Removal of hydrogen sulfide from natural gas through an electrochemical membrane separator

Abstract

An advanced process is developed for the separation of H2S from natural gas through an electrochemical membrane. H2S is removed from naturalgas by reduction to the sulfide ion and H2 at the cathode. The sulfide ion migrates to the anode through a molten salt electrolyte suspended in an inert ceramic matrix. Once at the anode it is oxidized to elemental sulfur and swept away for condensation in an inert gas stream. The natural gas is enriched with H2. Order-of-magnitude reductions in H2S concentration have been repeatedly recorded on a single pass through the cell. This process allows removal o f H2S, whileproducing H2 and elementalsulfur directly. No absorbents are used, and there is no need for subsequent treatment of a concentrated H2S stream as with conventional gas sweetening technology. This makes the process economically attractive, since it is much less equipment-intensive than conventional technology.

HIGH TEMPERATURE REMOVAL OF H{sub 2}S FROM COAL GASIFICATION PROCESS STREAMS USING AN ELECTROCHEMICAL MEMBRANE SYSTEM

“…The thermodynamic data in Figure 28 imply that higher H 2 S removal rates are possible at higher temperatures because more sulfide is favored in the electrolyte via Reaction (6). This enables higher current efficiency for sulfur removal because the concentration gradient across the membrane in Equation (5) …”

“…4 NiO was shown to be a viable cathode material for polishing applications (i.e. H 2 S levels below 60 ppm) 5,6,7 , and optimum cell performance was modeled at low, intermediate, and…”

Membrane reactors for the desulfurization of power plant gas emissions and transportation fuels

“…Alexander and Winnick (1994) In addition, a mediator can be applied to increase the removal of sulfur in the indirect electrochemical desulfurization processes, in which the mediator can be regenerated at the electrode. SO 2 may be produced in the process of oxidation.…”

Palladium-based membranes for hydrogen separation: preparation, economic analysis and coupling with a water gas shift reactor

“…The main potential applications of membrane reactors in the petrochemical industry or for environmental protection are: methane steam reforming (Basile et al ., 2003 ;Chen et al ., 2008 ;Jorgensen et al ., 1995 ;Kikuchi et al ., 2000 ;Lin et al ., 2003 ;Patil et al ., 2007 ;Shu et al ., 1995 ;Tong and Matsumura, 2005 ;Uemiya et al ., 1991 ), oxidative coupling of methane (Guo et al ., 1997 ;Langguth et al ., 1997 ;Nozaki and Fujimoto, 1994 ;Ramachandra et al ., 1996 ;ten Elshof et al ., 1995 ;Tonkovich et al ., 1996 ;Xu and Thomson, 1997 ;Zheng et al ., 1998 ;Zheng and Lin, 2000 ), WGS (Barbieri et al ., 2005(Barbieri et al ., , 2008Basile et al ., 1996 ;Brunetti et al ., 2007aBrunetti et al ., , 2007bCriscuoli et al ., 2000 ;Galuszka et al, 2011 ;Mendes et al ., 2010 ), methanol steam reforming (Itoh et al ., 2002 ), methane dry reforming (Ferreira-Aparicio et al ., 2002 ) and SO 2 and H 2 S removal (Alexander and Winnick, 1994 ).…”