The Principle of Particle Settling in Motionless Fluid

ABSTRACT

Nowadays, the destruction and pollution of humane environment has produced an ever growing awareness worldwide of the need for more effective sedimentation processes. The main aim of this project was to design and fabricate an experimental sedimentation rig with the objective to determine the rate of settling against time using calcium carbonate as a test sample.The rig consists mainly of the cylindrical tank, valves, motor, stirrer, and the sight glass. For the test run, 82 litres of water and500g of calcium carbonate was introduced into the tank,stirred andwas let tosettle under gravity. The settled height was observed with time at time intervals of 60 seconds,it could be observed that the calcium carbonate settles at different height of 115, 110.5, 104.6, 99.3, 92.5, 85.7, 77.5, 68.3, 60.1, 52.5, 42.3, 33.4, 20.6 and 10.8cm considering the settling behavior. The settling velocity and Reynolds number of flow gotten was 15.42cm/min and 84.5respectively. It could be concluded from the experiment conducted with the rig thatthe higher the concentration is the quicker the sedimentation process is done quickly and the rig could be recommended for waste water industries to study rate of settings of sediments of different particulate distribution from fluids.

TABLE OF CONTENTS

CONTENTSPAGE

Cover pagei

Title Pageii

Declarationiii

Certificationiv

Dedicationv

Acknowledgementvi

Abstractvii

Table of Contentsviii

List of Figures 

CHAPTER ONE: INTRODUCTION

1.1Background of Study1

1.2Statement of Problem2

1.3Aims and Objectives2

1.4Significance of Study2

1.5Scope and Limitations of Study3

1.6Definition of Terms3

CHAPTER TWO: LITERATURE REVIEW

2.1Theory of sedimentation5

2.2Application Of sedimentation Process6

2.3Factors Affecting Sedimentation6

2.3.1 Particle Size6

2.3.2Temperature7

2.3.3Currents7

2.4Sedimentation Basin Zones7

2.4.1Inlet Zone8

2.4.2Settling Zones8

2.4.3Sludge zone8

2.4.4Outlet Zone8

2.5Settling Velocity Theory9

2.5.1Stokes Law9

2.5.2Newton’s Law of Sedimentation/Settling10

2.6Context11

CHAPTER THREE: METHODOLOGY

3.1Selection of Materials13

3.2Basic Design Requirements13

3.3Design Details14

3.4Sediment Introduction and Outlet System14

3.5Materials and Equipment Used14

3.5.1Materials Used14

3.5.2Equipment Used19

3.6Fabrication of Apparatus24

3.7Cost Estimation27

3.8Project plan28

CHAPTER FOUR: RESULTS AND DISCUSSION

4.1Results29

4.2Discussion32

CHAPTER FIVE: CONCLUSION AND RECOMMENDATIONS

5.1Conclusion34

5.2Recommendations34

REFERENCES36

LIST OF FIGURES

Figure 2.1: Free Body Diagram of a discrete particle5

Figure 2.2: Current flow in feed7

Figure 2.3: Settling Zones8

Figure 3.1: Mild steel15

Figure 3.2: Stirrer16

Figure 3.3: Electric Motor17

Figure 3.4: Rollers or casters17

Figure 3.5: Valve18

Figure 3.6: Tape rule19

Figure 3.7: Drilling Machine20

Figure 3.8: Hammer20

Figure 3.9: Cutting Machine21

Figure 3.10: File21

Figure 3.11: Plate rolling machine22

Figure 3.12: Welding machine22

Figure 3.13: Spray paint machine23

Figure 3.14: AutoCAD diagram of apparatus24

Figure 3.15: Picture of fabricated apparatus25

Figure 3.16: Labeled diagram of apparatus and P&ID diagram26

Figure 4.1: Graph of Clear Height against Time31