Elemental mercury adsorption on sulfur-impregnated porous carbon - a review

The presence of elemental mercury in wellhead natural gas is an important industrial problem, since even low levels of mercury can damage cryogenic aluminium heat exchangers and other plant equipment. Mercury present in the natural gas stream will also dramatically shorten the useful life of precious metal catalysts. The present work reviews the overall process of elemental mercury removal in practice using non-regenerative adsorbents (e.g. sulfur-impregnated porous carbon), addressing the various influencing parameters such as the method of sulfur impregnation, the impregnation temperature, the sulfur to carbon ratio, the impregnation time, the impact of flue gas constituents, the effect of processing temperature, and the nature of any carbon-containing functional groups present. The distribution of elemental sulfur is found to be the key to developing an effective adsorbent, rather than quantity of sulfur impregnated. Modifying or developing an adsorbent for elemental mercury removal from natural gas needs a detail physical and chemical characteristics assessment of the adsorbent.