Chemical dehydration coupling multi-effect evaporation to treat waste sulfuric acid in titanium dioxide production process

In order to concentrate the diluted sulfuric acid from the titanium dioxide(TiO2)production of sulphate process,a new concentration process was proposed by coupling chemical dehydration and multi-effect evaporation.The ferrous sulfate monohydrate(FeSO4·H2O),as the dehydrant,was added to the diluted sulfuric acid to form ferrous sulfate heptahydrate(FeSO4·7H2O)according to the H2SO4-FeSO4-H2O phase diagrams,which partially removes the water.This process was named as Chemical Dehydration Process.The residual water was further removed by two-effect evaporation and finally 70 wt%sulfuric acid was obtained.The FeSO4·H2O can be regenerated through drying and dehydration of FeSO4·7H2O.The results show that FeSO4·H2O is the most suitable dehydrant,the optimal reaction time of chemical dehydration process is 30 min,and low temperature is favorable for the dehydration reaction.45.17%of the entire removed water can be removed by chemical dehydration from the diluted sulfuric acid.This chemical dehydration process is also energy efficient with 24.76%saving compared with the direct evaporation process.Furthermore,51.21%of the FeSO4 dissolved originally in the diluted sulfuric acid are precipitated out during the chemical dehydration,which greatly reduces the solid precipitation and effectively alleviates the scaling in the subsequent multi-effect evaporation process.

Separation of Lactic Acid from Diluted Solution by Hybrid Short Path Evaporation and Reactive Distillation

This work describes the separation and purification of lactic acid from diluted solution by HSPE （hybrid short path evaporation） and RD （reactive distillation） as coupled process. The results showed that it is possible to increase lactic acid concentration up to 4.7 times higher than the raw material concentration.

Case Studies of Heat Integration of Evaporation Systems

In this paper, through two case studies, evaporation systems are considered in the context of overall process, and then are optimized to obtain energy-saving effect. The possible evaporation schemes are given when integrated with the background process and how to optimize the evaporator is shown. From the case studies, it can be seen that sometimes incomplete integration and heat pump evaporation are better than complete integration so should be considered as candidate retrofit schemes.

Hybrid hydrovoltaic electricity generation driven by water evaporation

Water evaporation is a ubiquitous natural process exploiting thermal energy from ambient environment.Hydrovoltaic technologies emerged in recent years offer one prospective route to generate electricity from water evaporation,which has long been overlooked.Herein,we developed a hybrid hydrovoltaic generator driven by natural water evaporation,integrating an“evaporation motor”with an evaporation-electricity device and a droplet-electricity device.A rotary motion of the“evaporation motor”relies on phase change of ethanol driven by water-evaporation induced temperature gradient.This motion enables the evaporation-electricity device to work under a beneficial water-film operation mode to produce output of~4 V and~0.2μA,as well as propels the droplet-electricity device to convert mechanical energy into pulsed output of~100 V and~0.2 mA.As different types of hydrovoltaic devices require distinctive stimuli,it was challenging to make them work simultaneously,especially under one single driving force.We here for the first time empower two types of hydrovoltaic devices solely by omnipresent water evaporation.Therefore,this work presents a new pathway to exploiting water evaporation-associated ambient thermal energy and provides insights on developing hybrid hydrovoltaic generators.

On the Development of a Hybridized Ant Colony Optimization (HACO) Algorithm

This paper proposes a Hybridized Ant Colony Optimization (HACO) algorithm. It integrates the advantages of Ant System (AS) and Ant Colony System (ACS) of solving optimization problems. The main focus and core of the HACO algorithm are based on annexing the strengths of the AS, ACO and the Max-Min Ant System (MMAS) previously proposed by various researchers at one time or the order. In this paper, the HACO algorithm for solving optimization problems employs new Transition Probability relations with a Jump transition probability relation which indicates the point or path at which the desired optimum value has been met. Also, it brings to play a new pheromone updating rule and introduces the pheromone evaporation residue that calculates the amount of pheromone left after updating which serves as a guide to the successive ant traversing the path and diverse local search approaches. Regarding the computational efficiency of the HACO algorithm, we observe that the HACO algorithm can find very good solutions in a short time, as the algorithm has been tested on a number of combinatorial optimization problems and results shown to compare favourably with analytical results. This strength can be combined with other metaheuristic approaches in the future work to solve complex combinatorial optimization problems.

干湿联合式蒸发空冷器管束腐蚀失效分析及预防措施

干湿联合式蒸发空冷器的传热管束包含预冷管束和蒸发管束,预冷管束采用翅片管,蒸发管束采用蛇形光管。该类型设备在某沿海石化企业使用过程中,蛇形光管U形弯部位出现不同程度的腐蚀穿孔泄漏,为了确定腐蚀泄漏原因,以石脑油加氢装置中石脑油分馏塔顶空冷器为例,采用多种试验手段对腐蚀失效原理进行分析。根据外观检查、水质分析、化学成分检测、力学性能及金相检测、腐蚀形貌观察和产物成分分析等分析结果判断,该空冷器的主要失效原因是浓差腐蚀及电化学腐蚀共同作用的结果,并对此提出了相应的预防措施。

基于GRO优化的VMD-HKELM月蒸发量预测方法研究

水面蒸发预测对于水库水量预测、区域水量平衡分析和水资源量核算等具有重要意义。水面蒸发量预测影响因素众多,并最终体现在随时间变化的蒸发量监测数据中。为此,基于淘金热(GRO)算法优化变分模态分解(VMD)-混合核极限学习机(HKELM)提出两种方案。方案Ⅰ先对月蒸发量时间序列分解,后划分训练集、测试集;方案Ⅱ先对月蒸发量划分训练集、测试集,再进行时间序列分解。通过一种新型元启发式算法对分解技术VMD、预测器HKELM超参数进行目标寻优并建立多种模型,采用云南省龙潭寨、西洋街水文站月蒸发量预测实例对方案Ⅰ、方案Ⅱ各模型进行检验。结果表明:方案Ⅰ各模型性能优于方案Ⅱ,各模型的拟合精度和预测精度总体上随分解分量数的增加而提高,但方案Ⅰ使用了测试集信息,导致预测精度虚高;方案Ⅱ各模型具有较好的预测精度和稳健性能,其用于月蒸发量时间序列预测是可行的,反映出客观真实的预测效果,具有较好的实用价值和意义。

基于混合模型的脱硫废水旁路蒸发系统能耗特性

脱硫废水旁路蒸发系统抽取部分空预器入口热烟气会使锅炉效率降低、煤耗增加。为了实现对抽取热烟气造成能耗增加的精准预测,提出了一种机理模型与人工神经网络有机结合的混合模型预测方法。采集广东某660MW电厂的运行数据作为样本,以空气预热器进口的风温、空气的流量、抽取烟气量、抽取烟气温度、锅炉负荷以及给煤量6个参数作为输入,建立了用于预测经过空气预热器空气换热量的BP神经网络模型,对不同隐含层结构进行模拟计算,分析比较确定了网络的最优结构是6-9-1,最终模型的决定系数R^(2)是0.99478,预测模型的相对误差在1%附近波动,整体预测效果较好。在此基础上结合机理模型,针对机组负荷波动及抽取烟气量波动的典型工况进行了能耗预测,获得了旁路蒸发系统能耗的定性规律。

A water-evaporation-induced self-charging hybrid power unit for application in the Internet of Things

A self-charging hybrid power unit has been developed by integrating a water-evaporation-induced nano- generator with a flexible nano-patterned supercapacitor. The nanogenerator can harvest environmental thermal energy and mechanical energy through the water evaporation process, and the supercapacitor can be charged simultaneously. The former offers stable electrical power as output, whereas the Ppy- based supercapacitor shows a capacitance of 12.497 m F/cm^2 with 96.42% retention after 4,000 cycles. After filling the power unit with water as the fuel, it can be fully charged in about 20 min. The power unit can be flexibly integrated with electronic devices such as sensor nodes and wireless transmitters employ- ing the Internet of Things. This new approach can offer new possibilities in continuous future operation of randomly distributed electronic devices incorporated in the Internet of Things.

In situ Reduction of Silver Nanoparticles on Chitosan Hybrid Copper Phosphate Nanoflowers for Highly Efficient Plasmonic Solar-driven Interfacial Water Evaporation

The development of water purification device using solar energy has received tremendous attention.Despite extensive progress,traditional photothermal conversion usually has a high cost and high environmental impact.To overcome this problem,we develop a low cost,durable and environmentally friendly solar evaporator.This bilayered evaporator is constructed with a thermal insulating polyvinylidene fluoride(PVDF)membrane as a bottom supporting layer and plasmonic silver nanoparticles decorated miero-sized hybrid flower(Ag/MF)as a top light-to-heat conversion layer.Compared with the sample with a flat silver film,the two-tier Ag/MF has a plasmonic enrichment property and high efficiency in converting the solar light to hcat as cach flower can gencrate a microscale hotspot by enriching the absorbed solar light.On the other hand,the PVDF membrane on the bottom with porous structure not only improves the mechanicalstability of the entire structure,but also maintains a stable water supply from the bulk water to the evaporation interface by capillarity and minimizes the thermal conduction.The combination of excellent water evaporation ability simple operation,and low cost of the production process imparts this type of plasmonic enhanced solar-driven interfacial water evaporator with promising prospects for potable water purification for point-of-use applications.

Multifunction Zno/carbon hybrid nanofiber mats for organic dyes treatment via photocatalysis with enhanced solar-driven evaporation

ZnO-based photocatalytic materials have received widespread attention due to their usefulness than other photocatalytic materials in organic dye wastewater treatment.However,its photocatalytic efficiency and surface stability limit further applicability.This paper uses a one-step carbonization method to prepare multifunctional ZnO/carbon hybrid nanofiber mats.The carbonization creates aπ-conjugated carbonaceous structure of the mats,which prolongs the electron recovery time of ZnO nanoparticles to yield improved photocatalytic efficiency.Further,the carbonization reduces the fiber diameter of the carbon hybrid nanofiber mats,which quadruples the specific surface area to yield enhanced adsorption and photocatalytic performance.At the same time,the prepared nanofiber mats can increase the evaporation rate of water under solar irradiation to a level of 1.46 kg·m^(-2)·h^(-1)with an efficiency of 91.9%.Thus,the nanofiber mats allow the facile incorporation of photocatalysts to clean contaminated water through adsorption,photodegradation,and interfacial heat-assisted distillation mechanisms.

太阳能-土壤复合式地源热泵供暖的实验研究

在所建立的太阳能-土壤复合式地源热泵实验台上,进行了单眼埋管井取热土壤源热泵供暖(模拟埋管面积不够的情形)和复合式地源热泵供暖的实验研究。结果表明,热泵机组从单眼埋管井取热时,冷凝器出水温度只有35℃左右,并且机组运行一段时间后,蒸发器出现结冰现象,造成了压缩机连续启停的不稳定工况;复合式系统运行时,蒸发压力始终保持在较高的水平,冷凝器出水温度达到43℃左右,可以满足风机盘管冬季工况的要求,复合式系统的机组平均制热性能系数为3.7。

气象要素对杂交中籼稻年度间产量波动的影响

以1990～2004年湖北省中稻区域试验及武汉、荆州、襄樊气象站的资料为依据,分析各种气象要素对杂交中籼稻年度间产量波动的影响。结果表明,①各种气象要素对水稻产量波动都有不同程度的影响,其影响力依次为7～9月份累计蒸发量、8～9月份的日平均相对湿度和7～9月份累计日照时数;②7～9月份累计蒸发量与水稻产量间的相关系数为0.799 7,达极显著水平;③7～9月份的累计蒸发量x5对产量y有最大的直接正效应(x5→x5→y=1.358 6)。

双源蒸散发模型估算潜在蒸散发量的对比

潜在蒸散发取决于气候条件与下垫面植被覆盖状况,是农田及流域水循环研究的重要内容。该文针对现有的3种估算潜在蒸散发的双源模型(层状模型、块状模型、混合型模型),设定不同的下垫面植被覆盖状况,较为详细地比较了3种模型在不同植被覆盖条件下的潜在蒸散发估算能力,并对其区分土壤表面潜在蒸发与植被冠层潜在蒸腾的合理性进行了评价。结果表明,混合双源模型较层状模型和块状模型具有更好的模拟效果,能够适用于更广的下垫面植被覆盖状况。

转轮除湿复合式空调系统

介绍了转轮除湿与常规冷却及蒸发冷却相结合的两类复合式空调系统。指出在要求低湿或湿负荷较大的场合，采用前者既可避免制冷机的蒸发温度过低影响制冷效率，又可避免凝结水排放不当造成渗漏等问题，利于节能；采用后者，节能效果更显著，而且既无ＣＦＣ问题，又能缓解夏季电力供应紧张的压力。

串联型复合式冷却塔数学模型及试验验证

构造串联型干湿结合复合式冷却塔的数学模型,利用Matlab软件进行模拟计算,搭建试验台进行试验研究.结果显示:随着截面风速增加,冷却水进出口温差逐渐增大,而出口空气温度基本不变,焓值减小,喷淋水量对冷却水进出口温差有显著影响,但对出口空气温度和焓值影响较小.模拟计算结果与试验测试值的最大相对误差不超过12%,说明该数学模型精度满足工程计算要求.利用该数学模型计算并分析了喷淋水量为2.1m^3/h和截面风速为3.0m/s时各参数随冷却塔高度的分布情况,结果显示:空气焓值随冷却塔高度增加而增加;空气温度在蒸发冷却段基本不变而在翅片管段显著增加,冷却水在翅片管段温降占总温降的36%左右;喷淋水流经填料层后温度降低,而在光管蒸发冷却段呈现先升温后降温现象.

基于ARIMA-SVM模型的翅片管蒸发器结霜性能预测

针对翅片管蒸发器结霜过程混杂着复杂的线性和非线性特征且测试数据受噪声干扰大,使用单一的模型无法对其性能进行预测的难题,建立了基于求和自回归移动平均(Autoregressive Integrated Moving Average,ARIMA)和支持向量机(Support Vector Machine,SVM)的翅片管蒸发器结霜性能组合预测模型.利用实验数据对模型进行了验证和评估,并与单一ARIMA模型和SVM模型做了对比分析.结果表明,基于ARIMA-SVM的组合预测模型能兼顾结霜过程的线性和非线性特征,具有良好的预测性能,并能够较精确地预测到翅片管蒸发器性能参数的转向点.

光-煤互补复合发电系统综合性能分析

将扩容蒸发式槽式太阳能蒸汽发生系统与600 MW燃煤机组联合,构建了光-煤互补复合发电系统,建立了其变工况计算模型及技术经济评价模型,从太阳能侧、汽轮机侧及复合发电系统3方面进行了热力性能分析及技术经济性评估。结果表明,光-煤互补复合发电系统具有显著的节能减排效果,系统产生的太阳能蒸汽取代汽轮机第1段抽汽时效果最为明显,太阳能侧各指标随取代抽汽段数增大呈阶段性下降趋势,太阳能到电能的转换效率最高为23.5%;各集成模式下的单值发电成本相差不大,平均为0.19元/(kW·h);从净现值判断取代第1段抽汽是较好的选择,从净现值率、盈利能力判断取代第2段抽汽是较好的选择。

插电式混合动力车燃油蒸发控制系统开发

对插电式混合动力车面临的燃油蒸发排放超标问题进行了探讨,通过鱼骨刺法识别出HC排放超标的影响因素,提出了两种燃油蒸发排放控制方案,既高压燃油箱方案及燃油冷却方案,并详细介绍了两种方案的系统结构以及控制逻辑。

钙钛矿薄膜的气相法制备及光伏应用的研究进展

近几年,有机-无机杂化钙钛矿太阳电池迅速兴起并且获得了媲美硅基电池的效率,受到了学术界以及产业界的高度关注。随着效率的提高,如何解决稳定性、大面积制备等问题也迅速被提上日程。汽相薄膜制备方法是目前广泛应用于制备大面积致密半导体薄膜及器件的一种工业技术。自2013年Snaith团队成功实现钙钛矿薄膜的真空汽相沉积以来,汽相制备技术在钙钛矿薄膜及器件制备领域也获得越来越多的研究。本论文将对气相法制备钙钛矿薄膜和器件的研究进行综述。重点介绍气相法制备方法的发展及汽相制备方法中一些共有的物理问题,包括MAI分子蒸发的弥散性问题;真空度对分子扩散及薄膜形态的影响以及温度对固态反应的影响。最后将简单讨论进一步提高材料和器件特性可以采取的方案。