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7/24/2019 Bi gng cng ngh mng

1/13

KThut Mng vng Dng

Bi 4: M hnh ha qu trnh chuyn khitrn mng

Ging vin: Nguyn Minh Tn

Bmn QT-TB CN Ha hc & Thc phm

Trngi hc Bch khoa H [email protected]

Vn chuyn vt cht trn bmt mng

Cc hiung gimng lc qu trnhTrlc cp khi cc b

Dung dch vo Nc trong

Phn cc nngpha dungdch vo

Lp

hot

ng

Lp

rng

Phn ccnngphanc trong

-Phn cc nngtrong lpbin pha dch vo(v phn ccnhittrong qu trnh thm bcv thm kh)

- Phn bnngtrong lp dcamngo pha/mng Composit

-Tn tht p sut ca dng thm

qua lp- Phn cc nngtrong lp binca pha nc trong


2/13

Vn chuyn vt cht trn bmt mngCc hiung gimng lc qu trnh

Phn cc nngtrong lp bin pha dch vo

Dng (khuych tn, i lu, chnh) trong lp bin pha dch vo

Phn cc nngpha dch vo

Mng


Cc hiung gimng lc qu trnhPhn cc nngtrong lp bin pha dch vo

(1) Qu trnh chuyn cht phthuc vo mng

- Xy ra trong cc qu trnh phn tch cc cht lng tan ln tun theo nguyn lHatan Khuych tn

- Dng nc lc nh

- Trlc ca mngng vai tr quan trng

- Dng nc lc chunh hng ca hin tng phn cc nng

(2) Qu trnh chuyn cht phthuc lp cn- Xy ra trong qu trnh Siu lc (UF) v Vi lc (MF)- Dng nc lc ln hn- Hskhuych tn ca cc phn tbmng gili nhhn- Cc cu tbgili trn mng lin kt vi nhau to thnh lp

cn/cake layer- Trlc ca mng nhhn trlc ca lp cn


3/13


Cc hiung gimng lc qu trnh

Phn cc nngtrong lp bin pha dch vo(1) Qu trnh chuyn cht phthuc vo mng

Gii thittnh ton nngca cc cu ttrn bmt mng:- Qu trnht cn bng- Qu tnh khuych tn tun theonh lut Fick- Khng xy ra bini ha hc- Gradient nngtheo hng song song vi mng nhhn

Gradient nngvung gc vi mng

Cn bng vt liui vi cu tj bn pha dch vo:

( )

= y

w

Dymwy

j

ijFyGesj &0

Dngi luDng khuych tn



constmym PGes == && )( constmym PijGesij == ,, )( &&

Phn cc nngtrong lp bin pha dch vo

Tch phn phng trnh cn bng vt liu trn kt hp vi:

hay

Cng viiu kin bin:

2:0 jj wwy ==

1: jjF wwy ==

Phn bnng khong khng gian bn trn mng:

=

=

F

y ijF

P

jj

jj

D

dym

ww

ww

0

*

2

*

1exp &

i vi mng loing (htatr)

=

i

Fi

R

R ijF

MP

jj

jj

Dr

drRm

ww

ww

&exp*

2

*1

Nngkhi lng cutj trong dng lc ti v

trang kho st

Dng lc


4/13


Cc hiung gimng lc qu trnhPhn cc nngtrong lp bin pha dch vo

Kt qutch phn l phng trnh m tphn cc nngtrong lp bin pha dch vo

=

=

FF

P

ijF

FP

jj

jj

k

m

D

m

ww

ww

&&expexp

*

2

*

1

i vi mng loing (htatr)

ijF

MP

D

Rm

Fi

ij

Fi

i

ijF

MP

jj

jj

kR

D

R

R

D

Rm

ww

ww

=

=

&

&1lnexp

*

2

*

1

Hscp khi1/kF



ijF

hydP

D

dmPe

=

&

Phn cc nngpha dung dchu vo ca mt skiu mun mng

Phn cc nngpha dch vo trong cc loi mun mng khc nhau

Chun sPecle

=

=

Sh

Pe

dk

PeD

ww

ww

hydF

ij

jj

jjexpexp

*

2

*

1


5/13

Vn chuyn vt cht trn bmt mngTrlc cp khi trong lp phtr

Tng quan gia cc dng dc theo chiu di mun z

di tngi

Dch vo

Dng nc lccc b

Dch nc lcchung

(1) Phn cc nng


Trlc cp khi trong lp phtr

Phn bnngtrong lpkhi dng mng bti xng

Lp

-


6/13

Vn chuyn vt cht trn bmt mngTrlc cp khi trong lp phtr

Phn cc nngtrong lptrong cc qu trnh khc nhau

Nc trong

p sut pha nc trong

Khi lng ring nc trong

Hskhuych tn

rng lp

Bdy lp

Phn cc nng


(2) Tn tht p sutTrlc cp khi trong lp phtr

Tn tht p sut trong lp

p sut trong thit bngng t

p

sutsaulphotng

Dng lc

Isopropanol- nc


7/13

Vn chuyn vt cht trn bmt mngDng pha trn hng trc /axial back mixing

Dng pha trn hng trc

c hiu l tt cc cc dngvn chuyn khng ngoi dngi lu

Phn bcc xung chuynng

Thiim pht sinh xung Thiimo

Xung chun khit=0

Xung bi suy gim do cc dng pha trn hng trc:phn bvn tc, dng xoy, khuych tn phn t,

Phn b i xng ti mithiim


Cc loi trlc v hiung thyng lc tcng ti qu trnh tiu ha cc mun mng

- Cn bng vt cht trong khng gian trc mng v sau mng

- Tn tht p sut trong khng gian sau mng

- Phn cc nngphia dch vo

- c tnh ca mng

- c tnh dng nc trong cc b


8/13

Vn chuyn vt cht trn bmt mngPhng php tnh ton cng sut lc cc bca mng

Hphng trnh tnh ton cng sut lc ca mng (trng hp tun theo m

hnh Ha tan Khuch tn)Phn cc nngpha dch vo

Trlc ca mng

Thm thu ngc(RO)

Thm bc (PV)

Trlc ca lp

Phn cc nngpha nc trong


Phng php tnh ton cng sut cc bca mng

Thm thu ngc: Hphng trnh tnh ton c kdn phn cc nngpha dchvo v trlc ca mng

Sh= f( Re, Sh, kch thc hnh hc)


9/13

Vn chuyn vt cht trn bmt mngPhng php tnh ton cng sut cc bca mng

Phn cc nngtrong qu trnh thm thu ngc


Phng php tnh ton cng sut cc bca mng

nh hng ca phn cc nngpha dchc ti dng qua mng trong cc trnghp khc nhau

Qu trnh mng

Hcht

Mng

Mun Loi ti Loi bn Loing


10/13

Vn chuyn vt cht trn bmt mngnh hng ca vtr lp hotng ca mng

Dung dch vo Nc trong

Phn cc nngpha dungdch vo

Lp

rng

Phn ccnngphanc trong

Lp hot

ng


nh hng ca vtr lp hotng ca mng

Hphng trnh tnh ton cng sut lc ca mng khi lp dtip xc vi dch votrong qu trnh RO


11/13

Vn chuyn vt cht trn bmt mngnh hng ca vtr lp hotng ca mng

Hphng trnh tnh ton cng sut lc ca mng khi lp dtip xc vi dch vo

trong qu trnh PV


nh hng ca vtr lp hotng ca mngHphng trnh tnh cthcho qu trnh RO v GP


12/13


Cc phng php tng cng qu trnh cp khi trnmng

- To ra dng nhiu pha

- Thm cc ccu to xoy trong khng gian dch vo: Feed-Spacer

- To mng rung khi lm vic

- a dchc vo mun di dng xung


Cc phng php tng cng qu trnh cp khi trnmng

S nguyn l pp to dnga pha


13/13


Dng Feed Spacer

S nguyn l pp dng Feed Spacer

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