质子交换膜燃料电池模拟器的建模与控制

燃料电池是极具吸引力的新能源之一,但它在化学反应中存在极化现象,输出特性不稳定.搭建了一种质子交换膜燃料电池的仿真器,用于在无实际燃料电池的情况下取代燃料电池,进行相关的优化控制实验.实验表明,该仿真器的输出特性与实际燃料电池的输出特性非常逼近.用其取代燃料电池进行优化控制实验是可行的,为进行燃料电池供电系统的能量管理、控制和优化提供了有利帮助.     

燃煤火电厂年度燃料成本最小化决策模型及应用

燃料成本占火力发电厂生产成本的60%~70%,燃料成本管理直接影响电厂经济效益。目前,中国燃煤火电厂十分重视燃料成本的全过程管理。综合考虑燃料采购成本、库存成本、损耗成本之间的相互关系,建立了电厂年度燃料成本最小化决策模型。以某电厂2019年实际生产经营数据进行计算与决策。结果表明：利用模型决策采购时间点及采购量降低了年度燃料总成本约1.18%、年度燃料采购成本约1.14%、年度燃料库存和损耗成本约1.43%,为燃煤电厂燃料成本的科学管理提供了新方法。     

Group search optimization for economic fuel scheduling

The economical use of fuel available for the generation of power has become a major concern of electric utilities. This paper presents an approach for economic fuel scheduling problem by using group search optimization. This is a minimization technique that includes the standard load constraints as well as the fuel constraints. The generation schedule is compared to that which would result if fuel constraints were ignored. The comparison shows that fuel consumed can be adequately controlled by adjusting the power output of various generating units so that the power system operates within its fuel limitations and within contractual constraints. It has been found that small additional amount of fuel may be required to serve the same power demand but the additional cost of this fuel may well compensate for the penalty that might otherwise be imposed for not maintaining the fuel contract. Numerical results for two test systems have been presented and the test results obtained from group search optimization are compared with those obtained from particle swarm optimization and evolutionary programming.     

Adaptive fuel allocation using pseudo fuel prices

The authors outline a practical adaptive fuel allocation approach. The approach uses pseudo fuel prices as decision variables. As a result, the fuel allocation decision can be conveniently implemented in system operation by using the pseudo fuel prices to dispatch generation. A lower pseudo price usually results in higher fuel consumption and a higher pseudo price usually results in lower fuel consumption. In the proposed approach, the systematic criterion for adaptively identifying the need for reschedulings is based on the absolute change in each pseudo fuel price. Various aspects of the proposed approach are discussed, and its application to a midwestern utility system is illustrated     

Heating Fuel Oil and Other Fluids in Cement Plants

The current fuel market situation is causing more cement plants to look toward fuel oil as either a primary or as a secondary fuel. This paper discusses the various ``direct' and ``indirect' heating methods available for heating industrial fluids as related to heating fuel oil. The basic fuel oil heating system is illustrated, and the various methods and equipment for heating at the storage, pumping, pipeline, and booster stages are discussed.     

Fuel Efficiency of Energy Sources in Heat Supply Systems

The imperfection of the approach to the fuel efficiency assessment of energy sources with the combined generation of electrical and thermal energy based on the specific fuel consumptions is shown; it is caused by the fact that the use of different methods for the separation of the total fuel consumption leads to ambiguous results. A simple and feasible technique for the comparative assessment of the system fuel efficiency of existing energy sources of different types is proposed. The technique is based on the combined use of two dimensionless criteria that are calculated based on the CHPP production activity parameters provided in the yearly reports. These criteria have a clear physical sense and do not require the separation of the CHPP total fuel expenses into components. Analytical calculation dependences that relate the values of the proposed criteria and the actual relative fuel conservation, which is calculated for each individual energy source with respect to the average fuel efficiency level that is actually achieved in the considered energy system, are presented. The proposed approach and the technique based on it make it possible to objectively assess and compare the actual fuel efficiencies of energy sources of different types in terms of relative fuel conservation. The practical importance of the developed technique is demonstrated for a specific case: the comparative analysis of the actual fuel efficiency at all heat supply sources of the Saratov Branch of PAO T Plus is performed based on the available reported data on the results of the production activity. The results are visualized in the form of a diagram representing the actual fuel efficiency of each CHPP (for each year) with respect to the average level achieved in this energy system during the operating period of 8 years. The presented materials can serve as a basis for the choice of rational ways to improve the CHPP fuel efficiency.     

Fuel constrained economic emission load dispatch using hopfield neural networks

This paper presents a new approach using Hopfield neural networks for solving fuel constrained economic emission load dispatch problems of thermal generating units. This is a multi-objective minimization technique that includes the standard load constraints as well as the fuel constraints. The generation schedule is compared to that which would result if fuel constraints were ignored. The comparison shows that fuel consumed can be adequately controlled by adjusting the power output of various generating units so that the power system operates within its fuel limitations and within contractual constraints. It has been found that one of the two objective functions (fuel cost and emission level) may be increased while other may be decreased to serve the same power demand but this may well compensate for the penalty that might be otherwise imposed for not maintaining the fuel contract. Numerical results for an example system have been presented to illustrate the performance and applicability of the proposed method.     

Ways of solving environmental problems while transferring the boilers for burning water-bitumen mixture instead of fuel oil

Information concerning a new kind (for Russia) of liquid fuel, i.e., water-bitumen mixture (orimulsion), is presented. The application of the new fuel instead of the fuel oil at a boiler of a power unit of 350-MW capacity makes it possible to decrease sufficiently the expenditures for fuel while keeping the main environmental indices.     

Performance of several types of fuel cells and factor analysis of performance

There are four types of fuel cells: Polymer Electrolyte Fuel Cells (PEFC), Phosphoric Acid Fuel Cells (PAFC), Molten Carbonate Fuel Cells (MCFC), and Solid Oxide Fuel Cells (SOFC). The performance of these fuel cells has not been compared. Equations that are able to express the performance of these fuel cells accurately were derived or modified from the latest published performance data. The cell voltages of the four fuel cells were estimated by these equations, resulting in high‐temperature fuel cells such as MCFC and SOFC having higher energy conversion efficiencies than low‐temperature fuel cells such as PEFC and PAFC. This difference originates from low cathode polarization, overcoming both a decrease of open circuit voltage with increasing temperature and higher Nernst losses for high‐temperature fuel cells of approximately 85 mV than those for low‐temperature fuel cells due to steam generation in the anode chamber in the high‐temperature fuel cells. A generalized relationship between cell voltage and operating temperature was derived, stating that the cell voltage is almost constant between 500 °C and 1000 °C. A fuel cell which has protons as a migration species in the electrolyte and works between 250 °C and 500 °C would give a performance comparable with high‐temperature fuel cells due to lower Nernst losses than those for high‐temperature fuel cells. © 2001 Scripta Technica, Electr Eng Jpn, 138(1): 24–33, 2002     

基于神经网络法燃油泵驱动电机转速匹配研究

航空燃油泵驱动电机负责给燃油泵提供所需的动力。由于燃油驱动电机与燃油泵之间存在很强的非线性及耦合性,使得燃油泵无法正常运行在工况点,造成严重的能量损耗。针对该问题,提出了利用Legendre神经网络法来解决燃油泵与驱动电机转速匹配问题。首先,利用Legendre神经网络法拟合出燃油泵的特性曲线,然后再利用该方法建立以燃油泵的流量、扬程为输入,驱动电机转速为输出的神经网络模型。燃油泵与驱动电机转速匹配仿真结果表明,相比于传统的最小二乘法,Legendre神经网络法具有更高的精度。     

电动汽车用氢燃料电池发展综述

氢燃料电池是一种将燃料(和氧化剂)的化学能连续地转化为电能的装置。氢燃料电池以化学方式实现能量转换,不受热发动机卡诺循环的限制,具有较高的转换效率。氢燃料电池在全球大范围环保发展下已成为最清洁环保的电动汽车用电池。介绍了氢燃料电池的发展历程、工作原理、优缺点以及氢燃料电池电动汽车的应用实例,展望其发展前景。     

生物质燃料气的燃气热力性质计算方法和程序

生物质能是一种可再生、对环境友好和利用过程中二氧化碳零排放的能源资源, 所以研究生物质气化发电技术意义重大。在烧生物质燃料气的燃气轮机性能计算中, 需要使用生物质燃料气的燃气热力性质数据, 如果将其比热视为常数或采用平均比热都会引起较大误差, 因此需要基于变比热的生物质燃料气的燃气热力性质计算方法。生物质燃料气属于含有不可燃成分的混合气体燃料, 因而将基于变比热的混合气体燃料(含不可燃成分)燃气热力性质的计算方法应用于变比热的生物质燃料气的燃气热力性质计算, 并且用Delphi6 0开发了计算程序。通过对烧某一生物质燃料气的LM2500型燃气轮机的某一工况点热力性能计算, 对该计算方法和程序进行了验证。结果表明, 混合气体燃料(含不可燃成分) 燃气热力性质的计算方法可以应用于生物质燃料气的燃气热力性质计算, 编制的计算程序为烧生物质燃料气的燃气轮机性能计算提供了解决方案。     

Improvement of anode oxidation reaction of a fuel cell using ammonium formate with Pt‐Ir catalysis

We have attempted to develop high‐performance and safe fuel cells by using ammonium formate as a solid (powder) fuel. This solid fuel has the potential of safer transportability than liquid fuels such as methanol from the viewpoint of toxicity and flammability. In order to make use of some of the advantages of ammonium formate, we investigated the oxidation characteristics of ammonium formate with respect to a Pt electrode. Cyclic voltammograms indicate that ammonium formate has high oxidation activity with respect to a Pt electrode. We have also found that the oxidation of ammonium formate can be improved by the addition of Ir to Pt catalysts. It is highly likely that ammonium formate will be useful as a solid (powder) fuel for polymer electrolyte membrane (PEM) fuel cells. This new fuel will promote the development of safe fuel cells for PEM. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(4): 45–50, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21043     

家用混合发电系统的能量优化控制策略

家庭负载频繁出现瞬间的峰值功率需求,由燃料电池/蓄电池组成的混合发电系统是最清洁和高效的发电方式之一.燃料电池仅满足基本负载,由蓄电池放电以满足瞬间的峰值功率需求.研究了一个60 kW家用混合发电系统,该系统由质子交换膜燃料电池(PEMFC)和阀控铅酸蓄电池组成,设计为10个家庭同时供电.在保证系统可靠性和持久性的同时,为了提高整个混合发电系统的工作效率和燃料经济性,在系统仿真和分析的基础上详细描述了一种基于规则的能量优化控制策略.仿真实验结果表明,与燃料电池单独供电相比,60 kW混合发电系统通过优化2种能源之间的功率分配,能够在响应负载的同时提高整个发电系统的工作效率和燃料经济性.     

基于不同电极位置的PEMFC运行特性研究

质子交换膜燃料电池(PEMFC)是一种有巨大发展潜力的发电装置,特别适合成为新一代便携式电源和电动汽车的动力源。水是影响燃料电池性能的关键因素,良好的水管理是使其安全稳定运行和提高其性能的必要条件。在PEM燃料电池的阴极侧安装风扇,向燃料电池提供氧化剂和降低电池温度,通过实验,观察到在电池堆方向发生变化的情况下,PEM燃料电池性能及其内部传质情况会发生明显变化。实验结果发现:当电流密度较小时,电极方向对PEM燃料电池的性能影响不明显;当电流密度较大时,阳极在上、阴极在下时燃料电池性能优于阴极在上、阳极在下的燃料电池性能。     

Modeling and model predictive control of the BioPower combined heat and power (CHP) plant

This paper presents a model predictive control (MPC) strategy for BioGrate boiler, compensating the main disturbances caused by variations in fuel quality such as the moisture content of fuel, and variations in fuel flow. The MPC utilizes models, the fuel moisture soft-sensor to estimate water evaporation, and the fuel flow calculations to estimate the thermal decomposition of dry fuel, to handle these variations, the inherent large time constants, and long time delays of the boiler. The MPC strategy is compared with the method currently used in the BioPower 5 CHP plant. Finally, the results are presented, analyzed and discussed.     

Studying the vibration and random hydrodynamic loads on the fuel rods bundles in the fuel assemblies of the reactor installations used at nuclear power stations equipped with VVER reactors

Random hydrodynamic loads causing vibration of fuel rod bundles in a turbulent flow of coolant are obtained from the results of pressure pulsation measurements carried out over the perimeter of the external row of fuel rods in the bundle of a full-scale mockup of a fuel assembly used in a second-generation VVER-440 reactor. It is shown that the turbulent flow structure is a factor determining the parameters of random hydrodynamic loads and the vibration of fuel rod bundles excited by these loads. The results from a calculation of random hydrodynamic loads are used for estimating the vibration levels of fuel rod bundles used in prospective designs of fuel assemblies for VVER reactors.     

少油点火油燃烧器雾化及燃烧特性

为研究少油点火油燃烧器的雾化特性,利用Fluent软件构建油枪喷嘴的三维计算模型,模拟计算不同燃油质量流量下的燃油雾化速度,得出喷嘴出口雾化速度不受燃油质量流量影响的结果。为研究少油点火油燃烧器的燃烧特性,建立油燃烧器三维计算模型,对模拟计算得到的油燃烧室温度和速度分布情况进行分析,得出燃油质量流量越大,燃烧温度和速度越高的结果。分析结果表明:油火焰的温度水平能点燃煤粉,且油耗低。     

Current state of nuclear fuel cycles in nuclear engineering and trends in their development according to the environmental safety requirements

The state and trends in the development of nuclear fuel cycles in nuclear engineering, taking into account the ecological aspects of using nuclear power plants, are considered. An analysis of advantages and disadvantages of nuclear engineering, compared with thermal engineering based on organic fuel types, was carried out. Spent nuclear fuel (SNF) reprocessing is an important task in the nuclear industry, since fuel unloaded from modern reactors of any type contains a large amount of radioactive elements that are harmful to the environment. On the other hand, the newly generated isotopes of uranium and plutonium should be reused to fabricate new nuclear fuel. The spent nuclear fuel also includes other types of fission products. Conditions for SNF handling are determined by ecological and economic factors. When choosing a certain handling method, one should assess these factors at all stages of its implementation. There are two main methods of SNF handling: open nuclear fuel cycle, with spent nuclear fuel assemblies (NFAs) that are held in storage facilities with their consequent disposal, and closed nuclear fuel cycle, with separation of uranium and plutonium, their purification from fission products, and use for producing new fuel batches. The development of effective closed fuel cycles using mixed uranium–plutonium fuel can provide a successful development of the nuclear industry only under the conditions of implementation of novel effective technological treatment processes that meet strict requirements of environmental safety and reliability of process equipment being applied. The diversity of technological processes is determined by different types of NFA devices and construction materials being used, as well as by the composition that depends on nuclear fuel components and operational conditions for assemblies in the nuclear power reactor. This work provides an overview of technological processes of SNF treatment and methods of handling of nuclear fuel assemblies. Based on analysis of modern engineering solutions on SNF regeneration, it has been concluded that new reprocessing technologies should meet the ecological safety requirements, provide a more extensive use of the resource base of nuclear engineering, allow the production of valuable and trace elements on an industrial scale, and decrease radioactive waste release.     

日本燃料电池的发展状况

简要地概述了日本燃料电池的发展状况。因燃料电池两电极中均含有贵重金属 (铂 钌 )作催化剂 ,大部分情况需要防止其对一氧化碳的中毒失效。如果含有碱性电解质 ,要考虑除去二氧化碳。碱性燃料电池开发较早 ;高分子电解质燃料电池在家庭及动力电源的应用上取得很大进展 ;磷酸型燃料电池已广泛应用于供电、供热 ;熔融碳酸型燃料电池则非常适合于大规模及高效率的电站应用 ;固体氧化物燃料电池的重点集中于平面基材的研究 ,以降低成本 ,适合大规模生产。在各种燃料电池的研究开发上 ,不单只是利用燃料来发电 ;更重要的是使能源得到合理的充分利用。通过对上述五种燃料电池的性能比较 ,分析了它们今后的发展方向