余热锅炉汽水系统动态数学模型及仿真

运用序贯模块法,建立了余热锅炉基本部件比较精细的通用模型及描述各个模块之间联系的系统结构模型。并对某一余热锅炉的动态特性进行仿真,对仿真结果进行了分析,有助于判断汽水侧动态过程对余热锅炉的影响。     

余热锅炉动态特性的数值计算

本文对单压余热锅炉的动态特性进行了数值计算。分析了当燃气轮机排烟温度和流量发生扰动时,余热锅炉出口参数随时间的变化规律。研究结果为联合循环余热锅炉控制系统的设计提供了理论依据。     

余热锅炉启动特性仿真研究

在余热锅炉运行中,启动——特别是冷态启动最难调控也最容易出现故障,同时启动操作的优劣也严重影响机组的效率及寿命,因此有必要对余热锅炉的启动特性进行分析。本文依据理论分析和经验归纳相结合方法,建立余热锅炉数学模型,对高压过热器和高压省煤器模块,高压蒸发器和低压蒸发器模块,高压汽包和除氧器模块的计算方法进行详细的研究。利用仿真软件,对余热锅炉冷态启动过程进行了模拟,结果准确,证实了该软件不仅能模拟余热锅炉的稳态运行工况,更能够模拟冷态启动等负荷大范围变动时的动态特性,具有一定可行性和可靠性,能够满足实时仿真的需要。     

基于APROS的联合循环机组余热锅炉仿真模型

针对某电厂开发仿真培训系统中余热锅炉子系统模型,根据余热锅炉的工作原理及特性,以质量、动量、能量守恒方程为基础,采用模块化建模的思路,建立了基于APROS的联合循环机组余热锅炉仿真模型。仿真实验表明:建立的模型能够正确的反映出余热锅炉汽水侧换热及流动特性,模型具有很高的静态精度及良好的现场适应性,能够满足实时仿真的需要,可作为联合循环机组仿真培训系统中重要的子系统,对于联合循环机组性能分析、运行优化、故障诊断等方面研究也有很大的帮助。     

M701F联合循环机组余热锅炉启动过程优化研究

针对三菱M701F级燃气-蒸汽联合循环机组经常参与调峰而涉及到频繁启停,且余热锅炉因惯性大而启动慢的特点,结合余热锅炉的工作原理及相关特性 ,为了缩短余热锅炉启动时间,提出了一种启动优化模型。该方法以APROS(Advanced Process Simulation Software)模型为基础,综合理论分析和经验归纳,对余热锅炉内部各模块进行了详细的仿真研究。仿真结果表明,以APROS为基础的优化模型能够在准确模拟余热锅炉稳态运行工况的同时缩短至少20%的启动时间,对联合循环机组整体的运行优化有很大的帮助。     

余热锅炉动态数学模型建立及仿真

采用集总参数法建立了余热锅炉动态模型。根据余热锅炉的工作原理和特性,以能量和质量守恒原理为基础,详细论述了其内部蒸发器系统和单相介质换热器的数学模型算法,简化了汽水系统结建模仿真的复杂度。仿真结果表明该模型具有较好的动态响应特性,且模型运行稳定。     

超临界直流锅炉长期动态特性的建模与仿真

超临界直流锅炉长期动态特性对超临界直流锅炉汽轮机发电机组的仿真和控制系统设计具有十分重要的意义。为了快捷、全面、可靠地研究调峰及负荷变化过程中超临界直流锅炉的长期动态特性，通过合理地机理分析和模型简化，应用状态空间方法建立了超临界直流锅炉省煤器，水冷壁，过热器及再热器的简化数学模型，推导出工质侧压力流量变化的一组更为简洁、新颖的非线性关系式。最后以上述简化状态空间模型和非线性关系式为工具对某600MW超临界直流锅炉的长期动态特性进行了仿真研究，仿真结果正确。本文的研究为超临界直流锅炉的长期动态特性研究提供了一个十分简便的数学模型和方法。     

联合循环中底循环系统的动态仿真模型

根据底循环系统工作机理和特性，以能量和质量守恒原理为基础，详细论述了非补燃式三压再热自然循环余热锅炉、汽轮机、凝汽器、离心式水泵的模型算法，并结合其它相关模块算法（如凝结水预热器、流体网络、容积模块算法等），以M701F级联合循环机组为仿真对象，用模块化方法建立了完整的底循环系统动态数学模型。仿真试验表明：所建立的数学模型能够正确反映对象的动态和静态特性，整体模型运算收敛快，可为联合循环机组仿真系统的开发和底循环控制系统的设计与分析提供良好的理论模型。图3表1参12     

余热锅炉仿真建模方法的探讨

作为燃气蒸汽联合循环系统中的重要设备，余热锅炉对整个系统的性能起到决定性作用。应用仿真技术进行余热锅炉系统性能研究是一项切实可行的方法，也是进行余热锅炉设计的重要辅助手段。列举了余热锅炉结构及热力特性，系统划分、建模方法、参数选取、二次建模等，并对建模及计算方面要注意的问题进行了详细的阐述。     

改造余热锅炉的挡板实现快速启动

通过对VEGA 206型燃气-蒸汽联合循环设备特点进行分析和探索，从缩短余热锅炉汽轮机的启动时间，提高联合循环的经济效益的角度出发，提出并实施余热锅炉挡板及其控制系统的改造，实现余热锅炉的快速启动，并对余热锅炉频繁快速启动对寿命及经济效益的影响进行初步评价。     

F级余热锅炉蒸汽温度控制策略

以9FA燃气轮机配套的余热锅炉为例,介绍了F级余热锅炉特点及蒸汽减温配置,主蒸汽温度、二级高压过热器出口温度及再热蒸汽温度的控制策略,过热度保护和最小流量保护的实现方法。机组启动阶段,IGV参与燃气轮机排气温度控制,此时采用IGV角度前馈来稳定启动期间的主蒸汽温度。     

9FA型燃气轮机联合循环性能研究

1引言西气东输工程促进了沿线燃气轮机联合循环电厂的建设,减轻了中东部地区的环境排放压力。燃气轮机联合循环发电系统高效低污染、启停迅速、调峰能力强。西气东输管道沿线有25台F级燃气轮机联合循环机组,其中GE公司9FA型燃气轮机联合循环发电机组13台。如何保证系统的稳定安     

Thermodynamic analysis of an LNG fuelled combined cycle power plant with waste heat recovery and utilization system

This paper has proposed an improved liquefied natural gas (LNG) fuelled combined cycle power plant with a waste heat recovery and utilization system. The proposed combined cycle, which provides power outputs and thermal energy, consists of the gas/steam combined cycle, the subsystem utilizing the latent heat of spent steam from the steam turbine to vaporize LNG, the subsystem that recovers both the sensible heat and the latent heat of water vapour in the exhaust gas from the heat recovery steam generator (HRSG) by installing a condensing heat exchanger, and the HRSG waste heat utilization subsystem. The conventional combined cycle and the proposed combined cycle are modelled, considering mass, energy and exergy balances for every component and both energy and exergy analyses are conducted. Parametric analyses are performed for the proposed combined cycle to evaluate the effects of several factors, such as the gas turbine inlet temperature (TIT), the condenser pressure, the pinch point temperature difference of the condensing heat exchanger and the fuel gas heating temperature on the performance of the proposed combined cycle through simulation calculations. The results show that the net electrical efficiency and the exergy efficiency of the proposed combined cycle can be increased by 1.6 and 2.84% than those of the conventional combined cycle, respectively. The heat recovery per kg of flue gas is equal to 86.27 kJ s^?1. One MW of electric power for operating sea water pumps can be saved. The net electrical efficiency and the heat recovery ratio increase as the condenser pressure decreases. The higher heat recovery from the HRSG exit flue gas is achieved at higher gas TIT and at lower pinch point temperature of the condensing heat exchanger. Copyright © 2006 John Wiley & Sons, Ltd.     

Engineering design and exergy analyses for combustion gas turbine based power generation system

This paper presents the engineering design and theoretical exergetic analyses of the plant for combustion gas turbine based power generation systems. Exergy analysis is performed based on the first and second laws of thermodynamics for power generation systems. The results show the exergy analyses for a steam cycle system predict the plant efficiency more precisely. The plant efficiency for partial load operation is lower than full load operation. Increasing the pinch points will decrease the combined cycle plant efficiency. The engineering design is based on inlet air-cooling and natural gas preheating for increasing the net power output and efficiency. To evaluate the energy utilization, one combined cycle unit and one cogeneration system, consisting of gas turbine generators, heat recovery steam generators, one steam turbine generator with steam extracted for process have been analyzed. The analytical results are used for engineering design and component selection.     

Exergy analysis of a cogeneration plant using coal gasification and solid oxide fuel cell

This paper presents exergy analysis of a conceptualized combined cogeneration plant that employs pressurized oxygen blown coal gasifier and high‐temperature, high‐pressure solid oxide fuel cell (SOFC) in the topping cycle and a bottoming steam cogeneration cycle. Useful heat is supplied by the pass‐out steam from the steam turbine and also by the steam raised separately in an evaporator placed in the heat recovery steam generator (HRSG). Exergy analysis shows that major part of plant exergy destruction takes place in gasifier and SOFC while considerable losses are also attributed to gas cooler, combustion chamber and HRSG. Exergy losses are found to decrease with increasing pressure ratio across the gas turbine for all of these components except the gas cooler. The fuel cell operating temperature influences the performance of the equipment placed downstream of SOFC. Copyright © 2005 John Wiley & Sons, Ltd.     

Analysis of parameters affecting the performance of gas turbines and combined cycle plants with vapor absorption inlet air cooling

The integration of an aqua‐ammonia inlet air‐cooling scheme to a cooled gas turbine‐based combined cycle has been analyzed. The heat energy of the exhaust gas prior to the exit of the heat recovery steam generator has been chosen to power the inlet air‐cooling system. Dual pressure reheat heat recovery steam generator is chosen as the combined cycle configuration. Air film cooling has been adopted as the cooling technique for gas turbine blades. A parametric study of the effect of compressor–pressure ratio, compressor inlet temperature, turbine inlet temperature, ambient relative humidity, and ambient temperature on performance parameters of plants has been carried out. It has been observed that vapor absorption inlet air cooling improves the efficiency of gas turbine by upto 7.48% and specific work by more than 18%, respectively. However, on the adoption of this scheme for combined cycles, the plant efficiency has been observed to be adversely affected, although the addition of absorption inlet air cooling results in an increase in plant output by more than 7%. The optimum value of compressor inlet temperature for maximum specific work output has been observed to be 25 °C for the chosen set of conditions. Further reduction of compressor inlet temperature below this optimum value has been observed to adversely affect plant efficiency. Copyright © 2013 John Wiley & Sons, Ltd.     

Energy and exergy analyses of a CFB‐based indirectly fired combined cycle power generation system

Combined cycle configuration has the ability to use the waste heat from the gas turbine exhaust gas using the heat recovery steam generator for the bottoming steam cycle. In the current study, a natural gas‐fired combined cycle with indirectly fired heating for additional work output is investigated for configurations with and without reheat combustor (RHC) in the gas turbine. The mass flow rate of coal for the indirect‐firing mode in circulating fluidized bed (CFB) combustor is estimated based on fixed natural gas input for the gas turbine combustion chamber (GTCC). The effects of pressure ratio, gas turbine inlet temperature, inlet temperatures to the air compressor and to the GTCC on the overall cycle performance of the combined cycle configuration are analysed. The combined cycle efficiency increases with pressure ratio up to the optimum value. Both efficiency and net work output for the combined cycle increase with gas turbine inlet temperature. The efficiency decreases with increase in the air compressor inlet temperature. The indirect firing of coal shows reduced use with increase in the turbine inlet temperature due to increase in the use of natural gas. There is little variation in the efficiency with increase in GTCC inlet temperature resulting in increased use of coal. The combined cycle having the two‐stage gas turbine with RHC has significantly higher efficiency and net work output compared with the cycle without RHC. The exergetic efficiency also increases with increase in the gas turbine inlet temperature. The exergy destruction is highest for the CFB combustor followed by the GTCC. The analyses show that the indirectly fired mode of the combined cycle offers better performance and opportunities for additional net work output by using solid fuels (coal in this case). Copyright © 2009 John Wiley & Sons, Ltd.     

On some perspectives for increasing the efficiency of combined cycle power plants

The paper proposes an analysis of some possibilities to increase the combined cycle plant efficiency to values higher than the 60% without resorting to a new gas turbine technology. Optimization of heat recovery steam generator (HRSG) with the use of parallel sections and of limit subcritical conditions (up to 220 bar) is the key elements to obtain this result.The HRSG optimization is sufficient to obtain combined cycle plant efficiencies of the order of 60% while, joining HRSG optimization with the use of gas turbine reheat (postcombustion) and gas to gas recuperation can lead the efficiency of the whole plant to the limit value of 65%. Results are proposed with reference to a turbine inlet temperature of 1500 K, corresponding to those of usual commercial D–F series gas turbine.     

Combined cycle versus one thousand diesel power plants: pollutant emissions,ecological efficiency and economic analysis

The increase in the use of natural gas in Brazil has stimulated public and private sectors to analyse the possibility of using combined cycle systems for generation of electrical energy. Gas turbine combined cycle power plants are becoming increasingly common due to their high efficiency, short lead times, and ability to meet environmental standards. Power is produced in a generator linked directly to the gas turbine. The gas turbine exhaust gases are sent to a heat recovery steam generator to produce superheated steam that can be used in a steam turbine to produce additional power. In this paper a comparative study between a 1000 MW combined cycle power plant and 1000 kW diesel power plant is presented. In first step, the energetic situation in Brazil, the needs of the electric sector modification and the needs of demand management and integrated means planning are clarified. In another step the characteristics of large and small thermoelectric power plants that use natural gas and diesel fuel, respectively, are presented. The ecological efficiency levels of each type of power plant is considered in the discussion, presenting the emissions of particulate material, sulphur dioxide (SO₂), carbon dioxide (CO₂) and nitrogen oxides (NO_x).