Regenerative oil scrubbing of volatile organic compounds from a gas stream in hollow fiber membrane devices

A regenerative membrane-based absorption process has been extensively studied to remove volatile organic compounds (VOCs) from air/N₂ using silicone oil as the absorbent. The absorbent liquid is regenerated by applying a vacuum in a membrane-based stripper. In this process, there are no flooding, loading, and entrainment, which limit the gas/liquid flow rate in the traditional absorption process. In the present study, attention has been focused on the removal of volatile component(s) from binary gas mixtures such as methanol-N₂ and toluene-N₂ and from a model multicomponent mixture of gasoline vapor constituents and nitrogen. The process performance was tested under three conditions: (i) absorption with fresh absorbent; (ii) absorption and stripping modules at the same (room) temperature; (iii) maintaining different temperatures in the absorption and stripping modules. Henry's law constants and diffusivities of VOCs in silicone oil needed to simulate the process performances have been experimentally measured at different temperatures. The experimental results have been compared with theoretical predictions.