Gas cooler for production of superheated steam

Abstract

A gas cooler and process are provided for the efficient extraction of heat from a hot raw gas stream containing entrained matter from the partial oxidation of a hydrocarbonaceous or carbonaceous fuel, and the simultaneous production of a separate stream of superheated steam. The gas cooler comprises a closed vertical pressure vessel with an upper central outlet through which the superheated steam is removed. A refractory lined hot gas inlet chamber is attached to the bottom of the pressure vessel. A plurality of bundles of helical tubes through which the hot gas flows are spaced in the vessel. The hot gas enters at the bottom of the vessel and the cooled gas leaves at the bottom of the helical coil. A portion of the vessel is filled with boiler feed water so that the bundles of helical tubes are partially submerged. Concurrent and countercurrent indirect heat exchange between boiler feed water and the gas stream takes place in the evaporator section to produce saturated steam. Concurrent and countercurrent indirect heat exchange between the saturated steam and the partially cooled gas stream then takes place in the superheater section to produce superheated steam. Advantageously, the gas cooler may be easily turned up or down with load by opening or closing off at least one of the helical tubes. This may be done by valving located downstream from the gas cooler at the cold end of the gas path.