Salt management strategy on the design of MEG (Mono Ethylene Glycol) regeneration process for LNG FPSO

Abstract

MEG (Mono Ethylene Glycol) is usually used as a gas hydrate inhibitor, and it is essential to regenerate and re-inject this into well because great amount of MEG is consumed to control gas hydrate. Therefore, MEG regeneration process is installed in LNG FPSO, and used MEG is regenerated from this. It is important to know the salts equilibrium under MEG regeneration conditions in order to prevent problems related to deposition and scale precipitation. We conducted experiments and process simulations. Through the simulation, we simulated energy consumption at each regeneration concept and analyzed optimum condition at pre-treatment zone. Also, we did simulation on low soluble salts deposition with ELECNRTL model. We measured density, conductivity, pH through experiments. In the experiment, we measured the property that high soluble salts, NaCl and low soluble salts, CaCO3 have in MEG solution. Measurement value and simulation value were compared and analyzed. In (CO2 + water) system or (CO2) system, it was possible to predict from the simulation. But in the system with coexisting CaCO3, CO2, and MEG, we figured that the simulation result needs to be adjusted through experiments. In this paper, we conducted simulations and experiments on temperature, pressure condition (MEG, CO2, CaCO3, NaCl) of MEG regeneration.