This project study was aimed at designing, fabricating, and evaluating the performance of a double effect evaporator, which was used to evaporate sugar syrup to be used for students’ demonstration. During the course of the study, the methods that were used comprised of the material balances, energy balances, and determination of the component parts of the evaporator. The results from the study included the overall material in the evaporator’s system, the material balance for each effect, the effect heat duties and required heat transfer areas, the temperatures for each effect, and the equipment specifications. A feed flow rate of 0.63kg/s was used which produced a product having a flow rate of 0.593kg/s with the total water evaporated as 0.037kg/s. It was discovered that the solid compositions of feed increased across each effect, from 0.725 to 0.745 to 0.77 solid composition, while the feed flow rate across each effect reduced from 0.63 kg/s to 0.613 kg/s to 0.593kg/s. Reduction in heat duties from 79.3KW to 37.8KW were obtained across each effect, which subsequently gave a reduction of heat transfer areas across each effect as 0.005m2 and 0.003m2. The temperatures of the products, exiting effects 1 and 2 were given as 112°C and 98.22°C respectively, which lead to a decrease in steam saturation temperatures from its initial temperature at 120°C to 107.22 to 93.16°C. This also lead to an increase in boiling points of the products from 4.78°C to 5.06°C. An overall steam economy of 1.03kg of water vaporized per kg of steam consumed was obtained, as well as the capacity which was obtained as 133.2kg of water vaporized per hour. From the study, it was concluded that the equipment was capable of utilizing the steam that is being fed into the double effect evaporator, thereby managing cost and time. At the end of the experiment, it is advised that more effects should be added to the system, other types of feed arrangements should be tested to determine its efficiency.
Keywords: double effect evaporator, sugar slurry, sugar
TABLE OF CONTENTS
Dedication ii
Acknowledgement iii
Abstract iv
Table of ContentS v
LIST OF TABLES ix
LIST OF FIGURES x
NOMENCLATURE xi
CHAPTER ONE
1.0 Introduction 1
1.1 Background of the Study 1
1.2 Statement of the Problem 3
1.3 Aim and Objectives 4
1.4 Scope of Study 4
1.5 Significance of the Study 5
CHAPTER TWO
2.0 Literature Review 6
2.1 Design 6
2.1.1 Design as a Process 6
2.1.1.1The Rational Model 7
2.1.1.2The Action-Centric Model 9
2.1.2 Descriptions of Design Activities 9
2.1.3 Methods of Designing 10
2.1.4 Design and Engineering 11
2.1.5 Design and Production 11
2.1.6 Process Design 12
2.2 Metal Fabrication 13
2.2.1 Processes 13
2.2.2 Raw Materials 15
2.2.3 Cutting and Burning 15
2.2.4 Forming 16
2.2.5 Machining 16
2.2.6 Welding 16
2.2.7 Final Assembly 17
2.3 Performance Evaluation 17
2.3.1 Performance Evaluation Process 18
2.3.2 Performance Evaluation Methods 19
2.4 Theory of Evaporation 21
2.4.1 Factors Affecting Evaporation 23
2.5 Evaporators 23
2.5.1 How an Evaporator Works 23
2.5.2 Evaporator Operation 24
2.5.3 Uses of Evaporators 25
2.5.4 Energetics of Evaporators 27
2.5.5 Selection of Evaporators 28
2.5.6 Types of Evaporators 29
2.5.6.1Short-Tube Vertical Evaporator 30
2.6.6.2Basket-type Vertical Evaporator 30
2.5.6.3Long-Tube Vertical Evaporator 31
2.5.6.4Falling Film Evaporator 31
2.5.6.5Rising or Climbing Film Evaporator 31
2.5.6.6Forced Circulation Evaporator 32
2.5.6.7Agitated Thin Film Evaporator 33
2.5.6.8Gasketed-Plate Evaporator 33
2.5.7 Performance of Steam Heated Tubular Evaporators 33
2.5.7.1Capacity and Economy 33
2.5.8 Boiling Point Elevation 34
2.6 Single and Multiple Effect Evaporators 35
2.6.1 Multiple-Effect Evaporator 38
2.6.1.1Thermal Design Calculations for the Design of 40
a Multiple-Effect Evaporator
2.7 The Use of Stainless Steel in the Design of Evaporators 45
2.7.1 Identification 45
2.7.2 General-Purpose Stainless Steels 47
2.7.3 Guidelines for Selection 48
CHAPTER THREE
3.0 Materials and Methods 49
3.1 Materials 49
3.2 Methods 49
3.2.1 Mathematical Methods 49
3.2.2 Design of Components of the Machine 57
3.2.3 Mechanical Methods 61
3.3 Safety Consideration 63
CHAPTER FOUR
4.0 Result and Discussion 64
4.1 Result 64
4.1.1 Result of the Material Balance Summary of the Evaporator 64
4.1.2 Result of the Energy Balance Summary of the Evaporator 64
4.1.3 Result of the Equipment Specifications Summary 65
4.2 Discussion 65
CHAPTER FIVE
5.0 Conclusion and recommendation 69
5.1 Conclusion 69
5.2 Recommendation 69
References
APPENDIX
Appendix 1: Material Balance Calculations
Appendix 2: Energy Balance Calculations
Appendix 3: Equipment Specifications Calculations
Appendix 4: Cost of Materials