(148c) Piperazine-Activated Mdea: Challenges in Modeling Vapor-Liquid Equilibrium and the Effect of CO2 Loading on Solvent Viscosity

MDEA activated with piperazine (aMDEA) has become a key player in the deep removal of carbon dioxide for LNG applications. Because of the high reactivity of piperazine towards CO₂, obtaining reliable VLE data is even more difficult than with less reactive amines. If samples are not properly collected and handled during experimentation, piperazine promoted MDEA can absorb CO₂ from atmospheric air, significantly affecting the accuracy of experimental measurements. This presents a challenge when trying to accurately develop models for aMDEA. In cases where the solvent is nearly free of CO₂, VLE or plant measured lean CO₂ loadings may be more representative of the level of air contamination rather than the actual CO₂ present in the process or VLE cell.

Piperazine viscosity, and subsequently piperazine-activated MDEA viscosity, has been found to be a strong function of CO₂ loading. The viscosity of a solvent plays a key part in treating performance. The same concerns of air contamination for VLE apply to prior viscosity measurements that have been collected over the years. A case study using the ProTreat® rate-based gas treating simulator will be utilized in quantitating the impacts of these data uncertainties on the performance of a commercial LNG treating application.