Microsoft Word - GT Cong nghe moi truong.doc

TRNH TH THANH - TRN YM - NG KIM LOANGIO TRNHCNG NGH MI TRNG(ln ln th hai)NH XUT BN I HC QUC GIA H NINH XUT BN I HC QUC GIA H NI16 Hng Chui - Hai B Trng - H Niin thoi: (04) 9715012; (04) 7685236. Fax: (04) 9714899E-mail: nxb@vnu.edu.vnChu trch nhim xut bn:Gim c: PHNG QUC BOTng bin tp: PHM THNH HNGChu trch nhim ni dung.Hi ng nghim thu gio trnhTrng HKHTN - i hc Quc gia H NiNgi nhn xt: PGS. TS. TRN HNG CN TS. NGUYN TH LOANBin tp: LAN HNGBin tp ti bn: NGUYN TH HINTrnh by ba: NGC ANHGIO TRNH CNG NGH MI TRNGM s: 1K - 05040 - 02304In 1000 cun, kh 14,5 x 20,5 ti Nh in Khoa hc v Cng nghS xut bn : 183/113/XB - QLXB, ngy 10/2/2004. S trch ngang:129KH/XB In xong v np lu chiu qu III nm 2004.LI NI UMn hc "Cng ngh mi trng" c a vo chng trnh ging dy cho sinh vin ngnh Khoa hc Mi trng t khi thnh lp Khoa Mi trng (nm 1995). Cun sch tch ly kinh nghim ca gn chc nm th nghim trn cc bi ging, kt hp vi vic hc hi v tham kho ti liu ging dy mn hc ny ca Vin K thut Chu (AIT) - Thi Lan, cng nh cc ti liu khoa hc v cng ngh x l cht thi ca mt s nc trn th gii v trong khu vc. Trong cun sch ny, nhm tc gi mong mun truyn t nhng kin thc c bn, k nng tin hnh nghin cu x l cht thi pht sinh trong sn xut cng, nng nghip, giao thng vn ti, sinh hot...B cc ca cun sch gm 3 phn: x l cc cht gy nhim khng kh, x l nc v nc thi, x l cht thi rn.Phn "Cng ngh x l kh thi" do ThS. ng Km Loan bin son bao gm 4 chng u. Trong phn ny tc gi cp n nguyn nhn v cc ngun gy nhim khng kh, dng ca cc cht thi vo bu kh quyn, cc bin php ci thin bu khng kh ni sinh sng v lm vic. c bit tc gi thng k ton b cc phng php c p dng trong thc t x l bi v kh thi c hi, m in hnh l cc cng ngh ca Nht Bn.Phn "Cng ngh x l nc thi" gm t chng 5 n chng 10 do PGS. TS. Trnh Th Thanh bin son trnh by cc phng php c bn x l nc v nc thi. Tc gi tp trung phn l thuyt ca cc qu trnh x l sinh hc v minh ha bng cc v d tiu biu cho mt s ngnh sn xut cng nghip.Phn "Cng ngh x l cht thi rn" do TS. Trn Ym bin son gm 3 chng cui ca gio trnh. Phn ny bao gm cc bin php (h thng) thu gom cht thi rn th, nng thn; cng ngh x l cht thi (s dng li, ti ch, lm phn compost, sn xut kh sinh hc) v cng ngh chn lp cht thi.Cc tc gi xin chn thnh cm n nhng kin ng gp ca ng nghip v sinh vin v nhng khim khuyt trong ni dung cng nh hnh thc gip chng ti hon thin cun gio trnh ti bn ln sau.Cc tc giMC LCLI NI U............................................................................................................................ 1DANH MC CC BNG ......................................................................................................... 3Phn I CNG NGH X L KH THIChng 1 NHNG KHI NIM C BN .............................................................................. 41.1. CC NGUN TO RA KH THI V BI .....................................................41.2. CC DNG THI VO KHNG KH .............................................................4Chng 2 CC BIN PHP K THUT LM SCH KHNG KH ................................. 72.1. CC BIN PHP MANG TNH V M ............................................................72.2. CC BIN PHP MANG TNH CC B.........................................................72.3. CC BIN PHP CI THIN KHNG KH NI LM VIC .......................72.4. BIN PHP QUN L V VN HNH SN XUT ....................................9Chng 3 CC PHNG PHP V THIT B X L BI ............................................ 113.1. KHI QUT V BI V X L BI............................................................113.2. PHNG PHP X L BI BNG BUNG LNG ...................................123.3. PHNG PHP X L BI DA VO LC LY TM (CYCLON) ......... 143.4. PHNG PHP X L BI BNG LC MNG, LC TI ......................193.5. THU BI BNG CC PHNG PHP T ................................................213.6. KH BI TNH IN ......................................................................................28Chng 4 CC PHNG PHP X L HI V KH C ............................................ 334.1. KHI QUT V HI V KH C ...............................................................334.2. X L KH V HI BNG PHNG PHP THIU HY ........................334.3. PHNG PHP NGNG T ..........................................................................354.4. X L HI V KH THI BNG PHNG PHP HP PH...................364.5. X L KH THI BNG PHNG PHP HP TH .................................44Phn II CNG NGH X L NC THIChng 5 MT S VN C BN LIN QUAN N X L NC THI ............ 535.1. NHNG NH HNG CA NHIM NC GY RA I VI NGUN NC TIP NHN..................................................................................................535.2. CC IU KIN V CC PHNG N CNG NGH X L NCTHI..........................................................................................................................54Chng 6 CC PHNG PHP X L NC CP ........................................................ 566.1. KH ST BNG PHNG PHP LM THONG .....................................566.2. TRIT KHUN .................................................................................................56Chng 7 CC PHNG PHP X L NC THI ....................................................... 587.1. PHNG PHP X L C HC ............................................................... 587.2. PHNG PHP X L HO V HO - L ............................................. 61Chng 8 CC QU TRNH X L SINH HC.................................................................. 758.1. MT S VN CHUNG CA QU TRNH X L SINH HC ........ 758.2. CC PHNG PHP X L ........................................................................ 808.3. CC QU TRNH LC SINH HC ............................................................. 848.4. X L THM QUA T..................................................................................89Chng 9 MT S QU TRNH X L NC THI ...................................................... 929.1. X L CC CHT V C HO TAN ............................................................929.2. X L CC CHT HU C............................................................................939.3. X L V THI BN.......................................................................................94Chng 10 CC V D X L NC THI C TH .................................................... 10210.1. X L NC THI BNH VIN................................................................10210.2. X L NC THI CHA CRM .............................................................10410.3. X L CC HP CHT CYANIDES ..........................................................10510.4. X L NC THI NH MY BIA ..........................................................10610.5. X L NC THI CHA DU ................................................................10710.6. X L CHT THI NGUY HI ..................................................................110Phn III CNG NGH X L CHT THI RNChng 11 THU DN CHT THI RN ........................................................................... 11311.1. CNG C V PHNG TIN THU GOM CHT THI RN ................11411.2. H THNG, CC PHNG THC THU DN RC ...............................115Chng 12 PHN LOI V GIM KCH THC CHT THI RN.......................... 12612.1. PHN LOI CHT THI RN...................................................................12612.2. GIM KCH THC CHT THI RN....................................................128Chng 13 CH BIN CHT THI RN V BI THI................................................. 13213.1. CC MC CH S DNG CHT THI RN ........................................13213.2. CH BIN PHN VI SINH (COMPOST)....................................................13213.3. SN XUT KH SINH VT (BIOGAS)......................................................13713.4. BI CHA CHT THI RN (BI THI)................................................141TI LIU THAM KHO ...................................................................................................... 147DANH MC CC BNGBng 1. 1. Cc ngun v cc vt cht gy nhim ch yu ...................................................... 5Bng 1.2. Phn loi bi v hi kh c theo di kch thc ....................................................... 6Bng 3. 1. Cc phng php x l bi ..................................................................................... 11Bng 3. 2. Vng lc v hiu qu x l ca cc phng php .................................................. 11Bng 3.3. Nng sut lc bi ca cyclon n v cyclon t hp................................................. 18Bng 5.1. Cc phng php x l nc thi ............................................................................ 54Bng 5.2. X l nc thi bc 1 ............................................................................................... 55Bng 9.1. Cc thng s lm vic ca thit b lm c bn bng tuyn ni .............................. 97Bng 10. 1. Tiu chun thit k cc thit b khc nhau x l nc thi nh my bia ....... 107Bng 13. 1. Qu trnh phn huy sinh hc cht thi rn........................................................... 133Phn ICNG NGH X L KH THIChng 1NHNG KHI NIM C BN1.1. CC NGUN TO RA KH THI V BITrong thc t c hai ngun to ra kh thi v bi, l ngun nhim t nhin v ngun nhim nhn to gn lin vi cc hot ng ca con ngi.1.1.1. Ngun nhim t nhinCc hot ng t nhin c th lm tng hm lng bi ti mt thi im v mt khng gian no nh gi lc, bo sa mc mang theo bi t ct trn mt t tung vo bu khng kh. Ni la hot ng c th phun vo bu kh quyn mt lng bi v kh khng l. Nhng hin tng nh trn khng xy ra lin tc v pht tn nhanh ra mt vng rng ln lm gim hm lng bi v kh.Cc hin tng phn hy, thi ra ng thc vt xy ra thng xuyn cng thi vo khng kh mt lng kh c hi.Cc hin tng sm chp, my, ma, bc x trong h mt tri v v tr, thng qua cc phn ng phn hy hoc kt hp cc cht tn ti cn bng trong khng kh to ra cc cht c hi.Nhn chung nhim khng kh do thin nhin to ra v khi lng l rt ln song thng phn b trong mt khng gian rng v kh ng u nn t gy nguy hi.Mt khc cc sinh vt trn mt t, qua hng ngn vn nm quen v thchng c vi nhng thay i ni trn.1.1.2. Ngun nhim nhn toCc ngun nhim nhn to nguy him ch rt d xy ra hin tng cc b vi nng cao gy tc hi n ngi v cc sinh vt. Cc ngun v cc cht nhim nhn to c khi qut trn bng 1.1.1.2. CC DNG THI VO KHNG KH*Cc cht dng kh: l nhng cht iu kin thng thng tn ti th kh nh: CO, CO2,NOx,SOx,Cl2*Cc cht thi dng bi: l cc ht cht rn c phn tn trong khng kh c kch thc khc nhau (t 1/10 n hng nghn micromet).*Cc cht dng hi: th kh ca cc cht iu kin bnh thng l cht lng hoc rn. V d: hi benzen, iod, tetraetyl ch...*Cc cht dng soi: l tp hp cc phn t cht lng hoc cht rn to thnh ccht nh li ti phn tn trong khng kh.Cc cht thi l kh, hi, bi hay sol c tc hi t hay nhiu s ph thuc vo bn thn tnh cht ca chng.Bng 1. 1. Cc ngun v cc vt cht gy nhim ch yuCht nhimNgun nhim

Oxit cc bon (CO, CO2)- Cc nh my nhit in- Cc ngnh cng nghip s dng nng lng l t nhin liu- Giao thng vn ti- Cc l t rc v dn dng- Phn hy ym kh

Bi than, troCc ngun t nhin liu thi cng vi kh cacbon oxit

Bi beriliCh ha qung v luyn kim

Bi uraniumCh ha qung

Hp cht cha kim loi c c tnh cao- Cc c s luyn kim- Cc c s sn xut ha cht- Cc c s sn xut thuc tr dch hi- S dng cc sn phm thuc tr dch hi

Cc hp cht cha clo- Thuc tr su- Cc c s sn xut ha cht- Cc c s sn xut giy v bt giy- Kh trng bng clo v cc hp cht cha clo hotng

Flo v cc hp cht cha flo- Cc c s sn xut ha cht- Cc c s sn xut phn ln t apatit v photphorit..- Cc c s luyn kim

Hydrocacbon- t nhin liu- Cng nghip sn v trang tr bng sn.- Cc c s sn xut linh kin cn lm sch bng dung mi hu c- Cc c s sn xut ha cht hu c- Luyn kim

Nit oxit- t nhin liu- Cc nh my ha cht- Cc c s sn xut phn m, phn tng hp NPK

Lu hunh oxit- Cc c s sn xut ha cht- Cc nh my nhit in- Luyn kim- Cc cng on t nhin liu khc

Cht nhimNgun nhim

Cc hp cht c cha phi pho- Cc c s sn xut thuc tr dch hi- S dng thuc tr dch hi

Bi khong v c- Cng nghip sn xut xi mng- Cng nghip khai khong- Giao thng vn ti- Xy dng

Bi phng x- Cc v th ht nhn- S r r ca cc c s nng lng ht nhn

Hi kim, hi axit- Cc c s sn xut ha cht- Cc c s s dng axit v kim trong sn xut

Bi ch- Cc c s sn xut acquy- Giao thng vn ti

Dicyan v HCN- Cc c s m kim loi- Khai thc, trch chit vng, bc v cc kim loi

C nhiu cch phn loi bi, hi v kh c. Di gc thu gom v tch lc, ta c th phn loi theo di kch thc (bng 1.2).Bng 1.2. Phn loi bi v hi kh c theo di kch thcDi kch thc(m) c tnhBi 0,1 1000-2000 Pht sinh trong qu trnh p, ph, n, mikhoan... cc cht rn nh , qung, than, kim loi. Mt s bi c dng si c ngun gc ho hc, thc vt hoc khong. Cc bi ln c lng do lc trng trng. Cc bi nh c khuynh hng bay l lng trong khng kh.Khi I 0,001 0,1 c to ra do ngng t cc ht cht rn trong qu trnh lm nng chy kim loi hoc cc phn ng ho hc.Khi II 0,1 0,1 c to ra do qu trnh t chy nhin liuSng 0,01 10,0 L sn phm ca qu trnh ngng t cc ht cht lngHi 0,005 L th kh m trong iu kin bnh thng chng th lng hoc rnKh 0,0005 L dng vt cht m trong iu kin nhit v p sut thng thng chng khng tn ti th lng hoc rnChng 2CC BIN PHP K THUT LM SCH KHNG KHGia thin nhin v con ngi trn hnh tinh ca chng ta lun c mt mi quan h mt thit. Nhng tc ng n thin nhin gy ra do nhim khng kh c quan h nhn qu i vi hot ng sng ca con ngi. l s sa mc ho, s nng ln ca tri t, xi mn, bo, lc... gim thiu s nhim khng kh, c th c nhng bin php sau:2.1. CC BIN PHP MANG TNH V M- Hn ch tc ng ca con ngi vo thin nhin nh: Hn ch t rng, hn ch khai thc rng, khong sn nhm gim nh hng n s cn bng vn c ca kh quyn.- Chng sa mc ha, hoang ha.- Trng cy xanh, trng rng, trng rng cy m ven b bin chung s xm ln ca ct, hi mui bin.2.2. CC BIN PHP MANG TNH CC B- Ci tin cng ngh sn xut v khai thc: Bin php ny nhm gim cc cht thi v cc cht thi c gy nhim mi trng khng kh.- Thay i nguyn, nhin liu cho sn xut trnh hoc gim thiu thi cc cht c hi vo khng kh.2.3. CC BIN PHP CI THIN KHNG KH NI LM VIC2.3.1. Thng giNhim 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.1. Thng gi chungMc 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.Nhc im ca bin php ny l to ra mc khng ng u ca iu kin v sinh ti nhng im khc nhau trong khng gian nh xng; ng thi d a c hi t vng ny sang vng khc. V vy, mt trong nhng yu cu cn thit khi p dng bin php ny l phi n nh c cc ngun pht thi c hi. Hin tn ti mt s s h thng trao i khng kh trong phng nh sau:+ Thi trn ht di. + Thi trn ht trn.+ Thi di ht trn. + Thi di ht di.Ty tng trng hp m p dng s ny hay s khc, nhng phi tun ththeo nguyn tc l dng khng kh phi i theo trnh t:Khng kh sch Vng th Vng to c Ming Ht Thi2. Thng gi cc bMc ch ca thng gi cc b l thu gi cc kh, hi c ngay ti ngun pht sinh. y l bin php hiu qu nht trong vic m bo trong sch khng kh cho vng lm vic.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.3. Thng gi chng nng* Khi nim v cn bng nhitTrong qu trnh hot ng, con ngi lun c s trao i v nhit vi mi trng. Mc trao i nhit tiu chun i vi mt ngi trong iu kin ngh ngi l 100 Kcal/gi. V ma h, thi tit nng nn ch c con ng duy nht cn bng nhit l thot m hi. thu c hiu qu lm mt bng bc hi m hi th phi c cc iu kin sau:+ m ca khng kh thp.+ C gi vi vn tc ph hp.Ti nc ta, m trung bnh tng i cao. Do vy tng hiu qu bc hi mhi phi dng gi c tc ln, v d:+ i vi h iu ho khng kh: v = 0,25 - 0,38 m/giy.+ i vi lao ng: v = 5,00 - 10,00 m/giy.* Cc gii php chng nngTy theo mc , yu cu khc nhau v v sinh cng nghip m p dng cc gii php thng gi chng nng khc nhau. C th chia lm hai loi:+ Gii php thng gi t nhin v cch nhit.+ Gii php thng gi cng bc.Thng gi t nhin l li dng cc yu t ca t nhin nh vn tc gi tri, chnh lch t trng ca khng kh to ra cc dng kh vo ra mt cch hp l. Ti nc ta, thng gi t nhin ch yu l dng gi tri. Do vy vic m cc ca n gi, thot gi vi t l ln l vic lm rt quan trng. Cc nghin cu gn y cho thy t l m ca phi t 40 n 60% din tch tng mi m bo thng gi t nhin theo phng nm ngang c hiu qu.Mt vn quan trng khc l vic hn ch bc x nhit mt tri truyn qua mi nh. V ma h, lng nhit truyn qua mi c th ln ti 110 - 120 Kcal/m2. Mt trong nhng bin php c th p dng l phun nc ln mi.Thng gi cng bc c s dng khi thng gi t nhin khng cn kh nngp ng c vn cn bng nhit. Thng gi cng bc nhm to ra vn tc gi thi thch hp, kt hp vi cc thng s nh nhit , m... a vi kh hu v trng thi t nhin d chu.Trong gii php thng gi cng bc th iu ha khng kh l hnh thc cao nht ca k thut thng gi nhm p ng ch ng cc thng s vi kh hu trong nh m khng ph thuc vo kh hu ngoi tri.Trong cng nghip, ngoi yu t vn tc gi thi cn c th h nhit khng kh lm tng hiu qu lm mt. Mt trong nhng bin php n gin c th p dng l lm mt bng bc hi on nhit. Nguyn l chung ca bin php ny l cho dng khng kh i qua bung phun nc hoc lp mng t. Nhit ca khng kh lm nc bay hi v t n h nhit xung nhng m tng i tng ln. Bin php ny c p dng cho nhng vng c kh hu nng, kh nh min Trung v min Nam nc ta.2.3.2. S dng cy xanhCy xanh c tc dng rt ln trong vic hn ch nhim khng kh nh thu ht bi, lc sch khng kh, gim v che chn ting n, gim nhit khng kh. Mt s loi cy xanh rt nhy cm vi nhim khng kh, cho nn c th dng cy xanh lm vt ch th pht hin nhim. V th nn trng nhiu cy xanh trong khun vin v xung quanh cc nh my, dc cc ng giao thng, trong khu m gia cc khu cng nghip, thng mi v dn c. T l din tch cy xanh trn din tch khu cng nghip cn t t 15 n 20%.2.3.3. Gii php cng nghy l bin php nhm gim thiu nhim khng kh c coi l c bn, v n cho php h thp hoc loi tr cht nhim khng kh c hiu qu nht. Ni dung ch yu ca bin php ny l hon thin cng ngh sn xut v p dng chu trnh kn.Bin php cng ngh bao gm vic s dng nhng cng ngh sn xut khng c hoc c rt t cht thi. N cng bao gm vic thay th cc nguyn liu, nhin liu thi ra nhiu cht c hi bng nhng nguyn, nhin liu khng hoc t thi c. V d nh thay th than bng kh t. N cn bao gm c vic s dng cc phng php sn xut, gia cng t sn sinh ra cht c hn nh gia cng kh nhiu bi bng gia cng t t bi hn hay thay v t bng than th t bng in...To ra mt chu trnh sn xut kn c tc dng loi tr cc cht nhim khng kh ngay trong qu trnh sn xut. Bng cch s dng tun hon mt phn hay ton b cc kh thi trong quy trnh sn xut, hoc ti s dng chng cho vic sn xut sn phm khc s gim bt hoc trit tiu hon ton kh thi.2.4. BIN PHP QUN L V VN HNH SN XUTVic vn hnh v qun l thit b my mc hoc nh quy trnh cng ngh cng lmt bin php khng ch nhim khng kh. Nghim tc thc hin ch vn hnh, nh mc chnh xc nguyn vt liu, chp hnh ng quy trnh cng ngh s lm cho lng cht thi gim xung v c iu kin qun l cht ch ngun thi v lng cht thi.Chng 3CC PHNG PHP V THIT BX L BI3.1. KHI QUT V BI V X L BINh ni n phn trn, bi l nhng ht cht rn c kch thc cng nh t trng khc nhau phn tn trong khng kh. x l lc sch bi trc khi thi ra mi trng ngi ta nghin cu v s ng nhiu cch khc nhau. Mi cch (phng php) ph hp vi cc loi bi, kch thc bi khc nhau v c nhng u nhc im ring. Chnh v vy m ty thuc vo i tng bi, ngi ta chn phng php x l ph hp.Cc phng php x l bi c th cha thnh cc nhm sau nh trn bng 3.1.Bng 3. 1. Cc phng php x l biLcDp bng ncDp bng tnh inKh bi da vo lc ly tmKh bi da vo trng la

- Thng lc gm- Lc c vtm- Lc ti (mng)- Dn ma- Sc kh- a quay- Lc tng kiuVenturiLc tnhin- Thit b s dng lc qun tnh.- Thit b s dng lc ly tm (cyclon).Thit b quayBung lng bi

Trn c s phn loi cc phng php x l, ta c th chia cc thit b x l bi lm 6 ng chnh nh sau:1. Lc c kh 4. Thit b lc tnh in2. Thit b mng lc 5. Thit b lc t3. Thit b hp th 6. Thit b bung tHai loi u dng x l bi. Thit b lc tnh in v lc t c th dng x l bi hoc hi kh c. Hai thit b sau hay c dng x l kh.c trng v hiu qu x l bi ca cc kiu thit b c khi qut trn bng 3.2.Bng 3. 2. Vng lc v hiu qu x l ca cc phng phpSTTThit b x lKch thc ht ph hpHiu qu x l (%)

1Thng lng bi2000 10040 70 %

2Cyclon hnh nn100 545 85

3Cyclon t hp100 565 95

4Lc c vt im100 10n 99

5Thp lc t100 0,185 99

6Lc ti (mng lc)10 285 99,5

7Lc tnh in10 0,00585 - 99

C th ha bng 3.2 ta c th tham kho minh ha trn hnh 3.1.

Bng 3.2 v hnh 3.1 cho thy rng cc thit b x l bng lc qun tnh v cc cyclon rt tin tch cc ht bi tng i ln. Loi cyclon t hp c hiu sut ln nht. Dng cc thit b lc in, thit b lc hnh ng tay o v cc thit b lc bi loi t c th t c tinh lc kh cao.Thit b lc bi loi t ch dng khi cht kh cn x l chu c nhit thp v m. Trong trng hp ny cc thit b lc bi loi t c nhiu u im hn so vi thit b lc in ch thit b gin n v r tin. Ngoi ra, ngi ta cn dng cc thit b lc t lc sch kh khi bi, khi v m (ti 90%). ng dng thit b lc bi loi t trong nh my c nhiu kh khn v y qu trnh tinh lc c lin quan ti vic thu gom v thi mt lng ln nc c tnh axit. Thit b lc in l mt loi thit b lc sch bi c hiu sut cao; trong mun lc cc loi kh kh ta dng loi thit b lc in thanh bn, cn lc sch cc loi bi v hi m kh hp th, cng nh lc sch c tt hn, ta dng loi thit b lc in kiu ng v khi cn lc sch mt th tch kh ln th dng thit b lc in t hp, r.Tm li, mun chn c thit b tch bi v lc sch kh c hiu qu, phi xut pht t cc yu cu chnh sau:1. Thnh phn ht bi v kch thc ht ca n.2. Trng thi v thnh phn ca kh.3. tinh lc kh cn thit.3.2. PHNG PHP X L BI BNG BUNG LNG3.2.1. Nguyn tcS lng bi bng bung lng l to ra iu kin trng lc tc dng ln ht bi thng lc y ngang ca dng kh. Trn c s ngi ta to ra s gim t ngt lc y ca dng kh bng cch tng t ngt mt ct ca dng kh chuyn ng. Trong thi im y, cc ht bi s lng xung. lng c hiu qu hn, ngi ta cn a vo bung lng cc tm chn lng. Cc ht bi chuyn ng theo qun tnh s p vo vt chn v ri nhanh xung y.3.2.2. Cu to ca bung lngMt bung lng n, kp c cu to nh hnh 3.2.1. B mt ct ngang ca bung lng c tnh theo cng thc:trong : a l chiu rng ca bung lng h l chiu cao ca bung lngV l lu lng kh qua bung lngw l vn tc dng kh qua bung lng.Nh vy, khi thit din ca bung lng cng tng th vn tc dng kh trong bung lng cng gim.2. B mt rng cn thit (F) tnh theo cng thc: y: w1 l vn tc lng biV l lu lng dng kh v bi.Thi gian lng ca ht bi c tnh theo cng thc:t = h /w1 (s) Th tch lm vic ca bung lng (VLV):VLV = V.t (m3)Chiu di cn thit ca bung lng (l):l = F / a = VLV /h. a (m)3.2.3. Cu to ca bung lng nhiu tngBung lng nhiu tng l mt dy cc bung lng n l ni tip nhau. Tng tngn l hot ng ging nh bung lng n. Nh vy chiu dy tng cng:trong : ni l tng th ihi l chiu cao tng th iTm li, bung lng bi l mt loi thit b thu bi a vo lc trng lc v lc qun tnh thu gi bi. Vi thit b loi ny ngi ta c th thu gom cc ht bi ckch thc ln hn 10 m. lm sch kh trong cc l t ta cng c th s dngthit b bung lng nhiu tng. Mc d bung lng bi l bin php r tin nhng thitb ca n cng knh v hiu qu x l thng l thp nht so vi cc phng php khc N hay c s dng lm sch s b.Di y l mt s m hnh thit b thu bi bng trng lc (hnh 3.3a, 3.3b).3.3. PHNG PHP X L BI DA VO LC LY TM (CYCLON)3.3.1. Nguyn lKhi dng kh v bi chuyn ng theo mt qu o trn (dng xoy) th cc ht bi c khi lng ln hn nhiu so vi cc phn t kh s chu tc dng ca lc ly tm vng ra pha xa trc hn, phn gn trc xoy lng bi s rt nh.Nu ta gii hn dng xoy trong mt v hnh tr th bi s va vo thnh v v ri xung y. Khi ta t tm dng xoy mt ng dn kh ra, ta s thu c kh khngc bi hoc lng bi gim i kh nhiu.Hnh 3.4.a. ng i v cc lc tc dng trong cyclo ca dng bi kh3.3.2. Cyclon nMt eyclon n c th m phng theo hnh 3.4.bHnh 3.4.b. Mt ct ng v mt ct ngang ca mt cyclon n1. Tc lng ca ht bi trong cycton c tnh theo cng thc:trong :d: ng knh ht bi (m).Pl: Khi lng ring ca ht (kg/m3)P2 Khi lng ring ca kh mang (kg/m3)v2 : H s nht ng hc ca kh (m2/s)U: Tc Vng ca dng kh trong cyclon (m2/s) D: ng knh phn v hnh tr ca cyclon (m)2. ng knh phn hnh tr ca cyclon c tnh theo cng thc:D = 2.(R1 +1 +R) (m)trong : R1 l bn knh ng dn kh ra (ng trong hnh tr);1 l dy ca v ng dn kh ra; R l khong cch tnh theo bn knh giang dn kh ra v thn cyclon.trong : V l lu lng kh qua hay nng sut ca cyclonwr l vn tc dng kh i ra khi cyclon (trong cng nghip wr thng ly t 4 - 8m/s).3. Kch thc ca ng vong vo thng l hnh ch nht c chiu cao h v chiu rng b. Thng thng t l h/b bng k v bng t 2 n 4.trong : wv l vn tc dng kh vo trong ng cyclon (thng bng 18 - 20 m/s).4. Th tch lm vic ca cyclonVLV = V. t (m3)trong t l thi gian lu ca dng kh trong cyclon.trong w l tc gc ca dng kh trong cyclon, w = wrtb/ Rtb

wrtb l vn tc trung bnh dng kh ra khi cyclonpK l t trng ca kh v b l gc vo ca dng kh. R2 l bn knh v phn hnh tr, Rtb l bn knh trung bnh ca phn hnh tr ca cyclon.5. Chiu cao ca phn hnh tr Httrong Vh: Th tch hiu dng ca phn hnh trVlv : Th tch lm vic ca cyclon1: dy ca v ng dn kh rawtb: Vn tc trung bnh ca dng bi v kh thi trong cyclon.R1, R2: Bn knh ca ng dn kh ra v bn knh v phn hnh tr ca cyclon.k: H s ph thuc c tnh ca dng kh bi thi.Hnh 3.5.a v 3.5.b. Thit b dng tip tuyn (a)v thit b dng trc (b)6. Chiu cao phn hnh nntrong :

Hn = (R2 R0). tg 0

R0 l bn knh l thot bi (thng l 0,2 n 0,5 m),0 l gc nghing gia bn knh v ng sinh (thng l 50 600).C hai cch a dng kh vo cyclon to ra chuyn ng xoy l dng dng tip tuyn v dng dng trc nh trn hnh v 3.5.a v 3.5.b.Trong thc t ngi ta thng lp thnh t hp nhiu cyclon n li tng cng hiu qua x l kh thi (xem hnh 3.6). T hp cyclon thng gm cc cyclon n c ng knh t 40- 250 mm, ghp thnh cm song song vi nhau. Thit b kiu cyclon c th s dng x l dng kh bi c nhit n 4000 C nhng nng bi khng cao.Nhc im chung ca cyclon l khng th lc sch kh khi cc ht bi rt nh, nng lng tiu th lc ln v thnh thit b b mi mn nhanh do do nhy v ti trng cng s gim xung. Ta c th tham kho nng sut lc ca cyclon (m3/h) bng 3.3.Loi

Bng 3.3. Nng sut lc bi ca cyclon n v cyclon t hpCyclon Nng sut lm vic theo ng knh ca Cyclon (mm)400500600700800

n1450-16902270-26403260-38104400-51805800-6760

Kp--4540-52906520-76208800-1040011600-13500

Ba------13200-1550017400-20300

Bn5800-67609080-1060013000-1520017600-2070023200-27000

7. Hiu sut lm sch bi ca cyclonHiu sut lm sch ring phn:3.6.

trong :i l thnh phn ca cc loi (kch thc) bi.G, Gd, Gc l khi lng bi c x l, khi lng bi ban u v khi lng bi cn sau khi x l.GRP, GRPd, GRPc l khi lng bi ring phn c x l, khi lng bi ring phn ban u v khi lng bi ring phn cn li sau x l.Gin hiu qu ca phng php thu bi bng cyclon c th hin trn hnhHnh 3.6. Gin hiu qu ca thit b thu bi cyclonNgoi thit b cyclon kiu kh ngi ta cn c th s dng thit b cyclon t lm sch bi nh hnh 3.7.3.4. PHNG PHP X L BI BNG LC MNG, LC TI3.4.1. Nguyn lDng kh v bi c chn li bi mng hoc ti lc; ti (mng) ny c cc khe (l) nh cho cc phn t kh i qua d dng nhng gi li cc ht bi. Khi lp bi dy ngn cn lng kh i qua th ngi ta tin hnh rung hoc thi ngc thu hi bi v lm sch mng.3.4.2. Cu to v vn hnhMng lc l nhng tm vi (n) c t trn mt gi l nhng tm cng an hoc tm cng lin c c l.Ti lc bng vi, n c dng ng mt u h kh i vo cn u kia khu kn. ti c bn hn ngi ta thng t trong mt khung cng bng li kim loi hoc nha.Nng sut lc ca thit b ph thuc vo b mt lc, loi bi v bn cht, tnh nng ca vt liu lm ti (mng).Mt b thit b t hp cyclon c dng nh hnh 3.8:

1. Din tch lc c tnh theo cng thc- i vi ti lc:- i vi mng lc: S = a.b trong :V l lu lng kh (nng sut lc) qua ti (mng) (m3/s).v l cng lc ca mt m2 b mt (m3/m2.h). Thng thng v c chn t 15n 200 m3/ m2.h. l hiu sut lm vic ca b mt lc, thng thng c ly khong 85 %.D l ng knh ng lc.l l chiu di ng lc.a l chiu rng ca ti. b l chiu di ca ti.2. Lc cn ca ti (mng) c tnh theo cng thcP = A. vn (N/m2)trong A l h s thc nghim ph thuc vo nguyn liu lm ti (mng), c k n bo mn v cn bn. A thng dao ng t 0,25 n 25,00. n l h s thc nghim thng thng bng 1,25 n 1,30.Tc dng cao, xp > 1 mm : qun tnhTc dng nh. xp > 1 mm : khuch tnHnh 3.9. M hnh ng i ca ht bi v thit b lc bi dng ng lc v ti lcB phn chuyn ng c khHnh 3. 10. Thit b lc ti c s dng ph binS dng lc bng mng hoc bng ti c th cho hiu qu lc n 98-99%. Vi nhng ht bi c kch thc 1 m, hiu qu lc ti gn 100%. Phng php ny cng loi c cc ht bi nh n hng 0,01 m.3.5. THU BI BNG CC PHNG PHP TCc phng php t thng c s dng cho nhng ni bi mang m cao hoc khng kh ti ni lm vic khng ng u v nhit v m. Nguyn tc ca phng php ny l dng khng kh cha bi phi c i qua mt mi trng lng hoc mng hi nc tng kh nng lng xung ca ht bi. C rt nhiu cch p dng nguyn tc ny, di y chng ta s xem xt mt vi phng php hay c s dng trong cng nghip.3.5.1. Phng php dp bi bng mng cht lng1. Nguyn lDng kh c cha bi i qua mng cht lng (thng l nc). Cc ht bi gp nc s b dm xung hoc cun bm theo mng nc, cn dng kh i qua. Nc thng c i t trn xung, cn dng kh i t di ln.2. Cu to v vn hnh ca thit b* Dn ma: y l thit b n gin nht dp bi nhng li c hiu qu cao. Lng nc phun vo c th quay vng tr li sau khi lng bn bi. Thit b ny thng dng trong cc nh my xi mng hay cc x nghip nghin qung.* Thp a chng: y l mt kiu thp dp bi khc rt c hiu qu.Trong cng nghip, thit b lc bi qua mng cht lng thng c t sau h thng bung lng bi nhm mc ch thu gom nhng ht bi qu nh khng b gi li bung lng. Kch thc thit b thng c b rng > 1m; su v cao > 1,5 m; ng knh ng thi > 600 mm; chiu cao ng thi ch nn hn ch < 5 m thun tin lmv sinh. Cu to c bn ca dn ma v thp a chng c m t trn hnh 3. 1 1.Hnh 3.11. Kiu dn ma (a) v kiu thc a chng (b)Trn c s dp bi bng mng cht lng ngi ta ch ra mt s thit b loi ny c dng nh sau (hnh 3.12).

Hnh 3. 12. S thit b dp bi bng mng cht lng3.5.2. Phng php sc kh qua cht lng (nc) - Phng php si bty l mt trong cc kiu tch bi ra khi kh thi bng phng php t c hiuqu cao (vi bi c ng knh ln hn 5 m, hiu sut lm sch kh t ti 99%).1. Nguyn lKh cha bi i qua mng c l ri qua lp cht lng di dng cc bt kh. Bi trong cc bt kh b thm t v b ko vo pha nc to thnh cc huyn ph ri c thi ra ngoi. Kh sau khi c lm sch s thi ra mi trng. Thit b lm sch kh kiu ny ph hp vi nng bi khong 200 n 300 mg/m3; cng sut c th ln ti50.000 m3/h.2. Cu to v hot ngCu to n gin ca mt thit b si bt c m t hnh 3.13.

Hnh 3. 13. Cu to ca thit b si btKh c i t di ln thng qua mt mng phn phi, li qua nc, qua mng (li) ra ri ra ngoi. Nc c cp lin tc vo ca nc v ly ra y cng vi huyn ph bi.* Din tch mng (li) c tnh theo cng thc: S = V / wtrong : V l lu lng kh qua thit bw l vn tc kh.Vn tc kh thng t 0,7 n 3,5 m/s. Nu w qu nh s khng to c bt si ln; Khi w ln qu s ph v lp bt (thnh phun). Vn tc w qua b mt t do ca mng (li) tng i n nh khong 2m/s.*ng knh l li khong t 2 n 8 mm* Chiu cao ca lp bt trn li (mng) tnh theo cng thc: H = k1.w(H0+ k2) + 2H0trong : w l vn tc kh i qua li.k1 v k2 l h s thc nghim (k1 = 0,35 v k2 = 0,075 khi din tch t do ca l li nh hn 18%; k1 = 0,65 v k2 = 0,015 khi din tch ca l li ln hn 18% v nh hn 30%).H0 l chiu cao ca lp cht lng ban u.* Hiu sut lm sch c tnh theo cng thc:trong : G0 l hm lng bi ban u.G l hm lng bi cn li trong dng kh sau khi i qua thit b.Trong thc t, thp lc thng c lm nhiu tng lc bi c sch hn. Cc thp lc nhiu tng thng c p dng x l kh v bi ng thi, c bit trong trng hp hm lng kh nh. Di i l s thp lc si bt.

Hnh 3. 14. S thp lc si bt3.5.3. Phng php ra kh ly tmThc t y l thit b kt hp lc ly tm ca cyclon vi s gp bi ca nc. Nc c phun t trn xung theo thnh hnh tr ca thit b, ng thi kh c thi theo dng xoy t di i ln. Bi vng ra pha thnh b nc cun theo i xung ca thot di y (m hnh ca thit b cyclon t c minh ho trong mc 3.3) (hnh3.8).3.5.4. Phng php ra kh kiu Venturi1. Nguyn lDng kh c dn qua mt ng tht, ti y tc dng kh tng ln cao (50 -150 m/s). Khi vt qua u cp cht lng ng s ko theo dng sol. Nhng ht cht lng nh b s lm t bi cun theo v ngng hi thnh dng bn i ra theo ca di v dng kh ra s l kh sch.2. Cu to v vn hnhThit b tch bi khi dng kh thi kiu Venturi c m t trn hnh 3.15. Kh c dn vo ca 1 qua c tht 2, ti y c t ca cp nc. Sau khi dn qua ca 3 kh i vo bung lc sol 4; ti y c trang b h thng tch sol l nhng tm li t xin so vi thnh bung. Sol nc ln bi t tch t li phn y v c thi ra ngoi theo ca 6. Kh sau khi tch sol v bi c thot ra ngoi theo ca 5.

Hnh 3. 15. Thit b tch bi khi dng kh thi dng VenturiNgc li vi kiu Venturi ngi ta cn dng dng nc thay v dng kh trong thit b ra kh. Dng cht lng c vn tc ln i qua ca tht s to mt p sut m khong khng gian gia dng nc v thnh ca tht; kh thi s b cun vo qua ca tht, tip xc vi dng phun ca cht lng v qu trnh tch bi xy ra ging nh nguyn l trong thit b Venturi. Nc (cht lng) sau khi tch phn ln huyn ph bi cc ngn b ti phn y ca thit b c s dng tun hon tr li. Kh i ra l kh sch. i vi thit b kiu ny, vn tc ca cht lng thng vo khong t 20 n 30 m/s; tc dng kh vo t 10 n 20 m/s.Hnh 3.16 di y m t cch i ca cht lng ra v dng kh thi qua ca tht.Hnh 3. 16. Cch i ca cht lngCc thit b tch bi khi kh kiu ny c th lp lin tip nhau qua nhiu bc tutheo yu cu sch ca kh ra.Trong cc loi thit b ra kh t, thit b kiu Venturi t hiu qu thu bi cao nht v c s dng rng ri trong k ngh. Di y l mt s thit b tch bi kiu t khc hay c s dng:

Hnh 3.17. Mt s thit b ra kh3.5.5. Ra kh kiu dng xoy1. Nguyn 1Dng kh c tc ln thi trc tip vo b mt cht lng theo mt gc xin; di p lc ca dng kh, cht lng s b tung ln, kh v cht lng tip xc vi nhau; bi b thm t s gi li trong cht lng v kh sch i ra ngoi.2. Cu to v vn hnhCc kiu thit b ra kh dng xoy c m t nh trn hnh 3.18. i vi kiu1 v 2 tuy cu to c khc nhau nhng qu trnh vn hnh tng t nhau. Dng kh v bi c dn qua ca vo bung ra (vi vn tc thng t 10 n 15 m/s). Do cu to c tm chn nh hng nn dng kh tip xc vi b mt cht lng di mt gc xin. Dng kh v cht lng c tip xc vi nhau trong vng tip xc. Hu ht bi s c gi li trong lng cht lng; dng kh cha sol c i qua mng tch sol v i rangoi theo ca ra. Huyn ph bi c thng xuyn ly ra theo ca thi.Hnh 3.18. Cc kiu thit b ra xoyKiu th 3 c trang b cnh hng dng hnh xon c nn lm tng thi gian tip xc gia dng kh bn v sol nc dn n hiu qu lm sch c tng ln. Mt khc do thi gian dng kh v sol i trong cnh nh hng di hn nn hu ht cc sol c lng li nn khng cn trang b thm mng tch sol. Kh bn i vo thit b theo mt ng lp xin vi thnh thit b; sau khi tip xc vi b mt cht lng s i vo cnh hng dng. Kh sch i theo ca ra. Huyn ph bi c nh k ly ra theo catho bi.u im ca cc thit b ra xoy l bi c ko vo trong phn nc ra tun hon, v th ta ch cn b sung lng nc tht thot nn s tit kim c nc ra v phn nc phi x l cng t i.3.5.6. Ra kh kiu a quay1. Nguyn lBi trong dng kh i qua h thng kh bi gm nhiu tm c l hay li bng kim loi. Nhng tm li ny lun lun c thm t bng mt cht lng thch hp v quay trn u trong mt khng gian hnh tr. Nhng ht bi trong dng kh gp b mt cht lng s b lm t v b gi li ri tri theo nhng git nc ri xung y.2. Cu to v vn hnhKh thi c dn vo thit b theo ca "kh vo" 1 pha di; sau khi i qua h thng a quay 5 s i ra ngoi theo ca "kh thot" 2. Cht lng c phun vo a trn cng bng h thng phun 3 v chy u xung cc a pha di. Bi b thm t s chy theo dng cht lng i xung pha di v c thng xuyn tho ra theo cathot 4 (hnh 3.19)Hnh 3. 19. Thit b ra kh kiu a quay3.6. KH BI TNH IN3.6.1. Nguyn lTrong mt in trng u, c s phng in ca cc in t t cc m sang cc dng. Trn ng i, n c th va phi cc phn t kh v ion ha chng hoc c th gp phi cc ht bi lm cho chng tch in m v chng s chuyn ng v pha cc dng. Ti y chng c trung ha v in tch v nm li . Li dng nguyn l ny ngi ta s thu c bi t cc tm in cc dng v kh i ra l kh sch bi.Di y chng ta s xem xt cch di chuyn ca nhng ht bi trong mt in trng u (hnh 3.20) v qu trnh hot ng ca mt h thng lng bi bng tnh in (hnh 3.21).

Hnh 3.20. M phng ng i ca ht bi trong in trngHnh 3.21. Qu trnh lng bi tnh in3.6.2. Cu to v hot ngThng thng dp bi bng in trng, ngi ta lm nhiu tng in cc lin tip nhau. in cc m thng l mt dy dn trn, khi hot ng xung quanh dy dn thng c qung sng do in t ion ho cc phn t kh khi n chuyn ng qua in cc dng nn cn gi l in cc qung sng. M hnh cu to n gin ca mt thitb lc bi tnh in c m t trong hnh 3.22.Hnh 3.22. M hnh thit b lc in ng v lc in tmDi y l mt s m hnh thit b lc bi tnh in hay c s dng trong xl kh thi cng nghip.B lc tnh in dng ng

B lc t in dng tmHnh 3.23. Cc loi thit b lc tnh inKhong cch gia hai in cc khc du thng t 10, 15 n 20 cm; n phthuc vo in th, cch in v cng dng in.1 i vi thit b lc in tm (li)* S in cc dng (in cc lng) c hnh tm hoc li ltrong :2.l l khong cch gia hai in cc cng du a l chiu cao ca cc tng in cc.* S in cc m (dy hay in cc qung) ltrong b l chiu rng ca nhm in cc.* Th tch lm vic ca thit btrong :V l nng sut lm vic ca thit b. t l thi gian lng ca bi.* Tc ca dng kh:trong h l chiu cao lm vic ca thit b.2. i vi kiu thit b lc in hnh ng* Th tch ngtrong l l chiu di ng; D l ng knh ng.* S ng c tnh theo biu thc:trong Vl l th tch lm vic.

n = Vl /V3. Tnh in th v cng dng ti cc in ccU = E. ltrong :E l gradien in th (kw/cm) v s c chn nh sau:- i vi kh lnh: E t 4:3 n 4,5 kv/cm.- i vi kh nng: E t 3,8 n 4,0 kv/cm.I = i.ltrong : i l mt dng theo chiu di (A/m)l l chiu di hot ng ca in cc m (m) I: cng dng in trnh hin tng on mch gia cc in cc trong thit b lc tnh in, ngi ta to ra mt in trng khng ng nht m th hiu ca n gim dn khi cng xa in cc m. S ph thuc ca mt dng vo khong cch gia cc in cc c th tham kho bng sau:

4. Cng sut tiu tn cho ton b h tc tnh theo biu thctrong :U v I: l in p v dng cn cho qu trnh lcK: l h s chnh lu ng: l h s hu ch (= 0,8)Cos: bng t 0,7 n 0.75P1: l cng sut tiu tn cho cc hot ng ph nh rung bi... l/1,41: l h s bin in p hiu dng.Nhn chung, so vi cc thit b lc in tm th thit b lc in ng c u im l in trng c hiu sut cao hn v s phn phi kh tt hn do lm tng hiu sut lc. Tuy nhin thit b lc ng lp rp phc tp, kh lm chn ng cc in cc m do phi m bo c nh tm ca chng mt cch chnh xc cng nh tn nhiu nng lng trn mt n v chiu di ca dy dn. Thit b lc in tm th ngc li d lp rp hn v d dng lm chn ng cc in cc m hn. Do vy, lm sch kh kh, lm sch bi kh thm t ngi ta hay dng thit b lc in thanh bn (tm). Cn loi cc ht lng ra khi m (khng cn lm chn ng in cc qung sng) v m bo c lm sch kh cao, ngi ta dng thit b lc in ng.Chng 4CC PHNG PHP X L HI V KH C4.1. KHI QUT V HI V KH CKhc vi bi v sol, kh v hi n ti di dng cc phn t ring bit ln vo khng kh theo cc chuyn ng chaose. iu kin bnh thng hi c th ngng t c, cn kh th ch ngng t c khi to c p sut hoc nhit ph hp (p sut cao, nhit thp).X l hi hoc kh thi c hi c th tin hnh bng cc phng php tiu hy, ngng t, hp ph hoc hp th.4.2. X L KH V HI BNG PHNG PHP THIU HY phn hy mt cht dng kh hoc hi c hi cho mi trng thnh mt hay nhiu cht khc t hoc khng c hi c th thc hin bng ngun nhit - phn hy nhit hoc phn hy thng qua cc phn ng ha hc, hoc kt hp c hai nh phng php t.4.2.1. Thiu hy bng nhitPhng php ny ph hp vi kh thi cha cc hp cht hu c nh cc hi dung mi, hi l cc ho than, hi t...Trong iu kin nhit cao cc cht hu c s b phn hu thnh than: kh v hi nc. Mun phn hy thnh than, kh v hi nc nhit phn hy i hi phi cao v tc phn hy thng chm. V vy ngi ta thng tin hnh phn hu nhit vi s ch mt ca cc cht xc tc.4.2.2. Thiu hy bng phng php ha hcy l phng php c s dng kh ph bin i vi cc kh c hi. Th d: SO2 (SO3) + NaOH Na2SO3 (Na2SO4)NOx + NH1OH NH1NOxi vi cc cht hu c c hi nh thuc tr dch hi, ngi ta thng s dng cc phn ng oxy ha kh hoc thy phn trong mi trng thch hp thay i cu trc phn t hay dng tn ti ca chng tr thnh cc sn phm t hoc khng c hi i vi ngi v ng thc vt.Th d* Phn vi zn c mt tia cc tmzn ha kt hp vi chiu tia cc tm l phng php rt c hiu qu i vi cht thi hu c hoc dung mi.Cht tr dch hi + O3UV CO2 + H2O + cc cht khng c* ha bng cc cht xy ha mnh khcCht hu c + KmnO4 Mn2+ + CO2 + H2O +... MnO2 + cc sn phm khng c4.2.3. Thiu hy bng phng php tt l phng php hay dc dng khi m sn phm khng th ti sinh hoc thu hi c. Qu trnh t thc cht l qu trnh tiu hu bng nhit nhng lun phi c mt khng kh. San phm ca qu trnh t ny thng l CO2., hi nc v cc kh khng hoc t c hi. Nhit i hi cho vic t kh v hi thi thng phi t800-1000oC. C 2 cch t:1. t khng c cht xc tcNhit ca qu trnh thiu t ny khng i hi qu cao phn hu hon ton cht v thng dng khi nng cc cht c hi cao (vt qu gii hn bc chy). V d nh t kh ng hnh trong khai thc du m.S ca mt qu trnh t khng xc tc nh sau:2. t c xc tc

Hnh 4. 1. S t khng xc tcTrong phng php ny ngi ta s dng cc kim loi c b mt rt pht trin nh bch kim, ng, niken lm cht xc tc. Nhit thiu t thp (t 50-300oC).Hnh 4.2: S ca qu trnh t c xc tcPhng php ny thch hp vi cc kh thi c hi c nng thp, gn vi gii hn bt la. So vi t khng xc tc th n r tin v sn phm thng an ton hn. Di y l m hnh ca mt s thit b x l kh bng phng php dt dng phun.

Hnh 4.3. t dng phun4.3. PHNG PHP NGNG TNguyn tc ca phng php l da trn s h thp nhit mi trng xung mt gi v nht nh th hu nh cc cht th hi s ngng t li v sau c thu hi hoc x l tiu hy. diu kin lm lnh bnh thng, nu x l bng ngng t thng khi thu hi c hi cc dung mi hu c, hi axt ra nhn phng pht ny ch ph hp vi nhng trng hp kh thi c nng hi tng i cao (>>20 g/m3). Trong trng hp nng nh, ngi ta thng dng cc phng php hp ph hayhp th. Hiu sut ngng t (gi tr tng i) c tnh theo cng thc:trong : CR: l nng hi u ra.Co: l nng hi ban du.Gi b tuyt i ca hiu sut ngng t tnh theo cng thc:trong :mi: l khi lng ca cht i c ngng tMi: l phn t lng ca cht VR: l lu lng kh u ra Vo: l lu lng kh u vo.Mt s cc thit b ngng t c dng nh m t di y (hnh 4.4a v 4.4b):

Hnh 4.4a. Thit b ngng t b mtHnh 4.4b. Thit b ngng t dng tip xc4.4. X L HI V KH THI BNG PHNG PHP HP PH4.4.1. khi qut v hin tng hp phHp ph l mt hin tng (qu trnh) gy ra s tng nng ca mt cht hoc mt hn hp cht trn b mt tip xc gia hai pha (rn - kh, rn - lng, lng - kh).Nh chng ta bit, cc phn t ca cng mt cht nm b mt v bn trong khi cht thng chu mc tng tc khc nhau dn n hnh vi ca chng cng khc nhau.Chng hn nh v trng lc, cc phn t bn trong khi cht chu lc tc dng mi pha ng u v nh nhau; cn cc phn t trn b mt th chu lc tc dng khng u nhau m lun lun c xu th b ko vo bn trong khi cht lm cho b mt khi cht c xu hng b co li to ra mt sc cng b mt (nng lng b mtt do) hnh thnh mt mt phn cch nh minh ha hnh trn. Ni chung cc phn t b mt ngn cch lun c nng lng t do cao hn cc phn t nm bn trong lng cht ca n.Khi b mt khi cht tip xc vi cc phn t ca cht khc, cc phn t trn b mt khi cht tc dng ln cc phn t ca pha khc nhng lc hng v pha mnh nhm cn bng v lc theo mi hng. y chnh l nguyn nhn ca s hp ph cht trn b mt cht khc.Cht gi cht khc trn b mt ca n th c gi l cht hp ph. Ngc li cht c gi li trn b mt ca mt cht no th gi l cht b hp ph.Trong trng hp tng tc gia b mt cht rn vi cc phn t kh hoc lng khi chng tip xc vi nhau m mnh, tng t nh tng tc trong mt phn ng ha hc, chng s to nn mt hp cht mi trn b mt tip xc - hp cht b mt. Nh vy thc cht c th chia hp ph lm hai loi: Hp ph vt l v hp ph ha hc.1. Hp ph vt lL loi hp ph gy ra do tng tc yu gia cc phn t; n ging nh tng tc trong hin tng ngng t. Lc tng tc l lc van der Waals. Trong nhiu qu trnh hp ph kh, s hp ph c th xy ra di tc ng ca cc lc phn t gy ra s vi phm cc nh lut kh l tng v hin tng ngng t. Dng hp ph ny cn gi l hp ph phn t hay hp ph van der Waals.2. Hp ph ha hcL loi hp ph gy ra do tng tc mnh gia cc phn t v to ra hp cht b mt gia b mt cht hp ph v cc phn t b hp ph. Hp ph ho hc c to ra do p lc ho hc. Thng thng nhit thp, tc hp ph ho hc cng chm. Khi tng nhit , tc hp ph ho hc tng nhng li lm gim qu trnh hp ph vt l. S hnh thnh cc hp cht b mt lin quan rt nhiu n hng ro hot ho c trng cho qu trnh tng tc gia cc phn t kh v cc nguyn t b mt cht rn. V vy hp ph ho hc cn c gi l hp ph hot ho (tuy nhin khng phi lc no cng vy). Nhit hp ph ca cht kh ln cht hp ph rn bao gi cng mang du dng, v vy p ng nhng yu cu v nhit ng hc th gi tr cn bng ca lng cht hp ph bao gi cng giam khi nhit tng.i vi cht b hp ph l cht kh, qu trnh ph thuc vo nhit v p sut. Lng kh b hp ph (thng gi tt l lng kh hp ph, k hiu bng ch a) l mthm ph thuc vo hai bin T v P.a = f(T,P)Nu gi nhit khng i ta c ng ng nhit:a = f (P) Nu gi p sut khng i ta c ng ng p:a = f (T)

Hnh 4.5.a. ng cong hp ph ng nhit v ng pT cc phng trnh hp ph v bng thc nghim, ngi ta tnh c rng nhit tng lm gim qu trnh hp ph. Ngc li p sut tng th li xc tin cho qu trnh hp ph xy ra mnh hn. Tm li h nhit hoc tng p sut s c li cho qu trnh hp ph.4.4.2. X l hi v kh thi bng phng php hp ph1. Nguyn l ca phng phpHi v kh c khi i qua lp cht hp ph b gi li nh hin tng hp ph. Nu ta chn c cc cht hp ph chn lc th c th loi b c cc cht c hi m khng nh hng n thnh phn cc kh khng c hi khc.Hnh 4.5.b: S thp hp ph s dng than hot tnhMt thit b hp ph v c bn c hnh dng nh trn hnh 4.5. Thng thng, c hai cch p dng phng php hp ph x l cht thi trong cng nghip.*Cch th nht l s dng thit b hp ph nh k, tc l trn mt thp hp ph, ngi ta nhi cht hp ph vo v cho cht b hp ph i qua . Sau mt thi gian nht nh cht hp ph " no" ( bo ho cht b hp ph) th qu trnh hp ph c dng li tho b cht hp ph "no" v a lng cht hp ph mi vo. Trong thc t, ngi ta thng dng bin php ti sinh li cht hp ph s dng li v thu cht b hp ph. Vic ti sinh thng c thc hin vi s c mt ca hi nc hoc kh nng.*Cch th hai l s dng thit b hp ph lin tc, trong cht hp ph c chuyn ng ngc dng vi cht b hp ph.2. Cc kiu tin hnh hp phTrong thc t tin hnh hp ph, ngi ta c th tin hnh theo hai phng php:phng php hp ph tnh v phng php hp ph ng.*Hp ph tnhKh nng hp ph ca mt cht hay dung lng hp ph ca mt cht ph thuc vo tnh cht, trng thi ho hc ca b mt, cu trc l xp ca cht hp ph cng nh ph thuc vo nhit v p sut ca qu trnh hp ph. Tu thuc vo c trng tng tc ca cht b hp ph vi b mt cht hp ph ta c hp ph vt l hoc hp ph ho hc.Trong trng hp chung, ta c phng trnh cho lng cht b hp ph nh sau:trong :a: l lng cht b hp ph trn mt n v khi lng cht hp ph (mol/gam). am: l lng cht b hp ph ng vi s lp y lp n phn t (mol/gam).h = P/Ps vi P l p sut ring phn ca kh b hp ph, Ps l p sut hi bo hoca n.k: l h s biu hin s tng tc ca cht hp ph v cht b hp ph.i vi mt cht hp ph thng thng c b mt phng, s ngng t mt cht ch xy ra khi h > 1.Tuy nhin, trong cc cht hp ph xp (ng knh l xp khong 10-15 Ao) th xut hin s ngng t mao qun. trong cc vng mao qun ca cht hp ph c th xy ra qu trnh hp ph ngha l cc cht kh hoc hi b gi li (c ngng t) mc d p sut hi ring phn nh hn p sut hi bo ho (khi t l P/Ps nh hn1). Hin tng ny xy ra l do ti y tn ti mt trng lc hp dn c bit c th ngng t cht b hp ph ngay c khi nng (p sut ring phn) ca chng rt b, to iu kin thu gi rt tt cc cht, nht l cc cht hu c, to nn ct cht lng trong cc l xp ca cht hp ph.*Hp ph ngThc t ca qu trnh lm sch kh thi bng phng php hp ph l mt qu trnh ng. Qu trnh hp ph thng thng c tin hnh trong cc bung hp ph c cha cc cht c kh nng hp ph. Kh thi cha cc cht cn hp ph c dn qua lp cht hp ph. Cc cht cn hp ph s c gi li cn kh sch s c thi ra ngoi.Nu cht hp ph c hot cn bng l a, chiu dy ca lp hp ph l L, din tch thit din ngang ca thit b hp ph l S, kh thi c nng cht cn hp ph lCo v tc dng trong thit b hp ph l w th lng cht c hp ph s c tnh theo biu thc:M = a. S. Lhay mt = w. S. Co. (a C)trong : l thi gian dng kh tip xc vi lp cht hp ph c lng cht c hp ph l mt ti thi im t.

Ta gi thit: tc hp ph l v cng ln v cht nhim bn ngay lp tc t ti cn bng khi tip xc vi cht hp ph.T ta rt ra:iu c ngha l ng vi mt loi cht hp ph (thit b hp ph tng ng) no c chiu dy lp cht hp ph L, nng dng kh a vo thit b Co vi tc w th sau thi gian T bt u xut hin s lt cht bn ra khi thit b hp ph. iu cng c ngha l vic s dng cht hp ph cn c ti sinh nh k.ng biu din qu trnh hp ph trong thp s c dng nh trong hnh 4.6.Hnh 4.6. ng cong hp ph trn thpPhng php hp ph ng c hiu sut cao hn v ph hp hn i vi thc tin sn xut nn thng c s dng trong x l kh thi cng nghip. Mt s loi thit b hp ph c m t trong hnh 4.7.Hnh 4.7a. Thit b hp ph dng quayHnh 4. 7b. Thit b hp ph dng khay hn hpMt h thng thit b x l kh thi bng phng php hp ph thng c dng nh sau:Hnh 4.8: S h thng thit b x l kh thi bng than hot tnh4.3. Cc cht hp ph s dng trong cng ngh x l kh thiNh vy, ty thuc vo bn cht ca cht hp ph v cht b hp ph; tu thuc vo nng lng tng tc gia cht hp ph v cht b hp ph m ta c th la chn c cht hp ph c dung lng ln v kh nng hp ph chn lc i vi mt cht bn no . Mt khc cht hp ph cn phi l nhng h c b mt ring rt pht trin to ra mt tng tc ln vi cht b hp ph. iu cho php trong tng trng hp c th c th chn la c cht hp ph c chn lc cao, m bo lc sch kh vi s tiu tn t.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, sihcagen, zeolit c hot cao v kh d dng ti sinh.1. Than hot tnhThan hot tnh l mt cht hp ph rn, xp, khng phn cc v c b mt ring rt ln. V bn cht nguyn t, n thuc nhm graphit - mt dng th hnh ca cacbon- gm cc tinh th nh c cu trc bt trt t; nhng khc vi graphit l trong tinh th ca than hot tnh cc vng su nguyn t cacbon sp xp km trt t hn. V vy than hot tnh c cu to xp hn v to nn nhiu l hng nh khng ng u v rt phctp.Cu trc l xp phc tp v b mt ring khc nhau lm cho cc loi than hot tnh ny tr nn c kh nng hp ph khc nhau. Vic to ra cc loi than khc nhau ph thuc ch yu vo cch ch to.Nhn chung, cc l xp trong than hot tnh c bn knh hiu dng t vi chc n hng chc nghn anstron. V mt cu to, n c cu to kiu t ong gm mt h l xp mao qun thng nhau v thng vi mi trng bn ngoi vi cu trc khng gian ba chiu. C th chia kch thc l xp thnh ba loi sau:* Dng vi mao qun, bn knh hiu dng c 10 Ao, c b mt ring ln nht (3501000 m2/gam v chim phn ch yu trong than hot tnh.*Dng mao qun trung gian c bn knh hiu dng trong khong 100 n 250 Ao, b mt ring khng ln lm, khong 100 m2/gam.*Dng mao qun ln c bn knh hiu dng khong 1.000 n 10.000 Ao; dng ny c b mt ring rt nh, khng qu 2 m2/gam.Than hot tnh c tc dng hp ph tt i vi cc cht khng phn cc dng kh v dng lng. T lu than hot tnh c s dng lm mt n phng c, lm sch mi v kh mu cc sn phm du m. Ngy nay trn th gii than hot tnh c coi nh l mt cht hp ph ch yu trong cng ngh x l lm sch mi trng bao gm cc lnh vc:- Lm sch nc ung, x l nc sinh hot hoc x l nc thi ca cc cng trnh c nhim bn thp. Trong nhng trng hp ny, than hot tnh s gi li cc hp cht hu c ho tan, nht l cc cht gy mi, gy mu v c vt nhng kim loi nng. Than hot tnh c bit c hiu qu x l cao i vi nc b nhim nh cc cht dit tr dch hi.- X l nc thi cng nghip. Ngi ta s dng than hot tnh trong nhng trng hp hp ph cc cht km hoc khng b vi sinh vt phn hy, cc cht gy c hi i vi cc vi sinh vt. Trong trng hp ny x l chn lc bng than hot tnh ng vai tr nh l qu trnh tin x l cho cc bc x l sinh hc tip theo.- X l "cp ba" nc thi cng nghip v th.Khi than hp ph "no" (bo ha), n khng cn kh nng hp ph tip tc na. i vi than hot tnh, trong trng hp ny khng phi b i m c th ti sinh v s dng li c. i a s cc cht hp ph trn than hot tnh u c th gii hp bngnhit. Khi trong mi trng c nhit cao, cc cht hu c cng nh cc phn t axit d bay hi tch khi b mt ca than. i vi mi mt cht s c mt nhit x l ph hp. Vi cc hp cht ca kim loi th thng thng phi gii hp bng axit sau ra bng nc v sy ti sinh.2. SilicagelSilicagel l gel ca anhydrit axit silisic c cu trc l xp rt pht trin. Mng li ca gel bao gm cc nguyn t Si nm gia khi t din ni vi nhau thng qua cc nguyn t O phn b ti cc nh. B mt ca gel thay v cc nguyn t oxy l cc nhm hydroxyl (OH); iu quyt nh tnh cht hp ph ca silicagel.Silicagel d dng hp ph cc cht phn cc cng nh cc cht c th to vi nhm hydroxyl cc lin kt kiu cu hydro. i vi cc cht khng phn cc, s hp ph trn silicagel ch yu do tc dng ca lc mao dn trong cc l xp nh.Cng nh cc cht hp ph c th ti sinh khc, ch ti sinh silicagel c mt ngha rt quan trng. i vi silicagel, trng thi ha hc ca b mt gel quyt nh tnh hp ph mnh cc cht phn cc. Trng thi ny ch c bo ton nhit di 200oC, nu gii hp c tin hnh bng kh kh. Nu ti sinh silicagel nhit cao hn s dn n s thay i bt thun nghch ca cu trc v b mt lm mt kh nng hot ng ca silicagel. Do cu to ca silicagel, c bit l s c mt ca nhmOH, nu tin hnh gii hp bng kh nng m hay bng hi nc vi thi gian ko di s lm gim hot tnh hp ph ca chng m nguyn nhn ch yu l do b gim b mt ring. V vy vic gii hp i vi silicagel cn phi lu hn so vi vic gii hp than hot tnh.3. ZeolitZeolit l cc hp cht alumosihcat c cu trc tinh th. So vi silicagel, trong mng li tinh th ca zeolit mt phn ln ion Si4+ c thay th bng cc ion Al3+ dn n s thiu ht v in tch dng. V vy zeolit c th tip nhn cc cation nht nh ca cc kim loi khc. Mt khc s thiu ht ny ph v cu trc u n ca tinh th n cht, gy ra nhng khong khng gian trng v cc lc in trng khc nhau trong zeolit.Tnh cht ca zeolit ph thuc vo t l Si v Al v mc to tinh th ca sn phm cui cng; ng thi n cn chu nh hng ca cc cation kim loi khc c nhn thm vo trong qu trnh hnh thnh sn phm.V vy ngi ta c th to ra nhng kiu zeolit khc nhau bng cch iu ch chng vi cc t l khc nhau ca Si v Al. c bit tng hot tnh hp ph v xc tc, zeolit t nhin hoc zeolit sau khi tng hp c thng c bin tnh bng cc cation kim loi c hot tnh xc tc, hp ph. Trong cng nghip ph bin nht l cc zeolit A v zeolit X. Cc zeolit ny c tnh hp ph kh tt v tng i chn lc.

Hnh 4.9. Cu to ca zeolitCc zeolit th hin tnh nhy cm rt r i vi nhit . Th d nh zeolit cha Ca ch b mt tnh hp ph khi nhit ln ti 800oC, cha Na b mt hot nhit 700oC cn zeolit cha Li th 640oC.S dng zeolit lm cht hp ph hay c p dng trong k ngh. V d nh cc hp cht mercaptan hu nh c loi b hon ton khi s dng zeolit NaX nhit thng (dung lng hp ph etylmercaptan 25oC l 0,19 kg/kg) hoc nh ngi ta c th s dng zeolit A x l nc bin.4. Cc cht hp ph khcTrong t nhin c nhiu loi khong cht c kh nng hp ph nh st, bentomt, diatomit... Cc loi khong cht ny thng c lm tng kh nng hp ph ca chng ln nhiu sau khi x l bng cc bin php ph hp. Tnh u vit nht ca cc cht hp ph t nhin l chng c gi thnh rt thp so vi cc cht hp ph nhn to.Cc mui v c v cc oxit kim loi cng c th c dng lm cht hp ph khi ta a n ln trn mt cht mang no , chng hn nh silicagen, oxit nhm... lm iu , ngi ta trn u dung dch 20-25% ca mui yu cu vi cht mang ri sy kh.4.4.4. Nhng u v nhc im ca phng php x l bng hp phPhng php hp ph c kh nng lm sch cao. Cht hp ph sau khi s dng u c kh nng ti sinh; iu ny lm h gi thnh x l v y cng l u im ln nht ca phng php.Nhc im ca phng php l khng th s dng i vi ngun thi c ti trng nhim cao. Qu trnh x l thng phi thc hin theo phng php gin on.Chnh v nhng u, nhc im trn cho nn khi c nh s dng phng php hp ph cn phi cn nhc v phn tch, iu tra t m v tht c th ri mi tin hnh.4.5. X L KH THI BNG PHNG PHP HP TH4.5.1. Nguyn lC s ca phng php l da trn s tng tc gia cht cn hp th (thng l kh hoc hi) vi cht hp th (thng l cht lng) hoc da vo kh nng ha tankhc nhau ca cc cht khc trong cht lng tch cht.Tu thuc vo bn cht ca s tng tc ni trn m ngi ta chia thnh s hp th vt l hay s hp th ha hc.1. Hp th vt lL 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. ha tan ca mt cht cn hp th trong lng cht lng lun lun l mt hm ca nhiu bin s. Nu gi D l tan th ta c th biu din n nh sau.D = f (x1, x2.... xj. T, S, P, kD)trong :x: l nng ca cc cht kh hoc hi trong cht lng. T: l nhit lm vic.S: l din tch tip xc gia hai pha.P: l p sut ring phn ca hi hoc kh trong pha kh.kD: l h s khuch tn ca cht c hp th trong pha lng. Ta c th biu din qu trnh hp th qua s sau:Trong trng hp xj 0P 0Phng trnh Henryta c phng trnh Henry

Pi = D.xj (vi S=1)H s tan D ph thuc vo nhit theo phng trnh:trong : H l nhit ha tan ca kh; A l hng s; R l hng s kh = 8,31 kj/kmol..Thc t qu trnh hp th trn l qu trnh ng, trn b mt tip xc gia cc pha lun lun c qu trnh cn bng xy ta v s chuyn dch cn bng. Do vy i hi phi quan tm n qu trnh chuyn pha (t pha kh sang pha lng, cc phn ng xy ra khi c tip xc pha, qu trnh chuyn cht vo su trong lng cht lng cng nh cc nh hng ca nhiu yu t n cn bng vt cht trn ranh gii phn cch pha).V th, qu trnh hp th s tng khi din tch tip xc hai pha tng v nhit lm vic gim; ring hiu sut x l th cn ph thuc nhiu vo p sut ring phn ca kh hoc hi v nng ca chng trong pha lng. tng hiu qu x l, ngi ta thng dng cc kiu thit b lm tng din tch tip xc ti a, truyn nhit tt v hn ch s tng ca cht in ly trong pha lng (i vi trng hp cht b hp th l kh). C cc kiu thit b thng dng nh: thp hp th c tng m, thp hp th si bt, thp phun...2. Hp th ha hcHp 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. Nh vy s hp th ha hc khng nhng ph thuc vo tc khuch tn ca cht kh vo trong cht lng m cn ph thuc vo tc chuyn ha cc cht - tc phn ng ca cc cht.Trong hp th ha hc, cht c hp th c th phn ng ngay vi cc phn tca chnh cht hp th. Th d: amoniac hay kh sunphur hp th vo nc:NH3 + H2O NH4OH NH +

+ OH-SO2 + H2O H2SO3 H+ + HSO3-Cht c hp th phn ng vi cc thnh phn hot ng trong cht hp th (thng thng l dung dch ca cc cht hot ng). Th d nh hp th CO2, SO2 trong dung dch NaOH:

CO2 + 2NaOH Na2CO3 + H2O

Na2CO3 + H2O + CO2 2NaHCO3

Vi SO2 cng c phn ng tng t.Trong trng hp chng ta c th biu din phng trnh phn ng mt cch tng qut nh sau:Khi t ti cn bng, hng s cn bng, phn ng c dngng.

Kcb cng ln bao nhiu th qu trnh hp th xy ra cng thun li by nhiu.Gi tr [A] l nng t do ca cht A trong dung dch cha tham gia vo phn4.5.2. S chuyn cht trong qu trnh hp thKhi cha t ti cn bng gia cc pha (chng hn pha hp th l lng v pha bhp th l kh) th xy ra s chuyn cht t pha ny sang pha khc - qu trnh ny gi l s chuyn khi.Tng t nh s truyn nhit, s chuyn khi l mt qu trnh phc tp, bao gm cc qu trnh chuyn cht ti ranh gii gia cc pha. Khi xt qu trnh ny, ngi tada vo mt s gi thuyt m ta khng xt ti ti y. n gin, ngi ta da vo phng trnh chuyn khi:WA = .F.trong : WA l lng cht chuyn c trong mt n v thi gian; F l b mttip xc; l lc chuyn ng-biu din cho s khc nhau v nng dung dch tithi gian hp th vi nng thi im cn bng; l h s t l (h s chuynkhi)-lng cht chuyn vo bn trong pha trong mt n v thi gian qua mt n v b mt khi chuyn ng bng l, chu nh hng ca mt , nht, h s khuch tn, nhit , p sut nng ca, cht trong cht hp th v sc nng b mt.Tuy nhin, tu trng hp c th, ngi ta phi xem xt xem c ch chuyn cht s l khuch tn phn t hay khuch tn ri l chnh a ra cc m hnh chuyncht4.5.3. Cc loi thit b hp th1. Thit b hp th kiu mng cht lngMng cht lng trong thit b hnh thp c to thnh khi cho cht lng chy thnh mng theo cc ng, tm tnh hay a quay b tr hp l trong thp. Cht lng theo mng c th chuyn ng t trn xung di v kh i t di ln trn; rt t khi s dng ch chuyn ng cng chiu t di ln trn ch lm vic ny ch s dng khi tc ca dng kh thi cao - trn 15 - 20 m/s). Vi thit b mng ng v mng tm, ngi ta thng p dng cho kh thi c tc trung bnh t 4 n 5 m/s. Thit b hp th kiu mng cht lng c u im l to c din tch tip xc pha kh ln v c kh nng tch, thot nhit tt ng thi vi qu trnh hp th.Ngy nay ngi ta t dng cc thit b hp th kiu mng ng v mng tm. Duy cn ph bin hn c l trong trng hp hp th mt s kh ho tan tt, c nng cao t hn hp kh m c ng thi c s to nhit mnh nh HCl, NH32. Thit b mng a quayC cu to ging nh thit b a quay trong x l bi v sol. Cht lng hp th c phn b u trn cc tng a, chuyn ng t trn xung v c quay trn lin tc trong sut qu trnh x l. Thc nghim cho thy tc chuyn khi tng khi tng s vng quay ca a. Trong thit b mng quay, sc cn thy lc nh v c th lm vic vi mc tiu hao cht hp th thp.Trong cng nghip, thit b ny vn c s dng th d nh hp th HCl hay SO2 bng Na2S trong sn xut natrithiosunphat (Na2S2O3). Thit b c 11 vi ng knh 800 mm, tc quay l 150 vng/pht, lm vic c vi nng sut l 1.700m3/h.3. Thp hp th loi mc dng ph bin nht. Trong thp, ngi ta thng nhi cc vt th lng cng nh c, snh s, l so kim loi. vn than cc... lm tng din tch tip xc haipha. Khi vn hnh, kh thi c i t di ln trn cn cht lng th i t trn xung di. Lu lng ca hai pha lun c tnh ton trc thit b t hiu qu cao nht. Khi cht lng chy trn b mt cc vt th m, v c bn chng c c trng ca mng cht lng. Tuy nhin v bn cht ca qu trnh vn hnh, gia thit b hp th mng v thit b hp th m c s khc nhau. thit b hp th mng, mng cht lng chuyn ng lin tc theo chiu cao ca thp hp th; cn trong thit b hp th m th khi nng cht lng chuyn ng t n nguyn ca vt m ny sang n nguyn ca vt m khc th mng c b ph v v mng mi c hnh thnh. Qu trnh ny c lp i lp li trong sut chiu di ca thp. Vic ph v l do s chuyn ng ngc chiu ca dng kh. Do vy m thp m phn no cn mang tnh cht nh mt thp hp th si bt.S chuyn ng thun dng trong thp m i khi cng c s dng. l nhng trng hp khi tc kh thi kh ln (khong 10 m/s), khng hoc kh thc hin c i vi kiu ngc dng. S b tr thun dng s lm tng qu trnh trao i cht, gim tr lc thy ng v gim kch thc ca thit b.Trong trng hp s hp th i km vi cc phn ng thy phn hoc to kt ta th ngi ta thng dng loi thp hp th m ni. Cc lp m ni (nhng mnh bt xp polyme hay cc qu cu rng lm bng cht do) c "treo" l lng bi dng kh trong thp v bi cc tm li . Gia cc lp m l nhng khong trng m bo cho cc kt ta khng lm tc nghn s lu thng ca dng kh qua cc lp m. Tt nhin y cht hp th lng cng c chuyn ng t trn i xung.Cc nghin cu thy ng hc v chuyn khi trong cc thit b hp th m ni cho thy, thp hp th kiu ny c th lm vic vi tc dng kh ln m khng b tc nghn. Nhc im ca thp hp th m ni l kh thot nhit trong qu trnh hp th. Mun tch nhit, ngi ta thng phi s dng lm lnh tun hon.Trong cng nghip sn xut axit phophoric t qung ngi ta s dng kiu thp hp th m ni hp th kh SiF4 hay SiCl4 vo nc v chng to thnh axit silisic khng tan trong nc hay dng huyn ph vi hp th cc kh nh CO2, SO24. Thp hp th si bt (ging nh thp si bt trong x l bi)Thng c s dng trong trng hp ti lng cao, p sut kh phi ln v qu trnh hp th c s to nhit, cn c lm lnh.Cc kiu thp hp th si bt chnh gm (l) si bt qua li (hay vt xp), (2) si bt qua cc a chp xen k v (3) trn c hc kh v cht lng.Hp th kiu si bt c nhc im ln nht l lun c lp bt chim th tch kh ln trong thit b. Vic chuyn ng ca cht lng gp phi tr lc ln. Cc nh thit k c nhiu cng trnh lm gim bt nhng nhc im trn c th s dng kiu hp th ny trong cng nghip v n c h s chuyn khi rt cao.Chiu cao lp cht lng tng s lm tng kh nng hp th song ng thi cng tng tr lc ca thit b. V vy, thng thng ngi ta khng tng lp cht lng qu50 mm.5. Thp hp th kiu a chpThp hp th kiu a chp to ra s chuyn ng i dng ca dng hi, kh thi v cht lng hp th qua tng bc mt. Cht lng i t pha trn a xung, ri vo y ca a pha di ri tip tc chy xung pha trn ca a tip theo. Cn kh th len li cng theo con ng y nhng ngc chiu vi cht lng.6. Thp phunL loi thit b hp th n gin. Trong thp phun, cht lng c phun thnh bi m (sng) t pha trn xung, kh thng i t di ln nhm lm tng din tch tip xc v nng thc t ca cht cn hp th trong pha kh gim dn theo chiu t di i ln v nng cht b hp th trong pha lng c tng dn theo chiu t trn i xung. Qu trnh ny rt c li cho vic tng hiu qu x l.Thp hp th phun c th chia ra lm ba kiu khc nhau: (1) thit b hp th phun kiu thng rng, (2) thit b hp th phun thun dng tc cao v (3) thit b hp th phun sng kiu c kh.* i vi kiu thng rngThit b hp th kiu thng rng 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.Thit b hp th thng rng c u im l n gin, u t thp, lc cn thy ng nh v c th s dng i vi kh thi c nhim bn cao; cht lng dng hp th c th quay vng cho ti khi hp th no mi thi cho nn tit kim c cht hp th.Nhc im ca thit b thng rng l kh thng phn b khng u trong ton b thp dn dn lm gim hiu sut x l. Tuy nhin kh phn b u ngi ta to ra cc b phn phn phi kh nh phn phi kh qua ming tht, phn phi kh thng qua mng phn phi xp hay phn phi kh theo dng xoy kiu cyclon...Thm na, o loi thit b kiu ny hiu qu x l khng cao v h s chuyn khi thp, nn tc dng kh khng c qu ln (phi nh hn 1 m/s) trnh hin tng cht lng b cun theo kh ra ngoi.* Thit b phun thun dng tc caoThit b kiu ny ph hp vi dng kh thi c vn tc ln (khong t 20 - 30 m/s). Cho nn, khi vn hnh cht lng thng b cun theo cng dng kh, sau c tch ra bi mt thit b km theo. Thit b phun thun dng tc cao c dng nh kiu thit b Venturi (ging nh trong x l bi). Kh thi vi tc cao i qua ng tht, cun theo cht lng t ca ch di dng bi sng v cng i vo vng khuch tn ri ti b phn tch cht lng. Trong vng khuch tn, ng nng ca dng kh chuyn thnh p lc vi mc hao ht l cc tiu. Thit b phun thun dng tc caoc s dng kh ph bin trong x l kh thi.* Thit b phun sng kiu c kht c s dng, n ch ph hp trong nhng trng hp c bit. Tm li, cc loi thit b dng trong hp th rt hay c s dng trong cng nghip bi kh nng loi b ng thi c bi v kh cng nh kh nng lm sch trit bi ca n. Tuy nhin, tu trng hp c th, tu lu lng, nng v cng bi kh thi m chng ta s tm chn phng php ph hp.4.5.4. Mt s v d hp th trong cng nghip1. Hp th bng duNgi ta thng s dng cc loi du hp th cc hp cht hyrocacbon. Chng hn nh vic hp th butadien: hp th, ngi ta dng ru etylic, du ho... ho tan ca butadien tun theo quy lut Henry, c dng nh phng trnh thcnghim di y:trong : x l phn mol butadien trong dung dchT l nhit .2. Hp th bng axetylen hp th cc hp cht nh dimetylformamit ((CH3)2CONH), metanol (CH3OH), amoniac lng (NH4OH)..., ngi ta c th dng axetylen. Ch rng axetylen nhit thng l kh, do vy thc hin c hiu qu s hp th (metanol, amomiac lng) ngi ta tin hnh hp th chng iu kin nhit thp (-10 -78 oC).3. S hp th CO2Ngi ta s dng nc, metanol, kim, dung dch amoniac hp th CO2* Trong metanol, CO2 hp th theo kiu vt l.* Trong nc, sau khi khuch tn vo, CO2 s hp vi nc to thnh cc sn phm H2CO3 v HCO3-. Nhng sn phm ny trong nc hnh thnh cn bng thun nghch sau:Nhit tng s thc y qu trnh gii hp. Do vy hp th CO2 tt nht l tin hnh nhit thp.* Khi s dng dung dch kim hay amoniac th ng thi vi qu trnh hp thha tan l cc phn ng trung ha to thnh cc mui tng ngCO2 + 2NaOH = Na2CO3 + H2O CO2 + Na2CO3 + H2O = 2NaHCO34. S hp th SO2C th s dng nc, soda hoc dung dch amoni sunfit hp th SO2*Khi hp th bng nc, trong dung dch tn ti cn bng sau:* Khi hp th bng xt, ta c cc phn ng:2NaOH + SO2 Na2SO3 + H2O Na2SO3 + SO2 + H2O 2NaHSO3* Khi hp th bng dung dch amoniac, to nn (NH4)2SO3 v NH4HSO3. Songtrn b mt dung dch hp th c phn ng thun nghch:5. Hp th cc hp cht hu c cha lu hunhTa c th s dng bin php hp th ho hc loi b cc hp cht hu c c cha lu hunh c trong dng kh bi thi. Vic hp th ny da trn kh nng to ra lin kt ho hc gia cc hp cht cha lu hunh vi mt tc nhn hot ng mnh nh cc oxyt km, si, ng nhit khong 200- 400oC.S nguyn tc gm hai giai on: t nng kh v phn ng hp th. Cc phng trnh hp th xy ra nh sau2ZnO + CS2 = 2ZnS + CO2-ZnO + COS = ZnS + CO2ZnO + C2H5SH = ZnS + C2H4 + H2O ZnO + C2H5SH = ZnS + C2H5OHPhn ng gii hp th xy ra nhit 500-550oC bng cch oxy ha ZnS bngoxy khng kh. y l mt phn ng to nhit nn vic lm qu nng ZnO s dn ti gim hot hp th ca n. V vy, trong thc t, ti sinh ZnO ngi ta dn dng hn hp khng kh c nng oxy khong 0,5 % vo cng vi kh tr.Cn nh rng, trong phng php hp th ho hc, vic chn cht hp th ng vai tr quan trng song song vi s la chn thit b hp th.Di y chng ti xin gii thiu mt s h thng thit b thng dng trong x l bi v kh thi:Hnh 4.10. S t hp lc bi trong cng nghipHnh 4. 11. Tun hon cht lng raHnh 4.12. H thng x l biHnh 4.13. H thng tun hon nc raPhn IICNG NGH X L NC THIChng 5MT S VN C BNLIN QUAN N X L NC THI5.1. NHNG NH HNG CA NHIM NC GY RA I VI NGUN NC TIP NHNS nhim bn ngun nc c th xy ra theo hai cch: Nhim bn t nhin v nhim bn nhn to.- Nhim bn t nhin do nc ma chy trn trn b mt t mang theo cht bn v vi khun gy bnh vo ngun nc tip nhn.- Nhim bn nhn to ch yu o x nc thi (sinh hot, bnh vin, cng nghip v nng nghip) vo ngun nc tip nhn.Sau y l mt s nh hng chnh do nc thi gy ra i vi ngun nc tip nhn:+ Xut hin cc cht ni trn mt nc hoc c cn lng: Cc hin tng nhim bn ny thng do nc thi t cc x nghip ch bin thc phm hoc nc thi sn xut ca cc x nghip c cha du m v cc sn phm m. Chng to nn lp mng du, m ni trn mt nc v nu cn nng th lng xung y. Chng lm cho nc c mi v c trng v lm gim lng oxy trong nc ngun. Vi hm lng du 0,2- 0,4 mg/l s lm cho nc c mi du. Kh mi du l mt vic lm kh khn. Tm c sng trong nc b nhim bn do cc sn phm du m c tc sinh trng rt km, thm ch khng sinh trng c v tht ca chng c mi du.+ Thay i tnh cht l hc: Ngun nc tip nhn nc thi s b c, c mu, c mi do cc cht thi a vo hoc do s pht trin ca rong, ru, to, sinh vt ph du... to nn.+ Thay i thnh phn ho hc: Tnh cht ho hc ca ngun nc tip nhn s b thay i ph thuc vo loi nc thi ra. Hin tng ny to ra l do nc thi mang tnh axit hoc kim hoc cha loi ho cht lm thay i thnh phn v hm lng cc cht c sn trong thy vc.+ Lng oxy ha tan trong nc b gim: Hm lng oxy ho tan trong ngun nc tip nhn b gim l do tiu hao oxy oxy ho cc cht hu c do nc thi vo. Hin tng gim hm lng oxy ho tan (< 4 mg/l) trong nc gy nh hng xu cho cc loi thy sinh vt.+ Xut hin hoc lm tng cc loi vi khun gy bnh: Nc thi ko theo ccloi vi khun gy bnh vo ngun nc tip nhn lm suy gim cht lng i vi vic cung cp nc cho cc mc ch trong c bit l mc ch sinh hot.Tm li, nc thi nu b lu ng hoc x l cha t yu cu s gy nhim mi trng, c bit i vi ngun nc tip nhn, hu qu ko theo gy tc ng xu n v sinh mi trng v sc kho con ngi.5.2. CC IU KIN V CC PHNG N CNG NGH X L NC THIH thng x l nc thi thng bao gm tng hp cc phng php l hc (chc), ho hc v sinh hc.Vic p dng cc phng php trn ngoi s ph thuc vo tnh cht nc thi (bng 5.1), lu lng nc thi cn ph thuc vo hng lot cc yu t khc nh: kinh ph, din tch dnh cho h thng x l, c im a hnh, h thng thot nc, mc ch s dng ca ngun nc tip nhn v.v...Bng 5.1. Cc phng php x l nc thiCht bnCc phng php x l

Cht hu c d phn hy sinh ho (BOD)Cht l lngCht hu c bn vngNhPhotphoKim loi nngCht hu c tan- Phng php sinh hc hiu kh (bn hot tnh, h lm thong, lc sinh hc, h n nh).- Phng php sinh hc trong iu kin ym kh (h ym kh, b mtan) bm xung lng t UASB.- Lng, tuyn ni v li lc, song chn.- Hp ph bng than, bm xung lng t.- H, sc kh, nitrat ho, kh nitrat, trao i ion.- Kt ta bng vi, bng mui st, nhm.- Kt ta kt hp sinh hc, trao i ion.- Trao i ion, kt ta ho hc.- Trao i ion, bn thm, in thm.

C th chia lm 3 bc x l nc thi: Bc 1, bc 2 v bc 3.+ X l bc 1 cn gi l x l s b thng thng l cc cng trnh x l l hc (c hc) nh: Song chn rc, b lng. Cc cng trnh nhm mc ch tch cc cht khng tan trong nc thi. X l bc 1 nhiu khi mang mc ch x l c cht nhim, to iu kin ph hp a tip vo h thng x l tip theo. V d: X l du m, trung ho nc thi... to iu kin cho bin php x l sinh hc tip theo. Trong nhng trng hp ny x l bc 1 c th l cc bin php l - ho.Bng 5.2. X l nc thi bc 1Cht bnPhng php x l

Cht l lng Du hoc m Kim loi nng Kim v axit Sun phuaS bin ng v nng cht bn (BOD) v lu lngH: lng, tuyn niThu du m. thu vt bt Kt ta hoc trao i ion Trung hoKt ta hoc sc khiu ho nng , lu lng

+ X l bc 2: Thng thng x l bc 2 l cc cng trnh x l sinh hc dng oxy ho sinh ho cc cht hu c cn li dng tan, keo v khng tan (nhng khng lng c).+ X l bc 3 thng c thc hin theo yu cu x l c cht lng cao hn. l cc trng hp cn thit phi p dng cc bin php nh trit khun, kh tip cc cht bn cn li trong nc thi nh nitrat, photphat, sunphat....Chng 6CC PHNG PHP X L NC CP6.1. KH ST BNG PHNG PHP LM THONGNguyn tcOxy ho st ho t 2 (Fe2+) ho tan thnh st ho tr 3 (Fe3+). St ho tr 3 tip tc thu phn to thnh hydroxt kt ta Fe(OH)3. Cui cng cc cn Fe(OH)3 c tch ra khi nc bng lng v lc. thc hin phng php ny nc ngm c lm thong (phun thnh cc ht nh) tng din tch tip xc vi khng kh, nh vy nc hp ph O2 c trong khng kh v mt phn CO2 ho tan trong nc s tch ra khi nc.Phn ng oxy ho thy phn st c th biu din bng phng trnh sau:4Fe(HCO3)2 + O2 + 2H2O = 4Fe(OH)3 + 8CO2 phn ng oxy ho v thu phn st xy ra nhanh v trit , nc phi c kim thch hp v pH nm trong phm vi 7 - 7,5.6.2. TRIT KHUNSau khi qua b lng, b lc, phn ln vi khun trong nc b gi li (90%) v b tiu dit. Tuy nhin, m bo hon ton v sinh, phi p dng phng php tritkhun nc.Phng php trit khun nc thng dng nht l Clo ho tc l s dng Clo hoc hp cht ca Clo nh clorua vi (CaOCl2), zaven (NaOCl) l nhng cht xy ha mnh, c kh nng trit khun.Khi a clorua vi vo nc s xy ra phn ng:Khi a Clo vo nc s din ra phn ng:Cl2, HOCl, OCl- u l nhng cht oxy ho mnh. pha ch v nh lng clorua vi ngi ta dng nhng thit b nh khi pha ch phn, Clo c sn xut ti nh my ho cht di dng lng v c a vo nc di dng hi nh mt loi thit b ring gi l Clorator.Clo hay clorua vi c a vo nc trong ng ng t b lc sang b cha vi liu lng 0,5-1 mg/l. Ngoi Clo hin nay cn dng phng php in phn mui NaCl ti ch, sn xut Zaven (NaOCl) st trng.Vic s dng Clo ho dit cc vi khun cn c kim sot cht ch v nu nc cha cn cha nhiu cc cht hu c s to iu kin hnh thnh CHCl, v cccht hu c Clo khc (v d: clo-amin nu nh cc amoni c trong nc) gy c i vi sc kho con ngi. T chc EPA (Hi bo v mi trng M) cho php nng CHCl3 c trong nc n ung l 100 ppb (mg/l).(-CH-CH2-CH2-CH2-) + Cl2 CHCl3 + (C, H, Cl)Cc cht hu c tan Cc cht hu c c o haiu ny c th c ngn chn nu nh nc Clo ha c x l tip bng than hot tnh.Ngoi cc phng php o ho, trn th gii nhiu nc cn s dng cc phng php sau:+ Dng tia t ngoi: Dng mt loi n pht ra tia t ngoi trit khun. Phng php ny n gin nhng thit b t hay hng v tn in (10-30 kW/1000 m3 nc).+ Dng zn (O3): Khi a O3 vo nc s to thnh oxy nguyn t l cht c kh nng dit trng.+ Dng sng siu m: Dng thit b pht ra sng siu m tn s 500 kHz vi trng s b tiu dit.Chng 7CC PHNG PHP X L NC THI7.1. PHNG PHP X L C HCPhng php ny thng l giai on x l bc 1 (giai on x l s b), t khi l giai on kt thc qu trnh x l nc thi dng loi cc tp cht khng tan trong nc. Cc cht ny c th dng v c hay hu c.Cc phng php c hc thng dng l: lc qua li, lng, cyclon thu lc, lc qua lp ct v quay ly tm.7.1.1. Phng php lngNhng cht l lng (huyn ph) l nhng cht c kch thc ht ln hn 10-1 mm. Nhng cht l lng trong nc thi gm nhng ht hoc tp hp ht khc nhau v hnh dng, kch thc, trng lng ring v bn cht xut x. Tnh cht c bn ca cc cht dng huyn ph l lng l khng c kh nng gi nguyn ti ch trng thi l lng. Thi gian tn ti ca chng ty thuc vo kch thc ht. Cc ht ln s lng hoc ni ln mt nc di tc dng ca trng lc.7.1.2. Phng php lcLc l qu trnh tch cc ht rn ra khi pha lng hoc pha kh bng cch cho dng kh hoc lng c cha ht cht rn chy qua lp vt ngn xp. Cc ht rn s b gi li trn b mt lp vt ngn cn kh hoc cht lng s thm qua vt ngn.7.1.3. B iu hoThng thng, lu lng, nhit , hm lng cc cht nhim v.v... trong dng thi thay i theo thi gian. S tng gim ca cc i lng trn gy kh khn cho s hot ng ca h thng x l v nh hng ti vic thi vo ngun tip nhn. Yu cu t ra trong thit k l phi thc hin theo gi tr ln nht v lu lng ca dng thi. Trong cc qu trnh x l, nu lu lng dng vo tng t ngt vi bin ln s lm cho qu trnh x l b qu ti nh trng hp lng, lc,... hay mt tc dng nh trng hp phi x l ho hc hay sinh hc. Vai tr ca b iu ho nhm hn ch cc dao ng trn.Trong nhng trng hp n gin, c th kt hp nhim v x l s b viu ha dng thi trong cng mt thit b.Phn loi b iu haa. Theo chc nng: Ta c th phn bit b iu ho lu lng, b iu ho nng v b iu ho lu lng v nng .b. Theo ch hot ng: C th chia ra iu ho hot ng gin on theo chu k v b iu ho hot ng lin tc Loi b iu ha hot ng gin on thc t l nhng b cha (i khi c khuy) v c b tr thnh 2 b lmvic lun phin nhau. Loi b iu ho lm vic lin tc tu thuc theo cu trc ca dng chy trong b m ta chia ra:+ Loi y l tng (ch dng chy).+ Loi khuy l tng (ch chy xoy). thc hin qu trnh khuy trn trong cc b iu ho c th tin hnh theo cc phng thc sau:i hng dng chy theo chiu ngang, chiu ng hoc i theo ng mn. Khuy c kh bng cc loi cnh khuy.Sc kh.Kt hp hai hoc ba phng thc trn trong cng mt thit b.Yu cu v tr t b iu hoTu thuc vo h thng sn xut ca c s sn xut v phng n x l cht thi m la chn v tr t b iu ho thch hp.Thng thng, cc b iu ho lu lng c b tr ti cc ngun to ra nc thi, cn vi b iu ho nng (khi lu lng t hoc khng thay i) c b tr trong khu vc trm x l. Khi , trong s dy chuyn cng ngh ca trm x l, b iu ho c b tr pha sau b lng th, nu nc thi c cha mt lng ln cc tp cht v c khng tan vi kch thc ln. B iu ho cng c th t trc b lng , nu nc thi cha ch yu l cc cht hu c khng tan. Trng hp trong quy trnh x l c b trung ha th b iu ha gip qu trnh phn ng c tin hnh thun li.Trong mt s trng hp, b iu ho c b tr t v tr pha sau b x l s cp v trc b x l sinh hc. iu ny s lm gim c lng bn v bt trong b iu ha. Nu l mt b iu ho lu lng dng th cn phi b tr n trc c b lng s cp v b x l sinh hc v phi thit k h thng khuy trn mnh ngn cn s lng ca huyn ph, cng nh lm gim bt s chnh lch nng v i khi y cn b tr c b phn sc kh lm gim s bc mi kh chu trong cc thit b x l tip theo.Nguyn l cu to v lm vic ca b iu hoC mt s loi b iu ha nh sau:a. B iu ho c tng ngn: Loi hnh ch nht, cc tng ngn c th b tr theo chiu dc hoc theo chiu ngang. Dng chy khi i qua b phi gi ch xoy.

Hnh 7.1. B iu ho vi tng ngn a - tng dc, b - tng ngangb. B iu ho hnh trn: Dn nc vo theo ng chuyn tip: Nc thi c dn vo theo ng tip tuyn vi chu vi v tr y b v c dn ra theo ng ng trung tm nm v tr pha trn ca b.c. B iu ho c cnh khuy c kh: Loi ny rt ph bin, c th dng my khuy loi mi cho, loi chn vt hoc tuc bin. S la chn loi my khuy v tc khuy tu thuc vo nht ca cht lng. Vi cc b ln thng ta b tr lm nhiu cnh khuy v c gng gim thp khng gian cht trong b chng hin tng lng ng.d. B iu ho c sc kh: Loi ny thng dng cho cht lng c nht thp. Khng kh nn c dn vo h thng ng c c l, t y b iu ho. Khng kh nn qua l to thnh cc bong bng lm khuy o lp nc pha trn (l thng c c mt di ca ng trnh tc). Tu theo cch c l l mt hng dc hoc hai hng dc, tu theo chiu di ng s to c 1 dng hoc 2dng tun hon theo mt ct ngang ca b.Hnh 7.2. B iu ho vi thi kh nn1- Dn nc vo; 2- H thng c nc;3- Mng c ca phn phi nc, 4- ng phn phi kh c l7.1.4. Phng php pha longKhi lu lng ca dng chy trong sng ln, kh nng t lm sch ca sng cao. Trong trng hp ny, nu lu lng nc thi khng ln v xa khu dn c c th x trc tip nc thi vo sng. Trong trng hp ny, nng cht nhim c pha long, qu trnh t lm sch ca nc din ra thun li s t gy tn tht n h sinh thi thy sinh.Khi s dng phng php ny cn ch c bit ti s st gim nng oxy ho tan trong sng k t im nhn nc thi. Nng oxy ho tan trong nc sng thng ch t ti a l 10 mg/l, trong khi nhu cu oxy trong cc phn ng phn hu sinh hc cc cht hu c ln. Khi dng phng php pha long, on sng pha h lu k t im x thi thng c nng oxy thp, c th gy nh hng n vic nui trng thu sn.7.2. PHNG PHP X L HO V HO - LCc phng php x l ho v ho-l c s dng rng ri trong kim sot nhim nc thi cng nghip, c bit khi cn phi x l mc cao hoc cn phi quay vng nc. Phng php ny c dng thu hi cc cht hoc kh cc cht c, cc cht c nh hng xu i vi giai on lm sch sinh ho sauny.C s ca cc phng php ho hc l cc phn ng ho hc, cc qu trnh l ho din ra gia cht nhim vi ho cht cho thm vo. Nhng phn ng din ra c th l phn ng oxy ho kh, cc phn ng to cht kt ta hoc cc phn ng phn hu cht c hi. Cc phng php ho hc l oxy ho, trung ho v keo t (hay cn gi l ng t). Thng thng i i vi trung ho c km theo qu trnh keo t.7.2.1. Phng php trung ho1. Khi nimNc thi cng nghip c th mang tnh axit hoc kim. Tnh axit v kim th hin qua gi tr pa ca chng:pH = 7 nc c tnh trung tnh. pH < 7 nc c tnh axit.pH > 7 nc c tnh kim.2. ngha trnh c hin tng n mn, ph hu vt liu ca h thng ng dn, cng trnh thot nc, cng nh m bo pH cho php ca ngun nc tip nhn nh sng, ngi, ao h, nc thi cng nghip c tnh axit hoc kim mnh phi c x l trc khi thi vo h thng thi chung ca nh my hoc thi vo cc ngun tip nhn.Mc ch ca phng php ny l x l nc thi t c trung ho. Trong cng ngh x l nc thi, gi tr pH cho php thi ra ngun tip nhn phi theo TCVN.Mt khc, nu nc thi cn x l bng phng php sinh hc th thng trc tin phi c x l bng phng php trung ho v pH trung tnh thng l iu kin ti u cho cc qu trnh phn hy cht nhim.3. Nguyn lBn cht ca phng php trung ho l phn ng ha hc gia axit v kim hoc gia mui vi axit hoc kim c trong nc thi. Cht c chn thc hin phn ng vi cc axit hoc kim c trong nc thi gi l tc nhn trung ho ho hc.Tc nhn trung ho thng c dng x l cht thi cha axit l vi, lomit, vi cc loi, xt, sa v x l cc cht thi cha kim l kh CO2 axit sufuric. Qu trnh trung ho c th thc hin theo phng thc gin on hoc lin tc.Chn tc nhn trung ho v phng php trung ho thch hp phi da trn mt s yu t c bn sau:- Lng nc thi cn x l.- Loi nc thi (nc thi cha axt hay kim).- Cht lng nc thi ( pH, cc cht c trong nc thi v nng ca n, v.v...).- Yu cu cn x l ( pH cn t).- Tc nhn trung ho cn r tin, d kim.- Thit b n gin, d vn hnh v d ch to.- Tng chi ph sao cho nh nht.* Cho n nay c mt s phng php trung ho thng c s dng l:+ Trn nc thi cha axit v nc thi cha kim vi nhau.+ X l nc thi cha axitCho nc thi i qua lp m vi.- X l nc thi bng vi- Trung ho bng xt NaOH hoc sa Na2CO3- Nu dng thi axit thiu dinh dng (N v P) th dng Na3PO4 hocNH4H2PO4 thm vo dung dch nu tip theo s l x l sinh hc.+ X l nc thi cha kim- Phng php sc kh CO2- Trung ha bng axit sunfuric- Thi khi l qua dng thi.- Thm axit H2SO4 hoc HCl vo dng thi.- Cc phng php x l khc.Cc phn ng trung ho u to mt lng nhit ng k. Nu dng thi axit cha nhiu ion SO42- th khng nn dng CaCO3 hoc CaO lm cht trung ho v sn phm phn ng l CaSO4.nH2O dng kt ta mn s bao bc CaCO3 hoc CaO lm phn ng ngng.* La chn cc tc nhn trung ho c nhiu loi:- Loi khuy trn: Khuy c kh hoc sc kh.- Loi thp: Thp phun, thp chy mng hoc thp a.* Phng php trn nc thiPhng php n gin nht v kinh t nht l trn cc loi nc thi cha axit v kim vi nhau. Ty theo cng ngh sn xut ca tng x nghip, nh my m nc thi ca n c th mang tnh axit, tnh kim hoc c hai.Ph thuc vo ch thi, lng nc thi v cht lng ca tng loi nc thi m thc hin qu trnh trung ho 2 loi nc thi c tnh cht khc nhau (tnh axit v kim) theo phng thc trn gin on hay lin tc, thc hin trong mt ngn hay nhiu ngn ni tip nhau c khuy trn.Nu ch thi khng u n hoc nng axit hay kim trong nc thi qu cao th dng cht thi phi c iu ho lu lng cng nh nng trong cc thit b iu ha. Nh vy, m bo ch lm vic n nh trong cc thit b trung ha.Nu mt x nghip thi ra c hai loi nc thi cha axit v kim, qu trnh trn c thc hin trong mt thi gian thch hp trong cc thit b trung ho t ngay trong trm x l nc thi ca x nghip. Mt khc, cng c th thc hin qu trnh trn cc dng thi c tnh cht khc nhau ca cc x nghip cng nghip gn nhau. Chng hn mt x nghip ch thi ra nc thi cha kim. Nc thi ny c bm n trm x l ca x nghip khc gn m x nghip ny ch thi ra nc thi mang tnh axit.Th d: X nghip chuyn sn xut vt liu xy dng thi ra nc thi mang tnh kim di dng bn vi. Bn vi ny s c trn vi nc thi mang tnh axit ca mt nh my ho cht gn .Phng php trn cc nc thi mang tnh cht khc nhau l phng php x l n gin, hu hiu v kinh t. Phng php ny khng tiu tn thm ho cht, thit b n gin, tn dng dng thi ca x nghip ny x l nc thi ca x nghip khc.* Cc phng php x l nc thi axitNc thi axit thng c trong dy chuyn cng ngh sn xut ca cc ngnh cng nghip nh: cng nghip nh, cng nghip vt liu v cng nghip ha cht. Th d: nc thi ca cng ngh cn thp, x nghip sn xut thuc nhum, thuc tr su, dc phm u cha axit sunfuric, axit nc, axit clohydric.Nc thi cha axit c th phn thnh 3 loi:Nc thi cha axit mnh nh axit clohydric (HCl), axit nc (HNO3) cc mui canxi ca chng d tan trong nc.Nc thi cha axit mnh nh axit sunfuric (H2SO4) axit cacbonic (H2CO3)cc mui canxi ca chng kh tan trong nc.- Nc thi cha cc axit yu nh axit acetic (CH3COOH).Phng php ch yu x l nc thi cha axit l phng php trung ha. Khi trung ho nc thi cha axit mnh, cc mui ca chng kh tan trong nc s b kt ta v lng cn.1. Cho dng nc thi chy qua lp viPhng php ny l mt trong nhng phng php thng c dng x l nc thi cha axit. Lp vi c th coi nh mt lp m c hot tnh ho hc. Phn ng ho hc xy ra lin tc khi lp m cn hot tnh ho hc. Phn ng xy ra cc tm hot ho theo phn ng:CaCO3 + H2SO4 CaSO4 + H2CO3Vt liu lp m ngoi vi CaCO3 cn c th dng magi cacbonatMgCO3 lmit v.v...Tnh ton lng vi thch hp v duy tr tnh hot ho ca n phi da vo cc yu t.- Lng nc thi cn x l- Cht lng nc thi cn x l- hot ho ca lp m- Kch thc ca cc ht trong lp m- Ch thu ng trong thp trung ha.Tuy nhin trong thi gian s dng, tnh hot ho ca lp cng b gim i hi phi thay bng lp mi. Chu k thay lp vi ph thuc vo lng v cht lng ca nc thi cn x l. Nhc im th hai ca phng php ny l nu nc thi c nng axit ln hoc cha cc cht hu c s xut hin hin tng to bt lm gim hiu sut qu trnh x l.2. X l nc thi bng viVi thng c dng trung ho nc thi cha axit di dng bt nh cacbonat canxi CaCO3, cacbonat magi MgCO3 dng vi bt hay sa vi ca hydroxyt canxi Ca(OH)2. y l tc nhn trung ho r tin v d kim.Phn ng xy ra vi nc thi c cha axit sunfuric: CaCO3 + H2SO4 CaSO4 + H2CO3 - Qhoc Ca(OH)2 + H2SO4 CaSO4 + 2H2O - QS dng vi ti hay sa vi thng hay gp hin tng ng rn to thnh b cc ca np vi vo thit b trung ha v khi hydroxit canxi Ca(OH)2 gp khng kh s tc dng vi CO2 to thnh CaCO3, CaCO3 s ng rn v lm gim lu lng cng nh tc ng ng.Theo Nelson trung ho nc thi cha axit sunfuric v axit nc c nng 1,5% dng lmit nung vi thnh phn ca n gm 47,5% CaO, 34,3% MgO v 1,8% CaCO3. Loi ny c u im hn cc loi vi khc l gi li lng sunphat d rt nh v nh vy trnh c hin tng lng cn trong thit b phn ng.3. X l nc thi bng xt NaOH hoc sa Na2SO4Trung ho nc thi cha axit bng xt hoc sa s nhanh v hiu qu. Nu nc thi cha axit cacbonic v axit sunfuric phn ng s xy ra nh sau:2 NaOH + H2CO3 Na2SO4+ 2H2O Na2CO3 + H2CO3 2NaHCO3hay NaOH + H2SO4 NaHSO4 + H2O NaHSO4 + NaOH Na2SO4 + H2OX l nc thi cha axit bng xt hay bng sa c u im:X l nhanh v cng c hiu qu khi lng nc thi cn x l nh. Khi khng cn phi thit b x l cha kim m ch cn tnh lng cn thit v a vo trn vi nc thi u ng ht ca bm nc thi. Nu lng nc cn x l ln ngi ta c th thc hin phn ng theo phng thc gin on hay lin tc trong cc thit b phn ng. Xt c cha trong b ring v c np vo thit b phn ng theo tng m (phng thc gin on) hay lin tc (phng thc lin tc) nh bm a tc . Nc thi cn x l c a vo thit b phn ng, trong axit cha trong nc thi tham gia phn ng vi xt to thnh mui v nc.Sn phm ca phn ng phn ln dng tan v khng lm tng cng ca ngun nc tip nhn.- Tuy nhin xt v sa l nhng ho cht t hn cc tc nhn trung ho khc nh vi nn phng php ny thng c dng khi c xt v sa l nhng ph liu ca mt cng ngh khc.* X l nc thi cha kimNc thi cha kim hay gp trong cng nghip ho cht v cng nghip dt. Nc thi c tnh kim mnh phi c x l trc khi thi vo ngun nc khc.1. Phng php sc kh cacbonic CO2Nguyn l ca phng php ny l sc kh CO2 vo nc thi. Kh CO2 tan vo nc v tc dng vi nc to thnh axt cacbonic H2CO3. Khi trong nc thi cha kim, axit ny s phn ng vi cht kim (chng hn nc thi cha NaOH)CO2 + H2O H2CO3H2CO3 + 2NaOH Na2CO3 + 2H2ONu H2CO3 d: Na2CO3 + H2CO3 2NaHCO3Kh cacbonic c th l kh c cha trong bnh CO2 tinh khit. Nhng nu dng kh CO2 tinh khit th chi ph x l nc thi ln. Do ngi ta phi tn dng ngun CO2 ph thi c sn trong nh my.Ngun CO2 r tin d kim v c bt k nh my no l kh CO2 trong kh thi ca ng khi ni hi - CO2 chim khong 14% trong kh thi ny. Thit b y cn mt qut ht kh thi, ng dn kh n trm x l, mt phu lc kh tch lu hunh v bi than trc khi sc vo b trung ho. Ngoi ra, cn b phn phn phi kh kh c khuch tn u trong nc thi (t, hp ph...) trnh gy mi kh chu cho nhng qu trnh x l tip theo.Ngoi ra, ngun CO2 ph thi c th tn dng c l ngun CO2 ca thit b ln men cn ru, CO2 ca cc l vi. Vn y l tnh v mt kinh t sao cho vic thu hi CO2 v dn sc vo b trung ho tin li v n gin.2. Phng php to CO2 trong nc thi cha kim- To CO2 bng cch t kh chy di nc: Qu trnh ny c gi l s chy chm (submerged combustion) v c s dng x l nc thi nylon t trung ho trc khi x l bng phng php sinh hc. y mt h thng phi lm vic theo phng thc lin tc bao gm mt thng bc hi, mt n chy di mt nc cha trong thng bc hi, mt b trn khng kh v kh t to thnh hn hp chy.- To CO2 bng phng php ln men: Ngi ta cho ln men k kh nc thi cha kim hoc nc thi cha cc cht hu c nh cc vi khun sinh axit lm cho pH ca mi trng gim.Kt ta l qu trnh chuyn cc cht ho tan trong dung dch sang pha rn da trn ho tan ca cc hydroxit hoc cc mui v c. Qu trnh c ng dng tch cc kim loi Zn, Cd, Cr, Cu, Pb, Mn, Hg... ra khi nc thi dng kt ta hydroxit kim loi M(OH)2 hoc dng sunfit kim loi MS.Tc nhn kim loi l sa vi Ca(OH)2 v NaS Phn ng xy ra nh sau:M2+ + 2OH- = M(OH)2Na2S + MSO4 = MS + Na2SO4M2+ l kim loi nng. ha tan ca a s M(OH)2 v MS ph thuc vo pH.a s cc MS c ho tan gim khi pH tng cn phn ln cc M(OH)2c tan cc tiu pH nht nh.3. X l nc thi cha kim bng axit sunfuricy l phng php trung ho gia kim v axit. Nu nc thi cha axit th phn ng xy ra nh sau:Tng t nh phng php x l nc thi cha axit bng xt, phng php ny c u nhc im:- Lng tc nhn trung ha nh.- Tc phn ng ln, qu trnh xy ra nhanh dn n hiu qu qu trnh cao. Song gi thnh dng tc nhn trung ha l axit thng cao so vi dng kh thi CO2 Ngoi ra axit m c c tnh n mn nn gy kh khn cho qu trnh cha, dn v np axit vo b trung ho. Thng nhng thit b cha ng ng dn axit c trng mt lp vt liu chng n mn axit.7. 2.2. Phng php keo tTo bng l qu trnh lm keo t cc ht keo hoc dnh cc ht nh li thnh mt tp hp ht ln hn lng bng cch a vo cht lng cc tc nhn to bng c tc dng ph keo hoc hp ph cc ht nh ln b mt ca n hoc dnh cc ht nh li vi nhau.Cc cht thng dng trong phng php lng v ng t d loi b cc cht rn l lng trong nc thi l:- Phn Al(SO4)nH2O (n = 13-18).- Sa kt hp vi phn Na2CO3 + Al2(SO4)3- St Sunphat FeSO4.7H2O.- Nc vi Ca(OH)2.- Natrialuninat Na2Al2O4- St Clorua v st (III) sunphat FeSO4Th d:+ Dng phn loi b photphat trong nc thi:Al(SO4)3 + PO 3-

AlPO42-

+ SO4 pH ti u: 5,6 - 6+ Dng vi loi bicacbonat, cacbonat photphat, magi.+ Dng st clorua to photphat

+ Dng natri aluminat loi photphatC ch to bng trong mi trng hi kim:Vi mui st cng c phn ng tng t.Cc Al(OH)3 v Fe(OH)3 l keo dng, cc ht bn trong nc l keo m s trung ho v dnh vo nhau hoc cc ht keo Al(OH)3 v Fe(OH)3 s hp ph cc ht bn vo n lm thnh tp hp ht d lng hn.Tc nhn to bng cn l cc cht hu c, v d: Polyacryamit khi a vo nc thi do cu to mch di ca n s c nhng ch tch in s ht nhng ht keo m vo n v theo c ch bc cu, cc ht bn trong nc s bm vo nthnh tp hp ht ln hn do lc hp ph.Hnh 7.3. Thit b to bng bi khuy c kh7.2.3. Phng php oxy hoa. Ozon ho:Ozon l cht oxy ho c hot tnh cao v ho tan trong nc ln gp 10 ln O2. N bn trong mi trng axit hn so vi mi trng kim.Phng php ny thng dng x l nc thi c cha cc cht bn hu c dng ho tan v keo. c tnh ca ozon l c kh nng oxy ho rt cao, d dng nhng oxy nguyn t hot tnh cho cc tp cht hu c. Oxy ha bng ozon c th dng lm sch nc thi khi phenol, sn phm du H2S, hp cht ca As, hp cht b mt, CN-, cc cht mu, hyrocacbon thm, thuc tr su...., c kh nng tiu dit cc vi khun. Nu kt hp chiu tia cc tm th tc oxy ho bng ozon s tng 102 - 104 ln.Phn ng oxy ho cyanit bng ozon c dng:CN- + O3 = CNO- + O2Thit b ozon ha c nhiu dng loi m, loi thp si bt...Hnh 7.4. Thit b loi m thc hin phn ng oxy ho bng ozon.b. Oxy ho bng peroxyt H2O2H2O2 l cht oxy ho mnh dng oxi ha phenol, CN-, cc hp cht cha S v cc ion kim loi. Qu trnh xy ra mnh lit khi c mt ca cht xc tc nh Fe++, Fe+++, Cu++ Cr+++, pH ti u 3 - 4.c. Oxy ho bng pemanganat kaly (KmnO4)KMnO4 l cht oxy ho tng i mnh c dng oxy ho phenol, CN- v cc hp cht cha S, pH ca qu trnh l 9,5, pH cng cao th phn ng xy ra cng nhanh. Phn ng bng pemanganat kaly c dng:C2H5OH + 4KMnO4 = 4MnO2 + 2K2CO3 + 3H2OThit b dng thc hin qu trnh oxy ho thng l loi khuy trn nu cc cht phn ng l th lng hoc rn- lng v l loi thp nu l th lng- kh.7.2.4. Phng php khQu trnh kh cng l thc hin phn ng oxy ho kh c dng lm sch nc thi khi cc hp cht Hg, Cr, As. kh Hg v cc hp cht hu c cha Hg cc cht kh thng dng lFeS, NaHS, bt Fe, bt Al, H2S. Trong qu trnh kh cc hp cht hu c chaHg, ban u cc hp cht cha Hg b phn hu sau cc ion Hg+ s b kh thnhHg kim loi v c tch ra khi nc bng cch lng, lc... As trong nc thinm dng ASO -, AsO 3-

, AsS2-

, AsS3. tch As khi nc thi ta tin hnh kh As thnh hp cht kh tan nhAs2O3 v c tch ra rng tch lc.CrO42- trong dung dch thng b kh n Cr3+ bng than hot tnh, SO2, NaHSO3, NaHSO4.....Phn ng kh CrO42- bng NaHSO3 khi pH = 3 - 4 c dng:Phn ng kh cro bng So. pa = 2 2,5 c dng:

7.2.5. Phng php trao i ionTrao i ion l qu trnh tng tc ca dung dch vi pha rn c tnh cht trao i ln trong pha rn vi cn c trong dung dch. Qu trnh c dng tch cc kim loi Pb, Zn, Cu, Hg, Cr, Ni, Cd, Mn... hp cht As, P, CN cc cht lng phng x khi nc thi.Trao i ion c th s dng vi cation v anion hu c hoc v c. Tuy nhin, phn ln cc ng dng trao i ion u lin quan n cc loi cht v c v cc loi cht hu c thng i hi cht ti sinh c nng rt cao hoc s dng cc dung mi hu c kh cht hu c. Ni chung, cc ion in tch cao d to ra cc mui bn vng vi cc cht trao i iom so vi cc ion c in tch thp v cc loi c ho tr cao thng d b kh khi dung dch so vi cc loi c ho trthp.7.2.6. Phng php hp phHp ph tch cc cht hu c v kh ho tan khi nc thi bng cch tp trung cc cht trn b mt cht rn (hp ph vt l) hay bng cch tng tc cc cht bn ho tan vi cc cht rn (hp ph ho hc).Phng php hp ph dng kh mi v, mu, cht bn hu c kh phn hy, kim loi nng,... ra khi nc thi cng nghip. Phng php ny thng c s dng khi nc thi cn x l t tiu chun cao hoc ti s dng li ncthi.Trong phn ln cc trng hp, phn