Oxidation of low concentrations of hydrogen sulfide over activated carbon

Abstract

The oxidation of low concentrations of hydrogen sulfide with air over activated carbon was studied over the temperature range 24‐200°C using both fixed and fluid bed reactors. The predominant reaction, H2S + ½ Oa → H2O + S, was found to have an order of 0.5 with respect of H2S concentration. Activity of the catalyst decreased as the amount of sulfur deposited on it increased. Indirect evidence suggests that adsorption of water by the carbon also decreases its activity as a catalyst at lower temperatures. Values of the activation energy and the frequency factor were determined for various sulfur loadings using the fixed bed reaction system. Regeneration of the carbon loaded with sulfur was studied at temperatures between 150 and 500°C using steam as a carrier gas. Bright yellow sulfur was recovered. The regenerated carbon was shown to have its original activity.

Direct oxidation of hydrogen sulphide to sulphur using impregnated activated carbon catalysts

“…Coskun and Tollefson (1980) and Ghosh and Tollefson (1986a) found similar results. The rate of SO 2 production increased substantially above 175…”

“…Studies by several researchers (Carioso and Walker, 1975;Coskun and Tollefson, 1980;Kaliva and Smith, 1983) concluded that microporous activated carbons were catalytically active for the oxidation of H 2 S to sulphur (Carioso and Walker, 1975;Wu et al, 2005). However, Bandosz (1999) observed that heterogeneous carbon having both micropores and mesopores perform better than predominantly microporous mate-rial with high surface area.…”

On the Adsorption/Oxidation of Hydrogen Sulfide on Activated Carbons at Ambient Temperatures

“…It is intuitively expected that pore volume should be a limiting factor for the H 2 S immobilization. After adsorption the products of catalytic oxidation, either sulfur or sulfuric acid (16,17,(24)(25)(26)(27), have to be stored in the carbon pore system. In the ideal situation no more hydrogen sulfide can be adsorbed and converted into sulfur than the available pore volume in the adsorbent permits.…”

“…To obtain meaningful results the experiments should be done at very low concentrations of H 2 S, taking into account the possibility of large differences in the rates of the two processes. Oxidation of H 2 S on caustic carbon is a fast reaction (2,4), while oxidation on unmodified carbon is rate-limited due to the complexity of the process (7,10,26,27,28). When the concentration is low and the contact times in the bed are long enough both processes can go to completion.…”

Applications of organic phase change materials embedded in adsorbents for controlling heat produced by charging and discharging natural gas

“…The adsorbed natural gas (ANG) technique, which stores natural gas by adsorption in microporous carbonaceous adsorbents at medium pressure and room temperature, is being considered as an on-board storage technology for natural gas vehicles because of its low capital and operation costs in comparison to compressed natural gas (CNG) storage (Matranga et al 1992). Much progress has been made in ANG technology in improving the quality of adsorbents to achieve the goal of commercial application for natural gas vehicles (Marsh and Yan 1984;Cal et al 2000;Coskun and Tollefson 1980;Li et al 2003;Li and Chen 2011). However, adsorption heat generation during charging and discharging natural gas significantly affects adsorptive efficiency.…”