[123doc.vn] Luan Van Cong Nghe Hoa Nghien Cuu Tong Hop Dau Diesel Sinh Hoc Tu Ba CA Phe Phe Thai

7/25/2019 [123doc.vn] Luan Van Cong Nghe Hoa Nghien Cuu Tong Hop Dau Diesel Sinh Hoc Tu Ba CA Phe Phe Thai

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BGIO DC V O TO

TRNG I HC CN TH

KHOA KHOA HC TNHIN

LUN VN TT NGHIP I HC

NGHIN CU TNG HP DU DIESELSINH HC TB C PH PHTHI

CN BHNG DN SINH VIN THC HINTS. Bi ThBu Hu Bi Lin Khoa

MSSV: 3077158Ngnh: Ha Hc K33

Thng 5 - 2011


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TRNG I HC CN TH CNG HA X HI CHNGHA VIT NAM

KHOA KHOA HC TNHIN c lp-Tdo-Hnh phc

BMN HA HC

Cn Th, ngy thng nm 2011

PHIU NGHTI TT NGHIP CHO SINH VIN

NM HC 20102011

1.Cn bhng dn: Ts. Bi ThBu Hu.

2.Tn ti: NGHIN CU TNG HP DU DIESEL SINH HC TB CPH

3.a im thc hin: phng th nghim hu c chuyn su Khoa Khoa Hc TNhinTrng i Hc Cn Th.

4.

Slng sinh vin thc hin: 1

5.Hv tn sinh vin thc hin: Bi Lin Khoa (MSSV: 3077158).

6.Mc ch yu cu: Nghiu cu qui trnh tng hp biodiesel tb c ph quy mphng th nghim.

7.Ni dung chnh v gii hn ca ti: ti gm 4 phn:

Chng 1: TNG QUAN

Chng 2: PHNGTIN V PHNG PHP NGHIN CU

Chng 3: THC NGHIMChng 4: KT QUV THO LUN

Chng 5: KT LUN V KIN NGH

8.Cc yu cu htr: Trang thit b, dng cth nghim v kinh ph thc hin ti.

9.Kinh ph dtr cho vic thc hin ti: 800.000 ng.

Sinh vin ngh

(K tn v ghi r htn)

Bi Lin Khoa

kin ca bmn kin ca cn bhng dn

Ts. Bi ThBu Hu


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Trng i Hc Cn Th Cng Ha X Hi ChNgha Vit Nam

Khoa Khoa Hc TNhin c lpTDoHnh Phc

BMn Ha Hc


NHN XT V NH GI CA CN BHNG DN1.Cn bhng dn: Ts. Bi ThBu Hu

2.Tn ti: NGHIN CU TNG HP DU DIESEL SINH HC TB CPH PHTHI

3.Sinh vin thc hin: Bi Lin Khoa (MSSV: 3077158).

4.Lp: CNhn Ha Hc K33.

5.Ni dung nhn xt:

a.Nhn xt vhnh thc ca lun vn tt nghip: .....................................................

...........................................................................................................................................

...........................................................................................................................................

b.Nhn xt vni dung ca lun vn tt nghip (nghghi chi tit v y ): ......

...........................................................................................................................................

...........................................................................................................................................

Nhng vn cn hn ch: ..................................................................................

...........................................................................................................................................

...........................................................................................................................................

c.Nhn xt i vi sinh vin thc hin ti: .............................................................

...........................................................................................................................................

...........................................................................................................................................

d.Kt lun nghv im: .........................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................Cn Th, ngy thng nm 2011

Cn bchm hng dn

Ts. Bi ThBu Hu


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Trng i Hc Cn Th Cng Ha X Hi ChNgha Vit Nam

Khoa Khoa Hc TNhin c lpTDoHnh Phc

BMn Ha Hc


NHN XT V NH GI CA CN BPHN BIN

1.Cn bhng dn: Ts. Bi ThBu Hu

2.Tn ti: NGHIN CU TNG HP DU DIESEL SINH HC TB CPH PHTHI

3.Sinh vin thc hin: Bi Lin Khoa (MSSV: 3077158).

4.Lp: CNhn Ha Hc K33.

5.Ni dung nhn xt:

a.

Nhn xt vhnh thc ca lun vn tt nghip: .....................................................

...........................................................................................................................................

...........................................................................................................................................

b.Nhn xt vni dung ca lun vn tt nghip (nghghi chi tit v y ): ......

...........................................................................................................................................

...........................................................................................................................................

Nhng vn cn hn ch: ..................................................................................

...........................................................................................................................................

...........................................................................................................................................

c.Nhn xt i vi sinh vin thc hin ti: .............................................................

...........................................................................................................................................

...........................................................................................................................................

d.Kt lun nghv im: .........................................................................................

...........................................................................................................................................

...........................................................................................................................................

...........................................................................................................................................


Cn bchm phn bin


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LI CAM OAN

Tt c nhng d liu v s liu s dng trong ni dung bi lun vn c ti

tham kho nhiu ngun khc nhau v c ghi nhn tnhng kt quth nghim m

ti tin hnh. Ti xin cam oan vstn ti v tnh trung thc khi sdng nhng d

liu v sliu ny.

Bi Lin Khoa


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LI CM N

Sau hn ba thng thc hin lun vn tt nghip, em hc hi c nhiu kinthc qu bu v lnh vc m em nghin cu. hon thnh lun vn chnh l nh

nhng iu bch m Thy C truyn t cho em trong sut nhng nm thng i

hc v l nn tng tri thc em ttin bc vo i.

Em xin chn thnh cm n qu Thy C ca Trng i Hc Cn Th ni chung

v Thy C Khoa Khoa Hc TNhin ni ring. c bit em xin gi li bit n su

sc n C Bi ThBu Hu, ngi tn tnh hng dn trong tng chn ng

nghin cu thc hin ti.

Em cng gi li cm n n bn b v gia nh gip , ng vin, to iu

kin cho em vtinh thn ln vt cht em hon thnh lun vn ny.

Em xin by tlng bit n n tt cmi ngi.


Bi Lin Khoa


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LU N VN T T NGHIP Cn bhng dn: TS. Bi ThBu Hu

Sinh vin thc hin: Bi Lin Khoa i

GII THIUHin nay, th gii v ang phi i mt vi hai vn ln l hin trng

nhim mi trng do lng rc thi kh ln v tnh trng khan him ngun nhin liu

du m. Chnh v vy, vn c t ra l nghin cu tn dng ngun rc thi snxut ra nhin liu sinh hc thay thcho ngun nhin liu truyn thng.

Nhn vthc trng ngun nng lng tiu thtrn thgii ngy nay th du th

v kh tnhin l ngun nng lng quan trng nht. Cc ngun ti nguyn ny c

gii hn v khng ti to c. Nu cc ngun ny c sdng vi mc hin nay

th khnngthiu ht ngun nguyn liu c thxy ra. Hn na, vic sdng rng ri

nhin liu du mgy ra vn nhim mi trng. Do , c squan tm n

mt sngun nng lng thay th, trong diesel sinh hc l mt trong nhng nhin

liu thay thkh tt v thn thin vi mi trng. Tuy nhin, cc nghin cu tng hp

diesel sinh hc hin nay ch yu t cc ngun nguyn liu du m ng thc vt

nhng cha cp nhiu vdu bo tb c ph, mt ngun nguyn liu phthi kh

di do v rtin. Hng nm, thgii sn xut hn 2,72 tKg c ph. Cc nh khoa

hc c tnh rng, tb c ph qua sdng ny c thtng hp c khong 1287

triu lt du diesel sinh hc ng gp vo ngun nhin liu ca thgii.


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Sinh vin thc hin: Bi Lin Khoa ii

MCLC

CHNG 1 TNG QUAN TI LIU .......................................................................... 1

I LIPID ......................................................................................................................... 1

I.1 Khi nim vlipid ............................................................................................... 1

I.2 Phn loi v lipid ................................................................................................. 2

I.2.1 Da vo phn ng x phng ha..2

I.2.2 Da vo ha tan...2

I.2.3 Da vo thnh phn cu to..2

I.3 Chc nng ca lipid ............................................................................................. 3

I.4 Tnh cht chung ca lipid .................................................................................... 3I.4.1 Tnh cht vt l.3

I.4.2 Tnh cht ha hc.4

II CC PHNG PHP THU LY DU BO TRONG B C PH ................... 6

II.1 Tch chit bng dung mi hu c...................................................................... 6

II.2 Tch chit bng CO2lng siu ti hn .............................................................. 7

II.3 Tch chit bng enzyme ..................................................................................... 7

II.4 p bng my ....................................................................................................... 7III BIODIESEL ............................................................................................................ 8

III.1 Nhin liu diesel ............................................................................................... 8

III.2 S lc v biodiesel .......................................................................................... 8

III.2.1 Khi nim ...8

III.2.2 Lch shnh thnh v pht trin ca biodiesel.10

III.2.3 Tnh hnh sdng biodiesel trn thgii v Vit Nam...10

III.3 Cc chtiu ha l ca biodiesel .................................................................... 11

III.3.1 nht .11

III.3.2 ChspH..11

III.3.3 Tro sulfate.11

III.3.4 Lu hunh,,,.11

III.3.5 Trscetane.....12

III.3.6 Chsacid....12 III.3.7 Glycerol tdo...12


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Sinh vin thc hin: Bi Lin Khoa iii

III.3.8 Glycerol tng....12

III.3.9 Hm lng tro phosphorus,,,12

III.3.10 Hm lng nc ln vo nhin liu...13

III.4 Nhng u, nhc im ca biodiesel ............................................................ 13

III.4.1 Nhng u im khi sdng biodiesel cho ng c diesel......13

III.4.1.1 Vmt mi trng13

III.4.1.2 Vmt kthut.14

III.4.2 Nhc im ca biodiesel...15

III.5 Cc phng php ha hc sdng trong tng hp biodiesel ........................ 15

III.5.1 Phn ng transester ha lipid...15

III.5.1.1 Cc phng php thc hin phn ng transester ha lipid16III.5.1.2 Xc tc sdng trong phn ng transester ha16

III.5.2 Phn ng ester ha acid carboxylic.19

III.6 Tng hp biodiesel da trn phn ng transester ha c sdng xc tc kim

................................................................................................................................ 21

III.6.1 i vi du thc vt hoc m ng vt c hm lng acid t do

thp............................................................................21

III.6.2 i vi du thc vt hoc m ng vt c hm lng acid bo t do

cao. 22

III.7 Tim nng sn xut biodiesel tb c ph ..................................................... 23

CHNG 2 PHNG TIN V PHNG PHP NGHIN CU ......................... 24

I NI DUNG NGHIN CU .................................................................................... 24

II PHNG TIN NGHIN CU ........................................................................... 24

II.1 Thit bv dng c ........................................................................................... 24

II.2 Ha cht ........................................................................................................... 24

II.3 Nguyn liu ...................................................................................................... 25

III PHNG PHP NGHIN CU ......................................................................... 25

III.1 Phng php ly trch du bo tb c ph ..................................................... 25

III.1.1 Phng php chit soxhlet ....................................................................... 25

III.1.2 Phng php ngm dm ........................................................................... 25

III.2 Xc nh cc chsha l ca du bo trch ly tb c ph phthi ........... 26


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Sinh vin thc hin: Bi Lin Khoa iv

III.2.1 Xc nh m b c ph v hm lng cht bay hi............................. 26

III.2.1.1 Nguyn tc.26

III.2.1.2 Tin hnh...26

III.2.1.3 Tnh kt qu...26

III.2.2 Chsacid (IA) ........................................................................................ 26

III.2.2.1 ngha...26

III.2.2.2 Nguyn tc.26

III.2.2.3 Tin hnh...26

III.2.2.4 Tnh kt qu...27

III.3 Tng hp biodiesel tdu bo ca b c ph phthi ................................... 27

CHNG 3 THC NGHIM..29 I Giai on ester ha .................................................................................................. 29

I.1 Cch btr th nghim: ...................................................................................... 30

I.2 Tin trnh thc hin ........................................................................................... 30

I.3 Tin trnh ra ..................................................................................................... 30

II Giai on transester ha ......................................................................................... 31

II.1 Cch btr th nghim ...................................................................................... 31

II.2 Tin trnh thc hin .......................................................................................... 31

II.3 Tin hnh phn ng .......................................................................................... 31

II.4 Tin trnh ra.................................................................................................... 32

III Tin trnh lm kh sn phm ................................................................................. 32

IV nh gi cht lng sn phm biodiesel .............................................................. 32

CHNG 4 KT QU- THO LUN ...................................................................... 33

I CC CHSHA L ........................................................................................... 33I.1 m ca b c ph phthi v hm lng cht bay hi ................................ 33

I.2 Hiu sut ly trch du bo tb c ph phthi................................................ 33

I.2.1 Phng php ngm dm..33

I.2.2 Phng php trch soxhlet.33

I.2.3 Nhn xt...33

I.3 Chsacid ca du bo ..................................................................................... 34

II QUY TRNH IU CHBIODIESEL TB C PH ..................................... 34


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Sinh vin thc hin: Bi Lin Khoa v

II.1 Phn ng ester ha ........................................................................................... 34

II.1.1 nh hng ca lng methanol....34

II.1.2 nh hng ca nhit phn ng.36

II.1.3 nh hng ca thi gian phn ng37

II.1.4 nh hng lng acid H2SO4................................................................39

II.1.5 iu kin ti u ca giai on ester ha....40

II.2 Phn ng transester ha ................................................................................... 41

II.2.1 nh hng ca lng methanol....41

II.2.2 nh hng ca nhit phn ng....43

II.2.3 nh hng ca thi gian...44

II.2.4 nh hng lng xc tc KOH.46 II.2.5 iu kin ti u ca giai on transester ha....48

II.3 nh gi cht lng sn phm biodiesel iu chc .................................. 49

CHNG 4 KT LUNKIN NGH ..................................................................... 51

I KT LUN .............................................................................................................. 51

II KIN NGH ............................................................................................................ 51

TI LIU THAM KHO ............................................................................................. 52


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Sinh vin thc hin: Bi Lin Khoa vi

MC LC CC BIU BNGBng 1 So snh mt schtiu gia biodiesel (RME) v diesel .................................... 9

Bng 2 Cc yu tcnh ............................................................................................ 35

Bng 3 nh hng lng methanol n chsacid ..................................................... 35

Bng 4 Cc yu tcnh ............................................................................................. 36

Bng 5 nh hng ca nhit phn ng n chsacid ........................................... 37

Bng 6 Cc yu tcnh ............................................................................................ 38

Bng 7 nh hng ca thi gian phn ng n chsacid .......................................... 38

Bng 8 Cc yu tcnh ............................................................................................. 39

Bng 9 nh hng ca lng xc tc H2SO4n chsacid ...................................... 40

Bng 10 Cc yu tcnh ........................................................................................... 41Bng 11 nh hng lng methanol n chsacid v hiu sut ca sn phm

biodiesel ......................................................................................................................... 42

Bng 12 Cc yu tcnh .......................................................................................... 43

Bng 13 nh hng nhit phn ng n chsacid v hiu sut ca sn phm

biodiesel ......................................................................................................................... 43

Bng 14 Cc yu tcnh ........................................................................................... 45

Bng 15 nh hng thi gian phn ng n chsacid v hiu sut ca sn phm

biodiesel ......................................................................................................................... 45

Bng 16 Cc yu tcnh nh hng lng KOH .................................................... 46

Bng 17 nh hng lng xc tc KOH n chsacid v hiu sut ca sn phm

biodiesel ......................................................................................................................... 47

Bng 18 Bng biodiesel chun theo QCVN 1: 2009/BKHCN ...................................... 49


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Sinh vin thc hin: Bi Lin Khoa vii

MC LC CC HNH V

Hnh 1 nh hng ca lng methanol n chsacid ............................................... 36

Hnh 2 nh hng ca nhit n chsacid ........................................................... 37

Hnh 3 nh hng ca thi gian phn ng n chsacid .......................................... 38

Hnh 4 nh hng ca lng xc tc H2SO4n chsacid ....................................... 40

Hnh 5 nh hng lng methanol n chsacid v hiu sut ca sn phm

biodiesel ......................................................................................................................... 42

Hnh 6 nh hng nhit phn ng n chsacid v hiu sut ca sn phm

biodiesel ......................................................................................................................... 44

Hnh 7 nh hng thi gian phn ng n chsacid v hiu sut ca sn phmbiodiesel ......................................................................................................................... 46

Hnh 8 nh hng lng xc tc KOH n chsacid v hiu sut ca sn phm

biodiesel ......................................................................................................................... 47

MC LC CC S

S 1 C chphn ng transester ha xc tc base ................................................... 18

S 2 C chphn ng ester ha ............................................................................... 20

S 3. Qui trnh tng hp biodiesel da trn phn ng transester ha c sdng xc

tc kim .......................................................................................................................... 21

S 4 Qui trnh hai bc tng hp biodiesel.............................................................. 29

CC CHVIT TT

ASTM: American Society for Testing and Materials

BKHCN: Bkhoa hc cng ngh

QCVN: Qui chun Vit Nam

RME: Rapeseed methyl ester

HFRR: High - frequency reciprocating rig


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Sinh vin thc hin: Bi Lin Khoa 1

CHNG 1

TNG QUAN TI LIU

-----oooOooo-----

I LIPID

I.1 Khi nim v lipid[1]

Tn gi Lipid xut pht tchHi Lp Lipos c ngha l cht bo. Lipid l

mt hp cht hu c c chc nng v thnh phn ha hc khc nhau c ly trch t

ng vt hay thc vt nh cc dung mi ether, chloroform, methanol, l mt trongnhng thnh phn sinh ha c bn ca ng thc vt. Cc thnh phn ca thc n

thng c tp trung nghin cu l protein, lipid, glucid v mt svitamine, trong

lipid ng vai tr quan trng nh l ngun cung cp nng lng v cc acid bo cn

thit cho qu trnh sinh trng v pht trin ca ng vt. Lipid cng ng vai tr nh

cht vn chuyn vitamine tan trong du v sterol.

Vo nm 1920, con ngi bit bnh do thiu vitamine c lin quan n ba n

thiu lipid nht l cc nhm vitamine tan trong du. Nhtnh dn nhit km ca lipid

nn n c xem l chic o bo vthn nhit.

Thnh phn chyu ca lipid trong hu ht cc loi du thc vt v mng vt

l triglyceride hay glyceride hoc mtrung tnh. Ngoi ra, cn c cc acid bo tdo,

phospholipid v sterol.

Triglyceride l mt ester ca glycerol v acid bo, c cng thc tng qut l:

H2C

HC

H2C

O

O

O

C

C

C

O

O

O

R1

R2

R3

Trong R1, R2, R3: l cc gc acid bo.

Cc acid bo trong phn tlipid l acid no hoc khng no.


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Cc acid no thng gp l:

CH3 (CH2)12 COOH (Acid lauric )

CH3 (CH2)14 COOH (Acid palmitic)

Cc acid bo khng no thng gp l:

CH3 (CH2)7 CH CH (CH2)7 COOH (Acid oleic)

CH3 (CH2)4 CH CH CH2 CH CH (CH2)7 COOH (Acid linoleic)

I.2 Phn loi v lipid[1] [2]

C nhiu kiu phn loi lipid. Hin nay c ba cch phn loi chnh:

I.2.1 Da vo phn ng x phng haDa vo phn ng x phng ha ngi ta chia lipid ra thnh hai loi:

Lipid x phng ha c: gm cc glyceride, glycerophospholipid v sp. Ngha

l nhng lipid m trong phn tc cha ester ca acid bo cao phn t.

Lipid khng x phng ha c: l nhng lipid m trong phn t khng cha

nhm ester. Nhm ny gm cc hydrocarbon, cc cht mu v cc sterol.

I.2.2 Da vo ha tanDa vo ha tan lipid c chia thnh hai loi nh sau:

Lipid thc s: l nhng ester hoc amide ca acid bo (c tbn carbon trln)

vi mt ru gm glycerolipid (ester ca glycerol), sphingolipid (amide ca

sphingozin), ceride (ester ca ru cao phn t), steride (ester ca sterol), etolite

(ester tng hca hp cht a chc acid v ru).

Lipoid: l nhng cht c ha tan ging lipid bao gm: carotenoid, quinon (ccdn xut ca isoprene), sterol tdo.

I.2.3 Da vo thnh phn cuto

Cch phn loi thba v lipid l da vo thnh phn cu to. cch phn loi ny

lipid chia lm hai loi nh sau:

Lipid n gin: trong phn t chcha C, H, O, l ester ca ru v acid bo.

Thuc nhm ny c: triacylglycerine, sp (ceride) v steride.


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Lipid phc tp: ngoi C, H, O cn c mt snguyn tkhc nh N, P, S, do

trong phn tca chng ngoi ru v acid bo, cn c cc thnh phn khc nh

acid phosphoric, ng Lipid t do c nhim v cung cp nng lng, hm

lng lun thay i nhng lipid phc tp li c nhim vtham gia xy dng cc

cu tca tbo, hm lng khng thay i hay rt t thay i.

Ngoi ra, cn cc lipid khc nh: terpene, steroid v prostaglandin

I.3 Chc nng ca lipid[1]

- Cung cp nng lng: lipid l ngun cung cp nng lng tt nht cho c

th ng vt. Lng calo do lipid cung cp cao gp 2 ln lng calo do glucid v

protid cung cp. Lipid l cht dtrnng lng cho c th. Mt gam lipid cung cp

9,3 calo trong khi mt gam glucid hay protid chcho 4,1 calo.

- Hot tnh v cu thnh enzyme v hormone.

- Tham gia cu trc mng tbo: lipid phn cc hay phospholipid c mt vai

tr rt quan trng trong dinh dng v n tham gia vo cu trc ca tt ccc mng t

bo.

- Htrhp thu cc lipid khc: phospholipid givai tr quan trng trong s

vn chuyn v hp thlipid v tham gia vo cc qu trnh bin dng trung gian trong

c thsinh vt. Phospholipid ng vai tr nh cht nh tng ha gip cc acid bo,

mui mt v cc cht ha tan trong cht bo gn vo cc ht micelle nhli ti.

- Vn chuyn cc vitamine v mt scht khc: lipid l dung mi ha tan cc

vitamine tan trong du nh A, D, E, K v hydrocarbon. Do , trong khi c hp thu

v vn chuyn trong c thlipid cng mang theo cc cht ha tan trong lipid.

- Chc nng bo v c th: lipid gip c th chng li cc va p c hc,

chng lnh v bo vcc c quan bn trong.

I.4 Tnh cht chung ca lipid[1] [3]

I.4.1 Tnh cht vt l

Lipid c t trng thp hn nc (0,86-0,97). Mc khng no trong mch

hydrocarbon cng ln th lipid c ttrng cng cao.


17/66



Lipid c c tnh chung l khng tan trong nc v tan trong cc dung mi hu

c nh: chloroform, benzene, ether.

Lipid khng tan trong nc, khi trn vi nc sto thnh hai lp: nc di

v cht bo trn, u -COO- tip xc vi nc, ui knc pha trn. Di tc

ng ca cht gy nh tng ha nh x phng (mui natri hay kali ca cc acid bo

bc cao hoc acid mt hay mui mt do gan tit ra) cht bo bchia nhra ging nh

dng sa gi l nh tng bn. Nhvy, x phng l cht ty ra du mtt chsau

cc dung mi hu c. iu cng gii thch c v sao cc bnh nhn bbnh gan

phi hn chn thc n c cha du mv trong c thca bnh nhn, du mtrong

thc n khng c nh tng ha, do lipase phn gii chm.

Tnh cht ca glyceride ph thuc vo thnh phn acid bo, chiu di mch

carbon v slng lin kt i trong phn t.

Mng vt cha nhiu acid bo no do trng thi bnh thng dng rn,

nht l mb, mcu. Du thc vt cng ty theo tlacid bo no v khng no m c

im nng chy khc nhau. V d du cacao cha 30% palmitic v 40% stearic c

im nng chy 30-40C. Ngc li du hng dng cha 85% acid bo khng no l

oleic v lenoleic nn c im nng chy rt thp (-21C). Do , du thc vt lun dng lng.

Nguyn nhn ca trng thi rn hay lng ca glyceride l do hm lng acid bo

no hay khng no v:

Cc acid bo no c mch carbon thng thng, khng gp khc to nn cu trc

n nh v cht, khng bph vnn nhit thng chng c trng thi rn.

Cc acid bo khng no c mch carbon bgp khc, to ssp xp lng lo db

ph v(do lc Van der Waals yu), do nhit thng chng trng thi

lng.

I.4.2 Tnh cht ha hc[3]

Phn ng thy phn v x phng ha

Vi shin din ca nc hoc hi nc v c xc tc ca enzyme lipase, du

mbthy phn sgii phng acid bo tdo v glycerol.


18/66



Phng trnh thy phn triglyceride c biu din nh sau:

H2C

HC

OCOR1

H2C

OCOR2

OCOR3

H2Oenzyme lipase, +

R1COOH

R2COOH

R3COOH

H2C

HC

OH

H2C

OH

OH

Glycerol Acid boTriglyceride

Nu c mt mt lng kim (KOH, NaOH) th sau phn ng thy phn, acid bo

tc dng vi kim to thnh mui kim (x phng).

RCOOH + NaOH RCOONa + H2O

Tng qut:

H2C

HC

OCOR1

H2C

OCOR2

OCOR3

Triglyceride

+ 3NaOH

H2C

HC

OH

H2C

OH

OH

Glycerol

R1COONa

R2COONa

R3COONa

X phng

+

Phn ng cng hydro

L phn ng cng hydro vo cc ni i trn mch carbon ca acid bo vi s

hin din ca cht xc tc thch hp. Phn ng ny c ng dng trong cng ngh

thc phm nhm lm gim sni i trn dy carbon v lm cho du mn nh hn,

hn chkhnng boxi ha, trng hp ca du m, gip cho du mkhng btrmi

khi bo qun lu.

C C + H2xt H

CHC


19/66



Phn ng vi ru

H2C

HC

OCOR1

H2C

OCOR2

OCOR3

+ 3ROH

H2C

HC

OH

H2C

OH

OH

R1COOR

R2COOR

R3COOR

+

y l phn ng c bn bin triglyceride thnh alkyl ester ca acid bo.

Phn ng oxi ha

Cc loi du mc cha nhiu acid bo khng no sdboxi ha. Phn ng

xy ra trn ni i ca mch carbon. Du mcha nhiu acid bo no dbo qun, t

bin i. Du mbo qun lu c thc cc hng chuyn ha sau: Phn ng thy phnc xc tc enzyme lipase sinh ra glycerol v cc acid bo.

Phn ng oxi hacc ni i ca acid khng no tng tnh phn ng oxi ha

cc olefin, sinh ra cc hp cht cha oxygen nh: aldehyde, ketone, alcohol,

Cc phn ng trn vi stham gia ca enzyme, oxygen trong khng kh, v nc

lm cho mc mi hi, gim cht lng. V vy, trnh hin tng ny, trong cng

nghthc phm ngi ta thng bao kn trnh du mtip xc vi oxygen ngoikhng kh, nh nng chiu vo (nu c ssinh nhit, phn ng thy phn mdin ra

nhanh hn) hoc c ththm cht chng oxy ha thng l phenol, quinon

II CC PHNG PHP THU LY DUBO TRONG B

C PH

II.1 Tch chit bng dung mi hu c[4]

Bdng csohxlet vi nhiu kch c. Phng php ny c u im chsdng

mt lng t dung mi m c thchit kit c hot cht. Sly trch tng, lin

tc nn nhanh chng. Dng dung mi knc trch ly hon ton lipid tnguyn liu

c nghin nh. Mt s thnh phn ha tan trong cht bo cng c trch ly

theo bao gm sc t, cc vitamin tan trong cht bo, cc cht mi... tuy nhin hm

lng ca chng khng cao.

Nhc im ca phng php ny l khng chit c mt lng ln mu, nn

chthch hp cho cc nghin cu trong phng th nghim. Mt nhc im ln na l


20/66



trong sut qu trnh chit, mu lun c nhit bng nhit si ca dung mi nn

nhng hp cht km bn nhit c thbthy gii.

Ta c th dng phng php tch chit khc nh: phng php ngm dm,

phng php ngm kit ngc dng chit vi lng mu ln.

II.2 Tch chit bng CO2lng siu ti hn[5]

Thay v sdng cc dung mi hu c, ngi ta c thsdng CO2trng thi

siu ti hn (31,1C, 73 atm). t bit trng thi ny CO2va ging nh kh, va

ging nh lng, c nht thp hn pha lng (dxm nhp vo mu), c khnng

chuyn khi ln hn pha kh (chit xut c cn kit hot cht). Vi trng thi pha

lng ny n sl iu kin l tng trch cu ttrong mt thi gian ngn. Bng

cch kim sot nhit v p sut, mt v tc dung mi, CO2lng ti hn c th

thay thcc dung mi hu c (CHCl3, diethyl ether, petro ether, n-hexane). Nhkh

nng ha tan m ta c thvn dng chng vo vic tinh ch, trch ly, ngm chit, kt

tinh Nhit cao lm tng ng hc chit, trong khi p sut cao sgi cho dung

mi thot khi sun si. So snh vi phng php trch Shoxlet th r rng phng

php ny c nhiu mt tin li hn nhiu nh tit kim thi gian hn, chi ph dung mi

gim r, gim cht thi tdung mi. Tuy nhin vn ln nht gp phi l cn chi phln cho thit b, dng c, my mc.

II.3 Tch chitbng enzyme[6]

Vic tch chit du bo bng enzym c nhiu nh nghin cu quan tm

ng thi t c thnh cng nht nh. Chit xut du c ph bng enzyme cha

c nghin cu nhng chit sut du da bng enzyme cytolase c Vin

Nghin cu Du Thc vt- Tinh du- Hng liu- Mphm (Bcng nghip) kho

st v chit sut thnh cng du tinh khit, du c chit xut tenzyme cylolate c

cht lng cao, do c phm vi ng dng rng ri hn du da c sn xut bng

ccphng phpcng nghip cin.

II.4 p bng my[7]

Phng php p tuy n gin nhng khng trit , hm lng du ca b p cn

4-5%; i vi nguyn liu t du th hiu qukinh tthp. Trong cng nghip p du,

chc nhng loi ht c hm lng du t15-20% trln mi c gi trthc ttchc sn xut v m bo c cc hiu qukinh tkthut trong khi sn xut.


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III BIODIESEL

III.1 Nhin liu diesel

Nhin liu diesel l phn hydrocarbon ly t du m ra, c nhit si nm

trong gii hn t200 n 300C. Du diesel c mu nu nht, nng hn xng, nhhn

nc, ttrng t0,80 n 0,86[8].

Nhin liu diesel rtin hn xng nn c sdng rt rng ri trong cc ngnh

cng nghip. ng c diesel c dng nhiu xe vn ti nng, xe tng, tu thy, tu

ha, my pht in cln v.v

III.2 S lc v biodiesel

III.2.1 Khi nim

Biodiesel hay cn gi l diesel sinh hc, l mt loi nhin liu c tnh cht tng

tdiesel c ngun gc tdu mnhng c sn xut tdu thc vt hay mng

vt. Biodiesel c thnh phn chnh bao gm cc mono-alkyl ester ca chui cc acid

bo c ngun gc tthc vt hay mng vt[8].

Mono-alkyl ester l sn phm ca phn ng gia alcol mch thng (nh methanol

hoc ethanol) vi mng vt hoc du thc vt to thnh glycerol v ester ca acidbo mch di.

H2C

HC

OCOR1

H2C

OCOR2

OCOR3

+ CH3OH

H2C

HC

OH

H2C

OH

OH

R1COOCH3

R2COOCH3

R3COOCH3

+3

Triglyceride Methanol Glycerol Biodiesel

Ty thuc vo loi du thc vt v loi ru sdng m alkyl ester c tn khc

nhau.

Nu i t du cy u nnh (soybean) v methanol th ta thu c SME (soy

methyl esters). y l loi ester thng dng nht c sdng ti M.


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Nu i tdu cy ci du (rapeseed) v methanol th ta thu c RME (rapeseed

methyl esters). y l loi ester thng dng nht c sdng Chu u[9].

Biodiesel ph hp vi ng c diesel, cvnht, khi lng ring ln chs

cetane v n ging vi diesel du m. Bng 1 cho cc thng sso snh gia biodieselv diesel du m[10].

Bng 1So snh mts ch tiu gia biodiesel (RME) v diesel

Tnh cht nhin liu Biodiesel RME Diesel

Cng thc ha hc

Trng lng phn t

Chscetane

Khi lng ring (Kg/l) 15C

Trgi calo (MJ/Kg) 15C

Trgi calo (MJ/l) 15C

Tlkhng kh/ nhin liu (kg

khng kh/ kg nhin liu)

Hm lng oxy (Wt%)

nht (mm2/ giy) 20C

im chy (C)

Methyl ester

296

54

0,88

37,3

32,8

32,8 (20C)

9,211

7,4

91135

C12H26

170200

50

0,84

42,7

35,7

14,53

00,6

4

77

Biodiesel c thsdng trong cc ng c diesel thng thng dng nguyn

cht (100% biodiesel B100), hoc dng pha trn k hiu l BXX, trong XX l

phn trm biodiesel cn pha. Biodiesel thng c pha chvi du diesel to ra

cc loi nhin liu sau y:

- B5 gm 5% biodiesel pha vi 95% du diesel.

- B10 gm 10% biodiesel pha vi 90% du diesel.

- V B20 gm 20% biodiesel pha vi 80% du diesel.


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Biodiesel t c, khng gy nhim mi trng v l mt loi nng lng ti

to. Do mc d gi thnh cao hn so vi nhin liu diesel nhng biodiesel c

xem l ngun nng lng cho tng lai.

III.2.2 Lch shnh thnh v pht trin ca biodiesel

[9]

Biodiesel bt u c sn xut khong gia nm 1800, trong thi im

ngi ta chuyn ha du thc vt thu glycerol v thu c cc phphm l methyl

hoc ethyl ester gi chung l biodiesel. Ngy 10/08/1893, ln u tin Rudolf Diesel

sdng biodiesel do ng chto chy my. Nm 1912, ng dbo:Hin

nay, vic dng du thc vt cho nhin liu ng c c thkhng quan trng, nhng

trong tng lai, nhng loi du nh thchc chn sc gi trkhng thua g cc sn

phm nhin liu tdu mv than . tng nhngi c cng u tin on

c gi tr to ln ca biodiesel, t chc Nation Board Biodiesel quyt nh ly

ngy 10 thng 8 hng nm bt u t nm 2002 lm ngy Diesel sinh hc Quc t

(Internation Biodiesel Day). Trong nhng nm ca thp k90, Php trin khai sn

xut biodiesel tdu ht ci v c dng dng B5 (5% biodiesel vi 95% diesel) v

B30 (30% biodiesel trn vi 70% diesel).

III.2.3 Tnh hnh sdng biodiesel trn thgii v Vit Nam[9]

Theo xu hng chung trn thgii, ngi ta thng trn biodiesel vo diesel vi

thnh phn phi trn t5-30%. chu u theo chth2003/30/EC ca EU tngy 31

thng 12 nm 2005 t nht l 2% v cho n 31 thng 12 nm 2010 t nh t l 5,75%

thnh phn ca cc nhin liu dng chuyn chphi c ngun gc ti to.

Ti o, mt phn ca chthEU c thc hin sm hn v tngy 1 thng

11 nm 2005 chcn c du diesel cha 5% c ngun gc sinh hc (B5) l cphp bn.

Ti Australia, sdng B20 v B50 vo thng 2 nm 2005.

Ti Mnm 2005 sdng B20.

Ti Thi Lan trong nm 2006, sdng B5 ti Chiangmai v Bangkok.

Ti Vit Nam, Petro Vit Nam c k hoch a 10% Biodiesel (B10) vo

thnh phn diesel lu thng trn thtrng.


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III.3 Cc ch tiu ha l ca biodiesel[11]

Cht lng biodiesel c nh gi qua mt schtiu nh: chsacid, nht,

pH, tro sulfate, lu hunh, trscetane, glycerol tdo, glycerol tng, hm lng tro

phospho, mc bay hi, khi lng ring v hm lng nc cha trong nguyn

liu.

III.3.1 nht

nht ca nguyn liu th hin s lu chuyn nhin liu d dng trong h

thng cung cp v np liu vo bung t ca ng c. y l mt trong hng chtiu

quan trng ca nhin liu. Ngi ta dng my chuyn dng o nht.

nht cao: tnh lu chuyn hn ch, nhin liu kh vn chuyn v np liu vo

bung t.

nht thp: gim hsnp liu v tng smi mn ca bm nhin liu.

III.3.2 ChspH

ChspH ca nhin liu tt nht xp x7 v nu pH cao hay thp hn 7 u nh

hng n mc n mn thit b.

III.3.3 Tro sulfate

Cht lng tro c thtn ti trong diesel sinh hc gc di ba dng: (1) cc cht

rn c tnh mi mn, (2) x phng kim loi tan c v (3) cc cht xc tc khng loi

bc. Cc cht rn c tnh mi mn v cc cht xc tc khng loi bc sng

li vi phun, bm nhin liu, piston v ai bo v, ng thi cng to cn trong ng

c. X phng kim loi tan c c tnh n mn t, nhng li lm tt blc v to cn

trong ng c.III.3.4 Lu hunh

nh hng ca hm lng lu hunh rt khc nhau i vi sn mn ng c

v to cn lng. iu ny ph thuc nhiu vo cc iu kin vn hnh. Lu hunh

trong nhin liu cn nh hng n tnh nng ca h thng kim sot kh pht thi.

B100 l loi nhin liu hu nh khng c lu hunh.


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III.3.5 Trscetane

Trscetane l i lng thhin khnng bc chy ca nhin liu, nh hng

schy v to khi trng. Yu cu vtrscetane phthuc vo thit k, kch cca

ng c, bn cht thay i v tc v ti trng v ph thuc vo iu kin mi

trng v iu kin khi ng.

III.3.6 Chsacid

L smg KOH cn thit trung ha ht lng acid bo tdo trong 1g cht bo.

Ch s acid l mt trong nhng ch tiu quan trng nh gi cht lng

nguyn liu. Tchsny, chng ta c thxc nh c hm lng acid tdo hin

din trong mu nguyn liu. Biodiesel cng cha nhiu acid bo tdo th c ch sacid cng cao. Chsacid thay i theo thi gian lu tr. Thi gian tn trcng di

th ch sacid cng tng v xy ra phng thy phn gii phng cc acid t do v

glycerol. Sthy phn ny xy ra khi mch carbon ca triglyceride ngn hoc di tc

dng ca enzyme lipase.

III.3.7 Glycerol tdo

p dng phng php xc nh glycerol tdo xc nh mc glycerol c trongnhin liu. Cc mc glycerol tdo cao c th to cn cho vi phun nhin liu, cng

nh lm tt hthng nhin liu v dn n stch ly glycerol tdo di y hthng

tn cha v cp nhin liu.

III.3.8 Glycerol tng

p dng phng php glycerin tng xc nh mc glycerin c trong nhin liu

bao gm cglycerin tdo v phn glycerin ca du hoc mkhng phn ng hoc

phn ng mt phn. Cc mc thp ca glycerin tng m bo du hoc mchuyn i

thnh ester mono-alkyl tt. Cc thnh phn mono-, di- v triglyceride c thgy cn

vi phun v tc ng xu khi vn hnh ng c kh hu lnh v lm tt blc.

III.3.9 Hm lng tro phosphorus

Phosphorus c thlm hng bchuyn i xc tc sdng trong hthng kim

sot kh thi v phi gii hn hm lng phosphorus thp. Bchuyn i xc tc tr

thnh phbin i vi thit bchy bng diesel do tiu chun kh pht thi btht cht,


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v vy mc phosphorus thp cng trnn quan trng. Ch tiu ny c qui nh

m bo tt ccc loi diesel sinh hc gc chbin tcc ngun du, mu phi c

hm lng phosphorus thp.

III.3.10 Hm lng nc ln vo nhin liuCn trnh ln nc vo nhin liu v nc cng l yu t gy bin cht nhin

liu, tng phn ng oxy ha, gim nhit t chy trong ng c.

C nhiu phng php lm kh loi nc hoc dung mi ra khi sn phm

hay nguyn liu ban u. Ty theo bn cht ca sn phm hay nguyn liu ban u m

ta c thsdng mt sphng php phbin sau:

-

Chng ct: da vo s chnh lch nhit si ca cc cht thu c snphm tinh khit.

- Dng ha cht: yu cu ha cht khng tc dng vi nguyn liu, c khnng

ht nc mnh, khng ha tan trong nguyn liu, c tc dng lm kh nhanh, r

tin v phbin.

Sy chn khng: l phng php gia nhit trong mi trng chn khng.

III.4 Nhng u, nhc im ca biodiesel[12]III.4.1 Nhng u im khi s dng biodiesel cho ng c diesel

III.4.1.1 V mt mi trng

Qui trnh sn xut khng c cht thi v tt ccc sn phm phu c thtip

tc sdng.

Trong biodiesel hm lng lu hunh rt thp, khong 0,001%. Hm lng cc

hp cht khc trong kh thi nh: CO, SOx, hydrocarbon cha chy, bhng gim i

ng k, cth:

Gim ng kkh thi CO2gy hiu ng nh knh v sc khe con ngi.

Gim kh thi SOxgy nhim mi trng.

Khng cha hydrocarbon thm nn khng gy ung th. Theo cc nghiu cu

ca B Nng lng M c thc hin ti trng i hc Califonia, s dng

biodiesel tinh khit thay cho diesel khong c thgim 93,6% nguy c mc bnh ungthtkh thi ca ng c, do biodiesel c cha t cc hp cht thm, cha rt t lu


27/66



hunh, qu trnh chy ca biodiesel trit hn nn gim c nhiu thnh phn

hydrocarbon trong kh thi.

C khnng tphn hy v khng c (phn hy nhanh hn gp 4 ln diesel

khong, phn hy t85 88% trong nc sau 2128 ngy). Tuy nhin, sthun li

ny yu cu sch c bit vqu trnh bo qun nhin liu.

Gim nhim mi trng v nc.

Gim s tiu dng ca cc sn phm du m gy nhim mi trng trm

trng.

III.4.1.2 V mt k thut

c tnh t lu hunh ca biodiesel lm gim ng kkh thi SOxgy n mn

thit b. Chnh nhng cht cha lu hunh l nhng tc nhn gim ma st ca du

diesel khong, do vy du diesel khong c tnh bi trn khng tt v i hi vic s

dng thm cc phgia tng tnhbi trn.

Chscetane cao hn diesel khong: nhin liu diesel thng thng c chs

cetane t50-52 v 53-54 i vi ng c cao tc. Biodiesel l alkyl ester mch thng

do vy nhin liu ny c ch s cetane cao hn diesel khong. Ch s cetane ca

biodiesel thng t56-58. Vi chscetane nh vy, biodiesel hon ton c thp

ng ddng yu cu ca ng c i hi nhin liu cht lng cao vi khnng tbt

chy cao m khng cn phgia tng chscetane.

An ton vchy n tt hn: biodiesel c nhit chp chy cao hn 110C,

cao hn nhiu so vi diesel khong (khong 60C), v vy tnh cht nguy him ca n

thp hn, an ton hn trong tn cha v vn chuyn.

Qu trnh chy sch: do nhin liu biodiesel cha khong 11% oxy nn qu

trnh chy ca nhin liu xy ra hon ton. V vy vi nhng ng c sdng nhin

liu biodiesel th sto mui, ng cn trong ng c gim ng k.

Tnh linh ng ca biodiesel: c thtrn vi diesel theo bt ktlno.

Biodiesel c tnh bi trn tt: biodiesel c khnng bi trn bn trong rt tt.

Cc cuc kim tra chra rng, biodiesel c khnng bi trn tt hn diesel khong.

Khnng bi trn ca nhin liu c c trng bi gi trHFRR (High-frequency


28/66



recieprocating rig). Ni chung gi trHFRR cng thp th khnng bi trn ca nhin

liu cng tt. Diesel khong x l lu hunh c gi trHFRR ln hn hoc bng

500 khi khng c phgia, nhng gii hn c trng ca diesel l 450. V vy, diesel

khong yu cu phi c phgia tng khnngbi trn. Ngc li gi trHFRR ca

biodiesel khong 200. V vy, biodiesel cn nh l mt phgia rt tt i vi nhin

liu diesel thng thng. Khi thm biodiesel vo vi t lthch hp, smi mn ca

ng c c gim mnh. Thc nghim c chng minh sau khong 15.000 gilm

vic, smi mn vn khng c nhn thy.

Do c tnh nng tng t nh du diesel khong nn nhn chung khi s dng

khng cn ci thin bt kchi tit no ca ng c.

i tng sdng: Tt ccc loi ng c, my mc cngnghip sdng nhin

liu diesel.

III.4.2 Nhc im ca biodiesel

Dboxy ha nn snh hng n mt sbphn trong ng c.

Biodiesel dht m.

Biodiesel c nht cao, vic phn tn nhin liu kh mn, khng u nn gy

kh khn cho qu trnhphun nhin liu vo t.

Nhit trnhhn diesel nn trn cng mt qung ng di chuyn cn hao tn

lng nhin liu nhiu hn.

Gi thnh vn cn kh cao hn diesel. Tuy nhin theo tnh hnh bin ng du

mhin nay th vic tm ra mt ngun nhin liu mi srt c gi tr.

III.5 Cc phng php ha hc s dng trong tng hp biodiesel

[2][13][14]

III.5.1 Phn ng transester ha lipid

Qu trnh transester ha du bo thc vt v m ng vt c tin hnh vo

nm 1853 bi hai nh khoa hc E.duffy v J.Patrick.

Transester ha l phn ng gia mono-, di-, triglyceride vi ru cng vi s

hin din ca cht xc tc thch hp, to thnh cc alkyl ester ca cc acid bo v

glycerol.


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III.5.1.1 Cc phng php thc hin phn ng transester ha lipid

Phn ng transester ha thng c tin hnh bng nhng phng php sau

y:

Phng php khuygia nhit

y l phng php c in. Ngi ta s dng my khuy c hc hay my

khuy tc gia nhit khuy trn hn hp to nn stip xc tt gia hai pha ng

thi cung cp nhit cho qu trnh phn ng. Phng php ny dthc hin, c tht

c phn ng hon ton nhng i hi thi gian kh di.

Phng php siu m

Trong nhng nghin cu gn y, phng php siu m thng c p dngcho phn ng transeter ha v c u im l rt ngn thi gian phn ng, ng thi

phn ng t c chuyn ha cao.

Phng php vi sng

Vi sng cn c tn gi l sng vi ba (microwave) l sng in tlan truyn vi

vn tc nh sng, c bc sng trong khong t1cm (tn s30 GHz) n 1m (tn s

300MHz). Theo nguyn l hot ng ca sng vi ba, tt cnng lng sng thay it cc dng sang cc m trong mi chu k sng. Tc ca s thay i kh ln,

hng triu ln/giy. Cc phn tca cc cht, c bit l cc phn t lng cc, c

mt cc dng v mt cc m. Khi cc sng vi ba chiu x, chng to ra cc phn t

chuyn ng hn n, schuyn ng c thhng triu ln/giy. Chnh srung ng

ca cc phn tny to nn ma st lm nng cc cht.

III.5.1.2 Xc tc s dng trong phn ng transester ha

Cc cht xc tc s dng trong phn ng transester ha c th l acid, base,

enzyme hay zeolite.

Xc tc acid

Xc tc acid thng sdng trong phn ng transester ha l H2SO4m c.

Tuy hiu sut phn ng cao nhng phn ng li xy ra chm, i hi nhit trn

100C v 4 gimi t chuyn ha hon ton. Ngoi ra, phn ng trn phi c

thc hin trong mi trng khng c nc trnh c s cnh tranh to ra acid

carboxylic lm gim hiu sut phn ng. Thit bphn ng mau h do bn mn.


30/66



Xc tc base

Phn ng transester ha du m ng thc vt s dng xc tc base din ra

nhanh, ng thi xc tc base t n mn thit bnn xc tc base rt c a chung

trong cng nghip.

Xc tc base thng c s dng trong cng nghip nh: NaOH, KOH,

carbonate kim loi kim, CH3ONa,... Tt ccc loi xc tc ny u c ththu c

ester cht lng cao. Nhng ty thuc vo cng sut ca cc nh my v nhng iu

kin cthkhc m ngi ta dng loi xc tc ny hoc xc tc khc.

dng thnh phm, NaOH v KOH u dng rn. to ra tc nhn xc tc

phn ng l CH3O-, ngi ta phi ha tan chng vo trong ru CH3OH trc khi cho

vo hn hp phn ng. Qu trnh ha tan ny ta nhit v rt nguy him v bn thn

CH3OH v kim rt c. Nh vy, nhng nh my sdng KOH, NaOH phi tn

thm chi ph cho khu chun bcht xc tc cng nh cc bin php xl an ton. Do

vy, Chu u v Mngi ta dng NaOH, KOH nhng nh my c cng sut nh

hn 5 triu galng.

Thm vo khi ha tan NaOH, KOH vi CH3OH, nc sinh ra theo phn ng:

NaOH + CH3OH CH3ONa + H2O

Nc gy thy phn triglyceride v ester to thnh, lm gim hiu sut ca phn

ng ng thi gy kh khn thm cho qu trnh loi bnc sau ny. KOH t hn

NaOH nhng KOH c li l tan rt tt trong CH3OH. Khc vi NaOH v KOH,

CH3ONa tan hon ton v khng sinh ra nc. CH3ONa thng dng dng ha tan

(25-30%) trong CH3OH do sn sng cho phn ng, khng mt thm chi ph cho

vic chun bcht xc tc. Khi sdng cht xc tc ny, hiu sut thu methyl ester l

cao nht trong khi tn t cht xc tc hn so vi trng hp NaOH v KOH. Thm vo

, glycerol thu c l tinh khit hn dn n lm gim chi ph cho qu trnh lm

sch glycerol khi mun iu chsn phm khc tglycerol.

Mc d CH3ONa c gi thnh cao (gp 2 ln KOH), nhng nhng li ch ca n

c thb li trong trng hp cng sut nh my ln (>5 triu galng).


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Trn thc t, 2/3 nh my sn sut methyl ester (biodiesel) cng sut ln Chu

u v 70% methyl ester sn xut ti Bc M s dng loi xc tc ny. Phn ng

transester ha du thc vt, mng vt sdng xc tc base c biu din nh sau:

H2C

HC

OCOR1

H2C

OCOR2

OCOR3

+ ROH

H2C

HC

OH

H2C

OH

OH

R1COOR

R2COOR

R3COOR

+3 KOH

Trong : R1, R2, R3l cc gc acid bo.

C chphn ng transester ha:

ROH + B + BH

R1COO CH2

CHR2COO

H2C

O

+

R1COO CH2

CHR2COO

H2C O C

OR

O

R3

(2)

(1)

R1COO CH2

CHR2COO

H2C O C

OR

O

R3

R1COO CH2

CHR2COO

H2C O

+ RCOOCR3 (3)

R1COO CH

2

CHR2COO

H2C O

+ BH

R1COO CH2

CHR2COO

H2C OH

+ B (4)

RO

OR

OCR3

S 1 C chphn ng tr ansester ha xc tc base

Xc tc enzyme

a scc enzyme lm xc tc u c thc hin iu kin bnh thng (nhitphn ng l 20-40C), khng tn nng lng v khng i hi thit bphc tp,


32/66



hiu lc xc tc ln. Tuy nhin mi loi enzyme chxc tc mt scht nn v kiu

ni ha hc nht nh trong phn t. Ngoi ra, vic sdng xc tc enzyme c mt

hn ch l thi gian phn ng rt lu (20 gi), ng thi phi tm c loi enzyme

ph hp vi i tng nghin cu.

Xc tc zeol i te

Trong nhng nm gn y, ngi ta thng sdng xc tc acid, base rn, c

bit l zeolite. y l l loi xc tc hiu qu cho phn ng transester ha du m

ng, thc vt do c tnh chn lc cao, vic tch cc sn phm sau phn ng ddng,

hiu sut cao ng thi phn ng t sinh ra sn phm ph.

III.5.2 Phn ng ester ha acid carboxylic

Ester ha acid carboxylic l qu trnh tch nc gia acid v ru to thnh

ester.

Phn ng ester ha c tnh thun nghch, chiu thun c xc tc bng acid

mnh nh H2SO4m c, cn phn ng thy phn (chiu nghch) c thxc tc bng

acid hay base (trng hp thy phn bng base cn c gi l phn ng x phng

ha).

Phn ng ester ha cc acid carboxylic c th tin hnh khng cn xc tc, tuynhin n xy ra tng i chm v t c vn tc tng i cn nhit cao

(200-300C).

Phng trnhphn ng ester ha c biu din nh sau:

R1COOH+ ROH R1COOR + H2OH

C chphn ng ester ha c trnh by trong s sau:


33/66



RC

O

OH + H RC

OH

OH

RC

OH

OH + CH3OH RC OH

OH

RC OH2

OCH3

OH

RC OH2

OCH3

OH

RC

OH

OCH3 + H2O

RC

OH

OCH3 RC

O

OCH3 + H

HOCH3+

RC OH

OH

HOCH3+

S 2 C ch phn ng ester ha


34/66



III.6 Tng hp biodiesel da trn phn ng transester ha c s dngxc tc kim[15]

Trong cng nghip, biodiesel c sn xut nh trong s sau:

S 3 Qui trnh tng hp biodiesel da trn phn ng transester ha c s dngxc tc kim

III.6.1 i vi duthc vt hoc m ng vtc hm lng acid t do thp

Du nguyn liu, ru, v cht xc tc c trn trong l phn ng trong thi

gian thch hp (1-2 gi) nhit khong 60C. Qu trnh thu biodiesel c thlin

tc hoc theo chu k. Trn thc tqu trnh c thc hin lin tc qua hai giai on

(2 l phn ng), khong 80% lng ru v xc tc c dng l thnht, hn hp

phn ng sau khi tch khi pha glycerol c a vo l thhai kt thc phn ng

vi lng ru v xc tc cn li.

Glycerol to thnh c tch khi pha ester my li tm. Qu trnh tch thng

xy ra ddng v glycerol hu nh khng tan trong ester. Lng ru d c thlm

chm qu trnh tch v ru ha tan tt cglyxerol ln ester. Nhng khng thui

H2O

Lm kh

Ranc

H2O

CH3OH

LPhnng

Acid

Tch CH3OHGlycerol Chng ct

Phaester

PhaGlycerol

Biodiesel

Acid

- Trung ha- Loi CH3OH

CH3OH

Acid bo tdo

Du thc vt hocmng vt

Tch

Acid ha v tchacid bo tdo

Ncra

Xc tc kim


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lng ru d trc qu trnh tch pha v nh thsdch chuyn cn bng vpha to

ra glycerol.

Ester sau khi tch khi glycerol c a n khu trung ha v qua thp tch

methanol. khu trung ha ngi ta dng acid nh HCl, acid nitric trung ha

lng xc tc kim d v lng x phng to thnh:

RCOOK + HA RCOOH + KA

KOH + HA KA + H2O

Tt clng xc tc d, x phng, mui, methanol v glycerol tdo c tch

khi biodiesel bng qu trnh ra nc. Trung ha bng acid trc khi ra nc nhm

gim ti a lng x phng v lng nc ra cn dng do hn chc qu trnh

to nh tng (nc trong biodiesel v tc nhn to nh tng l x phng), gy kh

khn cho vic tch nc khi biodiesel. Biodiesel c lm sch trong thp bay hi.

Nu sn xut qui m nhngi ta thng dng cc mui kh ht nc. Mt s

ngun nguyn liu cha mt lng ln acid bo tdo. Acid bo tdo phn ng vi

xc tc kim sinh ra x phng v nc. Thc tcho thy rng qu trnh thu biodiesel

c thxy ra bnh thng vi hm lng acid tdo thp hn 5%. Khi , cn dng

thm xc tc trung ha acid bo tdo. Lng x phng to ra nm mc cho php.

III.6.2 i vi du thc vt hoc m ng vt c hm lng acid bo t do cao

Khi hm lng acid tdo cao hn 5%, lng x phng to ra lm chm qu trnh

tch pha ester v glycerol, ng thi tng mnh sto nh tng trong qu trnh ra

vi nc. gim hm lng acid bo tdo, trc phn ng chuyn vester, ngi ta

dng xc tc acid nh H2SO4, chuyn ha acid bo tdo thnh ester (phn ng ester

ha).

H2SO4RCOOH + CH3OH RCOOCH3 + H2O

V vy, hm lng acid bo tdo l yu tchnh trong vic la chn cng ngh

cho qu trnh sn xut biodiesel.


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III.7 Tim nng sn xut biodiesel t b c ph[16]

Theo hip hi C ph Vit Nam (VICOFA) v BNng nghip M (USDA),

tiu thc ph thtrng ni a Vit Nam nin v2010 sn mc 72 nghn tn

ht (chim 6,7% tng sn lng c ph sn xut ra). Nu qu trnh thu du mc 6,4

kg b c ph (t8,53 kg ht xanh do qu trnh rang hao ht 20-25%) sn xut c 1

lt biodiesel th ton blng b c ph thi ra nm 2010 scung cp thm cho ngnh

nng lng Vit Nam khong 6.921 tn biodiesl.

Vit Nam quan tm n ngun nhin liu biodiesel cch y 20 nm v

n pht trin ngnh nhin liu sinh hc n nm 2015, tm nhn n nm 2025 c

Th tng Chnh phph uyt ngy 20/11/2007. V tim nng c nhiu ngun

nguyn liu sn xut biodiesel bit nh:

1.Du mphthi qua sdng: gm cc phphm du mi tcc nh my

chbin du m, du m qua sdng, c thu hi sau qu trnh rn, nu tcc c

schbin thc n.

2. Vi to l gii php c thgii quyt vn din tch t trng v n c chu k

pht trin rt ngn, sng c khp ni c nh sng mt tri, nc v CO2.

3. Rng, ngcc, vng, lc, da, mc basa

4.Cy Jatropha c ngun gc tTrung M, di thc sang Chu Phi, n v

Nam M, cy chu hn, trng t kh cn v c nhiu loi. Nc ta c thtn dng 9

triu ha t hoang ha, dc ven cc ng quc l, trng cy Jatropha ly du.

B c ph phthi cng c khnng l tim nng mi, tn dng ngun nguyn

liu sn c, tit kim ti nguyn v gp phn bo vmi trng.


37/66



CHNG 2

PHNG TIN V PHNG PHP NGHIN CU

-----oooOooo-----

I NI DUNG NGHIN CU

Mc tiu nghin cu ca ti ny l nghin cu xy dng quy trnh tng hp

du diesel sinh hc (biodiesel) tb c ph phthi.

t c mc tiu nghin cu trn, hai ni dung nghin cu chnh ca ti

nh sau:

- Nghin cu phng php trch ly du bo tb c ph.

- Nghin cu quy trnh tng hp biodiesel tdu bo trch ly tb c ph.

II PHNG TIN NGHIN CU

II.1 Thit b v dng c

- Bchit soxhlet thtch 400ml

- Hthng un hon lu

- My c quay chn khng (BuchiThy S)

- My khuy tgia nhit IKA RCT

- Cn phn tch GF-Series AND model GF-300

- Tsy Memmertc

-

Cc dng cthy tinh: Phu chit, buret, nhit k, bnh c quay, bnh nh mc,

bnh tam gic, bnh cu c nhm, cc thy tinh cc loi, ng ht, pipet, ng

ong, ng nghim,

II.2 Ha cht

- Dung mi petroleum ether (PE)

- Acid sulfuric (H2SO4) m c

- KOH khan


38/66



- Methanol (CH3OH)

- Ethanol (C2H5OH)

- Nc ct

-

Sodium sulfate khan (Na2SO4)

- Phenolphthalein

II.3 Nguyn liu

Ngun b c ph c thu cc qun c ph khc nhau, trong qun c ph

Happy4 ng 91B thnh phCn Th l chim slng ln nht. B c ph c

thu ly, phi ngoi nng n kh. Sau tin hnh chit ly du bo v thc hin phn

ng.

III PHNG PHP NGHIN CU

III.1 Phng php ly trch du bo t b c ph

III.1.1 Phng phpchitSoxhlet

Dng dung mi petroleum ether ly trch du bo t b c ph. Cn 200 g

nguyn liu dng bt cho vo ti vi, t vo bnh trch soxhlet. Cho vo bnh cu 700

mL dung mi, lp vo bdng csoxhlet. un hon lu petroleum ether ly trch

du bo trong 5 gin khi dung mi trong bnh chit soxhlet khng cn mu ca vt

du. Ginguyn dung mi nhng thay 200 gnguyn liu mi v tip tc ly trch du

bo. Sau lc li dung mi cha du bo, c quay thu hi dung mi di p sut

km, cn lng du bo thu c. Lp li th nghim 3 ln vi mi mu.

III.1.2 Phng php ngm dm

B c ph kh (m khong 6,36%) c ngm vi dung mi petroleum ether

trong10 ngy theo tl: 1 kg b/ 3 lt dung mi.

Lc, c quay thu hi dung mi di p sut km.


39/66



III.2 Xc nh cc ch s ha l ca dubo trch ly t b c ph phthi

III.2.1 Xc nh m b c ph v hm lng cht bay hi

III.2.1.1 Nguyn tc

Nguyn tc ca phng php ny l da trn sgim khi lng ca mu b cph sau khi sy trong t sy nhit 100-105C n khi lng khng thay i.

Lng cht bc i nhit ny chyu l nc, ngoi ra cn c mt scht hu c

dbc hi.

III.2.1.2 Tin hnh

Chun b3 mu, cn mi mu chnh xc 5g bt nguyn liu, sy 105C trong

2 gi, ly ra cn, tip tc sy n khi lng mu vn khng i. Lp li th nghim 3

ln. Ly kt qutrung bnh ca 3 ln o.

III.2.1.3 Tnh kt qu

1001

m

mmN

%

Trong : m l khi lng mu cn ban u (5g)

1m l khi lng sau sy kh 105C trong 2 gi(g)

N l m ca b c ph (%)

III.2.2 Ch sacid (IA)

III.2.2.1 ngha

Chsacid l smg KOH cn thit trung ha lng acid bo tdo c trong

1g cht bo.

III.2.2.2 Nguyn tc

Dng KOH trung ha lng acid bo tdo c trong cht bo, phn ng xy ra

RCOOH + KOH RCOOK + H2O

III.2.2.3 Tin hnh

- Cn chnh xc 0,13gam cht bo cho vo erlen 100 mL.

- Thm 5 mL ethanol tuyt i.

-

Thm 2 git phenolphthalein.


40/66



- Lc nhha tan cht bo.

- Chun bng cch nh t t dung dch KOH 0,01N tburet vo erlen

trung ha acid tdo c trong cht bo cho n khi va xut hin mu hng nht v bn

trong 30 giy.

III.2.2.4 Tnh kt qu

Chsacid ca du mc tnh theo cng thc sau:

m

VIA

561,0

Trong :

V

: thtch dung dnh KOH 0,01N dng chun (mL).m : khi lng mu cht bo (gam).

III.3 Tng hp biodieesel t du bo ca b c ph ph thi

C nhiu cch lm gim chsacid ca du nguyn liu tnh cht ca n gn

ging vi tnh cht ca diesel truyn thng. Trong ti ny, chng ti s dng

phng php transester ha v y l phng php khng phc tp, c ththc hin

qui m nhv to ra sn phm c tnh cht ha l gn ging vi diesel truyn thng.Vmt k thut c nhiu phng php thc hin phn ng transester ha.

Trong ti ny chng ti sdng phng php khuy gia nhit iu chbiodiesel

v y l phng php dthc hin c tht c phn ng hon ton.

V loi xc tc dng cho phn ng transester ha nh xc tc acid, xc tc

base, xc tc enzyme, xc tc base khng ion. Chng ti sdng xc tc base v phn

ng transester ha khi din ra tng i nhanh v xc tc base t n mn thit b.C nhiu loi xc tc base nhng chng ti chn KOH v n d tm, hiu sut sn

phm cao v tng i rtin.

t c ni dung nghin cu trn, i vi phn ng tng hp du diesel

sinh hc chng ti s tp trung kho st nhng yu tquan trng nht c nh hng

n hiu sut phn ng nh lng ru, lng xc tc, nhit v thi gian phn ng.

Cch kho st nh sau: cnh mt syu tv thay i yu tcn kho st sao cho

lng sn phm biodiesel thu c l nhiu nht v chsacid t gi trnhnht c


41/66



th. Qu trnh kho st c lp li i vi cc yu tcn li trn c ssdng gi tr

tt nht va tm c.

Do chsacid ca du nguyn liu c khnng thay i theo thi gian lu tr

nn ty vo chsacid ca nguyn liu m chng ti la chn quy trnh kho st

cho ph hp. Nu du c chsacid thp (IA5)

th chng ti kho st bng qui trnh 2 bc vi bc u thc hin phn ng ester ha

acid carboxylic nhm hchsacid (IA


42/66



CHNG3

THC NGHIM

-----oooOooo-----i vi nguyn liu c chsacid tdo cao do tn trtrong thi gian di hoc

do bn cht nguyn liu th cn phi thc hin qui trnh hai bc tng hp

biodiesel. Do nguyn liu du trch c tb c ph c chsacid t8,11 19,46

nn chng ti p dng qui trnh tng hp hai bc. Du nguyn liu c xl bng

acid H2SO4m c. Sau sn phm c yn khong 2 gi, tch blp trn, ra

v lm kh sn phm. Tip sn phm c xl bng kim KOH. Sau cho hn

hp phn ng vo phu chit yn khong 15 pht. Sn phm biodiesel th c tin

hnh chit loi bglycerol, tip ra v lm kh sn phm th thu c biodiesel

tinh khit.

S 4 Qui trnh hai bc tng hp biodieselI Giai on ester ha

Trong qui trnh hai bc, nhim vca giai on phn ng u l lm gim ch

sacid ca nguyn liu xung thp hn 5 (IA


43/66



I.1 Cch b tr th nghim:

Btr th nghim theo trt nh sau v mi th nghim lp li 3 ln v ly kt qu

trung bnh.

-

Lng methanol:Thay i lng methanol theo t lmethanol: du ln lt l: 0,35; 0,4; 0,45;

0,5; 0,55 v 0,6

- Nhit phn ng:

Thay i nhit phn ng (C) nhng gi trkhc nhau: 50; 60; 70 v 80

- Thi gian phn ng:

Thay i thi gian phn ng (pht) nhng gi tr khc nhau: 30, 60, 90 v

120.

- Lng H2SO4:

Thay i lng xc tc (%) nhng gi trkhc nhau: 0,5; 1; 1,5 v 2.

I.2 Tin trnh thc hin

Chun bnguyn liu

Cn lng du cn thit v cho vo bnh phn ng.

iu chnh nhit thch hp.

Cn lng methanol cn dng v cho vo bnh phn ng trn v bt u khuy.

Hn hp methanol v du c khuy trong 5 pht, tip cn thn cho lng

xc tc H2SO4m c vo bnh phn ng, tin hnh un nhit cn thit (nu s

dng nhit cao th phi sdng hthng un hon lu trnh tht thot dung mi).

Duy tr nhit phn ng trong thi gian u, thi gian 30 pht vn khuy

nhit phng.

I.3 Tin trnh ra

Hn hp giai on u ny yn trong phu chit khong 2 gi, bpha trn

(lng methanol d, H2SO4d,), pha di c ra nhiu ln vi nc cho n khi

nc sau khi ra c pH bng vi nc dng ra. Sau em sn phm i c quay nhit 70C nhm loi lng methanol v nc ln vo sn phm giai on ny.


44/66



II Giai ontransester ha

II.1 Cch btr th nghim

Cc th nghim c btr theo trt tnh sau v mi th nghim c lp li 3 ln v

ly kt qutrung bnh.

- Lng methanol:

Thay i lng methanol theo tlmethanol: du nhng gi tr: 0,25; 0,3 v

0,35.

- Nhit phn ng:

Thay i nhit phn ng (C) nhng gi trkhc nhau: 40; 50; 60 v 70.- Thi gian phn ng:

Thay i thi gian phn ng (pht) nhng gi trkhc nhau: 30; 60; 90; 120 v

150.

- Lng xc tc KOH:

Thay i lng xc tc (%) nhng gi trkhc nhau: 0,5; 1; 1,5; 2.

II.2 Tin trnh thc hin

Cn lng methanol cn thit cho vo bnh tam gic 100 mL tip theo l lng

xc tc base cn thit. Thao tc cn phi nhanh v methanol dbay hi v KOH dht

m. Cho lng base trn vo bnh tam gic cha sn methanol, dng my khuy t

khuy. Mc ch ca cng vic ny l to ra mui methylate. Do KOH rt kh tan

trong methanol nn cn s dng my khuy t, v di tc dng ca my khuy t

gip cho cc cht phn ng tip xc nhau ddng.

II.3 Tin hnh phn ng

Cn chnh xc lng sn phm phn ng giai on trn cho vo bnh phn

ng v t ln my khuy t, iu chnh nhit cn thit. Cho vo ttdung dch

methanol vo bnh phn ng trn, gn hthng hon lu v tin hnh khuy vi tc

mnh to iu kin cho phn ng xy ra nhanh hn.


45/66



II.4 Tin trnh ra

em hn hp sau phn ng yn trong phu chit khong 15 pht, cho n

khi tch pha r rt. Tch ly phn trn, ra bng nc ct, thng sdng khong 2

ln thtch biodiesel thu c v lp li nhiu ln cho n khi nc sau khi ra c pH

trung tnh.

Sau ra sn phm bng dung dch NaCl bo ha, thng s dng khong

50% so vi thtch biodiesel thu c. Mc ch ra li bng nc mui bo ha l

loi bnc trong sn phm biodiesel.

III Tin trnh lm kh sn phm

Sn phm biodiesel sau khi ra c thbln nc v c lm kh bng mt sphng php:

Chng ct: da vo schnh lch nhit si ca cc cht.

Dng ha cht: khng tc dng ha hc vi biodiesel, c tc dng lam kh

nhanh, r, dtm (thng sdng Na2SO4khan).

Sy chn khng: loi bnc ln trong sn phm bng cch gia nhit trong mi

trng chn khng.

Trong cc phng php lm kh sn phm trn chng ti chn phng php

dng ha cht. Ha cht chng ti s dng lm kh sn phm l Na2SO4 khan. Do

lng sn phm t nn phng php lm kh ny tng i tin li, nhanh.

IV nh gi cht lng sn phm Biodiesel

nh gi cht lng sn phm biodiesel da trn mt s cc ch tiu ha l

nh: pH, acid,


46/66



CHNG 4

KT QU- THO LUN-----oooOooo-----

I CC CH SHA L

I.1 mca b c ph ph thiv hm lng cht bay hi

Sau khi thu b c ph tcc qun c ph trong thnh phv, chng ti em

xc nh m ca b c ph. Kt qum ca mu b c ph trc khi phi c gi

trkhong 61,67%.

Mu b c ph c phi ngoi nng. Sau khi phi xong mu b c ph c

xc nh m. m ca b c ph sau khi phi kh c gi tr khong 6,36%.

m ca b c ph c nh hng n vn tc v kit ca du trch ly[17].

Khi tng lng m slm chm qu trnh khuch tn v lm tng skt dnh cc ht

bt trch ly do m trong bt trch ly stng tc vi protein v cc cht a nc khc

ngn cn sthm su ca dung mi vo bn trong ca cc ht trch ly lm chm qu

trnh khuch tn. Do , m ca b c ph c nh hng n hiu sut trch ly. m b c ph khong 6,36% tng i nh, v thc thtin hnh trch ly du.

I.2 Hiu sut ly trch du bot b c ph ph thi

I.2.1 Phng php ngm dm

T lb c ph v dung mi khong 1:3, ngm trong 10 ngy khi lng du

bo thu c l 10,73g. Hiu sut du thu c so vi khi lng b c ph l:

10,73%.

I.2.2 Phng php trch soxhlet

B c ph c trch ly bng phng php soxhlet c hiu sut du bo thu

c khong 15,27% (phn trm khi lng du bo so vi khi lng b c ph).

I.2.3 Nhn xt

Phng php ngm dm c hiu sut trch ly du bo tb c ph thp hn so

vi phng php trch ly du bo bng phng php soxhlet. V phng php trch

soxhlet c thtrch ly hon ton lng du bo trong b c ph. Nhng phng php


47/66



trch soxhlet c cn n nhit , do vy ta phi cn thn khng nhit qu cao,

c thgy tn tht nhiu dung mi v gy bin tnh du.

I.3 Ch s acid ca du bo

Sau khi b c ph c ly trch du xong, chng ti tin hnh xc nh chsacid ca mu du bo. Kt quchsacid ca du bo nm trong khong t7,439 n

19,46.

II QUY TRNH IU CH BIODIESELT B C PH

Do mu du bo ly trch c c chsacid cao (IA>5). Do quy trnh iu

chbiodiesel ph hp nht l quy trnh hai bc. Bc mt chng ti thc hin phn

ng ester ha. Bc hai l phn ng transester ha.

II.1 Phn ng ester ha

Mc ch trong giai on ny l lm gim chsacid ca sn phm sau phn

ng. V trong phn ng ester ha th lng acid bo t do trong du nguyn liu

chuyn ha thnh biodiesel. V vy, phn ng c coi l c hiu qu nht khi sn

phm sau phn ng c chsacid thp nht c thv phi nhhn 5 (IA


48/66



Bng 2 Cc yu t c nh

Yu tcnh Gi tr

Du bo b c ph 3g

Lng xc tc H2SO4 0,8% (so vi du nguyn liu)

Thi gian phn ng 60 pht

Nhit phn ng 60C

Tc khuy 700 vng/pht

Trong vic kho st nh hng ca lng methanol n phn ng ester ha th

lng methanol ca tng th nghim c thay i cc gi trda trn phn trm khi

lng ca methanol so vi du nguyn liu. Cc gi trphn trm khi lng methanol

so vi du thay i c lit k trong Bng 3.

Chng ti thc hin phn ng trong 60 pht, sau dng phn ng cho sn

phm vo phu chit yn trong 2 gi. Ly pha di, ra nhiu ln vi nc sao cho

nc ra c pH trung tnh. em sn phm c quay chn khng nhit 70C loi

methanol cn d v nc trong sn phm. Sau xc nh chsacid, kt quc

trnh by Bng 3.

Bng 3nh hng lng methanol n ch s acid

Lng methanol

(% methanol so vi du) 35% 40% 45% 50% 55% 60%

Chsacid (IA) 2,275 1,85 1,678 1,463 1,331 1,009


49/66



2.275

1.85

1.678

1.4631.331

1.009

0.000

0.500

1.000

1.500

2.000

2.500

35% 40% 45% 50% 55% 60%

Lng methanol

Chs

acid

Hnh 1 nh hng ca lng methanol n ch s acid

Qua Bng 3 v Hnh 1 ta nhn thy: phn trm khi lng methanol so vi du

khong t 35-45% th ch s acid h xung nhanh. Nhng phn trm khi lng

methanol so vi du nguyn liu 45-60% th chsacid hxung khng nhiu. tit

kim lng methanol, trong phn ng ester ha kho st nh hng lng methanol

th chng ti chn phn trm khi lng methanol so vi du nguyn liu l 45%. V

th, ta cnh gi trphn trm khi lng methanol v du l 45% i tip kho st

cc nh hng khc.

II.1.2 nh hng ca nhit phn ng

kho st nh hng ca nhit n ester ha th chng ti cnh cc yutnhlng du, lng xc tc, lng methanol, thi gian phn ng v tc khuy.

Cc yu tcnh c gi trc trnh by Bng 4. Nhit phn ng c thay

i cc gi tr50C, 60C, 70C v 80C.

Bng 4 Cc yu t cnh

Yu tcnh Gi tr

Du bo b c ph 3g

Lng xc tc H2SO4 1% (so vi du nguyn liu)

Lng methanol 45% (so vi du nguyn liu)


Tc khuy 700 vng/pht


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Sau 60 pht, cho dng phn ng, em phn ng cho vo phu chit yn 2

gi, tch ly lp di, ra hn hp sn phm nhiu ln vi nc cho n khi nc ra

c pH trung tnh. Mi th nghim lp li ba ln, tnh trung bnh cng v kt quc

trnh by trong Bng 5 v minh ha bng Hnh 2.

Bng 5nh hng ca nhit phn ngn chs acid

Nhit phn ng 50C 60C 70C 80C

Chsacid 4,34 1,697 0,806 1,54

4.34

1.679

0.806

1.54

0

0.5

1

1.5

2

2.5

3

3.5

4

4.5

5

50C 60C 70C 80C

Nhit phn ng

Chs

acid

Hnh 2nh hng ca nhit n ch s acid

Qua Bng 5 v Hnh 2 ta thy: nhit phn ng c nh hng ln n chs

acid ca hn hp sau phn ng. nhit t50-70C, chsacid t4,34-0,806, cho

thy nhit cng tng th chsacid htheo, do tng nhit th qu trnh phn ng

xy ra nhanh hn. Nhngnhit t70-80C th chsli tng t0,806-1,54, v nhit

tng cao th lng methanol bbay hi lm nh hng n phn ng. Nhit ti

u cho giai on ny nm 70C. V vy, chng ti cnh iu kin nhit 70C

v 45% lng methanol (phn trm khi lng methanol so vi du nguyn liu)

kho st tip cc nh hng ca yu tthi gian phn ng.

II.1.3 nh hng ca thi gian phn ng

kho st nh hng ca thi gian phn ng, chng ti thc hin cc phn

ng vi thi gian thay i cc gi tr30 pht, 60 pht, 90 pht v 120 pht. Cc yu

tcn li c cnh. Gi trcc yu tcnh c lit k Bng 6.


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Bng 6 Cc yu tcnh

Yu tcnh Gi tr

Du bo b c ph 3g


Lng xc tc H2SO4 1% (so vi du nguyn liu)

Nhit phn ng 70C

Tc khuy 700 vng/pht

Sau tng gi tr thi gian thc hin phn ng chng ti cho dng phn ng,em phn ng cho vo phu chit yn 2 gi, tch ly lp di, ra hn hp sn

phm nhiu ln vi nc cho n khi nc ra c pH tng ng vi nc trc khi

ra, em c quay v xc nh chsacid hn hp. Mi th nghim lp li ba ln, tnh

trung bnh cng v kt quc trnh by trong Bng 7 v minh ha bng Hnh 3.

Bng 7nh hng ca thi gian phn ng n chs acid

Thi gian phn ng 30 pht 60 pht 90 pht 120 pht

Chsacid 2,313 1,69 0,743 1,089

2.313

1.690

0.743

1.089

0.000

0.500

1.000

1.500

2.000

2.500

30 pht 60 pht 90 pht 120 pht

Thi gian phn ng

Chs

acid

(IA)

Hnh 3nh hng ca thi gian phn ng n ch s acid

Qua Bng 7 v Hnh 3 ta thy: thi gian phn ng nh hng nhiu n chs

acid ca sn phm sau giai on ny. khong thi gian t30 pht n 90 pht chs


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acid t2,313 hxung 0,743. Nhng t90 pht n 120 pht th chsacid bt u

tng t0,743 ln 1,089 do phn ng ester ha l phn ng thun nghch, nn cn mt

khong thi gian phn ng t trng thi cn bng nhng nu thi gian qu di s

to iu kin cho cc qu trnh khng mong mun xy ra tc l lm tng chsacid.

Qua kho st ny cho thy thi gian phn ng 90 pht l iu kin thi gian ti u

nht. Ta cnh yu tthi gian phn ng 90 pht kho st nh hng ca lng

acid i vi phn ng ester ha.

II.1.4 nh hng lng acid H2SO4

kho st nh hng ca lng acid H2SO4, chng ti thay i lng acid

cn dng trong phn ng nhng ng thi cnh cc yu t: lng du nguyn liu,

lng methanol, nhit , thi gian, tc khuy. Cc gi trca cc yu tcnhc trnh by Bng 8.

Bng 8 Cc yu t c nh

Yu tcnh Gi tr

Du bo b c ph 3g



Nhit phn ng 70C

Tc khuy 700 vng/pht

Sau 90 pht, cho dng phn ng, em phn ng cho vo phu chit yn 2

gi, tch ly lp di, ra hn hp sn phm nhiu ln vi nc cho n khi nc ra

c pH trung tnh, em c quay v xc nh chsacid hn hp. Mi th nghim lp li

ba ln, tnh trung bnh cng v kt quc trnh by trong Bng 9 v minh ha bng

Hnh 4.


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Bng 9nh hng ca lng xc tc H2SO4n ch s acid

Lng xc tc H2SO4 0,5% 1% 1,5% 2%

Chsacid 5,678 0,57 0,5589 0,7736

5.6780

0.5700 0.5589 0.7736

0.0000

1.0000

2.0000

3.0000

4.0000

5.0000

6.0000

0.50% 1% 1.50% 2%

Lng xc tc

Chs

acid(IA)

Hnh 4nh hng ca lng xc tc H2SO4n ch s acid

Qua Bng 9 v Hnh 4 ta thy: Lng xc tc acid H2SO4c nh hng ln n

chsacid ca sn phm sau phn ng giai on ny. Khi phn trm khi lng xc

tc so vi du nguyn liu t0,5-1% th gi tracid gim t5,678 n 0,57. Nhng khi

tng lng acid th chsacid c chiu hng tng t0,57-0,7736. iu ny c giithch l do phn ng ester ha l mt phn ng thun nghch v sau phn ng c sinh

ra nc. Nc sinh ra lm gim nng acid sulfuric. Acid sulfuric ngoi vai tr lm

xc tc, cn c chc nng ht nc. Do khi tng lng acid th hiu quphn ng

tt hn (chsacid gim nhiu hn). Nhng nu dng qu nhiu acid, hiu sut phn

ng gim v acid cng c kh nng proton ha oxygen ca nhm hydroxyl ca

methanol to thnh ion methyl oxonium. iu ny dn ti s cnh tranh to thnh

olefin tru tlm gim tnh hiu quphn ng (chsacid cn cao). Ty cthkt lun lng xc tc H2SO4sdng l 1% so vi lng du l iu kin ti u

nht.

II.1.5 iu kin ti u ca giai on ester ha

Lng xc tc H2SO4: 1% (so vi nguyn liu du bo b c ph)

Lng tc cht methanol: 45% (so vi nguyn liu du bo b c ph)

Tc khuy: 700 vng/pht


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Thi gian phn ng: 90 pht

Nhit phn ng: 70C

Sau giai on ny sn phm c chsacid khong 0,57. Chsacid di 5 cho

php ta i tip giai on sau.

II.2 Phn ng transester ha

Phn ng transester ha nhm mc ch chuyn ha triglyceride thnh

biodiesel. Phn ng c xem l c hiu qukhi schuyn ha ny xy ra hon ton,

sn phm biodiesel to thnh c chsacid thp v cho hiu sut cao nht. Da vo

gi trchsacid v hiu sut phn ng chng ti tm iu kin ti u ca phn ng.

II.2.1 nh hng ca lng methanol

kho st nh hng ca lng methanol n mc chuyn ha ca phn

ng th lng methanol sdng c thay i theo phn trm khi lng so vi khi

lng sn phm ca giai on ester ha. Cc gi trkho st nh sau: 25%, 30%, 35%,

40%, 45%. Trong khi cc yu tphn ng khc c cnh. Cc gi trca cc

yu tcnh c lit k Bng 10.

Bng 10 Cc yu t c nh

Yu tcnh Gi tr

Sn phm giai on ester ha 3g

Lng xc tc KOH 1,5% (so vi sn phm giai on ester ha)


Nhit phn ng 60C

Tc khuy 700 vng/pht

Thi gian thc hin phn ng l 60 pht. Sau 60 pht cho dng phn ng, em

phn ng cho vo phu chit yn khong 15 pht cho tch thnh 2 pha r rt, tch

ly lp trn, ra hn hp sn phm nhiu ln vi nc cho n khi nc ra c pH


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trung tnh v dung dch nc ra trong. Mi th nghim lp li ba ln, tnh trung bnh

cng v kt quc trnh by trong Bng 11 v minh ha bng Hnh 5.

Bng 11nh hng lng methanol n ch sacid v hiu sut ca sn phmbiodiesel

Lng methanol 25% 30% 35% 40%

Chsacid 0,262 0,276 0,328 0,382

Hiu sut 60,4% 67,7% 74,69% 64,18%

0.262 0.2760.328

0.382

60.40%

67.70%

74.69%

64.18%

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

25% 30% 35% 40%

Lng methanol

Ch s acid

Hiu sut

Hnh 5nh hng lng methanol n ch s acid v hiu sut ca sn phmbiodiesel

Da vo Bng 11 v Hnh 5 ta thy: khi phn trm khi lng methanol so vi

khi lng sn phm ca giai on ester ha t25-35% th chsacid ca sn phm

biodiesel l: 0,262; 0,276; 0,236, cc gi tracid gn nh tng ng nhau. Nhng

khi lng methanol tng dn ln th hiu sut cng tng dn ln v y l phn ng

thun nghch nn khi tng hm lng mt trong hai tc cht th hiu sut phn ng s

tng theo, nhng v phn ng lc ny t trng thi cn bng nn d c tng lng

methanol ln th hiu sut gn nh khng thay i. Nhng khi phn trm lng

methanol tng ln t35-40% th hiu sut li gim. V methanol tan tt trong glycerol

v biodiesel, lm chm qu trnh tch lp ca sn phm gy kh khn v tng chi ph

cho qu trnh ra sn phm, lm gim hiu sut phn ng. Do vic sdng ru

cng phi ng liu lng, trnh hao tn ru khng cn thit. Theo Hnh 5 ta thy khiphn trm khi lng methanol so vi sn phm giai on ester ha l 35% th sn


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phm c hiu sut cao nht v chsacid thp. Vy phn trm khi lng methanol so

vi sn phm giai on ester ha 35% l ti u trong giai on ny

II.2.2 nh hng ca nhit phn ng

Da trn mt syu tcnh tin hnh kho st phn ng trn c sthay inhit phn ng nhng gi trkhc nhau.

Bng 12 Cc yu t c nh

Yu tcnh Gi tr

Sn phm giai on ester ha 3g

Lng xc tc KOH 1,5(so vi sn phm giai on ester ha)


Lng methanol 40%(so vi sn phm giai on ester ha)

Tc khuy 700 vng/pht

Sau 60 pht, cho dng phn ng, em phn ng cho vo phu chit yn

khong 15 pht cho tch thnh 2 pha r rt, tch ly lp trn, ra hn hp sn phm

nhiu ln vi nc cho n khi nc ra c pH trung tnh v dung dch nc ra

trong. Mi th nghim lp li ba ln, tnh trung bnh cng v kt quc trnh by

trong Bng 13 v minh ha bng Hnh 6.

Bng 13nh hng nhit phn ng n ch s acid v hiu sut ca sn phmbiodiesel

Nhit phn ng 40C 50C 60C 70C

Chsacid 0,385 0,224 0,272 0,282

Hiu sut 70,24% 71,83% 68,81% 63,31%


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0.385

0.2240.272 0.282

70.24% 71.83% 68.81%63.31%

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

40C 50C 60C 70C

Nhit phn ng

Ch s acid

Hiu sut

Hnh 6 nh hng nhit phn ng n ch s acid v hiu sut ca sn phmbiodiesel

Qua Bng 13 v Hnh 6 ta thy: khi nhit phn ng l 50C th hiu sut

biodiesel thu c kh cao. Nhng khi tng nhit ln 60-70C th hiu sut

biodiesel c chiu hng gim. iu ny chng tnhit c tc dng xc tin cho

phn ng. Khi tng nhit th khnng ha tan ca du v methanol tt hn lm cho

phn ng chuyn ha tt hn. Nhng nhit qu cao th mt phn lng methanol s

bha hi. Mc khc, nhit qu cao c thdn n phn hy sn phm hoc phn

ng s xy ra theo cc qu trnh khc lm gim hiu sut biodiesel. TBng 13 v

Hnh 6 ta thy khi thc hin phn ng 50C th

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