Production of hot, saturated fuel gas

Claim 1

In apparatus for the production of a low BTU fuel gas stream comprising in combination a coal gasifier and, thereafter in sequential flow communication therewith, means for adding water to the product gas stream from said coal gasifier to reduce the temperature thereof; heat exchange means for further reducing the temperature of said product gas stream sufficient to condense water therefrom; means for reducing the hydrogen sulfide and ammonia content of said product stream; and means for reheating said product stream and increasing the water vapor content thereof by means of a hot liquid, the improvement in which the means for reheating the product stream and increasing water vapor content thereof comprises in combination: an enclosure; means disposed in said enclosure for defining two separate flow volumes therein; means connected to said enclosure for admitting a first fluid flow into one of said flow volumes; means connected to said enclosure for removing first fluid flow from said one flow volume; means connected to said enclosure for admitting a second fluid flow into the other of said flow volumes; and means connected to said enclosure for removing second fluid flow from said other flow volume; said defining means being formed at least in part as a microporous barrier; said microporous barrier being made of a material selected from the group consisting of hydrophobic polymer material and hydrophilic polymer material having a gel structure.