Search Results (4)

Glass Fibre Reinforced Polymer (GRFP) composites are increasingly being used as new materials for civil and petrochemical engineering infrastructures, owing to the combination of relatively high specific strength and stiffness and cost-competitiveness over traditional materials. However, practical concerns remain on the environmental stability of these materials in harsh environments. For instance, diffusion of salty water through the composites can trigger degradation and ageing. For this reason, a continuous monitoring of the integrity of GFRP composites is required. GRFPs health monitoring solutions, being non-destructive, in-situ, real-time, highly reliable and remotely controllable, are as desirable as challenging. Herein we develop and compare two methods for real-time monitoring of GRFP: one based on the electrical sensing signals of percolated carbon nanotubes (CNTs) networks and the other on optical fibre sensors (OFSs). As a proof-of-concept of dual sensory system, both sensors were used in combination to detect the diffusion of water through the composite. Measurements demonstrated that both CNTs and OFSs were able to detect water diffusion through the epoxy matrix successfully, with an on-off sensing behaviour. OFSs exhibit some advantages since they do not require electrical supply as required in hazardous environments and are more suitable for remote operation, which make them attractive for new developments in harsh-environment sensing. On the other hand, CNTs can be easily embedded in the composite without compromising its performance (e.g., mechanical properties) and are easily interrogated by measurement of electrical conductance, therefore could be used as spot sensors in the most failure-prone sections of GFRP components. This study opens up the possibility for an early detection of composites degradation, which could prevent failures in GFRP structures such as pipelines and storage tanks used in the oil and gas industry. Full article

Corrosion has been a great concern in the oil and natural gas industry costing billions of dollars annually in the U.S. The ability to monitor corrosion online before structural integrity is compromised can have a significant impact on preventing catastrophic events resulting from corrosion. This article critically reviews conventional corrosion sensors and emerging sensor technologies in terms of sensing principles, sensor designs, advantages, and limitations. Conventional corrosion sensors encompass corrosion coupons, electrical resistance probes, electrochemical sensors, ultrasonic testing sensors, magnetic flux leakage sensors, electromagnetic sensors, and in-line inspection tools. Emerging sensor technologies highlight optical fiber sensors (point, quasi-distributed, distributed) and passive wireless sensors such as passive radio-frequency identification sensors and surface acoustic wave sensors. Emerging sensors show great potential in continuous real-time in-situ monitoring of oil and natural gas infrastructure. Distributed chemical sensing is emphasized based on recent studies as a promising method to detect early corrosion onset and monitor corrosive environments for corrosion mitigation management. Additionally, challenges are discussed including durability and stability in extreme and harsh conditions such as high temperature high pressure in subsurface wellbores. Full article

A fiber optic interferometric sensor with an intrinsic transducer along a length of the fiber is presented for ultrasound measurements of the acoustic emission from partial discharges inside oil-filled power apparatus. The sensor is designed for high sensitivity measurements in a harsh electromagnetic field environment, with wide temperature changes and immersion in oil. It allows enough sensitivity for the application, for which the acoustic pressure is in the range of units of Pa at a frequency of 150 kHz. In addition, the accessibility to the sensing region is guaranteed by immune fiber-optic cables and the optical phase sensor output. The sensor design is a compact and rugged coil of fiber. In addition to a complete calibration, the in-situ results show that two types of partial discharges are measured through their acoustic emissions with the sensor immersed in oil. Full article

Absorption and fluorescence properties of 4 hydraulic oils (3 biological and 1petroleum-based) were investigated. In-situ LIF (laser-induced fluorescence) analysis of theoils on a brown sandy loam soil was performed. With calibration, quantitative detection wasachieved. Estimated limits of detection were below ca. 500 mg/kg for the petroleum-basedoil and ca. 2000 mg/kg for one biological oil. A semi-quantitative classification scheme isproposed for monitoring of the biological oils. This approach was applied to investigate themigration of a biological oil in soil-containing compartments, namely a soil column and asoil bed. Full article