Dynamic phase-splitting behaviour of biphasic solvent for carbon capture in a novel annular phase separator

Compared with biphasic solvents with blend amines, the mixture of physical solvent, amines and water (ternary solvent) was a promising preparation strategy. Chemical CO 2 absorption with amine-based solvents is a promising route for industrial CO 2 capture, but suffering from intensive heat duty for solvent regeneration. Developing high-performance biphasic solvent and efficient dynamic phase separator is an effective solution. In this study, poly(ethylene glycol) dimethyl ether (NHD) was selected as the separating agent to prepare a biphasic solvent based on a blended amine (Diethylenetriamine (DETA) and N , N -dimethylcyclohexylamine (DMCA) solvent with a screened proportion of DETA: DMCA: NHD: H 2 O of 1:3:4:2. The CO 2 loading of the saturated solvent was 4.6 mol·L −1 , with over 96% of the CO 2 species concentrated in the rich phase, and with low viscosity of 48.60 mPa·s. The maximum desorption rate of CO 2 -saturated solvent was up to 1.68 mmol·min −1 , and it increased by 243% compared to the MEA solvent (30 wt% MEA and 70 wt% water). The intermediates in various phases were identified using NMR to monitor the species changes during phase splitting. The dynamic phase-splitting capacity was first determined using a quasi-two-dimensional separator, and the results revealed that the liquid velocity of the mixed phase had a dominant effect on the separation efficiency. Furthermore, a novel annular phase separator was proposed to achieve efficient phase separation (the relatively rich separation efficiency increased by 13.40% compared to that with the benchmark.) by decreasing the tangential turbulence from the inlet velocity . The time–space distribution of the CO 2 loading was obtained at different operational parameters. In particular, the effect of water content on separation efficiency was investigated to verify the adaptability of biphasic solvents for practical application.