共查询到20条相似文献,搜索用时 62 毫秒
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海水淡化是利用海水脱盐生产淡水的技术和过程。多效蒸馏海水淡化原理是高温蒸汽或热水与海水进行热交换,海水被加热,蒸发出的水蒸气冷凝得到淡水,但其结垢和腐蚀问题比较严重。低温多效蒸馏是多效蒸馏技术的一种改进技术,操作温度较低,避免和减轻了海水对设备造成的腐蚀与结垢问题, 相似文献
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本文介绍已获国家专利(申请号:98214899.2)的太阳能海水淡化设备。设备利用高效太阳能集热技术加热海水,利用真空减压技术收集水蒸汽制备淡水,该设备是一种适于为缺乏淡水的海边和岛屿生活的人们提供淡水的处理设备。 相似文献
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With an ever-increasing population and rapid growth of industrialization, there is great demand for fresh water. Desalination has been a key proponent to meet the future challenges due to decreasing availability of fresh water. However, desalination uses significant amount of energy, today mostly from fossil fuels. It is, therefore, reasonable to rely on renewable energy sources such as solar energy, wind energy, ocean thermal energy, waste heat from the industry and other renewable sources. The present study deals with the energy-efficient seawater desalination system utilizing renewable energy sources and natural vacuum technique. A new desalination technology named Natural Vacuum Desalination is proposed. The novel desalination technique achieve remarkable energy efficiency through the evaporation of seawater under vacuum and will be described in sufficient detail to demonstrate that it requires much less electric energy compared to any conventional desalination plant of fresh water production of similar capacity. The discussion will highlight the main operative and maintenance features of the proposed natural vacuum seawater desalination technology which seems to have promising techno-economic potential providing also advantageous coupling with renewable energy sources. 相似文献
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A growing population with depleting water resources has increased the requirement for desalination systems. Large-scale desalination plants have seen a growth in the recent period; however, the small-scale (SS) decentralized desalination plants' need has not been realized for the rural population. Low specific heat consumption for multieffect desalination systems makes it suitable for such decentralized operation. The challenge now lies in determining the system capacity and optimal operational range for the SS requirements. In this study, the thermoeconomic model for an SS multieffect desalination system for various configurations is developed. Optimization of the SS plant for the number of effects is performed to determine the optimal operational range of motive steam pressure, motive steam flow rate, and feed water flow rate. Total distillate production and freshwater cost are focused on objectives and constraints imposed over the input parameters with SS production. The results reveal that for a distillate production of 750 L/day, the motive steam flow requirement is estimated to be 25–35 kg/h with a pressure range of 2–5 bar. This study provided an overview for selecting the number of effects based on the commercial aspect of total production requirements. 相似文献
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《Solar Energy》2013
This work represents the efficiency of a solar desalination pond as a second stage of proposed zero discharge desalination processes to reach fresh water and also concentrated brine from the effluent wastewater of the desalination unit of Mobin petrochemical complex. So a solar desalination pond is constructed after a pretreatment unit to concentrate the softened wastewater to about 20 wt%. The concentrated wastewater is as a suited feed for a forced circulation crystallizer. During one year, the effects of major parameters such as ambient temperature and solar insolation rate are investigated, experimentally. specific gravity in each layer of concentrated brine wastewater is evaluated. Also, evaporation rates are calculated theoretically and are verified by experimental data. Theoretical values predict evaporation rate accurately. Results show good agreement with experimental data. According to results, maximum evaporation rate is 5 l/m2 day when the insolation rate is about 24,602 kJ/m2 day Solar energy absorption factor on June is max. Also, experimental results show the best proposed time to gain highest thermal energy is on spring therefore performance efficiency of solar desalination pond promote on spring comparing with the other months. Extracted data for specific gravity prove the bottom of solar desalination pond, layer 1, is best zone for energy saving and energy utilization.Also, theoretical values of evaporation rate are calculated according to measured temperatures and related mass conservation equation. Comparison between theoretical and experimental values shows dusty weather, humidity and wind velocity affects on heat transfer coefficients approximately. So, deviations between theoretical data and measured values can be explained. Results show good agreements with experimental data. 相似文献
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A wastewater desalination system based on a low‐temperature air source heat pump was developed and studied in this paper. The system consists of 2 main parts: the wastewater flow process and the heat pump cycle. A series of experiments were conducted on the system under different conditions, and the effect of the evaporation temperature was investigated. This system can reach equilibrium at any evaporation temperature using the combination of the compressor and vacuum pump. To treat wastewater with low boiling point organic matter, the system was operated at a low evaporation temperature of 48°C. The organic matter remained in the concentrated wastewater, and the organic removal was approximately 97%. Three kilograms of treated water was produced in 1 hour with an energy consumption of 250 W. The performance ratio (PR) obtained from the experiments ranged from 4.6 to 7.3. The cost for treating 1 kg of water was 0.038 yuan CNY assuming 0.5 yuan CNY per kWh at the compressor frequency of 50 Hz. 相似文献
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This study presents a thermal and economic performance analysis of a LT-MEE (low-temperature multi-effect evaporation) water desalination system coupled with an LiBr-H2O ABHP (absorption heat pump). A 60-78% water production increase over a stand-alone LT-MEE run at the same heat source conditions can be obtained owing to the coupling. A detailed thermodynamic sensitivity analysis of the ABHP-MEE is performed. Although ABHP is usually considered to be more efficient than an EHP (ejector heat pump), we also compare the thermal performance of the ABHP-MEE with an integrated EHP-MEE system. The results show that the ABHP has a more favorable thermal performance than the EHP only in certain parameters ranges. The reasons and these parameters ranges are discussed. The economic analysis of the ABHP-MEE shows that the capital cost of the ABHP accounts for a very small part of the water cost, and when designing an ABHP for an existing MEE unit, the parameters selection of an ABHP for lower water cost is consistent with that for better thermal performance. The unit steam cost is an important factor in determining whether the ABHP-MEE or the EHP-MEE is economically favorable, with the influence discussed. Also, a recommended general procedure for economic comparison between ABHP-MEE and EHP-MEE is outlined. 相似文献
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K.R. Agha 《Solar Energy》2009,83(4):501-149
The paper discusses optimisation of the size of the pond and the number of stages for three different storage zone temperatures taking into account the large variation in quantity of energy supplied by the pond between summer and winter. One result is that over-sizing the pond, leading to some rejection of the heat collected during the summer (which is referred to as peak clipping), will result in a higher utilisation factor of the desalination plant and a reduction in the summer/winter yield ratio. Optimum peak clipping days, leading to the minimum product water cost, for each storage zone temperature and performance ratio is presented.The sensitivity analysis of the various factors affecting the overall water costs show that the capital costs comprise about two thirds (2/3) of the total desalinated water costs. This demonstrates and re-emphasises the inherent and basic fact that solar desalination is a capital intensive enterprise. Each 1% increase in interest rate increases solar pond thermal energy costs by about 13-15% and desalinated water costs from SP/MSF combination by about 10-13%. 相似文献
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A solar desalination system based on an innovative passive vacuum concept, utilizing low-grade solar heat, was studied experimentally. The system uses the natural means of gravity and atmospheric pressure to create a vacuum, under which liquid can be evaporated at much lower temperatures and with less energy than conventional techniques. A vacuum equivalent to 3.7 kPa (abs) or less can be created depending on the ambient temperature at which condensation will take place. The system consists of a heat source, an evaporator, a condenser, and injection, withdrawal and discharge pipes. The effect of various operating conditions (withdrawal rate, depth of water body and temperature of the heat source) were studied experimentally and compared with theoretical results. The experimental results agreed well with the theoretical predictions. It was found that the effects of withdrawal rate and the depth of water in the evaporator were small while the effect of heat source temperature was significant. 相似文献