(68a) Key Note: Heat Exchanger Design on Paper Vs Practice

Shell-and-Tube heat exchangers in the Oil & Gas business are designed using Standards which cover mechanical, thermal, and fabrication aspects. Multiple Standards are used; Industry Standards such as API, ISO, TEMA and internal Standards of the EPC and end-user companies. The Standards are based on many years of combined experience of the several companies involved in the design, fabrication, and operation of the heat exchangers. The purpose of the Standards is to ensure a minimum quality in the design, especially when the design may be done by a party without access to operational experience. In the field, heat exchangers often operate at flow, temperature, pressure, and fluid composition conditions substantially different than assumed in the design. The purpose of this presentation is to briefly discuss the philosophy behind Standards and to highlight situations where Standards do not take into account operational variations. These variations from design assumptions lead to unexpected failures of heat exchangers. The presentation will emphasize the point of view that although all Standards are based on sound principles, the designer must consider operational issues and deviate from the Standards as much as necessary to create a reliable design for real life.