Addition Of Hydrocarbons Research Articles

INFLUENCE OF ORGANIC MODIFYING ADDITIVES ON QUALITATIVE INDICATORS OF PEAT ACTIVATED COAL

The Institute of Nature Management of the National Academy of Sciences of Belarus conducted extensive research on the production of activated carbons for various purposes from peat, which showed that in order to obtain highquality coals, it is necessary to use high-moor peat of a high degree of decomposition. In order to expand the resource base, it was of interest to explore the possibility of obtaining coal from peat with a lower degree of decomposition.
 Peat samples modified by products and residual products of oil refining and hardwood sawdust in granular form
 were obtained. An assessment of the physico-technical and sorption properties of the obtained granules was carried out.
 The compositions of peat with hydrocarbon additives were also studied by thermal analysis.
 Activated carbons based on compositions of peat, sawdust and some hydrocarbon wastes of petrochemical synthesis have been obtained, and their sorption and strength properties have been studied. It has been established that the use of hydrocarbon modifiers makes it possible to increase the adsorption activity of coals by 20–50 %. The introduction of sawdust into peat also increases the adsorption activity by 13–55 %, depending on the amount of additive introduced, while the strength properties and bulk density decrease in comparison with peat activated carbon.

Fates of petroleum during the deepwater horizon oil spill: A chemistry perspective

We describe the initial bulk and compound specific composition of the liquid oil spilled during the Deepwater Horizon (DwH) disaster. The emphasis is on the target hydrocarbon compounds typically found in highest concentrations and on those of concern from a toxicological perspective (i.e., the target normal alkanes and isoprenoids, and PAHs on U.S. Environmental Protection Agency’s (EPA) priority list with their alkyl homolog compounds), and/or those relevant for forensic fingerprinting of spill residues (i.e., sulfur containing PAHs and biomarker compounds). Weathering changed the oil’s composition in various environmental compartments. These compositional changes and potential environmental impacts of the remaining weathered residues are presented in this paper. Biodegradation occurred in both surface and subsurface environments while photooxidation primarily modified and removed hydrocarbons in floating oil slicks. The volatile, soluble and highly labile C1 to C10 hydrocarbons were rapidly degraded in the water column and/or emitted to the atmosphere (evaporation). The semi-volatile hydrocarbons (labile C10 to C25) that remained in the water column and floating oil on the water’s surface were lost from oil residues during weathering. The heavy nonvolatile and insoluble hydrocarbons (recalcitrant C25+) were least affected by initial weathering processes in 2010. The composition of the residual oil fraction in surface floating oil was further altered by the addition of oil soluble oxy hydrocarbons produced from photooxidation. During 2011 and 2012 the resulting highly insoluble recalcitrant C25+ oily residues remained on the shorelines, bottom sediments, or bound to suspended particulates in the water column, with detectable residues mostly returning to near pre-spill levels by 2015 to 2020. Some recalcitrant oil residues can still be found at various locations, including some coastal environments (e.g., marshes), or deep-water sediments, at very low levels, ten years after the spill.

Cyanobacteria as a Promising Alternative for Sustainable Environment: Synthesis of Biofuel and Biodegradable Plastics.

With the aim to alleviate the increasing plastic burden and carbon footprint on Earth, the role of certain microbes that are capable of capturing and sequestering excess carbon dioxide (CO2) generated by various anthropogenic means was studied. Cyanobacteria, which are photosynthetic prokaryotes, are promising alternative for carbon sequestration as well as biofuel and bioplastic production because of their minimal growth requirements, higher efficiency of photosynthesis and growth rates, presence of considerable amounts of lipids in thylakoid membranes, and cosmopolitan nature. These microbes could prove beneficial to future generations in achieving sustainable environmental goals. Their role in the production of polyhydroxyalkanoates (PHAs) as a source of intracellular energy and carbon sink is being utilized for bioplastic production. PHAs have emerged as well-suited alternatives for conventional plastics and are a parallel competitor to petrochemical-based plastics. Although a lot of studies have been conducted where plants and crops are used as sources of energy and bioplastics, cyanobacteria have been reported to have a more efficient photosynthetic process strongly responsible for increased production with limited land input along with an acceptable cost. The biodiesel production from cyanobacteria is an unconventional choice for a sustainable future as it curtails toxic sulfur release and checks the addition of aromatic hydrocarbons having efficient oxygen content, with promising combustion potential, thus making them a better choice. Here, we aim at reporting the application of cyanobacteria for biofuel production and their competent biotechnological potential, along with achievements and constraints in its pathway toward commercial benefits. This review article also highlights the role of various cyanobacterial species that are a source of green and clean energy along with their high potential in the production of biodegradable plastics.

The effect and enhancement mechanism of hydrophobic interaction and electrostatic interaction on zwitterionic wormlike micelles

The effects of hydrophobic interaction and electrostatic interaction on the structure of zwitterionic wormlike micelles (WLMs) were studied. The change of the hydrocarbon chain length and addition of cetyl trimethyl ammonium chloride (CTAC) were employed to explore the effect of hydrophobic interaction and electrostatic interaction on the wormlike micelles constructed by zwitterionic viscoelastic surfactants and sodium p-toluene sulfonate (NaPts). The experimental results show that increasing hydrocarbon chain length of zwitterionic surfactant and the addition of CTAC can increase the viscoelasticity and zero-shear viscosity of the system. The calculated length of wormlike micelles also increases. This shows that the enhancement of hydrophobic interaction and electrostatic interaction can promote the growth and entanglement of wormlike micelles. In addition, scanning electron microscope (SEM) images confirmed that CTAC makes the connection between the zwitterionic micellar layer closer. This is undoubtedly beneficial to the growth of micellar structure. Finally, this work explores the enhancement mechanism of the hydrophobic interaction and electrostatic interaction on the micelle structure.

Reduction of Surface Tension of Petroleum Using Hydrocarbon Degrading Bacterial Activity

Hydrocarbon degrading bacteria produce biosurfactants, which facilitate the biodegradation process. This is the first step towards getting access to interactions between the bacteria's hydrophilic surface and the hydrophobic surface of the hydrocarbons. Due to their amphipathic nature, biosurfactants facilitate this interaction. The focus of the study is to obtain hydrocarbon-degrading bacteria isolates and evaluate biosurfactant activity in reducing water surface tension. Hydrocarbon-degrading bacteria were isolated from contaminated marine sediment samples and consequently cultured on artificial seawater media with the addition of petroleum hydrocarbons as a carbon source. Surface tension reduction of biosurfactants was measured using a digital K20-EasyDyne tensiometer (KRÜSS: Hamburg, Germany). The study indicates that the isolates have biodegradation activity and reduced water surface tension by 22.14 mN/m, the data demonstrated that biosurfactant production was most effective on the third day of the exponential phase incubation. These studies demonstrate the effectiveness of hydrocarbon-degrading bacteria to produce biosurfactants as biodegradation agents to solve the problem of oil pollution.

Characterization of an S‐adenosylmethionine Dependent X‐Succinate Synthase Activating Enzyme

Hydrocarbons and, unfortunately, hydrocarbon waste are ubiquitous in natural and man‐made environments. It is unsurprising, then, that many microbes are capable of metabolizing hydrocarbons for use as carbon sources. Such microbes can be responsible for biodeterioration, leading to environmental damage, but paradoxically also play a role in bioremediation. As a result, an understanding of their mechanisms of action, and the ability to reproduce those mechanisms in vitro, is highly sought‐after. One such hydrocarbon degradation mechanism kicks off with the anaerobic addition of hydrocarbons to fumarate by a class of enzymes known as X‐succinate synthases (XSSs). These enzymes use a glycyl radical cofactor to accomplish this difficult chemistry under mild conditions. This cofactor must be installed by a radical S‐adenosylmethionine (SAM) activating enzyme, which has presented a hurdle to obtaining activity in vitro. The most well‐characterized XSS, known as benzylsuccinate synthase (BSS), adds toluene to fumarate to form benzylsuccinate. Unfortunately, its corresponding activating enzyme (AE) does not solubly express in E. coli, which has limited research into the mechanism of XSS activation. To circumvent this barrier, we took a genome‐mining approach to identify homologs of BSS‐AE, yielding soluble homologs that expressed well in E. coli. Using EPR spectroscopy and LC‐MS/MS, we have demonstrated that the 4Fe4S cluster within one of these AEs is able to be reduced and that this AE is able to cleave SAM. Moreover, we have expressed this particular homolog’s corresponding XSS and found that hydroalkylation activity can be reconstituted in vitro, as observed by LC‐MS/MS. It is our hope that this system will allow for a greater understanding of XSS‐AEs and their corresponding XSSs, as well as for the development of these enzymes as synthetically useful catalysts.

Visible-Light-Activated Asymmetric Addition of Hydrocarbons to Pyridine-Based Ketones

Visible-Light-Activated Asymmetric Addition of Hydrocarbons to Pyridine-Based Ketones

Nonpolymeric Citramide-Based Kinetic Hydrate Inhibitors: Good Performance with Just Six Alkylamide Groups.

The use of kinetic hydrate inhibitors (KHIs) is a well-known method for preventing gas hydrate formation in oil and gas production flow lines. The main ingredient in KHI formulations is one or more polymers with amphiphilic groups. Here, we report a series of citramide-based nonpolymeric KHIs. The KHI performance of these citramide derivatives has been studied using a synthetic natural gas mixture (forming structure II hydrate as the thermodynamically preferred phase) in slow constant cooling (ca. 1 °C/h starting from 20.5 °C) high-pressure (76 bar) rocking cell experiments. Isobutyl-substituted alkyl chains in the mono/bis(trialkyl citric acid) amide derivative gave better KHI performance than n-propyl-substituted citramide derivatives. Moreover, biscitramides with six alkylamide functional groups gave better performance than the equivalent monocitramides with three alkylamide groups. A solution of 2500 ppm of bis(tributyl citric acid) amide gave an average gas hydrate onset temperature (To) of 8.4 °C compared to 8.9 °C for a low molecular weight N-vinyl pyrrolidone/N-vinyl caprolactam 1:1 copolymer. For the bis(tributyl citric acid) amide, addition of liquid hydrocarbon (n-decane) lowered further the average To value to 6.2 °C, although this is at least partly due to lowering of the hydrate equilibrium temperature. This study demonstrates that good KHI performance can be obtained from molecules with as little as six amphiphilic alkylamide groups.

Exploring NH3 and NOx Interaction Chemistry With CH4 and C2H4 at Moderate Temperatures and Various Pressures

The oxidation of CH4/C2H4/NH3/NO/NO2 gas mixtures was studied aiming to explore the homogenous chemistry of exhaust gas from lean-operated natural gas engine. With respect to this goal, experiments were carried out with a laminar flow reactor under engine-relevant (diluted and lean) conditions over the temperature range of 600–1400 K. Four gas mixtures were designed to evaluate the effects of NO/NO2 ratio (1, 4) and pressure (0.04 and 1.0 atm) on the interaction chemistry of NH3/NOx with CH4 and C2H4. By using synchrotron vacuum ultraviolet photoionization mass spectrometry, fingerprint products for revealing interaction chemistry were identified and quantified, e.g., nitrogenous and oxygenated intermediates. The experimental results show that the NO concentrations are significantly affected by adding CH4/C2H4, changing NO/NO2 ratio and pressure. Besides, the promotion of DeNOx reactions and narrower temperature windows of NO reduction are unexpectedly observed in the presence of CH4/C2H4. To interpret the experimental observations, a detailed kinetic model was developed by integrating hydrocarbons/NH3/NOx interaction chemistry. Rate of production and sensitivity analyses indicate that the active radical pool is enriched and additional chain-branching pathways regarding NO/NO2 interconversion are activated with the addition of hydrocarbons. In the presence of both CH4 and C2H4, reaction C2H3 + O2 = CH2CHO + O was demonstrated as a crucial reaction that drives the reactivity of CH4/C2H4/NH3/NO/NO2 mixture. This is explained by the production of CH2CHO, whose dissociation generates CH2O and ultimately leads to the abundant production of active OH via the reaction sequence CH2O → HCO → HO2 → OH. The conversion kinetics of hydrocarbons, NO and NH3 under different NO/NO2 ratios and pressure, as well as the formation kinetics of oxygenated and nitrogenous intermediates was also analyzed in this work.

Enhanced wearing resistance of carbide reinforced FeCoNiCrMn high entropy alloy prepared by mechanical alloying and spark plasma sintering

Aiming to improve the wearing resistance of high entropy alloys (HEAs), this work prepared carbide reinforced FeCoNiCrMn HEA composites using mechanical alloying (MA) and spark plasma sintering (SPS) methods. The multiple carbides were introduced into the HEAs in two ways using in situ hydrocarbon additives in the MA process (HECin) and ex situ carbide additives (HECex) as carbon resources, respectively. The HECin consisted of HEA solid solution and embedded carbides of M23C6 and M7C3, leading to yield strength (YS) 1756 MPa and maximum compressive strain (MCS) 10.28%, ~14.5% stronger than the reported HEAs prepared via MA and SPS processing. The HECex introduced additional 5 wt% TaC and TiC, leading to YS 1760 MPa and MCS 7.85%. Compared with the HECin, the HECex increased hardness by ~40% (from 7.44 GPa to 9.47 GPa), but decreased friction coefficients by ~18% (from 0.32 to 0.26). The microstructure analysis of worn surface show that the HECin had adhesive wearing and slight oxidation wearing while the HECex had mainly oxidation wearing with slight adhesive wearing and fatigue wearing. This work demonstrated that the carbide reinforced HEA has superior wearing resistance properties compared with the pristine HEA and can be adopted as an effective hard coating materials.

Effect of process parameters over carbon-based ZIF-62 nano-rooted membrane for environmental pollutants separation

The paper evaluates the routes towards the evaluation of membranes using ZIF-62 metal organic framework (MOF) nano-hybrid dots for environmental remediation. Optimization of interaction of operating parameters over the rooted membrane is challenging issue. Subsequently, the interaction of operating parameters including temperature, pressure and CO2 gas concentration over the resultant rooted membranes are evaluated and optimized using response surface methodology for environmental remediation. In addition, the stability and effect of hydrocarbons on the performance of the resulting membrane during the gas mixture separation are evaluated at optimum conditions to meet the industrial requirements. The characterization results verified the fabrication of the ZIF-62 MOF rooted composite membrane. The permeation results demonstrated that the CO2 permeability and CO2/CH4 selectivity of the composite membrane was increased from 15.8 to 84.8 Barrer and 12.2 to 35.3 upon integration of ZIF-62 nano-glass into cellulose acetate (CA) polymer. Subsequently, the optimum conditions have been found at a temperature of 30 °C, the pressure of 12.6 bar and CO2 feed concentration of 53.3 vol%. These optimum conditions revealed the highest CO2 permeability, CH4 permeability and CO2/CH4 separation factor of 47.9 Barrer, 0.2 Barrer and 26.8. The presence of hydrocarbons in gas mixture dropped the CO2 permeability of 56.5% and separation factor of 46.4% during 206 h of testing. The separation performance of the composite membrane remained stable without the presence of hydrocarbons for 206 h.

Manganese-Catalyzed C(sp2)–H Addition to Polar Unsaturated Bonds

AbstractTransition-metal-catalyzed nucleophilic C–H addition of hydrocarbons to polar unsaturated bonds could intrinsically avoid prefunctionalization of substrates and formation of waste byproducts, thus featuring high step- and atom-economy. As the third most abundant transition metal, manganese-catalyzed C–H addition to polar unsaturated bonds remains challenging, partially due to the difficulty in building a closed catalytic cycle of manganese. In the past few years, we have developed manganese catalysis to enable the sp2-hydrid C–H addition to polar unsaturated bonds (e.g., imines, aldehydes, nitriles), which will be discussed in this personal account.1 Introduction2 Mn-Catalyzed N-Directed C(sp2)–H Addition to Polar Unsaturated Bonds3 Mn-Catalyzed O-Directed C(sp2)–H Addition to Polar Unsaturated Bonds4 Conclusion

Simulation of the equilibrium flow of plasma with the addition of hydrocarbons in the scope of graphene synthesis using a DC plasma torch

Graphene synthesis in the helium and argon plasma jets generated by 40 kW DC plasma torch under the pressure 350 Torr is investigated experimentally and by means of the modeling. Propane-butane mixture and methane are used as the carbon feedstock. Scanning microscopy shows that in the case of helium the structure with lateral size up to 500 nm is being synthesized. In the case of argon the morphology of graphene flakes varies from rumpled to rectified sheets with lateral size up to 2 μm. Temperature and velocity profiles are determined for the helium and argon jets using the numerical simulation. Addition of hydrocarbons into the inert plasma jets creates an environments differing in the composition and the charge concentration.

Effect of hydrocarbon addition on tip opening of hydrogen-air bunsen flames

The effect of hydrocarbon addition on tip opening of lean and stoichiometric hydrogen-air flames is studied computationally by performing two-dimensional numerical simulations. The numerical study reveals that the flame tip of the H2-air burner stabilized flame is open at lean and stoichiometric mixture conditions. The flame tip closes upon hydrocarbon addition. The tip closing is mainly affected by preferential diffusion of the multi-component mixture and the stretch effects. In the addition of light hydrocarbon (CH4), the tip closing starts at a higher percentage of hydrocarbon addition in H2-air flames. Whereas, upon the addition of heavy hydrocarbons such as propane and butane in H2-air flames, tip closing starts with a lesser amount of hydrocarbon addition. Temperature, OH mole fraction and heat release rate have been investigated, focusing on the flame structure at the tip. The tip opening regime diagram for H2–CH4-air, H2–C3H8-air and H2–C4H10-air mixtures are presented.

Homogeneous conversion of NOx and NH3 with CH4, CO, and C2H4 at the diluted conditions of exhaust‐gases of lean operated natural gas engines

AbstractUnderstanding gas‐phase reactions in model gas mixtures approximating pre‐turbine heavy‐duty natural gas engine exhaust compositions containing NO, NH3, NO2, CH4, CO, and C2H4 is extremely relevant for aftertreatment procedure and catalyst design and is thus addressed in this work. In a plug‐flow reactor at atmospheric pressure, five different model gas mixtures were investigated in the temperature range of 700‐1 200 K, using species analysis with electron ionization molecular‐beam mass spectrometry. The mixtures were designed to reveal influences of individual components by adding NO2, CH4, CO, and C2H4 sequentially to a highly argon‐diluted NO/NH3 base mixture. Effects of all components on the reactivity for NOx conversion were investigated both experimentally as well as by comparison with three selected kinetic models. Main results show a significantly increased reactivity upon NO2 and hydrocarbon addition with lowered NO conversion temperatures by up to 200 K. Methane was seen to be of dominant influence in the carbon‐containing mixtures regarding interactions between the carbon and nitrogen chemistry as well as formaldehyde formation. The three tested mechanisms were capable to overall represent the reaction behavior satisfactorily. On this basis, it can be stated that significant gas‐phase reactivity was observed among typical constituents of pre‐turbine natural gas engine exhaust at moderate temperature.

УПРАВЛЕНИЕ ЭКСПЛУАТАЦИОННЫМИ СВОЙСТВАМИ ПОВЕРХНОСТИ ДЕТАЛЕЙ МАШИН ПРИ ФИНИШНОЙ АЛМАЗНО-АБРАЗИВНОЙ ОБРАБОТКЕ С ПРИМЕНЕНИЕМ АКТИВНЫХ СОТС

There is carried out a number of experiments with the purpose of analyzing SOTS impact upon both finishing productivity, and physical-chemical state and tribological behavior of surfaces machined, and also a possibility for creation according to the results of the investigations carried out a relatively universal micro-emulsion SOTS based on existing in the Ukraine the line of oils, PAV, corrosion inhibitors, alloying additives etc. As SOTS samples there were used both well-known compouds, for example, Camix, Nope Right (USA), and carbamide having in its structure boron, boron-phosphorus-containing additive, water-solvable phosphate, tributyl phosphate (oil-solvable), concentrate SOTS tribol, having in its structure compounds of boron, nitrogen and phosphorous; ethylic ether of fatty acids; methyl ether of colza oil; Sarkozyl-O having in its structure easily-decomposable chlorine compounds. From the results obtained it is possible to draw a conclusion that during finishing in the environment of water-compatible SOTS an important role in the formation of the properties of the surface worked is played by hydrocarbon components and additives which contribute to the formation of the thinnest surface layers modified with carbon and oxygen.

УПРАВЛЕНИЕ ЭКСПЛУАТАЦИОННЫМИ СВОЙСТВАМИ ПОВЕРХНОСТИ ДЕТАЛЕЙ МАШИН ПРИ ФИНИШНОЙ АЛМАЗНО-АБРАЗИВНОЙ ОБРАБОТКЕ С ПРИМЕНЕНИЕМ АКТИВНЫХ СОТС

There is carried out a number of experiments with the purpose of analyzing SOTS impact upon both finishing productivity, and physical-chemical state and tribological behavior of surfaces machined, and also a possibility for creation according to the results of the investigations carried out a relatively universal micro-emulsion SOTS based on existing in the Ukraine the line of oils, PAV, corrosion inhibitors, alloying additives etc. As SOTS samples there were used both well-known compouds, for example, Camix, Nope Right (USA), and carbamide having in its structure boron, boron-phosphorus-containing additive, water-solvable phosphate, tributyl phosphate (oil-solvable), concentrate SOTS tribol, having in its structure compounds of boron, nitrogen and phosphorous; ethylic ether of fatty acids; methyl ether of colza oil; Sarkozyl-O having in its structure easily-decomposable chlorine compounds. From the results obtained it is possible to draw a conclusion that during finishing in the environment of water-compatible SOTS an important role in the formation of the properties of the surface worked is played by hydrocarbon components and additives which contribute to the formation of the thinnest surface layers modified with carbon and oxygen.

Numerical Analysis of Slag Transfer in the IronArc Process

The IronArc process is a novel approach to ironmaking which aims to reduce the associated {hbox {CO}}_{2} emissions. By superheating gas using electricity in a plasma generator (PG) the heat required for the process can be supplied without burning of coke. Reduction of hematite and magnetite ores is facilitated by additions of hydrocarbons from liquid natural gas (LNG). The melting and reduction of ore will produce a molten slag containing 90 pct wüstite, which will be corrosive to most refractory materials. A freeze-lining can prevent refractory wear by separating the molten slag from the refractory. This approach is evaluated in CFD simulations by studying the liquid flow and solidification of the slag using the enthalpy–porosity model in two different slag transfer designs. It was found that a fast moving slag causes a high near-wall turbulence, which prevents solidification in the affected areas. The RSM turbulence model was verified against published experimental research on solidification in flows. It was found to accurately predict the freeze-lining thickness when a steady state was reached, but with lacking accuracy for predicting the time required for formation of said freeze-lining. The results were similar when the k{-}omega SST model was used. A design with a slower flow causes more solidified material on the walls and can protect all areas of the refractory wall from the corrosive slag. A parameter study was done on the effect of viscosity, mushy zone parameter, heat conductivity and mass flow on the amount of solidified material, thickness of solidified material, heat flux, and wall shear stress. In the current geometry, freeze-linings completely protect the refractory for mass flow rates of up to 3 {text {kg}} , {text {s}}^{-1}, and are stable for the expected viscosity (0.05 to 0.3 Pa), heat conductivity (2 {text {W}}, {text {m}}^{-1},{text {K}}^{-1}), and used mushy zone parameter (10,000).

Spectroscopic Study of a Helium Plasma Jet with Hydrocarbon Additives

The results of a spectroscopic study of the conversion of acetylene and methane in a helium plasma jet produced by a direct current plasma torch are presented. The operating mode of the plasma torch corresponds to conditions that provide a high yield of carbon nanostructures. In the emission spectra recorded during the transverse observation of a 20-mm jet section following the outlet of the anode channel of the plasma torch, high-intensity Swan bands of the С2 molecule are the dominant component in the visible wavelength range. The spectra show atomic hydrogen lines of the HI Balmer series from Hα to He, numerous CI carbon lines from ultraviolet 247.9 nm to infrared 962–966 nm, and a number of HeI helium lines. The axial temperature values of the plasma jet were spectrally determined by the observed ionized carbon CII lines 283.7 nm, 392.0 and 426.7 nm. A joint analysis of the emission spectra and the mixture composition calculated in the Saha–Boltzmann approximation revealed the nature of the spatial heterogeneity of the studied He : C : H plasma jet. It is manifested by the difference in the electron temperature of the axial region of the jet, which is measured with ionized carbon lines CII (Te(0) = 12 000–14 000 K) from the vibrational and rotational temperatures of C2 molecules (TV = TR ≅ 5000 K) that emit intensely at the jet periphery. The electron density measured along the Hβ and Hγ line widths, which varies in the range of the observed jet region of ne = (4–2) × 1016 cm–3, corresponds to the ionization equilibrium in a plasma He : C : H mixture with an electron temperature close to Te measured by carbon-ion lines.

Effect of 5-membered bicyclic hydrocarbon additives on nanostructural disorder and oxidative reactivity of diffusion flame-generated diesel soot

Soot emission from diesel engines is of serious concern, as it is carcinogenic and remains suspended in air for a long time to cause adverse effects on human health and the environment. A way to reduce soot emission is by altering soot nanostructures by introducing fringe curvatures to enhance reactivity and increase oxidation. Such disorder in soot nanostructure can be initiated by the introduction of 5-membered rings into 6-membered, graphite-like soot structures. This study investigates the effect of the addition of norbornane, a saturated, 5-membered bicyclic hydrocarbon additive to diesel on the physicochemical properties, sooting propensity, structural disorders, and the oxidative reactivity of soot. The physicochemical analysis revealed that the threshold sooting index (TSI) of the blend is reduced to 29.5 at an optimum blending percentage of 10% norbornane-90% Diesel (NBD) as compared to the TSI of 37 for diesel. The analyses using XRD, Raman, HRTEM, and EDX indicated that the addition of this additive resulted in an increased soot nanostructural disorder, smaller PAH size, increased fringe curvature, and significantly greater aliphatic content in soot as compared to an unsaturated 5-membered bicyclic additive, dicyclopentadiene (DCPD). The reactivity studies confirmed that NBD soot is easily oxidized in air, since it requires a lower initial activation energy (90 kJ/mol) as compared to DCPD (120 kJ/mol) and pure diesel soots (170 kJ/mol). Thus, norbornane, a saturated 5-membered bicyclic compound, which is available as a by-product of polymer industry and in crude oil, can serve as a potential fuel additive for designing advanced fuels.