Corrosion Of Oil Pipelines Research Articles

EXTRACTION OF NAPHTHENIC ACIDS FROM ACIDIC PETROLEUM CRUDE OIL UTILIZING 2-METHYLIMIDAZOLE WITH THE AID OF Ca/Al2O3 AND Ce/Al2O3 CATALYSTS

Naphthenic acids (NAs) is one of the major sources of corrosion in oil pipelines and distillation units in crude oil refineries. Removing NA compounds from crude oils is regarded as one of the most crucial processes in heavy oil upgrading. Catalytic deacidification method had been developed in order to reduce the total acid number values in crude oil. Crude oil from Petronas Penapisan Melaka had been chosen to be studied with original total acid number (TAN) of 2.43 mg KOH/g. The parameters used were different catalyst calcination temperatures, catalyst loading, reagent concentration, reaction times and reaction temperature. Acid removal agent of 2-methylimidazole in ethanol and monometallic calcium and cerium doped with alumina were used as a catalyst. The results showed that with the aid of catalyst, the TAN can be reduced to lower than 1 mg KOH/g. Catalyst of Ca/Al2O3 calcined at 900oC gave a better reduction than Ce/Al2O3 with 83.54% of TAN reduction (2.43 to 0.4) for Ca/Al2O3 catalyst and 71.19% (2.43 to 0.7) for Ce/Al2O3 catalyst. The best catalyst underwent several characterization methods such as X-Ray Diffraction Spectroscopy (XRD), Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetry Analysis (TGA-DTA) for its physicochemical properties. It can be concluded that catalytic deacidification method was effective in extracting NAs from the crude oil thus lowered the TAN value to less than 1 mg KOH/g.
 Keywords: Naphthenic acids; Crude oil; Catalysts

Characterization and identification of corrosive bacterium isolated from petroleum product transporting pipelines

Corrosion is the main feature of the oil pipelines destruction. Biocorrosion has been detected in various industries, especially in the oil industry. The rusted pipes samples were obtained from the Gandomkar petroleum pipeline station, Iran. For screening the corrosion producing bacteria, the samples were cultured in the selective culture medium, manganese agar and Iron oxidizing agar incubated at 30 °C for 18 h. The purified individual colonies were subjected to macroscopic, microscopic and molecular examinations, respectively. The cultivation of corrosion based material on manganese agar isolated cream-coloured colonies, convex with the surrounding smooth. The microscopic examinations showed Gram-negative coccobacilli. Based on macroscopic, microscopic and molecular examinations the bacterial isolate was identified as Stenotrophomonas maltophilia strains PBM-IAUF-4 with the accession number of KU145280.1 in Gene Bank. The cultivation of corrosion based material on Iron oxidizing agar isolated cream-coloured colonies cream-coloured colonies that had swarming, convex. The results showed Gram-negative bacilli. Based on macroscopic, microscopic and molecular examinations the bacterial isolate was identified as Kluyvera intermedia strains PBM-IAUF-1 with the accession number of KU145277.1 in Gene Bank. This is the first report of isolation and identification of corrosion-producing bacteria from, Gandomkar, Iran. The first isolated bacterium was identified as Stenotrophomonas maltophilia. The second isolated bacterium was identified Kluyvera intermedia. Both bacteria were isolated for the first time in the world from pipeline corrosion samples. This study confirmed the role of bacteria in the corrosion of oil pipelines.

Design of Nano-Inhibitor of Dichlorobenzene and It's Adduct and Study of Its Structural and Electronic Properties: DFT Calculations

Corrosion in oil pipelines is one of the biggest problems in the oil sector companies because of the high cost resulted from repairing the corroded parts, or replace it with another non-corroded ones, so, in this research, we study the design of nano-inhibitor and study of its structural and electronic properties of dichlorobenzene molecule (C6H4Cl2) and the effect of adding groups of Hydroxy on those properties, density functional theory (DFT) at B3LYP level with (6-31G) basis sets. The study included four new molecules, which are including monohydroxy dichlorobenzene molecule, dihydroxy dichlorobenzene, trihydroxy dichlorobenzene, and tetrhydroxy dichlorobenzene. The structural and electronic calculations have been done by using Gaussian 09 program and Gaussian View in DFT calculations. The geometry optimization using both methods for dichlorobenzene (nano-inhibitor) and group’s Hydroxy molecules has been found in good agreement with experimental data. While the electronic properties included calculate total energy, ionization potential, electron affinity, chemical potential, electronegativity, electrochemical hardness and electronic softness for molecules under study. These results show that the energy gap reduced with the increase of the number of groups; also, the electron affinity and electronegativity for dichlorobenzene molecule Ben-Cl-2OH are the lowest, while the chemical potential be the highest for the same inhibitor. Nano-inhibitor result reduces corrosion of internal surfaces of tubes that used for transporting oil and gas to the importance of these molecules in terms of their high ability for interaction. Those dichlorobenzene can restrain corrosion from claiming steel toward framing an inactive layer for this molecule on the metal's surface.

Improvement, the Performance of Polyurethane (PUR), Y-290 Resin as Coating of Oil Pipeline by Using Multi-Walled Carbon Nanotubes (MWCNTs)

In this study, polyurethane epoxy-Y290 (PUR-Y290) as a matrix material was reinforced by 1%MWCNTs. Polyurethane is a thermoset polymer and using for several applications particularly as coatings of gas and oil pipeline. Polyurethane uses as a liquid coating against the corrosion, and that is caused by the direct exposure for long periods of UV irradiation and humidity. The nanocomposites were prepared by adding 1wt% MWCNTs to polyurethane and mixed by using an ultrasound mixer. Polyueethane-1%MWCNTs composite sample was exposed to accelerate weathering (UV irradiation coming from sunlight, moisture, and salt water spray) during the exposure to different durations 6 months, 12 months and 24 months. Exposed and unexposed samples were investigated and evaluated by thermal and mechanical tests.It was found that the incorporation 1.0%wt of MWCNTs filler, enhanced the thermal stability and improved the mechanical properties during the exposure for long-term life to accelerated weathering conditions, compared with polyurethane coating without MWCNTs filler. These results indicated that polyurethane (liquid coating) nanocomposites have a higher resistance to environmental condition and give more protective against corrosion of oil pipelines and applied as coatings by spray method to protect the oil pipeline surfaces from environmental conditions.

Design of an oil pipeline nondestructive examination system based on ultrasonic testing and magnetic flux leakage

we analyzed the limitations of in-service oil pipeline ultrasonic inspection systems, and devised a scheme of an oil pipeline corrosion inspection system based on several ultrasonic sensors and magnetic flux leakage (MFL) sensors. On this basis, a ultrasonic/MFL pipeline corrosion testing system was successfully proposed in this paper, for which the multi-sensor information integration technology was used for data processing. Corresponding validation test results show that this system has improved the precision and accuracy of oil pipeline damage inspection and is of great pragmatic value in industrial engineering work.

A numerical study on water wetting associated with the internal corrosion of oil pipelines

Long distance pipelines are considered as the vein of the oil and gas industry on land and offshore. A well often produces water along with crude oil. The presence of water as well as dissolved gases such as CO2 and H2S introduces a serious menace of internal corrosion. It is well known that the distribution of water and oil inside the pipeline has a great influence on the corrosion rate. As a matter of fact, internal corrosion occurs when a free layer of water comes in contact with the pipe. Hence, predicting the distribution of water inside the pipe and identifying the continuous phase that directly wet the wall is of foremost importance when dealing with internal corrosion of oil pipelines. The accurate prediction of the distribution of water significantly increases the accuracy of corrosion prediction as well as the confidence regarding the integrity of the pipelines. In spite of all the great efforts toward studying different influential factors associated with the internal corrosion of steel pipelines, a large gap of knowledge is observed in predicting the water wetting. The objective of the present study is to employ a tuned two-fluid model by taking advantage of computational fluid dynamics, that is capable of predicting the distribution of water and the type of wetting (water wetting/oil wetting) at the bottom of the pipe. Furthermore, the effect of different parameters such as pipe diameter, oil density, oil viscosity and interfacial tension on the transition from water wetting to oil wetting is studied.

Electrochemical polarization study on crude oil pipeline corrosion by the produced water with high salinity

The effects of chloride ion, temperature, pH value, CO2 and O2 on the corrosion induced leakage of the inner wall of crude oil pipeline with the produced water were investigated by electrochemical polarization. The results showed that chloride ion corrosion would gradually experience the smooth invariant stage, the slow rise stage, and the rapid rise stage which due to the chloride ion destroy the corrosion product film. The corrosion rate would reach a maximum when the temperature was 65°C or the pH value was 3.5. O2 was the dominant factor induced the increase of corrosion rate when compared with the effect of CO2. Moreover, long term and periodic (30 consecutive days) electrochemical CO2 corrosion tests suggested that the CO2 corrosion rate reached a maximum at 4days. The obtained results would facilitate the formulation of control measures for pipeline corrosion in the oil field.

Optimization of Operating Conditions Affecting Microbiologically Influenced Corrosion of Mild Steel Exposed to Crude Oil Environments Using Response Surface Methodology

In this study, the influence of four operating parameters (pH, salinity, nitrate concentration and immersion time) and their interactions on the microbiologically influenced corrosion (MIC) rate of mild steel in simulated crude oil environments were investigated by response surface methodology (RSM). 4-level historical data design: pH (A) at 4, 6, 8, 10, salinity (B) at 25, 50, 75 and 100 g/l, nitrate (C) at 25, 50, 75 and 100 g/l and immersion time (D) at 168, 336, 504 and 672 h, was employed to correlate the factors with the corrosion rate as response. A polynomial regression model was developed and validated prior to optimization studies. The result showed that pH has the most influential effect on the response and that the predicted data had a reasonable agreement Original Research Article Salam et al.; BBJ, 7(2): 68-78, 2015; Article no.BBJ.2015.047 69 with the experimental data with the values of R = 0.9660 and Adj-R = 0.9516. The optimum conditions of the crude oil environments were observed at: pH (9.37), salinity (94.73 g/l), nitrate concentration (37.97 g/l) and immersion time of mild steel (168 h) in order to achieve minimum corrosion rate of 0.155196 mpy. The study has revealed that the historical data RSM design is an efficient statistical technique for predicting the optimum operating conditions of crude oil environments required to minimize mild steel corrosion in oil pipelines by incorporating all factors under consideration.

Effects of different concentrations of biocides on biofilm microorganisms in oil pipelines in Irri, Delta State, Nigeria

Biofilm can be defined as microbial communities containing large different numbers of microorganisms, which produce a wide range of biopolymers. This leads to adhesion to surfaces within hours of immersion. The attachment results in pit corrosion of oil pipelines. The study to assess the effect of different concentrations of biocides (0, 1,2,3,4 and 5 per cent) on bacterial diversity associated with corrosive biofilms in steel pipelines in Irri, Delta State was conducted in University of Calabar, Nigeria. Microbial communities associated with biofilms promote corrosion of oil and gas pipelines, which is a major problem confronting these industries. The community structure of bacteria in the biofilm formed in oil pipelines is a basic knowledge to understand the complexity and mechanisms of metal corrosion. To assess bacterial diversity, biofilm samples were obtained from mild steel coupons corroded after 127 days of exposure to normal operation and flow of petroleum. Microbial community analysis in biofilms of oil pipeline was determined by traditional cultivation technique. Most of the bacterial species detected in biofilms of oil pipelines included the following Halomonas subglaciescola, Pseudomonas aeruginosa, Klebsiella oxytoca, Bacillus subtilis, Serratia marcescens, Bacillus cereus, Acidithiobacillus ferrooxidans and Staphylococcus epidermidis. The sensitivity test results showed that Ozone (oxidizing biocide) exhibited the best biocidal characteristics and at the concentration of 1 percent, eliminated most of the bacterial species except the Gram positive and spore formers. The next effective biocide was sodium hypochlorite (oxidizing biocide) and then followed by formaldehyde as the least effective biocide. For effective control of biofilm bacteria, Ozone (oxidising biocide) and formaldehyde (non-oxidising biocide and persistent) should be used simultaneously as these biocides are effective against biofilms, bacteria and other microbes and are also environmental friendly biocides. The elimination or inhibition of these organisms in oil pipelines will keep our agricultural lands free of contamination from oil spills cause by corrosion.

Study on Pulsed Eddy Current Nondestructive Testing Technology for Pipeline Corrosion Defects Based on Finite Element Method

According to the principle and the type of the oil pipeline corrosion, we use the square wave of wide spectrum, strong signal transmission capability and a certain duty ratio as the excitation source of the pulsed eddy current. The finite element analysis software ANSYS is used to establish a three-dimensional finite element model of the pipeline corrosion defects by applying the boundary conditions of square wave excitation to simulate the distributions of current and induced magnetic field in the pipeline under various defect volumes. It can solve the induced voltage variation with time on detection coil, and can accomplish the finite element analysis and the nondestructive testing about the pipeline internal corrosion defects with the insulation layer and the protection layer. The results of the study show: When there is no corrosion defect in the pipeline, the electric current in the pipeline is basically even distribution. The magnetic field is distributed for the symmetrical vortex shape from head to foot, and it has not obviously gather phenomenon. When there are some corrosion defects in the pipeline, the electric current forms partial symmetrical vortex shape in both sides of the corrosion defect, and it is obviously assembled in the defect place. The simulation results of the different size defects show that the maximum magnetic field strength and the maximum current value increase with the defect depth increasing, while the output voltage decreases with the defect depth increasing. By extracting the induced voltage signals on the detection coil in a certain excitation condition, the quantitative detection of the pipeline corrosion defects can be achieved.

Efficacy of natural biocide on control of microbial induced corrosion in oil pipelines mediated by Desulfovibrio vulgaris and Desulfovibrio gigas

We compared the efficacy of a natural biocide with four chemical tetrakishydroxymethyl phosphonium sulfonate, benzyl trimethyl ammonium chloride, and formaldehyde, glutaraldehyde, to control microbial induced corrosion in oil pipelines. The efficacy of biocides were monitored against Desulfovibrio vulgaris and Desulfovibrio gigas in experimental pipes by measuring cell counts, H 2S production, Fe(II) production, production of extracellular polymeric substances and structure of biofilm. The treatment with cow urine had minimum planktonic cell counts of 3 × 10 2 CFU/mL as well as biofilm cell counts of 9 × 10 1 CFU/mL as compared with tetraki shy droxy 1 methyl phosphonium sulfonate, benzyl trimethyl ammonium chloride, formaldehyde and glutaraldehyde. Sulfide production was the lowest with cow urine (0.08 mmol/L), followed by tetraki shy droxy methyl phosphonium sulfonate 0.72 mmol/L. On day 90 of treatment, Fe(II) production was also found to be the lowest with cow urine. The scanning electron microscopic studies indicated that the biofilm bacteria were killed by cow urine. These results demonstrate the cow urine mediated control of microbially induced corrosion, and this is indicative of its potential as a viable substitute of toxic biocides. To the best of our knowledge, this seems to be the first report which screens possible biocidal activity by cow urine as compared to the most common biocides which oil industry is currently using.

Effect of chemical composition and structure on the resistance of oil pipelines to carbon dioxide corrosion

The mechanism of the influence of alloying of pipe steels with chromium and molybdenum on the development of carbon dioxide corrosion in oil pipelines is described. Corrosion products considerably enriched with alloying elements hinder contact between the metal and the corrosive medium.

Ultrasonic pig for submarine oil pipeline corrosion inspection

This paper introduces the design and development of an ultrasonic pig used for submarine oil pipeline corrosion inspection. Structure and functions of the equipment, as well as ultrasonic data acquisition system and off-line signal processing method are presented. The pig adopts a train-like structure including driver cups, batteries, ultrasonic transducers and data acquisition unit, which can detect and locate the corrosion of inspected pipeline. The data acquisition system is designed based on a digital signal processor and field programmable gate arrays structure to sample, process and compress the ultrasonic data and then store them in a hard disk. The off-line signal analysis method adopts a non-phase delay peak extraction algorithm to accurately calculate the pipe wall thickness. According to the thickness of each detected point, an ultrasonic image is traced by false color image, and then the potential defects are recognized by using a 3 × 3 grids template and classified according to American Petroleum Institute Standard. Both experimental and engineering testing results show that the pig is of perfect performance and could inspect defects greater than 10 × 10 mm2 successfully.

Technical Note:Rapid Detection and Quantification of Microbes Related to Microbiologically Influenced Corrosion Using Quantitative Polymerase Chain Reaction

Abstract Quantitative polymerase chain reaction (qPCR) assays were developed to detect and quantify bacteria and some critical sub-populations related to gas and oil pipeline corrosion. The 16S rRN...

Characterization of bacterial community associated to biofilms of corroded oil pipelines from the southeast of Mexico

Microbial communities associated to biofilms promote corrosion of oil pipelines. The community structure of bacteria in the biofilm formed in oil pipelines is the basic knowledge to understand the complexity and mechanisms of metal corrosion. To assess bacterial diversity, biofilm samples were obtained from X52 steel coupons corroded after 40 days of exposure to normal operation and flow conditions. The biofilm samples were directly used to extract metagenomic DNA, which was used as template to amplify 16S ribosomal gene by PCR. The PCR products of 16S ribosomal gene were also employed as template for sulfate-reducing bacteria (SRB) specific nested-PCR and both PCR products were utilized for the construction of gene libraries. The V3 region of the 16S rRNA gene was also amplified to analyse the bacterial diversity by analysis of denaturing gradient gel electrophoresis (DGGE). Ribosomal library and DGGE profiles exhibited limited bacterial diversity, basically including Citrobacter spp., Enterobacter spp. and Halanaerobium spp. while Desulfovibrio alaskensis and a novel clade within the genus Desulfonatronovibrio were detected from the nested PCR library. The biofilm samples were also taken for the isolation of SRB. Desulfovibrio alaskensis and Desulfovibrio capillatus, as well as some strains related to Citrobacter were isolated. SRB consists in a very small proportion of the community and Desulfovibrio spp. were the relatively abundant groups among the SRB. This is the first study directly exploring bacterial diversity in corrosive biofilms associated to steel pipelines subjected to normal operation conditions.

Chemical, Hydrodynamic, and Metallurgical Factors in West Siberian Oil Pipeline Corrosion Failure

Chemical, Hydrodynamic, and Metallurgical Factors in West Siberian Oil Pipeline Corrosion Failure

Structure of putrebactin, a new dihydroxamate siderophore produced by Shewanella putrefaciens

Shewanella putrefaciens is a bacterium implicated in oil pipeline corrosion and fish spoilage, and is one of very few isolated microorganisms able to use iron(III) as an electron acceptor. S. putrefaciens strain 200 produced a novel cyclic dihydroxamate siderophore, putrebactin, during aerobic growth. Putrebactin was determined to be 1,11-dihydroxy-1,6,11,16-tetraazacycloeicosane-2,5,12,15-tetrone, a cyclic dimer of succinyl-(N-hydroxyputrescine), by 1H and 13C NMR spectroscopy, fast atom bombardment and chemical ionization mass spectrometry, and X-ray crystallography. The protonation constants of putrebactin were determined to be 8.82 and 9.71. Potentiometric titration of the ferric complex revealed a sharp equivalence point at 3.0 equivalents of base per mole of Fe(III), consistent with loss of 3 protons per equivalent of bound ferric ion, while Job's method of continuous variation supported a shift from 1 : 1 to 3 : 2 complex stoichiometry as a function of pH. Putrebactin is similar in structure to two other siderophores, bisucaberin and alcaligin, produced by unrelated bacteria.