Adsorption of H2S from Natural Gas using treated Oil Fly Ash

Abstract

Oil fly ash (OFA) is treated by different mixtures of oxidizing agents; followed by either steam or CO2 activation. A setup is designed where steam generated at 8bar and 300°C is injected through a long coil tubing which is kept with the OFA sample in an oven. The oven temperature is maintained at three different temperatures namely 330, 660, and 990°C. The activated samples were characterized for their surface area, pore size distribution and morphology. The treatment with 40wt.% (16M) HNO3, 40wt.% (18M) H3PO4 and 20wt.% (18M) H2SO4 followed by CO2 activation at 990°C has shown the highest surface area of 375m2/g. SEM images have shown more micro-pores and well developed particle size and porous structure resulting from steam activation at high temperature. Acid activation provided -OH- functional group, which is also confirmed by FTIR analysis. The maximum adsorption capacity for H2S from natural gas, obtained at ambient conditions and a flow rate of 0.4L/min, is found to be 4.9mg/g. The sorption kinetics has shown chemisorption of H2S on the surface. The sorption isotherm shows a multilayer adsorption, which fits BET equation.