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.

Improving Prediction Accuracy of a Rate-Based Model of an MEA-BasedCarbon Capture Process for Large-Scale Commercial Deployment

Carbon capture and storage （CCS） technology will play a critical role in reducing anthropogenic carbondioxide （CO2） emission from fossil-fired power plants and other energy-intensive processes. However, theincrement of energy cost caused by equipping a carbon capture process is the main barrier to its commer-cial deployment. To reduce the capital and operating costs of carbon capture, great efforts have been madeto achieve optimal design and operation through process modeling, simulation, and optimization. Accuratemodels form an essential foundation for this purpose. This paper presents a study on developing a moreaccurate rate-based model in Aspen Plus for the monoethanolamine （MEA）-based carbon capture processby multistage model validations. The modeling framework for this process was established first. The steady-state process model was then developed and validated at three stages, which included a thermodynamicmodel, physical properties calculations, and a process model at the pilot plant scale, covering a wide rangeof pressures, temperatures, and CO2 loadings. The calculation correlations of liquid density and interfacialarea were updated by coding Fortran subroutines in Aspen Plus. The validation results show that the cor-relation combination for the thermodynamic model used in this study has higher accuracy than those ofthree other key publications and the model prediction of the process model has a good agreement with thepilot plant experimental data. A case study was carried out for carbon capture from a 250 MWe combinedcycle gas turbine （CCGT） power plant. Shorter packing height and lower specific duty were achieved usingthis accurate model.

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.

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

许多 F 班气体汽轮机联合了周期(GTCC ) 发电厂因为更少的排放和高效率，目前在中国被造。调查 GTCC 植物的效率改进兴趣大。一个联合周期与三压力再热热恢复蒸气生成器(HRSG ) 在这份报纸为学习被选择。以便最大化 GTCC 效率，操作参数的 HRSG 的优化被执行。操作参数借助于热力学的分析被决定，即 exergy 损失的最小化。蒸气 bottoming 周期效率上的 HRSG 入口气体温度的影响被讨论。当它是超过 590 掳 C 时，结果证明增加 HRSG 入口温度有更少的改进到蒸气周期效率。到在超过的周期的煤气的恢复的部分气体被学习。与气体的使用加入 HRSG 优化到煤气的热恢复，联合植物效率能在基础负担升起直到 59.05% 。另外， GTCC 发电厂的部分负担表演变得好一些。效率被 2.11% 在 50% 负担在 75% 负担并且在 4.17% 增加。

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.

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。

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。

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。

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.

燃气-蒸汽联合循环热经济学分析评价指标研究

为满足能源结构优化和电网快速调峰需求,燃气-蒸汽联合循环机组得到快速发展,对联合循环及其内部组元的性能评价提出了更高要求。基于热力学第一定律和第二定律的传统方法无法考虑非能量费用的影响,而热经济学中矩阵热经济学又无法评价联合循环内部组元的技术-经济性能。该文基于热经济学结构理论,建立了联合循环成本模型;在传统的热经济学性能评价指标中引入了权重系数,提出了一种新的评价指标用于性能评价。结合联合循环的3个典型工况,对该文模型和组元评价指标进行了分析和验证。结果表明,该文模型和组元评价指标结果合理,可以为联合循环系统的热经济学优化等后续研究提供性能指标的支撑。

燃气-蒸汽联合循环发电CO_2排放量量化方法比较

为探究排放因子法与监测法两类量化方法对燃气-蒸汽联合循环发电CO_2排放源排放量量化的差异和影响因素,采用《温室气体排放核算与报告要求第1部分:发电企业》(下称《核算报告要求》)和《2006年IPCC国家温室气体清单指南》(下称《IPCC指南》)两种排放因子法,以及一种基于红外吸收光谱原理的排放源监测法,对某燃气-蒸汽联合循环发电CO_2排放源排放量进行4次量化,分别得出监测法、《核算报告要求》以及《IPCC指南》下限值、缺省值和上限值5组量化值.结果表明:(1)采用监测法得出的CO_2排放源排放量量化值明显小于两种指南排放因子法量化结果;(2)采用《核算报告要求》得出的CO_2排放源排放量量化值介于《IPCC指南》缺省值和下限值的量化值之间;(3)《核算报告要求》和《IPCC指南》中的天然气排放因子值分别超出此次监测法量化值折算出的天然气排放因子值的22%、19%、23%和28%,证明存在因高估排放因子导致高估CO_2排放量的可能;(4)装置运行负荷率越高,采用排放因子法得出的量化值越趋近于监测法量化值.研究显示,在监测条件良好的情况下,宜采用监测法对燃气-蒸汽联合循环发电CO_2排放源排放量进行量化,可避免燃料燃烧特性值和装置负荷率对排放因子法量化准确性的干扰,能更好地支撑企业和管理部门的统计量化工作.

分布式热泵调峰型燃气热电联产烟气余热回收供热系统建模及模拟分析

将分布式热泵调峰技术与基于直接接触式换热的燃气热电厂烟气余热回收系统相结合，构建一种分布式热泵调峰型燃气热电联产烟气余热回收供热系统。介绍这种新的系统形式，并以一套二拖一大型9F级燃气蒸汽联合循环背压供热机组为例，进行系统的配置并对系统关键参数进行分析。