Optimization of torrefaction conditions for high energy density solid biofuel from oil palm biomass and fast growing species available in Malaysia

Abstract

Without appropriate treatment, lignocellulosic biomass is not suitable to be fed into existing combustion systems because of its high moisture content, low bulk energy density and difficulties in transport, handling and storage. The aim of this study was to investigate the effects of torrefaction treatment on the weight loss and energy properties of fast growing species in Malaysia (Acacia spp., and Macaranga spp.) as well as oil palm biomass (oil palm trunk and empty fruit bunch). The lignocellulosic biomass was torrefied at three different temperatures 200, 250 and 300 °C for 15, 30 and 45 min. Response surface methodology was used for optimization of torrefaction conditions, so that biofuel of high energy density, maximized energy properties and minimum weight loss could be manufactured. The analyses showed that increase in heating values was affected by treatment severity (cumulated effect of temperature and time). Our results clearly demonstrated an increased degradation of the material due to the combined effects of temperature and treatment time. While the reaction time had less impact on the energy density of torrefied biomass, the effect of reaction temperature was considerably stronger under the torrefaction conditions used in this study. It was demonstrated that each biomass type had its own unique set of operating conditions to achieve the same product quality. The optimized torrefaction conditions were verified empirically and applicability of the model was confirmed. The torrefied biomass occurred more suitable than raw biomass in terms of calorific value, physical and chemical properties. The results of this study could be used as a guide for the production of high energy density solid biofuel from lignocellulosic biomass available in Malaysia.

Torrefaction of oil palm frond: The effect of process condition to calorific value and proximate analysis

“…The HHV significantly increased with torrefaction temperature than reaction time. This tendency is consistent with the previous work [7,9], and is mainly due to the carbon content increase meanwhile the oxygen and hydrogen decrease. This decrease in hydrogen and oxygen is due to dehydration and de-carbondioxide from the biomass during torrefaction [10].…”

“…Decreasing of hemicellulose and volatiles will increase calorific value and maximize mass yield and energy yield from solid product [5][6][7][8] Uemura et al [5] torrefied empty fruit bunch at 225-275 °C and stated that temperature played a significant role toward solid product. Chin et al [7] investigated OPT at 200-300 °C for 15-45 minutes. They found that time also affected torrefaction but was not as signifant as temperature.…”

Valorization of Waste Wood as a Solid Fuel by Torrefaction

“…Various works have shown that the effect of torrefaction temperature has a more pronounced effect than residence time, for instance, Chin et al [28] concluded that although the GCV (MJ/kg) increased with both residence time and temperature, the value was more influenced by torrefaction temperature. In contrast, the present study has found that the overall increase in the GCV (MJ/kg) is comparable for both temperature and residence time.…”

Bioenergy Production from Bamboo: Potential Source from Malaysia’s Perspective

“…degraded and the nature of the resulting product was between that of lignocellulose and charcoal (Chin et al 2013b). Hernández-Mena et al (2014) studied the effect of slow pyrolysis on the biochar properties of bamboo (Dendrocalamus giganteus Munro).…”

“…Bamboo torrefied under carbon dioxide atmosphere at 240 to 340 °C, obtained solid products with mass yield 41 to 97%, energy yield 63 to 99%, and HHV 18.78 to 28.51 MJ/kg (Li et al 2015a). Bamboo is extremely high in lignin content (29 to 46%), and this makes it a desirable species for solid biofuel production, as a high lignin content in the torrefied biomass results in a higher HHV (Chin et al 2013b). Co-firing with bamboo by replacing up to 30% of the coal requirements has been shown to be economical and is a promising environmentally friendly technology (Chao et al 2008).…”