Chương 3 xu ly nuoc thai trong cong nghe loc hoa dau

8/2/2019 Chng 3 xu ly nuoc thai trong cong nghe loc hoa dau

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Chng 3: Nc thi trong lc ho du.

G i i t h i u c h u n g

1.1. Nc thi: nguyn nhn ch yu gy nhim mi trng Nc l ngun ti

nguyn qu gi khng th thiu i vi conngi cng nh s pht trin ca x

hi loi ngi. Nhu cu vnc sch ngy cng tng theo nhp pht trin

th pht trin cng nghip v pht trin x hi. Ngoi ra, nhu cu vnc tiv

nui trng thc vt, ng vt ngy cng nhiu. Cht lng nc cho mi i

tng rt khc nhau, nhng c mt iu c bn l con ngi, cy trng, vt nui

tiu thnc cn c pht trin bnh thng, khng b nhim c trc mt

cng nh ludi. iu t ra mt vn l cn bo v ngun nc cng nh

mi trng xung quanh ta m bo cuc sng lu bn ca loingi trn tri

t. thc hin c iu ny, chng ta cn bit v nhim ngunnc, tc

nhn gy nhim cng nh cc bin php khc phc. Nh chng ta bit,

nhim ngun nc do nc thi t khu vcdn c, t cc nh my cng nghip,

thng nghip v dch v, tkhu vui chi gii tr, trng hc, bnh vin do nc

chy trntrn mt t v nc ti tiu thu li ko theo cc cht mu cat,

thc trsu, phn bn vo cc ngun nc ao h, sngngi, bin v k c

nc ngm. Trong c thcoi nc thi lngun nhim chnh. Chng ta cn

thng nht v khi nim nhim ni chung l: trong mi trng b nhim, khihm lnghoc nng cc tc nhn trong o t n mc c nh hngxu

n i sng con ngi, sinh vt sng trong hoc s dngn.Do nhn thc

nh vy nn hu ht cc quc gia u c nhngchnh sch bo v ngun nc c

lut bo v nguyn nc hay lutkim sot nhim ngun nc. Chnh cc tiu

chun cht lngnc l snh lng ca lut ny.Tiu chun cht lng nc

l gii hn hoc nng ti a cc tcnhn gy nhim c cho php vi tng

i tng c th vtrong t vng lnh th c th, nhng cng c cc tiu chun

c bnchung. Mt khi nng hoc gii hn cc tc nhn gy nhim

vt qu tiu chun, mi trng nc ti c th xem l bnhim mc d chac bng chng v tc hi nhim c th.Hu ht cc trng hp gy nhimngun nc u do hot ngca con ngi. Cc ngun gy nhim ngun ncch yu lnc cng nghip, nc thi sinh hot.I.2.


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Nc thi cng nghip Nhiu ngnh cng nghip tiu th v thi ra mt lngnc khngl, nh cc nh my luyn kim, ho cht, lc ho du, dt nhum,ch

bin thc ph. Nc qua s dng trong cc qu trnh snxut, nc lm mtthit b v sn phm, nc lm v sinh nhxng, my mc v thit b, nc sinhhotu c coi l ncthi. Thnh phn v tnh cht ca nc thi rt a dng,

ph thcvo tng qu trnh sn xut, vo trnh v bn thn dy chuyncngngh.Trong cc x nghip cng nghip cn c loi nc thi quy c lsch. lnc lm ngui thit b, nht l cc nh my in.Tuy khng bn nng sau khdfng n c th c nhit cao, kotho g st cc thit b trao i nhit, ngng hoc do ngunhin b s c lm cho nc b nhim bn. Nc thi loi nylmcho ngun nc tng nhit d, ngho oxi ho tan,.. c th lm chtcc sinh vtnc hay c cc tc ng xu khc nn chng cngcn x l khi cn thit.Lngnc thi ca cc nh my cng nghip nng thng t 9-14m3

/ha/ngy ca cc nh my cng nghip nh t 14-28m3

/ha/ngy. C th tnh theo s lng nc cp u vo; khong95% nc qua sdng trong cc nh my, phn xng v qutrnh cng ngh l nc thi(ngoi l cc nh my bia, nc giikht, nc khong).Phn loi nc thi cng nghip:

Nc thi cng nghip c thchia thnh hai loi. y chnh l nc thi ra ca ccmc ch sdng khc nhau trnh by trong phn trc.+ Nc thi khng tipxc trc tip: bao gm-

Nc lm nguyn liu ni hi-

Nc lm mt, nc gia nhit, nc ngng t lm mt(traoi nhit gin tip)Nc thi tip xc trc tip: bao gm-

Nc dng vn chuyn cc sn phm, vt liu hay hocht-

Nc lm sch v sc ra thit b, sn phm, sn-

Nc ho tan, nc pha long(lm long)

-Nc lm mt hay gia nhit tip xc trc tip(trao i nhittrc tip)-

Nc tho bnhI.3.

Nc lm nhim mi trngTrong nc thi ni chung cha nhiu cht bn, chi v ccvi sinh vt. Nc thi khng c x l thch ng nu cho chyvo a h,


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m ph, sng ngi, bin.. s lm cho mi trngnc ca c khu vc ny b nhim, gy hu qu xu i vingun nc. Nc thi cha x l c mt s nhhng ti ngun nc nhsau:+ Lm thay i tnh cht ho l, trong, mu, mi,v/ pH,hng lng cc cht hu c, v c, cc kim loi nng c ctnh, cht ni,cht lng cn..+ Lm gim oxi ho tan do tiu hao trong qu trnh oxi ho ccchthu c.+ Lm thay i h sinh vt nc, k c vi sinh vt, xut hin ccvi sinh vtgy bnh lm cht cc sinh vt trong ncKt qu l ngun nc c th khng sdng c.Cc cht bn, c hi trong nc thi cng nghip thwongf ctnh chi i vi thu sinh. Nng cc cht hu c trongnc thi qu cao s sinh raiu kin k kh. Cc cht dinhdng trong mi trng tng cao s dnn hintng phttrin to. Cc cht c hi c trong nc thi l nh hng xun traoi cht hoc sinh trng. Kt qu l s lng c th vs loi thu sinh b gimdn. Nc thi chy vo cc ngun nc lm nhim cc ngunnc . Ngi tachia cc ngun nhim nc+ nc bn nh hoc hi bn : Hm lng cc cht

hu cp thpc ion amon v clorua.Ncc bn va( bn trung bnh) : Nc b thay i cc tnhcht t nhin donc thi chy vo+ Nc bn vaaf rt bn : Nc hon ton mt tnh chttnhindo nc thi chy vo qu nhiu1.4-Thnh phn nc thi- Tc nhn gy nhimTrong nc thi c th cha nhiu thnh phn khc nhau vchng l tcnhn gy ra nhim. C th chia chngg thnh ccloi sau:+Cc cht hu c(bnv d b phn hu )+Cc cht rn+Cc kim loi nng+ Cc cht v c + Du m +Cc cht phng x+Cc cht c mi+Cc vi sinh vtA-

Cc chthu c :Cc cht hu c nhim vo nc c cha thnh hai loi theokhnng b phn hu sinh hc+Cc cht hy c d b phn hu : nh hydrocacbon ,cht bo , mt s cht c ngun gc thc vt,. . . Cc cht ny tiu thoxi ho tantrong nc , lm gim lng oxi ho tan trong nc+Cc cht hu c kh b phnhu: nh cc hydrocaccbon vng thm , cc hp cht a vng ngng t , ccclorua hu c ,ccc polime, Cc cht ny kh b phn hu do tc nhn sinh hc

bnh thng nn c th tn ti lu di , gy c hi c mi trngv cconngiCc cht hu c c th chim 55% tng s cht rn ,75%tronghuyn ph vkhong 45% trong cc cht rn ho tanMt s hp cht hu c c c tnh cao nh

phenol v cc hpcht ph nol, cc cht bo v thc vt v mt s cht c ngun

gcthc vt .b-Cc cht v c.Trong nc thi c th cha nhiu cht v c khcnhau vchng thng tn ti dng ion . Mt s ion c trng thng gptrong nc thi l amon(NH4+)hay amoniac(NH3),ntat(NO3nhhng n muhay thiu mu),photphat(PO4gy c hi ),sunpht(SO4gy g ng ng,n mn b tng ,st ho,),clorua(Cl,to v cn,)c-Cc kim loi nngTrongnc thi gy nhim nc cn c ch trng n ccion lim loi nng v chng


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thng c. Cc lim loi nng thng lch (Pb nh hng n mu, no ,c thgy cht ngi ,),thungn ( Hg c hi ,),asen(,cc c,gy cht ngi , t bin ,ung th,)d- Cc chtrn:Cc cht rn c th l cht hu c, cht v c hay cc sinh vt.Chng c th tn ti dng keo hay huyn phe- Cc cht mu :Mu nc thithng do mu ca ccc tc nhn gy nhimnh mu nu en do cc cht huc, mu vng do st hocmangan ,g-Cc cht mi:do cht hu c b phn huhay do cc ho cht , du m ,h-Sinh vt:C nhiu loi vi sinh vt ,vi rt,to,ru,1.5-Cc thn quan trng ca nc thi v nh gi cht lngcht thiKhicp nc ,cc ch tiu quan trng cn xem xt l pH,trng,hm lng st, cng ,hm lng mangan,ch s cli. vinc thi cn quan tm n mt sthng s nh sau:+ Hm lng cht rn:-Tng lng cht rn ho tan(c mu nc

cn thnh cn ri sy 105 C)- Cht rn qua lc du v khng qua lc du (lcmu bng mulc tiu chun,sy kh 105 C)+ Mu sc v mi+ Cc thng snh gi cc cht hu c trong nc thi:

Nhu cu o xi ho cc hp cht hu c c trong nc thi (mg02/l) cht o xi homnh thng dng xc nh COD l bcomat kali(k2br2o7)-

Nhu cu o xi sinh hc (BOD)+ Xc nh tnh c hi ca nc thi:-Xc nh 1 scht hu c c c tnh nh phenol,thuc bo vthc vt,..- Xc nh mt s chthu c c c tnh nh thu ngn,ch,asen,..+ Xc nh mt s in v c c trongnc thi nh NH4,NO3,PO3,SO4,Cl+Xc nh vi sinh vt gy bnh.1.6 Qun lcht lng cht thiTrong qsun l mi trng nc, ngi ta thng dng cchthng tiu chun cht lng nc nh:+ Tiu chun nc cho cc mc ch khcnhau+ Tiu chun dng nc thi+ Tiu chun dng sng (dng cha ncthi) qin l cht lng nc thi thng dng tiu chundng ncc thi . Vinc thi cng nghip gi tr cc thngs v nng cc cht nhim theo TCVN5945 1995.Cng c th tham kho cc h thng tiu chun cht lngnc thikhc nh tiu chun ca M,Anh ,c,Nht, n ,..hay tiu chun quc t.Bng 3.1 : Gi tr gii hn ccc thng sv nng cht nhim trong nc thi cng nghip theo TCVN 5945-

1995T T T h n gs n v 1234567


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89101112131415161718192021222324252627282930313233Ghi ch

:KPH:Khng pht hin c Nc thi cng nghip c gi tr cc thng s vnng cc cht:


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Ct B


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nhhng n con ngi v ng vt Trc y ,qu trnh th ho v cngnghip ho cha pht trin th vn x l ncc thi cn n gin . n nay ,ticc nc pht trin cng nh cc nc ang pht trin vn ny tr thnh vn cp bch v khng th khng t ratrong quy hoch pht trin.1.7.1- Phn loiqu trnh v phng php x l nc thi Nc thi thng cha rt nhiu tp chtc bn cht khc nhau .V vavy mc ch ca x l nc thi l kh cc tp cht saocho nc sau khi c x l t tiu chun cht lng mc chpnhnc theo cc ch tiu t ra . Cc tiu chun cht lng thng ph thucvav mc ch v cch s dng : nc s tis dng hay thi thng vo cc nguntip nhn trc . tc mc ch trn , trong cng nghx l ncc thi sdnggnhiu phng php v qu trnh x l khc nhau.a-

Cc phng php x l nc thiC nhiu phng php x l nc thi nh ccphng hp c hc, l hc, ho hc v sinh hc. Thng thng, cng ngh x

lnc thi s dng kt hp nhiu phng php to thnh bin php( h thnghay qu trnh) x l nh x l c-l-ho hc; x lkt hp cc bin php sinh hc vc-l-ho hc. Bin php saucng c nhiu u vieetj v hiu qu kh cao, nc cth ti sdng cho cc mc ch khcnhau. Cc phng php x l inhhc c sdng nhiu vi hiu qu cao, c bit i vi ncthi c ca nhiu cht hu c d

b phn hu nhng t hiu qui vi nc thi cng nghip c cc cht v c chi hoccc cht hu c bn vng v cng t hiu qu i vi mt viloi sinh vt gy

bnh.+ Cc phng php x l nc thgi bng cc bin php c-l-ho hc: c 5phng php c-l- ho hc c dng x lnc thi li:-

Phng php lng v ng t(keo t): loi b cc cht rn vcc cht l lng(huyn ph).-

Phng php trung ho axit hoc kim-

Phng php chit tch-

Phng php dit khun v phn hu cc cht c

1)Phng php lng v ng t: Dng mt s cht lm tc nhnlng v keo t nh-

Phn nhm Al

2

(SO4)

3


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.nH

2

O(m=3-18)

-

Sa kt hp vi phn: Na2

CO

3=

+AL

2

(SO

4

)

3

-Sunphat st(II): FeSO4

.7H

2

O

-

Aluminat natri: Na

2

Al

2

O

4

-

Clorua v sunphat st(II): FeCl3

v Fe

2

(SO

4)

3

-

Nc vi : Ca(OH)2


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Mt s tc dng ca cc cht trn i vi cc cht nhim nh:( Vitphong trnhvo)

2)

Phng php hp ph: Dng mt s cht hp ph tch cccht nhim. Cccht hp ph thng dng l than hottnh, than bn sy kh, t st hot tnh,diatonmit, betonitCc cht hu c, cc kim loa nng v cc cht mu d b hp

ph. Lng cht hp ph s dngt u thuc vo kh nng hp ph ca tng cht vhm long cht bn c trong ncthi. Phng php ny c tc dng tt, c thhp ph c85-95% cc cht hu c v cc cht mu. loi b kim loi nng,cc cht hu c, vc c hingi ta dng than bn hp ph v nui bo tytrn mtnc.3)

Phng php dit khun (kh trng): nc thi sau khi cx l bng cc binphp cn thit, trc khi a vo ngunnc cng nh ti s dng cn phi st

khun. Cht stkhun thng dng v t c hi l kh clo hay hp cht clov mt s cht oxi homnh khcVic clo ho nc nm dit cc vi sinh vt, to v lm gimmi canc. Cc hp cht clo tdng y l clo lng, cloruavi c lng clo 25-35%,cc hypoclorit NaOCl, Ca(OCl)

2

vac hot tnh ca clo va c tnh oxi ho nn c th phn huc nhiu chtc hu c thnh cc cht khng hay t c+ Phng php x l nc bng bin

php sinh hc: thngdng 2 nhm phon gphp l-

Cc phng php hiu kh(a kh)-

Cphng php k kh Ngoi ra c th dng 2 phng php hp ph l phongphpthiu kh v phng php tu nghi1)

Phng php hiu kh: Dng ao h n nh nc thi, dngcc b hiu kh v kthut bn hot tnh hoc dng phng php lc v a quay sinh hc(mng sinhhc) loi bBOD, natratPhng php hiu kh da trn hot ng ca qun thvisinh vt hiu kh oxi ho cc cht hu c bng oxi ho tan ctrong nc. Kt qu

l cc cht nhim bn b phn hu vnc oc lm sch2)

Phng php k kh(yu kh): Phng php ny c dng loi b cc cht huc trong phn cn lng v bn y bng cc vi sinh vt k kh v k kh tu tinCth dng ao h k kh, h thng b phn ng k kh haycc b to kh sinh hc.b-


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Cc qu trnh x l nwocs thiTheo cht lng nc thi t c, cc qu trnh xl ncthi c tp hp li thnh cc cng on x l: x l cp I,x l cp II v xl cp III+ X l cp I: x l cp I gm cc qu trnh x l s b vlng, bt u tsong(li) chng v kt thc sau lng cp I.Cng on ny c nhim v loi b ccvt rn ni c kchthc ln v cc tp cht rn khc ra khi nc thi bov

bm v ng ng. Hu ht cc cht rn l lng lng li b lng cp I. Khu vc ny thng gm cc qu trnh lc qusong(li) chng,lng, tuyn ni, tch du m v trung ho.+ X l cp II: x l cp II gm cc qutrnh x l sinhhc(i khi c qu trnh x l ho hc) c tacds dng loi bhu htcc tp cht hu c ho tan c th phn hu bng conng sinh hc, ngha l khBOD. Cc qu trnh l:dng bn hot tnh(hot ho bn), lc sinh hc hay oxihosinh hc trong cc b, h sinh hc v phn hu ym kh, hiukh. Tt c ccqu tnh ny s dng kh nng ca cc visinh vt chuyn ho cc cht thihu c v dng n nhv nng lng thp.+ X l cp III: x l cp III gm c qu

tnh x l vi lc, ktta ho hc v ng (keo) t, hp ph bng than hoth tnh,traoi ion, thm thu ngic, in thm tch, cc qu trnhkh cc cht dinh dng,clo ho v ozon ho.Trong thc t vic la chn cc phng php lm schncthi tu thuc vo mc sch cn thit v hiu qu lmsch ca cc phng

php, cc cng on hay qua trnh x l.C th hanm kh bng sau la chnphng php x l.Bng 3.2: Hiu qu lm sch ca c qu trnh khc nhautrongx l nc thi2. Nc thi t cng nghip lc ho du2.1. Gii thiu2.1.1. Ccvn mi trng c bn ca cng nghip du mCng nghip du m c th phn chia thnh ba lnh vc ch yu:sn xut(tmkim, khai thc) du m, lc v ho du v tiu thsn phm. Sn xut bao gmcc qu trnh lin quan n tm kimv khai thc du, ly du t lng t, x l s

b ti gin khoan vvn chuy du th n nh my lc du. Quy m ca x l sbtu thuc v kiu du th v thng bao gm vic lo b kh vnc bin. Lcho du bao gm cc qu trnh cn thit chuynho du th thnh cc snh

phm c th bn v nhiu qu trnh ch bin ho hc khc tao ra nhiu sn phmc c tnh khc nhau.Tiu th lin quan n ton b cc hot ng phn phi v

bn ccsn phm du m trung gian v cui cng.Tt c cc hot ng ny cnhng tc ng n mi trng.Bn vn mi trng c bn tp trung trongcng nghip du ml:+ Lu hunh tng nhin liu du+ Bc x t+ Trn du do

s c khoan hay vn chuyn du+ Cc dng chy v pht x t nh my lc du,nh my ho chtv cc hot ng khc Nh vy nc thi lc ho du l mttrogn cc vn c quantm, nghin cu2.1.2. Cht thi lc du v hoduTrong hot ng lc du, cc cht nhim c th c thi vomi trng.Cc cht nhim l cc sn phm ph ca cc qutrnh lc khc nhau. Cc chtthi c bn t lc du bao gm+ Sunphua hydro(H2


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S): y l cht kh tin thana ca oxit luhunh(SOx

), chng c to ra khi x l bng hydro( nhreforming xc tc, hydrotreating vhydrcacking) v cc qu trnhcracking (nh cracking xc tc, cracking nhit haycc ho). Mtlng khng ng k c to ra trong cc qu trnh khc (nhchngct, sn xut atphan, sn xut du bi trn, alkyl h..) . Oxitlu hun xng octo ra khi chy cc cht lng cha luhunh. Tng t nh vy, khi cc nhinliu cha nit hay hpcht nit c t chy s to ra oxit nit(NOx

+ Hi hydrocacbon: hi hydrocacbon c th bay ra t cc b cha(du th, snphm)+ Mono oxit cacbon (CO): y l sn phm ph ca qu trnhcracking xctc hoc bn cnh bi xc tc cng gy nh hngn mi trng+ Cc cht tora nhu cu oxi sinh hc(BOD) trong nc thi: cccht ny c to ra trong ccqu trnh chbin nh cracking xctc, cracking nhit, x l cc sn phm du m

bng axit sunphuric.Phn ln cc dung mi(nh phenol, phuphural) c dngtrongsn xut du bi trn bng phng php chit lc cng to ra nhucu BOD.+

Nc thi t cc nh my lc duc th chga du v nhiu chtkhc hoc nckhng trung tnh (pH7)Do cc cht thi trn c nh hwongr xu n mi trngnn chngcn c x l trwocs khi thi vo mi trng. C mt s qu trnhkimsot cc cht thi t nh my lc du nh+ Loi H2

S (phn ng to SOx

khi chy):

-

Cd kh cha H2

S c x l bng cht lng(thng l dungdch amin) c kh nng hp th H2

S. H

2

S sau oc thu hikhi hn hp lng. Cng c th chuyn ho n thnhlhunh ri thu hi

-Tch chua: cc dng nc thi t lc du cha H2

S c tch bng hi nc loi b H2

S+ Loi hi hydrocacbon(phn ng to khi c):-


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Lp cc mi vm ni hoc h thng thu hi hi trn ccthng cha.-

Bo qun tt, trnh r r+ Loi du v cc hp cht hu c lng khng ckh nngho tantrong nc ( t nc thi, c hi vi mi trng nc, gy bn)-

Dng cc thit b phn tch du nc (thit b tch API,CPI..) Du c cho nitrn b mt nc bn v wocj ht b .-

Sc kh: khng kh c thi qua nc bn, du ni ln bmt nh bt v c htb+ Loi cc h cht ho tan trong nc( ho tan trong nc thi,gy tn hi n mitrng nc, gim lng oxi ho tan, mi khchu): dng cc phng php x lsinh hc nh mng lc sinh hchay bn hot tnh.+ Loi hp chtphenol(c vimi trng sng)

-Thu hi v bn cho cc nh my ho cht-

t b-

Chn trong b cha-

Dng cc phng php x l bng hydro loi bt nhu cutch phenolDi yl mt s thit b c dng x l cht thi lc du:+ H2

S c x l trong cc phn xng c thit b ra kh, chuynho thnh S+ Dngcc mi che thng cha+ Loi b BOD trong cc phn xng x l cht thi c ccthit btrung ho nc, thit b tch du, thit b lc n, thit b lng, thit b ngt v thit b x l sinh hc+ Du v cc cht rn l lng c thu hi v trung hotrong cc phn xng x l nc thi n gin hn khi loi b BODTrong h du,cht thi a dng hn nhiu v tu thuc vo ccqu tnh sn xut khc nhau. Tuthuc vo tng loi cht thimngi ta chn phng php x l thch hp. Xuhng hin nay ldng cc cng ngh tin tin, gim thiu lng cht thi cn xl.2.2. Nc thi lc ho dua-Ngun v lng nc thi Nc thi t nh my lc

du l rt a dng tu thuc vo cc qutnhv cc phn xwongr ch bin c bnca nh my.Cc ngunch y ca nc thi trong nh my lc du l+ Nc thini hi v nc thi t qu trnh x l, chim khong65%, trong nc chuachim khong 25%+ Nc thi t lnh vc lm mt, chim khong 20%+ Nwocsthi sinh hot v nc ma, chim khoang r15% Nh vy nc thi t ni hi vt cc qu trnh x l chim n2/3 tng lng nc thi (c th n 10000-15000m


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3

/ngy mhoc ln hn). Nc lm mt chim n hn 90% tng lng nc s dngtrong nh my lc du nhng ch ng gp khong 20%tng lngthi.Lu rng nc thi cha H2

S, NH

3

v du c coi l nc chua. N c th c tch bng hi nc loi b H2

S, NH

3

v cc khnh. Sau chng c thu hi hay t b b- Phn loi Nc thi lcdu c th gm c loi sau+ Nc c to ra hay loi b trong cc phn ng+

Nc ra lm sch cc thit bi, h thng, nc tho b d tr.+ Lng ln nc

chua c tch t cc qu trnh tch v nwocst ni hi thi ra+ Nc kim vamin sdng thi ra t cc thit b x l sn phm v cc phn xng x l+

Nc thi t thp lm mt thi ra+ C th l nc ma nhim gm nc tho bmt t cc phnxng x l lc du, cc phn xng ph tr v cc khu vcngi, vn chuyn+ Cc ngun nc ma t cc khu vc khng nguy him+Dng nc thi sinh hot.c- Cc cht nhim ch yuCc cht nhim ph bint nc thi lc du bao gm+ Du v m + Cc hydrocacbon+ Phenol v hpcht phenol+ Cc hp cht sunphua+ Cc cht ra ho tan+ Cc chthu c didng COD v BODd- c tnh nc thiCc c tnh in hnh ca nc thi tnh my lc du cho trong bng sau:Bng 3: Cc c tnh in hnh ca nc thilc duT T c t n hK h o n g g i t r e-Nc thi t mt s qu trnh x l1) Phn on du th( chng ct kh quyn,chng ct chn khng,tch chn khng..)Cht thi t qu trnh phn on du thc th t 3 ngun-

Th nht l t nc tho ra t cc bnh thu gom nh(bnhngng t nh trckhi tun hon(hi lu) hay chuyn cchydrocacbon ti cc thp phn on khc.

Nc tch t cchydrocacbon trong cc bnh tu gom c ly ra v thixungh thng cng ranx. Nc ny l ngun ch yu cacc hp cht sunphua, c bitkhi chng ct du chua (ch bin du chua): n cng cha mt phnng k du,hpcht clua, cc mecaptan v cc hp cht phenol.-


14/42

Ngun thi ng k khc c thi ra t cc ng ly mu,du ny c th ctch nhng c th to nh tng trongh thng nc thi. C th coi y khng

phi nc thinhng li gy nhim ngun nc.-

Ngun thi th ba c th l nhng nh tng du to ra trongcc bnh ngng tbaromet( thit b ngng t trc tip) cdng to p sut thp trong cc thpchng ct chnkhng. Tuy nhin khi c thit b ngng t baromet oc thay bngcc thit b ngng t b mt th hi du khng tip xctrc tip vi nc na vkhng to ra nh tng. Tt nhin,nu dng nc ngng t th mi to ra ncthi.2) Cracking nhit (c lin quan n cc qu trnh cc ho chm,cc ho tngsi, cracking nhit, cracking gim nht:visbreaking)

Ngun thi chnh trong cracking nhit l t thit b thu gom trnnh thp phnon. , nc c tch ra khi hi hydrocabonv chy vo h thng cngrnh. Nc ny thng cha cc phnon du v c th lngun BOD, COD,

amoinac, phenol vsunphua cao. Ngun thi ny c pH kim v c th c kimcao.3) Cracking xc tc: (cracking xc tc tng si(gi si) hay m cnh)Cc

phn xng cracking xc tc l mt trong nhng ngun ncchua ln nht trongnh my lc du. nhim t cracking xc tcnhn chung l do cc thit b tch hinc v cc tht b thu g nh ca cc thp phn on c dng thu hi vtch cc phn on hydrocacbon khc nhau trong cc thit b phn ng xctc. Cccht nhim chnh t qu trnh cracking xc tc l du,cc sunphua, hp cht

phenol v amoniac. Cc cht nhim lm cho nc thi c tnh kim cao cngnh nng BOD vaCoD cao. Nng phenol v sunphua trong nc thi thayitheo loi du th x l nhng nh chung rt ng k.4) Cracking bng hydro(hydrocracking): Nhiu qu trnh lin quannh Isomax, BASF_IFPhydrocracking..)Trong cc thit b tch v phn on sn phm pha sau cc thit

b phn ng hydrocracking c mt lng H2

S ho tan trong nc. Nc thi t cc thit b tch hythps phn on c th chmlng cc hp cht sunphua cao v c th c phenol cng nhamoniac.5)Reforming(reforming xc tc, reforing nhit..)Reforming l qu trnh tng isch, lng nc thi l khngng k. Th tch ca dng thi l n v khng ccc dng thi cnng cc cht nhim cao. Cht thi l kim v cht

nhimch yu l sunphua t thit b thu gom nh ca thp tch cdng loib cc phn on hydrocacbon nh t thit b phnng i ra. Thit b thu gom nh cha mt lng nc do c thcha trong hi hydrocacbon. Ngoi sunphua,trong nc c thcha mt lng nh amoniac, cc mecaptan v du.6) Polimeho: (polime ho axit, polime ho nhit..)Phn ln nc thi l t qu trnh x l s b nguyen liu trc khia vo thit b

phn ng. Ngi ta dng cc thp ra nc v ccthit b ra axit x l nguyn


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liu. Nc thi c th c hmlng sunphua, cc mecaptan v amoniac cao.7)Alkyl ho(alkyl ho bng H2

SO

4

hay dng HF) Nc thi l mt trong 3ngun cht thi ca qu trnh alkylhodng axit. Nc c rt ra t cc thit b thu gom nh chahm lng duv cc sunphua khc nhau v cng c cc cht bnkhc. Nhng y khng phi lngun chnh ca qu trnh ny.9) X l bng dung mi: (hydrotreating): ( c nhiuqu trnh khcnhau nh HDS, HDN, ..)Lng cht thi tu thuc vo qu tnhc dng v nguyn liux l bng hydro. Cc dng thi t cc thit b thu gom nh cacc thp phn on, cc thit b tch hi nc v y cc thp tchncchua. Cht nhim ch yu l c sunphua v amoniac. Cth c c cc hp cht

phenol nu nguyn liu c khong nhit si cao.10) Loi atphal(deasphanting)

Nc thi c thi ra t cc thit b ngng t nh ca cc thptch hi ncc dng tch atphan v propan. Nc chua tcc thit b ngng t c thcha mt lng nh cc sunphua, duv amoniac.11) Qu tnh lm ngot(sweeting)

Nc thi ra xut pht t nc ra sch sn phm x l v tisinh dung dchx l nh dung dch plumbua natri(Na2

PbO

2

). Dngthi ny cha mt lng nh du v dung dch x l nh Na2

PbO

2

hay clorua ng (CuCl2

) t qu trnh lm sch bng clorua ng.12) Sn xut du m Vi qu trnh x laxit, nc thi c th cha axit, hp cht luhuynh v du nh tng. Qu trnh xl bng t st cng to ramt lng nh nc thi cha du hay nh tng du.

Nc thicng c th c cc dung mi mi x l. Nh vy, nc thi t mt s qutrnh sn xut v x l trong nhmy lc du c th cha du m, cc hydrocacbon,

phenol v cchp cht phenol, cc hp cht sunphua, cc cht rn ho tan v cccht hu ckhc dng BOD v COD.g- nh gi nh tnh nc thi lc dunh gi nhtnh dng nc thi v c tnh ca cc qu tnh lcdu c bn c th cho trong

bng 3.3..C nhiu kh khn khi xc nh lng cc cht thi khacvs nhauvi ttc cc thng s cn bit cho mi qu trnh c bn. Do vy,y ch l cc thng tinmang tnh cht nh tnh. Tuy nhin, ccthng tin ny cng c th c dng d


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bo nh lng cc chtthi.Lng v c tnh nc thi ca cc qu trnh khcnhau rt khcnhau. Nhn chung cc ngun ang g nc thi ch yu l nctho

bnh s tr, nc loi mui v chng ct du th, cc qutnhcracking xc tc vcracking nhit, tip sau lcc qu trnh x l bng dung mi, loi sp, lm khv lm ngt.Hai dng nc thi c ngha ln l nc chua(cha sunphua,luhun mecaptan v du) v nc kim s dng. Cc ngun ncchua c bnl phn lng ngng t t cc thp phn on khcnhau.Nc kim bt ngun tcc qu trnh fra kim(ra nguynliu, cc sn phm trung gian v cc sn phmcui cng). Ncny c trung ho bng axit, loi b sunphua cng nh luhunhmecaptan.Bng 3.3 nh gi nh tnh dng nc thi lc duKiu ph bin thng dng v mc phc tp ca cc qu tnhx l nc thi lcdu c xc nh c bn da vo lng chtv c tnh ca dng thi tng chkhng phi da vo h thngcc thit b hay qu trnh x l lc du. Tnh chnh xcca cc tiuchun nhim cng cao th vic x l nc thi phi c yu cuxem

xt di dng cc vn nhim c bitTrong bng trn, cc thng s c giithch nh sau:+ Lu lng dng thi: da vo tng lng nc s dng thchngct du th l phn xng s dng nc ln nht do th tchca cc thit b ngngt baromet v cc thit b loi mui l ln.Phn xng cracking xc tc v phnxng lm ngt, lm kh l phn xng s dng nc ln th hai. Qui m calng nc sdng b nh hng rt nhiu bi trnh cngngh ca cc qutrnhc dng. Trong cc nh my mi hn, vic gim mnhlng nc s dng cth t phn xng loi sp v cracking xctc, m c bn l tng lng nc ti sdng.+ Nhit : Loi mui ca du thk, c bit qu trnh tnh ingn gp tinhit thi ln cng nh qu trnh chng ct vcracking. Tng vic s duntgj ccthp lm mt ng vai tr quantrng trong vic gim tng ti nhit m cch chyu l gim lngnc thi ra ch khng nht thit phi gim nhit dng thi.Tinhit dng thi c th c nh hng bt li n vic x l v thuhi nc bi vtng nhit lm gim kh nng ho tan oxi v phi s dng lng oxi ln hn.C hai vn u lm gimkh nng iu khin ti trong thi ca dng kh.+

pH: pH ch ra nng ion hydro(H+

) trong nc thi. Tuy nhin,cc gi tr cc i ta thng quan st c khngphn nh ngdung lng ca cc cht thi hay nh hng cui cng ca n

lnngun nc thu hi. Phn ln nc thi lc du c tnh kim. Ccngun nckim c bn lnc tah ta cc qu tnh cracking (ccracking xt tc v crackingnhit) v nc thi t qu trnh loimui ca du th. Mt s qu trnh x l bng dung mi cng nggp lng chtkim ng k. Cc qu trnh x l bng hydro angngy cng tr ln quan trngcng ng gp lng nc thi csotnhkim nht nh. X l nc ni hi ca

phn xng sn xutin gp phn gim lng nc thi v bn c tnh kim.Cc


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qu trnh alkyl ho v polime ho dng cc cng ngh x laxit v c nhng vn v axit kh nghim trng. Nhn chung, ccdng thi lc du c pH khc nhau,nhng xt v tiu chun dngthi n khng phil vn ch yu. Khi pH nmngoi gii hnthng thng, vic phn phi hay san u nc thi kim( vthnhthong l nc thi axit) trc khithi n xung h thng cngrnh l bin

php m bo duy tr pH. Nhn chung, thtch lnca nc lm mt v nc ras ho tan axit mnh hoc cht thikim. Nh vy, pH s l vn quan trong khith tch nc lmmt gim xung.iu khin pH cng l vn quan trng xt vcc hot ng xl nc thi lc du. pH rt thp hoc rt cao c th gy rahoclm xu i qu tnh nh ho du trong h thng nc thi. pH canc thi cnh hng n cc qu trnh x l sinh hc nht l khix l sinhhc c s dngvi quy m ln hn. Do vy, n l yut quan trng nh gi hiu qu x l.+

Nhu cu oxi: s o nhu cu oxi sinh hc v ho hc l cchthng s cht lngnc rt c ngha. COD v BOD l ccthng s tiu chun c dng nh

gi cc nhu cu oxi hohc v sinh hc .Phn ln nc thi lc du u c nhucu oxi. Cc ngun c bnl cc hydrocacbon ho tan v cc hp cht sunphua. Dtr duth v sn phm cng nh cc hot ng phn phi sn phm lcc ngunng gp COD vBOD kh quan trngv phi dng rtnhiu thng v b cha vs ln tip xc n du v cc sn phml rt nhiu. Tuy nhin nc thi t c hotng ny l khng lintc. Cc qu trnh cracking v x l dung mi l cc ngunnggp BOD ln v thng xuyn.+ Hm lng phenol v cc hp cht phenol:Cc qu trnhcracking xc tc, chng ct phn on du th v x l sn phm lcc ngun ch yu ca cc hp cht phenol. Cracking xc tc tora cc hp cht

phenol bng cch phn hu cc hydrocacbon thma vng nh antraxen vphenanthren. Mt s qu tnh x l dungmi dng phenol lm dung mi v mc dn oc thu hi bngcc qu tnh thu hi nhng mt mt l khng trnh khi.Phenol vcc hp cht phenol, c bit khi clo ho, to ra vn mi v vtrongnc, ng thi chngcng c+ Hm lng sunphua: dng thi sunphua nhnchung bt ngun tloi mui du th, chng ct phn on du th vqutnhcracking. Cc hp cht sunphua tho lun y bao gm c cchp chtmecaptan. Cc hp cht sunphua gy cn tr cc hotng lc du. Chng c thc lo b bng nc kimhyr bngcc dung mi amin nh dietanolamin hoctn ti nh nc chuangng t trong cc qutnh x l v s c x l nh nc

chua.C qu trnh x l bng hydro c dng loi b cc hp chtsunphuatrong nguyn liu gp phn lm gim dng thi sunphua.Tuynhin, phn ln hpcht sunphua c loa b dng H2

Schng c thu hi hay t chy to SO2


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.+ Hm lng du: y l cht nhim ch yu ca nc thi ccnh my lc du.Khi du tn ti dng tdo, n to vt du loangtrn mt nc, c nhu mu scv bao ph ln cc vt rn. Cccht rn b ph du l vn rt phc tp v chngthng c trnglng ring trung bnh v rt kh loi b bng cc cng ngh

phntch trng lc truyn thng. Du v cht rn b ph du cng lvnd nghim trng i vi mi trng nc.Loi b du bng cc thit btch API hoccc thit b khc l bc xl s b cn tht trc khi x l sinh hc.Du c khnng ho tan h ch trong nc v do chng cngng gp mt lng nh vodng BOD v COD. Tuy nhin, dum v cc sn phm du m cha nhiuhydrocacbon c kh nngnn chng c th xm nhp vo nc sn phm. Dngnc rasn phm cng ng gp nhu cuBOD v COD.h- nh gi nhlng nc thi lc duVic nh lng cc cht thi l rt kh v cc nh my lcduthng khc nhau v quy m, trnh cng ngh, h thng x l,nguyn liu u vo, y ly v d mt nh my lc du cngsut khong

100000 thng/nag, so snh cc mc trnh cngngh, dng bao thng s BOD,phenol v sunphua so snh. Bac tnh ny, cng vi du, l c c tnh ch yucn x l. Ngita c th cn c vo cc gi tr ny la chn cc phng

phpx l thch hp. Vi cc nh my lc du khc, trc khi la chn phngphp x l nc thi cng cn xc nh s b cc thng sny.Bng 3.4. Lngcht thi v th tch nc thi ca mt s qutrnh c bn.Bng 3.5. Lng chtthi v th tch nc thi tnh cho 1 on vnguyn liu.Bng 3.6. Tng lng cht thi (k c cc ngun khc) sau thit btch API.Bng3.7. Tng lng cht thi (k c cc ngun khc) sau thit btch API tnh cho 1thng du.Bng 3.8. Tng lng cht thi ca cc qu trnh x l.Bng 3.9. D on lng nc thi v lng cht thi tnh theo 1nv sn

phm.Di y l lng cc cht nhim ch yu trong mt s dngthi lc du.1)

Nc thi loi mui( Nc thi t qu trnh loi mui)Dng thi ny trong cc nhmy lc du c th chimkhong5,7% th tch du th c ch bin(t 3.2-8.7%).

Nng cccht nhim ca mt s nh my lc du nh sau:+ Cc sunphua: t0-13mg/l, trung bnh 4.3mg/l, khong0.25kg/tn du th.+ Cc phenol:10-2415 0.9+ Du : 20-51616910.0+ BOD : 68-610 256 15+ COD(4h,KmnO4

) 124-470 29117+ pH: 7.2-9.1 8.22)

Nc ngng t chua

t hi nc b ngng t trong chngct v cracking). Nng cc cht nhimca mt s nhmy lc du nh sau:+ H2


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S: t 300-11000mg/l, trung bnh 4200mg/l.+ NH3

100----7000 3100+ Cc phenol 100-1000 420+ pH 7.5-9.5 8.5

3)

Nc ngng t cha phenol t cc qu trnh cracking: vimt snhm lc du,nng cc cht nhim nh sau:+ Cc sunphua: t 40-15600mg/l, trung bnh4500mg/l+ Cc phenol: 15-1400 350+ NH

3

; 86-6975 2000+ Du 3-100+ BOD 120-3040Ch rng, cc gi tr nng nych tng ng vi mt s nhmy lc du. Tuy nhin, vi cc nh my lc du nichung th yu l nhng thng s quan tm trong x l nc thi. Ngoi ra,ngita cn quan tm n lng cht rn l lng, hm lng cckim loi nng..i-

S thu gom nc thi x lS ch gm mt s phn xng c bn c thi

nc, cc qutrnh khc c thi nc cng c th b sung vo s ny.k- X lnc thi lc du ngay ti ngun thi.Phn tch cc cht thi lng cha ho cht vcc cht c mi ngayti ngun thi chng x l trc khi thi nc vo h thngthugom nc thi lc du c cho l bin php kinh t v hiu qunht gimthiu cc ho cht v cc cht c mi. Phn xngno l ngun gc ca cc chtthi phi c nghin cu cnhng s thay i cn thit c th trong qu trnhhot ng nhmgim cc cht thi. Trong mt s trwongf hp, nc thi t mtqutrnh x l c th c dng x l nc thi t cc ngunkhc. Cc dng thichnh c th c x l ringbit l: cc dngcha nh tng du trong nc,nc cha lu hunh, cn bn axitv nc thi c tnh kim s dng. nh gi tng th v tnh hiu qu ca cc hot ng x l tinh my trongvic gim nhim nc thi cn c cc thng tinchi tit v cc lu lng ncthi, v nng cc cht nhim ttt c cc phn xng ch bin lc du v cc

phn xng ph tr.vi cc thng tin nh vy c th xc nh c cc nh hngnhim thay th ca phn xng ny ch khng phi ca phnxng kia hocphici thin hot ng chung ca ton nh myhay l cc cng vic qun l.Ci thinhot ng chung ca ton nh my v cc cng vic qunl s gim lng cht thinhiu hn so vi ch thay i cc qutrnh sn xut. Dng cc cng ngh tin tins gim c ng klng nc thi.Cc phng php u khin x l ti nh

my quan trng bao gmcc qu trnh tch v thu hi, trung ho v oxi ho kim sdng, x l nc cng v kim sot nhit .2.2.2. Nc thi ho dua- Ccdng nc thi ch yuTrongcc nh my ho du, nc thi t cc qu trnh khcnhauc phn tch v thu hi trong cc hthng cng rnh ring bitngha l quah thng nc thi, cc knh nc ma v cc cngnc thi sinh hot. Cc dngnc thi thng gp trongnhmho du baogm:1)


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Nc thi cha du bao gm nc thi ring bit t cc nhmy sn xut hp chtthm (thm ho AP), nh my snxut olephin(OP), etylglylcol(EG),vinylclorua(VC)..2)

Nc thi x l t cc qu trnh alkyl ho benzen cha florua3)

Nc chua s dng cha sunphua t cc nh my sn xutolephin4)

Nc thi x l t phn xng polypropylen cha bt polmev cc kim loi nng5)

Cc dng xyanua long hay c t cc nh my sn xutacrynitril, si acrylic vacrylat.

6)

Nc thi x l cha vn caosu t nhm cao su polybutandien

7)Nc ma b nhim nng t cc phn xng x l, ph tr hay cc khu vc bcd.8)

Nc thi t cc thp lm mt9)

Nc thi sinh hot b- Cc c tnh c bn ca nc thi Nc thi t cc qutrnh nu trn c c tnh ring tu thuc voqu trnh v cng ngh x l. Mt sthng s c trong nc thiho du c cho trong bng sau:Bng 3.10. c tnhnc thi t nh my ho du.2.3. Cng ngh gim lng nc thi v gim nhim Nc x l v nc lm mt l cc ngun nc thi ch yu. Dovy, ngita tp trung nghin cu v s dng cc cng ngh lng nc thi v cc cht nhm ngy cng gim i.2.3.1. Trong lnh vc lm mtTrong lnh vc lm mt,ngi ta tm cch ci thin nc thi tcc thp lm mt. Mt s bin php thngdng la:+ S dng khng kh lm mt nhiu nht c th gim ti nhtcathp lm mt.

+ X l s b nc b sung vo thp lm mt bng phng phpmm ho bng vilnh, in phn haymm ho bng zeolit+ Lm mt nc lm mt bng khng khvo m hay thi titlnh+ Ti s dng cc dng thi lc du c x l nh l

nc bsung vo thp lm mt(cng c th dng lm mt nc ra haync cuho)+ S dng cc dng thi t cc ni hi p sut thp lm nc bsung vo thplm mt.+ Ti s dng cc dng thi lc du x l dng cho lm mt 1ln9nh lm mt cc bm, cc my nn, cc thit b ngng t bmt hay ngng t

baromet(gin tip v trc tip)+ S dng cc dng nc mm dng thi cathp lm mt lthp nht+ Thu gom vti s dng cc dng nc ma cc khuvckhng c qu trnh ch bin lm mt nc b sung vo thp lmmt.+ Ti s


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dng nc sc ra nha trao i ion ca thit b loikhong lm nc b sung+ Sdng bin php ozon ho x l nc lm mt nhm gimsto cn bn, hn chhay c ch n mn v gim dng thi tthp lm mt.2.3.2. Trong lnh vc ncx lTrong lnh vc nc x l c th p dng cc bin php sau:+ Ti s dng ccdng thi x l lm nc dp cho cc l gianhit loi cc.+ Gim thiu lnghi cho cc thit b tch sn ca thp chngct kh quyn+ Tun hon mt phndng thi t thit b loi mui lm nc rau vo+ S dng nc chua ctch lm nc ra loi mui+ Ti s dng nc ngng t t hi nc cho qutrnhtch trongthp chng ct d th cha du hoc dng phn lgn ngng tthi nc ca thp chng ct chn khng lm nc ra loa muihoc lm ncra phun ln cc thit b ngng t nh.+ Thu gom nc ra c bhm vo cc thit b lm mt trunggian cc my nnkh t bm ngc ln cc thit b ngng t nh cc thp phn on sn

phm ca qu trnh cracking xc tctng si.+ Khi ra sn phm, quay vng mt

phn nc ra ti im giaca thp phenol tip xc kiu m lm vic ngcchiu tngnng cht thi v gim yu cu nc sch (tng kh nngtruynkhi, gim lng nc)+ S dung nc chua c tch la nc ra

bm ngicchiu vi cc thit b ngng t trong chng ct du th v cchthit bx l bng hydro+ Ti sinh nc ra cc(loi cc), s dung dng thi x lhocnc chua c tch lm nc b sung ti nhnh ra cc(loicc)+ Gimthiu lng hi nc dng cho h thng bm ht dngdng hi nc thp chngct chn khng. Nh vy, ngi ta c gng ti u ho lng nc v hi ncsdng trong nh my gim thiu lng nc thi.3- X l nc thi lc hodu.3.1. Mc ch, tiu chun dng thi lc duX l nc thi nhm m bonc thi ra t cc tiu chun ncthi quy nh. C th cn c the tiu chunnc thi cng nghiphoc tiu chun nc thi lc du. Mi quc gia thng chthng tiu chun mi trng lc du v tiu chun nc thi lcdu ring.3.1.2.Mt s tiu chun nc thi lc duC nhiu loi vf cp tieu chun khc nhau.Vd tiu chun EPAcu M, c cc tiu chun cp A, B, C, D v E+ Cp A: cth p dng cho cc nh my lc du sn xutcc sn phm du m bng qutrnhchwng ct du th v reforming xctc (ch c chng ct du th vreforrimng xc tc)+ Cp B: c th dng cho nh my lc du c chng ct duth,cracking v cc a trnh sn xut khc nhng khng c sn xutdu nhn

+ Cp C: c th p dng cho nh my lc du c chng ct duth, cracking voho du nhng khng c sn xut du nhn+ Cp D: c th p dng cho nh mylc du c chng ctduth, cracking, cc qu trnh sn xut khc v sn xut dunhnnhng khng c ho du.+ Cp E: c th p dng cho nh my lc du cchng ct duth, cracking, cc qu trnh sn xut khc, sn xut du nhn vhodu.Vi mi cp tiu chun li c mt s quy nh ring nh quy nhBPT, BAT,BCT, NSPSBng 3.11: Tiu chun nc thi lc du ca M, Canada v


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tiuchun ph bin+ Quy nh BPT: cng ngh kim sot kh thi nht sn c , chottc cc cht nhim.+ Quy nh BAT: cng ngh sn c nht c th thc hint hiuqu kinht, bao gm sunphat, phenol, COD, NH3

, crm tng vcrom(IV).+ Quy nh BCT: cng ngh kim sot nhim ph binnht, baogm tng cht rn l lng (TSS), du v pH+ Quy nh NSPS: tiu chunthc hin cho cc ngun miDi y l mt s tiu chun nc thi lc du.Bng3.12: Tiu chun nc thi lc du ca n v quc tBng 3.13. So snh tiu chun n (MINAS) v quy nh NSPS Nc thi cacc nh my lc du cn p ng cc tiu chun c t ra, khng hc theo cctiu chun quc gia m cn theocc tiu chun khu vc v quc t. Cc nh mylc du mi xydng cng phi m bo cc tiu chun nc thi v phi cncvo cc tiu chun kht khe nht. Nc ma bo cha cht bn thi ra n cx l ring bit vinc thi sn xut s c cc tiu chun sau:

+ Du v m: 1.5mg/l, max+ Tng cacbon hu c: 110mg/l, max3.2. Phng phpx l nc thi lc du3.2.1. Phng php x la- Phn loiC nhiu cch phn loicc phng php x l khc nhau nhngngi ta thng phn chia theo c tnh vtheo cp x l+ Theo c tnh: c cc kiu x l nh c, ho, sinh hc+ Theo cpx l: c th chia thnh 3 cp x l loi b cc cht nhim trong nc thi lcdu l:- X l cp I: nh cc phng php phn tch trng lc- X li cp II: nhcc phng php trung ho, ng t vlng ho hc, sc kh ho tan- X l cp III:dng cc phng php ho, l v sinh hc nh b kh ho bn hot tnh, mnglc(tht b lc, git, oxi ho, thplm mt) b- Cc phng php x l thuntin cho vic nghin cu, cc phng php x l cchia thnh 5 kiu c cim chng: vt l, ho hc, sinh hc, cpIII v x l ti nh my.B1- Phng phpvt l(x l vt l) Nc thi lc du c th cha cc cht rn th, ni hay llng,du mChng cn c loi b trc khi x l ho hc v sinhhc. Cc qutrnh c bn, ph5 bin trong x l vt l lthnh(li) chn, lc sn, by du m,kt bng(ta bng), lng,lc ni(tuyn ni), kt tu khng dng cht ho hc, thm

bn hottnh hay cht pha ch.. Phng php x l ny c bn loi b ccvt liutr c th gy cn tr cc x l tip theo+ Thanh(li) chn: Mc ch ca lichn l loi b cc vt liuni c kch thc ln cng nh trnh s bm dnh trongthit b lcv gy cn tr qu trnh kh ho trong bn hot tnh. Chng c thlm

sch bng tay hay thit b c hc. Khi lm sch bng tay thvn tc gii hn cadng l khong 0.45m/giy+ B lc sn: B lc sn lo b cc loi sn nh ct,si ctrng lng ring ln hn vt liu huc l lng. Mc ch cavic ny l bo v cc thit b c hc v trnh lng ng trongng ng. Hai kiu

b lc s thwowngf dng l b lc sn dngchy ngang v b lc sn kh ho+Lng cp I: Mc ch l lgim hm lng cht rn l lng c thlng c trongnc thi. Ti y, nc thi c yn tnh, ccht c trng lng ring ln hn


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nc thi s lng xung vnhng cht c trng lng ring nh hn s ni ln tr.Khong50-60% cht rn l lng v khong 20-40% BOD( 20o

C) c thc loi b ti b lng c thit k ph hp. Thi gian lu li ph binl 90-150pht khi lu lng dng chy trung bnh. Trong1 ngy, 1m3

b lng c th x l 20-40m3

nc thi+ Phn tch du: Trong nc, du c th tn ti dng t do haynhtng. Cn loi b du t do trc khi ph nh tng dunc. Ngi ta thngc gng du t do ni trong cc b cthit k ph hp v sau n c ht

bng tay hay a quay. Vntc nng git du ctnh theo nh lut Stoke. C thdng nhiuloi thit b phn tch du khc nhau nh tht b tch API, CPI,DAF,TPS. Cc thit b tch trng lc c thit k c bn loi b du ni v cc cht

rn lng c. Hiu qu loi b du c thtch oc l 50-90% v cc cht rn llng l 10-85%. Cc tht btch trng lc cng loi b c BOD, COD v phenol.Cc loi b ny l kh ln(40-50%) tu thuc vo c tnh nc thi.Phenol c khnng ho tan trong du v nh vy c th cht ct nc thi v loi b cn vidu nh thit b tch.Hiu qu loi b du ca cc thit b tch trng lc chj nhhngln bi vic qun l nc thi ti nh my cng nh bi vic thitk v vnhnh ca bn thn thit b tch. Phn ln du c th tchoc trong h thng ncthi c th c lai b vi hiu sutcao nh thit b tch trng lc ny nhng chtlng dng ra(thayi t 20-150mgdu/l) s tt hn nhiunu kim sot ti ngunthic hiu qu v kim sot ti ngun thi l bin php ti thiuho lng duvo h thng cng rnh v tr u tin. Hn na,du dng nh tng v c bitdu bao ph ln cht rn l rtkh loi b bng cc thit b tch trng lc.Thit b tch API c th lm vic bnh thng m khng cn dngmt ho cht,cht ng t hay cht tr gp no. Du v m ctch t thit b ny chnh l duu s c thu hi v ti s dngtrong lc du. Gn y, cc thit b tch a mingi (TPS) hoccc thit b phn tch a nh cng c dng tch du t dorakhi nc thi. TPS hot ng tt hn cc thit b tch trng lc vn gimqung nng ca cc giit dutrc khi tin n b mt m chng kt hp lthnh lp du t do v c ht ra.Cc thit b tch trng lc l cc phng hnh

vung c trang bcc thit b co bn v ht du v thit k ca tht b da vovicloi b cc git du ng knh0.015 cm hay ln hn. Hiu quloi b du lokhong 98% Nh tng oc coi l hn hp ca hai cht lng khng ho tanvonhau, mt trong hai cht lng phn tn trong cht lng cn li dng cc git lng.Trong nc thi lc du cha c hai loi nhtng du trong nc v nc trongdu. Cc tc nhn php nhthng hp ph ln trn b mt ca cc ht nh tnglm gim bn ca n tng. Cc tc nhn l x phng, mui sunphat,


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axitsunphonic v axit naphtenic, hp cht amon dng t din, ete vcc este huc. Ngi ta thng dng cng ngh sc kh ho tan(DAF) loi bdu nhtwong. Cng ngh ny c th c dng ring bit hay kthp vi qu trnh ngt. S kt hp ny c th loi b 97% du,75% cht ran l lng, gim 80% BODv COD. S gim ny thayi theo c tnh ca dng thi.C ch c bn m nh nh tng du trong nc b ph bao ls trung ho in tchca git du bngcch t ra ht kt ta keot, mc ch ny c th t c bng cch iu chnh pHt 5-6ri sau so kt ta cc cht ph nh nh axit sunphonic, axitnaphtenic bngchc thm vi ti (Ca(OH)

2

cho n khi t pH t7.5-8.5Cng c th dng cc cht in phn cation phnh ca du. N c u th so vi cc phng php truyn thng. Cht hp ph

polypropylen cng c th dng ph nh. Cht hp ph ny lcht a du, k nc. Khi i qu nc thi n s hp ph du lntrn b mt ca

nCc cht ng tj khc nh sunphat st III , sunpht st II, cloruacanxi, cacbonatcanxi v vi ti c dng ph nh trong ccthait b tch du. Mt loi chtng t c th c hiu q cho nhmy lc du ny nhng c th khng c hiu qui vi nh mylc du khc. Do vy, phi cn c vo thc t nh my chncht ng t. Cc ht kt ta keo t c to ra trong qu trnh xl nh vyhp ph phn ln du v tu thuc vo nng du banu. Sau khi x l, dngthi c th cha hm lng du khong10mg/l hoc thm ch thp hnX l ncthi lc du bng qu tnh bay hi b gii hn kht khe bi v tr a l, kh hu vkh nng t ai. y r rng l phng php hp dn nhng ni cc quy tcdng thi cho phpTuyn ni khng c ho cht, ging nh qu trnh bay hi,khngc s dng rng ri trong x l nc thi lc du. Nhn chung,c th sosnh n vi thit b tch trng lc nhng n loi b dutt hn. Hn na, mtlng cc hp cht sunphua s c oxi honh oxi ho tan ca khng khThnhthong, cng cn tch NH3

nu pH c tnh kim, c th bng phng php sc kh. Hp ph bng cacbon cdng lmgim cc cht hu c. Thm thu ngc cng c th dng loi bcc cht hu c v v c.B2) Phng php ho hcSau khi loi b sn v cc chttri ni th tin hnh loi b cccht hu c ho tan v l lng. Cc qu trnh v

bin php quantrng lin quan n x l ho hc bao gm ng t, kt bng,lngho hc, tuyn ni c thm ho cht+ ng t, kt bng v lng ho hc:qu trnh sc kh ho tan cv khng c qu trnh kt bng c dng x lnwocs thi chm lng du thp. Vi iu kin ph hp, qu trnh sc kh cthgim lng du xung cn thp hn 10mg/l khi dng cc chtng t v cc chttr ng t. Tuy nhin, qu tnh sc kh ho tanyu cu nhiu k nng. S gim stthng xuyn v tiuth nng


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lng nhiu hn so vi cc thit b tch trng lc. Do vy ntc dng hnHiuq loi b cht nhim ca cc phng php ng t, lngv tuyn ni c dngho cht c nh gi l c mc ngangnhau. Cc phng php ho hc chiu qu hn cc thit b tchtrng lc, c bit khi loi b du nh tng. Ngoira, phng php ng t ho hc c th loih b nhiu BOD hn so vi tuynni

bng khng kh khng c ho cht. Tuyn ni khng khs hohc loi b c mtphn sunphua ho tan do chng b oxi ho vamoniac oc tch ra do khngkh.Sunphat nhm, vi, sunphat st khic dng c th cho kt qutt hn so vitrng hp ch dng lng n gin. Trong iu kinthun li c th gim 90% cccht l lng. X l ho hc cquan tm nhiu hn v.- C s gim v chi ph hocht( ho cht r hn)-Ngy cng hiu cch ng t r hn-N ci thin cc qutrnh x l bnKhi s dng cc bin php ny cn phi quan tm n thi giannnh, vn tc lng, c ch, khuy trn, khong pH ti u..;+ Kt ta sunphua:Hydroxyt natri(NaOH) khi c dng loi b cc hp cht lu hunh v phenol

c th to ra sunphua natri vcc sn phm khc theo mt s phn ng sau.(gphn ng vao)Nu nc kim s dng thi ra t qu trnh ra xng crackingbng kim th n s cha mt t sunphua natri Na2

S v cc hpcht lu hunh m ch yu l mecaptan v thiophenol. Trong mtsnh my lc du lng nc kim thi ra cha nng sunphuart cao th dngmui st kt ta cc hp cht sunphua c coil phng php hiu qu v kinht hn so vi dng phng phptrung ho sau khi tch bng khng kh hay hinc. Phng phpkt ta sunphua c bit tc dng i vi nc thi cha cchpcht sunphua v mecaptan v sau sunphua st cng kt ta (vitcng thc)

Nu dng clo v sunphat st III th s hiu qu hn. Cc phn ngthc hin ti utrong khong pH c tnh kim+ Lc ho hc: loi b cc cht l lng cn li. Phng php nyc th i kmhoc khng c ng t ho hc+ Tch kh ho hc(hp th ho hc): loi b cchp cht amon vH2

S+ Trao i ion: loi b photphat, nit v cht rn ho banB3) Phng php sinhhcX l sinh hc l bin php c bn cp I loi b cc cht nhim nh phenol,cn sunphuav BOD. N cng c dng loi b du khng thu hi c trong

x l cp II. Cc mm vikhun v cc cht dinh dng trongnc thi c du sthc yqut trnh phn hu sinh hc min l c oxi ho tan v thi giancnthitCc phng php sinh hc c dnh x l nc thi lc du bao gm bnhot tnh, thit b lc git, h sc kh v h oxi ho.Tt c cc phog php sinhhc ny u yu cu loi b du trckhi s dngTrong h thng x l sinh hc chc mt mi quan h duy nht vquan trng gia amoniac v BOD trong nc thi.Cc t chc huc pht trin oxi ho cc cht hu c cn khong 5 kg NH


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3

v 1kg photpho cho mi 100 kg BOD loi b. Cc cht dinh dng nyc thkhng phi thm vo h thng x l lc du v gn nh lunc amoniac v

photpho c mt trong nc thi.Tnh axit hoc tnh kim s thay i km theo spht trin sinhhc. S thay i ny c bn v dioxit cacbon(CO2

) to ra trong qutrnh oxi ho sinh hc v s to ra bicacbonat trong ncthiBOD ca du khong l tng i cao v khong 3-4mg O2

mi phn hu c 1mg hydrocacbon. Tu thuc v thnh phn hohc m nhucu oxi ca cc loi du t 3.1-3.5mg/mg du. So vimt s cht khc th gi trny ln hn nhiu: nh 1.07mg O2

/1mggluco, 1.18mg/1mg xellulo, 1.5-1.8mgO

2/1mg protein v 2.5-2.9mgO

2

/1mg du thc vt. Ngi ta thy rng, cc vi khun trongcc mng sinh hc vbn hot tnhc th loi b 84% du trongnc thi lc du.M v du c sckhng c i vi qu trnh phn hu ki kh vkhi c trong bn chng to ra s tchlu lp vng du d thatrong thit b phn hy lm tc cc l ca thit b lc v cn trovic s dng ccthit b lc ng thi cng ngn cn vic dng phn bn bn. Khi cc cht o cthi ln trong nc thi haycc dng thi x l chng thng to ra cc mngtrn b mt vlng ng cc di t ven b Bit lng du v m trong nc this gip ch cho vic khc phc cc kh khn trong vn hnh nh my, xc nhhiu qu canh my v u khin s thi cc cht ny vo dang thu hi.Bitlng m trong bn c th tr gip cho vic phn on mc phn hu vloi nc, ng thi ch ra s ph hp trong vic dng phn bn bn c bit. Tuthuc vo kiu cht oxi ho c dng,cc phng php sinh hc dng cc vi tchc hu c c tphp vo nhm phng php x l a kh( khi c mt cc phntr oxi t do) hoc nhm phng php x l k kh( kh khng c mtoxi t do)Tc phn hu ca cc vi sinh vt l hm quan trng ca b mt phn chia du nc.

B mt phn chia du nc cng ln th tc phn hu ca cc vi sinh vt cngnhanh. Ngi ta thy rng, vicloib du bng cc vi sinh vt xem ra lkh thivi s lng ccvi khun thchs hp( khang 51-61% du th c tn thu biccloi sinh vt trong thi gian 21 ngy).+ Phng php x l a kh: Cc phng

php x l a kh thngdng l thit b lc git, bn hot tnh, mng(b) oxi ho,cc hkh ho(sc kh), ao oxi ho.- Thit b lc git: Thit b ny a nc thtip xc vi vng pht trin sinh hc.Cc thit b ny c th gim hm lng du


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v phenol trong ncthi lc du- X l bn hot tnh: Cng ngh ny c dngcho cc qu tnhx l quy m ln. Bng su a ra s liu x l bn hot tnh 3nh my lc du:Bng 3.14: Gi tr trung bnh khi x l bn hot tnh c 3 nhmylc du.X l bn hot tnh c u im hn so vi thit b lc git:- Yu cu din tch nh-Khng c mi v s kh chu- t yu cu v p sut- Chi ph xy dng thp hn-Ao oxi ho: Phng php ny kh n gin, dng cc vi sinh vt loi b chtthi nhim du. Trong thi gian 30 ngy, lngsunphua gim t 15 xung 0mg/l,

phenol gim t 20 xung 7 mg/lv du gim t 15 xung 0mg/l, thi gian lu lyu t quan trngm bo tnh hiu qu ca ao oxi ho.- Cc b(h) kh ho(sckh): y thng l cc h chiu su 2.4-3.0m. Nc thi c sc kh bng khngkh khuch tn hay ccthit b sc khs b mt c hc.+ Phng php k kh:Thng dng cc h k kh. Cc h k kh x l nc thi c thit k trn c ss phn hu k kh vhot ng nh cc thit b phn hu m. Li ch chnh ca

cc hk kh l:- Lng cht hu c c th cao tnh trn 1 n v din tch cacch k kh- Chi ph u t thp v ch cn o p- Chi ph vn hnh thp v yucu dinh dng t hn nhiu so vix l a kh- Lng bn d tha b thi l tnhtB4) X l cp IIIX l dng nc thi cp III trong nh my lc du c giihn bi phng php dng cacbon hot tnh v qu trnh ozon ho.Mc ch c

bn ca x l cp III l loi b cc cht hu c chunhit kh phn hu v mtlng nh hp cht phenol cn dchuyn nhit t cc qu trnh x l sinh hc.Ccbon hot tnh vozon ho l cc phng php rt c hiu qu trong vic loa b cccht ny. Qutrnh clo ho khng c dng cho mc ch ny vs to ra cc cht clorophenolc mi v rt kh chB5) X l ti nh myCc qu trnh x l ch yu c th pdng cho cc dng thi ring bit hoc nhm cc dng thi trong nh my lc dul tch ncchua, trung ho v oxi ho kim thi, phn tch nc tho bnh,thu hi

bn du long v iu khin nhit .Cc thit b tch nc chua c thit k cbn loi b cc hpcht sunphua v c th lo b 85-99% cc hp cht ny. Nuthmaxit vo nc thi th s khng loi b c NH3

cng s ctch vi % thay i theo nhit v pH. Nu thm axit vo ncthith s khng loi b c NH

3. Nh vy, hiu qu loi b NH3

trong nc chua thay i t 0-95%. Tu thuc vo cc iu kinnh pH ca ncthi, nhit v p sut ring phn ca cht bn,cc hp cht phenol v hp chtxyanua c th c tch n 30%.BOD v COD cng c gim i v tchc phenol v cchp cht lu hunh thnh sunphat, qu trnh oxi ho khng


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cp dng cho kim cha phenol v phenol c ch qu trnh oxi ho. Nc thobnh khng c thi vo h thng cng ca nh my vdng thi ny c th tchln v l dng thi khng lin tc, nng urt cao s lm ri lon h thng xl nc thi lc du. Nc tho bnh c x l ring bit bng gia nhit, lng vlc.Du thu hi thng c chuyn ti h thng bn du.Kim sot nhit ngycng tr ln quan trng v tiu chun dngthi tr ln kht khe hn. gim tinhit m khng thay i qutnh sn xut thng ch nh vo vic tng lng ncti s dngtrong thp lm mt, cc im phu sng hoc cc thit b lm mtkhngkh ng c gn kh. Mt s nh my lc du dng ccthp lm mt nh l ccthit b x l sinh hc, c bit cho cccht thi cha phenol.Bn x l v bn tora trong qu trnh x l nc thi bng cc phng php sinh hc nhn chung clo nc v t b hocvt b. t bn phi c iu khin nghim ngt trnhgy nhim khng kh.1.2. Tnh hnh s dng nc trong cng nghip lc ho duTrong cng nghip lc

ho du, vn cha c thng k chnh xcchung v nhu cu nc s dng. Theo mts ti liu th lngnc dng ch bin 1 tn du th thng t 10-120m3

, tuthuc vo c tnh du th v h thng dy chuyn cng ngh.Tnh ring tronglnh vc ho du th to ra 1 tn sn phm cntrung bnh khong 50m3

nc. sn xut ra 1 lt xng cnkhong 10 lt nc, 1 tn t nhn to vtc cnkhong 800m3

1 tn than l sn phm ph ca qu trnh luyn cc cn khong11m3

ncHin nay, cc nh my lc du trn th gii hng nm ch binkhong 4 ttn du th (khong 25 t thng hay 800 t gallon). Nhvy, cc nh my lc dutrn th gii tiu th lng nc rt ln,hng t m3

nc trong 1 nm v chng cng to ra mt lng ncthi ng k. Lng nctiu th trong cc nh my lc c thchim trn 3% tng lng nc cng nghip.

Nc lm mt chimkhong 90% tng nhu cu nc s dng ca cc nh my lcdu.Khong trn 1/3 cc nh my lc du s dng li nc lm mt t 10 n 15

ln. Mt s t nh my lc du dng h thng lm mt1 ln. a s cc nh my lcdu dng h thng lm mt tunhon. H thng lm mt tun hon cn lng nclm mt nhiuhn khong 2 ln so vi h thng lm mt 1 ln nhng lng nc

b sung li t hn khong 25 ln. Tuy nhin, cc nh my lc dudng h thnglm mt tun hon c lng nc tiu th trn 1 tndu x l nhiu hn khong 24ln so vi cc nh my lc dudng h thng lm mt 1 ln.Vi cc nh my lc


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du tiu th nc t, trung bnh mt nh mylc du khng c phn xngcracking s dng khong 9-10m3

nc trn 1 tn du th, cn cc nh my lc du c phn xngcracking thngdng khong 12-13m3

nc trn 1 tn du th.Cc nh my lc du c cu to bi cc phn xng x l khcnhau th lngnc yu cu b sung cho cc phn xng cngthay i, trung bnh cn khong3m

3

nc cho 1 tn sn phm polime ho v alkyl ho v khong 0.4m3

nc cho 1 tn sn phm phn xng chng ct.Trong nh my lc du, phn

xng cung cp nc l phn xng ph tr khng th thiu. Cc nguyn ncca ring nh my lcdu p ng khong 95% cc nhu cu s dng nc. Ccngunnc mt cung cp khong 86% nhu cu nc s dng ,phncn lithng ly t nc ngm. Ch khong 1% nhu cu nc sdng c ly t hthng nc thi th nhng c x l li.Ch mt lng rt nh nc x l(nc cng nghip) c sdng li. C nh my lc du s dng lng nckim t qutrnh trung ho cc cht thi ca qu trnh alkyl ho thm vocc

bnh ngng t baromet ca thp chng ct chn khng. Tuynhin, s to nh tngln nhu v quy trnh b loi b. Cng cnh my lc du s dng cc dngnc thi cha sunphua tcc b phn tch trong cc qu trnh cracking iukhin nhit trong thit b cracking xc tc tn si bng cch bm cc dngthivo vng phn ng. Tuy nhin, c nhiu vn ny sinh tvic tn dng ny nhvn to gm, ng c xc tc, ti sinhxc tcC nhiu trng hp cc dngnc thi lc du sau khi x k cth du ti s dng nh vic dng nc thi cha

phenol hocnc ngng t ca qu trnh tch sunphua lm nc b sung vothitb kh mui trong du th. Ch mt s t cc nh my lc dus dng mt s ccphng php nhng ch mc gii hnno Ch khong 6% lng ncthu hi c dng lm nc x l. Nc x l ch chim khong 1,4% tng lngnc s dng. Crt t thng tin v vic ti s dng nc x l nhng vic ti

sdng c thc ngha. Lnh cc ti s dng nc c hiu qu nhtl tun honnc lm mt. Nh nu trn, trong lc du, nc ch yu c dng lmmt,mt lng nc tng i nh c dng lm nguyn liuni hi, cho x l, phc v sinh hot, phng chy v cc mc chkhc. Ngi tanhn thy rng, mt nh my lc du c cng sutkhong 50000 thngdu/ngy(khong 3 triu tn du/nm) to rahn 1 t Btu(hn 1 t KJ) trong 1 gi


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v khong 50% lng nhit c loi b bng nc. K n cc mc ch sdng nckhc v gi nh nhit nc lm mt tng 30o

F th ngi ta don rng nh my lc du s cn khong 160m3

/pht thuhi lng nhit . lng nc ny c th cung cp nhu cu ncsinhhot ca mt thnh ph (khong 230000m3

) trong thi giantng ng.Trong lc ho du, hi c ngng t thnh lng trongcc thit bngng t v cc thit b lm mt c dng h thp nhit casn

phm lng n nhit cho php bo qun an ton. Bnhthng, nc l cht lmmt trung gian thng c dng trongcc thit b ny. Tuy nhin, cc nh mylc ho du u tit kimc nhit v nc bng cch lm mt cc sn phm cnhit caonh ngun nguyn liu du th a vo v bng cc dng lng cnhit

thp hn khc. Nh vy, ngi ta thng dng cc bin php trao i nhit giacc sn phm v gia sn phm v nguynliu. Nhu cu nc ca cc nh my lcho du trc y l khng lnlm v vic s dng nc cng kh n gin, ncch cn cholm mt v to hi y cho cc bm hi. Trong ccnh mylcho du hin i th vic s dng nc thay i, tng i phc tp v chonhiu mc ch khc nhau.Chng ct chn khng du th v du th c tch

bt cc phn on nh(cn kh quyn) cn thit c dng trong hu htcc nhmy lc du v phng php chng li cun theo bng hinc dng bm phunhi nc l phng php c dng rng rinht to ra chn khng cho ccqu trnh chng phn onny. Khi dng cc bm phun hi nc, hi c dnqua mingvi phun to ra chn khng. Trong thp chng ct, hi nc bayhi v cun theo cc cu t v phn hi tch ra t thp chngct cn cngng t li tch nc v cc sn phm . Trongcc qu trnh x l, hi i ra nh c th c ngng t v thu hicc cht c gi trntrong cc thit b trao i nhit nh thit b traoi nhit loing chm v v ng. Cc cht c kh nng ngng tcn li phi c tch ra trckhi thi dng hi nh ra khngkh. Phng php thng dng l phun nctrc tip trong mtthit b gi l thit b ngng t baromet(thit b ngng t trctiaploi baromet). Cc cht hu c, du v hi nc ngng tu (chtlng ngng

t) c ho trn trong mt th tch nc lm mt ln.Hn hp v dung dch long c xu hng to thnh cc lo nhtng rt kh tch v thu hi.Trong cc nhmy lc ho du, cc thit b ngng t b mt(thit b ngng t gin tip) cng cth c dng thay th cc thit bngng t baromet. Cc thit b ngng t thng gm mt lotcc thit b trao i nhit loi ng chm v ng trong ccchtc kh nng ngng t c tch ra v nc c dng lm mtkhng tipxc trc tip vi cht ngng t. Trong nhiu trng hpcht lng ngng t c nng


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cao v c th c thu hi. ngoi rachng c th b t b hay x l ring bit.Nc lm mt khng bnhim bn du v cc cht hu c khc c th c ti sdng saukhi loi b bt nhit(h thp nhit ). Mc d thit b ngng t b mtgin tip c nhiu u im hn so vi thit b ngng ttrc tip baromet nhngchng c chi ph lp t cao nht, chi phvn hnh v bo dng cao hn v tuith thit b ngn hn. Ccvi phun hi nc ngng t b mt c dng trongnhiu nhmy lc du mi hn v chng ng vai trn quan trng trong vicgim

bt lng nc thi.Cng ngh gim nhu cu lm mt bng nc v do gimlngnc dng lm mt c mt s u im. cc vn kh cn,nc tr thnhqu gi th vic s dng cc thit b lm mt loing trao i nhit c gn l rtquan trng. Phng php lm mtny dng khng kh cng bc thi qua cc dyng trao i nhitc gn m nc lm mt s dng chy trong . Nhitctruyn t nc qua b mt cc ng trao i nhit ti dng khngkh theo

phng thc i lu v bc x. Li th ln nht ca phng php x l ny lnc

c chy trong mt h thng tunhon kn v nhu cu nc b sung l ti thiu.Mt li th khcna l nc c cht lng rt cao c th c dng v s n mngn nh khngc. Cc li ch gin tip khc ca vic gim lngnc tng cng l cc ng ngdn nc nh hn v cc chi phcho bm nc thp hn.Vic duy tr dng sn

phm n nh trong nh my lc du l iumong mun nhng i hi s iukhin cng nhc v thng rtkh. Qui trnh ph bin trong x l sn phm cyu cu l: tora sn phm nng t qu trnh x l c sn, lm mt chng v dtrchng cung cp nh l sn phm cui cng hay cc sn phm trung gian cho ccqu trnh x l tip theo. Trc khi ccsn phm trung gian c th c x l tip,n cn phi gia nhitli. Nu sdng my tnh v cc tin b cng ngh khc cthgim lng d tr trung gian v do gim lng yu cu gianhit v lm mt,tng yu cu nc lm mt ca nh my lc dus gim i. Nh vy, ti u hovn s dng nhit s lm gimlng nc yu cu.T c th thy rng, mcd tng lng sn phm du m angtng ln nhng lng nc ly vo gn nhkhng tng. Vic gimlu lng cc dng nc thi nh p dng qu trnh lm mthiuqu hn l c kh nng thc hin.Cc mc ch s dng nc khc nhau trongnh my lc ho duyu cu cc cht lng nc khc nhau. V d, nc mn cthc dng lm mt mt ln v nc kh khong cht lngcao c

dng cho cc ni hi cao p. Mc d, trong nh my lcho du, cht lng ncc xem l t quantrng hn khilng nc nhng nc c cht lng tt vnc mong mun.1.2.

Cung cp nc trong cng nghip lc ho duTrong nh my lc ho du, cc hthng cung cp nc khc nhauc to ra cung cp nc cho cc mc chkhc nhau. Hthng cung cp nc tun hon c cho l p ng cc nhu cusn


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xut trong nh my lc ho du . H thng ny c da trnvic s dng ncnhiu ln sau mt ln ly t ngun nc. Ncnng chy ra t cc thit b ngngt v cc thit b lm mt chynh trng lc hoc di p sut cao ti ccs n vcung cp nctun hon. , n chy qua cc thit b tch du tc thi v cch thng lm mt c bit nh b, b phun hoc thp lm mtnc. Thit b lmmt nc hiu qu nht l thp lm mt. Ccthp lm mt nc ca h thng tunhon c thit k c bit.Trong thit b , nc c cho chy xung b mtca m(gmng, chng ngi vt khc) dng mng mng hay git lng.Trongmt s thit k, cc vi phun c dng phun nc. Nc chy xung c lmmt bng gi t nhin ca khng kh bn ngoi(thp lm mt tun hon t nhin)hoc bng gi nhnto c to ra bi cc qut(thp lm mt gi c hc). Trongccthp gi c hc, nc c th c lm mt t 45-50o

C xung 25-28

oC. Nc c lm mt c thu gom li trong cc b cathp v c da trli cc ni tiu th bng cc bm p lc 0.3-0.4 MPa(khong 3-4at).Cc nh mylc du ln thng c vi h thng cung cp nctun hon:(1) cung cp cho cc thit b lin quan n x l dum v cc sn phm du m,nc ny trong trng hp khn cpt nh my m khng cn tch hn hp dum v cc sn phmdu m lng; (2) cung cp cho cc thit b ca phn xng ch bin kh v lm mt cc trcca bm v cc my nn, ncny khng c o nhim cc sn phm du m; (3) cung cpcho cc thit b ngng t hn hp baromet, nc sau khi s dngchamt lng ln cc sn phm du m, khi x l du chua thn cha H2

S v (4) cung cp cho cc thit b m t sp parafin v m c th xm nhpvo ncC th chia h thng tun hon nc thnh hai loi: h thng tunhongkhng lm bin cht nc v h thng tun hon lm bincht nc.H thng tunhon khng lm bin cht nc: Tun hon ngha lti s dng khng hn chcng mt lng nc cho trc chocng mt mc ch m khng hay t b nhim. Nc b sung sthay th lng nc mt mt khc nhau cc dng long(rg, mtmt do cun the) hoc bay hi trong trng hp bay hi thngxuyn xy

ra, Bnh thng, nc khng c thay i hay bincht khi thm cc ion bnngoi, cc kh ho tan hoc do s khuchtn ca cc cht rn v c v hu c trongsut qu trnh lm vic.Ch cc mui ban u tj li v tch lu do nc bay hi. Hai v din hnh ca hthng tun hon l qu trnh lm mt thit b trongh thng tun hon m(h) vh thng cp nc cho ni hi vivic quay tr li ca cc cht lng ngng t.T ltun hon nc c th cao v nng cc mui c kh nngho tan khc nhau b


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tng ln trong sut qu trnh bay hi. Do vy, phi tinh ch s b cc mui c khnng ho tan t trong nc bsung v dng nc chy ra trong h thng. Vic xcnh t snng C trong tun hon l c s tinh ch, vi C l t s gialngnc cung cp hoc lng nc b sung A v lng nctn tht nh l nc lnghay do dng thi ra D, ngha l C=A/D Nu gi E l lng bay hi , t s nng C c th c biu dinnh t s ca hm lng mun trong nc tun hon S vihmlng mun trong nc b sung s, ngha l C=S/s=A/D=(E+D)/D.T s tunhon R=Q/A vi Q l lu lng nc tun hon cng cth c dng xc nhmc tinh ch.Trong h thng lm mt tun hon h, C c th thay i t 1-6hoc thm ch 10. Trong thc t, t s ny c th c o bngcch so snh nng clo trong h thng vi nng clo ca nc b sung v khng c mun cloruano c to ra. Trong h thngcung cp nc cho ni hi, C cn cao hn nhiu,c th C=100.H thng tun hon lm bin cht nc: H thng tun hon ny lhthng tun hon m nc s dng trong h thng b nhim,cc cu t bn ngoi

c a vo nc b sung. S nhim c th:+ Xy ra cng vi qu trnh lmmt nh:-

Ra kh khi c mt HCl-

Ra kh khi c mt SO2

, kh hi ca ni hi-

Ra khkhi c mt HF, HCN, kh t cc l t-

Cn bn(cn thp) v dng cun theo cha du v cn du-

Ho tan NH

3

-

Ho tan hp cht lu hunh khi vn chuyn x v dp tttrong qu trnh cc ho+Xy ra ngoi qu trnh lm mt nh:-

Sc ra thit b lm tng lng mui ha tan-

Ra kh-

vn chuyn vt liu cha cc cht rn l lng hay cc mui Nu lng nhimc xem xt, mn v nhng cht bn trongnc b sung tr thnh yu tkhng quan trng th khi khngcn x l s b na. Nu ch cho php lng


34/42

nhim thp thnhng cht bn trong nc b sung phi tip tc c x l. Ngita c th dng mt s h thng ci thin cc iu kin x lnc nhim ti ccthit b cung cp nc tun hon. Tn thtnc trong cc h thng tun hon c

b li bng cch thmnc sch t b haycc ngun thi c tinh ch. Sau ncc x l bng photphat, axit vclo ngn chn s kt ta cacc muncanxi v magie t nc tun hon, s to cn bn trongthit b trao i nhit v s

pht trin ca c t chc hu c sinhhc trong nc. Nc sch c dng cung cp nguyn liu cho cc ni hi,chun b cc thuc th, ra mt s sn phmv cung cp li hthng nc tun hon. H thng nc sch bao gm cc thit

bly nc t ngun, cc trm bm nng cp 1, cp 2 v thnh thongc cp 3, cccu trc lc, cc thng ht v cc ng ng. Nc c th ung c dng cung cp cho sinh hc. Ngunnc ny l nc ngm hoc nc sng c x lc bit.H thng nc cu ho bao gm trm bm v ng ng chytheo ccng v phn phi ti ton b nh my lc du. ngng nc cu ho c

trang b vi nc my lp t theo tnhton thch hp nhng ti a 150m c 1 ci.Ti nh my lc hodu, ng ng cu ho c kt hp hoc l vi ng ngncsch dng cho sn xut hoc l vi ng ng nc sinh hot,thnh thong,cc h thng nc cu ho ring cng c lp t. Nc cung cp cho cu hoc d tr c bit, thng trong cc b ngm hay cc h cu ho. H thng cungcp nc tun hon,cung cp nc sch v cc dng thi c x l l ccngun dtr nc cho cu ho.1.3.

Ti s dng nc trong cng nghip lc duTrong nh my lc ha du, tun honnc c th khng phi lcch s dng nc c hiu qu kinh t nht, qu trnhny c thlm gim gi tr ca nc. Ti s dng nccng c th c sdng. ti sdngnc c hiu l dng vo hai hay nhiu mcch khc nhau m c th phn tch

bi cc giai on trung gianhay gia on x l.Trong ti s dng nc, mch chs dng sau thng yu cucht lng nc thp hn, thng khng qu bngmc ch thnht v do x l trong gian l khng cn thit. V d, nc cthc dng vo nhiu mc ch nh: Nc mt c th cdng trong h thnglm mt mt ln hay tun hon h sau lic dng tip ra hay lm schkh l .1.5. La chn ngun nc cho cng nghip lc ho du Ngoi vic nh

gi kinh t, c th cn c vo cc yu t sau la chn ngun nc:+ Tnh tnghp ca ngun nc vi mc ch s dng n: cn bng cacbonat, cng, nhit, nng yu cu v ccmc SO2

, SiO

2

, Ca


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2+

, Cl

-

, + Tnh tng hp ca nc vi cc kiu h thng x l c( ccqu trnhmng, trao i ion).Bng sau gi cho vic la chn cc ngun nc sn c tuthucvo mc ch s dng. Nc bin c th c dng m khng cngim mn ca n khi dng lm mt cc thit b ngng t vthu hi sn phm phngoi khi (thu hi du). Trong phn ln cctrng hp cn phi loi mui trckhi s dng.Bng 2.1- Cc mc ch s dng nc ch yu v cc ngun nclachn.M c c h s d n g N g u n n c c c h p nhn(sau khi x l) Nc dng x l,nc snxut c gi tr Nc c nng khong trung bnh Nc ung, ncging khoanhoc nc mt ch b nhimnh Nc loi khong dng

lmnguyn liu ni hi, loi mui Nc ging khoan hay nc mtch b nhim nh Nc lm mt trong h thng Nc mt c nng Cl-

thptun hon h dng cc thp lmmt Nc thi sau khi x l cp III Nc lm mttrong h thnglm mt mt ln cho cc thit bngng t v cc thit b trao inhit

Nc mt, nc bin, nc thi x l Nc ra kh hay ra sch sn phm, ncvn chuyn, tuc Nc mt hay nc thi x lcp II2.

Cc mc ch s dng nc ch yu2.1. Mc ch s dng nc ch yuTrongcng nghip, nc c dng vo nhiumc ch khcnhau. Phn ny ch cpn cc mc ch s dng nc c tnhcht cng nghip, khng k n nc dngcho mc ch sinh hotti nh my. C nhiu cch phn loi cc mc ch sdngnc.2.1.1. Phn loi theo tnh cht s dng(tnh cht trao i)Theo cch ny,c th chia nc s dng trong cng nghip thnhhai nhm chnh: nc tip xctrc tip v nc khng tip xctrc tip(Theo SIC: standard IndustrialClassifications)

a-

Nc tip xc trc tip: C th gm mt s loi sau:

1)Nc dng vn chuyn sn phm, nguyn liu hay cccht ho hc.2)

Nc ra v lm sch thit b, sn phm, ng ng,..(ncsc, ra v lm sch).3)

Nc lm dung mi ho tan.4)


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Nc pha long.5)

Nc dng gia nhit v lm mt tip xc trc tip(trao inhit trc tip).6)

Nc dng cho sn xut, x l.b-

Nc khng tip xc trc tip: C th gm mt s loi sau:1)

Nc lm nguyn liu cho ni hi2)

Nc dng gia nhit(trao i nhit gin tip).3)

Nc dng lm mt(trao i nhit gin tip).4)

Nc dng ngng t, lm mt(trao i nhit gin tip)2.1.2. Phn loi theo mc ch s dngTheo cch ny, c th chia thnh nhiu loikhc nhau, c th nhsau:a-

Nc to hi nc: dng lm nguyn liu cho nihi, my gi m khng kh,..b-

Nc dng trao i nhit, ngng t hi, lmmt cc cht lng v cht rnhay thit b, gia nhit,dng lm lu cht cho cc thit b ct gt..c-

Nc dng ra(lm sch) kh: nc ng vai tr nhdung mi hp th tp chttrong hn hpkh.d-

Nc dng sc, ra, lm sch v vn chuyn chtrn hay ion: dng trong nhiungnh cng nghip khcnhau nh lm sch than, qung, sn phm nng nghip,vnchuyn bt giy, x l b mt, nhng x l bmt..e-

Nc dng dp tt(quenching): dng dp tt la,nh sng, h thp nhit ..nh trong luyn cc, nghinthnh bt, lm x h thp nhit trong nhiu thit b

phn ng..

f-Nc dng duy trn p sut: a vo nhng khu vcgim p lm tng p sutnh qu trnh thu hi duth cp trong khai thc du..g-

Nc dng cung cp nng lng ng hc: cosch cn bn, g st.. trong dng nc l dng luth c nng lng cao.h-


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Nc dng cho sn xut v x l: Nc ng vai trnh mt thnh phn ca snphm hay tham gia voqu trnhsn xut to ra sn phm nh sn xut bia,ncgi kht v nhiu qu trnh x l vt l, ho hckhc nh chng ct,reforming..2.1.3. Phn loi theo mch ch s dngTheo cch ny c th chiathnh hai loi nh sau:a-

Nc dng cho mt mc ch1)

Nc dng trong cc h thng m(h) hoc b sung trc tip2)

Nc dng trong h thng tun hon, c hoc khng c s bin cht nc.b-

Nc c dng cho hai hay nhiu mc ch khc nhau nhtrong h thng ti sdng2.1.4. Phn loi theo cc ngnh cng nghipTheo cch ny c bao nhiu

ngnh cng nghip th c by nhiuloi nc, v d nh:a-

Nc lm nguyn liu ni hi: cng mm cng tt,khng cha nhiu nitrat hay cccht hu c trnhng cn hay n mn ni hib-

Nc cho cc thit b chng ct ru:tinh khit v mt,c th cha lng nh cctchcs hu c, t mui cloruanatri v clorua magiec-

Nc cho nh my giy:c mt st s gy hi, d vid-

Nc cho nh my ng: nu nc giu sunphat vcabonat v c bit l nitratth qu trnh kt tinh s rtkh thu nhiu mt ng, ng d b chy; ncchacc vi cht hu c c th gy phn hu ng..e-

Nc cho cc nh my nc gii kht: cha t vi vcacbonat magie..f-

Nc cho nh my ho cht: tu yu cu c th m yucu cht lng nc khcnhau.

g-

Nc cho nh my lc duh-

Nc cho nh my in, thp,xi mng..2.1.5- S phn loi mc dch s dngnc2.2. Mc ch s dng nc trong cng nghip lc ho duTrong cng nghip lcho du ch yu s dng vo mc ch sau1)


38/42

Nc dng lm mt, ngng t lm mt2)

Nc dng sc ra v lm sch3)

Nc dng lm nguyn liu ni hi4)

Nc dng x l5)

Nc dng phng chy cha chy6)

Nc dng cho sinh hot v cho cc mc ch khcTrong nc dng lmmt chim khong 90-92%, nc dng ra du, sn phm du, thit b v thngcha chim khong5%; nc dng x l chim khong 1.4%(0.1-1m3

/tn du xl); nc dng cho cc mc ch cn li chim khong 1.6-3.6%Trongho du, nhn chung nc cng c dng cho cc mc chtrn. Cht lng ncyu cu tu thuc vo tng nh my. Rtkh lit k yu cu cht lng nc cacc nh my ho du ny.S d n g L m m t Hthng x l trongngng ph3.2.2. - Chn cc phng php x la- Lng cht thi v phng php mt snh my lc duC nhiu phng php x l nc thi lc du nh trnh by trn. Mi phng php c u im ring v chng thng c sdng kt hp.tu theo c tnh nc thi v tiu chun nc thim ngi ta chn cc phng

php x l thch hp chi ph thpnhng vn t hiu qu cao.Cc phng phpph bin thng dng x l nc thi lc dul phn tch trng lc, kt bng,lc ni v xu l sinh hcDi y l mt v d la chn phng php x l khi

bit lngcht thi.Khi s dng cc phng php tch trng lc, kt bng, lc nivx l sinh hc c th gim ng k lng cht thi lc du. Cn cvo tnh hnhc th c th kt hp thm cc bin php x l khc.c-

Mc s dng cc phng php khc nhau Nh vy, mi nh my lc du cths dng cc h thng phng php v thit b x l nc thi khc nhau. Tt c

ccnh my lc du u dng mt s loi phn tch trng lc loi b du c thtch c. Cc phng php v thit b khcc s dng cc mc khcnhau. Di dy lbng mc s dng cc phng php trong mt s nh my lcdu c nghin cu. Mc s dng cc phng php ny c ththay i theothi gian cng nh s lng nh my lc du.Thiu, t bao gm t ti uc, lt ni hi v cc thit bt ring khc, ch dng khi c tch v bay hi. C th90-100%nh my yu cu dng cc phng php x l sinh hc cp II.


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c-

Hiu qu x l nc thi ca mt s phng phpTng kt hiu qu cc qu trnhx l nc thi trong loi b cccht nhim lc du c bn c cho trong bngdi yy. thun tin cho vic nghin cu, cc phng php x l c spxptheo c im chung. Trong bng cng cha mt thng sl u vo x l c khnng nht (v) (DPPI: Most probable

process influent) ch ra kiu v/ hoc quy m ca trc tinc yu cu tndng c hiu qu nht cc phng php xl tring bit xem xt.Bn cnh tnhhiu qu loi b cc cht nhim, bng tng ktcng cha cc thng tin nh tnhv s nh hng ca cc qutrnh x l khc nhau ln 3 c tnh nhim quantrng chung l pH, c v nhit . Khong hiu qu loi b v cc nhhngnh tnh da trn cc s liu sn c t cc nh my lcdu thc t.Bng 3.17. Hiuqu x l nc thi lc du da trn cht lngdng ra (%)Cn ch rng, BODv COD c loi b nh bng trn nh thit b tch trng lc khng bao gm

BOD v COD ng gp vodu c kh nng tch thc t c loi b. Nu kc nhnglng thc s to ra hiu qu loi b cht hu c cao khngthc t trivi lng chtbn thc t phn tn trong nc thi.Bng trn ch ra rng bn hottnh v cacbon hot tnh l cc phng php x l sinhhc hiu qu nht loi bcc cht huc. Hiu qu loi b BOD l 70-95%, COD t 30-70, phenolvxyanua l 65-99%. Hiu qu loi b cc cht rn l lng l ttngoi tr trnghp nng cc cht rn ra khi h sc kh caohn trong nc thi u vo.Diy (bng 3.18) l kt qu x l nc thi lc du ca mt s phng php x lkhi nng cht thi khc nhau.3.2.3- X l dng nc thi c bitKhi cn x lcc dng nc thi c bit nh nc thi cha nhiudu, phenol, HF, nc chua,nc kim, H2

SO

4

, kim loi ngita c th dng cc h thng x l nc thi ring bit gimnng cc cht cn x l xung gii hn chophp trc khi a vo hthng x l nc thi chung ton nh my. Sau y l mt s phng php v hthng x l.a-Loi b hp cht phenol: c th dng nhiu h thng x l khcnhaunh h thng x l lng-khng kh, h thng x l Esso,Mobil, Petrolite, Standar

Oil b- Loi HF: Dng cc thit b loi flo cha hp cht nhm(Al),vi, thuAlF, CaF

2c- Loi sunphua, amon(H2

S, NH

3


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): c th dng h thng oxi hokhng kh dng dng hi nc, dng h thng x lUniversal,Clauss, cc thp lm ngt..d- Loi kim: c th dng h thng caStandard Oil, MobilBng 3.18. Kt qu x l nc thi lc du ca mt s

phng php x l3.3. H thng x l nc thi lc du3.3.1. Mt s thit b vthng s x lTrong x l nc thi lc du, h thng x l gm nhiu h, b xlkt hp vi mt s h thng thit b x l. Phn ny gii thiumt s h thng thit

b phn tch nh API, CPI(TPI), DAF.a-

H thng phn tch APIb-

H thng phn tch CPI-TPIc-

H thng phn tch DAFd-

H thng x l a quay sinh hc RBCKhi quay, a quay c mng sinh hc vatip xc vi ncthi, va tip xc vi khng kh nn cht thi hu c nhanh b

phn hu hn. a quay RBC c th t ngang hay ng.3.3.2. Mt s s hthng x l nc thi lc duH thng x l nc thi lc du thay i tu theokiu v kchthc nh my lc du cng nh c tnh v h thng thu gomncthi. Di y l mt s s h thng x l nc thithng dng ti cc nhmy lc du

+ Nc thi cha du(nc chua, nc lm mt): c lu lngln v rt khcnhau, c cha vo b cha ri c x l loi bdu bng lc hay tuyn ni(lcni). Tu theo nng BOD, phenol, m chng c th c x ltheo cc

phng php hohc hay sinh hc. X l cp III l cn thit loi b huynphcng nh cc cht nhim d tha.+ Nc x l v nc tho bnh: c thcha nhiu mui, nhtng v cc cht nhim khc nh phenol, sunphua.. cx l bng oxi ho s b ri loi b du bng kt bng, tuyn ni v xl sinhhc..S h thng x l nc thi lc du cng c th nh hnh sau c c

h thng x l hiu qu nc thi pht sinh trong nhmy lc du th vn rtquan trng l chia tch cc dng ncthi c nng cao x l. Chia tch ccdng nc thi thnglm n gin ho cc vn x l cc dng thi c linquan. Ccx l nh vy thng l gii php kinh t hn so vi trng hpnc thic thi trc tip vo h thng cng rnh nh my lcdu.X l ti ngun cnggip ch th hi cc sn phm ph t dngnc thi m s khng kinh t khi thuhi t cc dng thi ckt hp li. X l ti ngun thi khng ch hu ch i


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vi vic thuhi cc sn phm ph m cn c tch dng chun b cc dng ncthicho cc qu trnh x l tip theo. V d, nc chua v nckim thi mun c xl sinh hc phi qua x l loi b cchp cht sunphua v mecaptan trc vchng c vi cc vi chthu c c mt trong cc thit b x l sinh hc. Chia tchcc dngnc thi tng i sach, nh nc lm mt, s gip ch cho vicgimtng lng thi cn x l v nc lm mt chim lng khln trong nc thi.Ccdng nc thi cn x l cp II l cc dng nc thi chadu, nc chua v nckim thi. Cc dng thi ny c th cx l mt vi kiu ca h thng x l cpII. Thnh thong, ngita kt hp vi cc thit b x l sinh hc ch khng s dngringt bin php x l nc thi lc du. Thit b lc git c dng gimti a cc cht hu c trc khi dng thi c x l ccdng nc thi v cc thp lm mt thnh thong c dng nhcc thit b x lsinh hc cho cc dng thi x l c bit (nccng ngh, nc x l).Dng ra th thng x l cp II c th c x l su hn na loi b cc cht hu c, cc

cht to mi, v, mu sc v cc chtv c ho tan. Phng php x l oxi ho bngozon c bit c ch loi b cc hp cht phenol t cc dng nc thi du m.

Nrt quan trng khi dng nc thi t nh my lc du c thivo ngun cungcp nc.Trao i ion c th c dng loi cc cht v c t nc thinhngkhng chc phng php x l cht lng cao nh vy licn thit cho nc thilc du. Trong x l nc thi, bn v nhtng bn du c to ra v chng cnx l. Cc cht c to rat cc qu trnh ny c chn hoc thiu t.C mt sdng nc thi khng yu cu x l ko di qua nhiugiai on x l. Nc lmmt nhn chung l tng i sch hoc lc thi trc tip ti h thng thu gomnc hoc l (nu chadu) th c x l bng tch trng lc trc khi thi. Cccht xctc dng thng khng c thi xung h thng cng rnhnc thi.Chng c th c ti sinh hay chn xung t.C mt vi yu t c th nhhng n hiu qu x l ca cc qutrnh khc nhau. Nc thi cha du s khngc trn vi ccnc thi x l cha cc ho cht c khuynh hng to nh viduv lm gim hiu qu tch trng lc. Lng ln du c xu hng ph ln bmt vi sinh hc cc thit b lc git v lm gim qutrnh trao i. Trong bnhot tnh, du lm cho bn ni ln v mttheo dng nc thi.Trong tch ncchua, pH l quan trng khi tch cc hp chtsunphua v amoniac. Tch bng kht lm cho nc thi c tnhaxit v NH

3, khng th loi b c. Trong tch bng hi nc th Nh3

c th loi b v pH khng thp.Chi ph ca x l cp II s thay i tu thuc vocc thit b cs dng trong x l cp II. Dng bn hot tnh l r hn khixydng nhng chi ph vn hnh s cao, thit bh lc git c pdng cho phnln cc nh my lc c th c chi ph u t cao


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nhng chi ph vn hnh thp hn. B x l ch kinh t khi t r vc sn nhng chiph vn hnh li rt thp so vi bn hot tnh vthit b lc git. X l nc thitrong thp lm mt c th gim chi ph nc b sung.3.3.3. Mt s s h thngx l nc thi ti nh my lc dua- H thng x l oxi ho s b cc hp chtsunphua t nc thiy l h thng oxi ho s b ri loi b du bng kt bng,tuynni hay x l sinh hc, x l nc x l v nc tho bnh cnhiu mui,nh tng hay cc cht nhim khc. b- H thngx l nc thi ti nh my lcdu Finaneste(B)y l s h thng x l nc thi c tuyn ni phn nhnhx l nc ra t thit b lc v nc loi mui nh my lc duFinaneste,cng sut 1000m3

/h. Quy trnh x l ny kt hp hai phng phpvt l v ho hc, kt hp lcnhanh nc cha duv tuyn ni bng khng kh ho tan, thng dng x lhai loinc thi co lu lng nh hn:

-Nc thi t vic ra thit b lc-

Nc nh ho t thit b loi mui v cc qu trnh x l khcd-

H thng x l nc thi nh my3.4. Thi nc thi lc du xung h thng ncthi sinh hotCh c khong vi % (1-2%) nc thi x l t cc nh my lcduc thi ti he3 thng nc thi sinh hot. L do ch yu lgn nh tt c ccquy nh thi uc quy nh cm thi du, chtd chy v vt liu gy n. Ncthi cha du thng bn vo hthng nc thi, nh hng n thu lc dngchy v nguy himchy n.Tuy nhin, nc thi lc du v nc thi sinh hot cth c xl cng nhau nhng u tin phi nh gi xem nc thi lc duc cn

phi x l s b hay khng. Thng thng, nc thi lcdu cn phi x l s btrc khi x l chung

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