VAI^ DE K H I HOA THATV
GS.TS. N G U Y I N QUANG PHiCH Trudng Dai hoc Md - Dja chat After dealing with some key methods for coal gasification that have been widely applied on the world nowadays, the paper introduces the application of these methods to thermal power plants with the concrete analysis of their advantages and disadvantages as well.
1. Khai quat
Khf hda hay hda khf than la phUdng phap chuyen hda than sang the khf bang each SLf dung cac chat hda khf. De hda khf than can thiet phai cd mpt lupng nang lupng chuyen hda than. Trong qua trinh hda khi tu cap nhiet thi nhiet lupng can cho phan Lfng dupc hinh thanh do chay mpt phan than trong lupng than dupc hda khi;
cdn trong qua trinh hda khi khdng tu cap nhiet thi nhiet lupng can cho phan Lfng dupc cap tLf ngoai vao.
Vdi phUdng phap khi hda tu cap nhiet, cac chat bd trp cho qua trinh hda khf la khf P xy hoac khong khf va hydrd; ddi khi cung trdn them hdi nudc va khf cacbon didxft. Cac thanh phan chay dupc cCia khf thanh pham la cac bon m6n 6xi't (CQ) hydro (Hj) va metan (CH4).
Dien bien cua qua trinh khf hda va san pham cua qua trinh khf hda dUpc dieu chinh bang each thay ddi cac tham
sd cua qua trinh nhu ap suat, thanh phan va lupng cua cac chat bd trp. Khi silr dung hdn hpp khong khf va hdi nudc se nhan dupc "khf nhe" hay "khf ddt" , dupc SLf dung de san xuat dien. Oe cd dupc "khf tdng hpp" hay "khf hoan nguyen" de siJ" dung trong cdng nghiep hda chat, can phai SLf dung khf bd trp la hdn hpp oxy va hdi nudc. Trong phUdng phap khf hda SLf dung hydrd se nhan dupc san pham la khf metan.
Qua trinh khf hda dupc dac trung bdi mpt loat cac phan Lfng ddng the (ddng nha't- homogen) va phan Lfng dj the (khong ddng nhat-heterogen).
Trong cac phan Lfng hda hpc, gia thiet than tdn tai d dang cacbon, cdn cac thanh phan khac nhu ni td, hoac cac khf trd trong chat khf bd trp, cung nhu tro va luu huynh, khdng tham gia, hoac chi tham gia d mCfc dp thap vao qua trinh khf
hda, nen cd the bd qua, khdng xet den trong cac phan Lfng.
TU dd nhan dupc 4 phUdng trinh phan Lfng dj the cd ban va khPng phu thupc tuyen tfnh, phan anh sU chuyen hda giua khf va vat lieu ran. Trong bang 1 gidi thieu cac phan Lfng cd ban, lupng entanpi cho phan Lfng nghjch de chuyen hda cac bon thanh than cdc, cung nhu anh hudng cua nhiet 66 va ap suat den phan Lfng.
Cac phan Lfng nay khPng dan den sU chuyen hda hoan toan, ma cac thanh phan tham gia phan Cmg cd xu hudng tien tdi mpt trang thai can bang, phu thupc vao nhiet dp va ap suat, tuan theo djnh luat bao toan khdi lupng.
Chang han theo nguyen tac CUPng bLfc nhd nhat, cac phan Lfng thu nhiet (2) va (3) xay ra theo hudng thuan Ipi de hinh thanh CO va Hj khi nhiet dp tang, cPn phan Lfng cho me tan theo phuong trinh (4) lai giam.
Ngupc lai, khi tang ap suat tang thi trang thai can bang cua cac phan Lfng (2) va (3) cd xu the theo chieu nghjch, hudng den cac cau tLf ban dau cija phan ung. Su hinh thanh CO va H2 se giam di, nhung lai thuan Ipi de hinh thanh me tan CH4. Phan Lfng chay (1) hau nhu xay ra hoan toan, do vay d trang thai can bang hau nhu khdng cdn d xy tu do.
Bang 1. C^c phan ling hda hoc cua qua trinh khi hda than
Loai phan umg
Chay hoan toan Phan Lfng Boudouard Ph^n Lfng khf hoi nUdc Phcin Lfng tao metan
Cong thurc hoa hoc
Ce&+02=C02 (1) Cc5c+C02=2CO (2) Cc4c+H20=CO+H2 (3) C^+2H2=CH4 (4)
Hieu sd entanpi AH
kJ/mol -406 +159,9 +118,7 -86,3
Anh hudng cua Nhiet do
<- -^
-^
<-
Ap suat khdng
<—
<—
->
KHCNM* S 6 122008* Cllfi B I £ N SLT DUNG THAN
Thong tin khoa hpc cong nghe m o
DUdng nhien cac phUdng trinh can bang cung chi md phdng khdng hoan toan cac qua trinh thuc te. Hdn hpp khi bj chi phdi bdi qua trinh ddng hpc cua phan Lfng. Qua trinh nay lai phu thupc vao dieu kien ve nhiet dp, ap suat trong Id hda khf, cung nhu cac qua trinh trao ddi vat chat, trao ddi nhiet d dd.
Dpng hpc cua phan Lfng dupc dac trung bdi mdt loat cac phan Lfng hap thu, hap phu, chuyen hda, khCf, xac djnh bdi cac tham sd khac nhau cua cac phan ung dd.
Tach nhiet va hda khf xay ra ddng thdi va chi phdi l i n nhau. Chang han cac thanh phan khf me tan va hydrd xuat hien trong ca hai qua trinh, do vay khao sat rieng tLfng qua trinh la viec khd khan. Than vdi ham lupng chat bdc cao thudng cd tfnh phan Lfng manh, do vay qua ham lUpng chat bdc cd the danh gia dupc dac tfnh tham gia phan Lfng cua than va dpng hpc cua cac phan Lfng hda khf.
NHAMAYNHI$TOI$N THAN NAU
43°/c
1992: 36%
2005: 43%
Muc tieu 2020 : >50%
Ngay nay, tfnh kinh te cua viec hda khf than de san xuat khf ddt, khf tdng hpp va khf hoan nguyen hoac khf da't nhan tao v i n bj phu thudc vao gia dau, loai nhien lieu hang dau. Khi gia dau thap va kha nang cung cap dau cdn du thi hda khf than la khdng kinh te.
Tuy nhien hda khf than dupc phat trien vdi muc tieu san xuat dien ket hpp tua bin khf va tua bin hdi nUdc hCfa hen kha nang tang hieu suat sCf dung than va cai thien tfnh than thien vdi mdi trudng.
Tren hinh 1 la vf du ve cac nha may nhiet dien sCf dung than nau, than da va nha may ket hpp tua bin khf vdi tua bin hdi nudc d DCfc nam 1992, nam 2005 cac chi tieu ky thuat va muc tieu se dat dUpc vao nam 2020.
2. Cac phu'dng phap khi hoa than
Cac phUdng phap hda khf than cung dupc phan Icai tUdng tu nhu cac phUdng phap ddt than, theo trang thai luu bien cCia than trong 16 hoa khf (Hinh 2). Ngudi ta phan biet
N H A M A Y N H I $ T D I $ N THAN OA
qua trinh chuyen hda than d trang thai 60 than tTnh hoac lang cham, theo phUdng phap tang cd djnh; d trang thai chuyen ddng xoay, theo phUdng phap tang xoay (hay tang sdi) va trong ddng bay cua bpt/bui than theo phUdng phap ddng bay. Ngoai ra cdn cd cac phUdng phap dac biet de chuyen hda than trong cac be kim loai hay be xi. Nguyen ly cua cac phUdng phap khi hda tang cd dinh, tang xoay (tang sdi) va phun bpt/bui than (ddng bay) dupc the hien tren hinh 3, tren cd sd mpt sd loai Id hda khi cd tren thi trudng.
Ndi chung cac phUdng phap hda khf than cung da dupc nghien cCfu, phat trien sdm. Mpt sd phUdng phap cu the da va dang dupc sCf dung bao gdm :
+ Khi hda tang cd dinh Sasol-Lurgi, phat trien tU khoang 1925;
+ He thdng hda khf BGL (British Gas Lurgi), hay hda khf trong be xi than, silf dung tai Schwarze Pumpe, OCfc;
NHAMAYNHI$TDI$N KHf VA HOI NUCJC
1992: 43%
2005: 47%
IVIuc tieu 2020 : >53%
1992: 52%
2005: 58%
Muc tieu 2020 : >60%
Hinh 1. Cac loai nha may dien va chi tieu ky thuat. Ngu6n:Siemens
KHCNM* SO 12/2008* CHE B I £ N SLT DUNG THAN
khf + san pham phu
than
o xy + hoi nudc Tang cd djnh
khi
T dxy +
t r o h/-(i rtitrl xy hoi nudc Tang xoay/sdi
1 +
d xy
than
hoi nudc
11
-:•:'---•-:':
tro
Ddng bdt/bui than Hinh 2. Cac phuong phap khi hda than
Phuong phap tang cd dinh (SOO-IOOCC; 10-100bar)
than (3-30mm)
L
khi+ Hda khf Winkler hay cdn gpi la phUdng phap Winkler nhiet dp cac HTW, sCf dung cho than nau, than bun, gd va chat lang d cac be lang.
PhUdng phap nay dupc nha hda hpc Franz Winkler phat trien tCf 1921 tai Hang BASF.
Day la phUdng phap tang xoay hay tang sdi.
+ PhUdng phap hda khf ddng bay Krupp-Koppers- Totzek, dupc phat trien khoang nam 1952;
+ Cac phUdng phap hda khf dong bay cua hang Shell, cua
Phuong phap tang xoay (800-1100°C; 10-25bar)
hoi +
Phuong phap dong bay (1500-1900°C:25-40bar)
khi
than 1 (0,1mm) J ' 1^ ,
hrti + r
iJXji
han
hoi + 0
Hinh 3. Mdt so dang Id hda khi hang General Electric, hay Texaco va E-Gas cua Conoco Phillips
Nhilmg phat trien mdi sau nay chCi yeu tap trung vao viec tang ap suat trong qua trinh hda khf dd'i vdi cac ky thuat va cdng nghe da dupc danh gia tdt trong thuc te. Sau day gidi thieu sd lupc ve cd sd ky thuat cua cac phUdng phap, pham vi SLf dung hay dieu kien ap dung va cac van de lien quan vdi mdi trudng.
2.1 Khi hoa bang phUdng phap tang cddjnh
Cd sd ky thuat
Khf hda tang cd djnh cd the hoat dpng theo cac che dp chuyen dpng khac nhau giCra dPng than va dPng khf tiep vao Id hda khf, cu the than va khf cd the dupc cap vao cung chieu, ngUpc chieu hay d dang phdi hpp.
Vf du phuong phap Lurgi lam viec theo che dp dPng ngUpc chieu.Than di chuyen tLf phfa tren xudng, do vay than dupc xay khP ngay d vung tren cung cua 16 hoa khf, tiep do la chay u; cac san
KHCNM* S6 12/2008* CHE BlfiN SL) DUNG THAN
Thong tin khoa hpc cong nghe m o
pham cua qua trinh chay u dupc day ra ngoai cung san pham khf. Phan Lfng hoa khf xay ra d nhiet dd 650 den 80q°C cua than 'di chuyen xudng phfa dUdi vdi khf bdc len tLf phfa dudi bdi qua trinh dot chay mpt phan lupng cdc dulai.
Khoang 15% cua tdng lupng than chay d dang than cdc du lai vdi d xy va thoa man nhu cau ve nhiet nang cho qua trinh hoa khi.
Mpt Id hoa khf vdi dudng kfnh den 5m cd the cd dupc cdng suat khf hoa khoang tren 50 OOOm^/gid.
Pham vi (ing dung
De cho ludn cd dupc mdt 66 tham thau khf nhat djnh trong qua trinh khf hda tang cd djnh, nen than sCf dung phai cd CO hat xac dinh va khdng dfnh ket vdi nhau trong qua trinh hda khf.
Cac van de moi tru'dng Do cd qua trinh 'chay u' nen trong san pham khi ngoai lupng khf metan Idn bdc ra, cung cdn cd nhieu hydrocacbon, nhu benzol, nhUa hac fn dupc tach ra khdi san pham khf va dupc SLf dung lam nguyen lieu cho nganh hda.
Ve quy luat phan bd cija lupng luu huynh trong than d cac dang san pham hoa khf, cd the tham khao cac gia tri sau:
+ Khoang 10% den 20%
nam lai trong chat thai CLia qua trinh hda khf,
+ San pham than u chCfa khoang 1 den 2% trpng lUdng luu huynh,
+ Lupng luu huynh cdn lai chuyen sang the khf, trong dd khoang 98% d dang HjS, cdn lai d dang COS.
Phan Idn khf nitd cd trong than dupc chuyen hda trong vung than u thanh amdniac.
Cac thanh phan cd tfnh xam thuc trong san pham khi, vi du nhu HjS, amdniac can dupc tach ra qua cdng doan lam sach khf.
TUdng t u nhu trong qua trinh Iuyen cdc, khi hda khi va che bien cac san pham u se xuat hien cac chat phat thai, dac biet la kim loai nang, xuat hien tLf cac ngudn khuech tan. Dieu nay gay khd khan cho viec xCr ly nudc thai khi van chuyen xi bang phUdng phap Udt.
2.2 Khi hoa b l n g phu'dng phap tang xoay
Cd Sd ky thuat
Vdi phUdng phap tang xoay hay tang sPi nhien lieu hat mjn dupc ludng khf, di chuyen tLf phfa dudi hudng len phfa tren, lam tdi rdi va nang len, cho den khi hinh thanh he hai pha khf- ran cd bieu hien nhu chat Idng.
Tien trinh hda khf vdi dxy va hdi nudc dupc dac trLfng bdi nhiet dp chuyen hda, phu thudc vao hoat tfnh cua loai than. Nhiet dp nay cang phai cao, khi kha nang phan Lfng cua loai than dupc sCf dung cang yeu. Vdi than nau nhiet 66 nay cd gia tri khoang 800°C, cdn vdi than da kem phan Lfng (kem hoat hoa) la 1050°C va hau nhu khdng phu thudc vao lupng dxy dua vao. Oe tao khf thi cac phUdng trinh phan ung khi hdi nudc va phan Lfng Boudouard ddng vai trd quan
trpng. Khf san pham chay dupc cd thanh phan chfnh la cacbon mdndxft va hydrd.
Trong qua trinh hda khf than, cac hat than bj dan tach ra, nen kha nang nhan tai giam di. Chung phan ra ra thanh cac hat bui va dUpc ludng khf day di. Trong vung phfa tren cua Idp xoay cho thay rang d loai than ua phan ung, thi mpt phan bui bay dupc chuyen hda nhd lUpng dxy thur cap d dang 'ddng bay'.
Cdng suat tinh theo the tich toan bd cCia Id hda khi thudng dao dpng giijfa 40 va 90m^/m^gid dd'i vdi than da va giufa 60 va 150m^/m^gid ddi vdi than nau. Cdng suat hda khf ty dd'i cd the dat tLf 1000 den 15000m^/m^gid ddi vdi than da va tCf 1000 den 25000m^/mlgid ddi vdi than nau, khi sCf dung cac id hda khi dac biet.
Pham vi ap dung
Nhieu ke't qua nghien CLfu va phat trien ky thuat cho thay kfch thUdc hat than hpp ly de cd the chuyen hoa toan phan nam trong khoang 0,8 den 5mm. Cac hat cd kfch thudc nhd hdn, dac biet la vdi trpng lupng the tfch nhd, cd thdi gian dLfng trong budng khf hoa ngan; cac hat cd kfch thudc Idn hdn lai khd day ndi (xoay), cd kha nang lang xudng trong Idp xoay va bj day ra ngoai cung tro than.
PhUdng phap nay cung thfch hdp cho loai than de phan Lfng (than nau).
Lfu diem cd ban cua phUdng phap hoa khf tang xoay la hau nhu loai bd dupc SLf xuat hien cua 'vung u'.
KHCNM* S 6 12/2008* CHE BI^N SLT DIJNG THAN
nghTa la trong san pham khf se cd ft thanh phan chat bdc.
Ngoai ra, cac thanh phan chat bdc dupc chia tach nhd phan Lfng hpp hydrd (hydrd hoa).
San phan khf cd tdi 70 den 80% CO va H2, hau nhU khong xuat hien cacbon hydro.
Nhupc diem chi'nh cua phUdng phap hoa khi tang xoay la cd lupng bui Idn trong khf va cd ham lupng cac bon cao trong xi lay ra tLf tang xoay.
Tac dong den moi tru'dng Khac vdi phUdng phap tang cd djnh, vdi phUdng phap tang xoay san pham 'u' xuat hien ft hdn ma v i n thudng phai tach ra khdi san pham khf, khi san xuat khf tdng hpp.
Tro than cua phUdng phap tang xoay van cPn cd thanh phan chay dUpc, cd the loai dupc thdng qua ddt tiep theo trong cac Id hdi, trong cac Id nung xi mang.
2.3 Phu'dng phap khi hoa dong bay
Cd sd ky thuat
Than dUpc nghien mjn d dang bpt bui, dupc thdi vao Id khi hoa cung vdi d xy va hdi nudc. Qua trinh chuyen hoa xay ra trong d6ng bay (d trang thai Id lilfng).
Hat than trong Id hoa khi dupc lam ndng nhanh bdi cac dong khi va qua trinh trao ddi nhiet va sau dd dUpc chuyen hoa vdi d xy. Chay mdt phan than se cung cap du nSng lupng can thiet cho phan Lfng thu nhiet.
Oe cho qua trinh chuyen hoa xay ra hoan toan can thiet dieu khien de cd tdc dp phan
ung nhanh. Nhiet dp phan ung de dap Lfng yeu cau nay len tren 1200°C. Trong dieu kien nhiet dp nay cac thanh phan cua tro than nhanh bj mem va vi vay phUdng phap hoa khf bang dong bpt than hau nhU lam viec vdi san pham loai ra la xi than.
Cdng suat tuyet ddi cua IP hoa khf nam trong khoang 360 den 440kg than tfnh cho 1m^
the tfch IP va trong 1 gid. Thdi gian luu lai cua cac hat bpt than trong Id khoang 0,6 den 0,9 giay.
Pham vj sur dung
Theo nhieu kinh nghiem khac nhau, than can dupc nghien mjn, vdi khoang 90%
cP hat dudi 0,1mm. Khi SLr dung than nau, kfch thudc hat cd the Idn hdn.
Do nhiet dp hoa khf cao, nen mac du thdi gian luu d trong Id ngan, than van dupc chuyen hoa hau nhU hoan toan, do vay trong tro hau nhu khdng c6n cac bon va dupc lay ra d the Idng (xi) mpt each de dang. Tuy nhien, ham lupng CO trong khf thanh pham se cao, cdn khf me tan, nhUa hac fn hoac cac cacbon hydrd chf cd ft.
Van de moi trUdng
San pham khf cd chCfa ft cacbonhydrd bac cao. Cd tdi 95% luu huynh trong than dupc chuyen hoa thanh H2S va COS d dang khf. Ty sd H2S/COS bang khoang 9:1. Vi vay can chu y den lupng thu hdi H2 trong khf vi cd phan Lfng tao HjS.
Cac thanh phan chCfa luu huynh thudng gay ra cac tac
dpng an mPn manh. Neu sCr dung giai phap rCfa sach khf, se thu dupc luu huynh d dang nguyen td, do vay khdng can tfnh den giai phap ch6n lap.
Thanh phan nitd trong than hau nhu dupc chuyen hoa toan bp sang the khf. Ngoai ra amPniac xuat hien ft. Bui c6 the tach ra bang cac bien phap lpc bui th6ng thudng.
2.4 Hoa khi than trong long dat
Hda khf than trong Idng da't, hay hda khf than tai via, hda khf than ngam
(LInderground Coal Gasification-UCG) la tien hanh
hda khf than ngay d via than.
Qua trinh hda khf dupc thuc hien qua cac cPng doan la:
bdm P xy vao via than, hda khf than va thu san pham khf len mat da't nhd cac IP khoan, khoan tU mat dat. San pham khf dupc SLf dung de san xuat dien, ddt ndng cdng nghiep hoac lam nguyen lieu cho c6ng nghiep hda chat.
Vi 66 tham thau cua cac via than thudng kh6ng Idn, nen can cd bien phap ndi th6ng hai 16 khoan vdi nhau va phai giilr dupc trong sudt qua trinh hda khi vung via than nam giUa hai Id khoan. Viec ket ndi cd the thUc hien bang cac IP khoan ngang, xien vdi ky thuat khoan da dUpc SLf dung trong khai thac dau khi (hinh 4).
PhUdng phap hda khi tai chd da dupc phat trien dau tien d Lien Xd cu trong nhCrng nam 1930 va dUpc SLf dung d mLfc dp thUdng mai trong chien tranh the gidi thCf 2. Mpt he thdng v i n dang dUpc SLf dung tai Uddbekistan.
KHCNM* S6 12 2008* CHE B I £ N SLfDUNG THAN
Thong tin khoa hpc cong nghe m o
Hai nudc OLfc va Bi cung da tien hanh thf nghiem tai hien trudng d dp sau 85dm vdi hai 16 khoan each nhau 35 m, dupc ndi bang Id khoan ngang. Nam 1950 d Anh cung da thu" nghiem thanh cdng d via than tai Newman Spiney, Derbyshire.
Khf hda than ngay tai via than dupc trien khai d quy mP Idn ke tU 1960 va cac so dd thCf nghiem da dupc danh gia d nhieu qudc gia, trong dd cd Trung Qudc, an Do, uc, Nam Phi, My va Anh. Cac nhu cau nay cung da va dang la dpng luc cho nhiing phat trien cPng nghe, cac ky thuat dieu khien an toan, phUdng phap thu gom va chPn lap CO2.
Tren hinh 5 phac hpa sd dd phat trien va Lfng dung cac he thdng hda khi tU Uddbekistan den viec ket hpp vdi cac cdng nghe lam sach khf ndng, nha may nhiet dien ket hpp khf va hdi nudc cung nhu chung cat dau tai My va Nam Phi.
Lfu diem cd ban cua phuong phap khf hda than tai via than la:
+ Khdng phai khai dao, van chuyen than va xiS ly tro than;
+ Khdng sCr dung nhieu dien tfch tren mat dat;
+ Khdng gay phat thai NO2 Nhupc diem cd ban la:
+ Khong the theo doi, dieu khien dupc mpi yeu td lien quan trong qua trinh khf hda than;
TU nhufng Uu va nhUpc diem tren cho thay khf hda than tai via se gay ra cac van de ve mPi trUdng, lien quan den van de 6 nhiem va riji ro:
+ Sap Id, sut lun den mat da't, + Phat tan khf ddt, nhUa than vao khdi da
+ Anh hudng den ngudn nUdc.
Tren hinh 6 phac hpa kha nang hinh thanh khoang trdng ngam va phat tan khf ddt vao khdi da vay quanh, la nhung qua trinh con khd dieu khien.
•*." •*.• •*." •*.' •*." •*." •*." •*.• •*.' •*.• •*." •*." •*." •"." A *
'^^J'J'J'.J./.^.i.J'.J'.J.i.^.^.J ^T^T^i^I^i^l^i^i^l^I^i^i^i^:^!
' ; • * . ' ' ; •*.' •*.' •".• ^ ; • * ; ' . * ' ; • ' ; ' ; • ' ; • ' ; • '.* •*.* •*." ^ . ' •*.*'." •*.' • * ; •*." •*." ••.• ^.* •*." •*.' ••
:<:<f!:<:<:f:-!i
: •".• '.* •".• <: •".• ••.' '.* ••.' •".''." '".• ^.* •".• '.* ^.' <: ^: <: < I-; ^ ' ^ ' ^; ^; ^ . - f ; J^; ^ . - ^.« <.• .f.• ^ • <_• ^ . ' ^ ; ^l
Hinh 4. Sa dd nguyen ly hda khi than tai via than My
he thdng hoat ddng
tCf 1984
UDOBE KISTAN
Hda khf than ngam (UCG)
Chu trinh ket hpp hda ktii IGCC
> ^
CO cac CO tua bin khac nhau
MAY PHAT DIEN
Hoat dong lien tuc tCr
1961
CO cac he thong v6i cong suat
>300W
Qua trinh chUng cat bun ^
NAM PHI SASOL san suat dau dieden va hda dau tu 40 nam
CAC SAN PHAM NHIEN LIEU L6NG
Hinh 5. Sado phat trien ky thuat, cdng nghe tCrmd hinh hda khi than ngam tai Uddbekistan
Ndi chung vung sap Id phu thupc vao nhieu yeu td khac nhau. Cac yeu td cd ban la:
The nam va chieu day via than
Cac tinh chat cd ly cua than va da vay quanh
Cac dac diem ve cau true dia chat cua khdi da vay quanh
KHCNM* S 6 12/2008* CHE BIEN SU DUNG THAN
Tren hinh 7 md phdng cac giai doan bien ddi trong khdi than, khdi da vay quanh trong qua trinh khf hda than.
3. Lfng dung phUdng phap hoa khi trong nha may nhiet dien
Hda khf than la qua trinh ra't da dang va phLfc tap, cho phep chuyen ddi than thanh san pham khf. San pham khf, sau khi dupc lam sach va khCr luu huynh, dupc dan den cac tua bin khf vdi chLfc nang la nhien lieu de san xuat dien. Khf ndng ra khoi tua bin khf lai dUpc dan den cac ndi hoi va san pham thu dupc la hdi nudc. Hdi nUdc dupc SLf dung de kfch hoat tua bin hdi nudc va cung lai san xuat dien.
Nhu vay mpt nha may nhiet dien kieu nay bao gdm cd he thdng tua bin khf, tua bin hdi va ndi hoi, cung nhU he thdng hda khf than, gdm budng hay Id hda khf va cac he thdng Ipc bui, khCf luu huynh, lam sach khf. He thdng nay dupc gpi la nha may dien khf va hdi. Ngay nay hda khf than thudng siJ*
dung phUdng phap cua hang Shell. Vdi phUdng phap nay cung cd the thay ddi chut ft de khf hda nhUa hac fn. Mpt phUdng phap khac la phUdng phap hda khf cua Texaco, tuy nhien chu yeu dupc sCr dung de khf hda nhua hac fn.
Mdt nha may dien nhU vay thudng dupc gpi la nha may dien lien hpp vdi he thdng khf hda tfch hpp (Intergrated Gasification Combine Cycle -IGCC).
Duong nhien sau he thdng
khong khi, hoac hdi
HLfdc va
6 xy
inhL/a than trong cac
khe niJt
* f L i u i i y i i y d i n V - ^ t - -
tdn that khf san phSm
Hinh 6. Md phdng cac qua trinh khd dieu khien khi hda khi than ngam
hda khf can thiet cd bp phan lam nha may nay cd hieu suat sLf sach khi de dam bao chat lupng
khf sao cho tua bin khf cd the van hanh dupc tdt.
Tren khap the gidi da xuat hien khoang 20 cd sd hiet dien, hoat ddng vUa mang tfnh thCr nghiem, vUa mang tfnh trinh dien vdi cdng suat tU 60 den 500MW, tuy nhien da phan la tai My. Cac
dung than dat khoang 45%.
Ngoai than, cac co sd nay cdn cd the SLr dung ca cac sinh khdi lam nguyen lieu hda khf. NgUdi ta du tfnh khoang 10 den 15 nam tdi se xuat hien cac co sd mang tfnh thUong mai. Tren hinh 8 la sd do nguyen ly mpt nha may dien hoat ddng theo md
Giai doan 3
Hinh 7. Md phdng dien bien qua trinh hda khi ngam.
KHCNM* S(") 122008* CHE BIEN SU DUNG THAN
Thong tin khoa hpc cong nghe mo
hinh IGCC.
Oe loai trU phat tan CO2 vao khong khi, da nay sinh cac phUdng an tach CO2 va chPn lap vao trong IPng da't. Sd d d nha may dien kieu nay the hien tren hinh 9. He thdng IGCC la thich hpp nhat ddi vdi kha nang tach c b z . Mpt he thdng theo mo hinh nay da bat dau hoat dpng nam 2006 tai My, vdi cdng suat 270MW dien va tach 9 0 % CO2. Tach CO2 trudc khi ddt khi cung lam giam dupc ca lupng khi khdi.
Tren cd sd cac sd dd phat trien nha may dien hda khf than, cac sd do nha may dien vdi chu trinh hoa khf ngam cung dupc de xuat Hinh 810 la sd dd mpt nha may dien sCr dung khf tU khf hda than tai via./.
Tai lieu tham khao Voges:
1. Klaus Klimafreundliche
Kraftwerkstechnologien der Zukunft. Siemens Energietag, Berlin 22.11.2005.
2. http://www.coal- ucg.com/current%20developments.
html: Underground Coal
Gasification Current Developments(1990 to date)
3. http://www.coal-ucg.com/:
Underground Coal Gasification-A clean coal process ready for commercialisation
4.http://www.clean- energy.us/index.php
5.http://www.coal.gov.uk/resour ces/cleanercoaltechnologies/ucgint ro.cfm
6.tittp://ec.europa.eu/dgs/energ y_transport/international/bilateral/in dia/energy/doc/eu_india_3/coal/wol f_bruining_underground_coal_gasif ication.pdf
7.http://www.fossil.energy.gov /international/Publications/
8.http://www.woridcoal.org/pa ges/content/index.asp?PagelD=4 25L..
TK: tach khong khi LSK: lam sach khi TuK: tua bin khi TuH: tua bin hdi nudc
Hinh 8. Sa dd nha may nhiet dien IGCC
thai,
hoa khi, lam sach khi
fo,
Tach khong
khi '•
-
chuyen hoaCO
V 1 k h i "
\J
-
)
Tach C O j
1
Tua bin khi, hdi nudc
^ C O j
Ni/dc
Hmh 9. Md hinh tach CO,
tach CO, Phat dien
Tach khong khi
lam sach khi r
Hinh 10. Sadd san xuat dien vdi he thdng hda khi than tai via
KHCNM* SO 12/2008* CHE BIEN SLT DUNG THAN
