• Transactions of the Korean hydrogen and new energy society
• /
• v.24 no.4
• /
• pp.334-339
• /
• 2013

In this study, as a candidate of the carbon dioxide ($CO_2$) absorbents, the mixture solution of polyethylene glycol dimethyl ether (PEGDME) and tetrahydrofuran (THF) were investigated. $CO_2$ absorption rate was measured by using high pressure $CO_2$ screening equipment in the range of 1 - 10wt% THF. Absorption capacity of the mixture solution was also estimated. Based on the results, we found that mixture solution containing THF had higher absorption rate and $CO_2$ loading capacity compared to PEGDME at $25^{\circ}C$.

• Journal of the Korea Concrete Institute
• /
• v.21 no.1
• /
• pp.85-92
• /
• 2009

A concrete is considered unfriendly-environmental material because it uses cement which emits much $CO_2$ during producing process. However, a concrete absorbs $CO_2$ through carbonation process during service life. In this paper how much concrete absorbs $CO_2$ through carbonation was calculated using 1) concentration of carbonatable substances in concrete, 2) carbonated volume of concrete, 3) molecular weight of $CO_2$ based on references and the method was proposed. $CO_2$ emission from producing $1m^3$ concrete was calculated based on $CO_2$ emission datum of materials used in concrete. From using these methods that calculate $CO_2$ emission and absorption of concrete, assessment of $CO_2$ emission-absorption against a real apartment was conducted by subtracting absorption $CO_2$ according to service life from $CO_2$ emission in the process of making concrete. As a result, a ratio of absorption over emission of $CO_2$ through concrete carbonation according to service life 40, 60, 80 years was assessed about 3.65, 4.47, 5.18%. An objective of this study is to propose how to calculate emission - absorption of $CO_2$ from producing and using concrete. Although the result value, emission - absorption of $CO_2$, is 5.18% very low when the service life of an apartment is 80years, the value can be improved by reducing emission from using blended cement such as blast furnace slag or increasing replacement ratio of cement and increasing carbonated volume of concrete from expanding service life of a building. This study may be useful when $CO_2$ emission - absorption of concrete is evaluated in the further study.

• Korean Chemical Engineering Research
• /
• v.61 no.4
• /
• pp.555-560
• /
• 2023

Conventional aqueous amine-based CO₂ capture has a problem in that a large amount of renewable energy is required for CO₂ stripping and solvent regeneration in its industrial applications. This work proposes a water-lean absorbent that can reduce regeneration energy by lowering the water content in the absorbent with high absorption capacity for CO₂. To this purpose, this water-lean solvent introduced NMP (N-methyl-2-pyrrolidone), which has a higher physical solubility in CO₂ and a low specific heat capacity comparing to water, along with 3-methylaminopropylamine (MAPA), a diamine, into the absorbent. The circulating absorption capacity and absorption rate for CO₂ of this water-lean solvent were measured using a packed tower. When NMP was added to the absorbent, the absorption rate was improved. In the case of the absorbent containing 2.5M MAPA was used, the maximum circulating absorption capacity was obtained when 10 wt% of NMP was included in absorbent. The overall mass transfer coefficient increased as the concentration of NMP increased. However, at loading values higher than 0.5, the increment in mass transfer coefficient decreased as the concentration of NMP increased. When the lean loading value is low, the mass transfer resistance due to viscosity of the absorbent is low, so the overall mass transfer coefficient increases with the addition of NMP. However, as the lean loading value increases, the viscosity of the absorbent increases, and the diffusivity of CO₂ and MAPA decreases, resulting in sharply decreasing of the overall mass transfer coefficient.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.2
• /
• pp.165-172
• /
• 2014

Experiments were conducted to identify basic characteristics of $CO_2$ capture using a spray tower with a single nozzle. Results were evaluated in terms of $CO_2$ saturation which is the main determining factor of regeneration energy, and capture efficiency under various operating conditions. Changes in the capture efficiency under various conditions are well expressed as a monotone increasing function of the relative solvent $(NH_3):CO_2$ flow rate. Although changes in $CO_2$ saturation are also well described as a function of the $NH_3/CO_2$ flow rate ratio, these are expressed as a monotone decreasing function, in contrast with the increasing function of $CO_2$ efficiency. In recent research on the relationship between $CO_2$ saturation and capture efficiency, $CO_2$ saturation was found to decrease when capture efficiency increased. In conclusion, the results show that the amount of solvent used for achieving high capture efficiencies is excessive, as is the amount of regeneration energy needed.

• Korean Chemical Engineering Research
• /
• v.55 no.3
• /
• pp.419-425
• /
• 2017

In this study, the performance characteristics of the K-based sorbents (KEP-CO2P2, KEPCO RI, Korea) has been studied in relation with the heat exchanger structure and shape in a mixing zone of the carbonator in the bench-scale dry $CO_2$ capture process. Two types of heat exchangers (different structure and shape) were used in the carbonator as CASE 1 and CASE 2, in which the experiment has been continuously performed under the same operating conditions. During the continuous operation, working temperature of carbonator was 75 to $80^{\circ}C$, that of regenerator was 190 to $200^{\circ}C$, and $CO_2$ inlet concentration of the feed gas was 12 to 14 vol%. Especially, to compare the dynamic sorption capacity of sorbents, the differential pressure of the mixing zone in the carbonator was maintained around 400 to 500 mm $H_2O$. Also, solid samples from the carbonator and the regenerator were collected and weight variation of those samples was evaluated by TGA. The $CO_2$ removal efficiency and the dynamic sorption capacity were 64.3% and 2.40 wt%, respectively for CASE 1 while they were 81.0% and 4.66 wt%, respectively for CASE 2. Also, the dynamic sorption capacity of the sorbent in CASE 1 and CASE 2 was 2.51 wt% and 4.89 wt%, respectively, based on the weight loss of the TGA measurement results. Therefore, It was concluded that there could be a difference in the performance characteristics of the same sorbents according to the structure and type of heat exchanger inserted in the carbonator under the same operating conditions.

• Korean Chemical Engineering Research
• /
• v.50 no.4
• /
• pp.646-653
• /
• 2012

We studied the economic evaluations on Korea Institute of Energy Research (KIER)'s $CO_2$ capture process using dry sorbents, and compared the results with those of comparable technologies. Capital and operating costs of the $CO_2$ capture system for 500 MW coal fired power plant were estimated to determine the economic feasibility. LCOE (Levelized Cost of Energy) and $CO_2$ capture cost appeared 32.46$/MWh and 28.15$/ton$CO_2$, respectively. The internal rate of return (IRR), the net present values (NPV), and the payback period (PBP), were calculated by assuming several variables. As the result of calculation, IRR of KIER's $CO_2$ capture system was 15%, NPV was calculated 6,631,000$, and PBP was 5.93 years at $50/t$CO_2$ of CER price. Consequently, this process can compete with other comparative processes using dry sorbents.

• Korean Chemical Engineering Research
• /
• v.53 no.1
• /
• pp.57-63
• /
• 2015

Absorption characteristics of 2-methylpiperidine (2MPD), 3-methylpiperidine (3MPD) and 4-methylpiperidine (4MPD) absorbents were studied by a vapor-liquid equilibrium (VLE) apparatus and a differential reaction calorimeter (DRC). Using a VLE apparatus, the $CO_2$ loading capacity of each absorbent was estimated. After reaching the absorption equilibrium, nuclear magnetic resonance spectroscopy (NMR) had been conducted to characterize the species distribution of the ($H_2O$-piperidine-$CO_2$) system. Using a DRC, the reaction of heat was confirmed in accordance with the absorption capacity. The unique characteristics of 2MPD, 3MPD and 4MPD absorbents appeared by the position of methyl group. The 2MPD possessing the methyl group at the ortho position showed its hindrance effect during the absorption process; however, piperidine derivatives possessing the meta position and para position did not show its characteristics in $H_2O$-piperidine-$CO_2$ system.

• Clean Technology
• /
• v.19 no.2
• /
• pp.165-172
• /
• 2013

In this study, the hydrogen chloride removal using K-based dry sorbents ($K_2CO_3/Al_2O_3$, KEPRI, Korea) was studied with varying the pressure in a fixed bed reactor (15 cm tall bed with 0.5 cm I.d.). Working temperature was $400^{\circ}C$ and feed gas concentration was 750 ppm (HCl vol%, $N_2$ balance). The chloride sorption capacity of sorbent increases with increasing pressure (1, 5, 10, 15 and 20 bar). Also, after forming KCl crystal by reaction with $K_2CO_3$ and HCl, owing to the strong bonding energy, sorbent regeneration was practically impossible. Its optical, physical and chemical characterizations were evaluated by SEM, EDAX, BET, TGA and XRD. At $400^{\circ}C$ and 20 bar condition, working condition for the dehalogenation process after gasification, K-based dry sorbent showed high HCl sorption capacity and HCl/$N_2$ separation performances comparing with Ca-based and Mg-based dry sorbents.

• Korean Journal of Environment and Ecology
• /
• v.13 no.3
• /
• pp.254-260
• /
• 1999

본 연구는 수목피도가 상이한 춘천시 내 두 주거지구를 선정하여 수목식재가 주요 온실가스인 대기 CO_2$의 직접적 간접적 흡수에 영향하는 효과를 비교 분석하였다 수목의 탄소저장량은 수목 피도가 약 10%인 제 1지구에서 단독 주택의 호당 평균 72kg 소목피도가 약 20%인 제 2지구에서 244kg 이었다 수목피도가 제 1지구보다 10% 차이로 더 높은 제 2지구에서 그 탄소저장량은 3배 더 많았다. 수목의 연간 직간접적 탄소흡수량은 제1지구에서 호당 평균 59kg/yr이었고 제 2지구에서는 그보다 약 2배 더 많은 110kg/yr 이었다. 연간 총흡수량중 간접적 흡수량은 연구지구에 따라 70-80%를 차지하여 직접적 흡수량보다 훨씬 많았다. 연구결과는 주거지 내 적극적인 수목식재가 대기 탄소농도를 저감하는 중요한 역할을 증진할 수 있음을 시사하였다.

• Journal of the Korea Institute of Building Construction
• /
• v.15 no.1
• /
• pp.17-23
• /
• 2015

In this research, the $CO_2$ absorption performance of mortar was investigated. The level of $CO_2$ absorption in mortar with various binders including cement and nonsintered cement was examined. As a result for the mortar with photosynthetic bacteria, the compressive strength was similar to the one without the bacteria at early age but decreased at the age of 28 days. However, for the $CO_2$ absorption, with photosynthetic, the performance of the mortar with OPC, and nonsintered cement deceased to 21%(234 ppm) and 19.7%(243 ppm) respectively after 12 hours age.