Novel technologies for SO{sub x}/NO{sub x} removal from flue gas; Technical report, September 1--November 30, 1993

The goal of this research is to develop a low temperature deNO{sub x} catalyst with activity high enough for boiler retrofit applications. Cu-ZrO{sub 2} is a promising low temperature catalyst for the selective reduction of No by propene. At NO = 1000 ppm, propene (C{sub 3}H{sub 6}) = 1000 ppm and 0{sub 2} = 1% and a space velocity of 13,000 h{sup {minus}1}, the NO conversion to N{sub 2} is 64% at 265{degrees}C. The performance of the catalyst, however, does not fulfill the requirement when used for flue gas clean up where the feed is composed of 4% O{sub 2} and 10% H{sub 2}O, and the temperature is 150{degrees}C. Methods to improve the performance of the catalyst are being sought. These include modification of the preparation method such as varying the aging time of the gel after precipitation, and addition of promoters like Pd and Nd to increase the catalytic activity at lower temperatures and higher 0{sub 2} concentrations. Using ethanol (C{sub 2}H{sub 5}OH) instead of C{sub 3}H{sub 6} as a reductant improves the performance of the catalyst when H{sub 2}O is present. Interestingly, methanol is not an effective reductant. Some modified carbon catalysts are also tested. Results on Cu impregnated ASC whetlerite carbon catalyst show 100% N{sub 2} selectivity and 35 % NO conversion at 200{degrees}C. However, the catalyst is unstable and deactivates rapidly. Work planned for the next quarter is to continue to investigate methods to improve the catalytic activity