煤泥_煤矸石混烧技术在循环流化床锅炉上的应用

1、收稿日期: 20021224煤泥、煤矸石混烧技术在循环流化床锅炉上的应用李 玉,东野广磊,李丛峰(新汶矿业集团公司,山东泰安 271233摘 要 简单介绍了山东新汶矿业集团公司在130t/h 循环流化床(CFB锅炉上进行的煤泥、煤矸石混烧试验,提出了掺烧煤泥的最佳方式及应采取的措施。几个月的运行表明,CFB 锅炉掺烧煤泥不但技术上可行,而且还具有明显的经济效益和环境效益。关键词 循环流化床(CFB锅炉;煤泥;煤矸石;混烧中图分类号TK229.6 文献标识码A 文章编号10023364(200309004902 山东新汶矿业集团公司华丰煤矿是一座具有百年开采历史的老矿,建有装机容量37MW 的煤

2、矸石热电厂一座,其中有3台35t/h 和1台130t/h C FB 锅炉。近几年来,为提高煤炭质量,洗煤厂的入洗量增大,导致煤泥、煤矸石产量上升。为有效利用煤炭资源,该公司在130t/h CFB 锅炉上进行了煤泥、煤矸石混烧试验,经过几个月的运行,证明在现用的CFB 锅炉掺烧煤泥,不但技术上可行,而且还具有明显的经济效益和环境效益。1 系统构成华丰煤矸石热电厂130t/h CFB 锅炉系济南锅炉厂生产的YG 130/3.82M 6型中温中压、单汽包、自然循环锅炉,其循环燃烧系统由燃烧室、炉膛、水冷旋风分离器、返料器组成。炉膛为膜式水冷壁结构,两级过热器,中间设一级喷水减温器,尾部设二级省煤器和

3、一、二次风预热器;点火方式为床下点火,由4台刮板给煤机炉前正压给煤;含灰烟气经旋风分离器分离,大部分物料经返料器返回炉膛循环再燃,随烟气排走的微细颗粒被电除尘器收集。原设计煤种为以煤矸石为主的低热值燃料(Q net,v =12146kJ/kg。2 混烧试验2.1 煤泥泵送系统煤泥泵送系统由刮板机、搅拌机、NBS20型浓料泵、煤泥输送管道等构成。浓料泵可由就地泵房和锅炉热控室DCS 控制。洗煤水浆经洗煤厂压滤机脱水后,经输送皮带、刮板机送入搅拌机进行搅拌,水分控制在30%35%,然后由浓料泵通过煤泥输送管道将煤泥输送至锅炉炉顶,从炉顶落入锅炉燃烧室燃烧。为使煤泥能从炉顶落入燃烧室,在锅炉顶部燃烧

4、室上方开孔,将煤泥输送管道伸入锅炉(由于此处为负压区,只采取简单地封堵措施即可。煤泥输送管道长约350m,爬高约40m 。2.2 混烧机理CFB 锅炉在正常运行时约有1m 左右的料层,床温一般保持在850e 950e 。床料基本是由煤矸石燃烧后形成的炉渣,密度较大,耐磨性较好,而煤泥自身灰分较低、密度较小。煤泥进入炉顶,形成块状落下,炉顶距布风板约有30m 的距离,考虑烟气行走带来的阻力,大约需要3s 的时间,这足以使煤泥燃烧。 技术交流热力发电#2003(9o 由于煤燃烧具有爆裂的性质,煤泥块又具有良好的破碎性,因此,块状煤泥在下落的过程中碎裂燃烧,待落到布风板时,已经变成小块,不足以糊到布

5、风板上。另由于密度的差异,小块煤泥将/漂浮0在沸腾层中燃烧,不会沉积在布风板上影响锅炉的流化质量,也不会导致局部流化效果变差而造成结焦。入炉煤泥、煤矸石工业分析见表1。表1煤泥、煤矸石工业分析为了保证锅炉的出力,在运行调节中除了常规操作外,还要特别注意以下事项:(1保证各刮板给煤机运转正常;(2各安全阀经试验,确认动作正常;(3风机、给水等各项联锁试验良好;(4煤泥水分控制在35%以下。试验共分为3步:(1在煤矸石中添加部分原煤,使煤矸石与原煤混合后发热量达12550kJ/kg,稳定锅炉各项参数;(2按2B3的比例掺入煤泥,降低刮板给煤机给入量,给入燃料的发热量保持在12550kJ/kg,稳定

6、锅炉各项参数;(3保持煤泥的给入量,逐渐降低原煤量,增加煤矸石量,使混合入炉燃料发热量为9 802kJ/kg,稳定锅炉各项参数。主要试验数据见表2。表2主要试验数据项目燃料热值/kJ#kg-1主蒸汽压力/MPa主汽温度/e炉膛负压/Pa烟气氧量/%床温/e排烟温度/e料层差压/kPa返料温度/e风室风压/kPa负荷/t#h-1煤矸石+原煤12550 3.63.7440445-55-7012.112.79309501401457.57.89409507.67.8130132煤矸石+煤泥12550 3.63.8440445-40-5511.211.89309501401457.67.8955970

7、7.57.7131134煤矸石+煤泥9802 3.63.7440445-30-5011.612.39309501411457.57.89509607.57.7130132在风量不变的情况下,风室压力越高表明料层越厚,运行中维持正常风量不变情况下,风室压力应尽量维持在上述范围内;同时,在运行中尽量保持料层厚度,以免造成煤泥沉积,保证锅炉稳定运行,这就要求锅炉运行人员勤放渣、少放渣。床温的调节应采取调节入炉煤矸石量的方法,不要利用煤泥给入量来调节。此外,应要求运行人员加强监视,增强责任心,一旦发生床温升高,应迅速减少煤泥的给入量,避免因调整不及时而造成炉床结焦,进而导致返料器结焦的事故。3效果(1

8、煤泥与相同发热量的原煤相比较,价格约低130元/t,除去煤泥泵送系统所耗电费、设备折旧费、维护等费用,每燃烧1t煤泥可节约燃料费用约100元,如全年消耗8万t煤泥,则可为电厂减少燃料支出约800万元,效益相当可观。(2C FB锅炉燃烧煤泥,避免了洗煤水外流造成的环境污染,同时也减轻了因煤泥堆放、储存、运输带来的煤尘污染,为华丰煤矿洗煤厂的正常运行创造了良好的生产条件,提高了煤矿的经济效益和环境效益。(3拟再增加1台25m3/h的煤泥泵,并将煤泥泵房移至厂区以内,减少煤泥输送管道长度约为120m,同时也减少了因管路过长、拐角过多造成的管道堵塞。(4煤泥、煤矸石混烧技术的成功应用,为新汶矿业集团公

9、司其它矸石热电厂、煤泥热电厂成功燃用煤泥奠定了良好的基础,目前已有4台130t/h CFB锅炉采用了该技术,另有6台35t/h、4台75t/h C FB锅炉正在改造,以增加煤泥系统。欢迎订阅欢迎投稿欢迎刊登广告技术交流 p u热力发电#2003(9pan si on of th e rotor,an d pr odu cin g ther mal stress.A fter the pad of bear ing p ed estal at th e said e nd be ing re paire d th rough scr api ng,th e abovmen tion ed p r

10、ob lem havin g bee n solved .ANA LYSIS OF SEVERAL KEY ISSUES ON REDUCING NO x EMISSION BY REBURNING TERTIARY AIR WITH FINELY -PUL -VER IZED COAL XU Zhang et al (42,Th e i nflu en cin g factors up on re bu rn ing fin elyp ul ve rize d coal and the featu res of re bu rn ing ter ti ary ai r have be en

11、an alyse d,an d a tech n ical sc heme for reb ur ni ng the ter tiary air be ing p u t forw ard on the b asis of said an alysis.The con cen trator of fi nely -p ul verize d coal has be en selec te d,an d th e d istr ibu tion of excess ai r coefficie nt for reb ur nin g the fin ely -p ul ve r -ized co

12、al be ing de termin ed,solvin g c omp aratively w ell some face d p roble ms to u se te rtiary air for reb ur nin g.Th e r esu lts obtain ed h ave prac tical gui di ng effect for reb ur ni ng tertiary air d esign.OPTIM UM C OMBUSTION CONTROL OF CFB BOILERS YA NG Yong et al (47,Mai n parameters o f o

13、pti mu m comb ustion con trol for cir cul ati ng flu idi zed b ed (FCBb oile rs h ave b een presen ted ,and optimu m combu tion c ontrol of 75t/h CF B b oilers in a pow er p lan t b ein g carri ed out.Practice show s that,u nd er p rese nt ope ration le vel of man y d omesti c C FB boi lers,th rough

14、 optimu m comb ustion con trol,the stabil ity of b oiler op eration can ob viously be imp roved i n a comp arativel y lar ge r ange,solvin g or r elaxin g trou b lesome p rob lems,su ch as low b oiler th ermal effici enc y,sh ort oper ati ng p eriod ,b ad oper ating stabil -ity,high spe cific ele ct

15、ric en ergy con sup tion of au xiliary eq ui pmen ts,an d se rious boil er ab rasion etc.,havin g re mar kab le e conomic be ne fits.APPLICATION OF M UD -COAL AND GANGUE M IX ED BURNING TECHNOLOGY ON A C FB BOILER LI Yu et al (49,Test of mu d -c oal an d gangu e mixed b u rni ng on a 130t/h circu la

16、tin g flui diz ed b ed (CF Bboile r o f X inw en Mini ng In d ustry G roup C ompan y,S han don g Pr ovinc e,has bee n br iefly p resen ted,an d the op timal mode of ad mixin g mud -coal as w ell as measure s must be tak en b ein g pu t for ward .The op eration in several mon thes sh ows that the mu

17、d -coal ad mi xe d b u rni ng is not onl y tech n ically feasi ble ,bu t also h as econ omi c an d en viron me ntal be nefi ts.CA USE A NALYSIS OF ROLLER -C ASING BREAKAGE FOR MV M 25R TYPE COAL PULVERIZER Y ANG Ning et al (51,S even rol ler -casin gs o f MV M 25R type coal pu lveri zers all ocated

18、to b oiler s of tw o u n its in Zhu hai Pow er Plan t h ave bee n br oken early or later be fore re achi ng the d esigne d se rvice -l ife of 12000h .The macrostru ctu re analysis an d th e me tal lograph ic examin ation of brok en su rface show ,the main cause of th e roll er -casi ng b reakage is

19、the b ad q ual ity of manu -fac ture.In ord er to p reven t th e r ol ler -casin g from b reak age,the tec hn ology of manu factur ing roll er -casings h as b een i mproved ,an d the h ydrc ul ic oil pre ssur e ap p lied on roller s b ein g r eadju ste d.IM PROVEMENT OF EXPANSION SYSTEM FOR 200MW UN

20、 IT BY USING SELF -LUBRACATING SLIPPERS ZHANG Yong -jun et al (54,D irec ting against th e un smooth ly exp and in g p rob lem of the sl idi ng pi n system in c entral b earin g b ox of a 200MW un it at Hu angshi Pow er G ene ration CO Ltd ,Hub ei Provi nce,the cau ses lead in g to u n smooth cloggi

21、n g of th e sl idi ng pin an d d eformation of th e table -p late,as well as th eir in flu enc e u p on ove rtempe rature of the b earin g shoes have bee n examine d an d anal ysed ,and th e reliab il ity of sli din g p in syste m be ing en han ced b y u si ng sel f -lu b ricati ng grap h ite sli pp

22、 ers.OPTIM AL CONDITIONS OF DUAL -PUM P OPERATION FOR CIRCULATING -WATER PU MPS SHENG Huan -cheng et al (57,Th e in fuen ci ng factors an d op timal con diti ons for c han ging sin gle -pu mp op eration to d ual -pu mp ope ration con cer nin g mixed -flow type c ircu latin g -w ater p ump s of a 300

23、MW un it h ave b een discu ssed ,so as to en han ce the econ omi c aspec ts in ope ration of c ircu latin g -w ater pu mps.ARTIFICIAL LABORATORY BASED ON INTERNET FOR REMOTE V IRTUAL THERMOTECHNIC CONTROL Y ANG Yi -rong et al (60,In ord er to save large amou n t of ti me an d effort con su med for r

24、ep eatedl y grop ing and te stin g b efore pu ttin g th e c ontrol system i nto op eration ,as we ll as ove rcome th e limitation of spac e an d time i n the fiel d,an d artific ial laboratory based on In tern et for re mote virtu al the rmote chn ic con trol has been design ed .The struc ture an d

25、fu nction s of the h ard ware,the re alization of system commun ication ,as we ll as the str uctu re of th e arti ficial so ftw are ar e d escrib ed in detail .STUD Y ON MONITORING LOC AL CORROSION OF COND ENSER .S BRASS TUBES IN THERM AL POWER PLANTS SONG Jing -xia et al (63,Th e ju dge me nt of br

26、 ass tu be s .local corr osion b y u si ng join tly tw o e lectroch emical test me thod s,n amely the p ote ntial mon itorin g an d th e lin ear polari zation,has b een stu di ed u nd er l aboratory cond ition s.The re su lts show ,w he n p itting corr osion oc cur red on the b rass su rface,the p o

27、larizati on resistance of elec trode w as obvi ously dec rease d,an d th e corrosion p o -tenti al b ein g also ob viously lowe red.Th is ru le can b e u sed to moni torin g the d egree of p ittin g corr osion on th e matall ic su rface.IM PROVEMENT OF AUTOMATIC INTERFAC E TENSIOMETER AND APPROACH T

28、O TEST M ETHOD THEREOF LI Ye -feng et al (65,In view of the de ficie ncy existing in test meth od of origi nal automatic in terface tensiometer,some i mp rovemen t measu res have be en suggested as follow s:(1ad optin g magn etic pot seale d sen sor ;(2u si ng equ al -space mu ltip le p oints .cali

29、brati on;(3add in g comp en sation fun ction to th e ambie nt tempe rature ;(4maki ng the an alysis meth od to be p ro -gr ammed b y mean s of sin gl e ch ip p rocessor .A fte r improvemen t,th e measu rin g accu racy of th e sai d ten siome te r has bee n greatly e nh ance d,solvin g the p rob lem

30、of te st method sti pu -lated in p resen t N ational S tan d ar d havin g b een r estr icted b y th e amb ien t temp eratur e.DESIGN AND CALC ULATION OF OIL -PURIF YING SYSTEM F U Zhong -qing et al (67,Tak ing syn ch ronou s ope ratiion of b oth oil -ap p lyin g e qu ip me nt an d oil -p ur ifying e

31、 qu ip me nt as examp le,th e p rin cip le an d method of design and c alcu lation for oil -pu rifyin g equ ip -me nt have bee n descri bed ,an d p ractic al examp le of calc ulati ion b ein g gi ven.It is obtain ed from th eori ti cal analysis that the me thod s w hic h can be u se d to en su re th

32、 e qu ality of oil are as foll ows:(1i ncre asin g th e vol ume of oil tank ;(2decr easi ng the impu riti es mixed -i n oil;(3se lectin g an d usin g h igh ly e ffec tive oi l -pu ri fyi ng e qu ip me nt;(4se lectin g an d u sing oil -p uri fying equ ip men t w ith large flow qu an tity.APPLICATION OF HV VARIABLE FREQUENCY SPEED CONTROL TECHNOLOGY FOR ENERGY -SAVING IN FORC ED D RAFT FANS OF 670t/h BOILERS TIAN Jian -xu et al (70,Th e b asi c p rin cip les of variab le freq u enc y spee d con trol and th e advan tage s of u sing va