Measurements of diffusivity of chlorinated VOCs in heavy absorption solvents using a laminar falling film contactor

The diffusivity of VOC in absorption solvents has been determined in view to modelling the performance of G/L processes for treatment of VOC-containing gases. The laminar falling film technique was used for the examples of dichloromethane (DCM) and tetrachloroethylene (TCE), to be absorbed in 2-di-ethylhexyl adipate (DEHA). The technique led to accurate results for DCM. In contrast, the moderate volatility of TCE corresponds to a low Henryʹs law constant; the absorption was then largely controlled by gas-side transfer, the rate of which had to be accounted for in treatment of the absorption data. Nevertheless, as discussed in the paper, the well-known technique is poorly applicable in case of too soluble gases, i.e. exhibiting Henryʹs constants below 1 Pa m3 mol−1.