Recovery of Sulfur Dioxide Using Non-Dispersive Absorption

Abstract

Removal of SO2 from gas emissions by selective absorption into a liquid is a common method to reduce air pollution and environmental risks. The absorption efficiency is determined by the interaction between the gases and the liquid. A great number of gas desulphurization methods have been developed where aqueous or organic solvents are used as sorbents.N,N-dimethylaniline (DMA) is an organic solvent used in the industry because its affinity with SO2. This absorption is neither too strong nor too weak, thus absorption and desorption can occur leading to a regenerative process where SO2 can be recovered. However, a direct contact between SO2 and DMA leads to several environmental problems caused by solvent evaporation and drops dragging into the gas stream.In order to increase the process efficiency and reduce environmental risks, a non-dispersive absorption process using hollow fibre membrane modules is developed in this work for a solvent zero emission process. The mass transfer into a fibre may be described by three main assumptions: gas-phase laminar flow, gas-phase plug-flow and gas-phase mixing. A numerical calculation was carried out to establish the performance of a hollow fibre membrane contactor for the removal of SO2 when water and N,N-dimethylaniline are used as sorbents in order to compare both, wetted and non-wetted operating modes.