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Abstract: Torrefaction of oil palm empty fruit bunches (EFB), waste products from the palm oil industry, was carried out in a fixed-bed tubular reactor in the presence of oxygen at concentrations ranging from 0% to 15%. The effects of oxygen concentration (0%, 3%, 9% and 15%), temperature (493, 523 and 573K) and biomass size (0.375, 1.5, 3 and 6mm) on the torrefaction mass and energy yields were investigated. The mass yield decreased with increasing temperature and oxygen concentration, but was unaffected by biomass size. The energy yield decreased with increasing oxygen concentrations, but was still between 85% and 95%. The energy yield showed concave profiles with increasing temperature. Mechanistically, it was found that the ‘oxidative torrefaction’ process occurred in two successive steps or via two parallel reactions, where; one reaction is ordinary torrefaction, and the other is oxidation. Analysis of the reaction kinetics based on the suggested mechanisms produced an activation energy of torrefaction, that was consistent with previous studies. [Copyright &y& Elsevier]

Abstract: This paper describes the effect of torrefaction on the basic characteristics of agricultural biomass wastes in Malaysia, such as empty fruit bunches (EFB), mesocarp fiber and kernel shell as a potential source of solid fuel. Mesocarp fiber and kernel shell exhibited excellent energy yield values higher than 95%. EFB, on the other hand, exhibited a rather poor yield of 56%. [Copyright &y& Elsevier]

Abstract: A room-cooling system of 2kW capacity fueled by wood pellets was designed, built and tested. The system was demonstrated during summer at the Yakushima Field Station of Kagoshima University, Japan. It contained a pellet feeder, a pellet burner, a heat exchanger, a lithium bromide–water absorption heat pump and a control unit. The volume of the test room was 36.9m3 and ambient temperature 30°C. The airflow temperature from the room unit was decreased to 16°C by the system, and the room temperature could be successfully controlled to 24°C steady state. Room heating in winter was also demonstrated. Since the air was heat exchanged, the overall energy efficiency of the cooling system was low at about 19%. However, the calculation based on the heat flow showed that the efficiency could be enhanced to about 75% by direct heating of the regenerator by the flue gas. [Copyright &y& Elsevier]

One of the most promising applications of poly(L-lactic acid) (PLLA) is food packaging. However, PLLA has a poorer gas barrier property than ordinary food packaging polymers. An improvement of the water-vapor barrier property is therefore required. In this study, low temperature plasma treatment on a stretched PLLA film in the presence of tetramethoxysilane (TMOS) was carried out in order to improve its water-vapor barrier property. The flux of water-vapor permeation through a stretched PLLA film treated with low temperature plasma in the presence of TMOS was decreased to 60% of an untreated stretched PLLA. The effects of plasma treatment parameters on the water-vapor permeability were investigated. [ABSTRACT FROM AUTHOR]

Yakushima Island was used as a model area where material recycling and indigenous energy systems would be realized based on the zero-emission concept in the near future. We evaluated the renewable energy resources to propose a regional energy system on this island. In this paper, the present energy demand and supply structure was quantitatively specified, and the water potential was evaluated. The energy system in Yakushima is unique, with hydroelectric power supplying about 30% of the total energy consumption mainly by commercial and residential sectors. However, petroleum remains the main source of primary energy for transportation, heating, and cooking. The hydroelectric power yielded on the island is sufficient to cover all the energy demands on the island. We found that fossil fuel energy in Yakushima could be substituted with hydroelectric energy without causing an impact on the environment. [Copyright &y& Elsevier]

In bio-oil upgrading, the activity and stability of the catalyst are of great importance for the catalytic hydrodeoxygenation (HDO) process. The vapor-phase HDO of guaiacol was investigated to clarify the activity, stability, and regeneration ability of Al-MCM-41 supported Pd, Co, and Fe catalysts in a fixed-bed reactor. The HDO experiment was conducted at 400 °C and 1 atm, while the regeneration of the catalyst was performed with an air flow at 500 °C for 240 min. TGA and XPS techniques were applied to study the coke deposit and metal oxide bond energy of the catalysts before and after HDO reaction. The Co and Pd–Co simultaneously catalyzed the CArO–CH3, CAr–OH, and multiple C–C hydrogenolyses, while the Fe and Pd–Fe principally catalyzed the CAr–OCH3 hydrogenolysis. The bimetallic Pd–Co and Pd–Fe showed a higher HDO yield and stability than monometallic Co and Fe, since the coke formation was reduced. The Pd–Fe catalyst presented a higher stability and regeneration ability than the Pd–Co catalyst, with consistent activity during three HDO cycles. [ABSTRACT FROM AUTHOR]

• Formation of persistent free radicals (PFRs) by cellulose pyrolysis. • Formation of radical from pyrolysis of intermediates of cellulose pyrolysis. • Stabilization of radical by aromatics formed from cellulose pyrolysis. • Concerted occurrence of radical formation and its stabilization resulted in PFR. • PFR density depends on carbon loss regardless of temperature and its rising mode. Thermal decomposition of cellulose was carried out in a tubular reactor under flowing argon gas at 573, 673 and 773 K. The loss of carbon, hydrogen and oxygen was observed, and enhanced with increase in temperature continuously. The persistent free radicals (PFRs) were not observed in the sample decomposed at the lowest temperature of 573 K, and observed in the samples decomposed at higher temperatures of 673 and 773 K. This incontinuous trend was discussed from viewpoints of radical formation and its stabilization during the thermal decomposition. An empirical correlation between PFR density and residual carbon amount was proposed. [ABSTRACT FROM AUTHOR]

The torrefaction of three representative types of biomass—bamboo, and Douglas fir and its bark—was carried out in a cylindrical-shaped packed bed reactor under nitrogen flow at 573 K of the reactor wall temperature. As the thermal energy for the torrefaction was supplied from the top and the side of the bed, the propagation of the temperature profile of the bed is a crucial factor for discussing and improving the torrefaction reactor performance. Therefore, the temperature and gas flow rate (vector) profiles throughout the bed were calculated by model simulation so as to scrutinize this point. The measured temperature at a certain representative location (z = 30 mm and r = 38 mm) of the bed was well reproduced by the simulation. The volume faction of the bed at temperatures higher than 500 K at 75 min was 0.89, 0.85, and 0.99 for bamboo, and Douglas fir and its bark, respectively. It was found that the effective thermal conductivity is the determining factor for this difference. The heat of the reactions was found to be insignificant. [ABSTRACT FROM AUTHOR]

Bifunctional heterogeneous catalysts have a great potential to overcome the shortcomings of homogeneous and enzymatic catalysts and simplify the biodiesel production processes using low-grade, high-free-fatty-acid feedstock. In this study, we developed ZrO2-based bifunctional heterogeneous catalysts for simultaneous esterification and transesterification of microalgae to biodiesel. To avoid the disadvantage of the low surface area of ZrO2, the catalysts were prepared via a surfactant-assisted sol-gel method, followed by hydrothermal treatments. The response surface methodology central composite design was employed to investigate various factors, like the surfactant/Zr molar ratio, pH, aging time, and temperature on the ZrO2 surface area. The data were statistically analyzed to predict the optimal combination of factors, and further experiments were conducted for verification. Bi2O3 was supported on ZrO2 via the incipient wetness impregnation method. The catalysts were characterized by a variety of techniques, which disclosed that the surfactant-assisted ZrO2 nanoparticles possess higher surface area, better acid–base properties, and well-formed pore structures than bare ZrO2. The highest yield of fatty acid methyl esters (73.21%) was achieved using Bi2O3/ZrO2(CTAB), and the catalytic activity of the developed catalysts was linearly correlated with the total densities of the acidic and basic sites. The mechanism of the simultaneous reactions was also discussed. [ABSTRACT FROM AUTHOR]

Hollow inorganic microparticles were produced continuously from a volcanic glass (shinju-gan or per-lite) using an entrained bed reactor. The microparticles are called expanded perlite. The raw material was a sieved fraction (104 μm in volume average diameter) of crushed perlite, which is from China. The effects of temperature and residence time on expanded perlite yield were investigated. [ABSTRACT FROM AUTHOR]

Primarily produced via transesterification of lipid sources, fatty acid methyl ester (FAME) of biodiesel derived from insect larvae has gained momentum in a great deal of research done over other types of feedstock. From the self-harvesting nature of black soldier fly larvae (BSFL), research had, however, only concentrated on the harvest of BSFL on sixth instar. Through rearing BSFL on coconut endosperm waste (CEW), 100 BSFL were harvested at the fifth and sixth instar, then modification on CEW with mixed-bacteria powder was carried out. It was found that the fifth instar BSFL had 34% lipid content, which was 8% more than the sixth instar. Both instars had similar corrected protein contents around 35–38%. The sixth instar BSFL contained around 19% of chitin, which was about 11% more than the fifth instar. Biodiesel products from both instars showed no differences in terms of FAME content. With modification on CEW, at 0.5 wt% of mixed-bacteria powder concentration, the maximum waste-to-biomass conversion (WBC) and protein conversion (PC) were achieved at 9% and 60%, respectively. Moreover, even with the shorter fermentation time frame of CEW, it did not affect the development of BSFL in terms of its WBC and PC when fed with 14 and 21 days fermented medium. FAME from all groups set, which predominantly constituted about C12:0 at around 60%, followed by C14:0 at around 15%, C16:0, and C18:1 both at 10% on average. Lastly, the FAME yield from BSFL was improved from 25% (sixth instar) to 33% (fifth instar) and showed its highest at 38.5% with modification on raw CEW with 0.5 wt% mixed-bacteria powder and fermented for 21 days. Thus, harvesting BSFL at earlier instar is more beneficial and practical, as it improves the FAME yield from the BSFL biomass. [ABSTRACT FROM AUTHOR]