Preparation Of Copper Oxide Coated Alumina Catalyst-sorbents By Sol-gel Process And The Research Of Simultaneous Removal Of Sulfur Dioxide And Nitrogen Oxide

The regenerative copper oxide processes is a promising technology for simultaneous removal of SO2 and NOX from flue gas which can remove SO2 and NOX simultaneously with high reaction rate while generating no wastes, reducing energy consumption, and the useful by-products decreasing the costs. The high price of aluminium isopropoxide is the main hurdle to commercialize the sol-gel derived CuO/γ-Al2O3 catalyst-sorbents.CuO/γ-Al2O3 catalyst-sorbents were prepared by sol–gel process based on the mechanism of hydrolyzation and polymerization of aluminium isopropoxide, the reaction conditions were optimized by comparing the surface area of catalyst-sorbents prepared at different conditions. The sol-gel-derived sorbents typically have rather high surface areas, uniform pore size distribution, and large pore volume.CuO/γ-Al2O3 has been used as catalyst-sorbent for the simultaneous removal of SO2 and NOX in a fixed-bed reactor to define the sulfation and SCR characteristics of the CuO/γ-Al2O3 catalyst-sorbent. The main results are discribed as follows.(1)8wt%Cu loading sorbents showed superior sulfation performance than the ones with different Cu loading. When the Cu loading is above 8wt%, crystalline CuO is detected.( 2 ) The optimum temperature for sulfation process over CuO/γ-Al2O3 catalyst-sorbent with 8wt%Cu is about 400℃. Above this value, more and more alumina support would sulfate with the increase of temperature.(3)The optimum temperature ranges for NO reduction over the fresh and sulfated CuO/γ-Al2O3 catalysts with 8wt%Cu are found to be around 350℃. The maximum conversion of NO over fully sulfated sol-gel-derived CuO/γ-Al2O3 catalyst is higher than that over fresh catalyst. It has indicated that the SCR activity of the sulfated CuO/γ-Al2O3 catalyst has enhanced compared to fresh CuO/γ-Al2O3 catalyst. (4)In the simultaneous removal of SO2 and NOX process, the optimum NH3/NO molar ratio is found to be 1.2. Above this value, the NO conversion decreases with the increase of NH3/NO molar ratio attributed to the increase of parallel oxidation of NH3 to N2, which leads to the decrease of surface ammonia available to react with NO.Eventually, the economics of CuO/γ-Al2O3 catalyst-sorbents for simultaneous removal of SO2 and NOX is evaluated.