Liquid Fuels Research Articles

Enhancing the selective catalytic oxidation of lignocellulosic biomass to formic acid using hydrogen peroxide and a reusable MgAl hydrotalcite-derived as a catalyst in a green solvent

Biofuels or liquid fuels derived from natural matter, are one of the most intriguing yet divisive alternatives for petroleum-based fuels. The most common approach to produce biofuels is to transform plant sugars and other carbohydrates into oxygen-deficient chemicals. A growing relevance has been devoted in the direct synthesis of platform molecules from biomass resources, using one-pot or cascade techniques via adequate catalytic system tuning and improvement of the reaction conditions which have merged as a beneficial strategy from an economic and ecological standpoint. In a similar vein, the major objective of this contribution was to investigate and enhance the conditions for a selective oxidation of lignocellulosic biomass-derived cellulose to yield formic acid (FA), the latter is one of the most coveted liquid hydrogen carriers and among the key compounds used in the pharmaceutical, cosmetic, and leather industries. Both oxidizing aqueous hydrogen peroxide and calcined heterogeneous hydrotalcite catalyst have been employed at an atmospheric pressure for this purpose. The effect of reaction time, temperature, amount of catalyst and oxidant on the product's yield and selectivity have been investigated. The oxidation of a plant-derived cellulosic fiber at 70 °C using an H2O2 excess (7 mmol) provided an impressive result with a high yield and TON of 61.0 %, 12.30 respectively, the latter was confirmed to be relatively close to the one from the oxidation of pure cellulose. Furthermore, the reusability of the catalyst has also been studied which was demonstrated to result in the same yields for one reuse and 3 recycles.

The Emissions of a Compression-Ignition Engine Fuelled by a Mixture of Crude Oil and Biodiesel from the Lipids Accumulated in the Waste Glycerol-Fed Culture of Schizochytrium sp.

Microalgae are considered to be a promising and prospective source of lipids for the production of biocomponents for conventional liquid fuels. The available sources contain a lot of information about the cultivation of biomass and the amounts and composition of the resulting bio-oils. However, there is a lack of reliable and verified data on the impact of fuel blends based on microalgae biodiesel on the quality of the emitted exhaust gas. Therefore, the main objective of the study was to present the emission characteristics of a compression-ignition engine fuelled with a blend of diesel fuel and biodiesel produced from the lipids accumulated in the biomass of a heterotrophic culture of Schizochytrium sp. The final concentrations of microalgal biomass and lipids in the culture were 140.7 ± 13.9 g/L and 58.2 ± 1.1 g/L, respectively. The composition of fatty acids in the lipid fraction was dominated by decosahexaenoic acid (43.8 ± 2.8%) and palmitic acid (40.4 ± 2.8%). All parameters of the bio-oil met the requirements of the EN 14214 standard. It was found that the use of bio-components allowed lower concentrations of hydrocarbons in the exhaust gas, ranging between 33 ± 2 ppm and 38 ± 7 ppm, depending on the load level of the engine. For smoke opacity, lower emissions were found in the range of 50–100% engine load levels, where the observed content was between 23 ± 4% and 53 ± 8%.

A Technical-Economic Assessment of Producing Hydrogen and Biofuels via Gasification of Biomass in Solar Hybridised Dual Fluidised Bed

In this work, the techno-economic performances of three conversion pathways using an upstream solar hybridised dual fluidised bed (SDFB) for biomass gasification were assessed. The annual solar share % over the solar multiple range of 1.4-3.4 varies between 7-17%, with the CO2 emissions avoided relative to the non-solar case varying between 7%-23%, using representative solar viability location in Australia. The projected break-even price varies between 5.5-6.1 AUD/kg (3.8-4.25 USD/kg) for hydrogen, 1.1-1.2 AUD/kg (0.75-0.85 USD/kg) for methanol, and 1.5-1.7 AUD/L (1.1-1.2 USD/L) for liquid fuels over the analysed oversize level of 1.4 to 3.4 at thermal storage capacity designs with less than 1% solar dumping rate for base case scenario. Overall, the derived break-even price from the SDFB gasifier configuration is higher than that of the non-solar gasifier case, yet this is dependent on the cost of supplement heat supply and carbon credit

Pore-Structure Engineering of Hierarchical β Zeolites for the Enhanced Hydrocracking of Waste Plastics to Liquid Fuels

Pore-Structure Engineering of Hierarchical β Zeolites for the Enhanced Hydrocracking of Waste Plastics to Liquid Fuels

Desulfurization of pyrolytic oils from waste tire pyrolysis in a fluidized bed reactor with boron nitride adsorbents

The study focused on producing hexagonal boron nitride (hBN) as an adsorbent which provides high efficiency in desulfurization processes. The synthesized hBN is used for sulfur removal from liquid fuel derived from end-of-life tires (ELTs). Characterization of hBN was performed using FTIR, XRD, TGA, and SEM-EDS analyses. Liquid fuel was produced in a fluidized bed reactor at 550 °C under a nitrogen gas flow. Post-desulfurization, the fuel's density, water content, and calorific value increased, while sulfur content and flash point decreased, with sulfur content showing a significant reduction of 79.23 %. The desulfurized fuel (PS-A) exhibited better combustion characteristics and closely resembled diesel fuel performance, though it slightly reduced engine effective efficiency by 1.06 % compared to diesel. Both PS-A and pre-desulfurized fuel (PS-B) significantly reduced soot emissions by 23.28 % and 20.81 %, respectively, compared to diesel. Additionally, CO emissions were lower for PS-A and PS-B, with reductions of 4.35 % and 2.00 %, respectively. However, CO2 emissions increased by 1.60 % for PS-A and 0.86 % for PS-B, attributed to higher fuel consumption. Overall, hBN effectively reduced sulfur content and improved several fuel properties of pyrolytic liquids. The study highlights the environmental and economic benefits of enhancing ELT-derived liquid fuels and suggests potential applications in real systems, serving as a foundation for new technologies and projects.

Green ammonia adoption in shipping: Opportunities and challenges across the fuel supply chain

The IMO’s 2023 revised targets increase pressure on shipping and trading organisations to urgently cut energy consumption and transition away from fossil fuels. Although there are several alternative fuel options for shipping, ammonia is a prominent contender. Green ammonia is produced from renewable hydrogen with no direct CO2 emissions when combusted, making it an important option to interrogate. This research uses a mixed methods approach, including analysing shipping stakeholders’ perspectives, to consider the full range of factors relating to its deployment and use. Challenges to its adoption include low fleet renewal as a result of uncertainties around being first movers, managing NOx and N2O emissions if used in a combustion engine and lack of economic incentives. Nevertheless, green ammonia's storage advantages over hydrogen, established experience of ammonia handling for the fertiliser industry and its direct emission free application in fuel cells, underpin interest in its development. The study emphasizes though that the on-ground realities of transitioning away from fossil fuels require significant developments across the entire fuel supply chain. This extends beyond considerations around ammonia’s technological viability and encompass changes needed to onboard and portside infrastructure, incentives to accelerate retrofit and fleet renewal, and recognition of risks posed by first-movers in the sector. Furthermore, with short timeliness associated with Paris targets, and anticipated rising costs of new fuel infrastructure, there is an imperative to implement mitigation policy that focuses on urgently reducing reliance on liquid fuels, while alternative fuel deployment is established at scale.

Health benefits of US light-duty vehicle electrification: Roles of fleet dynamics, clean electricity, and policy timing

We present a dynamic perspective to quantify the air quality-related health impacts of the electrification of light-duty vehicles in the United States between 2022 and 2050. Using a fleet turnover model and future electricity generation mix scenarios, we compare ambitious vehicle electrification to fleet renewal relying on newer internal combustion engine vehicles, without electric vehicles. The model includes vehicle-level pollutant emission factors and a reduced complexity air quality and valuation model and covers direct (tailpipe, brake wear, and tire wear) and indirect (production of electricity and liquid fuels) emissions of NOx, SO2, PM2.5, NH3, and VOCs, with a breakdown at the county level to identify geographical disparities in the distribution of health impacts. Short-term health benefits are mostly generated by reductions in NOx emissions from newer gasoline vehicles, while fleet electrification generates further benefits in the long term. The electricity mix plays a crucial role in the success of electrification policies. With continued grid decarbonization, electrification would reduce harmful air quality-related health impacts cumulatively by 84 to 188 billion USD over the study period, compared with fleet renewal without electric vehicles. In contrast, artificially freezing the 2022 grid would make electrification responsible for 32 to 71 billion USD additional health disbenefits compared with fleet renewal. Finally, we show that while fleet electrification achieves most of its benefits over fleet renewal in the long term, delaying the implementation of such policies would sacrifice meaningful cumulative benefits.

A concise review towards a novel target specific multi-source unsupervised transfer learning technique for GDP estimation using CO2 emission data

Though economic growths of most of the nations have seen exponential rise due to industrialization, it has also caused proportional increase in their carbon emissions. This paper exploits this proportionate relationship of carbon emission with GDP to predict the per-capita GDP of those nations whose GDP values are missing in the world bank database. The reason behind the same was, those countries were either war-torn or politically isolated/unstable. To achieve the objective of predicting the missing GDP values of those countries from their carbon emissions, this paper exploits the non-linear relationship among the carbon emissions from solid fuels, liquid fuels, and gaseous fuels. It is so because even the differential utilization of these fuels impact economy differently. Use of traditional solid fuel for cooking points toward energy poverty, and access to clean cooking gas indicates higher living standard. However, the available data from the war-torn or isolated countries are very little, and hence insufficient for building a robust predictive machine learning model. So, this paper employs multi-source unsupervised transfer learning to precisely estimate the missing per-capita GDP of those nations. It suitably enlarges the training domains for the prediction models to be more robust. We empirically evaluate the proposed methodology for different regression techniques to estimate the missing GDP values of eleven different nations belonging to diverse strata of economies viz. developed economies, developing, and/or least developing economies. Proposed methodology profoundly improves the prediction preciseness of these regression techniques in estimating the missing per-capita GDP of the considered nations.

Desulfurization of simulated and commercial liquid fuel on nano-ZnO fabricated walnut shells.

The current investigation involved the development of activated carbon, juglans regia activated carbon (JRACs), from walnut shells, scientifically known as Juglans regia. The ZnO nanorods were loaded on the activated carbon and referred to as ZnO@JRACs. Desulfurization efficiency was assessed through batch adsorption and compared to commercial activated carbon known as DARCO. The materials were characterized using PXRD (powder X-ray diffraction), FTIR (Fourier-transform infrared spectroscopy), ICP-AES (inductively coupled plasma atomic emission spectroscopy), BET (Brunauer-Emmett-Teller) surface area analysis, TEM (transmission electron microscopy) imaging, and TGA (thermal gravimetric analysis). The findings indicated that the materials have oxygen functionalities, a porous morphology, and a substantial specific surface area (BET) of 1269.92 m2/g for ZnO@JRACs. Zn atom concentration in the ZnO@JRACs surface was determined to be 1.16 atomic percent using ICP-AES. Desulfurization experiments were conducted on three liquid fuels, namely a single component model fuel, MSF (multicomponent simulated fuel), and commercial fuel (kerosene), under optimized conditions (8g/L adsorbent dosage in 10mL of fuel, 15min of contact time at room temperature). The conditions effectively removed ~ 98.9% of dibenzothiophene (DBT) from the single component model fuel. The observed order for adsorption capacity is as follows: ZnO@JRACs (63.6mgg-1) > JRACs (46.3mgg-1) > DARCO (26.1mgg-1). The analysis of multicomponent simulated fuel (MSF) using gas chromatography-flame photometric detector (GC-FPD) revealed significant removal percentages for different types of thiophenic sulfur. Specifically, the removal percentages were ~ 46.2%, 97.6%, and 99.4% for benzothiophene, dibenzothiophene, and 4, 6-dimethyldibenzothiophene, respectively. Kinetic studies have shown that the adsorption process is governed by a pseudo second-order reaction. Additional thermodynamic studies were conducted to further investigate the mechanism of adsorption. The spent synthesized composite ZnO@JRACs were thermally regenerated and can be reused for up to four cycles.

A numerical framework for modeling evaporation and combustion of isolated, spherically-symmetric, multi-component fuel droplets

This paper presents a comprehensive numerical framework for simulating the evaporation and combustion of isolated, spherically-symmetric, multi-component fuel droplets. The framework incorporates a detailed description of chemical reactions in the gaseous phase and is capable of modeling pure evaporation, autoignition, and hot-wire ignition scenarios.The transport equations for mass, species, and energy are solved in both the liquid (droplet) and gaseous (surrounding atmosphere) phases. Diffusion in the liquid phase is described using the Stefan–Maxwell theory, while in the gaseous phase, both molecular and thermal diffusion are considered. The model also includes the thermophoretic effect for carbonaceous particles and accounts for gas radiation through various models, ranging from optically-thin approximations to more complex methods like the P1 and discrete ordinate methods. Non-gray radiative effects are handled using the Weighted-Sum-of-Gray-Gases Model (WSGGM). Liquid/gas interface conditions are evaluated by imposing flux continuity of mass and energy, along with thermodynamic equilibrium for species. Deviations from ideal thermodynamic behavior in the liquid droplet are managed by incorporating a suitable activity coefficient or by using a proper cubic equation of state. Additionally, the presence of supporting fibers is modeled using a simplified one-dimensional approach. The transport equations are solved using the method of lines, with spatial discretization performed via the finite difference method on a body-fitted grid. The resulting system of Differential–Algebraic Equations (DAEs) is then solved using a fully-coupled approach.Thanks to its generality in terms of kinetic and thermodynamic descriptions and the reduced computational time, the proposed framework offers significant potential for advancing our understanding of the complex combustion processes of multi-component liquid fuels and for enhancing the planning and execution of experiments involving isolated fuel droplets.

Highly Efficient and Selective Hydrodeoxygenation of Guaiacol Using Ni-Supported Honeycomb-Structured Biochar and Phosphomolybdic Acid.

The sustainable development of energy has always been a concern. Upgrading biomass catalysis into hydrocarbon liquid fuels is one of the effective methods. In order to upgrade biomass derivative guaiacol by Hydrodeoxygenation (HDO) catalysis, this article report a three-dimensional honeycomb structure biochar loaded with Ni nanoparticles and phosphomolybdic acid demonstrating excellent catalytic performance in a short period of time. This is due to the porous structure of biochar, which allows Ni metal nanoparticles to be highly uniformly dispersed on the support, which enhances the catalytic hydrogenation of guaiacol in terms of both rate and efficiency. Furthermore, it was observed that the added phosphomolybdic acid dissolved within the temperature range of 78-90°C, functioning as a homogeneous catalyst in the process. This proves advantageous, as the phosphomolybdic acid becomes accessible at any location within the porous Ni/C catalyst. The detailed characterization data revealed that the carbon support prepared in this study has a high specific surface area of up to 1375.61 m2/g. Additionally, the phosphomolybdic acid exhibited rich acidity, with Brønsted and Lewis acid contents of 2.55 μmol/g and 21.45 μmol/g, respectively. Reaction data demonstrated that at 240°C for 180 minutes, 100% conversion and 97.9% cyclohexane selectivity were achieved.

CH4 and CO2 Reductions from Methanol Production Using Municipal Solid Waste Gasification with Hydrogen Enhancement

This study evaluates the greenhouse gas (GHG) impacts of converting municipal solid waste (MSW) into methanol, focusing on both landfill methane (CH4) emission avoidance and the provision of cleaner liquid fuels with lower carbon intensity. We conduct a life cycle assessment (LCA) to assess potential GHG reductions from MSW gasification to methanol, enhanced with hydrogen produced via natural gas pyrolysis or water electrolysis. Hydrogen enhancement effectively doubles the methanol yield from a given amount of MSW. Special attention is given to hydrogen production through natural gas pyrolysis due to its potential for lower-cost hydrogen and reduced reliance on renewable electricity compared to electrolytic hydrogen. Our analysis uses a case study of methanol production from an oxygen-fired entrained flow gasifier fed with refuse-derived fuel (RDF) simulated in Aspen HYSYS. The LCA incorporates the significant impact of landfill methane avoidance, particularly when considering the 20-year global warming potential (GWP). Based on the LCA, the process has illustrative net GHG emissions of 183 and 709 kgCO2e/t MeOH using renewable electricity for electrolytic hydrogen and pyrolytic hydrogen, respectively, for the 100-year GWP. The net GHG emissions using 20-year GWP are −1222 and −434 kgCO2e/t MeOH, respectively. Additionally, we analyze the sensitivity of net GHG emissions to varying levels of fugitive methane emissions.

Asymmetrically Coordinated Cu Dual-Atom-Sites Enables Selective CO2 Electroreduction to Ethanol.

Electrochemical reduction of CO2 (CO2RR) to value-added liquid fuels is a highly attractive solution for carbon-neutral recycling, especially for C2+ products. However, the selectivity control to preferable products is a great challenge due to the complex multi-electron proton transfer process. In this work, a series of Cu atomic dispersed catalysts are synthesized by regulating the coordination structures to optimize the CO2RR selectivity. Cu2-SNC catalyst with a uniquely asymmetrical coordinated CuN2-CuNS site shows high ethanol selective with the FE of 62.6% at -0.8V versus RHE and 60.2% at 0.9V versus RHE in H-Cell and Flow-Cell test, respectively. Besides, the nest-like structure of Cu2-SNC is beneficial to the mass transfer process and the selection of catalytic products. In situ experiments and theory calculations reveal the reaction mechanisms of such high selectivity of ethanol. The S atoms weaken the bonding ability of the adjacent Cu to the carbon atom, which accelerates the selection from *CHCOH to generate *CHCHOH, resulting in the high selectivity of ethanol. This work indicates a promising strategy in the rational design of asymmetrically coordinated single, dual, or tri-atom catalysts and provides a candidate material for CO2RR to produce ethanol.

Thermal pyrolysis behavior and mechanisms of kraft lignin using methane, H2, and H2O as reactive medium: A ReaxFF molecular dynamics simulation

Biomass has become an alternative to fossil fuels due to its capacity to provide carbon-neutral energy. However, the conversion of kraft lignin into high-value chemicals remains challenging. Hydrotreatment, utilizing CH4, H2, or H2O, enables the production of high-quality liquid hydrocarbon fuels while enhancing hydrogen utilization. Reactive molecular dynamics was employed to investigate the influence of CH4, H2, and H2O as reactive medium of kraft lignin at the atomic scale. The three reactive mediums increased the maximum heavy tar yield by 8.34%, 8.07%, and 8.53% respectively, and increased the hydrogen content of pyrolysis products. Steam conditions promote the decomposition of ether bonds, while H2 and CH4 exhibit stronger inhibitory on the decomposition of carbon hexagonal rings. A crucial role of pentagonal carbon rings as intermediates in the lignin cracking process was found. These findings provide valuable insights for optimizing the pyrolysis conditions of kraft lignin to achieve the desired product yields.

Combustion of liquid hydrocarbon fuels sprayed into gas generation chamber with superheated steam as low emission technology for energy production

Experimental and numerical studies were conducted to scientifically validate the Steam Injection Method with Gas Generation chamber (SIMGG) as a low-emission combustion technology for energy production in low and medium power boilers using different types of fuels. For the first time, a fully functional prototype of a burner implementing SIMGG was tested under the conditions of a standard low-power boiler installation, and combustion characteristics of fuels with various physical properties (diesel fuel and a mixture of used automotive oils) were obtained under different operating parameters. The results of the studies show that using SIMGG reduces carbon monoxide (CO) and nitrogen oxides (NOx) emissions by up to half or more under closed-combustion conditions for various fuels. The lowest total emissions of CO and NOx are achieved at an air excess coefficient of 1.2 and a steam-to-fuel ratio of greater than 0.66.

Aquathermolysis of polyolefin plastic wastes over a MOF-derived TiO2 anatase catalyst: Enhancing C–N bond cleavage and coke suppression

Plastics are ubiquitous in modern society owing to their cost-effectiveness, low weight, and durability. However, the disposal and recycling of plastic waste remain significant challenges. Aquathermolysis has emerged as a promising strategy for converting contaminant-rich polyolefin plastic waste into value-added liquid fuels. This study investigates the plastic-waste aquathermolysis potential of a TiO2 catalyst derived from the sacrificial precursor Ti-containing MIL-125 via a MOF-mediated synthesis pathway combined with calcination. The TiO2 catalyst retained its mesoporous properties and predominantly anatase phase on calcination at 450 ℃. The aquathermolysis catalysis and stability of the newly synthesized catalyst for plastic-waste conversion were evaluated and compared with those of other catalytic systems. Additionally, the role of water in the N removal efficiency and coke suppression properties of the catalyst were analyzed. Water significantly improved the removal of N and S impurities, with a N reduction of 80–95% at the optimal water content (20–40 wt%). The robustness of the as-synthesized catalyst was confirmed by deconvoluted X-ray photoelectron spectroscopy patterns, which indicated the persistence of the TiO2 phase, even after prolonged catalysis in aqueous environments, and transmission electron microscopy results, which showed that the anatase phase remained well-dispersed under aquathermolysis conditions with a significant reduction in the C/Ti ratio and a corresponding increment in the N/C ratio. The results of this study could guide future research on the development of catalysts, similar to the MIL-125-derived TiO2 catalyst investigated here, with high potential for efficient plastic-waste conversion and impurity removal in aqueous environments.

An efficient carbon-neutral power and methanol polygeneration system based on biomass decarbonization and CO2 hydrogenation: Thermodynamic and economic analysis

This study presents a novel approach to enhance methanol synthesis (MS) efficiency through integration with an MEA-based decarbonized biomass direct-fired power plant (BFPP-CCS). The integration optimizes the utilization of chemical energy from feedstocks by combining exothermic MS reactions with diverse thermal energies, which effectively captures chemical energy through synergistic utilization from MS and various thermal inputs. Gradual methanol conversion maximizes both its chemical and fuel properties. Through such integration, the enhancement of waste heat and purge gas utilization in MS and BFPP carbon capture processes results in a 3.42 MW improvement in power generation and a 26.0 % reduction in associated energy penalties from CCS. Analysis of a 150 kton/yr MS facility and a 35 MW BFPP-CCS demonstrates 2.87 % increase in overall efficiency and reduction in CCS heat consumption by 1.03 GJ/tCO2. Moreover, this integrated approach yields a 33.1 M$ NPV increase and 3.4 years DPP decrease, achieving carbon-neutral power and liquid fuels production. Sensitivity analysis indicates the polygeneration system performs optimally around 250 °C and 60 bar, with a preference for 0.90 MS recycle ratio. Additionally, factors such as carbon recovery rate, electrolysis efficiency, and fixed carbon content in biomass are quantitatively revealed as crucial for maximizing carbon mitigation potential.

Three-part superposition quasi-static stress model for PTFE across a broad low-temperature range based on ZWT and higher-order stress corrections

The widespread application of cryogenic liquid fuels in aerospace necessitates an accurate description of the mechanical properties of sealing materials such as Polytetrafluoroethylene (PTFE) at low temperatures. This study aims to develop a stress prediction model to describe the tensile stress response of PTFE across a broad low-temperature range. Quasi-static tensile tests on PTFE samples were conducted to obtain the uniaxial tensile properties of PTFE in the low-temperature range. Data fitting revealed significant errors and a loss of physical significance in the classical Zhu–Wang–Tang (ZWT) constitutive model and its modified versions when describing PTFE's mechanical response at low temperatures or large strains. Based on these theoretical models, a three-part superposition (TPS) model, incorporating asymptotic growth, linear growth, and exponential growth terms, is proposed. The TPS model demonstrates excellent predictive accuracy for PTFE's mechanical response from 77 K to 293 K, and from initial strain to fracture. Additionally, the physical connections and interpretations between the three parts of the TPS model and the macroscopic mechanical behavior and microscopic crystalline characteristics of semi-crystalline polymers are analyzed, providing a unified description and a comprehensive understanding of PTFE's mechanical behavior over this temperature range.

A molecular dynamics study on the supercritical evaporation of liquid ammonia under forced convection conditions

Although the behavior of the supercritical transition during the evaporation of liquid fuels in engine combustion chambers has been studied by many researchers, the effects of convection on the phase transition of liquid fuel in supercritical environments have been little studied. Previous studies mainly focused on hydrocarbon fuels for supercritical evaporation, with fewer on the zero-carbon liquid ammonia fuel. Aiming at the above deficiencies, this study used molecular dynamics simulations (MD) to explore the phase transition of liquid ammonia in a nitrogen supercritical environment under forced convection conditions. The Peng-Robinson equation of state (PR-EoS) was used to calculate the vapor–liquid equilibrium of the ammonia–nitrogen system to determine the supercritical transition time of liquid ammonia under forced convection conditions. The effects of forced convection on the heat and mass transfer process and the evolution of the liquid-phase region and the vapor–liquid interface region were analyzed. It was found that forced convection can promote the mass and heat transfer process and accelerate the phase transition of liquid ammonia to some extent. Forced convection may have a greater effect on the single-phase diffusive mixing process compared to the two-phase evaporation process. The increase in the interfacial thickness under forced convection conditions is mainly attributed to the temperature increase promoted by convection. The interfacial temperature dominates the development of its thickness and the thickness is approximately linear with temperature during the diffusive mixing stage. The shear effect induced by convection has an inhibitory effect on the diffusion of ammonia molecules within the interface region along the vertical convection direction. The cases in this study indicate that forced convection may promote the supercritical transition of liquid ammonia. In addition, a dimensionless number κ was proposed to explore the possibility of scaling up the MD results to the engineering scale.

Evaluation of waste plastic and waste cooking oil as a potential alternative fuel in diesel engine

The generation of plastic waste and waste cooking oil is a serious environmental concern because of worldwide waste disposal issues. At the same time, increasing demand and contemporary geopolitics make fossil fuels a significant worldwide problem. As a result, there has been an increase in demand for alternate fuel for CI engines. To overcome these twin problems can be addressed by converting waste into liquid fuels. This research explores an intriguing area by mixing waste cooking oil biodiesel and waste plastic oil to create a mixture that remarkably seems like the physico-chemical properties of diesel fuel in a society that is looking for sustainable alternatives. So, in this investigation, a ternary fuel blend of Petro-diesel, waste cooking oil biodiesel (WCOB), and waste plastic oil (WPO) was used in the diesel engine. To enhance the properties of fuel, combustion, emission, and performance parameters of diesel engines, a ternary blend of B20P20D60 was employed in the CI engine as an alternative fuel. In the ternary fuel blends, WCOB, WPO, and diesel content were 20%, 20%, and 60%, respectively. The results were compared with conventional diesel fuel, showing that the ternary fuel blend B20P20D60 has an improved brake thermal efficiency of up to 1.71% at 80% loading and reduced emissions (HC, CO, NOx) compared to conventional diesel. Because of this, the ternary blends have significant potential for use in diesel engines.