Pyrolysis of Canarium schweinfurthii hard-shell: Thermochemical characterisation and pyrolytic kinetics studies.

Canarium schweinfurthii fruit used in food and cosmetics produces waste nuts with a hard shell (hard-shell) and kernel. The hard-shell contained lignin and holocellulose, besides 51.99 wt% carbon, 6.0 wt% hydrogen, 41.68 wt% oxygen, and 70.97 wt% volatile matter. Therefore, this study commenced thermochemical investigations on the hard-shell through extensive intermediate pyrolysis and kinetic studies. During the active stage of thermogravimetric pyrolysis, the hard-shell lost a maximum of 56.45 wt%, and the activation energies obtained by the Kissinger-Akahira-Sunose, Flynn-Wall-Ozawa, and Starink methods were 223, 221 and 217 kJ/mol, respectively. The Flynn-Wall-Ozawa method depicted the degradation process accurately, where the Coat-Redfern method's contraction and diffusion mechanisms governed the pyrolysis reactions at activation energies of 16.62 kJ/mol and 38.83 kJ/mol, respectively. The pyrolysis process produced 25 wt% biochar and 25 wt% bio-oil under optimum conditions. The calorific values of the bio-oils with 6.81-7.11 wt% hydrogen and 68.01-71.12 wt% carbon was 26.32-27.83 MJ/kg, with phenolics and n-hexadecanoic and oleic acids as major compounds. Biochar, by contrast, has a high carbon content of 75.11-79.32 wt% and calorific values of 25.45-28.61 MJ/kg. These properties assert the biochar and bio-oils among viable bioenergy sources.

Physicochemical analysis and intermediate pyrolysis of Bambara Groundnut Shell (BGS), Sweet Sorghum Stalk (SSS), and Shea Nutshell (SNS).

ABSTRACTThe current work focused on the intermediate pyrolysis of Bambara Groundnut Shells (BGS-G1), Sweet Sorghum Stalk (SSS), and Shea Nutshells (SNS). These feedstocks are readily available as wastes or by-products from industrial and agricultural activities. The thermo-gravimetric analysis of the biomass samples exhibited decomposition and devolatilization potentials in the temperature range of 110-650°C. The kinetic modelling resulted in the activation energy of BGS G1 being the lowest as 20.43 kJ/mol and SNS as the highest 24.89 kJ/mol among the three biomass samples. Intermediate pyrolysis was conducted in a vertical tube reactor at a temperature of 600°C, with nitrogen flow at 10 ml/min and heating rate ≥ 33.0℃/min. The yield of pyrolysis bio-oil was 38.0 ± 6.4, 44.2 ± 6, and 39.7 ± 5.2 wt.% for BGS-G1, SSS, and SNS, respectively. The HHV of bio-oil varied as 23.7 ± 1.8, 23.8 ± 1.8, to 26.5 ± 2.0 MJ/kg for BGS-G1 SSS and SNS respectively. The biochar recorded the lowest HHV for BGS-G1 as 18.8 ± 1.2 MJ/kg and the highest for SNS as 26.4 ± 1.8 MJ/kg. The FTIR of bio-oil revealed significant functional groups, and GC-MS (Gas Chromatography and Mass Spectrometry) analysis categorized the compounds in bio-oils as ketones, furans, phenolics, acids, phenols and benzene derivatives. The physicochemical analysis of the feedstocks and the products (bio-oil and biochar) showed their potential for bioenergy and biochemical (green chemicals) production.

Evaluation of potential feedstock for biogas production via anaerobic digestion in Malaysia: kinetic studies and economics analysis.

As the population increases, energy demands continue to rise rapidly. In order to satisfy this increasing energy demand, biogas offers a potential alternative. Biogas is economically viable to be produced through anaerobic digestion (AD) from various biomass feedstocks that are readily available in Malaysia, such as food waste (FW), palm oil mill effluent (POME), garden waste (GW), landfill, sewage sludge (SS) and animal manure. This paper aims to determine the potential feedstocks for biogas production via AD based on their characteristics, methane yield, kinetic studies and economic analysis. POME and FW show the highest methane yield with biogas yields up to 0.50 L/g VS while the lowest is 0.12 L/g VS by landfill leachate. Kinetic study shows that modified Gompertz model fits most of the feedstock with R 2 up to 1 indicating that this model can be used for estimating treatment efficiencies of full-scale reactors and performing scale-up analysis. The economic analysis shows that POME has the shortest payback period (PBP), highest internal rate of return (IRR) and net present value (NPV). However, it has already been well explored, with 93% of biogas plants in Malaysia using POME as feedstock. The FW generation rate in Malaysia is approximately 15,000 tonnes per day, at the same time FW as the second place shows potential to have a PBP of 5.4 years and 13.3% IRR, which is close to the results achieved with POME. This makes FW suitable to be used as the feedstock for biogas production.