Colocation of a new transmission line with an existing pipeline right of way (ROW) can have many benefits including lower cost and quicker acquisition of easements. Public utility commissions and other government agencies may suggest or direct colocation with other utilities. However close alignment between transmission line and pipelines will result in inducing voltages and currents into the pipeline(s). These induced voltages and currents may have undesirable consequences for the pipeline inducing unsafe step and touch potentials damage to pipeline coatings and damage to the pipeline steel including AC corrosion. While there are many techniques available to mitigate these effects doing so may be very costly. Increasing separation distance between the utilities is generally more cost effective than providing very extensive mitigation. It is far better to assess these costs during the route selection process rather than to be committed to a preferred route than to discover that IAC mitigation will be very complex costly and will resulting delaying completion of the project. This paper presents a recent case history that fully illustrates the complexity time delays and cost associated with IAC mitigation for four large diameter natural gas lines from a newly constructed 220 kV wind farm transmission line after the preferred route has been selected and ROW had been purchased.

Permanent and temporarily installed ultrasonic sensors have been used in refineries for over 10 years. Advances in capability deployment and shrinking size and costs have lead many facilities to augment their routine thickness data collection means from a fully manual fleet of technicians to sensor based near real-time monitoring. The deployment of fully wireless long range ultrasonic sensors has been reduced in complexity and had a great effect on how operators and asset owners are managing their asset integrity programs. This paper will discuss industry examples and case studies of mapping their operational data to corrosion monitoring data. This in turn has paved the way for decision making on day-to-day in areas of inhibitor utilization hard to access inspection locations and asset retirement strategies. 

The aromatics plant is an important downstream petrochemical unit that produces various aromatic hydrocarbons such as xylenes benzene and toluene which are the basic building blocks for production of polyester and polymers resulting in different consumer goods. The heart of aromatics plant is a licensed high performance Naphtha Reforming unit that operates at low pressure and high temperatures required to promote chemical reactions that improve aromatics production.To achieve the required heat there are 4no. of fired heaters with vertical “inverted U” type coil configuration that raise the feed naphtha temperature to around 545 Deg C. The radiant tubes of the heaters are of 9Cr-1Mo (ASTM A335 Gr P9) metallurgy with a maximum tube wall temperature of 652° C. The tubes are prone to excessive scaling due to high temperature oxidation and scale thickness of upto 2mm was found in the tubes. The problem arising due to scaling affect not only the mechanical integrity of the radiant tubes but also lead to multiple operational constraints.From integrity point of view scale being part of metal it is consuming the metal at a rate of 0.25mm/year. This was evident from the UT survey carried out on the tubes which revealed a minimum thickness of 4.6mm as against original thickness of 6.02mm. Secondly oxide scale being an insulator restricts the heat transfer across the tube and thus preventing to raise process fluid temperatures to the required levels. As a consequence with burners at full load the unit had to be operated at lower capacity by reducing flowrate of the process fluid. Moreover due to severe scaling it was not viable to run the unit continuously without taking a shutdown every quarter to clean off the scales. This resulted in further production and financial loss.Following a detailed root cause analysis it was recommended to apply ceramic coating on the radiant tube and extend it to refractory in the furnace box to improve operational and thermal efficiency while maintainingmetallurgical reliability and stability.The ceramic coating was expected to result in severaloperational benefits by creating a uniform heatingprofile along with reducing the diffusion mechanism of oxidation eliminating insulative (scale and oxide)surface layers that form during high temperature operation. Post coating (applied in March 2017) the unit is capable to run at more than 100% at the same heater load and also assurance of long term integrity of the heater tubes. The payback from the investment was within 6 months of project execution.This case study highlights the observations of the radiant tubes along with the cost benefit analysis achieved by the application of ceramic coatings to extend tube life and improve operational efficiency.Keywords: Naphtha Reforming Ceramic Coating Radiant Tubes Oxidation