联合机组轧钢加热炉余热利用热力系统

介绍国内钢厂轧钢加热炉余热回收概况,在该系统的基础上,本着提高发电热效率,提出了容积式膨胀机-涡轮机联合机组热力系统,在原来系统基础上,提高余热蒸汽参数,进而提高了加热炉余热回收热效率,提高了余热蒸汽发电效率。     

电站锅炉烟气余热利用研究综述

电站锅炉的排烟温度一般设计在120~140℃,其携带出的热量损失占电站输入热量的3%~8%。合理设计烟气余热回收装置、充分利用电站锅炉排烟余热是提高电站效率的重要途径。本文介绍了烟气余热利用装置在电站系统中的应用,对烟气余热利用装置的布置形式和利用方式进行了阐述,综述了常规和新型烟气余热利用技术的现状和研究进展,并对其热力学原理以及研究方法进行了分析。结合吸收式溴化锂热泵技术,为进一步回收烟气余热的"量"与"质"提供新的方向。     

基于固体氧化物燃料电池的有机工质余热发电联合系统特性的理论研究

针对有机朗肯循环对低温余热回收的显著优势,提出了一种基于固体氧化物燃料电池(SOFC)的有机工质余热发电联合系统.该系统包含内重整SOFC、后燃室、燃气轮机、压气机、预热器和有机朗肯循环,实现了能量的梯级利用,有效地提高了系统的总发电效率.在稳态数学模型的基础上,建立了基于SOFC的有机工质余热发电联合系统的热力仿真分析平台,研究了关键参数对系统性能的影响.结果表明:在设计工况下,系统的总发电效率可达65%以上;随着燃料摩尔流量的增加,系统的净输出功增加,但系统的总发电效率有所下降;在一定范围内,增大压气机压比可以提高系统净输出功和总发电效率;随着蒸汽与碳物质的量比的增大,系统的净输出功减小,总发电效率下降.     

双热源集成发电系统研究

阐述了烧结工序中烧结机烟气和冷却机废气两种余热分布规律及协同回收利用原则,对立式逆流冷却机、热废气-烟气双热源余热锅炉装置、三进口余热锅炉装置及双余热源集成发电系统进行了研究,并以宝钢2号烧结余热回收系统余热源参数为基础,在烧结机烟气和冷却机废气携带热量不变的工况下,对研发的集成发电系统选定两种方案与原余热回收方案进行热经济性计算与对比分析.结果表明：双源集成发电系统两种方案的余热锅炉效率分别达到了73.4%和69.0%,发电净功率分别达到了16.40 MW和15.40 MW,研究结果可为中低品位余热高效回收装置的研发提供科学依据和技术支撑.     

有机朗肯循环系统回收低温余热的优势

当前国内传统余热发电系统都是利用水蒸气的朗肯循环。举例分析了目前我国低温余热回收状况,进而通过和传统水蒸气余热发电系统的对比,阐述了有机朗肯循环(ORC)在回收低温余热领域的优势以及国内外实际应用情况。最后提出了对于国内发展ORC余热发电系统的建议。     

烧结烟气暨高炉煤气综合利用发电技术

对于钢厂烧结余热和高炉煤气,目前国内普遍采用的是将二者各自回收用于发电;介绍了一种将烧结余热和富裕高炉煤气综合利用发电技术,并与目前国内普遍采用的发电技术进行了比较分析,体现了该余热回收综合利用发电技术的优越性,具有显著的经济效益和环保效益。     

基于AspenPlus的兆瓦级燃料电池分布式发电系统建模及仿真分析

  目的  燃料电池分布式发电技术是适应未来能源低碳化、清洁化、高效化发展趋势的重要应用方向。国内燃料电池电站项目较少,缺乏实际项目经验积累。为了推进燃料电池分布式电站技术的应用,文章概述了国内外应用现状,总结了高温燃料电池的优势与不足,调研了国内燃料电池建设应用案例,并建立了固体氧化物燃料电池与熔融碳酸盐燃料电池发电系统流程。  方法  经过文献调研与实地调研,确定了两种适合建设大型电站的燃料电池分布式发电技术,并利用AspenPlus化工模拟软件建立燃料电池系统流程模型、电化学模型和能量分析模型,并开展系统的性能仿真分析。  结果  分析结果与实际运行结果相吻合,分析预测的系统性能趋势与已有研究相一致。  结论  该仿真方法可用于兆瓦级高温燃料电池分布式发电系统的研究,可为扩大燃料电池应用规模提供数据支持。     

加热炉余热回收发电系统的选择和参数优化

针对目前加热炉生产过程中产生的2种热源,提出了3种余热回收发电系统,通过理论计算,得出基于能量梯级利用方式的组合式余热回收双压发电系统的发电效率最高,是非常理想的一种利用加热炉低温余热的方法,并分析该系统的高压段压力和低压段压力变化对于发电效率的影响,得出最佳的高压和低压参数。     

余热电站热力计算分析及装机方案确定

纯低温余热电站实际运行工况常偏离设计工况,且运行效率低,因此进行电站装机方案的研究具有现实意义.以武钢烧结环冷机测试的热废气温度和流量为基础,通过建立以最大发电净功率为决策变量的闪蒸系统热力计算模型,编制了 VB程序,并计算了武钢3台烧结环冷机余热集成回收的电站装机容量,与工程选型设计参数吻合,验证了此方法.其研究结果提高了烧结环冷机余热电站工程可行性研究决策的速度及准确性.     

基于9E燃气-蒸汽联合循环发电机组的烟气余热利用系统

基于燃气-蒸汽联合循环发电机组提出了回收余热锅炉尾部烟气余热对天然气进行加热的方案,提高了系统效率,同时大量回收了水资源,对于燃气-蒸汽联合循环发电系统的优化具有重要参考价值。以某容量为200 MW的9E燃气-蒸汽联合循环发电机组为例,对应用该方案下的系统流程、参数进行设计,对热经济性及水回收效益进行了计算,并与已有电加热和抽汽加热方案进行对比,结果表明：应用烟气余热回收加热天然气方案可有效回收烟气余热1.3 MW,水回收1.9 t/h,水回收率100%,余热锅炉效率提升0.57%,与电加热方案相比全年可节省453.6万元,与抽汽加热方案相比可节省273.6万元。     

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.     

沼气发电技术及沼气燃料电池在我国的应用状况与前景

沼气发电技术是一种清洁的发电技术。文章针对目前我国已有的沼气发电技术进行了技术评价,综述了这种技术的发展现状与近年来的应用情况;燃料电池也是一种新型高效、清洁的发电技术,文章对以沼气为燃料的燃料电池技术进行了介绍,对我国沼气利用技术的发展具有参考价值。     

Energy and exergy analyses of a combined ammonia-fed solid oxide fuel cell system for vehicular applications

In this study, both energetic and exergetic performances of a combined heat and power (CHP) system for vehicular applications are evaluated. This system proposes ammonia-fed solid oxide fuel cells based on proton conducting electrolyte (SOFC-H⁺) with a heat recovery option. Fuel consumption of combined fuel cell and energy storage system is investigated for several cases. The performance of the portable SOFC system is studied in a wide range of the cell’s average current densities and fuel utilization ratios. Considering a heat recovery option, the system exergy efficiency is calculated to be 60-90% as a function of current density, whereas energy efficiency varies between 60 and 40%, respectively. The largest exergy destructions take place in the SOFC stack, micro-turbine, and first heat exchanger. The entropy generation rate in the CHP system shows a 25% decrease for every 100 °C increase in average operating temperature.     

生物质燃料破碎机的开发

介绍了一种适用性广泛、效率高、能耗低的生物质燃料破碎技术。该技术与国外同类技术相比,综合破碎效率有所提高,综合吨料耗电量有所下降,购置费用降低70%,且维护方便。该技术的成功开发及应用,扩大了我国生物质发电燃料的利用范围,提高了生物质燃料破碎效率,降低了破碎作业成本,在生物质燃料供应方面有效地推动了我国生物质发电的技术进步。     

Simulation analysis of hydrogen recirculation rates of fuel cells and the efficiency of combined heat and power

The objective of this study was to simulate a proton-electrolyte membrane fuel cell (PEMFC) system, namely a PEMFC stack, an anode gas supply subsystem, an anode gas-recovery subsystem, a cathode gas supply subsystem, and a tail gas exhaustion subsystem. In addition, this paper presents an analysis of the efficiency of combined heat and power (CHP) systems. MATLAB and Simulink were employed for dynamic simulation and statistical analysis. The rates of active and the passive anode hydrogen recirculation were considered to elucidate the mechanism of hydrogen circulation. When recovery involved diverse recovery mechanisms, the recirculation rate was affected by the pressure at the hydrogen outlet of the PEMFC system. The greater the pressure was at that outlet, the higher the recovery rate was. In the hydrogen recovery system, when the temperature of the hydrogen supply end remained the same, increasing the temperature of the gas supply end increased the efficiency of the fuel cells; fixing the flow of the hydrogen supply end and increasing the temperature of the hydrogen supply end increased the efficiency of the PEMFC system. A calculation of the efficiency of the recovery system indicated that the thermal efficiency of the fuel cells exceeded 35%, the power generation efficiency exceeded 45%, and the efficiency of the CHP system exceeded 80%.     

高温燃料电池_燃气轮机混合发电系统性能分析

针对 高温燃料电池系统的高效率、环保性以及排气废热的巨大利用潜能,将其与燃气轮机组成混合装置进行发电是未来分布式发电的一种极有前景的方案。文中对高温燃料电池及混合循环系统作了简介,并对两种典型的高温燃料电池－燃气轮机混合循环发电系统进行了性能分析,这将为我国高温燃料电池－燃气轮机混合循环系统的研制提供参考。     

Thermodynamic analysis and assessment of an integrated hydrogen fuel cell system for ships

In this thermodynamic investigation, an integrated energy system based on hydrogen fuel is developed and studied energetically and exergetically. The liquefied hydrogen fueled solid oxide fuel cell (SOFC) based system is then integrated with a steam producing cycle to supply electricity and potable water to ships. The first heat recovery system, after the fuel cells provide thrust for the ship, is by means of a turbine while the second heat recovery system drives the ship's refrigeration cycle. This study includes energy and exergy performance evaluations of SOFC, refrigeration cycle and ship thrust engine systems. Furthermore, the effectiveness of SOFCs and a hydrogen fueled engine in reducing greenhouse gas emissions are assessed parametrically through a case study. The main propulsion, power generation from the solid oxide fuel cells, absorption chiller, and steam bottoming cycle systems together have the overall energy and exergy efficiencies of 41.53% and 37.13%, respectively.     

Parametric analysis of a hybrid power system using organic Rankine cycle to recover waste heat from proton exchange membrane fuel cell

Using fuel cell systems for distributed generation (DG) applications represents a meaningful candidate to conventional plants due to their high power density and the heat recovery potential during the electrochemical reaction. A hybrid power system consisting of a proton exchange membrane (PEM) fuel cell stack and an organic Rankine cycle (ORC) is proposed to utilize the waste heat generated from PEM fuel cell. The system performance is evaluated by the steady-state mathematical models and thermodynamic laws. Meanwhile, a parametric analysis is also carried out to investigate the effects of some key parameters on the system performance, including the fuel flow rate, PEM fuel cell operating pressure, turbine inlet pressure and turbine backpressure. Results show that the electrical efficiency of the hybrid system combined by PEM fuel cell stack and ORC can be improved by about 5% compared to that of the single PEM fuel cell stack without ORC, and it is also indicated that the high fuel flow rate can reduce the PEM fuel cell electrical efficiency and overall electrical efficiency. Moreover, with an increased fuel cell operating pressure, both PEM fuel cell electrical efficiency and overall electrical efficiency firstly increase, and then decrease. Turbine inlet pressure and backpressure also have effects on the performance of the hybrid power system.     

Fuel cell energy generation and recovery cycle analysis for residential application

Today’s concern regarding limited fossil fuel resources and their contribution to environmental pollution have changed the general trend to utilization of high efficiency power generation facilities like fuel cells. According to annual reducing capital cost of these utilities, their entrance to commercial level is completely expected. Hot exhaust gases of Solid Oxide Fuel Cells (SOFC) are potentially applicable in heat recovery systems. In the present research, a SOFC with the capacity of 215 kW has been combined with a recovery cycle for the sake of simultaneous of electric power, cooling load and domestic hot water demand of a hotel with 4600 m² area. This case study has been evaluated by energy and exergy analysis regarding exergy loss and second law efficiency in each component. The effect of fuel and air flow rate and also current density as controlling parameters of fuel cell performance have been studied and visual software for energy-exergy analysis and parametric study has been developed. At the end, an economic study of simultaneous energy generation and recovery cycle in comparison with common residential power and energy systems has been done. General results show that based on fuel lower heating value, the maximum efficiency of 83 percent for simultaneous energy generation and heat recovery cycle can be achieved. This efficiency is related to typical climate condition of July in the afternoon, while all the electrical energy, cooling load and 40 percent of hot water demand could be provided by this cycle. About 49 percent of input exergy can be efficiently recovered for energy requirements of building. Generator in absorption chiller and SOFC are the most destructive components of exergy in this system.     

固体氧化物燃料电池与燃气轮机联合发电系统模拟研究

固体氧化物燃料电池(SOFC)是一种高效低污染的新型能源。建立了以天然气为燃料的固体氧化物燃料电池和燃气轮机(GT)联合发电系统的计算模型,并对具体系统进行计算。结果表明：SOFC与GT组戍的联合发电系统,发电效率可达68％(LHV);加上利用的余热,整个系统的能量利用率可以超过80％。文中还分析了SOFC的工作压力、电流密度等参数对系统性能的影响,提高工作压力,可以增加电池发电量,提高系统的发电效率;而电流密度的增大将使SOFC及整个系统的发电量降低。