蒸发式冷凝器应用于海水淡化系统的试验

将蒸发式冷凝器应用于海水淡化装置中,并作为热源对海水进行加热加湿,将蒸发器作为冷源对海水降温除湿,通过建立试验台,测试海水淡化装置的性能,研究海水入口温度和空气入口湿球温度对海水淡化装置性能的影响因素。试验表明:在喷淋水量为125kg/h,空气入口湿球温度为19.3℃,海水入口温度为32℃时,系统淡水产量可以稳定达到2.5kg/h。这种海水淡化装置的电耗率最小可以达到0.18kW·h/kg,是一种高效、节能并适合家庭用的小型海水淡化系统。     

海水及浓盐水烟气脱硫试验研究

采用喷淋空塔对海水及海水淡化浓盐水的脱硫效率进行了研究。综合考虑了SO2质量分数、液气比、温度和流量等因素对海水烟气脱硫效率的影响,重点比较了海水、蒸馏法浓盐水和反渗透浓盐水的脱硫效率,并对塔底吸收液的温度、pH值、SO32-及SO42-质量分数的变化进行了考察。试验表明SO2质量分数、液气比对海水烟气脱硫影响显著,而温度、气体流量对脱硫效果影响较小。当液气比为9.6 L/m3、气体停留时间为3.08 s,SO2浓度小于1 000×10-6时,海水、蒸馏法和反渗透法浓盐水的脱硫率均在95%以上。     

机械压汽蒸馏海水淡化系统的实验研究

作者对机械压汽蒸馏海水淡化系统进行了实验研究。实验系统主要由蒸发．冷凝器、压缩机和预热器组成,其核心部件为蒸发．冷凝器。系统的蒸发．冷凝器是由85根铜管构成的立式热交换器,离心压缩机的电机功率为1．1kW,预热器由两个面积分别为2．2m^2和3．6m^2的板式换热器构成,分别用于回收冷凝水和浓盐水的显热以预热海水。通过实验研究了蒸发温度、盐水浓度等主要参数对淡水产量的影响和单位电能的产水量。实验结果表明最佳工况下淡水的总能耗为16．6kWh/m^3。     

真空膜蒸馏浓缩反渗透浓盐水的工艺研究

分别采用聚乙烯、聚丙烯微孔膜对反渗透海水淡化浓盐水进行真空膜蒸馏的研究。考察了膜下游真空度、浓盐水温度、浓度、流速对膜通量及截留率的影响。结果表明,真空度增大,膜通量和截留率呈增长趋势。料液温度升高,膜通量增加,截留率呈减少趋势。料液流速增加会使通量增加,截留率呈减少趋势,但影响相对不大。随着料液浓度的增加,膜的通量下降,截留率基本保持不变。本实验条件下最大截留率可达99．99％,表明利用真空膜蒸馏技术可有效实现反渗透海水淡化浓盐水的浓缩。     

(一)蒸馏法

海水淡化技术中的蒸馏法,也叫蒸发法,是一种从盐水溶液中分离淡水的古老方法。当盐水沸腾时,溶解盐残留,而淡水以蒸汽形态从盐水中逸出。在一个蒸馏过程中,包括两个方     

10t/d船用板式蒸馏海水淡化装置性能测试与模拟计算

建立了一套船用板式蒸馏海水淡化装置试验测试平台,对10 t/d淡化装置进行了性能测试,在测试所采用的海水及热水流量下,热水温度由59℃升高至83.77℃,淡水产量由400 L/h提高至550 L/h,进一步提高热水温度,淡水产量提高趋于平缓,操作时热水温度不宜超过85℃;随热水流量的增大,淡水产量呈现先升高后降低趋势;海水入口温度升高造成冷凝器中传热温差降低,真空度降低,产水量下降;海水流量是制约海水淡化装置真空度的关键因素,作为真空喷射泵的驱动水,当海水流量低于一定值时,淡化机真空度急剧下降,几乎不能出水。对板式蒸馏海水淡化装置进行了理论模拟,模拟结果与试验测试数据吻合良好。     

基于吸附/解吸原理的海水淡化中试系统运行研究

基于吸附/解吸原理,研制出了1套淡水产量为100kg/h的海水淡化实验系统,研究了流过吸附/解吸床的供回水温差和冷凝侧和蒸发侧压差随时间的变化关系,解吸床热水供回水温度和流量、吸附床冷却水流量等对系统产水率的影响.结果表明,解吸床热水供水温度和流量对淡水产率有显著影响.当进入解吸床的热水体积流量保持40 m3/h不变,...     

多级喷雾闪蒸海水淡化系统性能分析及响应面优化研究

喷雾闪蒸技术因其能耗低、分离效果好、冷却能力高的特点成为解决淡水资源紧缺的有效方法之一。在喷雾辅助低温脱盐技术的基础上,展开系统内部热和质量平衡的热力学计算,研究喷雾闪蒸系统运行级数和顶值盐水温度对闪蒸效果的影响。研究结果表明,更高的顶值盐水温度可以显著提高生产效率,当顶值盐水温度为363 K时,生产率为3.325 kg/s,性能比为0.627。采用响应面法对喷雾闪蒸系统进行优化,确定系统的最佳运行条件以及各响应的模型关系,获得系统淡化的最佳参数：顶值盐水温度343 K,海水进口流量10 kg/s,冷却水进口温度303 K,冷却水进口流量9.5 kg/s。     

高浓缩倍率低温多效蒸馏海水淡化阻垢研究

模拟低温多效蒸馏装置水平管降膜蒸发条件,进行海水淡化高浓缩倍率条件下阻垢技术研究。实验利用滴定法和原子吸收分光光度计法,考察了不同操作条件下钙镁等易结垢离子浓度变化,并对形成的垢样收集处理后进行场发射扫描电子显微镜及能谱仪测试分析,得到垢物晶型形貌及其元素组成。结果表明:在蒸发温度40—80℃,盐水质量分数5%—8%(质量分数),阻垢剂添加量0—8 mg/L条件范围内,钙离子损失率随着蒸发温度和盐水质量分数的升高而增加,随着阻垢剂添加量的增大而减小。过程产生的垢主要成分为碳酸钙,另有少量氢氧化镁和硫酸钙。在提高海水浓缩倍率条件下,低温多效蒸馏装置结垢趋势更明显,可通过添加适量阻垢剂和定期药剂清洗来控制。     

海水淡化蒸馏法

淡化技术中最早采用的方法是蒸馏法,又称蒸发法。其过程的特点是:盐水(在此为海水、咸水、或其他水溶液的总称)沸腾逸出蒸汽,蒸汽受冷凝为淡水,而原水中的不挥发物浓缩直至最后排放。蒸发法与膜法或冷冻法不同,一经蒸发所得的水就是“蒸馏水”,一般水质都较高,含盐量(总固溶物)可降到10—20毫克/升以下。另一方面,蒸馏法所能处理的原料水比其他方法广泛。原水含盐量从几百毫克/升到     

充碳塑料管壳式增湿-去湿淡化装置及过程:模拟和实验研究

The modelling and experimental investigation of a thermally coupled humidification-dehumidification desalination process using a carbon-filled-polypropylene shell-tube column are presented. A heat/mass transfer model is established to study the correlation among productivity, thermal efficiency, physicochemical parameters (gas/liquid phase temperature, heat/mass transfer coefficient, Reynolds number etc.), and operating conditions (the temperature of feed water, the flow rates of external steam, feed water, and carrier air); at the same time, the effects of operating conditions on the productivity and thermal eficiency of the column are investigated both theoretically and experimentally, which indicate that the optimum flow rates of external steam, feed water, and carrier gas are 0.18, 60, and 10kg·h-1, respectively, and the higher the feed water temperature (≤95℃) is, the greater the productivity and the thermal efficiency will be. Furthermore, performance comparison with the previous study shows that the condensate productivity of this carbon-filled-plastic column is not lower than that of the copper column, which demonstrates the practicability and feasibility of applying such a plastic column to the humidification-dehumidification desalination process.     

Energy advantages of reverse osmosis in seawater desalination

The very rapid increase in energy costs during the past three years is causing a change in the preferred process technology for seawater desalination. The phase changes, evaporation, and condensation, required in the distillation processes make them more energy intensive than the ambient temperature liquid separation that occurs in the reverse osmosis (RO) process. This paper describes the RO process and how to calculate its energy consultation.The RO process requires only 5–7 KWh/m³ of product water compared to 15–16 KWh/m³ required by the most efficient distillation process. The productivity of a large dual purpose electricity/RO water plant is compared to the productivity of a commercially purchased state-of-the-art dual purpose electric/distillation water plant that is currently under construction. The RO potable water productivity is about 2X the distillate flow at the same fuel rate     

竖管多效蒸发海水淡化系统的启动特性

建立大型竖管多效蒸发海水淡化系统的动态启动控制模型,通过数值分析研究,对系统的启动过程和启动特性进行理论探索.分析了初始原料海水流量以及最高饱和温度等运行参数的选择对系统启动过程的影响.研究了启动阶段,原料海水流量与系统的造水比以及启动时间之间的耦合影响;计算结果为原料海水流量的优化提供了依据.研究还表明,在启动之初,系统即可稳定地承担作为热源的低温核供热堆的额定产热量,显示该系统和核供热堆具有良好的耦合特性.建立的启动模型在经过实验验证加以完善之后,可以作为分析系统动态运行特性的理论基础.     

高回收率反渗透海水淡化工艺

目前反渗透海水淡化的回收率小于40％。本文研究开发死端超滤预处理技术和反渗透一纳滤联合脱盐相结合的膜集成海水淡化新工艺,与传统工艺比较,具有装置体积小,产水回收率高等优点。文章介绍了采用新工艺的海水淡化装置样机的试制情况及现场运行结果。沿岸海水为料液,操作压力1为5．1MPa条件下,操作压力2为2.0MPa条件下,装置脱盐率99．21％,产水量3971.3L/h,产水回收率55％。海水淡化装置对海水中Ca^2 、Mg^2 、Na^ 、HCO3^-、Cl^-、SO4^2-、TDS,总碱度,总硬度的脱除率分别为99％,99．6％,99．21％,95％,99．35％,98．48％,99.21％,95％,99．42％。     

Experimental investigation of a baffled shell and tube desalination column using the humidification-dehumidification process

The humidification-dehumidification process is an interesting technique that has been adapted for water desalination. Most previous work performed the humidification-dehumidification desalination process in two separate columns, which increases the complexity of the system and limits the humidification effect of the carrier gas as well as the thermal efficiency of the process. In this work, a baffled shell and tube desalination unit was built to perform humidification and dehumidification simultaneously at the tube and shell side of the column, respectively. The effects of several operating conditions on the production and thermal efficiency of the process were investigated, including water flow rate, inlet water temperature, carrier gas flow rate and external steam flow rate. The results show that the productivity and thermal efficiency of the process both increase with increasing inlet water temperature. Suitable flow rates exist for both the water and carrier gas, which are 6–30 kg h⁻¹ and 4–20 kg h⁻¹ for the present column, respectively. The increase of external steam flow rate increased the productivity but decreased thermal efficiency of the process. A further performance comparison with a previous unbaffled desalination unit indicated that the baffle plates significantly enhance the productivity of the column, which is usually 3–6 times that of the unbaffled one. Meanwhile, the salinity of the produced water was determined to be in the range of 20–30 mg/L with the feed water containing 10,000 mg/L NaCl.     

Solar desalination using humidification—dehumidification technology

A numerical study has been carried out to investigate the performance of a simple solar desalination system using humidification—dehumidification processes. The desalination system consists of a solar air heater, humidifier, dehumidifier and a circulating air-driving component. The study covers the influence of different environmental, design, and operational parameters on the desalination system productivity. Environmental parameters include solar intensity, ambient temperature and wind speed. Design parameters include the solar heater base insulation, the humidifier and the dehumidifier effectiveness. Operational parameters include air circulation flow rate, feed water rate and temperature. The results indicated that the solar air heater (energy source) efficiency significantly influences system productivity. Increasing the solar intensity and ambient temperature and decreased wind velocity increases system productivity. Increasing the air flow rate up to 0.6 kg/s increases the productivity, after which it has no significant effect. The feed water flow rate has an insignificant influence on system productivity. The surprising result is that the dehumidifier effectiveness has an insignificant influence on system productivity, which has a very important implication for the system's economy. The physical explanation of this finding is given.     

减压多效膜蒸馏过程试验研究

针对膜蒸馏(MD)过程能耗高、蒸汽冷凝耗水量大的问题,首次设计了减压多效膜蒸馏过程(MEMD)。其特征是在减压膜蒸馏(VMD)过程中设立特殊的多效蒸发区。其中的膜组件同时具有蒸汽的换热降温与原料液的升温蒸发双重作用,从而实现VMD过程蒸发潜热的高效回收利用。试验研究了主蒸发区膜组件面积、多效蒸发区组件管程的进液流量、多效蒸发区组件长度等参数对MEMD过程性能的影响。当主蒸发区膜组件面积为0.10 m2、多效蒸发区组件长度为868 mm、管程进液体积流量为4.0 L/h时,系统的当量膜通量最大(34.8 kg/(m2.h)),额外冷却水用量仅为传统VMD过程的30.8%(每L产水消耗17.2 L冷却水);增加多效蒸发区的组件长度,能显著提高蒸汽相变热回收率,但不能提高系统的当量膜通量。     

乙烯焦油精馏过程的模拟

利用化工过程模拟软件Aspen plus,模拟了乙烯裂解焦油的精馏过程,优化了各精馏塔的馏出率、回流比、进料板位置、进料温度等参数,可减少能量消耗13．9％。