Fixed bed coal gasifiers integrated with MCFC-GT hybryd systems for distribuited power and heat generation

COCCO, DANIELE;SERRA, FABIO;TOLA, VITTORIO

2008-01-01

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Abstract

In this paper, a performance assessment of coal gasification processes integrated with molten carbonate fuel cells (IG-MCFC) is reported on. The main aim of the study was to evaluate the performance of small and medium size IG-MCFC systems based on fixed-bed gasifiers for distributed power and heat generation. In particular, the plant configuration considered here was developed on the basis of the 700 kg/h fixed-bed up-draft coal gasifier located in the Sotacarbo Research Centre in Carbonia, Italy. The MCFC section is based on the DFC/T® hybrid system developed by FCE Inc., and includes a MCFC stack integrated with an indirectly heated gas turbine. Two different coals, namely a low and a high sulphur coal, were considered. Moreover, the performance of MCFC hybrid systems fuelled by natural gas and coal gas were also compared. The results of the performance assessment show that the optimum value of the gas turbine pressure ratio is around 3, which is very similar to that used by the DFC/T systems proposed by FCE Inc. and fuelled by natural gas. However, replacing methane with coal gases leads to a significant decrease in MCFC efficiency, on the order of 10-11 percentage points. On the whole, the performance assessment carried out in this paper demonstrates that IG-MCFC systems could be an interesting option for small- and medium-size power generation plants fuelled by coal as they can reach efficiencies of nearly 40%.