电能-甲醇跨区协同输运下的电-氢耦合系统调度

针对我国电氢供需时空分布不均导致新能源利用率低、系统运行成本过高等问题,提出一种电能-甲醇跨区协同输运下的电-氢耦合系统调度方法。首先,根据送、受端区域的能源供需特征、电/氢子系统运行特性及甲醇氢载体属性,设计电-氢耦合系统跨区协同运行机制和调度框架,提出电能-甲醇联合输运下的送、受端供需平衡模型,充分利用甲醇的灵活储运能力促进新能源跨时空消纳;然后,构建电能-甲醇跨区协同输运下的电-氢耦合系统双层优化调度模型,考虑长时间尺度下的电、氢能量平衡,以天为调度尺度建立上层模型,确定甲醇输运和机组起停方案;考虑短时间尺度下的电力平衡、氢供需平衡约束,以小时为调度尺度建立下层模型,确定送、受端系统各小时的运行计划,从而实现异质能源的跨时空协同互补,保障送、受端区域多时间尺度能量供需平衡;最后,基于改进的HRP 38系统进行仿真分析,结果表明电能-甲醇跨区协同输运能够显著提高系统经济运行水平,促进新能源规模化消纳。

计及能源自洽率和共享氢储能的电-氢-交通耦合配电网低碳经济运行

新型储能的多元化发展为能源资源的优化配置和就地高水平消纳奠定了基础,为此提出了一种计及能源自洽率和共享氢储能(shared hydrogenstorage,SHS)的能源网低碳经济调度方法。设计了包含电负荷-氢负荷的氢燃料电池车(hydrogen fuel cell vehicle,HFCV)交通网与新能源配电网双向耦合架构。在此基础上,以提高能源自洽率、降低碳排放成本为目标,综合考虑配电网、交通网、氢储能系统的运行约束条件以及短期氢储能(short-term hydrogenstorage,STHS)和SHS服务,建立了电-氢-交通耦合配电网的低碳经济优化调度模型,并给出了基于精英遗传算法(elitist strategy genetic algorithm,ESGA)的求解方法。算例分析证明,提出的方法可有效提升电-氢-交通耦合网络能源自洽率、降低整体系统碳排放成本。

基于多仿射决策规则的电-氢耦合系统多阶段鲁棒优化调度

在电-氢耦合系统优化研究中,现有工作未充分挖掘氢负荷灵活分配方式对提升系统运行经济性以及应对新能源发电不确定性的作用。文中分别刻画长管拖车运氢、管道运氢、就地售氢3种氢负荷的运行特性,构建了计及储氢特性的氢负荷在不同时段间优化分配策略。为应对新能源发电的不确定性,以氢负荷作为日前决策量,而储氢、制氢在日内随着随机变量的实现顺序决策,构建了电-氢耦合系统多阶段鲁棒优化问题。为解决传统单仿射决策规则保守性较强的问题,提出了基于多不确定性集的多仿射决策规则求解方法,对随机变量的不同实现采取不同的决策方式。仿真结果表明,氢负荷凭借储氢环节实现了灵活分配,提高了电-氢耦合系统运行的经济效益;多仿射决策规则所得结果的经济性优于单仿射决策规则,并为系统实时运行提供了调度方案。

考虑多约束条件下的电-氢-化耦合系统控制方法

在电-氢-化耦合系统中,电解水制氢装置在消纳风、光等可再生能源或参与电网平衡调控的同时,其变负载运行需满足多约束条件,以保证系统各环节安全稳定运行。针对电-氢-化耦合系统中各环节存在的耦合作用关系,详细介绍了系统核心环节——电解水制氢系统的模型,并提出一种考虑各环节多约束条件下的系统控制方法。对兆瓦级碱性电解槽的模型进行详细分析,包括电化学模型、热力学模型等,同时建立辅助设备压缩机、储氢罐的数学模型;综合考虑电解槽温度、电解槽压力、储氢罐压力、下游煤化工环节用氢等约束条件,提出电解水制氢系统的控制策略。基于MATLAB/Simulink搭建电-氢-化耦合系统的仿真模型,并通过RT-LAB半实物仿真平台,在不同的电网功率指令下,对电-氢-化耦合系统的运行特性进行深入研究,并对所提控制策略的控制效果进行验证。

基于代理拉格朗日松弛的电-氢耦合网络优化调度

针对电-氢耦合网络的调度问题,将电网与氢供应网协调优化,决定氢运输拖车的路径,并考虑氢运输的时效性,提出基于代理拉格朗日松弛的分布式求解方法。首先,考虑氢运输中拖车的行程和到达加氢站的时间等因素,以电网和氢供应网的运行成本最小为目标函数,建立电-氢耦合网络的混合整数线性规划调度模型;其次,根据代理拉格朗日松弛法将该调度问题分解成电制氢与氢供应子问题,并进行同步协调;最后,通过算例验证了所提模型及求解方法的有效性。

基于改进双层鲁棒的氢-电混合时间尺度联合储能系统规划

随着可再生能源并网比例持续提高,为平抑可再生能源发电波动的储能技术受到广泛的关注。氢储能作为一种新兴的储能方式可以实现长时间以及广域空间范围内的大规模电能量的转移,是消纳高比例可再生能源的重要技术。文中构建了包含电化学储能、氢储能及上级电网的氢-电联合耦合系统,构建了长期氢储能与短期电化学储能的长-短期混合时间尺度联合储能机制,建立了联合储能系统中各装置的数学模型。为降低常规双层鲁棒规划方法针对风/光/荷不确定性处理的复杂程度,克服对于求解器的依赖,提出了一种改进的双层鲁棒规划,充分计及了风/光/荷最不利的情况,实现了长短期的氢-电混合储能系统中的设备配置容量的规划。为分析氢储能在长时间尺度下充放能的过程,利用典型日权重系数法对典型日进行耦合,以较小的计算量来描述全年的氢储能充、放氢能量。针对某地区进行算例分析,并对其结果从系统各装置配置容量/功率、总成本及各装置功率时序进行比较分析,验证论文所述方法的可行性及有效性。

考虑电动汽车充电方式的热-电-氢耦合孤岛综合能源系统优化配置

为实现热-电-氢综合能源系统在满足多种负荷需求的同时,能有效地降低经济成本,提出了一种以经济性为目标的双层优化配置算法,研究了孤岛综合能源系统的优化配置。首先,搭建了热-电-氢混合耦合综合能源系统(the combined hydrogen,heat and power system,CHHP),然后考虑到设备购置、运维以及燃料电池、电解槽和蓄电池的老化建立了系统总目标函数。再采用上层算法为混合正余弦灰狼算法(gray wolf optimization with sine cosine algorithm,GWO-SCA),下层算法为混合整数线性规划(mixed integer linear programming,MILP)的双层优化配置算法对设备容量进行求解。最后运用算例,验证了该算法的优越性。并对系统中的电动汽车负荷考虑了多种充电方式,讨论了不同充电方式对配置结果和经济成本的影响。结果表明所提优化配置方法能够实现综合能源系统的经济、稳定运行。

电力系统氢储能关键应用技术现状、挑战及展望

深入挖掘氢储能在电力系统中的应用潜力,进而推进其在电力系统中的规模化应用是电力行业能源结构转型与深度脱碳的重要技术路径之一。为加速构建新型电力系统,该文首先归纳分析构建氢储能与电力系统耦合结构,并从电解水制氢、氢气储输、氢气发电和电解槽/燃料电池模型构建4个方面阐述氢储能关键技术发展现状;其次,以氢储能在电力系统“源–网–荷”各环节应用场景为主线,梳理回顾目前国内外电–氢耦合技术取得的进展;最后,对氢储能支撑新型电力系统构建中存在的技术挑战与未来重点技术发展方向展开探讨,旨在为电力系统中氢储能应用技术的研究提供借鉴与参考。

考虑低碳排放的并网型风电制氢加氢站优化运行

并网型风电制氢系统能满足加氢站的稳定加氢需求,因此有必要对并网型风电制氢加氢站的优化运行进行研究。建立了电-氢耦合模型,分别采用两个方案设定目标函数,考虑了电力功率约束、氢气容量约束和风电的零弃风运行等约束条件,采用改进粒子群算法求解上述模型。算例结果表明,所提求解算法收敛性较好。若仅考虑加氢站购电费用最小,会出现加氢站与电网的联络线功率波动较大的问题,对电网并不友好;若综合考虑购电费用和联络线波动性,虽加氢站购电费用小幅提升,但联络线功率波动性明显改善,对电网更友好。以目前的电-氢相互转换效率,两个方案中氢燃料电池都未参与考虑峰谷电价差的电量平移,也不参与联络线功率的平滑作用。

Preparation and Characterization of Tungsten-substituted Molybdophosphoric Acids and Catalytic Cyclodehydration of 1,4-Butanediol to Tetrahydrofuran

A series of tungsten-substituted molybdophosphoric acids(H3PMo12-nWnO40·xH2O) were synthesized and characterized by inductive coupled plasma atomic emission spectroscopy(ICPAES),thermal gravimetry and differential scanning calorimetry(TG-DSC),Fourier transform infrared spectroscopy(FTIR),X-ray diffraction(XRD),and FTIR pyridine adsorption.The as-prepared heteropoly acids have a Keggin type structure.The synthesis of tetrahydrofuran by reactive distillation and cyclodehydration of 1,4-butanediol was studied using the tungsten-substituted molybdophosphoric acids as catalysts.The results of catalytic test indicated that the catalytic activity increased with the increase in the substitution number(n) of tungsten atom in H3PMo12-nWnO40·xH2O and was constant as the substitution number(n) was more than 8.The catalytic activity increased with the increase in the catalyst loading and the selectivity of tetrahydrofuran was nearly 100%.

Application of NaHCO_3/ DTPA Extractant-ICP Spectrometry Technique in Soil Test for Availability of Nutrients and Heavy Metals

Soil test for availability of nutrients and heavy metals is extensively served as a means for the evaluations of soil fertility, and environmental effects and phytotoxicity of pollutants in soils, and for the fertilizer recommendation in agricultural and environmental sciences. Therefore, great attention has been paid to the measurement of elemental availability in soil test.

A Mechanistic Switch in C-H Bond Activation by Elusive Fe^(V)(O)(TAML)Reaction Intermediate:A Theoretical Study

The divergent behavior of C-H bond oxidations of aliphatic substrates compared to those of aromatic substrates shown in Gupta’s experiment was mechanistically studied herein by means of density functional theory calculations.Our calculations reveal that such difference is caused by different reaction mechanisms between two kinds of substrates(the aliphatic cyclohexane,2,3-dimethylbutane and the aromatic toluene,ethylbenzene and cumene).For the aliphatic substrates,C-H oxidation by the oxidant Fe^(V)(O)(TAML)is a hydrogen atom transfer process;whereas for the aromatic substrates,C-H oxidation is a proton-coupled electron transfer(PCET)process with a proton transfer character on the transition state,that is,a proton-coupled electron transfer process holding a proton transfer-like transition state(PCET(PT)).This difference is caused by the strongπ-πinteractions between the tetra-anionic TAML ring and the phenyl ring of the aromatic substrates,which has a“pull”effect to make the electron transfer from substrates to the Fe=O moiety inefficient.

Adsorption of Cd（II） on Zn-AI LDHs （Layered Double Hydroxides） Intercalated with Chelating Agents EDTA

The hydrotalcite-like compound [Zn2AI（OH）6]NO3-mH20 （shorted as ZnAI-NO3） was intercalated with the chelating agent EDTA （ethylene diamine tetraacetic acid） by anion exchange to uptake cadmium ion from aqueous solutions. The materials synthesized in this work were characterized by chemical analysis, FT-IR （fourier transform infrared spectroscopy）, XRD （X-ray powder diffraction） to confirm their properties. In order to investigate the optimum conditions for Cd（II） adsorption, the amount of Cd（ll） adsorbed by Zn-AI LDHs intercalated with EDTA （ZnAI-EDTA） under different conditions （i.e., adsorbent dosage, temperature and contact time） were determined by ICP-AES （inductively coupled plasma-atomic emission spectrometry）. Adsorption isotherms of Cd（II） onto ZnA1-EDTA were measured at varying initial Cd concentrations （0.05 mg/L to 1 mg/L） under optimized conditions. The data were applied to Langmuir and Freundlich isotherms model, and well fitted by the Freundlich isotherms model. The pseudo-second-order kinetic model was more adequate to describe the kinetic in this case.

Influence factors on activity of Ru–Zn catalysts in selective hydrogenation of benzene

Selective hydrogenation of benzene is an atom economic green route to produce cyclohexene. The control of Zn species is the key to the catalytic performance of Ru–Zn catalysts. The influences of ZnO crystals on selective hydrogenation of benzene were explored. A series of Ru–Zn catalysts with different Zn contents and ZnO morphologies were prepared by changing the amount of NaOH in the co-precipitation process. The catalysts were characterized by N_2 physisorption, X-ray powder diffraction(XRD), inductively coupled plasma optical emission spectrometer(ICP-OES), scanning electron microscope(SEM), temperature-programmed reduction(H_2-TPR)and Malvern laser particle size analyzer. It is found that with increasing the amount of NaOH, the Zn content first increased then decreased, and the ZnO crystals changed from relatively thicker pyramidal-shaped crystals to slimmer needle-shaped crystals. The catalyst had the highest Zn content(22.1%) and strongest interaction between ZnO crystals and Ru particles at pH 10.6 of the solution after reduction. As a result, it had the lowest activity. The activity of Ru–Zn catalysts is affected by both the Zn content and the interaction between ZnO crystals and Ru particles. The effect of reduction time was also investigated. Prolonging the reduction time caused no significant growth of ZnO crystals but the aggregation of catalyst particles and growth of Ru nanocrystals, thus resulting in the decrease of catalytic activity.

Promoting Effects of Pt on the Catalytic Performance of Supported NiB Amorphous Alloy Catalysts for Benzene Hydrogenation

A support(denoted AM) was prepared using pseudo-boehmite and mordenite.Ni-B and NiPtB amorphous catalysts were prepared on the support by the impregnation method followed by chemical reduction with a KBH4 solution.And the catalysts were characterized by X-ray diffraction(XRD),environment scanning electron microscope(ESEM),inductively coupled plasma(ICP),H2-temperature programmed reduction(H2-TPR),differential thermal analysis(DTA),and BET.Benzene hydrogenation was used as a probe reaction to evaluate the effect of addition of small quantities of Pt on the NiB/AM catalyst.The results show that Pt can promote the reduction of NiO and the formation of active sites,leading to smaller catalyst particles and better dispersion of active metal particles on the support.The catalytic activity,sulfur resistance and thermal stability were remarkably improved by Pt doping of the NiB/AM catalyst.