C during previous tests). Tests were also performed with MCCII for NO removal with nominally 100 ppm SO{sub 2} in the feed gas.