Salt Grass Combined Cycle: A Major Milestone
Although not built as a Dow-owned facility, the 300MW Salt Grass Combined Cycle plant, using four W501 units (one W501Aunits and three W501AA units), was built as a dedicated power supply for Dow’s expanding operaitons in Freeport. The plant was designed, built, and owned by Power Systems Engineering (PSE) from 1970 to 1972. PSE was later incorporated into DESTEC Energy after being acquired by Dow in 1989. DESTEC later morphed into Dynegy, a major independent power generating company.
Unlike most industrial generating plants, there was to be no process steam requirement for the Salt Grass plant; all output from the plant was to be in the form of electric energy. The design objective was to use the largest gas turbines available and, based on prior experience, to use unfired heat recovery boilers for operating simplicity and improved reliability. All steam was used to drive four identical 25MW steam turbines coupled to the gas turbines at the outboard end of the generators, which in turn, were mounted on the cold compressor-end of the gas turbine. The plant comprised four separate single-shaft combined cycle units for maximum operating flexibility. It also included a start-up boiler to enable the steam turbines to be used to start the gas turbines.
Construction of the Salt Grass plant began in January of 1970 and the first gas turbine unit was operational 12 months later, according to a joint PSE-Dow paper presented at the time. Westinghouse records show that he fourth gas turbine was in commercial operation early in 1972, so the entire plant was completed in just over two years.
PSE was founded by two ex-Westinghouse engineers from the field sales office in Houston, Texas: Sales Engineer Tom McMichael and District Manager Al Smith. As such, both had a unique relationship with Dow and had been instrumental in previous Westinghouse business with Dow. According to a paper co-authored by Smith in 1971, the idea for the plant was conceived by PSE and Dow in early 1969. The Salt Grass plant was their first venture after they decided to go out on their own.
Dow Chemical was among the most important customers for Westinghouse gas turbines in the years before the electric utility market took hold. As in all such cases, customer rapport, particularly with Dow’s power engineers, were absolutely critical throughout the long history of the Dow-Westinghouse relationship. In the early days, Bert Dykes and Tom McMichael and their District Manager, Al Smith, handled local customer contacts. Don Jones was the primary sales/contract interface for the Small Steam & Gas Turbine Division in Lester, Pennsylvania. Among the key Westinghouse engineers, who worked closely with Dow on the early installations, were Joe Yindra, Joe Citino, Bob Yannone, Joe Ross, and Art Willinbrock. The lead W301/501 engine design engineer was Augie Scalzo, who started his 40-year career at Westinghouse with the Aviation Gas Turbine Division in 1953.