Nha May Nhiet Dien

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1. CC NGUN NNG LNG V CC VN CHUNG 1.1 Khai thc v tiu th nng lng Nng lng rt quan trng cho cuc sng, n l ch s quan trng v mc pht trin ca nn kinh t. Kim tra tiu th nng lng ca c nhn mnh hng ngy s hiu c th hn v tc dng, ngun gc, v loi/dng, v qui m, v hiu qu. n v o nng lng: J (Joule) n v thng dng khc: kW.h kgOE, TOE kgCE, TCE Nng mt vt khi lng 1 kg trn mt t ln 1m cn mgH = 1m*9.8m/s2*1m = 9.8 J un si 1 lt nc tiu th ht: 1kg*(100oC-30oC)*4,186 kJ/(kg.oC) = 293 kJ Nu 1 ba n ht: ?kJ Ngi hc 1h di bng tup in ht: 40W*1h = 40W.h = 40J/s*3600s = 144 kJ Lp hc ta trong 3 tit tiu th ht ? kJ Chy xe my 100km ht ? kJ SX 1 tn ximng, tu cng ngh, cn 3,7 n 10 GJ1 oil barrel (thng du) = 159 lt (khng qui ra J), dng ni n qui m khai thc du theo lu lng

Cc dng nng lng thng mi bao gm du m, gas, than , ci g, in vv. in, xng, du DO l nng lng cao cp. Cc ngun nng lng khc dng bin i thnh nng lng cao cp l nng lng s cp. Nng lng c vai tr ch o trong pht trin kinh t, n l h tng quan trng cho tt c cc ngnh sn xut v dch v. V vy nng lng phi c pht trin trc cc ngnh khc mt thi gian. Khng th xy cc loi nh my trong khu CN xong ri mi tnh xy mng cung cp in v xy cc cy xng trn ng i ti . Tiu th nng lng ca c th gii tng trng khng ngng (ch tr 2009) v tc hin ngy cng cao, khong 2% cho cc nm cui TK 20 ln 5% cho nm 2010. Th gii hin tiu th khong 12 t TOE, tc l khong gn 2 toe/ngi/nm, mt con s rt ln nn th gii ang nng dn ln cng chng c g l l. Tiu th trung bnh l vy nhng ta nn nh rng cc nc pht trin c mc tiu th nng lng theo u ngi cao gp hng ngn ln cc nc km pht trin. Nng lng tiu th ngay trong gia nh nc cng nghip c th bng mt xng nh nc ang pht trin, cn nhng vng cng thn cc nc ngho th ch cn t ci un v cht du ha thp sng cho ba n ti. Hot ng tit kim nng lng c cc nc cng nghip rt coi trng t nhiu thp k trc, nay th mang tnh cp thit ton cu. S dng nng lng hiu qu s gip ct gim tiu hao nng lng v cc ngun lc, gim pht thi. Cc nc ang pht trin, trong c Vit Nam, cn xem tit kim nng lng va l c hi va l tiu ch tt nm bt cc cng ngh v phng php t chc qun tr tin tin.

Source: BP Statistical Review of World Energy.

Hnh 1.1 Tng trng tiu th nng lng thng mi ca c th gii

Phn b nng lng tiu th theo ngun qua s bnh sau gip ta thy r hn ng gp ca tng ngun nng lng

Hnh 1.2. Cc ngun cung cp nng lng s cp

Hnh 1.2 cho ta thy du m vn l ngun nng lng chnh. Ngun ny d bo s t cc i trong thp k ny v cn kit dn ti gia th k, nh hnh sau:

URR (Ultimately Recoverable Resources)

Hnh 1.3. San lng dau mo th gii: lch s & d bo Vit Nam c tc tng trng tiu th nng lng khong 11%/nm, cao hn trung bnh th gii v ta ang thuc nhm kinh t km pht trin. Nn nh rng cng lc th tc tng trng GDP ca ta ch khong 7%/nm. Tnh hnh chung v sn xut v tiu th phn b theo cc ngun nng lng cng nh so snh vi mt s nc khc ca cc nm gn y nh sau: Du m 200 Tr lng ro (ke ca kh), triu TOE Khai thac dau, kh, triu TOE/nam 20 Ty le tr lng/ khai thac 10 Nam bat au khai thac 1986 Than a Tr lng ro, triu TCE Khai thac , triu TCE/nam Ty le tr lng/ khai thac 3500 25 140

Year Energy consumption per capita (kg of oil equivalent per capita)

1980 89

1985 102

1990 97

1995 135

2000 231

2005 360

Hnh 1.4. Tnh hnh tiu th nng lng ca Vit Nam

Tiu th nng lng ni chung v in nng ni ring bnh qun theo u ngi ca VN ang mc rt thp, phn nh nn kinh t ca ta. Nng lng in tnh trung bnh cho u ngi khong 1000 kW.h/(ngi.nm). Tng tiu th nng lng bnh qun u ngi ca VN khong 400 kgOE/(ngi.nm). hnh dung mc pht trin trong tng quan vi cc nc nm 2009, xem bng sau: USA Japan China Thailand Vietnam Tiu th kW.h/(ngi.nm) 14.340 8.530 2.570 2.260 880 Tiu th in nng mt s nc trong nm 2009 Nc

Cc n/m nhit in ln ca VN: Ph M 2500 MW, sx 22% in ca c nc Ph Li 4x110 + 600 MW, sx 6 t kW.h/nm khong 8,5% in ca c nc; Ninh Bnh sx khong 680 triu kW.h/n Ung B 300 MW (2007) + 300 MW, xs 2,7t kW.h/n C Mau 1500 MW, sx 9 t kW.h/n Mn 1: 2x330=660 MW 3,6 t kW.h/n Nhn Trch 2: 720 MW 1.2 Cac ac tnh cua ien thng pham in nng l dng nng lng cao cp. N c th d dng bin i qua bt c dng nng lng no khc vi hiu sut rt cao. Tuy vy c in nng ta phi tiu tn rt nhiu nng lng s cp, thng thng ti 3 ln nhiu hn in nng tiu th! Khong 70% nng lng s cp b tht thot vo mi trng theo gii hn ca nh lut nhit ng 2. Chng no chng ta cha nng gii hn nhit chu lc ca vt liu ln cao hn ng k so vi mc hin hnh ~550oC th cha th ci thin hiu sut c. Do vy sn xut v tiu th in lun cn s ch ca c x hi nng cao hiu qu. Vn hiu qu s dng in nng phi lun c t ln hng u. Sn xut in nng phi gn ngay vi tiu th, khng tch tr ng k c, ngun in ni vi ph ti qua dy in v nng lng truyn i nhanh nh in. iu ny t ra yu cu l cng sut pht phi lun lun ln hn cng sut s dng. Nu cha s dng n ni th cng sut pht phi ch. Khi nim v cng sut t: cng sut lp t hon thin, c kh nng huy ng pht in p ng nhu cu tiu th (ph ti). Biu ( th) ph ti: l hm ca ph ti in (kW) ph thuc theo thi gian. Trc tung l cng sut pht/tiu th v trc honh l thi gian 0 n 24h. Ph ti ca mng in ti mt thi im bng tng cng sut cc h tiu th ang vn hnh ngay lc . N lun thay i theo thi gian v lc no cng c nhng ai bt cu dao (CB/cng tc) ca mnh ln hoc ct ra khi mng. Nhn chung th th ph ti l mt ng cong c dng chu k ngy 24h v hot ng ca con ngi l theo chu k ngy m. Cng sut in tiu th hng ngy c dng ging nhau, thng l ng cong c hai nh trong ngy: l tra v 1 chiu, do thi quen sn xut & sinh hot ca con ngi. c bit nh cao nht l chiu-chp ti, trong khong 16:00-20:00, lc nhiu x nghip vn sx v hu ht n ng vi in gia dng (n TV, qut, HKK, gii tr vv) u a vo s dng, ph ti mng t

gi tr cao nht v gi l gi cao im. EVN hin qui nh 2 vng cao im l t 9:30 n 11:30 v t 17:00 n 20:00 cho cc ngy t th 2 n th 7, ch nht khng c gi cao im. Khong 22:00 4:00 l vng ti thp nht (hu ht cc gia nh tt in i ng, ch cn t x nghip duy tr sx ca 3 mt s xng, mt s n ng ). Khong thi gian 4:00 n 18:00 gi l vng bnh thng. Nhng ngy ngh, l, biu ph ti c dng khc vi ngy thng.

Hnh 1.5 V d v biu ph ti in mt ngy Biu cng sut tch lu hng nm (ph ti in hng nm) l cng s gi c cng cng sut tiu th ca tng ngy trong nm, v cho c 8760 gi (365 ngy) trong nm. Trc ng th hin cng sut, trc ngang l thi gian. N cho hay trong c nm h thng vn hnh my gi cng sut max,

my gi cng sut no , v bao nhiu gi cng sut min. Din tch di ng cong ny l tng nng lng tiu th trong nm.En = Nd 0

n

N MW Nmax

Nmin

En

8760 h Hnh 1.6 V d v biu ph ti in mt nm Ch s tmax = En/Nmax cho hay gi nh ta ch pht n nh vi cng sut max th sau bao nhiu gi ta sn xut nng lng in cho c nm nh bnh thng. N c gi l ch s gi s dng cng sut cc i. C ngha l: gi nh c th tch tr in thoi mi c th ngi ta chy my pht tmax gi cng sut n nh Nmax, xong ton b nhn vin in lc c th i ngh n ht nm! Ch s khc gi l h s s dng cng sut cc i o bng u max = En/(Nmax.8760), n cng phn nh bn cht ging nh ch s tmax trn. Cht lng in i ngi s dng th hin qua cc thng s in p, tn s v tin cy. Tn s cn c n nh cht ch 50 Hz +/- 0,5Hz. in p th thay i c trong khong rng hn, c th l 220V +5% -10%. tin cy l s m bo kh nng cung cp in lin tc (hay nguy c b ct in), bt c h thng k thut no cng n cha ri ro. 1.3 Mng in v Gi thnh in nng Cc nh my nhit in ni song song vi nhau to thnh mng in hay h thng in. Cc thnh phn chnh ca mng in gm cc NM in, trm bin p, ng truyn (dy) cao th, trm v ng phn phi h th. Cng sut t ca h thng bng tng cng sut t trong cc nh my ca mng cng li, cng sut ny phi cao hn nh ph ti cao nht ca mng. Nu cng sut ph

ti nh vt cng sut pht cc i ca h thng th s xy ra kh nng r mng do cc thit b t ng bo v tng nh my in s ct mnh ra khi mng khi b qu ti. C ngha l cc nh my in cn li phi ti nng hn, c th m ln lt ct ra (tan r) trong thi gian rt ngn. ngn nga tnh trng ny c quan iu phi c k hoch bo ng mc ph ti nguy him v ch ng ct gim ti, trc ht l ct cc mng c vai tr kinh t - x hi thp. t gi thnh thp l mt trong cc nhim v thng xuyn ca h thng nng lng. Gi thnh sn phm ca in nng o bng VND/(kW.h). Cc thnh phn chnh ca gi thnh gm: Gi thnh = khu hao (hon vn) + nhin liu + chi ph vn hnh & bo tr + ch ph khc Phn khu hao trong gi thnh c th rt ng k. Cng sut t ca h thng cc nh my in phi cao hn nh ph ti cao nht ca mng. iu ny ko theo yu cu u t c bn rt ln (xy thm cc NM in) lm tng gi thnh in nng do tng phn khu hao ( tr li tin u t). Nu cng sut ln ny ch c khai thc mt phn (chy mt vi gi trong ngy) cho phn ln s ngy trong nm th hiu qu u t s thp, tc l gi thnh cng cao. V vy cn c cc bin php gim tiu th in vo gi cao im, tc l gim chiu cao ca cc nh (ca th ph ti) xung. Tng gi in trong cc gi cao im l mt bin php gim ti nh. Tuy nhin s tt hn nu ta tng ng thi c thc ca x hi tng hiu qu s dng. in lc Vit Nam (EVN) hin p dng chnh sch 3 gi in (479; 871 v 1706 /kW.h) cho cc x nghip cng nghip c bin p ring, nhm khuyn khch gim ti gi cao im v chuyn hot ng sn xut t gi cao im sang gi thp im. Nh vy s gim c bin dao ng ph ti, to iu kin gim u t vo cng sut t m vn bo m c n nh h thng. in tht s l mt loi hng ho c bit, c ngha quan trng cho pht trin kinh t quc dn, an ton x hi v an ninh quc phng. Tt c cc chnh ph u can thip iu tit sx v tiu th in, khng ph mc hon ton cho c ch th trng iu phi. Cc chnh ph u yu cu ngi dn tit kim in, dnh in cho nhng lnh vc khng th thay th c. 1.4 Cc phng php nng cao hiu qu s dng nng lng: Li ch ca tit kim nng lng Chi ph nng lng trong SX: mt s ngnh ngh ch ph nng lng (nhin liu) chim phn ln gi thnh sn phm, nh NM in, xi mng, gch ngi (VLXD ni chung), giy, thu tinh, st thp Chi ph nng lng trn 1 ng ($, hay 1 v.) sn phm gi l t trng nng lng trong gi thnh. Nhu cu bc thit v gim t trng nng lng trong gi thnh sn phm ca cc x nghip; ca c nn kinh t c nn kinh t ni chung. C th th mi c sc cnh tranh trong qu trnh hi nhp. TKNL l gp phn bo v mi trng v gim c tiu hao cc ngun lc v gim x thi Mi kg nhin liu tiu hao s sn ra cc loi kh hiu ng nh knh v hiu ng ph hu ozone. Tnh th cho 1 kg C thun tu xem t ht s to ra bao nhiu kg CO2?. Th gii c cc quy nh v trn kh x, cc ch tiu ct gim. VN cng phi tham gia cc hip nh quc t. Tit kim in gip gim chi ph u t cho mng in Cc bin php tit kim nng lng gm cc nhm chnh nh sau: Cc bin php k thut: kim ton nng lng; cch nhit; thay i qui trnh vn