火电厂锅炉运行优化目标值计算方法的研究.pdf

热力发电 200609 27 收稿日期 20060525 火电厂锅炉运行优化 目标值计算方法的研究 吴智群1,王顶辉2,黄廷辉1,胡洪华1,吴 涛1 1. 西安热工研究院有限公司,陕西 西安710032 ;2.中电国华电力股份有限公司,北京100025 [摘 要] 通过分析锅炉运行目标值的影响因素,指出运行目标值可分为直接运行参数和间接性能参数 两类;提出了间接性能参数目标值的计算方法,并通过某电厂600 MW机组运行优化管理系统的实际应 用,给出了直接运行和间接性能两类参数的耗差计算方法。应用结果表明,两类参数对煤耗的影响量一 致,可用于锅炉性能监测和诊断。 [关键词] 火电厂;锅炉;运行优化;耗差分析;目标值;计算方法 [中图分类号]TM621. 4 [文献标识码]A [文章编号]10023364200609002703 火电厂锅炉运行的经济性与锅炉的设计、 负荷、 煤 质、 环境、 运行管理和操作水平等诸多因素有关。正确 确定热力参数的目标值,才能有效进行设备的耗差分 析,从而为优化运行提供理论指导。目前锅炉运行优 化目标值的确定主要依据制造厂的设计值、 优化运行 试验值、 运行参数的历史统计值或变工况热力计算而 定。锅炉实际运行时的煤质与环境条件往往偏离设计 工况,优化运行试验仅可在某种特定条件下进行,不适 用于锅炉的全工况分析。虽然根据运行参数的历史统 计值和变工况热力计算确定的目标值能适应锅炉运行 优化耗差分析的需求,但是由于锅炉运行参数间的耦 合性导致各运行优化目标值之间也存在相关性,使得 耗差分析计算中各相关因素引起的耗差不吻合。为 此,本文提出锅炉运行优化目标值的相关性确定方法, 以使锅炉的耗差分析计算科学实用。 1 影响运行优化目标值的因素 影响锅炉设备运行的热力参数很多,但是从理论 上来说,当锅炉的热负荷、 煤质和环境一定后锅炉的性 能是确定的,即锅炉的热力参数具有负荷特性、 环境特 性和煤质特性[1]。 1实际运行中锅炉的热负荷是不断变化的,在不 同的热负荷条件下,锅炉的性能和热力参数变化较大, 因而,锅炉运行参数的目标值是不相同的。2制造厂 设计锅炉时依据设计煤种确定锅炉的本体结构,而实 际运行时由于来煤的多样性,实际燃烧的煤种与设计 煤种不同,导致锅炉的燃烧性能和经济性与设计状况 不同,即锅炉运行参数的目标值随燃烧煤种而变化。 3当外界环境温度变化时进入锅炉边界的热力参数 发生变化,从而锅炉运行与输出边界上的热力参数也 跟随变化,即锅炉运行参数的目标值随环境温度的变 化而变化。 总之,对于给定的锅炉,影响运行目标值的因素为 负荷、 煤质和环境温度,即 Tf D , M , t1 式中T为运行参数目标值; D为负荷; M为煤质; t为 环境温度。 2 运行目标值的计算方法 在机组的耗差分析计算中,锅炉方面影响供电煤 耗率的直接运行参数主要有排烟温度、 排烟氧量、 飞灰 含碳量;间接性能参数有排烟损失、 机械未完全燃烧损 技术交流 28 热力发电 200609 失、 锅炉效率等。由于直接运行参数影响间接性能参 数,需要考虑两类参数间的耦合关系,而直接运行参数 与间接性能参数目标值的确定方法不同。 排烟温度、 排烟氧量、 飞灰含碳量等直接运行参数 的目标值可采用变工况热力计算确定[1]。当锅炉的本 体结构一定时,对不同负荷、 煤质、 环境条件在设计工 况基础上进行变工况的热力校核计算,可以得到排烟 温度等运行参数的离散三维曲面簇,将它们作为直接 运行参数的目标曲线簇,则应用两次插值法即可求出 不同负荷、 煤质、 环境温度时排烟温度等的目标值。 依据文献[2] ,排烟损失、 机械未完全燃烧损失是 燃料发热量、 排烟温度、 送风温度、 排烟氧量、 飞灰含碳 量和煤种的函数,其中q2、q4的计算公式见式2、 式 3。 q2 K 1K2 α tpy-tsf 100 2 q4 33 727Aar Qnet 90Cfh 100 -Cfh 100Clz 100 -Clz 3 式中 q2 排烟损失; q4 机械未完全燃烧损失; tpy 排烟温度; tsf 送风温度; α 排烟过量空气系数; Qnet 低位发热量; Cfh,Clz 飞灰与炉渣含碳量; Aar 收到基灰分; K1,K2 与煤种有关的系数。 由于耗差分析计算是基于相同的环境温度与相同 的煤质条件进行的,因此,以实际环境温度和实际燃烧 煤质以及在其基础上确定的排烟温度、 排烟氧量、 飞灰 含碳量的目标值代入排烟损失、 机械未完全燃烧损失 的计算公式式2、 式3 ,以求得排烟损失、 机械未 完全燃烧损失在实际状态下的目标值,即 q2 ,TfQnet,tpy ,T,tsf,O2py ,T4 q4 ,TfQnet,Cfh ,T,Clz,Aar5 式中 q2, T 排烟损失在实际状态下的目标值; q4, T 机械未完全燃烧损失在实际状态下的 目标值; tpy ,T 排烟温度在实际状态下的目标值; O2py ,T 排烟氧量在实际状态下的目标值; Cfh ,T 飞灰含碳量在实际状态下的目标值。 同理,以实际状态下的排烟损失、 机械未完全燃烧 损失的目标值代入锅炉效率的计算公式即可求得锅炉 效率在实际状态下的目标值 ηTf q2, T, q4, T, q5, q3,q66 式中q3为可燃气体未完全燃烧损失;q5为散热损失; q6为灰渣物理热损失。 3 实际应用和分析 在平圩电厂运行优化系统中采用了本文研究的计 算方法。该厂1号锅炉是HG1025/ 18. 2M型亚 临界压力一次中间再热自然循环汽包炉,煤质设计参 数如表1 ,设计环境温度20℃,给水温度270℃,主蒸 汽流量1 025 t/ h ,排烟温度未修正 136 ℃。 表1 煤质特性 项目数值 收到基碳Car/ 60. 17 收到基氢Har/ 2. 83 收到基氧Oar/ 2. 40 收到基氮Nar/ 0. 98 收到基硫Sar/ 1. 20 收到基水分Mar/ 7. 03 收到基灰分Aar/ 25. 39 收到基低位发热量Qnet ,ar/ kJkg- 123 003 改变负荷、 环境温度、 煤种对该锅炉进行变工况热 力计算,可以得到排烟温度、 排烟氧量、 飞灰含碳量的 目标曲线簇。图1、 图2是排烟温度在不同煤质条件 时的目标曲线簇。 图1 Qnet,ar为23 042 kJ/ kg时排烟温度目标曲线簇 以式4～式6确定相应负荷点的排烟损失、 机 械未完全燃烧损失、 锅炉效率目标值及耗差计算列于 表2。由表2的计算结果可见,在4种不同运行工况 下,排烟损失和机械未完全燃烧损失引起的耗差之和 技术交流 标准分享网 w w w .b z f x w .c o m 免费下载 热力发电 200609 29 图2 Qnet,ar为19 013 kJ/ kg时排烟温度目标曲线簇 与锅炉效率偏差引起的耗差基本相等,间接性能参数 引起的耗差与锅炉效率引起的耗差的相对误差基本为 零,能够很好地吻合。直接运行参数偏差引起的耗差 之和与锅炉效率偏差引起的耗差相差很小,最大相对 误差为2. 55 ,能满足工程精度要求。从物理意义上 分析,造成该偏差的原因是由于锅炉耗差计算方法[3] 中Δ O2pyΔtpy 、 Δ O2pyΔtpyΔCfh等的相互影响引起的煤耗 偏差忽略未计;而从数学意义上分析,它是由于级数项 数的选取造成的,将级数项数取为3时可以消除该偏 差,实际应用中选取的级数项数应视工程精度要求而 定。 表2 锅炉在不同负荷时的耗差分析表 ① 项目 工况1 实际目标耗差② 工况2 实际目标耗差② 工况3 实际目标耗差② 工况4 实际目标耗差② 排烟氧量/ 5. 45. 83- 0. 75. 125. 83- 0. 995. 35.5- 0. 265. 15. 5- 0. 46 排烟温度/℃1281201. 987138125. 72. 671301162. 4951381321. 05 飞灰含碳量/ 2. 22. 6- 0. 62. 82. 630. 2572. 72.50. 252. 752. 50.308 直接运行参数总耗差/ g kW h - 1 0. 6871. 9372. 4850.898 Q2损失/ 7. 1786. 81. 3756. 455. 971. 7285. 985. 352. 245. 335.150.613 Q4损失/ 1. 31. 49- 0. 671. 561. 490. 2561. 251. 180. 251. 271.180.307 间接性能参数总耗差/ g kW h - 1 0. 7051. 9842. 490. 92 锅炉效率/ 90. 290. 390. 70590. 6791. 221. 98591.492.152. 4992. 0892. 340. 92 直接运行参数总耗差 与锅炉效率耗差误差/ 2. 552. 410. 22. 39 间接性能参数总耗差 与锅炉效率耗差误差/ 00. 000 500 ① 耗差分析表中的工况见表3 ;② 耗差单位为g/ kW h 。 表3 耗差分析表涉及的工况 项目工况1工况2工况3工况4 负荷/ MW252252301301 环境温度/℃10. 2311132 Qnet ,ar/ kJkg- 119 01319 01323 04223 042 4 结 论 1锅炉运行优化的目标值分为直接运行参数和 间接性能参数。其目标值的计算方法不同,直接运行 参数可采用锅炉变工况校核热力计算确定,它是负荷、 环境温度、 煤质的函数;间接性能参数可采用本文提出 的基于参数目标值的计算方法,其目标值与直接运行 参数目标值有函数关系。 2虽然直接运行参数和间接性能参数目标值的 计算方法不同,但采用本文提出的计算方法可使其对 煤耗的影响量吻合一致,最大误差小于3 ,完全满足 工程实际应用要求。 3本文提出的锅炉直接运行参数和间接性能参 数耗差计算方法可以应用于电站锅炉性能监测和诊 断,对指导锅炉的优化运行具有实际意义。 [参 考 文 献] [1] 杨军华.一种确定锅炉运行参数基准值的新方法[J ].热 力发电,1999 ,2 . [2] GB1018488 ,电站锅炉性能试验规程[S]. [3] 吴智群.电站锅炉性能诊断与优化分析偏增量法的研究 [J ].热力发电,2003 ,5 . 技术交流 THERMAL POWER GENERATION Vol. 35 No. 9 Sep. 2006 Contents 2 under same designed parameters , the ICGCC system with fluidized bed gasifier of lower temperature and that with air flow bed gasifier of higher temperature each has its strong and weak points , it is recommended to use fluidized bed gasifier for ICGCC system allocated with low tempera2 ture rough coal gas purification system; 3 during the process of of designing ICGCC system , the inlet temperature of gas turbine should chose a high value as possible. there is an optimal pressure ratio value corresponding to the said temperature ; 4 the power supply efficiency of ICGCC system to be 5～7 percentage point higher than that of a conventional power plant. Key words ICGCC; power generating system; concept design; perance analysis; using air for gasification; gasifier ADVANCEMENT OF THEORETIC STUDY ON RIJKE TUBE AND COMBUSTION FACILITY THEREOF LIUYunfang, CHENGLeming, ZHENG H aixiao et al4 ⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ ⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract The theoretic model of Rijke tube and related facility has been analysed and summarized. The model is classified into three types , namely the qualitative one , the phenomenological one , and the basic one. Explanation of analytic for the three said model types has been carried out with examples , and the development of finding the solution for mathematical models being induced. At the same time , the main problems lying ahead estab2 lishing model for the pulsating fluidized bed combustion technology have been pointed out. Key words Rijke tube ; pulsating burner ; mathematical model ; fluidized combustion OPTIMAL DISTRIBUTIONOF FEEDWATER ENTHALPY RISE IN THE REGENERATIVE SYSTEM BASED ON MASS UNIT MA2 TRIX ANALYTICAL CHEN H aiping, LIN Anfei, WU Junfeng 11⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract On the basis of mass unit matrix analytical , taking thermal system of steam powergeneration unit as study object , a new of feedwater enthalpy rise distribution in regenerative system has been put forward through vigorous mathematical deduction. By using the new meth2 od , the approximate behavior and hypothetical conditions in traditional have been eliminated , and empirical correction factor needn’t to be a2 dopted , making the calculation to have more reality , and making the distribution result to be more objective. Key words heater ; regenerative system; feedwater enthalpy rise ; mass unit ; matrix analysis TEST STUDY ON FLOW BEHAVIOROF GASSOLID TWOPHASE FLOW THROUGH A HORIZONTAL DIFFUSER RUAN Xiaodong, ZHAO Wenfeng 15 ⋯⋯⋯⋯ ⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract In order to study the flow behavior of gassolid twophase flow through a horizontal diffuser , the flow situation of gassolid twophase flow with defferent size solid particles , different gas flow rate , and different inlet position of the particles has been measured by using particle image vilocimetry PIV technology. It is found from the test that the gas velocity was obviously accelerated with the existence of solid particles after the crosssection in diffuser to be expanded , and only the solid particles with a definite size can make the gas to have higher velocity. For the same flow rate , the inlet position of solid particles can also greatly affect the flow velocity of particles in the pipeline. Key words gassolid twophase flow ; flow behavior measurement ; PIV ; twophase interaction ; pneumatic conveying DESIGN AND OPERATION OF 480 t/ h CFB BOILERBAO Shaolin , LΒQinggang, NA Yongjie et al18⋯⋯⋯⋯⋯⋯⋯⋯ Abstract The 480 t/ h circulating fluidized bed CFB boiler developed jointly by the Engineering Thermophysics Research Institute under The Chinese Academy of Sciences and Huaguang Boiler Co Ltd , Wuxi City of Jiangsu Province , has been put into operation at Huadian Wuda Thermal Power Co Ltd. operation shows that the said boiler has features , such as high combustion efficiency , stable perance , and good reliability. The structure de2 sign and operation situation of said boiler have been presented , and existing problems being pointed out. Key words CFB boiler ; cyclone separator ; drum type slagdischarging machine ; ash deposition; wornout CAUSE ANALYSIS FOR SOMEWHAT LOW INDICATING VALUE OF THE FLAME DETECTOR OR MISJUDGEMENT OF THE VALUE AND RESOLVINGMEASURES THEREOFWANGChunchang, YANGShumin , ZHANGYizheng et al21⋯⋯⋯⋯ Abstract The causes leading to somewhat low indicating value of the flame detector for very few burners in coalfired utility boiler or misjudgement of the value have been analysed , and resolving measures , such as adjusting the detection distance of the flame detector , eliminating shield of vision for the flame detector , revising the critical value and background uation etc. , being put forward. Practice of application on two boilers in Rizhao Power plant shows that the adjustment of detection distance not only can solve the problem of somewhat low indicating value for very few flame detectors , but also can save large amount of fuel oil used for stabilizing combustion , having remarkable economic benefit under condition of stable ignition and com2 bustion for pulverized coal and air flow. Key words boiler ; burner ; flame detector ; indicating value ; detection distance APPLICATIONOF PLASMA OILLESS IGNITION TECHNOLOG Y IN BLOWING PIPES WITH STEAM FOR ONCETHROUHG BOILEROF 600 MW SUPERCRITICAL UNITZHANG Xiangqun , SUN Wei, YIE Zhenqi et al24⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract Full process oilless ignition and pipeblowing for oncethrough boiler of 600 MW supercritical unit in Huaneng Shantou Power Plant has been realized by using plasma oilless ignition technology , control of temperature up and pressure rise for the unit to be stable and simple. Compared with traditional mode of putting oil into service to carry out pipeblowing , the plasma oilless ignition can save capital investment about 2. 63 million yuan during the entire pipeblowing process , economic benefit being most remarkable. Key words 600 MW supercritical unit ; oncethrough boiler ; plasma ignition ; pipeblowing with steam; momentum ratio STUDY ON CALCULATION FOR TARGET VALUE OF BOILER OPERATION OPTIMIZATION IN THERMAL POWER PLANTSWU Zhiqun , WANGDinghui, HUANG Tinghui et al27⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract Through analysis of affecting factors for the target value of boiler operation optimization , it has been pointed out that the target value of oper2 ation optimization can be classified into two kinds , namely direct operation parameters and indirect perance parameters. The calculation of target value for indirect perance parameters has been put forward , and through practical application of the operation optimization management sys2 标准分享网 w w w .b z f x w .c o m 免费下载 tem for 600 MW unit in one power plant , the calculation of consumption difference between two kinds of parameters , i. e. direct operation pa2 rameters and indirect perance parameters , having been given. Results of application show that the influence of two kind parameters upon the coal consumption is identical , it can be used for supervisory and diagnosis of the boiler perance. Key words thermal power plant ; boiler ; operation optimization; consumption difference analysis; target value ; calculation ENERG YSAVING AND CAPACITYINCREASING RETROFIT OF STEAM TURBINE FOR 100 MW UNIT IN HUAYINSHAN POWER PLANTZHUYun 30⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract The retrofit and construction situation of flow passage for highpressure and lowpressure cylinders , bearings , and governing system of turbine no. 3 in Huayinshan Power Plant have been presented. After retrofitting , specific heat consumption of said unit has decreased 453. 6 kJ/ kWh , output capacity increased 10 MW. Key words 100 MW unit ; steam turbine ; highand lowpressure cylinder ; bearing; governing system; energysaving ad capacityincreasing retrofit JUDGEMENT OF IMPACTRUBBING TROUBLE IN STARTUP PROCESS OF 135 MW UNIT AND REMEDIAL MEA2 SURES THEREOFWU Weiji 33⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract Compared with the unit taking basic load , the peakregulating units are more easily subject to hot and cold impact , hence , the problem of vi2 bration is easier to occur on them. The main causes leading to abnormal vibration in startup process have been analysed , and judgement for vibration trouble resulting from impactrubbing , as well as remedial measures for avoiding expansion of said trouble being given. Key words 135 MW unit ; peakregulating operation ; impactrubbing trouble ; rubbing vibration ANALYSIS OF SERVOMOTOR AND OILPIPE VIBRATION FORCN635/ 9 STEAM TURBINE, AS WELL AS REMEDY THERE2 OFYANG G enshan 35⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract After putting CN635/ 9 steam turbine unit of Nanjing Chemical Industry Co into operation , serious vibration of the servomotor and oil pipe in the governing system had occurred. For this , the causes leading to vibration has been analysed , and corresponding remedial measures being taken , finally , the vibration having been eliminated. Key words steam turbine ; governing system; servomotor ; vibration APPLICATIONOF BP NEURAL NETWORK FOR MONITORINGMATERIAL’S LEVEL IN BALL MILLS TAO Min, LI Ying, WANGSiyi 37 ⋯⋯⋯⋯⋯⋯⋯⋯⋯ ⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract Effectively monitoring and controlling the material’s level in ball mills , are the key for optimizing operation , energysaving , and consump2 tionreducing of the coal pulverizing system. Directing against operation features of ball mills , a BP neural network model has been established to classify a variety of parameters under various working conditions in operation , and the adaptive monitoring of material’s level being realized. The re2 sults of emulation show that the said neural network has good effectiveness , laying a foundation for optimized operation and automatic control of the coal pulverizing system. Key words ball mill ; material’s level monitoring; BP neural network; control DEBUGGINGOF DEH GOVERNINGSYSTEM FOR 600 MW SUPERCRITICAL UNIT IN HUANENG QINBEI POWER PLANT AND CONTROL IMPROVEMENTWANG Xiaoyong, GAO H aidong, SHI zhangfeng et al40⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯⋯ Abstract The causes leading to problems discovered in control system during the process of debugging for digital electrohydraulicDEH governing system of