Theoretical Approach for Enhanced Mass Transfer Effects in Duct Flue Gas Desulfurization Processes. Topical Report for Task 4, Novel Techniques

Download or read book Theoretical Approach for Enhanced Mass Transfer Effects in Duct Flue Gas Desulfurization Processes. Topical Report for Task 4, Novel Techniques written by and published by . This book was released on 1991 with total page 147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Novel techniques designed for the enhancement of Ca(OH)2 utilization in dry-sorbent injection (DSI) and duct-spray drying (DSD) were investigated in the Long Time Differential Reactor (LTDR), Short Time Differential Reactor (STDR), and 50-cfm pilot plant. At 2000-ppm SO2 and 60 percent relative humidity, the presence of up to 30-percent initial free moisture significantly increased sorbent reactivity with SO2, compared to sorbent with equilibrium amount of moisture. The conversion decreased when the initial free moisture increased beyond 30--50 percent. The initial free moisture content and corresponding level of maximum sorbent conversion with SO2 varied with the surface area of the sorbent. Sorbent moisture capacity tests indicated that agglomeration of damp calcium silicate sorbent was a function of sorbent pore volume. Critical moisture content was increasing with specific surface area. Very little improvement in SO2 removal was obtained by DSI recycle operation downstream of humidification. Significant enhancement was achieved by DSI recycle upstream of humidification. Grinding of DSI solids with and without fly ash resulted in significant increase of surface area and pore volume and resulting reactivity with SO2. Organic buffer additives were tested as potential enhancement of Ca(OH)2 utilization during the DSD process. Bench-scale results suggested that organic acids should be effective additives to enhance SO2 in slurry if SO2 absorption was controlled significantly by liquid film resistance. Pilot-plant tests did not demonstrate significant enhancement of Ca(OH)2 conversion during spray drying as a result of buffer additives. Grinding of simulated DSD solids resulted in significant enhancement of Ca(OH)2 reactivity with SO2.