Corrosion Challenges in Hydrocracker Unit: Comprehensive Review

Abstract Hydrocracking units are versatile units in the refinery application. Their common goals are producing low-sulfur refinery products and cracking larger gasoil feeds into higher-demand jet or diesel range hydrocarbons. This unit utilizes hydrogen and operates at high elevated temperatures and pressures to improve the quality of the different feedstock. Hydrogen sulfide (H2S) ammonium bisulfide (NH4HS) and ammonia (NH3) are produced from the reaction of hydrogen with sulfur and other nitrogen compounds present in the hydrocarbon feed. Several other reactions can also occur, including converting any chlorides in the feed to hydrochloric acid (HCl) and ammonium chlorides (NH3CL). Hydrocracking units contain various corrodent compounds which will produce serious corrosion impact on different metallurgy in various temperature zones. Corrosion in hydrocracking units can be minimized with various factors such as control over composition, phase state, temperature, pressure, equipment selection, metallurgy, and application of anti-corrosion measures. However, the industry is still facing multiple challenges due to certain controlling factors beyond their control which is directly impacting production loss and economic impacts to the operators. Furthermore, the prediction of corrosion in hydrocracking units has become a challenging subject due to significant changes in the crude composition of the original design, which necessitates the upgradation of metallurgy to overcome the corrosion issues in this unit. This paper will focus on corrosion failure analysis associated with hydrocracking units, which will help the industry to focus on the right area either in existing plants or new construction to avoid similar deficiencies, prevent failure, and avoid any economic impact to the operator in the near future.