Simpson Paper Co.: First 35MW IM5000 in Cogeneration Plant

In order to reverse the rising cost of energy, in 1983 Simpson Paper Company installed a 35MW IM5000 gas turbine generating unit exhausting into a supplementary fired, three-pressure (HP, IP, LP) boiler at its Shasta Pulp & Paper Mill in Anderson/Redding, California. This first U.S.-based IM5000 was chosen for Simpson’s cogeneration plant because the steam-producing capability of its exhaust gas most nearly matches the mill’s steam load and because of the relatively high proportion of energy output which is converted to electrical power versus exhaust gas energy for steam production. By operating at a compression ratio of 30:1 and a base load firing temperature of 2100 F. (1149 C.), the plant achieves a simple-cycle efficiency in excess of 36%, including the burden of water injection for emissions control. In addition to the IM5000 gas turbine and the heat recovery boiler, the plant utilizes the following features which enable it to meet the special requirements of the Shasta Mill: (1) evaporative cooler - to reduce inlet temperature and increase power as much as 20% in the hot, dry Shasta Mill environment, (2) exhaust gas damper and duct burner - to match steam production to mill demand, (3) high pressure design of the IP and LP drums - to enable these drums to be bottled when HP steam demand is high and LP and IP demand is low, and (4) water injection system - to meet stringent federal and northern California NOx standards. Based on 1983 fuel and power costs, Simpson Paper Company expects a simple payback of approximately three years on the $18.5 million investment in its cogeneration plant. The plant began continuous round-the-clock operation on May 22, 1983.