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.

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

The heat treatment condition of industrial materials is a critical parameter for material evaluation and its fitness for intended service. Proper heat treatment will produce desired mechanical and physical properties, while absence or improper heat treatment may lead to major failure with huge production, Environmental, Health, and Safety (EHS) impacts. We hereby explain an actual case for cracked gas compressor (CGC) 5th stage discharge line caustic stress corrosion cracking (SCC) that caused unplanned plant shut down and resulted in noticed financial and production loss.
The proven root cause is absence of normalization. Emergency piping batch is received and supposed to be normalized to avoid failure recurrence. Many discrepancies extracted from submitted material certificates, also many physical signs observed on the material itself raising doubts about received material compatibility. Using advanced Positive Material Identification (PMI) device to verify the chemical composition of the received material, results show that the material is questionable.
As a precise test to verify heat treatment condition, microstructure analysis test (metallography) conducted to confirm normalization condition of the material, the resulted grain structure size and growth confirm that one of the received pipes has improper or absence of normalization.
The material rejected as it is proven and confirmed that it is not normalized as per the requirements to avoid further potential of hydrocarbon leakage due to improper material specification. Rejecting the material eliminate the potential of having repeated failure, in addition to 600,000 Saudi Riyal (SR) cost saving as material cost. A common recommendation shared with concerned parties to consider metallography as a mandatory test to be submitted with heat-treated material test certificate (MTC).
Key words: Heat treatment, microstructure, normalization, grain structure, failure, metallography