All calculations were based on a typical internationally traded coal of which the properties are given in Table E1. All flow schemes are based on 100 kg maf coal, and the relevant mass and energy values are all based on this quantity. Taking the mass values per second, we get the energy flows in MW.

For drying the coal from 12.5% to 2% moisture, 31 MJ _th are required. As this heat is supposed to be supplied by burning part of the clean fuel gas, this corresponds to an energy penalty of about 19 MJ _e.

For heating the water for the optimal coal-water slurry feed gasifier to 325 C, 121 MJ _th/100 kg maf coal are required.

For a classical GEE gasifier, the carbon conversion has been set at 95%. In all other cases, this has been set at 99%.

The energy required for the production of oxygen was taken as 46 MJ _e/kmole. If not indicated otherwise, the purity of the oxygen is 95% mole.

For making 300 C process steam for dry coal feed gasifiers, 3 MJ _th/kg are required.

The heat loss from the gasifiers has been taken as 0.5% of the coal LHV for the coal-water slurry feed gasifiers, and as 2% of the coal LHV for the dry coal feed gasifiers. In the latter case, it has been assumed that this heat is available for making steam.

For all compressors and turbines, a polytropic efficiency of 90% has been assumed. For...