Low Temperature Corrosion

There is no fixed boundary for distinguishing between low- and high-temperature corrosion. Most commonly, it is assumed that low-temperature corrosion processes occur in the presence of liquid water at temperatures up to a maximum of about 200°C (392°F). However, some authors extend this upper limit to 260°C (500°F). For the purpose of this library, we excluded environmental cracking phenomena from the category of low-temperature corrosion. However, it’s important to note that many cracking damages require the presence of an electrolyte (such as water) and/or occur at temperatures below 200°C-260°C.
Amine Corrosion

The importance of Amine Unit is commonly underestimated, it is one of the most important units not only in refining operations but also Oil&Gas exploration and Petrochemical production. This chapter highlights some important aspects of corrosion caused by lean and rich amine solvents.

Ammonium Bisulfide Corrosion

The intensification of ammonium bisulfide corrosion is a ‘byproduct’ of processing crude slates with increasing concentrations of sulfur and nitrogen compounds. This chapter provides an overview of NH4HS corrosion problems, focusing on the impact of process parameters and material selection

Ammonium Chloride Corrosion

Ammonium chloride corrosion, alongside ammonium bisulfide corrosion and wet-H2S damage, constitutes the most prevalent group of low-temperature damage mechanisms in the refining industry. NH4Cl is recognized for its dual effect: fouling and, when the deposit becomes wet, fostering severe corrosion beneath it. Due to the nature of this under-deposit attack, accurately predicting the location and rate of degradation is challenging. The subsequent chapter offers an overview of the NH4Cl corrosion phenomenon, mitigation strategies, and guidelines for material selection.

Corrosion Under Insulation

Insulating pipelines and equipment is a standard practice for conserving energy in process units. It serves various functions, including fireproofing, ensuring personnel protection, heat tracing, and acoustic protection. Dry insulation is generally neutral to the corrosion of the protected metal surface; however, when wet, it can result in slow but inevitable metal degradation. After remaining undetected for decades, corrosion under insulation (CUI) may be unveiled through catastrophic failures.

Hydrochloric Acid Corrosion

An aqueous solution of hydrochloric acid (HCl or HClaq) stands out as one of the few compounds highly aggressive toward nearly all popular corrosion-resistant alloys (CRA). The following chapter covers significant aspects of HCl corrosion, detailing the behavior of both metallic and non-metallic materials.

Hydrofluoric Acid Corrosion

Hydrofluoric acid (HF) corrosion is predominantly connected to allylation units that incorporate this acid. The corrosive nature of HF, akin to hydrochloric acid (HCl), poses a significant challenge in material selection due to its high aggressiveness in aqueous solutions. This chapter delves into the intricacies of HF corrosion, exploring its various characteristics and critical parameters. Understanding the corrosive mechanisms and vulnerabilities is essential for developing effective mitigation strategies

Sulfuric Acid Corrosion

Sulfuric acid is used as a supportive chemical in a variety of processes, mostly acting as a neutralizing agent, for example, in Condensate Polishing units, as a catalyst in alkylation units, and as a catalyst in esterification reactions. Despite relatively well-understood knowledge about the behavior of metallic materials in the presence of sulfuric acid (H2SO4), some unexpected failures still occur. This chapter provides general information on H2SO4 corrosion, the correlation between process parameters and corrosion, and some guidelines to mitigate the risk of failures in in H2SO4 systems.