巨型水电站孤岛试验期间AVC电压波动的解决

本文首先分析国内典型的AVC的一般配置、控制策略和控制原理,针对巨型水电站孤岛试验期间的AVC控制的复杂工况进行阐述,对出现的AVC电压波动的情况进行分析,并对采用的解决方案进行介绍,为今后类似电站的孤岛运行期间的AVC电压控制提供一些参考建议。     

Increased Uptake of Chelated Copper Ions by Lolium perenne Attributed to Amplified Membrane and Endodermal Damage

The contributions of mechanisms by which chelators influence metal translocation to plant shoot tissues are analyzed using a combination of numerical modelling and physical experiments. The model distinguishes between apoplastic and symplastic pathways of water and solute movement. It also includes the barrier effects of the endodermis and plasma membrane. Simulations are used to assess transport pathways for free and chelated metals, identifying mechanisms involved in chelate-enhanced phytoextraction. Hypothesized transport mechanisms and parameters specific to amendment treatments are estimated, with simulated results compared to experimental data. Parameter values for each amendment treatment are estimated based on literature and experimental values, and used for model calibration and simulation of amendment influences on solute transport pathways and mechanisms. Modeling indicates that chelation alters the pathways for Cu transport. For free ions, Cu transport to leaf tissue can be described using purely apoplastic or transcellular pathways. For strong chelators (ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA)), transport by the purely apoplastic pathway is insufficient to represent measured Cu transport to leaf tissue. Consistent with experimental observations, increased membrane permeability is required for simulating translocation in EDTA and DTPA treatments. Increasing the membrane permeability is key to enhancing phytoextraction efficiency.     

Microwave assisted water extraction of plant compounds

The development of environmentally friendly processes with limited generation of polluting streams to attain sustainable utilization of raw materials is encouraged. The implementation of novel extraction technologies more efficient, selective and with lower energy consumption than conventional ones, can help in achieving this objective. Particularly promising are aqueous based methods, since water is a cheap, safe and abundant solvent and the limited use of toxic organic solvents is a consumer's, ecological and processing demand. The benefits and the limiting aspects of microwave assisted water extraction, either adding water as the only solvent or in solvent free processes, using the naturally present water in vegetal materials for the extraction of valuable components from renewable vegetal sources are highlighted and the potential of this technique for industrial applications is discussed. © 2014 Society of Chemical Industry     

核电厂聚乙烯管道设计方法及标准简介

随着聚乙烯管道在三门核电厂、大亚湾核电厂中的试应用成功，大量的新建核电厂及核电厂改造项目均将聚乙烯管道作为海水冷却水管道系统的首选管材，自主研制核电厂聚乙烯管技术标准迫在眉睫。本文介绍了核电聚乙烯管道的发展历史和应用现状，对比了核安全3级聚乙烯管道和非核安全相关聚乙烯管道、城市燃气与给水聚乙烯管道技术标准的设计方法及适用范围，探讨了中国目前聚乙烯管技术标准与核3级聚乙烯管道技术标准的差异与差距，为核电厂聚乙烯管道的设计制造与标准研制提供参考。     

热电厂供电运行故障及应对措施探讨

长期高负荷、高输出的热电厂供电运作过程中不可避免地出现设备磨损等故障。为了做好供电运行中的故障预防以及有效维护,开展了热电厂供电运行故障及应对措施探讨。分析了造成设备磨损、备用电源失效、发电设备电压不稳定、电力接地短路、发电设备温度过高等故障原因,并提出了有针对性的解决方法,以保障热电厂供电系统的正常运转。分析认为,遇到不同的电力故障问题,应具体分析、区别对待,并在检修的过程中及时总结经验;对于设备本身的问题,应最大程度以技术创新弥补自身结构缺陷。     

焦化厂电气设备常见故障及诊断

焦化厂电气设备更新迅速、功能多样,设备结构和功能趋于复杂化,对故障诊断的精准性提出了更高要求。为保障焦化厂电气设备的正常运行,对电气设备常见故障及影响因素展开分析,探讨了电气设备故障诊断的作用和方法,并对设备维护的要点进行了论述。分析认为,电气设备运行时受诸多因素影响,为保证设备正常使用、延长使用年限,需要以理论为指导,科学制定检修计划,结合设备实际情况合理应用诊断技术。     

Development and field test of the articulated mobile robot T2 Snake-4 for plant disaster prevention

Abstract

In this work, we develop an articulated mobile robot that can move in narrow spaces, climb stairs, gather information, and operate valves for plant disaster prevention. The robot can adopt a tall position using a folding arm and gather information using sensors mounted on the arm. In addition, this paper presents a stair climbing method using a single backward wave. This method enables the robot to climb stairs that have a short tread. The developed robot system is tested in a field test at the World Robot Summit 2018, and the lessons learned in the field test are discussed.     

Electromagnetic transients in the control system of output parameters of a solar power plant in Tajikistan Central Asia region

At present, as the demand for electricity increases in all sectors, there is an urgent need to introduce alternative renewable energy sources into modern energy systems. Renewable energy sources, which consist of solar (photovoltaic, PV), wind and hydro power, are key alternative sources of “green energy’’ energies, but it can also be used to produce “green” hydrogen. Thanks to scientific and technological progress, the cost of photovoltaic solar radiation converters is constantly decreasing at a high rate, which makes it possible to build solar power plants of sufficiently large capacity. In the coming decades, solar energy will become an incentive for the economic development of countries that have the maximum “solar” resource. The Republic of Tajikistan is one of these countries with a high potential for solar energy.The article presents an analysis of the resources and potential of solar energy in the Republic of Tajikistan. The study of electromagnetic transients in networks with photovoltaic solar power plants is performed. The main equations, simulation model and calculations of transients are presented, taking into account changes in voltage on DC buses. An algorithm for controlling the system of automatic control of output parameters is proposed. The analysis of dynamic and static modes in parallel operation of a solar power plant with the grid is carried out. A block diagram and computer model is constructed in the MATLAB package together with Simulink and Power System Blockset.     

Efficient utilization of waste heat from molten carbonate fuel cell in parabolic trough power plant for electricity and hydrogen coproduction

Direct steam generating parabolic trough power plant is an important technology to match future electric energy demand. One of the problems related to its emergence is energy storage. Solar-to-hydrogen is a promising technology for solar energy storage. Electrolysis is among the most processes of hydrogen production recently investigated. High temperature steam electrolysis is a clean process to efficiently produce hydrogen. In this paper, steam electrolysis process using solar energy is used to produce hydrogen. A heat recovery steam generator generates high temperature steam thanks to the molten carbonate fuel cell's waste heat. The analytical study investigates the energy efficiency of solar power plant, molten carbonate fuel cell and electrolyser. The impact of waste heat utilization on electricity and hydrogen generation is analysed. The results of calculations done with MATLAB software show that fuel cell produces 7.73 MWth of thermal energy at design conditions. 73.37 tonnes of hydrogen and 14.26 GWh of electricity are yearly produced. The annual energy efficiency of electrolyser is 70% while the annual mean electric efficiency of solar power plant is 18.30%.The proposed configuration based on the yearly electricity production and hydrogen generation has presented a good performance.     

Dynamic energy and mass balance model for an industrial alkaline water electrolyzer plant process

This paper proposes a parameter adjustable dynamic mass and energy balance simulation model for an industrial alkaline water electrolyzer plant that enables cost and energy efficiency optimization by means of system dimensioning and control. Thus, the simulation model is based on mathematical models and white box coding, and it uses a practicable number of fixed parameters. Zero-dimensional energy and mass balances of each unit operation of a 3 MW, and 16 bar plant process were solved in MATLAB functions connected via a Simulink environment. Verification of the model was accomplished using an analogous industrial plant of the same power and pressure range having the same operational systems design. The electrochemical, mass flow and thermal behavior of the simulation and the industrial plant were compared to ascertain the accuracy of the model and to enable modification and detailed representation of real case scenarios so that the model is suitable for use in future plant optimization studies. The thermal model dynamically predicted the real case with 98.7 % accuracy. Shunt currents were the main contributor to relative low Faraday efficiency of 86 % at nominal load and steady-state operation and heat loss to ambient from stack was only 2.6 % of the total power loss.