cÁc cÔng nghỆ xỬ lÝ h2s vÀ voc

8/3/2019 CC CNG NGH X L H2S V VOC

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CC CNG NGH X L H2S V VOC (VOLATILEORGANIC COMPOUNDS) TRONG KH THI

Ging vin : Ts. Phm Xun NiNhm thc hin : 1.Nguyn Hu Dng

2. Nguyn Xun Khu

3. L Th Thy Dng4. Nguyn nh Chnh5. Nguyn Vn Cng


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TNG QUAN1.Ngun gc , l tnh2.Tc hi ca H2S3. Cc phng php x l :- x l bng mui cacbonat- x l bng NaOH- x l bng amoniac- x l bng natrithioasenat- x l bng than hot tnh- x l bng oxit st (Fe2O3)

4. Nhn xt , nh gi


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1 . Ngun gc , l tnh :

a . Ngun gcTrong t nhin :C trong nc sui, kh ni la, thot ra t protein phn hy .

Trong cng nghip :Dihydro sufua l loi kh ch yu ta ra trong qu trnh luyn cc t than, qu trnh lc du, qu trnh sn xut kh cng nghip, dihydro sufuacn l mt trong nhng thnh phn t kh t thin nhin. Ngoi ra,trong mt s ngnh cng nghip khc nh ch bin xenlulozo, si nhnto, nu bt giy, nu thuc nhum, x l nc thi, lng kh dihydrosufua ta ra cng ng k.

b. L tnh

- iu kin thng H2S l kh khng mu, mi trng thi, rt c,d=34/29=1,17 nng hn khng kh.

-Nhit nng chy -85,5oC, nhit si l -61,8oC.- trng thi lng cng phn li nh nc nhng mc yu hn.

- Hirsunfua t tan trong nc 2,5(l) H2S tan trong 1(l) nc


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2. Tc hi ca H2S- nng thp, H2S c kch thch ln mt v ng h hp.- Ht th lng ln hn hp kh H2S, mercaptan, ammoniac gy thiu

oxy t ngt, c th dn n t vong do ngt.- Du hiu nhim c cp tnh: bun nn, ri lon tiu ha, tiu chy, mi

hng kh v c mi hi, mt c biu hin ph mi, vim kt mc nhncu, tit dch m v gim th lc.

- Sunfua c to thnh xm nhp h tun hon tc ng n cc vngcm gic mch, vng sinh phn x ca cc thn kinh ng mchcnh.

- Thng xuyn tip xc vi H2S nng di mc gy c cp tnh

c th gy nhim c mn tnh. Cc triu chng c th l: suy nhc,ri lon h thn kinh, h tiu ha, tnh kh tht thng, kh tp trung,mt ng, vim ph qun mn tnh


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3.Cc phng php x l :a.X l H2S bng natricacbonat, amonicacbonat hoc kali photphat-Qu trnh x l H2S bng Na2CO3 c da trn c s cc phn ng sau:

H2S + Na2CO3 = NaHS + NaHCO3

-Tip theo l phn ng thu hi lu hunh ca Natri vanadat (NaVO3

)

2 NaHS + H2S + 4NaVO3 + O2 = Na2V4O9 +NaOH + 3S

- hon nguyn vanadat ngi ta dng cht xc tc ADA (natri amonivanadat v disunfonat)

Na2V4O9 + 2 NaOH + 2ADA = 4NaVO3 + 2ADAS phn ng nh sau :

Trong :1.thp hp th.2.thp gii hp th.3.qut.4.sy nng khng kh.5.iu chnh nc dung dch6.iu chnh lu lng dung dch ti.


7/17 S h thng x l H2S bng Na2CO3


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Ngoi ra, ngi ta cn c th dng amoni cacbonat v kali cacbonat lmdung dch hp th i vi kh H2S.

Vi amin cacbonat, phn ng xy ra nh sau:

(NH4)2CO3 + H2S = (NH4)2S +H2O + CO2

Amomi sunfua (NH4)2S thu c trong dung dch ra khi thp hp th s

c phn hy thnh NH3 v H2S. Dung dch NH3quay tr li chutrnh kt hp vi CO2 v H2O c trong kh thi to thnh amincacbonat v phn ng trn tip tc xy ra theo s h thng x l khH2S bng amoni cacbonat.


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S h thng x l H2S bng amoni cacbonatTrong :1.thp hp th.2. thp oxi ha.

3. thng phn li.

4. thng cha lu hunh.

5. thng ra.6. my lc li tm.


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b. Cng ngh x l H2S bng NaOH

-C s ca phng php ny l kh H2S kt hp vi NaOH theo phn ng

sau y:H2S + NaOH = Na2S + 2H2O

Na2S + H2S = 2NaHS

Na2S + H2O = NaHS + NaOH

-Song song vi phn ng trn, NaOH tc dng vi CO2CO2 + NaOH = NaHCO3

NaHCO3 + NaOH = Na2CO3 +H2O

-Ngoi ra phn ng kh H2S trong dung dch cn xy ra trong qu trnh

oxi ha natri sunfua thu c t phn ng (6) to thnh natri hydrosunfua v hyposunfit.Na2S +H2O = NaHS + NaOH

2NaHS + 2O2 = Na2S2O3 + H2O

-V mt bo v mi trng , cc phn ng ph l c li v chng gp phngim nh khu x l dung dch dng xong trc khi thi ra h thng

thot nc.


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S h thng x l H2S bng NaOHTrong 1. thp hp th

2. thng cha dung dch3.thng x l dung dch x dng trc khi thi ra ngoi

4. bnh cha dung dch mi ( xt hoc sa vi )5. bnh cha vi clorua

6. bm.


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c. X l H2S bng amoniac :

Dung dch amoniac kh H2S trong kh thi l qu trnh khn gin v c p dng rng ri . Trong thp hp th ,H2S trong kh thi tip xc vi dung dch amoniac vchng kt hp vi nhau theo phn ng :

NH3 + H2S = (NH4)2S

nhit v p sut thch hp amoniac sunfua (NH4)2S

phn gii thnh NH3 v H2S . amoniac quay li quy trnhlm vic , cn H2S c a sang cng on iu ch axithoc lu hunh n cht .


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S h thng x l H2S bng amoniacTrong :

1 . thp hp th2, 3 . thng cha

4. thit b lm ngui

5. b mt trao i nhit6. thp ct kh H2S


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d. X l H2S bng dung dch natri thioasenat

Na4As2S5O2

- Phn ng hp th kh H2S bng dung dch natri thioasenat xy ra nhsau :

- H2S + Na4As2S5O2 = Na4As2S5O + H2O

-Tip theo , natri thioasenat c hon nguyn theo phn ng :2Na4As2S6O + O2 = 2Na4As2S5O2 + 2S

-Hai phn ng trn xy ra rt nhanh v l cc phn ng ch yu trong huht cc iu kin vn hnh .

-Trng hp khi nng ban u ca H2S trong kh thi rt cao hoc thigian tip xc gia kh H2S v dung dch hp ph ko di th cc phnng ph chm hn sau y c th xy ra :

Na4As2S5O2 + H2S = Na4As2O7 + H2O

Na4As2S7 + O2 = Na4As2S6O + 2S

-Dung dch hp ph natri thioasenat c chun b bng cch ha tanAs2O3 v natricabonat Na2CO3trong nc vi t l 1:2 . Trong dungdch s c natro cacbonat , v bicacbonat , natri asenit , cc hp cht

trn s phn ng xem k vi H2S v oxy to thnh natri thiosenatNa4As2S502 .


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S h thng x l H2S bng natri thioasenatTrong :

1. thp hp th2. bm

3. thit b lm nng dung dch4. thp oxy ha

5. thng phn ly lu hunh6. thng lng lu hunh


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e. X l kh H2S bng cht hp th oxit st Fe

2O

3-y l phng php c in nht c da trn c s cc phn ng sau :

Fe2O3 + 3 H2S = Fe2S3 + 3H2O

2Fe2S3 + 3 O2 = 2Fe2O3 + 6S

- Sau khi bo ha H2S oxit st c hon nguyn bng khng kh (cp oxy) thulu hunh.

-Tc phn ng hp th H2S ca oxit st c hon nguyn bng khng kh(cp oxy) thu lu hunh.-Tc phn ng ph thuc vo mc tip xc gia kh v b mt vt liu hp

th. Do nng cao tc phn ng, rng ca vt liu hp th phi ln.Thng rng ca oxit st khng nh hn 50%.

-iu kin tt nht cho qu trnh hp th kh H2S bng oxit st l nhit nmtrong khong 28 30oC v m, ca vt liu hp th khong 30%.

- hon nguyn c th p dng cc phng php khc nhau: +oxy ha nguyn liu hp th bng oxy khng kh.+Thi hn hp hp kh c cha 22 30% oxy qua lp vt liu hp th. Nhit

hon nguyn 600800oC.-Hon nguyn lin tc khi vt liu hp th bng cch b sung vo dng kh cn

x l 1 th tch khng kh vi tnh ton sao cho lng oxy trong trong hn hp

kh gp 1,5 ln lng oxy l thuyt cn cho qu trnh oxy ha. Nh vy qutrnh hon nguyn s xy ra song song vi qu trnh hp th


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