Numerical simulation and experimental validation of microwave torrefaction for empty fruit bunches pellet

This study investigates the microwave heating and torrefaction process of empty fruit bunch (EFB) pellets. Finite element based COMSOL Multiphysics software was used to predict the microwave heating behaviour of EFB pellets during the torrefaction process. The simulated temperature data from multimode microwave system at 2.45 GHz frequency was used to compare and validate the experimental results. Quantitative validation of 10 min temperature profiles between 25-300 °C was performed by comparing the simulated and experimental results. RMSE and maximum different temperature profile were 16.42 and 38°C respectively which may cause by the moisture of pellet, exothermic reaction and placement of the thermocouple during microwave torrefaction process. The simulation work has successfully identified the hot spots of EFB pellets during microwave torrefaction. Hot spot happened in the temperature range of 250-450 °C and was observed near the waveguide and centre of the EFB pellets bed. This study provided a framework and required model parameters to predict temperature profile and hot spot location for a specific geometry of microwave cavity

Oil palm waste: An abundant and promising feedstock for microwave pyrolysis conversion into good quality biochar with potential multi-applications

Oil palm waste (OPW), comprising mainly of empty fruit bunch, mesocarp fiber, frond, trunk, and palm kernel shell generated from palm oil industry, was collected, characterized, and then pyrolyzed to evaluate their potential to be converted into biochar with desirable properties for use in multi-applications. The OPW was detected to have considerable amounts of carbon (43–51 wt%) and fixed carbon (30–39 wt%), showing potential to be converted into carbon-rich biochar. Microwave pyrolysis of palm kernel shell as the selected OPW produced a biochar with zero sulphur content and high heating value (23–26 MJ/kg) that is nearly comparable to conventional coal, thus indicating its potential as an eco-friendly solid fuel. The biochar obtained was also showed low moisture (<3 wt%) and ash (3 wt%), and a highly porous structure with high BET surface area (210 m2/g), indicating the presence of many adsorption sites and thus showing desirable characteristics for potential use as pollutant adsorbent in wastewater treatment, or bio-fertilizer to absorb nutrient and promote plant growth. Our results demonstrate that OPW is a biowaste that shows exceptional promise to be transformed into high-grade biochar rather than simply disposed by landfilling or burned as low-grade fuel in boiler

Production of value-added liquid fuel via microwave co-pyrolysis of used frying oil and plastic waste

The production of household wastes such as used frying oil (UFO) and plastic waste (PW) are increasing each year, thus representing potential feedstocks for conversion into an energy source. Microwave co-pyrolysis was investigated for its potential to transform a mixture of UFO and polyolefinic-based plastic waste into fuel product with desirable properties. The co-pyrolysis approach demonstrated positive synergistic effects in providing fast heating rate (up to 50 °C/min) and a lower reaction time (≤25 min), and generated up to 81 wt.% yield of liquid oil and 18 wt.% yield of pyrolysis gases for use as potential fuels. The liquid oil showed promising green properties comprising low oxygen content, free of nitrogen and sulphur and higher energy content (42–46 MJ/kg). The oil product also demonstrated improved stability and desirable fuel properties nearly similar to transport-grade diesel, thus indicating the great potential of microwave co-pyrolysis as an approach for transforming household wastes into value-added liquid fuel

Recent progress in the production and application of biochar and its composite in environmental biodegradation

Over the past few decades, extensive research has been conducted to develop cost-effective and high-quality biochar for environmental biodegradation purposes. Pyrolysis has emerged as a promising method for recovering biochar from biomass and waste materials. This study provides an overview of the current state-of-the-art biochar production technology, including the advancements and biochar applications in organic pollutants remediation, particularly wastewater treatment. Substantial progress has been made in biochar production through advanced thermochemical technologies. Moreover, the review underscores the importance of understanding the kinetics of pollutant degradation using biochar to maximize its synergies for potential environmental biodegradation. Finally, the study identifies the technological gaps and outlines future research advancements in biochar production and its applications for environmental biodegradation

Fungal fermented palm kernel expeller as feed for black soldier fly larvae in producing protein and biodiesel

Being the second-largest country in the production of palm oil, Malaysia has a massive amount of palm kernel expeller (PKE) leftover. For that purpose, black soldier fly larvae (BSFL) are thus employed in this study to valorize the PKE waste. More specifically, this work elucidated the effects of the pre-fermentation of PKE via different amounts of Rhizopus oligosporus to enhance PKE palatability for the feeding of BSFL. The results showed that fermentation successfully enriched the raw PKE and thus contributed to the better growth of BSFL. BSFL grew to be 34% heavier at the optimum inoculum volume of 0.5 mL/10 g dry weight of PKE as compared to the control. Meanwhile, excessive fungal inoculum induced competition between BSFL and R. oligosporus, resulting in a reduction in BSFL weight. Under optimum feeding conditions, BSFL also registered the highest lipid yield (24.7%) and protein yield (44.5%). The biodiesel derived from BSFL lipid had also shown good compliance with the European biodiesel standard EN 14214. The high saturated fatty acid methyl esters (FAMEs) content (C12:0, C14:0, C16:0) in derived biodiesel made it highly oxidatively stable. Lastly, the superior degradation rate of PKE executed by BSFL further underpinned the sustainable conversion process in attaining valuable larval bioproducts

Static Stability Study of a Shallow Vee Hull Airboat for Sarawak Riverine Application

This research aims to evaluate and explore the alternative of water transport varieties. Sarawak with riverine condition has shown a high potential of airboat application and development prospect as transportation is essential to bring people closer. This research acts as a preliminary work that aims to take a fresh look on the Static stability of existing Shallow Vee hull and follow with the PROLINES simulations for another two types of hull designs, which are Flat Bottom and Modified hull. Centre gravity (KG), metacentric height (GM) and metacentre above centre of buoyancy (BM) have shown the major influencing parameters manipulating the static stability of airboat. Besides that, an airboat with Shallow Vee hull was made for the stability performance testing in UNIMAS’s pool, and it has given an acceptable range of testing results. Rpm of propeller, fuel consumption and wind speed have been measured before hand. Subsequently airboat is operated to measure the average speed and observed the overall stability during the turning. Naval architecture software, PROLINES is used for simulation work of different displacement and type of hulls. Simulation results have evaluated the airboat hydrostatics and statics stability performance. As a result, Flat Bottom and Modified hull gives merits of static stability compared to Shallow Vee hull

Formation of Stainless Steel Nanoballs via Submerged Glow-discharge Plasma and their Microstructural Analysis with Evaluation of Photocatalytic Activity

Stainless steel has shown potential as a catalytic material in bulk form. However, it only becomes active in an aqueous acidic environment and elevated temperatures. This study aims to produce stainless steel nanoparticles that have high photocatalytic activity in a neutral medium and at room temperature and to elucidate the photocatalytic activity mechanism of the nanoparticles. Spherical, photocatalytic nanoparticles called “nanoballs” were synthesized by the submerged glow-discharge method. Stainless steel SUS316L grade wire was used as the cathode, platinum mesh was used as the anode while the electrolyte was potassium carbonate. The nanoballs were obtained after centrifuging and washing with water. The physical characteristics of the photocatalytic nanoballs were analysed by scanning electron microscopy, high-resolution transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffraction. The nanoballs were mixed with methylene blue and irradiated with ultraviolet light for the evaluation of photocatalytic reaction. The photodecomposition samples were determined using UV-vis spectrometry. The by-products of the photodecomposition were evaluated using mass spectrometry. The results show that stainless steel nanoballs have photocatalytic activity when irridiated with ultraviolet light at room temperature. Submerged glow-discharge plasma method can synthesize nanoparticles rapidly using only metal wires as the electrode

Microwave pyrolysis using self-generated pyrolysis gas as activating agent: An innovative single-step approach to convert waste palm shell into activated carbon

Waste palm shell (WPS) is a biomass residue largely available from palm oil industries. An innovative microwave pyrolysis method was developed to produce biochar from WPS while the pyrolysis gas generated as another product is simultaneously used as activating agent to transform the biochar into waste palm shell activated carbon (WPSAC), thus allowing carbonization and activation to be performed simultaneously in a single-step approach. The pyrolysis method was investigated over a range of process temperature and feedstock amount with emphasis on the yield and composition of the WPSAC obtained. The WPSAC was tested as dye adsorbent in removing methylene blue. This pyrolysis approach provided a fast heating rate (37.5°/min) and short process time (20 min) in transforming WPS into WPSAC, recording a product yield of 40 wt%. The WPSAC was detected with high BET surface area (≥ 1200 m2/g), low ash content (< 5 wt%), and high pore volume (≥ 0.54 cm3/g), thus recording high adsorption efficiency of 440 mg of dye/g. The desirable process features (fast heating rate, short process time) and the recovery of WPSAC suggest the exceptional promise of the single-step microwave pyrolysis approach to produce high-grade WPSAC from WPS