Engineering HDR Seminar Series 20, 2011: Upgrading of Biomass Properties via Torrefaction

Ms Chew Jiuan Jing, CSPE postgraduate student

Date: 2011-12-15
Time: 12:00 to 13:00
Venue: Classroom 9-3-03


Biomass derived from oil palm waste, to a large extent has been used for power generation in palm oil mills via combustion and gasification. Characteristics of biomass such as poor combustion characteristics, low heating value, hygroscopic nature, and difficulty in grinding renders the utilization of biomass as feedstock limited and complex. In this research work, it is proposed that the introduction of a pre-treatment process known as torrefaction be used to upgrade the oil palm biomass quality. Torrefaction is a pre-treatment process performed at temperatures of 200-300ºC in the absence of oxygen. This research work looks into the possibility of torrefaction of oil palm biomass using a laboratory scale fixed bed reactor with process parameter optimization in mind. The effect of torrefaction parameters such as raw material, temperature and residence time on the torrefied product yield is examined. For better understanding on the changes introduced by torrefaction, both the treated and untreated biomass were characterized using analytical studies such as proximate analysis, ultimate analysis, and calorific value. The changes in palm waste characteristics were evaluated and used as indications of the effectiveness of the torrefaction process. Consequently, the optimum operating conditions that produced the best palm waste characteristics is identified. In the study, oil palm biomass attains hydrophobic property and moisture content of torrefied biomass can be maintained below 10%. Mass yield of torrefied product decreases with the severity of torrefaction parameter. After torrefaction, the calorific value of palm wastes increases and the waste samples became more alkaline and easier to grind. The noted improvement in calorific values indicated improvement in properties of palm waste as a solid fuel. The amount of torrefied palm waste needed will be less than the original amount of untreated palm waste used to produce the same amount of energy. More importantly, decreased particle size and reduced fibrous characteristics are particularly the key features sought after because this feature will improve handleability which is vital for machine processing and logistics purposes.

About the Speaker

Ms Chew completed her undergraduate studies in Chemical Engineering in Curtin University of Technology. Joined Monash University in 2010 for postgraduate studies under the supervision of Dr Veena Doshi. Currently in 2nd year of PhD research undertaking the project title "Pre-treatment of local biomass for higher energy recovery and process stability during gasification and combustion".