成型前后活性炭储氢性能的初步研究

初步分析成型措施对活性炭储氢特性的影响.首先,在温度区间113～293 K、压力范围0～12.5 MPa测定氢平衡吸附数据,比较氢在未成型和经丙烯酸甲脂乳胶粘合剂成型的YK-1活性炭上的吸附量和等量吸附热;其次,通过储罐在室温、10.5MPa压力下的快速充/放气试验,分析成型措施对储罐吸附床吸附热效应的影响.结果表明,成型措施改变活性炭的密度和比表面积,使吸附量和吸附床中心在充放气过程的温度曲线以及吸附床的脱氢流率发生变化;在活性炭成型后,必须强化吸附床传热或引入吸附热管理措施以抑制吸附过程热效应.     

稠油注汽系统清洁替代储热系统设计

在大力推行新能源的背景下,太阳能光热是稠油注汽清洁替代的重要选择之一。针对油田稠油开采实现低碳转型的需求,分析稠油开采清洁替代的特点,以油田稠油注汽项目为例,简要分析包括熔融盐储罐、熔盐泵等在内的熔融盐储热系统的主要设备计算选型,测算熔融盐储热系统形成的蒸汽综合成本。研究表明,通过设计优化可以进一步控制系统投资。     

变质量体系能量转换及储存系统充能过程动态特性研究

给出了变质量体系能量转换及储存技术的基本概念．讨论了在变质量体系能量转换及储存技术充能过程中因质量变化所产生的内部扰动的系统充能过程的动态特性。结果表明，当充能始、终溶液储罐内溴化锂质量分数差为0．11时，蓄能系统中仅用了一个0．6m^3的溶液储罐和一个0．17m^3的水储罐可储存109kWh的制冷潜能，转移电网负荷23．3kWh，蓄能系统运行的COP值可达到4．67。     

车载高压氢气分级充注系统的设计与模拟

研究单级氢气充注时,氢气充注速率、初始温度和压力对氢气终了温度的影响。通过调用NIST REFPROP 中标准氢状态方程,模拟氢气在充注过程温度、压力、充注率等参数的变化。设计和模拟两级和三级氢气充注系统。结果表明：多级充注时,存在最佳的中间压力,使得充灌终了氢气温度最低,且增加级数可降低终了氢气温度。最后,对多级充注系统的能耗进行分析,结果表明随着级数的增加,系统的总能耗降低。     

金建祥:国内熔融盐储能技术已趋成熟

<正>中控德令哈10 MW塔式熔融盐太阳能热发电站项目是我国首个投入运行的以熔融盐为传热和储热介质的塔式项目,也是继西班牙Gemasolar、美国Crescent Dunes之后全球第3座商业化运行的熔融盐塔式电站。该电站是浙江中控在水工质塔式太阳能热发电站的基础上改造而来的,将水工质替换为主要通过双储罐结构,以二元硝酸盐作为吸热、储热介质,利用大规模定日镜场收集太阳能,将熔融盐加热并进行储存,     

压缩空气储能系统的理论分析及性能研究

压缩空气储能技术和抽水蓄能技术是两种最具潜力的电能规模化储存技术。构建了四套压缩空气储能方案,结合热力学第一定律对高压储罐内压缩空气的温度与压力参数的变化规律以及不同储能方案性能进行了比较。研究结果表明,高压储罐在与环境换热较差时,高压储罐的充气过程会经历较为明显的温升现象。200 m3储罐以1.0 kg/s流速充气至10 MPa时,温升幅度为22.46 ℃,储气过程的温升现象降低了储罐的空气容纳能力。在压缩空气储能系统性能方面,四套储能系统的热耗位于4 100 kJ/kW·h至4 200 kJ/kW·h之间,系统效率位于52.30%与56.33%之间。在储能系统效率与对外输出电能总量指标上,高压储罐与环境之间换热性能较好的储能系统均要优于换热条件较差的储能系统。     

相变蓄热供热装置热性能试验研究与系统经济性分析

为分析相变蓄热装置在充热和放热过程中的热性能,设计并搭建一套相变蓄热供热装置中试实验系统,研究主要运行参数对相变蓄热装置热性能的影响;在此基础上,结合项目案例,对相变蓄热供热系统经济性进行分析。结果表明：相变材料(Phase Change Material, PCM)凝固过程中的传热主要受相变介质内部导热控制;而在其熔化过程中自然对流对传热起重要控制作用;蓄热装置充热速率快于放热速率。提高传热流体流量有助于增强PCM中的热传递,缩短充/放热时间,但蓄热装置内PCM温度分布均匀性有所降低;为降低系统能耗,提高储放热效率,优先选用小流量进行充/放热。该相变蓄热供热项目的动态投资回收期为3.55年,具有良好的经济性。研究结果可对相变蓄热供热系统的设计及应用推广提供参考依据。     

安全仪表系统在二次再热机组的应用研究

  目的  安全性是电力行业永恒的主题,安全仪表系统是保证机组安全性的重要手段之一。国际上,安全仪表系统已有较为成熟的标准体系且得到广泛应用,而在国内火电行业的应用仍处于探索阶段。为推广安全仪表系统在电力行业应用,将描述其在火电二次再热机组的实际应用案例,为其它火电工程的设计、采购和运行维护提供参考。  方法  首先详细介绍和分析了相关国际规范,然后介绍了安全仪表系统在二次再热1 000 MW机组电厂项目的应用情况,并使用风险图表法对电厂进行安全完整性等级分析。  结果  通过分析等级并应用于二次再热1 000 MW机组电厂的设备招标、设计、调试、运行等,有效提高了电厂运行的安全稳定。  结论  在电力工程前期对机组安全仪表系统进行分析有利于电厂全生命周期的管理设计过程,应广泛应用于电力行业。     

熔盐储罐预热过程优化研究

基于CFD方法研究阶梯式预热过程中熔盐储罐温度分布和热应力分布,并分析温度端差和预热气体入口流量等参数对预热时间和罐体最大热应力的影响。结果表明：温度端差和质量流量各增加1倍时,预热时间分别缩短78.1%和61.5%,温度端差比质量流量对熔盐储罐预热过程的影响更显著。     

城市污泥热解特性及热解过程中Pb、Cd迁移特性

以城市污泥为研究对象,考察了其在不同升温速率下的热解特性、热解反应动力学特征以及重金属Pb和Cd在热解过程中的迁移规律。通过热解失重曲线图得出,污泥的热解过程可分为水分析出阶段、挥发分析出阶段和半焦分解阶段。提高升温速率会导致污泥的失重量减少,挥发分最大失重速率增加。根据Coats-Redfern积分法计算结果得到,挥发分析出的第1阶段和第2阶段的反应级数分别为1和2,且不同升温速率下挥发分析出的第1阶段和第2阶段下的活化能总体上变化不大。通过管式炉热解实验可知,在热解温度为400、500、600和700℃范围内,重金属Pb和Cd的残留率随热解温度的升高均表现为先上升后下降的规律。Cd的残留率在热解温度为500和700℃时分别达到最高(41.64%)和最低(2.92%),而Pb的残留率随温度变化不大,均为93%以上。热解温度为400~500℃,Cd和Pb挥发较少。     

Experimental Study on Melting Process in an Industrial Level Molten Salt Tank

Thermal energy storage(TES) is an important part of concentrating solar power(CSP) plants. The primary advantage of TES in CSP plants is the ability to dispatch electrical output to match peak demand periods and reduce the levelized cost of electricity. The major challenge of the molten salt is its high freezing point, leading to additional complicating freeze protection. This paper presents the experimental results of melting process of a mixed nitrate salt with a melting temperature of 115℃ in a 20 m^3 industrial level tank. Twenty electrical heaters inside the tank are used to heat the salt with a total maximum input power of 240 kW. In order to ensure a safe and fast melting process, the whole process adopted an operating strategy of combining automatic control with manual control. The whole melting process lasted for 314 hours. The salt temperature showed the greatest increase in the first 38 hours. Finally, an economic operation mode of molten salt heat storage tank was obtained.     

大直径高温熔盐储罐罐顶接管的强度及罐体稳定性分析

随着可再生能源技术的大力发展与应用,对太阳能热发电站中持久储热的钢制储罐的安全性能进行研究具有重要意义。以青海省某塔式太阳能热发电站中直径为25 m的高温熔盐储罐(储热罐)为例,利用ANSYS软件的平面实体轴对称单元建立了储罐有限元模型,着重对储罐顶部与熔盐管道接口处进行了强度和稳定性分析,通过对管道连接部位进行局部精细化建模,施加管口荷载,得到了储罐罐顶及罐体的等效位移、vonMises等效应力分布规律,以及该荷载对罐顶和罐体的屈曲临界荷载的影响。分析结果对今后大直径高温熔盐储罐的设计及施工具有一定的指导意义。     

Impact of refueling parameters on storage density of compressed hydrogen storage Tank

Hydrogen fuel cell vehicle (HFCV) is one of the key contributors to sustainable development of the society. For commercial deployment and market acceptability of fuel cell vehicles, efficient storage of hydrogen with an optimum refueling is one of the important challenge. Compressed hydrogen storage in Type IV tanks is a mature and promising technology for on-board application. The fast refueling of the storage tank without overheating and overfilling is an essential requirement defined by SAE J2601. In this regard, station parameters such as hydrogen supply temperature, filling rate and vehicle tank parameters such as filling time strongly influences the storage capacity of the tank, affecting driving range of the fuel cell vehicle. This paper investigates the impact of these parameters on storage density of the tank defined in terms of state of charge. For this, refueling simulation based on SAE J2601 protocol has been performed using computational fluid dynamic approach to investigate the influence of station parameters on storage density of the tank. Further, the root cause analysis was carried out to investigate the contribution of station and vehicle tank parameters for enhancing the storage density of the tank. Finally, the regression model based on these refueling parameters was developed to predict the density attained at different filling conditions. The results confirmed the strong contribution of pressure, filling time, supply temperature and least contribution of temperature, filling rates in enhancing the storage density of the tank. The results can provide new insight into refueling behavior of the Type IV tank for fuel cell vehicle.     

The design and optimization of a cryogenic compressed hydrogen refueling process

Cryo-compressed hydrogen storage has excellent volume and mass hydrogen storage density, which is the most likely way to meet the storage requirements proposed by United States Department of Energy（DOE）. This paper contributes to propose and analyze a new cryogenic compressed hydrogen refueling station. The new type of low temperature and high-pressure hydrogenation station system can effectively reduce the problems such as too high liquefaction work when using liquid hydrogen as the gas source, the need to heat and regenerate to release hydrogen, and the damage of thermal stress on the storage tank during the filling process, so as to reduce the release of hydrogen and ensure the non-destructive filling of hydrogen. This paper focuses on the study of precooling process in filling. By establishing a heat transfer model, the dynamic trend of tank temperature with time in the precooling process of low-temperature and high-pressure hydrogen storage tank under constant pressure is studied. Two analysis methods are used to provide theoretical basis for the selection of inlet diameter of hydrogen storage tank. Through comparative analysis of the advantages and disadvantages of the two analysis methods, it is concluded that the analysis method of constant mass flow is more suitable for the selection in practical applications. According to it, the recommended diameter of the storage tank at the initial temperature of 300 K, 200 K and 100 K is selected, which are all 15 mm. It is further proved that the calculation method can meet the different storage tank states of hydrogen fuel cell vehicles when selecting the pipe diameter.     

蓄能互联热泵系统相变装置熔化与凝固过程特性分析

介绍了一种新型的蓄能互联热泵系统.利用数值模拟的方法对填充石蜡C17的球型蓄热单元的熔化与凝固过程进行研究,分析了球壁温度、相变单元尺寸和相变材料初始温度三种影响因素对熔化过程和球壁温度对凝固过程的影响.通过对两个过程对比发现相变单元尺寸对相变过程影响最大,在相同温差条件下完全熔化时间少于完全凝固时间,熔化过程中始终存...     

塔式熔盐太阳能光热电站蒸汽发生器传热数值模拟设计计算

采用数值模拟的方式研究了50 MW塔式熔盐太阳能光热发电蒸汽发生系统蒸发器传热计算过程,利用Fluent软件建立三维模拟,通过合理的假设对蒸发器传热过程进行求解。计算结果表明:计算机数值模拟计算方法能够较好地反应蒸发器的真实传热过程,与传统理论计算、商业软件和实验数据有较好的契合度,表明数值模拟计算方法能够作为一种太阳能光热蒸汽发生器性能设计和优化的有效方法。     

Investigation on no-vent filling process of liquid hydrogen tank under microgravity condition

In order to investigate the no-vent filling performance under microgravity, the computational fluid dynamic (CFD) method is introduced to the study, where a model aiming at filling a liquid hydrogen (LH₂) receiver tank is especially established. In this model, the solid and fluid regions are considered together to predict the coupled heat transfer process. The phase change effect during the filling process is also taken into account by embedding a pair of mass and heat transfer models into the CFD software FLUENT, one of which involves liquid flash driven by pressure difference between the fluid saturated pressure and the tank pressure, and the other one indicates and calculates the evaporation–condensation process driven by temperature difference between fluid and its saturated state. This CFD model, verified by experimental data, could accurately simulate the no-vent filling process with good flexibility. Moreover, no-vent filling processes under different gravities are comparatively analyzed and the effects of four factors including inlet configuration, inlet liquid temperature, initial wall temperature and inlet flow rate, are discussed, respectively. Main conclusions could be made as follows: 1) Compared to the situations in normal gravity, the no-vent filling in microgravity experiences a more adequate liquid–vapor mix, which results in a more steady pressure response and better filling performance. 2) Inlet configuration seems to have negligible effect on the no-vent filling performance under microgravity since liquid could easily reach the tank wall and then cause a sufficient fluid-wall contact under any inlet condition. 3) Higher initial tank wall temperature may directly cause a higher pressure rise in the beginning, while this effect on the final pressure is not significant. Sufficient precooling and reasonable inlet liquid subcooled degree are suggested to guarantee the reliability and efficiency of the no-vent fill under microgravity.     

Towards fast and safe hydrogen filling for the fuel vehicle: A variable mass flow filling strategy based on a real-time thermodynamic model

Dealing with the conflict between the temperature/pressure rise and the total mass of hydrogen is a key challenge for rapid hydrogen filling of the hydrogen storage tank (HST). The temperature/pressure rise and total mass of hydrogen cause safety risks because of the former and limited cruise as the result of the latter. Therefore, safe hydrogen filling strategy is essential for the promotion of hydrogen fuel cell vehicles (FCVs). The existing thermodynamic model of the hydrogen storage tank is simplified either in the hydrogen state or the heat conduction of the HST wall, which can be hardly used as the real-time and accurate references for developing the filling strategy. To solve this problem, this paper works out the mathematical expression of a HST thermodynamic model. With the proposed HST thermodynamic model, a variable mass flow hydrogen filling strategy is developed. The results show that at the mass flow (12  g/s), the errors of the thermodynamic model are 7.1% and 6.8% for the temperature and pressure rise, compared with the computational fluid dynamics (CFD) model. At the mass flow (4.84  g/s), the thermodynamic model errors are 8.3% and 7.1% for the temperature and pressure rise, compared with the experimental data. Also, compared with the rule-based hydrogen filling strategies, the final state of charge (SoC) with the new filling strategy improve by 3%, 3.7%, and 2.7% at different initial temperatures, different volumes, and initial SoCs, respectively.     

Three dimensional numerical computations on the fast filling of a hydrogen tank under different conditions

Hydrogen-fueled vehicles offer a clean and efficient alternative for transportation. Compressed gas in high pressure tanks is a popular storage mode for hydrogen fuel. Time required for filling a hydrogen tank for vehicular applications should be short. But quick filling of hydrogen tanks at high pressures can result in high gas temperatures which can damage the tank and lead to its rupture. Hence the real time monitoring of gas temperature is essential during filling. This paper reports the findings of numerical simulation of filling process of hydrogen tanks. Real gas effects are considered. Local temperature distribution in the tank is obtained at different durations of the fill. Effect of changes in ambient temperature and initial and inlet gas temperatures is studied. Results of the study can aid in optimizing the filling time and in identifying the most suitable locations for the feedback devices within on-board hydrogen tanks.