Analysis of Absorption with Complex Reversible Reaction
Jerry H. Meldon, Tufts University, Chemical and Biological Engineering Department, Medford, MA 02155
Design of packed scrubbers requires accurate solution to local differential mass balances. The daunting mathematical challenges when there are multiple reversible reactions with nonlinear kinetic expressions are typically addressed using computationally intensive numerical methods. However, as shown here, the kinetic terms in the ordinary differential equations associated with Film Theory may be linearized by either of two different techniques with negligible loss of accuracy. One approach, developed by Van Krevelen and Hoftijzer to analyze absorption with a single irreversible reaction, fixes the concentration of a nonvolatile reactant at its (unknown) value at the gas-liquid interface. The other approach, originally developed by K. A. Smith to analyze permeation with reversible reaction, assumes that departures from local reaction equilibrium are small. Previously, we demonstrated that either approach yields near-exact values for the “Enhancement Factor” by which a single reaction multiplies the local absorption rate. We present results here that demonstrate similar accuracy when either linearization technique is applied to the analysis of absorption and multiple reversible reactions.