Membrane Compatibility and its Characterization to Determine the Potential Applicability for H2S Separation

Abstract

Development of new technology in the area of separation process is essential in order to deal with with product quality, environmental issues, energy efficiency, cost reduction and increasing safety. In membrane separation processes, membrane contactor has attained considerable attention due to the wide range of its applications. Since most of chemical separation processes are related to the contact of two different phases (liquid-liquid or gas/vapor-liquid), the operations such as gas absorption and stripping, liquid-liquid extraction, distillation, heterogeneous reactions, emulsification, demulsification, humidification and dehumidification can be conducted through a membrane contactor system (Drioli et al. 2005). Development of membrane contactor for acid gas removal is an emerging technology recently especially to overcme the disadvantages of commercial packed towers and bubble columns. Physical solvents such as DEPG (Selexol™ or Coastal AGR®), NMP or N-Methyl-2-Pyrrolidone (Purisol®), Methanol (Rectisol®), and Propylene Carbonate (Fluor Solvent™) are well known as commercial gas treating solvents, especially for acid gas removal. Physical solvents tend to be favored over chemical solvents when the concentration of acid gases or other impurities is very high (Burr and Lyddon 2008). Among the physical solvents, Selexol shows the highest H2S solubility. However, due to Selexol solvent is less hazard as compared to NMP, this compatibility study was conducted using Selexol as the solvent for H2S removal with various types of polymeric membrane material. The main objective of the study was to test the stability of potential porous membrane material with the selected physical absorbent for H2S removal. From the physical characterization consist of physical abservation, Fe-SEM, FTIR and contact angle that have been conducted on the membranes that have been immersed in the physical absorbent for 1 month, it is found that 3 membrane materials are most stable and compatible with the selected physical absorbent. The 3 shortlisted membrane material are PTFE, PP and PEEK membrane that could be further developed for H2S removal using membrane contactor technology.