Liquid redox sulfur recovery options, costs, and environmental considerations

Dalrymple, Dwyann; Trofe, T.W.; Evans, James G.

doi:10.1002/ep.3300080412

Cited by 17 publications

(13 citation statements)

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“…It was also observed that the presence of DOM affects the way sulfide is oxidized, with thiosulfate rather than elemental sulfur or polysulfide as the main reaction products (Heitmann and Blodau, 2006;Heitmann et al, 2007). Furthermore, some chemical sulfide oxidation processes in practice, so-called 'liquid redox processes', use catalysts (Dalrymple et al, 1989). For example, in the Stretfort process, sulfide is oxidized by oxidized transition metals that are regenerated by organic RM that eventually shuttle electrons to oxygen (Steudel, 1996).…”

Section: Sulfide Oxidationmentioning

confidence: 99%

Impact and application of electron shuttles on the redox (bio)transformation of contaminants: A review

Zee¹,

Cervantes²

2009

Biotechnology Advances

448

200

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During the last two decades, extensive research has explored the catalytic effects of different organic molecules with redox mediating properties on the anaerobic (bio)transformation of a wide variety of organic and inorganic compounds. The accumulated evidence points at a major role of electron shuttles in the redox conversion of several distinct contaminants, both by chemical and biological mechanisms. Many microorganisms are capable of reducing redox mediators linked to the anaerobic oxidation of organic and inorganic substrates. Electron shuttles can also be chemically reduced by electron donors commonly found in anaerobic environments (e.g. sulfide and ferrous iron). Reduced electron shuttles can transfer electrons to several distinct electron-withdrawing compounds, such as azo dyes, polyhalogenated compounds, nitroaromatics and oxidized metalloids, among others. Moreover, reduced molecules with redox properties can support the microbial reduction of electron acceptors, such as nitrate, arsenate and perchlorate. The aim of this review paper is to summarize the results of reductive (bio)transformation processes catalyzed by electron shuttles and to indicate which aspects should be further investigated to enhance the applicability of redox mediators on the (bio)transformation of contaminants.

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Section: Sulfide Oxidationmentioning

confidence: 99%

Impact and application of electron shuttles on the redox (bio)transformation of contaminants: A review

Zee¹,

Cervantes²

2009

Biotechnology Advances

448

200

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“…The test was terminated due to changing operating conditions at the plant. 8. An assessment of hydrogen sulfide-prone gas reserves in the United States showed that about 13% of the known natural gas reserve contains hydrogen sulfide.…”

Section: Discussionmentioning

confidence: 99%

“…Corrosion in the amine regeneration reboiler is an issue, and problems associated with foaming and amine losses from stripper overhead are frequently cited and discussed in the literature. 6 Low-volume, low-concentration sour gas streams [7][8][9][10][11] are best treated by specialized scavenging or Redox sulfur recovery processes, such as Stretford, LO-CAT, Sulfa-Scrub, Sulfa-Check, Chemsweet, Supertron 600, solid iron sponge or solid zinc oxide. However, many scavengers present substantial disposal problems, and in a number of states, the spent scavenger constitutes toxic waste.…”

Section: < 15fmentioning

confidence: 99%

Low-quality natural gas sulfur removal/recovery

Amo¹,

Baker²,

Helm³

et al. 1998

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A significant fraction of U.S. natural gas reserves are subquality due to the presence of acid gases and nitrogen; 13% of existing reserves (19 trillion cubic feed) may be contaminated with hydrogen sulfide. For natural gas to be useful as fuel and feedstock, this hydrogen sulfide has to be removed to the pipeline specification of 4 ppm. The technology used to achieve these specifications has been amine, or similar chemical or physical solvent, absorption. Although mature and widely used in the gas industry, absorption processes are capital and energy-intensive and require constant supervision for proper operation. This makes these processes unsuitable for treating gas at low throughput, in remote locations, or with a high concentration of acid gases. The U.S. Department of Energy, recognizes that exploitation of smaller, more sub-quality resources will be necessary to meet demand as the large gas fields in the U.S. are depleted. In response to this need, Membrane Technology and Research, Inc. (MTR) has developed membranes and a membrane process for removing hydrogen sulfide from natural gas. During this project, high-performance polymeric thinfilm composite membranes were brought from the research stage to field testing. The membranes have hydrogen sulfide/methane selectivities in the range 35 to 60, depending on the feed conditions, and have been scaled up to commercial-scale production. A large number of spiral-wound modules were manufactured, tested and optimized during this project, which culminated in a field test at a Shell facility in East Texas. The short field test showed that membrane module performance on an actual natural gas stream was close to that observed in the laboratory tests with cleaner streams. An extensive technical and economic analysis was performed to determine the best applications for the membrane process. Two areas were identified: the low-flow-rate, high-hydrogen-sulfide-content region and the high-flow-rate, high-hydrogen-sulfide-content region. In both regions the MTR membrane process will be combined with another process to provide the necessary hydrogen sulfide removal from the natural gas. In the first region the membrane process will be combined with the SulfaTreat fixed-bed absorption process, and in the second region the membrane process will be combined with a conventional absorption process. Economic analyses indicate that these hybrid processes provide 20-40% cost savings over stand-alone absorption technologies.

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“…Various binary oxides such as V-Mg, V-Bi, V-Mo, V-Sb, Fe-Sn and Bi-Mo were tested in excess oxygen without water [11,12]. Solid solutions of vanadium, A 4 AEyV 2 AExO 9 (A = Mg, Ca or Zn, 0 x 0:2; 0 y 0:5) [13,14] were also reported as active catalysts, even in the presence of 30 vol.% of water. The heterogeneous catalytic systems for the processes showed the high activity, but the high reaction temperature resulted in the low stability of the catalysts by the sulfidation of metal and metal oxide components as well as in the low selectivity by the formation of SO 2 .…”

Section: Introductionmentioning

confidence: 99%

“…These have some advantages over other processes in terms of simplicity and performace. The developed processes are using either a V 5þ /V 4þ couple (Stretford and Unisulf) or a Fe 3þ /Fe 2þ couple (Lo-Cat, Lo-Cat II, Sulferox, and Bio-SR) with chemicals for stabilizing the vanadium, or iron [13][14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Catalytic Wet Oxidation of H2S to Sulfur on V/MgO Catalyst

et al. 2004

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The V/MgO catalysts with different V 2 O 5 loadings were prepared by impregnating MgO with aqueous vanadyl sulfate solution. All of the catalysts were characterized by X-ray diffraction (XRD), temperature-programmed reduction (TPR), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). It was observed that the H 2 S removal capacity with respect to vanadia content increased up to 6 wt%, and then decreased with further increase in vanadia loading. The prepared catalysts had BET surface areas of 11:3 $ 95:9 m 2 /g and surface coverages of V 2 O 5 of 0:1 $ 2:97. The surface coverage calculation of V 2 O 5 suggested that a vanadia addition up to a monomolecular layer on MgO support increased the H 2 S removal capacity of V/MgO, but the further increase of VO x surface coverage rather decreased that. Raman spectroscopy showed that the small domains of Mg 3 (VO 4 ) 2 could be present on V/MgO with less than 6 wt% vanadia loading. The crystallites of bulk Mg 3 (VO 4 ) 2 and Mg 2 (V 2 O 7 ) became evident on V/MgO catalysts with vanadia loading above 15 wt%, which were confirmed by a XRD. The TPR experiments showed that V/MgO catalysts with the loading below 6 wt% V 2 O 5 were more reducible than those above 15 wt% V 2 O 5 . It indicated that tetrahedrally coordinated V 5þ in well-dispersed Mg 3 (VO 4 ) 2 domains could be the active species in the H 2 S wet oxidation. The XPS studies indicated that the H 2 S oxidation with V/MgO could proceed from the redox mechanism (V 5þ M V 4þ ) and that V 3þ formation, deep reduction, was responsible for the deactivation of V/MgO.

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Liquid redox sulfur recovery options, costs, and environmental considerations

Cited by 17 publications

References 1 publication

Impact and application of electron shuttles on the redox (bio)transformation of contaminants: A review

Impact and application of electron shuttles on the redox (bio)transformation of contaminants: A review

Low-quality natural gas sulfur removal/recovery

Catalytic Wet Oxidation of H2S to Sulfur on V/MgO Catalyst

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