中小型梯级泵站联合调度运行方法设计

中小型梯级泵站在不同工况下运行时,传统调度方法需调度运行的水泵数量过多,导致消耗的电功率过大。为此,从减少功耗的角度出发,本研究设计了新的中小型梯级泵站联合调度运行方法。首先,变角调节泵站水泵驱动叶片,然后利用PID控制器控制水泵流量,在此基础上,引入一个变量将泵站建模与编程计算过程分解为多个子梯级,从而得到一个联合调度运行模型,选定一个合适的调控参数形成调度运行递接结构,从而实现对泵站的联合调度运行。实验结果表明:与传统调度运行方法相比,本文方法能够在满足泵站供水需求的同时,更大程度地减少需调度运行的水泵数量,消耗的电功率数值为893.7 kW,明显少于传统方法,充分证明了本文方法的有效性。

Correlation between H-ZSM-5 crystal size and catalytic performance in the methanol-to-aromatics reaction

The porosity of H‐ZSM‐5zeolite is known to facilitate the diffusion of molecules in the methanol‐to‐aromatics(MTA)reaction.The activity and selectivity of the H‐ZSM‐5catalyst in the MTAreaction has been studied as a function of crystal size.ZSM‐5zeolites with different crystal sizeswere successfully synthesized by conventional hydrothermal methods.Tailoring ZSM‐5particle sizewas easily controlled by changes to the sol‐gel composition,and in particular,the deionized waterto tetrapropylammonium hydroxide ratio,and crystallization time.The structure of the H‐ZSM‐5zeolites were characterized by X‐ray diffraction and the morphology of the zeolite particles wasdetermined by scanning electron microscopy.N2adsorption‐desorption measurements establishedchanges to the textural properties,and compositional properties were characterized by X‐ray fluorescencespectroscopy.Acidity measurements of the catalysts were measured by pyridine‐adsorbedFourier transform infrared spectroscopy and the temperature‐programmed desorption of ammonia.After subjecting the catalysts to the MTA reaction,the total amount of coke formed on the spentdeactivated catalysts was determined by thermal gravimetric analysis.The results show that theSiO2/Al2O3molar ratios and acidic properties of the H‐ZSM‐5samples are similar,however,thenano‐sized hierarchical ZSM‐5zeolite with an additional level of auxiliary pores possesses a higher

Debris flow susceptibility analysis based on the combined impacts of antecedent earthquakes and droughts： a case study for cascade hydropower stations in the upper Yangtze River, China

The upper Yangtze River region is one of the most frequent debris flow areas in China. The study area contains a cascade of six large hydropower stations located along the river with total capacity of more than 70 million kilowatts. The purpose of the study was to determine potential and dynamic differences in debris flow susceptibility and intensity with regard to seasonal monsoon events. We analyzed this region's debris flow history by examining the effective peak acceleration of antecedent earthquakes,the impacts of antecedent droughts, the combined effects of earthquakes and droughts, with regard to topography, precipitation, and loose solid material conditions. Based on these factors, we developed a debris flow susceptibility map. Results indicate that the entire debris flow susceptibility area is 167,500 km^2, of which 26,800 km^2 falls within the high susceptibility area, with 60,900 km^2 in medium and 79,800 km^2 are in low susceptibility areas. Three of the six large hydropower stations are located within the areas with high risk of debris flows. The synthetic zonation map of debris flow susceptibility for the study area corresponds with both the investigation data and actual distribution of debris flows. The results of debris flow susceptibility provide base-line data for mitigating, assessing, controlling and monitoring of debris flows hazards.