Proposal and Evaluation of a New‐Type Cogeneration System for Energy Saving and CO2 Emission Reduction

The paper proposes a cogeneration system which generates four types of energy or material resources: electricity, steam, hot water, and freshwater. The proposed system can capture CO₂, and be constructed on the basis of a combined cycle power generation system which consists of a gas turbine and a back‐pressure extraction turbine. In the proposed system, power is produced by driving the gas turbine system. High‐pressure saturated steam with medium temperature is produced in the heat recovery steam generator by using gas turbine exhaust gas, and then superheated with a regenerative superheater in which the fuel is burned by using oxygen instead of air for driving the steam turbine generator. Water and CO₂ are recovered from the flue gas of the regenerative superheater. It has been estimated that the proposed system has a net power generation efficiency of 41.2%, a heat generation efficiency of 41.5%, and a total efficiency of 82.7%. Freshwater of 1.34 t/h and CO₂ of 1.76 t/h can be recovered. It has also been shown, when a case study was set and evaluated, that the proposed system can save 31.3% of energy compared with the conventional energy supply system, and reduce CO₂ emission by 28.2% compared with the conventional cogeneration system. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

A CO2-recovering nonpolluting high-efficiency gas-turbine power-generation system utilizing saturated steam as its working gas

A carbon dioxide-recovering high-efficiency gas-turbine power-generation system is proposed in which carbon dioxide (CO₂) generated is recovered by adopting the oxygen (O₂) combustion method and no thermal nitrogen oxide is generated. In the system, saturated steam produced by utilizing waste heat is adopted as the working fluid of the gas turbine. Thus, the compressing process of the working fluid gas, which is the most energy-consuming process in generating power by using a gas turbine, is not needed. This makes the system extremely high efficient. By taking saturated steam of 210°C as an example, the characteristics of the system were simulated. The net exergetic efficiency of the system has been estimated to be 48.4 percent by considering both the exergy of the saturated steam and the electric power required not only to generate high-pressure oxygen, but also to liquefy the recovered CO₂. The value is higher than the exergetic efficiency 37.8 percent of large-scale thermal power generation plants using the same natural gas, and is 28.0 percent higher than its efficiency of 37.8 percent, the one estimated if the CO₂ generated is removed and recovered from the stack gas by using alkanolamine-based solvent and the recovered CO₂ is liquefied.     

Proposal and characteristics evaluation of a CO2-recovering hybrid power generation system utilizing solar thermal energy

A CO₂-recovering hybrid power generation system utilizing solar thermal energy is proposed. In the system, relatively low temperature saturated steam around 220°C is produced by using solar thermal energy and is utilized as the working fluid of a gas turbine in which generated CO₂ is recovered based on the oxygen combustion method. Hence, solar thermal utilization efficiency is considerably higher as compared with that of conventional solar thermal power plants in which superheated steam near 400°C must be produced for use as the working fluid of steam turbines; the requirement for solar radiation in the location in which the system is constructed can be significantly relaxed. The proposed system is a hybrid energy system using both the fossil fuel and solar thermal energy, thus the capacity factor of the system becomes very high. The fuel can be used exergetically in the system; i.e., it can be utilized for raising the temperature of the steam heated by utilizing the turbine exhaust gas more than 1000°C. The generated CO₂ can be recovered by using an oxygen combustion method, so that a high CO₂ capturing ratio of near 100 percent as well as no thermal NO_x emission characteristics can be attained. It has been shown through simulation study that the proposed system has a net power generation efficiency of 63.4 percent, which is higher than 45.7 percent as compared with that of the conventional power plant with 43.5 percent efficiency, when the amount of utilized solar energy is neglected and the temperature of the saturated steam is 220°C.     

Characteristics and economic evaluation of a CO2‐capturing solar thermal hybrid power generation system with heat storage

For wide use of a power plant utilizing solar energy, improvement of its economics is important. Both the economics and characteristics of a CO₂‐capturing solar thermal hybrid power generation system are evaluated in this paper. Since a relatively low temperature steam of 220 °C is produced by using solar thermal energy and is utilized as the working fluid of a gas turbine, the solar collector can attain high heat collecting efficiency. The net fuel‐to‐electricity conversion efficiency of the hybrid system is estimated to be higher than 60% on the lower‐heating‐value‐ basis. It has been estimated that the gross income and the period of depreciation of the proposed system are 34.8 × 10⁵ yen/year and 8.89 years, respectively, and that the system is economically feasible, under the assumptions of a solar collector area of 10 ha, a maximum net power output of 4 MW, and a heat storage capacity of 2000 m³. The amount of fuel saving and reduction of CO₂ emission of our system, compared to a conventional natural gas firing plant, are also estimated in the paper. © 1999 Scripta Technica, Electr Eng Jpn, 126(4): 21–29, 1999     

Characteristics evaluation of a CO2‐capturing power generation system with reheat cycle utilizing regenerative oxygen‐combustion steam‐superheater

A new CO₂‐capturing power generation system is proposed that can be easily realized by applying conventional technologies. In the proposed system, the temperature of medium‐pressure steam in a thermal power plant is raised by utilizing an oxygen‐combusting regenerative steam‐superheater. The CO₂ generated by combusting the fuel in the superheater can be easily separated and captured from the exhaust gas at the condenser outlet, and is liquefied. The superheated steam is used to drive a steam turbine power generation system. Using a high‐efficiency combined cycle power generation system as an example, it is shown that the proposed system can increase the power output by 10.8%, and decrease the CO₂ emissions of the entire integrated system by 18.6% with a power generation efficiency drop of 2.36% compared with the original power plant without CO₂ capture, when the superheated steam temperature is 750 ^°C. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 165(1): 35–41, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20575     

Coal-gas-burning high-efficiency power plant which recovers generated carbon dioxide

This paper describes the characteristics and construction of a coal-gas-burned high efficiency power plant which emits no carbon dioxide (CO₂) into the atmosphere. In a plant, CO₂ gas and superheated steam are used as the main and the secondary working fluids, respectively, of a closed dual fluid regenerative gas turbine power plant. Since coal gas composed of CO, H₂, CO₂ and CH₄ is burned in a combustor using oxygen, the exhaust gas let into a condenser includes only CO₂ and H₂O. Hence, CO₂ gas can be easily separated at the condenser outlet from condensate. In the plant, the combustion gas is first used to generate power by driving a turbine. High-temperature turbine exhaust gas is next utilized at a regenerator to heat the main working fluid of CO₂ gas flowing into the combustor, and then is utilized at a waste heat boiler to produce the superheated steam injected into the combustor. It is estimated that the power can be generated with gross thermal efficiency of 54.4 percent, and that the power generating efficiency is 46.7 percent. Generating efficiency is calculated by subtracting the power required for producing the high-pressure oxygen used for combustion from the generator output. It is shown that the estimated efficiency is higher by 18.1 percent than that of a conventional boiler steam turbine power generating plant into which a process for removing and recovering CO₂ from the stack gas by utilizing alkanolamine-based solvent is integrated.     

Construction and power generation characteristics of H2O turbine power generation system utilizing waste heat from factories

A new gas turbine power generation system has been proposed, in which the steam (H₂O) produced by utilizing waste heat from factories is used as the working fluid of gas turbine. A simulation model has been constructed to estimate power generation characteristics of the proposed system by adopting C++ language. It has been shown from simulation results that the proposed system has high exergetic efficiency, that is, the total exergetic efficiency is 46.3% and fuel‐based efficiency is 56.3% for a case where steam with a temperature of 275 °C produced from a garbage incineration plant is used. Sensitivity analysis has also been carried out when usable steam temperature and pressure is changed, together with the case when condenser outlet pressure is changed. Characteristics of a dual fluid gas turbine cycle power generation system (DFGT) have also been estimated in this study. It has been shown that the proposed system has 16.9% higher exergetic efficiency and 41.8% higher fuel‐base exergetic efficiency compared with DFGT. © 1999 Scripta Technica, Electr Eng Jpn, 130(1): 38–47, 2000     

整体煤气化联合循环系统变工况特性研究

采用ThermoFlex软件建立了200 MW级整体煤气化联合循环(integrated gasification combined cycle,IGCC)系统模型,从系统的角度出发计算研究了200 MW级IGCC系统的变工况特性。详细讨论了燃气轮机负荷、大气环境条件和整体空分系数对系统性能的影响。结果表明,燃气轮机采用压气机进口可转导叶角度调节–等燃气透平初温的调节方式降负荷时,燃气透平排气温度先增加后降低,而系统效率先缓慢降低后快速降低。随大气温度增加,燃气轮机功率、汽轮机功率和系统净功率均下降。在大气温度不变的条件下,大气压力对燃气轮机效率和系统净效率基本没有影响。增加整体空分系数可提高系统净效率,却使系统净功率降低。     

CO2 reduction effect of the utilization of waste heat and solar heat in a city gas system

We evaluated total energy consumption and CO₂ emissions in the phases of a city gas utilization system from obtaining raw materials to consuming the product. Assuming monthly and hourly demand figures for electricity, heat for space heating, and hot water in a typical hospital, we explore the optimal size and operation of a city gas system that minimizes the life cycle CO₂ emissions or total cost. The cost‐effectiveness of conventional cogeneration, a solar heating system, and hybrid cogeneration utilizing solar heat is compared. We formulate a problem of mixed integer programming that includes integral parameters that express the state of system devices such as the on/off condition of switches. As a result of optimization, the hybrid cogeneration can reduce annual CO₂ emissions by 43% compared with the system without cogeneration. The sensitivity of CO₂ reduction and cost to the scale of the CGS is also analyzed. © 2004 Wiley Periodicals, Inc. Electr Eng Jpn, 149(1): 22–32, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10369     

气电联合系统的双向优化调度

针对气电联合系统双向互联的发展需求,该文提出了含电转气和燃气轮机热电解耦的双向优化调度模型。在电至气与气至电两个方向,分别建立净效益最大电转气容量配置模型与考虑弃风成本、燃气轮机热电解耦的发电总成本最小模型,运用带权极小模函数和遗传算法对电转气设备净效益与系统发电总成本间的矛盾问题进行求解。研究结果表明电转气设备能够提高风电消纳能力并产生较高的净效益,热电解耦提高了燃气轮机发电的灵活性且减小了发电成本。     

注水运行对燃气轮机排气温度控制的影响

为了增加燃气轮机的出力和控制NOX的排放,增设了注水设备。机组注水运行后,通流部分的流量以及工质的热物理性能将发生变化,会对机组原来的温度控制系统及热通道部件的受热情况产生影响。介绍了燃机温度控制的原理,讨论了机组注水运行对温度控制的影响,尤其对注水后不同的温控基准与出力和寿命的关系进行了分析。     

燃气轮机全厂实时通信和监控系统的开发

介绍了闸北燃机电厂实时通信和监控系统的开发情况。该系统与美国GE公司的燃机M ark V控制系统进行通信,实现全厂多台机组的联网,并通过电厂局域网连接,远程实时监视机组运行数据。     

9F级燃气轮机主要控制系统分析

GE公司的9F级燃气轮机是目前国内新建联合循环机组中燃机的主力机型,其控制系统采用GE公司配套的新一代燃机控制系统MARKVI。对燃机的主要控制功能进行了分析和研究,包括转速/负荷控制系统、温度控制系统以及干式低NO燃烧控制系统等。可为今后燃机的调试、运行和维护提供参考。     

一种降低燃气轮机气耗的温度控制优化方法研究

燃气轮机的排气温度影响联合循环机组的整体效率,而排气温度的有效控制依赖于燃气轮机的温度控制策略。介绍了GE公司燃气轮机的温度控制设计原理及控制方法,依据不同类型的温度控制曲线的计算过程对其可优化的方法进行了分析研究。依托排气温度、经济性的需求,结合固有设备的性能,对温度控制策略中IGV温控线（TTRXGV）、压比温控线（TTRXP）、功率温控线（TTRXS）进行优化。结合优化后的机组证明燃气轮机发电气耗在折算成纯凝工况后较优化前降低了0.000 5 m³/（kW·h）,在满足燃气轮机安全稳定运行的前提下提升了其经济性,表明所述优化方法的有效性和可靠性。     

Proposal of a high‐performance solid oxide fuel cell combined power generation system with carbon dioxide recovery

A new fossil‐fuel‐utilized high‐performance combined power generation system with liquefaction recovery of carbon dioxide is proposed. In the system, pure oxygen is used as the oxidant gas to prevent the mixture of nitrogen in the exhaust gas and to make the liquefaction recovery of carbon dioxide possible. Solid oxide fuel cell is selected as the topping cycle. The exhaust fuel gas of the solid oxide fuel cell is afterburned with its exhaust oxidant gas of pure oxygen and the heat of the combustion gas is utilized in the bottoming cycle. Nonequilibrium MHD/noble gas turbine cycle is selected as the bottoming cycle because the temperature of the combustion gas reaches about 2300 K. It is made clear through detailed examination of energy balance that the total thermal efficiency of the system using natural gas (methane) as the fuel reaches 63.24% (HHV) or 70.18% (LHV). This efficiency is very high as for the system with carbon dioxide recovery. The proposed system, therefore, has excellent performance, and further research and development is warranted. © 2003 Wiley Periodicals, Inc. Electr Eng Jpn, 143(4): 12–21, 2003; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.10146     

燃机与锅炉耦合系统提高电厂供电效率的研究

为提高火力发电厂的供电效率,提出燃机与锅炉机组的耦合系统,并建立该耦合系统性能计算模型。经过对耦合系统性能的预测分析可知:排烟温度对系统的性能影响较大,在设定的130℃排烟温度条件下,耦合了燃机的电厂效率提高,供电煤耗降低。在一定的最高燃机工作温度条件下,进入锅炉机组总风量与流经燃机的空气流量与之间的比值有最佳值。以燃机最高工作温度700℃为例,耦合系统可以提高机组效率0.5%以上,其发出的功率可以增加电厂供电量超过4%,在考虑了机组热效率以及低温腐蚀等因素以后,除了抵消风机电耗以外,最佳的供电量增加幅度为1.64%,此时对应着最佳的锅炉机组总风量与流经燃机空气流量的比值,其大小为4.29。     

基于P2G与富氧燃烧联合运行的多能源低碳调度

电转气(power to gas,P2G)技术实现了电能与天然气的相互耦合,在提升多能源系统经济性和降低系统的碳排放方面发挥着重要作用。文中针对P2G过程中电解水产生的氧气未能被充分利用的问题,提出了基于P2G与富氧燃烧联合运行的多能源系统优化调度模型。首先,将P2G过程分为电转氢过程和甲烷化过程,电转氢过程产生的氧气输送给富氧燃烧电厂使用;再将富氧燃烧电厂捕集的CO₂与电转氢过程生成的氢气作为甲烷化反应的原料,生成的天然气供给燃气机组使用,从而实现资源的充分利用。其次,将P2G与富氧燃烧电厂联合运行模型引入多能源系统,构建了基于P2G与富氧燃烧电厂联合运行的低碳多能源系统架构。最后,建立以多能源系统运行成本最小为目标的低碳经济调度模型,并通过设置场景对比的方式进行验证。仿真结果表明,所提模型有效降低了系统成本及碳排放量。     

基于多智能体的海上油气平台风-燃协调频率辅助控制策略

为了提高含风电的远海油气平台电网的调频能力,基于多智能体一致性理论,提出了一种以双馈感应电机为单元的风电场与海上油气平台燃气透平机组的协调频率辅助控制方法。将远海孤立电网视为多智能体系统,将风电场与海上油气平台燃气透平机组看作智能体,基于海上电力网络的拓扑信息构建多智能体系统通信网络,实现各智能体之间的信息交互;分别建立风电场和海上油气平台燃气透平机组的频率辅助控制多智能体模型,基于多智能体一致性算法给出控制器结构,基于多智能体通信网络实现风电场智能体与海上油气平台燃气透平机组智能体之间的频率协调控制;通过线性二次型最优控制对控制器参数进行优化。基于算例仿真验证所提控制方法的有效性,结果表明所提协调频率辅助控制方法能有效提高系统的频率调节能力,抑制频率波动。     

V94.3A燃气轮机结构特点及安装实践

萧山发电厂的新建燃气轮机发电工程采用西门子公司生产的V94.3A型燃气轮机,其结构特点和安装流程与GE公司、三菱公司等设计的燃气轮机有所不同。结合安装实践阐述了西门子公司生产的燃气轮机安装过程中的重点和难点,并提出有效的措施。     

PG91E型燃气轮机的透平排气温度控制及燃烧监视

介绍了ＧＥ公司ＰＧ９１Ｅ型燃机的透平排气温度控制及燃烧监视的功能，基本原理和具体软件的实现，并介绍了有关机组在运行中出现的相关问题，提出了一些建议。