Review on densification of palm residues as a technique for biomass energy utilization

Due to the tremendous amount of palm biomass residues produced during the palm oil extraction from fresh fruit bunch (FFB), it is inevitable to harness these biomass energy sources to cope with the depletion of fossil fuels and increase in global energy demand scenarios. Densification is one of the favourable techniques to improve the storage and transportation of biomass fuels in order to prevent dumped areas adjacent to palm mills and to prevent from becoming another waste product. This article reviews comprehensively on how type of palm biomass, compaction pressure and temperature, binder, pre- and post-treatments affect the physical and combustion properties of the palm biomass briquettes produced. Based on the previous researches, generally it can be said that the type of palm biomass, the compaction pressure and temperature, and type of binder affect both the physical and combustion performance of densified palm biomass. However, the effect of particle size could be observed only on the physical characteristics of densified products, whereas the effect on the combustion properties remains unclear. In addition, treatments such as pyrolysis, dry and wet torrefaction (hydrothermal treatment), and steam explosion have potential to be applied during briquette production in order to improve the combustion properties. In this review article, it is also suggested that the combination of densification and followed by wet torrefaction will enhance the combustion properties of palm biomass briquette

Sugar palm (Arenga pinnata): Its fibres, polymers and composites.

Sugar palm (Arenga pinnata) is a multipurpose palm species from which a variety of foods and beverages, timber commodities, biofibres, biopolymers and biocomposites can be produced. Recently, it is being used as a source of renewable energy in the form of bio-ethanol via fermentation process of the sugar palm sap. Although numerous products can be produced from sugar palm, three products that are most prominent are palm sugar, fruits and fibres. This paper focuses mainly on the significance of fibres as they are highly durable, resistant to sea water and because they are available naturally in the form of woven fibre they are easy to process. Besides the recent advances in the research of sugar palm fibres and their composites, this paper also addresses the development of new biodegradable polymer derived from sugar palm starch, and presents reviews on fibre surface treatment, product development, and challenges and efforts on properties enhancement of sugar palm fibre composites

Combustion characteristic inside micro channel combustor

Small-scale electronic devices require long hours’ operation and fast charging time. Potential technology to support requirement of small-scale electronic device is micro scale combustor. Unfortunately, micro scale combustion is prone to combustion instability. Therefore, objective of this study is to investigate the combustion characteristics, mechanism that stabilize the flame and combustor performance of the 2-D microchannel combustor with bluff body having various slit percentages gap. Two-dimensional computational domain with the height and length of the channel H = 1 mm and L = 16 mm is used respectively. The height of the bluff body is 0.5 mm and located at 2 mm from the inlet. The slit gap percentage varied in this study is 0% to 70%. The results show that the combustion characteristic such as stable flame, wavy flame, blow-off, and flame split into two parts is significantly influenced by the slit gap percentage. Flame is moving downstream and blow-off at the slit percentage of 10% to 25%. At the slit percentage of 30%, the flame zone moves towards the upstream due to the secondary vortex that exists behind the bluff body as slit gap increases and pushes the flame upstream. The reaction zone is split into two parts at 60% and 70% slit gap percentage. It is due to the incoming fresh mixture of CH4/air mixture flows through the slit and cuts the flame zone. It is also found that by increasing inlet velocity beyond 2.0 m/s, the flame becomes unstable and leads to blow-off as increase in equivalence ratio up to 1.0

Torrefaction of oil palm frond petiole: effect of particle sizes, sections and batches

This study aimed to investigate the effect of batches (1, 2 and 3), particle sizes (<250 µm, range of 300 µm to 500 µm), and sections (bottom, middle and top) on combustion performance of the oil palm frond (OPF) petiole after torrefaction at 275 °C. The higher heating value (HHV), mass yield, energy yield, HHV yield and proximate analyses of the untorrefied and torrefied OPF petiole for all cases were determined. The comparison between the untorrefied and torrefied OPF petiole as well as an international benchmark was also performed. In this study, the highest HHV of the torrefied OPF petiole (22.85±0.07MJ/kg) was obtained at the bottom section with the particle size of < 250 µm. Furthermore, the fixed carbon content of the torrefied OPF petiole increased, whereas the volatile matter, moisture content, mass and energy yields decreased for all cases after torrefaction. HHV yield of OPF petiole was recorded up to 141% after torrefaction. The ash content was sufficiently satisfied the international benchmark for most cases, except for top section (300-500µm). The changes in combustion properties of the torrefied OPF petiole for all cases were found to be insignificant whereas significant improvement could be observed when compared to untorrefied OPF petiole. Overall, the study revealed that the appropriate particle size for torrefaction can promote it to be a vital source for energy production from oil palm biomass

Investigation on the mass burning rate of biodiesel blended with ethanol subjected to cross airflow

Burning rates of the biodiesel B7 and blended with 10 %vol. and 15 %vol ethanol in 50 mm diameter of pan were investigated. Angle of the pan wall was set to 0 deg. and 60 deg. and 1 m/s to 3.5 m/s of longitudinal air, flows across the pan. Results show that, as increase in the longitudinal airflow speed, the burning rates of biodiesel B7+15 %vol ethanol increased, but it decreased for the biodiesel B7 and biodiesel B7+10 %vol. ethanol. Moreover, burning rate of 0 deg. is higher than that 60 deg. for all cases. It is concluded that for the case of biodiesel B7+15 %vol ethanol, incoming air helps in increasing the burning rate. But for biodiesel B7 and biodiesel B7+10 %vol. ethanol, the incoming air reduces the pan temperature and leads to low burning rate. Furthermore, 0 deg. case gives a higher burning rate for all fuels because flame tilt significantly and increased the rate of heat transfer by conduction and radiation from the flame to the fuel. The 60 deg. case showed that flame is less tilted thus leads to less burning rate