High efficiency coal-fired power plant of the future

In this work a novel coal fueled power plant, which combines coal gasification and solid oxide fuel cell technology, is presented. The cycle is a modification of an earlier one proposed by the same authors [Lobachyov and Richter, Journal of Energy Resources Technology, 1996, 188]. It retains most of the elements of the previous plant: Conoco CO2 acceptor gasification process, solid oxide fuel cell and state-of-the-art gas turbines. A key difference between the previous and the new cycle is a different heat recovery concept. Instead of using the sensible heat of the cathode exhaust for the coal gasification process, the fuel not oxidized in the fuel cell is burnt to provide this heat. This new concept allows us to simplify the cycle and makes its performance less 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 new cycle achieves a gain in the overall efficiency of more than two percentage points under the same operating parameters. At a maximum system 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.