Tgp chi Khoa hgc Tniang Ggi hgc Cdn Tha Phdn A: Khoa hoc Tu nhiin. Cong nghe vd Mdi trudng: 25 (2013}: 8-12
Tap chf Khoa hpc - Oai hoc Can Thd website: sj.ctu.edu.vn
NGHIEN CUtJ ANH HlTdNG CUA CHAT KHANG OXY HOA DEN SlT THAY D O I THANH PHAN DAU DIESEL SINH HOC TONG HOP TlT MOf CA TRA, CA BASA Nguyin Van Dat', Toshihiro Hirotsu' va Shinichi Goto'
'Khoa Khoa hgc TV nhiin, Truong Dgi hgc Can Tha
^Research Center for New Fuels and Vehicle Technology. AIST. Tsukuba, Japan
Thong tin chung:
Ngdy nhdn: 30/07/2012 Ngdy chdp nhdn: 25/03/2013
Title:
Study of some affecting fators on the change in fam- acid profile of Catfish fat based biodiesel
Tirkhda:
Diesel sinh hgc, thdnh phdn acid beo
Keywords:
Biodiesel, fatty acid profile
ABSTRACT
The effects of two types of synthetic antioxidant (Ecotrve^^ and BHT) on the chemical compositions of Catfish fat based biodiesel (FAME) have been evaluated. Gas Chromatography Mass Spectrometry (GC- MS) analytical results showed that the compositions of fatty acid methyl esters were not significantly changed by the used antioxidants during storage for one month at room temperature.
TOM TAT
Anh hudng ciia hai chdt khdng oxi hoa long hgp (Ecotive^ vd BHT) din thanh phdn fatty acid methyl esters cda biodiesel tong hgp tir md cd tra. cd basa (FAME) dd dugc ddnh gid trang nghien cuu nay. Kit qud phdn tich GC-MS cho thdy thdnh phdn fatty acid methyl esters it thay doi khi co mat hai chdt khdng oxi hoa nghien ciru sau mgt thdng ton trii FAME tgi nhiit dg f^ong.
1 DATVANDfe
Ngay na\'. the gidi dang phai ddi mat su thay ddi lien tuc gia cua ngudn nhien lieu hda thach.
dac biet ta ddu md, do nhimg ngudn nang lugng nay ngay cang can kiet va Iugng tieu thu ngay cang lang. Dieu nay dd ddn den viec phai tim ngudn nhien Heu de thay the. Phan img giira ddu thuc vat hodc ma dgng vat va mdt alcohol vdi sir cd mat ciia base manh tao ra mot loai hgp chat hda hgc mdi ggi la biodiesel (Ayhan Demirbas, 2009).
Tuy nhien, mgt trong nhung bdt lgi Idn nhat cua viec dung dau diesel sinh hgc (biodiesel), la tinh bin o?d hda cua loai nhien lieu nay kem han nhilu so vdi ddu diesel do ham lugng
methyl esters chua bao hda cao. Dac biet la thanh phdn methyl esters chua bao hda vdi nhieu lien ket pi trong phdn hi (poly- unsaturated methyl esters) chiing di dang bi oxi hda nhu methyl linoleate (Cig^) va methyl linolenate (Cigs) ddn den hinh thanh cac acid, aldehyde, ester, ketone, peroxide va alcohol.
Nhimg chat nay khdng nhimg anh hudng den chat lugng cua biodiesel ma cdn gay ra nhieu tac hai cho ddng ca (Monyem A. 2001). Ciing chinh vi ly do nay, nen viec dung dau diesel sinh hgc tai Viet Nam cdn han che ben canh mdt nguyen nhdn khdc la gia thanh san xuat cao cua loai nhien lieu nay. Qud trinh oxi hda biodiesel dugc gidi thich theo ca che nhu sau:
Tap chi Khoa hoc Trudng Dai hoc Cdn Tha Phdn A: Khoa hoc Tu nhien. Cdngnghi\a Moi mi&ng: 25 (2013): S-f2
Khoi mao Phat trien m^ch Ngat mach
RH R" -. O2 ROO'+RH R' + R ROO' + ROO"
R- (a) ROO' (b) ROOH + R' (c) R-R (d) San pham
b^n (e)
Stf do 1: Co'che qud trinh oxi hoa biodiesel So dd 1 minh hga co che qua trinh oxi hda biodiesel, trong dd, RH la phdn tir FAME, R* ia goc tu do, ROO" la goc tu do peroxide, ROOH ia hydroperoxide, R-R la san phdm ciia qua trinh oxi hda. Trong qua trinh oxi hda, phan tir FAME hinh thanh gdc tu do (phan ung a). Gdc tu do nay ngay lap tiic phan ung vdi oxi hinh thanh goc tu do peroxide (phan ung b), gdc tu do nay nhanh chdng tao ra gdc tu do mdi tir phan tir FAME (phan iing c). Phdn ung se tilp tuc cho den kh! cac goc tu do phan ung vdi nhau (phan iing d) hoac cac gdc ty do peroxide
(phdn ung e) phan ung vdi nhau d giai doan ngat mach. Ket tiiiic qua trinh nay se hinh thanh acid, aldehyde, ketone,... lam cho nhihig ddc ti'nh ly hda cua biodiesel nhu: dd nhdt dgng hgc, chi sd acid (AV) cung nhu do bSn oxi hda thay ddi.
Chdt khang oxi hda la nhiJng chdt \XQ chl qua trinh oxi hda. Cd hai kieu chat khang oxi hda dugc bilt (Pospisil, 1990): cat mach day chuyin va phan hiiy hydroperoxide. Chdt khang oxi hda cd vai tro cdt mach day chuyen thudng cd hai loai ia phenolic va amine. Hdu het nhihig cdng trinh nghien cuu deu tap trung vao loai hgp chdt khang oxi hda dang phenolic. Ca chl d l nghi cho loai chdt khang oxi hda nay nhu sau:
ROO* + AH A*
R O O H + A San pham ben Tir CO che tren cd the thdy rang, chat khang oxi hda chua mgt nguyen tu H kem ben dl bi lay bdi gdc tu do. Cudi cimg chat khang oxi hoa nay se hinh thanh dang bin vung hoac tiep tuc phan U'ng de tao thanh san pham ben.
Hinh 1: Minb hpa co* che khir glc tur do ciia chat khing oxi h6a dang phenolic Ngudn: Sarin. (2007)
Hinh 2: Minh hpa co* che khii- goc t\r do ciia chat khang oxi hda d^ng amine Ngudn- Sarin. (2007)
Muc tieu Ciia cdn^ trinh nay la nghien cmi dnh hudng ciia hai chat khang oxi hda tdng hgp
C ^
o i l
la Ecotive va BHT, thai gian tdn tru va nhift do ton trir dSn thanh phin hoa hgc cua dau
Tgp chi Khoa hgc Trudng Dgi hge Cdn Tha Phdn .4: Khoa hoe Tu nhien. Cong nghe vd Mdi ti-uong: 25 (2013): 8-12
diesel sinh hgc tdng hgp tir ma ca tra, ca basa, gdp phdn vao viec tim ra nhimg ludn chung khoa hgc ve ban chat ciia qua trinh oxi hda ddu diesel sinh hgc.
2 PHU'ONG PHAP NGHIEN C t U 2.1 Vat lieu
Md ca tra, ca basa dugc mua tir Cdng ty cd phdn Ky Nguyen Xanh, khu cdng nghiep Tra ndc, q u ^ Ninh Kilu, thanh phd Cdn Tha.
Hda chat diing trong tdng hgp va phdn tfch cd xudt xu tir Merck, Due va Fluka, Nhdt.
2,6-Di-/ert-butyl-/>-cresol (Butylated Hydroxy Toluene, BHT) va Ecotive^" dugc mua tu Seiko Company, Nhat Ban.
2.2 Phircmg phap nghi€n cuu
2.2.1 Phiromg phdp tong hap FAME tit ma ca tra, cd basa
Biodiesel dugc tdng hgp tii ma ca tra, ca basa bang phuang phap khudy tir gia nhiet (Nguyen Van Dat, 2009).
2.2.2 Phdn tich linh chdt hoa ly cHa ddu nguyen lieu vd biodiesel
Do nhdt ddng hgc (mm"/s) dugc xac dinh d 40 °C, bang each do thdi gian de mgt the tich chdt long xac djnh chay qua mot mao quan thuy tinh dudi tac dung cua trgng lire. Dg nhdt ddng hoc la kit qua tinh dugc tir thdi gian chay va hdng sd tuang irng cua nhdt k§ Ostwald.
Ham iugng nude (mg/kg) dugc xac djnh bdng each diing thiet bi 831 KF coulometer (Metrohm) theo tieu chuan BS EN ISO 12937:2001.
Chi sd acid (mg KOH/g) dugc xac dinh bdng each diing thilt bi chuan dg the tu d^ng GT-lOO lien kit vdi he thdng bam mdu tu ddng GT-07 (Mitsubishi Chemical Analytech Co., Ltd., Jj^an) theo chudn JIS K 0070-1992.
Chi sd iod (g h /I OOg) dugc xac dinh bdng phuong phap chudn do the tich dung dich phdn ling cua ddu ho^c nhien lieu sinh hgc vdi dung dich Wijs (CI3I/I2 trong dung dich acid acetic) theo tieu chudn JIS K0070-1992.
Chi sd peroxide (meq/kg) dugc xac dinh bdng each dung thiet bi chudn do the (Titrado
809, Mefrohm) theo tieu chudn BS ISO 27107:2008.
2.2.3 Nghien cuu dnh hucmg ctia chdt khdng oxihoa
FAME dugc trdn vdi cdc chdt khang oxi hda BHT va Ecotive™ vdi ndng do 1000 ppm.
Mdu dugc khao sat do bin oxi hda d d nhiet dd phdng sau mdt thang tdn tru. Mdu dugc bdo quan trong cac tu dn nhiet IWAKI incubator (ASAHl TECHNO GLASS).
2.2.4 Phan tich thdnh phdn acid beo cua FAME Phan tich thanh phdn FAME tren may sdc ky ghep khdi phd (GC-MS 2010, Shimadzu, Co., Nhat Ban) vdi cgl (30m x 250tun x 0,25pm).
Lugng mau I |.iL dugc bam tu ddng (OAL-20i, Shimadzu); nhiet do bom mdu 250°C; tdc do ddng khf mang (He) 2 mL/phiit, theo chuang trinh nhiet phan tfch mdu ddu beo nhu sau:
nhiet do ddu fO^C, gia nhidt 5°C/phut cho din 260''C, giit 10 phiit. Thanh phdn acid beo dugc xac dinh thdng qua cac dinh ciia phd dd tuong umg vdi khdi lugng phdn tu cd trong du lieu di kem vdi he thdng Shimadzu GC-MS.
3 K E T QUA VA THAO LUAN 3.1 Nhirng tinh chat hda ly cua m& ca
nguySn liSu va san pham FAME M a ca nguyen lieu va san pham FAME dugc tien hanh danh gia chdt lugng thdng qua mdt sd chi tieu hda ly ca ban nhu do ben oxi hda, chi sd acid (AV), chi so peroxide (PV), chi sd Iodine (IV), do nhdt ddng hgc d 40 "C va ham lugng nude. Ket qua dugc trinh bay trong Bang 1.
Bang 1: Tinh chat hoa ty ciia m& ca nguySn lifu va FAME
Tinh chat boa ly M&ca FAME 7.33 1.07
5.40 Dp ben oxi hoa theo Rancimat,
gid
Dp bin oxi hoa theo PetroOXY, gid
Chi s6 acid (AV), mg KOH/g 0.98 0.10 Chi so peroxide (PV), meq/kg 1.10 10.20 Chi s6 iodine (rV),gW100g 44.42 34.00 Do nhdt dpng hpc o 46''C, mrnVs 38.86 4.62 Ham lugng nude, ppm 1283.70 380.50
Ham lugng HCOOH, ppm 1.40
Ecotive™ 1000 ppm) va (.FAME 1000 ppm) sau mot thang t6n tru tai i phong duoc ttinh bay torn tit a Bang 3.
Bang 3: Thanh phan acid bto chinh ciia FAME, % BHT i nhiet dp
T£n acid So carbon: EcotiveTM So C < : 1000 ppm
BHT 1000 ppm Tap chi Khoa hoc Tmdng Bai hoc Can Tha Phdn A: Khoa hoc Tu nhien. CongngM vo Mdi trudng. 25 (2013): S-U
Tu Icet qua tren cho thiy do bSn oxi hoa cila FAME (5.4 gio) theo phuang phap Rancimat khong thoa tieu chuin EN (>6 gio) hay JIS (>I0 gio). D i k nay cOng phii hop voi thanh phin cua FAME phan tich duoc vdi da s6 la ester ciia nhimg acid beo chua no nen chung de bi oxi hoa (Bang 2). Cac thong s6 vS AV, IV, dp nhdt dong hoc d 40 "C, ham Iugng nude cua FAME ihl thda duoc cac tieu chuan hien hanh.
Ngoai ra, k8t qua phan tich HPLC (High- performance liquid chromatography) ciing cho thiy trong FAME cd mot ham luong nhd HCOOH, day la acid mach ngan, san phSm cua qua trinh oxi hda FAME.
3.2 Thanh p h i n FAME
Ket qua phan tich GC-MS cho thay thanh phin acid beo cua FAME chu y6u la C12 dgn C20. Thanh phan Cigi chiem nhieu nhat (40.13%) tiep dSn la C.^o (32.41%). Tdng hai thanh phan nay chiem den 72.54%. Tdng ham lugng cua cac ester cd da ndi ddi chi chiem 7.29%.
BSng 2:Thanb phin acid beo chinb ciia FAME, %
Acid tridecanoic Acid palmitic Acid Stearic Acid oleic Acid linoleie Acid eicosenoic Acid eicosadienoic Acid eicosatrienoic Arachidonic acid
13:0 16:0 18:0 18:1 18:2 20:1 20:2 20:3 20:4
4.65 27.44 13.20 34.80 9.00 0.02 0.41 0.16 0.17
4.46 27.40 13.43 34.09 8.73 1.69 0.40 0.17 0.16
Ten acid So carbon:
SoC=C Acid launc
Acid myristic Acid palmitic Acid palmitoleic Acid stearic Acid oleic Acid linoleie Acid eicosenoic Acid eicosedienoic Acid eicosatrienoic Arachidonic acid Acid beo bSo boa Acid beo chiia mot moi doi C=C
Acid b ^ chua nhi^u moi doi C=C
Thdnh phan khac
12:0 14:0 16:0 16:1 18:0 18:1 18:2 20:1 20:2 20:3 20:4
0.12 4.48 32.41 1.40 11.29 40.13 6.02 1.48 0.49 0.55 0.23 48.30 41.61 7.29 2.80 3.3 Anh hirdng cua chat khang oxi boa den
thanh phan FAME sau mgt thang liru trir t^i nhiet do phong
Thanh phdn acid beo chi'nh cua hon hgp gdm FAME va chdt khang oxy hda (FAME +
TiJr kit qua d Bang 3 cho thay, bang each sir dung hai chdt khang oxi hda Ecotive^*^ va BHT d ndng do 1000 ppm, sau khoang thdi gian liru trQ mdt thdng tai nhiet do phdng, ham lugng (%) methyl ester cua cac acid beo chinh ciia FAME hau nhu thay ddi khdng dang ke. Ket qud nay cho thdy, viec sijr dung hai chat khang oxi hda Ecotive^"^ va BHT d ndng do 1000 ppm cd thi giup cai thien do bin oxy hda ciia biodiesel tong hgp tir md ca tra, ca basa.
4 K E T LUAN
Da tdng hgp dugc ddu diesel sinh hgc tu m9 ca tra, ca basa dat dugc yeu cau v l chdt lugng theo tieu chudn cua ASTM, EN va JIS. Tuy nhien, dp ben oxi hda chua dat dugc cac yeu cau cua tieu chuan EN va JIS. Viec su dung hai chdt khang oxi hda Ecotive^'^ va BHT d ndng do 1000 ppm giup duy tri khd tdt thdnh phan cac methyl ester ciia cac acid beo chinh sau mflt thang tdn tru sdn phdm biodiesel tai nhi|t d?
phdng. Ket qua nay cho thdy hai chdt khang oxy hda nghien cuu cd kha nang cai thien do ben oxy hda ciia biodiesel tdng hgp tiJr md ca tra, ca basa.
L 6 I CAM TA
Cdc tac gid chdn thanh cdm an Trung tam nghien cuu v l ky thuat co gidi va nhien lieu mdi (NFV), Vien AIST, Tsukuba, Nhat Ban thdng qua su ho trg tai chinh tiJc du an nghien cuu nhien lieu sinh hgc do td chuc NEF tai trp da cung cdp phuang tien va nhimg dilu kien
Tgp chi Khoa hoc Trudng Dai hoc Cdn Tho Phdn A: Khoa hoc Tu nhien. Cong nghe rd Moi trirdng: 25 (2013) • 8-J2 nghien ciru tdt nhit. Dac biet, chung tdi xm
chan thanh cam on cac cgng sir cua nhdm nghien ciiu (Tanaka, Kaitsuka) tai trung tam nghien ciru NFV da giup do va ho trg ky thuat phan tich de chiing tdi hoan thanh nghien cuu nay.
TAI LIEU THAM KHAO
1. Ayhan Demirbas, 2009. Biofuels: Securing the Planet's Future Energy Needs. Springer 2. Monyem A, Van Gerpen JH, 2001. The effect
of biodiesel oxidation on engine performance and emissions. Biomass Bioenergy 2001;
20:317-25.
3. Nguyen Van Dat, 2009. A Study towards the Effect of Antioxidants on Vietnamese Catfish Fat Biodiesel, Collected Papers of Invited Research. Asia Biomass Energy Researchers Program 2009, New Energy Foundation, Japan.
Pospisil, J.;Klemchuk, P.P. (editors), 1990.
Oxidation Inhibifion in Organic Materials, Volume I, CRC Press.
Ramos, L.P., A.K. Domingos, E.B. Saad, W.W.
D. Vechiatto and H. M. Wilhelmc, 2007. The Influence of BHA, BHT and TBHQ on the Oxidation Stability of Soybean Oil Ethyl Esters (Biodiesel). J. Braz. Chem. Soc. 18: 416-423.
Sarin, R., M. Sharma, S. Sinharay and R.K.
Malhotra, 2007. Jatropha-Palm biodiesel blends: An opdmum mix for Asia. Fuel 86:
1365-1371.
