Effective ways to modernize outdated coal heat power plants

An analysis of the state of equipment of 72 outdated coal HPP (heat power plants) of a total capacity 14.3 GW with steam parameters before the turbines p _before ≤ 9 MPa, t _before = 420–540°С was performed. The equipment is characterized by a considerably low efficiency factor, even if it were converted to burning the natural gas, and by increased release of harmful substances. However, on the most part of the considered HPP, the steam turbines, unlike the boilers, have thus far retained the operation applicability and satisfactory reliability of performance. The analysis has shown that it makes sense to effectively modernize the outdated coal HPP by transformation of their equipment into combined-cycle plant (CCP) with coal gasification, which has high economic and ecological indicators due to thermodynamic advantage of the combined cycle and simpler purification of the generator gas in the process under pressure. As the most rational way of this transformation, the one was recognized wherein—instead of the existing boiler (boilers) or parallel to it—a gasification and gas turbine system is installed with a boiler-utilizer (BU), from which steam is fed to the HPP main steam pipe. In doing this, the basic part of the power station equipment persists. In the world, this kind of reconstruction of steam power equipment is applied widely and successfully, but it is by use of natural gas for the most part. It is reasonable to use the technology developed at Heat Engineering Research Institute (HERI) of hearth-steam gasification of coal and high-temperature purification of the generator gas. The basic scheme and measures on implementation of this method for modernization of outdated coal HPP is creation of CCP with blast-furnace of coal on the basis of accessible and preserved HPP equipment. CCP power is 120 MW, input-output ratio (roughly) 44%, emissions of hazardous substances are 5 mg/МJ dust, 20–60 mg/МJ SO₂, and 50–100 mg/МJ NO _х . A considerable decrease of specific CCP cost is expected: down to approximately half compared to that of CCP with coal gasification created elsewhere abroad. Verification and debugging of accepted solutions can be carried out at a small-scale pilot plant.     

1000 MW机组锅炉掺烧贫煤NOx排放的燃烧优化

国内大型燃煤电站锅炉在低负荷运行工况下NO_x排放浓度往往偏高。文中采用燃烧优化运行技术,降低某电厂1000 MW超超临界机组锅炉部分负荷运行时NO_x排放浓度。通过进行现场试验并与历史运行数据比较分析发现,锅炉运行氧量偏高和掺烧贫煤是该锅炉部分负荷运行时NO_x排放浓度偏高的主要原因。试验结果表明,采用燃烧优化技术可有效控制该锅炉低负荷时NO_x排放浓度。无论是单烧烟煤还是掺烧贫煤,在机组负荷为700MW时,采用中间4台磨(B、C、D、E磨)运行的磨组运行方式代替习惯5台磨运行方式,可实现较低的NO_x排放浓度目标和较高的锅炉效率。     

燃煤机组不同灵活性调节方案参与一次调频过程的经济性分析

提高燃煤发电机组运行高效灵活性是提高电网运行安全性的有效手段。采用GSE软件搭建了660 MW超临界燃煤机组动态仿真模型,研究了一次调频过程中4种热力系统调节方案下的主要热经济性参数和蓄热量的动态特性,定义了一次调频过程的热经济性指标,最终分析了一次调频作用时间和调节方案对平均标准煤耗率差值的影响规律。研究表明：一次调频升负荷过程,4种不同调节方案中的汽轮机输出功率和发电厂总效率均迅速升高,而发电标准煤耗率规律正好相反;锅炉和汽轮机系统蓄热量降低是4种方案可以参与一次调频的本质原因;平均标准煤耗率差值的最小值为-22.15 g/（kW·h）,出现在高加抽汽节流方案下且一次调频作用时间为90 s。     

汽轮机缸效率对热耗率影响的能级估算

汽轮机本体高、中、低压缸内效率对机组经济性有较大影响.本文以某厂600MW机组为例,探讨汽轮机各缸内效率对热耗率影响的能级估算方法,供火力发电厂300 MW,600 MW,1000 MW汽轮机组的经济运行参考.     

All-Russia Thermal Engineering Institute experience in using difficult to burn fuels in the power industry

This article presents the results of the research carried out at the All-Russia Thermal Engineering Institute (VTI) aimed at using saline coal, municipal solid waste and bark waste, sunflower husk, and nesting/ manure materials from poultry farms. The results of saline coal burning experience in Troitsk and Verkhny Tagil thermal power plants (TPP) show that when switching the boiler to this coal, it is necessary to take into account its operating reliability and environmental safety. Due to increased chlorine content in saline coal, the concentration of hydrogen chloride can make over 500 mg/m³. That this very fact causes the sharp increase of acidity in sludge and the resulting damage of hydraulic ash removal system equipment at these power stations has been proven. High concentration of HCl can trigger damage of the steam superheater due to high-temperature corrosion and result in a danger of low-temperature corrosion of air heating surfaces. Besides, increased HCl emissions worsen the environmental characteristics of the boiler operation on the whole. The data on waste-to-energy research for municipal solid waste (MSW) has been generalized. Based on the results of mastering various technologies of MSW thermal processing at special plants nos. 2 and 4 in Moscow, as well as laboratory, bench, and industrial studies, the principal technical solutions to be implemented in the modern domestic thermal power plant with the installed capacity of 24 MW and MSW as the primary fuel type has been developed. The experience of the VTI in burning various kinds of organic waste—bark waste, sunflower husk, and nesting/manure materials from poultry farms—has been analyzed.     

二次再热机组高效灵活发电创新理论与方法

为解决二次再热机组在频繁变负荷情况下经济性能偏低、灵活性较差等问题,研究了二次再热高效灵活发电创新理论和方法。基于单耗分析方法揭示了传统二次再热机组全工况能耗分布规律,并提出5种适应电网调峰要求的典型600 ℃等级及以上的先进二次再热超超临界燃煤发电系统,分别为集成回热式小汽机新型循环、机炉深度耦合集成新循环、采用新型CO₂工质的循环、带储能的二次再热循环系统以及太阳能热互补二次再热循环系统,阐述了各循环系统的集成思路、系统特点以及对提高机组经济性和灵活性的优势。结果表明：锅炉、汽轮机、回热加热器具有较大的节能潜力;优选的集成回热式汽轮机的二次再热循环系统发电效率比基准系统煤耗降低了2.15 g/（kW·h）;提出的采用机炉耦合技术的二次再热机组在THA工况下煤耗降低高达3.6 g/（kW·h）;采用CO₂工质的火电系统在变工况下依然具有较高的效率;带储能的二次再热循环系统具有较好的灵活性;太阳能热互补二次再热循环系统节能潜力显著,达到14.73 g/（kW·h）。     

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.     

发电厂冷渣器冷却水回水接入点改造及经济性分析

北方联合电力有限责任公司蒙西发电厂2号300 MW循环流化床机组存在低压加热器凝结水温升过高、冷渣器循环效率低及凝结水流量过大等问题,主要原因是冷渣器回水接入点不合理。通过方案论证,对冷渣器冷却水回水接入点进行改造。改造后,低压加热器凝结水温升趋于设计值;汽轮机回热得到合理利用,汽轮机热耗由8680.97 kJ/kWh降至8382.5 kJ/kWh;供电煤耗由363 g/kWh降至359.8 g/kWh,提高了机组运行的经济性。同时通过凝结水泵电机变频改造等措施,解决了凝结水流量过大的问题。     

CFB锅炉热效率与环保特性及可靠性分析

为准确评价循环流化床(CFB)锅炉的运行经济性与可靠性,对10余台已投运的100～300 MWCFB锅炉的热效率、污染物排放特性及可用率进行了统计分析。分析结果表明,在燃用相同煤质的煤时,CFB锅炉热效率不低于煤粉锅炉。通过飞灰可燃物与煤指数的关系曲线,提出了降低难燃煤种飞灰可燃物的CFB锅炉设计方法。CFB锅炉具有良好环保特性,燃用高硫煤时其脱硫效率最高可达97.5%,NOx排放值一般小于200 mg/m3(标)。对影响CFB锅炉脱硫效率和可用率的因素进行了分析,提出了技术对策。     

在建大型火力发电厂节能分析与对策

以费县电厂600MW机组为背景, 分析影响电厂经济性的因素。认为煤质、锅炉效率( 排烟损失、不完全燃烧) 、汽机效率( 节流损失、初蒸汽参数、凝汽器背压、给水温度、系统泄漏、通流间隙调整) 、厂用电率是提高电厂节能水平的主要项目。针对每一项目提出了解决措施。     

燃煤电厂超低排放技术方案应用

中国煤种复杂多样,中高灰、中高硫煤在大型燃煤机组应用广泛,在火电污染物排放标准日益严格的背景下,讨论中高灰、中高硫煤种的超低排放技术路线的适用性以及进行技术路线的总结分析是非常必要的。对3台燃用中高灰分和中高硫分煤种的燃煤机组的超低排放技术路线的应用情况进行了分析。运行数据结果表明,燃用中高灰、中高硫分的煤种选择适当的技术路线可以使NOx、SO2和粉尘达到超低排放标准。提出了燃用中高灰分和中高硫分煤种机组的超低排放技术路线的选择建议。     

哈锅1 000 MW超超临界锅炉设计探讨

阐述了我国首台1000Mw超超临界燃煤锅炉的设计特点,并对所采用的设计煤种、蒸汽参数、炉膛尺寸、燃烧方式、水冷壁设计、高热强钢材、启动系统进行了分析,为我国开发更大容量超超临界机组,提高锅炉效率、降低发电成本和有害物质排放,提供了借鉴条件。     

掺烧贫煤超超临界塔式锅炉降低NOx的技术和应用

某电厂1000 MW超超临界螺旋管圈直流塔式炉,2012年投运以来在掺烧贫煤条件下SCR入口NO_x浓度达450 mg/m~3左右,不利于实现氮氧化物超低排放。文中通过对锅炉低氮燃烧改造的必要性和可行性进行分析,提出以高级复合空气分级低NO_x燃烧系统对原有燃烧系统进行改造并被采纳。2016年项目实施后,在掺烧贫煤条件下SCR入口NO_x质量浓度降低至300 mg/Nm~3,锅炉效率等指标良好,且无其他负面影响,实现了良好的经济效益、安全效益和环保效益。     

Turbokon scientific and production implementation company—25 years of activity

The main results of studies performed at ZAO Turbokon NPVP in cooperation with leading Russian scientific organizations during 25 years of its activity in the field of development of unique ecologically clean electric power and heat production technologies are described. They include the development and experimental verification using prototypes and full-scale models of highly efficient air-cooled condensers for steam turbines, a high temperature gas steam turbine for stationary and transport power engineering, a nonfuel technology of electric power production using steam turbine installations with a unit power of 4–20 MW at gas-main pipelines and industrial boiler houses and heat stations. The results of efforts in the field of reducing vibroactivity of power equipment for transport installations are given. Basic directions of further research for increasing the efficiency and ecological safety of home power engineering are discussed.     

电站锅炉入炉煤元素分析和发热量的软测量实时监测技术

文中提供了一种入炉煤元素分析和发热量的实时监测技术，该技术通过测量锅炉、汽轮机、磨煤机以及空气预热器的运行参数间接实现入炉煤元素分析和发热量的实时监测；它利用煤干燥无灰基元素的组成特性的基础性研究结果和能量守恒原理，从排烟气体成分中提取煤的干燥无灰基元素含量的信息；从磨煤机的运行状态中提取入炉煤收到基水分的信息；通过锅炉本体以及空气预热器的能量平衡分析，采用灰分校正技术，实现了入炉煤元素分析和发热量的实时监测。该技术可以为入炉煤质和锅炉效率的监测提供一种快速分析工具，帮助实现锅炉的优化运行。该技术已经在300MW的发电机组上应用成功，测试表明，收到基低位发热量的测量误差在-3．17％～ 3．83％之间。     

Introduction of Clean Coal Technology in Japan

Coal is a resource of which deposit is huge in amount, found throughout the world, and inexpensive and constant in price. For this reason, coal is expected to play a role as one of the energy supply sources in the world. The most critical issues to promote utilization of coal are to decrease the environmental load. In this report, the history, outline and recent developments of the clean coal technology in Japan, mainly the thermal power generation technology are discussed. As recent topics, here outlined first is the technology against global warming such as the improvement of steam condition for steam turbines, improvement of power generation efficiency by introducing combined generation, carbon neutral combined combustion of biomass, and carbon dioxide capture and storage (CCS) technology. Also introduced are outlines of Japanese superiority in application technology against NO_x and SO₂ which create acid rain, development status of the technical improvement in the handling method for coal which is a rather difficult solid‐state resource, and utilization of coal ash. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

加速发展大型循环流化床技术 推进电源结构优化升级

我国以煤炭为主的一次能源结构 ,决定了以燃煤电站为主的电源结构在较长的时间内将不会有大的改变 ,而电站锅炉燃烧排放的有害气体是大气的主要污染源之一。为了保护环境 ,实现电力产业可持续发展 ,世界发达国家开发利用洁净煤发电技术 ,特别是通过 2 0万kW级循环流化床锅炉的成功运行 ,推动了循环流化床技术向大型化发展。文章从技术路线和实施途径对我国引进 30万kW级大型循环流化床技术建设示范电站并开发 6 0万kW级超临界大型循环流化床锅炉技术 ,推进洁净煤发电技术的发展 ,推进电源结构优化升级 ,进行了分析研究。     

1000MW超超临界燃煤机组节能分析及优化

发电厂的竞争主要是成本竞争,加强节能技术的研究,对提升火力发电厂的技术经济水平和市场竞争力有重要的意义。对国华宁海发电厂1 000 MW超超临界燃煤机组锅炉燃烧及制粉系统、汽轮机凝汽器背压系统、辅控系统进行全面分析,实施了燃烧优化、汽轮机滑压曲线优化、电除尘闭环优化、空预器间隙改造以及辅控系统的综合治理,在节能方面取得了良好的效果,发电煤耗降低了5.91 g/kWh,厂用电率降低了0.7%,负荷系数增加了6.11%。     

基于能耗特性分析的双抽燃煤机组供汽优化

以优化运行、降低能耗为研究目标,考虑到大型燃煤机组热电联产变工况供汽运行模式的复杂性,建立了供热机组能耗分析模型.以某1 GW双抽机组为例,对9种供汽方案进行了能耗特性分析.结果表明,电负荷较低时,最优的供汽方式为冷再供中压、冷再供低压运行方式;电负荷较高时,最优的供汽方式为冷再供中压、中排供低压运行方式.在典型工况(...     

基于经济环保性能的低氮燃烧智能闭环控制策略研制与应用

分析了影响燃煤电厂锅炉低氮燃烧系统运行控制的因素,指出影响锅炉经济性的可变因素。阐述了低氮燃烧智能闭环控制的设计思想,并介绍了基于经济环保性能最佳的低氮燃烧闭环控制策略。介绍了该策略在某300 MW燃煤锅炉实施的技术路线与应用结果。