Structural Analysis and Sealing Capacity of Gasketed Plate Heat Exchangers with HNBR and EPDM Rubbers

Abstract

Rubber is an engineering polymer of interest in most industrial sectors. In gasketed plate heat exchangers (GPHEs), these elements comprise gaskets that are responsible for sealing the system under high levels of compression, temperature and pressure. Therefore, it is a necessity to understand how operating conditions affect GPHE structural behavior and sealing performance, regarding rubber materials and features. This work aims at determining GPHE integrity and mechanical characteristics with the aid of sealing performance experiments and strain gauge measurements at critical plate locations in a real equipment and in prototypes consisting of GPHE components. Hydrogenated Nitrile Butadiene Rubber (HNBR) and Ethylene-Propylene-Diene Rubber (EPDM) gasket materials were evaluated. Based on compression strength experiments, the effects of the number of plates and the compression level on the system stiffness in the direction where the quasi-static compression load is applied have been determined. Stable compression strength behavior was attained with prototypes containing six gaskets or more. The combined effects of pressure load and compression levels, and rubber material on sealing performance were obtained with prototypes comprising six gaskets. Stress analysis was possible with plate deformation measurements in a heat exchanger comprising twenty plates. Highest stress levels were obtained with EPDM gaskets during tightening. It is conjectured that higher operation loads can occur with the latter material. Empirical correlations relate sealing capacity and compression level for EPDM and HNBR gaskets.