Petroleum Residues Research Articles

Production of Bitumen Modified with Low-Molecular Organic Compounds from Petroleum Residues. 3. Tar Modified with Formaldehyde

The chemical modification of tar with formaldehyde as 37% aqueous solutionhas been studied in the presence of the catalysts. Hydrochloric acid, sulfuric acid, sodium hydroxide and acid tar were used as the catalysts. The effect of the catalyst nature and amount, as well as temperature, process time and initial components ratio on the softening point, penetration, brittle point and adhesion to crushed stone has been determined. The structure of the modified tars was confirmed by IR spectroscopy. The structural-group composition was determined. Arene-formaldehyde resins have been synthesized on the basis of toluene and modified tars using hydrochloric acid as a catalyst. The synthesized resins were characterized using IR spectroscopy. The chemistry of the tar modification with formaldehyde has been proposed.

Dissolved organic matter production from herder application and in-situ burning of crude oil at high latitudes: Bioavailable molecular composition patterns and microbial community diversity effects

Chemical herders and in-situ burning (ISB) are designed to mitigate the effects that oil spills may have on the high latitude marine environment. Little information exists on the water solubilization of petroleum residues stemming from chemically herded ISB and whether these bioavailable compounds have measurable impacts on marine biota. In this experiment, we investigated the effects of Siltech OP40 and crude oil ISB on a) petroleum-derived dissolved organic matter (DOMHC) composition and b) seawater microbial community diversity over 28 days at 4 °C in aquarium-scale mesocosms. Ultra-high resolution mass spectrometry and fluorescence spectroscopy revealed increases in aromaticity over time, with ISB and ISB+OP40 samples having higher % aromatic classes in the initial incubation periods. ISB+OP40 contained a nearly 12-fold increase in the number of DOMHC formulae relative to those before ISB. 16S rRNA gene sequencing identified differences in microbial alpha diversity between seawater, ISB, OP40, and ISB+OP40. Microbial betadiversity shifts were observed that correlated strongly with aromatic/condensed relative abundance and incubation time. Proteobacteria, specifically from the genera Marinomonas and Perlucidibaca experienced −22 and +24 log2-fold changes in ISB+OP40 vs. seawater, respectively. These findings provide an important opportunity to advance our understanding of chemical herders and ISB in the high latitude marine environment.

Organic compounds residues investigation in groundwater at Assiut governorate, Egypt

However the adverse impact of organic pollutants and their occurrence in the food chain in Egypt, scarce studies have dealt with these pollutants in water resources. The aim of this work is the non-targeted organic compounds investigation in Assiut Governorate groundwater, Egypt. Thirty-four samples were collected and analyzed for their chemical oxygen demand (COD), and three of them were selected for the non-targeted survey of organic compounds by GC-MS instrument. The COD values ranged from 0 to 216 mg O2/l, indicating the pollution of some samples with organic compounds. The GC-MS results indicated the occurrence of plastic, petroleum, pesticides and pharmaceutical residues in the analyzed samples. The source of these compounds may be household effluents, improper disposal of wastewater through absorption septic tanks, improper application of panned pesticides and leakage from fuel tanks. Finally, the groundwater needs targeted investigation of organic pollutants in the study area.

Investigation of the hydrodynamics in the regenerator of fluid catalytic cracking unit integrated by chemical looping combustion

Oil refineries are responsible for 4–6% of global CO2 emissions, and 20–35% of these emissions released from the regenerator of Fluid Catalytic Cracking (FCC) units, which are the essential units for the conversion of heavier petroleum residues (vacuum gas oil) into more valuable products. Chemical looping combustion (CLC) has been recently proposed to mitigate the CO2 emissions released from the regenerator of FCC units with a lower energy penalty. However, a detailed experimental and modelling investigation is still necessary in order to identify the hydrodynamics in the regenerator of chemical looping combustion integrated with fluidised catalytic cracking (CLC-FCC). A computational fluid dynamic (CFD) study was conducted to understand the hydrodynamic behaviours of gas-solid two-phase flow in the regenerator of the CLC-FCC unit, based on a three-dimensional multiphase model (Eulerian-Eulerian) with the kinetic theory of granular flow.The results provide a useful insight into regenerator hydrodynamics, in terms of oxygen carrier modified FCC catalysts and FCC coke distribution profiles, in the regenerator of CLC-FCC. The conventional drag models (Syamlal-O'Brien and Gidaspow) predict a bed density profiles of a dense phase (250–300 kg/m3) at the dense phase (0–0.25 of h/H), and a dilution phase from h/H = 0.25 to 0.50 of regenerator. The bed density profile is indistinguishable from the industrial data provided for conventional FCC regenerators. The fluidisation gas (CO2) passes through the centre of the regenerator where the fluidisation gas splits the catalyst particles from the centre to the walls, to create a dilute particle phase in the centre and a dense particle-phase near the wall, which is one of the characteristic flow regimes in circulating fluidised bed reactors. The particles in the centre demonstrate an upward flow trend with a particle velocity above 3.0 m/s while the dense particles near the wall tend to go down with relatively low particle velocity of <0.5 m/s, which creates vortexes and a non-uniform particle distribution in the regenerator. The distribution of the fluidising gas provides better mixing of solid particles in the entrance and the optimisation of the superficial gas velocities (1.0 m/s) to create a distributed flow regime with developed vortexes through the dense and dilute phases. Furthermore, the laminar and turbulent flow models demonstrated no significant differences in terms of axial bed density profile in the regenerator of the CLC-FCC concept. These findings demonstrated that the hydrodynamics of catalysts in the CLC-FCC regenerator successfully predicted with CFD modelling and the prediction results aligned well with the conventional FCC regenerator.

Production of Bitumen Modified with Low-Molecular Organic Compounds from Petroleum Residues. 2. Bitumen Modified with Maleic Anhydride

The possibility of modification of BND 60/90 bitumen produced at JSC Ukrtatnafta (Kremenchuk, Ukraine) with maleic anhydride has been considered. The effect of maleic anhydride amount, process time and temperature on the operating characteristics of modified bitumen has been studied.

Thermochemical Recycling of Waste Plastics by Pyrolysis: A Review

The increasing demand for plastics for their widespread applications has ultimately resulted in accumulation of substantial plastic waste, which remains a concern due to limited efforts, inadequacy, and environmental distresses of conventional techniques for waste plastics remediation. The enhanced production of raw materials for polymer syntheses has a dual impact on our ecosystem by causing rapid depletion of nonrenewable petroleum resources and waste generation. To address this situation, researchers have adopted advanced thermochemical recycling processes to produce intermediate products of the petrochemical industries including monomers, fuels, and other value-added products. Such practices can potentially serve the purpose of a circular economy. This review aims to cover the recent highlights in the field of waste plastics pyrolysis including critical observations from the past to provide precise understanding. Consequently, the reactivities and product distributions for plastic feeds, pyrolysis reactors, roles of catalysts, and effects of operating parameters on reactivity and selectivity have been covered. Coprocessing of plastic waste with radioactive materials, biomass, and heavy petroleum residue is also discussed. Furthermore, an overview on kinetics and mechanistic aspects of plastic pyrolysis is presented with a discussion on relevant analytical techniques. The applications of pyrolysis oil as a fuel or fuel additive are comprised in a separate section. Lastly, comparisons of existing chemical recycling technologies, summaries of commercial operations, and future projections are provided.

Carbonaceous aerosols in urban Chongqing, China: Seasonal variation, source apportionment, and long-range transport

Seventy-seven PM2.5 samples were collected at an urban site (Chongqing University Campus A) in October 2015 (autumn), December 2015 (winter), March 2016 (spring), and August 2016 (summer). These samples were analysed for organic carbon (OC), elemental carbon (EC), and their associated char, soot, 16 PAHs, and 28 n-alkanes to trace sources, and atmospheric transport pathways. The annual average of OC, EC, char, soot, ΣPAHs, and Σn-alkanes were 20.75 μg/m3, 6.18 μg/m3, 5.43 μg/m3, 0.75 μg/m3, 38.29 ng/m3, and 328.69 ng/m3, respectively. OC, ΣPAHs, and Σn-alkane concentrations were highest in winter and lowest in summer. EC, char, and soot concentrations were highest in autumn and lowest in winter. Source apportionment via positive matrix factorization (PMF) indicated that coal/biomass combustion-natural gas emissions (23.8%) and motor vehicle exhaust (20.2%) were the two major sources, followed by diesel and petroleum residue (21.1%), natural biogenic sources (17.7%), and evaporative/petrogenic sources (17.2%). The highest source contributor in autumn and winter was evaporative/petrogenic sources (30.6%) and natural biogenic sources (34.5%), respectively, whereas diesel engine emission contributed the most in spring and summer (32.1% and 38.0%, respectively). Potential source contribution function (PSCF) analysis identified southeastern Sichuan and northwestern Chongqing as the major potential sources of these pollutants. These datasets provide critical information for policymakers to establish abatement strategies for the reduction of carbonaceous pollutant emissions and improve air quality in Chongqing and other similar urban centres across China.

Silicon Single Walled Carbon Nanotube-Embedded Pitch-Based Carbon Spheres Prepared by a Spray Process with Modified Antisolvent Precipitation for Lithium Ion Batteries

Si is regarded as a next-generation anode material for high-energy density lithium-ion batteries (LIBs). However, Si-based anode materials cause intractable problems that result in ceaseless capacity decay and poor cyclic performance. In this study, two types of industrial wastes, Si powder (from the photovoltaic industry) and pitch (from petroleum residue), were selected as the active material and carbon source, respectively, for preparing a Si single-walled carbon nanotube (SWCNT)-embedded carbon composite. A good conductive pathway was created by the SWCNTs, and the inner voids in the composite increased its conductivity and provided extra space for accommodating the volume expansion of lithiated Si. In addition, a porous pitch-based spherical composite with embedded Si and SWCNTs was fabricated through a designed one-step process using a combination of the spray-drying and antisolvent precipitation techniques and a series of thermal treatments. The cycling test results revealed that the composite showed the high reversible specific capacities of 2001 mAh g–1 at 1 A/g (0.5 C) with a retention of 66.1% and 1682 mAh g–1 at 1 A/g (0.5 C) with a retention of 55.6% after the 100th and 200th cycles, respectively. These results imply that the pitch-derived soft carbon and SWCNTs provided an excellent conductivity, and the porous structure of the composite accommodated the stress produced by the Si expansion.

Production of Bitumen Modified with Low-Molecular Organic Compounds from Petroleum Residues. 1. Effect of Solvent Nature on the Properties of Petroleum Residues Modified with Folmaldehyde

The possibility of petroleum residues (tar and oxidized bitumen) modification with formaldehyde (37 % aqueous solution) has been studied at the temperature of 393±3 K for 3 h in the presence of organic solvent and using hydrochloric acid as a catalyst. Toluene, p-xylene, naphta solvent and n-octane were used as the solvents in the amount of 0–40 wt % relative to the initial material. By means of IR spectroscopy the resin-like compounds affecting the operational properties of petroleum residues have been detected. These compounds are formed as a result of formaldehyde reaction with residue components and solvent molecules.

Structurally explicit composition model of petroleum vacuum residue

The molecular modeling of fuels requires comprehensive composition data: names and molar fractions of the components. For fuels like petroleum residues, two problems arise: first, state-of-the-art analytical techniques can not detect the full list of molecule names, and second, this list would lead to a number of components that is unmanageable. A comprehensive composition can be modeled by the use of stochastic models that generate a combination of digital molecules whose global properties are close to the properties of the fuel under study. The current models only offer a set of representative molecules, from which an enormous number of different structures may be inferred. Different structures result in multiple initial conditions of a detailed kinetic model or conflicting results in a computational chemistry software. For an end user, it would be easy to build impossible structures that violate the rules of chemistry while interpreting the representative structures. To address these difficulties, a computer program was created which is able to model composition of any vacuum residue with unambiguous molecules. A custom-made molecule core library and a “molecular sieve” have been introduced, which consents generation of species that are proven to exist experimentally. Data analysis of the experimental results of three vacuum residues was performed and compared with simulation results. SARA separation simulation was executed for model validation. Detailed molecular class fractions of the simulation were provided; many distributions that are challenging to obtain by the use of experimentation were presented to better understand the molecular structures inside a vacuum residue.

THE EFFECT OF ALKALI TREATMENT ON IMPROVING THE MECHANICAL PROPERTIES OF RAMIE (BOEHMERIA NIVEA), SUGAR PALM (ARENGA PINNATA), AND COIR (COCOS NUCIFERA) FIBERS

In line with economic growth, material requirements in the industrial sector will increase. Industries are required to use materials that are safe for human health, environmentally friendly and utilize local raw materials. Currently, industries in general still use synthetic materials based on petroleum residues that contain many hazardous chemicals. Therefore, natural fiber has the potential to be used as a substitute for synthetic materials, especially in Indonesia which is rich in natural fibers resources. This will have an impact on the socio-economy of the local community so that it can grow the rural economic sector. Natural fibers have high economic value that can be used for various raw material needs for strategic industries. A good natural fiber processing mechanism will produce products that can be marketed globally with guaranteed product quality. This research analyzes the effect of alkali treatment of ramie, sugar palm and coir fiber on the increase in mechanical properties of the fiber. The mechanical properties were analyzed through tensile strength testing of single fiber according to ASTM D3822 standard using a textechno favigraph machine. In addition, this research is supported by data from thermogravimetric analysis (TGA), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The results showed that the fibers that had been given an alkali treatment had better mechanical properties compared to untreated fibers. Increased tensile strength of fibers was observec after being treated with alkali for ramie 81%, sugar palm 52% and coir 56%. The advantage of this alkaline treatment method is that no heating is involved and the treatment procedures are more practical compared to other methods.

Gasification Plants for Chemical Production: The Impact of Carbon Utilization on CO2 Capture from the Facility

Coal and other disadvantaged fuels such as petroleum coke and refinery bottoms can be used for the production of chemicals around the world. Coal is an established feedstock in gasification and has been the primary focus in markets like China, where the use of coal to chemicals is needed due to limited access to oil and natural gas reserves. Disadvantaged feedstocks such as petroleum coke and heavy residues are currently experiencing a shift in market utilization. New legislation on criteria pollutants in countries like India and IMO2020 legislation are reducing the size of petroleum coke and residue feedstock end markets. The need to dispose of these disadvantaged feedstocks has created new project opportunities for gasification plants. However, with the new opportunities come increasing pressures to lower the CO2 but also increasing the opportunity to take advantage of CO2 emission reduction benefits and/or to deploy the CO2 for enhanced oil recovery. Air Products provides high quality technical solutions as a technology supplier, process integrator and operator. This paper will present our unique perspective on the amenable streams for CO2 capture within the gasification plant, thoughts on how the technologies are developing to further reduce the overall CO2 footprint of a coal to syngas facility, and what the major driving forces are present in selecting technologies and process options. Gasification produces CO2 as a natural byproduct of the reactions taking place in the gasifier to produce syngas as well as downstream water gas shift reactions. The high temperatures and pressures that various gasification and shift processes can operate under provide potential capture points in the plant flowsheet depending on the quantity and purity of CO2 needed. In addition, product syngas requirements dictate the purity and CO to H2 ratio of the product syngas which has a direct influence over the amount of CO2 available to capture from the product syngas streams. Pressurized CO2 sources are a more cost effective way to capture high levels of CO2. As compared to SMR technologies in which approximately 50% of the CO2 is at pressure, solid and liquid gasification technologies contain almost all of the CO2 within the pressurized syngas stream. The amenable product stream locations vary in quantity, purity, and pressure of CO2. Therefore, the degree of capture from the plant is an important variable when selecting the location and technology employed to capture at a specific facility. Gasification also has the advantages of heat recovery from the process to produce steam which can offset the steam demand from low pressure CO2 sources like on purpose boilers. Heat recovery and integration options are core to producing an economic solution to the CO2 capture. Various technologies exist for the removal of CO2 from gasification plants. The methanol based Rectisol process is one technology employed in gasification plants for the effective removal of CO2 from the pressurized gasification syngas streams. It is a proven technology for purifying the syngas stream, but it is not the only technology which can be employed to capture CO2. Numerous studies on decarbonized fuels have outlined Rectisol as well as other acid gas removal technologies for power production. In this paper, the focus will be on revisiting these standby technology options and introducing additional technologies, like Air Products Sour PSA technology, that provide options to capture various levels and purities of CO2, for the solid or liquid feedstock to syngas markets. Currently, Air Products has formed a joint venture with the Luan Coal Group to operate a large-scale gasification plant which converts coal to liquids. The carbon in the coal does not leave the facility as CO2 as in decarbonized power production processes. A significant portion of the carbon is incorporated into the final product from the syngas. This utilization of carbon in the products influences the amenable envelope of technologies that can be used to capture CO2 from the plant. Maximizing the carbon that resides in product molecules provides an interesting twist on previous decarbonized power carbon capture studies. Maximizing carbon utilization provides insight into how to design the balance of plant and what technologies could be developed that would directly impact the material balance as well as the CO2 emissions from the overall facility. Air Products is uniquely positioned to analyze the technical challenges of capturing CO2 from gasification facilities. Identifying cost effective solutions to individual opportunities and the technical driving force influencing design choices will be discussed in this paper.

Development of semi-synthetic catalyst based on clay and their use in catalytic cracking of petroleum residue

Two semi-synthetic clay-based catalysts were prepared. These catalysts were obtained by incorporating lanthanum oxide (Cat1) and chromium oxide (Cat2). They were then tested for catalytic cracking of a heavy petroleum residue (fuel). The two formulations were carried out in the presence of silica to improve their acidity then underwent an acid activation. The catalysts obtained were characterized by various methods (XRD, FTIR, ICP-OES, SEM). The results showed that the incorporation of oxides and the addition of silica improves the structural characteristics of the final products. The support used was a kaolinite rich clay, having a specific surface area of 15.26 m2/g and acidity of 14 meq/g. These values increase, respectively, to 456.14 m2/g and 50 meq/g for Cat1 and to 475.12 m2/g and 57 meq/g for Cat2. The influence of the type of oxide incorporated, the specific surface area, the porosity and the acidity of the catalysts on their catalytic activity was studied. The nature of the oxide used proved to be decisive on the quality of the catalyst. Thus Cat1, prepared with lanthanum oxide, showed the best performance in cracking the petroleum residue achieving a conversion rate of 74.13% compared to 66.53% for cat2.

Soil Contamination Assessments from Drilling Fluids and Produced Water Using Combined Field and Laboratory Investigations: A Case Study of Arkansas, USA.

Rotary drilling for oil and natural gas uses drilling fluid for lubrication of the bit, to seal off unstable shale layers, and floating out rock cuttings. Drilling fluid is a water–clay chemical mixture. Produced water is a water–sand chemical mixture. Land farming is a common disposal technique of drilling fluid and produced water. In the land farming process, amendments of fluid are repeatedly applied to the soil surface. Plant growth and soil chemical properties may be altered by additions of drilling fluid, because of alkalinity, salinity, trace elements, and petroleum residue contained in waste. The objective of this study was to determine the change in soil pH, electrical conductivity (EC), total nitrogen and carbon, and extractable nutrient levels following the land application of drilling fluid and produced water. The study was a comparison of three plots with similar soil properties and conditions. The three study plots had various levels of drilling fluid and produced water applications. The data show a major difference from field-to-field for EC, Na, and Cl levels. The EC and salt levels increased with additional applications of drilling fluid and produced water. The percent total nitrogen values and plant available P levels were very low in all fields. High EC and salt values, coupled with low N and P levels, would be detrimental to plant growth and development. To successfully vegetate this land-farm site, application of N and P fertilizer would be required. This study help to give a better understanding of practical ways to land-farm drilling fluid and produced water in a fashion that both minimizes environmental issues and is economically feasible in Arkansas. Thus, this research will provide important information for soil contamination management and contributes on understanding of the responses of soil properties to drilling fluid and produced water in the future.

Waste plastic for increasing softening point of pitch and specific surface area of activated carbon based on the petroleum residue

Pyrolysis fuel oil (PFO) is used for the manufacturing of high-purity pitch for carbon precursor due to its high carbon content, high aromaticity, and low heterogeneous element and impurity content. Pitch is commonly classified with its softening point, which is most considerable physical property affecting to various characteristics of the carbon materials based on pitch, such as electrical and thermal conductivity, mechanical strength, and pore property. Hence, the softening point should be controlled to apply pitch to produce various carbon materials for different applications. Previous studies introduce reforming process under high pressure and two step heat treatment for the synthesis of pitch with high softening point from PFO. These methods lead to a high process cost; therefore, it is necessary to develop a process to synthesize the pitch with high softening point by using energy effective process at a low temperature. In this study, waste polyethylene terephthalate (PET) was added to control the softening point of PFO-based pitch. The pitch synthesized by the heat treatment with the addition of PET showed the softening point higher than that of the pitch synthesized with only PFO. The softening point of PFO-based pitch synthesized at 420 °C was 138.3 °C, while that of the pitch synthesized by adding PET under the same process conditions was 342.8 °C. It is proposed that the effect of the PET addition on the increase in the softening point was due to the radicals generated from thermal degradation of PET. The radicals from PET react with the PFO molecules to promote the polymerization and finally increase the molecular weight and softening point of the pitch. In addition, activated carbon was prepared by using the pitch synthesized by adding PET, and the results showed that the specific surface area of the activated carbon increased by the addition of PET. It is expected that the pitch synthesis method with PET addition significantly contributes to the manufacture of pitch and activated carbon.

Endocrine disruptors also function as nervous disruptors and can be renamed endocrine and nervous disruptors (ENDs).

Endocrine disruption (ED) and endocrine disruptors (EDs) emerged as scientific concepts in 1995, after numerous chemical pollutants were found to be responsible for reproductive dysfunction. The World Health Organization established in the United Nations Environment Programme a list of materials, plasticizers, pesticides, and various pollutants synthesized from petrochemistry that impact not only reproduction, but also hormonal functions, directly or indirectly. Cells communicate via either chemical or electrical signals transmitted within the endocrine or nervous systems. To investigate whether hormone disruptors may also interfere directly or indirectly with the development or functioning of the nervous system through either a neuroendocrine or a more general mechanism, we examined the scientific literature to ascertain the effects of EDs on the nervous system, specifically in the categories of neurotoxicity, cognition, and behaviour. To date, we demonstrated that all of the 177 EDs identified internationally by WHO are known to have an impact on the nervous system. Furthermore, the precise mechanisms underlying this neurodisruption have also been established. It was previously believed that EDs primarily function via the thyroid. However, this study presents substantial evidence that approximately 80 % of EDs operate via other mechanisms. It thus outlines a novel concept: EDs are also neurodisruptors (NDs) and can be collectively termed endocrine and nervous disruptors (ENDs). Most of ENDs are derived from petroleum residues, and their various mechanisms of action are similar to those of "spam" in electronic communications technologies. Therefore, ENDs can be considered as an instance of spam in a biological context.

Comparison of coking additives obtained from different types of oil stock

Coke producers often face a shortage of valuable grades of coals, i.e. coking coals. This paper examines the possibility to obtain a coking additive by applying delayed coking to various types of heavy petroleum residues. The paper also gives a comparative description. Five types of heavy petroleum residue from the KINEF oil refinery were used in the experiments that aimed to produce carbon material. They included vacuum residue ELOU-AVT-6, vacuum residue S-1000 resultant from the hydrocracking process, visbreaker bottoms from the S-3000 unit, and two mixtures of the ELOU-AVT-6 unit products: a mixture of vacuum residue and third vacuum cut; and a mixture of vacuum residue, third vacuum cut and atmospheric residue. The carbon material obtained from all the above types of raw materials was analyzed for quality; an X-ray diffraction analysis was carried out; and the interplanar spacings d002 and d110 were calculated, as well as the linear sizes of Lc and La crystallites. The coking additive obtained instead of the typical petroleum coke was found to meet the specification. Thus, the volatile matter content in it is within the range from 15 to 25 wt%. This additive can be used in steel production instead of coking coal. The coking additive from a mixture of vacuum residue, third vacuum cut and atmospheric residue has the highest content of volatile matter (19.30%), while the coking additive from the visbreaking residue from the S-3000 has the lowest volatile matter content (16.15%). The latter is due to the fact that the primary petroleum material was subjected to light thermal cracking. It is shown that as the composition of the heavy petroleum residue changes, so do the properties of the resultant coking additive: a higher fraction of the low-boiling components in the feedstock is associated with a higher volatile matter content; the carbon materials produced from vacuum residue have a higher microhardness; the coking product produced from the visbreaker bottoms has a lower porosity compared with the product obtained from the vacuum residue. This research was carried out as part of a governmental assignment of the Ministry of Education and Science of the Russian Federation in the framework of the following research project: 0792-2020-0010 “Fundamentals of innovative processing techniques to obtain environmentally-friendly motor fuels and innovative carbon materials with variable macro- and microstructure of the mesophase from heavy hydrocarbon materials”. The research was carried out at the laboratory of the Shared Knowledge Centre of the Saint Petersburg Mining University.

Fractionation of a vacuum residue with a mixture of CO2-toluene as a method for characterizing heavy petroleum feedstocks

ABSTRACT The characterization of the feedstock is an important analytical task in the modeling and development of processes for upgrading of petroleum residues. This work presents the results of fractionation of the vacuum petroleum residue by extraction using a mixture of CO2 and toluene as a solvent. Fractionation was carried out by changing the ratio of components in the mixture by successively increasing the concentration of toluene in the composition of the CO2 stream from 0% to 50%. As a result of separation of the vacuum residue, nine fractions of the extract with a yield of 83.1% were obtained.

Obtaining Pure Vanadyl Porphyrins from Heavy Petroleum Residue to Create Catalysts for Various Processes

Asphaltenes and resins from petroleum vacuum residue were shown to be the promising raw materials for obtaining pure vanadyl porphyrins. Vanadyl porphyrins are recovered from petroleum objects via the extraction of dimethyl formamide (DMFA) followed by purification on a chromatographic column using silica gel and sulfocationite. The composition of the obtained vanadyl porphyrins was studied by means of mass spectrometry with matrix assisted laser desorption/ionization (MALDI) and high performance liquid chromatography (HPLC). Thus obtained metalloporphyrins can be used as a basis to create catalysts for various chemical processes, which may serve as an alternative to their synthesis.

Spatiotemporal distribution and source variations of hydrocarbons in surface sediments from the Pearl River Estuary, Southern China

Variations in hydrocarbon composition and concentration are essential for the assessment of its source and environmental health in estuarine environments. This study aims to reveal the spatial and temporal distribution of multiple hydrocarbons in surface sediments of the Pearl River Estuary, and to further determine various sources of these hydrocarbons. Surface sediments were taken monthly from four sites along a spatial transect from the Pearl River Estuary in a whole year by using a gravitational bottom sampler. A series of bulk parameters including the grain size, total organic carbon content, and total nitrogen content were measured. Hydrocarbons in sediments were extracted and analyzed by the gas chromatography-mass spectrometry. The abundances of higher plants and phytoplankton-derived n-alkanes, petrogenically derived pristane, phytane, hopanes, and steranes with geological configuration, and anthropogenically derived hydrocarbons, including linear alkylbenzenes and polycyclic aromatic hydrocarbons all showed decreasing trends towards the coastal ocean. In contrast, the diatom-derived C25 highly branched isoprenoids increased towards saline sites. Monthly fluctuations of aliphatic and aromatic hydrocarbons at the estuarine mouth were smaller than the upstream freshwater sites, where high monthly variation (up to fivefold) was observed for most of the hydrocarbons detected. This study showed substantial monthly and spatial variations of hydrocarbons in the surface sediments of the Pearl River Estuary. Distribution and composition of sedimentary hydrocarbons indicate mainly anthropogenic inputs (e.g., petroleum residues and synthetic detergents) and terrestrially higher plants, followed by aquatic inputs.