火电厂循环水处理水质稳定剂阻垢性能评价方法的研究

1、火电厂循环水处理水质稳定剂阻垢性能评价方法的研究姜琪 ,闫锟 ,许建学(国电热工研究院 ,陕西 西安710032)目前 ,水质稳定剂 (水稳剂) 种类很多 ,且不断有新产品诞生 ,它们的应用性能 (主要包括阻垢和缓蚀性能) 千差万别 。水稳剂的应用性能受原水水质的影响很大 , 目前还只能通过试验判别 。为合理选用水稳剂 ,除常规 的理化性能检测外 ,还需从应用角度对其进行评价 。长期以来 ,对于水稳剂阻垢性能的评价 ,电力行业 没有统一的方法 ,因而均参照或采用国内外其它行业 的标准 ,其中使用较广泛的为静态阻垢率测定法 。但 在实践过程中 ,人们发现此法有许多不足之处 ,尤其是 测得的各种水

2、稳剂的阻垢率非常接近 ,不易分辨它们 阻垢性能的优劣 ; 而其它行业标准使用条件也与电力 行业不尽相同 。目前 ,国内电力行业使用较多的阻垢 性能评价方法还有极限碳酸盐硬度法 ,该方法具有分 辨率高 ,数据重现性好 ,指导意义明确 ,简单实用等优 点 ,更适合电力行业的实际运行情况 。该法经在电厂 运行中反复验证 ,已趋成熟 ,但它最大的缺点在于试验 时间过长 。为此 ,对该方法的试验装置作了改进 ,采用 强化循环喷淋的方式来浓缩试验水样 。这样 ,既模拟 了实际运行情况 ,又使试验时间大为缩短 。本文重点 介绍采用极限碳酸盐硬度法 (改进装置) 对水稳剂阻垢性能进行评价的方法 ,并与阻垢率法

3、1 进行了比较 。1试验方法试验装置及条件原试验装置见图 1 ,改进后的试验装置见图 2 。本 试验采用改进后的试验装置 。试验条件 :(1) 试验用水为电厂循环冷却系统补充水或配制 水 ;(2) 试验温度 45 1 ,根据实际需要也可选 用其它温度 ;(3) 水稳剂浓度采用 2 . 0 mg/ l ( 有效固体含量) ,也可根据电厂实际需要选用其它浓度 ;(4) 每小时的循环水量和水容积比为 15 20 ,也 可根据实际情况选用其它值 。1 . 11 . 2阻垢性能的测定本方法采用恒温恒容浓缩法 。直接使用电厂循环 冷却系 统 补 充 水 ( 或 含 有 一 定 量 ca ( hco3 )

4、2 的 配 制 水) 和 水 稳 剂 制 备 成 试 液 ( 水 稳 剂 浓 度 2 mg/ l ) , 取15 l 此试液置于有机玻璃箱中 ,加热升温至 45 ,并使温度保持在 45 1 ,同时启动循环泵使溶液循作者简介 : 姜琪 ( 1969 ) ,男 ,西北大学硕士研究生毕业 ,现为国电热工研究院化学工程技术中心高级工程师 ,主要从事水处理技术的研究开发工作 。 摘要 介绍采用极限碳酸盐硬度法 ( 改进装置) 对水质稳定剂阻垢性能进行评价的方法 ,包括阻垢性 能测定和评价指标 、试验水温 、水质稳定剂浓度 、试验装置循环水量等的确定 ,并与阻垢率法进行了比较 。 实验表明 ,极限碳酸盐硬

5、度法具有分辨率高 、数据重现性好 、指导意义明确 、简单实用等优点 ,适用于火电 厂循环冷却水处理水质稳定剂阻垢性能的评价 。 关键词 火电厂 ;循环冷却水 ;水处理 ;水质稳定剂 ;阻垢性能评价 ;极限碳酸盐硬度法 中图分类号 tm621 . 8 文献标识码 a 文章编号 10023364 (2004) 06006203水稳剂的阻垢性能 ,而且能区分复配水稳剂的阻垢性能 。(2) 数据的重现性好 。(3) 物理意义明确 。即在一定条件下 ,加入水稳剂 维持运行中不结垢所能达到的最大碳酸盐硬度值即极 限碳酸盐硬度值 ,与之对应的浓缩倍率即为极限浓缩 倍率 。在一定条件下 ,便于对各种水稳剂的极

6、限浓缩 倍率进行直接的定量比较 ,有较强的实用意义 ;电厂选择水稳剂时直观 ,更加贴近运行实际 。图 1 静态极限碳酸盐硬度试验装置示意2 . 2试验温度的确定一般情况下 ,水温在 50 以上时 ,水垢的附着速 度开始增大 。另外 ,随着水温的不断增高 ,水稳剂的阻 垢效果也不断降低 ,当试验温度超过 45 时 ,极限浓 缩倍率开始快速下降 ( 图 3) ; 而在 45 以前 ,极限浓 缩倍率变化不明显 。通常 ,我国电厂凝汽器出口最高水温不超过 45 。因此将试验温度确定为 45 。图 2 改进后的试验装置示意环喷淋 ,并由下口瓶不断补水 (补水中水稳剂浓度也为2 mg/ l ) ,使箱中溶

7、液恒温恒容浓缩 。在浓缩过程中 , 定期从箱中取样 50 ml ,测定溶液中的 cl - 及总碱度 (试验初期 ,间隔时间可长些 ,试验后期 ,间隔时间宜短 些) 。当 a 0 . 2 时停止运行 。这时溶液的碳酸盐 硬度值 ,即为极限碳酸盐硬度值 ,据此可计算出极限浓 缩倍率 。测得的极限浓缩倍率越高 ,则同等条件下该 水稳剂的阻垢性能越好 。该指标乘以 0 . 80 . 85 即可作为循环 冷 却 系 统 实 际 运 行 控 制 指 标 。文 中 a 为试验水 质 : 全 碱 度 2 . 60 mmol/ l , 氯 离 子 54 mg/ l , 总 硬 度 4 . 7mmol/ l ,

8、钙硬度 3 . 0 mmol/ l , 水稳剂浓度 2 . 0 mg/ l 。图 3 温度对阻垢性能的影响3 . 3水稳剂浓度的确定水稳剂的阻垢效果与其使用剂量有一定关系 。一 些常见的水稳剂的极限碳酸盐硬度与水稳剂浓度的关系见图 4 。c1 - 浓缩倍率 kcl 与总碱度浓缩倍率ka 的 差 值 , 即a = cl - cl - j d j d ,式中 c1 -与 j d 为箱内x bx bxxc1 - 浓度和总碱度 , c1 - 与 j d 为补水中的 c1 - 浓度bb和总碱度 。2 阻垢性能评价方法的研究2 . 1阻垢性能评价方法及指标的确定目前 ,对水稳剂阻垢性能的评价方法主要有 :

9、 ( 1)阻垢率法1 。(2) 鼓泡法2 。(3) 极限碳酸盐硬度法 。 本文采用极限碳酸盐硬度法中的极限浓缩倍率作 为评价指标 (作为工业冷却水系统控制指标须乘以系数 0 . 80 . 85) ,其主要原因如下 :(1) 该法分辨率高 ,不仅能区分不同类型 、同一系列系列 1 a tm p 系列 2 ed tm p 系列 3 hed p 系列 4 聚丙烯酸 系列 5 三聚磷酸钠 系列 6 六偏磷酸钠 。试验水质 :p h 7 . 6 , 总硬度 3 . 6 mmol/ l , 钙硬度1 . 4 mmol/ l , 碱度3 . 2 mmol/ l , 氯离子 12 mg/ l ; 试验温度 4

10、5 1 。图 4 不同水稳剂的稳定效果63热力发电2004 (06)由图 4 可见 ,随着水稳剂浓度的增高 ,其阻垢能力增加 ,循环水极限碳酸盐硬度值也随之增加 。大部分 水稳剂 (除聚丙烯酸外) ,在补充水中浓度增加到一定 程度时 (大于 5 mg/ l ) ,循环水的极限碳酸盐硬度值增 加缓慢 ,并渐趋稳定 。考虑到电厂实际运行成本等经 济因素 , 确 定 循 环 水 补 充 水 中 水 稳 剂 的 浓 度 为 2 . 0 mg/ l (有效固体含量) ,实际试验中也可根据电厂实际情况和要求进行确定 。率要高于阻垢率法 。3 . 5 . 2不同公司同种产品的比较atmp a ,atmpb

11、,atmp c 分别为 a ,b , c 3 家公司 生产的 atmp ,用极限碳酸盐硬度法测定各药剂的阻垢 性能 ,并与阻垢率法进行比较 ,结果如表 3 和表 4 。表 3 极限碳酸盐硬度法试验结果补充水中水稳剂 含量/ mg l - 1极限浓 缩倍率极限碳酸盐 硬度/ mmol l - 1水稳剂种类a tm paa tm pb3 . 03 . 02 . 862 . 5411 . 09 . 82 . 4循环水量的确定“工业企业循环冷却水处理设计规范”中规定 ,循 环冷却系统的循环水流量 ( q ) 和水容积 ( v ) 的比 ( q / v ) 一般选用 35 。该比值越大 ,系统浓缩越快

12、,即达 到某一浓缩倍率的时间就越短 。采用改进后的试验装 置 (图 2) 进行试验时 ,循环水流量过大 ,易造成水喷溅 和水蒸汽携带盐分 。结合实际经验 ,并考虑减少浓缩时间 ,循环水流量体积比 ( q / v ) 选为 1520 。 a tm pc 3 . 0 2 . 44 9 . 4 试验水 质 : 全 碱 度 3 . 85 mmol/ l , 全 硬 度 4 . 40 mmol/ l , 钙 硬 度3 . 15 mmol/ l ,氯离子 16 . 5 mg/ l ;试验温度 45 1 ;水稳剂浓度 2 mg/ l 。表 4 阻垢率法试验结果原水中钙离子/ mmol l - 1过滤水中钙离

13、子/ mmol l - 1水稳剂阻垢率/ %a tm paa tm pb10 . 010 . 08 . 07 . 78077 a tm pc 10 . 0 7 . 6 76 原水组分 : cacl2 10 mmol/ l , mgso4 3 mmol/ l , na hco3 10 mmol/ l ;水稳剂浓度 2 mg/ l ;试验温度 80 1 ;试验时间 6 h 。2 . 5分辨率2 . 5 . 1同类水稳剂的比较 用极限碳酸盐硬度法对同类水稳剂的阻垢性能进行了试验 ,并与阻垢率法进行了比较 ,结果见表 1 和表 2 。表 1 极限碳酸盐硬度法试验结果表 3 和表 4 结果表明 ,阻垢率

14、法测得的结果明显难以区分 3 种药剂阻垢性能的优劣 。而极限碳酸盐硬 度法则可以容易地分辨出它们之间的差别 。如果以 a 公司产品为比较基准 100 % ,则用 2 种方法测得结果 的相对值如下 :(1) 极限碳酸盐硬度法 ab c = 100 %89 . 1 %85 . 5 % ;(2) 阻垢率法 abc = 100 %96 . 3 %95 . 0 % 。 由此可见 ,极限碳酸盐硬度法的分辨率要高于阻垢率法 。补充水中水稳剂 含量/ mg l - 1极限浓 缩倍率极限碳酸盐 硬度/ mmol l - 1水稳剂tr trtr2003004001 . 51 . 51 . 52 . 732 . 8

15、12 . 5610 . 811 . 110 . 1试验水 质 : 全 碱 度 3 . 95 mmol/ l , 全 硬 度 3 . 72 mmol/ l , 钙 硬 度2 . 52 mmol/ l ,氯离子 63 . 5 mg/ l ; 试验温度 45 1 ; 水稳剂浓度2 mg/ l 。表 2 阻垢率法试验结果结论3原水中钙离子/ mmol l - 1过滤水中钙离子/ mmol l - 1水稳剂阻垢率/ %极限碳酸盐硬度法对水稳剂的阻垢性能分辨率高 ,试验结果重现性好 ,并可实际指导现场操作 。此法适用 于火电厂循环冷却水处理水稳剂阻垢性能的评价 。tr trtr20030040010 .

16、010 . 010 . 09 . 19 . 28 . 5919285原水组分 : cacl2 10 mmol/ l , mgso4 3 mmol/ l , na hco3 10 mmol/ l ;水稳剂浓度 2 mg/ l ;试验温度 80 1 ;试验时间 6 h 。表 1 、表 2 结果表明 ,极限碳酸盐硬度法和阻垢率 法试验结果是一致的 。对于 tr200 和 tr300 2 参考文献 gb/ t16632 1996 ,水处理剂阻垢性能的测定 : 碳酸钙沉 积法 s .1种药剂 ,阻垢效果相近 。但用极限碳酸盐硬度法测得两者结果的差别为 2 . 93 % ,而用阻垢率法测得两者结 果的差别

17、为 1 . 09 % 。说明极限碳酸盐硬度法的分辨h g/ t2024 91 ,水处理药剂阻垢性能测定方法 : 鼓泡法s .23高秀山 ,杨东方 . 火电厂循环冷却水处理 m .出版社 ,2002 .中国电力64热力发电2004 (06)scaling and clogging. practice shows t hat t he developed scheme of anti scaling and clogging to be feasible.key words :medium and small scale indust rial boilers ; desulf uratio n

18、; scaling ; clogging ; anti scaling and cloggingsim ul atio n a nd em ul atio n system of service l ife p red ictio n fo r roto r of steam tur2bine wa ng qi , l ia ng zhihong , y ue jianhua et al( 35)abstract :at first , t wo main kinds of rotor damage for steam t urbines , i . e. creepage and fatig

19、ue damage , have been analysed , detail analysis and discussio n of calculatio n p rinciple and calculatio n met hod of t wo said kinds of damage being carried out . taking a 330 mw steam t urbine in o ne power plant in inner mo ngolia as st udied object , t he simulatio n and emulatio n calculatio

20、ns of service life for high p ressure rotor of t he said t urbine have been made by using t he researched and developed service life p redictio n emulating system.key words :steam t urbine ; rotor ; service life p rediclio n ; emulatio n systema n app roac h to the c hec king m ethod of small operat

21、ing ind ices fo r thermal powerunits wa ng l i l in , y e yongsong , wa ng jiajun ( 39)abstract :scientifically and reaso nably launching t he system of checking small operating indices in t hermal power plant s , t he ent husiam of operators for imp roving operating skill can be mobilized , and can

22、 benefit t he enhancing of eco no mic behavior for units operatio n. an app roach to t he p rinciple of checking small operat2 ing indices , t he calculating met hod of checked result s , and t he establishment of check database have been carried out , a realtime algorit hm for determining checked r

23、esult s based o n different operating co nditio ns and test values being reco mmended. the said met hod has been used o n many operating 300 mw unit s ,t he real time algorit hm not o nly can really reflect p ractical operatio n level of t he operator , but also can be helpf ul to discover p roblems

24、 existing in t he operatio n ,obtaining good result s in guiding p roductio n of t hermal power plant s , and in aspect s of enhancing eco no mic behavior and safe operatio n of unit s.key words :small operating indices ; check standard ; average value checking met hod ; real time algorit hmno ise c

25、o ntrol of d iesel generato r sets wa ng shu xin , mao shanyong , hua ng xinghua ( 42)abstract :alo ng wit h t he develop ment of boat s and ship s towards t he directio n of high speed and large capacit y , pollutio n p roblems of vibratio n and noise f ro m diesel generator set s are beco ming inc

26、reasingly serious wit h each passing day. taking diesel generator set o n a ship of medium capacit y as example , co mp rehen2 sive measures , such as isolating vibratio n , erecting noise reducer , and pasting bind damper and noise absorbing materials etc. , have been taken for co nt rollingnoise ,

27、 obtaining excellent effectiveness of noise co nt rol . the said measures are reaso nable , having low cost , p roviding reference value for co nt rolling noise of ot h2er power unit s.key words :diesel generator set ; noise co nt rol ; vibratio n ; noise pollutio nsway ing a nalysis of the servomot

28、o r fo r do ubl e extractio n steam turbine a nd co un2term eas ures of the co ntrol system y u tiebing ( 45)abstract :the causes leading to swaying of servo motor for double ext ractio n steam t urbine in anqing pet rochemical thermal power plant have been analysed f ro m so me main aspect s , such

29、 as set up of system parameters , delay rate of t he servo motor , and closed loop co nt rol of t he double ext ractio n steam t urbine etc. ,and countermeasures for eliminating t he t roubles being p ut forward. af ter implementatio n of t hese said measures , effectiveness is good , enhancing t he

30、 safety of steam t urbine operatio n.key words :double ext ractio n steam t urbine ; governing system ; elect ro hydraulic co nt rol ; servo motor ; delay rate ; decoupling co nt rola n air l ea ka ge co ntrol m ethod of air p reheaters based o n adaptive mod e ni yun f eng ( 48)abstract :directing

31、against t he p roblem existing currently in air leakage co nt rol system of air p reheaters for ho me made large scale t hermal power generatingunit s , a new met hod of air leakage co nt rol based o n adoptive mode has been p ut forward by using co mp uter database technology. result s of p ractice

32、 show t hatt he said met hod can effectively enhance t he co nt rolability of system , decreasing air leakage rate of t he air p reheater , p roviding guarant y for safe and f ull load op2eratio n of t he unit s.key words :t hermal power unit ; air p reheater ; clearance ; air leakage co nt rol ; ad

33、aptive modebrief d escriptio n of the negative p ress ure co ntrol system fo r bo il ers in seco ndp hase p roj ect of hua neng fuzho u power pl a nt c hen jian f eng , wa ng zhenhao ( 51)abstract :the design feat ures of negative p ressure co nt rol system in siemens made t xp dist ributed co nt ro

34、l system used for 2 300 mw unit s imported f ro mu k in t he seco nd p hase p roject of huaneng fuzhou power plant have been briefly p resented , including : ( 1) inp ut deviatio n signal of t he regulator and feedforward signal of forced draf t air flow ; ( 2) t reat ment of inp ut signal fluct uat

35、io n for t he regulator ; ( 3) adjust ment of gain for single and double unit s ; ( 4) bal2anced circuit ; ( 5) explosive p rotectio n in t he f urnace ; ( 6) high and low speed changing for induced draf t fan. the said co nt rol system has been p ut into opera2tio n and reliable performace under op

36、erating co nditio ns , such as start up and shut down of t he boiler , main f uel t rip , run back act uatio n , high and low speed switching etc. .key words :boller ; p ressure co nt rol system in f urnace ; negative p ressure co nt rol ; huaneng fuzhou power plantd evelopm ent of spa re space fo r

37、 d istributed co ntrol system a nd its appl icatio n in en2gineering ya ng hua , hu ba i yong , c hen heng zhong ( 54)abstract :through st udy o n spare space and load dist ributio n of dist ributed co nt rol system (dcs) for unit no1 of j iaxin power generatio n co mpany limited , t he expansible s

38、pace of t he said co nt rol system has been co nfirmed. hence , a technical ret rofit has been carried out , having revised t he t ransmit ting mode and t he cy2 cle time of original switching and analog signals , averaging t he load of various sub system for dcs , co nverting partial o n site pl c

39、co nt rol into dcs co nt rol ,enhancing t he auto matic level and operatio n reliabilit y of t he unit .key words :t hermal power unit ; dcs ; spare space ; switching quantit y ; analog quantit yclosed loop co ntrol system of cfb bo il ers c hen xiu ping , hua ng wei gang ( 57)abstract :the sit uati

40、o n and p roblems existing in co nt rol circuit s of analog variable co nt rol system for circulating fluidized bed ( cfb) boilers in daliuta thermalpower plant have been analysed , emp hatically describing t he st ruct ure of co nt rol circuit s for t he feed water and t he main steam temperat ure

41、, as well as t he sit u2atio n of t heir imp rovement . through debugging , t he co nt rol circuit of main steam temperat ure can be p ut into auto matic operatio n under operatio n co nditio n of main steam flow quantit y to be greater t han 50 % , and opening degree of t he desuperheating water va

42、lve to be greater t han 60 %. during t he time of co mpara2 tively stable boiler load , t he main steam temperat ure can be maintained in t he range 5 of t he set value.key words :cfb boiler ; feed water ; main steam temperat ure ; wdp e ; co nt rol system ; closed loop circuitretrofitting of water

43、l evel co ntrol system fo r high p ress ure heater of 350mw u2nits hu min , s hen qi ( 60)abstract :the defect s existing in t he co nt rol and p rotectio n sytem of high p ressure ( hp) heater for 350 mw untis iin huaneng nanto ng power plant have beenanalysed , and co ncrete ret rofit ting scheme

44、being p ut forward as follows : ( 1) eliminating p neumatic co nt roller , to realize co nt rol by using dist ributed co nt rol sys2 tem (dcs) ; ( 2) imp roving emergency drain mode of t he hp heater ; ( 3) increasing t he number of t ransducers ; ( 4) imp roving t he p rotectio n logic and set ting

45、 of p rotectio n parameters. af ter ret rofit ting , t he operatio n sit uatio n of t he said co nt rol system is good.key words :350 mw unit ; hp heater ; co nt rol system ; water level co nt rol ; huaneng nanto ng power planteval uatio n m ethod fo r scal ing reta rdatio n behavio r of water qual

46、ity stabil izinga gent used in circul ating water treatm ent at thermal power pl a nt j ia ng qi , ya n kun , xu jianxue ( 62)abstract :an evaluatio n met hod for scaling retardatio n behavior of water qualit y stabilizing agent by using ultimate carbo nate hardness met hod has been p re2sented , in

47、cluding measurment of scaling retardatio n behavier , as well as diterminatio n of evaluatio n indices , water temperat ure in test , co ncent ratio n of waterqualit y stabilizing agent , and circulating water flow rate of t he test facility etc. , and a co mpariso n wit h t he scaling retardatio n

48、rate met hod being carried out .result s of test show t hat t he ultimate carbo nate hardness met hod has many advantages , namely having high distinguish abilit y , good data rep roducibilit y , clear and definite guiding significance , as well as simplicit y and applicabilit y etc. , being suitabl

49、e for evaluating t he scaling retardatio n behavior of water qualit y sta2bilizing agent used in circulating water t reament at t hermal power plant skey words :termal power plant ; circulating cooling water ; water t reat ment ; water qualit y stabilizing agent ; eraluatio n of scaling retardatio n

50、 beharior ; ultimate carbo nate hardness met hodstudy o n watersaving, as well as a ntiscal e a nd a ntico rrosio n of circul atingwater in l a nzho u thermal power pl a nt no. 2 zha ng l ihua , zha ng zhengda ( 65)abstract :in view of t he qualit y of supplementary water for t he circulating water

51、in lanzhou thermal power plant no . 2 , a field test has been carried out by us2ing l y 8088 t ype scale retarding and corrosio n inhibiting agent , and optimal operatio n co nditio n being selected. af ter p ractical applicatio n , t he enrichmentfactor of circulating water has been enhanced f ro m

52、 original value about 2 . 0 to t he p resent value of 2 . 83 . 0 , having remarkable effectiveness for water saving ,and t he quantit y of agent dosing being small , t he corrosio n inhibiting and scale p reventing aim can be achieved o nly by using a dose of 46 mg/ l .key words :thermal power plant

53、 ; circulating water ; water saving ; scale retarding and corrosio n inhibiting agent ; anti corrosio n ; anti scaleappl icatio n of resid ential sewa ge in heze power pl a nt xu zhen , l i xiu juan , ya ng baohong et al( 68)abstract : the residential sewage in heze power plant has been t reated by

54、using aerated biological filt ratio n basin air floatatio n sand filt ratio n technology ,making t he qualit y of sewage af ter t reat ment to reach t he requirement s of supplementary water for circulatory cooling system. the technological p rocess , t he fea2 t ures of main t reat ment facilities

55、, as well as t he key point for at tentio n in t he t heir debugging have been briefly described. practice shows t hat t he said sewage t reat ment system is stable in operatio n , having high efficiency , various indices reaching t he requirement s of design ; af ter recycling utilizatio n of t he sewage , ef2fectiveness of water saving is remarkable.key words :power plant ; water saving ; residential sewage ; aerated biological filt ra