Results 1 - 10 of 2099
Results 1 - 10 of 2099. Search took: 0.037 seconds
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[en] When assessing the profitability of desalination plants, it is important that the permselectivity and permeability of the ion exchanger membranes be known. These values were determined for different combinations of membranes by desalination experiments using sodium chloride solutions and a stack of membranes, and the experimental values were compared with values for the apparent permselectivities obtained by membrane potential measurements and with values for permeabilities obtained by diffusion studies using radioactively labelled ions. (orig.)
[de]Fuer die Wirtschaftlichkeit von Entsalzungsanlagen ist die Kenntnis von Permselektivitaet und Permeabilitaet der verwendeten Ionenaustauschermembranen von grosser Bedeutung. Diese Groessen wurden fuer verschiedene Membrankombinationen durch Entsalzungsversuche von Natriumchloridloesungen mit einem Membranstapel ermittelt und mit Werten fuer die scheinbaren Permselektivitaeten verglichen, die ueber Membranpotentialmessungen erhalten wurden, sowie mit Werten fuer Permeabilitaeten, die durch Diffusionsversuche mit radioaktiv markierten Ionen erhalten wurden. (orig.)
[en] The Office of Saline Water (OSW) accomplished a very large amount of significant work related to the design and performance of large heat exchanger bundles and enhanced heat transfer surfaces. This work was undertaken to provide basic technical and economic data for the design of distillation plants for the desalination of seawater, and should be of value to other industrial applications as well. The OSW work covers almost every aspect of heat exchanger design, and ranges academic research to data gathering on commercial desalting plants. Exchanger design configurations include multistage flash plant condensers, vertical tube falling film and upflow evaporators, and horizontal tube spray film evaporators. Unfortunately, the data is scattered through a large number of reports of which many are concerned primarily with factors other than heat transfer, and the quality of reporting and the quality of the data are far from consistent. This report catalogues and organizes the heat exchanger data developed by the OSW. Some analysis as to the validity of the data is made and ranges of performance that can be expected are given. Emphasis is placed on the vertical tube, falling film evaporators. A thorough analysis of the large literature file that was surveyed was not possible. No analysis was made of the quality of original data, but apparent data discrepancies are pointed out where such discrepancies happen to be found
[en] A condenser/evaporator heat exchanger comprising a plurality of vertically oriented panel units spaced moderately from one another is described. Each panel unit comprises a pair of thin film plastic sheets bonded to one another along a plurality of vertically extending bond lines transversely spaced from one another at regular intervals. The two sheets form between adjacent pairs of bond lines a plurality of vertical tubular condensing chambers adapted to receive pressurized steam. Brine is directed onto the outer surfaces of the panel units at the upper ends thereof, the brine descending down the outer surfaces of the panel units to be in heat exchange relationship with the steam inside the tubular condensing chambers
[en] Scientific research and design institute of energy technic (Moscow, Russia) works up the projects of thermal pool reactors RUTA with power 20 and 55 MW for heat delivery of apartment buildings and production premises. The reactors may be use as protected sources of energy for air conditioning or seawater desalination. Variant of underground siting of heat delivery atomic station with reactor RUTA is examined. Calculation studies of worked regimes confirms the high level of safety of heat delivery atomic station with the reactor RUTA. Work analysis of reactor installation RUTA in the central heat delivery systems is showing that for practically all space heating period this reactor is satisfying the standard requirements of heat delivery of buildings
[en] Highlights: • Low-pressure and entrained flow blocked regions inside the ejector are found. • A novel steam ejector with pressure regulation is proposed. • The blocked entrained flow could be dredged by bypass for performance improvement. • There is an optimum combination of pressure regulation schemes. • This technology could be applied to both design and off-design conditions. - Abstract: Steam ejectors are regarded as a promising energy-saving technology, it is thus crucial to enhance its working performance for broader application horizons. In this study, a detailed simulation is made of a design steam ejector used in MED-TVC desalination system. The results discloses that there is actually a large entrained flow blocked region downstream the entraining entrance and significant low-pressure potentials inside the throat and diffuser whose pressure are far lower than that of the blocked region. Based on this finding, a so-called pressure regulation technology is proposed to use these existing pressure differences to dredge the blocked entrained flow, and thus more entrained steam could be drawn into the ejector. Then the feasibility verifications of different pressure regulation schemes are carried out, and a systematic analysis and investigation of their influences on the entrainment performance has been implemented systematically from the mass flow rate and pressure field. The results reveal that there is an optimum combination of pressure regulation schemes to dredge the blocked entrained flow effectively, by which a maximum and considerable entrainment ratio improvement could be achieved, as large as 26.85% in the covered simulations, and with 3.31% even under the design condition. To be specific, the throat-entraining entrance downstream pressure regulation should be adopted if the ejector operates under the design condition, otherwise, the combined-entraining entrance downstream pressure regulation is the best choice.
[en] Interests on predictive or condition-based maintenance are heightening in power industries. The ultimate goal of the condition-based maintenance is to prioritize and optimize the maintenance resources by taking a reasonable decision-making process depending op plant's conditions. Such decision-making process should be able to not only observe the deviation from a normal state but also determine the severity or impact of the deviation on different levels such as a component, a system, or a plant. In order to achieve this purpose, a Plant Health Index (PHI) monitoring system was developed, which is operational in more than 10 units of large steam turbine cycles in Korea as well as desalination plants in Saudi Arabia as a proto-type demonstration. The PHI monitoring system has capability to detect whether the deviation between a measured and an estimated parameter which is the result of kernel regression using the accumulated operation data and the current plant boundary conditions (referred as an empirical model) is statistically meaningful. This deviation is converted into a certain index considering the margin to set points which are associated with safety. This index is referred as a PHI and the PHIs can be monitored for an individual parameter as well as a component, system, or plant level. In order to organize the PHIs at the component, system, or plant level, a success tree was developed. At the top of the success tree, the PHIs nodes in the middle of the success tree, the PHIs represent the health status of a component or a system. The concept and definition of the PHI, the key methodologies, the architecture of the developed system, and a practical case of using the PHI monitoring system are described in this article
[en] Recent developments in membrane technology are made essentially in the field of surface modification in order to tune selectivity and to decrease fouling. In the present study, we investigate the surface modification and the characterization of two thin film composite membranes made of polyamide. The selected membranes belong to Nano filtration with opened pores (GH) and to Ultrafiltration with tight pores (GM). The surface modification of both membranes was made chemically in the first step by grafting acrylic acid and physically in the second step by alternating adsorption of oppositely charged poly electrolytes. The active surfaces of the bare commercial membranes and of the modified ones were morphologically characterized by atomic force microscopy; and by FTIR-ATR. Desalination performances of these membranes were determined with synthetic salt solutions with different ion valences before and after surface modification. Hydraulic permeability of NF membranes dropped for all salt solutions. Retention rate of salt solutions containing divalent cations is reduced while those containing divalent anions and monovalent ions have seen their retention rate increased. With UF membranes, hydraulic permeability is increased globally. Retention of salt solutions containing divalent anions is improved whereas retention of salts with divalent cations and monovalent ions is decreased.