A leak-proof plate-fin heat exchanger concept for process plant applications

Over the last four decades, plate-fin heat exchangers have been used extensively for aerospace applications, their major attributes being compact size, lightweight overall assembly and high reliability. Several million units have seen service for a wide range of fluids, including operation at high temperature and pressure, and clearly a well established technology base exists. Within the process industries, the heat exchanger trend is towards units of smaller size and weight, and lower cost, and the utilization of the plate-fin type of construction is viewed as being in concert with these goals. Recognizing that there are applications involving dissimilar fluids, where an internal heat exchanger leak could result in a hazardous condition, a leak-proof concept to avoid this is discussed in this paper. For a plate-fin heat exchanger of brazed construction, this is achieved by means of a double headering bar system and a buffer layer between the two fluids. Online monitoring of heat exchanger integrity can be achieved by monitoring a small continuous purge flow in the buffer interspace. The process industry can benefit from a well established aircraft heat exchanger technology base that exists for this type of compact leak-proof heat exchanger.