TAP CHi KHOA HOC VA CONG NGHE Tap 47, so 6, 2009 Tr. 41-45<br />
<br />
<br />
<br />
TINH TOAN THIET KE THIET B\ P H A N U'NG CHUYEN HOA<br />
THAN G A O D U A B A N G H Q I NUOC<br />
<br />
PHAM NGOC ANH, N G U Y E N TRUNG DUNG, NGUYEN CONG BANG,<br />
NGUYEN TRUNG T H A N H , MAI X U A N KY<br />
<br />
l.DATVANDE<br />
<br />
Than boat tinh la chat hap phu truyen thong da dugc sti' dung tir lau ddi. Cac nguon nguyen<br />
lieu de san xuat than boat tfnh la tat ca cac loai vat lieu chu'a cacbon, trong do dang ke nhat la<br />
cac phe thai thuc vat. Tii' nam 1911, Strejko [1] da dua ra cong nghe va he thong thiet bj cong<br />
nghiep chuyen hoa than go bang hai nudc san xuat than boat tinh tay mau. Thiet bj san xuat ctia<br />
Strejko la tien than ctia c6ng ty san xuat than boat tinh kh6ng 16 NORIT ngay nay [1]. Than hoat<br />
tfnh dimg de tay mau cac ban san pham c6ng nghiep nhu dung djch duong, dung djch bpt ngpt,<br />
dau thuc vat, dau khoang,...va dae biet la tir thap ki 50 cua the ki trudc trd di, than boat tinh la<br />
chat hap phu khong the canh tranh trong ky thuat lam sach nudc u6ng. Lupng than hoat tinh<br />
diing cho Ipc nudc uong hang nam len den hang train ngan tan [2], trong do uu viet nhat la than<br />
hoat tinh dupc san xuat tii' gao dtra vdi be mat rieng Idn, khong he dua chat la vao nudc va dae<br />
biet la dp ben ca hpc rat cao (> 98%) [3] nen co the tai sinh dugc rat nhieu lan [4,5], tren ca sd<br />
do giam dupc dang ke gia thanh str dung than boat tinh trong ky thuat lam sach nude u6ng.<br />
Viet Nam co mpt ngu6n nguyen lieu phong phti de san xuat than boat tinh: cac loai phe thai<br />
n6ng, lam nghiep, cac loai than khoang,... dae biet co nguon than gao diia hang tram ngan tan/<br />
nam nhung cho den nay viec nghien cu'u san xuat than boat tfnh gao dira con rat nhieu han che.<br />
Tinh Tra Vinh nhap thiet bi 16 dung san xuat than boat tinh gao dira ttr Trung Qu6c vdi nang suat<br />
thap, hieu suat khong cao va t6n nang lugng. Tinh Ben Tre nhap thiet bj 16 quay ctia Han QuIc<br />
nhung hieu qua san xuat kh6ng cao, chat lupng san pham kem, hieu suat thap.<br />
De gop phan vao viec thtic day san xuat than boat tinh va dae biet vdi mong mu6n Viet<br />
Nam se trd thanh mpt qu6c gia co danh tieng trong san xuat than boat tinh Ipc nudc tii' gao dira,<br />
bai bao nay trinh bay bai toan va ket qua tfnh toan, thiet ke thiet bj chuyen hoa than gao dii'a, san<br />
xuat than hoat tinh d quy m6 cong nghiep vdi nang suat 1500 tan san pham /nam.<br />
<br />
<br />
2. CO SO CUA TINH TOAN THIET KE<br />
<br />
Ca sd khoa hpc ctia bai toan tinh toan thiet ke mpi thiet bj phan trng hoa hpc la d6ng hpc<br />
ctia qua trinh chuyen hoa hoa hpc. Cac tinh toan trinh bay trong bai bao nay dua tren ca sd ket<br />
qua cac nghien ctru da thu dugc:<br />
Trudc het, m6 ta dpng hpc cua qua trinh phan u'ng da dupc nghien ctiu bang thuc nghiem<br />
va da thiet lap dugc bieu thuc toan m6 ta dpng hpc cua qua trinh [6, 7]:<br />
<br />
<br />
„ „ ( 96792^^ 0,5. .,.<br />
K.ff = 72.expi -—^\-CH,P (')<br />
<br />
<br />
41<br />
trong d6: R \h van toe hieu dung chuyen hoa cacbon trong than gao dira tinh tren mpt don \'j<br />
kh6i lupng cacbon dem phan trng, [molC/gc-pbtit]; C„ „ la nong dp ctia hoi nudc trong kh6ng<br />
gian phan u'ng.<br />
<br />
T".H,0 mol<br />
C„<br />
Fv<br />
<br />
Vdi: ^iH^O la lupng hai nude cap vao 16, lugng nudc sinh ra do cac phan trng chay nhien lieu,<br />
chay chat b6c trong kh6ng gian phan tmg, (mol/h); V^ la tong the tfch khf trong khong gian<br />
phan U'ng, (m Ih).<br />
Mat khac, cac nghien cu'u phan ung chuyen boa than gao dtra da dupc tien hanh trong<br />
phong thi nghiem deu thu dupc cac san pham than boat tfnh gao dtra co be mat rieng theo BET<br />
> 1000 m"/g, chi s6 lod > 1000 mg/g vdi hieu suat thu h6i san pham den 65% - 70% so vdi<br />
lugng cacbon da dua vao chuyen hoa [ 4 - 6 ] . Nhu vay de dam bao chat lugng than boat tfnh va<br />
hieu suat thu hoi san pham thi dp chuyen hoa cacbon trong thiet bj phan u'ng phai dat tii':<br />
20%-30%.<br />
De giai quyet van de tinh toan thiet ke, phai thiet lap va giai phuong trinh can bang chat<br />
cho cau tti' cacbon tuong ung vdi cau trtic d6ng ctia thiet bj phan ung da lira chpn [9]. Lap va giai<br />
phuong trinh can bang nhiet, tfnh toan va ket cau cac ca cau trao d6i nhiet, xac dinh tieu hao<br />
nang lupng can thiet cho qua trinh. Tren ca sd ket qua giai phuong trinh can bang chat va can<br />
bang nhiet, xac djnh dupc quy in6 va cac dae trung c6ng nghe ctia thiet bj phan u'ng cin phai<br />
thiet ke.<br />
<br />
<br />
3. KET QUA TINH TOAN VA THAO LUAN<br />
<br />
Thiet bj phan trng boat hoa than gao dii'a san xuat than boat tfnh dupc diing trong cong<br />
nghiep la loai 16 quay, d day than gao dira va dong khf tac nhan boat hoa (hai nudc) di ciing<br />
chilu va do do huong di chuyen cua than (clu tu phan ting chfnh) - chi di chuyin theo chieu<br />
true.<br />
De tfnh toan thilt bj phan irng ta str dung phuang trinh can bing chit trong he tpa dp<br />
tru. Gpi p^. la mat dp ctia cau ttr cacbon trong viing phan u'ng ta co [9]:<br />
<br />
d{p^..w^) _^d{p^..cdj<br />
+ yv,. .r .M,.<br />
dt dz dR oz' dR' R dR Z_i (j J (<br />
<br />
<br />
<br />
Khi qua trinh dat trang thai on djnh ^/f-^Q<br />
dp.<br />
va nhu da trinh bay d tren vat lieu rin<br />
dt<br />
(than gao dira) tham gia phan img chi djch chuyin theo chilu true cho nen phai co:<br />
<br />
'• • " '^ - 0 , dong thdi trong thilt bi cac phin tti' chit rin (than gao dtra) kh6ng bi khuly trpn<br />
dR<br />
ngupc theo chieu true va cung khong co hieu ung khuyeeh tan theo hudng ban kinh, cho nen:<br />
<br />
<br />
<br />
<br />
42<br />
D^.^^^O va n = 0-<br />
' dz- dR' R' dR<br />
Xem trong he chi c6 mpt phan u'ng hoa hpc:<br />
C + H2O -> CO + H, (2)<br />
nen ta co van toe chuyen hoa cau tu' cacbon la:<br />
<br />
Z^,.r = -Rr- (3)<br />
Mat khac ciing phai nhan thay rang, d cac he dj the phan irng chi xay ra trong npi bp cac<br />
phan tir pha ran va van toe chuyen hoa in6i cau ttr phai la van t6c chuyen hoa hieu dung [9]. Nhu<br />
tren, vdi Rceif [6,7,8] la van t6c chuyen hoa hieu dung ciia he cacbon [molC/gc.phiit] ta co:<br />
d{p,.coJ<br />
-Rcff-Pc-Mc (4)<br />
dz<br />
a dpc<br />
dz (5)<br />
R,,..M^. /?,<br />
<br />
<br />
Ket qua nghien ctiu dpng hpc ctia phan ung (2) da cho ket qua [6,7]:<br />
<br />
R =72.exp<br />
96792<br />
RT<br />
1.j C.<br />
molC<br />
g,..phiil<br />
(6)<br />
<br />
va lugng hai nudc cap vao 16 la rat du so vdi yeu cau phan u'ng, cho nen khi qua trinh phan irng<br />
la dang nhiet co the xem:<br />
<br />
C'fr, =CH,P = const C^ R,.^,JJ const<br />
tich phan phuong trinh (6) theo su6t chieu dai 16 ta c6:<br />
<br />
\dz^-\<br />
CO., dPc (7)<br />
I K'.i, -^c ' Pc<br />
Od.,<br />
L = .In (8)<br />
K'„ -Mr P'r<br />
trong do:<br />
<br />
P'r p' c{\-U,)<br />
(9)<br />
P'r P'c<br />
\-u,.<br />
vdi Uc la d6 chuyen hoa ctia cau ttr cacbon, nen:<br />
<br />
«, CO,<br />
.\u{\-D,)-- .In (10)<br />
Rc,j M, Reg -Mr •U,<br />
<br />
Tren ca sd lupng hai nudc dupc cap vao 16 va ke den lupng hai nudc sinh ra do chay nhien<br />
lieu, chay chat boc,... theo (6) da tinh dupe van t6c chuyen h6a cacbon trung binh:<br />
<br />
<br />
43<br />
i?,, = 8 , 5 . 1 0 - ^ ^ ^ ^ ^ ^ . (11)<br />
"'' Kg,.phut<br />
Til' cac s l lieu thuc nghiem da thu dupc de dam bao chat lugng (dp xop) ctia than boat tfnh,<br />
dp chuyen hoa clu tti' cacbon can phai dat la 0,3 vi vay thdi gian chuyen h6a can thiet la<br />
1 . 1 1 , 1<br />
T..,. = • -.In—^ = —^—.In = 351,3 (phtit).<br />
R,,„.M, 1-0,3 8,5.10-M2 1-0,3<br />
Theo [10], the tfch viing phan ung dugc tfnh theo cong thu'c:<br />
<br />
V = "•"'^' - ' (12)<br />
R<br />
P.r/3<br />
trong d6: Gngi : nang suit thilt bj phan ting tinh cho nguyen lieu, Gngi = 261,2 kg than/h; P: la<br />
he sl diy CLia thilt bj, lly P = 0,12; pdj: khli lugng rieng do d6ng ctia nguyen lieu: pdd = 586 kg/<br />
m"*; T|: thdi gian luu can thiet ctia than trong vimg phan trng: T| = Ts + Xch-<br />
Vdi:<br />
• Ts: la thdi gian can thiet de nung nong than nguyen lieu ttr nhiet dp thudng den nhiet dp<br />
hoat h6a, vdi nang suat 1500 tan san pham/ nam tfnh dugc TS = 10,3 phtit va thdi gian chuyen<br />
hoa Id, = 351,3 phtit. Ta co: T| = ij -i-id, = 10,3-i-351,3 = 361,6 phtit ~ 6 gid.<br />
Vay:<br />
<br />
V , = i ^ l : ^ = 22,287 ( m ^<br />
586.0,12<br />
Chieu dai 16 khi: D =1,10 m la<br />
V„ 22,287 • , ,<br />
I = ^ V = ^ ^ ^ ^ 2 3 , 5 0 On).<br />
TTD' 0,949<br />
4<br />
Van t6c quay ctia 16 de dam bao 16 quay on djnh xac dinh theo [10]:<br />
m.k.L<br />
n =— (v/ph). (13)<br />
T,.D.tg(p<br />
Vdi (p la goc nghieng cua 16 va chpn: tgcp = 0,01 thi s l vong quay cua 16 la: n s: 1,25 v/ph.<br />
<br />
<br />
4. KET LUAN<br />
<br />
Da lap va giai phuong trinh can bang chat doi vdi qua trinh chuyin hoa clu tti' cacbon<br />
trong than gao dira, tinh dupc thdi gian cin thiet dl boat boa than gao dii'a tai nhiet d6 850°C la<br />
361,6 phtit.<br />
Da thiet lap va giai phuong trinh can bing nhiet cho thilt bj phan ung boat boa, xac djnh<br />
dupc thdi gian can thiet de nung nong than nguyen lieu tir nhiet dp thudng len nhiet dp boat h6a<br />
la r^ = 10,3 phtit.<br />
<br />
<br />
<br />
44<br />
Lly dp nghieng ctia 16 boat h6a la tg(p= 0,01 va dudng kinh ctia 16 D = 1,10m. xac djnh<br />
dupc chieu dai can thiet ciia 16 hoat hoa de dam bao dp chuyen hoa Uc=0,3 (tuong trng thdi<br />
gian phan ting la 361,6 phtit) la 23,50 m.<br />
<br />
Ldi cam on. Bai bao dugc hoan thanh vdi su tai trg cua chuang trinh KHCB NN.<br />
<br />
TAI LIEU THAM KHAO<br />
<br />
1. H. V. Kiele and E. Baedes - Aktivkohle-Herstellung und ihre industrielle Anwendung<br />
Enke verlag, Stuttgart, 1981.<br />
2. Sontheimer H. Veroeff - Des Engle-Bunte Institutes der Univ. Karisruhe 9 (1975) 219.<br />
3. Mai Xuan Ky - Bericht an der TUBA- 1994.<br />
4. Kate K., Matsuura K., Sawamura Y., Mori H., Hanzawa T. - J. of Chem. Eng. Of Japan 13<br />
(3)(1980)214-219.<br />
5. Klei H. E., Sahagian J., Sundstrom D.W. - Ind. Eng. Chem. 14 (4) (1975) 470-473.<br />
6. Mai Xuan Ky, Ta Hong Dire - Tap chi Hoa hpc 43 (2003) 70-81.<br />
7. Mai Xuan Ky, Pham Ngpc Anh, Ta Hong Du'c - Invertigation on Activation of coconut<br />
shell charcoal with steam and Determination of Kinetic model of reaction, RSCE Hanoi<br />
2005 vol. 2, pp. 185-193.<br />
8. Pham Ngpc Anh, Vii Dinh Tien, Mai Xuan Ky - Tap chi Khoa hpc va C6ng nghe 45<br />
(2008)265-271.<br />
9. Mai Xuan Ky - Thiet bj phan u'ng trong c6ng nghiep h6a hpc, Nha xuat ban KH&KT Ha<br />
Npi, 2006.<br />
10. II. Titze - Elemente des Apparatcbaues, Springer Verlag - Berlin - Heidelberg, New Yoi-k,<br />
1967.<br />
<br />
SUMMARY<br />
<br />
Based on the reaction kinetic model established and the principle of heterogeneous reaction<br />
process applied, a rotary kiln was designed to produce continuously activated charcoal from<br />
coconut shell in industrial scale at a production capacity of 1500 ton per year. The mass balance<br />
and heat balance equations were solved at the specific conditions. The essential dimensions of<br />
the equipment, the reaction time and the energy consumed to maintain the stable state at 850°C<br />
were determined. The results can apply to design the reactor used for activating coconut shell<br />
charcoal in industrial scale.<br />
<br />
<br />
Dia chi: Nhdn bdi ngdy 25 thdng 9 ndm 2008<br />
Tru'dng Dai hpc Bach khoa Ha Npi.<br />
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45<br />
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