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Title: Theoretical approach for enhanced mass transfer effects in duct flue gas desulfurization processes

Technical Report ·
DOI:https://doi.org/10.2172/5586316· OSTI ID:5586316
 [1];  [2]
  1. Acurex Corp., Research Triangle Park, NC (United States). Environmental Systems Div.
  2. Texas Univ., Austin, TX (United States). Dept. of Chemical Engineering

Novel techniques designed for the enhancement of Ca(OH){sub 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 SO{sub 2} and 60 percent relative humidity, the presence of up to 30-percent initial free moisture significantly increased sorbent reactivity with SO{sub 2}, 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 SO{sub 2} 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 SO{sub 2} 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 SO{sub 2}. Organic buffer additives were tested as potential enhancement of Ca(OH){sub 2} utilization during the DSD process. Bench-scale results suggested that organic acids should be effective additives to enhance SO{sub 2} in slurry if SO{sub 2} absorption was controlled significantly by liquid film resistance. Pilot-plant tests did not demonstrate significant enhancement of Ca(OH){sub 2} conversion during spray drying as a result of buffer additives. Grinding of simulated DSD solids resulted in significant enhancement of Ca(OH){sub 2} reactivity with SO{sub 2}.

Research Organization:
Acurex Corp., Research Triangle Park, NC (United States). Environmental Systems Div.; Texas Univ., Austin, TX (United States). Dept. of Chemical Engineering
Sponsoring Organization:
USDOE; USDOE, Washington, DC (United States)
DOE Contract Number:
AC22-88PC88874
OSTI ID:
5586316
Report Number(s):
DOE/PC/88874-T15; ON: DE92009615
Country of Publication:
United States
Language:
English