Glen Tomlinson

Integration of fossil and renewable energy technologies to mitigate carbon dioxide

Abstract This paper analyzes several integrations of photovoltaics (PV) and integrated coal gasification combined cycle (IGCC) technologies to reduce carbon dioxide. In one of these integrations, liquid hydrocarbon transportation fuels are produced by reacting the carbon dioxide from the IGCC plant with hydrogen produced from PV electrolysis of water. This system appears to be cost competitive with a hydrogen economy alternative for future estimates of system performance and costs.

A technical and economic comparison of natural gas and coal feedstocks for fischer-tropsch synthesis

Publisher Summary This chapter investigates the economics of coal-based and natural gas-based plants for the production of high quality liquid transportation fuels, using advanced Fischer–Tropsch (F–T) synthesis. A coal-based plant consists of all the unit operations necessary for a grass-root facility. Coal is gasified using Shell gasification and the cleaned synthesis gas is fed to slurry-phase F–T reactors. The unconverted synthesis gas and the methane, ethane, and ethylene are sent to an autothermal reformer and recycled to the F–T reactors. Plants that produce an all liquid product require that the F–T tail gas be reformed and recycled back to the F–T reactors. This adds a significant cost and efficiency penalty to the process. Although coal may be the preferred feedstock to F–T plants in the future when petroleum and natural gas costs are high, in the shorter term, these plants use natural gas as feed if the gas cost is low. The natural gas must be converted into synthesis gas before F–T synthesis can occur. Conventional steam reforming of natural gas produces a synthesis gas with much higher hydrogen to carbon monoxide ratio than required for F–T stoichiometry.