Fuel Communications最新文献

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.

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%.