Integrity Challenges Associated with Stray Current Corrosion Across Monolithic IJ's and Resolutions

Corrosion and subsequent failures is one of the main factors affecting uninterrupted operations of Oil & Gas Industries. Pipelines are considered as most convenient means of crude and gas transportation in Oil & Gas Industry. Buried pipelines generally made of low carbon steel material are protected externally by coating and applying impressed current cathodic protection (ICCP). Monitoring and maintaining adequate level of Cathodic Protection (CP) for such pipelines remains challenging for corrosion engineers due to increased level of field congestion, complexity in accurate current mapping and mitigation of corrosion phenomena. Failure of pipelines due to corrosion can be catastrophic with following consequences: Loss of containment fluid and thereby probable fatalityDamage to asset/company reputationSafety and Environment (Fire, Toxic gases and Oil Spill)Resource and downtime cost impact Isolation joints IJ's are designed with very high insulating material at mating areas and installed on pipelines by welding to avoid loss of Cathodic Protection (CP) current. Due to high electrical insulation, a potential difference is formed across of IJ's due to applied CP current and stray currents. In upstream Oil & Gas Industry, multiphase crude transported via pipeline will have certain percentage of water and will induce an internal conductive path across the IJs resulting in ionic current discharge at anodic areas within internal surface. This study focuses on factors contributing to such internal stray current corrosion, limitation in monitoring methodology and mitigation programs. The study concludes with recommendations such as design modifications, improvement in internal lining properties and improved installation guidelines. The study practically illustrates effectiveness of combined resistive bonding and zinc earthing cells installation for controlling stray current propagation in order to reduce the corrosion rate so as to maintain Integrity of pipelines.

Compliance of fire-protective cellulose-containing materials with environmental safety

Search for new highly efficient agents for wood fire retardant treatment in the construction has been conducted more and more intensively. But fire retardant treatment nowadays should not only ensure specified fire resistance of wood but preserve its performance as well as ensure its environmental safety and durability. Therefore a significant problem of ensuring vital activities and safe functioning of building facilities lies in the development of intumescent coatings for building structures taking into consideration economical, processing and environmental aspects; these coatings shall be used not only on a par with existing similar ones but be highly efficient in special spheres of construction which makes it possible to prevent occurrence of man-caused accidents. The paper shows results of the studies purposed at raising efficiency of the facilities protection by conversion of the cellulose containing materials used at them to the group of hardly combustible materials; it was revealed that application of appropriate composition converted the wood into hardly combustible material that did not spread flame across its surface and had moderate smoke production ability. Taking into account these fire hazard indices the wood having been subjected to fire retardant treatment as construction material could be allowed for application for the internal lining of rooms including those at the escape routes.

Prelaminated paramedian forehead flap for subtotal nasal reconstruction using three-dimensional printing

Nasal reconstruction following a total or subtotal resection presents a challenging clinical scenario. Ample external skin coverage is readily available using the paramedian forehead flap (PMFF), but restoring adequate internal lining of sufficient size and pliability is a major limitation. Intranasal mucosal flaps or free tissue transfer is often employed for this purpose, each with their own sets of limitations. Prelamination of the PMFF with a skin graft prior to transfer is a method to create a composite flap with both internal and external lining. Another challenge in subtotal nasal reconstruction centres around restoring adequate dimensions to the nose without an existing template to work from. Three-dimensional (3D) printing has become an increasingly popular tool in reconstructive surgery as it captures precise patient-specific dimensions to guide reconstruction. Herein, we describe a case of subtotal nasal reconstruction using a prelaminated PMFF using a patient-specific 3D printed model as a template for reconstruction.

Active Cardboard Box with Smart Internal Lining Based on Encapsulated Essential Oils for Enhancing the Shelf Life of Fresh Mandarins

Mandarins are usually sold in bulk and refrigerated in open cardboard boxes with a relatively short shelf-life (12–15 days) due to physiological and pathological disorders (rot, dehydration, internal breakdown, etc.). The influence of a controlled release of essential oils (EOs) from an active packaging (including β-cyclodextrin-EOs inclusion complex) was studied on the mandarin quality stability, comparing different sized cardboard trays and boxes, either non-active or active, at the pilot plant scale (experiment 1; commercialization simulation at room temperature after a previous simulation of short transportation/storage of 5 days at 8 °C). Then, the selected package was further validated at the industrial scale (experiment 2; cold storage at 8 °C up to 21 days). Among package types, the active large box (≈10 kg fruit per box) better maintained the mandarin quality, extending the shelf life from two weeks (non-active large box) to three weeks at room temperature. Particularly, the active large box highly controlled microbial growth (up to two log units), reduced weight losses (by 1.6-fold), reduced acidity, and increased soluble solids (highly appreciated in sensory analyses), while it minimized colour and controlled firmness changes after three weeks. Such trends were also observed during the validation experiment, extending the shelf life (based on sensory quality) from 14 to at least 21 days. In conclusion, the mandarin’s shelf life with this active cardboard box format was extended more than one week at 8 °C.

Integrity Assessment of Internally Corroded Pipelines Rehabilitated With a Kevlar-Reinforced Flexible Liner

Contemporary approach of corrosion prevention is to use internal lining system to isolate the corrosive medium from the host pipe's inner surface. The liners serve to offer a longer lifecycle of pipelines, as well as a corrosion barrier against aggressive chemical agents. A recent lining technology based on a Kevlar-reinforced flexible polymer composite liner called the InField Liner (IFL) has been successfully installed in several pipelines. It has been theorized that the added inherent strength of the liner due to the Kevlar-reinforcement can give rise to an increase in burst pressure level of the corroded pipeline. The mechanical response of the IFL liner is established accurately and used to define the constitutive behavior of the IFL material in a nonlinear finite element model of liner installed in a host pipe with internal corrosion defect. The results reveal that an increase in burst pressure is achieved with the IFL liner, which is attributed to the interaction between the IFL and the internal corrosion defect. The increase in burst pressure is especially noted for rather deep and short length defects. The primary reason to the increase is the stretch of the Kevlar fabric into the defect cavity inducing a load transfer between the liner and pipe at the defect zone. A closed-form solution is developed, which can be used to assess the increase in burst of pipelines containing internal corrosion defects when rehabilitated with an IFL liner. The results of the study demonstrate that the IFL internal lining technology can be used as a corrosion barrier in steel pipelines for rehabilitation of old pipelines, as well as providing an increase in burst pressure level when the liner is installed due to its complex interaction with the internal corrosion defect.

Burst Pressure Prediction of Pipes With Internal Corrosion Defects

Corrosion in pipeline walls can lead to severe loss of material to a point which will cause complete loss of pipeline integrity. The contemporary approach of corrosion prevention is to use internal lining system to isolate the corrosive medium from the inner surface of the host pipe. The objective of this study is to assess the burst pressure of pipelines with internal corrosion defects. The mechanical response of carbon steel API X42, X52, and X70 pipe grades are empirically estimated and implemented in a finite element model. The geometry of an internal corrosion defect is defined through its depth, width, and length, and a parametric study is undertaken to investigate the influence of the corrosion defect parameters to the overall burst pressure of the pipe. Based on the results from the parametric study, the Buckingham π-theorem is used to derive an analytical closed-form expression to predict the burst pressure of internally corroded pipes, which is found to agree markedly well with the experimental results.

Design and Execution of Turdas Tunnel

The paper presents aspects of the design and execution of the Turdas tunnel located on the local variant (route), on the Coşlariu - Simeria section, from the rehabilitation project of Brasov – Simeria railway line, component part of Pan European Railway Corridor IV, for train circulation with maximum speed of 160km/h. The tunnel crosses through alluvial deposits with silt and clay with locally sand layers at the upper part, sand and gravel with water in the middle part and marly silty clay and neogenic marl, with swelling phenomena, at the lower part. The overburden is between 2.00m and 13.00m. The initial project provided execution in underground, on 510.00m in the central area and from surface at both ends, 225.00m at the entrance and 45.00m at the exit. The new optimized project, based on new geological and geotechnical studies, proposed an execution from surface for the entire length of the tunnel. To establish the optimal solution two methods of surface execution and structural solutions were analyzed comparatively: “Cut and Cover” and “Cover and Cut”. The adopted method was “Cut and Cover”, with a structural solution composed of a temporary retaining structure – diaphragm walls with a special internal lining. This has been divided in six sections with different behavioral types, taking into account the ground configuration in longitudinal profile and the geological and geotechnical data. The technological execution phases are presented in detail. To investigate the behavior of this type of structure under soil and swelling actions, three-dimensional finite element analyses were carried out, taking into account the execution phases for each cross section. A monitoring system was provided to verify the stresses in the temporary retaining structure and the internal lining and also to calibrate future calculations.