• Applied Chemistry for Engineering
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• v.21 no.2
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• pp.195-199
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• 2010

The reversible chemical absorption using MEA (monoethanolamine), one of alkanolamine, is generally used as a conventionally method for $CO_{2}$ capture. Even MEA absorbent has excellent reactivity with $CO_{2}$, it has been known to have the decrease of absorption capacity caused by $CO_{2}$, $O_{2}$ or other acid gases in flue gas, corrosion and thermal degradation. In this study, MEA solutions degraded in the steam reforming process of refinery used and the absorption performance were compared for the used of conventional MEA solution. In case of 30 wt% MEA and mixture of 20 wt% thermal degraded absorbent (DP) and 10 wt% PZ, the absorption capacities were $0.5365mol-CO_{2}$/mol-absorbent and $0.5939mol-CO_{2}$/mol-absorbent respectively. PZ added thermally degraded absorbent showed the enhanced absorption capacity. On the contrary, the absorption rates were $1.1610kg_{f}/cm^2{\cdot}min$ for 30 wt% MEA, $0.5310kg_{f}/cm^2{\cdot}min$ for mixture of 20 wt% thermal degraded absorbent (DP) and 10 wt% PZ and $0.3525kg_{f}/cm^2{\cdot}min$ for 30 wt% thermally degraded absorbent only. The absorption rates of PZ added thermally degraded absorbent was higher than that of thermally degraded absorbent only. Therefore, it can be confirmed that thermally degraded absorbent can be reused as an absorbent for $CO_{2}$ by the addition of suitable additives.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.1
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• pp.65-69
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• 2004

Screen printing it one of the most popular methods for the fabrication of catalytic layer in electrode of polymer electrolyte membrane fuel cells (PEMFCs) due to its convenience and adaptability. This paper suggests an improved screen-printing method, which is rather simple suppressing the swelling trouble without additive process and competitive with very low Pt loading in comparison with the previous methods. Particularly, the gasket unified MEA made better performances than the other especially at high current area due to blocking effect on the gas leakage during the operation. These methods give us more simplified and faster fabrication chances.

• Journal of the Microelectronics and Packaging Society
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• v.11 no.1
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• pp.59-64
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• 2004

The performance of fuel cell electrode depends on the characteristics of the catalyst support material. This paper deals with the use of CNF(carbon nanofibre) and CNT(carbon nanotube) as platinum catalyst support. The CNF and CNT were synthesized with catalyst treated by mechanochemical process and were prepared by chemical vapor deposition (CVD) method. The platinum supported on CNF and CNT for polymer electrolyte membrane fuel cell (PEMFC) application. In result, the best I-V characteristic was verified by the prepared MEA(membrane electrode assembly) from twisted CNF that had a diameter of 65 nm.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.110-112
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• 2006

Membrane electrode assembly (MEA) for polymer electrolyte fuel cell (PEFC) are commonly prepared in the research laboratory by spraying, screen-printing and brushing catalyst slurry onto membrane or other support material like carbon paper or polyimide film in a batch style. These hand applications of the catalyst slurry are painstaking process with respect to precision of catalyst loading and reproducibility. It has been generally mentioned that the adoption of continuous process is very helpful to develop the reliable product. In the present work, we report the results of using continuous type coater with doctor-blade to coat catalyst slurry for preparing the MEA catalyst layers In a faster and highly reproducible fashion. We show that while expectedly faster than batch style, the machine coater requires the use of slurry of appropriate composition and a properly selected transfer decal material in order to achieve superior MEA plat lnw loading reproducibility. To make highly viscous catalyst slurry that is imperative for using coater, we use 40wt.% Nafion solution and minimize the content of organic solvent. And the choice of proper high surface area catalyst is important in the viewpoint of making well-dispersed slurry. After catalyst coating onto the support material, we transferred the catalyst layer to both sides of Nafion membrane by hot-pressing In this case, the degree of transfer was Influenced by hot-pressing condition including temperature, pressure, and time. To compare the transferring ability, we compared so many films and detaching papers. And among the support, polyethylene terephthalate(PET) film shows the prominent result.

• Journal of the Korean Institute of Gas
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• v.27 no.2
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• pp.25-31
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• 2023

The purpose of this study is to increase the thermal efficiency of a landfill gas (LFG) power generation engine by capturing carbon dioxide (CO₂) from landfill gas (LFG) using monoethanolamine (MEA), which is widely used in the chemical CO₂ absorption process. Since the use of LFG as an energy source can be a means of reducing greenhouse gas emissions, MEA can be used to reduce CO₂ in LFG and increase the concentration of CH₄ to improve the efficiency of power generation. In this study, experiments were conducted to measure the solubility of CO₂ and CH₄ in MEA solution, increase the solubility under different conditions, and analyse the dissolution characteristics. It was found that the CO₂ absorption rate increased as the ratio of MEA to reaction gas increased. There is an optimum MEA concentration to maximise CO₂ solubility, and even if the concentration is increased above this concentration, the solubility does not improve significantly. This study provided fundamental work to develop a more practical fuel by capturing CO₂ from LFG and increasing the concentration of CH₄ while reducing greenhouse gas emissions.

• Plant Journal
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• v.10 no.1
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• pp.34-39
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• 2014

Simulation works for comparing removal capabilities of acid gases contained in natural gas among several aqueous amine absorbents using commercial process simulator PROMAX(BR&E Co.) were carried out. Amine aqueous solution used in this study were 30 wt% MEA, 30 wt% DEA, 50 wt% MDEA, and 50 wt% MDEA with 3 wt% piperazine as additive. We obtained the simulated results that while MEA aqueous solution is relatively capable of more $CO_2$ gas, but DEA, MDEA, MDEA aqueous solutions with piperazine as additive are capable of more $H_2S$ gas. Also, we found that 30 wt% MDA aqueous solution is the smallest circulate rate of lean amine solution, and 50 wt% MDEA aqueous solution with 3 wt% piperazine as additive is the smallest heat duty in stripping unit. 50 wt% MDEA aqueous solution with 3 wt% piperazine as additive is found less amine circulation rate than 50 wt% MDEA due to the introduction of additive.

• Journal of the Korean Applied Science and Technology
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• v.32 no.1
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• pp.116-126
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• 2015

The present study utilized a shuttle mechanism of wet chemical absorption using MEA. In addition, industrial by-products containing a large amount of inorganic alkali substances were utilized for wet carbonization process. Chemical pretreatment of industrial by-products extracted calcium ions. ICP result of calcium ion was obtained up to 17,900 ppm(17.9%) by acidic substance. And also, In this work, 94% of recovery rate was obtained using wet MEA absorption process from $CO_2$ flow at the ambient condition. Through the liquid carbonation process, a sludge was fixed with rate of 0.175 mg of $CO_2$ per mg of sludge. It was found from XRD results that the structure of final product was composed of a calcite structure which is general structure of $CaCO_3$.

• Korean Chemical Engineering Research
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• v.47 no.6
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• pp.795-800
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• 2009

In this study, the $CO_2$ removal characteristics of the Vortex tube type absorbtion apparatus were investigated to enhance the compactness of $CO_2$ absorption process and to reduce the amount of absorbing solution of the $CO_2$ separation process. The Vortex tube with the diameter of 17 mm and the length of 250mm was introduced in the experimental apparatus to treat $20Nm^3/hr$ of $CO_2$ containing flue gas. The flue gases for experiments containing 11~13 vol% of $CO_2$ were supplied from the coal-firing CFBC power plant with 12 ton/hr of steam producing capacity. The mixed solutions of 20 wt% of MEA as base solution with the adding solutions like HMDA, AMP and KOH were used as absorbents. The experiments were executed under the various conditions like the absorbing solution concentrations in the range of 20 to 50 wt%, the flow rate of $CO_2$ containing flue gases in the range of 6 to $15Nm^3/hr$ and the flow rate of absorbing solution in the range of 1.0 to 3.0 l/min. As a results, the $CO_2$ removal efficiency of mixed absorbent of 20 wt% of MEA with HMDA was remarkable. From this study, we concluded that the efficient separation of $CO_2$ from flue gases using the features of the Vortex tube type absorbing unit for gas/liquid contact and the separation of gas/liquid be possible. But more works are needed to increase the $CO_2$ removal efficiency of Vortex tube process.

• Journal of the Korean Applied Science and Technology
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• v.29 no.1
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• pp.88-94
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• 2012

In this study, the current-voltage curves for metals were measured using cyclic voltammetry. The relationship between the electrochemical properties and surface states of metals were investigated by Scanning Electron Microscope (SEM). In cyclic voltammetry, we used a 3-electrode system for the electrochemical measurements. The measurement was conducted at the condition that consists of the first reduction from the initial potential to -1350 mV, continuous oxidation to 1650 mV, and last reduction to the initial potential. The scan rates were 50, 100, 150 and 250 mV/s. The results show the C-V characteristics of metals to be for an irreversible process, which was caused by the oxidation current from cyclic voltammogram, when monoethanolamine (MEA) was used as a corrosion inhibitor. When we used MEA as a corrosion inhibitor, the diffusion coefficient was decreased as the concentration of electrolyte was increased. In the SEM images of copper, we observed an increase of surface corrosion at the increased electrolyte concentration. Addition of $1.0{\times}10^{-3}M$ corrosion inhibitor MEA reduced the effect of corrosion prevention due to the relatively large diffusion coefficient at the electrolyte concentration of 0.1N.

• Korean Chemical Engineering Research
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• v.60 no.1
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• pp.20-24
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• 2022

In the process of long-term use of PEMFC (Proton Exchange Membrane Fuel Cells), chemical degradation of membrane electrode assembly (MEA) occurs due to corrosion of stack elements and contamination of supply gas. In this study, we investigated whether chemically degraded MEA can be recovered by acid washing. The performance was measured and compared in a PEMFC cell after contamination with iron ions and washing with an aqueous sulfuric acid solution. The performance was reduced by about 25% by 0.5 ppm iron ion contamination, and 97.1% performance recovery was possible by washing of 0.15 M sulfuric acid. The membrane resistance was increased due to iron ion contamination of the polymer membrane, and the ionic conductivity was restored by washing the iron ions from the membrane while minimizing the loss of the electrode catalyst by washing with a low-concentration sulfuric acid aqueous solution. The possibility of solving the decrease in durability caused by chemical contamination of PEMFC MEA by the acid washing was confirmed.