Application of Fuel-Cell-Based Power Installations at Thermal Power Plants

The feasibility of using fuel-cell-based power installations (FСBPI) in auxiliary power (AP) systems at thermal gas/oil or gas-fired power stations is discussed. In this case, two options can be implemented at once: replacement of some district water heaters at a thermal power plant (TPS) with heaters using the heat of reaction products in FСBPIs and parallel power generation by TPS with the Rankine cycle and FСBPI. A thermodynamic analysis has demonstrated an increase in the thermal efficiency of TPSs since an FСBPI complex increases power delivery to a power system. Calculations were performed for a 300-MW power unit at a condensing power station (CPS). In particular, the installed capacity of FСBPIs was considered assuming that its thermal output is equal to the thermal output of network water heaters. In this case, additional power generation by the TPS power unit proper amounts to 50 632.8 MW h. Gas is supplied to the CPS power unit and FСBPIs from the same system. It is demonstrated that construction of such a complex is feasible if the FСBPI efficiency is higher than the net efficiency of the CPS power unit. This also yields natural gas saving throughout a year. The payback of the proposal for the use of FСBPIs is based on an increase in the KPS power output due to an increase in the thermal efficiency and the fact the FСBPIs deliver additional power (minus the auxiliary power) to the power system. In addition, turbine steam extraction to network water heaters and the generator power take-off to cover auxiliary power needs are eliminated. Therefore, according to the simplified calculations, the payback period for 25 MW FСBPIs operating on natural gas as a part of a 300-MW gas-fired CPS is approximately 2 years. The maneuverability of the CPS increases considerably within the FCBPI’s installed capacity.