Browsing by Author "Un, Umran Tezcan"

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Carbon Dioxide Absorption Using Different Solvents (Mea, Naoh, Koh and Mg(Oh)2) in Bubble Column Reactor
(2023) Gul, Ayse; Un, Umran Tezcan
The aim of this research is to reduce emissions by capturing carbon dioxide in a solution using an absorption method. The absorption capacity, absorption rate, carbon dioxide removal efficiency, and overall mass transfer coefficient of MEA (Monoethanolamin) and alkaline solvents (NaOH, KOH, Mg(OH)2) were investigated using a bubble column gas absorption reactor with counter current flow. The effects of operational parameters such as solvent concentration (0.01, 0.05, and 0.25M) and solvent type were studied. As a result of the study, it was determined that Mg(OH)2 was less effective in capturing CO2 than KOH, NaOH, and MEA. For all solvent types, the total mass transfer coefficient, absorption rate, and CO2 removal efficiency were increased with the increase in the concentration of solvent. The solvent concentration is increased from 0.01 M to 0.25 M to obtain the highest KGa values for MEA, NaOH, and KOH, 3.75 1/min for MEA, 3.70 1/min for NaOH, and 3.93 1/min for KOH.The MEA, NaOH, and KOH absorption rates were maximum at 0.25 M solvent concentrations as 0.19x103 mol/Ls. The maximum CO2 removal efficiencies for MEA, NaOH, and KOH at 0.25 M solvent concentration are greater than 60%. The highest absorption capacity, 0.576 mol CO2/mol MEA, was obtained at a solvent concentration of 0.01M MEA.
Citation - WoS: 6
Citation - Scopus: 9
Carbon Dioxide Absorption Using Monoethanolamine, Piperazine and N-Metil Solvents Under Counter Current Regime in Packed Column Reactor
(Elsevier Sci Ltd, 2024) Gul, Ayse; Baris, Mesut; Un, Umran Tezcan
In this research the carbon dioxide absorption using Monoethanolamine (MEA), Piperazine (PZ) and N-Metil-2-pirolidon (NMP) solvents and their different blends (MEA/NMP, PZ/NMP, MEA/PZ) in packed column reactor filled with Raschig rings was investigated and compared for efficient carbon dioxide absorption. The process was followed in a countercurrent regime under a liquid flow rate of 200 mL/min, gas flow rate of 2.5 L/min, and CO2 concentration of 50,000 ppm. Carbon dioxide removal efficiency (%), absorption capacity (mol CO2/mol solvent), overall mass transfer coefficient (1/min) and absorption rate (mol/l.s) were monitored. The highest obtained values for carbon dioxide removal efficiency, absorption capacity and overall mass transfer coefficient were 57.5%, 0.148 mol CO2/mol solvent and 2.178 min-1 respectivelly when 0.03 M MEA/0.07 M PZ in a hybrid system was used. It was concluded that PZ blends with MEA were successful absorbent as the organic physical solvent whereas NMP didn't show improving effect in blends with MEA on the absorption efficiency.
Citation - WoS: 3
Citation - Scopus: 3
Optimization of Carbon Dioxide Absorption in a Continuous Bubble Column Reactor Using Response Surface Methodology
(Wiley, 2023) Gul, Ayse; Derakhshandeh, Masoud; Un, Umran Tezcan
Carbon dioxide absorption using amine based solvents is a well-known approach for carbon dioxide removal. Especially with the increasing concerns about greenhouse gas emissions, there is a need for an optimization approach capable of multifactor calibration and prediction of interactions. Since conventional methods based on empirical relations are not efficiently applicable, this study investigates use of Response Surface Methodology as a strong optimization tool. A bubble column reactor was used and the effect of solvent concentration (10.0, 20.0 and 30.0 vol%), flow rate (4.0, 5.0 and 6.0 L min-1), diffuser pore size (0.5, 1.0 and 1.5 mm) and temperature (20.0, 25.0 and 30.0 degrees C) on the absorption capacity and also overall mass transfer coefficient was evaluated. The optimization results for maintaining maximum capacity and overall mass transfer coefficient revealed that different optimization targets led to different tuned operational factors. Overall mass transfer coefficient decreased to 34.7 min-1 when the maximum capacity was the desired target. High reaction rate along with the highest absorption capacity was set as desirable two factor target in this application. As a result, a third scenario was designed to maximize both mass transfer coefficient and absorption capacity simultaneously. The optimized condition was achieved when a gas flow rate of 5.9 L min-1, MEA solution of 29.6 vol%, diffuser pore size of 0.5 mm and temperature of 20.6 degrees C was adjusted. At this condition, mass transfer coefficient reached a maximum of 38.4 min-1, with a forecasted achievable absorption capacity of 120.5 g CO2 per kg MEA.