熔盐槽式光电发热电站与熔盐蓄热储能系统的研究

介绍了熔盐槽式光热发电站的结构特点,分析了熔融盐槽式电站管路系统的运行方式,讨论了真空集热管的涂层薄膜、增透膜、熔封连接、烘烤抽真空等制作技术,研究了熔盐蓄热储能循环系统的设计开发过程,探讨了太阳能集热器和太阳能集热场的计算机智能控制方法。     

熔盐储能技术的研究及熔盐供暖技术的应用前景

液态熔盐由于体热容量大;低粘度、流动性好;低蒸汽压;较宽的工作温度范围;同时还具有较大的裂变材料溶解度,可用于熔盐堆中的最为燃料溶剂;是核能及太阳能传蓄热应用中良好的热工介质。本文结合典型熔盐的特点及应用对熔盐储能技术的研究进展进行了综述,并重点介绍了熔盐供暖技术的应用前景。熔盐储能供热利用熔盐极佳的储热特性,具有安全、环保、经济等特性,是目前最具竞争优势的供热方式。     

熔盐技术在新能源中的应用现状

随着科技的发展,熔盐以其独特的优势不断地应用于新能源领域。综述了熔盐技术在太阳能光热发电领域蓄热储能、新能源电池(燃料电池、锂电池)、熔盐反应堆的应用现状以及熔盐的研究现状,分析了目前面临的问题以及未来的发展方向。指出,熔盐由于具有较强的腐蚀性,要求反应器材料必须具备抗高温、耐腐蚀、保温性能好等特点,因此材料问题还需要不断地探索和改进;另外,熔盐混合配比也是未来研究的重点。     

太阳能光热熔盐发电技术的研究与开发

介绍了三元混合熔盐和二元混合熔盐的配方比例,对光热发电中熔盐蓄热储能系统的工艺流程进行了设计开发,介绍了熔盐设备和管道的制作材料,总结了熔盐循环系统在开车启动和停车过程中进行熔盐预热融化以及伴热保温的注意事项,分析了高温熔盐液下泵的结构型式和设计方法。最后,对光热发电站中熔盐贮罐的设计进行了分析研究,讨论了防止熔盐凝固的电伴热系统的设计方案,分析了光热发电站系统的整体与远程温度监测和控制方法。     

熔盐储热材料比热容强化的研究进展

强化熔盐材料比热容可以有效增强熔盐材料的蓄热能力,减小蓄热系统面积及热损失,进而降低蓄热成本,是近年来中高温储能领域的研究热点。本文主要从熔盐储热材料比热容强化的必要性、强化方法和强化机理等方面综述了近年来熔盐传热蓄热材料比热容强化的研究进展。具体阐述了添加可溶性添加剂和掺杂异质纳米颗粒形成纳米流体两种强化熔盐比热容的方法及目前存在的问题,重点探讨了熔盐纳米流体的制备方法、异质纳米颗粒体系、强化效果及比热容强化机理等问题。此外,指出了当前利用纳米流体强化熔盐储热材料比热容方面存在的不足：研究体系单一、悬浮稳定性差和比热容强化机理不完善等,并对熔盐纳米流体的未来发展方向,即多体系熔盐纳米流体的开发,多手段比热容强化机理的揭示和多方法熔盐纳米流体物性的测量进行了展望。     

多孔介质蓄热过程中的非热平衡温差分析

蓄热技术是可再生能源大规模工业化应用的有效手段,可以稳定热能的连续供应和延长工作时间,应用于太阳能高温热发电中的单罐斜温层蓄热系统越来越受到重视。文章从非热平衡理论和数值计算方面对蓄热过程中传热流体和蓄热固体的温差进行了研究,分析了蓄热过程中高温熔盐的流速、蓄热球颗粒直径等参数对两相之间温差的影响。结果表明熔盐流速或颗粒直径越大,则温差越大,局部非热平衡越明显。     

泡沫金属在熔盐相变蓄热中的强化传热特性

搭建了熔盐蓄热特性实验平台,开展相变蓄热过程传热特性实验研究。建立了蓄热容器二维轴对称、瞬态固液相变数学模型,相变过程模拟采用Solidfication & melting模型,相变区域采用Boussinesq近似,对比了纯硝酸盐蓄热工况和填加泡沫金属后蓄热工况数值模拟结果。采用实验与数值模拟相结合的方法,重点分析了泡沫金属对熔盐蓄热过程的强化传热作用。结果表明,填加泡沫金属能够有效提高熔盐换热速率,泡沫金属孔隙率越小强化蓄热效果越显著。泡沫铜的热导率较高,相对于泡沫镍和泡沫铝有更好的强化传热效果,蓄热速率是纯硝酸盐蓄热的1.6倍。在相变蓄热后期自然对流换热占主导地位,此时泡沫金属会抑制自然对流。同时,填加的泡沫金属越靠近容器中心位置,对自然对流抑制作用越强,蓄热性能越差。     

一种太阳能高温蓄热碳酸熔融盐的实验研究

为了满足太阳能高温传热、蓄热的要求,采用静态高温混合熔融法制备了主要由碳酸钠、碳酸钾和添加剂Ad组成的混合熔盐。通过热重分析(TG)和差示扫描量热(DSC)等方法确定了混合熔盐的熔点、相变潜热、分解温度和初晶点等数据,并采用了X-射线衍射(XRD)分析法分析了混合熔盐在高温条件下的热稳定性。实验最终确定了该混合熔盐的最佳使用温度为433~780℃,可以作为太阳能高温传热、蓄热介质来应用。     

熔盐储能材料在太阳能光热发电中的应用

简述了熔盐储能材料,对熔盐储能材料在太阳能光热发电中的应用情况与市场进行了较全面的分析,对熔盐生产企业提出了建议。     

高温熔盐在太阳能热发电中的应用

高温熔盐蓄热技术是熔盐在新领域的又一应用,有着广阔的发展前景。本文介绍了高温熔盐的特性及常见熔盐的种类,比较其性能的优缺点,重点探讨了硝酸熔盐在太阳能热发电中的应用。通过实例的具体数据,对其应用的可行性进行了分析,结果表明硝酸熔盐更能减少发电系统成本,将是今后太阳能热发电中主要的蓄热和传热材料。     

太阳盐/钢渣定型复合相变储热材料的制备与性能研究

全球范围内的能源短缺和环境污染问题迫使人们积极开发可再生新能源.储热技术是解决新能源不稳定性问题的关键技术.相变材料是重要的储热介质之一.熔盐相变材料因其储热密度高,可操作温度范围广的优势,成为储热材料领域研究的热点.为解决熔盐液相易泄漏、低导热和高成本的问题,选择钢渣为基体材料,制备了太阳盐/钢渣定型复合相变储热材料...     

Acceleration of thermal decomposition of molten nitrates by Cr in steel and promotion of this effect by halogens

Molten salts have been widely studied as the most common heat storage medium for concentrated solar power (CSP) plants. However, most studies have focused on the corrosiveness of molten salts, while this study innovatively reveals the role of stainless steel in promoting the decomposition of molten salts and the mechanism by which the halogen ions accelerate this process. Considering commercial Solar Salt as an example, the thermal stability, composition, and thermophysical properties of Solar Salt adding Cl⁻, Br⁻, and I⁻ after contacting different stainless steel were analyzed. The results showed that Cr was the main reason for the decomposition of the molten salt, and Cl⁻, Br⁻, and I⁻, all accelerated the decomposition. Meanwhile, different halogen ions promoted the decomposition of molten salts through different mechanisms: oxide layer destruction and chain oxidation.     

Molten Salt Storage for Power Generation

Storage of electrical energy is a key technology for a future climate-neutral energy supply with volatile photovoltaic and wind generation. Besides the well-known technologies of pumped hydro, power-to-gas-to-power and batteries, the contribution of thermal energy storage is rather unknown. At the end of 2019 the worldwide power generation capacity from molten salt storage in concentrating solar power (CSP) plants was 21 GWh_el. This article gives an overview of molten salt storage in CSP and new potential fields for decarbonization such as industrial processes, conventional power plants and electrical energy storage.     

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。     

Optimal coupling of a biomass based polygeneration system with a concentrated solar power facility for the constant production of electricity over a year

In this paper we address the integration of a polygeneration system based on biomass with a concentrated solar power facility for the constant production of electricity over a year long. The process is modelled as a superstructure embedding two different gasification technologies, direct and indirect, and two reforming modes, partial oxidation or steam reforming followed by gas cleaning and three alternatives for the syngas use, water gas shift reactor (WGSR) to produce hydrogen, a furnace for thermal energy production and an open Brayton cycle. We couple this system with a concentrated solar plant that uses tower technology, molten salts and a regenerative Rankine cycle. The problem is formulated as a multi-period mixed-integer non linear programming problem (MINLP). The optimal integration involves the use of indirect gasification, steam reforming and a Brayton cycle to produce 340 MW of electricity at 0.073 €/kWh and 97 kt/yr of hydrogen as a credit.     

蓄热技术在聚焦式太阳能热发电系统中的应用现状

从了解聚焦式太阳能热发电（CSP）的发展背景出发,综述了CSP系统中的蓄热技术的应用现状与发展方向,对各种蓄热技术进行了比较,并简要介绍了我国目前技术发展的现状,同时指出经济型的蓄热系统设计是CSP系统成功走向市场化的关键技术,双罐熔融盐直接蓄热塔式系统将是我国发展CSP技术努力的方向。     

聚光式太阳能热发电中传热工质的研究现状

聚光式太阳能热发电系统的传热工质主要包括水／水蒸气、空气、导热油、液态金属和熔盐。针对传热工质的物性·提出了各传热工质的优缺点,介绍了传热工质在太阳能热发电中的应用现状及研究情况,指出熔盐将是未来太阳能热发电传热蓄热工质发展的重点。     

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     

蓄热技术的研究进展与应用

综述了蓄热技术的研究概况和发展现状，详细介绍了在工业，电力和空间中的应用，并展望了今后的研究和发展方向。     

Polymer-derived silicon nitride aerogels as shape stabilizers for low and high-temperature thermal energy storage

This work presents a new skeleton material for thermal energy storage (TES), a silicon nitride aerogel obtained through the pyrolysis of a pre-ceramic polymer. Silicon nitride offers a good combination of thermal conductivity, high-temperature resistance, and chemical inertness. The aerogel porosity can be spontaneously infiltrated with molten NaNO₃, which is a typical phase change material (PCM) in high-temperature TES. The Si₃N₄/NaNO₃ composite exhibits excellent thermal properties with a thermal energy storage efficiency of 82 %, a limited molten salt leakage, and good stability to thermal cycling. The aerogel withstands oxidation up to high temperature and is chemically inert even in contact with salts. This novel aerogel shows also a notable paraffin absorption ability (used in room temperature TES) with negligible leakage even when in contact with absorbent paper. The so-obtained composite reached ≈ 82.4 vol % of organic PCM and a thermal energy storage efficiency of ≈ 62 % compared to neat paraffin.