Corrosion under insulation (CUI) is a major problem for petroleum and petrochemical process industries that affects the plant mechanical integrity and attacks assets. CUI can result in sudden and hazardous leaks (safety concern), and plant shutdowns with high losses of production (economical concern).
Traditional detecting methods of CUI to cut a window in thermal insulation used to inspect visually, to measure the thickness, and then return thermal insulation back, giving high chance for water and moisture ingress, accelerating CUI, moreover big amount of scaffolding erection along with thermal insulation removal required.
SHARQ (Eastern Petrochemical Company, one of SABIC companies) is pioneer to study CUI, evaluating many Non–Destructive techniques has proven Pulsed Eddy Current (PEC) as the most effective technique in terms of integrity and cost optimization.
Considering all available techniques, all aspects studied, such as range of applications, features, and limitations, it is concluded and verified to meet our inspection plan strategy needs.
PEC does not require thermal insulation removal; optimize scaffolding erection, has a wide range of applications related to thickness, and temperature. PEC approved by international codes and standards (API) to meet RBI Meridium software requirements.
The validation study results show cost savings of more than 50% compared to traditional thickness measurement methodology, moreover it reduces EHSS (Environment, Health, Safety, and Security) negative impact reduces the probability of safety incidents due to reducing labor, man-hours, and eliminating many associated activities with potential hazard and risk.
PEC has high productivity, easily operated, and provides comprehensive and professional inspection report

In any operating facility, the integrity of flare or relief lines should always be closely maintained, as it is one of the most important safeguards during plant upsets or emergency conditions. The most common damage mechanism in acid flare lines is acid gas dew point corrosion”. Corrosion in such systems is often dependent on fluid stagnation, especially in the presence of acidic water, during idle conditions.
The intent of this paper is to shed light on the efforts done in a gas treatment facility to identify different root causes that impacted or accelerated Acid Gas Dew Point Corrosion. These included design deficiencies, equipment integrity, and process challenges. Moreover, the paper provides findings and recommendations to avoid the occurrence of similar events in acid flare lines.

Hydrocracking and other refinery hydroprocessing units have a common goal to convert organic sulfur compounds to hydrogen sulfide (H2S) that can be removed, thereby producing low-sulfur refinery products. Corrosion and equipment degradation risks range from high-temperature hydrogen attacks (HTHA) to ammonium bisulfide and ammonium chloride corrosion in the downstream heat recovery and fluid separation equipment.
This paper provides an overview of corrosion management principles that can be applied to reduce operating risks in new and existing units, focusing equipment susceptible to ammonium bisulfide (NH4HS) and ammonium chloride (NH4Cl) corrosion. Best practices for materials selection, as well as designing for corrosion management through adequate provision of corrosion management related instrumentation and sampling points are covered.