King Saud University, Saudi Arabia CO2 Capture Using Deep Eutectic Solvents Prof.  Emadadeen  M.  Ali King Saud University, Saudi Arabia

Global Worming Global Warming Fossil fuels (coal, oil, natural gas) Carbon Dioxide (CO2) Fossil fuels (coal, oil, natural gas)

Sources of CO2 emissions

World-wide statistical data of CO2

CO2 separation process Separation using Sorbent/Solvent

Solvent Characteristics Preparation and material Cost Environmental impact Capacity

MEA Advantage & Disadvantages MEA: Monoethanolamin is the most common material used in industry to absorb CO2 Advantages Inexpensive material (1ton of MEA cost $1100) Disadvantages Low carbon dioxide loading capacity Equipment corrosion High-energy penalty during absorbent regeneration

Ionic Liquids A new class of compounds that have emerged in the last twenty years with several applications in chemical and physical separation. ILs are environmentally-friendly alternatives to organic solvent for liquid/liquid extraction, and separation. ILs face a challenge in large-scale industrial applications, due to complicated synthetic processes and the expensive raw material chemicals

Deep Eutectic Solvents deep eutectic solvents (DESs) have been recognized as a cost effective alternative to ILs DESs possess several advantages over traditional ILs., they can be prepared easily in high purity at low cost. In addition, they are non-toxic, have no reactivity with water and most importantly being biodegradable

Objectives Prepare different types of DES Test the solubility of CO2 in these DES Model the CO2 solubility using Peng-Robinson EoS

EC 400 Variable volume high pressure equilibrium cell (SEPAREX, France).

Experiment Protocol The visual cell is cleaned, evacuated using vacuum pump, and kept at fixed temperature using a circulating water bath. A pre-determined amount of DES is introduced to the cell using the HPLC pump. CO2 is then introduced to the cell at a certain pressure. The mixture is stirred using the magnetic bar until equilibrium is achieved. The change in the volume of cell is recorded. The mass of dissolved CO2 is calculated using Benedict-Webb-Robin equation of state

Solubility Modeling Peng Robinson Equation of State Subject to:

Solubility and physical properties of DES at T=25 oC, P=125 psi Code Components Ratio x Tc, K Pc, bar w D01 Bc Glycerol 1 12 0.0511 749.0 34.1 1.4 D02 Bb Ethylene Glycol 0.0503 632.3 46.5 1.0 D03 Mb Ethanol Amine 6 0.1441 654.1 44.0 0.7 D04 7 0.1254 646.0 45.1 D05 8 0.1189 639.8 46.1 D06 CC 0.1096 594.1 48.9 D07 Di Ethanol Amine 0.0925 693.4 29.7 1.1 D08 TAB 0.1168 613.8 39.2 D09 0.1036 717.7 25.5 D10 Tri Ethanol Amine 3 0.0830 795.7 19.3 BC: Benzyltryphenilphosphonium chloride, BB:n-Butyltriphenylphosphonium bromide, MB: Methyltriphenylphosphonium bromide, TAB: Tetra Butyl Ammonium Bromide

Solubility and physical properties of CC-salt /des at T=25 oC Code Components Ratio Pressure (bar) x Tc, K Pc, bar w I2 CC TG 1 4 1.38 0.0003 718.9 27.4 1.04 5.12 0.0021 8.61 0.0028 13.80 0.0101 CC: Choline Chloride, TG: Triethylene Glycol

Comparison of CO2 solubility in DESs, ♦: experimental; ▲: model; □: corrected model

: CO2 solubility in CC-based DEs with pressure, ♦: experimental; ▲: model with fixed k; □: model with variable k

Conclusions The solubility of CO2 in ethylene glycol and glycerol based DESs is much smaller than that in MEA aqueous solution The solubility depended on the type of salt used and on the salt:HBD molar ratio. The modeling results indicated the necessity to adjust the interaction parameter in order to improve the ability of the PR EoS to predict the CO2 solubility

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