【作者】 张伟；

【导师】 程世庆；

【作者基本信息】 山东大学 ， 动力工程（专业学位）， 2025， 硕士

【摘要】 随着环保要求越发严格,十二五期间燃煤电站陆续增建脱硝系统,以控制烟气中的氮氧化物污染物。2014年8月,国家发展和改革委员会、国家能源局和环保部联合发布了《关于印发煤电节能减排升级与改造行动计划(2014—2020年)的通知》(发改能源[2014]2093号),提出到2020年,现有燃煤发电机组在完成改造后,平均供电煤耗应降低至310g/(kW·h)的水平。此后,国家能源局等相关部门陆续发布了发改运行[2015]518号、国能电力[2015]332号、国能科技[2015]333号等多项配套政策,进一步明确了节能环保调度、设备延寿及改造评估的标准与要求。2021年10月,国家发改委与国家能源局又联合发布了全国煤电机组改造升级实施方案(发改运行[2021]1519号),明确了煤电机组改造的三大目标:(1)针对供电煤耗较高的煤电机组,鼓励在条件允许的情况下加快节煤降耗改造;(2)对于具备供热潜力的纯凝机组,积极推进供热改造;(3)尽可能对现有煤电机组进行灵活性改造,以促进新能源的消纳。2022年,国家进一步加强了对燃煤电厂的节能减排要求,发布了《“十四五”节能减排综合工作方案》(国发[2022]15号),明确提出要加快推动煤电行业节能降碳改造、灵活性改造和供热改造“三改联动”,并强调了对重点区域、重点行业节能减排的严格监管。2023年,生态环境部发布了《关于进一步加强燃煤电厂大气污染治理的通知》(环大气[2023]12号),要求燃煤电厂进一步降低氮氧化物、二氧化硫和颗粒物的排放,推动超低排放技术的广泛应用。2024年,国家能源局发布了《关于推进煤电结构调整和转型升级的指导意见》(国能发[2024]23号),提出要优化煤电布局,加快淘汰落后产能,同时鼓励采用先进技术和设备提升煤电效率和环保水平。在这一系列政策背景下,本文针对华电潍坊发电有限公司二期660MW机组3#、4#锅炉空气预热器(空预器)的硫酸氢铵(ABS)堵塞问题,进行了堵塞成因分析和烟气余热防堵技术研究,并对空预器进行了技术改造。研究首先系统论述了空预器堵灰及其结露型积灰的成因,为分析潍坊公司二期空预器堵塞问题奠定了理论基础。空预器堵塞主要有酸露点腐蚀堵塞和硫酸氢铵(ABS)堵塞两类。影响结露型积灰的因素主要有炉型、含氧量、硫含量、钙含量、流速和温度分布等。影响ABS堵塞的因素主要有喷氨分布不均、NH3/NOx摩尔比、温度、负荷和催化剂活性等。其次,基于潍坊公司二期机组的运行情况,本文分析发现锅炉空预器存在严重的ABS堵塞现象,采用的暖风器防堵方式存在不足之处。根据运行数据和现场测试,本文论述了空预器防堵灰的主要技术路线:在强化吹灰冲洗技术、热风再循环技术、热风逆流预加热技术、烟气SBS喷射技术、前置暖风防堵技术等研究基础上,制定了对空预器蓄热元件三段改两段+Ⅱ段热管式空预器的功能性转移改造的技术路线,对蓄热元件进行了合理分层和板型优化,对Ⅱ段热管空预器布置进行了论证、性能计算及结构设计,对改造后的空预器的壁温进行了核算。同时,本文提出了空预器密封元件的修复方案和暖风机移位方案。最后,本文分析了二段热管空预器基于以上方案投运1个月后3#和4#机组空预器的运行结果。3#机组为基于4#机组的进一步优化,其A侧和B侧热管烟气侧差压分别为222Pa和239Pa,低于设计值240Pa;空气侧差压分别为134Pa和171Pa,低于设计值260 Pa;空气温升分别为32.4℃和31.2℃,高于设计值28.17℃;烟气侧温降分别为23.9℃和24.9℃,高于设计值20℃,热管效率分别为14.48%和15.08%,高于设计值12.12%。通过计算一次风机电耗、送风机电耗、引风机电耗、排烟温度、暖风器耗汽量、沉积系数等关键参数,确定热管空预器投运后,烟气降温幅度和烟气侧阻力满足设计要求,可有效提高空预器冷端综合温度,缓解冷端ABS结晶积灰堵塞,减少空预器排烟损失,电厂经济效益提高。基于改造前后空预器的运行情况,本文总结了空预器功能性转移及低温段热管空预器防堵技术的优缺点、应用范围及其推广建议。综上所述,本文对空预器堵灰原因及现有防堵技术进行了全面、系统的研究,对空预器功能性转移及低温段热管空预器防堵技术进行了重点研究,形成了“预热器功能性转移及低温段热管空气预热器技术”的基础理论和典型设计,并通过对潍坊公司二期660 MW机组热管空预器改造项目的运行实践,形成了低温段热管空预器技术应用推广指导意见。该技术可解决回转式空预器蓄热元件易堵塞、阻力大、漏风率大、排烟温度高等问题,具有显著的优越性和推广价值。更多还原

【Abstract】 With increasingly strict environmental requirements,coal-fired power plants will gradually build denitrification systems during the 12th Five Year Plan period to control nitrogen oxide pollutants in flue gas.In August 2014,the National Development and Reform Commission,the National Energy Administration,and the Ministry of Environmental Protection jointly issued the "Notice on Issuing the Action Plan for Energy Conservation and Emission Reduction Upgrading and Transformation of Coal fired Power Plants(2014-2020)"(NDRC Energy[2014]No.2093),proposing that by 2020,the average coal consumption for power supply of existing coal-fired power generators should be reduced to 310g/(kW·h)after renovation.Subsequently,the National Energy Administration and other relevant departments successively issued multiple supporting policies such as Development and Reform Commission Operation[2015]No.518,National Energy Electric Power[2015]No.332,and National Energy Science and Technology[2015]No.333,further clarifying the standards and requirements for energy conservation and environmental protection scheduling,equipment life extension,and renovation evaluation.In October 2021,the National Development and Reform Commission and the National Energy Administration jointly released the National Implementation Plan for the Renovation and Upgrading of Coal fired Power Units(NDRC Run[2021]No.1519),which clarified the three major goals of coal-fired power unit renovation:(1)for coal-fired power units with high coal consumption for power supply,encourage the acceleration of coal saving and consumption reduction renovation if conditions permit;(2)For pure condensing units with heating potential,actively promote heating renovation;(3)Make flexible modifications to existing coal-fired power units as much as possible to promote the consumption of new energy.In 2022,the country further strengthened the requirements for energy conservation and emission reduction of coal-fired power plants,and issued the "Comprehensive Work Plan for Energy Conservation and Emission Reduction in the 14th Five Year Plan"(Guofa[2022]No.15),which clearly stated the need to accelerate the "three reforms linkage" of energy conservation and carbon reduction,flexibility transformation,and heating transformation in the coal-fired power industry,and emphasized strict supervision of energy conservation and emission reduction in key areas and industries.In 2023,the Ministry of Ecology and Environment issued the "Notice on Further Strengthening the Control of Air Pollution from Coal fired Power Plants"(Huan Da Shui[2023]No.12),requiring coal-fired power plants to further reduce the emissions of nitrogen oxides,sulfur dioxide,and particulate matter,and promote the widespread application of ultra-low emission technologies.In 2024,the National Energy Administration issued the "Guiding Opinions on Promoting the Adjustment and Transformation of Coal and Electricity Structure"(Guoneng Fa[2024]No.23),proposing to optimize the layout of coal and electricity,accelerate the elimination of outdated production capacity,and encourage the use of advanced technology and equipment to improve coal and electricity efficiency and environmental protection level.In the context of this series of policies,this article focuses on the problem of ammonium bisulfate(ABS)blockage in the air preheaters(air preheaters)of boilers 3#and 4#of Huadian Weifang Power Generation Co.,Ltd.’s Phase Ⅱ 660MW unit.The causes of blockage were analyzed,and flue gas waste heat anti blockage technology was studied.Technical modifications were also made to the air preheaters.The study first systematically discussed the causes of air preheater blockage and condensation type dust accumulation,laying a theoretical foundation for analyzing the blockage problem of the second phase air preheater in Weifang Company.The main types of air preheater blockage are acid dew point corrosion blockage and ammonium bisulfate(ABS)blockage.The main factors affecting condensation type ash deposition include furnace type,oxygen content,sulfur content,calcium content,flow rate,and temperature distribution.The main factors affecting ABS blockage include uneven distribution of ammonia injection,NH3/NOx molar ratio,temperature,load,and catalyst activity.Next,this thesis revealed substantial ABS blocking in the APH,as illustrated by the operational characteristics of the Weifang Power Plant Phase Two,highlighting the inadequacies in the use of the air heater designed to prevent such blocking.In addition,it outlined key strategies for mitigating dust blocking in the APH,and provided a thorough analysis of the operational principles,benefits,and drawbacks of various anti-blocking technologies,including enhanced soot flushing,hot air recirculation,hot air counterflow preheating,SBS InjectionTM,and preheating.Consequently,this research led to an optimized technological framework for anti-blocking solutions,where the APH heat storage component layers were reduced from three to two,with the lower layer being replaced by heat pipes.Additionally,this study refined the materials and configurations of the heat storage components,validated the design of heat pipe layer,and assessed the APH wall temperature following modification.It also proposed methods for repairing APH sealing components and reallocating air heaters.Finally,this thesis conducted an analysis of the operational performance of the modified APH Units#3 and#4 at the Weifang Power Plant Phase Two.The Unit#3,which had been further optimized compared to Unit#4,recorded a flue gas differential pressure of 222 Pa on the A side and 239 Pa on the B side,both falling below the design specification of 240 Pa.The air differential pressures on the two sides were measured at 134 Pa and 171 Pa,respectively,which also did not exceed the design value of 260 Pa.Additionally,the air temperatures increased by 32.40℃ and 31.2℃,exceeding the design target of 28.17℃ while the flue gas temperatures decreased by 23.9℃ and 24.9℃,surpassing the design target of 20℃.The heat pipe efficiencies were recorded at 14.48%and 15.08%,both of which exceeded the design benchmark of 12.12%.By assessing critical parameters such as the power consumption of the primary fan,supply fan,and induced draft fan,along with exhaust temperature,heater steam usage,and sedimentation coefficient,this study confirmed that the operation of the heat pipe APH resulted in flue gas cooling amplitude and flue gas resistance that align with design specifications.This operation could significantly enhance the overall temperature at the APH low-temperature end,mitigate issues related to ABS crystallization and ash blocking at that end,decrease exhaust losses from the APH,and ultimately boost the economic performance of the power plant.This thesis conducted a comprehensive evaluation of the APH’s performance before and after its renovation,highlighting the strengths and weaknesses,potential applications,and recommendations for the advancement of preheater functional transformation and low-temperature-end heat pipe APH anti-blocking technology.In summary,this thesis presents a thorough and methodical investigation into the factors contributing to ash blocking in the APH,alongside an evaluation of current anti-blocking technologies.It emphasizes the APH functional transformation and heat pipe anti-blocking design,thereby establishing foundational theories and standard designs related to "Air Preheater Functional Transformation and Low-Temperature-End Heat Pipe Technology".Through a detailed analysis and theoretical validation of the operational performance of the 660 MW unit heat pipe APH renovation project at the Weifang Power Plant Phase Two,this study provides valuable insights for the implementation and dissemination of APH low-temperature-end heat pipe technology.This innovative approach offers considerable benefits and potential for addressing issues such as clogging,elevated resistance,excessive air leakage,and high exhaust temperatures associated with the heat storage components of the rotary APH.更多还原