DEVELOPMENT OF A HIGH-TEMPERATURE CERAMIC-TO-METAL SEAL

Research is currently being conducted into the construction of high-te mperature (>1000 degrees C) tubular heat exchangers that are to operat e with a large pressure differential between low-pressure combustion g as and a process fluid. High operating temperatures preclude the use o f metals. Therefore it is necessary to use ceramic heat transfer compo nents and to insulate other components to counteract the direct heat. As the high-temperature ceramic heat transfer tubes exhibit a variable thermal expansion relative to the outer metallic casing and tube shee t, it is necessary for the seals to slide. This prevents excessive axi al stress being set up in the ceramic tubes, thus prolonging their lif e.