KHOA HQC CdNG NGH|
X A C DflXIH THOIMG S O COIMG IVGHE T O I LIU E P T A O VIEJM IMHIEIX! LIELI T U P H E
T H A IC H E BIEiV G d
. Le Vdn TliiiS Phan Tiing Hung^
T6MTAT
O nude ta, hang nam phe thai tir nganh cong nghiep chd bidn gd khoang vai trdm ngan tin. Phin Idn lupng phd thai nay dd lai ngoai tu nhien gdy 6 nhi^m mdi trudng va ldng phi mpt lupng nguyen lieu dang kd. Vi vdy. neu su dung nguon phd diai nay dd nen tao vifen ddt phue vu san xuit vd ddi sdng xa hpi, giam chi phi vdn chuydn va luu tru, vira cdt giam nang lupng hda thach, vira giam lupng khi thai gdy hieu ling nha kinh va lam cho mdi trudng trong sach. Dd co ca sd hoan tiiien cdng nghe va tiiidt kd cdc thidt bi Uong ddy chuyen san xuat vien nhien lieu tu phd thai chd bidn gd tiii truoc tien cin xdc dinh cac tiiong sd cong nghe toi uu. Bdng phuong phap ly thuy^t kdt hpp vdi nghien cuu thuc nghiem da xdy dung duoc mo hinh toan hpc bi^u hien su anh hudng dpc lap cua tung ydu td cung nhu su anh hudng ddng thdi ciia cac ydu td do den chat lupng vien nhien liSu (dupe danh gia thdng qua dp bdn co hpc va nhiet nang toa ra khi ddt). Tren CO sd cac mo hinh toan hpc tim dupe, ap dung phuong phap tim cue tri cua ham nhieu bidn dd xac dinh dupe cac thong s6 cong nghe toi uu (dp suit, nhiet dp va thdi gian ep) phue vu san xuit vien nhien beu ttr phd thai chd bidn gd mpt cdch hieu qua n h i t
Tirkhod: Unhin, ma tran thirc nghiSm, phd thai chd bidn gS, quyho^ch hda thucnghiim, sinh khdi, thuc nghi$m don ydu td, thucnghi$m da ydu to, thdng sd cong ngh$ tdi uu.
LDATVANOE
Viet Nam la mOt nude ndng nghiep, hang ndm thai ra mOt lupng Idn ddn hang chyc triOu tin phd thai tir sin xuat (trau, bd mia, rom ra, vd hat, mun cua, ddm bdo, gd vyn...). Sir dung ngudn sinh khdi nay mOt each thich hpp dd sin xuit nhiet vd diOn ndng se dem lai co hOi mdi cho ndng nghiep, cai tiiien an ninh ndng lupng vi mang lai Ipi ich cho mdi hirdng vi xd hOi. Thdng tiiudng thi phd thii tir chd bidn gd chidm tdi 20% so vdi nguyen UOu. Theo didu h-a ciia Hidp hdi Go Viet Nam, lupng phd lieu hr cdng nghiep chd bidn gd khoang 300000 tin/ndm vd cd khoing hon 60% lupng phd thai nay hi thii ra mdi trudng. Vi thd, ndu chiing ta su dung ngudn phd tiiii nay nen tao vien ddt la each bidn chiing tiianh ndng lupng dd phyc vu sin xuat vi ddi sdng xa hOi, giam chi phi vgn chuydn vi luu tru, vita cit giim ndng lupng hda tiiaeh, vira giam lupng khi tiiii gay hidu ung nhi kinh gdp phin bio vd mdi hudng. Do vky, viec diu tu nghidn cuu vi ling dyng cdng ngh$ t?o vien nhien lidu tir phd tiiii ehd bidn gd dang md ra hudng su dyng ngudn ndng lupng mdi, mang lai Ipi ich mdi hirdng vi dim bio an nmh ndng lupng cho cic qui tiinh phit tiidn kinh td bdn viing. Xuit phdt hr yeu ciu tiiuc tidn ndi ti-en, viec nghien cuu xdc dinh cic tiidng sd cdng nghe tdi uu khi nen tao vien nhien lieu tir phd tiiii chd bidn gd Id cin tiiidt vi cip ' Trudng D?! hpc Lam nghi?p
^ Vi?n Khoa hpc Ldm nghi?p
bich. Kdt qua nghien cuu dat dupe gdp phin hoin thiOn cdng nghe va lam tidn dd cho viOc thidt kd cic thidt bj trong day chuydn sin xuit vien nhien Ueu tir phd tiiii.
L PHUONG PHAP NGHiN CUU
1. Phirong phip nghien cthi 1^ thuydt
Tim hidu thdnh phin, tinh chit co, ly, hda ciia nguyen liOu tao vien nhien UOu hr ly thuydt ciu tao gd.
Tim hidu, thu thdp cic tai lieu hen quan dd xic dinh mdt sd tinh chit vdt ly ciia nguyen lieu (khdi lupng rieng, nhiet dung rieng, nhiet ndng...).
2. Phuong phdp nghien ciiu thuc nghiem a. NghiSn cuu thuc nghiSm don ydu td
Tidn hanh thi nghiOm vdi timg ydu td thay ddi (cdn cic ydu td khic cd djnh) vdi sd mire khdng nhd hon 4, khoing thay ddi Idn hon 2 lin sai sd binh phuong trung binh ciia phdp do gii trj thdng sd dd.
b. NghiSn oiu thuc nghiSm da ydu to
Nghien ciiu thuc nghiem da ydu td la xic dinh quy ludt vd miic dO inh hudng ddng thdi ciia cic ydu td diu vdo (thdng sd cdng nghe dp tao vien) ddn cac thdng sd diu ra (chat lupng ciia vien nhien UOu). Kdt qui thu dupe la co sd dd xdc dinh gii tri tdi uu ciia cic thdng sd cdng nghe phyc vu sin xuit vien nhien U^u.
N 6 N G NGHIfP VA PHAT TRIEN N 6 N G T H 6 N KY 2 - THANG 7/2011 89
KHOA HOC CdNG NGHE
• . K H QUA VA THAO LUAN
1. Nghien ciiu ly thuydt
Gd do nhidu td bio ciu tao nen, nd la mOt thd hdn hpp rit phiic tap ciia cic chit cao phdn tir Polisaccarit gdm nhdm cacbonin vi nhdn benzen tao thaiJi. Ngodi ra trong gd cdn cd diu nhua, chat chit, chit miu, chit beo. Trong gd, xenlulo chidm khoing mdt nua. Xenlulo va Unhm la tiianh phin chii ydu ciu tao len vach td bao. Linhm li chit bOt miu nau sam, thuOc loai cacbua vdng cao phan tir cd thanh phin cau tao rit phiic tap. Trong gd cd ty le thinh phin hnhin chidm khoing 17 - 30%, nd la chit keo (chat kdt dinh) dd hen kdt cic td bao vdi nhau de tao thanh khdi virng chic. Dd giii phdng linhin trong gd thudng sir dung phuong phap nhiet phan, kdt qui nghien cuu cho thay nhiet dO dd linhm bit diu giai phdng la > 170°C [5]. Day chmh la mOt trong nhiing kdt ludn quan trpng dd lira chpn cdng nghe cung nhu gii tri nhiet dO tdi thidu de gia nhiet khi dp tao vien tir mun cua khOng can sir dyng chat phu gia.
2. Nghito cuu tfauc n g h i ^ a. Chuin bi tin nghiSm Chuin bi thidt bi thi nghiSm
Khudn ep va bd phin gia nhiSt Khudn dp Id bd phan hdt siic quan trpng. Theo Hoang Nguydn Thu Ha [2] thi khi ep vien nhien Ueu cin nhiet dO cao va ip suit Idn (nhiet dO len tdi hing trdm dO, ip suit len tdi hing chue Mpa). Vdi duong kinh vien nhien Ueu tuong duong vdi dudng kinh ciia vien than td ong (d
= 100 - 130 mm). Dd thda man yeu ciu tren dd lua chpn cdp xi lanh pittdng ciia dOng co D65 lam khudn dp phyc vu thi nghiem.
BO phan gia nhiet dupe thidt kd gdm cic vdng day dien trdr quin bao quanh khudn dp (xi lanh) dd gia nhiet ( c ^ nhiet) trong qui trinh dp. Khi ep vien nhien Ueu thi nhiet dO gia nhiet cd thd len tdi 700 - 800°C [2] Sir dung ngudn dien ba pha dd ddt ndng day dien trd dat nhiet dO cue dai tdi LOOCC va cd the didu chinh nhiet dO dp theo y mudn nhd tiiidt bi didu chinh vi hidn th} nhiet dO (hinh 1).
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Hmh 1. Khudn €p vk tiiidt b) didu chinh vi hidn tfa| nhiet dO dp Thiet bfSp:
Ep tao vien: Sir dyng miy dp vin nhdn tao tai Phdng tiii nghiem tinh chit vdt Ueu gd (VILAS 309;
ISO/IEC 17025:2005) Khoa Chd bidn lam san Trudng Dai hpc Lam nghiep (hinh 2a). Miy cd thd
ip suit dp vien nhien Udu ein thidt < 30 Mpa Xic dinh tinh chat co hpc dia vien: Sir dyng miy tiiir co ly tinh ciia gd (Qtest/25) (hinh 2b) tai Phdng tiii nghiem tinh chit vat Ueu gd (VILAS 309;
ISO/IEC 17025:2005) Khoa Chd bien lim sin dp tdi ip suit dat 50 Mpa, thda man so vdi yeu cau Trudng Dai hpc Lam nghiep.
(a) (b) Hinh 2. Cic thidt b} ep vi thu co tinh vien nhien Udu
90 NONG NGHllP VA PHAT TRIEN NONG T H 6 N - KY 2 THANG 7/2011
KHOA Hpc CdNG NGHl
+ Lua chpn deydu tddiu vio vi him muc tiSu Chat lupng ciia vien nhien Ueu phy thuOe vio nhidu ydu td nhu : hp suit ep, nhiet dO dp, loai vdt lieu, kich thude, dO im cua nguyen Ueu dua vdo ep....
Tham khio kdt qua nghien ciiu cua Hoang Nguydn Thu Ha [21, chpn cac ydu td anh hudng chinh vd hdm
myc tieu dd nghien ciiu nhu sau:
- Ydu td anh hudng chinh Id dp suit (P); nhiet dO (t^va thdi gian (D.
- Ham muc tieu: Chit lupng vien nhien Ueu dupe ddnh gii thdng qua cic chi tieu: NhiOt lupng tda ra khi ddt va dO Uen kdt cac hat miin cua thanh khdi vung chic dd khdng hi vd khi di chuydn vi sir dyng chiing.
Nhiet lupng ciia vien dupe dinh gii giin tidp thdng qua mat dO vien ( p ) theo cdng thiic [5]:
Trong dd: Q^ - nhiet lupng chiy tinh theo don vi khdi lupng (kcal/kg); p khdi lupng thd tich kg/dm^
DO bdn eo hpc ciia vien dupe danh gii thdng qua ling suit nen vien (o).
Do vdy chi tieu dinh gii chit lupng ciia vien nhien lieu quy vd cac thdng sd la khdi lupng tiid tich
{p)vk ling suit nen vien (o).
+ Xic dinh gii tii cic ydu tddiu vio va muc thi nghiSm
Qua kdt qui nghien cuu ly thuydt, kdt hpp tham khao kdt qua ciia Hoang Nguydn Thu Hi [2] va cic till nghidm khao sit ban diu trong nghien ciru niy dd xic djnh dupe gii trj vi khoang bidn thien cua cic ydu td diu vio cho qui trinh quy hoach hoi thuc nghidm nhu sau:
+ Khoang bidn tiiien ddi vdi nhiet dO dp (t°): Kdt qui nghien cuu ly thuydt chi ra ring: Trong gd, ty le cua Unhin chidm tir 17 - 30%, nd li chit keo dd kien kdt cic td bio vdi nhau A^ tao kdt ciu gd vung chic vd nhiOt dd dd Imhm bit diu giii phdng li >170°C.
Do vdy, mudn tao dupe vien nhien Ueu cd dO kdt dinh vung chic mi khdng cin trOn phu gia tiii trong qud hinh dp cin lam cho linhin ndng chay, nghia li nhiOt dp ep phii tiida mdn >170"C [5]. Vi tiid dd chpn nhi^t do dp tdi tiiidu li: T ^ = 200°C. Ddng tiidi qua mOt sd tiii nghidm ban diu (ip suit, tiidi gian) khdng ddi cho tiiiy khi nhidt dO dp dat 300°C tiii bd mdt
N 6 N G NGHIfP VA PHAT TRIEN N 6 N G T H 6 N - KY 2 THANG 7/2011
xung quanh vien nhien Ueu bit dau chay nen dd chpn nhiOt do dp cao nhit liT^^, = 300°C.
+ Khoang bidn thien ddi vdi thdi gian ep (T):
Thdi gian ep quydt dinh ddn viec tao Uen kdt vien nhien UOu [2]. Qua mOt sd thi nghiem thdm dd vdi (nhiet do, ip suit) khdng ddi cho thiy d thdi gian T >
5 phiit thi vien nhien Ueu mdi tao dupe Uen kdt vd d thdi gian T < 15 phiit tiii vien nhien UOu khdng hi chdy bd m$t Do vdy, dd chpn thdi gian ep tdi thidu la T„i„ = 5 phiit vd tdi da Id T ^ = 15 phiit.
+ Khoing bidn thien ddi vdi ip suit dp (P):
Thuc hien mOt sd thi nghiOm thdm dd [3] (thdi gian va nhiet dO khdng ddi) cho thiy, d ip suit P > 5 MPa thi vien nhien Ueu bit diu tao Uen kdt, cdn d ip suit P > 10 Mpa tiii vien nhien Ueu bit diu chiy. Do vdy da chpn dp suit dp tdi tiiidu la Y,^ = 5 Mpa va tdi
dalaP„3,^ = 10MPa.
b. Nghiin ciiu thuc nghiSm don ydu td
+ Nghiin ciiu inh hudng dpc lip aia ip suit, nhiStdd, thdi gian ep ddn dd bSn cahpc ciia viin
Dd tidn hinh nghien ciru inh hudng dOc Idp ciia cic ydu td (ip suit, nhiOt dO vi thdi gian dp) ddn dO bdn CO hpc ciia vien nhien UOu dd tidn hdnh tao vien nhien UOu bing cich cho timg ydu td thay ddi (cdn cic ydu td khic cd djnh). Cic vien nhien UOu tao ra tir cac thi nghiOm dupe do dO bdn co hpc tren mdy ep QTEST; kdt qui tiiu dupe tidn hanh xir ly nhd phin mdm quy hoach thuc nghiem OPT nhu sau:
- Phuong trinh anh hudng ciia ciia ip suit dp (P) tdi do bdn co hpc (o) ciia vien nhien lidu:
y = 4,189 - 0,064x + 0,009;c^ (1) - Phuong trinh inh hudng ciia nhi^t dO dp (t") tdi
do bdn eo hpc (o) ciia vien nhien Ueu:
>; = 4 , 3 1 9 + 0,007;C + 0,001JC^ (2)
Phuong trinh inh hirdng ciia tiidi gian dp (T) tdi do bdn co hpc (o) ciia vien nhien UOu:
y = 4,229 + 0,042x + 0,00 Ix' (3) Tir cic phuong tiinh (1, 2, 3) ta xdy dung dupe
dd thj bidu th} su anh hudng ciia ip suit, nhidt dd vi thdi gian dp ddn dO bdn co hpc ciia vien nhien lidu nhu hinh 3a, 3b va 3c.
91
KHOA HOC C 6 N G NGHfi
Anh huvng ciu ip suat t i i dp ben cv hfc
Apfut
Anh hiroDg cua nhi(t dp t6i d$ ben cv hf c
4 55
i *5
^445
; 44 S435 r 43
4.25
240 270 300
(a) (b) (c) Hmh 3. Dd th; inh huong dOe lip ciia ip suit, nhi^t dO, tiidi gian dp ddn dO bdn co hpc ciia vien
(a) Dd till inh hudng eda ip suit (P) tdi dd bSn cahpc (a ) cua viSn nhiSn USu; (b) Dd tiii inh hudng cda nhiStdd (C) tdi dd bSn cahpc (cr ) cua n'Sn nhiin Ueu; (c) Dd tiii inh hudng cua tiidi gian ep (T) tdi dp bSa cahpc (G ) cda viin nhiin liSu
+ Nghiin ciiu inh hudng ddc lap cda ip suit, nhiSt dp, thdi gian Sp ddn khdi lupng tiid tich cua
viSn nhiSn liSu
Phirong trinh anh hirdng cua ciia ip suit ep (P) tdi khdi lupng thd tich (p) ciia vien:
y = 0,124-0,017x +0,005x2 (4) - Phuong trinh anh hudng ciia nhiet dO ep (t°) tdi khdi lupng thd tich (p) ciia vien nhien Ueu:
y= 0,212-0,05x +0,05x2 (5) Phuong trinh anh hudng cua thdi gian ep CD
tdi khdi lupng thd tich (p) ciia vien:
y= 0,222-0,01x +0,001x2 (g) Tir kdt qua xir ly sd Udu ta xay dung dupe dd thi inh hudng ciia ip suit, nhiet dO vi thdi gian dp ddn khdi lupng thd tich ciia vien nhien Ueu 0 hinh 4a; 4b
va4c.
Anh hirong ciu i p suit t6i khoi lurpg rieng
.0.5 I 0.4 f0.3i
ro.2
[0.1 ' 0
9 Apiiui
Anh hiromg cut nhift df tori khoi h r ^ rieng
~i0.6
MO.4
• ZO.2
S n
200 240 270 300
Nlii(ld$
310
(a) 0)) (e) Hmh 4. Dd th| inh hudng ddc I ^ ciia ^ suit, nhiOt dO, thdi gian dp ddn (p) ciia vien nhien UOu
(a) Dd thi inh hudng cua ip suit (P) tdi khdi lupng thd tich (p) cua viin nhiin h'Su; (b) Dd thi anh hirdng ciia nhiStdd (f) tdi khdi lupng the tich (p) cua viSn nhiSn liSu; (c) Dd thi inh hudng cua thdi gian ep (I) tdi khdi lupng thd tich (p) cua viSn nhiin USu
Qua hinh 4 cho thiy: Anh hudng ciia cic yeu td diu vio (ip suit, nhiet dO vi tijdi gian dp) ddn cic ham myc tieu (dO bdn co hpc vi khdi lupng thd tich ciia vien nhien Ueu) li ding kd va tuan theo quy luat ham bac hai.
c. NghiSn cuu thuc nghiSm da ydu td
Kdt qua thuc nghiem don ydu td (hinh 3 va 4) cho tiiiy, quy ludt va miic dO anh hudng ciia tirng yeu td diu vio (ap suit dp, nhiet dO dp vi thdi gian ep) ddn cac ham muc tieu (ung suit nen va khdi lupng thd tich ciia vien nhien lieu) la ham bde 2 nen khdng can tidn hanh quy hoach thuc nghiem bic mpt ma thuc hidn ngay quy hoach thuc nghiem bic
hcu theo phuong in ciia Harly [3]: cac budc tidn hanh nhu sau:
+Ma hda, gii tii vi muc bidn tiiiSn cda cic ydu tdinh hudng: Md hda cic ydu td anh hudng nhu sau:
Xi bidu hi^n cho ydu td anh hudng li ip suit dp P; X2 bidu hi^n cho ydu td anh hudng li nhidt dO dp t°; X3 bidu hidn cho ydu td anh hudng li thdi gian dp T.
Gii tri vi khoang bidn thien ciia cic ydu td anh hudng dupe chpn dua vio kdt qua nghidn ciiu ly thuydt d muc "Xic dfnh gii tii dc ydu tddiu vio vi miic thi nghiSm'^, ky hidu dang md hda vi mire bidn thien cua cic ydu td anh huong dupe ghi 6 bang 1.
92 NONG NGHIEP VA PHAT TRIEN NONG T H 6 N KY 2 - THANG 7/2011
KHOA Hpc C 6 N G NGHl
Bari^ ,. K y h i e u m a h d a v i miic bidn thien ciia cic ydutd inhhitdog
+ Xiy dung ma trin thi nghiSm: Ma trdn thi nghiem dupe xay dung tiieo phuong p h ^ ciia Harly nhu dbang 2.
Bic TT
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
ig 2. Bing X,
-1 +1 -1 +1 -1 +1 -1 +1 -1 +1 0 0 0 0 0
ma trdn th X,
-1 -1 +1 +1 -1 -1 +1 +1 0 0 -1 +1
0 0 0
nghiem X
-1 -1 -1 -1 +1 +1 +1 +1 0 0 0 0 -1 +1 0
Tidn hinh thi nghiem theo ma trdn ciia Harly dd Idp vdi sd lin Idp lai ciia moi tiii nghidm m - 3; kdt qui thi nghiem tiiu dupe tidn hanh xir ly nhd phin mdm OPT.
+ Kdt qui xdlysd USu thi nghiSm:
Anh hudng ddng thdi cua ip suit, dO im, thdi gian dp ddn khdi lupng tiid tich ciia vien nhien Ueu
Xic dinh md hinh toin vi thue hiSn cic phep tinh kidm tra
Md hinh todn hpc cd dang:
p = 0,297 + 0,017 Xi - 0,098Xi2 0,041X2 - 0,014X2X1 + 0,012 Xz^ + 0,029X3 - 0,019X3X1 -
0,036X3X2 + 0,042X32 + hd sd (7) Dinh gii ddng nhit phuong sai theo didu kidn:
Gtt<Gb
Tieu chuin Kohren G^ = 0,1687
Tieu chuin Kohren tra bing Gb = 0,4069
Gtt < Gb tinh ddng nhit cua phirong sai dat tieu chuin.
Kidm tra miic y nghia ciia cdc he sd: Sir dung tieu chuin Student dd kidm tra nhung he sd cd y nghia ndu thda man didu kien: ttt>tb
Gii til trung binh ciia a = 0,05; 9 = N(n-1) = 15 (3-1) = 30, ti-a bing dupe tb = 1,7.
Ddi chidu vdi bing trong tii Ueu ciia Le Cdng Huynh [3] thi tit ca cic he sd ciia phuong trinh (7) ddu thda mdn didu kiOn t^ > tb, vdy chiing ddu cd y nghia.
Kidm tra tinh tuong thich ciia md hinh: F^ = 0,49 <Fb = 2,04 => md hinh todn hpc tuong tiiich.
Chuydn phuong trinh hdi quy tir dang mi sang dang thue:
Thay thd cic gii tq ma hda Xi = (Xi -7,5)/2,5 = 0,4X1- 3; X2 = (X2 - 250)/50 = 0,02X2 - 5; X3 = (X3 - 10)/5 = 0,2X2 - 2 vio phuong tiinh hdi quy (7) vd thay cic ky hidu Xi bing P, X2 bdng f vk X3 bing T.
Sir dyng phin mdm OPT tim ra phuong trinh dang thuc ciia him khdi lupng thd tich nhu sau: p = 0,719 + 0,019P - 0,0157P2 - 0,000886t - 0,00011tP + 0,0000047t2 + 0,02T 0,0015TP 0,00014Tt +
0,00167T2 (8) Nghien ciiu inh hudng ddng thdi ciia dp suit,
do im, thdi gian dp ddn dO bdn co hpc ciia vien nhien Ueu
Xic dinh md hmh toin vi thue hiSn cic phSp tinh kidm tra
Md hinh toin hpc cd dang: o = 4,410 + 0,039Xi - 0,125X2 0,055X2+ 0,007X2X1 + 0,049x2+0,066X3-
0,002X3X1-0,057X3X2+0,075X' (9) Ddnh gii ddng nhat phuong sai theo didu kidn:
Gt,<Gb
Tieu chuin Kohren G^ = 0,3239; tieu chuin Kohren h-a bang Gb= 0,4069.
Gtt < Gb tinh ddng nhit ciia phuong sai d?it tieu chuin.
Kidm tra miic y nghia ciia cic h^ sd: Sir dyng tieu chuin Shident, nhirng hd so cd y nghia khi: !«> tb
Gii tri trung binh ciia a = 0,05; <p = N(n-1) - 15(3-1) = 30 ti-a bang dupe tb - 1,7.
Ddi ehidu vdi bang trong tii UOu ciia Le Cdng Huynh [3] thi tit c i cdc he sd ciia phuong ti-mh (9)
NONG NGHIfP VA PHAT TRIEN N 6 N G T H 6 N - KY 2 THANG 7/2011 93
KHOA Hpc CbNG NGHl ddu thda man didu kien t^ > tb, vdy chiing ddu cd y
nghia.
Kidm tra tinh tuong thich cua md h m h : F^ = 1.73 < Fb = 2,04 => md hinh toan hpc tuong thich.
Chuydn phirong trinh hdi quy tir dang ma sang dang thuc
Thay thd cac gia tri ma hda: Xj = (Xi -7,5)/2,5 = 0.4Xr 3; Xj = (X2 250)/50 = 0,02X2 - 5; X3 = (X3 10)/5 = 0,2X2 - 2 vao phuong hinh hdi quy (9) va thay cac ky hieu Xj bdng P, X2 bdng t va X3 bdng T. Sir dyng phan mem OPT tim ra phuong trinh dang thuc ciia ham ling suit nen vien nhu sau: o = 4,34 + 0,49P -
-„igpf||:
0,019P2 - 0,0089t - 0,000054tP + 0,0000019t2 + 0,01T -
0,0002TP - 0,00023Tt + 0,003T' (10) d. Xic dinh thdng sdedngnghS tdi uu
Sau khi yai ly kdt qua thi nghiem nhd phin mdm OPT, ta x i c dinh dupe g i i tii c i c thdng sd cdng nghe tdi uu nhu sau: P = 8,29 Mpa, t = 245°C v i T = 9,46 phiit Thay cac gia tri P, t v i T tdi uu vio phuong trinh (8) va (10) ta x i c dinh dupe gia tri ciia cac ham myc tieu la a = 4,47 Mpa va p = 0,37 g/cm\
Tidn h i n h chd tao vien nhien Ueu vdi cic thdng sd cdng nghe tdi uu nhu hinh 5.
fi'X 'y'A ''•Z
Huih 5. Vien nhien U^u dupe tao vdi thdng sd cdng nghe tdi uu
IV KET LUAN thdng sd dd l i co sd cho thidt kd thidt hi dp va phue vu cdng nghe sin x u i t vien nhien Ueu tir phd thai chd bidn gh mOt cich hidu qua n h a t
- Kdt q u i nghien cihi ly thuydt cho thay trong go cd ty le linhm chidm tir 17 - 30%, l i chat keo cd t i c dyng uen kdt cic td bao gd thanh khdi vung chdc v i nhiet do de cho Imhin trong gd ndng chay c i n
> 170° C Nhu vay ndu trong q u i trinh ep phd thai che bidn gd c i n dupe gia nhiet tdi nhiet dO c i n thidt cho linhm trong gd ndng chiy thi khdng phii trOn cac phu gia khac ma vin tao ra dupe khdi vung chic.
- Kdt qua nghien ciru thue nghidm don ydu td da xic djnh dupe quy luat va mirc dO anh hudng ciia timg ydu td cdng nghe cua q u i trinh dp nhu dp suit, nhiet do va thdi gian ep den chit luong ciia vien nhien Ueu dupe dinh g i i thdng qua khdi lupng the tich va do bdn eo hpc ciia vien. Kdt qua dat dupe cho thay sir anh hudng ciia cic ydu td dd ddn chit lupng vien nhien Ueu la dang kd va quan h e theo h i m sd bac hai.
Kdt qua nghien cuu thuc nghiem da ydu td da xdy dung dupe md hinh toan bidu didn su anh hudng ddng thdi cua c i c ydu td: i p suit ep, thdi gian dp, nhiet do dp vdi dO bdn co hpc v i khdi lupng thd tich ciia vien nhien Ueu. Tren eo sd c i c md hinh toin hpc tim dupe, ap dyng phirong p h i p tim cue t q ciia ham nhidu bidn de xac dinh ra c i c thdng sd cdng nghe tdi uu P = 8,29 Mpa, t = 245''C va T = 9,46 phiit C i c
TAI L P THAM KHAO
1. Nguydn Vdn Bi, 2006. Phuong phip nghi^ cuu thuc nghiSm. Tnrdng Dai hpc Lam nghiep. H i Tay, 7 - 35.
2. Hoing Nguydn Thu Ha, 2008. Nghiin cuu sin suit viin nhiin USu tirBIOMASS. Tuydn tap hOi nghj smh vien nghien cim khoa hpc. Trudng Dai hpc Da Ndng, Da Ning.
3. Le Cdng Huynh, 1995. Phuong phip nghiin cuu khoa hpc. NXB Nong nghidp. H i NOi, 6 3 - 9 9 .
4. Dao Quang Trieu, 1991. Phuong phip giai bii toin tdi uu tdng quit khi nghiSn ciiu dc qui trinh phue tap vdi sir ung dung quy hoach thiie nghiSm va vi tinh. Tuydn tdp cdng trinh nghien ciiu khoa hpc ky tiiudt ndng nghidp. Trudng Dai hpc Ndng nghidp l NXB Ndng nghidp. H i NOi, 23 - 56.
5. Le Xuan Tinh, 1998. Khoa hpegd. NXB Ndng nghidp. Ha NOi, 15 - 39.
6. http//www,FAO.Qrg/Introduetion 7. h t ^ / / w w w . agico.eom.cn
94 NONG NGHllP VA PHAT TRIEN NONG T H 6 N KY 2 - THANG 7/2011
KHOA HpC
C P N GNGHl
A STUDY ON DETERMINING OPTIMAL TECHNOLOGICAL PARAMETERS IN SAW DUST PELLET PROCESS
Le Van Thai, Phan Tiing Hung Summary
In Vietnam, waste generated from wood processing industries is about several hundred thousand tons yearly. Because of the shortage in professional treaments, huge amount of this waste is left untreated on soil surface which may cause environmental hazards and lead to a significant waste of natural energy as well. One of the best solutions for this challenge is to recycle the waste into a fiiel source called wood peUets. This will remarkably reduce the cost in transportation and store, cut down fossil fuel abuse, improve natural environment and reduce greenhouse gas. In order to create a background for improving technologies and equipment design in wood pellet process, optimal technological parameters of this process need to be determined. By theoretical and experimental studies, mathematical models describing individual as well as concurrent effects of different paramaters to the quality of the pellets based on mechanical strength and calorific energy criteria are established. Using Lagrange Multiplier method for finding extrema of multivariable functions, optimal technological parameters from these mathematical models are determined including pressure, temperature and compressed time.
Keywords: Lignin, experimental matrix, waste d-om wood processing, experimental planning, biomass, experiments with a single factor, experiments with more than one &ctor, optimal technological parameters.
Ngudi phin bi^n: PGS.TS. Trjnh Hftu L$p
N 6 N G
