The Development and Application of a Small-Scale Organic Rankine Cycle for Waste Heat Recovery

Power conversion systems based on organic Rankine cycles have been identified as a potential technology especially in converting low-grade waste heat into electricity as well as in small-scale biomass, solar, or geothermal power plants. The theoretical analysis can guide the ORC design, but cannot predict accurately the system performance. Actually, the operation characteristics of every component have a vital effect on the system performance. This chapter presents the detailed operation characteristic of a small-scale ORC. The effects of the operation parameters, the mixture working fluid and the operation strategy on system overall performance are addressed. It can be concluded that improving the system overall performance should give priority to increase the pressure drop. Whether the mixtures exhibit better thermodynamic performance than the pure working fluids depend on the operation parameters and mass fraction of mixtures. The mixture working fluids obtain a higher expander shaft power but a relatively higher BWR. The expander rotating speed for standalone operation strategy keeps rising from 2320 to 2983 rpm, whereas that of grid connect operation strategy keeps constant of 3600 rpm

Cellular Automaton for Simulation of Oxide Layer Growth Influenced by Chromium Concentration of Structure Material

Chromium, an important alloying element, has been added in ferrous and nickel based alloy such as stainless steels and Inconel alloy to improve the corrosion resistance. High corrosion resistance of structural materials in extremely high working temperature is one crucial R&D objective of Gen IV nuclear power plants which propose to raise the thermal efficiency via high working temperature. A cellular automaton (CA) model based on the stochastic approach was proposed to simulate the process of oxidation and corrosion of structural material in flowing fluid. The relation of chromium concentration against oxide layer thickness during a specific period was found. The material containing a specific amount of chromium content shows the thinnest oxide layer on its surface, which shows the strongest ability of corrosion resistance The result of simulation is close to that of experiments, which demonstrates that the CA model will have potential to achieve the goal of this kind of study. Moreover, it not only brings the benefit to save considerably experimental time and resources but also helps researchers to find out the optimized chromium content for the best corrosion resistance

Numerical modeling of high temperature bayonet heat exchanger and decomposer for decomposition of sulfur trioxide

Motivation Hydrogen is an attractive energy carrier in the future energy technology. Hydrogen is produced from splitting of water through various process namely electrolysis, photo-electrolysis, photo-biological production and thermochemical water-splitting. The aim of this study is to numerically investigate fluid flow, heat transfer and chemical reaction in bayonet high temperature heat exchanger and decomposer. Parametric studies are performed to achieve maximum decomposition with less pressure drop

Torsion of right middle lobe after a right upper lobectomy

Lobar torsion after lung resection is a quite rare complication. A 50-year-old woman presented typical features on chest radiographs and CT(computed tomography) scan of lobar torsion after a right upper lobectomy. After emergency lobectomy of right middle lobe, the patient recovered well and discharged 10 days after the second operation