某燃气轮机热电减温水喷嘴频繁堵塞原因分析及防治措施

某燃气轮机电站运行中制冷站减温水喷嘴频繁堵塞,喷嘴需经常人工清理,管道输送泵压力、频率和开度增大,电耗增加,严重影响制冷机系统正常运行状态。通过现场系统查定、减温水水质分析、堵塞物能谱分析等技术手段,分析发生异常现象的原因并得出初步结论,并针对性提出合理有效的防治措施。     

下期部分论文题目

绍兴大明发电有限公司1#余热锅炉型号为Q387／543-65—3．82／445，卧式烟道式单汽包自然循环锅炉，采用喷水减温。锅炉投产初期，出现因减温水流量不足，造成主汽超温被迫减负荷运行的现象。停炉后，检查发现减温器部份减温水喷嘴被焊渣、金属屑堵塞，造成减温水流量减少。将杂物清除后继续投运，运行不久此种状况继续发生，被迫减负荷运行或停炉清理，造成较大的经济损失。     

超临界锅炉减温水引发氧化皮剥落问题的分析与防范

超(超)临界机组锅炉高温炉管内壁氧化皮剥落堵塞引起的过热爆管是近几年来困扰机组安全运行的突出问题之一。在对两起爆管事件进行失效分析过程发现,锅炉启动过程因减温水投用不当会大大促进氧化皮的集中剥落。通过列举两起爆管案例,查阅了减温水投用记录,进一步分析表明氧化皮的集中剥落与减温水投用不当有很强的关联性。针对减温水引发的过热爆管提出的防范措施可供生产实践借鉴。     

喷水减温对机组热经济性影响的研究

针对国产330MW机组,分析了两种运行工况下,过热器、再热器喷水量对其经济性的影响。结果表明,在运行过程中,减温水量过大会影响机组运行的经济性,减温水量增加相同的条件下,再热器减温水导致机组煤耗率增加值是过热器的10倍多。再热器减温水量过大对机组经济性的影响远大于过热器。     

国产首台325 MW燃油燃气发电机组锅炉

分析了国产首台325MW燃气燃油发电机组锅炉的设计特点与初步运行效果。满负荷时,100%燃油工况,减温水量5～20t/h;100%燃气工况,过热器减温水量100-120t/h,再热器减温水量25-35t/h。各项参数正常,受到外方用户的好评。根据安装和调试运行情况,对改进系统、完善产品设计提出建议。     

1025t/h控制循环锅炉燃烧器摆动调温研究

1025t／b控制循环锅炉采用燃烧器喷嘴摆动调节过热蒸汽和再热蒸汽温度。锅炉投运后曾经发生燃烧器喷嘴摆动装置故障，不起调温作用，汽轮机高压缸排汽温度比设计值高10～20℃，被迫采取各用事故喷水调节再热蒸汽温度。锅炉再热器受热面偏大；使再热器减温水量比设计值多20-30tt/h，明显影响机组运行经济性。通过调查研究和实炉试验，对摆动机构采取改进措施。现在燃烧器喷嘴已能正常摆动，找到了减少再热器减温水量的途径。     

喷水减温器内部过程的数值模拟

从液体破碎的基本原理出发,提出了减温水自喷嘴喷入蒸汽流后初始液滴的形成,二次破碎及其后的汽化物理模型。在此基础上引入适当的假设、对蒸汽与减温水的相互作用及其流动过程作了数值模拟,从而得到了汽化长度的定量描述。     

回热系统能损分析中基准值的在线确定

对回热系统主要监测参数的运行基准值进行在线计算，主要针对变工况下加热器的端差、抽汽压损的基准值定量计算，对过热器减温水量的基准值的在线计算模型进行了分析，并籍此对某电厂300MW汽轮机组进行了计算分析。回热系统运行基准值对于指导运行，在线分析及故障诊断有一定的现实意义。     

喷水减温系统改造及经济性分析

某电厂喷水减温系统具有较大节能潜力,对喷水减温系统进行了改造,过热减温水由目前的给水泵出口母管引接,改为由高加出口给水母管引接。为了确定过热减温水系统改造后的经济性变化,采用热力系统建模方法进行了不同运行工况的计算。结果表明负荷在330~660 MW负荷变化范围内,经技术改造后供电煤耗平均降低值在0.80 g/k W·h以上,净热耗率的降低值随着负荷的升高呈增大趋势,机组负荷越高,由减温水变化导致的机组出力下降越多。     

某660MW超超临界锅炉吹灰系统减温水调节阀工作异常分析

某电厂660MW超超临界锅炉在吹灰过程中存在吹灰蒸汽温度投自动时减温水调节阀频繁波动且调节阀磨损严重的问题。本文首先对该工程吹灰系统设计减温水系统的必要性进行了分析,其次对锅炉吹灰过程中蒸汽温度投自动时减温水调节阀频繁波动,调节阀磨损严重等问题进行了原因分析并提出了相应的改进措施。     

Numerical analysis of Chevron nozzle effects on performance of the supersonic ejector-diffuser system

The supersonic nozzle is the most important device of an ejector-diffuser system.The best operation condition and optimal structure of supersonic nozzle are hardly known due to the complicated turbulent mixing,compressibility effects and even flow unsteadiness which are generated around the nozzle extent.In the present study,the primary stream nozzle was redesigned using convergent nozzle to activate the shear actions between the primary and secondary streams,by means of longitudinal vortices generated between the Chevron lobes.Exactly same geometrical model of ejector-diffuser system was created to validate the results of experimental data.The operation characteristics of the ejector system were compared between Chevron nozzle and conventional convergent nozzle for the primary stream.A CFD method has been applied to simulate the supersonic flows and shock waves inside the ejector.It is observed that the flow structure and shock system were changed and primary numerical analysis results show that the Chevron nozzle achieve a positive effect on the supersonic ejector-diffuser system performance.The ejector with Chevron nozzle can entrain more secondary stream with less primary stream mass flow rate.     

核电厂用超高分子量聚乙烯喷嘴研发与应用

  目的  为解决核电厂核安全3级循环水过滤系统（CFI）喷嘴冲刷磨蚀及腐蚀问题，采用超高分子量聚乙烯(UHMWPE)开发了一种耐腐蚀、耐磨的喷嘴。  方法  通过对重要加工工艺参数测试，固化了喷嘴制造加工工艺，为验证所开发的喷嘴耐磨性及水力性能，进行材料本体耐磨试验，并模拟核电厂运行条件开展基于研发产品的冲刷和水力试验。  结果  试验结果表明:UHMWPE喷嘴的耐磨性能优异，高于传统材料；可以适应核电厂高速冲刷的需求，水力性能亦可满足核电厂的要求。  结论  UHMWPE喷嘴投入运行一年半，经持续运行，喷嘴未发现冲刷变形和腐蚀现象，运行效果优异。因此，采用超高分子量聚乙烯材料制备核电厂CFI系统喷嘴是可行的，可替代原有的进口尼龙喷嘴。     

Thermo-mechanical simulation for nozzle header of once-through steam generator by experiment and finite element method

The thermo-mechanical behaviour of the nozzle header of a steam generator developed for an integral reactor was investigated using experimental and finite element methods. The nozzle feedwater header suffers from severe thermal transient loadings during the operation of the nuclear reactor. The nozzle header is exposed to the low temperature inlet feedwater and the high temperature outlet superheated steam and the other side of the nozzle header contacts with the high temperature primary coolant. The temperature gradients result in high thermal stresses in the nozzle header. The thermal transient loading has been simulated in a test loop. The input and thermo-hydraulic parameters of the primary and the secondary system were. Strain gauges and thermocouples attached to the highly stressed region monitored the thermo-mechanical behaviour of the nozzle header. In parallel with the experimental study, the transient behaviour of the nozzle header was simulated by utilizing a commercial finite element code. The fluid temperature and pressure obtained from the test loop were used as inputs to the finite element analysis. As a result of this investigation, the thermo-mechanical load carrying capacity of the developed steam generator nozzle header was proved numerically and experimentally.     

A study of the influence of air-knife tilting on coating thickness in hot-dip galvanizing

Gas wiping is a decisive operation in hot-dip galvanizing process. In special, it has a crucial influence on the thickness and uniformity in coating film, but may be subsequently responsible for the problem of splashing. The progress of industry demands continuously the reduction of production costs which may relate directly with the increase of coating speed, and the speed up of coating results in the increase of stagnation pressure in gas wiping system in final. It is known that the increase of stagnation pressure may accompany a harmful problem of splashing in general. Together with these, also, from the view point of energy consumption, it is necessary to design a nozzle optimally. And there is known that the downward tilting of nozzle using in air knife system is effective to prevent in somewhat the harmful problem of splashing. In these connections, first, we design a nozzle with constant expansion rate. Next, for the case of actual coating conditions in field, the effects of tilting of the constant expansion rate nozzle are investigated by numerical analysis. Under the present numerical conditions, it was turned out that the nozzle of constant expansion rate of p = having a downward jet angle of 5° is the most effective to diminish the onset of splashing, while the influence of small tilting of the nozzle on impinging wall pressure itself is not so large.     

水煤浆气化喷嘴温度场和热应力分布的数值模拟及分析

采用数值模拟的方法,对水煤浆气化炉内热态温度场及喷嘴头部温度分布进行了分析,结果表明:增加冷却水流量和加大冷却水旋流强度可以有效降低喷嘴头部温度.同时,利用有限元分析法对喷嘴头部进行了热应力耦合计算,分析了其热应力变化特性,结果表明:喷嘴圆角处热应力比较集中,采用冷却水旋流流动后,该处温度降低,热应力集中的现象得到缓解,可提高喷嘴的使用寿命.     

共轨系统小压力室喷油嘴喷雾特性

柴油机喷油嘴是燃油系统和燃烧室之间的关键接口,对燃油雾化非常重要．设计加工了喷雾需要的单孔喷油嘴,检测了喷孔的入口和出口尺寸．喷油嘴经过液体挤乐研磨处理,并测试了喷油嘴在挤压研磨前后10MPa下的高斥流量．液体挤压研磨能够提高流量系数10％～15％．测得给定工况下试验喷油嘴的喷油规律和针阀升程,用Matlab编程得到的...     

Exergy analysis of two-phase steam–water injector

Exergy analysis is used as a tool for the evaluation of exergy losses in a two-phase steam–water injector in an effort to improve its overall performance in respect to exit pressure. The aim of this paper is to study irreversible losses in the component parts of the injector, including the steam nozzle, water nozzle and diffuser as well as the two-phase region comprising the mixing chamber and the condensation shock wave. Calculations based on experimental data revealed the regions with the greatest irreversibilities, namely in the two-phase region and in the steam nozzle. Particular attention was paid to the steam nozzle, for which a procedure was developed to determine the overall velocity coefficient, including all irreversibilities in the steam nozzle during steam expansion. The study indicated the most important factors influencing the injector’s performance. Finally, the exergy efficiency was calculated for the two investigated steam injectors.     

考虑部分进汽影响的调节级变工况特性研究

部分进汽的存在影响机组运行经济性.以某600 MW喷嘴配汽方式汽轮机机组为例,基于量纲分析理论,分别将全开调节阀及半开调节阀后喷嘴组压比简化表示为流量比的函数,提出一种适用于喷嘴配汽方式汽轮机调节级变工况计算模型,并研究分析了部分进汽对调节级内压比的影响;应用所提出的模型,探讨了重叠度的存在对阀门流量特性和机组热经济性评价指标的影响,为喷嘴配汽方式汽轮机机组运行优化研究提供了参考.     

An experimental study on the organic Rankine cycle to determine as to how efficiently utilize fluctuating thermal energy

Thermal properties of the available energy such as maximum temperature and thermal energy capacity are greatly influenced to the design of energy conversion system like the organic Rankine cycle (ORC). Useful thermal energy can be obtained from: waste heat energy, geothermal energy, solar heat energy, biomass energy, and so on. However, these cannot usually be supplied at constant levels. Hence, the temperature and flowrate of the thermal energy can vary while the ORC is working. In order to efficiently utilize such fluctuating thermal energy, an experimental study was conducted while adjusting the mass flowrate and the temperature of the working fluid. Three supersonic nozzles and an impulse type turbine were applied. The supersonic nozzle was adopted to increase the spouting velocity for efficient operation of the impulse turbine. The nozzle was designed to reach a velocity of Mach 1.6 at the nozzle exit, and three nozzles were used to control the mass flowrate in this experiment. The experimental results were compared with the predicted results obtained by the cycle analysis.     

炉内喷钙脱硫技术的工业应用研究

介绍了两台10t/h链条炉配套的脱硫工程和测试结果,脱硫系统包括结合四角旋涡燃烧技术的炉内喷钙和尾部利用文丘里喷嘴和麻石水膜除尘器对脱硫剂加湿活化两部分。测试结果表明,引入四角旋涡二次风技术可以在不影响锅炉运行的情况下明显改善脱硫剂在炉膛内的混合煅烧,有利于提高炉内脱硫效率,利用文丘里水喷嘴和除尘器,对未反应的氧化钙颗粒进行活化,提高脱硫反应速度,事以在较低钙与硫比下实现较高脱硫效率。对原配有文丘里水喷嘴和麻石水膜除尘器的工业锅炉进行脱硫环保改造时,炉膛喷钙尾部增湿活化脱硫技术具有明显的技术经济优势。