Coupling of a Liquid Organic Hydrogen Carrier System with Industrial Heat

Energy storage is needed for adjusting fluctuating renewable energies to the actual energy demand. A liquid organic hydrogen carrier (LOHC) system is examined for its suitability as a storage system for industrial applications. Integration of the LOHC system, e.g., into a cement plant allows for optimized utilization of waste heat. The exhaust heat from the cement plant can increase the efficiency of the storage system. The effectiveness of the LOHC system can be elevated by twelve percentage points. The working electricity costs of the cement plant can be significantly reduced by adding a LOHC storage system.     

逆电渗析法热-电转换系统循环工质匹配准则

将开式逆向电渗析法浓差能发电技术原理与吸收式制冷/热泵系统循环原理相结合,提出了一种全新的闭式热-电循环转换方法,且发现工作介质（溶质与溶剂混合物）是影响该系统能量转换效率的关键因素之一。以9种溶质（一价无机盐）和17种溶剂（标准沸点温度在40~150℃）为研究对象,通过分析工质的13项关键物性参数（沸点温度、汽化潜热、比热容、溶解度、偏心因子、偶极矩、相对介电常数、电导率、黏度、热导率、燃爆极限、自动点火温度及毒性）,建立了从热力学性质、电化学性质、输运特性、危险性等多角度来综合评价热-电循环转换系统工质匹配性的准则,并据此推断无机盐-溶解剂-调节剂三元混合物极具发展潜力。     

热能储存材料研究进展

热能储存材料用于储热或储冷，节能效果显著。文中综述了热能储存材料研究的新进展，介绍了热能储存材料的分类、性能及新型储热、储冷材料。     

新型相变材料换热器热能储存与释放特性

研究了一种新型相变材料换热器,在其进出口的相应温度测试点布置铜镍合金热电偶,然后分别以不同的流速通入温度各为40℃、16—17℃的热、冷空气流,利用温度测试系统连续测出各测点的温度值。理论分析和实验研究结果验证了该换热器具有良好的热能储存与释放特性:当气流的质量流速分别为0.132,0.096 kg/s时,若相变材料的平均初始温度为17.4,17.7℃时,经过910,1 030 min后该换热器热能储存量各为21 056.67,21 014.34 kJ;在放热过程中,该换热器出口的气流温度维持在20℃以上的时间各为594,717 m in。它可用于温室、暖房、空调或工业生产中各种低温热能的回收和利用。     

混合工质回热朗肯循环回收天然气冷量的模拟

高压天然气在集输过程中常需要节流,节流后的低温天然气具有品位低但是总量大的冷能.采用朗肯动力循环利用冷能发电是一种可行的思路.但由于天然气释放的冷能品位低且是一个变温过程,因而循环效率一般很低.由于混合工质的相变是一个变温过程,因而采用混合工质的朗肯循环,可以较好地加热与冷却曲线接近,从而减少不可逆损失.同时利用回热过...     

一种有效的潜热储能球床放热性能的数值分析方法

针对潜热储能床的数值计算,研究了现有多孔介质模型应用于该问题模拟时的不足, 提出利用等效显热容处理相变问题的方法,并将其应用于潜热储能床放能过程的数值模拟中,这样使模型得到极大简化,并且较其他模型能更全面地反映储能床中的相变换热与换热流体流动的信息。将数值计算的结果与实验数据进行了对比,两者吻合很好。同时,通过对储能床中的温度分布及换热流体的流场分析, 探讨了影响潜热储能床放热特性的因素。     

Increment of specific heat capacity of solar salt with SiO2 nanoparticles

Thermal energy storage (TES) is extremely important in concentrated solar power (CSP) plants since it represents the main difference and advantage of CSP plants with respect to other renewable energy sources such as wind, photovoltaic, etc. CSP represents a low-carbon emission renewable source of energy, and TES allows CSP plants to have energy availability and dispatchability using available industrial technologies. Molten salts are used in CSP plants as a TES material because of their high operational temperature and stability of up to 500°C. Their main drawbacks are their relative poor thermal properties and energy storage density. A simple cost-effective way to improve thermal properties of fluids is to dope them with nanoparticles, thus obtaining the so-called salt-based nanofluids. In this work, solar salt used in CSP plants (60% NaNO₃ + 40% KNO₃) was doped with silica nanoparticles at different solid mass concentrations (from 0.5% to 2%). Specific heat was measured by means of differential scanning calorimetry (DSC). A maximum increase of 25.03% was found at an optimal concentration of 1 wt.% of nanoparticles. The size distribution of nanoparticle clusters present in the salt at each concentration was evaluated by means of scanning electron microscopy (SEM) and image processing, as well as by means of dynamic light scattering (DLS). The cluster size and the specific surface available depended on the solid content, and a relationship between the specific heat increment and the available particle surface area was obtained. It was proved that the mechanism involved in the specific heat increment is based on a surface phenomenon. Stability of samples was tested for several thermal cycles and thermogravimetric analysis at high temperature was carried out, the samples being stable.

PACS

65.: Thermal properties of condensed matter; 65.20.-w: Thermal properties of liquids; 65.20.Jk: Studies of thermodynamic properties of specific liquids     

热集成变压精馏分离乙醇-乙腈混合物

以乙醇-乙腈混合物为对象,研究了该体系在实验压力范围内的共沸组成,分析了采用变压精馏工艺分离精制乙醇和乙腈的可行性。通过比较实验压力范围内（101~500 kPa）体系的共沸组成与Aspen Plus模拟软件中计算的体系共沸组成,选择了适合的物性方法。在实验装置上进行了变压精馏法分离精制乙醇、乙腈混合物的实验,重点考察了不同回流比对分离效果的影响,得到了质量分数大于99.5%的乙醇和乙腈产品。 应用Aspen Plus模拟软件对乙醇-乙腈体系的热集成变压精馏过程进行了模拟计算,对比了热集成变压精馏与传统变压精馏的能耗,发现热集成变压精馏节能达35%。     

表面自由能差对乙醇-水混合蒸气冷凝传热特征的影响

实验研究了常压下不同浓度的乙醇-水混合蒸气的冷凝传热过程.发现在不同的乙醇含量和过冷度条件下,冷凝形态呈现膜状、过渡态和滴状的变化.相应传热系数也发生变化.基于该冷凝过程实质为薄液膜表面上的冷凝过程,以及蒸气冷凝传热系数随表面自由能差渐进变化的机理,首先确定了其表面自由能差为液-液表面自由能差,并以此解释了乙醇-水混合蒸气冷凝过程传热特性的变化规律.研究表明,随着冷凝液与薄液膜二者的表面自由能差的增大,冷凝传热系数逐渐增大,并且冷凝形态发生变化,当表面自由能差小于(14±1)mJ·m-2时为膜状冷凝,大于(21±1)mJ·m-2时为滴状冷凝,介于二者之间时为过渡状态.     

Design of mixed energy‐integrated batch process networks by Pseudo‐direct approach

In this article, a novel framework for the design of mixed (combined direct and indirect) integration for batch process systems is presented. The framework is based on the concept of pseudo‐direct energy integration (PDEI) which reformulates indirect integration as direct integration using pseudo‐process streams. Two algorithms are presented to achieve energy integration for batch processes operating cyclically (in a campaign mode). The first algorithm targets maximization of energy recovery and overcomes the limitations of some of the existing contributions for design of mixed integrated systems. The second algorithm provides a network reduction methodology to generate a cadre of integrated designs while exploring the trade‐off between capital (number of heat exchangers and storage units) and operating costs (utility consumption). The proposed framework is illustrated using a benchmark example of two hot and two cold streams. © 2017 American Institute of Chemical Engineers AIChE J, 63: 55–67, 2018     

First experimental results of a new hybrid solar/gas multi-effect distillation system: the AQUASOL project

From 2002 to 2006, a combined R&D project named AQUASOL has been carried out at the facilities of the Plataforma Solar de Almería (Spain). Main objective of this project has been the development of a hybrid solargas desalination system based on multi-effect distillation process that meets at the same time the requirements of low-cost, high efficiency and zero discharge.

The final AQUASOL plant, implemented at the Plataforma Solar de Almería for its evaluation under real meteorological conditions, is composed of: (i) a 14-cell forward-feed vertically-stacked MED unit, (ii) a 500m2 stationary CPC (compound parabolic concentrator) solar collector field, (iii) a 24 m3 thermal storage system based on water, (iv) a new advanced prototype of double-effect absorption (LiBr-H2O) heat pump, (v) a smoketube gas boiler to guarantee 24-h operation

This paper shows the first experimental results obtained during the test campaign of the project. The performance ratio reached by the distillation plant in different operational modes is evaluated, as well as the issues related with the operation of the subsystems that compose the AQUASOL desalination system.     

循环冷却水系统的复合节电方式实践

以并联水泵供水的循环冷却水系统为节电对象,分步实施了水泵叶轮切削,单台水泵变频调速的组合控制方案,优化了水泵的工作点,实现了自动调节的恒压供水,完全消除了泵后闸阀的节流损失,总体节电率达46.8%。     

K-401低温热利用项目分析

文章简要介绍了热泵的工作原理,以及类型。并以华北石化公司低温热利用项目K-401为例,通过对项目试运行结果的分析,阐述了热泵机组目前存在的的问题,并提出了相关的改进措施。     

Cu含量对高温相变材料Al-Cu合金热特性的影响

高温相变材料Al-Cu合金是蓄热性能最好的太阳能储存材料之一,而Cu含量对其热特性影响的相关研究未见报道。采用差示扫描量热法（DSC）和激光脉冲法（LFA）研究了Cu含量在7.4%~51.7%范围内的Al-Cu合金相变材料的相变温度、相变潜热、比热容、热扩散系数和热导率,并结合其金相组织对热力学性能变化规律的内在机理进行了分析。结果显示,当Cu含量在7.4%~51.7%范围内时,Al-Cu合金的相变温度在524.4~645.9℃范围内;随Cu含量的增加,Al-Cu合金的质量潜热呈递减趋势,而体积潜热却呈上升趋势。Al-7.4% Cu在熔化和凝固过程具有最大的质量潜热,分别为339.6、343.5 kJ·kg^-1。Al-51.7% Cu在熔化和凝固过程具有最大的体积潜热,分别为1179、1143 MJ·m^-3。当Cu含量在7.4%~51.7%范围内时,Al-Cu合金的比热容随Cu含量的增加呈递减趋势;当温度在25~500℃范围内时,Al-Cu合金的比热容随温度升高呈递增趋势。Al-7.4% Cu的比热容在25℃时为0.85 J·g^-1·K^-1,在500℃时达到最高值1.08 J·g^-1·K^-1。此外,Al-Cu合金的热导率随Cu含量的升高而降低,但即使Cu含量达到51.7%,其常温下的热导率仍然高达104 W·m^-1·K^-1。综合研究结果表明,Al-Cu合金作为高温相变材料具有在太阳能蓄热领域中应用的巨大潜力。     

DSC法测定醋酸-水溶液的比热

利用差示扫描热量计(DSC)测定了醋酸水溶液在温度范围为293.15~359.15K和整个组成范围下的比热,并把比热的测量值与文献值进行了比较, 实验的测量误差小于±2%, 测得的醋酸-水的比热数据完全能满足工程设计的需要。同时把醋酸-水的比热与组成与温度进行了关联,并利用最小二乘法回归出所提方程中的参数,最后导出了一个计算Cp的多项式方程,此方程中既包含温度又包含组成,因此利用此方程可以计算醋酸-水体系在测定温度和组成下的Cp。把用该方程的计算值与实验值进行了比较,117个数据点的总绝对平均相对误差为0.54%。所提方程可应用于对苯二甲酸生产中换热器的设计及相关体系热量平衡的计算,具有实用意义。     

太阳能热泵供暖技术综述

回顾了国内外太阳能热泵的发展过程,介绍了太阳能热泵地板辐射采暖系统主要设备太阳能集热器、蓄热设备、地板采暖系统、控制系统、运行方式的组成和结构形式,论述了太阳能热泵的技术原理和特点以及在供暖方面的应用等。针对当前太阳能热泵供暖系统有待解决的问题进行了分析和探讨,结果表明把热泵技术与太阳能热利用技术结合可提高太阳能集热器效率和热泵系统性能,同时能解决全天候供热问题。     

移动蓄热技术的研究进展

移动蓄热技术是缓解能量供求双方在时间、强度及地点上不匹配的有效方式,是合理利用能源及减轻环境污染的有效途径。本文概述了移动蓄热技术的在工业余热回收利用中的研究进展,分析了我国分散式热用户市场,讨论了化学能储热、显热储热、相变潜热储热技术在移动蓄热车应用中的优缺点,其中潜热储热具有储能密度高、体积小、能量供应稳定等特点,在移动蓄热车中有着广阔的应用前景。在此基础上,归纳了应用于不同热源温度的相变材料,并针对其低导热系数问题,总结了几种强化换热技术。指出了移动蓄热技术的发展方向,展望了移动蓄热技术的市场化应用前景。     

太阳能热化学储能研究进展

太阳能热发电技术对缓解全球资源紧张和改善环境有广阔的应用前景,大规模高温无损储热是太阳能热发电系统的关键。本文通过对显热储能、潜热储能和热化学储能3种热能储存方式的比较,认为热化学储能方法由于储能密度高,且可长期在环境温度下无热损储存,因而为太阳能热发电中的高温热能储存提供了一种潜在的方法。并对热化学储能在太阳能热力发电的应用上进行了技术经济分析,综述了几种有前景的热化学储能体系的研究进展,总结了各种储能体系的现存问题。根据热化学储能方法在实用化过程中存在的技术经济问题,指出了热化学储能技术的未来研究方向是储能反应器的设计、能量储存/释放循环性能探究、储能体系的选择及热化学储能系统的中试放大研究等。     

节能技术在乙烯存储系统中的比较和应用

乙烯是石油化学工业中最重要的基础有机原料之一。通常乙烯采用低温常压存储,因此存储的能耗对乙烯储运的运行成本影响较大。本文通过对低温乙烯存储系统中不同的工艺能耗进行了分析和比较,发现节能技术的应用能回收乙烯冷量,有效的降低乙烯存储的能耗,为低温乙烯存储系统中的节能技术的应用提供参考。     

膏状相变贮能保温隔热弹性腻子的研制

以弹性乳液为成膜物,以陶瓷空心微珠、定形相变材料、重钙和滑石粉为填料,在助剂和水的配合下制成膏状相变贮能保温隔热弹性腻子,除具有良好的黏结强度、弹性、耐水性、抗渗透性和透气性外,还具有相变贮能调温、控温及保温隔热功能,与外墙外保温系统有优良的相容性、匹配性及协同增效性。