NLN''''105 5/2012''''17 UNG DUNG CDNG NGHE CHUYEN DOI DONG CO XANG SANG SUDUNG KHi THIEN NHIEN NEN CNG "Appl icat ion C o m p r e s s e d Natural Gas (CNG) as an al ternat ive fuel for Gaso l ine Eng ine" T[.]
NLN'105-5/2012'17 UNG DUNG CDNG NGHE CHUYEN DOI DONG CO XANG SANG SUDUNG KHi THIEN NHIEN NEN CNG " A p p l i c a t i o n C o m p r e s s e d N a t u r a l G a s ( C N G ) as a n a l t e r n a t i v e f u e l f o r G a s o l i n e E n g i n e " TS N G U V e N S T T H A N G & Cong su- - Cong ty CP Kinh doanh Khi hoa long mifin Nam (PVN) De tai da tap trung xay dwng ca s& ly thuyet wng dung chuyen doi xe dgng ca xang sang si> dung Khi nen thien nhien (CNG - Compressed Natural Gas) Da chuyen doi SLP dung CNG cho 02 xe Toyota Innova va Toyota Corolla Altis va tien hanh cac thong so ky thuat va so sanh cac ket qua sCr dung CNG va xang Chi phi nhien ligu CNG da giam han 35% so vai sw dung xang De tai da trien khai dai tra a TP Ho Chl Minh va Tinh Ba Ria Vung Tau vai han 300 xe chuyen doi sang sw dung CNG Cong ty CP Kinh doanh Khi hoa long mien Nam, Tong Cong ty Khi Viet Nam, thuoc Tap doan Dau Viet Nam tien hanh Nhom tac gia cung de xuat mgt so chinh sach de nghj Chinh Phu va cac ca quan quan /y hd tra di trien khai khap toan quoc nhim giam thieu nhiim moi trwong I.GiaiTHIEU Trong mpt thdp ky tro' lpi ddy, fl nhifim khflng dd tro thdnh mpt van de mang tinh cdp bdeh doi v&\ ede dfl thi phdt trien Do viec tim kiem va s u dung nhifin lieu thay the cho xdng ddu edng dupe khuyin khieh Nhifin lifiu thay the phai dam bao cdc tieu ehi nhu giam thieu nhifim mfli truo'ng, an toan vd thudn tien s u dung vd gid thdnh s u dyng hap 1^ VPi nguon khf thien nhien on djnh tgi Vifit Nam vd dam bao ddp ung cdc tifiu chl trfin, vifie s u dyng Khi thien nhifin nen (CNG) Id mflt nhung lya chpn uu tifin hdng dau Sau ddy Id bang so sdnh tfnh c h i t hfla ly giua CNG vd cde lopi nhifin lifiu khde: (bdng 1) Nhung lpi fch md CNG mang Ipi s u dyng so vai mpt so nhifin lieu khde - Vfi mdt kinh te: Giam khd nhieu ehi phf nhien lieu (khoang 30%) s u dyng CNG cfl gid re han cdc loai nhifin lifiu truyen thong khde Id LPG, xdng, dau, Mdt khde, cdc phuang tifin, thiet bj s u dyng CNG efln giam dupe ehi phi bao tri bao du6ng dflng ca xe CNG Id nhien lifiu spch, giam thilu ede yeu to gdy hai cho dflng ca Ngodi ra, ve mdt vT mfl, ung dyng CNG Giao thong vdn tai eon giCip nhd nuPc giam thieu nhdp khau xang dau, d6ng thfl'i edn dam bao ve mat an ninh nang l u p n g cho q u i c gia (do Vipt Nam ehu dpng nguon d p thien nhifin) Bang So sanh tinh hoa ly giu'a CNG va cac nhien iigu khac Die tfnh CNG Khfing 0.64 (air=1) -162 50 1900 540 120 Mdu, mill Ty trpng Nhi^t ai> s6i (°C} Nhi$t trj (MJ/kg) Nhiet a(Sch^y(''C) Nhifit dO kich n6 ("C) Chi s i octan LPG Khong 51-0'56 (water = 1) - 43 - - 46 1983 476 97 - 112 Diesel Co 0.82 - 0.87 (water = 1) 175-370 42 1780 280 N/A XSng C6 72 + 0-87 (water = 1) 40 ->- 200 42.9 2030 264 83 + 95 Sau day la mo hinh cung d p CNG tpi Tp Hfl Chi Minh va Ba Rja - Vung Tau: (hinh 1) Hoiher - Daughter System MAIN GAS PIPELINE ->•• NGV TRAILER ] [TRAILERS DISTRIBUTION TRAILER GROUND STORAGE CASCADE^ ằ->ã P"^xđ->i COMPRESSOR COMPRESSORS MOTHER STATION DAUGHTER STATION Hinh Mo hinh Tram mg va Tram nen CNG ^ 18* NLN-105* 5/2012 - V§ m$t an todn: CNG la loai nhien lipu ca ban dam bao an toan han cdc loai nhien lieu long khde, cdc thilt bj c h l tao dupe kilm soat ngat ngheo v l mpt an toan phong ching chdy nfl Sau day la bang so sdnh nguy ca chay n l cua CNG so vo'i cde nhien lipu thflng thud'ng: (bang 2) - V l m|t moi truo'ng: Viec si> dung CNG thay thfi cho cdc loai nhifin lieu dang sii dung hipn se giam dupe khd lo'n cae chdt dpc hpi gay nhilm mfli truo'ng, gay hieu Crng nhd kinh Vo'i mpt so nghien cuu tren t h l gifl-i, lupng thai cua nhien lieu CNG so vo'i cdc nhien lieu khac (Xang, Ddu LPG) dup'c dua nhu bang ting hpp duo'i day: (bang 3) - Tilm ndng su dung CNG he thflng GTVT tai Viet Nam: Vi^t Nam cfl tru lupng thifin nhifin In dinh nen chij dpng vifie cdp va giam bot viec nhap khdu xdng, ddu, II K^T QUA TRI^N KHAI L A P DAT, CHAY THl>, DO DAC VA DANH GIA Dfi thu nghiem viee si> dung CNG lam nhien lipu cho cac Phuang tifin giao thong van tai, PV Gas South da tiln hanh thu nghiem cho 02 xe dpng ca xang (co c h l dO phun xang dipn tu) Id Toyota Innova 07 c h l va Toyota Corolla Altis 05 cho tai Phong thi nghiem Trpng dietri Dong ca dit thuoc Dpi hpc Quic gia Tp H i Chi Minh vo'i 02 nhifin lieu de so sdnh Id Xang A95 va CNG Cdc npi dung d l tiln hanh thu nghipm gim: - Do lyc keo (N) va Cong suit keo (kW) tay sfl 04 tai cac tic d | 30, 45, 60, 75 km/h; - Do nflng dp thai tpi cac t i c dp 15, 3Q, 45, 60, 75 Km/h vd c h l elm chung; - Do tho'i gian tang toe ngdn nhdt cua to tu din 80 km/h; - Do tieu hao nhifin lieu cua t6 van hanh theo ehu trinh Japan 10-15 Sau day Id kit qua dpt dup'c dli vfl-i tCrng loai xe: 11.1 Do lire keo (N) va cong suit keo (Kw) cua Innova va Corolla Altis nhu sau: (cac bang 4,5,6,7,8,9,10) Bang So sanh nguy ca chay no giwa CNG va cac nhien lieu khac Thong so Kha nang bSt li>a Nhiet boc chay Nang flO gio"! hgn ty boc cheiy V^t lieu chLPa Phy kien CNG Nhe hen khong khi, d§ tan vSo khong "650°C Xang DSu LPG Nang hon khong khi, tich tu dLfo-i d^t, ba li>a de dang ~250-275^"~ 48l''C 2% * 5% 5% -15% 6% •*• 6% Thep thyong, ap suat thiet ke 18 bar Vat lieu (Kc biet ^P suat nh tren 585 bar Emergency Shuts Off Valve se ti^r dpng ngi ddng de tranh mpi su' ro n khi ggp si,f co Th6p thu'ang khang t^ Bang So sanh ti lg thai giO'a CNG va cac nhien lieu khac NG/CNG LPG_ Diesel Xang Carbon Monoxide (CO) - 60% - 20% - 40% """"100% Nonmetal Hydrocarbon - 90% -10% -10% 100% Nitrogen Oxide (NO) -10% + 20'% + 700% 100% Bang Kef qua thu' nghiem Cong suat keo va Lyc keo xe Toyota innova Toe a? (Km/h) 30 45 60 75 Cong suat keo (kW) CNG Xang Lech 12.49 10.86 -1.63 21.14 19.03 •2.11 30.26 26.77 -3.49 37.95 33,39 -4.66 Trung binh Tyle% -13.1% -9.9% -11.5% -12.0% •11,6% Xang 1497.80 1691,17 1815,69 1821,54 Lyc keo {N) CNG L^ch 194,89 1302,91 1522,63 166,64 1606,23 209,46 218,64 1602,90 Trung binh Tyif% -13,0% •9.9% -11,5% -12,0% •11.6% Bang c (L/IOOkm) 12,14 Quang du'O'ng (km) 4,13 CNG TiSu hao NL (gram) 298,7 Djnh mi>c (kq/IOOkm) 7.21 CNG Tigu hao NL (gram) 298,7 Oinh mi>c (kq/IOOkm) 7,23 , Bang 12 Danh gia ve lai ich ich kinh te giwa nhien Hgu CNG va xang cua 02 xe Toyota Innova va xe Toyota Corroia Altis MiJc tieu hao nhien li^u Xe Nhien lifu Do'n gia Toyota Innova Xang 22,900 VND/Lit CNG 24,690 VND/kg 7,21 Kg/100km 178,015 VND Toyota Corolla Altis Xang 22.900 VNfi/LIt 12 14 Lit/100km 278,000 VND CNG 24,690 VND/kg 7.23 Kg/ 100km 178,510 VND " 11 86 Lit/100km 11.5 Danh gia + Doi vo'i v^n de dpng co va kha nang tang t6e: CNG la nhien lipu co nang lupng h6n hp'p thip hon so voi xang (3,1 kJ/kg so vo'i 3,46 kJ/kg) v^ hinh h6n hpp o ty lp khong khi/nhien lipu ly tu'O'ng ngheo (loang) han so vo'i xang (17,2:1 so v&\ 14,7:1) nen nang lupng tao sy chay hon hpp CNG-khong thap han so v&\ h6n hp'p xSng-khong Dieu tao ap suit chi thj trung binh xy-lanh dpng ca giam Vi v§y, cong suit va mo-men dpng ea su" dung CNG giam so vd'i SLP dung nhien lieu xSng Vi cong suat vh m5-men dpng ca su dung CNG giam dan den vipc kha nang tang t6c cung giam + Ddi vo'i vin 6i thai: Vipc su' dung CNG lam nhien lieu cho hieu qua ro ret v^ viec giam thilu thai m6i tru'O'ng nhu': CO giam 60% d6i vai dpng ca xe Toyota Innova va giam 100% d6i vai dpng ca xe Toyota Corolla Altis; CO2 giam 23,5% d6i vai xe Toyota Innova va % d6i vai xe Toyota Corolla Altis IVI^c dCi HC CO tang dot biln, nhung chung ta cQng de dang nh$n thiy ring HC xa chu yeu Id san pham nhe (CrC2) phin ehinh cua CNG la CH4 gin nhu khong gay dpc hai so Scinh vdi c^c hydrocabure n^ng xa dOng ca xSng hay Diesel Chi phi 271,590 VND Chenh If ch Ti4t kifm 93,579 VND 34,5 % 99.496 VND 35.8% Do d6, CNG dem lai hieu qua ro r^t vipc giam thilu nhiem moi trud'ng + D6i VO'I kha nang tiSu hao nhidn li§u: Doi vo'i ca 02 xe thi nghiem Id Toyota Corolla Altis vd Toyota Innova c6 cong suit vd dung tich lam viec dao dpng tu 1794 cc den 1999 cc deu co muc tieu thg nhien lipu trung binh la 7,22 kg/ 100km Trong do, mpt binh CNG dung tich 90 lit thSng thud'ng chua dugc 14,3 kg Do d6, v6i mue d6 tieu thu nhien lieu CNG nhu tr§n, ta co t h l dam bao edc phuang tien van chuyin vdn thuan tipn cho m5i ldn npp CNG + Danh gid v l lo'i ich kinh t l : Can cu tren cac so Ii0u dpc thyc t l , gid ban vd xang dup'c c6ng b l tai tho'i dilm hi0n tai (giua Cong ty co phan Kinh doanh Khi h6a long mien Nam (PV Gas South) va cdc hang taxi - gi^ nhien lieu CNG bdng 70% gia xdng), ta c6 bang so sanh Ipi thl kinh t l su dyng nhifin lipu Id CNG so vo'i Xang nhu sau: (bang 12) Ngodi ra, d l i vd'i nhi§n lipu CNG san phim se chay gin nhu hoan todn, khdng gdy ddng c|n ho$c bd hong ddng ca ciJa cdc phuang ti$n nen se keo ddi chu ky bao dud'ng vd tuii thp mdy moc thilt bj -> v l ting t h l vi^e sii dyng CNG Idm nhifin lipu cho hfi thing v^n tai ndi thdnh vSn dam NLN* 105-5/2012* 21 bao hipu qua, he thong dud'ng xd khdng yeu cau cdng suit, dpng ca cao; mat khde cdn gdp phin ldm giam thilu d nhilm mdi trudng mOt each rd r^t npi thanh; vd dilu dae biet quan trpng Id su dyng CNG lam nhifin lieu tilt kifim han 30% chi phi so vdi su dung nhifin lifiu la xdng Ve mat vT md, Crng dyng CNG Giao thdng vdn tai edn giup nhd nudc giam thilu nhap khiu xang diu, dong thdi cdn dam bao vfi mat an ninh ndng lupng cho qudc gia (do Vipt Nam chu ddng ngudn d p thifin nhifin) III.DANH GIA TiNH K H A THI: xe s6 lupng xe chuyin doi Id tuang doi ldn vd gilng nhau) IIM D5 xult phifcng an chuyen d l i SIP dyng CNG cho xe taxi tal khu vyc Tp Hd Chi Minh: Vdi so luang taxi tai Thanh phd H6 Chi Minh han 12,500 ehiic vd hau hit Id edc xe ddng ca phun xang difin tu nfin vipc ehuyfin ddi sii dyng CNG se dem lai rit nhifiu lai ich, dd cd 03 lpi ich cy thfi nhu Hpn chl dupe su phy thupe vao lupng xang dau nhap khiu; Giam thilu nhiem mdi trudng, vd tilt kipm chi phi nhien lipu - Thdi gian khiu hao thilt bj sdm (trong khoang 01 nam) Vdi muc tifiu su dung CNG dam bao tilt kipm il tdi thilu 30% chl phi nhifin lipu, chung tdi d l xult phuang dn ehuyfin doi nhu sau: Cdc hang taxi sfi ddu tu bd chuyin ddi sii dung CNG vd PV Gas South se tap trung d p khi, diu tu hp thing tram nap vd bdn CNG bing 70% gia xdng Ddnh gid tinh hifiu qua kinh t l cua Phuang an trfin: + Tii dd, Chung ta cd t h l thay dupe thdi gian thu hdi chi phi ddu tu bd chuyin d l i sii dyng CNG nhu sau: 64,000,000 VND/xe - 168,940 VND/ngdy = 378 ngdy + Nhu vpy, d l i vd'i Phuang an trfin vipc diu tu bp ehuyfin ddi su dung CNG Idm nhien lipu cho ddng ca hodn toan dam bao kha thi ve mdt kinh t l vd cdng tac quan ly nhu: - Cde hang taxi chu ddng cdng tdc kilm sodt thilt bi, bao tri, bao dud'ng bd chuyin ddi III.2 Thi dilm chuyen ddi mot sd ddu xe taxi va xe cua tap doan Petrovietnam: Mae du tii thang 09/2009 din thang 09/2010, Cdng ty c l phdn Kinh doanh Khi hda Idng miln Nam chJ ehuyen ddi cho 09 xe cua dan vj minh Tuy nhifin, tii thdng 10/2010 den thang 06/2011, PV Gas South da chuyin ddi edng thfim 295 xe Sli dung CNG, dd gom: + Taxi Quang Hung (tai Vung Tau): 37 xe + Taxi Gill (tai Vung Tau): 50 xe + Taxi o l u Khi (Tpi Vung Tdu vd Tp Hd Chi Minh): 75 xe + Xe cua Tap dodn Ddu Vipt Nam: 133 xe 11 + Trfin ca sd chi phi tilt kipm cho moi quang I! dudng di chuyin 100km cua xe Toyota Innova vd Cdc mau xe dup'c chuyen doi sii dyng CNG i! Toyota Corolla Altis lln lup-t Id 93,579 cung rit da dang, nhu Toyota (Camry, Corolla, VND/IOOkm va 99,496 VNO/IOOkm (chi tilt tai Fortuner, Innova, Vies Land Cnjlser); Ford Sang 12, Chung tdi d l xudt chi phi tilt kipm trung (Laser, Escape); Huyndai (Santa Fe, Grand, binh Id' Hiace); Mitsubishi Grandis, Mazda, Kia Carnival, Chevrolet Captiva (93,579 + 99,496)/2 = 96,537.5 VND/IOOkm •^ Theo khao sdt, hdng ngdy cae xe taxi di chuyen qudng dudng tii 150 km din 200 km Dfi xult quang dudng di chuyin trung binh la 175km/ngay Vific triln khai su dyng CNG Idm nhifin lifiu thay thl dupe tap trung tai khu vye Tp Hd Chi Minh vd Vung Tau, cac trpm d p tpj cdc dja dilm sau: + Tii chi phi tilt kifim trung binh va quang dudng di chuyin, ta cd thl tinh todn dupe chi phi nhifin lifiu tilt kipm duac mpt ngdy van hanh (khi Sli dyng nhifin lipu la CNG) la: + Tram d p CNG Phd Quang: S l 01 Pham Hong Thdi, Phudng 02, Qudn Tan Binh, Tp H i Chl Minh 96,537.5 VND/IOOkm x 175km/ngdy = 168,940 VND/ngay + Tram d p CNG Nguyen HO'u Canh: Cdy xdng Hoang Nguyfin, 220B Dipn Bifin Phu, P 25, Qugn Binh Thpnh, Tp Ho Chi Minh + Trong dd, chi phi diu tu bO kits chuyin ddi cho xe Id: 64,000.000 VND/xe (tpi ddy gia sii giam tru chi phi thilt k l cua xe Id 12,000,000 VND/mau + Tram d p khf CNG Tdn Kifin: Cdy xdng Thanh Hipp Phdt tren quic lp IA, s l 4B/12A, I p 02, xa Tan Kifin, H Binh Chdnh Tp H i Chi Minh 22* NLN-105* 5/2012 + Tram d p CNG Nguyfin An Ninh, s l 449 Nguyfin An Ninh, Phudng 9, Vung Tdu, Tinh Bd Ria -Vung Tdu Tii triln khai su dung CNG cho dfin thdi dilm nay, san lupng CNG cung d p cho 295 xe k l trfin la 700,000 kg CNG (tii 05/2010 din 02/2012) Trong giai doan ddu, san lupng kht CNG edn it tf lfi vdi lupng xe chuyin ddi, nhung den thdi dilm hien tai san lup'ng tifiu thu CNG binh qudn hang thang vao khoang 55,000 Kg CNG Theo bang 24, ta cd ti le tuang duang giiia Kg CNG/ Lit xang nhu sau: K=(7 21 +7 23)/(11.86+ 12 14) = 0.60 Kg CNG/LitXang Nhu vay vdi san lugng 55,000 kg CNG tuang duang vdi: 55,000/0.60 = 91,667 Lit Xang Chl phi eho nhifin lipu CNG hing thang' 55,000 ' 24,690 = 1,357,950,000.00 VND Chi phi cho nhifin lieu xang hang thang 91,667 * 22,900 = 2,099,174,300 00 VND Chl phi tilt kifim hing thdng: 2,099,174,300-1,357,950,000 = 741,224,300.00 VND Nhu vay, vdi san lugng tieu thu lugng CNG hifin tai, khdng nhung gdp phin giam thilu d nhifim mdi trudng ma eon tilt kiem hdng thdng han 740 tneu VND, ngodi cung giam phin phu thudc vao lupng xang nhap khiu III.3 D I xudt khu vyc su- dung CNG tai Viet Nam: Mien nay, ngudn thien nhien dugc dua vao bd thdng qua Nha may Dinh Cd, Ba Rja Vung Tau Tii Nha may Dinh Cd thifin nhifin dugc dan din cac Tram me (Tram nen CNG) thdng qua hp thing dudng dng hien hO'u tai khu vuc Vung Tau - Tp Hd Chi Minh, tii dd chung ta mdi c6 thfi san xult dugc CNG Do dac thu cua ITnh vuc CNG, eac dia dilm tifip nhdn, sii dung CNG nfin ndm pham vi ban kinh 200Km ddi vdi cac Tram nen, Tren eo sa dd, chiing tdi dfi xult cac khu vuc tap trung sii dung va khai thac CNG diing Idm nhien lieu cho phuang tifin giao thdng vpn tai rifin tap trung tai cac phd vd tinh sau Tp Hd Chf Minh, Ddng Nai, Bd Rja Vung Tau, Binh Duong, Long An Trong thdi gian tdi (vao ndm 2014) lugng khu vuc phia Bae dugc dua vao bd thi CNG cung cd t h l ap dung cho cac tinh thdnh phd nhu Hd Ndi, Hai phdng, Thai Binh, Nam Dinh, Hd Nam, Hai Duong Ngoai ra, tuang lai gin vipc su dung khf thifin nhien dung Idm nhifin lieu cho phuang tifin giao thdng van tai cdn cd t h l phdt trien rdng han nu'a thdng qua thifin nhien hda Idng (LNG Liquied Natural Gas), vdi ban kinh len din 600Km IV.DE XUAT KIEN NGHI Nhin chung, ddng co diing CNG ed rdt-nhifiu hua hen ddi vdi td hoat ddng hay vung ven do, nhung khu vyc md tinh trpng d nhifim mdi trudng phuang tifin vpn tai gdy cang trd nen trim trpng O mpt sd khu vyc trfin thfi gidi, chinh phu bit budc cdc hang taxi phai diing CNG cho vipc di lai dja phuang dd Dya trfin nhu'ng Igi fch rd ret ve tinh kinh t l , tang tuoi tho cho dpng ca, giam thilu mire dp nhilm mdi trudng cua nhien lieu CNG, Viet Nam cung nen nhanh chdng triln khai cac chinh sach d l hd tra vipe phdt triln CNG - mdt nhifin iifiu thay thl mdi vdi cae ehinh sach nhu: - Nha nudc cd cdc chinh sach mifin thul nhdp khiu cdc thiet bj chuyen diing CNG nhu edc nudc Han Qudc, Thai Lan la 0% - Co chinh sach thul uu dai khde dfi khuyen khich chu phuang tifin sii dung CNG Idm nhifin lifiu cho xe nhu mifin thul mdi trudng, uu tifin vdo cac khu dd thj, ho trg 50% chi phi thilt bi bd chuyin ddi sii dung CNG cho ddng ca - Quy hoach ca sd tdng ddng bd, phyc vy vifie lap dat tram d p CNG ting thl quy hoach dd thi vd cay xang - Giam thul thu nhap Doanh nghifip tif 25% xudng 10% cho cd nha ddu tu ldp ddt tram CNG phyc vuc hfi thing giao thdng van tai, cung nhu cdc Cdng ty van tai sii dyng CNG lam nhien lipu chinh Abstract: The thesis has focused on develop the fundamental of (he application CNG (Compressed Natural Gas) to gasoline vehicle engine We converted 02 vehicles to using CNG as Toyota Innova and Toyota Corolla Altis and measured technical parameters and compare the results of using CNG and Gasoline also, CNG fuel cost has decreased more than 35% compared to using gasoline The project is being mass carried cut in Hochiminh City and Bafia - Vung Tau province with over 300 vehicles converted to CNG by Petrovietnam Southern Gas J S.C We also proposed some policies to Government and Authonzed Office for supporting to develop CNG nationwide as new fuel to reduce environmental pollution ... Tii triln khai su dung CNG cho dfin thdi dilm nay, san lupng CNG cung d p cho 295 xe k l trfin la 700,000 kg CNG (tii 05/2010 din 02/2012) Trong giai doan ddu, san lupng kht CNG edn it tf lfi vdi... lup''ng tifiu thu CNG binh qudn hang thang vao khoang 55,000 Kg CNG Theo bang 24, ta cd ti le tuang duang giiia Kg CNG/ Lit xang nhu sau: K=(7 21 +7 23)/(11.86+ 12 14) = 0.60 Kg CNG/ LitXang Nhu... binh CNG dung tich 90 lit thSng thud''ng chua dugc 14,3 kg Do d6, v6i mue d6 tieu thu nhien lieu CNG nhu tr§n, ta co t h l dam bao edc phuang tien van chuyin vdn thuan tipn cho m5i ldn npp CNG