| 摘要 |
The present invention is directed to a method for recovering heat from a gas stream contaminated with water vapor and an acid-forming moiety, said gas having an acid dew point ranging from about 200 DEG F. to 300 DEG F. and a water dew point ranging from about 90.20 F. to 150 DEG F. The inventive method comprises passing the gas stream through a heat exchange fitted with a plurality of generally-parallel tubes through which flow heat exchanging fluid counter-current to the flow of said gas stream in said heat exchanger. The heat exchanging fluid is at a temperature such that the exterior tube temperature is at or below both said dew points, or the temperature of the contaminated gas stream exiting the heat exchanger is at or below both said dew points. The tubes are formed from acid-resistant, resin-impregnated graphite and exhibit a smooth, washable exterior surface. The heat exchanger further is fitted with a pair of side apertured tube sheets through which said tubes penetrate. The ends of the tubes penetrating through the tube sheets are interconnected with non-graphite connectors for establishing a flow path of heat exchange fluid therethrough. The tube sheets house an interior heat-exchange chamber therebetween through which said contaminated gas stream flows.
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