CUI Management Through Moisture Barrier System and Field Assessment
authors: Ahmad Raza Khan Rana, Graham Brigham, Andrew Buchanan
This article presents a case study of moisture management where a hydrocarbon operator faced the challenge of frequent soaking of thermal insulation that caused the operator to replace the entire insulation on a multi-kilometer pipeline twice within an operating period of 10 years. The newer insulation was installed with and without various combinations of moisture barrier devices. Assessments were made on a bi-weekly basis over a period of 7 months. The various combinations of moisture barrier devices significantly reduced the moisture content of the entire insulation system. This article also addresses the modular management via termination gaskets for the compartmentalization and assessment of trapped moisture within any insulation system. Read more...
Influence of Robust Drain Openings and Insulation Standoffs on Corrosion Under Insulation Behavior of Carbon Steel
authors: Ahmad Raza Khan Rana, Mingzhang Yang, Jamal Umer, Tom Veret, Graham Brigham
Corrosion under insulation (CUI) is among the key concerns for the integrity of process equipment and pipelines. Various measures to detect and fix the damages from CUI pose significant maintenance expenditures in hydrocarbons processing facilities. The key reason behind CUI is the limitation of thermal insulation to absorb the moisture and soak the underneath metal from wicking action. Other than CUI, trapped moisture in the soaked thermal insulations causes heat loss from process systems, thereby posing the risk of additional damage mechanisms and increased operating expenditures. This study addresses the impact of robust drain openings and insulation standoffs on the CUI rate of carbon steel under four different testing conditions, namely isothermal wet, isothermal wet-dry, cyclic wet, and cyclic wet-dry, respectively. Read more...
Moisture Drainage and Stand-Offs Impact on Insulation Wetting
authors: Ahmad Raza Khan Rana, Graham Brigham
In this study, insulated pipe assemblies with stand-offs and low-point drains were studied for drainage performance. Insulated pipes were soaked with measured aliquots of water followed by quantification of drained water. Patterns of moisture trapping underneath insulation were visualized using moisture detection imaging. A contact-free insulation system with low-point drains achieved maximum drainage efficiency (97%) and the least moisture trapping. Read more...
Corrosion Under Insulation Performance of Insulation Stand-Offs and Non-Metallic Membranes
authors: Ahmad Raza Khan Rana, Graham Brigham, Omar Chaar, George Jarjoura
CUI (Corrosion Under Insulation) is among the key damage mechanisms affecting equipment and piping in hydrocarbon processing facilities, as well as pipelines. The key reason behind CUI is the contact of soaked insulations with the metal(s). Insulation stand-offs and membranes can keep the soaked insulation off the pipe and mitigate CUI risk. This research study addresses the CUI simulation tests to characterize the corrosion behaviors of carbon steel under isothermal wet and cyclic wet conditions, in the presence of insulation stand-offs, low point drains, and Teflon membranes. The corroded coupons were characterized using microscope and surface topography Read more...
Localized Corrosion Management for Thermally Insulated Systems via Insulation Stand-offs and Low Point Drains
authors: Ahmad Raza Khan Rana, Graham Brigham, Omar Chaar, George Jarjoura
CUI (corrosion under insulation) is a major damage mechanism affecting the integrity of process equipment, piping, and pipelines. CUI is known to create localized corrosion and pitting under thermal insulations which trigger non-linear corrosion rates and end up in unanticipated leaks in industrial assets. Reportedly, detection and management of CUI-driven damages constitute 10% of the maintenance budget in a typical refinery. This study simulates the CUI behavior of carbon steel under fibrous stone wool insulation using four testing conditions namely Isothermal wet, isothermal wet-dry, cyclic wet, and cyclic wet-dry. The weight loss of coupons under each test condition was converted into corrosion rate Read More...
Corrosion Under Insulation Behavior of Phenolic Epoxy Coatings under Contacting and Contact-free Insulations
authors: Ahmad Raza Khan Rana, Graham Brigham, Omar Chaar, George Jarjoura
CUI (corrosion under insulation) is reportedly a contributor to the failure of insulated piping and process equipment. Protective coatings are among various effective measures to manage the CUI of industrial assets. Phenolic epoxy is among the widely used coatings under thermal insulations. This research work involves CUI testing of phenolic epoxy coating for 192 hours as per applicable ASTM standard G189-07 using cyclic wet operating conditions. The resulting weight loss from the test was converted to corrosion rate followed by microscopic Read More...
Moisture Management in Thermal Insulations for In-service and Out of Service Pipelines
authors: Ahmad Raza Khan Rana, Graham Brigham
CUI (Corrosion Under Insulation) is a key degradation in facilities and pipelines and known to drive 40% - 60% failures in the piping systems. CUI is known to trigger from the soaked insulations that are held in contact with the metal(s). Although high operating temperatures are perceived to reduce CUI risks, integrity issues happen due to condensation or sweating once the pipe/ equipment is brought through cyclic temperatures or transient conditions. With lower or even ambient temperatures, the content of liquid moisture within the insulation increases which ends up exploiting Read More...
A Hybrid Approach for Effective CUI Management
authors: Ahmad Raza Khan Rana, Graham Brigham
Corrosion under insulation (CUI) is a common damage mechanism in the hydrocarbon production and processing industries, typically manifesting as localized corrosion/pitting [1]. CUI is generally triggered by moisture-saturated thermal insulation, where the time of wetness (TOW), in addition to other factors (chemistry, design, temperature, etc.), govern the rate of CUI propagation [2-3]. In addition to CUI, moisture-soaked thermal insulation can cause heat dissipation from thermally insulated assets. It is estimated that moisture content as low as 5% within thermal insulation can increase heat loss by 25% in a typical Read More...