title: Measuring the Absorption Rate of CO2 in Nonaqueous CO2-Binding Organic Liquid Solvents with a Wetted-Wall Apparatus.
abstract: The kinetics of the absorption of CO2 into two nonaqueous CO2-binding organic liquid (CO2 BOL) solvents were measured at T=35, 45, and 55 °C with a wetted-wall column. Selected CO2 loadings were run with a so-called "first-generation" CO2 BOL, comprising an independent base and alcohol, and a "second-generation" CO2 BOL, in which the base and alcohol were conjoined. Liquid-film mass-transfer coefficient (k'g ) values for both solvents were measured to be comparable to values for monoethanolamine and piperazine aqueous solvents under a comparable driving force, in spite of far higher solution viscosities. An inverse temperature dependence of the k'g value was also observed, which suggests that the physical solubility of CO2 in organic liquids may be making CO2 mass transfer faster than expected. Aspen Plus software was used to model the kinetic data and compare the CO2 absorption behavior of nonaqueous solvents with that of aqueous solvent platforms. This work continues our development of the CO2 BOL solvents. Previous work established the thermodynamic properties related to CO2 capture. The present paper quantitatively studies the kinetics of CO2 capture and develops a rate-based model.
authors.affiliation: Process Technology, Fluor Corporation, 3 Polaris Way, Aliso Viejo, CA, 92698, USA.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Mathias
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
authors.forename: Feng
authors.initials: F
authors.lastname: Zheng
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA. david.heldebrant@pnnl.gov.
authors.forename: David J
authors.initials: DJ
authors.lastname: Heldebrant
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
authors.forename: Andy
authors.initials: A
authors.lastname: Zwoster
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
authors.forename: Greg
authors.initials: G
authors.lastname: Whyatt
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Freeman
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
authors.forename: Mark D
authors.initials: MD
authors.lastname: Bearden
authors.affiliation: Energy and Environment Directorate, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA, 99352, USA.
authors.forename: Phillip
authors.initials: P
authors.lastname: Koech
mesh_terms: D065966:Absorption, Physicochemical; D002245:Carbon Dioxide / Q000737:chemistry / Q000302:isolation & purification*; D048289:Imidazolidines / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D012995:Solubility; D012997:Solvents / Q000737:chemistry*; D013696:Temperature; D013816:Thermodynamics; D014783:Viscosity; D018505:Waste Management / Q000295:instrumentation / Q000379:methods; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D048289:Imidazolidines; D012997:Solvents; D014867:Water; D002245:Carbon Dioxide
keywords: absorption; carbon dioxide; ionic liquids; kinetics; solvent effects