연소 후 이산화탄소 포집용 흡수제의 비활성화 원인 규명

조민선,채호진,이수출,조성빈,김태영,이철호,백점인,김재창 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.2

Several materials are used to design the sorbents applied in a fast-fluidized bed process for post-combustion CO2 capture. In this study, K2CO3-based dry sorbent (KMC) was prepared by using Micro-cell C (MCC), one of the materials used to design the sorbent, and then its CO2 sorption and regeneration properties were evaluated. KMC sorbent showed a low CO2 capture capacity of 21.6 mg CO2/g sorbent, which is about 22% of the theoretical value (95.4 mg CO2/g sorbent) even at 1 cycle, and showed a low CO2 capture capacity of 13.7 mg CO2/g sorbent at 5 cycles. It was confirmed that the KMC sorbent was deactivated due to the formation of a K2Ca (CO3)2 phase, resulting from the reaction of the K2CO3 with the Ca component contained in the MCC. In order to solve the deactivation of sorbent, and KM8 sorbent was prepared by adding the process of calcining the MCC at 850 °C. The KM8 sorbent showed a high CO2 capture capacity of 95.2 mg CO2/g sorbent and excellent regeneration property. Thus, it was confirmed that the deactivation of the sorbent could be solved by adding the calcining step to remove the side reaction causing material. 연소 후 이산화탄소 포집용 고속 유동층 공정에서 사용되는 흡수제를 대량생산할 때, 흡수제 강도를 위해 여러 가지 물질을 사용한다. 본 연구에서는 흡수제 설계시 사용하는 물질 중 하나인 Micro-cell C (MCC)를 사용하여 K2CO3 기반 건식 흡수제(KMC)를 제조하였고, 흡수 및 재생 특성을 평가하였다. 흡수반응은 60 oC에서 실험하였고, 재생반응은200 oC에서 실험하였다. KMC 흡수제의 연속실험 결과, 1 cycle임에도 불구하고 이론흡수능(95.4 mg CO2/g sorbent)의 약22%인 21.6 mg CO2/g sorbent의 낮은 흡수능을 나타내었고, 5 cycle에서는 13.7 mg CO2/g sorbent의 낮은 흡수능을나타내었다. XRD 및 TG 분석결과, MCC에 함유된 Ca계 성분으로 인해 제조 및 흡수 과정에서 부반응 물질인K2Ca(CO3)2 구조가 생성됨에 따라 흡수제가 비활성화된 것을 확인하였다. 또한 흡수제 비활성화 문제를 해결하기 위해, MCC를 850 oC에서 먼저 소성하는 과정을 추가하여 흡수제(KM8)를 제조하였다. KM8 흡수제는 1 cycle에서 95.2 mg CO2/g sorbent의 높은 흡수능을 나타낼 뿐만 아니라 5 cycle 동안 우수한 재생성을 나타내었다. 따라서 소성단계를 추가함으로써 부반응 원인물질 제거방법을 통해 흡수제의 비활성화를 해결할 수 있음을 확인하였다.

석탄 화력발전소의 비산재를 이용한 건식 CO₂ 흡수제 제조 및 특성 연구

이제희(Jae Hee Lee),위정호(Jung Ho Wee) 大韓環境工學會 2013 대한환경공학회지 Vol.35 No.8

본 논문에서는 석탄화력발전소에서 배출되는 비산재의 CO₂ 건식흡수제의 첨가제 및 담체로써의 효과를 검토하였다. 이를 위해 필요에 따라 비산재와 CO₂ 포집 유효 성분인 NaOH, CaO 및 물을 조합하여 여러 종류의 흡수제를 제조한 후, CO₂흡수 실험을 포함한 흡수제의 특성 분석을 수행하였다. 그 결과, 조건에 따라 흡수율과 흡수 온도, 속도 및 탈기 현상 등, 비산재 투입에 의한 다양한 효과를 확인할 수 있었고 NaOH, CaO 및 비산재와 물이 첨가되어 제조된 흡수제에서 비산재 효과가 가장 크게 나타났다. 550℃에서 본 흡수제의 CO₂ 흡수율은 비산재가 첨가되지 않은 흡수제에 비해 35.6% 높았고 흡수종료 후, CO₂ 탈기 현상도 관측되었다. 이는 비산재 첨가 때문으로 흡수제 내, 유효 성분들이 비산재 주변으로 분산도가 높고 상대적으로 미세한 입자로 존재하였다. 또한 비산재의 담체 역할이 확인되며 NaOH로 인해 흡수제 내 포졸란 반응이 억제되기 때문이다. 탈기 현상도 비산재 첨가로 인한 현상으로 NaOH, CaO가 비산재와 물리, 화학적 결합을 형성하여 Na와 Ca에 포집되어 있는 CO₂의 결합력이 약화되기 때문으로 판단된다. This paper investigates the effect of coal-fired fly ash on dry CO₂ sorbents as the supports and additives. For this purpose, various kinds of dry sorbent were manufactured by mixing fly-ash, the primary CO₂ absorption components (NaOH and CaO) and water with their different combination. Thereafter, their CO₂ absorption performance and the property were analyzed. As a result, variation of absorption efficiency and temperature as well as CO₂ desorption of the sorbents are confirmed, which may be primarily ascribed to fly-ash addition to the sorbents. Particularly, fly-ash effect is strongly measured in the sorbent manufactured by mixing all four components (named WNCF sorbents). Absorption efficiency of WNCF sorbents at 550℃ is 35.6% higher than that of fly- ash free sorbent and desorption is solely observed in WNCF sorbents. Fly-ash in WNCF sorbents leads to increase the dispersity of CO₂ absorption components and decrease their particle size in the sorbents. In addition, fly-ash is used as the supports and pozzolanic reaction is hindered by NaOH in WNCF sorbent. Furthermore, CO₂ desorption from the sorbents may be due to fly-ash. The interaction between fly-ash and CO₂ absorption components substantially attenuate the strength between captured CO₂ in CaO and NaOH.

Performance analysis of K-based KEP-CO2P1 solid sorbents in a bench-scale continuous dry-sorbent CO2 capture process

ChangkeunYi,Young Cheol Park,Sung-Ho Jo,Seung Yong Lee,Jong-Ho Moon,Chong Kul Ryu,Joong Beom Lee 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.1

Korea Institute of Energy Research (KIER) and Korea Electric Power Corporation Research Institute (KEPCORI) have been developing a CO2 capture technology using dry sorbents. In this study, KEP-CO2P1, a potassium-based dry sorbent manufactured by a spray-drying method, was used. We employed a bench-scale dry-sorbent CO2 capture fluidized-bed process capable of capturing 0.5 ton CO2/day at most. We investigated the sorbent performance in continuous operation mode with solid circulation between a fast fluidized-bed-type carbonator and a bubbling fluidizedbed- type regenerator. We used a slip stream of a real flue gas from 2MWe coal-fired circulating fluidized-bed (CFB) power facilities installed at KIER. Throughout more than 50 hours of continuous operation, the temperature of the carbonator was maintained around 70-80 oC using a jacket-type heat exchanger, while that of the regenerator was kept above 180 oC using an electric furnace. The differential pressure of both the carbonator and regenerator was maintained at a stable level. The maximum CO2 removal was greater than 90%, and the average CO2 removal was about 83% during 50 hours of continuous operation.

Synthesis of dry sorbents for carbon dioxide capture using coal fly ash and its performance

Lee, J.,Han, S.J.,Wee, J.H. Applied Science Publishers 2014 APPLIED ENERGY Vol.131 No.-

The present paper investigates the application of raw coal fly ash (FA) to dry-based CO<SUB>2</SUB> fixation. Dry sorbents are manufactured by mixing FA, NaOH, CaO and a small amount of water and their absorption behavior, performance, regeneration and leaching efficiency are analyzed. The CO<SUB>2</SUB> absorption efficiency (AE) of FA-added sorbent (WNCF) is higher than that of FA-free sorbents (WNC) and its absorption behavior is improved. In addition, CO<SUB>2</SUB> desorption from carbonated WNCF (CWNCF) occurs at 100<SUP>o</SUP>C lower than that from carbonated WNC (CWNC) and its desorption efficiency is 16.5% point higher than that of CWNC, due to the FA addition to the sorbent. However, the AE of regenerated CWNCF is substantially lower than that of fresh WNCF, which indicates that CWNCF cannot easily be regenerated by simple desorption increasing temperature. This is ascribed to the effect of the added FA and water in contributing to the production of Ca- and Na-based carbonated materials that cannot readily be regenerated during the carbonation. Some of the inherent K and Ca components present in the raw FA participate in the carbonation of WNCF, and Cr is co-precipitated during WNCF carbonation to become a stabilized material.

건식 흡수제를 이용한 발전소배가스의 CO2 회수공정 경제성분석

심병철 ( Byung Chul Shin ),곽현 ( Hyun Kwak ),이광민 ( Kwang Min Lee ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.4

We studied the economic evaluations on Korea Institute of Energy Research (KIER)`s CO2 capture process using dry sorbents, and compared the results with those of comparable technologies. Capital and operating costs of the CO2 capture system for 500 MW coal fired power plant were estimated to determine the economic feasibility. LCOE (Levelized Cost of Energy) and CO2 capture cost appeared 32.46$/MWh and 28.15$/tonCO2, 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 CO2 capture system was 15%, NPV was calculated 6,631,000$, and PBP was 5.93 years at $50/tCO2 of CER price. Consequently, this process can compete with other comparative processes using dry sorbents.

유동층 공정에서 Dry Sorbent의 마모 및 CO₂ 흡착특성

이상섭(Lee Sang Seob),우광제(U Gwang Je),문길호(Mun Gil Ho),오광중(O Gwang Jung) 大韓環境工學會 2003 대한환경공학회지 Vol.25 No.11

Thermal design of heat-exchangeable reactors using a dry-sorbent CO₂ capture multi-step process

Moon, Hokyu,Yoo, Hoanju,Seo, Hwimin,Park, Yong-Ki,Cho, Hyung Hee Elsevier 2015 ENERGY Vol.84 No.-

<P><B>Abstract</B></P> <P>The present study proposes a multi-stage CO<SUB>2</SUB> capture process that incorporates heat-exchangeable fluidized-bed reactors. For continuous multi-stage heat exchange, three dry regenerable sorbents: K<SUB>2</SUB>CO<SUB>3</SUB>, MgO, and CaO, were used to create a three-stage temperature-dependent reaction chain for CO<SUB>2</SUB> capture, corresponding to low (50–150 °C), middle (350–650 °C), and high (750–900 °C) temperature stages, respectively. Heat from carbonation in the high and middle temperature stages was used for regeneration for the middle and low temperature stages. The feasibility of this process is depending on the heat-transfer performance of the heat-exchangeable fluidized bed reactors as the focus of this study. The three-stage CO<SUB>2</SUB> capture process for a 60 Nm<SUP>3</SUP>/h CO<SUB>2</SUB> flow rate required a reactor area of 0.129 and 0.130 m<SUP>2</SUP> for heat exchange between the mid-temperature carbonation and low-temperature regeneration stages and between the high-temperature carbonation and mid-temperature regeneration stages, respectively. The reactor diameter was selected to provide dense fluidization conditions for each bed with respect to the desired flow rate. The flow characteristics and energy balance of the reactors were confirmed using computational fluid dynamics and thermodynamic analysis, respectively.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CO<SUB>2</SUB> capture process is proposed using a multi-stage process. </LI> <LI> Reactor design is conducted considering heat exchangeable scheme. </LI> <LI> Reactor surface is designed by heat transfer characteristics of fluidized bed. </LI> </UL> </P>

Energy exchangeable multi-stage dry sorbent CO₂ capture process

박용기,서휘민,최원춘,강나영,박선영,민다영,김혜미 한국공업화학회 2014 한국공업화학회 연구논문 초록집 Vol.2014 No.1

A dry sorbent CO₂ capture process was designed to reduce the thermal energy consumption. The process utilize heat of absorption for heat of regeneration by consisting 3 stage process, and it can reduce the total thermal energy demand of a single stage capture process by more than 50%. The concept was realized as a lab-scale facility that can deal with CO₂ containing gas mixture with a flow rate of 60N㎥/h. The facility was designed so as to make inter-stage heat exchange and intra-stage heat exchange possible, and to measure the heat exchange rate accurately. The process needs 3 kinds of sorbents that work at the 3 different temperature stages. Three spherical sorbents suitable for fluidized beds have been developed. Development results of the facility and the sorbents for the energy exchangeable dry sorbent CO₂ capture process will be presented, and the operation results of the 60N㎥/h facility will also be disclosed.

A study on vortex generators to improve the mixing rate in the dry sorbent injection process of the flue gas desulfurization system

Jin Do Chung,Jang Woo Kim,Young Moon Park 한국화학공학회 2010 Korean Journal of Chemical Engineering Vol.27 No.1

The aim of this study is to improve mixing rate of dry sorbent injection technology (DSI). A CFD (Computational Fluid Dynamics) code is used to predict the sorbent dispersion rate, pressure drop and turbulent kinetic energy of mixing particles and gas flow for three different vortex generators, which have been designed for the inside of the duct. After analyzing simulated results, it was shown that a similar trend of change in the dispersion rate in three different vortex generators had taken place and that the dispersion rate curve could reach over 80% by applying the lobed-plate and guide-vane(B) vortex generators. The lowest pressure drop was obtained when a lobed-plate was installed,whereas the highest pressure drop occurred when a guide-vane(A) was installed. The turbulent kinetic energy is nearly always stable when a lobed-plate is applied, but increases very quickly after passing through a guide-vane and then slowly decreases when a guide-vane(B) is applied. The situation for in the case of guide-vane(A) is somewhat more complicated.

Regenerable potassium-based alumina sorbents prepared by CO2 thermal treatment for post-combustion carbon dioxide capture

Jae Chang Kim,Seong Bin Jo,이수출,Ho Jin Chae,Min Sun Cho,Joong Beom Lee,Jeom-In Baek 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.11

Potassium carbonate supported on alumina is used as a solid sorbent for CO2 capture at low temperatures. However, its CO2 capture capacity decreases immediately after the first cycle. This regeneration problem is due to the formation of the by-product [KAl(CO3)(OH)2] during CO2 sorption. To overcome this problem, a new regenerable potassium-based sorbent was fabricated by CO2 thermal treatment of sorbents prepared by the impregnation of δ-alumina with K2CO3 in the presence of 10 vol% CO2 and 10 vol% H2O. The CO2 capture capacities of the new regenerable sorbents were maintained over multiple CO2 sorption tests. These results can be explained by the fact that the sorbent prepared by CO2 thermal treatment did not form any by-product during CO2 sorption. Based on these results, we suggest that the regeneration properties of potassium-based sorbents using δ-alumina could be significantly improved by the use of the CO2 thermal treatment developed in this study.