Heat Exchanger Design: Why Guess a Design Fouling Factor when It Can Be Optimized

摘要

A new general surface heat exchanger design relationship is derived that uniquely relates the optimum design fouling resistance and the optimum design heat transfer coefficient with the ratio of cleaning cost to capital plus operating costs, at the optimum design condition. Implementation of this simple result to practical problems in design, however, requires numerical techniques. A new shell and tube heat exchanger design program, SIZEHX, is applied to a problem of current interest to confirm the derivation. SIZEHX can cost effectively perform single-step, multiparameter cost optimizations on single phase or supercritical exchanger arrays with variable fluid properties and arbitrary linear fouling for single-pass, segmentally baffled shell-and-tube configurations for a variety of fluid pairs, including hydrocarbon mixtures. The economic influence of several general design parameters on a geothermal exchanger are presented in the form of 3-D computer generated plots. (ERA citation 04:026142)