Possibilities of improving the efficiency of power generation with regard to electrolytic water splitting

The efficiency of power generation has a considerable influence on the upper limit of the total efficiency of electrolytic water splitting. This paper deals with the energetic potential of power generation processes and therefore with the water electrolysis processes. In the investigations reported here, it was assumed that the heat source is always the same (high-temperature nuclear reactor). For comparing thermochemical or hybrid water splitting cycles and water electrolysis, the upper limit of process temperatures must be comparable, too. Therefore high-temperature processes for power generation have been investigated. A detailed energy and exergy balance is presented for the following cycles: (1) steam turbine cycles; (2) helium gas turbine cycles; (3) combined gas/steam turbine cycles. For these different processes an exergy analysis was performed in order to localize the process units, which make a considerable contribution to the decrease in total efficiency.     

Thermochemical processes for water splitting — Status and outlook

In this paper we discuss the proposals for processes which have already been realised in form of bench scale units or which have been planned, as well as those which have a high degree of development potential. A part of these cycles have in common the splitting of sulfuric acids which causes corrosion problems unsolved up to now. The essential part of the metal/metal hydride-processes is a hydrogen permeable membrane which separates the hydrogen acceptor from the water containing electrolyte melt. Actually we are intending to build up a lab cycle using a TiNi-basis membrane. The metal membranes offer a number of further interesting applications, such as (1) hydrogen production from gas mixtures at high temperatures, and (2) tritium separation from the helium of the HTR primary cooling circuit. A further promising process is the hydrocarbon hybrid cycle, in which the reduction of methanol to methane and oxygen is the key reaction. Till now we can detect a methane yield of up to 50%. An interesting combined procedure for the production of hydrogen and electricity is proposed, where sulphuric acid is decomposed by means of coal. The detailed mass and energy balance shows an efficiency of up to 57%. Thermodynamic analysis for the watersplitting cycles indicates efficiencies of up to 50%. Further research and development work is necessary in order to solve material problems and to demonstrate the suitability and availablity of the techniques using larger scale laboratory and prototype units.     

Thermochemical production of hydrogen by a vanadium/chlorine cycle. Part 2: Experimental investigation of the individual reactions

Chemical engineering aspects and the chemical practicability of a vanadium/chlorine hydrogen-producing cycle were investigated on a laboratory scale. The most significant results are presented and discussed. The total process was balanced and optimized using the experimental results as the basis. The overall thermal efficiency was calculated to be 42.5% (see Part 1).     

Autoradiographic investigation into the influence of factor XIII on wound healing in the animal experiment (author's transl)

1. In Wistar rats pretreated with factor XIII, placebo (human albumin solution), or physiological saline, a muscle wound was produced. For pre- and postlabelling purposes the animals received 3H-thymidine. 2. Autoradiographic and histological examinations revealed wound healing promoting activity of factor XIII from 72 h post operationem onwards. 3. 7 days after surgery, in contrast to the controls, the animals pretreated with factor XIII displayed sturdy, directed connective tissue in the wound bed with ample vascularization. 4. The method with pre- and postlabelling with 3H-thymidine elucidates that wound healing through factor XIII prevailingly occurs by faster fibroblast formation.