Inter-Ing INTERDISCIPLINARITY IN ENGINEERING SCIENTIFIC INTERNATIONAL CONFERENCE, TG. MUREŞ ROMÂNIA, November 2007.

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1 Intr-Ing 2007 INERDISCIPLINARIY IN ENGINEERING SCIENIFIC INERNAIONAL CONFERENCE, G. MUREŞ ROMÂNIA, Nvmbr EXERGEIC ANALYSIS HE OPIMIZAION WAY OF HE POWER SEAM GENERAORS OPERAING WIH COAL PULVERIZAION VASIU IOAN UNIVERSIAEA DIN ORADEA Kywrds:: pwdrd cal cmbustn, hgh xrgtc ffcncy, lw cnsumd ful. Abstract: h wrk prsnts sm cnclusns f th authr's rsarch carrd ut wth th am f ncrasng th nrgtc ffcncy f th stam gnratrs wth natural crculatn, runnng n cal n pulvrzd stat n th thrmal pwr plants. h xrgtc analyss f th thrmdynamc prcsss, whch tak plac n ths thrmal nstallatns, mad pssbl th dntfcatn f an ptmal pratng rang, charactrsd by an ncrasd vrall ffcncy and lwr ful cnsumptn. An ptmal rang f th ar-pwdrd cal mxtur tmpratur, flu gas utlt tmpratur and cnsumd ful flw was stablshd, whl maxmum valus f xrgtc ffcncy ar rgstrd. 1. INRODUCION h fssl fuls ar nw n a dmnant pstn n th structur f th prmary nrgy rsurcs usd n rdr t prduc hat and lctrc nrgy n th thrmal pwr plants. An mprtant part f th nrgtc prcsss n th thrmal cycl f th pwr plants ar achvd nsd th qupmnts f th stam gnratrs, whn thr ccurs a cnvrsn f th chmcal nrgy f th fuls n thrmal nrgy cntand n th lv stam prducd by th nstallatn. At prsnt, th nrgtc stam gnratrs wrkng wth cal pulvrzatn hav a lw vrall ffcncy du t th mprtant thrmal lsss whch ar rgstrd n th actual stag f dvlpmnt f ths thrmal qupmnts, [2]. akng nt accunt th actual Rmanan nrgy cndtns, th stam gnratrs wth pulvrzd cal burnng, wll b utlzd n thrmal pwr plants n th futur. hrfr, th ncras f th vrall prfrmancs f ths pwr stam gnratrs durng pratn bcam a rqurmnt n rdr t dmnsh th ful cnsumptn, t rduc th lctrcty and hat cst, t prtct d prmary surcs f nrgy f th cuntry. h qualtatv analyss f th thrmdynamc prcsss dvlpd n th nrgtc stam blrs wth natural crculatn runnng n pulvrzd cal, thrugh an xrgtc ffcncy, mad t pssbl t dntfy th ptmal rangs f th sm pratng paramtrs nsd whch th glbal ffcncy rachs maxmum valus, [2]. h xrgy rprsnts th maxmum usabl fractn f an nrgy frm, whch culd b btand by a rvrsbl transfrmatn n anthr nrgy frm, takng nt cnsdratn th stat f th ambnt. I-41-1

2 2. EXPERIMENAL RESEARCH h xprmntal rsarch has bn achvd n th nstallatn f a stam gnratr wth natural crculatn dlvrng 400 tn/hur (111.1 kg/s). h furnac s fully scrnd wth mmbran walls cnsstng f tubs f lw damtrs havng 60x5 mm. Raw cal supply Ht flu gas Pwr stam M1 gnratr Ar Prdryng Pwdrd cal- prhatr Flu gas twr ar mxtur utlt M2 M4 Mll M5 Slag dscharg M3 Prhatd cmbustn ar Atmsphrc ar ntak Fg. 1 h cal prparatn and cmbustn systm f th pwr stam gnratr h man tchncal charactrstcs f th xprmntal stam gnratr at nmnal lad ar: stam flw Dn = kg / s ; thrmal capacty Ptn = 340 MW t ; suprhatd stam tmpratur n = 823 K ; stam prssur pn =13. 7 MPa ; fd watr tmpratur = 503 K ; cmbustn ar tmpratur = 513 K ; flu gas tmpratur aftr hatr aa = 413 K, [2]. gv ac h prcsss f prparng and burnng cal pwdr achvd n th thrmal pwr plants ar ndcatd n fgur 1.h cal grndng qupmnt s cmpsd f 6 mlls havng 30 abl 1- Avrag charactrstcs f th quvalnt ful Chmcal lmntary analyss al ntal stat Symbl Unt Avrag valus Carbn Hydrgn Sulphur (cmbustbl) Ntrgn Oxygn tal humdty Ash Lw hatng valu at ntal stat Hgh hatng valu at cmbustn stat C % m, H % m, S cm, % N m, % O m, % W tm, % A m, % Q m, kj / kg Q mc sm, kj / kg tn/hur, f whch 4 5 mlls wr mantand n pratng stat n rdr t assur th thrmal lad f th stam gnratr, rqurd nsd th pwr plant at a crtan pnt. h pwdrd cal fnnss was n rang f R = %, n 0.09 accrdanc wth th fan mlls grndng lmnts war cycl. Cal pr-dryng s achvd usng ht flu gass, xtractd frm th fnal part f th furnac at a tmpratur f 950ºC. h ar fr th prcss f cmbustn was prhatd at ºC n a rgnratv qupmnt usng th rcvrd hat f th utlt flu gass. Fr th burnng f pwdrd cal a tchnlgy f prparatn wth cal dust I-41-2

3 cncntratr and drct blwng sktch n furnac f th flw mxtur f ar cal has bn usd, [2]. h valus f th szs fr th ful supply, th cmbustn ar, th flu gass, th slag and ash dscharg crcuts usd n th xrgtc analyss hav bn masurd n th fllwng pnts, ndcatd n fgur 1: M1-flw and charactrstcs f th cnsumd cal; M2- prmary ar-cal dust mxtur paramtrs; M3-prhatd ar cmbustn tmpratur; M4-flu gass utlt tmpratur; M5-ncmpltly burnt cntnt frm slag and ash. h chmcal and nrgtc prprts f th cal ar varabl n a wd rang durng th pratn f th stam gnratr. Fr ths rasn t was ncssary t dfn a ful havng mddl prprts. h avrag prprts f th quvalnt burnt ful, whch s a mxtur btwn cal and l, ar ndcatd n tabl 1, [2]. h man ful usd fr th stam gnratr runnng was lw-grad cal, charactrsd by hgh humdty and ash cntnt, havng a rducd hatng pwr. h flam supprt f th pwdrd cal burnr was assurd by usng l wth lw sulphur cntnt. 3. MAHEMAICAL EQUAIONS OF HE EXERGEIC ANALYSIS h xrgtc ffcncy f th stam gnratr η can b xprssd n th fllwng frm [1], [2] : Eu Π η = 100 = [%] (1) Et Et whr : E [kw] - usful xrgy utput flw prducd by stam gnratr, t u E [kw] - ttal xrgy nput flw f th analysd thrmal systm, Π [kw] - sum f th xrgy flws lst frm nstallatn. tal xrgy nput flw rsults frm th balancd quatn : E t = E + E + E + E = E + Π, [kw] (2) ch fc fa aa u n whch : E ch [kw] - chmcal xrgy nput flw f th quvalnt ful, E fc, E fa, E aa [kw] - physcal xrgy f th quvalnt ful, cmbustn ar and fd watr nput flws. h cmpnnts f th ttal xrgtc nput flw E t, ar dfnd as fllws, [2], [3]: E fc E ch = B, [kw] (3) n = Bc c pc t 1 c + B p c pp t p 1, [kw] c p (4) E fa = 1 B f Va ac λ, [kw] ac (5) Eaa = 1 Daa aa, [kw] aa (6) h usful xrgy utput flw E u s dfnd by quatn : I-41-3

4 [ ] + Eu Dab ab Daa aa B λ f Va 1 ac 1 ac h szs mntnd n th rlatns (3) (7) rprsnt: B, Bc, B p[ kg / s] -quvalnt ful flw, cal and ful l flw; [ kj / kg] -spcfc xrgy f th quvalnt ful; = ac ac n, [kw](7) c pc, c pp - mdum valu f spcfc hat at cnstant prssur f th cal and ful l; λ -ar rat n th furnac; f 3 Va[ mn / kg] -thrtcal ar vlum fr th quvalnt ful burnng; tc, t p[ C] - cal, ful l tmpratur; ac, ac[ kj / kg] -spcfc nthalp f cmbustn ar bfr and aftr prhatr; ac, ac[ K] - tmpratur f cmbustn ar bfr and aftr prhatr; Daa, Dab[ kg / s] -fd watr nput flw, dlvrd stam flw; aa[ K], aa[ kj / kg] -fd watr nput tmpratur and spcfc nthalp;, [ kg / s] -fd watr nput and dlvrd stam spcfc xrgy. aa ab 4. RESULS AND CONCLUSIONS h bhavur f th stam gnratr wrkng wth cal n pulvrsd stat was analysd n 6 pratng rgms charactrsd by dlvrd stam flw nsd th rang f 66.1 kg stam/s kg stam/s (238 tn stam/hur 391 tn stam/hur). Basd n xprmntal masurs, th calculatns achvd accrdng t th rlatns (1) (7) ndcatd n chaptr 3, hav prmttd t stablsh th ttal xrgy nput flw E t, th usful xrgy utput flw E u and, fnally, th valus f th xrgtc ffcncy η f th analysd stam gnratr. h graphc crrlatn stablshd by xprmntal rsarch, basd n xrgtc analyss, btwn th pratng paramtrs masurd n cal prparatn and flu gass crcuts, n th n hand, and th xrgtc utput, n th thr hand, taks nt vdnc ptmal rangs f th stam gnratr runnng n cal pulvrsatn, charactrsd by maxmum ffcncy and lwr ful cnsumptn. h admssn f ar-pwdrd cal mxtur n th burnng spac at ptmal tmpraturs, whch rsults frm th prpr ncras f th prhatd cmbustn ar tmpratur, ld t th mprvd gntn and burnng cndtns f cal partcls, du t th hghr lvl f th cmbustn tmpratur achvd nsd th furnac. h hgh ntnsty f th abstractd hat n th cmbustn spac was btand thrugh a gd carbn xdatn. At th sam tm, th prcss f hat transfr t th scrnd walls placd n th radatn zn bcms strngr du t th unfrm thrmal lad f th furnac. All ths thrmal prcsss hav a rmarkabl cntrbutn t th dcras f th man xrgy lsss whch lft th stam gnratr furnac, cnsst n th xrgy lst flws by rvrsblty f th burnng and hat transfr prcsss, as parts f th ttal xrgy lsss Π. h nflunc f th ar-pwdrd cal tmpratur, masurd at th utlt frm mlls sparatrs, abut th xrgtc ffcncy s shwn n th fgur 2. I-41-4

5 Exrgtc ffncy [%] ,2 152,3 156,4 157, , Prmary mxtur tmpratur at th burnrs nlt t c [ C] Fg. 2. h dpndnc btwn th prmary mxtur tnpratur and th xrgtc ffncy A rang f th prmary mxtur tmpratur at th burnrs nlt t c = C can b bsrvd, whl th xrgtc vral utput rachng th hghst valus, [2]. By ncrasng th hat flw dlvrd t th cmbustn ar n th prhatr, th tmpratur f th flu gas was rducd aftr ths thrmal qupmnt and, n ths way, an mprtant dmnshng f th xrgy lsss by th flu gas xhaustd frm th stam gnratr, was achvd. A zn f th flu gas tmpratur at th utlt f th stam gnratr, t gv = C was stablshd n a graphcal way, n whch th maxmum valu f th xrgtc utput can b rgstrd, (fgur 3), [2]. Exrgtc ffcncy [%] ,5 183,5 185 Fg.3. h nflunc f th flu gas utlt tmpratur abut th xrgtc ffncy f th stam gnratr Flu gass tmpratur t gv [ 0 C] I-41-5

6 h ncras f th ffcncy f th stam gnratrs, by pratng n an ptmal rang f th tchnlgcal paramtrs, had an mprtant ffct n th rducng f th cnsumd ful flw. h crrlatn btwn th quvalnt ful flw cnsumptn and th xrgtc utput f th stam gnratr s shwn n fgur 4. In a rang f th burnt ful, maxmum valus f th xrgtc ffcncy can b bsrvd. In th cas f th analysd stam gnratr, btwn B = kg cal/s, th hghst valus f th xrgtc utput η = 25.5 % ar btand, [2]. Exrgtc ffcncy [%] ,47 23,65 26,47 28,34 28,77 32, Equvalnt cnsumd ful flw B [kg/s] Fg. 4. Maxmum xrgy ffcncy f th stam gnratr dfnd by an ptmal ful cnsumptn hs xprmntal rsarch has a practcal mprtanc fr th spcalsts n th fld f thrmnrgtcs wrkng n th pwr plants quppd wth stam gnratrs wth natural crculatn burnng pulvrsd cal, n rdr t dfn th ful cnsumptn rqurd fr runnng wth hgh prfrmancs. BIBLIOGRAPHY [1]. Mădărăşan,., Bazl trmthnc, Edtura Sncrn, Cluj-Napca, [2]. Vasu, I., Prfrmanţl gnratarlr d abur nrgtc p cărbun pulvrzat, Edtura Unvrstăţ dn Orada, [3]. Bjan, A., hrmal dsgn and ptmzatn, Edtura Wly, Intrscnc, Nw- Yrk, I-41-6