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)

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Prepared by

Howard Woo 4207505

May 2011

Declaration

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

Name:         Howard Woo

ID:        4207505        

Date:        15 May 2011                

Table of Contents

Declaration        

Table of Contents        

List of Tables and Figures        

Acknowledgement        

1        Abstract        

2        Introduction        

2.1        Biomass fuel        

2.2        Biomass conversion process        

2.3        Gasifier        

2.3.1        Gasifier types        

2.3.2        Updraft gasifier        

2.3.3        Downdraft gasifer        

3        Literature review        

3.1        Biomass as fuels        

3.2        Optimization of gasifier system        

3.3        Modelling for gasifier        

3.4        Case studies        

3.4.1        Updraft gasifier        

4        Methodology        

4.1        Approach 1: Comparison of airflow in updraft and downdraft gasifier model        

4.1.1        Chemical reaction        

4.1.2        Formulation of theory – Fluid dynamics and Thermodynamics        

4.1.3        Geometry and Boundary Condition        

4.1.4        Numerical solution and computational analysis        

5        Discussion and future work        

6        References        

7        Appendices        

List of Tables and Figures

Figure 21 Comparison between biochemical process and thermochemical conversion process        

Figure 22 Comparison of four major thermochemical conversion process (source: adapted from Demirbas, 2009)        

Figure 23 Diagram of updraft gasification (source: Skov 1974)        

Figure 24 Diagram of downdraft gasification (source: Skov 1974)        

Figure 31 Example result for influence of drying agent in gasification        

Figure 32 Concentration of gaseous products and temperature profile of 2kg wood pellets, with air flow rate: a) 2m³/h and b) 1.1 m³/h        

Figure 33 Concentration of gaseous products and temperature profile of a) 4 kg and b) 3 kg wood pellets with air flow rate of 2 m³/h.        

Figure 34 Concentration of gaseous products and temperature profile of a) 4 kg and b) 3 kg wood pellets with air flow rate of 1.5 m³/h.        

Figure 35 Concentration of gaseous products and temperature profile of a) 4 kg and b) 3 kg wood pellets with air flow rate of 1.5 m³/h.        

Figure 36 Concentration of gaseous products and temperature profile of 4 kg wood pellets with air flow rate of 2.6 m³/h.        

Figure 37 Liquid product (tar + water) obtained from 3 kg and 4 kg wood pellets.        

Figure 41Example dimensioning of gasifier - Imbert design gasifier diameter and Hearth diameter        

Figure 42 Notation for formulas and equations of modelling        

Figure 61Example result for updraft gasifier from Di Blasi’s ‘Modelling wood gasification in a countercurrent fixed-bed reactor        

Figure 62 Calorific Values of different compounds        

Figure 63 Phase diagram showing the relative proportions of carbon, hydrogen, and oxygen in solid, liquid, and gaseous fuels (source: Reed 1981)        

Figure 64 Chemical changes during biomass conversion processes        

Table 1 Moisture content, gross calorific value, net calorific value, bulk density and energy density of biomass fuels (source: Van Loo 2008)        

Table 2 N, S, and Cl concentrations in biomass fuels (source: Van Loo, 2008)