Commercial application in high-efficiency FGD of sorbent injection with flue gas humidification

The paper updates the commercial progress in the recent development of a low-capital-cost method of achieving high efficiency (85--90%) removal of SO{sub 2} from high-sulfur fossil fuel combustion. The results of the successful performance of a proof-of-concept, field pilot plant operation in Izmir, Turkey are presented. In addition, details of the design of the first commercial scale, high-performance installation of dry sorbent injection, now underway in Turkey, is described. Superior performance and cost-effectiveness are shown to be achieved by employing unique, linear nozzle-lances for integrating, in the same device, the injection of alkali-enhanced, dry hydrated lime and the fine atomization of water required for effective gas cooling and sorbent surface wetting. The high efficiency is achieved via a comparatively rapid and complete intermixing of the flue gas and the enhanced-reactivity sorbent, surface-wetted by the fin spray droplets as the flat, parallel plumes containing droplets and powdered reagent intermix in the vicinity of the nozzle. The fine atomization also enables a close approach (of the cooled-gas dry bulb temperature) to the gas-stream wet bulb temperature with evaporation to dryness, thereby permitting the recycle of partially spent sorbent for enhanced lime utilization and mass transfer, lower-cost operation and reduced wasted generation. Uniquelymore » fine atomization has enabled the use of economically-sized spray towers in both the field pilot plant and commercial plant installations. This is essential when plot space is limited or when an alternative, long, horizontal duct required for complete spray water evaporation, (and the attendant, high, gas-stream velocity), would not be feasible in plant retrofits or new plant designs. The method and designs described in the paper are shown to have broad application in low- and high-sulfur fuel combustion. They offer an advancement in the use of dry sorbent injection in conjunction with fabric filtration in the retrofit of older and smaller U.S. domestic generating plants. They will also help support the current growth in the use of diesel engine and gas turbine plants fueled by low-cost, high sulfur residual oil available in the Middle East.« less