MC LC CHNG I: M
U..............................................................................3
CHNG II: TNG QUAN L THUYT V CNG NGH............42.1.Nguyn l hot ng
chung..........................................................................................4
2.1.1.Nhit
................................................................................................................4
2.1.2. xo
trn:...........................................................................................................4
2.1.3.Thi gian:
.............................................................................................................4
2.2. Phn loi cc phng php
nhit.................................................................................4
2.2.1.Nhit
phn:............................................................................................................4
2.2.2.Thiu
t..............................................................................................................10
2.3.Nhin liu cho qu trnh
t.......................................................................................12
2.3.1.Nhin liu b sung cho qu trnh
t...................................................................12
2.3.2.Dng cht thi nguy hi lm nhin
liu...............................................................13
2.4.Lng khng kh
d...................................................................................................13
2.5.u v nhc im ca phng php
nhit.................................................................15
2.5.1.u
im...............................................................................................................15
2.5.2.Nhc
im:........................................................................................................15
2.6.Hiu qu qu trnh
t................................................................................................15
2.6.1.Hiu qu phn hy(DRE: destruction and removal
efficiency)............................15 2.6.2.Hiu qu t (CE
Combution
Efficiency)............................................................16
..........................................................................................................................................16
2.7.ng
dng....................................................................................................................17
2.8.Hin trng p dng phng php t Vit
Nam......................................................23 Trong
cuc kho st ca nhm nghin cu ti Vin KTN v BVMT phi hp vi S KHCN v MT
TP H Ch Minh thng 1/2002 ti 7 l t rc thi t tai khu vc pha Nam,
trong c 5 l t c ch to trong nc v 2 l t nhp ku t nc ngoi. Danh mc cc
loi l nh
sau:..........................................................................................231
CHNG III: CC THIT B S DNG TRONG PHNG PHP
NHIT.......................................................................................................243.1.L
t cht
lng..........................................................................................................24
3.1.1.Nguyn l hot
ng............................................................................................24
3.1.2.u v nhc
im...............................................................................................25
3.2.L t cht
rn............................................................................................................26
3.2.1.Phn
loi:.............................................................................................................26
3.2.2.Nguyn l hot ng ca l t cht thi nguy
hi..............................................28 3.3.Gii thiu mt
s dng l
t.....................................................................................28
3.3.1.L t thng
quay................................................................................................28
y l loi l t cht thi c nhiu ng dng bi qu trnh xo trn tt, t hiu qu
cao c s dng kh ph bin cc nc tin tin hin nay. M l t thng quay chim
ti 75% s l t cht thi nguy hi, l t tng si chim 10%, cn li 15% cc loi
l khc (l c nh t nhiu cp). L t thng quay cng c cu to gm hai bung t:
s cp v th
cp........................................................................................29
3.3.2.L t gi/v c
nh..............................................................................................31
3.3.3.L t tng
si.....................................................................................................31
3.3.4.L xi
mng...........................................................................................................34
3.3.5.L
hi..................................................................................................................34
3.4.Gii thiu mt s phng php x l
nhit................................................................34
CHNG IV: KT LUN V KIN
NGH.......................................384.1.Kt
lun......................................................................................................................38
4.2.Kin
ngh....................................................................................................................38
TI LIU THAM
KHO.......................................................................39
2
CHNG I: M UTrong qu trnh pht trin, cc hot ng sn xut kinh t sn
sinh ra mt lng ln cht thi, c bit l cc loi cht thi nguy hi. C rt
nhiu nh ngha v cht thi nguy hi v cc nh ngha ny u nhc n c im chung
ca cht thi nguy hi l chy n, n mn, hot tnh, c tnh. Ti Vit Nam, do
tnh a dng v s pht trin nhanh chng ca cc loi hnh cng nghip m lng cht
thi nguy hi c cc c tnh nh trn ngy cng nhiu. Lng pht thi cc cht ny
cng nhiu e doa nghim trng n mi trng v sc khe con ngi. V vy, cc loi
cht thi ny cn thit phi c x l trit . Do khng th x l cht thi nguy hi
theo cc phng php x l cht thi thng thng nn ngi ta nghin cu v v a vo
ng dng mt lot cc phng php chuyn dng x l cht thi nguy hi. Mt trong
cc phng php c ng dng nhiu trong thc t l x l cht thi nguy hi bng
phng php nhit. y l k thut x l cht thi nguy hi c nhiu u im hn so vi
cc phng php khc. Phng php ny dng x l cht thi nguy hi khng th chn lp
m c kh nng chy, n p dng cho tt c cc dng cht thi: rn, lng, kh.
3
CHNG II: TNG QUAN L THUYT V CNG NGH2.1.Nguyn l hot ng chung X l
CTNH bng phng php nhit l qu trnh s dng nhit chuyn cht thi sang dng
kh, lng v tro ng thi gii phng nng lng di dng nhit. t c hiu qu cao,
qu trnh phi tun theo nguyn tc 3T: nhit (temperature); xo trn
(turbulence); thi gian chy (time). 2.1.1.Nhit Nhit cn phi m bo phn
ng xy ra nhanh v hon ton, khng to Dioxin, t hiu qu x l ti a (>
11000C ). Nu nhit qu cao, lu lng kh sinh ra qu ln s nh hng n thi
gian lu kh trong bung th cp. iu ny s lm gim s tip xc gia khng kh v
kh gas, khi thi ra c mu en, nng cc cht nhim nh CO, THC trong kh thi
cao. Nu nhit khng cao, phn ng s xy ra khng hon ton v kh thi ra cng
c mu en. V vy nu nhit qu cao cng nh qu thp s nh hng n hiu qu chy.
2.1.2. xo trn: tng hiu qu tip xc gia CTNH cn t v cht oxy ha, c th t
cc tm chn trong bung t hoc ti gc nghing thch hp gia dng kh vi bec
phun tng kh nng xo trn. 2.1.3.Thi gian: Thi gian lu chy lu phn ng
xy ra hon ton. i vi l t nhit phn, m bo thi gian lu chy thch hp s
kim sot c ch nhit phn ti bung t s cp cp kh gas ln bung t th cp,
quyt nh hiu qu x l ca l t. Thi gian lu cn thit m bo t chy hon ton
ca mi cht khc nhau ph thuc vo bn cht ca cht b t nhit t. => Cc yu
t trn lin h khng kht vi nhau, khi nhit phn ng cao, xo trn tt th thi
gian phn ng gim vn m bo hiu qu chy cao. 2.2. Phn loi cc phng php
nhit 2.2.1.Nhit phn: 2.2.1.1.Phn ng nhit phn xy ra nh sau: Cht thi
cht bay hi (kh gas) + cn rc
Kh gas bao gm: CxHy, H2, COx, NOx, SOx, hi nc Cn rn gm: Cacbon c
nh, tro4
2.2.1.2.Nhim v ca cc bung t trong l nhit phn: a) Bung t s cp:
Trong l nhit phn, bung t s cp c nhim v nhit phn cht thi rn to kh
gas. Kh ny s cp cho bung th cp nh s chnh lch p sut gia bung s cp v
bung th cp Qu trnh t nhit phn ti bung t s cp din ra theo cc giai
on: Rc thot hi nc nhit phn t cn Cacbon tro
b) Bung t th cp: Bung th cp c nhim v nhn v t kh gas t th cp bao
gm hai bung: trn v t cui cng. Lung kh di dng cc ht mng cha t l phn
trm carbon cao. Lng carbon cha trong ht s c t chy hon ton khi i vo
bung trn. Kh thot khi bung trn, qua ca c mn chn v vo bung t cui
cng. Vn tc thp trong bung t ny m bo thi gian t chy hon ton cc thnh
phn. 2.2.1.3.Nguyn l c bn v cc b phn c bn ca l Cc l nhit phn c b
phn kim sot khng kh theo tng iu kin c th, hot ng trong ch : thiu
kh(bung t s cp), v d khng kh(bung th cp)
5
Hnh 1. S l nhit phn tnh t cht thi
6
2.2.1.4.Yu cu vn hnh l t
Hnh 2.S quy trnh vn hnh l t 2.2.1.5.Yu t nhit trong qu trnh t
nhit phn T thc ngim nhn thy rng, cht thi c thnh phn caosu v nha cao
th nhit phn mnh di 5000C Cht thi ca ngnh dy da v rc du kh c thnh
phn cht hu kh phn hy nn nhit nhit phn ca cc cht thi ny cao hn: 600
6500C =>Nguyn tc chn nhit nhit phn = T + 1000C. Nh vy nhit nhit
phn ti thiu ca mt cht l 3500C Trong : T l nhit phn hy ca mt cht
7
Hnh 3. gim khi lng theo nhit nhit phn ca PE
Hnh 4. gim khi lng theo nhit nhit phn ca Cao su8
Hnh 5. gim khi lng theo nhit nhit phn ca Pet 2.2.1.6.Yu t m n qu
trnh nhit phn Cht thi c em t nn c m W 30% m < 20% th nhit bung t
t l: nhit rc kh bt u nhit phn mnh + 500C m t 20 30% th nhit bung t
t l: nhit rc kh bt u nhit phn mnh + 750C m t 35 50% th nhit bung t
t l: nhit rc kh bt u nhit phn mnh + 1000C
=>Khi m cao th thi gian nhit phn thng ko di, nng sut t s
gim
9
900 Nhie o t 800 700 600 Nhie o0C t , 500 400 6 300 4 200 100 0
0 50 100 Thgian, phu i t 150 200 2 CH4 CO 12 14
10 CH4,CO, %
8
0 250
Hnh 6. S hnh thnh CH4 v CO trong qu trnh nhit phn 2.2.2.Thiu t
2.2.2.1.Nguyn l chung ca qu trnh t t l qu trnh oxy ha nhit cao bng
oxy khng kh. Bng cch t CTNH, ta c th gim th tch ca n n 80 90 %.
Nhit phi cao hn 850 o C. Sn phm cui cng l tro, CO2 , nc Qu trnh t
thc cht l qu trnh oxy ha kh trong xy ra phn ng gia cht t (cht thi
dng hu c) vi oxy trong khng kh (thnh phn ca khng kh ch yu l: 79%
nit v 21% oxy theo th tch) nhit cao Phn ng xy ra nh sau: Cht thi +
(O2 + N2) --------> Sn phm chy + Q (nhit) Sn phm chy: Bi, SOx,
NOx, CO, CO2, THC, HCl, HF, ioxins/Furans 2.2.2.2.Cc yu t nh hng n
qu trnh chy Qu trnh chy v cc cht nhim to thnh (sn phm chy) lin quan
cht ch ti thnh phn, bn cht ca cht thi c t, nhin liu s dng, iu kin t
nh: h s d khng kh (oxy), nhit t, tip xc v thi gian tip xc gia nhin
liu (hoc kh gas) vi oxy... Qu trnh chy ca cht thi rn bao gm 4 giai
an c bn sau: + Qu trnh sy kh (bc hi nc).10
+ Qu trnh phn hy nhit cht thi (hnh thnh kh gas). + Qu trnh phi
trn kh gas hoc cht t vi gi (khng kh) v s mi la. + Qu trnh chy dng
kh. Cc nguyn tc c bn ca qu trnh t chy l p dng nguyn tc 3T +
Temperature (nhit ) : nhit ca khng kh trc khi a vo l v nhit ca bung
t cao phn ng xy ra nhanh, chy hon ton. Nhit khng cao phn ng s khng
xy ra hon ton v sn phm kh thi s c khi en v cc cht nhim kh nh CO,
Hydrocacbon (THC) cao. iu ny lin quan ti hoc l do kch thc bung t qu
nh hoc lng khng kh cp vo qu d lm ngui bung t. + Turbulence (xo
trn): tng hiu qu tip xc gia cht chy v cht oxy ho, c th t cc tm ngn
trong bung t hoc ti cc van i chiu dng kh tng kh nng xo trn. + Time
(thi gian): thi gian tip xc phn ng oxy ho xy ra hon ton bng cch t
cc vch ngn nhm tng thi gian tip xc hoc kch thc bung t ln. Trong cc
l t kiu c, nhit thp theo cch t c in th cc im chy h, 4 giai on ca qu
trnh chy xy ra cng mt v tr v cng mt lc. Do s phi trn km nn chy khng
hon ton, hiu qu chy km, c nhiu bi cng cc cht nhim (CO, THC, ) ko
theo trong khi thi. khc phc nhc im trn hin nay ngi ta tin hnh t cht
thi trong l t nhiu cp, c bit vic ng dng cng ngh t nhit phn ci thin
c vn nhim mi trng ng k. 2.2.2.3.Thnh phn ha hc ca cht thi i vi cht
thi c em t cha cc thnh phn hu c cng c th c coi nh mt dng nhin liu.
Thc cht nhin liu l nhng vt cht m khi t chy th pht sng v ta ra mt
nhit lng no . Cng nh nhin liu, cht thi c t c th tn ti cc dng: rn,
lng hoc kh. i vi thnh phn nhin liu rn v lng thng c biu din di cc
dng: - Thnh phn hu c - Thnh phn chy - Thnh phn kh C h + Hh + Oh +
Nh = Cc + Hc + Oc + Nc + Sc = 100% 100%
Ck + Hk + Ok + Nk + Sk + Ak = 100%11
- Thnh phn s dng
Cd + Hd + Od + Nd + Sd + Ad + Wd =
100%
Thnh phn c bn ca nhin liu cng nghip (cht thi) bao gm: C+H+O+N+S
+A +W= 100%
Trong : C, H, O, N, S, A, W l hm lng phn trm trng lng ca cc
nguyn t cacbon, hydro, oxy, nit, lu hunh, tro, m trong cht thi.
2.3.Nhin liu cho qu trnh t 2.3.1.Nhin liu b sung cho qu trnh t Cht
thi hu c cn c mt nhit rt cao chy, nhng n cng dng mt lng nhin liu b
sung mi cho qu trnh chy. Mt s cht thi nguy hi, khi lng nhit cung cp
cho cht thi chy khng v vy cn b sung mt s loi nhin liu gia tng nhit
chy. Bng 1: Mt s nhin liu cho qu trnh t Cht thi Lng nhit c t
(Btu/lb) Du ha Benzen Toluen Hidro Axid axetic Methyl alcohol Ethyl
alcohol Nha thng Du m Giy Giy nu Tp ch Giy gn sng Lp bc cht do
18900 18210 18440 61000 6280 10250 13325 17000 15000 7975 7250 5250
7040 7340 7 7 35 7 7 50 55 52 0.0053 65.8 49.6 49.3 53.6 41.6 0.5
0.5 0.5 0 0.5 0 0 0 0 1.5 1 22.5 5 2.6 0 0 0 0 0 0 0 0 0 6 6 5 5 5
rng (lb/ft) Khi lng (lb/ft3) tro (%) m (%)
12
Giy cacton Rut lp xe Nha poliethylen Gi rch Du m ng vt Vi dnh
du
11330 1700 20000 8000 17000 11000
5 40 40-60 10 15 50 60 70 100 60
1 0.75 0 3
3.5 75 0 5 0
20-30
1
(Btu: n v o lng nhit ca Anh) 2.3.2.Dng cht thi nguy hi lm nhin
liu y l phng php tiu hy cht thi bng cch t cng vi nhin liu nhm tn
dng nhit cho cc thit b tiu th nhit. Lng cht thi b sung vo l t c th
chim 10 -25 % tng khi lng nhin liu. 2.4.Lng khng kh d Khi cht thi
chy th chng cn mt lng khng kh nht nh, khi sn phm cn li sau khi chy
khng cn cha oxi th y gi l qu trnh chy hon ton nhng iu ny khng th xy
ra trong qu trnh chy. L t lun phi duy tr mt lng khng kh d t c qu
trnh chy. chy c th ngi ta phi cung cp oxi qua 2 giai on: Giai on 1:
Khi ng cho qu trnh t
Giai on 2: Chy vi mt lng khng kh d, lng khng kh d ny s dng trong
l t iu khin nhit trong l v lng khng kh d ny dng hp th lng nhit pht
sinh khi c phn ng ph xy ra trong sut qu trnh chy
13
Hnh 7. Biu lng khng kh d
Hnh 8. Mi quan h gia nhit v lng khng kh d
Nhin liu CH43600 3500 3400
% th tch 50,0 30,0 7,5 6,0 4,0 1,0 1,5
C2H6 C3H8 N2 H2 CO CO2
Nhit (0F)
3300 3200 3100 3000 2900 2800 2700 2600 2500 2400 2300 2200 2100
2000 0
Gi s rng tn tht nhit l 2%
10 20 30 40 50 60 70 80 90 100
% kh d14
Hnh 9. nh hng ca lng khng kh d i vi nhit bng t 2.5.u v nhc im ca
phng php nhit 2.5.1.u im Phng php x l bng nhit rt thch hp cho x l t
b nhim bi cht thi nguy hi, c th tch cht nhim ra khi t ng thi lm sch
trit cht nhim. L mt phng php an ton cho mi trng nu c h thng x l kh
thi. Hiu sut x l tiu c cao > 99%. C kh nng gim 90 95% trng lng
cht thi trong thi gian ngn
C kh nng x l ti ch khng cn vn chuyn i xa, trnh c cc ri ro khi vn
chuyn Cn b tro sau khi x l chim t l rt nh (0,01% ). Thi gian x l
nhanh. Din tch cng trnh nh.
2.5.2.Nhc im: Chi ph u t ban u , chi ph vn hnh v cng nh chi ph
xy dng h thng x l kh thi tn km Khng p cho t nhim kim loi nng. Cu
trc t sau khi x l b ph hoi. Vic thit k, vn hnh l t phc tp
c bit qu trnh t c th gy nhim mi trng nu cc bin php kim sot qu
trnh t, x l kh thi khng m bo 2.6.Hiu qu qu trnh t 2.6.1.Hiu qu phn
hy(DRE: destruction and removal efficiency) L kh nng phn hy mt cht
hu c nguy hi kh phn hy nht trong mt hn hp cht thi. DRE= (W u vo W u
ra )* 100/ W u vo. W: Nng cht nhim. i vi cc hp cht dioxins/furans
theo quy nh ca M th DRE phi t gi tr 99.9999%15
2.6.2.Hiu qu t (CE Combution Efficiency) CE = ( CO2 CO)*100/ CO2
CO v CO2 l nng phn trm theo th tch trong kh thi kh iu kin chun 7%
hoc 9% O2 Hiu qu t CE phi t trn 99.9% Ch o kh thi: sau khi np rc vo
5 pht , o cho n khi kt thc m Kt qu tnh ton hiu qu chy ca mt s l t
nh sau: Bng 2.Kt qu o ti l t cht thi cng nghip Cng ty FORMOSA
Bng 3.Kt qu o ti l t cht thi cng nghip DNTN Thi Tun
Bng 4.Kt qu o ti l t cht thi cng nghip Cng ty AVENTOS(l nhp)
Bng 5.Kt qu o ti l t cht thi cng nghip Cng ty SYNGENTA(l
nhp)
16
2.7.ng dng Phng php nhit l quy trnh cui cng ng dng cho mt s cht
thi khng th ti ch, ti s dng hay d tr an ton trong bi chn lp. Phng
php thiu t ch s dng khi cht thi l cht c sinh hc, khng b phn hy sinh
hc v bn vng trong mi trng, l cht d bay hi v phn tn, cht thi cha cc
cht hu c nh halogen, ch, thy ngn, km, photpho, sunfua Mt s cht thi
khng c x l bng phng php thiu t l cc cht thi phng x, cht thi d gy n
Phng php nhit c s dng x l cht thi m khng th chn lp c. Bn kh v cht
thi rn nguy hi l nguyn liu cho cc qu trnh t trong l t.
a. Cht thi nhim du Cng vi s pht trin ca ngnh du kh trong nhng nm
qua, cht thi nhim du cng tng nhanh, y l cc cht thi nguy hi i hi phi
c bin php x l thch hp. ngun gc cht thi nhim du c th k n: T hot ng
tm kim, thm d, khai thc du kh. T cc kho cng xng du. T hot ng v sinh
sc ra tu du.
Trc y, Cng ty Sng Thu ti Nng thit k v xy dng h thng l t x l cn
du t hot ng v sinh sc ra tu du cng sut 700 tn/thng. L t gm 2 bung t
s cp (nhit t 7000C) v th cp (nhit t 1.1000C), c h thng lm ngui v x
l kh thi. Tuy nhin, khi i vo hot ng, kh thi t l t khng t tiu chun
mi trng, ng thi hiu sut t khng t tiu chun thit k. Nh my x l cht thi
Cng ty TNHH SX-TM-DV Mi trng Vit Xanh c a ch ti L N1, ng N8, khu
cng nghip Nam Tn Uyn, Bnh Dng c nh gi l mt trong nhng nh my x l cht
thi cng nghip, rc thi nguy hi hin i v ln17
nht Vit Nam hin nay (Trch li nhn xt ca Tin s Nguyn Trung Vit, ch
tch hi ng nghim thu cp php x l cht thi nguy hi - Cc Mi trng Vit
Nam) Din tch mt bng nh my: 12.000 m2. H thng qun l mi trng ca nh
my: t tiu chun ISO 14001:2004 H thng x l cht thi nhim du ca nh my
bao gm L t cht thi 2 cp:tiu hy cn du, cht thi nhim du. Cng ngh l t
Nhit tiu hy cht thi Cng sut tiu hy cht thi : Cng ha lin bang c. :
trn 1.3000C : 24 tn/ ngy cc thng s sau:
i km vi l t l cc h thng ph tr bao gm h thng x l khi v thu hi bi,
m bo kh thi ra mi trng t tiu chun mi trng Vit Nam. H thng x l ca
cng ty TNHH Sng Xanh Vng Tu bao gm: H thng x l v tn dng cn du (Cht
thi rn, lng, cn du) cng sut 06tn/ Ngy , L t cht thi rn, lng nhit ti
a 12000C, cng sut 0.5khi/1h , L t rc hu c cng sut 20khi/ ngy(2ci).
H thng x l cht thi nhim du, h thng l t thng quay CS750kg/h. b. Cht
thi nhim cc cht c hi nh thuc BVTV Phng php c x dng x l cc thuc bo v
thc vt v c thnh cc cht v c khng c hi nh: CO2, H2O v Cly thng l bin
php cui cng khi khng cn cch tiu hy no khc hu hiu v trit i vi thuc
bo v thc vt c c tnh cao, qu bn vng. Bn cht ca phng php l oxy ha
thuc bo v thc vt bng oxy khng kh nhit cao. Phng php ny c u im l x l
c trit cc thuc bo v thc vt cn tn lu trong bao b to thnh cc cht v c
khng c hi. Tuy nhin phng php ny i hi k thut cao, nhit tiu hy trn
1600 oC, cn oxy v thi gian tip xc, thi gian lu tr ti thiu l 2 giy,
cn c s tham gia ca cht xc tc. Vi cc bao b cha thuc bo v thc vt dng
v c, c cha thy ngn (Hg ) v cc kim loi nng, phng php ny khng c p dng
bi hiu sut x l thp. Cc l t s dng trong phng php ny l cc l nung xi
mng hoc l t c bit. Hin ti i vi iu kin Vit Nam, vic xy dng cc l t c
nh t tiu chun v cc yu cu k thut l rt kh khn. Cc bo v mi trng (B mi
trng ) kt hp vi Trung Tm Cng Ngh Mi Trng ( B Quc Phng ) th nghim p
dng cng ngh tiu hy cht bo v thc vt tn ng bng phng php thiu t trn h
thng l hai cp. cng ngh ny l s kt hp ca18
3 phng php, u tin l phng php ha hc nhm lm gim ti a c tnh ca thuc
bo v thc vt. tip l x l nhit tiu hy hon ton cc yu t c hi v thu nh th
tch1h cc cht gy nhim, v cui cng l b tng ha cc ha ct cn li.
Hnh 10. M hnh tiu hy thuc bo v thc vt
19
c. Rc dc phm, y t, thuc l Lng cht thi rn y t pht sinh trn phm vi
ton quc theo c tnh ca B Y T nm 2001 l khong 12500 tn/nm. S liu iu
tra ca B Y T cho thy, hin nay c khong 61 l t cht thi y t (CTYT ) c
lp t trn ton quc. Th tng chnh ph ch o B KHCN v MT phi hp vi B Y T
tin hnh thm nh cc l t CTYT theo yu cu v k thut, kinh t, mi trng.
Theo d tho bo co quy hoch tng th x l cht thi rn y t ti Vit Nam, tnh
n thng 9 nm 2003, ton quc c 47 l t ngoi nhp c lp t v vn hnh x l cht
thi y t nguy hi. trong , c 2 l t cng sut ln (200 kg/h v 1000 kg/h
)t bn ngoi khun vin bnh thuc trch nhim ca x ngip x l cht thi y t
(trc thuc URENCO) ti hai thnh ph H Ni v Thnh Ph H Ch Minh, cn li hu
ht l cc l t c cng sut nh (t 20 n 100 kg/h). S lng l t sn xut trong
nc l 14 l vi cng sut x l dao ng t 20 kg/h n 50 kg/h.20
C nhiu loi l t khc nhau c th dng thiu t RTYT nguy hi. L quay: c
th t nhiu loi rc khc nhau, t nhit cao v cng sut thng t 200 kg/gi tr
ln. L y tnh: nguyn l chy t trn xung, cht thi trong qu trnh t khng c
xo trn. Ph hp vi cng sut thp, t theo m. L t tng si: hiu qu t cao do
rc thi lun trng thi ng v tip xc trc tip vi tc nhn mang nhit l ct. L
nhiu y: dng thp, t 3 vng nhit tuy nhin cao nht l 990oC. Ph hp vi l
cng sut cao. L Plasma: l cng ngh tin tin nht hin nay. Trng nhit
Plasma c th t t 3.000 n 16.600oC phn hu hon ton rc thi y t thnh
nhng nguyn t c bn, an ton tuyt i cho mi trng. Tuy nhin gi thnh x l
qu cao: 3-8 USD/kg rc thi. => Nh vy mi loi cng ngh, thit b t u c
nhng im mnh v hn ch ca mnh. Vic la chn phng n ph hp ph thuc vo nhiu
yu t nh: La chn nhit t v cp t (1 hoc 2 cp), vn hi lu, tn dng ngun
nhit ca khi l; Thnh phn, tnh cht v lng rc cn t mi ngy; Nng lc u t,
ngun kinh ph v qui m u t; Trnh ca ngi s dng; Kh nng gia cng c kh,
ngun cung cp nguyn vt liu c chng...; Ngun nng lng tin v r nht (ga,
du, in...)
Bng 6.Tng hp kt qu o cc cht nhim trong kh thi t cc l t rc y t
khu vc pha Nam21
d. i vi cc cht thi khc nh: Cht thi dung mi Nha cao su, m cao su
Cht tha cha Halogen, ch, thy ngn Cht thi d bc hi v do d phn tn
Ngoi vic p dng cc phng php c hc, ha hc, x l nhitmt s nc nh Nauy,
Thy in, Nht Bn, Hn Quc nghin cu p dng phng php thiu t CTNN bng l
nung xi mng. Qua kho st ca Cc Mi Trng v D n VCEP cng mt s c quan
lin quan, phng php thiu t CTNH bng l nung xi mng c kh nhiu u im. L
nung cng tn dng c nhit nng t qu trnh thiu t cc cht thi nguy hi dng
hu c thay th tit kim mt phn nhin liu. Cng c th a vo l nung xi mng
mt lng nht nh cht thi dng v c tiu hy. Cc cht thi v c ny s tng tc
hoc kt hp nguyn liu ca xi mng v l thnh phn ph gia cho xi mng. L
nung clinke dng thiu t CTNH phi l loi l hin i m trong thit k tnh c
tnh n vic thiu t CTNH. Hu ht cc loi cht hu c dng rn hoc lng k
c22
cc cht thi c cha PCB u c th thiu t trong l nung clinke, tuy nhin
cc cht thi cn qua cng on ch bin thnh nhin liu, cht ph gia t tiu ch
nht nh trc khi a vo l clike. Vic thiu t CTNH trong l clinke c th p
dng cho rt nhiu loi cht thi nguy hi nh: cc dung mi hu c, du thi c
cha PCB, sn, keo dn, vecni, plastic k c PVC lp cao su. Qu trnh chy
trong l clinke s ph hy cu trc ca cc cht thi nguy hi, tro x cn li
tham gia vo thnh phn xi mng khng gy nh hng n cht lng xi mng.
2.8.Hin trng p dng phng php t Vit Nam Hin nay trong iu kin th trng,
Vit Nam m ca v bun bn vi tt c cc nc trn th gii, nhiu cng ty ch to
thit b nhit ni ting c mt ti Vit Nam. Ni n l t ngi ta ngh n ngay vt
liu c kh nng chu nhit cao l gch chu la. min Bc c nh my gch chu la
ng Anh H Ni, min Nam c nh my gch chu la Tn Vn ng Nai sn xut c cc
loi gch chu la c nhit t 1450 17000C Trc y, cc loi l t Vit Nam u nhp
t nc ngoi. Hin nay, Vit Nam ch to c mt s loi l t c cng sut nh(t 40
70kg/h, vi` chi ph 200 750 triu ng) dng t rc thi t ng dng v mt s
loi rc thi cng nghip vi gi ch bng 1/3 cc l t nhp khu Trong cuc kho
st ca nhm nghin cu ti Vin KTN v BVMT phi hp vi S KHCN v MT TP H Ch
Minh thng 1/2002 ti 7 l t rc thi t tai khu vc pha Nam, trong c 5 l
t c ch to trong nc v 2 l t nhp ku t nc ngoi. Danh mc cc loi l nh
sau: L Hoval, nhp t B, Cng ty Mi trng th TP H Ch Minh L rc thi y t
Entec - 100, TT Entec, bnh vin a khoa tnh Bnh Dng L t rc thi y t,
Vin MT v TN , TT y t Bn C u Ty Ninh L t Hoval A.G, nhp t Thy S, bnh
vin L Li TP Vng Tu L t rc thi y t, H Bch Khoa TPHCM, Bnh vin C Lao
Minh Bn Tre L t rc thi y t TSH - 20G, Cng ty Thi Sn, Bnh vin qun y
175 L t rc thi y t, Vin CHUD, TT lao v bnh phi Tin Giang
23
CHNG III: CC THIT B S DNG TRONG PHNG PHP NHITCu to chung ca mt l
t Khu vc nhn cht thi v bo qun cht thi B phn nghin v phi trn cht thi
B phn cp cht thi, bn, cht rn Bung t s cp Bung t th cp Thit b lm
ngui kh hay ni hi chy bng nhit d gim nhit H thng ra kh Qut ht ht kh
v khng kh vo l kh duy tr p sut m ng khi
Hnh 11. S h thng t x l cht thi 3.1.L t cht lng 3.1.1.Nguyn l hot
ng c dng t cc cht thi nguy hi hu c c th bm c, ngoi ra cn kt hp t cc
cht thi dng kh, bn mn. Cht lng s c phun vo l t di dng sng bi vi kch
thc git lng t 1m tr ln. Loi thit b ny thng c dng hnh tr nm ngang,
tuy nhin trong trng hp cht thi lng c hm lng cht v c cao th thit b c
dng thng ng.24
Hnh 12. S l t cht lng
Cc thng s thit k l t cht lng Cc thnh phn ha hc ca cht thi Nhit
chy nht ca cht lng Hot tnh n mn ca cht lng phn ng Kh nng polyme ha
Hm lng tro ca cht thi sau x l Nhit nng chy ca tro
3.1.2.u v nhc im 3.1.2.1.u im t c nhiu loi cht lng nguy hi Khng
yu cu ly tro thng xuyn Thay i nhit nhanh chng theo tc nhp liu Chi
ph bo tr thp 3.1.2.2.Nhc im Ch p dng c i vi cc cht lng c th nguyn t
ha25
Cn cung cp qu trnh chy c hon ton v trnh ngn la tc ng ln gch chu
la D b nght bc phun khi cht lng c cn 3.2.L t cht rn L t cht thi c
th c thit k theo 3 dng, ph thuc vo cch np liu: Cht thi c treo trn h
thng treo Cht thi c t trn li Cht thi c t trong bung t C rt nhiu dng
l t khc nhau nhng trong l t c s dng h thng treo c kh nng np liu cht
thi kh u. Nhng i vi cht thi nguy hi th thng c t trong bung t.
3.2.1.Phn loi: C nhiu loi l t, tuy nhin ph bin mt s loi l t sau: L
t thng quay L t 1 bc (t khi dng) L t 2 bung
Hnh 13. L t 2 bungkiu ngang
26
Hnh 14. L t 2 bung kiu ng L t nhiu bc Mc ch l t trit cht thi v
kh thi ra mi trng phi t tiu chun qui nh. Cht thi c t trong l c nhiu
bung t: bung t s cp v bung t th cp. Thm ch c mt s trng hp t cht thi
nguy hi kh phn hy, c mi th l t c th c ti 3 cp t (3 bung t). V sau
ny k thut t cht thi ngy cng c ci tin v k thut t cht thi nhiu cp c
kim sot kh ra i, ch yu l p dng nguyn l nhit phn trong t cht thi hay
ngi ta cn gi l l t nhit phn
Bung t s cp Ca np liu M t Ghi bc thang Ca ly tro
Bung t th cp
Ca Ghi trt V sinh
Hnh 15.L t nhiu bc27
ng khi
3.2.2.Nguyn l hot ng ca l t cht thi nguy hi C 2 qu trnh chnh din
ra trong l t : qu trnh nhit phn, qu trnh oxi ha (oxi d). Qu trnh
oxi ha gim nng cc cht nhim c trong kh thi ra. Cc loi l t: L 2 bung
t L c b phn iu khin khng kh Thng c qu trnh oxi ha v qu trnh nhit
phn
L t thng quay th ch c qu trnh nhit phn. i vi cc l t 2 bung t
thng c thit k trong giai on u nhit phn lm gim tc kh, v gim lng cc
vt cht nh b cun theo. Lng khng kh d s c s dng oxi ha khng kh trong
c bung s cp v bung th cp. L t 2 bung c dng ph bin trong t cht thi
nguy hi. Bung t s cp: nhit trong bung t s cp khong 705 815 0C.
Trong bung t ny th mt phn cc cht thi hu c d bay hi s b bay hi. Cc
cht thi kh phn hy nhit ti bung t s cp s chuyn sang bung t th cp.
Bung t th cp: bung t th cp rt cn thit cho qu trnh t cht thi nguy hi
v trong bung t s cp cht vn cha cung cp thi gian, nhit v s xo trn ph
hy cc hp cht hu c kh phn hy. Nhit trong bung t ny thng 1300 15000C.
Ti bung t ny cung cp nhit cc cht thi hu c bay hi m ti nhit th hon
thnh qu trnh oxi ha. Qa trnh oxi ha din ra ti nhit 980 1200 0C
3.3.Gii thiu mt s dng l t 3.3.1.L t thng quay 3.3.1.1.Nguyn l hot
ng Thng dng t cht thi rn, bn, kh v cht lng. Thit b thng c dng hnh
tr c th t nm ngang hay nghing mt gc so vi mt ngang hoc thng ng.
Thng thng c quay 0,5 1 vng /pht, thi gian lu ca cht thi rn trong l
t 0,5 1h vi lng cht thi rn np vo l chim 20%th tch l. Thit b l t
trong l c nhit ln ti 14000C, v vy c th phn hy c cht hu c kh phn hy
nhit. Kch thc l t thng quay thng nh sau: ng knh trong thng t 1,5
3,6 m, chiu di t 3 9 m. T l ng knh theo chiu di thng l 4:1.
28
y l loi l t cht thi c nhiu ng dng bi qu trnh xo trn tt, t hiu qu
cao c s dng kh ph bin cc nc tin tin hin nay. M l t thng quay chim
ti 75% s l t cht thi nguy hi, l t tng si chim 10%, cn li 15% cc loi
l khc (l c nh t nhiu cp). L t thng quay cng c cu to gm hai bung t:
s cp v th cp. L s cp: L mt tang quay vi tc iu chnh c, c nhim v o
trn cht thi rn trong qu trnh chy. L t c t hi dc vi nghing t (1
5)/100, nhm tng thi gian chy ca cht thi v vn chuyn t ng tro ra khi
l t. Phn u ca l t c lp mt bec phun du hoc gas km qut cung cp cho qu
trnh t nhin liu nhm t nng cho h thng l t. Khi nhit l t trn 8000C th
cht thi rn mi c a vo t. Giai an t s cp, nhit l quay khng ch t 800 -
9000C, nu cht thi chy to nng lng gi c nhit ny th b t phun du/gas t
ng ngt. Khi nhit h thp hn 8000C th b t t ng lm vic tr li. Bung t th
cp (bung t ph): y l bung t tnh, nhm t cc sn phm bay hi, cha chy ht
bay ln t l s cp. Nhit y thng t 950 1100 0C. Thi gian lu ca kh thi
qua bung th cp t 1,5 2 giy. Hm lng oxy d ti thiu cho qu trnh chy l
6%. C cc tm hng kh thi va c thi qua vng la chy ca b phn t phun du
va c xo trn mnh lit chy trit . Kh thi sau c lm ngui v qua h thng x
l trc khi qua ng khi thi ra mi trng. 3.3.1.2.u v nhc im u im p dng
cho cht thi lng v rn C th t ring cht lng v cht rn hoc c th kt hp t
chung c cht lng v cht rn Khng b nght g l do qu trnh nu chy C th np
cht thi dng thng hoc khi Linh ng trong c cu np liu Cung cp kh nng
xo trn v cht thi v khng kh cao29
Qu trnh ly tro lin tc m khng nh hng n qu trnh chy Kim sot c thi
gian lu ca cht thi trong thit b C th np cht thi trc tip m khng cn
phi x l s b gia nhit cht thi C th vn hnh nhit trn 14000C Nhc im Chi
ph u t cao Vn hnh phc tp Yu cu lng kh thu ln do tht thot qua cc khp
ni Thnh phn tro trong kh thi ra cao
A B C 10 10
Hnh 8.L t thng quay
2 1
D E
10
3
F G 4 7 6 11 5
Tun hon
Hnh 16. H thng thit b l t thng quay c x l khTun hon
9
3011 8 H 10
Ghi ch: A. Kh nhin liu B. Khng kh t C. Cht thi rn D. Khng kh
t
E. Khng kh lm ngui H. X b 3. Bng ti tro 6. Thp ra kh 9. ng
khi
F. Nc b sung
G. Dung dch NaOH 2. Bung t th cp v lng bi 5. Thit b ra kh
Ventury 8. Van 11. Bm tun hon
1. L t thng quay 4. Bung dp kh nng 7. Thit b tch lng 10. Qut
khng kh
3.3.2.L t gi/v c nh V c cu ging nh l t thng quay nhng khng c phn
di ng. Trong bung th cp, lng kh cung cp thng l 50 80% lng kh yu cu
so vi mc ch v cho hai qu trnh nhit phn v chy xy ra ng thi. Trong
bung th cp, sn phm ca qu trnh nhit phn v cht hu c bay hi c tip tc
t. Lng kh cn thit bung th cp t t 100 200% so vi lng kh yu cu theo l
thuy 3.3.3.L t tng si 3.3.3.1.Nguyn l hot ng c s dng x l cht thi
lng, bn, cht thi kh nguy hi Cht thi c a vo lp vt liu l ct, ht nhm,
cacbonat canxi. Qa trnh oxi ha nhit phn x ra trong lp vt liu ny
Nhit vn hnh ca thit b khong 760 870C v lng kh cp s c cp d so vi l
thuyt khong 25 150% Thuc loi l t tnh c lt mt lp gch chu la bn trong
lm vic vi nhit cao. c im ca thp l lun cha mt lp ct dy 40 50cm nhm:
Lp ct nhn nhit v gi nhit cho l t, b sung nhit cho rc t. Lp ct c gi
thi xo ng l cht thi rn b ti ra, xo ng theo nn chy d dng. Cht thi
lng khi bm vo l s bm dnh ln b mt cc ht ct nng ang xo ng, nh vy s b
t chy cn thnh phn nc s bay hi ht. Qu trnh t tng si: Gi thi mnh vo
di lp v c l nn gi s phn b u di y thp lm lp m ct cng cc ph liu rn,
nho u c thi ti, to iu kin chy trit . Khoang pha di thp (trn v phn b
gi), l khu vc chy s cp nhit bung t t 850 31
9200C, cn khoang pha trn phnh to hn l khu vc chy th cp c nhit
chy cao hn (990 11000C) t chy hon ton cht thi. Trong thp si cn duy
tr mt lng ct nht nh to mt lp m gi nhit n nh v h tr cho qu trnh si
ca lp cht thi a vo . Kh thi sau c lm ngui v qua h thng x l trc khi
qua ng khi thi ra mi trng. 3.3.3.2.u v nhc im u im C th t c 3 dng
cht thi rn, lng, kh Thit k n gin v hiu qu nhit cao Nhit kh d thp v
lng kh d so vi yu cu thp Hiu qu t cao do din tch b mt tip xc ln Lng
nhp liu khng cn c nh Kh nng cp nhit cho cht thi n nhit chy rt cao t
sinh ra bi Nhit chy n nh Nhc im Kh tch phn khng chy c Lp dch chuyn
phi c tu sa v bo tr C kh nng ph v lp m Nhit t b khng ch nu cao hn
8150C c kh nng b ph v lp m Cha c s dng nhiu trong x l cht thi nguy
hi
32
Hnh 17.L t tng si
V>9,0m/s
V < 9,0 m/s
10500C Th tch khi 180 m3
10000C
9900C
Th tch khi 310 m3 8500 9200C C V < 2,0 m/s
850 C V = 2,0 2,5 m/s
0
36.000 m3/h
54.000 m3/h
Hnh 18. L t tng si
33
3.3.4.L xi mng 3.3.4.1.Nguyn l hot ng V thc cht y l dng l t thng
quay. Tuy nhin trong l ny cht thi c s dng l nguyn liu cho qu trnh
nung Clanhke. 3.4.4.2.u im Tng t nh l t thng quay, nhng n c li hn l
tn dng c lng nhit pht sinh do qu trnh t cht thi
Hnh 19. L t xi mng 3.3.5.L hi i vi cc cht thi l nhit tr cao c s
dng l nhin liu cho l hi. Tuy nhin cn phi lu n vn x l cht thi ca qu
trnh t trnh vic hnh thnh cc sn phm ph l cc cht kh c hi
3.4.Gii thiu mt s phng php x l nhit Bng 7.Mt s phng php x l
nhit34
35
Qu trnh x l
t
Phun cht lng
Thiu t cht thi ly nhim
t tn dng nhit
L hi Cht n mn Hp cht cuanua x x x Dung mi halogen
Dungmiphihalogen Chthuccha Clo Cht hu c khc Cht thi nhim du PCBs
Cht bn kim loi Cht lngnhim bn hu c Cht c hot tnh ha hc cao x x Cht
thi ly nhim x t nhim bn x x x Cht lng x x Cht rn hoc bn x x x Cht
kh x x x x x x x x x x x x
L t tng si
L t thng quay
Cc qu trnh cng nghip x x x x x
x
x
x
x
x
x
x
x
Cht thi nguy hi
36
x
x
Dng cht thi
x
x
37
CHNG IV: KT LUN V KIN NGH4.1.Kt lun Nhm thc hin nghin cu v nguyn
tc hot ng, u nhc im ca phng php nhit trong x l cht thi nguy hi Tm
hiu nguyn l hot ng, u nhc im v cu to ca mt s dng l t ph bin Nghin
cu c hin trng x l cht thi nguy hi bng phng php nhit Vit Nam nh gi c
hiu qu chy ca mt s l t thng qua cc thng s nng cc cht kh thi sau qu
trnh chy 4.2.Kin ngh Hin nay, cc l t Vit Nam a s l nhp ngoi, mt s l
t c ch to trong nc th hiu qu t khng n nh. V vy, cn phi xy dng c cng
ngh vn hnh l t thch hp cho mi loi cht thi. lm c nh vy th cn xc nh
chnh xc v thnh phn v tnh cht cht thi t xy dng mi quan h gia tc ,
nhit vi thi gian nhit phn v t u t thm c s vt cht k thut tnh ton
thit k ch to l t ngay trong nc, gim chi ph u t ban u t gim c chi ph
x l cht thi nguy hi
38
TI LIU THAM KHO1.GS.TS.Lm Minh Trit TS.L Thanh Hi,2006 Gio trnh
qun l cht thi nguy hi NXB Xy dng - t trang 214 218 2.Nguyn Quc Bnh
2002 Nghin cu xc nh iu kin nhit phn nng cao hiu qu ca l t Tp ch lao
ng tng lin on Vit Nam ti nghin cu 3.Mc Graw hill Hazardous Waste
Management Page 741 - 811
39
