Numerical Modeling of Industrial Scale Transport Membrane Condenser Based Heat Exchangers for Flue Gas Waste Heat and Water Recovery

In this paper, the effects of different working conditions on the performance of Transport Membrane Condenser (TMC) based heat exchangers are studied numerically. The effects of non-condensable gases on the condensation rate along with the number and distances of the TMC tubes in longitudinal and transversal directions were investigated. The numerical simulations have been conducted using the commercial software Ansys Fluent 14.5 and the condensation and heat and mass transfer are implemented using User Defined Functions (UDFs) in the numerical setup. The RNG two-equation turbulence model is used to handle heat, mass and momentum transfer across the TMC bundle tubes. The results are depicted in terms of volume fraction of water vapor and averaged outlet temperature of cooling water and flue gas. The results revealed that increase of the number of TMC tubes, when the inlet flow rate is constant, increases both the condensing surface area and average surface temperature which have opposite effects on the condensation rate, hence both of these parameters should be considered in industrial applications.