Minimum mass-entransy dissipation profile for one-way isothermal diffusive mass-transfer process with mass-resistance and mass-leakage

As a new concept, mass-entransy is one of the twins in the core of entransy theory. It can describe mass-transfer ability for mass-transfer processes (MTPes), just as thermal-entransy for describing heat-transfer ability. Accordingly, mass-entransy dissipation can be utilized to evaluate the loss of mass-transfer ability. Minimum mass-entransy dissipation (MMED) is utilized to optimize one-way isothermal diffusive MTPes with mass-leakage and mass-transfer law (g proportional to Delta(c), where c means concentration). For a given net amount of mass-transferred key components at the low-concentration side, optimality-condition for the MMED of isothermal diffusive MTPes is obtained by using the averaged-optimization-method. Effects of the amount of mass-transferred and mass-leakage on optimal results are analyzed, and the obtained optimization profiles are compared with those for MTP profiles of constant-concentration-difference (c1 - c2 = const) and constant-concentration-ratio (c1 / c2 = const). The product of square of key-component-concentration (KCC) difference between high- and low-concentration sides and inert component concentration at high-concentration side for the MMED of the MTP with no mass-leakage is a constant, and the optimal relationship of the KCCs between high- and low-concentration sides with mass-leakage is significantly different from the former. When mass-leakage is relatively small, the MTP with c1 - c2 = const strategy is superior to that with c1 / c2 = const strategy, and the latter is superior to the former with an increase in mass-leakage. A combination of mass-entransy concept, finite-time thermodynamics, and averaged-optimization-method is a meaningful tool for optimizing MTPes.