Fuel Communications最新文献

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.

Crop residues are a major component of lignocellulosic biomass waste generated from the agriculture sector. Improper management of these wastes pollutes the environment, contaminates water bodies, and constitutes hazards to human health. The conversion of crop residues to biochar is an ecologically benign and sustainable management strategy for waste management. This review provides a novel insight into the techniques of converting various classes of crop residues such as straws, peels, bagasse, husks, shells, cobs, and stubbles to biochar for biofuel production. The updated information on the description, benefits, and drawbacks of various biochar production techniques including traditional, modern, and novel techniques are also surveyed. The study concluded on the effectiveness of biochar derived from crop residues as sustainable catalysts or support catalysts for biodiesel, biohydrogen, and biomethane production. The deployment of biochar derived from crop residue is cost-effective, eco-friendly, and contributes to environmental sustainability. More multidisciplinary investigations are required to harness the benefits derivable from the application of biochar for biofuel synthesis and confront the challenges associated with the biochar generation process to guarantee the intensification of biofuel production. The use of innovative technologies should be encouraged to guide future research toward ensuring cleaner, cost-effective, and ecological biochar utilization for biofuel production.

This work focuses on the properties of hydrolysis lignin biocarbons with a perspective on utilizing the biocarbons in pyrometallurgical processes. Even if the blast furnace and basic oxygen furnace (BF-BOF) process route was replaced by emerging technologies with lower CO₂ emissions in the future, the need for carbonaceous materials in the iron and steel making industry will still exist. Most of these applications do not require as high standards for the properties of carbonaceous materials as BF but the requirements are still similar to those for BF. The most important properties of carbonaceous materials are the mechanical strength and suitable reactivity. In the case of biocarbon, the apparent density is also considered important. The reactivity and strength properties are investigated with isothermal reactivity tests and compression strength tests for the non-gasified and pre-gasified biocarbon and reference coke samples. The mass loss rate of coke gasification (-0.069%/min) was considerably lower than that of least reactive biocarbon L1200 (-0.18%/min). Regarding the compression strength of the samples, the strength of coke dropped by 56.44% for the samples of pre-gasification level of 50% compared to non-gasified samples while the drop was only 40.68% for the L1200 biocarbon samples. The level of gasification was found to have direct correlation with pore area percentage with R² value 0.92 in case of L1200 and 0.98 in case of coke. Further, the pore area percentage correlated with the compression strength with R² of 0.93 in case of L1200 and 0.98 in case of coke.

In this paper, we develop a series of Artificial Neural Networks (ANN) using different chemical kinetic and thermodynamic input parameters to predict detonation cell sizes. The feedforward neural networks are trained and validated using available experimental data from the Caltech detonation database covering a wide variety of gaseous combustible mixtures at different initial conditions. For each combination of input parameters, a multiple-stage process is followed, which is described in detail, to first determine the best hyperparameters of the ANN (hidden layers, nodes per layer, etc.) and secondly to establish through a fitting process the optimal parameters for each specific network. The performance of the artificial neural networks with different input features is assessed using data from the same source, but that is kept independent and separate from the training and validation process of the ANN. It is found that ANN with three features can provide an accurate estimation of detonation cell size, while increasing the number of features does not improve the accuracy of the ANN. It is also found that the input parameters with the best performance relate indirectly to the stability parameter χ.

SiO₂np derived from rice husk were chemically connected to the surface of modified Calcium Oxide (CaO) in a straightforward manner to produce fatty acid methyl ester (FAME) from waste cooking oil (WCO) with great efficiency. After 3 h at a reaction temperature of 80° C, it was discovered that WCO could produce 97.8% yield of the FAME of the modified CaO, which is much greater than the yield of 83.5% over unmodified CaO under the same reaction circumstances. The results showed that following modification, well-dispersed CaO with relatively tiny particle sizes and large surface areas was produced. Additionally, the changed CaO with very little Ca(OH)₂ is produced during the modification process. The use of leftover modified CaO-nanoparticles as a heterogeneous transesterification catalyst has been identified after fourteen cycles.

Biomass plays an essential role in enhancing global energy security and decreasing carbon emissions as a promising renewable energy option. Comprehensive techno-economic assessments have been carried out to spark industry stakeholders' interest and increase their investment in biomass-based enterprises. To provide a more accurate and reliable feasibility estimate, the evaluation must also take into account a variety of uncertainties in the biomass conversion industry. This review aims to present an overview of the various types of methodologies or techniques used in the techno-economic assessment of the viability of biomass conversion processes, and highlight the uncertainties that need to be taken into account in the evaluation model. A systematic literature review is used where four electronic databases viz., Scopus, Web of Science, Dimensions, and PubMed were used to identify the most recent original research articles in peer-reviewed journals. A total of 346 studies, covering the period 2012–2022 were screened for relevance to the study. Seventy-eight records (n=78) which include only original research articles met the inclusion criteria. The review identified several financial factors and uncertainties that affect the economic performance of fast pyrolysis systems. Furthermore, upgrading the bio-oil to transportation fuels and value-added biochemicals can significantly improve the economic performance of fast pyrolysis plants as opposed to selling raw bio-oil.