Influence of Environmental Parameters on Microbiologically Influenced Corrosion Subject to Different Bacteria Strains (original) (raw)
Related papers
Bio-corrosion of carbon steel by sulfate reducing bacteria consortium in oil and gas pipelines
JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES
This research is aimed to give an overview of the impact of bio-corrosion on carbon steel grade API 5L X-70 immersed in growth medium and exposed to SRB consortium. Simulation of anaerobic corrosion conditions was carried out in a laboratory for 28 days. Raw crude oil gathered from the Baram Delta Operation Terminal was cultured in broth number 1249 (Modified Barr's Medium) to study the effect of bacteria growth upon metal loss. Carbon steel coupons grade X70 were cut to approximately 10mm x 20mm x 5mm and immersed in the cultured broth. During the experiment, the planktonic SRB were enumerated using a counting chamber (direct cell count method) under the electronic microscope at 200x magnification. Results indicated that the optimum pH and temperature for the respected SRB consortium genes were 8.5 and 37 °C, respectively. Metal loss of the corrosion specimen was measured and recorded after retrieval from the immersion period in the medium on a weekly basis prior to SRB inoculation for further analysis. The metal loss values supported that SRB activity can increase the metal loss of carbon steel against time of exposure. Additionally, the FESEM image showed the biofilm formations on the corrosion specimen. Thus, the results could conclude that biocorrosion caused by particular local SRB consortium can be considered as a threat to carbon steel pipelines. Besides, the effect of SRB activity and response towards metallic materials in a dynamic environment is an interesting topic to be studied upon in the future.
Mechanisms of Microbiologically Influenced Corrosion: A Review
2012
The main problem of biogenic is the production of H S in the oil industry that can lead to corrosion 2 and reservoir souring. Collection of bacteria called sulfate-reducing bacteria (SRB) is always the responsible of problems such as reservoir souring, equipment and pipeline failures. The corrosion mechanism understanding of SRB is unavoidable. In this study, various mechanisms proposed for SRB induced corrosion are investigated.
Journal of Chemistry, 2014
Various cases of accidents involving microbiology influenced corrosion (MIC) were reported by the oil and gas industry. Sulfate reducing bacteria (SRB) have always been linked to MIC mechanisms as one of the major causes of localized corrosion problems. In this study, SRB colonies were isolated from the soil in suspected areas near the natural gas transmission pipeline in Malaysia. The effects of ATCC 7757 and consortium of isolated SRB upon corrosion on API 5L X-70 carbon steel coupon were investigated using a weight loss method, an open circuit potential method (OCP), and a potentiodynamic polarization curves method in anaerobic conditions. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) were then used to determine the corrosion morphology in verifying the SRB activity and corrosion products formation. Results from the study show that the corrosion rate (CR) of weight loss method for the isolated SRB is recorded as 0.2017 mm/yr compared to 0.2530 ...
MICROBIOLOGICALLY INFLUENCED CORROSION OF MILD STEEL IN
In this study, the roles of microorganisms on the corrosion of mild steel in various simulated crude oil environments have been investigated experimentally under three (3) operating conditions namely: pH, salinity and nitrate. Since the presence of water supports microbial life, physicochemical properties and Total Microbial Count (TMC)) of the formation water was determined before adding it to crude oil. Corrosion analyses were performed by weight loss technique, microstructure examination and Fourier Transform Infrared Spectroscopy (FTIR). Microbiological analyses by isolation and identification using appearance factors were conducted on the biofilms formed. The result of physicochemical and biological characterization show that the levels of measured parameters favour the promotion of microbiologically influenced corrosion (MIC). The corrosion rates showed that high acidity (pH < 6) and high alkalinity (pH > 8) favours the growth and activities of microorganisms while increase in salinity and nitrate concentration of crude oil media hinders the growth and activities of microorganisms in the corrosion of mild steel. Microstructure examination depicted more severe pitting corrosion of mild steel in crude oil environment dominant in acidity than salinity and nitrate concentration. FTIR mainly revealed absorption band of –OH, COOH and NH2 indicating the presence of extracellular polymeric substances (EPS). Seven isolates of bacteria, predominantly negative gram strain (Gram-negative), were observed. In all, this study provides valuable insight into the MIC of mild steel by bacteria in crude oil environments.
Engineering Failure Analysis, 2020
This paper presents the long-term effect of sulfate-reducing bacteria (SRB) on the corrosion of buried cast iron pipes in soil and culture medium which has no previous research in literature. The comprehensive experimental design for investigating the external corrosion of buried pipes in soil and culture medium is developed in the current research. Coated specimens except their one side simulating the exterior surface of buried pipes are exposed to the SRB for 365 days in both the media. From the test results of corrosion rates and maximum pit depth, significant microbiologically influenced corrosion (MIC) of cast iron in the soil is observed as compared to the culture medium. The test results suggest that the testing of specimens in simulated soil solutions or culture medium instead of natural soil may lead to underestimated corrosion measurements for the buried pipe. The findings of this paper have practical applications for the prediction of failure of buried cast iron pipelines.
Microbiologically Influenced Corrosion (MIC)
Engineering Materials and Processes, 2008
s0010 8.1 Introduction p0010 Microbiologically influenced corrosion (MIC) has received increasing attention by engineers and scientists from different fields (materials and corrosion scientists and engineers, biologists, and microbiologists). MIC refers to the possibility that microorganisms are involved in the deterioration of metallic (and nonmetallic) materials. Microbial corrosion is a significant problem affecting the oil and gas and other industries. It degrades the integrity, safety, and reliability of pipeline operations and other systems. However, the mere presence of given classes of microbes associated with MIC does not indicate that MIC is occurring. Nor does showing that the presence of a given type of microorganisms establishes a cause-and-effect relationship between the bacteria and metal dissolution. For MIC to occur, water presence, even at very low amounts, is necessary [1e4]. p0015 The last decade revealed that not only the sulfate-reducing bacteria (SRB) are responsible for MIC but also several other microbes, e.g., the acid producers, iron oxidizers, and general aerobic bacteria [1]. MIC is rarely associated with one single mechanism or one single species of microorganisms. In addition to SRB many microorganisms occurring in natural environments are also considered corrosion-causing microbes, including methanogens, sulfur-oxidizing bacteria (SOB), acid-producing bacteria (APB), ironoxidizing bacteria (IOB), iron-reducing bacteria (IRB), and manganese-oxidizing bacteria (MOB). Each of these physiological groups of microorganisms may contain hundreds of individual species. Each group of bacteria or an individual species of bacteria alone can influence metal corrosion; however, severe MIC in a natural environment is always caused by microbial communities containing many different types of microbes. p0020 For better understanding of MIC and its threats on pipelines and other structures, it is essential to learn more about how microbes influence metallic corrosion, to identify their presence and existence, and to monitor their destructive activities. MIC is not a new type of corrosion, but it involves microorganisms that, by their presence and active, aggressive metabolites and exopolymeric substances (EPS) (produced by microorganisms and composed mainly of polysaccharides) degrade materials, especially metals. The metabolic products (e.g., sulfide, organic acids) alter the interface chemistry resulting in increased corrosion rate and, together with the EPS, on the metal surface cause pH and dissolved oxygen gradients that lead first to localized (pitting and crevice) corrosion, which if remains unmitigated, will lead to metal wall perforations [4e6].
Corrosion of x-70 carbon steel pipeline subject to sulfate reducing bacteria
ARPN journal of engineering and applied sciences, 2016
Carbon steels are commonly used as structural materials of piping systems in oil and gas industry because of their lower cost and wider availability despite their relatively lower corrosion resistance. This work investigates the preferable growth media for Sulfate Reducing Bacteria to proliferate rapidly and the effect of Microbiologically Influenced Corrosion activity towards carbon steel API 5L X-70 line pipe. Present research work highlighted that the preferred growth medium for ATCC 7757 and BARAM is Modified Baar's and Postgate C for Sg. Ular types of SRB. In addition, the corrosion rate was calculated using data based on metal weight loss experiment. The result confirmed that the corrosion rate in biotic (presence of Sulfate Reducing Bacteria) environment is much higher compared to abiotic environment (absence of Sulfate Reducing Bacteria). The pitting morphology that developed with time due to SRB activity was characterized with Field Emission Scanning Electron Microscopy...
Corrosion of carbon steels under anaerobic conditions in the presence of the sulfate-reducing bacteria (SRB) D. capillatus (DSM14982 T ) isolated from an oil field separator located in Tabasco, near of the Gulf of Mexico, has been studied. Immersion tests with two steels alloys, St-35.8 and API-5XL52 were performed. Total exposure was 45 days and different concentrations of electron acceptor were performed. Microscopic observations by scanning electron microscopy (SEM) and loss of weight measured as gcm -2 , indicated that the bacteria influenced behaviour of both materials.
A New Risk Assessment for Microbiologically Influenced Corrosion of Metals
1. Summary This project will use a new risk assessment method for the microbiologically influenced corrosion (MIC) of metals. This methodology improves upon existing mechanistic corrosion models by using the Friday 13 th (Fri13) deterministic framework, which is used to quantify the random fluctuations within a process by using Monte Carlo simulations. It is anticipated the statistical distributions of the simulations will then allow quantitative analysis of which process variables influencing MIC can be adjusted to reduce the occurrence of MIC inducing an equipment failure. MIC is a pervasive form of corrosion present in many chemical-processing industries. MIC develops rapidly and can significantly decrease equipment lifespan and cause unexpected failures from pitting corrosion on metal pipe surfaces. Additionally, a further effect from MIC pitting is increasing the friction factor inside pipes that can reduce flow capacity and ability for heat transfer on the pipe surface in heat exchangers. No industry guidelines currently exist for quantifying what is an acceptable level of MIC in a given environment, or how it should be dealt with. Existing corrosion models are limited in their accuracy for conducting quantitative risk assessment because they cannot incorporate the natural fluctuations that occurs within the many biological parameters associated with MIC. This limitation is mitigated by using the Fri13 deterministic framework that quantifies process fluctuations as a distribution, allowing a comprehensive risk assessment methodology to be developed that can more accurately address the risks posed by MIC in steady-state processing for fluctuating pH and corrosion conditions. 2. Key Words Microbiologically Influenced Corrosion, corrosion model, risk assessment, Friday 13th 3. Background MIC occurs from the presence of microorganisms within liquid called chemoautotrophs that survive from electron donors in their environment, which the metal materials used to transport fluids are a prime source for. Thus MIC is driven by microorganisms inducing an electrochemical process to obtain energy and is a different form of corrosion compared to galvanic corrosion, which is also an electrochemical process but not influenced by microorganisms. Commonly found in industrial environments such as water treatment, fuel and oil pipelines, the two most prevalent groups of corrosion inducing bacteria are Sulfate Reducing Bacteria (SRB) and Acid Producing Bacteria (APB), which are capable of developing and surviving across an extreme range of pH and temperature, aerobic and anaerobic conditions. SRB was the earliest recognised form of microorganism responsible for MIC in the 1930s and is an extremely widespread bacteria group due to it relationship with the sulfur cycle. SRB obtains energy from organic compounds by reducing sulfate (SO 4 2-) to hydrogen sulfide (H 2 S), where the latter compound additionally assists in contributing to corrosion. APB is another major group of microorganisms that contribute to MIC through producing organic and inorganic acids that result in acid corrosion along with establishing prime conditions for SRB growth. Historically studies have been focused almost exclusively on SRB, however more recent work, such by Gu (2014), has determined APB can induce MIC quicker then SRB in certain conditions.