co dac chanh day

7/29/2019 Co Dac Chanh Day

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n hc phn K Thut Thc Phm

GVHD: o Thanh Kh

MC LCCHNG I: TNG QUAN........................................................................................................2

1.1. NHIM V N.................................................................................................................2

1.2. NGUYNLIU CHANHDY .....................................................................................................3

1.2.1. nh danh 3

CHNG II. THIT K THIT B CHNH........................................................................252.1. CN BNG VT CHT V NNG LNG..................................................................25

2.1.1. CN BNG VT CHT 25

2.1.2. CN BNG NNG LNG: 26

2.2. TNH THIT B TRUYN NHIT......................................................................................322.2.1. H s truyn nhit 32

2.2.2. H s truyn nhit trong qu trnh gia nhit dung dch ban u t 30oC n 83.48oC 37

2.3. B MT TRUYN NHIT V THI GIAN C C.......................................................41

2.4. TNH THIT B C C.....................................................................................................43

2.4.1. ng knh 44

2.4.2. Chiu cao 46

2.4.3. Np 48

CHNG III: S NGUYN L V S .................................................................48THIT B CHNH.....................................................................................................................483.1. SNGUYNL..................................................................................................................48

3.1.1.S : 48

3.1.2. Hot ng ca h thng: 49

3.2. STHITBCHNH............................................................................................................50

3.2.1. S 50

3.2.2. Nguyn l hot ng 51

CHNG 4: KIM SOT V IU KHIN QU TRNH...............................................524.1. CC YU T NH HNG LN QU TRNH C C ..............................................52

4.4. CC THNG S CN KIM TRA:...................................................................................56

KT LUN.................................................................................................................................58TI LIU THAM KHO.........................................................................................................59

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GVHD: o Thanh Kh

CHNG I: TNG QUAN

1.1. NHIM V N

Thit k h thng thit b c c mt ni, vi cc thng s sau :

- Thit b c c mt ni, ni hai v, c cnh khuy.

- Nng sut sn phm: 1200 kg /m nc p chanh dy.

- Khi lng ring: 1050 kg/m3

- Nng sn phm : 40%.

- Dng hi nc bo ha c nhit ty chn.

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GVHD: o Thanh Kh

- Chn:

Thit b ngng t dng ng xon

Nng nhp liu: 14 %.

Cht ti nhit l nc nng, nhit cao nht ca cht ti nhit l 1000C.

p sut hi th thit b ngng t: pCK= 0,65 atm.

Nhim v chnh:

Tnh cn bng vt cht, cn bng nng lng.

Tnh thit b truyn nhit.

Tnh thit b chnh (ni c c).

V s nguyn l.

V s thit b chnh.

B qua tnh ton cc thit b ph.

1.2. Nguyn liu Chanh dy

1.2.1. nh danh

Tn khoa hc: Passiflora edulis Sims

H: Passifloraceae

Loi: Passiflora

Dng: Berry

Chanh dy thuc h Passifloracae v c h gn vi cy violet. C hn 500 loi

Passiflora, thuc h Passifloraceae, khong 50 trong s c th n c. Nhng ch mtloi duy nht, P. edulis Sims, mi c tn gi l Passion fruit. Trong loi ny, c hai dng

phn bit: dng ta (purple) thng thng v dng vng (yellow) khng ch mu

sc m cn mt s c im khc.

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GVHD: o Thanh Kh

Chanh dy vng l loi cy nhit i hay cn nhit i, c trng ch yu

Hawaii, Fiji, Kenya, Papua New Guinea, i loan, Brazil, Colombia, Nam Phi,

Venezuela v Florida.

Cc vng trng chanh dy ln nht gm: Hawaii, Fiji, Australia, Kenya, Nam Phi,

New Guinea v New Zealand.

S pht trin ca cy chanh dy Vit Nam

y l loi cy hoang di. Gn y, ngy cng c nhiu sn phm c ch bin t

loi qu ny, iu ny to thm mt ging cy trng mi cho b con nng dn. Lm

ng l vng t c kh hu v th nhng thch hp cho loi cy ny. Nhng nm gn

y, chanh dy c nhiu ngi bit n v c by bn nhiu cc ch thnh ph H

Ch Minh, H Ni Chanh dy rt d trng, cho nng sut cao.Tuy nhin mc ch s

dng ph bin vn l n ti, ch bin nc gii kht, nc siro c c, ch bin thnh

xt dng km vi cc mn n khc trong nh hng.

Hin ti, Vit Nam c hai loi chanh dy, mt loi c chit ghp vi ging ca

i Loan, mt loi thun Vit. Theo ng y, cc hp cht trong chanh dy c tnh hn,gip b dng cho tim mch, lu thng kh huyt, h thn nhit Vi cc c tnh trn,

chanh dy ngy cng c ch khai thc v nhn rng, hng ti canh tc theo quy m

cng nghip.

1.2.1.2. M t c im

c im thc vt hc

Cch pht trin: chanh dy l mt loi cy dy leo khe, c bit l nhng vngnhit i. Tua ca cy bm vo hu ht bt c ch no ca vt chng n. Hng nm,

cy c th mc ln t 4m n 6m. Ni chung, y l loi cy c i sng ngn (t 5 7

nm).

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GVHD: o Thanh Kh

L: mc xen k, c dng thy su 3 lp, c rng ca khi trng thnh. L di 7cm

20 cm, mt trn lng v c mu xanh m, mt di nht hn v m c.

Hoa: mc trn mi t, c dng n, c mi thm, rng 5cm 8cm, gm c 5 i

trng hi lc, 5 cnh trng, mu ta m y. Hoa c 5 nh c bao phn, c bu nhy,

vi nhy phn lm 3 nhnh to nn mt cu trc ni bt gia. Dng qu ta ra hoa vo

ma xun v u ma h (thng 7 - thng 11) v ra hoa ln na vo ma thu v u ma

ng (thng 2 - thng 4). Hoa n vo lc sng sm v tn trc bui tra, hoa c kh

nng t tng hp.

Hnh 1.2: Hnh dng v cu to hoa chanh dy

Qu chanh dy: c hnh dng hi trn hay hnh trng, ng knh khong t 1-1,5

n 3 inches, c bao bc bi mt lp v dy (khong 3mm), cng, nhn v c ph lp

phn mng, c mu t m vi cc m nh v m, cho n vng nht hay mu vng

nh b ng. Gn vi lp v ngoi l lp ci trng dy khong 6mm. Rut chanh dy rng,bn trong cha nhiu ti nh cu to bng mng membrane c hai lp vch ngn, bn

trong cha dch qu mu vng cam v khong 250 ht nh, cng, mu nu sm hay en.

Chanh dy c hng v rt c o: thm nng, chua rt thanh v ngt m. Thc ung

ch cn cha 5% nc ct chanh dy cng c mi rt mnh. Mi chanh dy l s ho

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GVHD: o Thanh Kh

quyn ca mt lot nhiu th mi tri cy khc nhau nh i, thm, xoi, u Chanh

dy c v gn ging nh du, o hay m.

Hnh 1.1: Chanh dy vng v chanh dy

Cch chn la v tch tr

Chn qu to, nng, chc. Khi chn, da qu teo li, c ch trng nhng khng c b

mm nhiu, qu c mu ta m. Sc da trng c v xu, nhng khng c ngha l qu b

h. Tuy t khng nh hng n cht lng qu nhng trc khi d tr, cn ra v lau

kh nh nhng. Gi qu vng cha chn hn 20 oC vi m tng i t 85 90%. 30 oC, qu s qu chn. Qu chn gi trong 1 tun 2,22 - 7,22 oC. ng qu trong ti

polyethylene kn, khng c l 23,1 oC s gi qu c 2 tun. Ph bn ngoi mt lp

parafin v gi 5 7 oC v m tng i t 85 90% s ngn hin tng qu b nhn

li v duy tr c cht lng qu trong 30 ngy.

1.2.1.3. Thnh phn dinh dng

Gn 84% dch qu chanh dy l nc, cn li l cc hp cht thm, cc hp chtmu, cc cht sinh nng lng (ng, tinh bt) v cc cht vi lng (khong,

viatmin). Cht bo v protein cha trong dch qu chanh dy khng ng k, ch chim

khong 3-4% tng nng lng cung cp. Chanh dy cha nhiu vitamin A, C, cc cht

khong nh K v Fe nhng li cung cp t nng lng, mi tri ch cho khong 16

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http://images.google.com.vn/imgres?imgurl=http://www.mitre10.co.nz/Image/info/143-PassfruitPurple.jpg&imgrefurl=http://www.mitre10.co.nz/how_to_guides/gardening/a_passion_for_passionfruit.cfm&h=173&w=180&sz=15&hl=vi&start=23&tbnid=8GZ6syRu2bV2DM:&tbnh=97&tbnw=101&prev=/images?q=%5C


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GVHD: o Thanh Kh

Bng 1.3: Hm lng ng ca 2 loi qu (% theo khi lng n c)

Loi chanh dy fructose glucose saccharoseQu ta 33,5 37,1 29,4

Qu vng 29,4 38,1 32,4

Tinh bt

Dch qu c hm lng tinh bt cao bt thng. Nc chanh dy p cha hm

lng tinh bt t 0,5 n hn 3%. Hm lng tinh bt ca chanh dy l 0,74%, cao

hn ca chanh dy vng 0,06%, trong amylose (ca c hai dng chanh dy) chim t

l khong 5,8 - 8,7%, cn li ch yu l amylose pectin. Kch thc ht tinh bt ca c

hai dng kh ging nhau (khong 4,0-12,2 m). Nhit ng c ca tinh bt (c hai

dng chanh dy) khong 58,5 67 oC, kh thp nn gy nh hng xu trong qu trnh

x l nhit dch qu do bm ln b mt thit b trao i nhit, gy nng cc b, nh

hng n hiu qu truyn nhit v lm gim cht lng hng chanh dy.

Cc acid hu c

Hm lng acid hu c cao cng l mt tnh cht c trng bn cnh mi v ca

chanh dy. Chnh lng acid hu c ny lm cho dch chanh dy c gi tr pH thp v v

chua rt gt.

Mt phm cht c bit ca chanh dy vng l hm lng acid citric cao. Ging nh

dch qu ca chanh, dch qu chanh dy c hm lng acid kh cao. Acid citric bao gm

tt c hm lng acid khng bay hi thay i t 93 - 96% tng lng acid, v acid malic

chim t 4 - 7%. Tc dng c ch cho c th ca acid citric c th l gip bo v, h tr

cho km v cc nguyn t vt khc.

Chanh dy vng c t acid ascorbic hn chanh dy nhng tng lng acid (ch

yu l acid citric) v hm lng carotene li nhiu hn.

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GVHD: o Thanh Kh

Cc acid amin t do trong dch qu chanh dy gm c: arginine, acid aspartic,

glycine, leucine, lysine, proline, threonine, tyrosine v valine.

Enzyme

Dch qu chanh dy vng c cha enzyme catalase, c th b v hot hon ton 79oC trong vng 75 giy.

Dch qu chanh dy c cha enzyme methylesterase, b v hot 80 oC trong 60

giy. Ngoi ra, cc nh khoa hc cn pht hin s c mt ca hai loi enzym protease

trong chanh dy , acid protease v SH-protease. S dng caseine lm c cht, pH ti

thch cho acid protease l 2,3 v cho SH-protease l 5,7.

Cc vitamin v nguyn t khong

Viatmin C

Tri chanh dy c bit giu vitamin C. Viatmin C tan tt trong nc v ng vai

tr ch yu l mt cht chng oxy ho. Vitamin C gip bo v phn m mm ca c th,

ng thi c kh nng bo v plasma lipids v LDL Cholesterol khi cc gc t do.Ngoi ra, viatmin C cn ng vai tr quan trng trong vic duy tr h min dch ca c

th v thm ch lm gim nh mt s triu chng cm lnh ngi. Mt ly nc chanh

dy p cung cp khong 50% lng vitamin C cn thit trong ngy cho mt ngi

trng thnh nam, i vi n l 60%. Nc chanh dy l ngun thc n cung cp vitamin

C cc k tt.

Vitamin A

Chanh dy cng cha rt nhiu vitamin A. Rt nhiu carotenoid c tm thy trong

chanh dy c hot vitamin A khc nhau. Vitamin A l loi vitamin tan trong du, cn

thit cho th lc, da, s pht trin v ti sinh m t bo. Mt ly nc ct chanh dy cung

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GVHD: o Thanh Kh

cp khong 6000 I.U vitamin A. iu ny chng t chanh dy l ngun thc phm rt

giu vitamin.

Cc loi vitamin khc

Nc ct chanh dy cn cha nhiu riboflavin, niacin v acid folic.

Cc cht khong

Chanh dy cn cung cp nhiu cht khong nh potassium (K), mt cht in li

quan trng trong vic h tr m co bp ca tim, n nh cn bng acid-base v huyt p.

Chanh dy l s thay th cc k tt cho cc loi thc n khc nh chui hay cam. Cc

chuyn gia dinh dng khuyn co n ng v ph n nn dng 1,6 - 2g potassium/ngy.

Mt tch nc chanh dy p cung cp khong 34 - 72% lng potassium nn dng ny.

Chanh dy cn cha 10 - 13% nhu cu hng ngy v magnesium (Mg), mt nguyn

t khong gip n nh huyt p.

Bng 1.6: Hm lng potassium cha trong cc loi tri cy thng thng

Cc loi tri cy Potassium (mg/100g)

Chanh dy 278Bi 127

Kiwi 332

Xoi 156

u 257

Da 113

Chui 396Cam 169

(Ngun t USDA Nutrient Data Laboratory)

Alkaloids v cc hp cht Cyanogenic

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GVHD: o Thanh Kh

C 7 loi alkaloid trong chanh dy, 4 trong s c xc nh v t tn l

harman (c ngha l iu ho), harmin, harmol v harmalin. Cc th nghim dc l cho

thy dch chanh dy c tc dng an thn nh. Hm lng alkaloids trong chanh dy l

0,012 %, chanh dy vng 0,700 % (ch yu l harman).

Cc hp cht d bay hi

Cc hp cht d bay hi chim thnh phn chnh l cc ester t C2-C8 ca cc acid

bo C2-C8 thng gp nhiu loi tri cy khc. Cc sn phm phn hu ca cc

carotenoid ( -ionone, dihydro--ionone), cc cu t cha S v cc ester bo him gp

ng vai tr rt quan trng trong vic to ra hng v c trng ca chanh dy.

Ngai ra, do s ho quyn ca nhiu loi ester c trng khc nhau ca nhiu loi

tri cy khc m tri chanh dy c hng v v cng c bit. V d cc ester ethyl (Z)-

octa-4,7-dienoate v (Z)-Hex-3 enyl butanoate l cc ester c trng ca da v l.

Sc t

Sc t chnh trong dch qu chanh dy l carotenoid. Nc chanh dy p cha rt

nhiu loi sc t vng v cam ny. Cho n nay, c khong 13 loi carotenoid c tm

thy trong dch qu chanh dy, gm -, -carotene, phytofluene, -apo-12-carotenal, -

apo-8-carotenal, cryptoxanthin, auroxanthin, mutatoxanthin...

Cc carotenoids, c bit l beta-carotene, gip con ngi bo v cc t bo khi s

ph hu ca cc gc t do v c th gip li s hnh thnh cc t bo tin ung th. Ch

n giu carotenoids cho thy mi quan h cht ch gia carotenoids vi vic gim nguy

c ung th v, hng, phi, da v ung th d dy. Hot tnh chng oxy ho ca cccarotenoids c th cng quan trng trong vic gim nguy c ca bnh tim mch v c

thy tinh th mt.

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GVHD: o Thanh Kh

Dch qu chanh dy khng cha anthocyanin, cn hm lng flavonoids trong

chanh dy rt b, ch dng vt, trong chanh dy l 1,060%, trong chanh dy vng l

1,000%.

Cc sterol thc vt

Cc sterol thc vt c tm thy trong tt c cc loi thc n c ngun gc thc vt

v c cc nh khoa hc cho l c kh nng lm h thp cholesterol mu. Tng tiu th

thc n thc vt cha lng sterol cao c th c tc ng tch cc cho sc kho, mc d

cc li ch c th cng tu thuc cc yu t khc trong thc vt nh hm lng cht

x ho tan c. Chanh dy cha tng hm lng sterol thc vt cao nht so vi cc loi

tri cy n c khc. So vi ci xanh, ci brussel, sp l v liu en, chanh dy l s

thay th tuyt vi cho cc loi rau giu sterol. Mc d chanh dy cha lng sterol thc

vt tng i cao, nhng c th thy c tc dng lm gim lng cholesterol th cn

phi dng mt lng nc p rt ln.

1.2.1.4. Gi tr s dng ca chanh dy

Trong cng nghip thc phm

Phn tht qu chanh dy c th c dng ch bin cc mn n trong gia nh. V

d Australia ngi ta dng tht qu chanh dy vi kem hoc ng, lm mn salad tri

cy, lm thc ung hoc lm gia v.

quy m cng nghip, dch qu chanh dy dng sn xut nc qu c, hoc

phi trn vi ng v pha long vi nc cng dch qu ca cc loi tri cy khc (c

bit l cam v da) sn xut cc loi thc ung lnh. Nam Phi, nc ct chanh dyc phi trn vi sa v alginate, Australia th c dng trong sn xut sa chua.

Trong y hc

Cc alkaloid trong dch qu chanh dy c chit xut bo ch thuc an thn,

gim au. Ngoi ra, mt loi glycoside chit xut t chanh dy (c bit l P.incarnata L.)

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GVHD: o Thanh Kh

gi l passiflorine cng c dng bo ch thuc gim au v an thn chu u. Cc

nh ho hc Italia chit xut passiflofrine t l chanh dy P. edulis sy kh.

Madeira, nc ct chanh dy c dng nh mt cht kch thch tiu ho cho cc

bnh nhn ung th d dy.

1.2.2. Quy trnh sn xut

1.2.2.1. S quy trnh cng ngh

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Chanhdy

Chn la

Ra

Lc th

Gia nhit

Bo qun

Thanh trng

Thnh phm

Qu h

B th

Ghp np

Li tm

Rt chai

C c

B

tinh

Chai

Np

V, ht

p


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GVHD: o Thanh Kh

+ Bin i tnh cht vt l: thi gian c c tng lm cho nng dung dch tng

dn n tnh cht dung dch thay i.

Cc i lng gim: h s dn nhit, nhit dung, h s truyn nhit, h s cp

nhit.

Cc i lng tng: khi lng ring, nht, nhit si, tn tht nhit do nng

.

+ Bin i tnh cht ha hc:

Thay i pH mi trng: thng l lm gim pH do cc phn ng phn hy amitca cc cu t to thnh cc acid.

ng cn d: do trong dung dch cha mt s mui Ca2+ t ha tan nng cao,

phn hy mui hu c to kt ta.

Phn hy cht c c.

Tng mu do caramen ha ng, phn hy ng kh, tc dng tng h gia cc

sn phm phn hy v cc amino acid.Phn hy mt s vitamin.

+ Bin i sinh hc:

Tiu dit vi sinh vt ( nhit cao).

Hn ch kh nng hot ng vi sinh vt nng cao.

1.2.2.2.7. Rt chai, ghp np

Dung dch chanh dy trong qu trnh bo qun v tn tr th hng v gim st r

rt. hn ch tnh trng ny ngi ta bo qun trong chai nha hoc thy tinh c

ghp np. Mt khc np chai phi c ghp tht kn v tht chc nhm m bo qu

trnh thanh trng khng b bt np hay h mi ghp.

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GVHD: o Thanh Kh

Nhm 1: dung dch i lu t nhin (tun hon t nhin) dng c c dung dch kh

long, nht thp, m bo s tun hon d dng qua b mt truyn nhit. Gm:

+ C bung t trong (ng trc bung bc), c th c

ng tun hon trong hoc ngoi.

+ C bung t ngoi (khng ng trc bung bc).

Nhm 2: dung dch i lu cng bc, dng bm to vn tc dung dch t 1.5-

3.5m/s ti b mt truyn nhit. C u im: tng cng h s truyn nhit, dng cho dung

dch c st, nht cao, gim bm cn, kt tinh trn b mt truyn nhit. Gm:

+ C bung t trong, ng tun hon ngoi.

+ C bung t ngoi, ng tun hon ngoi.

Nhm 3: dung dch chy thnh mng mng, chy mt ln trnh tip xc nhit lu

lm bin cht sn phm. c bit thch hp cho cc dung dch thc phm nh dung dch

nc tri cy, hoa qu p...Gm:

+ Mng dung dch chy ngc, c bung t trong hay ngoi: dung dch si to bt

kh v.

+ Mng dung dch chy xui, c bung t trong hay ngoi: dung dch si t to bt

v bt d v.

1.3.3.1.2. Theo phng php thc hin qu trnh

C c p sut thng (thit b h): c nhit si, p sut khng i. Thng dng

c c dung dch lin tc gi mc dung dch c nh t nng sut cc i v thi

gian c c l ngn nht. Tuy nhin nng dung dch t c l khng cao.

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GVHD: o Thanh Kh

1.3.3.3. Yu cu thit b v vn nng lng

- Khong khng gian dung dch c c cn nh nht, khng c khongkhng cht.

- Dung dch chanh dy lu li trong ni vi thi gian ngn nht.

- C h s truyn nhit ln .

- Hi t phi m bo phn b u trong khng gian bn ngoi gia cc ng

ca dn ng (m bo nhit phn b u cho cc ng ca dn ng).

- m bo thot kh khng ngng tt. V kh khng ngng phng t cn

thot ra bnh thng. S tn ti ca kh khng ngng trong phng t s lm gim h s

cp nhit ca hi v do gim nng sut bc hi.

- m bo thot nc ngng t d dng. Vic thot nc ngng t c lin

quan cht ch n tc bc hi.

- Thit b n gin, din tch t d lm sch.

Thao tc khng ch n gin, t ng ho d dng

1.3.4. La chn thit b c c:

1.3.4.1. La chn phng n c c:

Phng n c c p sut kh quyn c u im v nhc im sau:

- u im: thit b n gin d ch to, d vn

hnh thit b, chi ph vn hnh thp

- Nhc im: nhit si ca dung dch cao nn

sn phm d b bin tnh bin mu bin mi

Phng n c c p sut chn khng c u im v nhc im sau:

- u im: nhit si ca dung dch c

gim ti a nn sn phm hn ch b bin tnh, bin mu, bin mi

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GVHD: o Thanh Kh

CHNG II. THIT K THIT B

CHNH

2.1. CN BNG VT CHT V NNG LNG

2.1.1. CN BNG VT CHT

Cc s liu ban u:

Dung dch xir c:

- Nhit u 30oC, nng u 14% khi lng ng kh (ch s 14Bx)

- Nng cui 40% khi lng ng kh (ch s 40Bx)

Chn nhit ca nc trong v l 900C

p sut lm vic ca thit b c c l: P ck= 0,65 atm.

C c gin on vi nng sut 1200kg dung dch em c c/m.

2.1.1.1.Khi lng ring ca dung dch xi r theo nng

Nng

, %14

40

(kg/m3) 1050 1178,5

2.1.1.2. Cn bng vt cht cho cc giai onG = Gc + W

G.x = Gc.xc

Trong

G , Gc : lng dung dch u v cui, kg

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2.1.2.1. Cc tn tht nhit Nhit si dung dch

Ta c tn tht nhit si theo nng dung dch si r p sut kh quyn (s tay

QTTB tp 2). T suy ra nhit si dung dch sir p sut kh quyn theo cc nng

l:

Nng dung dch,

%14 40

' Pa, oC 1 1,5

Nhit si dung

dch Pa, oC103 106,5

2.1.2.2. Xc nh tn tht nhit do nng v nhit si dung dchxi r theo

nng p sut P1 = 0.35 atm

Theo phng php Babo

22

12 t

OH

dd

tOH

dd

PP

PP

=

* Xt dung dch xi r 14%

Nhit dung dchxi r 14% Pa = 1.033 at l 110oC

110oC p sut hi nc bo ha l 1.461 at

Ta cn xc nh nhit si dung dch P1 = 0.3636 at

110OH

dd

tOH

dd

22PP

PP

=

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GVHD: o Thanh Kh

dm : Khi lng ring dung mi tsdm

Chiu cao v o trn thn thit b truyn nhit Ho = 300mm

Tnh cho trng hp dung dch xi r 14%

Do trong khong nhit nh, hiu s dmdd thay i khng ng k nn ta chn

tra dmdd, 30oC3/995 mkgdm =

3

%)14(dd m/kg1050=

[ ] 1011.03,0*)9951050(*0014.026.0H op =+= m

at00265.0m/N34.2601011.0*81.9*1050*2

1*5.0H*g**5.0P 2ophh ====

at36625.000265.03636.0PPP 1tb =+=+=

Nhit si ca H2O 0.36625 at l 74.998oC 75 oC

tng nhit si do ct thy tnh

C95.105.7375tt 0)P(sdm)P(sdm''

1tb===

nhit si dung dch xir 14% p sut P1+ P

C49.8395.154.81t 0)PP(sdd 1 =+=+

Tnh tng t ta c

Nng dung dch, % 14 40'' , oC 1.95 1.95

)PP(sdd 1t

+ 83.49 85.38

2.1.2.4. Cn bng nng lng cho cc giai onTa c:

* Phng trnh cn bng nhit

ctwcccnnnD QQcDiWtcGtcGiDcD +++=++ ......).1.(...''

.

''

Vi

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GVHD: o Thanh Kh

tD =100oC

* Nhit ha hi ca nc p sut 1 atm

r = 2171.103 J/kg (s tay QTTB tp 1)

* Entanpi ca hi th 73.05oC''wi =2632.2*103 J/kg (s tay QTTB tp 1)

* Tn tht nhit: Qt = 0.10*QD

* Tn tht nhit c c: Qcd = 0.10*QD

A. Giai on a dung dch 14% t 25oC n 83.48oC

G = Gc = 1200 kgc = cc =3376.5 J/kg

t = 30oC ; tc =83.49oC ; W = 0 kg

Nhit lng tiu tn cho qu trnh

Q1 =1200*3376.5*(83.49-30) =216.73*106 J

Nhit lng cn cung cp ( k c tn tht )

QD1 = J10*22895.0

Q 61 =

Tn tht nhit:

Qt1=0.10*QD = 0.10* 228*106= 228*105 J.

Tn tht nhit c c:

Qcd1 = 0.10*QD= Qt= 228*105 J.

B. Giai on a dung dch t 14% n 40%

G = 1200 kg ; c =3376.5 J/kg ; t =83.49oC

Gc = 420kg ; cc = 3213.8 J/kg ; tc = 85.38oC

W = 780 kg

Nhit lng tiu tn cho qu trnh:

Q2 = 420*3213.8*85.38 1200*3376.5*83.49 + 780*2632.2*103

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GVHD: o Thanh Kh

tdd : nhit dung dch si, oC

1vD1ttt =

ddv2 ttt 2 =

21 vvvttt =

( )1vDm

tt2

1t += : nhit mng nc ngng, oC

A. Pha nc si bc hi bo ha

111 t.q = (1)

Theo cng thc4

11 H*t

r*A*04.2

= (2)

Vi A=25.0

32.

ph thuc vo nhit tm

tm , oC 40 60 80 100 120 140 160 180 200

A 139 155 169 179 188 194 197 199 199

: khi lng ring ca nc nhit tm, kg/m3

: h s cp nhit ca nc nhit tm, W/mK

: nht ca nc nhit tm, Pas

r : n nhit ngng t ca hi nhit tD

r = 2171*103 J/kg

H = 0,3 m: chiu cao vch truyn nhit pha v o

B. Pha dung dch

q2 = 22 t. (3)

Theo cng thc435.0

dd

n

n

dd

2

n

dd

565.0

n

ddn2 .c

c...

=

(4)

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GVHD: o Thanh Kh

4. Tnh vt theo cng thc (6) vi qv = q1 2vt,t

2

5. Tnh n

theo cng thc (5) vi q = q16. Tnh 2 theo cng thc (4)

7. Tnh q2 theo cng thc (3)

8. Tnh qtb = ( )21 qq.21

+

9. Xc nh sai s ss =1

tb1

q

qq

Nu ss > 5% th chn li 1vt v lp li qu trnh tnh n khi t sai s nh

11. Tnh K theo cng thc (7)

2.2.1.2. Tnh K cho cc giai on

A. Tmh nng 14%

Chn

K2.5t7.127t 1v1 ==

Tnh 1

( ) 09.191AC3.1307.1279.132*21t om ==+=

8.89535.1*2.5

10*2171*09.191*04.2

H*tr

*A*04.2 43

4

11 === W/m2K

2

111 m/W968.465592.5*84.8953t.q ===

C6.2810*143.6*968.46559r.qto4

v1v ===

C1.996.287.127t ov2 ==

C62.1548.831.99t o2 ==

21.499616.35669*968.46559*56.0p*q*56.0 15.07.015.07.01n === W/m2K

435.0

3

32565.0

210*31.1

10*38619.0*

44.4189

5.3376*

97.975

1239

66983.0

577.0*21.4996

=

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GVHD: o Thanh Kh

A. Pha nc si bc hi bo ha

111

t.q

=

4

11 H*t

r*A*04.2

=

A xc nh theo tm

r = 2171*103 J/kg

H = 1.5 m

B. Pha vch

=

v

vv r

tq

= 124v )Km/W(10*143.6r

C. Pha dung dch

222 t.q =

l

.Nul.Nu dd2

dd

2

==

Trong

( )nPr.Gr.CNu=

dd

dddd.cPr

=

2dd

2dd3dd g.t...lGr

=

C v n ph thuc vo Pr v Gr nh sau:1. Gr.Pr 310 th Nu = 0.5

2. Gr.Pr 50103 = th ( ) 125.0Pr.Gr18.1Nu=

3. 710.2500Pr.Gr = th ( ) 25.0Pr.Gr54.0Nu=

4. Gr.Pr 710.2> th ( ) 33.0Pr.Gr135.0Nu=

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GVHD: o Thanh Kh

l: chiu cao v o truyn nhit, l = 0,3 m

dddddddddd c,,,, : khi lng ring ( kg/m3 ), h s dn n th tch ( K-1 ), h

s dn nhit ( W/mK ), nht ( Pa.s ), nhit dung ring ( J/kg ) ca dung dch

xi r ly nhit mng

+=

2vdd

_

m tt21

t

Vi Ct odd 24.54)3048.83(2

1_ =+=

3dd m/kg1239=

cdd = 3376.5 J/kg

3dd 10*31.1

= Ns/m2

mK/W577.0dd =

ca dung dch xi r 14%

To ,oC 0 20 40 60 80 100 120310. 0.425 0.455 0.48 0.505 0.535 0.57 0.605

D. H s truyn nhit

++=

2v

1

1r

11

K

, W/m2K

* Trnh t tnh lp

(1). Chn 1v tt 1

(2). Tnh 1

(3). Tnh q1

(4). Tnh 2v1 ttt 2

(5). Tnh Nu2 2

(6). Tnh q2

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GVHD: o Thanh Kh

(7). Tnh qtb = ( )21 qq21

+

(8). Tnh ss =q

qq tb1 , tnh cho n sai s nh (v phi nh hn 5% )

E. Thc hin tnh lp

(1). Chn C3.121t ov1 =

K6.113.1219.132t1 ==

tm= ( ) C1.1273.1219.1322

1 o=+ 13.190A =

(2). Km/W68.72895.1*6.11

10*217113.190*04.2 24

3

1 ==

(3). 2111 m/W29.845606.11*68.7289tq ===

(4). === K95.5110*143.6*29.84560r.qt 4v1v

C35.6995.513.121t ov2 ==

K11.1524.5435.69t2 ==

(5). Tnh 2

67.7577.0

10*31.1*5.3376.cPr

3

dd

dddd ===

( ) 50.0C795.6135.6924.5421

t o'm ==+=

( )14

23

23

10*273.210*31.1

81.9*11.15*508.0*1239*5.1Gr ==

ta thy Gr.Pr > 2.107

99.14454)Gr(Pr**135.0Nu

33.0

==

35.5560l

.Nu dd2 ==

W/m2K

(6). 2222 m/W89.84016t.q ==

(7). qtb = 84288.59W/m2

Trang 40


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GVHD: o Thanh Kh

(8). ss=0.003=0.3% (tho)

Vy h s truyn nhit giai on ny

Km/W74.1073

35.55601

10*143.668.7289

11

K 24

=++

=

2.3. B MT TRUYN NHIT V THI GIAN C C

Phng trnh truyn nhit cho khong thi gian nh dT

dQ= K.F(T-t).dT

Gi s n cui qu trnh dung dch vn ngp ht b mt truyn nhitF

khngi, T khng i

d.F T= ( )tTKdQ

Ly tch phn ta c

F.T2 = ( ) Q

0tTK

dQ(1)

T2 : thi gian c c ( khng k thi gian gia nhit cho dung dch u n

83.48oC ), s

Q : nhit lng tiu tn cho qu trnh ny, J

* Ta tnh tch phn (1) bng th. Cn xc nh Q, ( )tTK1

tng thi im.

Nng dung dch, % 14 40

Q.10-8, J 0 11.94

t(tsdd), oC 83.49 85.38

K, W/m2K 946.44 911.8

T-t 49.42 47.53

510*)tT.(K

1

2.1 2.3

V th c : trc honh : Q

Trang 41


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810.Q


GVHD: o Thanh Kh

: trc tung : ( )tT.K1

othxac nh thi gian coac vabemat truyen nhiet

0

1

2

3

4

0 5 10 15 20 25 30

Tng qu trnh c c t 14% n 40%

S = F. T = 67306 m2

.s* Chn thi gian c c l 40 pht

B mt trao i nhit l: F = 67306 / 2400 = 28.04 m2

Thi gian: T1 = 26268 / 28.04 = 936.8 s

* Thi gian gia nhit ban u

.F.t.KQ = T

T =F.t.K

Q

Vi Q : nhit lng dng cho gia nhit, J

K : h s truyn nhit cho qu trnh gia nhit, W/m2K

t : chnh lch nhit , K

Trang 42

510.)tT(K

1


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GVHD: o Thanh Kh

( ) ( )Kt 89.74

48.839.132

259.132ln

48.839.132259.132=

=

T = phts 5.4425.27104.28*89.74*74.1073

10*12.6 8=

* Chn thi gian nhp liu 15 pht

Thi gian tho sn phm 15 pht

* Tng thi gian c c 1 m l

Tt = 15 + 4.5 + 40 + 15 = 74.5 pht

Ta chn tng thi gian c c l 75 pht

2.4. TNH THIT B C C

Bung t v o:

ng knh ni c c: dn=250mm

ng knh v o: Dva=320mm

Chiu cao truyn nhit ca v o : h=300mm.

Din tch b mt truyn nhit : F = 0,25 m2

Ta ly an ton : F = 0,3 m2 ( 20%)

Chiu cao vch truyn nhit : H = 0,3

Kim tra iu kin : tit din ngang bung t v o > 0.25 tit din ngang ca ni c

c :

25.0

4

)(4

2

22

=

d

dD

S

S

o

th

(tha)

y

Chn y elip tiu chun c g

Tra s tay QTTB 2 ta c

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GVHD: o Thanh Kh

4

2

)(bbtr

hhi

D

V

=

2

)(.

7438.3*4

bbtr

hiD

=

Vn tc lng

Xc nh theo cng thc:

( )

h

lhlo

..3

d..g.4

=

Trong

l : khi lng ring git lng, kg/m3

h : khi lng ring hi th, h = 0.2224 kg/m3

dl : ng knh git lng, dl = 0.3 mm = 3*10-4 m

: h s tr lc

Ta c

l= 976.57 kg/m3, tra nhit 72.05oC

tnh theo Re

h

hh .d.Re

=

Vi h =0.0106*10-3 Pa.s : nht ng lc hc ca hi th

Gi s 0.2< Re < 500

Trang 45

2.1

)bb(tr6.0

2

)bb(tr

6.0D*0788.3

D

86.19

5.18

Re

5.18=

==


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GVHD: o Thanh Kh

Sau khi nhp liu 1200kg nguyn liu, qu trnh c c s bt u xy ra di

p sut chn khng do bm chn khng to ra.

Hi t theo ng dn a vo bung t. Hi th ngng t theo ng dn nc

ngng qua by hi chy ra ngoi v phn kh khng ngng c x ra ngoi theo ca x

kh khng ngng.

Hi th bc ln theo ng dn vo thit b ngng t Baromet, ngng t thnh lng

chy ra ngoi bn cha, phn khng ngng qua b phn tch git ch cn kh theo

bm chn khng ra ngoi.

Ton b h thng (thit b ngng t Baromet, thit b c c ) lm vic iu kin

chn khng do bm chn khng to ra.

Sau thi gian c c tnh, dung dch ng c bm ra ngoi theo ng tho sn

phm nh bm ly tm, vo thng cha sn phm.

3.2. S thit b chnh

3.2.1. S

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GVHD: o Thanh Kh

3.2.2. Nguyn l hot ng

Nguyn liu c nhp liu vo truyn nhit n nhit si ri mi cho vo ni c

c s trao i nhit vi hi thng qua cc ng truyn nhit s tr nn nh hn v c

tun hon tr ln pha bung bc. Ti y, hi nc c tch ra khi dung dch, dung

dch i theo ng tun hon trung tm xung y thit b v theo ng nhit tr ln trn.

Qu trnh trao i nhit c thc hin ch yu trong ng truyn nhit.

Sau nhiu ln nh vy, hi nc tch khi dung dch cng nhiu nng dung dch

cng tng, nht dung dch tng. Do , tc chuyn ng dung dch cng chm li

v sau. Qu trnh kt thc khi dung dch t c nng theo yu cu.

Tc chuyn ng tun hon cng tng th h s cp nhit v pha dung dch cng

tng, qu trnh bc hi xy ra cng mnh m, nng cht tan cng nhanh chng t yu

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GVHD: o Thanh Kh

cu v ngc li. Tuy nhin s hao ph nng lng khuy. Do , ta dng bin php khc

l tng ng knh ng truyn nhit.

CHNG 4: KIM SOT V IU

KHIN QU TRNH

Mc tiu iu khin qu trnh c c l sn phm thu c phi t nng , nng

sut theo yu cu ng thi, phi m bo c cn bng vt cht v nhit lng.

t c mc tiu trn ta phi kho st ton b h thng c c, xc nh cc

thng s cn kim tra v iu chnh, xc nh cc yu t nhiu cng nh la chn cc i

lng cn iu chnh, cc tc ng iu chnh, la chn cc thit b iu khin v kim

tra.

4.1. CC YU T NH HNG LN QU TRNH C C

Tc ng nhiu cho php n nh :

Lu lng, nhit dng nhp liu:G, t

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GVHD: o Thanh Kh

Nhit cht ti nhit: tD

y l cc yu t ta c th kim sot c chng, c th n nh c chng.

i vi dng nhp liu cc thng s c bn lu lng, nng , nhit s c

nh hng n cht lng dng thnh phm, cng nh nh hng n din bin ca qu

trnh c c.

nh hng ca dng nhp liu:

Nu nhp liu ng nh tnh l 10 lt /m v cc yu t khc u n nh th qu

trnh c c xy ra ng nh ta d on, cht lng dng thnh phm c bo m

nhng nu:Nh hn 10 lt /m (trong khong cho php): qu trnh c c xy ra nhanh, c th

khng dung dch cho qu trnh cp nhit ca nc nng, iu ny c th nh hng s

si trong ni, hi bc ln nhiu, nh hng n chn khng, nh hng n cht

lng sn phm.

Ln hn 10 lt /m (trong khong cho php) : lc ny lng nhit do nc nng

cung cp s khng lm bay hi dung mi, nng dng thnh phm khng t,

gim khong khng gian bc hi, nh hng n qu trnh bc hi, qu trnh c c dinra chm.

nh hng ca p sut lm vic thit b c c:

Nu p sut lm vic ca thit b thp tc nhit hi th thp dn n tc bc

hi ln. Trong trng hp mt chn khng do thit b r khng kh vo dn n nhit

dung dch cao, thi gian c c di, qu trnh c c km hiu qu.

nh hng ca nhit cht ti nhit:

Nhit cht ti nhit thp hn tnh ton nhit cp vo dung dch khng , tc

c c khng m bo.

Nhit cht ti nhit cao hn tnh ton nhit cp vo dung dch tha, dung dch si

mnh, c th xy ra s c dung dch si ln bt nh hng qu trnh c c.

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GVHD: o Thanh Kh

C nhiu i lng c trng cho mc ch iu khin, ta khng th no p ng ht

cc i lng cho nn phi tm cc thng s, i lng no ca qu trnh c c c

ngha quan trng nh hng trc tip n mc ch iu khin, v tm cch iu chnh

chng. Ta gi cc i lng ny l i lng cn iu chnh.V t mc tiu iu

khin ca qu trnh c c ta c th xt cc i lng sau:

Nng sn phm:xc

p sut trong ni: P

Lng nhp liu

Mc dung dch trong ni Nhit dng nhp liu vo ni c c: t

Xt nng sn phm :

Nng sn phm chnh l nng m ta mun dung dch phi t sau qu trnh c

c, v ta cng mong mun nng ny n nh trong sut qu trnh, nu c s xo trn

nng ny th cht lng sn phm s khng t yu cu cho cc cng on sau.

Xt p sut trong ni :

Qu trnh c c tin hnh vi p sut ni cui cng l p sut chn khng, mc

ch l gim nhit bc hi trnh nh hng cht lng sn phm . Do dung dch

ng khng chu nh hng nhiu t thng s nhit cho nn mc ch ny l quan

trng. D c tin hnh trong iu kin no th p sut trong ni cng phi c n nh v

n c nh hng n nhit bc hi, nh hng n kh nng tch dung mi ca dung

dch.

Nu p sut qu thp (chn khng cao), im si cng thp, p sut hi cng ln,

dung dch ng si cng mnh. Nhng nu chn khng cao hn na, nht ln nh

hng n i luv truyn nhit.

Nu p sut qu cao (chn khng thp ) th kh nng bc hi ca dung mi s gim,

nh hng n nng sn phm

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GVHD: o Thanh Kh

3 p sut hi th trong ni Lu lng nc lnh vo TBNT

Dng c o v iu khin:

o p sut bng p k bin dng loi hp xp kiu xiphng v y l loi p k c

cu trc n gin v tin cy, kch thc nh, d c, chnh xc cao v c khong o cao,

c s dng nhiu o v ghi li p sut v chn khng.

o nng sn phm ta dng chit quang k cm tay

o nhit ta dng nhit k ng h v nhit k in t lm vic trn nguyn tc

cp nhit in v y cn chnh xc cao.

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GVHD: o Thanh Kh

KT LUN

H thng c c c thit k gm ni c c v thit b ngng t ng xon kh

n gin, khng phc tp, khng cn thit b gia nhit ban u. Thi gian c c tng

i ngn, h s truyn nhit t c trong qu trnh c c l kh cao.

Thit b tng i nh gn, gi thnh khng qu cao c th chp nhn c.

Tuy nhin ta kh c th iu khin c qu trnh c c v thi gian c c c

th thay i khng n nh, nng t c l khng cao.

Qu trnh c c l qu trnh cn thit trong cng ngh ha cht v thc phm nncn c nghin cu pht trin c c hiu qu c c cao, chi ph thp.

Do kin thc cn hn ch, thi gian c hn nn chng em tnh ton khng khi

thiu st nn knh mong Thy ch dy thm. Chn thnh cm n.

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GVHD: o Thanh Kh

TI LIU THAM KHO

[1] Cc tc gi, S tay Qu trnh v thit b Cng ngh ho cht, Tp 1, NXB Khoa

hc v K thut, 1992

[2] Cc tc gi, S tay Qu trnh v thit b Cng ngh ho cht, Tp 2, NXB Khoa

hc v K thut, 1992

[3] Phm Vn Bn (ch bin) Nguyn nh Th, Gio trnh QT & TB CNHH tp

5 : Qu trnh v thit b truyn nhit, NXB H Quc gia TP HCM, 2002

[4] Phm Vn Bn V B Minh Hong Minh Nam, QT & TB CNHH tp 10 : Vd v Bi tp, Trng H Bch Khoa TP HCM

[5] Phm Vn Bn, QT & TB CNHH tp 11 : Hng dn n mn hc, Trng H

Bch Khoa TP HCM, 1993

[6] Trn Hng Dng Nguyn Vn Lc Hong Minh Nam V B Minh, QT &

TB CNHH tp 1, quyn 2 : Phn ring bng kh ng, lc ly tm, Bm, qut, my nn,

Tnh h thng ng ng, NXB H Quc gia TP HCM, 1997

[7] H L Vin, Thit k tnh ton cc chi tit thit b ha cht, NXB Khoa hc v K

thut, 1978

[8] Hong nh Tn, Truyn nhit & Tnh ton thit b trao i nhit, Trng H Bch

Khoa TP HCM, 1996

[9] Nguyn Vn La, QT & TB CNHH tp 1, quyn 1: Khuy Lng Lc, NXB H

Quc gia TP HCM, 2002

[10] Tp th Tc gi B mn My v Thit b Khoa Cng ngh Ho hc v Du kh

Trng i hc Bch Khoa i hc Quc gia Tp. H Ch Minh, Ti liu hng dn

Thit k An Mn hc Qu trnh & Thit b.

[11]. Phm Vn Bn Nguyn nh Th, Qu trnh v Thit b CNHH & TP Tp 5 :

Qu trnh v Thit b Truyn nhit. Nh xut bn i hc Quc gia Tp. H Ch Minh.

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GVHD: o Thanh Kh

[12]. Tp th Tc gi. S tay Qu trnh v Thit b Cng Ngh Ho Cht Tp 1&2 ,

Nh xut bn Khoa hc v K thut H Ni, 2004.

[13]. Phm Vn Bn. S tay dn nhit khng n nh Thng s nhit l ca Thc

phm v Nguyn liu.

[14]. Phm Vn Bn, Qu trnh v Thit b Cng ngh Ho hc v Thc phm Tp 5,

quyn 2 Truyn Nhit khng n nh , Nh xut bn i hc Quc gia Tp. H Ch

Minh, 2004.

[15]. Phm Vn Bn, Qu trnh v Thit b Cng ngh Ho hc v Thc phm Bi

tp Truyn Nhit, Nh xut bn i hc Quc gia Tp. H Ch Minh, 2004.

co dac chanh day

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