MODELING & SIMULATION OF DIRECT CONTACT MEMBRANE

DISTILLATION(DCMD)

DATE: 11TH MAY 2011

CONTENTS

1. Introduction

2. Literature survey

3. Modeling

4. Results and Discussion

5. Conclusion

6. Sample simulation

References

1. INTRODUCTION

1. Membrane Distillation○ Classification of Membrane Distillation

2. Direct Contact Membrane Distillation(DCMD)

• Advantages of DCMD• Application of DCMD

MEMBRANE DISTILLATION(MD)

Membrane distillation (MD) is a mass transport process of volatile components that takes place across the pores of non-wetted membranes.

In this process, a hydrophobic porous membrane is used, which is in direct contact with a hot feed.

CLASSIFICATION OF MD

Direct contact Membrane Distillation(DCMD)

Air gap membrane distillation(AGMD)

Sweep gas membrane distillation(SGMD)

Vacuum membrane distillation(VMD)

DCMD DCMD is thermally driven process. In DCMD the permeate side is in direct contact with cold

aqueous solution. Trans-membrane temperature difference induces a

vapour pressure difference causing vapour to pass through membrane pores.

Evaporation of volatile component of a feed at warm feed membrane interface.

Transfer of vapour. Condensation of permeate at the other end (distillate

end). Almost negligible pressure difference across the

membrane.

CONFIGURATION OF DCMD

ADVANTAGES OF DCMD Practically complete (100%) rejection of

dissolved non-volatile species. Lower operating pressure than pressure driven

membrane. Reduced vapour space compared to

conventional distillation. Lower operating temperature of feed enables

the utilization of waste heat as a preferable energy resources.

Theoretically almost 100 % of purity is possible.

APPLICATION OF DCMD

Vapor permeation Water purification Fruit juice concentration Concentration of acid solution Waste water treatment

2. LITERATURE SURVEY

Recent studies in DCMD Operating variables affecting DCMD

process Mechanism: Desalination using DCMD Model review from literature Data Collected

RECENT STUDIES IN DCMDYear Topic Researchers

2010 Modeling of Direct Contact Membrane Distillation for Desalination.

Edward Close, Eva Sørensen,Department of Chemical Engineering, University College London (UCL), Torrington

Composite Membranes for Membrane Distillation Desalination Process.

Sai R. Pinappu,Chemical Engineering Department, New Mexico State University

A theoretical study of a direct contact membrane distillation system coupled to a salt-gradient solar pond for terminal takes reclamation.

Francisco Suarez, Scott W. Tyler, Amy E. Childress,University of Nevada, Reno, USA

2009 Surface modification of nanostructured ceramic membranes for direct contact membrane distillation.

Z.D. Hendren, J. Brant, M.R. Wiesner ,Department of Civil and Environmental Engineering, Duke University, Durham, USA

Year Topic Researchers

2008 Solar desalination of brackish water using membrane distillation process.

Shuguang Deng ,New Mexico Water Resources Research Institute, New Mexico State University

2007 The potential of membrane distillation as a stand-alone desalination process.

A.M. Alklaibi Jeddah College of Technology, KSA

2006 A framework for better understanding membrane distillation separation process.

(i) M.S. El-Bourawi , (i)Z. Ding , R. Maa, (ii)M. Khayet (i)State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing ,China (ii)Department of Applied Physics, University Complutense of Madrid, Spain

Year Topic Reseacher

2005 Mass transfer mechanisms and transport resistances in direct contact membrane distillation process

Surapit Srisurichana, Ratana Jiraratananona , A.G. Faneb, King Mongkut’s University of Technology Bangkok, Thailand

2004 Desalination by membrane distillation adopting a hydrophilic membrane

Ping Peng, A.G. Fane, Xiaodong Li UNESCO Centre for Membrane Science and Technology, University of New South Wales, Australia .

2003 Experimental study of desalination using direct contact membrane distillation: a new approach to flux

Tzahi Y. Cath, V. Dean Adams, Amy E. Childress University of Nevada, Reno, NV, USA

2002 Mathematical modeling of influence of porous structure a membrane on its vapor-conductivity in the process of membrane distillation

(i)Valery V. Ugrozova, (ii) Inga B. Elkinab (i)Moscow State University of Food Industry, Moscow, Russia (ii)Tufts University, Medford, MA 02155, USA

Year Topic Researchers

2001 DCMD with Crystallization Applied to NaCl Solution.

M. GRYTA, Institute of Chemical Technology and Environmental Engineering, Technical University of Szczecin, Poland

2000 Membrane Distillation: Applications in Technology and Environmental Protection.

M. Tomaszewska Institute of Inorganic Chemical Technology, Technical University of Szczecin, Poland

OPERATING VARIABLES AFFECTING DCMD PROCESS

Feed inlet concentration Feed temperature Cold liquid temperature Feed circulation velocity and stirring rate Permeate velocity Vapor pressure difference Membrane parameter

Pore sizePorosityThickness

MECHANISM: DESALINATION USING DCMD

MODEL REVIEW FROM LITERATURE

From: Edward Close and Eva Sorensen, Modelling of DCMD for Desalination, Department of Chemical Engineering, University College London, Torrington

Rm(t) : membrane resistanceRc(t): concentration polarization resistanceRf(t): membrane fouling resistanceYln: logarithm mean pressure of gas

From: Yanbin Yun, Runyu Ma, Wenzhen Zhang, A.G.Fane, Jiding Li, DCMD mechanism for high Concentration NaCl Solutions, Department of Chemical Engineering, Tsinghua University, Beijing, China

LIST OF DATA USED FROM LITERATURE

Porosity: ԑ = 0.6 Membrane thickness: δ = 100μm Nominal pore size: r= 0.3 μm Tortuosity: τ = 2 (ԑ/τ)δ = 3000 m-1 We are using standard form of

correlation for heat transfer:  Nu= 0.023 Re0.8 Pr 0.33

{Duittus-Boiler correlation}

 Nu= Nussel number Re= Reynolds number :

1035<Re<5125 Pr= Prendtle number : 2.7<Pr<3.9 For feed side:   Ref = 1300

Velocity: uf = 0.1 m/s μ=0.54cp Density of feed: ρ= 1034Kg/m3

Prandtle number: Pr = 3.1

Nu=12.16 Nu=hf.D/K 

From experiment we took, D=1.6cm Kwater= 0.58 W/m 

Thus, hf=760W/m2K 

hm= (ԑkg + (1-ԑ)km )/δ

kg= 0.016

km=0.05   hm=296 W/m2 K

For permeate side: Rep= 676

hp = 222 W/m2K 

∆Hv=2270 Joules/Kg

ADDITIONAL EQUATIONS USED

ρf= [(2160 xf+ (1-xf) ]

μcp= C1+ C2exp(x1T) +C3exp(x3m) +C4exp[x3(0.01T+m)] +C5exp[x4(0.01T-m)]

Cpf= (xfCpNaCl/MNaCl) + (1-xf)(a+bT+cT2+ dT3)MNaCl

m= molality of solution = 1000 Xf/58.5

FROM: aOzbek, H., Viscosity of aqueous sodium chloride solutions from 0 - 150oC, Lawrence Berkeley National Laboratory- 09-10-2010http://escholarship.org/uc/item/3jp6n2bfb http://en.wikipedia.org/wiki/Viscosityc Himmelblau David M., Basic principles and calculations in chemical engineering, Sixth Edit-ion, Pearson Education

3. MODELING

Assumptions used in mathematical modeling:

The contribution of Poiseuille flow to mass transfer is neglected.

Kinetic effect at the vapour liquid interface are neglected.

Membrane should not alter vapour liquid equilibrium of different components.

The permeation of vapour through the membrane is regulated by Knudsen-molecular diffusion mechanism.

Mass Transfer in DCMD:

Heat transfer in DCMD:

4. RESULTS AND DISCUSSTION

• Effect of feed flow rate on flux• Effect of salt concentration• Effect of feed temperature on permeate flux• Effect of permeate temperature on flux• Effect of membrane thickness on Flux• Effect of membrane porosity on Flux• Effect of membrane pore diameter on flux• Effect of Feed side Heat transfer coefficient

The computational simulation of each operating parameter v/s permeate flux have been carried out using MATLAB

The experimental data were collected from the following:

1. Stephanie Lacoursiere, Water purification by membrane distillation, McGill University, Montreal, Canada (2005)

2. Dr. Kamalesh K. Sirkar, Dr. Baoan Li, “Novel membrane and device for Direct contact membrane distillation-based desalination process: phase II ”, New Jersey Institute of Technology, Newark, New Jersey (July 2003)

EFFECT OF FEED FLOW RATE ON FLUX

Feed flow rate increases sharply at lower flow rate and reaches asymptotes at higher flow rates.

EFFECT OF SALT CONCENTRATION

Slight decreases in flux is observed with increase in feed concentration

EFFECT OF FEED TEMPERATURE ON PERMEATE FLUX

Flux increases exponentially with increase in feed temperature

EFFECT OF PERMEATE TEMPERATURE ON FLUX

Decrease in flux observed on increase in permeate temperture

EFFECT OF MEMBRANE THICKNESS ON FLUX

Flux decreases sharply with increase in membrane thickness

EFFECT OF POROSITY ON FLUX

A steep increase in flux is observed on increasing the porosity

EFFECT OF PORE DIAMETER ON FLUX

Flux increases almost linearly on increase in pore diameter

EFFECT OF FEED SIDE HEAT TRANSFER COEFFICIENT

Flux increases linearly with increase in feed side heat transfer coefficient

5. CONCLUSION

Close relation was found between the results given by the model and actual experiments presented in the literature.

Using this model, we can now determine the optimal operation and design of this unit.

Where there were conflicting results in the literature regarding the effect of the variables on the flux, the model was able to provide an explanation.

6. SAMPLE SIMULATION IN MATLAB

Thickness v/s Flux

 

d2=[.000025 .000045 .000056 .000098 .000150 .000250 .000350];

for i=1:7

Tf=323;

Tp=298;

E=0.6;

M=.018;

M1=.0585;

R=8.314;

d1=3.*10.^-7;%pore dia

D=.016;%dia of duct

Pt=(1.01).*(10.^5);

t=2;%totiosity

Ks=0.05;

Kg=0.0235;

Kf=.58;

Kp=.58;

Km=((E).*(Kg)+((1-E).*(Ks)));

Hm=((Km)./(d2(i)));

Xf=.03;

Xfm(1)=Xf;

m=(Xf.*1000)./(58.5);

Tfm(1)=Tf;

Tpm(1)=Tp;

%Reynolds Number Feed Side

df=(Xf.*((2.16).*(10.^3))+(1-Xf).*((999.8395)./(1+0.0002.*(Tf-273))));

Vf=.1;

A11=0.1256735+(1.265347).*exp((-0.04296718).*(Tf-273))-(1.105369).*exp((0.3710073).*m);

B11=(0.2044679).*exp(0.4230889.*((0.01).*(Tf-273)+m))+(1.308779).*exp((-0.3259828).*((0.01).*(Tf-273)-m));

Uf=(A11+B11).*(10.^-3);

Ref=(df.*Vf.*(D))./(Uf);

%Reynolds Number Permeate Side

Vp=.1;

dp=(999.8395)./(1+0.0002.*(Tp-273));

Up=((2.414).*(10.^-5).*10.^((247.8)./(Tp-140)));

Rep=(dp.*Vp.*(D))./(Up);

%Feed side Cpf

Aa=18.2964;

Bb=(47.212).*(10.^-2);

Cc=(-133.88).*(10.^-5);

Dd=(1314.2).*(10.^-9);

Cpf=(Xf.*50.*(M1.^-1)+(1-Xf).*(Aa+(Bb.*Tf)+(Cc.*(Tf.^2))+Dd.*(Tf.^3)).*(M.^-1));

% permeate side Cpp

Cpp=(Aa+(Bb.*Tp)+(Cc.*(Tp.^2))+Dd.*(Tp.^3)).*(M.^-1);

S=(2.303).*(8.3144);Ppm(1)=exp(23.238-(3841./(Tpm(1)-45)));Pofm(1)=exp(23.238-(3841./(Tfm(1)-45)));Pfm(1)=(1-Xfm(1)).*(1-0.5.*(Xfm(1))-10.*(Xfm(1).^2)).*(Pofm(1)); Tm(1)=((Tfm(1)+Tpm(1))./2); Dab(1)=(((1.895).*(10.^(-5))).*(Tm(1).^2.02))./(Pt); SS(1)=((1.895).*(10.^(-5))).*(Tm(1).^2.02); YY(1)=(Pt-Pfm(1));Y(1)=(YY(1))./(SS(1)); X(1)=(Pt-Ppm(1))./SS(1);C(1)=((.75)./d1).*((((6.28).*M)./(R.*Tm(1))).^(0.5));B(1)=(E./(t.*d2(i))).*(SS(1)./(R.*Tm(1))).*log((X(1)+C(1))./(Y(1)+C(1)));for j=1:10Z(j)=(Pfm(j)./Ppm(j));a(j)=(Tpm(j).^(-1));b(j)=Tfm(j).^(-1);TT(j)=((a(j))-(b(j))).^(-1);A(j)=(S).*(log10(Z(j))).*(TT(j)).*((.018).^-1)./(10.^3);%heat of vaporisation Dab(j)=(((1.895).*(10.^(-5))).*(Tm(j).^2.02))./(Pt); % Schmidt NumberScf(j)=(Uf)./((df).*(Dab(j))); %Pradetal Number of Feed SidePrf(j)=((Uf.*Cpf)./(Kf)); %Prandetal Number of permeate sidePrp(j)=((Up.*Cpp)./(Kp)); %Nusselt Number for feed sideNuf(j)=(0.023).*((Ref).^0.8).*((Prf(j)).^0.3); %Nusselt Number for Permeate sideNup(j)=(0.023).*((Rep).^0.8).*((Prp(j)).^0.3);% Feed side Heat transfer coefficientHf(j)=((Kf).*(Nuf(j)))./(D); Ks(j)=((0.023).*((Ref).^0.8).*((Scf(j)).^0.33).*(Dab(j)))./(D); %Permeate side Heat transfer coefficientHp(j)=((Kp).*(Nup(j)))./(D); Tfm(j+1)=(Hm.*(Tp+Tf.*(Hf(j)./Hp(j)))+Hf(j).*Tf-(B(j)).*(A(j)))./(Hm+Hf(j).*(1+Hm./Hp(j)));

pm(j+1)=(Hm.*(Tf+(Tp.*(Hp(j)./Hf(j))))+Hp(j).*Tp+(B(j)).*(A(j)))./(Hm+Hp(j).*(1+(Hm./Hf(j))));Xfm(j+1)=(Xf).*exp((B(j))./((Kf).*(df)));Ppm(j+1)=exp(23.238-(3841./(Tpm(j+1)-45)));Pofm(j+1)=exp(23.238-(3841./(Tfm(j+1)-45)));Pfm(j+1)=(1-Xfm(j+1)).*(1-0.5.*(Xfm(j+1))-10.*(Xfm(j+1).^2)).*(Pofm(j+1)); Tm(j+1)=((Tfm(j+1)+Tpm(j+1))./2);SS(j+1)=((1.895).*(10.^(-5))).*(Tm(j+1).^2.02);YY(j+1)=(Pt-Pfm(j+1));Y(j+1)=(YY(j))./(SS(j)); X(j+1)=(Pt-Ppm(j+1))./SS(j+1);C(j+1)=((.75)./d1).*((((6.28).*M)./(R.*Tm(j+1))).^(0.5));B(j+1)=(E./(t.*d2(i))).*(SS(j+1)./(R.*Tm(j+1))).*log((X(j+1)+C(j+1))./(Y(j+1)+C(j+1))); if B(j+1)<B(j) AA(j+1)=B(j+1); BB(j+1)=B(j); else AA(j+1)=B(j); BB(j+1)=B(j+1); end FF(j+1)=((.05).*(B(j+1))); if le((BB(j+1)-AA(j+1)),FF(j+1))==1 V(i)=B(j+1); break endendh1=plot(d2,V);set(h1,'marker','<','markerFacecolor','g','linewidth',2)title('Graph-Thickness v/s Flux','fontsize',20)xlabel('Thickness (micro meter)')ylabel('Flux(N) [Kg.m^-2.Sec^-1]') hold onV=[.0845 .0754 .0689 .0468 .0465 .0298 .0197];h2=plot(d2,V,'linestyle','none');set(h2,'marker','s','markerFacecolor','r') legend('Theoritical Data','experiment Data') hold off 

REFERENCES El-Bourawi, M. S., Ding, Z., Ma, R., and Khayet, M. (2006). "A framework for better understanding membrane

distillation separation process." Journal of Membrane Science, 285(1-2), 4-29 .

Toraj Mohammadi , Mohammad Ali Safavi,⁎ Application of Taguchi method in optimization of desalination by vacuum membrane distillation,222-252

Yanbin Yuna, Runyu Mab, Wenzhen Zhangc, A.G. Fanec, Jiding Lia, Direct contact membrane distillation mechanism for high concentration NaCl solu tion

M. GRYTA, Department of Water Technology and Environmental Engineering, Institute of Chemical Technology and Environmental Engineering, Technical University of Szczecin, Poland

Valery V. Ugrozova*, Inga B. Elkinaba,Moscow State University of Food Industry, 11 Volokolamskoe Rd., Moscow, 125080, Russia

Tufts University, Chemical and Biological Engineering Department, 4 Colby St., Medford, MA 02155, USA

Tzahi Y. Cath, V. Dean Adams, Amy E. Childress Department of Civil Engineering, University of Nevada, Reno, ∗NV 89557, USA

Ping Peng, A.G. Fane, Xiaodong Li ,UNESCO Centre for Membrane Science and Technology, University of New South Wales, Australia

Surapit Srisurichan a, Ratana Jiraratananon , A.G. Fane ,Department of chemical engineering, King Mongkuts �University of Technology Thonburi, 10140 Bangkok, Thailand

M.S. El-Bourawi a, Z. Ding a, R. Maa, M. Khayet, State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, PR China

Department of Applied Physics I, Faculty of Physics, University Complutense of Madrid, Avda. Complutense of Madrid s/n, 28040 Madrid, Spain

A.M. Alklaibi, Jeddah College of Technology, P.O. Box 46716, Jeddah 21542, KSA

Edward Close, Eva Sørensen,Department of Chemical Engineering, University College London (UCL), Torrington

Dr. Kamalesh K. Sirkar, Dr. Baoan Li ,Novel membrane and device for DCMD-based desalination process: phase-II ,New Jersey Institute of Technology, Newark, New Jersey

Stephanie Lacoursiere, Water purification by membrane distillation, McGill University, Montreal, Canada

M. Tomaszewska Institute of Inorganic Chemical Technology, Technical University of Szczecin,Poland

Bouguecha, S., Chouikh, R., and Dhahbi, M. (2003). "Numerical study of the coupled heat and mass transfer in membrane distillation* 1." Desalination, 152(1-3), 245-252.

Calabro, V., Jiao, B. L., and Drioli, E. (1994). "Theoretical and experimental study on membrane distillation in the concentration of orange juice." Industrial & Engineering Chemistry Research, 33(7), 1803-1808.

Cath, T. Y., Adams, V. D., and Childress, A. E. (2004). "Experimental study of desalination using direct contact membrane distillation: a new approach to flux enhancement." Journal of Membrane Science, 228(1), 5-16.

Chernyshov, M. N., Meindersma, G. W., and de Haan, A. B. (2003). "Modelling temperature and salt concentration distribution in membrane distillation feed channel**." Desalination, 157(1-3), 315-324.

Close, E., and Sørensen, E. (2010). "Modelling of Direct Contact Membrane Distillation for Desalination." Computer Aided Chemical Engineering, 28, 649-654.

Foster, P. J., Burgoyne, A., and Vahdati, M. M. (2001). "Improved process topology for membrane distillation." Separation and Purification Technology, 21(3), 205-217.

Gryta, M., and Tomaszewska, M. (1998). "Heat transport in the membrane distillation process." Journal of Membrane Science, 144(1-2), 211-222

Izquierdo-Gil, M. A., and Jonsson, G. (2003). "Factors affecting flux and ethanol separation performance in vacuum membrane distillation (VMD)." Journal of membrane science, 214(1), 113-130.

Kimura, S., and Nakao, S. I. (1987). "Transport phenomena in membrane distillation* 1." Journal of Membrane Science, 33(3), 285-298.

Lagan, F., Barbieri, G., and Drioli, E. (2000). "Direct contact membrane distillation: modelling and concentration experiments." Journal of Membrane Science, 166(1), 1-11.

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