Hydrocarbon Oxidation Processes Research Articles

ИССЛЕДОВАНИЕ УТИЛИЗАЦИИ NI2+-СОДЕРЖАЩЕГО ОТХОДА В КАЧЕСТВЕ КАТАЛИЗАТОРА ПРОЦЕССА ОКИСЛЕНИЯ УГЛЕВОДОРОДОВ

The feasibility of utilization of spent galvanic solutions containing high concentrations of heavy metal ions as a catalyst for hydrocarbon oxidation process is shown. Characterization of the studied sulfur-alkaline wastewater (SAWW) and spent Ni2+-containing electroplating solution is presented. It is established that the sludge isolated as a result of joint treatment of SAWW from sulfide ions and spent Ni2+-containing electroplating solution from nickel (II) ions contains a significant amount of impurities of organic substances. The method of obtaining Ni2+-containing catalyst from the sludge obtained as a result of joint treatment of wastewater from chemical and galvanic production - high-temperature heat treatment at 900 °C is proposed. It is shown that 15 minutes heat treatment of sludge in air medium at 900 °C leads to almost complete removal of organic impurities from it. Diffractometric method established that the main component of heat-treated sludge is nickel (II) oxide. It has been experimentally shown that treatment of SAWW with an ozone-air mixture for 60 minutes leads to a decrease in the Chemical Oxygen Demand (COD) value by only 1604 mg O/dm3, which corresponds to a purification degree in terms of COD value equal to 11.9 %. Addition of NiO-containing sludge obtained from the joint purification of SAWW and spent Ni2+-containing galvanic solution in the concentration of 200 mg/dm3 allows to significantly intensify the process of oxidation of organic pollutants of SAWW. It has been established that the use of heat-treated NiO-containing sediment as a catalyst leads to a decrease in the COD value by 3438 mg O/dm3. At the same time the degree of purification by COD value reaches 28.1 %. It is revealed that the efficiency of treatment of SAWW by COD value as a result of ozonation process using the obtained heat-treated sludge is 16.2 % higher in comparison with non-catalytic oxidation.

Kinetic Study of <i>para</i>-<i>tert</i>-Butylcumene Oxidation in the Presence of <i>N</i>-Hydroxyphthalimide

The kinetics of the oxidation of para-tert-butylcumene to hydroperoxide by molecular oxygen in the presence of N-hydroxyphthalimide has been studied. Based on the study of the regularities in the formation of hydroperoxide and non-target reaction products, a mathematical model of the process was obtained that adequately describes the change in the main components of the reaction concentration over time. The main role of N-hydroxyphthalimide is that it converts peroxide radicals into the corresponding hydroperoxides, thereby reducing the formation of non-target reaction products by reducing the quadratic termination rate. Simultaneously formed N-oxyphthalimide radicals increase the rate of hydrocarbon oxidation. Thus, the use of N-hydroxyphthalimide in hydrocarbon oxidation processes results in an increase in the rate and selectivity of hydroperoxide formation.

Evolution and chemical characteristics of organic aerosols during wintertime PM2.5 episodes in Shanghai, China: insights gained from online measurements of organic molecular markers

Abstract. Organic aerosol (OA) is a significant part of urban fine particulate matter (PM2.5), and a lack of detailed knowledge of their sources has increasingly hindered the improvement of air quality in China in recent years, as significant reductions have been achieved in inorganic ion constituents. In this study, a wide range of organic molecular markers in PM2.5 were monitored with a bi-hourly time resolution using a thermal desorption aerosol gas chromatograph system (TAG) in urban Shanghai in winter 2019. The molecular marker data have provided a unique source tracking ability in characterizing the evolution of organic aerosols during nine wintertime episodic events. Episodes primarily influenced by local air masses were characterized with higher proportions in PM2.5 and mass increments of both primary and secondary OA. Rapid increases in both the absolute mass concentration and relative proportion were observed for primary and secondary OA markers, indicative of vehicle emissions (e.g., alkanes, hopanes, and 2,3-dihydroxy-4-oxopentanoic acid) and cooking activities (e.g., saturated and unsaturated fatty acids and C9 acids). In comparison, episodes under significant influences of transported air mass were typically associated with a predominant PM2.5 contribution from secondary inorganic aerosols and enhanced OA contribution from biomass burning activities. The latter was evident from the tracer data (e.g., levoglucosan, aromatic polycarboxylic acids, and nitroaromatic compounds). Secondary OA markers associated with later-generation products of the hydrocarbon oxidation process, such as C3−5 dicarboxylic acids, were the most deficient during local episodes, while notably enhanced during the episodes under the influence of transported air masses, reflecting the different extent and pathways of atmospheric aging processing. The ability to distinguish the variations in the OA evolution during different types of episodes demonstrates the value of online organic molecular measurements for episodic analysis. The results indicate that control of local urban sources such as vehicular and cooking emissions would lessen severity of local episodes, while regional control of precursors for secondary inorganic aerosols and biomass burning activities would reduce PM2.5 episodes under synoptic conditions conducive for regional transport.

Investigation of the influence of moisture during coal self-heating

During coal self-heating, the dehydration process and oxygen consumption by coal with different moisture content were analyzed. The oxidation process of aliphatic hydrocarbons, peroxyl radical, and nitrogen-, and sulfur-containing structures with/without water were evaluated by quantum chemical calculations. Our results indicate that the dehydration order of chemically adsorbed water is Ar-C(CH3)2OO·, C7H8S, C6H6S, C4H5N, Ar-CHO, Ar-CH2-OH, Ar-COOH, Ar-CH2OO·, and Ar-CH(CH3)OO·; the bituminous coal has a critical moisture range of 9.4–10.3% to maintain the balance with intrinsic reactivity. Below the critical moisture content, as moisture content decreases, the self-heating rate is the faster and the oxygen consumption rate is the greater; within 70 °C, without/with adsorbed water, the chemical adsorption of oxygen is respectively through sulfur- and oxygen-containing functional groups, and through C6H6S, C7H8S, Ar-CH2OH and Ar-CHO; at the temperature range of 70–110 °C, the oxidation of aliphatic hydrocarbons is the main reason for the oxygen consumption. Without adsorbed water, oxygen directly extracts H from the functional group to form ·OOH; peroxyl radical directly abstracts H from a nearby aliphatic structure. During the process, water acts as an H-transfer mediator. Adsorbed water promotes H abstraction by peroxyl radical from Ar-CH2OO· and Ar-CH(CH3)OO·, suppresses H abstraction by peroxyl radical from Ar-C(CH3)2OO·, promotes H abstraction by O2 from C4H5N and C7H8S, and suppresses H abstraction by O2 from thiophenol. The exothermic reactions mainly include the abstraction of H from C7H8S with adsorbed H2O by O2, and bond breakage in peroxyl radicals with/without adsorbed water, except Ar-CH(CH3)OO·.

Experimental and numerical investigations on extinction strain rates in non-premixed counterflow methane and propane flames in an oxygen reduced environment

The aim of this work is to contribute to the better understanding of the oxidation process of light hydrocarbons, low calorific value gas and components of natural gas in the presence of inert gases and the influence of oxygen reduction in exhaust gas recirculation situations. The extinction behavior of laminar counterflow diffusion flames of methane (CH4), ethene (C2H4) and propane (C3H8) under nitrogen diluted condition has been investigated experimentally and numerically. In the experimental set-up, a counterflow burner was employed to investigate the extinction behavior under atmospheric conditions (1 bar and 298 K). The present study highlights the non-linear influence on the decrease in the extinction strain rate (ESR) that were found with decreasing fuel content and decreasing oxygen content. The oxygen content on the oxide side was stepwise diluted with nitrogen in order to distinctly show the possible oxygen-depleted influence in the recirculation areas. Additionally, it has been shown that the distance between the nozzles has an impact on the ESR but not on the general rising trend with the increasing fuel content in the non-premixed flames. Moreover, to clarify the influence, the flame zones were visualized using a system of high-speed OH* chemiluminescence camera. It was possible to investigate the width, intensity and position of the flame front from the radical detection. This provided a comprehensive data base for the subsequent numerical validation. In order to complement the experimental investigations, extensive uncertainty analyses were conducted and a new laser-based approach for the detection of flame extinction were demonstrated for the low-visible flames. Besides the experimental study, ESRs of CH4 and C3H8 combustion obtained from the experimental measurements were compared with those predicted by the numerical simulations. The San Diego-2014 reaction mechanism was used to represent the detailed chemical reaction, in which the predicted ESRs agree well with the experimental data was shown. Additionally, the effects of radiative heat loss, molecular transport model and chemical reactions on the ESRs were studied numerically. The present results suggest that the radiative heat loss plays a minor role on the ESRs, the molecular transport model is more significant and the ESRs are quite sensitive to several key reactions.

An experimental and modeling study of ethylene–air combustion over a wide temperature range

Ethylene is an important intermediate during oxidation and pyrolysis process of higher hydrocarbons, and also serves as a fuel under practical engines. An experimental and modeling study is performed to investigate the combustion chemistry of ethylene–air mixtures under a wide range of conditions. The shock tube experiments are conducted at pressures of 1, 4, 10 and 19 atm with equivalence ratios of 0.5, 1.0 and 2.0 to determine the ignition delay times by measuring the emission signal of excited methylidyne (CH*). The ignition data under 10 and 19 atm both span a wide temperature range varying from a low temperature of 721 K to a high temperature of 1320 K. No typical negative-temperature-coefficient is observed, but the ignition at low temperatures is much shorter than the extrapolation at high temperatures. Simulations are performed and compared to the experiments using contemporary core models with consideration of a linear pressure rise of 3% /ms, but no simulation could predict the ignition trend under low-to-intermediate temperatures. Therefore, a detailed model of ethylene oxidation is proposed based on AramcoMech2.0 in the present work.The modeling behavior at high temperatures is improved by revision of addition reaction between ethylene and oxygen atom (C2H4+Ӧ). The modeling behavior at the region of low-to-intermediate temperatures is improved by detailed updating of β-hydroxyethyl oxidation (PĊ2H4OH+O2). The effect of reactions at the potential energy surface of C2H4+HȮ2 and Ċ2H5+O2 is determined, and the second oxygen addition (Ċ2H4OOH+O2) is added into current model. The present model is extensively validated by ignition delay times, concentration profiles of stable species in jet-stirred reactors and laminar flame speed under various test conditions. Sensitivity analyses are carried out to identify the dominant reactions during the auto-ignition process and laminar premixed flame propagation. Additional simulations are performed to investigate the effect of model modifications on predictions of ethane and ethanol oxidation. The present model slightly promotes the low-temperature ignition of both ethane and ethanol, and its prediction on the concentration profiles of some stable species is also improved. The proposed model of ethylene oxidation can be used as a cornerstone to develop models of larger hydrocarbon fuels.

Application of Phase Transfer Catalysis in the Esterification of Organic Acids: The Primary Products from Ring Hydrocarbon Oxidation Processes

For enhancing the cetane number (CN) of diesel fraction, the selective oxidative ring opening method was applied to upgrade ring hydrocarbons. Organic acids, one of the main products from this oxidative reaction, being esterified by the phase transfer catalysis (PTC) approach were studied. Adipic acid, benzoic acid, and phthalic acid were used as model compounds. Reaction time, reaction temperature, the amount of water, and the amount of catalyst in the esterification process were investigated and optimized using orthogonal experimental design method. The kinetics of esterification process was then conducted under the optimal condition. The types of catalysts and organic acids, the amount of catalyst and water were also investigated. The PTC esterification was one rate controlling reaction on the interface between the aqueous phase and the oil phase. Hydrophobicity is a key factor for converting benzoic acid, adipic acid, and phthalic acid to the corresponding esters. It was found that around 5–8% water is the optimal quantity for the given reaction system. Two cases of esterification processes of PTC were proposed.

Aliphatic amines modified CoO nanoparticles for catalytic oxidation of aromatic hydrocarbon with molecular oxygen

The surface modification of metal oxides using organic modifiers is a potential strategy for enhancing their catalytic performances. In this study, a hydrophobic surface amine-modified CoO catalyst with a water contact angle of 143° was fabricated. The catalyst was characterized by XRD, TGA, FT-IR, HR-TEM, and XPS. The results showed that the fabricated catalyst performed better than the hydrophilic commercial CoO nanoparticle in the process of aromatic hydrocarbon oxidation. After the amines modification, commercial CoO also became hydrophobic and improved conversion of ethylbenzene was achieved. The surface modification of CoO with amines induced the hydrophobicity property, which could serve as a reference for the design of other hydrophobic catalysts. The amines-modified CoO nanoparticles exhibited hydrophobic properties with a water contact angle of 143°, which was accompanied by better performance in the hydrocarbon oxidation process compared to that of the hydrophilic commercial CoO nanoparticles.

Production of petroleum bitumen by oxidation of heavy oil residue with sulfur

In this paper production of bitumen adding elemental sulfur at oxidation of oil residue are investigated. The objects of research were distilled residue of Karazhanbas crude oil and elemental sulfur. These oil residue characterized by a low output of easy fractions and the high content of tar-asphaltene substances, therefore is the most comprehensible feedstock for producing bitumen. The sulfur is one of the oil product collected in oil extraction regions. Oxidation process of hydrocarbons carried out at temperatures from 180 up to 210 °С without addition of sulfur and with the addition of sulfur (5-10 wt. %) for 4 hours. At 200 °С oxidation of hydrocarbons with 5, 7 and 10 wt.% sulfur within 3-4 h allows receiving paving bitumen on the mark BND 200/300, BND 130/200, BN 90/130 and BN 70/30. Physical and mechanical characteristics of oxidation products with the addition of 5-7 wt. % sulfur corresponds to grade of paving bitumen BND 40/60. At the given temperature oxidized for 2.5-3 h, addition of 10 wt. % sulfur gave the products of oxidation describing on parameters of construction grades of bitumen (BN 90/10).

Study on the Mechanism of Cold and Negative Temperature Coefficient in Natural Process of Gasoline Hydrocarbon

In this paper, the stoichiometric mechanism of gas phase oxidation process of gasoline hydrocarbons was studied through using theoretical stoichiometry. The reason of the phenomenon of cold flame and negative temperature coefficient in the reaction of hydrocarbon molecules before the flame was explained from the molecular level. During the gas phase oxidation process, the alkoxy radical RO· reacts with hydroxyl ·OH to form a relatively stable intermediate such as aldehyde (or ketone) and H2O molecules, and the free radical chain reaction process.The temperature of the reaction process is very low, while the release of a large number of heat, the formation of aldehydes (or ketones) from the excited state back to the ground state when the emission of about 400nm wavelength of light blue fluorescence.

Tailoring Ni-based catalyst by alloying with transition metals (M = Ni, Co, Cu, and Fe) for direct hydrocarbon utilization of energy conversion devices.

There is increasing demand for versatile catalysts for direct hydrocarbon utilization with the coming of hydrocarbon economy. The catalysts are required to possess both high catalytic activities and excellent carbon coking tolerance for the hydrocarbon oxidation process. In this regard, we considered Ni-based alloy catalysts, e.g. Ni-Co, Ni-Cu, and Ni-Fe, which are expected to provide synergistic effects from the high catalytic activities of Ni and the high carbon coking tolerance of transition metals. We conduct a systematic investigation of catalytic effects on the electrochemical properties and the carbon coking tolerance of the candidates. Moreover, the binding strengths of H, O, and C species with each alloy catalyst were examined via density functional theory (DFT) calculations, providing insight into the trend of catalytic activity and carbon coking tolerance. In this study, the single cell for the solid oxide fuel cell with Ni-Fe catalyst shows the best electrochemical performance, 0.81 and 0.30Wcm−2 at 700°C under H2 and C3H8, respectively, with excellent tolerance against carbon deposition.

Metalloporphyrins immobilized in Fe3O4@SiO2 mesoporous submicrospheres: Reusable biomimetic catalysts for hydrocarbon oxidation

We successfully immobilized metalloporphyrins (MeP) in mesoporous silica coating magnetite spheres. In this sense, we prepared two different classes of core@shell supports, which comprise aligned (Fe3O4-AM-MeP, MeP=FeP or MnP) and non-aligned (Fe3O4-NM-MeP, MeP=FeP or MnP) mesoporous magnetic structures. X-ray diffractometry and energy dispersive X-ray spectroscopy confirmed the mesoporous nature of the silica shell of the materials. Magnetization measurements, scanning and transmission electron microscopies (SEM/TEM), electrophoretic mobility (ζ-potential), and infrared spectroscopy (FTIR) also confirm the composition and structure of the materials. The catalysts maintained their catalytic activity during nine reaction cycles toward hydrocarbon oxidation processes without detectable catalyst leaching. The catalysis results revealed a biomimetic pattern of cytochrome P450-type enzymes, thus confirming that the prepared materials are can effectively mimic the activity of such groups.

Post - sedimentation influence on filtration capacity reservoir rock properties (Pur-Tazov oil\\gas-bearing area)

The processes of the second mineral formation (kaolinite, carbonates and micas) were identified during the post-sedimentation transformation studies in oil\\gas deposits. Besides, quartz regeneration, solid product destructive formation processes and hydrocarbon oxidation processes were -determined. Correlation analysis of the mineralogy and petrophysics data revealed the post-sedimentation influence factors on the reservoir properties of deposits. It should be noted that the second kaolinite composition increase results in water saturation and density decrease, porosity and, especially, permeability increase. Quartz regeneration and second mica formation deteriorate the reservoir properties or poorly influence them. The hydrocarbon decay and oxidation products, as well as secondary carbonate seal the void space, replace the soluble rock debris and sharply deteriorate the reservoir properties of oil andgas deposits.

INVESTIGATION OF LIQUID-PHASE OXIDATION OF NAPHTHENE-PARAFFINIC HYDROCARBONS OF BALAKHANY OIL

Liquid-phase aerobic oxidation of naphthene-paraffinic hydrocarbons at 217-330о С of diesel fraction of Balakhany oils in the presence of the mixtures of Mn, Cr salts of natural petroleum acids (MeNPA) has been investigated. The catalytic oxidation process is realized for 7 hours at temperature 135-1400C in a barbotage reactor. Samples were taken every hour and oxidized product was separated by composition in accordance with known methods. Mechanism of oxidation process of naphthene-paraffinic hydrocarbons has been studied by IR- spectroscopy. It has been found that, after 5 hours oxidation of naphthene-paraffinic hydrocarbons the yield of obtaining synthetic petroleum acids rich 16,5%, the yield of oxysynthetic petroleum acids-18%. The changes of the optical density of a carbonyl and a hydroxyl groups depending on the time were studied. It was found that the oxidation reaction should be conducted within 6 hours, as D1713(C=O) and D941(OH) after 6 hours decrease and it’s probably connected with beginning decomposition process of the acids and oxyacids.

C-H Bond Cleavage by Bioinspired Nonheme Oxoiron(IV) Complexes, Including Hydroxylation of n-Butane.

The development of efficient and selective hydrocarbon oxidation processes with low environmental impact remains a major challenge of the 21st century because of the strong and apolar nature of the C-H bond. Naturally occurring iron-containing metalloenzymes can, however, selectively functionalize strong C-H bonds on substrates under mild and environmentally benign conditions. The key oxidant in a number of these transformations is postulated to possess an S = 2 Fe(IV)═O unit in a nonheme ligand environment. This oxidant has been trapped and spectroscopically characterized and its reactivity toward C-H bonds demonstrated for several nonheme iron enzyme classes. In order to obtain insight into the structure-activity relationships of these reactive intermediates, over 60 synthetic nonheme Fe(IV)(O) complexes have been prepared in various laboratories and their reactivities investigated. This Forum Article summarizes the current status of efforts in the characterization of the C-H bond cleavage reactivity of synthetic Fe(IV)(O) complexes and provides a snapshot of the current understanding of factors that control this reactivity, such as the properties of the supporting ligands and the spin state of the iron center. In addition, new results on the oxidation of strong C-H bonds such as those of cyclohexane and n-butane by a putative S = 2 synthetic Fe(IV)(O) species that is generated in situ using dioxygen at ambient conditions are presented.

Oxidation of n-Alkane (n-C8H18) under Reservoir Conditions, in Context of Gas Mixture Injection (CO2/O2): Construction of a Kinetic Model

CO2 geosequestration or enhanced oil recovery (EOR) by CO2 injection in hydrocarbon reservoirs is suggested as a short-term solution for limiting CO2 atmospheric accumulation. In the case of oxy-combustion CO2 capture, the main annex gas associated with CO2 is O2 in important proportion (≤7%). Even if hydrocarbon oxidation processes by O2 are well-known in high-temperature–low-pressure (HT-LP) conditions, scarce data are available under reservoir conditions (high-pressure–low-temperature, HP-LT). To predict the hydrocarbon evolution in the presence of O2 in an oil-depleted reservoir, it is necessary to investigate their reactivity. As a matter of fact, a double approach combining experimentation and modeling was performed in this study. Experiments were carried out on a model compound (n-octane), by injecting O2/N2 gas mixtures in a HP-LT titanium reactor. In parallel, a detailed kinetic model for n-octane, generated by the software EXGAS, was applied. Several reactions were added, and some rate parameter...

REDUCED MECHANISM FOR COMBUSTION OF HYDROGEN AND METHANE WITH NITROGEN CHEMISTRY

A reduced chemical kinetic reaction mechanism that could be used in computational fluid dynamics (CFD) software was developed to describe the formation of nitrogen oxides and their subsequent destruction in hydrogen and/or hydrocarbon flames with or without seeding of nitrogen compounds. The research work presented here will describe the numerical work done with the application “CHEMKIN” in order to verify the quality of the reduced mechanism. The mechanism was validated through comparisons between computational data from a variety of different sources. In addition, numerical experiments were carried out to examine features of methane combustion in which the detailed mechanisms can be used to compare their response. The proposed reduced mechanism provides reasonable agreement with the studied detailed mechanisms, mainly in the species produced from the hydrocarbon oxidation process. Regarding the produced nitrogen species, the proposed reduced mechanism showed the same tendencies as the detailed mechanisms, but there is a need for a better agreement regarding the quantities.

S1110502 炭化水素の酸化過程とメンブランパッチの色との関係([S111-05]第20回卒業研究コンテスト(5),機素潤滑設計部門)

Lubricating oils have been used to various mechanics, but the performance of the machine decreases when lubricating oils are deteriorated. In recent years, oxidation degradation of the turbine basis oil becomes a serious problem in the combined cycle power plant. This problem is caused by varnish that is produced oxidation products. Therefore, it is important to detect a sign of oxidation degradation from early stage of degradation. In our laboratory, deterioration diagnosis method for lubricating oils by the colorimetric analysis of membrane patches has been developed. In the previous study, we investigated the relation between oxidation process of the turbine oils with additives and change of color of membrane patches. But, hydrocarbon oxidation process is important to understand the influence of relation among degradation of lubricating oils and color of membrane patch because lubricating oils is mainly composed of hydrocarbon. In this study, the influence of oxidation process of hydrocarbon on the color of membrane patches was investigated. And we investigated the influence of hydroperoxide on the color of membrane patches. As a result, the color of membrane patches became to brown color as oxidation of hydrocarbon. And color parameters of the membrane patch increased with increasing hydroperoxide number.

Multistage bubble suspended-bed column reactor for hydrocarbon oxidation processes

The results of testing a bubble column reactor in the oxidation of cyclododecane by air oxygen in the presence of boric acid at a temperature of 160–165°C and atmospheric pressure are given. A characteristic feature of the multistage column reactor is a number of flow circuits organized via gas-lift pipes arranged above each other. The solid phase (catalyst) is fed at the top into the upper flow circuit and further distributed among all the flow circuits over the liquid volume. The reactor may find applications in catalytic reactions and continuous processes of dissolution, flotation, contact crystallization, and hydraulic classification.

Biochemical oxidation of high-viscosity oil by indigenous soil microflora

The influence of high-viscosity crude oil from the Usa field on the oxygenase activity of indigenous soil microflora has been investigated in the laboratory. After an adaptation period, microorganisms have adapted to hydrocarbons of high-viscosity oil and the rate of biochemical oxidation has increased. Oil utilization reached 50% within 60 days of the experiment. IR analysis of residual petroleum hydrocarbons showed the appearance of absorption bands at 1070, 1165, 1730, 1270, and 3300 cm−1, which indicate the presence of a large amount of oxygenated compounds and, hence, the occurrence of petroleum hydrocarbon oxidation processes. Gas chromatographic-mass spectrometric analysis has confirmed a high biodegradation rate: utilization of acyclic saturated hydrocarbons has made 77.5%; cyclic hydrocarbons, 99.2%, alkylbenzenes, 99%; and biaromatic, triaromatic, and polyaromatic hydrocarbons, 97–99, 96, and 97%, respectively.