风光氢综合能源系统设计及运行集成优化

基于风光制氢和燃料电池热电联供的风光氢综合能源系统是消纳富余可再生能源、减少弃风弃光的有效途径,实施系统设计及运行集成优化,对提高综合能源利用率、降低系统经济成本具有重要意义。通过构建风光氢综合能源系统设计及运行集成优化模型,对系统各设备的容量配置方案及典型运行策略进行了优选,并且系统比较了不同风光资源及用能负荷特性下系统设计及运行方案的差异。结果表明：风光氢综合能源系统在办公楼负荷场景和风光资源更丰富的地区获得了更优的经济性。     

风光氢综合能源系统设计及运行集成优化

基于风光制氢和燃料电池热电联供的风光氢综合能源系统是消纳富余可再生能源、减少弃风弃光的有效途径.实施系统设计及运行集成优化,对提高综合能源利用率、降低系统经济成本具有重要意义.通过构建风光氢综合能源系统设计及运行集成优化模型,对系统各设备的容量配置方案及典型运行策略进行了优选,并且系统比较了不同风光资源及用能负荷特性下...     

电力简讯

新型超薄固体氧化物燃料电池氢耗尽后仍可发电据《中国科学报》2012年8月2日报道:哈佛大学材料科学家通过采用低温运行和使用纳米结构氧化钒作为阳极材料,研发出一种新型固体氧化物燃料电池(SOFC),既可发电,也可以存储电化学能量,即使氢燃料耗     

电热气氢综合能源系统随机优化调度

首先,分析电解槽以及燃料电池等设备工作特点,计及设备的动态能效,建立氢系统设备的精细化模型;其次,建立各种能源间的耦合关系模型,通过电热氢多种储能实现电热气氢系统的能量平衡;最后,计及电热气负荷的波动与可再生能源的不确定性,以日运行成本最小为目标,建立电热气氢综合能源系统随机优化调度模型。算例分析验证了该优化模型能有效消纳风光资源、降低日运行成本、减少环境污染,具有较好的经济性与环保性。     

浙江湖州首台氢燃料电池测试车试制成功

近日,氢云链从湖州市吴兴区获悉,浙江湖州市首台氢燃料电池测试车在吴兴试制成功,预计今年上半年可投入运行,这标志着湖州市已基本建成氢燃料电池车产业链条。这台氢燃料电池测试车的氢燃料电池由浙江比洛德新能源有限公司研发,历时4年多,该公司拥有完全自主知识产权氢燃料电池系统,整车动力及供给系统已经由传统的发动机、燃油箱等变成了氢燃料电池氢堆、储氢罐等。     

基于价值损耗的燃料电池混合动力能量管理策略评价

为了评价燃料电池混合动力系统能量管理策略的经济性,对基于状态机和模糊逻辑2种能量管理策略的燃料电池混合动力叉车的价值损耗进行分析。首先,通过分析燃料电池和锂电池的工作特性,分别构建依赖实际工况的燃料电池单体电压衰减率模型和锂电池容量衰减率模型;同时定义计及燃料电池氢耗量的燃料电池混合动力系统的综合价值损耗指标。其次,通过测试叉车极限工况,计算燃料电池功率和锂电池容量,并根据母线电压确定锂电池SOC范围。最后,设计基于状态机和模糊逻辑的2种燃料电池混合动力叉车能量管理策略,并通过仿真分析在叉车一次循环工况下2种能量管理的价值损耗。研究结果表明:相较于模糊逻辑策略,采用状态机策略造成燃料电池寿命损耗提高7.81%,氢耗量提高1.89倍,锂电池寿命损耗减小21.33%。     

面向车载深冷高压供氢系统的控制策略研究

提出一种深冷高压储供氢系统的实时控制策略,用于管理控制燃料电池卡车的氢能储供过程。首先,基于流体热力学模型建立深冷高压储氢瓶泄放模型,预测氢的状态参数变化。其次,结合车辆热管理系统,设计一种新型深冷高压氢供给系统,综合利用燃料电池"废热"和深冷高压"冷能"。最后,通过数值建模对换热器运行参数进行定量研究,优化了控制策略。整体动态响应机制既满足了燃料电池正常运行的要求,又提升了整车能量利用率。     

风氢耦合系统能量管理策略研究

针对风力机出力的波动性和并网弃风问题,采用风力机/电解槽/燃料电池/超级电容的风氢耦合发电系统及其能量管理控制策略。针对风氢耦合发电系统的12种运行模式,提出一种能量管理控制策略,确保在各个控制单元的作用下,能量协调流动于各个子单元间。能量管理控制策略不仅使风氢耦合发电系统出力可控,而且平抑了直流母线电压波动,平滑了上网功率。通过Matlab/Simulink软件进行仿真研究,验证了风氢耦合发电系统的能量管理控制策略的有效性,提高了风电消纳能力。     

有机液体与储氢材料组成的浆液储氢体系的能量分析

对C6H6/C6H12-LaNi5/LaNi5H6-H2组成的浆液储氢体系的储、放氢过程进行了能量衡算,提出了两种车载氢源系统的概念设计:随车脱氢和随车加氢-脱氢系统。考察了两种车载氢源系统的脱氢转化率和系统运行过程中放出的废热利用率对整个车载氢源系统热效率的影响,并就两种车载浆液氢源系统与氢内燃机或燃料电池构成的氢能汽车动力系统的能效进行了评估。研究表明,无论是采用氢内燃机还是燃料电池作为氢能汽车的动力驱动方式,车载浆液氢源系统在能效上是经济、可行的。     

单原子催化剂在氢燃料电池阴极氧还原反应中的研究进展

氢燃料电池是一种高效、环境友好以及零碳排放的能量转化技术,然而高成本的贵金属催化剂阻碍了其规模化应用。单原子催化剂因具有高原子利用率、高催化活性和选择性、低成本等优点,对氧分子表现出优异的催化还原性能,在氢燃料电池中具有广阔的应用前景。如何设计合成高效和低成本的单原子催化剂成为该领域的研究热点。重点综述贵金属单原子催化剂和非贵金属单原子催化剂在氢燃料电池阴极氧还原反应中的研究进展,总结提出增强单原子催化剂氧还原性能的调控策略,包括配位结构、局域环境、双原子对、缺陷位点以及暴露活性位点等调控机制,为从原子尺度设计高效氧还原催化剂提供了思路借鉴,并对氢燃料电池氧还原单原子催化剂的发展机遇与挑战进行了展望。     

Optical properties and thermal stability of pulsed-sputter-deposited AlxOy/Al/AlxOy multilayer absorber coatings

Spectrally selective Al_xO_y/Al/Al_xO_y multilayer absorber coatings were deposited on copper (Cu) and molybdenum (Mo) substrates using a pulsed sputtering system. The Al targets were sputtered using asymmetric bipolar-pulsed DC generators in Ar+O₂ and Ar plasmas to deposit an Al_xO_y/Al/Al_xO_y coating. The compositions and thicknesses of the individual component layers were optimized to achieve high solar absorptance (α=0.950-0.970) and low thermal emittance (ε=0.05-0.08). The X-ray diffraction data in thin film mode showed an amorphous structure of the Al_xO_y/Al/Al_xO_y coating. The X-ray photoelectron spectroscopy data of the Al_xO_y/Al/Al_xO_y multilayer absorber indicated that the Al_xO_y layers present in the coating were non-stoichiometric. The optical constants (n and k) of the multilayer absorber were determined from the spectroscopic ellipsometric data. Drude's free-electron model was used for generating the theoretical dispersion of optical constants for Al films, while the Tauc-Lorentz model was used for modeling optical properties of the dielectric Al_xO_y layers. In order to study the thermal stability of the Al_xO_y/Al/Al_xO_y coatings, they were subjected to heat treatment (in air and vacuum) at different temperatures and durations. The multilayer absorber deposited on Cu substrates exhibited high solar selectivity (α/ε) of 0.901/0.06 even after heat-treatment in air up to 400 °C for 2 h. At 450 °C, the solar selectivity decreased significantly on Cu substrates (e.g., α/ε=0.790/0.07). The coatings deposited on Mo substrates were thermally stable up to 800 °C in vacuum with a solar selectivity of 0.934/0.05. The structural stability of the absorber coatings heat treated in air (up to 400 °C) and vacuum (up to 800 °C) was confirmed by micro-Raman spectroscopy measurements. Studies on the accelerated aging tests suggested that the absorber coatings on Cu were stable in air up to 75 h at 300 °C and the service lifetime of the multilayer absorber was predicted to be more than 25 years. Further, the activation energy for the degradation of the multilayer absorber heat treated for longer durations in air is of the order of 64 kJ/mol.     

Hydrogen storage properties of multi-principal-component CoFeMnTixVyZrz alloys

This study presents an innovative multi-principal-element CoFeMnTiVZr alloy system for the absorption and desorption of hydrogen. Pressure-composition-isotherms (PCIs) demonstrate that CoFeMnTi_xVZr, CoFeMnTiV_yZr, and CoFeMnTiVZr_z can absorb and desorb hydrogen for x, y, and z that satisfy 0.5 ≤ x ≤ 2.5, 0.4 ≤ y ≤ 3.0, and 0.4 ≤ z ≤ 3.0, respectively. X-ray diffraction (XRD) reveals that CoFeMnTi_xV_yZr_z alloys have a simple C14 Laves phase with a single set of lattice parameters before and after PCI tests. The distributions of each element in CoFeMnTi_xV_yZr_z alloys are roughly equal, as revealed by SEM/EDS mapping. The effects of values x, y, and z on the hydrogen storage properties are elucidated in terms of lattice constant, element segregation, hydride formation enthalpies of the alloy components and hydrogen, and the averaged formation enthalpy. The high-entropy effect promotes the formation of a single C14 Laves phase, and the maximum hydrogen storage capacity is strongly related to the hydride formation enthalpy of the alloy and hydrogen.     

Explosion behavior of CH4/O2/N2/CO2 and H2/O2/N2/CO2 mixtures

In this work, the explosion behavior of stoichiometric CH₄/O₂/N₂/CO₂ and H₂/O₂/N₂/CO₂ mixtures has been studied both experimentally and theoretically at different CO₂ contents and oxygen air enrichment factors. Peak pressure, maximum rate of pressure rise and laminar burning velocity were measured from pressure time records of explosions occurring in a closed cylindrical vessel. The laminar burning velocity was also computed through CHEMKIN–PREMIX simulations.     

C/H/O/N/S/Cl/K/Na元素的详细化学反应机理的简化与验证

基于Senkin模型,应用自编化学反应机理简化程序,结合Kinalc和Mechmod开源程序,发展了详细化学反应机理的简化与验证方法.以电站锅炉燃烧的计算流体力学(CFD)数值模拟为应用背景,建立了考虑C/H/O/N/S/Cl/K/Na元素的详细化学反应机理(115组分,1,342基元反应),并运用此方法得到简化反应机理(28组分,20反应).验证结果表明,该简化机理在锅炉运行的主要参数变化范围内(温度T=1,100～1,500,℃,过量空气系数λ=0.8～1.2)具有较好的准确性和较高的计算效率,可应用于锅炉燃烧的CFD计算.     

Structural and transport properties of LixNi1−y−zCoyMnzO2 cathode materials

In this work structural and transport properties of layered LiNi_1−y−zCo_yMn_zO₂ (y = 0.25, 0.35, 0.5 and z = 0.1) cathode materials are presented. In the considered group of oxides, LiNi_1−y−zCo_yMn_zO₂, there is no clear correlation between electrical conductivity and the a parameter (M-M distance in the octahedra layers). A non-monotonic modification of electrical properties of Li_xNi_0.65Co_0.25Mn_0.1O₂ cathode materials is observed upon lithium deintercalation.     

Metal/CdTe/CdS/Cd1−xZnxS/TCO/glass: A new CdTe thin film solar cell structure

The potential of CdTe/CdS/Cd_1−xZn_xS structure as an alternative to CdTe/CdS structure in photovoltaic application has been demonstrated. The unoptimized solar cell structure grown on transparent conducting oxide coated soda lime glass of 3 mm thickness with no antireflection coating yielded a 10% efficiency. This efficiency is the highest ever recorded in any Cd_1−xZn_xS film containing CdTe solar cells.     

Preparation and electrochemical properties of layer-structured LiNi1/3Co1/3Mn1/3−yAlyO2

Layer-structured LiNi_1/3Co_1/3Mn_1/3−yAl_yO₂ has been synthesized via a sol–gel method. The lattice constants of LiNi_1/3Co_1/3Mn_1/3−yAl_yO₂ decrease with the concentration of aluminum ions. XANES analysis further confirms that the valence of cobalt ion is 3+, and that of Ni is between 2+ and 3+ in LiNi_1/3Co_1/3Mn_1/3−yAl_yO₂. With doping aluminum ions, the redox centers for the electrochemical reaction change from nickel ions alone to both nickel and cobalt ions. The amounts of de-intercalatable lithium ions are affected by the concentration of aluminum ions; however, the extracting efficiency of lithium ions is improved by doping aluminum ions. Among all the samples, LiNi_1/3Co_1/3Mn_0.23Al_0.1O₂ exhibits the best capacity retention and the least irreversible capacity.     

Experimental and modeling studies of C2H4/O2/Ar, C2H4/methylal/O2/Ar and C2H4/ethylal/O2/Ar rich flames and the effect of oxygenated additives

The addition of dimethoxymethane (DMM or methylal) and diethoxymethane (DEM or ethylal) to a rich ethylene/oxygen/argon flame has been investigated by measuring the depletion of soot precursors. Three rich premixed ethylene/oxygen/argon (with and without added methylal or ethylal) flat flames have been stabilized at low-pressure (50 mbar) on a Spalding–Botha type burner with the same equivalence ratio of 2.50. Identification and monitoring of signal intensity profiles of species within the flames have been carried out by using molecular beam mass spectrometry (M.B.M.S.). The replacement of some C₂H₄ by C₃H₈O₂ or C₅H₁₂O₂ is responsible for a decrease of the maximum mole fractions of the detected intermediate species. This phenomenon is noticeable for C₂–C₄ intermediates and becomes more effective for C₅–C₁₀ species, mainly when C₃H₈O₂ added.A new kinetic model has been elaborated and contains 546 reactions and 107 chemical species in order to simulate the three investigated flames: C₂H₄/O₂/Ar, C₂H₄/DMM/O₂/Ar and C₂H₄/DEM/O₂/Ar. The reaction mechanism well reproduces experimental mole fraction profiles of major and intermediate species, and underlines the effect of methylal and ethylal addition on species concentration profiles for these flames.     

Highly structured TiO2/In(OH)xSy/PbS/PEDOT:PSS for photovoltaic applications

A system of highly structured TiO₂/In(OH)_xS_y/PbS/PEDOT:PSS has been developed and investigated by photovoltage spectroscopy, X-ray photo- and Auger electron spectroscopies, electron microscopy, and photovoltaic response. TiO₂, In(OH)_xS_y, PbS, and PEDOT:PSS serve as electron conductor, buffer layer, absorber, and hole conductor, respectively. Both buffer and absorber layers were prepared by chemical bath deposition. The band gap of as-prepared In(OH)_xS_y varied between 2.4 and 3.5 eV depending on the pH-value of the solution. In addition, the band gap of the PbS could be widened to about 0.85 eV making the application as absorber for solar cells feasible. At present, corresponding solar cell devices reach short-circuit current densities of about 8 mA/cm² and open-circuit voltages of about 0.3 V.     

Burning velocities and kinetics of H2/NF3/N2, CH4/NF3/N2, and C3H8/NF3/N2 flames

The combustion characteristics and reaction mechanism of mixtures containing nitrogen trifluoride (NF₃) were investigated. Burning velocities for H₂/NF₃/N₂, CH₄/NF₃/N₂, and C₃H₈/NF₃/N₂ flames were determined for the first time at various equivalence ratios and N₂ mole fractions. The burning velocities of the latter two flames were similar and showed peaks at equivalence ratios of ∼1.0, while those of the H₂/NF₃/N₂ flames had the pronounced peak at low equivalence ratios where the formation of the wrinkled flames was observed. A detailed kinetic model was constructed to simulate the laminar burning velocities of H₂/NF₃/N₂ and CH₄/NF₃/N₂ flames. The model accurately reproduced the experimental results. Analyses of the reaction mechanism revealed the major reaction pathways that involve the decomposition of NF₃, the oxidation and chain-fluoridation of H₂ and CH₄, and the formation of N₂.