TuyIn tap bio cio Hpi nghj KHCN "30 nim Dau khi Vift Nam Cff hpi mdi, thach thde mdi" 77̂ KHA NANG H A P PHU CAC TAP CHAT CUA M Q T SO LOAI ZEOLIT Sir DVNG TRONG CONG NGHE Xif LY KHI Vo Thj Lien Tdng[.]
Trang 1TuyIn tap bio cio Hpi nghj KHCN "30 nim Dau khi Vift Nam: Cff hpi mdi, thach thde mdi" 77^
KHA NANG H A P PHU CAC TAP CHAT CUA M Q T SO LOAI ZEOLIT
S i r DVNG TRONG CONG NGHE Xif LY KHI
Vo Thj Lien
Tdng cdng ty Ddu khi Viet Nam
Le Manh Hiing
Cdng ty Dung dich khoan vd Hod phdm Ddu khi
TOM T A T
Tir ndm 1954, cdc logi zeolit tdng hap da duac img dung thdnh cdng trong nhiiu
linh vice Dac biet trong linh vuc xir ly khi cdc zeolit duac sir dung nhu cdc chdt hdp phu
Nhiiu logi zeolit nhu zeolit A, X, P da duac sir dung trong ldm khd khi xir ly khi tdch cdc
tgp chdt nhu CO2, H2S, NH}, mercaptan, v.v Cdc qud trinh khdc nhu ldm sgch khi sdn xudt khi O2, khi N2 zeolit cUng duac sic dung nhu cdc chdt hdp phu Bdo cdo giai thieu vi mpt sd zeolit da icng dung trong cdng nghi xir ly khi vd dang Id sdn phdm thuang mgi
Ddng thdi giai thieu khd ndng hdp phu mpt sd tgp chdt thudng gap trong cdc ddng khi
DAT V A N D E
Xir ly khi bao gdm cac van de nhu say khd khi, tach va lam sach khi nham thu dugc
ddng khi cd thanh phan dap ung cae yeu eau cho van chuyen, tang trii, che bien va sir
dung Nhirng giai phap de xir ly cac ngudn khi la: hap thy, hap phy va ngung ty Vdi
phuang phap hap phu, cae loai vat lieu thudng dugc sir dyng nhu than boat tinh, nhdm
oxit, kem oxit, sat oxit, silicagel va zeolit Hien nay, loai vat lieu hap phy zeolit dugc sir
dung rat phd bien, do loai vat lieu nay cd cae uru diem ndi trdi so vdi cac loai vat lieu khae
nhu do chgn lge hap phu va dung lugng hap phu cao
C5 Viet Nam, trir lugng khi kha ldn, trong khi cd lan hoi nude va cac tap chat nhu
H2S, NH3, CO2 nen cin phai xir ly trudc khi van chuyin, tang trir, che bien va sir dung
Hien nay, vat lieu zeolit da dugc sir dyng trong Nha may xir ly khi Dinh Cd de lam khd
khi Trong nha may dam va nha may Igc dau ciing cd cac ngudn khi can xir ly nhu khi
cracking, khi hydro tir reforming, khi thai, v.v Cac ITnh vue khae nhu xir ly mdi trudng,
san xuat khi cdng nghiep, san xuat khi cho y te, san xuat thue pham ciing can mdt lugng
chat hap phu kha ldn Vi vay, nghien ciiu cae zeolit hap phu va tien tdi san xuat loai vat
lieu nay d nude ta se dap ung dugc cac yeu eau thuc tien dat ra
NHOM c A c ZEOLIT H A P PHU vA PHAM VI iTNG DUNG
Hinh 1: Cau true tinh the zeolit A
Trang 2' 8 Kha ning hap phu cac tap chat cua mpt so loai zeolit sd dung t r ^ n g ^
L Zeolit hap phu thuoc nhdm zeolit A
a Zeolit 3A (KA)
La loai aluminosilicat kim loai kiem cd dudng kinh mao quan khoang 3 Angstroms (0,3nm) Vdi kich thudc mao quan nhu vay, zeolit 3A cd kha nang hip phy cac cau tir nhu hoi nude, cdn cac phan tir cd dudng kinh ddng hgc ldn hon bj giir lai
Cdng thirc hoa hgc ciia zeolit 3A la:
0.45 K2O 0.55 Na20 AI2O3 2Si02 n HjO LTnh vuc ap dyng cua zeolit 3A:
- Tach nude tir cac hydrocarbon chua no nhu etylen, propylen, butadien, v.v
- Lam khd khi thu dugc tir cracking
- Siy khd khi ty nhien nlu yeu cau giam thieu lugng COS tao thanh hoae giam thieu lugng hydrocarbon bj hap phy
- Tach nude tir eae hgp chat cd eye nhu metanol, etanol
- Lam khd cac tac nhan lanh nhu R22, Rl34a
- Lam khd thuy tinh each dien
Zeolit 3A dugc tai sinh bang ddng khi khd cd nhiet do dii de say ndng khdi zeolit tang dan len va duy chi d nhiet do 200 - 230 °C trong thdi gian 2 - 3h Khi diing lam khd ddng khi chira hydrocarbon olefin, tai sinh zeolit KA d nhiet do thap cd the giam thieu lugng polime tao thanh, loai zeolit nay cd the lam khd ddng khi xudng dudi 0,1 ppm H2O Cac chat hap phy zeolit 3A cua Cdng ty ZEOCHEM nhu Z3-01 (diing cho lam khd khi cracking, lam khd khi dau md), 02 (diing eho loai nude cua etanol, metanol),
Z3-03 (diing cho loai nude ciia khi ty nhien), Z3-04 3A-8KM (diing cho loai nude ciia tac nhan lanh), IS0M0L3 (diing tach im eho thuy tinh each dien)
b Zeolit 4A (NaA)
Zeolit 4A cung thudc loai aluminosilicat kim loai kiem cd dudng kinh mao quan khoang 4 Angstrom (0,4nm) Zeolit 4A cd thi hip phu hiu hit cac phan tir ed kich thudc ddng hgc nhd ban 4A*', ngan chan cac phan tir cd kich thude ldn hon Cac loai phan tir cd the hap phu dugc nhu O2, N2, CO2 va hydrocarbon ngoai trir cac hydrocarbon mach nhanh
va hydrocarbon thom
Cdng thirc hoa hgc eiia zeolit 4A la:
Na20 AI2O3 2Si02 n H2O LTnh vyc ap dyng:
- Say khd va tach khi CO2 tir khi ty nhien, LPG, khdng khi, khi tro va cac loai khi khae
- Tach cac hydrocarbon, amoniic va methanol tir cac ddng khi (qua trinh xir ly khi tdng hgp amoniac)
Zeolit 4A duge tai sinh bing ddng khi ndng, nhiet do ciia khdi zeolit duge tang din
Trang 3Tuygn tap bio cio Hpi nghj KHCN "30 nim Dau khf Vift Nam: Cff hpi mdi, thich thde mdi" 79^
len 250 - 300°C va duy tri trong thdi gian 2 - 3gid Loai zeolit dugc tai sinh thich hgp cd
thi ha nhiet do dilm suong cua ddng khi xudng - lOOT va ham lugng CO2 xudng dudi
5ppm
Cac san phim chit hip phy zeolit 4A ciia UOP nhu: 4A-DG MOLSIV chiem tren
60% lugng cac chit hip phy dugc sir dyng trong qua trinh lam khd khi ty nhien tren the
gidi, UI-94 MOLSIV dugc sir dung nhilu d Trung Ddng, Bic My, UOP IlK-38 va
4A-LNG de tach CO2 va mercaptan cd phan tir khdi thap da dugc sir dyng trong hon 100 nha
may tren the gidi Nhdm cac san pham chira zeolit 4A ciia ZEOCHEM gdm Z4-01 diing
trong qua trinh lam khd cac khi tro, CO2 hoae khdng khi, Z4-02 diing trong cdng nghe san
xuat khi LNG, Z4-04 diing trong qua trinh lam khd khi ty nhien, 4A-8BL diing trong cac
loai phanh hoi ciia xe bus, xe tai, tau boa de lam khd, 4A-8KM diing lam khd cac tac nhan
lanh
c ZeoUt 5A (CaA)
La loai aluminosilicat kim loai kiem, trong cau tnic tinh the zeolit 5A cd khoang 70
- 75% ion natri dugc thay the bang ion canxi Dudng kinh mao quan ciia zeolit 5A khoang
5 Angstrom cd the hap phy cac phan tir cd kich thudc ddng hgc nhd hon 5A" Loai zeolit
nay dac biet thich hgp eho cdng nghe hap phu PSA (pressure swing adsorption), d dd
chung dugc sir dyng de tach rieng n-paraffin va iso-paraffin (C4, C^), san xuat oxy, nito
tinh khiet diing trong y te
Cdng thirc boa bgc ciia zeolit 5A la:
0.7 CaO 0.3 NazO AI2O3 2Si02 n HjO LTnh vyc ap dyng:
- Tach nude, CO2, H2S tir khi ty nhien, giam thieu sy tao thanh COS Loai zeolit
nay cdn cd the hap phy cac mercaptan nhe
- Sir dyng eho tach rieng n-paraffin va iso-paraffin
- San xuat cac khi N2, O2, H2 va eae khi tro khae cd do tinh khiet cao
Zeolit 5A duge tai sinh bang edng nghe PS (pressure swing) hoae bang ddng khi
sach cd nhiet do dii dl lam ndng zeolit len din nhiet do 200 - 300 "^C Neu dugc tai sinh
thich hgp thi loai zeolit nay cd the lam giam nhiet do diem suong xudng - lOO'^C va ham
lugng CO2 hoae H2S xudng dudi 5ppm
Cac san phim 5A ciia ZEOCHEM gdm: Z5-01 diing de phan tach isome, Z5-02
diing trong lam sach khi ty nhien giam thieu ham lugng COS, Z5-03, Z5-04 diing trong
qua trinh lam giau oxy, Z5-05 diing trong qua trinh lam sach hydro San pham ciing loai
cua UOP nhu COSMIN, MOLSIV, v.v
2 Zeolit thudc nhom zeolit X
Hinh 2: Cau triic tinh the zeolit X
Trang 480 Kha ning hap ph^ cie tap chat cua mpt so loai zeolit sd dung t£on£:^
a Zeolit lOX
Loai zeolit nay cd dudng kinh mao quan khoang 8 Angstrom (0,8nm), tinh the zeolit lOX cd ciu triic kilu faujasit Trong zeolit lOX khoang 75% ion Na"" dugc thay the bang ion Ca^"^ Zeolit CaX cd the nhan duge tir qua trinh trao ddi cafion ciia zeolit dang NaX
Cdng thirc hoa hgc ciia zeolit I OX la:
(0.83 ± 0.05) NajO AI2O3 (2.48 ± 0.03)SiO2 n HjO LTnh vyc ap dung:
- Lam chit hap phy cac phan tir khi cd dudng kinh ddng hgc nhd ban kich thudc mao quan (8A°)
- Diing lam xuc tac, tach chat
Loai zeolit cd tinh chat tuong ty zeolit lOX la Zeolon Na (My), Zeosorb (Ddng Dire), Calsite (Tiep), CaX (Lien Xd cu)
b Zeolit 13X
Loai zeolit nay cd dudng kinh ldn hon nhieu so vdi zeolit A Dudng kinh mao quan ciia loai zeolit nay vao khoang 7,4 angstrom (0,74nm) cho phep hap phy cac phan tir cd dudng kinh ddng hgc nhd hon 9A'' Loai zeolit 13X cd dung lugng hap phy va tdc do chuyen khdi cao Zeolit 13X cd the tach cac tap chat cd kich thudc ldn hon nhieu so vdi kich thudc mao quan cua zeolit A
Cdng thirc hoa hgc ciia zeolit 13X:
Na20 AI2O3 2.5 Si02 n HjO LTnh vuc ap dung
- Tach CO2 va am tir khdng khi
- Tach, lam giau oxy tir khdng khi
- Tach mercaptan, H2S tir khi ty nhien
- Tach cac chat oxy boa tir cac hydrocarbon
- Tach cac n-paraffin ra khdi cac chit thom
- San xuat oxy tinh khilt diing cho Y tl
Cac san pham zeolit 13X nhu ZlO-2 (diing trong cdng nghe tach rieng hydrocarbon olefin), Zeochem (diing trong qua trinh tach mercaptan va H2S), Z10-01 (la loai 13X tieu chuin diing trong lam sach khdng khi), Z10-03 (diing trong san xuit oxy), Z10-04,
ZIO-06, v.v ciia Cdng ty ZEOCHEM Ngoai ra, cdn cd Zeosorb 13X (Ddng Diic), Nalcit 13X (Tiep),^ v.v Cdng ty UOP vdi san phim 13XAPG dugc sir dung trong nhilu nha may san xuit khi oxy va nito tren thi gidi
Loai zeolit 13X dugc tai sinh bing ddng khi khd cd nhiet do cd the nang nhiet do ciia khdi zeolit len 250 - 300"C Loai zeolit 13X dugc tai sinh thich hgp cd thi ha nhiet do suong ciia ddng khi xudng -lOO^C, ham lugng mercaptan va CO2 xudng dudi mirc 2ppm
Trang 5Tuygn tip bio cio Hpi nghj KHCN "30 nim Dau khi Vift Nam: Cff hpi mdi, thich thde mdi' 81
K H A N A N G H A P PHU MOT SO T A C N H A N CO HAI CUA CAC LOAI ZEOLIT
HAP PHU
Trong khi diu md, khdng khi va khi thai chiia cac tap chat cd hai gay anh hudng tdi mdi trudng va quy trinh cdng nghe nhu cac hgp chat chiia luu huynh, NH3, CO2, hoi nude Tuy theo yeu ciu vl nguyen lieu, san pham khi va eau true, tinh chat, dung lugng hap phu ddi vdi mdi loai tap chat ciia timg loai zeolit ma cd the lya chgn mdt trong cac loai zeolit tren sir dyng lam tac nhan hap phy trong cac qua trinh edng nghe lam sach, tach cac tap chat ed hai dd ra khdi ddng khi
1 Kha nang hap phu hoi nirdc ciia cac zeolit hap phu
Viee tach hoi nude trong ddng khi hay edn ggi la qua trinh lam khd khi la mdt trong nhirng cdng doan quan trgng trong qua trinh san xuat khi hoa Idng, qua trinh san xuat oxy, nito, qua trinh lam khd cdn, lam khd thuy tinh each dien Hoi nude thudng gay ra cac tac hai nhu tao thanh hydrat, an mdn dudng dng, lam thay ddi cac dieu kien lam viec binh thudng cua he thdng thiet bj
De de dang so sanh dung lugng hap phu hoi nude cua cae loai zeolit hap phu trong
ciing mdt dieu kien xem Hinh 3
Dung lugng hap phy la ham ciia nhieu yeu td nhu nhiet do, ap suat, ban chat chat hap phy, chat bj hap phy do vay de so sanh phai dua ve ciing dieu kien hap phu Tir Hinh
3 va Bang I ed the thay zeolit CaX la loai ed dung lugng hap phy ddi vdi hoi nude cao nhat Sau dd la CaA, NaA cdn NaX hap phy hoi nude kem hon Tuy nhien, trong thyc tien loai zeolit NaA va NaX tdng hgp de hon so vdi cac loai kia nen mac dii dung lugng hap phy thap hon van dugc sir dyng nhieu
Bang 1: Dung lu'ong hap phu hoi niroc cua cac loai zeolit hap phu
TT
1
2
3
4
Logi zeolit hdp phu
NaA(4A)
CaA(5A)
NaX(13X)
CaX(lOX)
Dieu kien hdp phu
"K
298
-298
-298
-300
-mmHg 0,025 0,1
4
20 0,025 0,1
4
20 0,4
1
20
3
20
Dung luang hdp phu g/g
0,16 0,20 0,25 0,28 0,19 0,22 0,27 0,30 0,24 0,26 0,24 0,31 0,36
Trang 682 Khi ning hap phu cie tap chat cua mpt so loai zeolit sir dung tr^ng»
~5i)
U
40
35
30
25
20
15
10
5
0
f=A ri\ ^ i
-ffllTF
^ — — — i ^ _ — — — !
-d fd I Li 1 K _ NaA CaA NaX CaX
Hinh 3: Dung lu-ong hap phu hoi nu-dc d 298''K, 20 mmHg
(C; dung luang h ap ph u)
1 Kha nang hap phu NH3
Trong khi thai, trong khi tir qua trinh van ehuyin, tang trii, che biin rac thai cd chiira mdt lugng dang kl khi amoniac, tir nha may san xuat dam ciing thoat ra mdt lugng khi NH3 Ngoai ra, trong khi tu nhien va khi ddng hanh ddi khi ham lugng khi NH3 ciing vugt cac tieu chuin eho phep Zeolit la chat ed kha nang hap phu tdt khi NH3, vi vay zeolit dugc sir dung lam chat hap phu de loai bd NH3 trong cac ddng khi
Bang 2: Dung lirong hap phu khi NH3 cua cac loai zeolit hap phu
TT
1
2
3
4
Logi zeolit hdp phu
NaA (4A)
CaA(5A)
NaX(13X)
CaX(IOX)
Dieu kien hdp phu
«K
298
-298
-298
-298
-mmHg
3
10
100
3
10
100
2
10
100
2
10
100
Dung luang hdp phu g/g
0,090 0,11 0,15 0,10 0,135 0,175 0,10 0,14 0,175 0,10 0,14 0,185
Sd lieu trong Bang 2 cho thiy dung lugng hip phy NH3 ciia CaX d lOOmmHg cao nhit, ciia CaA, NaX bing nhau va thip hon so vdi CaX mdt chiit Trong ciing mdt dilu kien, dung lugng hip phu NH3 cua CaX bao gid ciing ldn hon ba loai kia Dilu nay cang thay rd ban khi so sanh tren Hinh 4
Trang 7Tuyen tap bio cio Hpi nghj KHCN "30 nSm Dau khi Vift Nam: Cff hpi mdi, thich thde mdi" 83
o
U
201 0
5
0
-p
• P=10
• P=100
Hinh 4: So sanh dung lirong hap phu NH3
3 Kha nikng hap phu CO2
Khi CO2 la mdt trong cac khi axit gay tac hai an mdn thilt bi, dudng dng khi cd mat hoi nude La loai khi khdng chay, khi cd mat trong khi LPG, LNG se lam giam nhiet chay cua khi Trong qua trinh san xuat khi nito, oxy tir khdng khi, trong qua trinh che bien khi
tu nhien va khi ddng hanh can phai loai bd khi axit nay Cac ngudn khi dau md d Viet Nam thudng cd ham lugng CO2 kha cao, dac biet la cac md khi nam d khu vyc mien Bae
va miin Trung
Ddi vdi khi CO2, dung lugng hap phu ciia cac loai zeolit cd su thay ddi dang ke Khi
ap suat tang, dung lugng hap phu ciing tang, dung lugng hap phu CO2 cua CaX va NaX d
ap suat va nhiet do nhu trong Bang 3 cao hon hai loai zeolit A CJ P = 100, ba loai CaX, NaX, CaA cd dung lugng hap phu bang nhau Dieu nay thay rd hon tren Hinh 5
Bang 3: Dung lu-ong hap phu khi CO2 ciia cac zeolit hap phu
TT
1
2
3
4
Logi zeolit hdp phu
NaA (4A)
CaA(5A)
NaX(13X)
CaX(lOX)
Dieu kier
"K
298
-298
-298
-298
-! hdp phu
mmHg
2
10
100
700
1
10
100
700
2
10
100
700
20
100
700
Dung luang hdp phu, g/g
0,070 0,12 0,165 0,20 0,066 0,13 0,20 0,24 0,06 0,10 0,20 0,26 0,125 0,20 0,26
Trang 884 Khi ning hap phy cie tap chat ciia mpt so loai zeolit sd dying troiig^
o
u
• P=10
• P=:100 OP=700
Hinh 5: So sanh dung lu-ong hap phu CO2
4 Kha nang hap phu khi H2S - , Cac hgp chit chiia luu huynh nhu H2S, mercaptan, v.v cd mat trong cac ngudn khi diu gay tac hai din mdi trudng, gay an mdn thiet bj, dac biet khi cd mat hoi nude d nhiet
do va tdc do di chuyin cao Day la mdt loai khi axit thudng cd mat trong khi dau md, khi thai cua cac phan xudng thu hdi luu huynh, khi ciia qua trinh cracking, v.v trong nha may lge diu (ddi vdi qua trinh cracking nlu trong nguyen lieu cang chira nhieu luu huynh thi trong khi cracking cang nhilu H2S), khi tir cae qua trinh xir ly chat thai Khi H2S la loai khi rit ddc hai cin phai phai loai bd hoae giam thieu trudc khi sir dyng hay thai ra mdi trudng Zeolit la vat lieu cd ai lye vdi loai khi nay cho nen cd the sir dyng vat lieu hap phu zeolit cho myc dich lam sach H2S ra khdi ddng khi
Cac sd lieu trong Bang 4 cho thiy zeolit NaX cd dung lugng hip phu ddi vdi H2S d nhiet do 298°K va ap suit 10, 100, 400mmHg cao hon NaA va CaA Dilu nay dugc thiy
rd hon tren Hinh 6
Bang 4: Dung lirong hap phu H2S ciia cac zeolit hap phu
TT
1
2
3
4
Loai zeolit hap phu
NaA(4A)
CaA(5A)
NaX(13X)
CaX(lOX)
Dieu kien hap phu
°K
298
-298
-298
-298
-mmHg
10
100
400
10
100
400
10
100
400
10
100
400
Dung lugng hap phu, g/g
0,16 0,22 0,24 0,21 0,28 0,30 0,224 0,294 0,34
Trang 9
-Tuygn tap bio cio Hpi nghj KHCN "30 nim D5u khf Vift Nam: Cff hpi mdi, thich thuc mdi" 85
~5o
nP=io
• P=100 QPMOO
Hinh 6: So sanh dung lirgng hap phu H2S KET LUAN
Vat lieu hap phu zeolit cd iing dyng rdng rai trong cdng nghe san xuat khi ty nhien, khi dau md hoa Idng, trong qua trinh lam khd cac khi cracking va khdng khi Dac biet, zeolit hap phu cdn dugc diing trong san xuat eae loai khi cdng nghiep, khi oxy eho y te
Trong qua trinh lam khd cac chat phan cue manh nhu etanol, metanol, cac tac nhan lanh nhu R22, lam khd nhien lieu phan luc, v.v sir dung loai zeolit 3A (KA) do loai zeolit nay cd dudng kinh mao quan la 3A° nen cd do chgn loc hap phu nude rat cao, khdng hap phy cae cau tir khae ed dudng kinh ddng hgc ldn hon 3A°, vi vay tranh dugc sy hap phy cau tir cd ich
Trong qua trinh xir ly khi dau md mac dii zeolit CaX va CaA cd kha nang hap phu hoi nude, H2S, CO2 cao, nhtrng trong cac ngudn khi xir ly chira nhieu cau tir
cd kich thude ddng hgc rat khae nhau Neu sir dyng cac loai zeolit ed dudng kinh
Id xdp ldn se dan den kha nang ddng hap phy cac eau tir cd ich trong ddng khi nhu cac hydrocarbon CH4, C2H4, v.v Mat khae, viec san xuat zeolit 5A va lOX phiic tap hon, gia thanh cao hon do vay sir dyng loai zeolit NaA va NaX la hgp
ly
Trong ITnh vuc xir ly mdi trudng, hau het cac ciu tii trong ddng khi deu can phai lam sach nen cd the lya chgn loai zeolit cd dudng kinh mao quan ldn vdi dung lugng hap phu eao nhu NaX, CaX, CaA
Trong cdng nghe san xuat khi oxy cd do tinh khiet cao tir khdng khi, sir dyng loai zeolit 5A do loai zeolit nay cd kha nang hap phy chgn lge ddi vdi nito, CO2, H2O cao hon nhieu so vdi oxy
Tuy nhien, de xet hieu qua eiia qua trinh hap phu edn phai tinh den yeu td gia thanh vat lieu Dac biet edn phy thude vao cac dieu kien cdng nghe nhu nhiet do,
ap suat va su cd mat ddng thdi cac tac nhan hap phy canh tranh trong ddng khi
T A I L I E U THAM K H A O
I Salil U Rege, Ralph T Yang, Mack A Buzanowski, 2000 Sorbents for air
purification in air separation Chemical Engineering Science 55
Trang 1086 Khi ning hap phg cie tap chat cua mpt s6 loai zeolit sir dyng tj;ong^
2 Mark W Ackey, Salil U Rege, Himanshu Saxena, 2003 Application of natural zeolites in the purification and separation of gases Microporous and Mesoporous
Material 61
3 R Szostak, 1992 Handbook of molecular sieves Van Nostrand Reinhold, New York
4 Donald W Breck, 1974 Zeolite molecular sieves: Structure, Chemistry and Use New
York
5 Yang R.T., 1997 Gas separation by adsorption process London Imperial College
Press
6 Vd Thi Lien, 2004 Mpt sd gidi phdp ngdn ngira su tgo thdnh hydrat trong qud trinh khai thde, van chuyen vd che bien khi tie nhien vd khi ddu md Tap chi Dau khi, Sd 6
7 Vd Thj Lien, 2004 Uu the cua chdt hdp chua zeolit so vai mpt sd vdt li?u hdp phu rdn khdc trong cdng nghe xir ly khi Tap chi Dau khi, So 8