Cogeneration Design Considerations for a Major Petrochemical Facility

Abstract

The step increase in energy cost brought about in 1973 has permanently changed the way in which petrochemical production facilities are designed, operated, and maintained. Highly visible energy conservation programs consisting of steam trap repair, insulation, and turning off unused equipment in the late 1970’s gave way to industrial wide shutdown of older, less efficient production facilities in the 1980’s. The subject petrochemical facility’s energy use peaked in early 1981. Several small projects were instituted to accommodate a declining steam load and increasing amounts of low pressure steam venting. However, as steam load was dropping, electrical rates were increasing both from rising natural gas costs and utility construction of a nuclear power plant. As a result, energy costs seemed almost an uncontrollable cost in late 1982. This paper addresses the design considerations and the following distinct steps taken in the development process of a 100 megawatt cogeneration power plant currently under construction at the petrochemical facility. The paper addresses the following distinct steps taken in the design process. 1. Examination of past, current, and future electricity and steam demand. 2. Examination of the regulatory climate and opportunities for firm power sales. 3. Economic evaluation of different fuel and power cost projections and their impact on cycle and equipment selection. 4. Evaluation of the reliability required by current and associated future standby power contracts. 5. Examination of outside forces that impact the design. 6. Selection of final design. The above considerations led to a unique efficient design that incorporates 100% steam condensing capability and independent dual train operating capability. The subject cogeneration plant is scheduled to be in full operation in December of 1987.