M.R. Othman

Present technologies for hydrogen sulfide removal from gaseous mixtures

Abstract Natural gas, refinery gas, and coal gas contain acid gases such as hydrogen sulfide (H2S) and carbon dioxide that must be removed from the gas stream due to the toxicity of H2S and to prevent corrosion to piping and production facility caused by the acid gases. In this article, current technologies for the acid gas removal are selected and reviewed. The review includes absorption, adsorption, conversion of H2S into elemental sulfur, and membrane reactor for H2S decomposition and desulfurization. Recently, hollow fiber membrane contactor has been in the limelight of research in H2S absorption from gaseous mixture due to its potential to overcome problems such as foaming and loading. Recent trends on Claus tail gas cleanup technologies are highlighted due to the recent progress in membrane technology. The article also suggests current research on the acid gas removal technology using catalytic membrane reactor. The interest on finding suitable active component and support and studying the membrane structure for enhanced removal of acid gases is likely to be rekindled in the near future.

Thermodynamic Functions of Temperature/Pressure-induced Sorption across Microporous Membranes: Case Study of Methane and Carbon Dioxide

This paper introduces a facile technique for the calculation of the thermodynamic properties of a gas across a porous membrane. The calculation assumes that the gas undergoes temperature-driven isobaric condensation, pressure-driven isothermal expansion and temperature-driven isobaric evaporation. The gas is in a disordered and chaotic state in all the three processes as a result of the kinetic energy by the driving forces. A zero entropy value is achievable at a remote distance from the membrane after desorption takes place. The deviation of the entropy from zero for isobaric evaporation is indicative of the irreversibility of the process. In contrast, the convergence of the entropy towards zero for the other two systems is indicative of the near-reversibility of the process.

Pressure Swing Adsorption Technologies for Carbon Dioxide Capture

The principles of pressure swing adsorption (PSA) for carbon dioxide capture are reviewed. Previous work on PSA, relevant modeling and experimental investigation for specifically carbon dioxide separation are also presented and significant findings highlighted. Simple rules for PSA process design based on analysis of the inherent properties of adsorbate-adsorbent systems encompassing equilibrium isotherm, adsorption kinetics, shape of breakthrough curves, screening and selection of adsorbent, bed porosity, adsorption time, purge to feed ratio, residence time, pressure equalization and rinse steps are provided to promote better understanding of the technology so that it gains wider acceptance in the future to address the global environmental concern, particularly in the removal of carbon dioxide as a greenhouse gas.

Identification of Molecular Transport Mechanisms in Micro-Porous Hydrotalcite–Silica Membrane

Hydrotalcite (HT) materials have been known to be able to adsorb

Fractal Rate of Adsorption and Surface Diffusivity of Carbon Dioxide across Mesoporous Adsorbents

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Characterization of macro-scale heterogeneity and homogeneity of porous media employing fractal geometry

CO2 even at high temperature. However, HT has not been made into a micro-porous membrane because of its meso-porous nature. In order to form a micro-porous HT membrane, silica was selected as a host matrix due to its ability to retain its micro-porosity. In this paper, a micro-porous hydrotalcite–silica membrane was formed on a meso-porous

The Effect of Hydrotalcite Content in Microporous Composite Membrane on Gas Permeability and Permselectivity

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