Status report on thermochemical iron/chlorine cycles: a chemical engineering analysis of one process

An iron/chlorine process with detailed flowsheeting is discussed. Mass and energy balances had been done to gain high efficiency. Results of 28–35% are achieved by an optimization of the HCl boiler system and by the high temperature heat balance requiring two paths for FeCl₂ hydrolysis. The dechlorination operates in two steps by means of a subcycle with carbon compounds. 35% efficiency is too low to guarantee economic feasibility but the development steps learned in this cycle should be valuable to other cycle studies.     

Exergoökonomische Bewertung einer Luftzerlegungs-Anlage

Exergoeconomic evaluation of an air-fractionation plant . This article presents a method for minimization of capital investment and energy costs for process plants. To this end the operating parameters are divided into two groups, i. e. into those affecting only the operation of individual components or groups of components and those of importance for operation of the entire plant. Optimization can therefore be undertaken in two steps: (1) optimization of plant components or group of components with regard to the operating parameters of the first group, (2) optimization of the entire plant with regard to operating parameters of the second group. This approach is illustrated by investment cost/exergy loss diagrams.     

Entropy production, efficiency, and economics in the thermochemical generation of synthetic fuels: II. The methanol water splitting cycle

The availability/heat penalty analysis described in our earlier paper [1] has been applied to the methanol-sulfuric acid water splitting cycle proposed by Schulten and Behr [2]. This four-reaction thermochemical process has been evaluated in terms of preliminary engineering design and economics by the Electric Power Research Institute (EPRI), the University of Kentucky and the CE-Lummus Co. [3]. The distribution of heat penalties induced by thermodynamic irreversibilities in the plant is shown, and the quantitative relationship among capital costs, production costs, heat penalties, and process efficiency is presented. The total thermal energy output of the nuclear reactor is the sum of the theoretical heat requirement and all the heat penalties in the plant. The costs, heat penalties and efficiency are also shown for the hybrid sulfuric acid process.     

Experimental and theoretical investigation of thermochemical hydrogen production

Hydrolysis, chlorination and the reverse Deacon reaction as steps of thermochemical water splitting cycles have been investigated in a laboratory scale with respect to feasibility and chemical engineering aspects. The results are discussed. Some general theoretical considerations concerning the efficiency of thermochemical water splitting cycles are presented. Using general criteria, some chemical reactions of proposed schemes of water splitting processes are selected and compared.     

Gear finishing by abrasive processes

Based on the position of hard finishing in the process chain of gear manufacturing, the dominant processes with a geometrically non-defined cutting edge are analysed. While processes like continuous profile grinding and discontinuous generating grinding with double cone discs became less important in the last couple of years, the processes continuous generating gear grinding, discontinuous profile grinding and honing of tooth flanks gain rising importance. The analyses of the processes include functionality, the development status, respectively, maturity as well as identifiable trends. Process superior aspects like dressing of the grinding wheel and honing rings and the problem of grinding burn will be considered and evaluated separately.     

How low can you go? The effect of low resolutions on shot types in mobile TV

The advent of mobile TV which is often viewed on small screens with low resolution has made TV content producers think about refraining from using shots that depict subjects from a great distance. Shot types where the object of interest fills the screen are deemed to be more appropriate for mobile devices. This paper reports a study on how shot types used in regular broadcast television are affected when shown on mobile devices at reduced levels of resolution. Seventy-two native speakers judged the acceptability of four different content types at four resolutions (240?×?180, 208?×?156, 168?×?126, 120?×?90). The results show that acceptability of shot types depends on the content and the resolution. Extreme long shots of football content were only less acceptable than other shot types at resolutions smaller than 240?×?180. The medium shot which portrays the upper half of a subject’s body was the most acceptable for news content but for football content was judged worse than shot types that showed less detail. Our results suggest that for a young audience extreme long shots may be used with no detrimental effect for resolutions of 240?×?180 and higher. At lower resolutions and for content with a high degree of dynamism both the medium shot and the extreme long shot might render poorly for the audience. Service providers are well advised to include the results at hand to customize content in terms of shot type use for their audience that will watch the content at very low resolutions. Further research should assess older audiences and the effectiveness of cropping schemes that zoom in on part of the content for low target resolutions.     

Pinch analysis for cooling towers

Optimizing the operation of a power plant with respect to the so-called “cold end” allows for a higher overall efficiency. Among other methods it also requires the proper adaptation of the mass flow rate of the cooling water. In this paper a pinch analysis with respect to heat and mass transfer has been applied to find the optimum mass flow rate for the cooling tower.