HEAT AND MASS TRANSFER FOR PRODUCTION OF JAGGERY (GUR)
By
OM PRAKASH Centre for Energy Studies
Submitted in fulfilment of the requirements of the degree of Doctor of Philosophy
to the
Indian Institute of Technology, Delhi
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Dr. '.Tiwari Profe
Centre for Energy Studies Indian Institute of Technology Hauz Khas, New Delhi- 110016
CERTIFICATE
It is certified that the thesis entitled, "Heat and mass transfer for production of jaggery (Gur)" submitted by Om Prakash to Indian Institute of Technology, Delhi is worthy of consideration for the award of the degree of 'Doctor of Philosophy' and is a record of the original bonafide research work carried out by him under our guidance and supervision. The results contained in the thesis have not been submitted in part or full to any other University or Institute for the award of any degree or diploma.
Dr. Subodh Kumar Senior Scientific Officer Centre for Energy Studies Indian Institute of Technology Hauz Khas, New Delhi-110016
AC OWLEDGEMENTS
It is my immense pleasure to express the deep sense of gratitude to my supervisors, Prof. G.N. Tiwari and Dr. Subodh Kumar for their constant inspiring guidance and utmost co-operation at every stage that helped me in successful completion of this research work.
I am highly indebted to Prof. K.P. Mohammed, Ex- Head of Department Mechanical Engineering, Regional Engineering College Trichurappally. I am also grateful to Mr. Tangri, Head of Mechanical Engineering and Principal, Pusa Polytechnic Pusa, New Delhi for deputing me to pursue the Ph.D. programme at IIT, Delhi and their help rendered during the research work.
I am very much thankful to Prof. A. Chandra, Head, Prof. S.C. Kaushik, Prof.
L.M. Das and Prof. J.C. Joshi of Centre for Energy Studies for their kind advice and timely help. My sincere thanks go to Prof. V.K. Srivastava, Department of Chemical Engineering for their academic discussion and encouragement.
My special thanks go to my colleagues and to my friends Mr. B. Patak, Mr. S. K.
Dubay, Mr. Dal Jeet Khatri, Mr. Dilip Babu, Dr. Amita Gupta, Mr. Rajesh Tripathy, Mr.
Anil Kumar, Mr. Ravi Gupta, Anurag Sukla, G. S. Chaurasia, H. N. Singh, Dr. Sanjeev Kumar and Bikash Sarkar.
I have no befitting words to express my deep sentiments to my parents, brother S.
S. Chaurasia and other family members, my wife Anuradha Chaurasia, sons Ashish and Anurag Chaurasia for their wholehearted support and patience during the period of study.
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My wife joins me to extend our deep sense of obligation to Mrs. Tiwari and her children for their high degree of hospitality and encouragement throughout our study.
Last but not least, I convey my sincere thanks to Mr. Lalchmi Chand, Mr.Dhaney Singh, Mr. Shankar Lal, .Mr. Umesh Mishra and staff members of IIT, Delhi for their kind support and help in completing this research work.
Date Jun 17, 2004 (OM P' ASH)
ABSTRACT
The production of jaggery is a complex unit operation that involves simultaneous heat and mass transfer processes. The heat and mass transfer coefficients are the critical parameters, required in the solutions of various equations describing the modeling and computer simulation of simultaneous heat and mass transfer process. The production process of jaggery from sugarcane juice is a complex heating process that is occurred in two separate phases, namely sensible heating and pool boiling phases.
in the present thesis, the experimental study has been carried out for evaluation of heat and mass transfer during sensible heating and pool boiling of sugarcane juice for the preparation as well as drying of jaggery. The indoor sugarcane juice sensible heating experiments were performed both in open and close conditions. These conditions refer to heating of juice exposed/not exposed directly to the atmosphere respectively. The advantage with close syStem is that the evaporated water condensed at inner surface as fresh water in addition to increased evaporation rate. The effect of different rates of heating on mass of water evaporated for different amount of sugarcane juice indicate that the heat and mass transfer coefficients depend significantly on the rate of heating as well as heat capacity of sugarcane juice. The results of experiments on pool boiling of sugarcane juice show that the boiling heat transfer coefficient is significantly higher than that of sensible heating.
With the objective of reducing moisture content in jaggery for increased storage duration, the experiments were also performed to determine the heat and:mass transfer coefficients during drying of jaggery in natural and forced mode in controlled.
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environment using greenhouse test-model. It was found that the heat and mass transfer coefficients are strong function of mass of jaggery, temperature of greenhouse and relative humidity for a given size of greenhouse. The empirical expressions based on experimental results have been developed using for convective and evaporative heat and mass transfer coefficients as a function of jaggery temperature and drying time under natural and forced mode. The correlation coefficients, mean bias error, root mean square error have been obtained for confirmation of empirical relations.
TABLE OF CONTENTS
Page Certificate
Acknowledgements ii
Abstract iv
Table of contents vi
List of figures ix
List of tables xiv
Nomenclature xxiii
Chapter 4 General introduction 1-17
1.1 Introduction 1
1.2 Status of sugarcane 3
1.2.1 International status of sugarcane 3 1.2.2 National status of sugarcane 4
1.3 Products from sugarcane juice 6
1.4 Jaggery production process 8
1.5 Types of j aggery 12
1.5.1 Liquid j aggery 13
1.5.2 Solid j aggery 13
1.5.3 Powder j aggery 13
1.6 Medicinal properties 14
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1.7 Status of jaggery export 14
1.8 Identification of problem 15
1.9 Objective of the research 16
1.10 Approach 16
Chapter — 2 Evaluation of heat and mass transfer coefficients: sensible heating of
sugarcane juice 18-44
2.1 Introduction 18
2.2 Thermal modeling 19
2.3 Experimental setup and observations 20
2.4 Results and discussion 25
Chapter- 3 Evaluation of heat and mass transfer coefficients: pool boiling of sugarcane juice
3.1 Introduction
3.2 Experimental arrangement and procedure 3.3 Thermal analysis
3.4 Numerical computation and discussions
45-57 45 46 49 51
Chapter- 4 Evaluation of heat and mass transfer coefficients: drying
of jaggery 58-81
4.1 Introduction 58
4.2 Literature review 59
4.3 Methodology of jaggery drying 60 4.4 Design of experimental greenhouse and procedure 62
4.4.1 Experimental setup 62
4.4.2 Experimental observations 63
4.5 Thermal modeling 63
4.6 Results and discussion 65
Chapter- 5 Empirical expression for convective and evaporative heat transfer coefficients for the drying of jaggery 82-108
5.1 Introduction 82
5.2 Computation procedure 82
5.3 Results and discusSion. 106
Chapter — 6 Conclusions and recommendations 109-110
6.1 Conclusions 109
6.2 Recommendations 110
References 111-116
Appendices 117-118
Reprints/ preprints 119-123
Brief bio-data of the author 124
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