Vanadium In Crude Oil Research Articles

Investigation of demetallization of Ni and V in crude oil using spherical polyelectrolyte brushes with adjuvant

Nickel and vanadium in crude oil adversely affects the quality of petroleum coke and refining process. Polymer brushes bearing high-density ligands have shown promising nickel removal ability. In this work, submicron polybutadiene (PB) grafted by aminodithio- carbamate acrylamide (PAMDTC@PB) was prepared and characterized by the infrared spectroscopy, dynamic light scattering, and elemental analysis. Based on results of molecular simulation, PAMDTC was selected as ligand molecule at first. Then the nickel and vanadium removal rates by PAMDTC@PB and traditional polyacrylic acid brushes (PAA@PB) were evaluated through the electric desalination process, both in the model and real oil samples. The result shows that S atom in AMDTC is most likely to chelate with metal porphyrin compounds and AMDTC molecule presents highest chelating activity. Compared with PAA@PB, the removal rate of Ni and V porphyrin compounds with the aid of PAMDTC@PB increases significantly, with an optimized removal rate of 46.91 % and 56.81 %. To achieve better metal removal efficiency and higher utilization rate of prepared polymer brushes, sodium dimethyl dithiocarbamate (SDD) is introduced into the electric desalination process as a adjuvant. The results indicate that the addition of SDD leads to a increment of 10–30 % to the removal rate of Ni and V and a reduction of brush dosage by 200–400 ppm in the electric desalination process, exhibiting great potential of industrial applications of novel desalination process with adjuvant.

Determination of iron, nickel, and vanadium in crude oil by inductively coupled plasma optical emission spectrometry following microwave-assisted wet digestion

The complexity of crude oil samples is the primary difficulty in reliable quantitation of their metal contents. However, substantial advances in sample digestion procedures have been presented as a result of the utilization of microwave radiation. Herein, a new method based on microwave-assisted digestion (MW-AD) for the decomposition of crude oil samples has been developed for efficient determination of iron, nickel, and vanadium by inductively coupled plasma optical emission spectrometry (ICP OES). Yttrium was used as an internal standard to achieve as accurately as possible quantitation. The digestion efficiency was optimized using various HNO3 concentrations (14.5, 9.1, 6.5, and 4 mol L−1) and different volumes of H2O2 by determining the residual carbon content (RCC) and residual acidity (RA) of the final digests. The obtained results revealed that 9.1 mol L−1 HNO3, 2 mL H2O2, and sample mass of 300 mg were the appropriate compromise conditions for efficient digestion and suitable final digests since RCC values and RA were below 10% and 35%, respectively. The MW-AD method was successfully validated by the analysis of samples spiked with the target metals at different concentration levels. The results demonstrated a satisfactory recovery in the range of 95–104.2% with intra-day and inter-day relative standard deviation of less than 10%. The method was also applied to the determination of the analyte metals in crude oil samples, and the results were compared with those obtained by the application of the ASTM D5708 method as a reference method.

Detection of iron oxide nanoparticles in petroleum hydrocarbon media by single-particle inductively coupled plasma mass spectrometry (spICP-MS)

Engineered iron oxide (Fe3O4) nanoparticles (NPs) were synthesized with a silica shell using a modified alkylsilane approach with o-xylene, as a hydrocarbon media, and transmission electron microscopy (TEM) and single-particle inductively coupled plasma mass spectrometry (spICP-MS) were used to determine the particle size of the Fe3O4 core diameter. In contrast, mass concentrations of the Fe3O4 particles were determined using spICP-MS, using helium (He) as a collision gas to control spectral interferences from ArO and CaO on Fe at m/z 56. Different cell gas flow rates (3, 3.5, and 4 mL/min) and NP’s solution dilution factors from 1:20,000 up to 1:60,000 were investigated; He flow rate of 4 mL/min and a dilution factor of 1:20,000 were found as optimum. The spICP-MS method was calibrated by using gold nanospheres (polystyrene-coated) in toluene as reference material. For the engineered Fe3O4 nanoparticles, TEM. Results gave a (63 ± 6 nm) value for the Fe2O3 core diameter, while spICP-MS was 61.1 ± 4.5 nm (n = 36), demonstrating the excellent agreement among methods. The method was applied for the analysis Fe oxide NPs in petroluem hydrocarbon materials and data compared with TEM. Two standard reference materials (SRMs); NIST 2717a sulfur in residual fuel oil and NIST 8505 vanadium in crude oil were selected. spICP-MS results agreed pretty well among these techniques. These findings suggest that spICP-MS could be useful to characterize Fe-containing particles in complex solution media, such as petroleum hydrocarbons. Graphical abstract

Sequential extraction procedure for the separation of Ni and V species in crude oil and analysis by ETAAS, GC–MS, and IR

The determination of nickel and vanadium in crude oil has been evaluated in several scientific studies because these elements can contribute to equipment corrosion, the contamination of catalytic processes, and environmental pollution. Many studies have focused on the evaluation of the total concentration of these elements. However, although it is important to know the total elemental concentration to determine the chemical composition of a sample, this does not yield information about the amount of potentially toxic compounds that may be associated with different macromolecules present in the sample. Here, we report the development of a sequential extraction procedure for the separation of nickel and vanadium species. To determine the total concentration of Ni and V, samples, as well as a certified reference material (NIST – SRM 1634C), were acid digested and analyzed by electrothermal atomic absorption spectrometry (ETAAS). The separation of the species was performed by column chromatography with silica gel as the stationary phase, and hexane (fraction 1), toluene (fraction 2), dichloromethane (DCM) + methanol (fraction 3), and methanol (fraction 4) as the eluents. The extracts obtained in each fraction were analyzed by ETAAS, gas chromatography–mass spectrometry (GC–MS), and infrared (IR) measurements. The experimental results showed that the total concentrations of the elements in the crude oil were between 7.4 and 14.3 µg g−1 for Ni and 9.8 to 14.6 µg g−1 for V. The analysis of SRM 1634C showed that 89% of Ni and 103% of V were recovered. The GC–MS analysis showed the following elution order: saturated compounds and aromatics (fraction 1), aromatic and cyclic compounds (fraction 2), aromatic compounds (fraction 3), and polar compounds (fraction 4). The results obtained by ETAAS showed that 100% of the Ni and V contained in crude oil can be separated in three different extracts. However, the IR spectra and GC–MS analysis allowed us to conclude that Ni and V are associated with compounds containing nitrogen and oxygen that were not identified by gas chromatography.

Determination of Vanadium in Crude Oil and Some Petroleum Products Spectrophotometrically

Determination of Vanadium in Crude Oil and Some Petroleum Products Spectrophotometrically

Multivariate optimization of a procedure employing microwave-assisted digestion for the determination of nickel and vanadium in crude oil by ICP OES

This work presents the optimization of a sample preparation procedure using microwave-assisted digestion for the determination of nickel and vanadium in crude oil employing inductively coupled plasma optical emission spectrometry (ICP OES). The optimization step was performed utilizing a two-level full factorial design involving the following factors: concentrated nitric acid and hydrogen peroxide volumes, and microwave-assisted digestion temperature. Nickel and vanadium concentrations were used as responses. Additionally, a multiple response based on the normalization of the concentrations by the highest values was built to establish a compromise condition between the two analytes. A Doehlert matrix optimized the instrumental conditions of the ICP OE spectrometer. In this design, the plasma robustness was used as chemometric response. The experiments were performed using a digested oil sample solution doped with magnesium(II) ions, as well as a standard magnesium solution. The optimized method allows for the determination of nickel and vanadium with quantification limits of 0.79 and 0.20μgg−1, respectively, for a digested sample mass of 0.1g. The precision (expressed as relative standard deviations) was determined using five replicates of two oil samples and the results obtained were 1.63% and 3.67% for nickel and 0.42% and 4.64% for vanadium. Bismuth and yttrium were also tested as internal standards, and the results demonstrate that yttrium allows for a better precision for the method. The accuracy was confirmed by the analysis of the certified reference material trace element in fuel oil (CRM NIST 1634c). The proposed method was applied for the determination of nickel and vanadium in five crude oil samples from Brazilian Basins. The metal concentrations found varied from 7.30 to 33.21μgg−1 for nickel and from 0.63 to 19.42μgg−1 for vanadium.

Distribution of Nickel and Vanadium in Venezuela Crude Oil

The distribution of nickel and vanadium in five fractions (saturated hydrocarbons, aromatic hydrocarbons, soft resin, hard resin, and asphaltene) of Venezuelan 380 crude oil was studied. The method of column chromatography separation was used two times. Furthermore, the UV-vis spectroscopy was used to characterize the role of metals in different fractions. Results showed that the content of vanadium in crude oil was much higher than nickel. The metals mainly existed in resins (~20%) and asphaltene (~70%). UV-vis spectroscopy had also confirmed the presence of vanadium porphyrins in resins and asphaltene.

Catalytic Voltammetric Determination of Vanadium in Crude Oil at Carbon Nanotube Paste Electrode

A catalytic voltammetric method for the determination of vanadium(V) at a multi-wall carbon nanotube paste electrode (MWCNT-PE) in a 4-(2-pyridylazo)-resorcinol(PAR)-bromate system is proposed. The voltammetric response of V(V)-PAR complex at MWCNT-PE was significantly enhanced because of a catalytic cycle consisting of electrochemical reduction of V(V) ion in the complex and subsequent chemical oxidation of the reduction product of V(V) by bromate. In pH 2.70 H2SO4 solution containing 5.0×10-6 mol•L-1 PAR and 3.0×10-2 mol•L-1 KBrO3 without any preconcentration, the linear sweep voltammetric peak current of the catalytic wave was proportional to the vanadium concentration in the range of 8.0×10-9 to 3.0×10-6 mol•L-1. The detection limit was 2.5×10-9 mol•L-1. Using the proposed method, the vanadium concentration in crude oil was evaluated and the results were compared with those of atomic absorption spectrometry.

Determination of nickel and vanadium in crude oils by electrothermal atomic absorption spectrometry and inductively coupled plasma atomic emission spectroscopy after mineralization in an autoclave

A comprehensive technique for determining Ni and V in crude oils in a wide range of their concentrations is described. The procedure involves ETAAS, ICP-AES, and autoclave sample preparation. The optimal conditions for the mineralization of oil samples in Ankon-AT2 analytical autoclaves in a mixture of HNO3 and H2O2 are found. Oil and condensates of oil- and gas-bearing basins are taken as objects of investigation. The concentrations of Ni and V in these systems are estimated and the regularities in the distributions of Ni and V are revealed.

Fractionation and speciation of nickel and vanadium in crude oils by size exclusion chromatography-ICP MS and normal phase HPLC-ICP MS

The coupling of size exclusion chromatography (SEC) and normal phase (NP) HPLC using entirely organic mobile phases (tetrahydrofuran, xylene) with inductively coupled plasma mass spectrometry (ICP MS) were developed and investigated for the molecular distribution of nickel and vanadium in crude oils. The metal species were fractionated by SEC using three columns in series with the increasing porosity (100, 1000 and 100000 A) covering the molecular mass range (in eq. polystyrene) between 300 and 2 × 106 Da. The resolution achieved allowed the discrimination of at least three classes of Ni and V species with varying proportions of the metals as a function of the origin of crude oil, crude oil fraction (asphaltene, maltene) and dilution factor. Normal phase HPLC-ICP MS allowed the separation of the porphyrin-type fraction as well as separation of the remaining species into three distinct fractions. The metal species in the SEC fractions were found to be sufficiently stable to be collected and preconcentrated to allow the development of a bidimensional chromatography SEC-NP-HPLC-ICPMS for the probing of the metal distribution in crude oils in terms of molecular weight and polarity.

Feasibility of using solid sampling graphite furnace atomic absorption spectrometry for speciation analysis of volatile and non-volatile compounds of nickel and vanadium in crude oil

A method for the direct determination of volatile and non-volatile nickel and vanadium compounds in crude oil without previous treatment using direct solid sampling graphite furnace atomic absorption spectrometry is proposed. The crude oil samples were weighed directly onto solid sampling platforms using a microbalance and introduced into a transversely heated solid sampling graphite tube. In previous work of our group losses of volatile nickel and vanadium compounds have been detected, whereas other nickel and vanadium compounds were thermally stable up to 1300 and 1600 °C, respectively. In order to avoid this problem different chemical modifiers (conventional and permanent) have been investigated. With 400 μg of iridium as permanent modifier, the signal started to drop already after two atomization cycles, possibly because of an interaction of nickel (which is a catalyst poison) with iridium. Twenty micrograms of palladium applied in each determination was found to be optimum for both elements. The palladium was deposited on the platform and submitted to a drying step at 150 °C for 75 s. After that the sample was added onto the platform and submitted to the furnace program. The influence of sample mass on the linearity of the response and on potential measurement errors was also investigated using four samples with different nickel content. For the sample with the lowest nickel concentration the relationship between mass and integrated absorbance was found to be non-linear when a high sample mass was introduced. It was suspected that the modifier had not covered the entire platform surface, which resulted in analyte losses. This problem could be avoided by using 40 μL of 0.5 g L −1 Pd with 0.05% Triton X-100. Calibration curves were established with and without modifier, with aqueous standards, oil-in-water emulsions and the certified reference material NIST SRM 1634c (trace metals in residual fuel oil). The sensitivity for aqueous standards and emulsions was close to that for SRM 1634c, making possible the use of aqueous standards for calibration. The limits of detection and quantification obtained for nickel and vanadium under this condition were found to be 0.02 and 0.06 μg g −1, respectively, for both elements, based on 10 mg of sample. Nickel and vanadium were determined in the samples with (total Ni and V) and without the use of Pd (thermally stable compounds), and the concentration of volatile compounds was calculated by difference. The results were compared with those obtained by high-resolution continuum source graphite furnace atomic absorption spectrometry by emulsion technique; no significant differences were found for total Ni and V at the 95% confidence level according to a Student's t-test.

Spectrophotometric determination of vanadium in crude oil

Spectrophotometric method has been developed for the determination of vanadium after derivatization with 2-pyrrolealdehyde phenylsemicarbazone (PPS). The linear calibration curve was obtained with 2.5– 20 μ g / ml vanadium. Copper(II), cobalt(II), iron(II) and palladium(II) could also be determined separately using PPS with linear calibration curves within 2.5–12.5, 5–15, 2.5–15 and 1– 5 μ g / ml at 362, 355, 355 and 365 nm, respectively. The vanadium in crude oil was determined with relative deviation (RSD) of 2.5–5.0%. The methods have been applied for the analysis of copper from copper wires, cobalt from pharmaceutical preparation and palladium from palladium on barium sulphate with RSD within 2.6–4.5%.

Speciation analysis of volatile and non-volatile vanadium compounds in Brazilian crude oils using high-resolution continuum source graphite furnace atomic absorption spectrometry

A method is proposed that makes possible determining total and “thermally stable” vanadium in crude oil without prior separation, and to calculate “volatile” vanadium by difference. The volatile fraction is believed to be largely vanadyl porphyrine complexes. The method is based on the unsurpassed background correction capability of high-resolution continuum source graphite furnace atomic absorption spectrometry (HR-CS GF AAS), which allows pyrolysis temperatures as low as 300 °C to be used. The samples were prepared as oil-in-water emulsions, and aqueous standards emulsified in the same way were used for calibration. Total vanadium has been determined using a pyrolysis temperature of 400 °C, and “thermally stable” vanadium using a pyrolysis temperature of 800 °C. The content of total vanadium in 12 Brazilian crude oil samples was found to be between less than 0.04 and about 30 mg kg −1. The volatile fraction was between 5 and 51% of the total content, and there was no correlation between the total and the volatile vanadium content. The limits of detection and quantification were 0.04 and 0.12 mg kg −1 of V in crude oil, respectively, based on a mass of 2 g of oil in 10 mL of emulsion. The precision was better than 4% at the 3 mg kg −1 level and better than 1.5% at the 30 mg kg −1 level of V in crude oil.

Palladium as chemical modifier for the stabilization of volatile nickel and vanadium compounds in crude oil using graphite furnace atomic absorption spectrometry

It has been observed in previous work using high-resolution continuum-source atomic absorption spectrometry that up to 50% of the nickel and vanadium in crude oil, most likely non-polar nickel and vanadyl porphyrin complexes, was already lost at pyrolysis temperatures >400 °C, whereas the rest of the analyte was stable up to at least 1200 °C. In this work we were investigating the use of a chemical modifier in order to avoid these low-temperature losses and also to make possible a differential determination of the volatile analyte fractions. Oil-in-water emulsions, using Triton X-100 as surfactant, were used for easy sample handling. A mass of 20 μg of Pd, introduced into the graphite tube and thermally pretreated prior to the injection of the emulsion, was found to efficiently prevent any low-temperature losses of nickel and vanadium from crude oil samples up to pyrolysis temperatures of 1200 °C and 1450 °C, respectively. The best characteristic mass obtained was m0 = 16 pg for Ni and m0 = 33 pg for V. The limits of detection and quantification were 0.02 μg g−1 and 0.065 μg g−1, respectively, for Ni, and 0.06 μg g−1 and 0.17 μg g−1, respectively, for V in oil, based on an emulsion of 2 g of oil in 10 mL. The precision expressed as relative standard deviation (n = 9) for a crude oil containing about 5 μg g−1 Ni and 3 μg g−1 V was 2.0% and 3.1% for Ni and V, respectively. The accuracy of the procedure was verified by analyzing the certified reference material NIST SRM 1634c, trace metals in fuel oil, and the research material RM 8505, vanadium in crude oil.

Determination of Nickel and Vanadium in Crude Oil Using Wavelength Dispersive X-Ray Fluorescence Spectrometry and a Tight Standardization Method*

AbstractMetallic impurities present in crude oils lead to the rapid deactivation of catalysts used in refineries and a drop in the yield of oil products. The determination of these impurities is therefore of primary importance. The conventional and most widely used methods to determine trace metals in oils and petroleum products are chemical analysis methods such as atomic absorption spectrometry (AAS) and inductively coupled plasmaoptical emission spectrometry (ICP-OES). Sample preparation for these methods includes decomposition of the crude sample by dry ashing and combustion of the oil sample followed by chemical treatment of the dry ash residue (ASTM, 1983; Fassel et al., 1976). Major drawbacks of chemical analysis methods are the length of time required to prepare the sample and the possibility of losing trace metallorganic compounds in the form of volatile compounds.

Rapid simultaneous determination of sulfur and vanadium in crude oil using X-ray fluorescence

A rapid instrumental method for simultaneous determination of sulfur and vanadium in crude oil by X-ray fluorescnece using radioisotope exciting radiation and semiconductor detector is discussed. Changes in crude oil density or composition did not affect the sulfur determinatio, while the vanadium concentration measurement was influenced by the sulfur content of the oil. Crude oil samples were taken from different Iraqi fields and analysed by this method.

Procedure for determination of vanadium in crude oils by ion exchange method

Procedure for determination of vanadium in crude oils by ion exchange method

Evaluation of Carbon Rod Atomizer for Routine Analysis of Vanadium in Crude Oil by Atomic Absorption Spectroscopy

Abstract The Carbon Rod Atomizer (CRA) was evaluated for routine trace analysis of vanadium in crude oil by atomic absorption spectroscopy with a carbon (graphite) tube as a micro-furnace. Two crude oil samples were analyzed, both by standard addition and standard working curve methods, and the results confirmed by analysis with flame atomic absorption spectroscopy using a fuel-rich nitrous oxide-acetylene flame. Because of the relative involatility of vanadium at the temperature of the CRA, quantitative recoveries of vanadium in crude oil occur only when the vanadium content of the sample injected into the CRA does not exceed the limit of about 1 × 10−8 g. A sensitivity (weight/1% absorption) of 7.0 × 10−11 g and detection limit (signal-to-root-mean-square-noise equal to two) of 6.9 × 10−12 are reported.