Fuel Communications最新文献

The addition of hydrogen in ammonia/air mixtures can lead to the onset of intrinsic flame instabilities at conditions of technical relevance. The length and time scales of intrinsic instabilities can be estimated by means of linear stability analysis of planar premixed flames by evaluating the dispersion relation. In this work, we perform such linear stability analysis for hydrogen-enriched ammonia/air flames (50%H2-50%NH3 by volume) using direct numerical simulation with a detailed chemical kinetic mechanism. The impact of pressure and the inclusion of the Soret effect in the governing equations is assessed by comparing the resulting dispersion relation at atmospheric pressure and 10 atm. Our data indicate that both pressure and the Soret effects promote the onset of intrinsic instabilities. Comparisons with available numerical literature data as well as theoretical models are also discussed.

Waste oil treatment and the burning of fossil fuels are causing environmental problems, thus using waste oils as pyrolysis feedstock to produce high-grade biofuels is receiving a lot of attention. Higher hydrogen and volatile matter contents of waste oils make them an optimal raw material for biofuel production. Conversely, attaining satisfactory effects employing traditional disposal methods such as gasification, solvent extraction, transesterification, membrane technology, and hydro-treating is strenuous. Clean and secure pyrolysis technology can help overcome the present dilemma. Biofuels obtained by the traditional waste oil pyrolysis methods can replace fossil fuel as it has been proven to have a high yield and higher heating value (HHV); however, they contain a high acid value. Nevertheless, treating with metal, zeolites, and other bi-functional catalysts helps decrease the acid value. Energy and time can be effectively saved with improved bio-oil yield and quality by co-pyrolysis with plastic waste. A comprehensive assessment of biofuel production via conventional and progressive pyrolysis of waste oils has been investigated. The current evaluation defines the technical and economical routine for bio-oil production from numerous biomass through pyrolysis. Analyzing the bio-oil production cost is one of the crucial components in determining the market affinity of different alternative biofuels. Bio-oil can be made through biomass pyrolysis using an energy integration approach smoothly. The Life cycle assessment (LCA) of waste oil with co-feeds was also discussed in-depth. The conclusions gained using the following study might influence the research on the bio-oil industry targeted at commercializing the product.

This work investigates the performance of a community microgrid (C-$\mu$Grid) in an islanded mode of operation. A control structure has been developed, which focuses on transient stability of the primary controllers (PCs) of individual distributed energy resources (DERs) in the community, and also when the DERs work in tandem to balance load and generation. This approach shows a method for decoupling the state vectors of a highly coupled system, so that the system parameters can be regulated separately with accuracy, speed and stability. This work also demonstrates a technique for analysing and minimizing the impact of communication delays, which may exist between two controllers at different hierarchies. Besides, our analysis shows that power transferred between the multiple buses of a C-$\mu$Grid causes voltage variation that is different from traditional power distribution. Accordingly, a power transfer method has been proposed. These aforementioned control designs have been modeled for a C-$\mu$Grid structure that forms part of a modified IEEE 13 bus system, and simulated in real-time using OPAL-RT. A comparative analysis has been performed between DER voltage references provided by traditional optimal power flow (OPF) and our proposed method of power transfer. The simulation results show stable system operation during normal condition, and post delay recovery, when our developed control and power transfer methods are used. However, certain combinations of voltage references provided by OPF destabilizes the PCs and degrades the quality of power injection into the grid. These results have been utilized to characterize the functional requirements of a C-$\mu$Grid Central/Distributed Controller.

This paper reports an investigation on the long-term storage stability of high percentage and reformulated biodiesel-diesel blends for the success of renewable energy initiatives. This study mainly focuses on the Indonesian context, where the mandated B30 biodiesel faces stability and hygroscopicity challenges. A novel approach incorporated hydrotreated vegetable oil (HVO) to mitigate instability while increasing the biodiesel percentage and was analyzed during storage stability over six months in highland and coastal areas. A comprehensive analysis evaluates physicochemical properties, including water content, kinematic viscosity, total acid number, oxidation stability, and microbial growth. Based on the results, biodiesel-diesel blends (B30, B40, and B30D10) revealed robust stability and quality under highland and coastal conditions. Acid numbers exhibited a slight upward trend during storage but stayed within specified limits, emphasizing limited oxidative changes. Oxidation stability surpassed standard limits for blends, highlighting the blends' resistance to oxidation, even in higher concentrations. Water content increased over time, reflecting biodiesel's hygroscopic nature, but all blends met diesel fuel standards after 6 months. Furthermore, the investigation provided valuable insights into biodiesel-diesel blends' stability, quality, and potential enhancements, contributing to informed decision-making in fuel formulation and quality control.

This study delves into the combustion characteristics of diesel-vegetable oil blends using an industrial fuel burner, shedding light on essential factors that impact the viability of these alternative fuels in industrial applications. Viscosity, a key concern in vegetable oil-based fuels, can be effectively mitigated by blending with diesel. This viscosity reduction enhances fuel atomization, optimizing combustion efficiency and mitigating nozzle blockages. The study also explores the density variation in these blends, indicating potential implications for combustion kinetics and injection dynamics. Furthermore, the research addresses the trade-off between energy content and viscosity reduction as the calorific value decreases with an increasing volume ratio of vegetable oil. Flame behavior, crucial for combustion system design, exhibits an inverse relationship with the volume ratio of vegetable oil, resulting in shorter and less intense flames at higher vegetable oil content. Through comprehensive experiments, the study demonstrates that increased vegetable oil content leads to reduced flame length and stability, primarily attributed to the elevated density and viscosity of vegetable oil. A comparative analysis highlights the similarity in combustion properties between a 40 % vegetable oil and a 60 % diesel blend, which exhibited a kinematic viscosity of approximately 1.58 cP emphasizing the potential of vegetable oil as a viable substitute for diesel in industrial fuel burners.

The significant rise in plastic consumption and waste generation, coupled with the urgent need for sustainable energy solutions, has led to innovative research seeking to convert plastic waste into valuable resources. This review focuses on the application of hydrothermal carbonization as a promising technique for transforming plastic waste into valuable products. It highlights the suitability of hydrothermal carbonization for plastic waste conversion, and presents recent reports showing promising results, prospects, and a range of potential hydrochar applications, including solid recovered fuels, catalysts, direct carbon fuel cells and supercapacitors. This review further presents the challenges in utilizing plastic hydrochar across different applications, which include feedstock variability, contamination, scalability, material properties, and environmental considerations. The need for optimized synthesis methods, stable performance, and long-term sustainability is also emphasized. The critical evaluation of the applications of hydrothermal carbonization can contribute to advancing sustainable waste management and renewable energy production.

In this study, the effects of transition metal-doping on the physicochemical properties and catalytic performance of HZSM-5 catalysts for the conversion of ethanol to hydrocarbons are investigated using experimental data and secondary data from the literature. Hydrothermally synthesized novel ZSM-5 catalysts were modified with different concentrations (0.5 and 10 wt%) of transition metals (Co, Fe, Ni). Characterizations, including X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray spectroscopy, particle size distribution, N₂ adsorption and NH₃ temperature-programmed desorption, revealed the changes in catalyst properties. The introduction of transition metals affected the surface area, particle size and acidity without altering the MFI structures. In particular, a reduction in surface area was observed, ranging from 2.6 to 23 %, corresponding to the different metal loading of 0.5–10 wt% compared to the surface area of the pure catalyst (397.5 m²/g). In addition, metal-doping led to an increase in Lewis acid sites, accompanied by a decrease in strong acid sites. Catalytic evaluation at 350 °C and a space velocity of 12 h⁻¹ showed improved performance in metal-doped ZSM-5 catalysts, which exhibited high selectivity towards fuel-range hydrocarbons, compared to the unmodified catalyst. Catalysts with low metal doping showed optimal catalytic activity, while high metal doping led to increased coke deposition and deactivation of the catalyst due to an increased concentration of strong acids. These results underline the suitability of metal-modified ZSM-5 for hydrocarbon reactions and provide valuable insights for the optimization of catalysts for ethanol conversion to fuel-range hydrocarbons.

Commercial fast pyrolysis technologies use bed materials, normally natural sand mainly consisting of quartz, acting as circulating heat carrier materials. Nowadays, the commercial conversion of biomass into fast pyrolysis bio-oil (FPBO) is still using ash-lean woody residues as a feedstock since the application of more abundant and possibly cheaper ash-rich agricultural biomass is currently at a significantly lower technology readiness level (TRL). To promote FPBO production from ash-rich biomass, the ash-related issues during the operation process need to be further studied. In the present investigation, the characteristics and formation process of layers formed on quartz bed particles, collected from a bench-scale fast pyrolysis unit based on the rotating cone technology, were studied. Two grass residues, representative of typical Si-K-rich agricultural biomass fuels, were used as feedstocks. Quartz bed particles at different sampling times from startup with fresh bed particles were collected. Scanning Electron Microscopy/Energy-Dispersive Spectroscopy (SEM/EDS) was employed to characterize the layer properties. Bed particle layers exhibited an uneven and discontinuous distribution on the quartz surface. This distribution over bed particles, as well as layer thickness, increased with the operational time. The dominating elements contained in layers were Si, K, Ca, and Cl (excluding O), which resembled that of individual bed ash particles found in the bed samples. In addition, the interpretation of the results was supported by thermodynamic equilibrium calculations. The findings suggest that the process of layer formation was governed by the direct adhesion of non-melted bed ash particles during the fast pyrolysis of grass.

Rapid population growth, industrialization, and socioeconomic development have continued to give rise to increased energy consumption. The global energy sector has been overshadowed by the utilization of fossil-based energy sources with their attendant economic, ecological, and human health consequences. Though the share of renewable energy (RE) production and utilization in the global energy mix has increased in the last few decades, the percentage of deployment indicates that the sector is nonetheless grossly underexploited and underutilized. The current intervention examines strategies for achieving increased development and utilization of hydropower, solar power, wind energy, geothermal, nuclear, and ocean power technologies as cost-effective, eco-friendly, and low-emission RE sources. The strengths, weaknesses, opportunities, threats, and strategies for attaining rapid development and utilization of the underutilized RE sources are examined. The study recommends increased funding and investment, enactment, and implementation of appropriate policies, legal, and regulatory frameworks, human capacity and infrastructural development, improved technologies and innovations, and strengthening of security and safety measures to energy security and sustainability. Governments from various jurisdictions should initiate policies, fund research on novel conversion techniques, and engage in international collaborations to hasten the development and utilization of the underutilized RE towards achieving carbon neutrality.

The biodiesel from Castor was, investigated with a water-cooled four-stroke diesel engine of model CT 110 with B₀, B_5, and B₁₀ without and with dimethyl ether (DME) of 2 % and with a fixed load of (80 %) to study the combustion and emission. The biodiesel was made by alkaline transesterification with NaOH as a catalyst. Using established test protocols, the fuels' characteristics, including their viscosity, surface tension, heating value, flash point, and elemental makeup, were measured. Experimental research is used to determine how the pressure and heat release rate affect the performance characteristics of both reference fuel and the blends. The combustion studies are conducted with engine speeds of 1800, 2400, and 3000 rpm and emissions were analyzed with engine speeds starting from 1600 rpm to 3000 rpm with exhaust gas analyzer Gunt, CT159.02 digital analyzer. From the combustion analysis when the blend ratio increases the cylinder pressure (CP) and heat release rate (HRR) also increase due to oxygen molecules in the biodiesel. The addition of DME to biodiesel blends reduces carbon monoxide (CO) emissions relative to neat diesel and biodiesel blends. With the increase of diesel castor biodiesel blends, nitrogen oxide (NO_X) emissions decreased as a result of the reduction in the HRR. The effect of castor diesel biodiesel blend on the NO_X emissions shows, that when the blend ratio increased the NO_X emissions also increased. When DME is added to a higher blend ratio of castor biodiesel, the engine is operated only at higher engine speed. Specifically, for B₁₀ NO_X emission was detected after engine speed of 2500 rpm. When the engine ran with DME for blends of castor biodiesel the engine was not operated at low engine speed. The increase of diesel castor biodiesel blends in the case of DME mixture unburned hydrocarbon (UHC) emissions increased. The finding of this research work was as the biodiesel blend increased the cylinder pressure and heat release rate also increased. So, using sustainable biodiesel-diesel blends made from castor oil with DME additive it is advisable to operate diesel engines for better emission regulation.