淡化浓海水自然蒸发速度影响规律研究

针对当前气象因素(辐照强度、风速、空气温度和相对湿度)与卤水因素(卤水温度)作用于卤水蒸发速率定量研究的数据缺乏等问题,本研究采用室内蒸发模拟系统及信号采集系统相结合的实验方法,以气候条件为依据,进行了淡化浓海水自然蒸发的模拟实验。采用统计学中的分析方法,对实验数据进行分析。结果表明卤水蒸发速率随辐照度、风速的增加呈线性增加以及相对湿度的增加呈线性减小,随卤水温度和环境温度呈2次曲线增加。     

西台吉乃尔盐湖析钾老卤及冻卤25 ℃等温蒸发实验研究

为了有效利用西台吉乃尔盐湖析钾后老卤及冻卤中的锂、硼等元素,对西台吉乃尔盐湖析钾后老卤和冻卤展开了25 ℃等温蒸发实验,采用化学分析、X射线粉晶衍射等方法对析出固体矿物的含量及物相进行了分析,并依据Li⁺,Mg²⁺∥Cl^-,SO₄^2-—H₂O四元体系25 ℃介稳相图对盐类析盐路线进行了理论分析。结果表明,析钾老卤蒸发过程主要析出钠石盐、光卤石、水氯镁石、四水泻盐和一水硫酸锂,其中Li⁺富集到5.4 g/L左右时开始析出锂盐,而硼富集到46.73 g/L时仍无明显析出;冷冻后老卤蒸发过程中可获得较高品质的水氯镁石,冷冻脱硫后可以提高Li⁺的富集浓度,但最终仍有一水硫酸锂析出。该老卤25 ℃的蒸发析盐规律与Li⁺,Mg²⁺∥Cl^-,SO₄^2-—H₂O四元体系25 ℃介稳相图基本一致。     

西台吉乃尔盐湖盐田与模拟蒸发过程卤水钾、锂的损失研究

目前，西台吉乃尔盐湖的基本生产工艺路线是卤水经过盐田蒸发进行自然浓缩，然后利用钾盐结晶阶段析出的钾混盐、光卤石及蒸发后期残留的富锂老卤加工生产钾、锂产品，但收率均不高。通过盐田固-液相定点取样观测和模拟蒸发实验的设计，对西台吉乃尔盐湖卤水蒸发过程中钾锂损失的情况进行对比研究。结果表明，卤水中钾在富集达20 g/L时开始析出钾混盐矿，锂则在此过程中不断富集，由0.19 g/L浓缩至2.12 g/L，蒸发实验结果基本符合盐田实际生产情况。根据实验结果估算盐田中不同阶段的钾、锂损失，得出钠盐田中钾损失率约为12.3%，钾盐田中钾总回收率约为84.4%；锂在钠盐阶段损失率约为6.50%，在钾混盐阶段损失率约为11.59%，在光卤石阶段损失率约为6.21%，在老卤阶段损失率约为6.44%，锂在盐田系统中总损失率约为30.74%，其中在钾混盐结晶阶段锂损失量最大。     

二组分液体蒸发模型的理论与实验研究

有毒液体泄漏后的蒸发会导致人员中毒和环境污染,估算有毒液体的蒸发速率对于预测有毒蒸汽在环境中的浓度分布至关重要,尤其是多组分液体,蒸发过程较复杂,蒸发速率的预测大都基于经验模型和半经验模型,且很少考虑热传递对蒸发的影响。文中研究建立了描述二组分液体蒸发质量和液体温度随时间变化的数学模型。设计建造了风洞实验台,并针对不同体积配比下的苯和乙醇混合溶液进行了风洞实验,并将实验测量值同模型计算值进行了比较。结果表明,新建立的模型能够较准确地预测二组分液体蒸发质量和温度随时间的变化,其预测平均偏差分别为25.82%和33.79%,从而为今后研究多组分液体的蒸发过程奠定了基础。     

锯齿板逆流露点间接蒸发冷却器性能研究

提出了一种锯齿板逆流露点间接蒸发冷却器,设计了4种结构模型,主要研究不同进气条件对锯齿型蒸发冷却器性能的影响。结果表明:在研究范围内,相对湿度、进气(环境)温度、进气速度对产气温度和湿球效率有显著的影响;当工作气体湿通道下表面与产气通道下表面同为锯齿面时,冷却效果最好;当进气温度为30℃、进气速度为1m/s、相对湿度为80%时,相比传统结构,冷却效率提升最大,为25. 45%。     

四氧化二氮推进剂贮存条件下蒸发模型研究

模拟贮存环境下四氧化二氮泄漏形成液池的蒸发环境,设计了研究实验.研究了贮存条件下风速、液池面积、温度、湿度等单一因素对四氧化二氮蒸发速率的影响,结果表明随着影响因素值增大,四氧化二氮的蒸发速率也相应增大.建立了预测贮存条件下四氧化二氮蒸发速率模型,为研究四氧化二氮推进剂贮存过程中泄漏事故发生后形成有害气体环境的安全处置...     

硫酸盐型卤水低温处理及其液相 蒸发析盐规律的理论研究

青海省碱北洼地晶间卤水为典型的硫酸盐型卤水,该地区夏季气候干燥炎热,冬季寒冷,为更好地了解该类型盐湖卤水在自然条件下的蒸发过程,以碱北洼地晶间卤水为研究对象,依据Na^+,K⁺,Mg²⁺//Cl^-,SO₄^2－-H₂O （15 ℃）五元介稳体系相图,首先将原始卤水自然蒸发,在氯化钠饱和阶段取4组不同Mg2+值的卤水为冷冻实验样品,分别研究了在-7 ℃、-16 ℃下的冷冻过程。实验结果表明,液相中SO₄^2－、Na⁺以Na₂SO₄·10H₂O的形式析出,改变了液相组成,卤水液相组成点在相图中从软钾镁矾相区移动至氯化钾相区,再将分离后的液相分别蒸发,结果表明,卤水经过冷冻处理之后再蒸发后可以得到较多光卤石矿,对利用该类型卤水生产氯化钾具有重要意义。     

板式蒸发式冷凝器热工性能实验

对影响板式蒸发式冷凝器热工性能的主要因素——空气的湿球温度、冷凝温度、相对湿度做了实验研究。结果显示：冷凝温度和冷凝压力均随着入口空气湿球温度的升高而升高;入口空气相对湿度对压缩机功耗的影响与湿球温度对压缩机功耗的影响均比较大;对基于同一压缩系统的实验比较表明,在冷凝温度为38℃时,板式蒸发式冷凝器的热流密度比管式蒸发式冷凝器平均大30.5%;且在相同的冷凝温度下,入口空气湿球温度越低,板式蒸发式冷凝器的热流密度比管式蒸发式冷凝器大得越多。     

中国盐湖卤水蒸发实验研究进展

中国盐湖众多,盐湖中矿产资源丰富,受盐湖所处地理位置和自然气候条件限制,盐湖开发采取了不同的工艺路线。根据盐湖卤水的水化学类型不同可将盐湖分为3类,即碳酸盐型、硫酸盐型和氯化物型,每种盐湖类型盐湖卤水相图各异,盐类矿物组成也不相同。针对3种类型盐湖,中国盐湖研究人员做了大量的盐湖卤水蒸发实验研究工作,取得了不少科研成果。汇总了前人针对3种类型盐湖卤水所进行的蒸发实验研究成果,分析了各类型卤水蒸发浓缩规律和盐类矿物特征,为相似盐湖卤水蒸发实验研究提供参考。     

江陵凹陷地下卤水75℃等温蒸发析盐规律研究

对江陵凹陷地下卤水进行了75℃等温蒸发实验,以了解卤水在蒸发过程中的化学组成变化,查明卤水的析盐规律和各离子的富集规律,为该卤水的综合利用提供理论依据。实验结果表明,江陵地下卤水在75℃等温蒸发过程中的析盐顺序为:氯化钠→氯化钠+氯化钾→氯化钠+氯化钾+氯化铵→氯化钠+氯化钾+氯化铵+硼酸;微量元素锂、铷、铯、碘和溴高度富集于老卤中,有利于这些元素的提取和综合利用。     

浓海水鼓泡滩晒过程初探

实验搭建了一块120 m²的浅滩鼓泡浓海水晒盐池,盐池中含9120个直径为1 mm的鼓气孔,采用额定流量为420 m³·h^-1的鼓风机鼓泡。测定了鼓泡池及1 m²对照盐池液位、温度、波美度、环境温湿度的变化,分析了气象条件和鼓气量对蒸发量的影响。研究表明,从上午12点至下午3点鼓泡晒盐效果最佳,在最佳条件下比对照池每小时可多蒸发120 kg水蒸气,但通过鼓气直接带走的水蒸气量不足8.7 kg,漂浮的气泡使盐池表面积增加50%~60%,多蒸发约50%的水蒸气,其余的水蒸气通过其他方式蒸发。与传统晒盐方法相比,浅滩鼓泡晒盐具有更快的蒸发速率,若能显著降低鼓泡管路成本和能耗,将具有较好的应用前景。     

Thermodynamic and kinetic behavior of glycerol aerosol

Glycerol and propylene glycol mixtures are common carrier solutions in electronic cigarettes. Aerosols produced from these mixtures will evaporate quickly in a dry environment due to their high volatility. In a humid environment, such as the lungs, the kinetics of evaporation and hygroscopic growth determine the evolution of aerosol plume glycerol. Here, we apply a temperature and relative humidity-controlled hygroscopicity/volatility tandem differential mobility analyzer system to study the growth and evaporation kinetics of glycerol aerosol over a wide range of temperature, relative humidity, and residence times. Results show that at dry conditions glycerol aerosols evaporate within seconds at temperatures warmer than 20°C and that the accommodation coefficient of glycerol vapor on dry glycerol particles is 0.8. Under humidified conditions, the mutual depression of vapor pressures of the aqueous glycerol/water solution slows the glycerol evaporation rate consistent with thermodynamic and kinetic model predictions. Model calculations show that water vapor aided condensation of glycerol can occur at high relative humidity for glycerol vapor concentrations that result in glycerol particle evaporation under dry conditions. The combined results will help with constraining computational modules that model the evolution of glycerol-containing aerosols along a prescribed thermodynamic trajectory.

Copyright © 2016 American Association for Aerosol Research     

A model for the relative humidity effect on the readings of the PM10 beta-gauge monitor

In the previous paper (Atmos. Environ. 15 (1981) 1087), we found that the PM₁₀ concentrations detected by the Wedding beta-gauge PM₁₀ monitor and those measured by the manual hi-vol PM₁₀ sampler were quite close when the ambient relative humidity (RH) was lower than the deliquescence RH (DRH) of aerosols. However, when the deliquescent point was exceeded, PM₁₀ concentrations of the beta-gauge were found to be higher and differences increased with an increasing ambient RH. In addition, theoretical water mass calculated by a thermodynamic model (ISORROPIA model, (Aquat. Geochem. 4 (1998) 123)) was found to be much higher than the actual values. In this study, models were developed to determine water evaporation loss from collected particles on the filter tape of the beta-gauge during sampling and in the monitoring room. Simulated results show that all absorbed water will evaporate completely at RH lower than about 85%. However, absorbed water does not evaporate completely at RH higher than about 85%, and remaining water in particles accounts for higher beta-gauge readings than the hi-vol concentrations. The simulated daily beta-gauge PM₁₀ concentrations are close to the actual beta-gauge readings obtained previously.     

Influence of drum inlet air conditions on drying process in a domestic tumble dryer

This study examines how the inlet air temperature, relative humidity, and flow rate influence the textile drying process in an open cycle tumble dryer. An experimental setup was prepared by connecting a domestic tumble dryer to an external system for controlled heating, humidification, and transport of air. Experiments were conducted by drying cotton textiles (8?kg dry mass) at different air inlet conditions. On the basis of measured data, correlations for determination of the total drying time, the moisture evaporation rate during the constant drying rate, and the area-mass transfer coefficient were developed. The process in the drum was modeled by using an established moisture evaporation model, based on sorption isotherms. A commonly used and a recently reported sorption isotherm for cotton were used with the model. Agreement between calculated and measured drying curves was better in case of the commonly used sorption isotherm, but final moisture content was better predicted by the recently reported sorption isotherm.     

The Effect of Water Evaporation on Photoacoustic Signals in Transition and Molecular Flow

Evaporation of water changes the response of photoacoustic instruments to light-absorbing particles. Previous calculations of this effect are valid for particles much larger than the mean free path of air. These calculations are extended here to include transition and molecular flow as well as various mass accommodation coefficients for water. For commonly encountered conditions, evaporation can significantly reduce the photoacoustic signal if the mass accommodation coefficient of water on aerosol particles is larger than about 0.01. Unlike the growth of cloud droplets, the photoacoustic signal is very sensitive to changes in the accommodation coefficient between 0.1 and 1. This may provide a way to measure large accommodation coefficients. For a given accommodation coefficient, the change in the photoacoustic signal depends more on absolute than relative humidity. To minimize the effects of evaporation it is better to remove water from the air rather than reduce relative humidity with heating.     

循环转轮空调系统变工况除湿特性

转轮除湿空调系统可回收船舶余热将其作为转轮再生热源并改善舱室内空气品质，有望实现低能耗高效除湿。为此，建立了一种新型循环转轮除湿空调系统，定量研究了变工况条件下系统的除湿特性，获得了不同循环分流系数（45%～85%）、处理空气温度（28～40℃）、处理空气相对湿度（50%～85%）、再生空气温度（130～160℃）对系统除湿效果的影响。结果表明：所提出的转轮除湿空调系统相比常规海水直接冷凝除湿方式可有效提高除湿率；在相同循环分流系数下，系统的除湿率随着处理空气温湿度以及再生空气温度的升高而逐渐增大；系统的除湿率存在最优值，其对应的最佳循环分流系数为50%～75%，该系数随着处理空气温湿度的增大而减小，随着再生空气温度的升高而增大。     

蒸发式过冷水制冰中单个水滴的蒸发过冷特性

为分析蒸发式过冷水制冰中单个水滴在此低温低湿空气环境中的蒸发特性,建立了水滴蒸发过冷过程的数理模型。通过悬挂水滴实验与模拟结果的对比,验证了模型的有效性。因此利用该数学模型预测微小直径水滴的蒸发特性是可行的。通过模拟计算获得了水滴初始直径、初始水温、空气温度、空气含湿量和空气流速对水滴蒸发过冷过程的影响。结果表明,水滴初始直径越小、温度越低或空气流速越大,水滴的冷却速率就越大,达到稳态时的过冷时间就越短。另外,通过降低空气温度或含湿量不仅提高了水滴的冷却速率,而且增加了水滴达到稳态时的过冷度。通过水滴蒸发过冷特性的分析,可为制冰系统的优化设计及提高系统制冰效率提供理论参考。     

基于非平衡态成盐相图实现苦卤资源高效利用(英文)

Salt-forming regions for a complex salt-water system in non-equilibrium state of evaporation process are usually different from those in solubility diagrams.To understand the solid-forming region of NaCl and improve the utilization of bittern resources,experiments were carried out to evaporate 20 representative mixture solution samples of Na +,Mg 2+ //Cl-,2 4 SO-H2O system with an average evaporation intensity of(1.4±0.4) g·L-1 ·min-1(water) at boiling temperature 348 K,and determine the NaCl solid-forming regions in non-equilibrium state.Because of the complexity of salt-forming region,a maximal region and a minimal region were proposed to express the non-equilibrium state salt-forming region with different crystal seed,and a conditional salt-forming region was proposed to present the characteristic region of non-equilibrium salt-forming phase diagram.The areas of the maximal and minimal regions are 2.00 and 1.56 times those in solubility diagram,so it is possible to utilize bittern resources in high efficiency.The recovery rates of NaCl were 99.65%,93.14%,88.57%,72.76%,and 83.68%for six typical bittern sources from Tulantai Salt Lake(China),Dongtai Salt Lake(China) ,Jilantai Salt Lake(China),Qarun Salt Lake(Egypt) and seawater,respectively.It is testified that the non-equilibrium state salt-forming phase diagram can be used in industrial processes.     

蒸汽冷凝水的回收

使用卤水电解制烧碱,将蒸发碱蒸汽回收到高位槽后再利用,减少了废水排放量,缓解了环保压力。     

Hygroscopic equilibrium of cottonseed

Summary and Conclusion An investigation has been made of the hygroscopic equilibrium of cottonseed over a range of 31% to 93% relative humidity. From 31% to 71% relative humidity the moisture content of cottonseed increased linearly from 6.03% to 10.27%. From 71% to 93% relative humidity the moisture content increased rapidly from 10.27% to 22.19%. When cottonseed was separated into meats and hulls, including linters, it was found that the hulls contained more moisture than the meats. On the basis of these results it is apparent that, when stored cottonseed is aerated, consideration should be given to the effect of local atmospheric conditions. The relative humidity of the air used for aeration can affect the moisture content of the stored seed either favorably or adversely. Although it may temporarily reduce heating by conduction of the heat of respiration, it may increase the moisture content and thus stimulate further respiration and heating. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.