Effects of sulfur emission controls on the cost of gasification combined cycle power systems. Final report

Economic evaluations were performed for a series of coal gasification-combined cycle power generation facilities, each differing in the mode of operation of the sulfur removal unit. The objectives of the study were to determine the added cost of power associated with more stringent sulfur emission requirements as well as the economic impact of the pressure level at which sulfur removal unit was operated. Similar gasification and power generation facilities were used for each evaluation. Identical Texaco type, oxygen-blown, entrained gasifiers were used for all cases. All were integrated with an advanced combined cycle power generation plant based on a design by Westinghouse. The sulfur removal process in each case was Allied Chemical's proprietary Selexol physical solvent process. The mode of operation of the Selexol Unit was varied to achieve a moderate level of sulfur removal at 350 psig and at 1150 psig. Operation to achieve a very ''deep'' level of sulfur removal at 350 psig was also evaluated. The ability to currently achieve the emission requirements specified in the deep sulfur removal case was found questionable, and it was concluded that further development work is necessary. Barring development problems, the cost of power at the stricter emissions level was estimated as 7 to 8% higher than at moderate levels. The economic advantage of high pressure sulfur removal operation was concluded to be insignificant in the cases presented.