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Development of a regenerative fluidized-bed process for simultaneous removal of SO, and NO, from flue gas has been underway at the Pittsburgh Energy Technology Center(PETC) since the late 1960's. In 1970, McCreaet d. [I] reported on the bench-scale evaluation of SO, removal using copper-impregnated alumina spheres and presented preliminary design criteria for a process to be used to treat flue gases from a 1000-MW utility boiler burning a 3%-sulfur coal. A copper-impregnated UOP alumina sorbent, containing 6.3 wt.% Cu, was tested over 200 cycles of SO, absorption arid regeneration with CH, in a fixed-bed bench-scale reactor. No deterioration of the physical or chemical properties of the sorbent was observed during these tests.Fluidized-bed testing(& PETC) ofthe same sorbent material was begun in 1975 using a 6-inch (15.2-cm)-diameter reactor, and the initial results were reported by Strakey et al. [Z]. The tests were conducted with the combustion products of natural gas, spiked with SO,. The SO, removal was measured as a function of solids feed rate, bed height (18 inches and 36 inches; 0.457 m and 0.914 m), and bed temperature (662°F and 750°F or 350°C and 400°C); 75 absorption-regeneration cycles were completed. During several cycles, ammonia was injected for the simultaneous removal of NO,.The results of this study were sufficiently promising to merit continued development of the process. In addition to a continuing evaluation of repeated sorptiodregeneration cycles on sorbent activity, the test program included the following: a determination of the effect of NHJNO, mole ratio on simultaneous removal of SO, and NO,; measurement of ammonia "slip" (unreacted ammonia); in situ measurements of sorbent attrition occurring in t h e fluidized bed; and an evaluation of the effect of fly ash addition on reactor performance. The results of these successful tests were reported at the 1982 Summer National Meeting of the AIChE in Cleveland , Ohio [3].Based on the results ofthe previous research, a 3 ft4 inch x 4ftOinchcross-section x 12ftOinch(1.016 m x 1.219 m cross-section x 3.658 m) high fluidized-bed absorber was designed, fabricated, and installed in a 500 lb/hr (2.268 kg/h) pulverized-coal-fired combustion test facility. A 2 ft 6 inch (0.762 m) diameter x 26 ft 0 inch (0.66 m) high regenerator was also constructed to regenerate the spent sorbent from the absorber. The results of tests conducted in this facility are discussed in this report.

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