Research and Simulation on Biomass Energy Generation System

Swinburne University of Technology

 Sarawak Campus

School of Engineering and Sciences

Research and Simulation on Biomass

Energy Generation System

Bachelor of Engineering

(Mechanical)

[pic 1]

Marco Tan Wai Lam (4201558)

Dec/2011

Declaration

We hereby declare that this report entitled “Research and Simulation on Biomass Energy Generation System” is the result of our own project work except for quotations and citations which have been duly acknowledged. We also declare that is it has not been previously or concurrently submitted for any other degree at Swinburne University of Technology (Sarawak Campus).  

Name:         Marco Tan Wai Lam        

ID:         4201558                

Date:        2 December 2011                

Abstract

Biomass is a promising green energy of the future and should be develop further. However, the design of the gasifiers affecting the heat profile and the air flow inside the gasifier is still not well understood and developed as this will affect the efficiency of the system. The efficiency of the gasifier is affected by a few factors such as air-to-fuel ratio, temperature of the process zone and air flow of the supplied gas in the gasifier.

This paper will be focusing mainly on the heat profile and the air flow of updraft and downdraft fixed-bed gasifier. Continuity and energy equations were used to determine certain parameters for the gasifiers which will then be set as the boundary conditions for the modeling. The simulation of the gasifiers will be done with CFD (Computational Fluid Dynamics) using SolidWorks flow simulation.

Acknowledgement

The author would like to thank Dr. Ha How Ung and Dr. Almon Chai for supervising, guiding and providing feedbacks during the whole duration of the project.

Table of Contents

Declaration        

Abstract        

Acknowledgement        

1. Introduction        

1.1 Thermochemical Conversion        

1.2 Types of Gasifier        

1.2.1 Fixed/Moving Bed Gasifier        

1.3 Objectives        

2. Literature Review        

2.1 Downdraft Gasifier        

2.2 Updraft Gasifier        

2.3 Tar Reduction        

2.3.1 Addition of Air Injection        

2.3.2 Recirculation of Pyrolysis Gas        

2.3.3 Modification of Gas Outlet        

2.3.4 Modification of Combustion Zone Position        

2.3.5 Separation for Pyrolysis and Reduction into Different Chambers        

2.3.6 Application of Catalytic Bed        

3. Methodology        

3.1 Numerical Method        

3.2 Gasifier’s Information        

3.3 Boundary Conditions for Simulation        

4. Results        

4.1 Experiment        

4.2 Simulation        

5. Discussion        

References        

List of Figures and Tables

Figures

Figure 1. Examples of Biomass        

Figure 2. Updraft Gasifier        

Figure 3. Downdraft Gasifier        

Figure 4. Composition Variation across the Length in the Reduction Zone (fp = 0.2)        

Figure 5. Composition Variation across the Length in the Reduction Zone (fp = 0.25)        

Figure 6. Source Rate Profiles with Various Oxygen Concentrations        

Figure 7. Outlet Mass Flow with respect to Time        

Figure 8. Two Stage Throatless Downdraft Gasifier        

Figure 9. Throat-less Downdraft Gasifier        

Figure 10. Twin Fired Gasifier        

Figure 11. DelaCotte Tar Recycling Gasifier        

Figure 12. Two Stage Updraft Gasifier        

Figure 13. Updraft Fixed Bed Gasifier with Embedded Combustor        

Figure 14. Top Lit Updraft Gasifier        

Figure 15. Two Stage Gasifier        

Figure 16. Three Stage Gasifier        

Figure 17. Two Stage Updraft Gasifier        

Figure 18.  Principle of Operation of Belonio's Gasifier        

Figure 19.Velocity Profile of Updraft with Air Volume Flow Rate of 0.004m3/s        

Figure 20. 3-D Velocity Profile of Updraft with Air Volume Flow Rate of 0.004m3/s        

Figure 21. Temperature Profile of Updraft with Air Volume Flow Rate of 0.008m3/s        

Figure 22. Velocity Profile of Updraft with Air Volume Flow Rate of 0.008m3/s