Thermochemical water-splitting cycles

Non-electrolytic sources of hydrogen have also been studied. The chemical problem is how to transfer the correct amount of free energy to a water molecule in order to decompose it. In the last few years about I0(X)0 such thermochemical water-splitting cycles have been identified, most of them with the help of computers, though it is significant that the most promising ones were discovered first by the intuition of chemists. 

Norman, J.H. et al., Thermochemical water-splitting cycle, bench-scale investigations and process engineering, GA-A 16713,1982. 

Kubo, S. et al., Corrosion test on structural materials for iodine-sulfur thermochemical water splitting cycle, in Proc. 2nd Topical Conf. on Fuel Cell Tech., AIChE 2003 Spring National Meeting, New Orleans, March 30-April 3, 2003. 

The sulfur-iodine thermochemical water-splitting cycle (S-1 cycle) developed for hydrogen production from water is fundamentally based on the following three chemical reactions (Wang, 2007) ... 

Norman JH, Mysels KJ, Sharp R, Williamson D (1982) Studies of the sulfur-iodine thermochemical water-splitting cycle. Int J Hydrogen Energy 7 545-556... 

O Keefe, D.R., et al. (1982), Preliminary Results from Bench-scale Testing of Sulphur-iodine Thermochemical Water-splitting Cycle , Int. J. Hydrogen Energy, 7 (5), 381-92. 

Norman, J.H., et al. (1982), Thermochemical Water-splitting Cycle, Bench-scale Investigations and Process Engineering. Final Report for the Period February 1977 through December 31, 1981, GA-A16713 report, May. 

These studies also indicate an overall efficiency (ratio of higher heating value of hydrogen output to the nuclear heat input) in the range of 40 to 43%, which is comparable to that presently estimated for the most promising thermochemical water splitting cycles. 

Norman, J. H. Mysels, K. J. O Keefe, D. R. Stowell, S. A. Williamson, D. G., "Chemical Studies on the General Atomic Sulfur-Iodine Thermochemical Water-Splitting Cycle," paper presented at the Second World Hydrogen Energy Conference, Zurich, Switzerland, August 1978. 

Kubo, S. et al.. Corrosion Test on Strnctnral Materials for Iodine-Sulfur Thermochemical Water-Splitting Cycle, paper presented at the Proceedings of the 2nd Topical Conference on Fuel Cell Technology, AlChE 2003 Spring National Meeting, 2003. 

Ginosar, D.M., Glenn, A.W., and Petkovic, L.M., Stability of Sulfuric Acid Decomposition Catalysts for Thermochemical Water Splitting Cycles, paper presented at the AlChE Spring Meeting 2005, Atlanta, 2005. 

A NEW SOLAR METAL SULFATE - AMMONIA BASED THERMOCHEMICAL WATER SPLITTING CYCLE FOR THE PRODUCTION OF HYDROGEN... 

Hydrogen production via thermochemical water splitting cycles (TCWSCs)... 

Decomposition of sulfuric acid presents an efficient means of generating oxygen via a solar thermochemical water splitting cycle pending the required reaction temperatures can be realizable. 

Where qs (WW) refers to the solar flux intercepted by unit area of the receiver at the focal plane and I (WW) is the incident normal beam insolation. Cr is often expressed in units of suns when normalized to 1 = 1000 W/m [13]. The solar flux concentration ratio typically obtained is at the level of 100, 1000, and 10,000 suns for trough, tower, and dish systems, respectively. The most suitable concentrators for applications involving solar thermochemical water splitting cycles are tower and dish systems. 

Figure 6. Schematic diagram of S-NH3 photo-thermochemical water splitting cycle.

Brown, E C., G.E. Besenbruch, K.R. Schultz, A C. Marshall, S.K. Showalter, P.S. Pickard, J.F. Funk (2002), Nuclear Production of Hydrogen Using Thermochemical Water-Splitting Cycles. presented at International Congress on Advanced Nuclear Power Plants (ICAPP), Embedded Topical Meeting, Hollywood, Florida (June 9-13). 

J.H. Norman et al., Thermochemical Water-Splitting Cycle, Bench-Scale Investigations, and Process Engineering , General Atomic Report, GA-A 16713 (1982). 

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