HIGH-EFFICIENCY COAL-FIRED POWER-PLANT OF THE FUTURE

In this work a novel coal fueled power plant, which combines coal gasi fication and solid oxide fuel cell technology, is presented. The cycle is a modification of an earlier one proposed by the same authors [Lob achyov and Richter, Journal of Energy Resources Technology, 1996, 188] . It retains most of the elements of the previous plant: Conoco CO2 ac ceptor gasification process, solid oxide fuel cell and state-of-the-ar t gas turbines. A key difference between the previous and the new cycl e is a different heat recovery concept. Instead of using the sensible heat of the cathode exhaust for the coal gasification process, the fue l not oxidized in the fuel cell is burnt to provide this heat. This ne w concept allows us to simplify the cycle and makes its performance le ss dependent on the pressure drop in different components of the cycle . Further, it considerably reduces the exergy loss in the gas turbine by eliminating exergetically inefficient turbine blade cooling. The ne w cycle achieves a gain in the overall efficiency of more than two per centage points under the same operating parameters. At a maximum syste m pressure of 10 bar and an anticipated solid oxide fuel cell voltage of 0.7 V the overall thermal efficiency is approximately 63%. (C) 1997 Elsevier Science Ltd.