Sulphur cycling

Capaldo, K., Corbett, J. Kasibhatla, P., Fischbeck, P., and Pandis, S. N. (1999). Effects of ship emissions on sulphur cycling and radiative climate forcing over the ocean. Nature, 400, 743-746. 

Freney, J. R., Ivanov, M. V., and Rodhe, H. (1983). The sulphur cycle. In The Major Biogeochemical Cycles and Their Interactions, SCOPE 21" (B. Bolin and R. B. Cook, eds). WUey, Chichester. 

Granat, L., Rodhe, H., and Hallberg, R. O. (1976). The global sulphur cycle. In Nitrogen, Phosphorus and Sulphur - Global Cycles" (B. H. Svensson and R. Soderlund, eds) pp. 89-134. SCOPE Report 7, Ecol. Bull., Stockholm. 

Ivanov, M. V. (1983). Major fluxes of the global biogeochemical cycle of sulphur. In The Global Biogeochemical Sulphur Cycle, SCOPE 19 (M. V. Ivanov and J. R. Freney, eds). Wiley, Chichester. 

Jorgensen BB. 1982. Ecology of the bacteria of the sulphur cycle with special reference to anoxic-oxic interface environments. Philos Trans R Soc Lond B Biol Sci 298 543-561. 

Carlson et al. (1999b) compared laboratory spectra and Galileo data and suggested that hydrated sulphuric acid is the main component in the dark surface material, which probably also contains sulphur polymers modified by radiation chemistry. A sulphur cycle involving three sulphur species is suggested sulphuric acid (H2SO4), sulphur dioxide (SO2) and sulphur polymers (S ). 

Canfield, D.E., Habicht, K.S. and Thamdrup, B. (2000). The Archean sulphur cycle and the early history of atmospheric oxygen. Science, 288, 658-661... 

Goldstein, S. et al., Upper bound and best estimate of the efficiency of the iodine sulphur cycle, Int.. Hydrogen Energ., 30, 619, 2005. 

Zhuang, G., Z. Yi, R. A. Duce, and P. R. Brown, Link between Iron and Sulphur Cycles Suggested by Detection of Fe(II) in Remote Marine Aerosols, Nature, 355, 537-539 (1992). 

O Dowd, C. D., M. H. Smith, I. E. Consterdine, and J. A. Lowe, Marine Aerosol, Sea-Salt, and the Marine Sulphur Cycle A Short Review, Atmos. Environ., 31, 73-80 (1997b). 

It illustrates the different stages in the manufacture of soda by the Leblanc process. The sulphur cycle in that process is also illustrated diagrammatically by the scheme ... 

Howarth R.W. Stewart J.W.B. and Ivanov M.V. (eds.). (1992). Sulphur Cycling on the Continents Wetlands, Terrestrial Ecosystems, and Associated Water Bodies. Wiley, Chichester, U.K., 372 pp. 

Over the past few years we have been studying the waters around the United Kingdom, including the North Sea, Irish Sea and N.E. Atlantic, in order to characterise dimethyl sulphide (DMS) emissions and assess the significance of this natural contribution to acidity of rainfall and the sulphur cycle. Biogenic DMS concentrations in seawater vary considerably both temporally and spatially and coastal and shelf water systems often contain higher concentrations of volatile sulphur than the open oceans (1.2). 

For the hybrid sulphur cycle, current researches are focused on the SDE cell development to overcome the sulphur deposition in cathode. The next step should be ILS experiments followed by a MW-scale pilot plant. 

Session 4 focused on recent advances in the thermochemical copper chloride and calcium bromide cycles. Much of the current research on thermochemical cycles for hydrogen production involves the sulphur cycles (sulphur-iodine, hybrid sulphur), however, these cycles require very high temperatures ( 800-900°C) to drive the acid decomposition step. The interest in the Cu-Cl and Ca-Br cycles is due to the lower peak temperature requirements of these cycles. The peak temperature requirement for the Cu-Cl cycle is about 550°C, which would allow this cycle to be used with lower temperature reactors, such as sodium- or lead-cooled reactors, or possibly supercritical water reactors. Ca-Br requires peak temperatures of about 760°C. Both of these cycles are projected to have good efficiencies, in the range of 40%. Work on Cu-Cl is ongoing in France, Canada and the United States. Work on Ca-Br has been done primarily in Japan and the US, with the more recent work being done in the US at ANL. The papers presented in this session summarised the recent advances in these cycles. 

The sulphuric acid decomposition reaction to regenerate S02 and to produce oxygen, (2), is common to all sulphur cycles, including the sulphur-iodine (S-I) cycle. What distinguishes the HyS process from the other sulphur cycles is the use of sulphur dioxide to depolarise the anode of a water electrolyser, as shown in reaction (1). 

Goldstein, S., J.M. Borgard, X. Vitart (2005), Upper Bound and Best Estimate of the Efficiency of the Iodine Sulphur Cycle , Int.J. Hydrogen Energy, 30, 619-626. 

Evaluation studies (Shin, 2007) on the efficiency of the SI thermochemical cycle, the high temperature steam electrolysis, and the hybrid sulphur cycle is ongoing based on the recent achievements over the world (Shin, 2008). 

INTEGRATED LABORATORY SCALE DEMONSTRATION EXPERIMENT OF THE HYBRID SULPHUR CYCLE AND PRELIMINARY SCALE-UP... 

Integrated laboratory scale demonstration experiment of the hybrid sulphur cycle and preliminary scale-up... 

CEA has chosen to focus on a limited number of potentially interesting processes, namely the high temperature electrolysis, the iodine/sulphur cycle and the hybrid sulphur cycle (Figure 1). Other options are evaluated on a more limited basis. Rather than building expensive large scale demonstration loops, emphasis is placed on experiments their goals are to better understand the thermodynamic behaviour of the chemical system to implement more reliable models. 

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