scholarly journals Conjugated Mass Transfer of CO2 Absorption through Concentric Circular Gas–Liquid Membrane Contactors

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1580
Author(s):  
Chii-Dong Ho ◽  
Hsuan Chang ◽  
Yih-Hang Chen ◽  
Jun-Wei Lim ◽  
Jing-Wei Liou
Keyword(s):  
Mass Transfer ◽  
Analytical Solutions ◽  
Absorption Rate ◽  
Liquid Membrane ◽  
Absorption Efficiency ◽  
Experimental Results ◽  
Co2 Absorption ◽  
Countercurrent Flow ◽  
Theoretical Predictions ◽  
Membrane Contactors

A new design of gas absorption that winds the permeable membrane onto an inner concentric tube to conduct a concentric circular gas–liquid membrane module has been studied theoretically in the fully developed region. An analytical formulation, referred to as conjugated Graetz problems, is developed to predict the concentration distribution and Sherwood numbers for the absorbent fluid flowing in the shell side and CO2/N2 gas mixture flowing in the tube side under various designs and operating parameters. The analytical solutions to the CO2 absorption efficiency were developed by using a two-dimensional mathematical modeling, and the resultant conjugated partial differential equations were solved analytically using the method of separation variables and eigen-function expansion in terms of power series. The predictions of CO2 absorption rate by using Monoethanolamide (MEA) solution in concentric circular membrane contactors under both concurrent- and countercurrent-flow operations are developed theoretically and confirmed with the experimental results. Consistency in both a good qualitative and quantitative sense is achieved between the theoretical predictions and experimental results. The advantage of the present mathematical treatment provides a concise expression for the chemical absorption of CO2 by MEA solution to calculate the absorption rate, absorption efficiency, and average Sherwood number. The concentration profiles with the mass-transfer Graetz number, inlet CO2 concentration, and both gas feed and absorbent flow rates are also emphasized. Both theoretical predictions and experimental results show that the device performance of the countercurrent-flow operation is better than that of the concurrent-flow device operation. The availability of such simplified expressions of the absorption rate and averaged Sherwood as developed directly from the analytical solutions is the value of the present study.

scholarly journals Augmenting CO2 Absorption Flux through a Gas–Liquid Membrane Module by Inserting Carbon-Fiber Spacers

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 302
Author(s):  
Luke Chen ◽  
Chii-Dong Ho ◽  
Li-Yang Jen ◽  
Jun-Wei Lim ◽  
Yu-Han Chen
Keyword(s):  
Experimental Data ◽  
Carbon Dioxide ◽  
Carbon Fiber ◽  
Flow Rate ◽  
Absorption Rate ◽  
Absorption Efficiency ◽  
Co2 Absorption ◽  
Countercurrent Flow ◽  
Carbon Dioxide Absorption ◽  
Ptfe Membrane

We investigated the insertion of eddy promoters into a parallel-plate gas–liquid polytetrafluoroethylene (PTFE) membrane contactor to effectively enhance carbon dioxide absorption through aqueous amine solutions (monoethanolamide—MEA). In this study, a theoretical model was established and experimental work was performed to predict and to compare carbon dioxide absorption efficiency under concurrent- and countercurrent-flow operations for various MEA feed flow rates, inlet CO2 concentrations, and channel design conditions. A Sherwood number’s correlated expression was formulated, incorporating experimental data to estimate the mass transfer coefficient of the CO2 absorption in MEA flowing through a PTFE membrane. Theoretical predictions were calculated and validated through experimental data for the augmented CO2 absorption efficiency by inserting carbon-fiber spacers as an eddy promoter to reduce the concentration polarization effect. The study determined that a higher MEA feed rate, a lower feed CO2 concentration, and wider carbon-fiber spacers resulted in a higher CO2 absorption rate for concurrent- and countercurrent-flow operations. A maximum of 80% CO2 absorption efficiency enhancement was found in the device by inserting carbon-fiber spacers, as compared to that in the empty channel device. The overall CO2 absorption rate was higher for countercurrent operation than that for concurrent operation. We evaluated the effectiveness of power utilization in augmenting the CO2 absorption rate by inserting carbon-fiber spacers in the MEA feed channel and concluded that the higher the flow rate, the lower the power utilization’s effectiveness. Therefore, to increase the CO2 absorption flux, widening carbon-fiber spacers was determined to be more effective than increasing the MEA feed flow rate.

scholarly journals Enhancing Absorption Performance of CO2 by Amine Solution through the Spiral Wired Channel in Concentric Circular Membrane Contactors

Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 4
Author(s):  
Chii-Dong Ho ◽  
Hsuan Chang ◽  
Guan-Hong Lin ◽  
Thiam Leng Chew
Keyword(s):  
Flow Rate ◽  
Absorption Rate ◽  
Concentration Polarization ◽  
Co2 Concentration ◽  
Co2 Absorption ◽  
Countercurrent Flow ◽  
Circular Membrane ◽  
Concurrent Flow ◽  
Amine Solution ◽  
Membrane Contactors

The CO2 absorption rate by using a Monoethanolamide (MEA) solution through the spiral wired channel in concentric circular membrane contactors under both concurrent-flow and countercurrent-flow operations was investigated experimentally and theoretically. The one-dimensional mathematical modeling equation developed for predicting the absorption rate and concentration distributions was solved numerically using the fourth Runge–Kutta method under various absorbent flow rate, CO2 feed flow rate and inlet CO2 concentration in the gas feed. An economical viewpoint of the spiral wired module was examined by assessing both absorption flux improvement and power consumption increment. Meanwhile, the correlated average Sherwood number to predict the mass-transfer coefficient of the CO2 absorption mechanisms in a concentric circular membrane contactor with the spiral wired annulus channel is also obtained in a generalized and simplified expression. The theoretical predictions of absorption flux improvement were validated by experimental results in good agreements. The amine solution flowing through the annulus of a concentric circular tube, which was inserted in a tight-fitting spiral wire in a small annular spacing, could enhance the CO2 absorption flux improvement due to reduction of the concentration polarization effect. A larger concentration polarization coefficient (CPC) was achieved in the countercurrent-flow operations than that in concurrent-flow operations for various operations conditions and spiral-wire pitches. The absorption flux improvement for inserting spiral wire in the concentric circular module could provide the maximum relative increment up to 46.45%.

scholarly journals Selection of Mixed Amines in the CO2 Capture Process

2021 ◽  
Vol 7 (1) ◽  
pp. 25
Author(s):  
Pao-Chi Chen ◽  
Hsun-Huang Cho ◽  
Jyun-Hong Jhuang ◽  
Cheng-Hao Ku
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Co2 Capture ◽  
Absorption Rate ◽  
Absorption Efficiency ◽  
Optimum Conditions ◽  
Capture Process ◽  
Overall Mass Transfer Coefficient ◽  
Selection Of

In order to select the best mixed amines in the CO2 capture process, the absorption of CO2 in mixed amines was explored at the required concentrations by using monoethanolamine (MEA) as a basic solvent, mixed with diisopropanolamine (DIPA), triethanolamine (TEA), 2-amino-2-methyl-1-propanol (AMP), and piperazine (PZ). Here, a bubble column was used as the scrubber, and a continuous operation was adopted. The Taguchi method was used for the experimental design. The conditional factors included the type of mixed amine (A), the ratio of the mixed amines (B), the liquid feed flow (C), the gas-flow rate (D), and the concentration of mixed amines (E). There were four levels, respectively, and a total of 16 experiments. The absorption efficiency (EF), absorption rate (RA), overall mass transfer coefficient (KGa), and scrubbing factor (ϕ) were used as indicators and were determined in a steady-state by the mass balance and two-film models. According to the Taguchi analysis, the importance of the parameters and the optimum conditions were obtained. In terms of the absorption efficiency (EF), the absorption rate (absorption factor) (RA/ϕ), and the overall mass transfer coefficient (KGa), the order of importance is D > E > A > B > C, D > E > C > B > A, and D > E > C > A > B, respectively, and the optimum conditions are A1B4C4D3E3, A1B3C4D4E2, A4B2C3D4E4, and A1B1C1D4E1. The optimum condition validation results showed that the optimal values of EF, RA, and KGa are 100%, 30.69 × 10−4 mol/s·L, 1.540 l/s, and 0.269, respectively. With regard to the selection of mixed amine, it was found that the mixed amine (MEA + AMP) performed the best in the CO2 capture process.

Gas/liquid membrane contactors based on disubstituted polyacetylene for CO2 absorption liquid regeneration at high pressure and temperature

2011 ◽  
Vol 383 (1-2) ◽  
pp. 241-249 ◽  
Author(s):  
Alexander Trusov ◽  
Sergey Legkov ◽  
Leo J.P. van den Broeke ◽  
Earl Goetheer ◽  
Valery Khotimsky ◽  
...  
Keyword(s):  
High Pressure ◽  
Liquid Membrane ◽  
Co2 Absorption ◽  
High Pressure And Temperature ◽  
Membrane Contactors

scholarly journals Optimization in the Absorption and Desorption of CO2 Using Sodium Glycinate Solution

2018 ◽  
Vol 8 (11) ◽  
pp. 2041 ◽  
Author(s):  
Pao Chi Chen ◽  
Sheng-Zhong Lin
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Flow Rate ◽  
Bubble Column ◽  
Absorption Efficiency ◽  
Operating Conditions ◽  
Flow Rate Ratio ◽  
Optimum Operating ◽  
Co2 Absorption

This study used sodium glycinate as an absorbent to absorb CO2 in the bubble column scrubber under constant pH and temperature environments to obtain the operating range, CO2 loading, and mass transfer coefficient. For efficient experimentation, the Taguchi method is used for the experimental design. The process parameters are the pH, gas flow rate (Qg), liquid temperature (T), and absorbent concentration (CL). The effects of the parameters on the absorption efficiency, absorption rate, overall mass transfer coefficient, gas–liquid molar flow rate ratio, CO2 loading, and absorption factor are to be explored. The optimum operating conditions and the order of parameter importance are obtained using the signal/noise (S/N) ratio analysis, and the optimum operating conditions are further verified. The verification of the optimum values was also carried out. The order of parameter importance is pH > CL > Qg > T. Evidence in the 13CNMR (Carbon 13 Nuclear Magnetic Resonance) spectra shows that the pH value has an effect on the solution composition, which affects both the absorption efficiency and mass transfer coefficient. There are 18 experiments for regeneration, where the operating temperature is 100–120 °C. The heat of regeneration was measured according to the thermodynamic data. The CO2 loading, the overall mass transfer, and the heats of regeneration correlation are also discussed in this work. Finally, an operating policy for the CO2 absorption process was confirmed.

Experimental Study on Mass Transfer Performances in a New Rotating Packed Bed

2013 ◽  
Vol 726-731 ◽  
pp. 2182-2185
Author(s):  
Li Juan He ◽  
Jie Qiong Li ◽  
Yan Ling Ni ◽  
Jun Hua Yi ◽  
Wen Fei Wu
Keyword(s):  
Mass Transfer ◽  
Experimental Study ◽  
Flue Gas ◽  
Packed Bed ◽  
Absorption Efficiency ◽  
Experimental Results ◽  
Liquid Equilibrium ◽  
Experimental Conditions ◽  
Rotating Packed Bed ◽  
The Given

Based on the vapor-liquid equilibrium principle, a new rotating packed absorption tower was presented against some traditional gas-liquid countercurrent tower defects. An experimental device was built to test CO2 absorption efficiency in the packed absorption tower under the given experimental conditions. The experimental results show that the new packed absorption tower can capture the simulated flue gas CO2 and have a higher efficiency 87.8%.

Enhanced Absorption of Carbon Dioxide Gas by Methanol Based Nanofluids in a Taylor-Couette Absorber

2013 ◽  
Author(s):  
Israel Torres Pineda ◽  
Yong Tae Kang
Keyword(s):  
Carbon Dioxide ◽  
Mass Transfer ◽  
Mass Flow ◽  
High Speed ◽  
Absorption Rate ◽  
Gas Absorption ◽  
Co2 Absorption ◽  
Co2 Gas ◽  
Enhanced Absorption ◽  
Taylor Couette

Mass transfer enhancement by the use of nanoparticles suspended in a liquid phase (known as nanofluids) has been studied in recent years with positive results. Different theories have been proposed to explain the improvement in mass transfer, however it has not been possible to elucidate a definite answer. While the theory is still uncertain the experimental work continues in areas that will benefit much such as non-reactive gas absorption. In this study carbon dioxide (CO2) absorption experiments are performed in a Taylor-Couette absorber at different rotational speeds. The base fluid for the experiments is methanol. Al2O3 and SiO2 nanoparticles are combined with methanol to produce nanofluids with the purpose of enhancing the absorption of the CO2 gas into the methanol. The system is equipped with a mass flow controller at the inlet and a mass flow meter at the outlet to obtain the absorption rate. The Taylor-Couette absorber performance is compared to a modified version in which trays were added to enhance the absorption rate. Experiments in co-current and counter-current flow modes are carried out. The results of continuous absorption are presented. In addition, the two-phase flow pattern of the CO2 gas bubbles and the liquid methanol in the Taylor-Couette absorber and the modified version is analyzed with pictures obtained by a high speed camera.

Sign in / Sign up

Export Citation Format

Share Document