CO₂ reduction-conversion to precipitates and morphological control through the application of the mineral carbonation mechanism

Elsevier 2018 ENERGY Vol.153 No.-

<P><B>Abstract</B></P> <P>This study aimed to verify CO<SUB>2</SUB> reduction and morphological control of its precipitates by applying the CO<SUB>2</SUB> mineralization mechanism under ambient conditions. In the first stage, CO<SUB>2</SUB> absorption-conversion experiments were performed using three types of amines (mono-ethanolamine, MEA; di-ethanolamine, DEA; and methyl-di-ethanolamine, MDEA) to improve the rate and efficiency of CO<SUB>2</SUB> conversion into metal carbonates. In the second stage, CO<SUB>2</SUB> was re-absorbed and supplied as aqueous CO<SUB>2</SUB>, forming MgCO<SUB>3</SUB> and MgCO<SUB>3</SUB>(H<SUB>2</SUB>O)<SUB>3</SUB> precipitates. The formed MgCO<SUB>3</SUB> was analyzed by X-ray diffraction (XRD) and field emission scanning electron microscope (FE-SEM). In particular, MgCO<SUB>3</SUB> was formed only in the MEA solution although other amines were exposed to the same experimental conditions. Therefore, the results showed that the CO<SUB>2</SUB> precipitate morphology could be controlled by the type of the conversion solution used. This study has significance regarding CO<SUB>2</SUB> reduction and utilization because the emitted CO<SUB>2</SUB> could be stored semi-permanently. Furthermore, the formed MgCO<SUB>3</SUB> could be re-used in various industries through morphology control. Therefore, this study verified the potential of the CO<SUB>2</SUB> mineralization mechanism for CO<SUB>2</SUB> reduction and morphology control.</P> <P><B>Highlights</B></P> <P> <UL> <LI> This study investigates the possibility of CO<SUB>2</SUB> precipitates morphology control. </LI> <LI> A CO<SUB>2</SUB> mineralization mechanism with the amine solution was verified. </LI> <LI> MgCl<SUB>2</SUB> and aqueous CO<SUB>2</SUB> formed MgCO<SUB>3</SUB> and MgCO<SUB>3</SUB>(H<SUB>2</SUB>O)<SUB>3</SUB> and its morphology was changed. </LI> <LI> These findings are significant for CO<SUB>2</SUB> reduction and utilization. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Schematic of the purpose of this study and the underlying assumptions.</P> <P>[DISPLAY OMISSION]</P>

Co-occurrence patterns of Korean and Japanese adverbs expressing speculation

Jang Kun Soo 한국일본학회 2018 日本學報 Vol.0 No.115

이 연구에서는 추측을 나타내는 한국어와 일본어 부사를 대상으로 문말의 어떠한 표현과 공기관계를 맺고 있으며, 그 차이점은 무엇인가에 대해 분석하였다. 분석의 대상으로 한 부사는 일본어의 ‘たぶん’, ‘どうやら’, ‘もしかすると’와 이에 대응하는 한국어의 ‘아마(도)’, ‘아무래도’, ‘어쩌면’이다. 분석을 통해 도출한 한일 부사어의 차이점은 다음과 같다. 먼저, 일본어의 부사는 ‘ダロウ’가 나타내는 ‘추량’, ‘ヨウダ/ラシイ/シソウダ’가 나타내는 ‘증거성’, ‘カモシレナイ’가 나타내는 ‘가능성’이라는 문말형식의 의미범주에 따른 공기 양상이 두드러진다는 특징이 있다. 특정 형식과의 공기가 강하고 타 형식과의 공기는 어울리지 않는다는 점에서 부사에 따른 공기 양상이 ‘상보적’인 관계에 있다고 할 수 있다. 다음으로, 한국어의 부사도 특정 형식과의 공기관계가 현저하게 나타나지만, 일본어의 부사에 비해 그 정도가 낮고, 우언적 표현과 공기하는 비율이 높다. 일본어 부사에 비해 ‘추량’, ‘증거성’, ‘가능성’이라는 의미범주와의 공기 양상이 두드러지지 않고 서로 ‘연속적’인 관계에 있다고 할 수 있다. 즉 넓은 의미의 ‘추측’이라는 점에서 사태가 실현되는 개연성의 차이를 나타낸다고 할 수 있다. This study analyzed which expression of a sentence-end Korean and Japanese adverbs for expressing speculation have a co-occurrence relationship and what the difference is. The objects of analysis are Japanese adverbs ‘tabun’, ‘douyara, and ‘moshikasuruto’, and the corresponding Korean adverbs ‘ama(do) (probably)’, ‘amuraedo(seems like・anyway)’, and ‘eojjeomyeon(maybe)’ respectively. The differences between Korean and Japanese adverbs derived from the analysis are as follows: Japanese adverbs are characterized by a remarkable co-occurrence with the semantic categories of sentence-end forms such as ‘conjecture’ indicated by ‘darou’, ‘evidentiality’ indicated by ‘youda/rashii/-shisouda’, and ‘possibility’ indicated by ‘kamoshirenai’. They have a strong co-occurrence with a particular form while having an inconsistent relationship with other forms. In that sense, it can be said that co-occurrences according to adverbs have ‘complementary’ relationships. Korean adverbs also have a strong co-occurrence with a particular form. However, they have a relatively low co-occurrence compared to Japanese adverbs, and instead have a strong co-occurrence with allegorical expression. Moreover, they don’t have as much remarkable co-occurrence with semantic categories such as ‘surmise’, ‘evidentiality’ and ‘possibility’ as Japanese adverbs, but they have a ‘continuous’ relationship to each other. This means that they represent the difference in probability that the situation is realized in the broad sense of ‘speculation’.

다중관형 CO₂ 급탕열교환기의 열적성능에 대한 해석연구

장근선(Keun Sun Chang),최연성(Youn Sung Choi),김영재(Young-Jae Kim) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.8

본 연구에서는길이 4.5 m와 7.5 m의 다중관 CO₂ 급탕 열교환기의 열전달및 압력강하 특성을 ε-NTU 방법을사용하 여 해석하고 결과를 기존의 실험 데이터와 비교하였다. 급탕 열교환기는 쉘측에 물이 흐르고 8개로 구성된 내부 튜브에 CO₂ 를 흐르게 하였으며 열전달 효율을 최대화하기 위하여 대향류로 설계하였다. 각 노드에 대한 물과 CO₂ 냉매의 유동에 대한 에너지 평형 방정식은 단면분할법을 이용하여 해석하였다. 열전달율 계산값은 실험값과 ±5 % 범위 내에서 잘 일치하였다. 반면에 물의 출구온도는 물 유량이 증가함에 따라 거의 선형적으로 감소하며 계산값과 실험값은 ±3 % 내에서 일치하였다. 결과에서 열전달율은 4.5 m와 7.5 m 급탕 열교환기 모두 물 유량 또는 CO₂ 입구온도가 증가함에 따라 거의 선형적으로 증가 하였으며, 반면에 물 유량이 증가함에 따라 물의 출구온도는 선형적으로 감소하였다. CO₂ 압력강하 계산값과 실험값은 CO₂ 가 고유량일 때 5 % 내에서 잘 일치한 반면에 CO₂가 저유량일 때 실험값이 약 20 % 높게 나타났다. In this study, the heat transfer and pressure drop characteristics were evaluated for multi-tube CO₂ water heaters with lengths of 4.5 m and 7.5 m. The evaluation was done using the -NTU method, and the results were compared with experimental data. Water flows through the shell side of the water heater, while CO₂ flows through 8 inner tubes. The heater uses a counter-current design to maximize the heat transfer efficiency. The energy balance equation describing the flows of CO₂ and water for each node is set up using the section-by-section method. The calculated heat transfer rates agree well with the experimental data within ±5 % error. The outlet water temperature decreased linearly with the increase of the water flow rate. The calculated heat transfer rates agreed well with the experimental data within ±3 % error. The results show that the heat transfer rate increases almost linearly with the increase of water flow rate or CO₂ inlet temperature in both the 4.5-m and 7.5-m water heaters, whereas the water outlet temperature linearly decreases with the increase of the water flow rate. The comparison of the CO₂ pressure drop between the calculation and experiment results shows good agreement at the high CO₂ flow rate within 5 % error, but the value is about 20 % higher in the experimental pressure drop at the low CO₂ flow rate.

Flow and Heat Transfer Characteristics of CO₂/Oil Mixtures in a Circular Tube

Byung Ha Kang,Dong Seop Lim 대한설비공학회 2008 International Journal Of Air-Conditioning and Refr Vol.16 No.4

The present study is directed at flow and heat transfer of CO₂ and oil mixtures in a circular tube. PAG and POE oils are considered in this study. Flow characteristics of CO₂ and oil mixtures have been investigated by flow visualization. Pressure drop has been measured in the range of operating mass flow rate from 0.1 to 0.4 ㎏/min in a circular tube. Heat transfer characteristics of CO₂/oil mixtures have been investigated using a counterflow heat exchanger. In case of pure liquid CO₂ as well as CO₂ and POE mixtures, flow are seen to be uniform so that CO₂ and POE oil are still miscible even at flowing state. However, it is found that CO₂ and PAG are not miscible. Pressure drop of CO₂/PAG mixtures are much higher than that of CO₂/POE mixtures as well as pure CO₂ at a fixed mass flow rate. As the concentration of POE oil is increased from 0 to 5 wt%, pressure drop is increased. However, heat transfer rate and heat transfer coefficient of CO₂/POE mixtures are much higher than that of CO₂/PAG mixtures. The f-factor correlation and Nusselt number correlation for CO₂/POE oil mixtures are suggested in this paper.

석탄을 사용한 CO가스 제조를 위한 CO2 전환기술

이호용,박지용,이종대 한국응용과학기술학회 2015 한국응용과학기술학회지 Vol.32 No.4

In this study, the experiment of CO production was performed using carbon dioxide and coal. The synthesis characteristics of CO gas was investigated using the chemical activation method of KOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to coal ratio, the flow rate of gas and reaction temperature during CO2 conversion reaction. Without the catalyst of KOH, the 66.7% of CO2 conversion was obtained at the conditions of T=950℃ and CO2 flow rate of 300 cc/min. On the other hand, the 98.1% of CO2 conversion was obtained using catalyst of KOH at same conditions. It was found that the feed ratio(Coal : KOH = 4 : 1) had better CO2 conversion and CO selectivity than other feed ratios. 본 연구에서는 이산화탄소와 석탄을 사용하여 합성가스 CO를 생산하는 실험을 수행하였다. CO 합성특성은 KOH 촉매를 사용한 화학적 활성화 방법에 의해 조사되었으며, 제조공정은 CO2 전환반응에서 석탄과 활성화 촉매 비율, 가스 유량과 반응온도 등과 같은 실험변수들을 분석함으로서 최적화되었다. KOH 촉매를 사용하지 않은 경우, 반응온도 950℃와 CO2 유량 300 cc/min에서 65% CO2 전환율을 얻었으며, 반면에 촉매를 사용한 경우 같은 반응조건에서 98.1%의 전환율을 얻었다. 석탄의 활성화촉매 반응물의 비(석탄 : KOH = 4 : 1)가 다른 반응물 비에 대해 더 좋은 CO2 전환율과 CO 선택도 보여줌을 알 수 있었다.

석탄을 사용한 CO가스 제조를 위한 CO₂ 전환기술

이호용,박지용,이종대,Lee, Ho-Yong,Park, Ji-Yong,Lee, Jong-Dae 한국응용과학기술학회 2015 한국응용과학기술학회지 Vol.32 No.4

본 연구에서는 이산화탄소와 석탄을 사용하여 합성가스 CO를 생산하는 실험을 수행하였다. CO 합성특성은 KOH 촉매를 사용한 화학적 활성화 방법에 의해 조사되었으며, 제조공정은 $CO_2$ 전환반응에서 석탄과 활성화 촉매 비율, 가스 유량과 반응온도 등과 같은 실험변수들을 분석함으로서 최적화되었다. KOH 촉매를 사용하지 않은 경우, 반응온도 $950^{\circ}C$와 $CO_2$ 유량 300 cc/min에서 65% $CO_2$ 전환율을 얻었으며, 반면에 촉매를 사용한 경우 같은 반응조건에서 98.1%의 전환율을 얻었다. 석탄의 활성화촉매 반응물의 비(석탄 : KOH = 4 : 1)가 다른 반응물 비에 대해 더 좋은 $CO_2$ 전환율과 CO 선택도 보여줌을 알 수 있었다. In this study, the experiment of CO production was performed using carbon dioxide and coal. The synthesis characteristics of CO gas was investigated using the chemical activation method of KOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to coal ratio, the flow rate of gas and reaction temperature during $CO_2$ conversion reaction. Without the catalyst of KOH, the 66.7% of $CO_2$ conversion was obtained at the conditions of $T=950^{\circ}C$ and $CO_2$ flow rate of 300 cc/min. On the other hand, the 98.1% of $CO_2$ conversion was obtained using catalyst of KOH at same conditions. It was found that the feed ratio(Coal : KOH = 4 : 1) had better $CO_2$ conversion and CO selectivity than other feed ratios.

Characteristics of CO₂ hydrate formation/dissociation in H₂O + THF aqueous solution and estimation of CO₂ emission reduction by district cooling application

Kim, Shol,Lee, Seong Hyuk,Kang, Yong Tae Elsevier 2017 ENERGY Vol.120 No.-

<P><B>Abstract</B></P> <P>CO<SUB>2</SUB> conversion by gas hydrate is considered one of most practical technologies in the fields of Carbon Capture, Utilization and Storage (CCUS). In this study, the effects of hydrate formation pressure and concentration of tetrahydrofuran (THF) on the CO<SUB>2</SUB> + THF hydrate formation and dissociation performance are investigated, and the reduction of CO<SUB>2</SUB> emission by applying the CO<SUB>2</SUB> + THF hydrate for district cooling system is also evaluated. The CO<SUB>2</SUB> capture ratio tends to increase with increasing the hydrate formation pressure and THF concentration. It is found that the CO<SUB>2</SUB> regeneration rate increases with decreasing the formation pressure and the increasing rate decreases with time. It is concluded that the optimum conditions for the CO<SUB>2</SUB> + THF hydrate formation and dissociation are 1.5 MPa, THF 1.5 mol% to use hydrate slurry as the working fluid for district cooling application. Also, the dissociation enthalpy of CO<SUB>2</SUB> + THF hydrate was measured by using the high pressure micro-differential scanning calorimeter. The cycle simulation of hydrate cooling system is conducted, and the COP is estimated as 11.55. Finally, it is estimated that 20,684 tons of CO<SUB>2</SUB> emission could be reduced per year if the CO<SUB>2</SUB> + THF hydrate technology is applied to the district cooling system of 51,600 RT.</P> <P><B>Highlights</B></P> <P> <UL> <LI> CO<SUB>2</SUB> hydrate formation and dissociation are experimentally studied. </LI> <LI> CO<SUB>2</SUB> emission reduction by district cooling application is estimated. </LI> <LI> The optimum conditions are 1.5 Mpa andTHF 1.5 mol% for district cooling application. </LI> <LI> The COP of CO<SUB>2</SUB> + THF hydrate cooling system is estimated as 11.55. </LI> </UL> </P>

석탄을 사용한 CO가스 제조를 위한 CO2 전환기술

이호용,박지용,이종대 한국유화학회 2015 한국응용과학기술학회지 Vol.32 No.4

본 연구에서는 이산화탄소와 석탄을 사용하여 합성가스 CO를 생산하는 실험을 수행하였다. CO 합성특성은 KOH 촉매를 사용한 화학적 활성화 방법에 의해 조사되었으며, 제조공정은 CO2 전환 반응에서 석탄과 활성화 촉매 비율, 가스 유량과 반응온도 등과 같은 실험변수들을 분석함으로서 최적화 되었다. KOH 촉매를 사용하지 않은 경우, 반응온도 950℃와 CO2 유량 300 cc/min에서 65% CO2 전 환율을 얻었으며, 반면에 촉매를 사용한 경우 같은 반응조건에서 98.1%의 전환율을 얻었다. 석탄의 활 성화촉매 반응물의 비(석탄 : KOH = 4 : 1)가 다른 반응물 비에 대해 더 좋은 CO2 전환율과 CO 선 택도 보여줌을 알 수 있었다. In this study, the experiment of CO production was performed using carbon dioxide and coal. The synthesis characteristics of CO gas was investigated using the chemical activation method of KOH. The preparation process has been optimized through the analysis of experimental variables such as activating chemical agents to coal ratio, the flow rate of gas and reaction temperature during CO2 conversion reaction. Without the catalyst of KOH, the 66.7% of CO2 conversion was obtained at the conditions of T=950℃ and CO2 flow rate of 300 cc/min. On the other hand, the 98.1% of CO2 conversion was obtained using catalyst of KOH at same conditions. It was found that the feed ratio(Coal : KOH = 4 : 1) had better CO2 conversion and CO selectivity than other feed ratios.

전자빔 기술을 이용한 CO₂ 개질반응 기초연구

이기완 ( Lee Ki-wan ),김조천 ( Kim Jo-chun ),염승열 ( Yum Seung-ryol ),문정식 ( Moon Jeong-sik ) 한국환경기술학회 2000 한국환경기술학회지 Vol.1 No.3

본 연구는 고에너지 전자빔을 이용한 CO₂ 개질 및 자원화 공정의 기초연구로서, 1.5 MeV, 40mA의 선형전자빔가속기를 이용한 PVF재질의 반응기 내에서의 전자빔 CO₂ 개질반응을 실험하였다. 5~10%의 CO₂ 가 함유된 모사가스에 대하여 얻은 실험결과, 전자빔 흡수선량이 클수록 반응율이 높게 나타났고 NH₃양론비는 CO₂ 개질공정의 주요 영향인자이며, 에어로졸형태의 수분첨가는 10~16%의 반응율을 향상시키는 인자로 작용하고 ammonium hydrogen carbonate ammonium carbamate 의 반응 부산물이 얻어짐을 확인할 수 있었다. This is a fundamental study related with CO₂ reforming and recycling of byproducts Using high-energy electron beam. The linear electron beam acclerarator with maximum Energy 1.5 MeV, beam current 40 mA was used for CO₂ reforming of simulated gas in PVF reactor, and simulated gas mixture used in this work are composed 5 to 10% of CO₂ From the experimental results, CO₂ conversion depends on the absorption dose of electron beam, NH₃ stoichiometry is a main factor of CO₂ reforming. Addition of water aerosole in CO₂ reforming elevated the conversion efficience by 10 to 16%. Main components of byproduct from CO₂ reforming are ammonium hydrogen carbonate and ammonim carbamate.

The characteristics of CO2 front dynamic migration in low permeability sandstone oil reservoirs under different miscibility degrees

Jin Yong,Wang Zhilin,Zhang Zhenxin,Lin Bo,Ge Zhengjun,You Qidong,Chen Hao,Liu Xiliang,Xu Chenghao,Gao Shuaiqiang,Wu Yi,Abro Zafar 한국자원공학회 2023 Geosystem engineering Vol.26 No.4

CO2 flooding is a significant technology for oil recovery, to reveal the microcosmic mechanism of CO2 flooding, CO2 slim tube experiments, long core CO2 flooding experiments, gas chromatography analysis experiments, and numerical simulations were carried out. The results show that the miscibility increase can improve the effect of dissolution and diffusion in the CO2-crude oil system, easing the CO2 finger entry phenomena, and delaying gas breakthrough time. Besides, the CO2 -crude oil interaction is enhanced by increasing the pressure difference between the injection well and the production well, which improves the oil recovery of CO2 flooding. Besides, CO2 carries the light and medium components (C4 ~ 25) forward to cross the first miscible zone, which makes the CO2-crude oil system form double miscible zones. This study reveals the rule of CO2 front and light components front under different miscibility degrees of CO2 flooding from the microscopic perspective and deepens the theory of CO2 flooding in low-permeability sandstone reservoirs.