• Energy Research
• 11. Sustainability close
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The biodiesel from lignocellulosic materials has been widely recognized as an alternative fuel to meet energy requirements worldwide, facing fossil fuel depletion, and emerging energy policies. In this work, the biorefinery approach was applied for biodiesel production from jatropha and palm oils in order to make it economically competitive by the utilization of residual biomass as the feedstock for obtaining hydrogen via steam reforming of glycerol and gasification. The linear chains for hydrogen and diesel were simulated using UniSim software and main stream properties were collected from the literature or predicted by correlations. The proposed scheme of biorefinery was analyzed through environmental and techno-economic assessment to identify the feasibility of this process to be implemented. Three different blends of oils (JO10-PO90, JO20-PO80, and JO30-PO70) were considered in the environmental analysis to determine alternatives for reducing potential environmental impacts (PEIs). It was found that the acidification potential highly contributed to the environmental impacts attributed to the use of fossil fuels for heating requirements, and JO30-PO70 blend exhibited the lowest PEI value. The economic indicators were calculated to be 8,455,147.29 $USD and 33.18% for the net present value and internal rate of return, respectively. These results revealed that the proposed combined biomass biorefinery is feasible to be scaled up without causing significant negative impacts on the environment.

<p>Two different commercial photocatalysts, Degussa P25 and Hombikat UV 100, were used to degrade 1,4-dioxane photocatalytically in an annular slurry photoreactor. The optimum photocatalyst loading for Degussa P25 was found to be 1.5 g L-1 while for Hombikat UV 100 was between 3.0-4.0 g L-1. The photoactivity of Degussa P25 is higher than that of Hombikat at lower photocatalyst loadings whereas it is lower at higher photocatalyst loadings. This was found both experimentally and also by mathematical modeling of the radiation within the photoreactor zone. The photoactivity of UV 100 titanium dioxide was found to be twice that of Degussa P25 at optimum loadings. </p>

Waste plastic oil (WPO) derived from pyrolysis of plastic debris and municipal waste is one of the promising alternative fuels because of its similar carbon chain characteristics and physical properties to diesel fuel. WPO also contains naphtha which is gasoline-like and may not be well-suited to a diesel engine. Technically, naphtha should be eliminated from WPO by distillation, and the resulting product is called distilled waste plastic oil (WPOD). This work experimentally investigates the influences of these fuels burned in a diesel engine on combustion characteristics and exhaust gas emissions. Both WPO and WPOD fuels contribute to the larger amount of nitrogen oxides than diesel fuel. Carbon-based emissions increase when the engine operates with these pyrolysis fuels by retarding the ignition onset of their combustion occurrences. Meanwhile, their shorter-carbon-chain links provide a lower smoke index. However, brake thermal efficiency and brake specific fuel consumption are beneficial because of their high calorific value and cetane index.

The impacts of fossil energy on the climate and environment emphasize the need for alternative energy resources. The use of waste wood is one such method to potentially reduce fossil-based energy dependence. However, raw biomass fuel properties are generally poor and unpredictable, thus requiring pretreatment to maximize their energy potentials for an efficient conversion to syngas via pyro-gasification. Two species of pine sawdust (PSD) wastes generated in abundance from large-scale timber industries in Nigeria and South Africa were investigated for improvements in their fuel properties after torrefaction. Samples were torrefied under optimum conditions of 300 °C and 45 min. Different analytical procedures show that the higher heating value (HHV), enhancement factor, energy density, and solid yield of the Nigerian PSD exceeded those of their South African counterpart by 2.38, 5.37, 3.49, and 11.15%, respectively. The HHV of the torrefied fuels increased by 57.29 and 37.9% for the Nigerian and South African PSDs, respectively, when compared to the raw fuels. Also investigated were improvements in their H/C and O/C ratios and thermal degradation at varied heating rates.

The transparent envelope structures in existing buildings have caused so much energy consumption. As one kind of the energy-saving technologies and strategies, the solar spectrum selective absorption film (SSAF) is considered suitable for the retrofit of glazing systems. The energy-saving performance of the SSAF in different types of glazing systems under different climate zones in China was investigated via a field study and simulation experiment. The results indicated that SSAF slowed down the rise of indoor air temperature in the daytime and reduced the total energy entering the room. The effect of the SSAF on the single glazing system was more potent than that on the double glazing system. In the hot summer and cold winter zone, moderate zone, hot summer and warm winter zone, the SSAF could reduce the energy consumption of windows. The highest energy-saving rate reached 35.0% for the single glazing system and 28.3% for the double glazing system. However, the SSAF does not have the energy-saving potential in existing buildings that already have low-E double glazing systems.

Blending dimethyl ether (DME) into liquefied petroleum gas (LPG) has become a common phenomenon. On December 3, 2019, an LPG/DME explosion occurred in Beijing, resulting in 4 deaths and 10 injuries. To deeply investigate the cause and explosion process of the explosion accident, the accident investigation method combining on-site inspection, material evidence analysis, experimental verification, and logical reasoning was used. In addition, the location of the ignition point, the explosive substances, the cause of the gas leakage, the process and the distribution characteristics of the gas leakage, and the ignition process were successively reasoned and analyzed in detail. The results show that the LPG/DME-blended gas can effectively corrode silicone flange gaskets, forming laminar fractures and radial cracks on the gasket. As a result, the tensile strength of the gasket decreased. Under the action of the gas pressure inside the pipeline, the gasket was torn and a leakage hole was formed. The leaked combustible gas formed at least 305 m3 of the explosive gas mixture inside and outside the refrigerated storage. The investigation and research results have important scientific guiding significance for revealing the cause and preventing similar accidents.

Studies have shown that anaerobic digestion (AD) has an effect on the liquid and solid product property of sequential pyrolysis, but its influence on the gaseous products is lacking. In this study, syngas produced by pyrolysis from three raw organic solid wastes and the corresponding digestates, i.e., food waste, vinasse, and cow manure were investigated. AD causes a decrease in the contents of volatile solid, fixed carbon, C, H, and N and an increase in the S content. The weight loss of the wastes mainly occurs at 200-550 °C during the pyrolysis and the loss of the food waste and vinasse is higher than that of cow manure. In the carbon (C)-containing gas, AD leads to a decrease in the CH4 content of the syngas, implying that the heat values of the digestates are lower than that of the raw substrates. After AD, the total amount of nitrogen (N)-containing gas from the vinasse increases by 40.1%, while that from cow manure decreases by 14.1%. On the contrary, the total amount of sulfur (S)-containing groups in the syngas from vinasse drop by 22.0%, while that from cow manure increases by 9.1%. In addition, slight changes in the C-, N-, and S-containing gases are found from food waste. The results indicate that AD has a different effect on the N- and S- containing gaseous groups from different organic solid wastes, and the mechanisms deserve further investigation. The findings supply a theoretical foundation for environmental-friendly application of syngas from the digestates.