• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.3
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• pp.270-276
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• 2005

This study was conducted to examine whether a specific synthetic metalworking fluid (MWF), "A", in use for 10 months without replacement, displayed microbial resistance and to identify the additives associated with the control of microbial growth. Three synthetic MWF products ("A", "B", and "C") were studied every week for two months. Microbial deterioration of the fluids was assessed through evaluation by endotoxin, bacteria and fungi levels in the MWFs. In addition, formaldehyde, boron, ethanolamine, and copper levels were also studied to determine whether they influence microbial growth in water-based MWFs. Throughout the entire study in the sump where MWF "A" was used, bacteria counts were lower than 103 CFU/mL, and endotoxins never exceeded 103 EU/mL. These levels were significantly lower than levels observed in sumps badly deteriorated with microbes. Boron levels in MWF "A" ranged from 91.7 to 129.6 ppm, which was significantly higher than boron levels found in other MWF products. The total level of ethanolamine (EA) in MWF "A" ranged from 35,595 to 57,857 ppm (average 40,903 ppm), which was over ten times higher than that found in other MWFs. Monoethanolamine (MEA), diethanolamine (DEA) and triethanolamine (TEA) concentrations in MWF "A" were also significantly higher than seen in other MWFs. However, although EA and boron might improve anti-microbial performance, their abuse can pose a serious risk to workers who handle MWFs. From an industrial hygiene perspective, our study results stress that the positive synergistic effect of boron and EA in reducing microbial activity in MWF must be balanced with the potentially negative health effects of such additives. Our study also addresses the disadvantage of failing to comprehensively report MWF additives on Material Safety Data Sheets (MSDS). Future research in MWF formulation is needed to find the best level of EA and boron for achieving optimal synergistic anti-microbial effects while minimizing employee health hazards.

• Membrane Journal
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• v.22 no.1
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• pp.46-53
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• 2012

Low-temperature carbon dioxide stripping by a vacuum membrane stripping technology was studied as a substitute for the stripping process in a conventional aqueous amine process. Composite membranes with $5{\mu}m$ thickness of PDMS (polydimethylsiloxane) dense layer on a PE (polyethylene) support layer were prepared by a casting method and used as a membrane contactor for $CO_2$ stripping. Aqueous amine solutions of 30 wt% MEA (monoethanolamine) were used as absorbents. $CO_2$ flux was examined under various operating conditions by varying the vacuum pressure (60~360 mmHg (abs.)), stripping temperature ($25{\sim}80^{\circ}C$), $CO_2$ loading (0.5~0.7). $CO_2$ stripping flux increased with increasing temperature and $CO_2$ loading as well as decreasing vacuum pressure. PDMS-PE composite membrane has stability for vacuum stripping process compared with PTFE porous membrane.

• Journal of Energy Engineering
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• v.14 no.4 s.44
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• pp.219-225
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• 2005

for the removal of carbon dioxide in flue gas, which is the main cause of the global warming, chemical absorption methods were widely used for years. Alkanolamines such as MEA, AMP, MDEA are mainly used as an absorbent. In this study, cyclic amines - Piperazine, Piperidine and Cyclohelylamine are investigated to compare the chemical solubilities, absorption capacities and rate ot reaction. In conclusion, Piperazine is the most effective absorbent of $CO_2$ and ran be the excellent alternative to the former absorbents. Experiments were performed at 5, 10, 15 weight percent, 30, 40, $50^{\circ}C$, and the gas solubilities are determined by back-titration method, and using Gas Chromatography the absorption rate was compared.

• Asian Journal of Atmospheric Environment
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• v.10 no.2
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• pp.99-113
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• 2016

In order to improve the portability of basic absorbents monoethanolamine (MEA) and glycine (Gly), both were supported on microporous activated carbon (AC). Chemical modification by alkali-metal ion exchange (of Li, Na, K) was carried out on Gly-based absorbents. All supported absorbents were subjected to $CO_2$ absorption capacity (pure $CO_2$) and selectivity (indoor level) tests. Textural and chemical characterizations were carried out on test sorbents. All impregnation brought about significant reduction of specific surface area and microporosity of the adsorbent Depreciation in the textural properties was found to result to reduction in pure $CO_2$ sorption. Contrarily, low-level $CO_2$ removal capacity was enhanced as the absorbent dosage increases, resulting in supported 5 molar MEA in methanol solution. Adsorption capacities were improved from 0.016 and 0.8 in raw ACs to 1.065 mmol/g for MEA's. Surface chemistry via X-ray photoelectron spectroscopy (XPS) of the supported sorbents showed the presence of amine, pyrrole and quaternary-N. In reducing sequence of potency, pyridine, amine and pyrrolic-N were noticed to contribute significantly to $CO_2$ selective adsorption. Furthermore, the adsorption isotherm study confirms the presence of various SNGs heterogeneously distributed on AC. The adsorption mechanism of the present AC adsorbents favored Freundlich and Langmuir isotherm at lower and higher $CO_2$ concentrations respectively.

• Korean Chemical Engineering Research
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• v.49 no.2
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• pp.256-262
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• 2011

Amine can undergo irreversible reactions by $O_{2}$ and high temperature in amine scrubbing process and these phenomena are called "degradation". Degradation causes not only a loss of valuable amine, but also operational problems such as foaming, corrosion and fouling. In this study, using various chemical absorbents(MEA; monoethanolamine, AMP; 2-amino-2-methyl-1-propanol, DAM; 1,8-diamino-p-menthane), we examined the following variable. I) loading ratio of $CO_{2}$ at $50^{\circ}C$ and $120^{\circ}C$, ii) concentration variation and initial degradation rate constant of absorbent in $CO_{2}$ and $CO_{2}/O_{2}$ system, and iii) effect of degradation by $O_{2}$. The $CO_{2}$ loading of 20 wt% DAM was 400% and 270% higher than that of 20 wt% MEA and AMP at 50, respectively and was the largest the difference of $CO_{2}$ loading between absorption $(50^{\circ}C)$ and regeneration $(120^{\circ}C)$ condition. The initial degradation rate constant of 20 wt% DAM was $2.254{\times}10^{-4}cycle^{-1}$ which was slower than that of MEA $(2.761{\times}10^{-4}cycle^{-1})$ and AMP $(2.461{\times}10^{-4}cycle^{-1})$ in $CO_{2}$ system. Also, it was increased 30% by $O_{2}$ that effects on the degradation by $O_{2}$ was less than 100% increased. these degradation reactions was able to identify by formation of new peak in GC and FT-IR spectrum analysis.

• Bulletin of the Korean Chemical Society
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• v.34 no.3
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• pp.783-787
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• 2013

The separation and capture process of carbon dioxide from power plants is garnering interest as a method to reduce greenhouse gas emissions. In this study, aqueous alkanolamine solutions were studied as absorbents for $CO_2$ capture. The solubility of $CO_2$ in aqueous alkanolamine solutions was investigated with a continuous stirred reactor at 313, 333 and 353 K. Also, the heat of absorption ($-{\Delta}H_{abs}$) between the absorbent and $CO_2$ molecules was measured with a differential reaction calorimeter (DRC) at 298 K. The solubility and heat of absorption were determined at slightly higher than atmospheric pressure. The enthalpies of $CO_2$ absorption in monoethanolamine (MEA), diethanolamine (DEA), triethanolamine (TEA), and 2-amino-2-methyl-1-propanol (AMP) were 88.91, 70.44, 44.72, and 63.95, respectively. This investigation showed that the heat of absorption is directly related to the quantity of heat for absorbent regeneration, and is dependent on amine type and $CO_2$ loading.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.310-313
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• 2011

본 논문에서는 지구온난화의 주요원인 중의 하나인 이산화탄소를 포집하기 위한 새로운 흡수제를 연구하였다. 액상 흡수법에서 가장 중요한 핵심 기술요소는 성능과 경제성면에서 우수한 흡수제를 개발하는 것이다. 흡수평형장치인 VLE(Vapor-Liquid Equilibrium)장치를 사용하여 신규흡수제의 이산화탄소 흡수능을 평가하고 특성을 알아봄으로써 신 흡수제를 개발하고자 하였다. 기존 아민흡수제인 MEA(monoethanolamine), DEA(diethanolamine)와 비교한 결과 아미노산염 흡수제의 경우 MEA (1.108), DEA (1.105)의 이산화탄소 흡수능보다 0.15～0.2 (mol $CO_2$/mol absorbent) 더 높은 흡수능과 2.5～3배 더 빠른 겉보기 속도를 나타내는 것을 확인하였다. 본 연구를 통하여 개발된 아미노산염 흡수제가 경제적인 이산화탄소 포집공정을 구현할 수 있는 가능성을 확인하였다.

• Journal of Ocean Engineering and Technology
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• v.36 no.3
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• pp.168-180
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• 2022

The IMO has decided to proceed with the early introduction of EEDI Phase 3, a CO₂ emission regulation to prevent global warming. Measures to reduce CO₂ emissions for ships that can be applied immediately are required to achieve CO₂ reduction. We set six different CO₂ emission scenarios according to the type of ship and fuel, and designed a monoethanolamine-based CO₂ capture process for ships using a rate-based model of Aspen Plus v10. The simulation model using Aspen Plus was validated using pilot plant operation data. A ship inevitably tilts during operation, and the performance of a tilted column decreases as its height increases. When configuring the conventional CO₂ capture process, we considered that the required column heights were so high that performance degradation was unavoidable when the process was implemented on a ship. We applied a parallel column concept to lower the column height and to enable easy installation and operation on a ship. Simulations of the parallel column confirmed that the required column height was lowered to less than 3 TEU (7.8 m).

• Journal of Korean Society of Environmental Engineers
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• v.31 no.7
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• pp.505-514
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• 2009

Aqueous potassium salt of serine was proposed as an alternative $CO_2$ absorbent to monoethanolamine (MEA) and its $CO_2$ absorption characteristics were studied. The experiment has been conducted using screening test equipment with NDIR type gas analyzer and vapor-liquid equilibrium apparatus. $CO_2$ absorption/desorption rate and net amount of $CO_2$ absorbed in cyclic process are the criteria to assess the $CO_2$ absorption characteristics in this study. Effective $CO_2$ loading of potassium salt of serine and MEA are 0.425 and 0.230 respectively. Cyclic capacities are 0.354 and 0.298 for potassium salt of serine and MEA. The absorption rate of the potassium serinate decreased sharply at $CO_2$ loading is 0.1 and were maintained approximately at half of MEA. To enhance the absorption rate of aqueous potassium salt of serine, small quantities of rate promoters, namely piperazine and tetraethylenepentamine were blended, so that rich $CO_2$ loading were increased by 13.7% and 18.7% respectively. The rich $CO_2$ loading of potassium salt of serine was 29.2% and 35.0% higher than those of aqueous sodium and lithium salt of serine, respectively. The absorption rate of potassium salt of valine and isoleucine which have similar molecular structures to serine were lower than that of serine because of the presence of bulky side group. Precipitation phenomena during $CO_2$ absorption were discussed by the aid of literatures.

• Journal of Energy Engineering
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• v.28 no.4
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• pp.8-12
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• 2019

Thermal amine scrubbing is the most advanced CO₂ capture technique but its largescale application is hindered due to the large heat requirement during solvent regeneration step. The addition of a solid metal oxide catalysts can optimize the CO₂ desorption rate and thus minimize the energy consumption. Herein, we evaluate the solvent regeneration performance of Monoethanolamine (MEA) and Diethanolamine (DEA) solvents without and with two metal oxide catalysts (TiO₂ and V₂O₅) within a temperature range of 40-86℃. The solvent regeneration performance was evaluated in terms of CO₂ desorption rate and overall amount of CO₂ desorbed during the experiments. Both catalysts improved the solvent regeneration performance by desorbing greater amounts of CO₂ with higher CO₂ desorption rates at low temperature. Improvements of 86% and 50% in the CO₂ desorption rate were made by the catalysts for MEA and DEA solvents, respectively. The total amount of the desorbed CO₂ also improved by 17% and 13% from MEA and DEA solvents, respectively. The metal oxide catalyst-aided regeneration of amine solutions can be a new approach to minimize the heat requirement during solvent regeneration and thus can remove a primary shortfall of this technology.