Solid–Liquid Equilibria of a 30 wt % Aqueous Monoethanolamine Solution Containing Urea and Monoethylene Glycol

Abstract

The solid-liquid phase boundaries on new innovative solvents for the carbon capture and storage (CCS) technology have been measured in this work. The solvents have been formulated with vapour reduction additives (VRAs) also known as water lean solvents. The solid-liquid equilibrium (SLE) data will create better prediction models for the CCS technology and prevent precipitation in process equipment and thereby reduce the risk of costly shutdowns. The presented SLE data cannot be used in the prediction of solid formation in condenser as it would require knowledge of the vapour-liquid-solid equilibria. 2The SLE of the systems urea-H2O, urea-monoethanolamine (MEA)-H2O, and monoethylene glycol (MEG)-H2O have been determined using the methods freezing point depression (FPD) and SLE by FPD. 61 new SLE data points are listed of 0 < w(urea) < 60 %, and 0 < w(MEG) < 20 %.It is the first time that the ternary systems have been measured. The eutectic temperatures were found at -8 °C for urea-H2O and -27 °C for urea-MEA-H2O. Highly concentrated urea solutions freeze completely upon mixing water with MEA due to the endothermic reaction. Solubility data of MEG-MEA-H2O was found for t > -40 °C. All SLE points for MEG in 30 wt% aqueous MEA freezes below -15 °C.To avoid clogging from urea precipitation, it is recommended to use urea below 30 wt%.

New Process for Na2CO3 Production from Na2SO4 Based on Modeling the Na2SO4–(NH4)2SO4–MEA–MEG–H2O System

“…Solid–liquid equilibria of Na 2 SO 4 and (NH 4 ) 2 SO 4 in an aqueous mixture of MEA and MEG play an important role in the design and engineering scale-up of their crystallization separation. Neerup et al determined the solubility of ice and urea in two systems: urea–MEA–H 2 O and MEG–MEA–H 2 O for the improvement of thermodynamic modeling of new CO 2 solvents. The Pitzer–Lorimer approach was recently used to correlate eight salts’ solubility data in water–MEG mixtures with adequate results.…”

Influence of CO2 on the Solubility of Potassium Glycinate in Glycine–KOH–H2O, Glycine–KHCO3–H2O, and Glycine–KOH–KHCO3–H2O

“…A drawback of using an amine such as MEA is the high energy consumption required for solvent regeneration . Solid precipitation is another potential drawback of the utilization of amines in the CO 2 capture process. − …”