Dynamic modeling of a dual fluidized-bed system with the circulation of dry sorbent for CO₂ capture

Ju, Youngsan,Lee, Chang-Ha Elsevier 2019 APPLIED ENERGY Vol.241 No.-

<P><B>Abstract</B></P> <P>In CO<SUB>2</SUB> capture processes with the circulation of dry sorbents, the regeneration energy as well as the capture efficiency are the key factors determining the overall energy efficiency of the CO<SUB>2</SUB> capture. In an aspect of repeated circulation and regeneration of a sorbent, a dynamic model for a dual fluidized-bed system was developed, which includes a fast fluidized-bed carbonator and a bubbling fluidized-bed regenerator. A potassium carbonate-based sorbent for CO<SUB>2</SUB> capture was applied in the fluidized-bed system and rigorous kinetic models for the carbonation and regeneration reactions were adopted. The validity of the developed model was confirmed by accurately predicting the experimental results from the dual fluidized-bed system at various operating conditions. The CO<SUB>2</SUB> removal performance was found to slightly deteriorate from 52.8 to 51.9% during continuous cyclic operation when the regeneration was carried out under a nitrogen atmosphere at 150 °C. However, when CO<SUB>2</SUB> gas was used for the regeneration under the same conditions, the capture performance dropped to 18.6% owing to partial regeneration of the sorbent. A case study for the regeneration condition was conducted using a CO<SUB>2</SUB>-rich gas to find the effective regeneration condition. The regeneration conversion under CO<SUB>2</SUB> atmosphere could be improved by increasing the regeneration gas velocity and regeneration temperature. At a regeneration temperature of 160 °C, the capture performance was found to be 73.2%, with the energy required to capture one mole of CO<SUB>2</SUB> being 234.8 kJ/mol-CO<SUB>2</SUB>. To reduce the energy requirement to less than 200 kJ/mol-CO<SUB>2</SUB> in the dual fluidized-bed system, a granulated sorbent, satisfying the physical and chemical stability for fluidized-bed operation, should be developed for the regeneration below 145 °C with the same working capacity (0.46 mol/kg-solid). Alternatively, the working capacity should be improved by 30% at the regeneration temperature of 160 °C. The developed model can be further used for improving capture performance and energy efficiency.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A dual fluidized-bed system using K<SUB>2</SUB>CO<SUB>3</SUB>-based sorbent for CO<SUB>2</SUB> capture was modeled. </LI> <LI> The model predicted the capture efficiencies well at various operating conditions. </LI> <LI> Dynamic behaviors of fast and bubbling fluidized-beds using sorbents were analyzed. </LI> <LI> An energy-efficient regeneration condition under CO<SUB>2</SUB>-rich flow was evaluated. </LI> </UL> </P>

Effect of a Li₂SiO₃ phase in lithium silicate-based sorbents for CO₂ capture at high temperatures

Kwon, Yong Mok,Chae, Ho Jin,Cho, Min Sun,Park, Yong Ki,Seo, Hwi Min,Lee, Soo Chool,Kim, Jae Chang Elsevier 2019 Separation and purification technology Vol.214 No.-

<P><B>Abstract</B></P> <P>The Li<SUB>4</SUB>SiO<SUB>4</SUB> sorbent is considered one of the most promising CO<SUB>2</SUB> acceptor materials at high temperatures, but it has the disadvantage of poor CO<SUB>2</SUB> capture performance due to aggregation. In this study, a novel lithium silicate-based sorbent containing both Li<SUB>4</SUB>SiO<SUB>4</SUB> phase and Li<SUB>2</SUB>SiO<SUB>3</SUB> phase was developed to overcome the decrease of CO<SUB>2</SUB> capture capacity of the sorbent for CO<SUB>2</SUB> capture in the high temperature range of 550–700 °C. This sorbent was simply prepared by physical mixing of Li<SUB>2</SUB>CO<SUB>3</SUB> and SiO<SUB>2</SUB> (Ludox®) in a 1.8:1 M ratio. The effect of the developed lithium silicate-based sorbent on CO<SUB>2</SUB> capture was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and temperature-programmed desorption (TPD) analysis. The novel lithium silicate-based sorbent exhibited a high CO<SUB>2</SUB> capture capacity (∼250 mg CO<SUB>2</SUB>/g sorbent) during multiple cycles at a regeneration temperature of 700 °C. In addition, we found that the CO<SUB>2</SUB> capture performance was affected by Li<SUB>2</SUB>SiO<SUB>3</SUB> phase in the lithium silicate-based sorbents. This is because the Li<SUB>2</SUB>SiO<SUB>3</SUB> in the sorbent helps prevent growth of particle size and aggregation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The sorbent containing Li<SUB>2</SUB>SiO<SUB>3</SUB> and Li<SUB>4</SUB>SiO<SUB>4</SUB> was developed for CO<SUB>2</SUB> capture. </LI> <LI> The sorbent was prepared by mixing 1.8 mol of Li<SUB>2</SUB>CO<SUB>3</SUB> with colloidal silica. </LI> <LI> The Li<SUB>2</SUB>SiO<SUB>3</SUB> phase was an inert material for CO<SUB>2</SUB> capture. </LI> <LI> The Li<SUB>2</SUB>SiO<SUB>3</SUB> in the sorbent plays an important role in improving the performance. </LI> </UL> </P>

분리막을 이용한 공기 중 이산화탄소 제거 기술

유승연,박호범 한국막학회 2020 멤브레인 Vol.30 No.3

As the demand for fossil fuels continues to increase worldwide, carbon dioxide (CO2) concentration in the air has increased over the centuries. The way to reduce CO2 emissions to the atmosphere, carbon capture and sequestration (CCS) technology have been developed that can be applied to power plants and factories, which are primary emission sources. According to the climate change mitigation policy, direct air capture (DAC) in air, referred to as “negative emission” technology, has a low CO2 concentration of 0.04%, so it is focused on adsorbent research, unlike conventional CCS technology. In the DAC field, chemical adsorbents using CO2 absorption, solid absorbents, amine-functionalized materials, and ion exchange resins have been studied. Since the absorbent-based technology requires a high-temperature heat treatment process according to the absorbent regeneration, the membrane-based CO2 capture system has a great potential Membrane-based system is also expected for indoor CO2 ventilation systems and immediate CO2 supply to smart farming systems. CO2 capture efficiency should be improved through efficient process design and material performance improvement. 전 세계 화석 연료 사용이 지속적으로 증가함에 따라 공기 중 이산화탄소(CO2) 농도가 수 세기에 걸쳐 증가하고있다. 대기로의 CO2 배출을 줄이기 위한 방법으로, 주요 배출원인 발전소와 공장에 적용할 수 있는 이산화탄소 포집 및 저장(carbon capture and sequestration, CCS) 기술이 개발되고 있다. 기후 변화 완화 정책에 따라 negative emission 기술로 언급되는 공기 중 CO2 직접 포집 기술(direct air capture, DAC)은 CO2 농도가 0.04%로 매우 낮기 때문에 기존의 CCS 기술에 적용된 기술과 달리 흡착제를 이용한 저농도 CO2 포집 연구에 집중되어 있다. DAC 분야는 주로 CO2의 흡착을 이용한 습식 흡착제, 건식 흡착제, 아민 기능화된 소재, 이온교환 수지 등이 연구되었다. 흡착제 기반 기술은 흡착제 재생에 따른 고온 열처리 공정이 필요하기 때문에 추가적인 에너지 소모가 없는 분리막 기반의 공기 중 CO2 포집 기술의 잠재력이 크다. 분리막은특히 실내 공기 CO2 저감 환기 시스템 및 실내용 스마트팜(smart farm) 시스템의 연속적인 CO2 공급에 사용될 수 있을 것으로 기대된다. CO2 처리 기술은 기후 변화를 완화하기 위한 수단으로 개발이 지속되어야 하며 효율적인 공정 설계와 소재 성능 향상을 통해 공기 중 CO2 포집의 효율을 높일 수 있을 것이다.

수소생산 공정에서의 CO2 배출처 및 유효포집기술 분석

우경택,김봉규,소영석,백문석,박승수,정혜진 한국가스학회 2023 한국가스학회지 Vol.27 No.3

Energy consumption is increased by rapid industrialization. As a result, climate change is accelerating due to the increase in CO2 concentration in the atmosphere. Therefore, a shift in the energy paradigm is required. Hydrogen is in the spotlight as a part of that. Currently 95% of hydrogen is fossil fuel-based reforming hydrogen which is accompanied by CO2 emissions. This is called gray hydrogen, if the CO2 is captured and emission of CO2 is reduced, it can be converted into blue hydrogen. There are 3 technologies to capture CO2: absorption, adsorption and membrane technology. In order to select CO2 capture technology, the analysis of the exhaust gas should be carried out. The concentration of CO2 in the flue gas from the hydrogen production process is higher than 20%if water is removed as well as the emission scale is classified as small and medium. So, the application of the membrane technology is more advantageous than the absorption. In addition, if LNG cold energy can be used for low temperature CO2 capture system, the CO2/N2 selectivity of the membrane is higher than room temperature CO2 capture and enabling an efficient CO2 capture process. In this study, we will analyze the flue gas from hydrogen production process and discuss suitable CO2 capture technology for it.

The effect of CO_2 or steam partial pressure in the regeneration of solid sorbents on the CO_2 capture efficiency in the two-interconnected bubbling fluidized-beds system

Ki-Chan Kim,이창근,Young Cheol Park,Sung-Ho Jo 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.10

The effect of CO_2 or steam partial pressure in the regeneration of CO_2 solid sorbents was studied in the two-interconnected bubbling fluidized-beds system. Potassium-based dry solid sorbents, which consisted of 35 wt%K_2CO_3 for CO_2 sorption and 65 wt% supporters for mechanical strength, were used. To investigate the CO_2 capture efficiency of the regenerated sorbent after the saturated sorbent was regenerated according to the CO_2 or steam partial pressure in the regeneration, the mole percentage of CO_2 in the regeneration gas was varied from 0 to 50 vol% with N2 balance and that of steam was varied from 0 to 100 vol% with N_2 balance, respectively. The CO_2 capture efficiency for each experimental condition was investigated for one hour steady-state operation with continuous solid circulation between a carbonator and a regenerator. The CO_2 capture efficiency decreased as the partial pressure of CO_2 in the fluidization gas of the regenerator increased, while it increased as that of steam increased. When 100 vol% of steam was used as the fluidization gas of the regenerator, the CO_2 capture efficiency reached up to 97% and the recovered CO_2concentration in the regenerator was around 95 vol%. Those results were verified during 10-hour continuous experiment.

신 흡수제(KoSol-5)를 적용한 0.1 MW급 Test Bed CO2 포집 성능시험

이정현 ( Junghyun Lee ),김범주 ( Beom Ju Kim ),신수현 ( Su Hyun Shin ),곽노상 ( No Sang Kwak ),이동욱 ( Dong Woog Lee ),이지현 ( Ji Hyun Lee ),심재구 ( Jae Goo Shim ) 한국공업화학회 2016 공업화학 Vol.27 No.4

한전 전력연구원에서 개발한 고효율 아민계 습식 CO2 흡수제(KoSol-5)를 적용하여 0.1 MW급 Test Bed CO2 포집 성능시험을 수행하였다. 500 MW급 석탄화력발전소에서 발생되는 연소 배가스를 적용하여 하루 2톤의 CO2를 처리할 수있는 연소 후 CO2 포집기술의 성능을 확인하였으며 또한 국내에서는 유일하게 재생에너지 소비량을 실험적으로 측정함으로써 KoSol-5 흡수제의 성능에 대한 신뢰성 있는 데이터를 제시하고자 하였다. 그리고 주요 공정변수 운전 및 흡수탑 인터쿨링 효율 향상에 따른 에너지 저감 효과를 테스트하였다. 흡수탑에서의 CO2 제거율은 국제에너지기구산하 온실가스 프로그램(IEA-GHG)에서 제시하는 CO2 포집기술 성능평가 기준치(CO2 제거율: 90%)를 안정적으로 유지하였다. 또한 흡수제(KoSol-5)의 재생을 위한 스팀 사용량(재생에너지)은 2.95 GJ/tonCO2가 소비되는 것으로 산출되었는데 이는 기존 상용 흡수제(MEA, Monoethanol amine)의 평균 재생에너지 수준(약 4.0 GJ/tonCO2) 대비 약 26% 저감된 수치이다. 본 연구를 통해 한전 전력연구원에서 개발한 KoSol-5 흡수제 및 CO2 포집 공정의 우수한 CO2 포집 성능을 확인할 수 있었고, 향후 본 연구에서 성능이 확인된 고효율 흡수제(KoSol-5)를 실증급 CO2 포집플랜트에 적용할 경우 CO2 포집비용을 크게 낮출 수 있을 것으로 기대된다. The absorption efficiency of amine CO2 absorbent (KoSol-5) developed by KEPCO research institute was evaluated using a 0.1 MW test bed. The performance of post-combustion technology to capture two tons of CO2 per day from a slipstream of the flue gas from a 500 MW coal-fired power station was first confirmed in Korea. Also the analysis of the absorbent regeneration energy was conducted to suggest the reliable data for the KoSol-5 absorbent performance. And we tested energy reduction effects by improving the absorption tower inter-cooling system. Overall results showed that the CO2 removal rate met the technical guideline (CO2 removal rate : 90%) suggested by IEA-GHG. Also the regeneration energy of the KoSol-5 showed about 3.05 GJ/tonCO2 which was about 25% reduction in the regeneration energy compared to that of using the commercial absorbent MEA (Monoethanolamine). Based on current experiments, the KoSol-5 absorbent showed high efficiency for CO2 capture. It is expected that the application of KoSol-5 to commercial scale CO2 capture plants could dramatically reduce CO2 capture costs.

국내 초임계 석탄화력발전소에 연소 후 CO2 포집공정 설치 시 성능 및 경제성 평가

이지현 ( Ji Hyun Lee ),곽노상 ( No Sang Kwak ),이인영 ( In Young Lee ),장경룡 ( Kyung Ryoung Jang ),심재구 ( Jae Goo Shim ) 한국화학공학회 2012 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.50 No.2

In this study, Economic analysis of supercritical coal-fired power plant with CO2 capture process was performed. For this purpose, chemical absorption method using amine solvent, which is commercially available and most suitable for existing thermal power plant, was studied. For the evaluation of the economic analysis of coal-fired power plant with post-combustion CO2 capture process in Korea, energy penalty after CO2 capture was calculated using the power equivalent factor suggested by Bolland et al. And the overnight cost of power plant (or cost of plant construction) and the operation cost reported by the IEA (International Energy Agency) were used. Based on chemical absorption method using a amine solvent and 3.31 GJ/tonCO2 as a regeneration energy in the stripper, the net power efficiency was reduced from 41.0% (without CO2 capture) to 31.6% (with CO2 capture) and the levelized cost of electricity was increased from 45.5 USD/MWh (Reference case, without CO2 capture) to 73.9 USD/MWh (With CO2 capture) and the cost of CO2 avoided was estimated as 41.3 USD/tonCO2.

신 흡수제(KoSol-5)를 적용한 0.1 MW급 Test Bed CO₂ 포집 성능시험

이정현,김범주,신수현,곽노상,이동욱,이지현,심재구,Lee, Junghyun,Kim, Beom-Ju,Shin, Su Hyun,kwak, No-Sang,Lee, Dong Woog,Lee, Ji Hyun,Shim, Jae-Goo 한국공업화학회 2016 공업화학 Vol.27 No.4

한전 전력연구원에서 개발한 고효율 아민계 습식 $CO_2$ 흡수제(KoSol-5)를 적용하여 0.1 MW급 Test Bed $CO_2$ 포집 성능시험을 수행하였다. 500 MW급 석탄화력발전소에서 발생되는 연소 배가스를 적용하여 하루 2톤의 $CO_2$를 처리할 수 있는 연소 후 $CO_2$ 포집기술의 성능을 확인하였으며 또한 국내에서는 유일하게 재생에너지 소비량을 실험적으로 측정함으로써 KoSol-5 흡수제의 성능에 대한 신뢰성 있는 데이터를 제시하고자 하였다. 그리고 주요 공정변수 운전 및 흡수탑 인터쿨링 효율 향상에 따른 에너지 저감 효과를 테스트하였다. 흡수탑에서의 $CO_2$ 제거율은 국제에너지기구 산하 온실가스 프로그램(IEA-GHG)에서 제시하는 $CO_2$ 포집기술 성능평가 기준치($CO_2$ 제거율: 90%)를 안정적으로 유지하였다. 또한 흡수제(KoSol-5)의 재생을 위한 스팀 사용량(재생에너지)은 $2.95GJ/tonCO_2$가 소비되는 것으로 산출되었는데 이는 기존 상용 흡수제(MEA, Monoethanol amine)의 평균 재생에너지 수준(약 $4.0GJ/tonCO_2$) 대비 약 26% 저감 된 수치이다. 본 연구를 통해 한전 전력연구원에서 개발한 KoSol-5 흡수제 및 $CO_2$ 포집 공정의 우수한 $CO_2$ 포집 성능을 확인할 수 있었고, 향후 본 연구에서 성능이 확인된 고효율 흡수제(KoSol-5)를 실증급 $CO_2$ 포집플랜트에 적용할 경우 $CO_2$ 포집비용을 크게 낮출 수 있을 것으로 기대된다. The absorption efficiency of amine $CO_2$ absorbent (KoSol-5) developed by KEPCO research institute was evaluated using a 0.1 MW test bed. The performance of post-combustion technology to capture two tons of $CO_2$ per day from a slipstream of the flue gas from a 500 MW coal-fired power station was first confirmed in Korea. Also the analysis of the absorbent regeneration energy was conducted to suggest the reliable data for the KoSol-5 absorbent performance. And we tested energy reduction effects by improving the absorption tower inter-cooling system. Overall results showed that the $CO_2$ removal rate met the technical guideline ($CO_2$ removal rate : 90%) suggested by IEA-GHG. Also the regeneration energy of the KoSol-5 showed about $3.05GJ/tonCO_2$ which was about 25% reduction in the regeneration energy compared to that of using the commercial absorbent MEA (Monoethanolamine). Based on current experiments, the KoSol-5 absorbent showed high efficiency for $CO_2$ capture. It is expected that the application of KoSol-5 to commercial scale $CO_2$ capture plants could dramatically reduce $CO_2$ capture costs.

A long-term test of a new CO2 sorbent (KEP-CO2P2) in a 0.5 MWe CO2 capture test bed

김경숙,양석란,Joong Beom Lee,Tae Hyoung Eom,류청걸,이하진,Tae-Sung Bae,이영부,이세진 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.4

The performance of a new dry CO2 sorbent KEP-CO2P2 was tested for an extended period of time of 650hours in a 0.5 MWe CO2 capture test bed at Hadong coal-fired power plant. The mass-produced CO2 dry sorbent,KEP-CO2P2 was tested for CO2 sorption and regeneration capacity. With modification of the process as well as the useof KEP-CO2P2 sorbent in a 0.5 MWe CO2 capture test bed, 85% (81-90%) CO2 removal rate was achieved in continuousoperation of 650 hours. Samples were collected and analyzed using particle size analyzer (PSA), ion chromatograph(IC), inductively coupled plasma (ICP), field emission-scanning electron Microscope (FE-SEM), electron probeX-ray micro-analyzer (EPMA) and X-ray diffractometer (XRD). The analysis showed that KEP-CO2P2 was not affectedby SOx, and there were no side reactions to consume K2CO3. However, the regeneration of the sorbent was not completeto need future investigation.

Applicability of Solvay Process as a CO₂ Capture and Utilization

( Choon-ki Na ),( Jee-june Song ) 한국환경기술학회 2019 한국환경기술학회지 Vol.20 No.5

A novel approach was investigated using chemical reactions based on a Solvay process, where ammoniated sodium-rich solution is reacted with carbon dioxide (CO₂), to capture and convert CO₂ into useful and reusable products. The effects of ammonia (NH₃), sodium (Na) and CO₂ concentrations on the CO₂ capture in the Solvay process were assessed using a bubble column reactor. CO₂ gas was used a mixture of 20-80 vol% CO₂ in pure air. The experimental results indicated that the optimum concentration of NH₃ as catalyst was 3-5 wt% (1.76-2.94 M), the minimum concentration of Na was >26 g/L, and the CO₂ capture increased as increased the Na concentration in the ammoniated absorption solution. The formation of sodium bicarbonate (NaHCO₃) was found to play a key role in capturing CO₂ in the Solvay process. The concentration of CO₂ in feed gas was not significant factor in CO₂ capture using the Solvay process. The results indicated that this approach can be used to capture CO₂ from flue gases or to refine natural and synthetic gases, while at the same time contributing to the utilization of CO₂ as a useful product, such as a sorbent for desulfurization.