Nirmal V. Gnanapragasam

Partial Gasification for CO2Emissions Reduction

From the perspective of energy security and environmental sustainability, highly effective uses for fossil fuel in energy industries are demanded. Power plants having integrated gasification combined cycle (IGCC) with advanced configurations are being developed worldwide to use coal and biomass more efficiently and thus cleanly. Gasification forms the major component within the IGCC systems and has the best fuel flexibility of any of the advanced technologies for power production, with the current technology well adapted to use biomass and other low-value feedstock that have high-ash residues (Liu and Niksa, 2004). Gasification also provides an opportunity to control and reduce gaseous pollutant emissions, and a lowest cost approach to concentrate the carbon dioxide at high pressure to facilitate sequestration (Trapp, 2005).

Exergy Analysis of an Indirectly-Fired Combined Cycle Power Generation System

A natural gas fired combined cycle power plant with indirectly-fired heating for additional work output is investigated in the current work. The mass flow rate of coal for the indirect firing mode in circulating fluidized bed combustor is estimated based on fixed natural gas input to the topping combustor. The effects of pressure ratio, gas turbine inlet temperature, inlet temperature to the topping combustor on the exergetic performance of the combined cycle configuration are analysed. The use of coal in indirect-firing mode reduces with increase in turbine inlet temperature due to increase in the use of natural gas. The exergetic efficiency increases with pressure ratio up to the optimum pressure and it also increase with gas turbine inlet temperature. The exergy destruction is highest for the circulating fluidized bed combustor (CFBC) followed by the topping combustor. The analyses show that the indirectly fired mode of the combined cycle offers better performance but with higher exergy destruction and the opportunity for additional net work output by using solid fuels (coal in this case) in existing natural gas based power plant is realized.Copyright