1. Characterization of torrefied sugarcane bagasse for gasification in a downdraft biomass gasifier system. A I Anukam, S N Mamphweli, P Reddy, E L Meyer and O Okoh University of Fort Hare, Institute of Technology

2. 2 OUTLINE Energy from biomass Gasification overview Problem statement Aims and objectives Research approach Results Conclusions

3. ENERGY FROM BIOMASS Bioenergy remains an important source of energy 20/06/20063 Bioenergy production GASIFICATION

4. 4 Gasification is a thermal decomposition process that breaks down any carbon-containing material into its basic chemical constituents, collectively known as syngas. GASIFICATION OVERVIEW Syngas production

5. 5 GASIFICATION PROCESS The downdraft gasifier Drying zone Distillation zone Reduction zone Combustion zone Ash grate Ash pit Gas out Fuel

6. CHALLENGES OF USING BIOMASS Low energy density Low bulk density High moisture content High mineral matter content Heterogeneous shape/size Irregular physical and chemical properties 20/06/20066 Quality issues

7. 7 Thermal treatment of a material between 200 – 300 ° C [Luo, 2011]. Makes the material undergo Maillard reaction [Bergman et al., 2005]. Improves feedstock properties for energy production. BIOMASS PRE-TREATMENT PROCESSES Torrefaction Non – enzymatic browning

8. 20/06/20068 Gasification efficiencies have always fallen below those of equivalent fossil – fired systems due to reduced gasification conditions enforced by severe fouling and corrosion problems experienced as a result of high level of impurities posed by inefficient pre-processing of bagasse before conversion into energy. There is an increased degree of complexity involved in the efficient pre-processing of sugarcane bagasse before gasification begins, given its high complex structure and chemical makeup. PROBLEM STATEMENT

9. 9 AIMS & OBJECTIVES Aim To investigate the torrefaction characteristics of sugarcane bagasse for the purpose of gasification in a downdraft system in order to establish the impact of thermal treatment on the properties of bagasse and on the conversion efficiency of its gasification process under standard gasifier operating conditions. Objectives To conduct torrefaction of sugarcane bagasse at specific temperature To characterize the torrefied bagasse in terms of proximate and ultimate analyses as well as in terms of energy value. To conduct computer simulation of the gasification process of torrefied bagasse.

10. 10 RESEARCH APPROACH Torrefaction process of bagasse Experimental set-up for torrefaction [Luo, 2011] Sample holder [Luo, 2011]

11. 11 EXPERIMENTAL Material characterization

12. COMPUTER SIMULATION A gasification simulation program – developed by Chen et al., 1986 and modified by Jayah et al., 2003. 20/06/200612 Gasification simulation (1.1) (1.2)

13. OPERATING CONDITIONS 20/06/200613 Fuel properties ValueGasifier operating conditionsValue Carbon (%)47.62Throat diameter (cm)25.5 Hydrogen (%) 4.43 Throat angle ( ° ) 90.0 Oxygen (%) 41.32Insulation thickness (cm)17.5 Nitrogen (%)0.29Thermal conductivity (W/cm K)2.80 Fixed carbon (%)31.52Temperature of input air (K)300 Bulk density (g/cm 3 )0.178Air input (kg/hr)44.5 Diameter of particle (cm) 14.30Heat loss (%)12.8 Moisture content (%) 4.80Feed input (kg/hr) 40 Table 1: Standard operating conditions of a downdarft gasifier [Jayah et al., 2003]. Standard conditions

14. 14 RESULTS Torrefaction behaviour Bagasse before torrefactionBagasse after torrefaction

15. 15 PROPERTIES OF BAGASSE Proximate & Ultimate analyses Figure 9. Proximate analysis of torrefied bagasse. Figure 10. Ultimate analysis of torrefied bagasse.

16. 16 THERMAL PROPERTIES Thermal behaviour of TB Figure 11. Mass loss with temperature during TG analysis of TB Figure 12. Mass loss with time during TG analysis of TB

17. SIMULATION RESULTS 20/06/200617 Conversion efficiency Figure 13. Simulation of the conversion efficiency of the gasification process of torrefied bagasse

18. CONCLUSIONS 20/06/200618 The study established that torrefied bagasse is a carbonaceous feedstock suitable for gasification in a downdraft system properly designed to accommodate the properties of the feedstock.

19. 20/06/200619 THANK YOU