Performance of Gas-Steam Combined Cycle Cogeneration Units Influenced by Heating Network Terminal Steam Parameters

The determination of source-side extracted heating parameters is of great significance to the economic operation of cogeneration systems.This paper investigated the coupling performance of a cogeneration heating and power system multidimensionally based on the operating characteristics of the cogeneration units,the hydraulic and thermodynamic characteristics of the heating network,and the energy loads.Taking a steam network supported by a gas-steam combined cycle cogeneration system as the research case,the interaction effect among the source-side prime movers,the heating networks,and the terminal demand thermal parameters were investigated based on the designed values,the plant testing data,and the validated simulation.The operating maps of the gas-steam combined cycle cogeneration units were obtained using THERMOFLEX,and the minimum source-side steam parameters of the steam network were solved using an inverse solution procedure based on the hydro-thermodynamic coupling model.The cogeneration operating maps indicate that the available operating domain considerably narrows with the rise of the extraction steam pressure and flow rate.The heating network inverse solution demonstrates that the source-side steam pressure and temperature can be optimized from the originally designed 1.11 MPa and 238.8°C to 1.074 MPa and 191.15°C,respectively.Under the operating strategy with the minimum source-side heating parameters,the power peak regulation depth remarkably increases to 18.30%whereas the comprehensive thermal efficiency decreases.The operation under the minimum source-side heating steam parameters can be superior to the originally designed one in the economy at a higher price of the heating steam.At a fuel price of$0.38/kg and the power to fuel price of 0.18 kg/(kW·h),the critical price ratio of heating steam to fuel is 119.1 kg/t.The influence of the power-fuel price ratio on the economic deviation appears relatively weak.

Model Selection of Gas Turbine for Large Scale Gas-Fired Combined Cycle Power Plant

This paper briefs the configuration and performance of large size gas turbines and their composed combined cycle power plants designed and produced by four large renown gas turbine manufacturing firms in the world, providing reference for the relevant sectors and enterprises in importing advanced gas turbines and technologies.

Application of Combined Cycle in Modernized Retrofit of Old Thermal Power Plants

This article expounds the advantages and three schemes of applying combined cycle to the modernized retrofit of old thermal power plants. Through analyzing and comparing technical economics of these three schemes, it is concluded that to use feedwater heating and heat recovery steam generator (HRSG) is suitable for the units with unit capacity below 100 MW, while to use exhaust gas reburning is suitable for units with unit capacity of 125 MW, 200 MW and above.

Monte Carlo Simulation of a Combined-Cycle Power Plant Considering Ambient Temperature Fluctuations

A combined-cycle power plant (CCPP) is broadly utilized in many countries to cover energy demand due to its higher efficiency than other conventional power plants. The performance of a CCPP is highly sensitive to ambient air temperature (AAT) and the generated power varies widely during the year with temperature fluctuations. To have an accurate estimation of power generation, it is necessary to develop a model to predict the average monthly power of a CCPP considering ambient temperature changes. In the present work, the Monte Carlo (MC) method was used to obtain the average generated power of a CCPP. The case study was a combined-cycle power plant in Tehran, Iran. The region’s existing meteorological data shows significant fluctuations in the annual ambient temperature, which severely impact the performance of the mentioned plant, causing a stochastic behavior of the output power. To cope with this stochastic nature, the probability distribution of monthly outdoor temperature for 2020 was determined using the maximum likelihood estimation (MLE) method to specify the range of feasible inputs. Furthermore, the plant was accurately simulated in THERMOFLEX to capture the generated power at different temperatures. The MC method was used to couple the ambient temperature fluctuations to the output power of the plant, modeled by THERMOFLEX. Finally, the mean value of net power for each month and the average output power of the system were obtained. The results indicated that each unit of the system generates 436.3 MW in full load operation. The average deviation of the modeling results from the actual data provided by the power plant was an estimated 3.02%. Thus, it can be concluded that this method helps achieve an estimation of the monthly and annual power of a combined-cycle power plant, which are effective indexes in the economic analysis of the system.

DESIGN OF COMBINED CYCLE GENERATION SYSTEM WITH HIGH TEMPERATURE FUEL CELL AND STEAM TURBINE

For environment protection and high efficiency, development of new conceptpower plant has been required in China. The fuel cell is expected to be used in a power plant as acentralized power Station or distributed power plant. It is a chemical power generation device thatconverts the energy of a chemical reaction directly into electrical energy and not limited by Carnotcycle efficiency. The molten carbonate fuel cell (MCFC) power plant has several attractive featuresi.e. high efficiency and lower emission of NO_x and SO_x A combined cycle generation system withMCFC and steam turbine is designed. Its net electrical efficiency LHV is about 55 percent.

Optimization Potentials for the Waste Heat Recovery of a Gas-Steam Combined Cycle Power Plant Based on Absorption Heat Pump

A new waste heat recovery system is presented to recover exhausted steam waste heat from the steam turbine by absorption heat pump(AHP) in a gas-steam combined cycle(GSCC) power plant. The system can decrease energy consumption and further improve the energy utilization. The performance evaluation criteria are calculated, and exergy analysis for key components are implemented in terms of the energy and exergy analysis theory. Besides, the change of these criteria is also revealed before and after modification. The net power output approximately increases by 21738 kW, and equivalent coal consumption decreases by 5.58 g/kWh. A 1.81% and 1.92% increase in the thermal and exergy efficiency is respectively obtained in the new integrated system as the heating load is 401095 kJ at 100% condition. Meanwhile, the appropriate extraction parameters for heating have been also analyzed in the two systems. The proposed scheme can not only save energy consumption but also reduce emission and gain great economic benefit, which is proven to be a huge potential for practical application.

Performance Improvement of Combined Cycle Power Plant Based on the Optimization of the Bottom Cycle and Heat Recuperation

Many F class gas turbine combined cycle （GTCC） power plants are built in China at present because of less emission and high efficiency. It is of great interest to investigate the efficiency improvement of GTCC plant. A combined cycle with three-pressure reheat heat recovery steam generator （HRSG） is selected for study in this paper. In order to maximize the GTCC efficiency, the optimization of the HRSG operating parameters is performed. The operating parameters are determined by means of a thermodynamic analysis, i.e. the minimization of exergy losses. The influence of HRSG inlet gas temperature on the steam bottoming cycle efficiency is discussed. The result shows that increasing the HRSG inlet temperature has less improvement to steam cycle efficiency when it is over 590℃. Partial gas to gas recuperation in the topping cycle is studied. Joining HRSG optimization with the use of gas to gas heat recuperation, the combined plant efficiency can rise up to 59.05% at base load. In addition, the part load performance of the GTCC power plant gets much better. The efficiency is increased by 2.11% at 75% load and by 4.17% at 50% load.

Identifying Critical Components of Combined Cycle Power Plants for Implementation of Reliability-centered Maintenance

Maintenance scheduling and asset management practices play an important role in power systems,specifically in power generating plants.This paper presents a novel riskbased framework for a criticality assessment of plant components as a means to conduct more focused maintenance activities.Critical components in power plants that influence overall system performance are identified by quantifying their failure impact on system reliability,electric safety,cost,and the environment.Prioritization of plant components according to the proposed risk-based method ensures that the most effective and techno-economic investment decisions are implemented.This,in turn,helps to initiate modern maintenance approaches,such as reliability-centered maintenance(RCM).The proposed method is applied to a real combined cycle power plant(CCPP)in Iran,composed of two gas turbine power plants(GTPP)and one steam turbine power plant(STPP).The results demonstrate the practicality and applicability of the presented approach in real world practices.

A practical approach to improve alarm system performance: Application to power plant

Process safety in chemical industries is considered to be one of the important goals towards sustainable development. This is due to the fact that, major accidents still occur and continue to exert significant reputational and financial impacts on process industries. Alarm systems constitute an indispensable component of automation as they draw the attention of process operators to any abnormal conditi on in the plant. Therefore, if deployed properly, alarm systems can play a critical role in helping plant operators ensure process safety and profitability. How-ever, in practice, many process plants suffer from poor alarm system configuration which leads to nuisance alarms and alarm floods that compromise safety. A vast amount of research has primarily focused on developing sophisticated alarm management algorithms to address specific issues. In this article, we provide a simple, practical, systematic approach that can be applied by plant engineers (i.e., non-experts) to improve industrial alarm system performance. The proposed approach is demonstrated using an industrial power plant case study.

CCPP机组余热锅炉高压蒸发器泄漏分析与处理

燃气-蒸汽联合循环机组(CCPP)作为高效能源转换系统,在钢铁等工业领域得到广泛应用。余热锅炉作为CCPP机组的核心部件,其稳定运行直接关系到整个机组的效率和安全性。文章针对某钢厂燃气轮机组配套余热锅炉高压蒸发器上部迎烟气面频繁泄漏问题进行了深入研究,分析泄漏原因为其下联箱内沉积物导致蒸发器管内水流量减小,进而产生汽水混合物的冲击腐蚀,同时炉膛局部区域的“烟气走廊”现象加剧了这一腐蚀过程。针对这一问题,采取更换泄漏管段、改造下联箱定排管系统以提高排污效率、修复和完善烟气挡板以减少“烟气走廊”形成、优化定期排污操作以及制定定期的检查和维护计划等措施,有效地解决了高压蒸发器的泄漏问题,提高了设备的稳定性和安全性。

燃气发电厂电气能耗分析与节能降耗措施研究

该文依据近年来国际能源形势和国家的能源政策并结合燃气发电厂的特性,从企业生产成本、运营管理规范性、电磁损耗、辅机电气损耗和照明电气损耗等角度出发,对燃气发电厂存在的电气节能降耗问题进行探究分析,并提出具体的节能降耗措施。分析表明,通过优化电气设备的性能和管理模式,可以达到节能降耗和提高燃气电厂的经济效益的目的。

联合循环发电站电力输出预测

为了使联合循环发电站利润最大化,准确预测其满负载电力输出非常重要。联合循环发电站运行时,前一级产生的废气被用来驱动下一级热机,以此来推动发电机,其满负载电力输出受到环境温度、大气压强、相对湿度和废气气压的影响。为此,首先,采用核主成分分析(kernel principle component analysis,KPCA)对电站发电相关的特征进行特征组合降维完成特征提取;然后,采用极端梯度提升(extreme gradient boosting,XGBoost)算法进行特征重要性评分,并结合序列前向选择法(forward selection,FS)获取最优特征子集;最后,构建了KPCA-XGB-FS模型用于联合循环发电站满负载下小时电力输出预测。通过对某联合发电站的真实数据进行实验,并与使用相同数据的已有研究方法进行对比,结果表明,所提出方法能够有效对电力输出进行预测,预测结果优于已有的研究方法。

掺烧绿氢对联合循环发电系统热力性能影响研究

随着我国电力产业从化石能源向清洁低碳能源转变,考虑提高可再生能源在电力系统中的占比对推动能源消费革命具有重要意义。研究了燃气-蒸汽联合循环发电机组掺烧绿氢对系统热力性能的影响。分析了H 2掺混比例从10%提高到50%过程中,所需燃料的质量流量、燃机的排烟参数、燃气轮机和汽轮机的出力以及系统在不同工况下的年CO_(2)减排量的变化。研究结果表明,随着H_(2)掺混比例的提高,燃汽轮机的排烟温度从593.3℃升高到623.19℃,燃气流量从653.9 kg/s下降到592.4 kg/s,汽轮机出力提高了0.15%,而燃气轮机的出力降低。此外,当H 2掺混比例为50%以及在满负荷工况下,系统年CO_(2)减排量为26.64×10^(4)t。

燃气-蒸汽联合电厂冷却塔选型配置研究

冷却塔塔型的合理选择是电厂安全可靠、经济高效运行的重要保证。以某1×470 MW级燃气—蒸汽联合电厂为例,首先针对带机械通风冷却塔的二次循环供水系统进行优化分析计算,然后采用“冷效相同”原则,对本工程循环水系统采用不同塔型的方案进行技术经济比较。

改进型低热值煤气联合循环发电机组在马钢的实践与应用

马钢183 MW低热值煤气联合循环发电机组采用先进的发电生产工艺提高煤气资源综合利用效率,利用5G通讯和私有数据云技术,构建智慧电厂。实现机组运行参数在线自我分析和设备健康状态的自我诊断,有力保障机组高效、稳定、长周期安全运行。联合循环机组的建设对于马钢节能减排和循环经济的发展起到推动作用。

高超声速涡轮/冲压组合发动机方案

为满足高超声速运输机在宽广的工作范围内（Ma=0～5，H=0～30km）稳定，可靠工作，研究了涡轮，冲压组合动力装置并联方案．完成了涡扇发动机和冲压发动机的总体性能方案设计，2种工作模式转换过程和沿飞行轨迹的组合发动机稳态特性模拟也已接近尾声．建立了适合高超声速飞行的涡扇发动机、冲压发动机可变几何的部件级详细性能计算模型，比较分析了涡扇发动机的加力方案；考虑了进气道，发动机流量匹配对发动机特性的影响；给出了涡轮，冲压模式转换阶段的稳态性能仿真结果．

高超声速串联式组合动力装置方案

为保证高超声速运输机在宽广的飞行包线内（Ma=0—5，H=0—30km）稳定可靠工作，对涡轮／冲压组合动力装置串联方案展开研究．首先建立了经试验数据校核的适于高超声速飞行的组合动力装置部件级变循环详细非线性性能计算模型；在此基础上，利用发动机设计点热力循环分析和非设计点性能分析方法对串联方案的综合特性进行评估，最终给出一种经过优化的串联布局涡扇／冲压组合动力装置总体性能设计方案．研究结果表明，优化方案可有效地缩小组合发动机的结构尺寸与重量，有利于进气道，喷管的调节以及冲压燃烧室燃烧的组织．通过综合调整发动机5个可调几何部位以及涡轮发动机燃油流量和冲压燃烧室燃油流量，可以实现涡扇／冲压模式的平稳转换．

贾汪增压流化床燃烧联合循环中试电站的设计概念

本文概述贾汪增压流化床燃烧联合循环(PFBC-CC)中试电站的设计概念,介绍了该中试电站的研究目标、规模和选址、系统、设计技术关键和实施计划。

基于Shell煤气化工艺的干煤粉加压气流床气化炉性能研究

以Shell煤气化工艺为基础,利用干煤粉加压气流床气化过程模拟模型,对干煤粉加压气流床气化工艺的性能进行了数学模拟和性能研究.分析了煤气化过程中氧气和蒸汽对气化炉性能的影响,为整体煤气化联合循环(IGCC)电站系统设计中气化工艺及参数的选择提供了依据.研究表明,氧气煤比和蒸汽煤比是影响气化炉出口煤气成分、碳转化率和其他性能的主要因素,气化炉温度随着氧气煤比的增加而增加,随着蒸汽煤比的增加而下降;当蒸汽煤比一定时,随着氧气煤比的变化,冷煤气效率有一个最佳值,氧气煤比要比蒸汽煤比对气化炉性能的影响更为显著.

煤气脱水技术综述

用钢铁厂副产品煤气发电是钢铁企业降低能耗、节约成本的重要途径.低热值煤气联合循环发电机组(CCPP)已应用在钢铁企业.现在普遍使用湿法回收的煤气中机械水含量偏高,这既影响CCPP的安全运行,又降低了煤气的热值.本文介绍了当前煤气脱水的主要方式、研究现状及发展方向,提出了适用于CCPP的低成本、高效率煤气脱水新方法.