bg-cong nghe moi truong c hong

7/29/2019 BG-Cong Nghe Moi Truong C Hong

1/154

- 1 -

MC LCMC LC ........................................................................................................................... 1

PHN 1: CNG NGH X L KH THI................................................................ 3

CHNG 1. Nhng khi nim c bn.......................................................................... 3

1.1. Thnh phn, cu trc v tiu chun v cht lng mi trng khng kh ............... 3

1.2. Cc ngun gy nhim mi trng khng kh ......................................................... 6

1.3. Cc tc nhn gy nhim mi trng khng kh .................................................... 10

1.4. nhim th cp nh hng n kh hu ton cu .................................................. 16

CHNG 2. Cc gii php phng chng v x l nhim khng kh.................. 22

2.1. Gii php quy hoch .................................................................................................. 222.2. Gii php cch li v sinh ........................................................................................... 22

2.3. Gii php cng ngh k thut ................................................................................... 23

2.4. Gii php thng gi ...................................................................................................... 23

2.5. Gii php x l cht thi ngay ti ngun.................................................................. 26

CHNG 3. Cc phng php v thit b x l bi ................................................ 27

3.1. Khi nim chung v bi phn loi bi ................................................................... 27

3.2. Cc phng php x l bi ....................................................................................... 28CHNG 4. Cc phng php x l hi v kh c................................................ 45

4.1. Khi qut chung ......................................................................................................... 45

4.2. X l kh v hi bng phng php hp th ............................................................ 45

4.3. X l kh v hi bng phng php hp ph ........................................................... 50

4.4. X l kh v hi bng phng php thiu t ......................................................... 55

4.5. X l kh v hi bng phng php ngng t ......................................................... 58

PHN 2: CNG NGH X L NC THI ......................................................... 60

CHNG 5. Mt s vn c bn lin quan n nc thi.................................. 60

5.1. Ngun gc, lu lng v thnh phn nc thi .......................................................... 60

5.2. Mt s ch tiu nhim c trng trong nc thi ................................................. 65

5.3. Cc bin php k thut bo v ngun nc ............................................................. 67

CHNG 6. Cc phng php x l nc thi ....................................................... 69

6.1. Cc bc v phng php x l nc thi v bn cn trong nc thi ................. 69


2/154

- 2 -

6.2. S dy chuyn cng ngh x l nc thi .......................................................... 77

6.3. Cng trnh x l bn cn ......................................................................................... 100

CHNG 7. Cc v d x l nc thi..................................................................... 103

7.1. Qui trnh x l nc thi thnh ph ....................................................................... 1037.2. Qui trnh x l nc thi bnh vin ........................................................................ 104

7.3. Qui trnh x l nc thi cng nghip thuc da .................................................... 106

7.4. Qui trnh x l nc thi nh my giy.................................................................. 108

7.5. Qui trnh x l nc thi nh my bia .................................................................... 110

7.6. Qui trnh x l nc thi nh my ng .............................................................. 111

PHN 3: CNG NGH X L CHT THI RN.............................................. 113

CHNG 8. Ngun gc, phn loi cht thi rn th......................................... 113

8.1. i cng v cht thi rn ...................................................................................... 113

8.2. Ngun pht sinh, phn loi cht thi rn th ..................................................... 115

8.3. Lng cht thi rn th pht sinh ....................................................................... 117

8.4. Thnh phn ca cht thi rn .................................................................................. 118

8.5. Tnh cht ca cht thi rn ...................................................................................... 120

8.6. Cht thi rn nguy hi.............................................................................................. 124

CHNG 9. Thu gom, tp trung v vn chuyn cht thi rn ............................ 126

9.1. Thu gom cht thi rn .............................................................................................. 126

9.2. Chn tuyn ng thu gom vn chuyn................................................................. 130

9.3. Trm trung chuyn ................................................................................................... 132

CHNG 10. X l cht thi rn th .................................................................. 135

10.1. C s la chn phng php x l....................................................................... 135

10.2. Cc phng php x l cht thi rn .................................................................... 13510.3. Thu hi, ti ch v ti s dng cht thi rn th.............................................. 151TI LIU THAM KHO .............................................................................................. 135


3/154

- 3 -

PHN 1: CNG NGH X L KH THI

CHNG 1. NHNG KHI NIM C BN

1.1. THNH PHN, CU TRC V TIU CHUN V CHT LNG MI

TRNG KHNG KH

1.1.1. Thnh phn kh quyn

Kh quyn l hn hp ca khng kh kh v hi nc. Hi nc thng c

nh gi theo m (% ). Cn khng kh kh cha b nhim c thnh phn ch yu

khong 78% Nit, 21% Oxy v khong 1% cc kh nhim khc nh CO 2, CO, SO2,

NO,Nhng thc t thnh phn ca khng kh b thay i kh ln do cc hot

ng ca con ngi thi ra nhiu loi kh thi khc nhau trong qu trnh sn xut v

sinh hot nn hm lng cc cht nhim tng ln ng k, nh hng trc tip n

i sng con ngi.

1.1.2. Cu trc kh quyn

Kh quyn ca Tri t c c im phn tng r rt:

-Tng i lu (0-10km):l lp khng

kh st b mt Tri t. Cht lng

khng kh y s nh hng trc tip

n sc khe ca con ngi. Tng i

lu hu nh trong sut i vi bc x

sng ngn ca Mt Tri, nhng thnh

phn hi nc trong tng ny hp th

rt mnh tia phn x sng di t b mtt, t sinh ra s xo trn khng kh

theo chiu ng, hnh thnh ngng t

hi nc v xy ra cc hin tng my,

ma, gi, bo,... Tng ny chu s bc

x nhit t b mt tri t rt ln, nn

nhit s gim theo cao, khong

0,5-0,60

C/100m.

-60oC

Tng trung lu

Tng bnh lu

50km

10km

-100oC

1200oC

0oC

27oC Nhit (oC)

Tng i lu

90km

cao km

Tng nhit

Hnh 1.1.Phn tng kh quyn


4/154

- 4 -

- Tng bnh lu (10-50km):Tng ny tp trung kh nhiu hm lng kh ozon, hnh

thnh tng ozon, n hp th mnh cc tia t ngoi ca Mt Tri trong vng 220-

330nm, v th nhit khng kh dng li, khng gim na, n cao 20-25km li

bt u tng v t tr s khong 0o

C cao 50km.- Tng trung lu (50-90km): y cn gi l tng ion (tng in ly). Di tc dng

ca tia t ngoi sng cc ngn, cc phn t b ion ha:

O + h O++ e

O2+ h O2+

+ e

Trong tng ny nhit khng kh gim dn theo t l bc nht vi cao v

t tr s khong -100oC, nhit ca kh quyn thp nht cao khong 8590km.

- Tng nhit (>90km):y l tng trn cng ca kh quyn, khng kh rt long vi

mt phn t 1013phn t/cm3, trong lc mt bin c mt 5x1019phn t/cm3.

Nhit trong tng nhit s tng theo chiu cao v t tr s khong 1200oC cao

700 km.

1.1.3. n v o v tiu chun cht lng mi trng khng kh

a. n v o:

nh gi hm lng cht nhim trong mi trng khng kh ngi tathng xc nh khi lng ca cht nhim chim bao nhiu so vi khi khng kh.

V d: trong 1m3khng kh th cht nhim nhim s chim bao nhiu cm3.

- i vi cc kh nhim thng o bng n v phn trm (%), phn triu (ppm),

phn t (ppb), hoc cm3/m3, mg/ m3, mg/l,...

- i vi bi, thng xc nh trng lng ca n cha trong 1 m3khng kh, nn c

n v o l mg/ m3, g/ m3,..

b. Tiu chun cht lng mi trng khng kh :

Cc cht nhim trong mi trng s nh hng n i sng v sc khe ca

con ngi, do vy nhm m bo sc khe con ngi v bo ton cc h sinh thi, c

quan bo v mi trng qui nh cc cht nhim thi vo mi trng khng c

vt qu gii hn cho php, n c biu hin qua nng gii hn cho php, nng

ny thng c thay i cho ph hp vi iu kin pht trin kinh t x hi ca

tng khu vc.


5/154

- 5 -

Bng 1.1.Mt s gi tr nng gii hn cho php ca mt s kh nhim:

CHT NHIM

NNG TI A

(mg/Nm3)CHT NHIM

NNG TIA (mg/Nm3)

Ct A Ct BBi tng 400 200 Axetaldehyt 270

Bi cha Silic 50 50 Anilin 19

Cacbon oxyt 1000 1000 Benzen 5

Clo 32 10 Clorofom 240

Axit clohydric 200 50 Etylen oxyt 20

Nit oxyt (tnh theo NO2) 1000 850 Metanol 260

Hydro sunfua 7,5 7,5 Naphtalen 150

Dioxyt lu hunh 1500 500 Phenol 19

Flo, HF, hp cht ca Flo 50 20 Toluen 750

ng v hp cht ng 20 10 Styren 100

Km v hp cht km 30 30 Vinylclorua 20

Ch v hp cht ch 10 5 Vinyltoluen 480

Ngun: Trch QCVN 19: 2009/ BTNMT v QCVN 20: 2009/ BTNMTGhi ch:

- Mt khi kh thi chun (Nm3) l mt khi kh thi nhit 250C v p sut tuyt

i 760 mm thy ngn.

- Ct A quy nh nng ca bi v cht v c lm c s tnh gi tr ti a cho php

trong kh thi cng nghip i vi cc c s sn xut, ch bin, kinh doanh, dch v

cng nghip hot ng trc ngy 16 thng 01 nm 2007, vi thi gian p dng n

ngy 31 thng 12 nm 2014.

- Ct B quy nh nng ca bi v cht v v lm c s tnh gi tr ti a cho php

trong kh thi cng nghip i vi:

+ Cc c s sn xut, ch bin, kinh doanh, dch v cng nghip hot ng k

t ngy 16 thng 01 nm 2007.

+ Tt c cc c s sn xut, ch bin, kinh doanh, dch v cng nghip vi thi

gian p dng k t ngy 01 thng 01 nm 2015.


6/154

- 6 -

1.1.4. S nhim mi trng khng kh

S nhim mi trng khng kh l qu trnh thi cc cht nhim vo mi

trng lm cho nng ca chng trong mi trng vt qu tiu chun cho php,

nh hng n sc khe con ngi, cc ng thc vt, cnh quan v h sinh thi.Nh vy, cc cht nhim thi vo mi trng m nng ca chng cha

vt qu gii hn cho php, cha nh hng n i sng sn xut ca con ngi v

h sinh thi th c th xem l cha nhim mi trng.

Do vy, cn phi xc nh nng ca cc cht nhim trong mi trng ri

so vi tiu chun cho php xc nh mi trng b nhim hay cha, hoc

nhim gp my ln tiu chun cho php.

1.2. CC NGUN GY NHIM MI TRNG KHNG KH

1.2.1. Phn loi

Hin nay s nhim mi trng khng kh c th do nhiu nguyn nhn khc

nhau, chng rt a dng v kh kim sot. nghin cu v x l c th phn thnh

cc loi ngun nh sau:

* Theo ngun gc pht sinh:

-Ngun t nhin: do cc hin tng thin nhin gy nn.

-Ngun nhn to: do cc hot ng ca con ngi gy nn.

* Theo c tnh hnh hc:

-Ngun im: ng khi ca cc ngun t ring l, ca cc nh my,...

-Ngun ng: tuyn giao thng.

-Ngun mt: bi rc, h nhim.

* Theo cao:

-Ngun cao: Cao hn hn cc cng trnh xung quanh (ngoi vng bng rp kh ng).-Ngun thp: Xp x hoc thp hn cc cng trnh xung quanh.

* Theo nhit :

-Ngun nng: Nhit cao hn nhit mi trng xung quanh.

-Ngun lnh: Nhit thp hn hoc xp x bng nhit mi trng xung quanh.

Ch cn qua s phn loi nh vy l ta c th bit c qu trnh nhim ca

cc ngun gy ra i vi mi trng nh th no. Trn c s s c bin php hu


7/154

- 7 -

hiu nht x l v trnh c mc nguy him ca chng gy ra i vi cuc

sng ca con ngi.

1.2.2. Ngun nhim do thin nhin

Gi thi s tung bi t t b mt t vo khng kh, hin tng ny thngxy ra nhng vng t trng khng c cy ci che ph, c bit l cc vng sa mc,

chng c th mang cht nhim i rt xa, gy nhim cho c nhiu khu vc.

Nhng ni m thp s l mi trng thun li cho cc vi sinh vt pht trin

mnh, n khi tri kh hanh chng s pht tn theo gi vo mi trng ri thm nhp

vo c th ngi qua con ng h hp, gy ra cc bnh v da, mt v ng tiu ha.

Ni la hot ng mang theo nhiu nham thch v hi kh c t lng t

vo mi trng, c bit l cc kh SO2, CH4v H2S.

Rng b chy nhiu cht c hi bc ln v lan ta ra mt khu vc rng ln.

Nhng cht c hi l: khi, tro bi, cc hydrocacbon khng chy, kh SO2, CO

,

NOx.

S phn hy t nhin cc cht hu c, cc xc cht ng thc vt s to ra

nhiu mi hi v kh c i vi sc khe con ngi. Sn phm phn hy thng sinh

ra l H2S, NH3

, CO2

, CH4

v sunfua.

S pht tn phn hoa, bi mui bin, bi phng x trong t nhin,... u l

nhng tc nhn khng c li cho cuc sng ca con ngi v cc sinh vt.

Tng khi lng cht thi do thin nhin sinh ra l rt ln, nhng n thng

phn b u trong khng gian bao la nn nng ca n khng cao, v li con ngi

sng u th thch nghi vi mi trng t nhin , do vy s nh hng ca

chng i vi cuc sng ca con ngi l khng ng k, nhng cc hot ng ca

con ngi lm gia tng thm hm lng cht nhim vo mi trng th s nhhng s rt nghim trng.

1.2.3. Cc ngun nhim nhn to

Hu ht cc hot ng ca con ngi u to ra cht thi, cht nhim vo mi

trng, c bit l trong sinh hot, cng nghip v giao thng.

a. Ngun thi do sinh hot


8/154

- 8 -

Hng ngy con ngi s dng mt khi lng kh ln cc nhin liu t nh

than, ci, du, kh t un nu v phc v cho cc mc ch khc. Trong qu trnh

chy chng s tiu th oxy ca kh quyn, ng thi to ra nhiu khi bi, kh CO,

CO2,... Nhng cht thi ny thng tp trung trong khng gian nh hp (nh bp), sthot kh ra ngoi chm chp nn to ra nng ln trong khng gian sng ca con

ngi.

Ngoi ra, cc hot ng sinh hot ca con ngi cn to ra nhiu rc thi, thc

n hoa qu tha, l mi trng thun li cho cc vi trng gy bnh pht trin, trong

qu trnh phn hy s gy ra nhiu mi hi, chng c th pht tn vo mi trng theo

gi v vo c th ngi theo ng h hp.

V vy, trong sinh hot cn c bin php thng thong hp l, v sinh sch s

c mt mi trng sng trong lnh hn.

b. Ngun thi do giao thng vn ti

Vi s tin b ca khoa hc cng ngh, con ngi to ra nhiu thit b my

mc c gii, th hin bng nhng dng xe c nm np trn ng ph, chng chy

bng xng du nn sinh ra nhiu khi, cc kh CO, CO2, NO v HC ,... s nh hng

ny ph thuc ch yu vo cht lng ca xe c lu thng trn ng. Xng pha ch

cng l mt tc nhn nh hng rt ln n sc khe con ngi.

Khi xe lu thng trn ng ph s tung bi t t b mt ng vo mi

trng khng kh, iu ny ph thuc ch yu vo mc v sinh v s thng thong

ca ph phng.

Ngun giao thng c c im l pht tn theo dng tuyn, l ngun thp, nn

s nh hng ca n tp trung ch yu khu vc dn c hai bn ng ph, do vy

cn phi c bin php trng cy xanh ngn cn bt s pht tn cht nhim ti cccng trnh hai bn.

c. Ngun thi do sn xut cng nghip

Mt xu hng i ngc vi cht lng mi trng l qu trnh th ha, cng

nghip ha, l qu trnh gim bt din tch cy xanh v sng h, th vo l

nhng ngi nh cao tng, nhng nh my cng nghip vi cc ng khi tun thi nghi


9/154

- 9 -

ngt cc cht nhim khc nhau lm cho cht lng mi trng khng kh khu

th nh hng rt ln.

Cc cht thi ca khu cng nghip rt a dng, s nh hng ca chng n

mi trng cng khc nhau, do nghin cu th cn xt c th cho tng loi nhmy.

-Nh my nhit in: Thng dng than v du chuyn nhit nng thnh in nng

nn trong qu trnh chy thng sinh ra nhiu kh c v to ra mt lng tro bi ln

(khong 10-30 mg/m3). Cc bi than, cc bng ti ca nh my u l ngun gy

nhim nng. c im chnh ca nh my nhit in l c ng khi thi cao (80-

250m) nn s pht tn ca cht nhim c th i xa n 15 km, s nhim ln nht l

cch ng khi khong 2 n 5 km theo chiu gi.

-Nh my ha cht: Thng sinh ra nhiu loi cht c hi th kh v rn. Cc cht

ny khi pht tn trong mi trng c th ha hp vi nhau to thnh cc cht th cp

rt nguy hi i vi mi trng. Nh my t khi c ng khi thi cao (thng di

50m), ch yu thi qua ca mi, ca s v ca ra vo; cht thi c nhit thp nn s

nhim ch yu tp trung ti nhng khu vc ln cn nh my.

-Nh my luyn kim: Cc cht nhim sinh ra gm rt nhiu kh c (COx, NOx, SO2,

H2S, HF,...) v bi vi cc kch c khc nhau do qu trnh chy nhin liu, qu trnh

tuyn qung, sng, lc, p nghin,... Nhit kh thi kh cao (300-400 oC, c khi n

800oC hoc hn na), ng thi vi ng khi thi cng kh cao (80 - 200m) nn to

iu kin cho cc cht nhim khuch tn i ln v bay xa, gy nhim trong c mt

khng gian rng ln.

-Nh my vt liu xy dng: l cc nh my nh xi mng, gch ngi, vi, xng

b tng,... chng thng sinh ra nhiu khi, bi t v cc kh CO, NOx, SO2,... S nhim ca cc nh my ny ch yu ph thuc vo cng ngh sn xut, mc x

l cht thi trc khi thi vo mi trng; nhng hin nay c nhiu vng nng thn

cn tn ti nhiu l gch, ngi, vi vi cch thc t th cng nn gy nhim rt ln,

nh hng khng nh n sc khe con ngi v nng sut cy trng, vt nui khu

vc .


10/154

- 10 -

1.3. CC TC NHN GY NHIM MI TRNG KHNG KH

C th ni cc cht nhim trong mi trng tn ti rt nhiu dng khc

nhau, nhng c th c xp thnh 2 loi chnh sau:

-Kh: SOx, NOx, COx, H2S,... v cc hi c.-Rn : tro, bi, khi v cc Sol kh.

1.3.1. Cc kh gy nhim mi trng khng kh

a. Kh COx: (CO: cacbon monoxit; CO2: cacbon dioxit).

COx l kh khng mu, khng mi v khng v. Sinh ra do qu trnh chy khng

hon ton ca cc nhin liu c cha cacbon (than, ci, du):

C + O2 COx

- Vi CO : Tr lng sinh ra hng nm l 250 triu tn / nm. Hm lng CO trong

khng kh khng n nh, chng thng bin thin nhanh nn rt kh xc nh c

chnh xc.

Khi CO thm nhp vo c th ngi theo con ng h hp, chng s tc dng

thun nghch vi oxy hemoglobin (HbO2) tch oxy ra khi mu v to thnh

cacboxyhemoglobin, lm mt kh nng vn chuyn oxy ca mu v gy ngt:

HbO2

+ CO HbCO + O2

CO tc dng vi Hb mnh gp 250 ln so vi O2.

Triu chng ca con ngi khi b nhim bi CO thng b nhc u, tai,

chng mt, bun nn, mt mi. Nu b lu s c triu chng au u dai dng, chng

mt, mt mi, st cn. Nu b nng s b hn m, co git, mt xanh tm, chn tay mm

nhn, ph phi cp.

Thc vt t nhy cm vi CO, nhng khi nng cao (100 - 10.000ppm) s lm

xon l cy, cht mm non, rng l v km hm s sinh trng ca cy ci.- Vi CO2

: c li cho cy ci pht trin trong qu trnh quang hp nhng gy nn hiu

ng nh knh lm nng bu kh quyn ca Tri t.

b. Kh SOx: (SO2: Sunfua dioxit; SO3: Sunfua trioxit).

Ch yu l SO2, l kh khng mu, c v hng cay, mi kh chu. SO2trong

khng kh c th bin thnh SO3 di nh sng Mt Tri khi c cht xc tc.


11/154

- 11 -

Chng c sinh ra do qu trnh t chy nhin liu c cha lu hunh, c

bit l trong cng nghip c nhiu l luyn gang, l rn, l gia cng nng.

Hm lng lu hunh thng xut hin nhiu trong than (0,2-0,7%) v du

t (0,5-4%), nn trong qu trnh chy s to ra kh SO2:S + O2

SO2

Tr lng ca SO2 l khong 132 triu tn/ nm, ch yu l do t than v s

dng xng du.

SO2s kch thch ti c quan h hp ca ngi v ng vt, n c th gy ra

chng tc ngc, au u, nu nng cao c th gy bnh tt v t vong.

Trong khng kh SO2gp nc ma d chuyn thnh axit Sulfuric (H2SO4).

Chng s lm thay i tnh nng vt liu, thay i mu sc cng trnh, n mn kim

loi, gim bn sn phm dng.

Thc vt khi tip xc vi SO2s b vng l, rng l, gim kh nng sinh trng

v c th b cht.

c. Kh NOx: (NO: nitric oxit ; NO2: nit dioxit).

NOx thng xut hin nhiu trong giao thng v cng nghip. Trong khng kh

nit v xy c th tng tc vi nhau khi c ngun nhit cao > 1100oC v lm lnh

nhanh trnh phn hy:

N2 + xO2 2NOx

Tr lng NOx sinh ra khong 48 triu tn / nm (ch yu l NO2).

NO2l kh c mu nu, khi nng 0,12 ppm th c th pht hin thy mi.

NOx s lm phai mu thuc nhum vi, lm cng vi t, ni lng v gy han r

kim loi.

Ty theo nng m NO2m cy ci s b nh hng nhng mc khc

nhau:

- Nng khong 0,06 ppm c th gy bnh phi cho ngi nu tip xc lu di.

- Nng khong 0,35 ppm thc vt s b nh hng trong khong 1 thng.

- Nng khong 1 ppm thc vt s b nh hng trong khong 1 ngy.


12/154

- 12 -

- Nng khong 5 ppm c th gy tc hi n c quan h hp sau vi pht

tip xc.

- Nng khong 15 50 ppm gy nh hng n tim, phi, gan sau vi

gi tip xc.- Nng khong 100 ppm c th gy cht ngi v ng vt sau vi pht tip xc.

Vi NO2 l tc nhn gy ra hin tng khi quang ha.

d. Kh H2S:

H2S cn gi l Sunfur hydro, l kh khng mu, c mi trng thi.

H2S sinh ra do qu trnh hy cc cht hu c, cc xc cht ng thc vt, c

bit l cc bi rc, khu ch, cng rnh thot nc, sng h nhim v hm l khi

thc than.

Tr lng H2S sinh ra khong 113 triu tn / nm (mt bin 30 tiu tn, mt

t 80 triu tn, sn xut cng nghip 3 triu tn).

H2S c tc hi l gy rng l cy, thi hoa qu v gim nng sut cy trng.

i vi con ngi, khi tip xc vi H2S s cm thy kh chu, nhc u, bun

nn v mt mi. Nu tip xc lu s lm mt kh nng nhn bit ca khu gic, t

tn hi n h thn kinh khu gic v ri lon n kh nng hot ng bnh thng

ca cc tuyn ni tit trong c th, cui cng dn n bnh thn kinh hong ht tht

thng. Ngoi ra n cn kch thch tim p nhanh, huyt p tng cao khin nhng ngi

mc bnh tim cng nng thm.

- nng 150 ppm s gy tn thng n c quan h hp.

- nng 500 ppm s gy tiu chy v vim cung phi sau 15-20 pht tip xc.

- Nu nng cao (700-900ppm) n c th xuyn qua mng ti phi, gy h

m v t vong.e. Kh Ozon:

Ozon c k hiu l O3, n l sn phm ca cht cha oxy (SO2, NO2v

andehyt) khi c tia t ngoi ca Mt Tri kch thch:

NO2 NO+ O

O + O2 O3


13/154

- 13 -

Ngoi ra, di tc dng ca tia t ngoi Mt Tri chiu vo phn t O2s phn

tch chng thnh nguyn t oxy (O), cc nguyn t oxy ny li tng tc vi phn t

O2 to thnh O3: O2

+ h O + O

O + O2 O3Ozon sinh ra v mt i rt nhanh, n ch tn ti trong khong vi pht. Ozon tp

nhiu cao 25 km (tng bnh lu), nng khong 10ppm. Cn st mt bin,

nng ozon ch khong 0,005 - 0,007 ppm.

Ozon c tc dng to thnh l chn ngn cn tia t ngoi ca Mt Tri chiu

xung Tri t, iu tit kh hu ca Tri t, trnh gy nn nhng nguy hi i vi

i sng ca con ngi v cc sinh vt. Nhng nu nng ozon trong kh quyn qu

ln s gy nhim ozon v s nh hng trc tip n sc khe ca con ngi :

- nng 0,02ppm cha c tc ng gy bnh r rt.

- nng 0,3ppm mi v hng b kch thch, cm thy rt.

- nng 1-3ppm gy mt mi sau 2 gi tip xc.

- nng 8ppm gy nguy him i vi phi.

Ngoi ra O3cn nh hng ti qu trnh pht trin ca cc thc vt (c bit l

cy c chua, u,...), chng thng gy ra bnh m l, kh ho mm non.

Bn cnh ozon cn gy tc tc hi n cc loi si bng, si nilon, si nhn

to v hng mu thuc nhum, lm cng cao su.

Nu ozon qu cao cng s tham gia vo qu trnh lm nng ln ca Tri t,

khi nng ozon tng ln 2 ln th nhit trung bnh ca Tri t tng ln 1oC, gy

nh hng n kh hu ton cu.

f. Kh CxHy:

L hp cht ca hydro v cacbon (mtan, tylen, anilin,...).L kh khng mu, khng mi.

Sinh ra do qu trnh t chy nhin liu khng hon ton, c bit l ti cc nh

my lc du, khai thc v vn chuyn xng du, s r r ng ng dn kh t,...

Ty vo hp cht ca chng m to ra cc cht nhim khc nhau v gy ra

nhng tc hi khc nhau:


14/154

- 14 -

-tylen (C2H4): gy bnh phi cho ngi, lm sng ty mt, c th gy ung th

phi cho ng vt. N cn lm vng l cy v cht hoi cy trng.

- Benzen (C6H6): N thng c dng trong k ngh nhum, dc phm,

nc hoa, lm dung mi ha tan du m, sn, cao su, lm keo dn dy dp. Trongxng c t 5-20%. Khi benzen thm nhp vo c th theo h hp s gy ra bnh thn

kinh, thiu mu, chy mu rng li, suy ty, suy nhc, xanh xao v d b cht do

nhim trng mu.

g. Ch (Pb) v cc hp cht ca ch:

Ch xut hin nhiu trong giao thng v c s dng xng pha ch (khong 1%).

N l cht lng, bc hi nhit thp, c mi thm.

Ngoi ra, trong cng nghip luyn kim, n lot, sn xut pin, cng nghip ha

cht,... cng gy nhim ch rt ln.

Ch thm nhp vo c th ngi gy tc hi n no, thn, huyt qun v cng

nng to mu ca c th, thm ch nh hng xu n c quan sinh dc v kh nng

sinh sn ca con ngi, c bit l cc ph n mang thai, ch c th lm yu thai nhi,

d b sy thai.

Nguy him nht l cc tr em, nu b nhim c ch s nh hng n tr tu,

sinh ra bnh ng ngn v n gy c tnh i vi no. i vi ngi ln b nhim c

ch cng mc cc bnh thiu mu, vim thn, cao huyt p, thm ch c th vim thn

kinh trung ng v vim no.

h. Kh NH3 :

NH3cn gi l amoniac, c trong khng kh di dng lng v kh. L kh

khng mu, c mi khai. Sinh ra do qu trnh bi tit ca c th, qu trnh phn hy

cht hu c, trong mt s cng ngh lnh s dng mi cht NH3, ti cc nh my snxut phn m, sn xut axit nitric,...

nng 5-10ppm c th nhn bit c amoniac qua khu gic.

Tc hi ca amoniac ch yu l lm vim da v ng h hp. nng 150-

200ppm gy kh chu v cay mt. nng 400-700ppm gy vim mt, mi, tai v

hng mt cch nghim trng. nng 2000ppm da b chy bng, ngt th v t

vong trong vi pht.


15/154

- 15 -

Ngoi ra, amoniac nng cao s lm l cy trng bch, lm m l v hoa,

lm gim r cy, lm cy thp i, lm qu b thm tm v lm gim t l ht ging ny

mm.

1.3.2. Bi v sol khBi c sinh ra trong giao thng, cng nghip, hm l khai thc than v c

bit l trong mt s cng ngh sn xut c s dng cc nguyn vt liu sn sinh ra bi.

Nhng ht bi kch thc ln c kh nng gy chn thng bn ngoi c th nh da v

mt, nhng ht bi nh (100m c th lng ng ri xung t di tc dng ca lc trng

trng.

Bi c nhiu loi khc nhau, chng c hnh dng, kch thc v thnh phn

khc nhau nn s gy nh hng khc nhau i vi cuc sng ca con ngi. C th

k ra mt tc hi ca mt s loi bi nh sau:

*Bi silic: Gy nguy hi i vi phi, gy nhim c t bo li du vt x ha cc

m lm gim nghim trng s trao i kh ca cc t bo trong l phi. Cng nhn

trong cc ngnh cng nghip khai thc than, khai thc , c gang, phun ct,... rt d

b mc bnh phi nhim bi silic.

*Bi aming: Cc ht bi aming thng c dng si, kch thc di ( 50m), n s

gy x ha l phi v lm tn thng trm trng h thng h hp. Ngoi ra n cn c

kh nng gy ung th phi.

*Bi st, bi thic: Gy nh hng phi nh hn cc loi bi khc, n lm m phim

chp phi bng tia X-quang. Bi ny khi i vo d dy c th gy nim mc d dy,

ri lon tiu ha.

*Bi bng, bi si lanh: Thng gy bnh h hp mn tnh, xut hin nhiu nngdn trng bng, cng nhn khai thc, ch bin bng, cng nhn ngnh si dt. Bi c

c tnh gy d ng. Triu chng ban u ca bi l gy tc ngc, kh th nhng

chng qua khi sau mt thi gian nu ngng lm vic. Nu tip tc lm vic tip xc

vi loi bi trn th s suy gim chc nng h hp dn n tn thng nghim trng.


16/154

- 16 -

*Bi ng: gy bnh nhim trng da, bi tc ng cc tuyn nhn lm cho da b kh

gy ra cc bnh da nh trng c, vim da. Loi bnh ny thng cc th l hi, th

my sn xut xi mng snh s hay b nhim phi.

*Bi nha than: di tc dng ca nng lm cho da sng ty bng, nga, mt sng, chy nc mt, gy chn thng mt, vim mng tip hp, vim mi mt.

*Bi kim, bi axit: c th gy bng gic mc, li so, lm gim th lc, nng hn

c th m.

* Bi vi sinh vt, bi phn hoa: Thng ma ma ti cc cng rnh, sng h thot

nc, bi rc... l nhng ni l tng cho cc vi sinh vt pht trin mnh, nhng n

khi nng kh chng s pht tn theo gi vo mi trng khng kh v con ngi h

hp phi s gy ra nhng trn dch gy bnh nht nh, c bit l cc bnh v mt v

ng tiu ha. Ngoi ra, s pht tn phn hoa cng l nguyn nhn gy ra cc bnh d

ng ngoi da, bnh mt,... hin tng ny thng xut hin mt s nc c rng

cy m hoa ca n khng thch ng cho mi trng sng ca con ngi.

trn l tc hi ca mt s loi bi i vi sc khe ca con ngi, ngoi ra bi cn

nh hng trc tip n thm thc vt, chng bm vo l cy, lm cy mt kh nng

quang hp, gim nng sut cy trng. Mt s loi bi cn gy cht cc t bo l cy,

lm cho cy kh vng v chy. Bi cn lm tng nhanh qu trnh bo mn cc chi tit

my mc, thit b trong qu trnh hot ng, lm h hng cc sn phm v dng

cn thit ca con ngi,...

1.4. NHIM TH CP NH HNG N KH HU TON CU

1.4.1. Ma axit

Khi ngnh cng nghip pht trin th trong khng trung s xut hin nhng trn

ma axit, l nc ma c pH thp (< 5,6) lm cho nc c v chua nh dm.Nm 1948, cc nh khoa hc Thy in qua kho st cc trm quan trc nc

ma trong kh quyn pht hin ra nhng trn ma axit. Nm 1981 thnh ph Trng

Khnh (Trung Quc) cng xut hin ma axit, xt nghim cho thy nng trong

nc ma l 4,6; thp nht l 3. Chng nh hng nghim trng n cy trng v cc

cng trnh l thin.


17/154

- 17 -

S d c ma axit l v trong cc hot ng sn xut v sinh hot ca mnh, con

ngi t nhiu than v du m, trong khi thi c cha sunfua ioxit (SO 2) v

nit oxit (NOx). Hai loi kh ny khi gp nc ma hoc hi m trong khng kh s

tng tc vi nc to thnh axit v gy ma axit:SO2

, NO2

,... + H2O H2SO4

, HNO3

,...

Thng thng, nu kh quyn hon ton trong sch, khng b nhim bi cc

kh SO2, NOx th pH ca nc ma khong 5,6 - tc l thuc vo axit do kh

CO2trong kh quyn tc dng vi nc ma theo phn ng:

CO2+ H2O H2CO3

H+

+ HCO3

-

H2CO3cn gi l axit cacbonic, l loi axit yu, phn ng trn l thun nghch

vi nng axit trong nc ma ph thuc vo nng CO2trong kh quyn.

Khi ma c nng pH 4,5 bt u c tc hi i vi c v thc vt. Khi

pH nh hn na th ma axit gy tc hi nguy him i vi ngi, ph hy cn bng

sinh thi, gy thit hi cho ma mng, ph hy rng v hy dit s sng.

Ty c ma axit lm thit hi 8% din tch rng vo nm 1982 v 34% vo

nm 1983.

Chu u, vo nm 1988 theo s liu theo di kho st trn 26 khu rng th c 22

khu b thit hi 30%, s cn li thit hi trn 50%. Tnh chung ton Chu u c n 50

triu ha rng b h hi - chim 35% din tch rng ton chu lc. Rng Ty-Nam Trung

quc b ma axit gy thit hi rt nng, c ni t l cy cht ln ti 90%. tnh H

Nam ma axit lm ma mng b tht thu v thit hi c tnh ln n 260 triu USD.

Canada c hn 4000 h nc b axit ha, cc sinh vt trong h u cht ht,

nn cc h nc gi l "h cht".

Ngoi ra, ma axit cn gy n mn v hy cc bc tng i, cc cng trnh thk ngoi tri gy thit hi rt nng n. Ngi ta cn gi l hin tng "mt dn"

cc di tch lch s. Hin tng ny thng do axit sunfuric, v n c kh nng n mn

rt mnh, c th bo mn cc lp vi theo phn ng:

H2SO4+ CaCO3

H2O + CO2

+CaSO4

Phn ng ny sinh ra thch cao nhng n tan trong nc ma v chim ch

nhiu hn vi.


18/154

- 18 -

Vi nhng tc hi nh vy i hi cc nc trn th gii phi c bin php

gim cc cht nhim gy ma axit. C th thng 11-1988 khi th trng chung

Chu u EEC a ra mc tiu ct gim lng pht thi SO2t cc nh my nhit in

xung cn 57% mc pht thi nm 1980 cho n nm 2003 v kh NOx xung 30%cho n nm 1988. Mc ct gim pht thi SO2

ca tng nc thnh vin EEC

c xc nh ph thuc vo mc gy nhim xuyn bin gii ca nc , trnh

pht trin cng nghip, thnh phn lu hunh trong ngun nhin liu a phng v s

n lc trong vic kim sot nhim c p dng trc nm 1980.

1.4.2. Hiu ng nh knh

Trong cc hot ng ca con ngi thiu t rt nhiu nhin liu c cha

cacbon, in hnh l sinh hot, cng nghip v giao thng. Tnh tng khi lng CO 2sinh ra do t nhin liu l khong 2,5x1013

tn/nm. Ngoi ra, hot ng ni la hng

nm sinh ra lng CO2bng khong 40.000 ln CO2

hin c. Ton b CO2

sinh ra

khng phi lu ng mi trong kh quyn m n c cy xanh v bin hp th i

khong mt na. Phn CO2do bin hp th c ha tan v kt ta trong bin. Cc

loi thc vt di bin ng vai tr ch yu duy tr s cn bng CO2

gia kh quyn

v b mt i dng.Cn lng CO2

lu tn trong kh quyn, thc vt hp th tn ti v pht

trin, nhng khi hm lng CO2qu cao s l nguyn nhn gy ra hin tng hiu ng

nh knh.

Hin tng ny l do trong kh quyn c cha nhiu CO2, CH4

, N2O , CFC v

O3. Nhng thnh phn ch yu vn l CO2(xem hnh v).

CO2, 55

%

CH4, 15

%

N2O, 6

%

CFC, 7%CFC11+12

, 17%


19/154

- 19 -

y l nhng cht gn nh trong sut i vi tia sng ngn nn tia bc x Mt

Tri d dng i qua xung vi Tri t (v bc x Mt Tri l tia sng ngn),

nhng cc cht ny li hp th rt mnh cc tia sng di phn x t b mt Tri t

(tia hng ngoi), chnh v th Tri t ch nhn nhit ca Mt Tri m khng thotc nhit ra ngoi lm cho nhit trung bnh ca Tri t tng ln, ngi ta gi

l hin tng hiu ng nh knh, v kh CO2v mt s kh k trn c tc dng nh mt

lp knh ngn cn tia phn x nhit t Tri t.

Nhit tri Tri t tng ln l nguyn nhn lm tan bng cc Bc, nng

cao mc nc bin, lm trng ngp cc vng t lin ven b. Ngoi ra, khi nhit

tng cn lm tng cc trn ma, bo, lt, ng ngp gy rt nhiu thit hi cho cuc

sng con ngi.

Theo G.N.Plass: nu nng CO2trong kh quyn tng ln gp i th nhit

trung bnh ca Tri t tng ln 3,6oC.

Do vy, trnh c hiu ng nh knh i hi tt c mi quc gia cn phi

c bin php hn ch thi ra cc kh gy nh knh, c bit l kh CO 2.

1.4.3. Khi quang ha

Trong giao thng v cng nghip thng xut hin nhiu kh NO, n s phn

ng vi cc nhin liu khng chy ht, di tc dng ca Mt Tri s to ra cc cht

nhim th cp gi l "khi quang ha".

Cc phn ng trong khi quang ha rt phc tp, c th n gin ha nh sau:

NO2 NO + O

CH4+ 2O2

+ 2NO

H2O +HCHO + 2NO2.

CH4

+ O2

HCHO + H2O

O + O2 O3

O3+NO O2

+NO2

...

Theo phn ng dy chuyn nh vy s hnh thnh ra mt lot cc cht mi, sn

phm cui cng: NO2li sinh ra, NO mt i, O3

c tch ly, andehit, fomandehit,...

xut hin. Tt c cc cht tp hp li to thnh khi quang ha.


20/154

- 20 -

Khi quang ha thng gy cay, nhc mt, au u, rt c hng v kh th.

Ngoi ra n cn nh hng trc tip n thm thc vt, lm cho l cy chuyn t mu

xanh sang mu , xy ra hin tng rng l hng lot, cy b kh v cht. Khi quang

ha cn nh hng xu n hoa qu v cy lng thc, gy nhiu bnh tt cho gia sc,gia cm; cc mt hng cao su b lo ha rt nhanh, cc cng trnh kin trc b nhanh

chng ph hy,...

1.4.4. Hin tng thng tng ozon

Tng ozon c hnh thnh cao 25km (tng bnh lu), c tc dng chn tia

t ngoi ca Mt Tri chiu xung Tri t, che ch cho s sng loi ngi v cc

sinh vt.

Ngy nay, cng ngh lnh pht trin mnh, cht c s dng trong qu trnh

lm lnh l CFC, xut hin nhiu trong t lnh, my iu ha, x nghip ng lnh,

thy sn v trong cc dung dch ty ra, bnh cu ha,... N c nhiu dng F-11

(CCl3F), F-12 (CCl2F2),... Ni chung l cc hp cht c cha Clo. Khi r r v tht

thot ra ngoi, cc cht ny s khuch tn ln n tng bnh lu v b tn cng bi cc

tia cc tm ca Mt Tri v phn hy gii phng ra cc nguyn t Clo. Chnh cc

nguyn t Clo ny gy ra s suy gim tng ozon:

Cl + O3 ClO + O2

ClO + O3 Cl + 2O2.

Ngi ta c lng mi nguyn t Cl c th phn ng vi 100.000 phn t

ozon v gy thng tng ozon.

Tng ozon b thng s to iu kin cho tia cc tm ca Mt Tri chiu xung

Tri t, gy ra cc bnh ung th da v mt cho con ngi, nhiu loi thc vt khng

thch nghi vi tia t ngoi s b mt dn h min dch, cc sinh vt di bin s b tnthng v cht.

Ngi ta d on rng mt s suy gim 10% sc chu ng ca lp ozon mi

nm s sinh ra thm t nht 300.000 ca ung th lnh tnh, 4.500 ca ung th c khi u c

tnh v 1,6 triu ca c thy tinh th trn ton th gii. ngn chn nh hng ca

tng ozon b suy gim v ph hy, nhiu quc gia trn th gii, nht l cc nc pht

trin tham gia cng c Vin (22-3-1985) cam kt p dng mi bin php bo v


21/154

- 21 -

sc khe con ngi v mi trng khi nhng tc ng tiu cc do tng ozon b suy

gim, hp tc trong nghin cu, quan trc v trao i thng tin v lnh vc ny.

Tip l Ngh nh th Montral (Canada) v cc cht lm suy gim tng

ozon ODS c k kt ngy 16/9/1987 nhm xc nh nhng bin php cn thit cc bn tham gia hn ch v kim sot c vic sn xut v tiu th cc cht lm suy

gim tng ozon.

i vi Vit Nam, chnh thc tham gia v ph chun Cng c Vin v bo v

tng ozon v Ngh nh th Montral v cc cht lm suy gim ozon cng nhng sa

i b sung ca Ngh nh th vo thng 1-1994. Chng trnh quc gia v bo v

tng ozon ca Vit Nam nh sau:

- n nm 2005 ct gim 50% mc tiu th CFC so vi mc tiu th trung bnh

thi k 1995-1997.

- Nm 2010 s loi tr hon ton cht CFC.


22/154

- 22 -

CHNG 2. CC GII PHP PHNG CHNG V X L

NHIM MI TRNG KHNG KH

2.1. GII PHP QUY HOCH

Thc t cho thy nhiu nh my cng nghip nm ngay gia khu dn c v

th, gy ra nhiu bi, khi, ting n v cc cht nhim; nhiu ng khi nm ngay

u hng gi i vi khu dn c; trong cc khu ca con ngi cn m thp; s

thng thong, chiu sng khng m bo,... Tt c nhng nhc im l do cha c

bin php qui hoch hp l khi xy dng. Trc tnh hnh , hin nay nh nc yu

cu cc c s cn phi c s nh gi tc ng mi trng i vi cc c s c c

bin php khc phc; i vi cc cng trnh mi bt u c thc thi th cn phi bo

co nhng nh hng c th c i vi mi trng, phi m bo khng gy ra nhng

nh hng ln trong qu trnh xy dng v c qu trnh vn hnh, s dng sau ny.

Do vy, cn phi xem xt cc iu kin kh tng, a hnh v thy vn b tr

cc cng trnh cho hp l. Mt bng qui hoch phi m bo thng thong, n c

hng gi tt nht cho th. Bn cnh phi xt n s pht trin ca th trong

tng lai, cho cng trnh hin ti v tng lai khng nh hng ln nhau,...

2.2. GII PHP CCH LI V SINHThng cng gn ngun nhim th s nh hng ca n gy ra cng ln, do

vy cn phi qui nh vnh ai bo v xung quanh khu cng nghip, l khong cch

tnh t ngun thi n khu dn c. Khong cch ty thuc vo tnh cht v c

im ca tng loi hnh nh my, loi hnh sn xut gy nn, khong cch ny m

bo nng cht nhim khu dn c do ngun ny gy nn khng vt qu tiu

chun cho php.

Ngoi ra, i vi cc khu cng nghip cn c tng bao che hoc dng di cy

xanh ngn cn s pht tn bi v ting n trong khng gian, nhm gim ti a s

nhim mi trng n ni sinh sng ca con ngi.

Bng 2.1. Qui nh di cch ly v sinh theo cc cp c hi ca sn xut cng nghip:

Cp c hi I II III IV V

Di cch li (m) 1000 500 300 100 50


23/154

- 23 -

2.3. GII PHP CNG NGH K THUT

Cn phi hon thin cc cng ngh sn xut, s dng cng ngh tin tin hin

i, cng ngh sn xut kn, gim cc khu sn xut th cng, p dng c gii ha v

t ng ha trong dy chuyn sn xut.Gii php ny cn bao gm vic thay th cht c hi dng trong sn xut bng

cht khng c hi hoc t c hi hn, lm sch cht c hi trong nguyn liu sn

xut; v d tch lu hunh trong nhin liu than du, thay phng php sn xut kh

cc vt liu sinh ra nhiu bi bng phng php sn xut t, thay vic s dng than

du trong un nu bng in nng hoc nng lng Mt Tri, nng lng gi,...

Cc thit b my mc sn xut, cc ng ng vn chuyn cn phi kn, m

bo vn hnh an ton, kinh t v trnh s r r cht nhim ra ngoi mi trng.

2.4. GII PHP THNG GI

Nhim v ca thng gi l m bo trng thi khng kh cho con ngi sng v

hot ng ph hp vi tiu chun v sinh quy nh.

2.4.1. Cc s thng gi c bn

Trong mt phng kn ta c th thay i khng kh bn trong b nhim (do

nhit, do bi, do kh c) bng khng kh trong sch a t ngoi vo trong mt

khong thi gian nht nh (thng gi nh k) hoc trong mt thi gian khng hn

ch (thng gi thng xuyn). c gi l thng gi cho phng.

a .Thng gi chung:

Mc ch ca thng gi chung l a khng kh t ngoi vo vi lu lng cn

thit nhm pha long cng nhim (bi nng, bi, hi hoc kh c) trong ton

b khng gian nh xng, sau thi ra ngoi.

c thc hin trong phng m ngun c hi phn b u (trng hc, nhht, bnh vin) hoc nhng phng m khng on trc c ngun c hi s xut

hin v tr no (ca hng n, qun gii kht, cu lc b.)

H thng thng gi chung c nhc im l ni khng c c hi cng b nh

hng ca ngun c hi ni khc trn qua.

b. Thng gi cc b:

c thc hin thi trc tip cht c hi t ngun pht sinh ra ngoi (ht cc


24/154

- 24 -

b) hoc l thi khng kh sch vo cc v tr cn thit v bit trc (thi cc b).

Vic t chc, x l hp l cc cht gy nhim phi tho mn cc yu cu sau:

- Khng cn tr thao tc cng ngh.

- Khng cho khng kh cha cht nhim i qua vng th.- Vn tc thu kh ln.

Hnh 2.1.Thi cc b Hnh 2.2. Cu to t ht

Tu theo iu kin thc t, trong mt cng trnh c th va kt hp thng gi

chung va thng gi cc b.

c. Thng gi s c:

l s thay i nhanh chng th tch khng kh trong phng b nhim

khi nh hng n sc kho ca cng nhn v tc hi n sn xut. Trong thng gi

s c thng dng h thng thng gi p sut m (ch c ht ch khng c thi) m

bo kh c hi khng b lan to ra ngoi. Thit b pht hin v x l thng t ng

(cc r le kch thch nng c hi, cc rle ni mch in) hoc ng m h

thng bng tay.2.4.2. Phn loi h thng thng gi

Ngi ta cn c vo s chuyn ng ca khng kh phn loi. Thng c

hai loi: thng gi t nhin v thng gi cng bc.

a. Thng gi tnhin:

S chuyn ng ca khng kh t trong nh ra ngoi nh (hay ngc li) l do

chnh lch nhit bn trong v bn ngoi. T ch chnh lch nhit dn ti chnh


25/154

- 25 -

lch p sut v lm cho khng kh chuyn ng.

- Hin tng gi la: Khng kh vo nh v ra khi nh qua cc khe h ca ca v

qua cc l trn tng khi c gi thi c gi l gi la. Hin tng gi la u khng

khng ch c lu lng, khng iu chnh c vn tc gi v hngginn cn c gi l thng gi t nhin v t chc.

- Thng gi tnhin c tchc: Xc nh c din tch ca gi vo, din tch gi ra

xc nh c lu lng thng gi cho phng -> iu chnh c vn tc hng gi

l hin tng thng gi t nhin c t chc. Thng gi t nhin c t chc c

ngha rt ln v mt kinh t v khng tn km thit b, khng tn in nng nhng vn

gii quyt tt vn thng gi. V vy, Vit Nam c p dng rt nhiu c bit l

trong cc phn xng nng c nhit tha v trong cc nh cng nghip mt tng.

- Thng gi trng lc: l h thng thng gi t nhin di sc y ca trng lc hay

cn gi l thng gi ct p l thng gi t nhin bng mng dn c p dng trong

cc nh dn dng v cng cng. Khng kh chuyn ng trong mng dn do chnh

lch p sut ca ct khng kh bn trong v bn ngoi nh. Thng dng thng gi

cc ng khi ca cc nh gia nh.

Hnh 2.3.Thng gi t nhin trong nh dn dng v cng nghip

b. Thng gi cng bc (thng gi ckh)

L h thng thng gi hot ng a khng kh t trong phng ra ngoi (hay

ngc li) nh tc ng ca my qut v ng c. Thng c cc loi sau:


26/154

- 26 -

- Ht c kh: Ht khng kh b nhim, ht nhit, ht bi t cc ngun pht sinh

a ra khi phng m bo iu kin v sinh cho mi trng gi l ht c kh.

- Thi ckh: thi khng kh trong sch vo nh ti cc v tr cn thit v bit trc

tng cng hiu qu lm mt cho ngi cng nhn.- Hthng iu ho khng kh: Trong h thng thng gi c kh c y cc thit b

x l khng kh m bo yu cu ca con ngi v yu cu cng ngh gi l h

thng iu ho khng kh. Cc thit b bao gm: thit b lc bi, thit b sy nng,

lm lnh, lm m khng kh

2.5. GII PHP X L CHT THI NGAY TI NGUN

Cc cht nhim trc khi thi ra ngoi mi trng theo ng khi th ngi ta

cho chng i qua cc thit b x l gim nng cht nhim trnh cht thi c

nng vt qu tiu chun cho php. Cch lp t thit b nh hnh sau:

Hnh 2.4. Lp t thit b x l.

1- Ngun thi cht nhim.

2- Chp ht cht nhim.

3- Thit b x l cht nhim.

4- Qut khng kh vn

chuyn cht nhim trong

ng ng.

5- ng khi thi.

Cht nhim trc khi i vo thit b x l s 3 c khi lng l G1(mg/h) v

sau khi ra thit b x l c khi lng l G2 (mg/h), lc hiu sut ca thit b s l:

=

100(%)

i khi ngi ta c th xc nh hiu sut x l cht nhim theo cng thc sau:

=

100(%)

Trong yu

, ycui

l nng cht nhim ban u v sau khi qua thit b x l.


27/154

- 27 -

CHNG 3. CC PHNG PHP V THIT B X L BI

3.1. KHI NIM CHUNG V BI PHN LOI BI

3.1.1. Khi nim chung v bi

Bi l cc phn t cht rn, th ri rc c to nn do cc qu trnh nghin,

tn, p, dp hay do qu trnh ngng kt hoc do cc phn ng ha hc to ra.

Di tc ng ca cc dng khng kh chng chuyn thnh cc trng thi l

lng trong mi trng hay ri t do nh sc ht ca lc trng trng.

Bi l h thng gm hai pha: pha kh v pha rn ri rc. Cc pha rn ri rc

gm nhng ht c kch thc khc nhau (tn ti dng rn, lng).

Cc sol kh cng l h thng cc ht vt cht ri rc v n chuyn ng Braotrong mi trng. Tc lng chm ca cc sol kh rt b.

Vn tc lng chm ca cc ht bi vc l vn tc ri ca cc ht bi trong mi

trng tnh di tc dng ca lc trng trng.

3.1.2. Phn loi bi

a. Da vo c ht, ng knh ca ht bi phn loi

- Bi th: c 75,nhng ht c kch thc nh ht ct, sn, bi than,

- Bi: cc ht c = (5-75), thng c hnh thnh trong qu trnh hot ng ca

cc ngnh c kh, v d: mi, tn,

- Khi: = (1-5), gm cc ht vt cht (rn, lng) to ra do qu trnh t chy

nhin liu.

- Khi mn: gm cc ht vt cht rt mn c 1.

- Sng: cc ht cht lng, 10.

b. Da vo ngun gc pht sinh- Bi hu c: bi ng, bi go, bi bt m.

- Bi v c: bi kim loi, bi , bi t.

c. Da vo nguyn nhn hnh thnh

- Bi t nhin: Do qu trnh t nhin gy ra, do ng t, ni la v qu trnh khuch

tn bi phn hoa trong khng kh.

- Bi nhn to: Do qu trnh nhn to: bi c to ra do cc hot ng ca con ngi


28/154

- 28 -

d. Da vo tnh cht, ngun gc m xm nhp vo c th.

- Bi c 0,1 m: khi ht vo phi, b c quan h hp chn li (mi), khng nh

hng n h h hp.

- Bi c = (0,1-5) m: l bi nguy him nht, khi ht vo ng li trong phi (60-90)%, nh hng trc tip n sc khe con ngi.

- Bi c = (5-10) m: ht vo trong phi c phi o thi ra.

- Bi c 10m: khng vo h thng h hp c nhng gy tc hi i vi mt v

da.

3.2. CC PHNG PHP X L BI

3.2.1. X l bi bng phng php kh

a. X l bi bng bung lng bi

- Cu to:

+ Bung lng bi c dng hp

c tit din ngang ln hn nhiu ln so

vi tit din ng ng dn kh, khng

kh vo 1 u v ra u kia.

+ Bung lng bi c lm t

gch, b tng ct thp, hoc thp.

- Nguyn tc hot ng:

Da vo c s lc trng trng lng cc ht c kch thc tng i ln

bng cch gim vn tc dng kh v bi khi vo bung lng, cc ht bi do c khi

lng (c trng lc P) nn khi vn tc gim cc ht bi s tch ra khi dng kh vlng li. Kh sch c a ra ngoi.

- c im:

+ Hiu sut lc bi thp: = 40-60%, c p dng lng bi th c kch

thc ht ln t (60-70)m.

+ Thng s dng cp lc s b hoc nhng ni iu kin mi trng khng

kht khe.

Hnh 3.1.Bung lng bia) Mt ct dcb) S khng gian


29/154

- 29 -

- u, nhc im:

+ u im:

Chi ph u t ban u, vn hnh thp

Kt cu n gin

S dng trong x l kh c nng bi cao cha cc ht bi c kch

thc ln c bit t ngnh cng nghip luyn kim, nu chy kim loi.

Tn tht p lc qua thit b thp.

Vn tc kh i trong thit b thp nn khng gy mi mn thit b.

Gp phn lm ngui dng kh trc khi thi ra mi trng hoc dn qua

cc thit b thu bi k tip.

+ Nhc im:

Phi lm sch th cng nh k.

Cng knh, chim din tch, cn c khng gian ln khi lp t.

Ch c th thu c nhng ht bi c kch thc tng i ln

Khng th thu c bi c bm dnh v dnh t.

- Bin php nng cao hiu qu bung lng bi:

+ S dng bung lng

phn tng: ngha l chia

bung lng ra thnh nhiu

tng bng nhau, c th phn

tng theo chiu dc hoc

chiu ngang.

+ C th to ra cc

vch ngn trong bung lngkt hp bung lng vi cc

thit b lc bi kiu qun tnh

lc bi.

+ Tng chiu di v chiu rng bung lng.

- Phm vi p dng:

+ p dng lng bi th c kch thc ht t (60-70)m.

Hnh 3.2.Mt s bung lng bia)Bung lng bi nhiu tngb) Bung lng c tm chn

a)

b)


30/154

- 30 -

+ Do hiu sut thp nn thng c s dng cp lc s b hoc nhng ni

iu kin mi trng khng kht khe.

b. X l bi bng thit b lc bi kiu ly tm

C hai loi: Thit b lc bi ly tm kiu nm ngang v thit b lc bi ly tmkiu thng ng.

* Thit b lc bi ly tm kiu ng:

- Cu to:

Thit b gm 2 hnh tr lng vo nhau, hnh tr ngoi c bc kn, hnh tr

trong hai u rng.

1. ng dn kh v bi vo

2. Thn ca thit b

3. Cn

4. ng x bi

5. ng dn kh sch ra

6a,6b. Van x bi

- Nguyn tc hot ng:

Kh v bi c a vo theo phng tip tuyn vi thnh bnh (b mt hnh

tr ngoi) v thc hin chuyn ng xoy t trn xung di. Bi c khi lng m

theo qun tnh va p vo thnh bnh nn mt ng nng v ri xung di. Khng khsch i chiu v theo hnh tr nh bn trong chuyn ng ngc ln trn ra ngoi.

- u, nhc im:

+ u im:

Kh v bi i vo theo phng tip tuyn vi thnh bnh nn lc xoy li

tm ln do hiu sut lc bi t: = 60-80%. Lc c cc loi bi

c kch thc va v tng i ln.

Hnh 3.3.Xyclon ng


31/154

- 31 -

Kh v bi i ngc chiu nhau nn hiu sut x l cao.

Ch to n gin, vn hnh d dng, c th sa cha thay th tng b

phn.

C th lm vic nhit cao (n 500

o

C), lm vic tt p sut cao Hiu qu khng ph thuc vo s thay i nng bi.

Chim t khng gian lp t nn thng c s dng nhiu trong thc

t.

+ Nhc im:

Hiu qu x l km i vi bi c kch thc nh hn 5 m.

Tr lc ca dng kh ln nn ng c phi ln do chi ph vn hnh

cao.

Khng th thu c bi c tnh kt dnh.

- Bin php nng cao hiu qu cho xyclon:

+ tng hiu sut lc bi ngi ta thng dng xyclon chm.

+ Cc xyclon chm c th c ghp ni tip v song song vi nhau

- Phm vi p dng:

+ Xyclon thng c s dng lc tro bi trong kh thi l hi, l nhit in.

+ C th dng cp lc th, lc va, lc tinh.

* Thit b lc bi ly tm kiu ngang:

- Cu to:

Hnh 3.4. Cu to ca thit b lc bi ly tm kiu nm ngang

1. ng hnh tr bn ngoi; 2. Li hnh tr hai u bt trn v thon;

3. Cnh hng dng; 4. Khe hnh vnh khn; 5. ng loa; 6. Van iu chnh.


32/154

- 32 -

- Nguyn tc lm vic

Kh v bi c a vo thit b. Di tc dng ca l hng dng to ra

chuyn ng xoy ca dng khng kh v bi theo phng tip tuyn. Lc ly tm sn

sinh t dng chuyn ng xoy tc dng ln cc ht bi v y chng ra xa li hnh trri chm vo thnh ng bao v thot ra qua khe hnh vnh khn ri vo ni tp

trung bi. Khng kh sch theo ng loa thot ra ngoi.

- c im:

Lc li tm sinh ra ph thuc vo l hng dng, nu l hng dng to vn tc

dng kh ln th lc ly tm sinh ra mnh do vy hiu sut lc s cao hn. Ngc li,

nu l hng dng to vn tc dng kh nh th lc ly tm sinh ra yu do vy hiu sut

lc thp.

- u, nhc im:

+ u im:

Cu to thit b n gin

+ Nhc im:

Kh v bi i cng chiu vi nhau nn hiu sut lc bi khng cao, ch

nhng ht bi to mi b vng ra ngoi.

L hng dng d gy, lc li tm do l hng dng gy ra nh.

Tn nhiu din tch lp t do thit b nm dc theo chiu kh v bi vo.

- Phm vi p dng:

Do nhng nhc im trn m xyclon kiu nm ngang t c s dng trong

thc t.

c. X l bi bng thit b lc bi kiu mng lc (ti vi, li lc bi)

* Nguyn l chung:Dngkhvbicchnlibimnghoctilc;ti(mng)nyccc

khe (l)nhchoccphntkhiquaddngnhnggilicchtbi.Khi lp

bi dyngncn lngkhiqua thngi ta tinhnh runghoc thingc

thuhi bivlmschmng.

* Thng c hai hnh thc lc bi kiu mng lc l li lc bi v lc bi bng ti

vi.


33/154

- 33 -

* Li lc bi:

- Cu to:

+ Li c lm bng thp an, ty thuc

vo mc x l m chn kch thc li ankhc nhau.

+ Hp li (li thp hai bn) gia l cc

vt liu lc bi.

- c im:

+ Hiu sut lc bi rt cao: = 80-90%.

+ Lc c cc ht bi c kch thc t nh n ln.

+ Khi nng bi qu ln, bi bm nhiu, th phi thng xuyn lm v sinh

thit b.

- Bin php nng cao hiu qu li lc bi:

+ S dng li c bi du nhn s gip tng hiu qu lc bi ln cao hn : =

90-95%.

- Phm vi p dng:

+ Li lc bi thng c s dng lc sch bi trong khng kh thi vo

ca h thng thng gi, iu ha khng kh nh vi nng bi ban u khng qu

5mg/m3.

+ Li lc du thng c s dng cc nh my nhit in.

* Lc bi bng ti vi (ng tay o)

- Cu to: (Hnh 3.6)

+ Thit b gm nhng ti vi dt

t cc loi si khc nhau c lng vokhung li ng bng thp bo v v

a s c trang b c cu gi bi.

+ ng knh tay o c th khc

nhau, ph bin nht l 120-300mm,

khng vt qu 600mm.

+ C hai loi: lc t pha trong v

lc t pha ngoi.

Hnh 3.5.Li lc bi

Hnh 3.6. S thit b lc bi kiu ti vi


34/154

- 34 -

- c im:

+ Hiu sut lc bi cao: = 90-95%.

+ Thi gian lm vic theo chu k thng ngn.

+ Cn c vo nhit khi thi chn loi vi lm ti:Nhit khi thi > nhit mi trng: loi vi lm ti thng l vi

aming hoc li thp.

Nhit khi thi < nhit mi trng: loi vi lm ti thng l vi

thng thng.

+ Kh v bi vo thit b phi kh trnh tnh trng lm g thit b.

- Phm vi p dng:

Thit b ny ch c s dng nhng ni cn thu hi nhng loi bi qu c

gi tr hoc nhng ni yu cu cht lng mi trng cao.

d. X l bi bng thit b lc bi kiu tnh in

* Nguyn tc lc bi bng tnh in:

Tch in m cho ht bi, bi s mang in tch m, khi bi i qua b mt c

in tch dng, bi s b ht vo b mt ny, trung ha in v ri xung. Thit b

s dng dng in mt chiu vi in th cao (khong 50.000V).

* Thng c 2 hnh thc lc bi tnh in: lc bi bng in kiu ng v lc bi

bng in kiu tm.

* Thit b lc bi bng in kiu ng

- Cu to:

1. Dy kim loi ngn, tit din b,

mang in tch (-)

2. ng kim loi, mang in tch (+)

3. i trng cng dy 1.

4. Thit b cch in

5. Phu cha bi

Hnh 3.7. Cu to thit b lc bi

tnh in kiu ng.

5


35/154

- 35 -

- Nguyn tc hot ng:

Kh v bi c a vo thit b. Di in th cao m dy kim loi c np,

n s to ra bn trong ng cc dng mt in trng mnh v khi dng kh mang bi

i qua, nhng phn t kh trong dng kh s b ion ha ri truyn in tch m cho htbi di cc tc ng va p qun tnh v/ hoc khuch tn ion. Nh th cc ht bi b

ht v pha cc dng, ng li trn b mt trong ca ng hnh tr, mt in tch v ri

xung phu cha bi. Kh sch theo ng ng dn kh thot ra ngoi.

- c im:

+ Thit b s dng dng in mt chiu c U = 30 - 70 kV

+ Yu cu bi vo thit b phi kh.

+ Hiu sut lc bi cao: = 95-99%.

+ Lc c tt c cc loi bi t kch thc ln n kch thc nh.

+ Gi thnh t

- Phm vi p dng:

Thit b ny ch c s dng nhng ni cn thu hi nhng loi bi qu c

gi tr hoc nhng ni yu cu cht lng mi trng cao.

Ngoi loi thit b lc bi bng in kiu ng, ngi ta cn c th to cc dng ht

bi bng cc tm bn t song song hai bn cc dy cc m v lc ta c thit b lc

bng in kiu tm bn nh hnh 3.8

Hnh 3.8. Thit b lc bi bng in kiu tm bn


36/154

- 36 -

3.2.2. X l bi bng phng php t

* Nguyn tc:

Nguyn l ca qu trnh l da vo s tip xc gia dng kh mang bi vi cht

lng, bi trong dng kh b cht lng gi li v thi ra ngoi di dng cn bn.Phng php lc bi bng thit b lc kiu t c th xem l rt n gin nhng hiu

qu li rt cao.

* c im:

- u im:

+ Thit b lc bi kiu t d ch to, gi thnh thp nhng hiu qu lc bi cao.

+ C th lc c bi kch thc thc di 0,1m.

+ C th lm vic vi kh c nhit v m cao m mt s cc thit b lc

bi khc khng th p ng c nh lc bng ti vi, lc bng in.

+ Thit b lc bi kiu t khng nhng lc c bi m cn lc c c kh

c hi bng qu trnh hp th, bn cnh cn s dng nh thit b lm ngui v lm

m kh m trong nhiu trng hp trc thit b lc bi bng in phi cn n n.

- Nhc im:

+ Bi thi ra di dng bn cn gy kh khn cho vic thu gom bi ng thi

lm phc tp cho h thng thot nc v x l nc thi.

+ Dng kh thot ra khi thit b mang theo lng hi nc c th gy n mn

cc thit b pha sau thit b lc nh ng ng, ng khi,

+ Trong trng hp khi thi cha nhiu cht d n mn nh: SO2, CO2,

cng c kh nng lm cho cc ng ng v thit b b n mn v vy cn phi s dng

nhng vt liu chng g nh inox, cht do hoc m cc thit b .

Thit b lc bi kiu t thng c th chia thnh cc loi sau y ty thucvo nguyn l hot ng ca chng:

- Bung phun, thp ra kh rng.

- Thit b kh bi c lp m bng vt liu rng ti nc.

- Thit b lc bi (ra kh) c a cha nc si bt.

- Thit b lc bi (ra kh) vi lp ht hnh cu di ng.

- Xyclon t.


37/154

- 37 -

a. Bung phun -Thp ra kh rng

- Cu to: Hnh 3.9

Hnh 3.9.Bung phun hoc thp

ra kh rng

1. V thit b b.

2. Vi phun nc.

3. Tm chn nc.

4. B phn hng dng v phn

phi kh.

- Nguyn tc hot ng

Dng kh mang bi i vo thit b t di qua sn phn phi ln trn, dng

nc c phun di dng ht nh t trn xung. Khi hai mi cht tip xc nhau, bi

trong dng kh b cun theo nc i xung di, cn kh sau khi tch bi, qua b phn

chn nc tch c hi nc thot ra ngoi u thit b.

- c im:

+ Yu cu vn tc dng kh vo thit b trong khong (0,6 1,2) m/s.

+ Hiu sut x l ph thuc vo cng phun nc v vn tc dng khng

kh chuyn ng trong thit b.

+ Cu to thit b n gin, gn, d ch to.

+ Vn hnh d.+ Hiu sut x l kh cao: = 80-90%.

- Phm vi p dng:

Thit b ny c s dng ph bin lc bi th trong kh thi ng thi

lm ngui kh.

b. Thit b kh bi c lp m bng vt liu rng ti nc

- Cu to:


38/154

- 38 -

Gm mt thng tit din trn hoc

ch nht bn trong c cha mt lp m

bng vt liu rng v c ti nc.

Hnh 3.10. Thp ra kh Scrub

1. Tm c l;

2. Lp vt liu rng;

3. Dn ng phun nc

- Nguyn tc hot ng:

Kh i t di ln xuyn qua lp vt liu rng, khi tip xc vi b mt t ca

lp vt liu rng bi s bm li cn kh sch thot ra ngoi. Mt phn bi s b

nc cun tri xung thng cha v c x ra di dng bn cn. nh k ngi ta

thau ra lp vt liu rng.

- c im:

+ Vt liu rng thng dng cc loi khu c hnh dng khc nhau lm bng s,

thy tinh, nha

+ Cu to thit b n gin.

+ Hiu sut x l cao hn so vi thp ra kh rng, = 90% i vi cc ht

c > 2.

+ Tr lc thit b ln.

+ Phi nh k thau ra lp vt liu rng.

- Phm vi p dng:+ p dng lm bc lc bi th nht trong cc h thng ht bi my p nh

va phn loi, my d khun trong cc phn xng c.

+ Lm bc lc ln th hai trong cc h thng lc bi c nng bi ban u

ln.

* Ngoi loi thp phun nc kiu ng chuyn ng ngc chiu ca kh v nc nh

trn, ngi ta cn ch to loi thit b phun c lp m rng kiu nm ngang (hnh


39/154

- 39 -

3.11). Cu to ca loi thit b ny cho php lm vic vi vn tc kh ln hn so vi

thit b thng ng (c th t 10 m/s) nh kch thc ca loi thit b ny s gn

nh hn.

Hnh 3.11. Thit b phun nc c lp m rng kiu nm ngang1. Vi phun; 2. V v khung; 3. H thng ti nc; 4. Phn khng ti nc

ca lp m thay cho tm chn nc; 5. B cha cn bn; 6. Lp vt liu rng.

c. Thit b lc bi (ra kh) c a cha nc si bt

- Cu to:

Hnh 3.12. Thit b lc bi c a cha nc si bt

a) Loi gii nc dp kh: 1. V thit b b; 2. Vi phun nc; 3. a c l.

b) Loi chy trn: 1. V thit b b; 2. a c l; 3. Hp cha nc cp vo; 4. Tm

chn chy trn; 5. Hp x nc trn.


40/154

- 40 -

- Nguyn tc hot ng:

Nguyn tc lm vic ca thit b lc bi c a cha nc si bt l cp nc

vo a va to mt lp nc c chiu cao thch hp; dng kh i t di ln trn

qua a c l, lm cho lp nc si bt. Bi trong kh tip xc vi b mt ca nhngbong bng nc v b gi li ri theo nc chy xung thng cha.

- c im:

+ Thit b lc bi c a cha nc si bt c kh nng lc c bi c kch

thc 5 vi hiu qu lc tng i cao.

+ a c l dng trong thit b c th l l trn ng knh do = 4 - 8 mm hoc

rnh song song b rng b = 4 5 mm, b dy ca a c l cn ly trong khong 4 -6

mm.

+ Trong thit b si bt kiu chy trn, ngi ta thng dung a c l trn

ng knh l 3 8 mm. Vn tc kh qua tit din sng (din tch l) ca a 5 -15 m/s

tng ng vi vn tc kh trn ton tit din ngang ca thit b l 1 -3 m/s.

- Phm vi p dng:

Thit b ny thng c s dng x l bi trong cng nghip.

d. Thit b lc bi (ra kh) vi lp ht hnh cu di ng

- Cu to: Hnh 3.13

Vt liu ch to ht hnh cu l nha, cao su hoc thy tinh. Ht rng hoc

c, khi lng ring ca ht cu khng c vt qu khi lng ring ca nc

m bo cho cc ht hnh cu chuyn ng mt cch t do trong hn hp kh nc bn

trong thit b.

- Nguyn tc hot ng:

Kh mang bi c a vo thit b t di ln. Dng kh a vo ny lm chocc ht hnh cu chuyn ng hn lon trong trng thi l lng, bi trong kh va p

vo cc ht hnh cu tch khi dng kh. Nc c phun t trn xung cun theo cc

ht bi to thnh cn bn c dn ra ngoi x l.

- c im:

+ Hiu sut lc bi vi lp ht hnh cu di ng c hiu sut x l bi kh cao.


41/154

- 41 -

+ Vn tc dng kh vo cho php trong khong (5-6) m/s v t l nc kh l

(0,5-0,7) l/m3.

+ ng knh thch hp ca cc ht hnh cu l d = (20-40) mm.

+ Trng lng n v ca cc ht hnh cu: = (200-300) kg/m3

.+ Sc cn ca thit b kh ln: (900-1400) Pa.

Hnh 3.13. Thit b lc bi vi lp

ht hnh cu di ng1. Tm chn c l hoc li.

2. Ht cu.

3. Tm chn c l hoc li.

4. Vi phun nc.

5. Tm chn nc.

.

- Phm vi p dng:Thit b ny thng c p dng x l bi trong cc ngnh cng nghip.

e. Thit b lc bi kiu t di tc dng va p qun tnh

- Cu to:

Dng in hnh ca loi thit b lc bi theo nguyn l va p qun tnh t l

loi Rotoclon N.


42/154

- 42 -

- Nguyn tc hot ng:

Khi dng kh c ht vo thit b, kh s i vo rnh gia cc cnh hng

dng v ko theo nc to thnh mt mng nc tung te ln vi git mn 300-

400. S lun lch ca hn hp khng kh nc qua cc b mt c cu to thay

i s lm cho cc ht bi va p v ri xung. Kh sch gi ht bi c dn ra

ngoi.

- c im:

+ Thit b ny khng cn phng tin vn chuyn nc phun vo thit b,

khng cn vi phun. Ch cn mt lng nc cha sn trong thit b v c sung thm

bng h thng cp nc sinh hot thng thng, khng cn bm p lc cao.

+ ng knh ca ht nc t 300-400.

+ Vn tc kh vo thit b l 15 m/s. Vn tc dng kh ra khi qut kh ln.

+ p lc ca thit b l 2700 3000 N/m2.

+ Lng nc tiu hao cho qu trnh ny thng khng qu ln, thng 0,7 l/m3

+ Nng lng tiu th cho loi thit b ny nm trong khong 1,0 1,3 kWh

cho 1000 m3/h lu lng kh cn x l.

- Phm vi p dng:

+ Thit b lm vic c vi nng bi ban u rt cao.

+ Rotoclon N thng c s dng rng ri trong cng nghip luyn kim

lc bi thng thng v bi c tnh kt dnh cng nh cc loi bi d gy chy n

Hnh 3.14.Rotoclon - N

1. Ming vo ca kh

2. Cnh hng dng

3. Tm chn nc

4. Ming dn kh sch thot ra.

5. Qut ht


43/154

- 43 -

f. Xyclon t

- Cu to:

Hnh 3.15.Xyclon LIOT c mng nc- Nguyn tc hot ng:

Nc c phun ra theo chiu thun vi chiu chuyn ng xon c ca dng

kh bn trong xyclon v phi to ra c mng nc mng chy t trn xung di v

lng khp mt trong ca thn xyclon. Kh i vo xyclon t di ln trn bng ng dn

vo ni theo phng tip tuyn vi v tr ca xyclon to cho dng kh c chuyn

ng xon c. Bi tch ra chm vo thnh ng b nc cun i nn khng c kh nng

bn ngc tr li vo dng kh. ng thot kh ra cng c ni theo phng tip tuyn

vi v tr thun chiu quay xon c ca dng kh bn trong xyclon.

- c im:

+ Vn tc dng kh vo v = (18-22) m/s.

+ Hiu sut x l cao, >90%, c th ln n 99% .

+ Thit b gn nh.


44/154

- 44 -

+ Lc c c bi v c ln bi hu c (nhng khng lc c cc loi bi k

nc).

+ Lp t v vn hnh phc tp.

+ Cn phi c thm cng trnh ph tr l b cha nc.- Phm vi p dng:

C th p dng lc bi kt hp vi x l cc cht c hi trong kh thi,

ng thi c th s dng gim nhit khi thi.


45/154

- 45 -

CHNG 4. CC PHNG PHP X L HI V KH C

4.1. KHI QUT CHUNG

Khc vibi, kh v hi tn ti di dng ccphn t ringbit ln vo

khngkhtheoccchuynngchaose.iukinbnh thnghic thngng tc,cnkh thchngng t

c khitocpsuthocnhitphhp(psutcao,nhitthp).

X lhihockh thichic th tinhnhbngccphngphp tiu

hy, ngng t, hpphhoc hp th. Ty thuc vo iu kin pht sinh, nng

cht nhim, iu kin a hnh, trang thit b hin c la chn p dng cc

phng php x l khc nhau.

4.2. X L KH V HI BNG PHNG PHP HP TH

4.2.1. Khi nim

Hp th kh bng cht lng l qu trnh ha tan cht kh trong cht lng khi

chng tip xc vi nhau.

Qu trnh ha tan cht kh trong cht lng gm ba bc chnh:

- Khuch tn cc phn t cht nhim th kh trong khi kh thi n b mt

ca cht lng hp th.- Thm nhp v ha tan cht kh vo b mt ca cht hp th.

- Khuch tn cht kh ha tan trn b mt ngn cch vo su trong lng khi

cht lng hp th.

Tu thucvobnchtcas tng tc gia cht cn c hp th v cht

hp thmngitachiathnhshp thvtlhayshpthhahc:

- Hp th vt l: l qu trnh da trn s tng tc vt l thun ty;

ngha l ch bao gm s khuch tn, ha tan cc cht cn hp th vo trong lng

cht lng v s phn b ca chng gia cc phn t cht lng. V d nh s phn b

ca kh ho tan gia cc phn t cht lng: NH3/aceton, CO/benzen,

trimetylamin/du ho, s ho tan ca kh SO3/H2SO4.

- Hp th ha hc: l mt qu trnh lun i km vi mt hay nhiu phn ng

ha hc. Mt qu trnh hp th ho hc bao gi cng bao gm 2 giai on:

giai on khuch tn v giai on xy ra cc phn ng ha hc.


46/154

- 46 -

Phng php hp th cht nhim bng cht lng c s dng kh ph bin

trong x l kh thi Vit Nam, hay c p dng x l cc loi kh nh SO 2, CO2,

H2S, NOx,Cht lng hp th c th l nc, axit, baz

4.2.2. Cc cht hp thTrong k thut x l kh thi bng phng php hp th, nc l loi cht hp

th sn c, gi r v thun li nht. Tuy nhin, nc ch hp th c mt s t loi kh

c hi, hn na mc hp th vt l ca nc cng b hn ch. Trong nhiu trng

hp ngi ta phi p dng phng php hp th ha hc bng cc loi dung dch ha

cht khc nhau ty theo cht c hi cn kh, c th nh sau:

Bng 4.1.Mt s cht hp th x l cc kh nhim thng gp

Kh nhim cn kh Cht hp th

Oxit nit: N2O3, NO2,

N2O5

Nc v cc cht huyn ph: dung dch NaOH,

Na2CO3, NaHCO3, KOH, K2CO3, KHCO3, Ca(OH)2,

CaCO3, MgCO3, Mg(OH)2 , Ba(OH)2, BaCO3,

NH4HCO3

Nit Oxit NODung dch FeCl2, FeSO4, Na2SO3, Na2S2O3, NaHCO3,

NaHSO3

Sunfua ixit SO2Nc, dung dch NaOH, Ca(OH)2, CaCO3, K2CO3,

Na2CO3 (15-20)%, KOH,

ihyro sunfua H2S

Dung dch Na2CO3 + Na3AsO4

Dung dch AsO3 (8-10)g/l + NaCl (1,2-1,5)g/l

(NH4)3AsO3 (3,5-6) g/l.

Cacbon oxit CO Nit lng, dung dch [Cu(NH3)]n, COCH

Cacbon ioxit CO2 Dung dch Na2CO3, NaOH, KOH, K2CO3, Ca(OH)2

Cc ha cht cha Flo:

HF, SiF4Nc, dung dch NaOH, Ca(OH)2, Na2CO3

Clo Cl2 Dung dch: NaOH, KOH, Ca(OH)2

Hi, sng HClNc, dung dch Na2CO3, NaOH, KOH, K2CO3,

Ca(OH)2


47/154

- 47 -

4.2.3. Thit b hp th

Thit b hp th c chc nng to ra b mt tip xc cng ln cng tt gia hai

pha kh v lng. C rt nhiu dng kiu khc nhau ca thit b hp th, nhng c th

phn chia thnh bn loi chnh sau y:- Bung phun, thp phun: trong cht lng c phun thnh git nh trong

th tch rng ca thit b v cho dng kh i qua.

- Thit b sc kh: kh c phn tn di dng cc bong bng i qua lp cht

lng. Qu trnh phn tn kh c th thc hin bng cch cho kh i qua tm xp, tm

c l hoc bng cnh khuy c hc.

- Thit b hp th kiu si bt: kh i qua tm c l bn trn c cha lp nc

mng.

- Thit b hp th c lp m bng vt liu rng: Cht lng c ti trn lp

m rng v chy xung di to thnh b mt t ca lp m dng kh tip xc

i qua.

a. Thp hp th phun kiu thng rng

- Cu to:

Thit b hp th kiu thng

rng c dng hnh tr, c vi phun

sng thng c t pha trn

phun xung. Trong trng hp thp

hp th c chiu cao ln, ngi ta

thng t cc vi phun chia ra cc

tng khc nhau.

Hnh 4.1. Thp phun kiu thng rng


48/154

- 48 -

- Nguyn tc lm vic:

Trong thpphun, cht lng cphun thnhbi m (sng) tpha trn

xung, kh thngi t di lnnhm lm tng din tch tip xc v nng

thc t ca cht cn hp th trongpha kh gim dn theo chiu t dii ln vnngchtbhpthtrongphalngctngdntheochiuttrn ixung.

- c im:

+ Yu cu tcdngkhkhngcquln(phinhhn1m/s)trnh

hin tngchtlngbcuntheokhrangoi.

+ Thitb hp th thng rng c u i m l n gin, chi ph u t thp,

lc cn thy ng nh v c th s dng i vi kh thi c nhimbn cao;

cht lng dng hp th c th quay vng cho ti khi hp th no mi thi cho

nntitkimccht hpth.

+ Tuy nhin, nhc im ca thitb thng rng l kh thngphnb

khngutrongton bthpdndnlmgimhiusutxl.

b. Thp m

- Cu to:

c dngphbin nht. Trong thp, ngi ta thng nhi cc vt liu

mnh c,snhs, lsokim loi.vnthancc... lm tngdin tch tipxc

hai pha.

- Nguyn tc lm vic:

Cht lng c ti trn b mt lp vt liu rng v chy t trn xung di

to ra b mt t ca lp vt liu m. Kh c dn t di ln tip xc vi cc b

mt t , cc cht nhim b hp th li, kh sch c dn ra ngoi.

- c im:+ Thit b ny vn hnh n gin nhng hiu qu x l cao.

+ Vt liu m d b tt nghn do tch t cn, do lm tng tr lc qu trnh

hp th.

c. Thp hp th si bt (ging thp si bt trong x l bi)

Thngcsdngtrongtrnghptilngcao,psutkhphilnv

qu trnhhpthcstonhit,cnclmlnh.


49/154

- 49 -

Hp th kiu sibt c nhc im ln nht l lun c lpbt chim th

tch kh ln trong thitb. Vic chuyn ng ca cht lng gpphi tr lc ln.

Ccnh thitkcnhiucng trnhlmgimbtnhngnhcim trnc

thsdng kiuhpthnytrongcngnghipvnchschuynkhirtcao.Chiu cao lpcht lng tng s lm tng kh nng hp th song ng thi

cng tng tr lc ca thitb. V vy, thng thng ngi ta khng tng lp cht

lngqu 50mm.

4.2.4. V d v x l kh SO2 bng phng php hp th (cht hp th l nc)

Hp th kh SO2 bng nc l phng php n gin c p dng sm nht

loi b kh SO2 trong kh thi, nht l khi t cc loi l cng nghip.

S h thng x l kh SO2 bng nc bao gm 2 giai on:

- Hp th kh SO2 bng cch phun nc vo dng kh thi hoc cho kh thi i

qua lp vt liu m (vt liu rng) c ti nc scrub.

- Gii hp kh SO2 ra khi cht hp th thu hi SO2 (nu cn) v nc sch.

Hnh 4.2. S h thng x l kh SO2 bng nc

1. Thp hp th; 2. Thp gii thot kh SO2; 3. Thit b ngng t;

4,5. Thit b trao i nhit; 6. Bm.


50/154

- 50 -

Mc ha tan ca kh SO2 trong nc gim khi nhit nc tng cao, do

nhit nc cp vo h thng hp th SO2 phi thp. Cn gii thot kh SO2

khi nc th nhit ca nc phi cao. C th l nhit 100oC th SO2 s thot

ra khi dung dch hp th hon ton v trong khi thot ra c ln c hi nc. Bngphng php ngng t ngi ta c th thu c kh SO2.

- u nhc im:

+ u im:

Cng ngh n gin.

Nc l dung mi d kim v r tin.

+ Nhc im:

Hiu sut thp, nu kh thi sch bi th hiu sut ch t = 50%

gii hp th cn phi un nng mt lng nc rt ln tc l cn

phi c mt ngun cp nhit cng sut ln.

Ngoi ra, s dng nc cho qu trnh hp th phi lm ngui nc

xung 10oC tc l phi cn n ngun cp lnh, gy tn km chi ph.

- Phm vi p dng:

+ Phng php ny p dng ti cc khu vc c sn ngun cp nhit (hi nc),

c sn ngun lnh.

+ p dng nhng ni c sn lng nc thin nhin v ni cho php thi

lng H2SO4 ra mi trng (sng ngi).

4.3. X L KH V HI BNG PHNG PHP HP PH

4.3.1. Khi nim

Hp ph l qu trnh phn ly kh da trn i lc ca mt s cht rn i vi mt

s loi kh c mt trong hn hp kh ni chung v trong kh thi ni ring, cc phn tcht kh nhim trong kh thi b gi li trn b mt ca vt liu rn.

Vt liu rn s dng trong qu trnh ny c gi l cht hp ph, cn cht kh

b gi li trong cht hp ph c gi l cht b hp ph.

Phng php hp ph c s dng x l mi hi, thu hi mt s cht

kh c gi tr hoc kh hi dung mi v mt s cht kh khc.

4.3.2. c im ca qu trnh hp ph


51/154

- 51 -

Qu trnh hp ph c p dng rt ph hp cho nhng trng hp sau:

+ Cht kh nhim khng chy c hoc kh t chy.

+ Cht kh cn kh l c gi tr v cn thu hi.

+ Cht kh nhim c nng thp trong kh thi m cc qu trnh kh khkhc khng th p dng c.

Qu trnh hp ph c chia thnh hp ph vt l v hp ph ha hc:

+ Hp ph vt l:

Cc phn t kh b ht vo b mt ca cht hp ph nh c lc lin kt

gia cc phn t (lc Vander Waals).

Qu trnh hp ph vt l c ta nhit, Q = (2 20) kJ/g.mol. Lng nhit

ny ph thuc vo cng ca lc lin kt phn t.

Qu trnh hp ph vt l l qu trnh thun nghch. y l qu trnh c

ngha quan trng nh ta c th thu hi cc cht kh b hp ph c gi

tr hoc c th hon nguyn cht hp ph bo ha ti s dng.

Lng kh b hp ph vt l gim nhanh khi tng nhit tng. Lng

kh b hp ph t l thun theo din tch b mt ca vt liu hp ph.

Hp ph vt l c tc hp ph din ra rt nhanh.

+ Hp ph ha hc:

Hp ph ha hc l kt qu ca c phn ng ha hc gia cht b hp

ph v vt liu hp ph.

y l qu trnh m lng nhit ta ra rt ln, Q = (20 400) kJ/g.mol.

Qu trnh hp ph ha hc l qu trnh khng thun nghch

4.3.3. Vt liu hp ph

Vt liu hp ph thng dng ht, kch thc c ht t 6 10 mm xung nc 200, c rng ln c hnh thnh do nhng mao qun li ti nm bn trong

khi vt liu.

Vt liu hp ph cn p ng cc yu cu sau:

+ C kh nng hp ph cao.

+ Phm vi p dng rng, kh c nhiu loi kh khc nhau.

+ C bn c hc cn thit.


52/154

- 52 -

+ C kh nng hon nguyn d dng.

+ Gi thnh r.

Vt liu hp ph c th c chia thnh ba nhm chnh:

+ Vt liu khng c cc.+ Vt liu c cc.

+ Vt liu m trn b mt ca chng xy ra qu trnh hp ph ha hc v qu

trnh lm thay i cu trc ca phn t kh.

Tuy nhin, vt liu c s dng ph bin nht l loi vt liu khng c cc,

i vi loi vt liu ny rng cng ln th kh nng hp ph cng cao.

Kch thc l rng (ng knh mao qun) ng vai tr quan trng lm cho vt

liu hp ph c kh nng hp ph chn lc.

Trong cng ngh x l mi trng, lm sch cc hi v kh thi

ngi ta thng s dng cc cht hp ph xp nh than hot tnh, silicagel, zeolit

4.3.4. Thit b hp ph

Trong thit b hp ph, vt liu hp ph c thnh lp m c b dy nht

nh v cho dng khi cn x l i qua.

Hnh 4.3. S thp hp ph s dng than hot tnh


53/154

- 53 -

Yu cu ra khi thit k hoc la chn thit b hp ph l:

+ Phi m bo thi gian chu k hp ph thch hp.

+ C x l s b i vi kh thi loi b mt s cht m m vt liu hp phkhng hp thu c.

+ X l lm gim bt nng ban u ca cht cn kh trong kh thi bo

v lp vt liu hp ph khi b qu ti.

+ Phn phi dng kh i qua lp vt liu hp ph mt cch u n.

+ m bo kh nng thay th mi hay hon nguyn vt liu hp ph sau khi t

trng thi hp ph mt cch d dng.

4.3.5. Hon nguyn vt liu hp ph

Khi xut hin im ngng, l im m nng cht nhim u ra ca

thit b x l khng gim m c xu hng tr li bng ban u hoc bt u tng

hn so vi nng ban u, cn phi ngng chu k hp ph v chuyn sang chu k

hon nguyn gii thot cht nhim b hp ph trn b mt vt liu.

C th p dng cc phng php sau y hon nguyn vt liu hp ph:

+ Hon nguyn bng nhit: Vt liu hp ph c sy nng ln kh nng

hp ph ca n gim xung n mc thp v lc cht kh b hp th s thot ra

ngoi. Sau khi hon nguyn xong tng kh nng hp ph phi lm ngui vt liu

hp ph trc khi a vo s dng li. Ph bin nht ca phng php nhit l dng

khng kh nng hoc hi nc.

+ Hon nguyn bng p sut: nhit khng i, nu p sut gim th kh

nng hp ph gim v do cht b hp th s thot khi b mt vt liu.

+ Hon nguyn bng kh tr: Dng kh tr khng cha cht kh b hp ththi qua vt liu hp ph y cht kh b hp ph ra khi vt liu hp ph.

Trong cc phng php trn, phng php nhit bng hi nc c p dng

rng ri nht vi l do n gin, t tn km v hiu qu cao.

4.3.6. V d v x l kh H2S bng phng php hp ph (cht hp ph l oxyt st)

X l H2S bng cht hp ph oxit st Fe2O3 l phng php x l c in nht

da trn cc phn ng sau:


54/154

- 54 -

Fe2O3 + 3H2S Fe2S3 + 3H2O (1)

2Fe2S3 + 3O2 2Fe2O3 + 6S (2)

Hnh 4.4. S h thng hp ph H2S bng oxit st

1. Bnh hp ph, 2. Eject

Sau khi bo ha H2S, oxit st c hon nguyn bng khng kh (cp oxy)

thu lu hunh.

Tc phn ng hp ph H2S ca oxit st ph thuc vo mc tip xc gia

kh v b mt vt liu hp ph. Do nng cao tc phn ng, rng (xp) ca

vt liu phi ln. Thng rng ca oxit st khng nh hn 50%.

iu kin cho qu trnh hp ph H2S bng oxit st ph thuc vo cc yu t sau:

+ Nhit ca mi trng: nhit ca mi trng tt nht nm trong khong

(28 30) oC.

+ m ca vt liu hp ph: khong 30%.

hon nguyn vt liu hp ph c th p dng cc phng php khc nhau:

+ Oxy ha vt liu hp ph bng oxy trong khng kh.

+ Thi hn hp kh c cha 2% 3% oxy qua lp vt liu hp ph. Nhit

hon nguyn 600 oC - 800 oC.


55/154

- 55 -

+ Hon nguyn lin tc khi vt liu hp ph bng cch b sung vo dng kh

cn x l mt th tch khng kh c tnh ton. Nh vy qu trnh hon nguyn s xy

ra song song vi qu trnh hp ph.

4.4. X L KH V HI BNG PHNG PHP THIU T4.4.1. Khi nim

X l kh thi bng qu trnh thiu t hoc cn gi l t chy sau c p

dng kh ph bin trong cc trng hp sau:

- Dng trong trng hp lu lng kh thi ln m nng cht nhim li rt

b m cc phng php khc thc hin khng hiu qu.

- Cc cht nhim c mi nh H2S, NH3, cc hi dung mi.

- Cc loi sol kh hu c c khi nhn thy c, v d nh khi t l rang cph, l sn xut tht hun khi, l nung men s,

- Mt s hi, kh hu c nu thi trc tip ra mi trng s gy hin tng khi

quang ha.

- Kh thi t cng ngh khai thc v lc du.

4.4.2. Cc u, nhc im ca phng php

Nhng u, nhc im ca phng php x l nhim bng thiu t c th

nu ra nh sau:

- u im:

+ Phn hy c hon ton cc cht nhim chy c khi thit b thiu t

c thit k v vn hnh theo ng quy cch.

+ Kh nng thch ng ca thit b i vi s thay i va phi ca lu lng

kh thi cng nh nng cht nhim trong kh thi.

+ Hiu qu x l cao i vi cc cht nhim c bit m cc phng php

khc x l khng hiu qu hoc hiu qu thp.+ C kh nng thu hi, tn dng nhit thi trong qu trnh thiu t.

+ Cng ngh kh n gin, an ton trong vn hnh.

- Nhc im:

+ Chi ph u t thit b v vn hnh tng i ln.

+ C kh nng lm phc tp hn vn nhim khng kh.

+ Phi cn c h thng thu gom v x l tro bi trong qu trnh t.


56/154

- 56 -

+ Trong qu trnh thiu t c cp thm nhin liu hoc c xc tc -> gy cn

tr cho qu trnh vn hnh thit b.

4.4.3. Cc qu trnh thiu tV mt bin php thc hin, qu trnh thiu t cht nhim c th c phn

chia thnh ba dng khc nhau:

- Thiu t bng ngn la trc tip trong khng kh.

- Thiu t c bung t.

- Thiu t c xc tc.

a. Thiu t bng ngn la trc tip

Thiu t bng ngn la trc tip l bin php lm cho kh nhim chy trc

tip trong khng kh m khng cn cp nhin liu b sung, trng hp chung, ch cn

nhin liu mi la v iu chnh khi cn thit.

Cn c vo gii hn chy ca cht ngi ta c th chia kh thi c cha cc cht

nhim chy c thnh ba nhm sau:

- Nhm 1: Thnh phn nhin liu trong kh thi thp hn gii hn di ca qu

trnh chy khong 25%.

- Nhm 2: Thnh phn nhin liu trong kh

thi nm trong phm vi t gii hn di n gii

hn trn ca qu trnh chy.

- Nhm 3: Thnh phn nhin liu trong kh

thi cao hn gii hn trn ca qu trnh chy.

Hnh 4.5.u t ca h thng thiu tbng ngn la trc tip

1. ng dn kh thi

2. Vng khng ch vn tc kh thi

3. ng gp phn phi hi nc

4. Cc im phun hi

5. B phn mi la.


57/154

- 57 -

b. Thiu t c bung t

Thiu t c bung t c p dng rng ri i vi cc loi kh thi c cha

cht nhim dng kh, hi hoc sol kh chy c vi nng tng i thp.

Cc b phn chnh v quan trng ca h thng thiu t ny l bung t, ccvi t, b phn iu chnh qu trnh chy v dng c ch th nhit .

Bung t thng c dng hnh tr v c xy dng bng v thp c p gch

chu la. Nhit trong bung t khong 900 oC - 1500 oC. Vn tc kh trong bung

t dao ng trong khong 5 8 m/s v thi gian lu li ca dng kh trong bung t

khong 0,2s 0,5s.

Hnh 4.6. S cu to ca bung t

1. Kh thi i vo thit b thiu t; 2. B mt trao i nhit sy nng kh thi;3. Nhin liu; 4. Vi t; 5. Kh sch ra.

Trong qu trnh t nu cn thit phi cho thm nhin liu ph tr vo bung

t.

Khi nng cht chy trong kh thi qu thp, nhit lng chy ca n khng

duy tr s chy, ngi ta thng dng bin php hm nng kh thi trc khi a

vo bung t.

c. Thiu t c xc tcThiu t c xc tc l mt bc pht trin tip theo ca cng ngh x l kh

thi trong khng gian kn bung t.

Phng php ny c nhng u im sau:

- Lm gim nhit ca bung t.

- Phn ng chy trn b mt vt liu xc tc din ra rt nhanh v cng rt

mnh.


58/154

- 58 -

- Nhit chy trn b mt cht xc tc thp hn, vo khong 200 oC - 450oC.

Tuy nhin, phng php thiu t c cht xc tc cng c nhng nhc im sau:

- Vt liu xc tc thng l cc kim loi qu nn gi thnh rt t. Tuy nhin

lng xc tc i hi khng nhiu, thng ch cn t 0,03 m3

0,12 m3

cho 1m3

khthi cn oxy ha trong 1s.

- Mun t hiu qu cao ca qu trnh chy th yu cu trong kh thi vo phi

sch bi v tp cht. Do kh thi trc khi a vo x l bng oxy ha c xc tc

cn c lc bi n mt mc cho php.

Hnh 4.7. S cu to bung t c xc tc

1. Lp m bng vt liu xc tc; 2. B mt trao i nhit sy nng kh thi;3. Kh thi dn vo; 4. Kh sch thot ra ng khi; 5. Cp nhin liu; 6. Cp khng

kh; 7. Vi t; 8. ng dn kh thi vo bung t.

4.5. X L KH V HI BNG PHNG PHP NGNG T

Phng php ngng t thng p dng x l kh thi l cao, thng

dng khi nng cht nhim trong kh thi tng i thp v cc phng php

khc x l khng hiu qu.

Nguyn tc caphngphp l da trn s h thp nhit mi trng

xung mtgi trnhtnhthhunhccchtthhisngngtlivsau

c thu hi hoc x l tiu hy. iu kin lm lnhbnh thng, nu x l

bng ngng t thng khi thu hi c hi cc dung mi hu c, hi axt. Tt

nhinphngphp ny chphhpvinhng trnghpkh thicnnghi

tngicao(>>20g/m3). Trong trng hp nng nh, ngi ta thng dng


59/154

- 59 -

ccphngphphpphhay hpth.

Hnh 4.8. Thit b ngng t dng tip xc


60/154

- 60 -

PHN 2: CNG NGH X L NC THI

CHNG 5. MT S VN C BN LIN QUAN

N NC THI5.1. NGUN GC, LU LNG V THNH PHN NC THI

5.1.1. Phn loi nc thi

Ngi ta nh ngha nc thi l cht lng c thi ra sau qu trnh s dng

ca con ngi v b thay i tnh cht ban u ca chng. Thng thng nc thi

c phn loi theo ngun gc pht sinh ra chng. cng l c s cho vic la chn

cc bin php hoc cng ngh x l. Theo cch phn loi ny, c cc loi nc thi

sau y:

- Nc thi sinh hot: l nc thi t cc khu dn c, khu vc hot ng thng

mi, cng s, trng hc v cc c s tng t khc.

- Nc thi cng nghip: l nc thi t cc nh my ang hot ng, c c

nc thi sinh hot nhng trong nc thi sn xut l ch yu.

- Nc thm qua/ nc chy trn: nc thm qua l tt c cc loi nc chy

vo h thng cng rnh do s r r, b v ng ng hoc thm qua tng chn. Nc

chy trn l lng nc ma chy vo h thng cng rnh t h thng tiu nc ma,

mi nh, h ph, ...

- Nc thi t nhin: nc trn mt do ma ti ch hoc do tuyt tan.

Nc thi th l thut ng chung ch cc loi nc c thi b ra t cc

khu th, n l hn hp ca cc loi nc thi k trn.

Ngoi ra, theo quan im qun l mi trng, cc ngun nhim nc cn

c phn thnh hai loi: ngun xc nh (c th kim sot c) v ngun khng xcnh (kh kim sot, qun l)

- Cc ngun xc nh bao gm nc thi sinh hot v cng nghip, cc ca

cng x nc ma v tt c cc ngun thi vo ngun tip nhn c t chc qua h

thng cng v knh thi.

- Cc ngun khng xc nh bao gm nc chy tri trn b mt t, nc ma

v cc ngun nc phn tn khc.


61/154

- 61 -

5.1.2. Nc thi sinh hot

a. Ngun gc

Nc thi sinh hot l nc c thi b sau khi s dng cho cc mc ch sinh

hot ca cng ng: tm, git gi, ty ra, v sinh c nhn,Chng c thi ra tcc cn h, c quan, trng hc, ch, v cc cng trnh cng cng khc.

Nc thi sinh hot c phn chia thnh hai nhm:

- Nc en: l nc thi t cc nh v sinh, cha phn, nc tiu, vi khun

gy bnh.

- Nc xm: nc thi tm git, nu n,, cha cc thnh phn v c cao

(ch yu l cht rn l lng), cht ty ra, du m.

b. Lu lng

Lng nc thi sinh hot ca khu dn c c xc nh theo tiu chun cp

nc (TCVN 33-2006), thng thng tiu chun nc thi sinh hot ly bng (60-

80)% tiu chun cp nc. Cc trung tm th thng c tiu chun cp nc cao

hn so vi cc vng ngoi thnh v nng thn, do lng nc thi sinh hot tnh

trn mt u ngi cng c s khc bit gia thnh th v nng thn. Ngoi ra, lng

nc thi ca khu dn c cn ph thuc vo iu kin trang thit b v sinh nh , c

im kh hu thi tit v tp qun sinh hot ca ngi dn.

Lng nc thi sinh hot ti cc c s dch v, cng trnh cng cng ph

thuc vo loi cng trnh, chc nng, s ngi tham gia, phc v trong .

Bng 5.1. Tiu chun nc thi ca mt s loi c s dch v v cng trnh cng cng

Ngun nc thi n v tnh Lu lng

(lt/n v tnh.ngy)

Nh ga, sn bay Hnh khch 7,5 - 15Khch sn Khch 152 - 212

Nhn vin phc v 30 - 45

Nh n Ngi n 7,5 - 15

Siu th Ngi lm vic 26 - 30

Trng i hc Sinh vin 56 - 113


62/154

- 62 -

Bnh vin Ging bnh 473 - 908

Nhn vin phc v 19 - 56

B bi Ngi tm 19 - 45

Khu trin lm, gii tr Ngi tham quan 15 - 30Ngun: Metcalf & Eddy, Wastewater Engineering Treatment, Disposal, Reuse, 2004

Ch thi ca nc thi sinh hot c th lin tc (iu ha hoc khng iu

ha) hoc gin on (khng n nh). S dn ca thnh ph cng ng th ch thi

cng iu ha.

c. Thnh phn nc thi

Thnh phn nc thi sinh hot ph thuc vo tiu chun cp nc, c im

h thng thot nc, iu kin trang thit b v sinh,Nng cc cht nhim trong

nc thi sinh hot c nu trong bng 5.2

Bng 5.2. Thnh phn nc thi sinh hot khu dn c

Ch tiu Trong khong Trung bnh

Tng cht rn (TS), mg/l

- Cht rn ha tan (TDS), mg/l

- Cht rn l lng (TSS), mg/l

350 - 1200 720

250 - 850 500

100 - 350 220BOD5, mg/l 110 - 400 220

Tng Nit, mg/l

- Nit hu c, mg/l

- Nit Amoni, mg/l

- Nit Nitrit, mg/l

- Nit Nitrat, mg/l

20 - 85 40

8 - 35 15

12 - 50 25

0 - 0,1 0,05

0,1 - 0,4 0,2

Clorua, mg/l 30 - 100 50

kim, mgCaCO3/l 50 - 200 100

Tng cht bo, mg/l 50 - 150 100

Tng Pht pho, mg/l 4 - 15 8

Ngun: Metcalf & Eddy, Wastewater Engineering Treatment, Disposal, Reuse, 2004


63/154

- 63 -

Trong qu trnh sinh hot, con ngi x vo h thng thot nc mt lng

cht bn nht nh, phn ln l cc loi cn, cht hu c, cc cht dinh dng. c

trng ca nc thi sinh hot l hm lng cht hu c ln (t 50 n 65% tng lng

cht bn), cha nhiu vi sinh vt, trong c vi sinh vt gy bnh. Thnh phn chtbn trong nc thi sinh hot c biu din theo hnh 5.1.

Hnh 5.1. Thnh phn cc cht bn trong nc thi sinh hot

5.1.3. Nc thi cng nghip

a. Ngun gc

Nc thi cng nghip l dung dch thi ra t cc c s sn xut, ch bin, kinh

doanh, dch v cng nghip.

Trong cc x nghip cng nghip da vo ngun gc pht sinh ngi ta chia

nc thi cng nghip thnh ba loi sau:

- Nc thi sn xut: l nc dng ri trong qu trnh sn xut. Ngi ta phn

bit hai nhm nc thi sn xut l nc khng bn (qui c sch) v nc bn.

- Nc thi sinh hot: to ra t cc khu v sinh ca nh hnh chnh, nh snxut, t cc nh tm ca cc phn xng, hoc cc v tr c lp ring bit.

- Nc ma chy trn qua b mt nh my, x nghip.

y ch yu ta xt n nc thi sn xut. c im ni bt ca n l rt a

dng v thnh phn v khi lng.

b. Lu lng

Lu lng nc thi dao ng ty thuc vo quy m, tnh cht sn phm, quy

trnh cng ngh, vic tun hon nc ca tng c s sn xut.


64/154

- 64 -

Trong iu kin khng c s liu o c thc t, c th c tnh lu lng nc

thi theo lng nc cp vo (QNT Qcp) hoc theo phng php iu tra nhanh

ngun thi do WHO xut (1993). Nguyn tc ca phng php ny l da trn cc

s liu thng k a ra cc h s pht thi cho mi n v hot ng (nguyn liu tiuth, sn phm sn xut ra,) v cng sut ca nh my tnh ton lu lng v ti

lng nhim chnh ca tng loi hnh cng nghip.

Bng 5.3. Cc h s pht thi (theo WHO) i vi mt s ngnh cng nghip

Cng nghip n v tnh(U)

Th tchNT

(m3/U)

BOD5(kg/U)

TSS(kg/U)

TngN

(kg/U)

TngP

(kg/U)

Cc tc nhnkhc(kg/U)

313 Ru bia

3133 Nu nha vnu bia- Nh my mi m bia 5,4 10,5

bg-cong nghe moi truong c hong

Documents