Modular coal-fired FBC cogeneration

The general conception among energy users is that coal-fired cogeneration in the 25,000 to 80,000 pph range is not financially attractive. This article describes an approach developed to allow the use of coal or waste as a fuel in this market. The design approach focuses on modular design, multifuel capability and inherent emissions control. While these three areas are all important, the prime considerations from an industrial viewpoint are economic considerations and risk assessments. The use of coal as a fuel, and especially of cogeneration, requires a larger capital investment, however this article shows that coal-fired cogeneration will actually reduce the overall energy cost for most plants presently burning gas. In addition to steam generation with gas, other thermal cycles are available, the two most common being gas-fired steam cogeneration and gas-fired gas turbine cogeneration. In conclusion it is pointed out that FBC coal-fired cogeneration can be cost-effective in the 25,000 to 80,000 pph range; that there is little risk associated with selection of FBC coal firing as opposed to conventional gas firing although a careful analysis during the preliminary design is necessary for selection of the best option, and that selection of financing alternatives will dramatically affect the IRRmore » and discounted cash flows.« less