Current Issue : January - March Volume : 2021 Issue Number : 1 Articles : 5 Articles
Lignocellulosic biomass is a vital resource for providing clean future energy with a sustainable environment. Besides lignocellulosic\nresidues, nonlignocellulosic residues such as sewage sludge from industrial and municipal wastes are gained much\nattention due to its large quantities and ability to produce cheap and clean energy to potentially replace fossil fuels. These cheap\nand abundantly resources can reduce global warming owing to their less polluting nature. The low-quality biomass and high ash\ncontent of sewage sludge-based thermal conversion processes face several disadvantages towards its commercialization. Therefore,\nit is necessary to utilize these residues in combination with coal for improvement in energy conversion processes. As per author\ninformation, no concrete study is available to discuss the synergy and decomposition mechanism of residues blending. The\nobjective of this study is to present the state-of-the-art review based on the thermal coconversion of biomass/sewage sludge, coal/\nbiomass, and coal/sewage sludge blends through thermogravimetric analysis (TGA) to explore the synergistic effects of the\ncomposition, thermal conversion, and blending for bioenergy production. This paper will also contribute to detailing the\noperating conditions (heating rate, temperature, and residence time) of copyrolysis and cocombustion processes, properties, and\nchemical composition that may affect these processes and will provide a basis to improve the yield of biofuels from biomass/\nsewage sludge, coal/sewage sludge, and coal/biomass blends in thermal coconversion through thermogravimetric technique.\nFurthermore, the influencing factors and the possible decomposition mechanism are elaborated and discussed in detail. This study\nwill provide recent development and future prospects for cothermal conversion of biomass, sewage, coal, and their blends....
The realization and stable operation of Continuous Rotating Detonation (CRD) in the annular combustor fueled by hydrocarbonair\nare still challenging. For further investigation of this issue, a series of ethylene-air CRD tests with the variation of combustor\nwidth is conducted, and the effects of combustor width are well analyzed based on high-frequency pressure and high-speed\nphotograph images. The results show that the combustor width plays a significant role in the realization and sustainability of the\nethylene-air CRD. In this paper, the critical combustor width for the CRD realization and stable single wave are 20mm and\n25 mm, respectively. In wide combustors, the backward-facing step at the combustor forepart makes the main flow slow down,\nand thus, the mixing quality is promoted. Besides, the pilot flame at the recirculation zone contributes to sustaining the CRD\nwave. As the width increases, the propagation mode changes from counter-rotating two-wave mode to single wave mode with\nhigher propagation velocity and stability. The highest propagation velocity reaches 1325.56 m/s in the 40mm wide combustor,\naccounting for 71.51% of the corresponding Chapman-Jouguet velocity. Despite large combustor volume, high combustor\npressure is obtained in detonation combustion mode indicating that a better propulsive performance could be achieved by CRD....
The effects of steam injection on combustion products and thermodynamic properties of diesel fuel, soybean oil-based biodiesel\n(NBD), and waste cooking oil biodiesel (WCOB) are examined in this study by considering the chemical equilibrium. The model\ngives equilibrium mole fractions, specific heat of the exhaust mixtures of 10 combustion products, and adiabatic flame temperatures.\nThe results show that the mole fractions of carbon monoxide (CO) and carbon dioxide (CO2) decrease with the steam\ninjection ratios. Nitric oxide (NO) mole fractions decrease with the steam injections ratios for lean mixtures. The specific heat of\ncombustion products increases with the steam injection ratios. The equilibrium combustion products obtained can be used to\ncalculate the nonequilibrium values of NO in the exhaust gases using some existing correlations of NO kinetics....
In this study, fly ash (FA) and multiwalled carbon nanotubes (MWCNTs) were used to make environmentally friendly\nnanocomposites, which have high fire retardant properties and high mechanical properties. Industrial waste such as fly ash has\nbecome a major concern during the treatment of environmental pollution.MWCNTs were used in this experiment to enhance the\nflame retardant properties and mechanical properties of materials with fly ash additives. MWCNTs content (0.03, 0.04, and 0.05\nwt.%) and fly ash content (30, 40, and 50 wt.%) were studied for three different levels. The flame retardancy of the material is\nsignificantly improved by the addition of fly ash/MWCNTs at different rates, especially at 0.04 wt.%MWCNTs and 40 wt.%fly ash\nwith LOI at 26.8%. Regarding mechanical properties, tensile strength increases as fly ash/MWCNTs increase, up to a critical point.\nOn the other hand, the compressive strength of composite increases continuously as fly ash/MWCNTs increase. Scanning electron\nmicroscopy (SEM) was used to observe the morphology of fly ash and MWCNTs as well as its distribution in the matrix. This will\nhelp analyze the influence of the effectiveness of the combination of fly ash and MWCNTs to the flame retardancy and mechanical\nproperties of fly ash/MWCNTs/epoxy nanocomposites....
The inefficient indoor burning of fuelwood on traditional cookstoves generates pollutants, primarily carbon monoxide and many\nother human health-damaging emissions. It is from this risk that it is necessary to have an immediate shift to alternative cleaner fuel\nsources. Biogas, which is among the biofuels from biomass, is one of the resources that play a considerable part in a more diverse\nand sustainable global energy mix. For domestic purposes in rural areas of Tanzania, biogas provides a better option that can\nsupplement the use of fossil fuels such as wood, charcoal, and kerosene, which is nonrenewable. However, the low efficiency\nexperienced in the locally made biogas burners hinders the large-scale use of biogas among the population in the country. With\nthe locally made burners, the users of biogas for the domestic application face problems including heat loss and high gas\nconsumption which affects the whole cooking process. It is against this backdrop that the current study objectives incline on\ndesigning and improving the efficiency of the locally manufactured burners to achieve the uniform flow of fuel in the mixing\nchamber, which will result to the consistent heat distribution around the cooking pot....
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