the atomic energy organization of iran (aeoi) a-10!1!50-552728c

7/31/2019 The Atomic Energy Organization of Iran (AEOI) a-10!1!50-552728c

1/8

J. of Nuclear Sci. and Tech.

5350-431389No. 53, pp. 43-50, 2010

Sci. and Tech. note

HF

*12

2

1

-1 -11365-4563:

2- 11365-8486:

.:

.)(

HF.

.30.

.

.

9/125/160/34.

:

Equilibrium Curve Determination of HF Adsorption by Activated Carbon

H. Bahrami*1,2, S.J. Safdari2, S.M.A. Mousavian1

1- Department of Chemical Engineering, Faculty of Engineering, University of Tehran, P.O. Box: 11365-4563, Tehran-Iran

2- Nuclear Fuel Cycle Research School, Nuclear Science and Technology Research Institute, AEOI, P.O.Box: 11365-8486,Tehran Iran

Abstract:One of the byproducts of uranium enrichment industry is hydrogen fluoride gas. Due to thetoxicity and corrosivity of the molecule, it has adverse effects on the environment and the process.

Therefore, it must be removed by adsorption towers. The activated carbon is one of the proposed sorbentfor the adsorption. Hydrogen fluoride adsorption equilibrium curve gives important information for

designing the adsorption towers. In this article, the hydrogen fluoride adsorption and adsorption factors

were determined experimentally, and four different types of carbon have been used. The operating

pressure in all tests was less than 30 mbar. Comparison between the obtained experimental equilibrium

curves shows that the first, second and fourth types of activated carbon are suitable for the adsorption ofhydrogen fluoride. The experimental data were fitted using mathematical models of Longmuir,

Freundlich, Toth and Henry. The results show that Toth mathematical model is more suitable than other

models. Also, the absolute error were predicted by the model of Toth for the first, second and fourth

types of the activated carbon were 12.9, 16.5 and 34 percent, respectively.

Keywords: Hydrogen Fluoride, Adsorption, Activated Carbon, Equilibrium Curve, Isotherm,Uranium Enrichment

:[email protected]*email27/2/89:31/5/88:

43


2/8

HF

44

1-

.

.

UF)6(.

.]1[

.

.

.

.]2[

.

.

.

.

.)1(

.

.

.

.

.

.

.]34[

]5[)2(

]6[]7[

]89[.

]101112[.]10[

.

.]11[

.

.]12[

.

.]1314[

.

.

.

.


3/8

531389

45

.

.

. 30.

2-

2-1

1.

-

:

.- :

.- :

10001/010001/0

.

- :.

- :HF.

- :HF

.

-HF2N:HF98/9999/99.

.

- : .HF

369/0 245/5.

1.

1-.

1-

(mm)

)3(kg/m

)g/2(m

)

(

3530-48011001

4510-46011001

4560100012

5/242011001

2-2

HFHF .

..

..

)1(

2

112

V

VPP =

1P1V2P2V.

. )2(

]15[

PlPl

10mbar 1000mbar SV1

Reservoir Tank

Vacuum Pump

N.V.e N.V.Micro Valve

N2 HF

SV3

Adsorbent Vessel

Tl

SV2


4/8

HF

46

)2(TR

MVPm =

MV)(P)(

T)(R31/8((.)2(

.

.

.30

) (51020304060

.

. )1SV2SV3SV(1

02/0

. .)1SV(

.

0003/0

.)3SV(

51020304060.

)2SV()3SV(

. .

.

3-

.)245/25(

3025

.

]1617[.

)3(nkPq

1

=

q

PKn.

n=1.

)qP(

)4(q HP=

2-.

3-.

2 4 6 8 10 12 14 16 18 20 22

20

40

60

80

100

120

Experimental at 25.5 C

Toth

Second type of activated carbon

q(gradsorbate/kgactivatedcarbon)

P (mbar)

2 4 6 8 10 12 14 16 18 20 22

20

40

60

80

100

120

Experimental at 24 C

Toth

First type of activated carbon


P (mbar)


5/8

531389

47

4-.

.-5

.

.

.

.

. bqm

)5(

1

mq bP

q

bP

=

+

)6(

( ) tt t1

t

t

t

Pb

Pmq

+

=

2.

2-

T(oC)

bqm(gr HF/gr carbon)

r-squareerror

%knr-squareerror%

240658/0.2239/09973/04/5802183/0718/19965/05/38

5/2505775/02924/09943/09/5301955/0595/19976/00/30

5/255-

10259/34/3129054/05/194003713/06747/09588/08/225

2507385/02363/09894/00/3701875/0488/19892/05/61

T(oC)btmtttr-squareerror%Hr-squareerror%24976/29421/03529/09980/09/12008492/09613/07/181

5/25432/38814/03834/09969/05/16007092/09731/05/153

5/257492/04/11806989/06168/01/31301018/09696/05/194

2539/102647/08807/09869/00/34007766/09355/01/198

2 4 6 8 10 12 14 16 18 20

20

40

60

80

100

120

140

Experimental at 25.5 C

Toth

Forth type of activated carbon


P (mbar)

2 4 6 8 10 12

20

40

60

80

100

120

140

160

Experimental at 25 C

Henry

Third type of act ivated carbon

q(gradsorbate/k

gactivatedcarbon)

P (mbar)


6/8

HF

48

HF

3024

2.2

.

.

.

.2

HF30

.

2.

.

.

9/12HF

.

HF

305/25

3.

3HF

.HF

.2

HF30

.

HF5/16

30.

4HF

30

.

.HF

.

.

1

.

HFHF

. HF6UF

2F2UO.

.

.

2

.

HF5

30

.23

HF

.

.

.2

.

HF0/34

.30

.


7/8

531389

49

HF6

.

.HF

.

HF

99

19

19

.HF

2

.2

1315

1315

.

HF7

.HF

.7

.

6- .

-7 .

-4

-

HF.

-

HF

.

-

.

-

.

:

1- Cold Trap

2- NOX

0 50 100 1500

50

100

150

% Abs. Error of first Carbon=12.9

%Abs.Error of second Carbon=16.5

%Abs.Error of forth Carbon=34.0

q(Model)

q (Experiment)

2 4 6 8 10 12 14 16 18 20 22

20

40

60

80

100

120

140

160

First type at 24 C

Second type at 25.5 C

Third type at 25 C

Forth type at 25.5 C


P (mbar)

CC

CC


8/8

the atomic energy organization of iran (aeoi) a-10!1!50-552728c

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