Study of Waste MDEA Characteristics through Neutralization with Caustic

• Main Author: Atikah Bt. Mohd. Jehan Zaib, Atikah
• Format: Final Year Project
• Language: English
• Published: UNIVERSITI TEKNOLOGI PETRONAS 2010
• Subjects: TP Chemical technology
• Online Access: http://utpedia.utp.edu.my/375/1/Final_Report_FINAL.pdf; http://utpedia.utp.edu.my/375/

This report aims to study the by-product formation and potential harm it may cause to the MDEA at different strengths of amine, to determine the MDEA characteristics after caustic is added and provide qualitative measure of HSS contamination and to determine the feasibility of adding caustic to neutralise MDEA is applicable to Amines system in the refinery. Amines is a class of organic compounds of nitrogen that may be considered as derivation of ammonia (NH3) by replacing one or more of the hydrogen atoms with alkyl groups. The amine is primary (MEA), secondary (DEA), or tertiary (MDEA) depending on whether one, two, or three of the hydrogen atoms are replaced. MDEA has become more and more preferable for amine gas sweetening due to its stability. From the experiments conducted, it is clear that neutralization with KOH is favorable. This is because neutralization changes the corrosive HSS which is formate and acetate to HSAS which is less corrosive to an amine system. From the TAN obtained, KOH effectively neutralized the high amount of acid in the solution. The byproduct (HSAS) which are potassium acetate and potassium formate produced in this neutralization is more harmless than the HSS (formate and acetate) before neutralization. MDEA characteristics and basicity is also retained after neutralization. KOH addition to neutralize HSS is therefore suitable as a short term measure of purging the amine system. It is recommended to be added after the amine has gone through the regenerator to prevent the KOH from neutralizing H2S instead. The MDEA concentration that is above 30% and less than 50% seems to be the best concentration against contaminants in the system. Neutralization with KOH is deemed feasible for application in an amine gas treating plant. It is recommended to investigate MDEA at other strengths (wt %) such as 25, 35, 45 and 55% as well.