Understanding and addressing Microbiologically Influenced Corrosion (MIC)

Microbial life is everywhere. Microorganisms have been found inhabiting iced-covered lakes in Antarctica at -13°C and hydrothermal vents at the bottom of the ocean at 120°C [1]. Microorganisms have inhabited our planet for billions of years before plants and animals appeared. It was through their activities that higher forms of life could appear and thrive [2]. However, microorganisms can also be harmful and their activities can result, under certain conditions, in detrimental effects such as disease and damage to infrastructure. Industrial systems typically create new microbial habitats that can stimulate undesired microbial activities. A notable example of this is microbiologically influenced corrosion (MIC) which refers to corrosion of metallic equipment and structures caused or accelerated by microorganisms. These microorganisms are mainly bacteria and archaea, but microalgae and fungi can also be important contributors in certain environments [3, 4]. In Australia, MIC represents a common threat to the oil & gas, defence and marine industries which are major components of the national economy. Deterioration and corrosion due to microorganisms drives a worldwide market for microbial control that is worth billions of dollars annually

The role of bacteria in under-deposit corrosion in oil and gas facilities: A review of mechanisms, test methods and corrosion inhibition

Under deposit corrosion (UDC) has been identified as a phenomenon responsible for many operation failures, representing a threat to pipelines integrity and seawater injection systems. Despite the recent efforts to define the effects of deposits on corrosion of steel surfaces and their inhibition, the influence of microorganisms in these deposited environments have not been largely addressed. Understanding the effect of microbial activity on UDC is important because microbial cells thrive in deposits resulting in an adverse combination of microbiologically influenced corrosion (MIC) and UDC. Additionally, UDC mitigation constitutes a challenging topic since solid particles can decrease the availability of inhibitor molecules to protect the underlying steel against corrosion. Biofilms comprise a complex array of molecules and microorganisms that can act as organic deposits compromising the performance of corrosion inhibitors. Therefore, is important to evaluate the corrosion inhibitor efficiency in the presence of biofilm-deposits formed on steels surfaces. This document reviews the literature on UDC-MIC mechanisms, testing methods and prospects in the understanding and inhibition of these complex phenomena

Regional Trade and Logistics Infrastructure: A Spatial Approach

This paper aims to analyze whether the existing logistics platforms network in Spain affects Spanish transport demand by using a spatial framework. In particular, we use demand for transport to export goods to other Spanish provinces as a proxy for logistics infrastructure demand in Spain. Then, we obtain data for trade flows between provinces (NUTS3) in the year 2007. We also obtain data about the number and area of logistics platforms existing in each Spanish province to proxy for the transportation network structure in Spain. In a first step, we construct weight matrixes considering first-order contiguity and we obtain that spatial dependence is significant in a spatial econometric model of commodity flows (LeSage and Polasek, 2008). Secondly, we incorporate logistics network structure dependence into the model so that the spatial lags measure the impact and significance on trade flows from all origins to all destinations by considering the importance of logistics performance in the neighboring provinces. Finally, we perform the analysis for different economic activities. The results obtained provide evidence about the role of the location of logistics platforms for satisfying existing demand for transport structure in the Spanish provinces..

Microbiologically Influenced Corrosion in Floating Productions Systems

Microbiologically influenced corrosion (MIC) represents a serious and challenging problem in Floating, Production, Storage and Offloading vessels (FPSOs), one of the most common type of offshore oil production facilities in Australia. Microorganisms can attach to metal surfaces, which under certain conditions, can result in corrosion rates in excess of 10 mm per year (mmpy) leading to equipment failure before their expected lifetime. Particularly, increasing water cut (ratio of water vs. total fluids produced), normally resulting from the age of the assets, results in an increased risk of MIC. This paper provides an overview of causative microorganisms, their source of contamination and the areas within FPSOs that are most prone to MIC. Although mitigation practices such as chemical treatments, flushing and draining and even cathodic protection are effective, MIC can still occur if the systems are not properly monitored and managed. A case study is presented that describes the microorganisms identified in a FPSO operating in Australia suspected of having MIC issues

Tetra-substituted olefin synthesis using palladium-catalysed C-H activation

In an effort to obtain more efficient and greener chemical transformations, a substantial amount of research interest has been directed towards the use of arene C-H bonds as functional groups. Hydroarylation of alkynes through direct functionalisation of C-H bonds has been studied in recent years leading to the development of high-yielding metal-mediated processes. The main aim of the current work is the addition of a third component in the hydroarylation of alkynes trough C-H activation, in order to achieve a second C-C bond formation. Attempts at palladium-catalysed three-component reaction of unactivated indoles with alkynes and aryliodides are described. The three-component reaction was studied in the intermolecular mode with both aryliodides and the more reactive diaryliodonium salts. These latter regents are reactive arylating and oxidising agents and have been used in the direct arylation of indoles under mild conditions through a PdII-PdIV catalytic cycle. In both cases the three-component product was not obtained. The intramolecular version of the reaction using alkyne-tethered indoles and diaryliodonium salts is also described. In this case the tandem process was successful, especially when using ethynylbenzyl indole derivatives, the Z-tetrasubstituted olefins could be selectively obtained under mild conditions. Finally, a low-yielding synthesis of chromenes from propargylaryl ethers and diaryliodonium salts is also discussed

Effect of sample storage conditions on the molecular assessment of MIC

Microbiological surveys play a fundamental role in diagnosing and monitoring microbiologically influenced corrosion (MIC) in oil and gas production systems. Currently, microbiological characterization is being carried out by the implementation of molecular microbiological methods (MMMs) such as the 16S rRNA gene diversity profiling. Molecular characterization of microorganisms provides information to assess the risk of MIC in the production facilities. Even though MMMs have been included in NACE standards, standardized protocols for collection, storage and preservation of oilfield samples have not been written. In this study, the effect of sample storage conditions on the microbial composition, community structure, alpha diversity and functional capability of oilfield samples was investigated. The effect of storage samples at room temperature or refrigeration on the molecular MIC assessment was statistically evaluated by comparison with samples preprocessed and preserved on-site straight upon collection. Sample storage resulted in changes in the relative abundance of the microbial populations, which had a significant impact on the alpha diversity and structure of the community. Likewise, the functional capability of the microbial community in oilfield samples was affected by storage conditions. Abundances of genes associated with corrosive pathways such as sulphate reduction, iron utilization and methanogenesis decreased under conditions evaluated. Results of this research provide evidence of the importance of sample handling for an accurate microbial characterization and subsequent assessment of the MIC risk in industrial systems. Thereby, on-site pre-processing of the samples and addition of nucleic acids preservation solutions is recommended for an optimal microbiological survey, and in cases where this is not feasible, refrigeration is preferred over room temperature storage conditions