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一种新型家用太阳能海水淡化装置 总被引:1,自引:1,他引:0
设计了一种具有折皱底面的多级迭盘式家用太阳能海水淡化装置。该装置由热管式真空集热管和多级海水淡化器两部分组成。在实际天气条件下,对该装置性能进行了测试,给出了该装置每0.5 h的产水量、累计产水量以及各级水盘的水温随运行时间的变化曲线。实验结果表明,在测试当天累计太阳辐射量22.46 MJ/(m^2.d)条件下,该装置产水量可达9.34 kg/(m^2.d),单位太阳辐射能产水量为1.50 kg/kWh;该装置的性能系数达到0.956,是传统单级盘式太阳能蒸馏器性能系数的2.7倍。该装置使用简便,运行可靠,维护费用低,在淡水缺乏的岛屿或偏远的咸水湖地区,是一种较为理想的家用太阳能海水淡化装置。 相似文献
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太阳能蒸馏器中一组传热传质关系式 总被引:3,自引:0,他引:3
建立了盘式太阳能蒸馏器中一组传热传质关系式,并用多级迭盘式蒸馏室进行稳态模拟实验。发现该关系式在较大的雷利数范围及较宽的温度段内能很好地预示蒸馏器的产水量。 相似文献
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文章针对常压运行单级太阳能蒸馏器产水效率较低的问题,提出了嵌套管回热和负压运行的改进方案。改进装置由多层圆管嵌套而成,其内部具有多个独立拱形产水腔室,在负压下运行时具有能耗低、操作维护简便、产水性能好且水质高等特点。分别于成都和西昌两地测试了装置处于95(常压),60,40,20 kPa运行压力时的产水性能,结果表明装置在西昌维持40 kPa运行时具有最优产水性能,对应单日产水量为7.2 kg/m2,性能系数为1.45,较常压运行时性能提升近一倍。此后对装置维持负压的能耗数据及产水经济性进行了评估,数据表明装置产水时维持负压能耗低于4 kJ/kg,综合产水成本约为0.1元/L,与同类太阳能蒸馏器相比具有一定优势。 相似文献
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多级降膜式太阳能蒸馏器的模拟实验研究 总被引:5,自引:2,他引:3
用热水作为供热热源,对一台小型多级降膜式蒸馏器进行模拟实验研究。介绍了实验装置,给出了不同条件下的产水量。研究了蒸发-凝结板偏离铅垂线的角度θ与产水量同蒸馏器单级和四级时的比产水率曲线。 相似文献
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横管降膜蒸发内回热式太阳能海水淡化装置的实验研究 总被引:5,自引:5,他引:5
设计建造了一台利用太阳能或其它余热驱动的横管降膜蒸发内回热式海水淡化装置,并利用模拟热源对该装置进行了实验研究,由于在系统的蒸发及冷凝过程中,大部分水蒸汽的凝结潜热被重复利用于海水的预热及蒸发过程,因而系统具有较高的产水率,同时,由于在气流的闭式环过程中,蒸发腔中处于负压状态,冷凝腔中处于正压状态,强化了系统的产水性能,使系统的产水效率比传统的盘式太阳能蒸馏器提高了3倍左右,介绍了系统的瞬态特性及运行温度,供海水流率与产水量的相互关系,对影响系统产水率的其它因素进行了讨论。 相似文献
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工业化太阳能苦咸水淡化装置占地面积大、初始投资高,难以应用于分布式户用苦咸水淡化过程。文章设计了一种户用多效太阳能苦咸水蒸馏器,该蒸馏器具有占地面积小、低品位热能驱动、运行简单等特点,可以实现分布式制备淡水。文章在实际天气条件下,测试了由平板太阳能集热器供能的户用多效太阳能苦咸水蒸馏器的产水速率,研究了该蒸馏器蒸发冷凝温度的变化情况,以及竖直方向冷凝温度梯度的分布情况。研究结果表明,晴天稳态运行时,户用多效太阳能苦咸水蒸馏器内蒸发冷凝温差的最大值约为22℃,沿竖直方向第一效冷凝套筒的冷凝温差约为9.8℃,该蒸馏器的最大产水速率为23.53 g/min,可以满足偏远地区小型户用淡水的制备需求。 相似文献
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设计制造一种以太阳能等低温热源驱动,并在负压下运行的两级管式淡化脱盐装置。在44及62℃恒温热源加热条件下,测试装置处于101、60及20 kPa运行压力时的水温及淡水产率,对其性能进行评估。结果表明负压运行可使蒸馏系统产水率提高到常压运行时的3倍以上,同时可提升装置对热能的利用效率。此外,数据表明真空辅助技术应用于小型淡化装置时,电能消耗较低,操作压力为60及20 kPa时,真空泵每小时耗电量分别约为0.00035及0.009 kWh。结合实验数据对2~5级管式蒸馏器的能量利用效率进行估算,当热源温度为70℃时,5级蒸馏器性能系数在60 kPa负压下可达3.79。 相似文献
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《太阳能学报》2021,(8)
为提高小型太阳能海水蒸馏器热能利用效率和产水速率,设计一种管式降膜太阳能海水蒸馏器,基于小高径比环形封闭空间水蒸气传热传质特性,分析特征尺寸和运行温度对装置单位冷凝面积产水速率的影响机理,研究不同特征尺寸管式降膜太阳能海水蒸馏器蒸发冷凝温差、竖直方向冷凝温度梯度等变化规律。结果表明,运行温度为85℃时,特征尺寸为0.015 m的管式降膜太阳能海水蒸馏器单位冷凝面积产水速率为0.696 kg/(h·m~2),比特征尺寸为0.035 m的蒸馏器增加10.48%,冷凝温度T_4为81.94℃,比特征尺寸为0.035 m的蒸馏器高3.83℃,在测试范围内蒸发冷凝温差最小为1.9℃,该研究可为强化管式太阳能海水淡化装置热质传递过程提供技术参考。 相似文献
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Woody biomass in Finland and Sweden comprises mainly four wood species: spruce, pine, birch and aspen. To study the ash, which may cause problems for the combustion device, one tree of each species were cut down and prepared for comparisons with fuel samples. Well-defined samples of wood, bark and foliage were analyzed on 11 ash-forming elements: Si, Al, Fe, Ca, Mg, Mn, Na, K, P, S and Cl. The ash content in the wood tissues (0.2–0.7%) was low compared to the ash content in the bark tissues (1.9–6.4%) and the foliage (2.4–7.7%). The woods’ content of ash-forming elements was consequently low; the highest contents were of Ca (410–1340 ppm) and K (200–1310), followed by Mg (70–290), Mn (15–240) and P (0–350). Present in the wood was also Si (50–190), S (50–200) and Cl (30–110). The bark tissues showed much higher element contents; Ca (4800–19,100 ppm) and K (1600–6400) were the dominating elements, followed by Mg (210–2400), P (210–1200), Mn (110–1100) and S (310–750), but the Cl contents (40–330) were only moderately higher in the bark than in the wood. The young foliage (shoots and deciduous leaves) had the highest K (7100–25,000 ppm), P (1600–5300) and S (1100–2600) contents of all tissues, while the shoots of spruce had the highest Cl contents (820–1360) and its needles the highest Si content (5000–11,300). This paper presented a new approach in fuel characterization: the method excludes the presence of impurities, and focus on different categories of plant tissues. This made it possible to discuss the contents of ash element in a wide spectrum of fuel-types, which are of large importance for the energy production in Finland and Sweden. 相似文献
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《热能动力工程》2014,(5)
正1 ABSTRACT To reduce the effect of global warming on our climate,the levels of CO2emissions should be reduced.One way to do this is to increase the efficiency of electricity production from fossil fuels.This will in turn reduce the amount of CO2emissions for a given power output.Using US practice for efficiency calculations,then a move from a typical US plant running at 37%efficiency to a 760℃/38.5 MPa(1 400/5 580 psi)plant running at 48%efficiency would reduce CO2emissions by 170kg/MW.hr or 25%. 相似文献
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The purpose of this paper is to illustrate the advantages of the direct surface-curvature distribution blade-design method, originally proposed by Korakianitis, for the leading-edge design of turbine blades, and by extension for other types of airfoil shapes. The leading edge shape is critical in the blade design process, and it is quite difficult to completely control with inverse, semi-inverse or other direct-design methods. The blade-design method is briefly reviewed, and then the effort is concentrated on smoothly blending the leading edge shape (circle or ellipse, etc.) with the main part of the blade surface, in a manner that avoids leading-edge flow-disturbance and flow-separation regions. Specifically in the leading edge region we return to the second-order (parabolic) construction line coupled with a revised smoothing equation between the leading-edge shape and the main part of the blade. The Hodson–Dominy blade has been used as an example to show the ability of this blade-design method to remove leading-edge separation bubbles in gas turbine blades and other airfoil shapes that have very sharp changes in curvature near the leading edge. An additional gas turbine blade example has been used to illustrate the ability of this method to design leading edge shapes that avoid leading-edge separation bubbles at off-design conditions. This gas turbine blade example has inlet flow angle 0°, outlet flow angle −64.3°, and tangential lift coefficient 1.045, in a region of parameters where the leading edge shape is critical for the overall blade performance. Computed results at incidences of −10°, −5°, +5°, +10° are used to illustrate the complete removal of leading edge flow-disturbance regions, thus minimizing the possibility of leading-edge separation bubbles, while concurrently minimizing the stagnation pressure drop from inlet to outlet. These results using two difficult example cases of leading edge geometries illustrate the superiority and utility of this blade-design method when compared with other direct or inverse blade-design methods. 相似文献
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A chemical reactor for the steam-gasification of carbonaceous particles (e.g. coal, coke) is considered for using concentrated solar radiation as the energy source of high-temperature process heat. A two-phase reactor model that couples radiative, convective, and conductive heat transfer to the chemical kinetics is applied to optimize the reactor geometrical configuration and operational parameters (feedstock's initial particle size, feeding rates, and solar power input) for maximum reaction extent and solar-to-chemical energy conversion efficiency of a 5 kW prototype reactor and its scale-up to 300 kW. For the 300 kW reactor, complete reaction extent is predicted for an initial feedstock particle size up to 35 μm at residence times of less than 10 s and peak temperatures of 1818 K, yielding high-quality syngas with a calorific content that has been solar-upgraded by 19% over that of the petcoke gasified. 相似文献
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The physical aspects of the activation energy, in higher and high temperatures, of the metal creep process were examined. The research results of creep-rupture in a uniaxial stress state and the criterion of creep-rupture in biaxial stress states, at two temperatures, are then presented. For these studies creep-rupture, taking case iron as an example the energy and pseudoenergy activation was determined. For complex stress states the criterion of creep-rupture was taken to be Sdobyrev's, i.e. σred = σ1 β + (1 − β)σi, where: σ1-maximal principal stress, σi-stress intensity, β-material constant (at variable temperature β = β(T)). The methods of assessment of the material ageing grade are given in percentages of ageing of new material in the following mechanical properties: 1) creep strength in uniaxial stress state, 2) activation energy in uniaxial stress state, 3) criterion creep strength in complex stress states, 4) activation pseudoenergy in complex stress states. The methods 1) and 3) are the relatively simplest because they result from experimental investigations only at nominal temperature of the structure work, however, for methods 2) and 4) it is necessary to perform the experimental investigations at least at two temperatures. 相似文献
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Jaime Massanet-Nicolau Alan Guwy Richard Dinsdale Giuliano Premier Sandra Esteves 《International Journal of Hydrogen Energy》2010
Hydrogen was produced from primary sewage biosolids via mesophilic anaerobic fermentation in a continuously fed bioreactor. Prior to fermentation the sewage biosolids were heated to 70 °C for 1 h to inactivate methanogens and during fermentation a cellulose degrading enzyme was added to improve substrate availability. Hydraulic retention times (HRT) of 18, 24, 36 and 48 h were evaluated for the duration of hydrogen production. Without sparging a hydraulic retention time of 24 h resulted in the longest period of hydrogen production (3 days), during which a hydrogen yield of 21.9 L H2 kg−1 VS added to the bioreactor was achieved. Methods of preventing the decline of hydrogen production during continuous fermentation were evaluated. Of the techniques evaluated using nitrogen gas to sparge the bioreactor contents proved to be more effective than flushing just the headspace of the bioreactor. Sparging at 0.06 L L min−1 successfully prevented a decline in hydrogen production and resulted in a yield of 27.0 L H2 kg−1 VS added, over a period of greater than 12 days or 12 HRT. The use of sparging also delayed the build up of acetic acid in the bioreactor, suggesting that it serves to inhibit homoacetogenesis and thus maintain hydrogen production. 相似文献
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As part of a pilot study investigating the role of microorganisms in the immobilisation of As, Sb, B, Tl and Hg, the inorganic geochemistry of seven different active sinter deposits and their contact fluids were characterised. A comprehensive series of sequential extractions for a suite of trace elements was carried out on siliceous sinter and a mixed silica-carbonate sinter. The extractions showed whether metals were loosely exchangeable or bound to carbonate, oxide, organic or crystalline fractions. Hyperthermophilic microbial communities associated with sinters deposited from high temperature (92–94°C) fluids at a variety of geothermal sources were investigated using SEM. The rapidity and style of silicification of the hyperthermophiles can be correlated with the dissolved silica content of the fluid. Although high concentrations of Hg and Tl were found associated with the organic fraction of the sinters, there was no evidence to suggest that any of the heavy metals were associated preferentially with the hyperthermophiles at the high temperature (92–94°C) ends of the terrestrial thermal spring ecosystems studied. 相似文献