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Show Flue Gas Treatment. In May 1978, two programs were initiated for the development of N0X flue gas treatment for coal-fired systems. One program is for N0X control using Hitachi Zosen's process which is based on selective catalytic reduction of NG^ with NH3. The process utilizes a metallic honeycomb catalyst arrangement for coal-fired applications. The reactor is located between the boiler economizer and the air preheater and in front of any particulate control device. The reaction temperature is in the range of 350- 420°C. The pressure drop is about 200-500 Pa. For 90 percent N0X reduction, a NH3:N0 mole ratio of 1:1 is used. The process will be evaluated in a 2000 Nm3/hr (0.5 electrical MW) pilot plant scale coal-fired source. The host site for the pilot plant will be Georgia Power Company's Plant Mitchell near Albany, Georgia. Flue gas will be obtained from Unit 3, a pulverized coal-fired Combustion Engineering boiler with a nameplate rating of 125 MW. The second program for simultaneous S02/N0X control is evaluating the UOP-Shell process. Briefly, the process employs two or more parallel passage reactors using CuO as the sorbent for SO2, and CUSO4 as the catalyst for the reduction of N0X with NH. A multiple reactor arrangement is needed to allow regeneration of CuSO^ to CuO. Hydrogen is used as the reductant. The reactors are located between the boiler economizer and the air preheater and in front of any particulate control device. The process operates at a temperature of 400°C during both acceptance and regeneration cycles. The cycles will be controlled for 90 percent removal of both N0X and S02« For 90 percent N0X reduction, a NH3:N0 mole ratio of 1:1 is used. The process also will be evaluated in a 2000 Nm^/hr pilot plant coal-fired source. An existing pilot plant, previously used by UOP to evaluate SO2 removal, will be modified for simultaneous removal of N0X and S02* The host site for the pilot plant will be Tampa Electric Company's Big Bend Station in North Ruskin, Florida. Flue gas can be obtained from Unit 1 or 2 which are Riley-Stoker pulverized coal-fired boilers with a nameplate rating of 400 MW each. TVA has performed a preliminary economic evaluation of N0X and N0x/S0x flue gas treatment processes for EPA. The base case was a new, 500 MW power plant burning 3.5% sulfur coal and emitting 600 ppm N0X in the flue gas. The total capital investments and annual revenue requirements for three dry N0X 3-49 49 |
