N1 Class Research Articles

Deposit reduction in a high pour point oil reservoir due to the activity of indigenous bacterial communities

Physical simulation experiments were performed to simulate the reservoir environment and evaluate deposit reduction and oil recovery by indigenous bacteria inhabiting different types of water. The bacterial communities in the samples were identified based on 16S rRNA gene amplicons. Activation resulted in the predominance of Bacillus sp. and Clostridium ultunense in the samples. The oil was investigated before and after stimulation using the GC, GC–MS and ESI FT-ICR MS techniques to evaluate and analyse the deposit reduction on different scales. The n-alkanes (n > 25) in the sample obtained from the physical simulation experiment using production fluid containing nutrients showed a 68.66% reduction, whereas the amount of wax decreased from 46.27% to 38.75%. Additionally, naphthalene and its homologues decreased by approximately 34.0%. The typical polar compounds containing N1, O1 and O2 class compounds also significantly changed, indicating a marked biodegradation of the alkyl side chains of polar compounds and the pathway of wax metabolism by indigenous bacterium indirectly. The indigenous bacteria in the production fluid more effectively degraded the wax and heavy components. Bacteria such as Acinetobacter sp., Pseudomonas sp. and Bacillus sp. played important roles in deposit reduction and were beneficial to the EOR.

TEMPORAL CHANGES OF LAND SUITABILITY DATA FOR WHEAT CULTIVATION IN IRRIGATED REGIONS- MIDDLE OF IRAQ

Al shehemia project in Wasit Governorate was selected to represent the Irrigated area in middle Iraq to study the temporal change in land suitability for wheat cultivation. Soils of the study area consist mainly, of ntisols and Aridisols soil orders .Historical Soil data were collected from previous works done in 1972 . and some soil propertic were reavoluoted at 2014. Soil and climate were evaluated for wheat cultivation according to Sys ,et al system (1993) and FAO, (1976) which developed by the Italian institute in 2012. The results showed that most of soil units are highly suitable for wheat growing with class S1 and consists about %85.34 from the total area, and %10.90 for N1and N2 classes. Land suitability for wheat cultivation increased to 92.37% for class S1 in 2014 due to the decrease in soil salinity. The results indicated that all soil units are affected by low organic carbon and this was affected on Suitability degree. The results indicated that suitability improved from 1972 to 2014 due to the decrease in soil salinity content resulted from praper management techniques that helped to leached the salts from the soils. The results showed that climate suitability for Wheat was highly Suitable (S1) for growing wheat in the study area during study period.

Transformation of Nitrogen Compounds through Hydrotreatment of Saudi Arabia Atmospheric Residue and Supercritical Fluid Extraction Subfractions

Atmospheric residue (AR) from Saudi Arabia (SZAR) was subjected to supercritical fluid extraction fractionation (SFEF) and four extractable subfractions (SFEF-1–4) and an unextractable end-cut were obtained. SZAR and SFEF-1–4 were subjected to hydrotreatment (HDT) in a continuous mini fixed-bed reactor. Three commercial catalysts were used to remove the impurity in the feedstock. The composition and structural transformation of nitrogen (N)-containing compounds were investigated. Electrospray ionization (ESI) Fourier transform–ion cyclotron resonance mass spectrometry (FT-ICR MS) was used for molecular characterization of N-containing compounds of SZAR, extractable SFEF subfractions, and HDT products. Results showed that N1 class species with high aromaticity and/or low carbon number exhibited higher catalytic hydrogenation reactivity. N1 class species with lower aromaticity were removed regardless of chain length.

Retardation effect of nitrogen compounds and condensed aromatics on shale oil catalytic cracking processing and their characterization.

Untreated shale oil, shale oil treated with HCl aqueous solution and shale oil treated with HCl and furfural were used to do comparative experiments in fixed bed reactors. Nitrogen compounds and condensed aromatics extracted by HCl and furfural were characterized by electrospray ionization Fourier transform cyclotron resonance mass spectrometry and gas chromatography and mass spectrometry, respectively. Compared with untreated shale oil, the conversion and yield of liquid products increased considerably after removing basic nitrogen compounds by HCl extraction. Furthermore, after removing nitrogen compounds and condensed aromatics by both HCl and furfural, the conversion and yield of liquid products further increased. In addition, N1 class species are predominant in both basic and non-basic nitrogen compounds, and they are probably indole, carbazole, cycloalkyl-carbazole, pyridine and cycloalkyl-pyridine. As for the condensed aromatics, most of them possess aromatic rings with two to three rings and zero to four carbon atom.

Comprehensive Characterization of Second-Generation Biofuel from Invasive Freshwater Plants by FT-ICR MS

Ultra-high resolution and mass accuracy Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) with an electrospray ionization source (ESI) was applied to characterize the bio-oils that were obtained using a micropyrolysis process of alternative biomasses from Eichornia crassipes (water hyacinth), Eichornia azurea, and Nymphaea ssp. The methods that have been developed for petroleomic analyses using FT-ICR MS data from crude oils and derivatives have been successfully employed herein to process such data for bio-oils, which are known as second-generation liquid biofuels. Class distributions and DBE versus carbon number plots (DBE × Cn) were, therefore, obtained. The class distribution for the oil obtained from water hyacinth was similar to those of classical bio-oils and appeared to be applicable as a fingerprint for bio-oils in general. The N2 and O2 classes obtained via ESI(+) and the O2 and O3 classes obtained via ESI(−) were the major classes detected in the bio-oil samples. In the DBE x Cn plot of the ESI(−)-FT-ICR MS data, the distribution of saturated and unsaturated fatty acids could be visualized, and characteristic profiles were determined for each bio-oil. It is, therefore, demonstrated that the FT-ICR MS methodology that is commonly applied to petroleomic studies can also be applied to biofuel characterization in a comprehensive “bio-oilomics” approach.

Molecular Characterization of Dissolved Organic Matter and Its Subfractions in Refinery Process Water by Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Dissolved organic matter (DOM) in oil refinery process water was fractionated by XAD-8 resin techniques into four subfractions: hydrophobic acid (HOA), hydrophobic base (HOB), hydrophobic neutral (HON), and hydrophilic substance (HIS) fractions. Negative and positive electrospray ion (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) was used to characterize the composition of DOM and its subfractions. Compounds with multi-oxygen atoms were found to be predominant in DOM by either negative or positive ESI analysis, which are similar in composition to most other treated water samples. The DOM in the HOA fraction had a similar molecular composition to that of raw process water by negative ESI analysis. The DOM in the HOB fraction had a low molecular weight (MW) when analyzed by positive ESI, and basic nitrogen compounds, such as N1 class species, were found to be predominant. The DOM in the HON fraction was predominantly O2 class species. The DOM in the HIS fraction had a relative...

Characterization of basic heteroatom-containing organic compounds in liquefaction residue from Shenmu–Fugu subbituminous coal by positive-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry

Extracts of liquefaction residue from Shenmu–Fugu subbituminous coal (LRSFSBC) were obtained by sequential extraction with petroleum ether, methanol, and carbon disulfide. They were analyzed using a Fourier transform infrared (FTIR) spectrometer and a positive-ion (PI) electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (ESI FT-ICR MS). In total, 65.37% of LRSFSBC was extracted. Aromatic C=C, C=O, and CO were identified in the extracts by FTIR analysis. Nitrogen, oxygen, and sulfur forms of LRSFSBC and the inextractable portion were characterized using X-ray photoelectron spectrometry. A series of basic N1, N2, N1O1, N1O2, N2S2, and N2O5S1 class species were identified in the extracts using ESI FT-ICR MS in PI mode. The ring plus double bond equivalents of the extracts ranges from 1–47, but is mainly below 23. In LRSFSBC some compounds are enwrapped into “capsules”, which are formed from different species associated with each other by hydrogen bonds, π–π interaction, and/or π–hydrogen bonds.

Effect of secondary oil migration distance on composition of acidic NSO compounds in crude oils determined by negative-ion electrospray Fourier transform ion cyclotron resonance mass spectrometry

The acidic and neutral NSO compounds in a series of Duvernay-sourced oils in Canada, which are believed to have migrated extensively over relatively long distances such as along the Rimbey-Meadowbrook reef trends, were characterized by negative-ion electrospray (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Heteroatomic compounds were characterized according to their class (number of nitrogen, oxygen and sulfur heteroatoms), degree of aromaticity [rings plus double bonds (DBE)] and carbon number distribution. The N1, N1O1, N1O2, N1S1, O1 and O2 classes were identified in Duvernay-sourced oils. With increasing migration distance, the relative abundance of O2, N1O1 and N1O2 showed a significant decrease, while the O1 class increased from <10% to nearly 30% of the total. With increasing migration along the Rimbey-Meadowbrook reef trend, pyrrolic nitrogen compounds (N1 class) shows an enrichment of alkylcarbazoles (DBE=9) relative to alkylbenzocarbazoles (DBE=12), and of higher homologous relative to the lower homologous. O1 compounds show a relative enrichment of those with low DBE values. Additionally, the N1O1 and N1S1 compounds show a relative enrichment of those with high DBE values, and of higher homologues compared to the lower homologues, indicating great potential for developing new migration indices.

Characterization of nitrogen compounds in coker gas oil by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry and Fourier transform infrared spectroscopy.

In this study, the classes and structures of nitrogen species in coker gas oil (CGO) are characterized by electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) combined with Fourier transform infrared (FT-IR) spectroscopy. The results demonstrate that the m/z of basic and non-basic nitrogen compounds ranges from 180 to 560 and from 200 to 460, respectively. Six basic nitrogen compounds, N1 (a molecule contains one nitrogen atom, similarly hereinafter), N1O1, N1O1S1, N1O2, N1S1, and N2, are identified by their positive-ion mass spectra, and four non-basic nitrogen compounds, N1, N1O1, N1S1, and N2, are characterized by their negative-ion mass spectra. Among these nitrogen compounds, the N1 class species are the most predominant. Combined with the data of ESI FT-ICR MS and FT-IR, the basic N1 class species are likely pyridines, naphthenic pyridines, quinolines, and benzoquinolines. The most non-basic N1 class species are derivatives of benzocarbazole. The N2 class species are likely amphoteric molecules with pyridine and pyrrole core structures.

Polycyclic Aromatic Hydrocarbons (PAHs) in Ambient Aerosols from Beijing: Characterization of Low Volatile PAHs by Positive-Ion Atmospheric Pressure Photoionization (APPI) Coupled with Fourier Transform Ion Cyclotron Resonance

Aromatic fractions derived from aerosol samples were characterized by gas chromatography and mass spectrometry (GC-MS), high temperature simulated distillation (SIMDIS), and positive-ion atmospheric pressure photoionization (APPI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), respectively. It was found that about 27 wt % compounds in aromatic fractions could not be eluted from a GC column and some large molecule PAHs were neglected in GC-MS analysis. APPI FT-ICR MS was proven to be a powerful approach for characterizing the molecular composition of aromatics, especially for the large molecular species. An aromatic sample from Beijing urban aerosol was successfully characterized by APPI FT-ICR MS. Results showed that most abundant aromatic compounds in PM2.5 (particles with aerodynamic diameter ≤ 2.5 μm) were highly condensed hydrocarbons with 4-8 aromatic rings and their homologues with very short alkyl chains. Furthermore, heteroatom-containing hydrocarbons were found as the significant components of the aromatic fractions: O1, O2, N1, and S1 class species with 10-28 DBEs (double bond equivalents) and 14-38 carbon numbers were identified by APPI FT-ICR MS. The heteroatom PAHs had similar DBEs and carbon number distribution as regular PAHs.

Identification of acidic species extracted from heavy crude oil by fourier transform ion cyclotron resonance mass spectrometry

Acidic species were extracted from heavy crude oil by alcohol-alkali solution and ion exchange resin. The acidic species in the obtained extracts and extracted crude oil were characterized by negative-ion ESI FT-ICR MS. The analytical results indicated that some class species, O2, O1, N1, N1O1, N1O2, N1S1 and O2S1 etc., were identified in the negative-ion spectrum, in which O2, O1 and N1 class showed much higher abundance than others. Compared to O1 and N1 class, O2 class could be extracted from heavy crude oil by using the two methods more efficiently, which means that a great majority of O2 class can be extracted; meanwhile, almost half of O1 and N1 class still remained in residual phase. Detailed analysis demonstrated that alcohol-alkali method was effective for extracting O2, O1 and N1 class with lower molecular weight; ion exchange method, however, was helpful to extract higher molecular weight O1 and N1 class and showed almost equal extraction selectivity to all kind of O2 class.

Characterization of Basic Nitrogen-Containing Compounds in the Products of Lube Base Oil Processing by Electrospray Ionization Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

The distribution of basic nitrogen-containing compounds in three vacuum gas oils (VGOs) with different boiling ranges and their dewaxed oils from the lube base oil refining unit of a refinery were characterized by positive-ion electrospray ionization (ESI) Fourier transform-ion cyclotron resonance mass spectrometry (FTICR MS). It turned out that the composition of basic nitrogen compounds in the samples varied significantly in DBE and carbon number, and the dominant basic N-containing compounds in these oil samples were N1 class species. N1O1, N1O2, and N2 class species with much lower relative abundance were also identified. The composition of basic nitrogen compounds in VGOs and dewaxed VGOs were correlated with increased boiling point and varied in DBE and carbon numbers. The comparison of the analytical results between VGOs and dewaxed VGOs indicated that more basic N-containing compounds in VGO with low carbon number and small molecular weight tend to be removed by solvent refining in lube base oil processing.

Transfer of Machined Patterns on an Aluminum Plate to Pyrex Glass Using Reactive Ion Etching SF&amp;lt;sub&amp;gt;6&amp;lt;/sub&amp;gt; Plasma without Masks

A method for etching the surface of a Pyrex glass substrate using the Reactive Ion Etching process without the use of masks is reported. Variations in the machined surface on an auxiliary plate, manufactured in aluminum and placed below a Pyrex glass slide, were transferred to the upper surface of the substrate. SF6 as etching gas and low pressure chamber to promote the increase of mean free path of ions were used. Two etching ratios were found, general, that affects the entire surface of the substrate, and differential, which generates the relief on the surface of the glass. Differential etching depth showed a linear behavior with respect to time; the mean differential etching rate obtained was 43 nm/min. The same phase between the auxiliary plate machining and the etched pattern on the substrate is preserved. With this technique it was possible to manufacture convex and concave surfaces; some examples are given. The arithmetic mean roughness achieved with the proposed method was found to be N1 class, ideal for the development of optical corrector plates.

The comparison of naturally weathered oil and artificially photo-degraded oil at the molecular level by a combination of SARA fractionation and FT-ICR MS

Two sets of oil samples, one obtained from different weathering stages of the M/V Hebei Spirit oil spill site and the other prepared by an in vitro photo-degradation experiment, were analyzed and compared at the molecular level by atmospheric pressure photo-ionization coupled with Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). For a more detailed comparison at the molecular level, the oil samples were separated into saturate, aromatic, resin, and asphaltene (SARA) fractions before MS analysis. Gravimetric analysis of the SARA fractions revealed a decreased weight percentage of the aromatic fraction and an increased resin fraction in both sets of samples. Molecular-level investigations of the SARA fractions showed a significant reduction in the S1 class in the saturate fraction and increase of S1O1 class compounds with high DBE values in resin fraction. Levels of N1 and N1O1 class compounds resulting in protonated ions (presumably basic nitrogen compounds) increased after degradation compared to compounds generating molecular ions (presumably non-basic nitrogen compounds). This study revealed changes occurring in heteroatom polar species of crude oils such as sulfur and nitrogen containing compounds that have not been easily detected with conventional GC based techniques.

Separation and characterization of petroleum asphaltene fractions by ESI FT-ICR MS and UV-vis spectrometer

Using heptane, toluene, and tetrahydrofuran (THF) as eluant, asphaltenes were fractionated into five fractions based on their polarity and solubility. The molecular composition of polar heteroatom species in both asphaltene and its fractions were analyzed by negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS). The application of UV-vis spectrometer in characterizing asphaltene composition and measuring asphaltene concentration was discussed. About 11.9 wt% asphaltene components adsorbed permanently on silica gel in the extrography column after excessive elution with various solvents. In negative FT-ICR MS, the mass spectra show that acidic and neutral nitrogen-containing compounds such as N1 and N1S1 mainly existe in the first three less polar fractions, while oxygen-containing compounds such as O2, O2S, O2S2, O3, and O4 show high relative abundance in more polar fractions. These results suggest oxygen-containing compounds have stronger adsorption ability with silica gel. It was observed that the double bond equivalence (DBE) distribution of N1 class species in the fractions shifted to higher values while the carbon number shifted to smaller numbers as polarity of fractions increased. This indicates that acidic and neutral N1 compounds with longer carbon chain and less aromaticity have less polarity compared with those with shorter carbon chain and stronger aromaticity. UV-vis absorbance indicats that fractions containing the most aromatic and most polar asphaltene have better absorbance at long wavelength, while the fractions that consist of least aromatic and least polar asphatlenes show high absorbance at short wavelength.

Acidic and Neutral Polar NSO Compounds in Heavily Biodegraded Oils Characterized by Negative-Ion ESI FT-ICR MS

Five heavily biodegraded tar sand bitumens from an oil column were separated into maltene and asphaltene fractions for analysis by negative-ion electrospray (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). These bitumens have an identical source, which have experienced a natural sequence of biodegradation. The polar NSO compounds in maltene fractions contain O1, S1O1, O2, S1O2, S2O2, O3, S1O3, O4, S1O4, N1, N1O1, N1O2, N1S1, and S1 classes, while the polar NSO compounds in asphaltene fractions contain O1, S1O1, S2O1, O2, S1O2, S2O2, O3, S1O3, S2O3, O4, S1O4, S2O4, O5, S1O5, S2O5, O6, N1, N1O1, N1O2, N1O3, N1S1, and N2 classes. Polar NSO compounds with stronger molecular polarity and larger molecular weight are readily fractionated into asphaltene fractions. The O2 class is prevalent in polar NSO compounds of both maltene and asphaltene fractions of all bitumen samples. The N1 class in maltene fractions is dominated by compounds with DBE values of 9, 10, 12 and 13, while the N...

Molecular characterization of nitrogen-containing species in switchgrass bio-oils at various harvest times

Nitrogen-containing species in bio-oils obtained from fast pyrolysis of switchgrass were studied using high resolution mass spectrometry at various harvest times throughout the year. Almost three hundred chemical compositions of nitrogen species were determined through efficient ionization and accurate mass information. N2 is the most abundant heteroatom class, followed by NO, N2O, NO2, and N1 compounds. Nitrogen species, especially N2 compounds, dominate the bio-oil spectra in early summer, but decrease significantly in later harvest times. From the contour plots of double bond equivalent versus carbon number and tandem mass spectrometric analysis, the major structural motif for N1 and NO class compounds are assigned as pyridine and that of N2 class compounds as imidazole. The dramatic decrease of N2 class compounds in delayed harvest bio-oils is well correlated with the decomposition of proteins, represented by imidazole as a pyrolysis product of histidine, as the senescence of the perennial plant proceeds. Some of the heterocyclic aromatic compounds are also found in gas chromatography–mass spectrometry, further supporting our analysis.

Compositional Analysis of Oil Residues by Ultrahigh-Resolution Fourier Transform Ion Cyclotron Resonance Mass Spectrometry

Ultrahigh-resolution Fourier transform ion cyclotron resonance mass spectrometry was used for compositional analysis of polar and asphaltene fractions of complex oil residues. The samples were collected before and after the processing of oil in a residue hydrocracking unit, in which the feed oil was the vacuum distillation residue of the crude oil, and the product sample was the residue collected after the processing. From the asphaltene fraction, as many as ∼26 000 peaks were detected by atmospheric pressure photoionization and more than ∼33 000 peaks by positive-ion electrospray ionization (ESI), with up to 18 distinct heteroatom classes identified. Negative-ion ESI provided complementary information through selective ionization of acidic compounds. The detected species were sorted based on heteroatom class, carbon number and aromaticity (double bond equivalence, i.e. number of rings + double bonds to carbon). The N1 class compounds were predominant in both fractions of the feed and product oils. The sulfur-containing compounds were mainly degraded or removed during the processing as expected. Vanadyl porphyrins (heteroatom class N4O1V1), detected in the asphaltene fraction of the feed oil, were not observed in the product oil fractions that is consistent with their efficient removal. Increase in the aromaticity for the most heteroatom classes was generally noticed in both polar and asphaltene fractions.

Deep Well Deposits: Effects of Extraction on Mass Spectrometric Results

Deep well deposits are solid or semi-solid components of a crude oil that are deposited during exploitation deep in the well. They may precipitate and obstruct the flow of crude oil, thus causing large economic losses. A crude oil deep well deposit was investigated using solvent extraction and electrospray ionization (ESI) Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) in both positive and negative modes. Six extraction solvents were used, covering a wide range of polarity, namely, toluene, dichloromethane, chloroform, acetonitrile, dimethylformamide, and dimethyl sulfoxide. The highest extraction efficiency (about 56%) was obtained with chloroform, whereas dimethyl sulfoxide offered the lowest efficiency (about 21%), among the six solvents. With our analytical protocol using both solvent extractions and ultrahigh-resolution mass spectrometry with electrospray ionization (ESI–MS), we were able to detect the N1 class, containing most likely pyridinic and carbazolic species, as the dominant one in the deposit, although each solvent extracted a wide variety of heterocyclic compounds of varying intensities. Although toluene, by definition, should dissolve the asphaltene content here, only a part of the sample was soluble, including mostly the N-containing classes, indicating that the deep well deposit does not consist entirely of asphaltenes. Dimethyl sulfoxide showed the lowest mass balance but one of the broadest class distributions.

INFLUENCE OF HEATING RATE ON BASIC NITROGEN-CONTAINING SPECIES CONTENT IN DACHENGZI SHALE OIL STUDIED BY POSITIVE-ION ELECTROSPRAY IONIZATION FT-ICR MASS SPECTROMETRY

Shale oil samples were produced by pyrolysis of Dachengzi oil shale, China, in a fixed bed reactor at a heating rate ranged from 5 to 20 o C min -1 under argon atmosphere, at the same final temperature of 520 o C and residence time of 20 minutes. Positive-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS) was employed to study the influence of heating rate on the basic nitrogen species content in the shale oil. The results show that increasing the heating rate results in the increase of total and basic nitrogen contents and the number of basic nitrogen species. Among all basic classes identified from positive-ion ESI FT-ICR mass spectra, the relative abundance of N1 class decreases while that of N1O1, N1O2, N1O3 and N2 classes increases as heating rate increases. With increasing heating rate the relative abundance of pyridines, whose DBE is 4, decreases significantly and that of N1 class species with DBE = 5-11 slightly, while species with DBE over 11 increase slightly. Furthermore, for pyridines and quinolines (DBE = 7) a relative obvious decrease in relative abundance is mainly observed in those species whose carbon numbers remain between 21 and 37 as heating rate increases. The relative abundance of N1O1 and N1O2 class species, whose DBE is in the range of 10-21, increases.