Fuel Communications最新文献

A multi-agency effort is underway to decarbonize the aviation industry by 2050 and replace current fossil fuels such as Jet A. Carbon-free hydrogen-based technologies are a long-term opportunity for some markets, but the introduction of new sustainable aviation fuels (SAF) is necessary for a fleet-wide transition. These biofuels are synthesized to meet specific aviation fuel requirements; thus, they may be used in current jet engines without major modifications (i.e., drop-in SAF), accelerating the transition to net-zero carbon emissions by focusing on the life cycle of the biofuel (i.e., circular economy). Given the increased costs associated with the SAF certification process, a deeper understanding of the biofuel behavior at relevant operating conditions, ranging from take-off to high-altitude relight, becomes necessary to define the best candidates. This work investigates the performance of a real-fluid model (RFM), built upon cubic equations of state, in predicting the relevant fuel properties that dictate the atomization, evaporation, and combustion processes. The simpler composition spectrum of SAFs compared to current fuels justifies the development of this modeling approach targeting its application to computational fluid dynamics (CFD) solvers as a more detailed alternative to typical surrogate mixing rules and tabulated properties. The study showcases the capabilities of the RFM using National Jet Fuels Combustion Program's (NJFCP) Category C fuels and offers guidelines toward the development of reliable and robust fluid-dynamics models to support the adoption of SAF in a broad range of conditions, including transcritical regimes. Here, the behavior of the mixtures challenges the validity of ideal fluid models and, therefore, the proposed formulation allows for a realistic fuel characterization at high-pressure and high-temperature conditions, and to explore beyond the currently available experimental datasets.

The present study investigates the applicability of inexpensive natural clay sepiolite as a solid support for preparing sulfonic acid functionalized nanocatalysts producing biodiesel as an alternative fuel. The nanocatalyst is characterized by standard analyses such as XRD, FT-IR, BET, and FE-SEM to evaluate its physical and chemical properties. To avoid soap formation in the transesterification process and to modify the functionality of a mineral-grade sepiolite, sulfonic acid (Sep-SO₃H) has been used to enhance its activity and stability. The resulting heterogeneous catalyst is a nanosized solid acid that can handle edible waste oil as a low-value feedstock with high levels of impurities and acidity in the feedstock. The biodiesel production efficiency is determined by GC-mass spectrometry. Using 2 wt.% of the nanocatalyst resulted in a conversion of 94.7% of the waste cooking oil, demonstrating the high efficiency and promising potential of the materials and method, considering the nature of the feedstock and excellent recycling performance.

Injection of natural/associated gas is widely used as an efficient method of enhanced oil recovery in carbonate oil reservoirs in both miscible and immiscible conditions. Due to reservoir oil compositional changes by injected gas, asphaltenes instability may occur. In spite of the broad reported studies on gas injection process, the effect of miscible gas injection phenomenon on asphaltenes precipitation and deposition at reservoir conditions has not been well attended. The aim of this study is to recognize the effect of miscible and immiscible injection of natural gas on the asphaltenes deposition, permeability alteration and oil recovery. Additionally, the impact of different live and recombined oil samples on asphaltenes instability is investigated. Permeability alteration by the formation of asphaltenes is analyzed through the permeability measurements before and after gas flooding. Permeability reduction is found to be function of miscibility state, injection pressure and type of oil samples. It is observed that experiments conducted with live oil and at lower injection pressures show more permeability reduction. It is assumed an additional oil recovery associated with fluid path diversion caused by asphaltenes deposition in miscible and immiscible conditions. The miscible gas flooding causes the lower asphaltenes deposition and lower recovery enhancement. These effects are due to the fluid path diversion, nevertheless, miscible natural gas injection has high potential of oil recovery. Due to miscible bank development, the composite core along with higher injection pressure respect to minimum miscibility pressure shows higher recovery in comparison to the short core sample.

The modified Iwate kiln size is 3 m in length and 1.7 m in height. Refractory brick, red clay brick, and cement were used to construct the kiln. The modified Iwate kiln is different from the general Iwate kiln in terms of an added part, i.e., a heat distribution pipe installed inside the kiln. The steel pipe plays an important role in heat flow in the kiln. The cylindrical-shaped pipe has slots at the top and the bottom part for heat to pass from the heat source to biomass. The heat distribution inside the kiln was monitored by thermometers at six positions in three different zones of the kiln, i.e., the front part, the middle part, and the back part. The result showed that all three parts provided the same temperatures, both on the top and bottom parts of the kiln. Bamboo and mango wood were used to test the kiln efficiency of charcoal production. Using 1684 kg of bamboo, the output was 292 kg of bamboo charcoal and 909 kg of crude bamboo vinegar; mango wood charcoal production used 2984 kg of mango wood, producing 550 kg of mango wood charcoal and 1212 kg of crude mango wood vinegar. Both types of charcoal have good quality, with a heat value of 31 MJ/kg. The energy conversion efficiency of the modified Iwate kiln was 41–45 %.

Accelerated global human population growth and the corresponding increased urbanisation and industrialisation have resulted in increased manufacturing of goods, and production and loading of domestic and industrial wastewater overwhelming conventional wastewater treatment plants (CWTPs). The net result has been the release of untreated and partially treated domestic wastewater into water systems posing human health hazards and disturbing aquatic habitat integrity. Considering the severe challenges of wastewater treatment not only in Zimbabwe but in Africa and the world in general, it is prudent to assess the microbial fuel cells (MFCs) as an alternative wastewater treatment method for the CWTPs that have failed to operate efficiently. This purposive literature scoping review aimed to: (a) Examine the concept design and operational efficacy of microbial fuel cells (MFCs), (b) Examine the MFC operational system (c) Outline in brief the evolutionary history and assess the existent prototypes and (d) Establish the drivers and barriers for the uptake of microbial fuel cells (MFCs) from a global and local, Zimbabwe, context. Few prototypes have been utilized in real-world systems; with the majority of them being laboratory-scale based. Although MFCs are effective at treating wastewater, scaling them up is still difficult due to their low power generation. Nonetheless, MFCs' simultaneous wastewater treatment and power generation, low carbon footprint, and reduced sludge production are the main drivers behind their adoption. However, capital and maintenance costs and upscaling remain the major challenges in adopting MFC technology. If MFCs are to be used in developing nations like Zimbabwe, further studies should focus on low-cost materials that guarantee maximum power generation and effective wastewater treatment. To ensure effective wastewater treatment, MFCs should be compatible, and integrated with currently utilized sustainable wastewater treatment systems.

In order to achieve the goal of limiting global warming to 1.5 °C, also the growing aviation industry needs to take measures to reduce their greenhouse gas emissions. Various renewably sourced aviation fuels can significantly reduce greenhouse gas emissions and most of them, except for example liquid hydrogen or LNG, can be used in the existing infrastructure without airport or aircraft modifications. As most of these renewably sourced fuel types are not (yet) produced at commercial scale, many technological assessment parameter (e.g. carbon or energy efficiency) are uncertain. Thus, the goal of this study is to compare two different process routes, both being based on biochemical and thermochemical conversion steps. The processes evaluated against conversion efficiency of the available raw feedstock and process energy requirements. The evaluation uses theoretical and biochemical carbon efficiency as well as energy efficiency as indicators. A steady-state flowsheet simulation for two biogenic process paths via biogas and bioethanol as intermediate products is carried out on the basis of literature data. In addition, the optional use of solid residue from the biotechnological process step by combustion for direct heat supply cases are studied. In the ethanol-based route, about 23% of the carbon in the feed can be recovered as kerosene, whereas this is only about 19% in the biogas route. Simultaneously, the ethanol-based route without the combustion of the residue has an energy efficiency of 28%, while the biogas route has an efficiency of 24%.

Hydrothermal carbonization (HTC) has been established as one of the most promising techniques for producing biofuels from high moisture containing organic samples such as, biomass. However, limited progress is observed in terms of the kinetic modeling of this process. Existing kinetic models involve mechanistic and experimental shortcomings due to the nature of the non-isothermal and isothermal subsequent steps involved in the process. To address these limitations, a distributed activation energy model (DAEM) was applied to predict HTC kinetics of lignocellulosic biomass. The DAEM considered the non-isothermal temperature profile of the reactor to account for the considerable devolatilization taking place during the transient step of heating. A micro-kinetic reactor was fabricated to facilitate kinetic experiments to estimate the DAEM parameters- mean activation energy, standard deviation, and pre-exponential factor. These parameters were found to be 96.03 kJ mol⁻¹, 3 kJ mol⁻¹, and 5 × 10⁸ s ^− 1 respectively, based on experiments at final HTC temperatures of 190 °C and 210 °C for lignocellulosic biomass. Furthermore, the parameters were used to accurately predict HTC kinetics at 230 °C using the estimated parameters at 190 °C and 210 °C. The obtained results would be valuable inputs for reactor design and large-scale simulations for HTC of lignocellulosic biomass.

A Response Surface Methodology (RSM) was used to investigate the effect of reaction temperature and biomass to catalyst (b/c) ratio on the catalytic pyrolysis of three wood sawdust samples in a fixed bed reactor using Green zeolite-Y catalyst synthesized from Ficus exasperate (L.) leaf particles. Temperature (400–700 °C), biomass percentage (60–100%), and catalyst (0–40%) were the independent variables with a total of 15 experimental runs, including 3 center runs, were generated via the Box-Behnken experimental design. The results reveal that biomass/ catalyst (b/c) ratio of 80/20% at 550 °C yielded optimum pyrolytic liquid for Melicia excelsa (Me), Diospyros crassiflora (Dc) and Entada Africana (Ea) as 31 wt.%, 31 wt.%, 30 wt.%, respectively while with the attendance of catalysts at 20% increased the yield of pyrolytic liquid for Me (45 wt.%), Dc (42 wt.%), and Ea (43 wt.%). GCMS analysis of Me (80.81 wt.%), Dc (73.96 wt.%), and Ea (70.26 wt.%) pyrolytic oil reveals the dominance of phenols, ethers, alcohols, ketones, alkanes, and acids. Reduction in acidity, decrease in oxygen content, increase in viscosity of the bio-oil were noticed in biomass/catalyst (b/c) ratio of 80/20 at 550 °C. These measurements show enhanced pyrolysis oil characteristics, which is a boost to its bioenergy potential.

Two different configurations of a system including a cogeneration plant based on molten carbonate fuel cell (MCFC) with internal steam reforming (IR-MCFC) and external steam reforming (ER-MCFC) for producing power and hot water are modeled and investigated thermodynamically. Energetic, exergetic and environmental analyses are performed for the proposed systems and compared with each other from different viewpoints. Effects of various parameters, namely after-burner emissions recycling, fuel utilization ratio, operating temperature of stack and current density are investigated on the output potential voltages and any kind of voltage losses, net generated power, CO₂ emission and energy and exergy efficiencies of two proposed cogeneration plants. The main sources of irreversibility are introduced for each system as well. The comparative analysis revealed that energy efficiencies of the IR-MCFC and IR-MCFC based cogeneration systems are about 14.85% and 4.82% larger than those of the ER-MCFC and ER-MCFC-based cogeneration systems, respectively. Also, exergy efficiencies of the IR-MCFC and IR-MCFC based cogeneration systems are about 14.46% and 11.08% more than exergy efficiencies of their external reforming types, respectively. The results indicated that CO₂ emission of ER-MCFC system (0.18 kg/MW) is almost two times of IR-MCFC system (0.36 kg/MW).

Transesterification reaction of Parkia biglobosa oil (0.61% w/w free fatty acid and 191.65 (mgKOH/g) saponification value) with methanol to biodiesel using heterogeneous bi-functional Clay-Na₂CO₃ catalyst was carried out. The bi-functional heterogeneous clay base catalyst was prepared using incipient impregnation method. Following grinding and sieving, the raw clay mineral was soaked in 9 ml Na₂CO₃ overnight. It was subsequently dried at 120 °C for 12 h and finally calcined at 450 °C for 4 h. The properties of the prepared catalyst was then studied using FTIR, SEM, UV Spectrum, EDS and XRD. The optimum conditions for the transesterification reaction include 12:1 molar ratio of methanol to oil, 2 wt% concentrations of catalyst, reaction temperature of 60 °C and 1.5 h of reaction. The maximum yield obtained under conditions was 94.7%. With the exception of the oxidative stability wahich was higher than the recommended standard by American and European Union, all the other properties of the biodiesel were within the limits of American Standard (ASTM D6751), European Standard (EN 14,241) and Ghana Standard Authority. The catalyst could be cheap with superior activity for which reason it could be a potential candidate for producing biodiesel from new non-edible Parkia biglobosa oil. The application of the biodiesel produced from Parkia biglobosa will help improve the lubrication properties of diesel fuel blend which will subsequently help reduce engine wear in diesel engines since biodiesel is a good lubricant.