ENEM20003 Thermofluids Engineering Applications

ENEM20003: Thermofluids Engineering Applications
Term 1, 2020
Project Report
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School of Engineering and Technology
Central Queensland University
Australia

Executive Summary
It is essentially important to understand the processes of aluminum production from
its ore, Bauxite. This is achieved by two processes, Bayer and Hall-Heroult, developed in the
late ’80s by Josef Bayer and Hall in Austria. The Bayer process involves three processes to
produce alumina oxide. These processes are; digestion, clarification, precipitation, and
calcination. During digestion, the ore is crushed into small powder particles and dissolved in
sodium hydroxide solution at around 175 degrees Celsius. In clarification, the solids settle
and are removed. In the precipitation stage, the alkaline slurry is cooled to around 32 degrees
Celsius where alumina hydroxide precipitates out. This process involves agitation, cooling,
and seeding. In the final stage, calcination, the solution is heated to give off moisture to
produce aluminum oxide powder which is transported to the Hall-Heroult plant or other uses.
Ideally, 2 kgs of bauxite produce at least 1.5 kg of pure aluminum (Parfenov et al 2016). This
process is represented in the flow diagram below.
Figure 1: Bayer process
The alkaline liquor is after this process is transported to a thickening tank from where
excess solids settle. The clarified slurry is transported to the precipitation tank before being
sent to the tertiary tank. The three tanks are spaced as follows; 200m between thickening and
precipitation tank and 800m between precipitation tank to the tertiary tank.

Declaration of Contribution
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Table of Contents
Executive Summary...................................................................................................................2
Declaration of Contribution.......................................................................................................3
Table of Contents.......................................................................................................................4
List of Figures............................................................................................................................5
List of Tables..............................................................................................................................6
List of Abbreviations and Acronyms.........................................................................................7
PART A: General (10 marks)......................................8
A.1 Introduction, aim, and objectives of the project..............................................................8
A.2 Brief literature review relevant to this project................................................................9
A.3 Brief description of related systems..............................................................................10
A.4 Assumptions and data presentation...............................................................................11
A.5 Academic writing and Referencing...............................................................................11
PART B: Pump system design and calculation (50 marks).......................................12
B.1 Project schematic showing relevant components (front and top use CAD)..................12
B.2 Fittings ∑KL values Tables for the full plant pipeline..................................................13
B.3 Pipe material, diameter (I/O), busting pressure, friction factor (f) for entire system
including precipitation tank C.2...........................................................................................14
B.4 System equation (static head, dynamic head, and head loss) for Thickening Tank pump
P-101....................................................................................................................................15
B.5 Duty point (DP) of the feed pump for Thickening Tank P101......................................16
B.6 Pump characteristics at DP (head, power, efficiency, specific speed, etc.)..................17
B.7 Draw velocity triangles for inlet and outlet of the pump impeller................................18
B.8 Calculate theoretical head (H), power and compare with DP values............................19
B.9 Cavitation check (NPSHA) for feed pump P-101.........................................................20
B.10 Apply similarity laws for Precipitation & Tertiary pumps P102, P103......................21
B.11 Analyse CH, CP vs CQ at a fixed speed for P-102, P-103 separately........................22
B.12 Cavitation check (NPSHA) for all Tank pumps..........................................................23
B.13 Calculate total power cost per day for running all pumps (show in a Table)..............25
PART C: Precipitation tank design (scaling & agitation system) (15 marks)..........26
C.1 Brief literature on scaling and scale mitigation.............................................................26
C.2 Detail design of a simplified agitator system in the precipitation tank.........................27
C.3 Analysis of velocity and power required for scale suppression....................................29

D.1 General description and assumption for rheometer design...........................................30
D.2 Design/schematics and theory.......................................................................................31
D.3 Location of installation and soundness of the operation)..............................................32
PART E: Alternate transportation system design (5 marks).........................................33
E.1 General discussion on the type of transportation...........................................................33
E.2 Schematics and operating principles.............................................................................34
E.3 Justification/comparative assessment with the existing method...................................35
PART F: Others (10 marks).....................................36
F.1 Conclusion and recommendations.................................................................................36
References............................................................................................................................37

List of Figures
Figure 1: Process Flow Schematic...........................................................................................13
Figure 2: K-Factors (Source: Janna, 2014)..............................................................................14
Figure 3: Duty Points (Source, Grundfos.com).......................................................................17
Figure 4:Pump Curves (Source: Grundfos.com)......................................................................18
Figure 5: Velocity Diagram.....................................................................................................19
Figure 6:Pump Curves (Source: Grundfos.com)......................................................................20
Figure 7: Pump Curves (Source: Grundfos.com).....................................................................21
Figure 8: Pump Schematic.......................................................................................................23
Figure 9:Pump Curves (Source: Grundfos.com)......................................................................24
Figure 10:Pump Curves (Source: Grundfos.com)....................................................................25
Figure 11:Swirl agitator...........................................................................................................28
Figure 12:Agitation schematic.................................................................................................28
Figure 13:Rheometer Schematic..............................................................................................32
Figure 14: Alternative schematic.............................................................................................35

List of Tables
Table 1: K-Factors for Various Fittings...................................................................................16

List of Abbreviations and Acronyms
PVC- Poly Vinyl Chloride
NPSH-Net Positive Suction Pressure
V-Velocity
g-Gravity
D-Diameter
H-Head
Q-Flow rate
f-Friction factor