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The objective of this study is to investigate the effects of slow and fast pyrolysis on the yields and properties of bio-oils using Macadamia nutshell (MNS) as feedstock. A pilot scale auger pyrolysis reactor which had the facilities of conducting both slow and fast pyrolysis was utilized. The pyrolysis processes were carried out at a temperature of 500 ˚C, the heating rate of 5 ˚C/min, a residence time of 60 mins, and a feedstock particle size of 2 mm. The characterization of feedstock and the produced bio-oils was performed by different techniques like elemental analysis, Gas chromatography-mass spectrometry (GC–MS), and physicochemical properties analysis using appropriate ASTM standards. Proximate and ultimate analysis showed promising prospects of MNS as a feedstock for the pyrolysis process. In the case of slow pyrolysis, the bio-oil yield was found to be 39.7%, whereas the bio-oil yield was 49.5% for the fast pyrolysis process. Significant changes in the peak region of GC–MS were observed for bio-oils produced under two different pyrolysis conditions. It was found from the physicochemical properties analysis that calorific value is higher and water content is lower in the bio-oil produced through fast pyrolysis than the bio-oil produced through slow pyrolysis. Comparison with standard biodiesel properties revealed that produced bio-oils were not suitable for use in engines at this stage. Proper upgradation is required to make it suitable for engine application. Based on these results it can be concluded that the produced bio-oils can be used as fuel in other applications such as in boilers and as additives to produce valuable chemicals. [ABSTRACT FROM AUTHOR]

Hydrogen (H2) production has drawn growing interest in energy sector due to its higher potential energy and low carbon emission. As an energy carrier, H2 can be commercially produced from fossil fuels and renewable sources. The significant amount of total H2 production currently is sourced from coal but it releases carbon dioxide (CO2) emission that can cause climate change. Municipal solid waste (MSW) is an alternative source to generate H2 production with lower emission. Generally, MSW can cause harmful effect to the environment through traditional landfill treatment. Therefore, the idea of transforming MSW into H2 through gasification has drawn significant attention in energy sector as it addresses environmental issue while contributing to energy reserve. Besides, H2 generation through gasification has high performance with increased efficiency and low emission. The aim of this paper is to optimize gasification process in aspect of improving H2 yield from MSW. The study has simulated gasification model using different feeds and critically analyzed the effect of operational parameters on energy output. The gasification simulation shows the syngas (H2+CO) production from MSW and coal. The result shows that, although the syngas production from MSW is lower than coal, however it is substantial amount for use in energy sector. It was found that under standard condition, the concentration of H2 from MSW was around 14.18 kg/hr while coal gasification generated at 20.51 kg/hr. Meanwhile, the amount of carbon monoxide (CO) production from MSW was recorded 41.95 kg/hr whereas that from coal was 51.71 kg/hr. It was also found that MSW produces less CO2 than coal which is an advantage of MSW to H2 production through gasification as it is beneficial to environment. The result shows that the toxic gases release from coal was more than that from MSW. For example, CO2 emission from coal feed was approximately 90.28 kg/hr whilst MSW discharge was 72.64 kg/hr. However, the optimised operating condition in gasification process have significant influence on H2 production. It was discovered that with rising gasification temperature from 600 to 1,200 CH2 production increased from 14.18 kg/hr to 25.26 kg/hr. Similarly, steam agent also accelerated H2 production from MSW. Finally, the increment of steam to MSW ratio also increased the concentration of H2. Therefore, H2 can be produced from MSW at lower cost and with reduced emission under optimized operating conditions. [ABSTRACT FROM AUTHOR]

The Beauty Leaf Tree (Callophylum inophyllum) is regarded as an alternative source of energy to produce 2nd generation biodiesel due to its potentiality as well as high oil yield content in the seed kernels. The treating process is indispensable during the biodiesel production process because it can augment the yield as well as quality of the product. Oil extracted from both mechanical screw press and solvent extraction using n-hexane was refined. Five replications each of 25 gm of crude oil for screw press and five replications each of 25 gm of crude oil for n-hexane were selected for refining as well as biodiesel conversion processes. The oil refining processes consists of degumming, neutralization as well as dewaxing. The degumming, neutralization and dewaxing processes were performed to remove all the gums (phosphorous-based compounds), free fatty acids, and waxes from the fresh crude oil before the biodiesel conversion process carried out, respectively. The results indicated that up to 73% and 81% of mass conversion efficiency of the refined oil in the screw press and n-hexane refining processes were obtained, respectively. It was also found that up to 88% and 90% of biodiesel were yielded in terms of mass conversion efficiency in the transesterification process for the screw press and n-hexane techniques, respectively. While the entire processes (refining and transesterification) were considered, the conversion of beauty leaf tree (BLT) refined oil into biodiesel was yielded up to 65% and 73% of mass conversion efficiency for the screw press and nhexane techniques, respectively. Physico-chemical properties of crude and refined oil, and biodiesel were characterized according to the ASTM standards. Overall, BLT has the potential to contribute as an alternative energy source because of high mass conversion efficiency. [ABSTRACT FROM AUTHOR]

Reduction of plastic wastes by means of producing energy can be treated as a good investment in the waste management and recycling sectors. In this article, conversion of plastics into liquid fuel by two thermo-chemical processes, pyrolysis and gasification, are reviewed. The study showed that the catalytic pyrolysis of homogenous waste plastics produces better quality and higher quantity of liquefied fuel than that of non-catalytic pyrolysis process at a lower operating temperature. The syngas produced from gasification process, which occurs at higher temperature than the pyrolysis process, can be converted into diesel by the Fischer-Tropsch (FT) reaction process. Conducive bed material like Olivine in the gasification conversion process can remarkably reduce the production of tar. The waste plastics pyrolysis oil showed brake thermal efficiency (BTE) of about 27.75%, brake specific fuel consumption (BSFC) of 0.292 kg/kWh, unburned hydrocarbon emission (uHC) of 91 ppm and NOx emission of 904 ppm Reduction of plastic wastes by means of producing energy can be treated as a good investment in the waste management and recycling sectors. In this article, conversion of plastics into liquid fuel by two thermo-chemical processes, pyrolysis and gasification, are reviewed. The study showed that the catalytic pyrolysis of homogenous waste plastics produces better quality and higher quantity of liquefied fuel than that of non-catalytic pyrolysis process at a lower operating temperature. The syngas produced from gasification process, which occurs at higher temperature than the pyrolysis process, can be converted into diesel by the Fischer-Tropsch (FT) reaction process. Conducive bed material like Olivine in the gasification conversion process can remarkably reduce the production of tar. The waste plastics pyrolysis oil showed brake thermal efficiency (BTE) of about 27.75%, brake specific fuel consumption (BSFC) of 0.292 kg/kWh, unburned hydrocarbon emission (uHC) of 91 ppm and NOx emission of 904 ppm in comparison with the diesel for BTE of 28%, BSFC of 0.276 kg/kWh, uHC of 57 ppm and NOx of 855 ppm. Dissolution of Polystyrene (PS) into biodiesel also showed the potential of producing alternative transport fuel. It has been found from the literature that at higher engine speed, increased EPS (Expanded Polystyrene) quantity based biodiesel blends reduces CO, CO2, NOx and smoke emission. EPS-biodiesel fuel blend increases the brake thermal efficiency by 7.8%, specific fuel consumption (SFC) by 7.2% and reduces brake power (Pb) by 3.2%. More study using PS and EPS with other thermoplastics is needed to produce liquid fuel by dissolving them into biodiesel and to assess their suitability as a transport fuel. Furthermore, investigation to find out most suitable W-t-E process for effective recycling of the waste plastics as fuel for internal combustion engines is necessary to reduce environmental pollution and generate revenue which will be addressed in this article. [ABSTRACT FROM AUTHOR]