A. Karimi_Kinetic Studies and Reactor Modelingpdf

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Title: Kinetic Studies and Reactor Modeling of Single StepH2S Removal Using Chelated Iron Solution

Authors: A. Karimi, A. Tavassoli, B. Nasernezhad

PII: S0263-8762(09)00307-4

DOI: doi:10.1016/j.cherd.2009.11.014

Reference: CHERD 415

To appear in:

Received date: 20-5-2009Revised date: 7-11-2009

Accepted date: 21-11-2009

Please cite this article as: Karimi, A., Tavassoli, A., Nasernezhad, B., Kinetic Studies

and Reactor Modeling of Single Step H2S Removal Using Chelated Iron Solution,

Chemical Engineering Research and Design (2008), doi:10.1016/j.cherd.2009.11.014

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Kinetic Studies and Reactor Modeling of Single Step H2S

Removal Using Chelated Iron Solution

A. Karimi

1

, A. Tavassoli

1

, B. Nasernezhad

2

1Gas Research Division, Research Institute of petroleum industry (RIPI)

[email protected] Engineering Department, Amir Kabir University

Abstract

Airlift reactor concept was used for hydrogen sulfide removal from acid gases using

chelated iron solution. Rate equations for absorption and regeneration reactions

were determined and finally, an Autosweet program was developed for design and

simulation of the reactor. Variations of the concentration profiles of the reactants

and products with time, the required time to achieve steady state conditions,

concentration profiles of two phases at steady state and volume of the reactor in

absorption and regeneration sections can be calculated based on implemented model

in this study. Comparison of theoretical and experimental results shows a good

agreement and justifies the model. Based on the model as a second stage of project,

a 1 m3 prototype reactor was designed and constructed at NIOC research institute.

Keywords: kinetics, modeling, airlift, chelated iron, hydrogen sulfide

Introduction

Liquid phase oxidation process using iron chelate catalytic solution (LOCAT) has

been employed for treatment of acid gas streams. However, the process was

identified economical for up to 850-1050 kg/hr of sulfur production, although much

larger systems have been installed [1]. Advantages of these systems include the

ability to treat both aerobic and non-aerobic gas streams, high H2S removal

anuscript
mailto:[email protected]:[email protected]:[email protected]


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efficiencies, great flexibility; essentially 100% turndown on H2S concentration in

feedstock, and quality and the production of innocuous products and byproducts.

The two most common processing schemes encountered in these systems are named

"Conventional" and "Autocirculation". The first one is employed for processing gas

streams, which are either combustible or cannot be contaminated with air. Here,

absorption and regeneration reactions occur in separate vessels. The second one is

used for processing acid gas streams (CO2 and H2S) or noncombustible streams in

which both absorption and regeneration reactions are carried out in a single vessel

according to the following equations respectively:

H2SFe2Fe2SH 232 (1)

OH2Fe2O2

1Fe2OH 32

2

2 (2)

The overall reaction is the reaction given in equation (3):

SOHO2

1

SH 222 (3)

The autocircualtion scheme of the reactor is illustrated in Fig. 1. The reactor

consists of three main zones; riser, downcomer and gas-liquid separator. In riser

both absorption and regeneration reactions take place. In the initial section of the

riser, in which the reaction of equation (1) occurs, acid gas is sparged and absorbed

into a catalytic solution. Then, the solution flows in regeneration section in which

air is sparged where the reaction of equation (2) occurs. The solution circulates due

to density difference created between riser and downcomer zones. As seen in Fig.

1, the two spargers for acid gas and air are placed in an appropriate flexible distance

to each other. The regenerated catalytic solution re-enters to the riser absorption

zone due to the presence of the natural circulation.


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In comparison with the conventional scheme, the unique feature of the

autocirculation reactor is that no pumps are required to circulate solution between

absorber and oxidizer. Therefore, these are generally less expensive units with few

operational problems related to sulfur plugging than usually reported for the other

scheme. However, due to presence of oxygen and sulfide ions, these units may

produce more byproducts.

Hydrodynamic parameters of this scheme such as gas hold up, liquid velocity,

pressure distribution and bubble diameter were determined in another work [2]. The

main objective of this paper is to determine reaction kinetic parameters for both

absorption and regeneration reactions and then presenting a model to simulate the

reactor behavior using airlift reactor concept which is commonly used for

fermentation or bio-reactions.

In fact, a little information concerning kinetic data has been revealed in the

literature. The absorption reaction between H2S and catalytic solution is fast and as

soon as H2S reaches to interface plane, the absorption reaction takes place between

two phases [3]. The method of how to measure the kinetics parameters and how to

imply an appropriate model interpreting the experimental data is very important for

determination of rate constant and the other required parameters. In addition the

literature shows a great controversy regarding kinetics parameters. The

investigations commonly confirm that the regeneration reaction can be considered

first order with respect to the oxygen concentration, [4, 5, 6] but there are different

information can be found regarding the order of reaction with respect to the chelated

iron II concentration. For example, Sada et al. reported this order equal to 0.536

[4], however, the other investigators reported it to be mostly equal one andtwo [5].


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Reviewing some papers shows that the order varies between one and two when pH

and concentration of chelated iron solution change.

Here, an experimental investigation is performed to determine rate equations for

RIPI20*, iron chelate catalytic solution (i.e. Fe-EDTA complex), and a model is

developed to predict variations of the concentration of the reactants and products

with time. The Autosweet program is also developed to estimate the time needed

to steady state conditions, concentration profile of two phases at steady state and

volume of the reactor needed to take place the absorption and regeneration reactions

within the safe zone operation and for a given condition. Experimental data obtained

from a bench scale reactor are in a good agreement with simulated reactor using the

program.

Experimental Setup

Kinetic experiments were carried out in a glass reactor illustrated in Fig. 2. The

reactor has 10 cm diameter and 20 cm height in which gas and liquid can be

contacted. Both phases are well mixed via two impellers located at two positions in

the bulk of gas and liquid on the agitator shaft. The agitator speed in all

experiments is constant and equal to 300 rpm. Six baffles, 1 cm in width, are placed

symmetrically to avoid the formation of vortex inside the reactor and make agitation

to take place completely.

Variations of iron concentration and dissolved oxygen in liquid phase are measured

and saved using an oxidation-reduction probe (ORP) and a DO electrode. Depending

Variations of iron concentration and dissolved oxygen in liquid phase are measured

and saved using an oxidation-reduction probe (ORP) and a DO electrode. Depending

on the purpose of experiment the electrodes are connected to a PentiumII personal

*RIPI20 is formulated by RIPI


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computer for data acquisition. Containers, V2, V3 and V4, are dry nitrogen,

hydrogen sulfide and air cylinders, respectively. A vacuum pump is used for

evacuation of the reactor and charging the catalytic solution from container V 6. Off

gases from the reactor can be gathered in vessel V5.

Absorption reaction kinetics

The reaction mechanism is as follows:

)L(2)aq(2)L(2)g(2 OHSHOHSH (4)

HSHSH )aq(2 (5)

HFe2SFe2HS 23 (6)

Equations (4) and (5) represent the absorption of H2S into the aqueous chelated iron

solution and its subsequent ionization, while equation (6) represents the oxidation of

the sulfide ions to elemental sulfur and the accompanying reduction of the ferric

iron to the ferrous state. The overall absorption reaction follows equation (1).

Writing the intrinsic rate equation in the power form yields:

1

3

1

2

2

2

m

Fe

n

SH1

SH

SH C.CKdt

dCr

(7)The aim here is to determine values of n1, m1 and K1. According to the following

equation, absorption rate of H2S in liquid phase is related to the gas phase

pressure[4]:

)dt

dP.(

T.R

VV.a.J

SHGLSH

2

2 (8)

The rate of absorption of H2S per unit of gas-liquid interface, SH 2J , is given as[7]:

)CC.(E.KJ SHi,SHSHLSH 2222 (9)


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Where LK the liquid-side mass-transfer cofficient, i,SH 2C the liquidside interfacial

H2S concentration and SH 2C the concentration of H2S in the liquid bulk (i.e., x

with x the distance from the gas-liquid interfac) and for fast reaction 0C SH2 . Also

the enhancement factor SH2E is the result of chemical reaction[7]. In chemically

enhanced reaction regim SH2E can be defined as [5]:

2

L

m

Fe1

SHK

C.K.DHaE

1

3

2 (10)

Since the solubility of H2S in the catalytic solution is relatively high, so it is

assumed that concentration ofH2S at interface is equal to its solubility:

He

PCC

SH*

SHi,SH

2

22(11)

C*H2S is equilibrium concentration of H2S in solution and He is Henrys law

constant. Combination of above equation results:

SHSHL

G

LSH

22

2 P.E.a.K.He.V

T.R.V

dt

dP (12)

t.E.a.K.He.V

T.R.V

P

Pln SHL

G

L

SH

0

SH

2

2

2 (13)

Substitution of equation (10) in equation (12) gives:

dt.C.K.D.a.He.VT.R.V

PdP 13

2

2 m

Fe1

G

L

SH

SH (14)

Determination ofn1: In this experiment a high concentration of chelated iron solution

about 10000 ppm is prepared. Thus, variations of the iron concentration can be

neglected. First of all, the glass reactor is evacuated and 700 cm3 of the 10000 ppm

of RIPI20 catalytic solution is charged inside the reactor. A little dry sulfur is added

on the liquid surface to avoid further contacts between gas and liquid before starting


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the experiment and data recording. Then, H2S is fed into the reactor and variations

of the gas pressure inside the reactor is recorded with time for a given condition.

Linear trend of the data in Fig. 3 indicates that the absorption reaction is first order

with respect to the hydrogen sulfide concentration.

Also plot ofSH

0

SH

2

2

P

Pln vs. time as shown in Fig. 3 turns out to be linear and its

intercept from the y-axis is zero, then according to equation (13), SH2E is

independent of SH 2P and the reaction is first order in H2S[8].

Determination of m1: During the experimental tests the pressure of the gas phase is

kept constant and high value via continuous injection of H2S in order to maintain its

concentration in excess. 700 cm3 of 2000 ppm of RIPI20 catalytic solution is

charged into the reactor and dry sulfur powder is added to the contact area inside the

reactor. Then agitator is turned on and data recording is started. Fig. 4 shows the

results of the experiment.Linear trend of the data indicates that absorption reaction

is first order as a function of the chelated iron III concentration[9].

According to equation (10), the enhancement factor for H2S is plotted respect to

concentration of chelated iron III solution in Fig. 5. The slope of the line is equal

to2

m1 [8]. This quantity is equal 0.53, which confirms that the reaction is first order

with respect to the chelated iron III concentration.

Determination of K1: In this step, variations of both reactants are measured with time

and none of them is excess. The reaction is started with a 2000 ppm of RIPI20

catalytic solution with H2S initial pressure equals to 46.7 millibar. Using equation

(14), the data are analyzed to determine rate constant and finally the rate equation

for absorption ofH2S in chelated iron solution at pH=8-10 and for T=22oC can be

derived as follows:


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)ionconcentrattime(815.16k,C.C.kdt

dCr 11abFeSHab

SH

SH 32

2

2(15)

Regeneration reaction kinetics:

Reaction mechanism is considered as follows:

)L(2)aq(2)L(2)g(2OHO

2

1OHO

2

1(16)

OH2Fe2OHFe2O2

1 32

2

)aq(2(17)

Considering power form for the intrinsic rate equation yields:

22

2

2

2

2

m

Fe

n

O2

Fe

FeC.C.K

dt

dCr (18)

Using isolation method, in each step concentration of one of the reactants is

considered to be high and variations of concentration of the other one is

investigated.

Determination of n2: The reactor is evacuated and 700ml of chelated iron II is fed

into it. Then, pure oxygen is injected to the system up to a known pressure and

variations of oxygen pressure with time is recorded. In Fig.6 variations of

2

2

O

0

O

P

PLn is plotted versus time. The straight line with correlation factor of 0.992

and slope of 0.0025 indicates that regeneration reaction is first order with respect to

the dissolved oxygen concentration[10].

Determination of m2: In this experiment, concentration of dissolved oxygen is excess

and variations of concentration of iron II with time is recorded. The gas phase with

a high flow rate is charged into the reactor through a gas sparger. Fig. 7 shows a


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linear trend for variations of2Fe

C

1, which indicates that the reaction is second order

with respect to the chelated iron II concentration[9].

According to the Fig. 8, slope of the curve

2O

2

Fe

C

Clog versus

2

2

O

Fe

C

rlog (i.e. 1.9933)

shows the order of the reaction with respect to the chelated iron II concentration.

This expresses that order of 2 is correct again[9].

Determination of K2: In this step, variations of both reactants are measured with time

and none of them is excess. Fig. 9 shows that the slope of the resultant line is

0.0185. Using this slope the rate constant can be calculated. The experiment is

repeated for different temperatures and the results are plotted in Fig. 10. Activation

energy, Arrhenius constant and rate constant for regeneration reaction can be

estimated as follow:

RT

E

o2

a

eKK (19)

s.mol/m7.381K 26o and mol/kJ159.25E a

Kinetic model

By applying mass balance equations for two elements in absorption and

regeneration sections respectively and combination of resulted intrinsic rate

equations with them, concentration profiles of the H2S and iron II are determined.

For this purpose, it is necessary that mentioned equations are coupled with

hydrodynamic model results determined in previous work. In this way, required

height for complete absorption of H2S and regeneration of reacted iron II will be

determined. Following assumptions are considered in regeneration section:


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1) Negligible changes in gas phase composition due to high flow rate of

the air injected.

2) The mass transfer of oxygen from gas to liquid phase as a rate-

limiting step.

3) Negligible axial dispersion.

Several experiments were carried out to correlate variations of volumetric mass

transfer coefficient with gas flow rate in the reactor[2,6]

Absorp t ion sect ion: An element of the absorption section is illustrated in Fig. 11.

Consideration of mass balance for gas and liquid phases around the element yields

following equations respectively [11]:

0dx.A).YY(P.a.KdYRT

PQ * SHSHgSHg 222 (20)

0dx.A).CC(a.K.EdYRT

PQ SH

*

SHLSHg 222(21)

0dx.A.r.b).1(dCQ SH1SHL 22 (22)

In which, rH2S is intrinsic rate equation of absorption reaction. In equation (21), E is

enhancement factor and in the industrial process, theoretically the relation of E

and 3FeC depends on the regime of mass transfer with reaction that occurs and

diffusion of the reactive components. E relates proportionally to 3FeC and an

istaneous reaction may well explain the results observed and can be calculated from

the following relation [5,10]:

*

SHL,SH1

FeL,Fe

22

33

C.D.b

C.D1E (23)

Here, b1 is the stochiometric coefficient of the absorption reaction.

Regeneration section: Mass balance for liquid phase around the element in

regeneration section results the following equation:


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0dx.A.r.b).1(dCQdx.A).1(dx

dCD 22

2

2 Fe2FeL2

Fe

L,Fe (24)

Assuming negligible axial dispersion, the first term will be omitted. Here, rFe2+ is

intrinsic rate equation for regeneration reaction.

2

FeO2

Fe

Fe2

2

2

2 CC.Kdt

dCr (25)

)RT

)mol

kJ(159.25

exp().smol

m(7.381K

2

6

2 (26)

Regeneration reaction is limited to the rate of mass transfer of the oxygen from gas

to liquid phase; therefore the rate of oxygen transfer per unit volume of the

dispersed phase is as below:

2

FeO2oOiOLFe 22222 CC.K])C()C[(.a.Kr (27)

In which is the effectiveness factor. The final rate equation for regeneration

reaction is:

a.K

1

C.K

1)C.(K*4

dt

dCr

L

2

Fe2

iOregFe

Fe2

2

2

2 (28)

Autosweet Program

Using determined rate equations for absorption and regeneration sections,

Autosweet program was prepared to predict overall performance of the reactor

and safe operating zone in both sections for a given condition. To solve above

equations, some hydrodynamic parameters such as gas holdup, liquid velocity,

pressure distribution, bubble diameter are required. These parameters were

investigated in simultaneous work of the author [2].


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In absorption section, the required height for complete absorption of H2S (safe

operating zone) and concentration profile of two phases at steady and unsteady state

are determined through simultaneous solution of equations (20) and (22). In

regeneration section, equations (24) and (27) are solved simultaneously to

determine concentration profile and percentage of conversion at both steady and

unsteady sates.

Simulation of reactor and comparison of results: The experimental reactor is made

from glass with dimensions given in Table 1. Table 2 shows the properties of the

catalytic solution, RIPI20, and acid gas used as feedstock. Results of the simulation

of the reactor such as concentration profile at steady state, variation of concentration

with time, variation of equilibrium concentration with air/H2S ratio and comparison

of the theoretical and experimental results are shown in Fig. 12, Figs. (13-1,13-2),

Figs. (14-1,14-2) respectively. Table 3 shows overall results of simulations and

resulting experiments.

Conclusion

1- The absorption reaction of hydrogen sulfide by chelated iron III is first order

with respect to the both reactants.

2- Regeneration reaction is first order with respect to the dissolved oxygen

concentration and is second order with respect to the Chelated iron II

concentration, when the concentration of catalytic solution varies between

1000-4000 ppm.

3- Comparison of the theoretical and experimental results shows a good

agreement and confirms the capability of the model implemented and the

Autosweet program.


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4- The results of this study were used to design a new reactor for H2S removal

at RIPI with about 1 m3 capacity and also for optimization of similar

reactors in operating units.

5- Application of such reactors forH2S removal is genuine and development of

the model is necessary for simulation of larger scale units.

Nomenclatures:

A Cross sectional area m2

a Interfacial area per unit volume of gas and liquid m2/m

3

b Stochiometric coefficient -

SH2C Concentration of hydrogen sulfide at gas bulk mol/m3

*

SH2C Concentration of hydrogen sulfide at interface mol/m3

FeC Concentration of iron in catalytic solution mol/m3

Ceq,Fe Concentration of ironat equilibrium mol/ m3

iO )C( 2 Concentration of oxygen at interface mol/m3

oO )C( 2 Initial concentration of oxygen mol/ m3

D Dispersion coefficient m2/s

E Enhancement factor -

Ea Activation energy kJ/mol

He Henrys law constant Pa.m

3

/mol

Ha Hatta number -

J Absorption rate mol/s

K Pre-exponential reaction rate constant m6/mol

2.s

K1 Absorption rate constant m3/mol.s

K2 Regeneration rate constan t m6/mol

2.s

Kg Gas phase mass transfer coefficient m/s

KL Liquid phase mass transfer coefficient m/s


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m , n Order of a reactant in reaction mol/m2.s

P Pressure Pa

Po

initial value of Pressure for any species Pa

Qg Volumetric gas flow rate m3

/s

R Gas constant 8.314 J/ mol.k

r Reaction rate mol/s

T Time s

VL Volume of liquid phase m3

VG Volume of gas phase m3

Z Distance from gas sparger m

Effectiveness factor -

Average gas holdup at cross section -

References

[1] G. Nagl, Removing hydrogen sulfide, Hydrocarbon engineering, 6 (2001) 35-38

[2] M.A. Jafari nasr, H. Bakhtiyari, A. Karimi, A. Tavasoli, Single Step H2S

Removal Using Chelated Iron Solution: Investigation of hydrodynamic parameters

in an internal loop air lift reactor, I. J. of Sci. & Tech., Trans. B, 28(B6) (2004) 643-

651.

[3] M. Abedinzadegan, M.R. Jafari Nasr, A mathematical model describing the ARI

Autocirculation reactor for low temperature conversion of H2S into sulfur,

Chem.Eng.& Technol., 17 (1994) 141-143.

[4] E. Sada, H. Kumazawa, H. Machida, Oxidation Kinetics of FeIIEDTA and FeII

NTA Chelates by Dissolved Oxygen, Ind. Eng. Res., 26 (1987) 1468-1472.

[5] H. J. Wubs, A. A. C. M. Beenackers, Kinetics of the Oxidation of Ferrous

Chelates of EDTA and HEDTA in Aqueous Solution, Ind. Eng. Chem. Res., 32

(1993) 2580-2594.


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[6] A. Karimi, A. Jebreili Jolodar, A. A. RajabPour, H. R. Bakhtiary, Mass transfer

study in AUTOCIRCULATION reactor for H2S removal from acid gas streams",

Petroleum & Coal, 49 (1) (2007) 27-33.

[7] J.F. Demmink, A. A. C. M. Beenackers, Gas desulfurization with ferric chelates

EDTA and HEDTA, new model for the oxidative absorption of hydrogen sulfide,

Ind. Eng. Chem. Res., 37 (1998) 1444-1453.

[8] H. J. Wubs, A. A. C. M. Beenackers, Kinetics of H2S Absorption into Aqueous

Ferric Solutions of EDTA and HEDTA, AIChE Journal, 40(3) (1994) 433-443.

[9] O. Levenspiel, Chemical Reaction Engineering, 2nd Edition, Wiley Eastern

University, New York, 1989.

[10] J.F. Demmink, A. A. C. M. Beenackers, Oxidation of Ferrous Nitrilotriacetic

Acid with Oxygen: A Model For Oxygen Mass Transfer Parallel to Reaction

Kinetics, Ind. Eng. Chem. Res., 36 (1997) 1989-2005.

[11] A. Gianetto, P.L. Silveston, Multiphase Chemical Reactors, Hemisphere

Publishing Corporation, 1995.

Acknowledgment

The author wish to express his appreciation to RIPI of National Iranian Oil

Company (NIOC) for the financial support of this research, project Nos:

71010109,71010112.

Address

Correspondence concerning this paper should be addressed to A. Karimi, Gas

research division, Research Institute of Petroleum Industry (RIPI), National Iranian

Oil Company (NIOC), West Blvd. Azadi Sport Complex, P. O. Box: 14665-1998,

Tehran, Iran


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Tabels and Figures:Table 1 - Experimental glass reactor dimensions

Length (m) Diameter

(m)

Riser 1.9 0.145

Downcomer 1.8 0.174

Gas-liquid separator 0.62 0.25

Table 2 - Properties of the catalytic solution, RIPI20

and acid gas used as feedstock

Property Viscosity

(Pa.s)

Density

(kg/m3)

Concentration

Liquid 1.005*10-3

1000 2000 ppm ironchelate

Gas 1.65*10-5

1.3 2 vol.% of H2S in acid gas

Table 3 - Overall simulation resultsLiquid

residencetime / s

Liquid

downcomervelocity /(m/s)

Liquid

massvelocity

/ (kg/s)

Average

gas holdup

Steady state

oxidationreduction

potential /

mV

H2S

absorptionlength / m

CFe+2 at the

end ofabsorption

zone / ppm

CFe+2 at the

end ofregeneration

zone / ppm

33.6 0.175 0.89 0.012% -101 0.03 266 69

LIQUID

STORAGE

TANK

V5

V6V1

D.O .Meter

orORP

COMPUTER

BYPASS

IBM PS / 2

Agitator

pH

electdrode

Vacuum

pump

U-tube

manometer

V4

Air

V3

H2SN2

V2

Fig.1 - Autocirculation scheme of the reactor. Fig.2 - Glass reactor for kinetic experiments.

AA

A A


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Fig.3Determination of n1

Fig.4Determination of m1

SH

SHo

2

2

P

Pln

3

30

Fe

Fe

C

Cnl


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Fig.5 - Determination of m1using eq.(10),Slopeof the line is equal to m1/2=0.5.

Fig.6-Determination of n2.

EH2S

2

2

O

o

O

P

Pnl


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Fig.7-Determination of m2 using the methodpresented by Levenspiel [9].

Fig.8-Determination of m2,Slope of thecurve is equal to reaction order [9].

2

2

O

Fe

CClog

2

2

O

Fe

C

r

log

1

3)

/

/(

1

2

m

mol

CFe


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Fig.9 - Rate constant for regenerationreaction at 25oC

Fig.10-Variation of regeneration reaction

rate constant with temperature.

2

2

O

Fe

C

Cln

ln

K


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CA

YA

x + dxx

dxdx

dYY AA

dxdx

dCC AA

dxdx

dT+TT

)gas(AeA

Y

eAC

eBC

Liquid

zB+A P2k

fAC

fBC

fAY

gQ

lQdx

dx

dCC BB

Fig.11-An element of absorption section.

Fig.12- Concentration profile along riser at steady state

Fe+

Fe3+

CFe

3+/

m

CFe

2+/

m


23/24

Page 22 of 23

Accepted

Manus

cript

22

Fig.13-1-Variations of CFe2+

with time at

the end of regeneration section.

Fig.13-2-Variations of CFe3+

with time at

the end of regeneration section

H2S =0.95 (cm3 / s)

AIR=66.21 (cm3 / s)

N2=46.35 (cm3 / s)

H2S =0.95 (cm3 / s)

AIR=66.21 (cm3 / s)N2=46.35 (cm

3 / s)CFe

3+/

m

CFe

2+/

m


24/24

Accepted

Manus

cript

Fig.14-1-Variations of equilibrium

concentration of Fe2+ vs. Air/H2Svolume ratio at feedstock.

Fig.14-2-Variations of equilibrium

concentration of Fe3+vs. Air/H2S

volume ratio at feedstock.

N2=46.35 (cm3 / s)

H2S = 0.95 (cm3 / s)

N2=46.35 (cm / s)H2S = 0.95 (cm

3 / s)

AIR / H2S Vol. Ratio

AIR / H2S Vol. Ratio

Ceq,Fe

2+

/ppm

Ceq,Fe

3+

/ppm

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A. Karimi_Kinetic Studies and Reactor Modelingpdf

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