CO Hydrocarbons Research Articles

Characterizing the Transient Emission of Particles and Gases from a Single Puff of Electronic Cigarette Smoke.

This study employed high-time-resolution systems to examine the transient properties of aerosols and gases emitted from electronic cigarette (EC) puffs. Using a fast aerosol sizer, we measured particle size distributions (PSDs) across various EC brands (JUUL, VUSE, VOOPOO), revealing sizes ranging from 5 to 1000 nm at concentrations of 107 to 1010 cm-3. Most aerosols were found to be in the ultrafine range (below 100 nm), with JUUL-, VUSE-, and VOOPOO-producing aerosols with geometric mean sizes of 19.9, 47.3, and 29.4 nm, respectively. Applying the International Commission on Radiological Protection (ICRP) deposition model and assuming no further evolution of aerosols in the respiratory system, we estimated particle deposition in different respiratory regions: 45-60% in the alveolar region, 10-25% in the tracheobronchial region, and 20-35% in the extrathoracic region. The highest single-puff deposition was observed with the VOOPOO device at 60 W, depositing 180.1 ± 7.6 μg in the alveolar region. The gas emissions (CO2, NOx, CO, and total hydrocarbons) were measured at different power settings of the VOOPOO EC. Single-puff NOx and CO levels exceeded the permissible exposure limits of the Occupational Safety and Health Administration, indicating potential acute exposure risks. Higher power settings were correlated with increased gas mixing ratios, suggesting more e-liquid vaporization and possible chemical transformations at higher temperatures. These findings demonstrated significant health risks associated with ultrafine particles from high-power ECs and emphasize the need for advanced measurements to accurately assess their physicochemical properties and potential health implications.

Hydrocarbons, Hydrogen, and Organic Acids Generation by Ball Milling and Batch Incubation of Sedimentary Rocks

Pulverized rock samples are widely used in laboratory experiments, e.g., to assess microbial or abiotic processes in batch incubation tests. However, it is unclear if ball-milled samples accurately reflect in-situ conditions and if observed processes are affected by by-products artificially generated during the sample preparation procedure. As such, this study examined the effects of dry ball milling on the release of gases, which include C1-C4 hydrocarbons, carbon dioxide (CO2), hydrogen (H2), and low molecular weight organic acids (LMWOAs) from different sedimentary rocks. The experiments involved pulverization using a gas-tight zirconium oxide planetary ball mill followed by wet and dry batch incubation and thermal desorption up to 200 o C. During milling, all sedimentary rocks, except a low organic carbon sandstone sample, yielded methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), H2, CO2, and unsaturated hydrocarbons, e.g., ethene (C2H4). Sandstones only yielded H2, CH4, and CO2. Stable carbon isotope signatures of these products are similar to thermogenic gases. The gases were also detected in subsequent wet incubation experiments (after gases from milling had been removed). Additionally, formate, acetate, and citrate, were detected in all samples except for sandstone. Pyruvate, malate, and succinate were also detected in some samples. Thermal desorption products of powdered limestone, shale, and pyrite concretion samples included organic acids, such as acetate and formate, which were higher in milled samples than in crushed particles (∼1 mm). The original geological thermal maturity of the studied sedimentary rock samples was low (below “oil window”) and, thus, considerably below “gas window”, suggesting that most of the detected gases were generated during ball milling. H2 generated during ball milling may be derived from the reduction of water from fluid inclusion or phyllosilicates, involving the formation of reactive mineral surfaces or radicals. Notably, the concentrations of gaseous hydrocarbons derived from milling are relatively high and comparable to “wet” gases. At the same time, these data indicate that substantial amounts of gases and LWMOAs might be artificially generated during laboratory batch experiments with milled samples. Hence, ball milled rock samples must be used with caution if assessing (bio-)geochemical processes for natural environments.

Electrospun polyacrylonitrile nanofiber composites integrated with Al-MOF/mesoporous carbon for superior CO2 capture and VOC removal

Electrospun PAN nanofiber composites with integrated Metal-Organic Frameworks (MOFs) and mesoporous carbon (MPC) offer an efficient solution for CO2 capture and hydrocarbon removal. In this study, we synthesized a series of NH2-MIL-101(Al)@MPC composites using a solvothermal method and incorporated them into PAN nanofibers via electrospinning. The composites were characterized by FTIR, XRD, FESEM, XPS, mechanical properties and TGA, showing enhanced surface area and pore structure. NH2-MIL-101(Al) exhibited a BET surface area of 933.14 m2/g, crucial for selective absorption. The PAN/MOF@MPC nanofibers demonstrated improved mechanical properties and achieved a CO2 uptake of 6.35 mmol g−1 at 298 K and 0.55 bar. Additionally, the modified nanofibers demonstrated excellent static and dynamic adsorption capacities for volatile organic compounds (VOCs) like acetone and benzene. This study highlights the synergistic effects of combining MOFs and MPCs within electrospun nanofibers, resulting in materials with enhanced adsorption efficiency and mechanical stability. The work presents a novel approach by integrating MOF@MPCs into electrospun PAN nanofibers, significantly enhancing CO2 capture and VOC removal. This innovative combination not only improves the adsorption performance but also advances the mechanical properties of the nanofibers, showcasing a new strategy for developing high-performance materials for environmental remediation. The results offer strong potential for real-world applications in air purification and carbon sequestration.

Hydrophobic surface modification and morphology tuning of supported KNiMoS-based catalyst for synergistically enhanced higher alcohols synthesis via CO hydrogenation

MoS2-based catalysts have gained significant attention in higher alcohols synthesis (HAS) via CO hydrogenation. However, the water–gas shift (WGS) to produce CO2 in HAS is undesirable reaction, which will reduce the efficiency of carbon utilization. Here, we provide a facile strategy with hydrophobic surface modification and metal-support interaction modulation to design a series of KNiMoS/MgAl catalysts. The organic modified SiO2 shell with excellent hydrophobicity effectively shortens the residence of water formed in HAS, and further suppress the generation of CO2 and low-chain hydrocarbons. Moreover, the moderate metal-support interaction between MoS2-based active species and MgAl support can regulate the dispersion and sulfidation extent of MoS2 slabs to provide more active sites for alcohol formation. The MoS2 slabs with predominant double-layer structure enhance the C–C propagation and CO insertion in HAS. And as a result, the optimal KNiMoS/MgAl@Si(c)-5 achieves total alcohols selectivity of 74.7 %, C2+OH selectivity of 85.8 % in total alcohols, and C2+ alcohols space–time yield of 107.8 mg gcat-1h−1, where C2+ alcohols space–time yield is 3.50 and 2.71 times than those on KNiMoS/MgAl(H) and KNiMoS/MgAl, respectively. Notably, the total selectivity of CO2 and hydrocarbons is less than 23.2 %, and selectivity ratio of C2-4OH to methanol can be overturned from 1.9 to 6.0. The dependence of HAS performance on the morphology of MoS2 slabs were also demonstrated to get insight into the structure-performance relationship. This work provides a facile strategy with tunable hydrophobic surface and metal-support interaction of MoS2-based catalysts for further improvement of catalytic performance.

Efficient recovery of acetylene from quaternary mixture by a pillar-layer framework with abundant Lewis basic sites

The efficient recovery of C2H2 from the gas mixtures comprising CO2 and other light hydrocarbons is the key to realize its further value-added production. In view of their similar physical properties, reasonable design of porous physical adsorbents is expected. Here, we report a metal–organic framework bpy-NH2-CuZrF6, which possesses the suitable aperture size and abundant Lewis basic sites derived from the modified amino groups and fluorinated anions, making it the first example of achieving the efficient recovery of C2H2 from a C2H2/C2H4/C2H6/CO2 quaternary mixture. This porous material possesses an excellent C2H2 adsorption capacity (138.9 cm3/g, 298 K and 1 bar) along with considerable IAST selectivities for equimolar C2H2/CO2 (6.6), C2H2/C2H4 (6.3), and C2H2/C2H6 (6.3) simultaneously. Combined with the adsorption heats and theoretical calculations, the preferential binding with C2H2 is demonstrated. And further breakthrough experiments show that the material can efficiently purify C2H2 not only from various binary mixtures (50/50 C2H2/CO2, 50/50 C2H2/C2H4, and 50/50 C2H2/C2H6), but also from the ternary (33.3/33.3/33.3 C2H2/C2H4/CO2) and even quaternary (25/25/25/25 C2H2/C2H4/C2H6/CO2) mixtures. As a result, 32.1 L/kg and 21.9 L/kg C2H2 with fuel-grade (purity ≥ 98 %) are recovered successfully after desorption for ternary (33.3/33.3/33.3 C2H2/C2H4/CO2) and quaternary (25/25/25/25 C2H2/C2H4/C2H6/CO2) mixtures respectively. Further combined with the green scalable synthesis, good recyclability, and high stability, this microporous material is expected to have a promising prospect for practical applications.

M/BiOCl-(M=Pt, Pd, and Au) Boosted Selective Photocatalytic CO2 Reduction to C2 Hydrocarbons via *CHO Intermediate Manipulation.

Selective CO2 photoreduction to C2 hydrocarbons is significant but limited by the inadequate adsorption strength of the reaction intermediates and low efficiency of proton transfer. Herein, an ameliorative *CO adsorption and H2O activation strategy is realized via decorating bismuth oxychloride (BiOCl) nanostructures with different metal (Pt, Pd, and Au) species. Experimental and theoretical calculation results reveal that distinct *CO binding energies and *H acquisition abilities of the metal cocatalysts mediate the CO2 reduction activity and hydrocarbon selectivity. The relatively moderate *CO adsorption and *H supply over Pd/BiOCl endows it with the lowest free energy to generate *CHO, leading to its highest activity of hydrocarbon production. Specifically, the Pt cocatalyst can efficiently participate in H2O dissociation to deliver more *H for facilitating the protonation of the *CHO and *CHOH, thereby favoring CH4 production with 76.51% selectivity. A lower *H supply over Pd/BiOCl and Au/BiOCl results in a large energy barrier for *CHO or *CHOH protonation and thus a more thermodynamically favored OC─CHO coupling pathway, which endows them with vastly increased C2 hydrocarbon selectivity of 81.21% and 92.81%, respectively. The understanding of efficient C2 hydrocarbon production in this study sheds light on how materials can be engineered for photocatalytic CO2 reduction.

Co-pyrolysis of animal manure and plastic waste study using TG-FTIR analysis

In this paper, the co-pyrolysis of blends of animal manure (AM) and high-density polyethylene (HDPE) waste was investigated using micro-thermal analysis techniques. Thermogravimetry coupled with Fourier-transform infrared spectroscopy was used to study the process kinetics and potential synergistic effects during co-pyrolysis. Dynamic co-pyrolysis experiments of animal manure (AM) and polyethylene (PE) blends in proportions of (90:10 %) and (80:20 %) were conducted at heating rates of 5, 10, 15, and 20 °C/min under an N2 atmosphere. The process was analyzed and compared to the results obtained in the pyrolysis of pure components. AM and PE co-pyrolysis exhibited a synergic effect on the pyrolysis process, leading to a favorable change in the CPI pyrolysis initiation index. This was observed in the FTIR, shifting maximum devolatilization peaks by 14 °C towards lower temperatures and a lower activation energy of the main pyrolysis stage, with a decrease from 341.49±4.65 kJ/mol to 273.04±6.93 kJ/mol after the addition of 20 wt% PE to the blend. During co-pyrolysis, the main compounds observed in the FTIR absorption spectra were CO2, CO, CH4, NH3, and aromatic hydrocarbons from AM pyrolysis. Additionally, there was an increase in CH4 and short-chain hydrocarbons due to the PE pyrolysis.

Advancing Pore‐Space‐Partitioned Metal–Organic Frameworks with Isoreticular Cluster Concept

AbstractTrigonal planar M3(O/OH) trimers are among the most important clusters in inorganic chemistry and are the foundational features of multiple high‐impact MOF platforms. Here we introduce a concept called isoreticular cluster series and demonstrate that M3(O/OH), as the first member of a supertrimer series, can be combined with a higher hierarchical member (double‐deck trimer here) to advance isoreticular chemistry. We report here an isoreticular series of pore‐space‐partitioned MOFs called M3M6 pacs made from co‐assembly between M3 single‐deck trimer and M3x2 double‐deck trimer. Important factors were identified on this multi‐modular MOF platform to guide optimization of each module, which enables the phase selection of M3M6 pacs by overcoming the formation of previously‐always‐observed same‐cluster phases. The new pacs materials exhibit high surface area and high uptake capacity for CO2 and small hydrocarbons, as well as selective adsorption properties relevant to separation of industrially important mixtures such as C2H2/CO2 and C2H2/C2H4. Furthermore, new M3M6 pacs materials show electrocatalytic properties with high activity.

Advancing Pore-Space-Partitioned Metal-Organic Frameworks with Isoreticular Cluster Concept.

Trigonal planar M3(O/OH) trimers are among the most important clusters in inorganic chemistry and are the foundational features of multiple high-impact MOF platforms. Here we introduce a concept called isoreticular cluster series and demonstrate that M3(O/OH), as the first member of a supertrimer series, can be combined with a higher hierarchical member (double-deck trimer here) to advance isoreticular chemistry. We report here an isoreticular series of pore-space-partitioned MOFs called M3M6 pacs made from co-assembly between M3 single-deck trimer and M3x2 double-deck trimer. Important factors were identified on this multi-modular MOF platform to guide optimization of each module, which enables the phase selection of M3M6 pacs by overcoming the formation of previously-always-observed same-cluster phases. The new pacs materials exhibit high surface area and high uptake capacity for CO2 and small hydrocarbons, as well as selective adsorption properties relevant to separation of industrially important mixtures such as C2H2/CO2 and C2H2/C2H4. Furthermore, new M3M6 pacs materials show electrocatalytic properties with high activity.

Photothermal catalytic CO2 oxidative dehydrogenation of propane over a dual functional Pt-GaN/SrTiO3 catalyst

Photothermal CO2 oxidative dehydrogenation of propane (CO2-ODHP) is an environmentally friendly and sustainable route for propylene production and CO2 utilization. In the present work, we developed a Pt-GaN/SrTiO3 dual-functional catalyst to facilitate the reaction. The catalyst achieved propylene and CO yields of 1 mmol·gcat-1·h-1 and 1.2 mmol·gcat-1·h-1 under photothermal conditions at 320 °C, surpassing the performance of previously reported catalysts. Additionally, control experiments and in situ DRIFTS analyses corroborated that GaN and Pt were primarily responsible for the activation of C-H and CO bonds, respectively, and the photothermal route worked via a distinguished intermediate for CO2 activation in contrast to the thermal route. DFT calculations supported the reaction route involving the coupling direct dehydrogenation of propane and reverse water-gas shift reaction. The present work shines a light on the design of photothermal catalysts with dual functions, particularly for the activation of CO2 and light hydrocarbons. Additionally, it proposes a strategy to initiate high-temperature reactions at relatively lower temperatures.

Blends of Salvinia molesta oil microemulsion with diesel in an unmodified diesel engine for the simultaneous reduction of nitrogen oxide and smoke

In this study, microemulsion synthesized from chemically extracted Salvinia molesta oil with diesel was evaluated as fuel in stationary unmodified diesel engine. The microemulsions from S. molesta oil was prepared using the best combinations of 67% S. molesta oil, 15% ethanol, 13% water and 5% surfactant (span 80) and its properties were compared with that of diesel. The engine test conducted with M10, M20 and M30 blends and reported a brake thermal efficiency of 29.76% and brake specific fuel consumption of 0.3239 kg/kWh with M20. The emissions like NO and smoke reduced by 18.07% and 7.37%, respectively, with marginal increase in CO, CO2 and unburned hydrocarbon by 3.8%, 3.4% and 16.66% respectively, with M20 compared to diesel at maximum engine load of 3.73 kW. At lower engine loads with M10, M20 and M30 slightly lower CO2 emission than diesel. A drop in peak pressure and heat release rate was found to be 1.73% and 8.40%, correspondingly with M20, as that of diesel. Even though a slight reduction in brake thermal efficiency observed with M20 as compared to M10 and diesel by considering the lowest emissions of NO and smoke, it is feasible to use as promising fuel for unmodified diesel engines.

In-situ 3D measurements of water films on the natural grain surface of porous rocks

During fluid displacement, e.g. in aquifers or other fluid reservoirs such as CO2 or H2 storage sites or hydrocarbon reservoirs, water films are expected to form along the internal pore surface due to its wetting properties and capillarity. Near connate water saturation, these water films would dominate the macroscopic multiphase flow behaviour when e.g. water penetrates the porous medium. We use Atomic Force Microscopy (AFM) to study the sub-pore scale configuration of microscale water films on the rough pore surface of Ketton and Estaillades rocks, after drainage of the medium with decane. Then, we compare the results with a numerical simulation and use a film flow model to estimate the relative permeability through these films, which can be potentially used to link the water film configuration to pore- and core-scale responses. We find that the surface coverage and connectivity of the water films varies substantially with capillary pressure. This can affect the permeability of the films up to several orders of magnitude and thus potentially dictate the displacement efficiency at the onset of imbibition, when the brine phase re-enters the pore space. The novel experimental workflow proposed in this study may help future digital assessment of multiphase flow behaviour near connate saturation.

Gas-Triggered Gate-Opening in a Flexible Three-Dimensional Covalent Organic Framework.

The development of novel soft porous crystals (SPCs) that can be transformed from nonporous to porous crystals is significant because of their promising applications in gas storage and separation. Herein, we systematically investigated for the first time the gas-triggered gate-opening behavior of three-dimensional covalent organic frameworks (3D COFs) with flexible building blocks. FCOF-5, a 3D COF containing C-O single bonds in the backbone, exhibits a unique "S-shaped" isotherm for various gases, such as CO2, C2, and C3 hydrocarbons. According to in situ characterization, FCOF-5 undergoes a pressure-induced closed-to-open structural transition due to the rotation of flexible C-O single bonds in the framework. Furthermore, the gated hysteretic sorption property of FCOF-5 can enable its use as an absorbent for the efficient removal of C3H4 from C3H4/C3H6 mixtures. Therefore, 3D COFs synthesized from flexible building blocks represent a new type of SPC with gate-opening characteristics. This study will strongly inspire us to design other 3D COF-based SPCs for interesting applications in the future.

Reduction in the transport of sour gases and hydrocarbons to underlying PE-RT through thin films of PVDF

Raised temperature polyethylene (PE-RT) is being studied for use in the conveyancing of sour hydrocarbon fluids in spoolable composite pipe at temperatures above 90 °C. This grade of polyethylene swells on exposure to all hydrocarbons but specifically aromatic hydrocarbons and so there is a requirement to reduce the flux of hydrocarbons and gases into the base PE-RT. A multi-material pipe wall is one solution to reduce these fluxes but new experimental methods are required for design and validation while saturated in sour hydrocarbon fluids.In this study the simultaneous transport of species such as CO2, H2S, CH4, water vapour and aromatic hydrocarbon vapours such as toluene, xylene, IRM902 and cyclohexane were measured in real time through single films of PVDF and PE-RT and multilayer walls of PVDF/tie layer(s)/PE-RT extracted from a built (co-extruded) pipe section. The permeation test facility contained specialized gas chromatographs modified for continuous quantification of all species. The experimental methods were designed to run at 93 °C with gas pressures of 104 barg or 250 barg. Experiments were run with gas only mixtures (dry tests) and also with gas cap above a mixture of liquid hydrocarbons and water (wet tests). When possible, transport properties such as diffusion and solubility coefficients were derived from the permeation traces. The volume flow rate of all species was higher through PE-RT compared to PVDF and the volume flow rate for CO2, H2S, and CH4, increased when the gas pressure was increased from 104 to 250 barg. The gas permeability was calculated for the base polymers and also the combined multilayer structure. The flow rates estimated for a multilayer specimen using the values measured on individual films were confirmed experimentally. A simple mathematical model was proposed to derive the apparent permeability of the multilayer system and the steady-state concentration profiles across the specimen wall. Specimens were inspected for damage after a final depressurization at 70 bargmin−1. Post exposure assessment of the laminates showed that the adhesion levels were improved and the failure mode was altered from adhesive to cohesive on ageing.

Electronic energy transfer ionization in naphthalene-CO2 clusters reveals excited states of dry ice.

Electronic energy relaxation and transfer shapes the photochemistry in molecules and materials that are exposed to UV radiation in areas ranging from astrochemistry to biology. The interaction between CO2 and polycyclic aromatic hydrocarbons (PAHs) specifically, is of paramount interest in astrochemically relevant ices, the transition to renewable energy and the development of green chemistry. We investigate the vacuum UV excitation of the naphthalene-CO2 complex and observe excited states of CO2 through a newly identified molecular electronic energy transfer ionization mechanism. We evaluate the spectral development upon cluster growth with time-dependent density functional theory and show that the photoionization spectrum of naphthalene-CO2 closely resembles the photon-stimulated desorption spectrum of CO2 ice. The molecular electronic energy transfer ionization mechanism may affect the energy redistribution and charge balance in the interstellar medium significantly and therefore we discuss its implications for astrochemical models.

Insertion reactions and structural studies of [(NHC)CuH]2 with nitrogen-based substrates

The stoichiometric and catalytic reactions of Cu-H dimers supported by N-heterocyclic carbenes (NHCs) have mainly focused on the insertions of aldehydes, ketones, CO2, and unsaturated hydrocarbons. In this report, we investigated the stoichiometric reactions of dimeric [(NHC)CuH]2 (NHC = IPr*, 6Dipp) with unsaturated nitrogen-based substrates of PhN=NPh, N3Ad, pyrazine, and N2O. The spectroscopic and structural chacterizations of the resulting monomeric, two-coordinate Cu(I) complexes containing diphenyl hydrazido, triazenido, pyrazinyl, and hydroxide ligands are discussed. The hydrazido complex of (IPr*)Cu(NPh-NHPh) and triazenido complex of (IPr*)Cu(HNNNAd) are resistant to NN bond cleavage and loss of N2, respectively, to form the corresponding amido complexes even when heated at 80 °C over several hours.

Investigation of the confinement effect on fluid-phase behavior in shale oil reservoirs during CO2 injection process

AbstractDue to the confinement effect of nanopores, the fluid-phase behavior of shale oil reservoirs is much different from that of conventional reservoirs. The accurate description of the phase change characteristics of fluid in nanopores is the basis to design development plan, production system, and EOR methods of shale oil reservoirs. In this study, molecular dynamics simulation was employed to analyze the phase behavior of single-component system and hydrocarbon–CO2 mixture system in organic nanopores. The results show that the confinement effect on the phase change pressure of the single-component system is influenced by the distribution of the electron cloud. The phase change pressure of hydrocarbons with even distribution of the electron cloud would be increased, while that of CO2 would be decreased due to the instantaneous dipole moment. In addition, as the length of carbon chains increases, the confinement effect on hydrocarbons becomes stronger. When the temperature increases, the confinement effect becomes weaker. In the hydrocarbon–CO2 mixture system, when the occurrence condition changes from bulk to the nanopore of 5 nm, the bubble point pressure decreases by 39.21–68.85%, and the critical temperature and pressure decrease by 75.98% and 7.13%, respectively. On the whole, the P–T phase envelope is shrunken under the confinement effect. CO2 is much easier to be miscible with shale oil in nanopores. Moreover, full mixing and keeping in single liquid phase of CO2–hydrocarbons mixture system can reduce the adsorption of hydrocarbons on organic pore walls. Therefore, CO2 injection could be a feasible method to enhance oil recovery in the matrix of shale oil reservoirs.

Performance and emission analysis of ammonia-ethanol and ammonia-methane dual-fuel combustion in a spark-ignition engine: An optical study

In light of the pressing need to address climate change, it is imperative to take immediate action to reduce conventional hydrocarbon fuel demand. In pursuit of achieving decarbonization goals, it has become apparent that modern internal combustion engines need to adopt either carbon–neutral fuels or fuels with lower hydrocarbon content. To this end, there are several options available including alternatives such as ammonia (NH3), hydrogen (H2), methane (CH4), methanol (CH3OH), and ethanol (C2H5OH). These fuels offer the potential to be produced in a manner that is either carbon–neutral (the latter two) or entirely free of carbon emissions (the former two), making them an ideal choice for powering advanced IC engines with minimum climate impact. The use of ammonia as a fuel has the potential to significantly reduce the demand for conventional fuels and decrease the emission of harmful pollutants like CO, CO2, particulates, and unburned hydrocarbons during combustion. However, as a combustion fuel, it poses several challenges, including a low burning velocity, narrow flammability range, and instabilities arising during the combustion process. This study compared the two different dual fuel approaches, mixing ammonia-ethanol and ammonia-methane, and investigated their effect on engine performance and emissions. The experiments were conducted on a light-duty, single-cylinder, and spark-ignition four-stroke engine with an optically accessible cylinder head equipped with a port-fuel injection system. The results show that blending ethanol and methane with ammonia significantly improves its combustion characteristics due to the higher flame speed of the added components. Ammonia-ethanol blends produced reduced combustion duration, lower combustion instability, and higher engine efficiency compared to ammonia-methane blends due to the higher flame speed of ethanol. Additionally, ammonia-ethanol blends also produced higher NOx and CO2 emissions due to the higher in-cylinder temperature and lower H/C ratio. The study also applied high-speed natural flame luminosity imaging to observe the flame propagation speed for various fuel blending cases. The results found that ammonia-ethanol blends produced higher flame propagation speed than ammonia-methane blends.

Vinyl-addition polynorbornenes with glycerol and diethylene glycol moieties: Synthesis and structure-property study

A set of new norbornene-type monomers containing linear and branched substituents with three C–O–C fragments was synthesized in good yields from commercially available glycerol and diethylene glycol monomethyl ether. Vinyl-addition polymerization of the synthesized monomers was systematically studied, and highly active Pd-catalysts that made it possible to reach quantitative conversions of the monomers were suggested for their polymerization. As a result, robust thin membranes were successfully prepared directly from the polymerization mixtures in the air. Gas separation performance for a wide range of gases was evaluated for the synthesized polymers, and new valuable structure-property relationships were found. More specifically, these membranes display the facilitated transport of CO2 and solubility-controlled hydrocarbon separation selectivity. The increase in the amount of C–O–C fragments in side chains enhances these effects, but only in the case of the linear structure of the substituents. If the structure of side chains becomes branched, the gas permeability is reduced, the facilitated transport of CO2 is minimized, and the polymer becomes more susceptible to plasticization by butane. The facilitated transport of CO2 is due to the specific dipole-quadrupole interaction between CO2 molecules and polymer matrix. For the studied polymers, the contribution of this specific interaction to the solubility of CO2 achieves 64 %. The significant influence of alkyl tails in side chains on gas transport properties was also observed. To achieve better gas separation performance, it is desirable to incorporate short and rigid alkyl tails. Thus, among substituents containing ether moieties, linear oligoethylene glycols with methyl tails seem to be the most promising side-chain substituents for the macromolecular design of CO2-selective polymeric membrane materials. The results obtained were considered along with NMR, TGA, DSC, DMA, and WAXD data.

A field-study of the feasibility of the use of biodiesel in the marine industry

ABSTRACT The International Maritime Organization is making multiple efforts to reduce greenhouse gas and air pollutant emissions. However, it is difficult to achieve this because of the absence of technological developments. Consequently, there is an urgent need to develop alternative fuels. In this study, marine gas oil and biodiesel were blended at ratios of 0%, 5%, 10%, and 20% to assess their applicability to ships (Component analysis, metal corrosion, and storage stability) and potential for emission reduction (engine performance, environmental effects, and engine durability). The composition of the test fuels meet the ISO 8217:2017 standard. Metal corrosion was insignificant for carbon steel, iron, aluminum, and nickel, but not copper. Storage stability showed no sludge generation or fuel separation, although biodiesel experienced some discoloration owing to its high oxygen content. Engine performance showed no significant differences between marine gas oil and biodiesel. Emissions of NOx increased with higher biodiesel blending ratios, whereas SOx, CO, CO2, and Total hydro carbons decreased. Engine durability was good throughout the 160 hours sea trial. This study demonstrated that even at a 20% biodiesel blending ratio exceeding the 7% ratio suggested by ISO 8217:2017, can be safely used as a long-term marine fuel.