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Benedict Prah,윤린(Rin Yun) 대한설비공학회 2017 설비공학 논문집 Vol.29 No.7
Formation and transportation of CO₂-hydrate slurry was conducted by circulating saturated water with CO₂ through a double-tube type heat exchanger which was cooled down by brine. The inner diameter and circulation length of the heat exchanger were 1 inch and 20 m, respectively. Water in tank was supersaturated by injected CO₂ and the operation pressure was maintained at 3,000 to 4,000 kPa with fluid-temperature of less than 9℃. CO₂ hydrate mass fraction was calculated based on density of CO₂-hydrate slurry mixture. Results showed that the CO₂-hydrate slurry could be circulated without blockage for 1 hr. Circulation status of the CO₂-hydrate slurry was also visualized.
Two Phase Simulation of CO₂-hydrate Mixture in Tube
Benedict Prah,Rin Yun(윤린) 대한설비공학회 2015 대한설비공학회 학술발표대회논문집 Vol.2015 No.11
The formation of CO₂ hydrate during CO₂ transportation presents a complex two phase flow (particle-particle interactions) within tube. The scale-up of such flow is very problematic, yet these flow phenomena are not fully understood. A two-dimensional CFD model for CO₂ hydrate mixture flow in tube is derived based on the Eulerian multiphase flow modelling approach in which the two phases consists of CO₂ gas and CO₂ hydrate particles. A coupled Eulerian multiphase and non-isothermal flow model is developed based on COMSOL Multiphysics built-in application modes. The model couples the mass, momentum, and energy equations for the two phases to solve for the temperature and flow characteristics of the CO₂ hydrate mixture flow in tube. The model assumes no phase change for the CO₂ hydrate particles during flow within the tube. CO₂ hydrate particles are found to settle during flow even under high speed operation. The related heat transfer coefficient of the CO₂ hydrate mixture computed from the model was 1058 W/m²K.
CO<sub>2</sub> hydrate slurry transportation in carbon capture and storage
Prah, Benedict,Yun, Rin Elsevier 2018 Applied thermal engineering Vol.128 No.-
<P><B>Abstract</B></P> <P>Based on a proposed hydrate-based gas separation and the utilization of this technology, CO<SUB>2</SUB> hydrate slurry transportation in pipeline from capture plants to storage sites is proposed in this paper. Two different transport processes are considered in the present study. The concept of CO<SUB>2</SUB> hydrate slurry transportation in pipelines has many advantages over the current approaches of CO<SUB>2</SUB> transportation. Transferring CO<SUB>2</SUB> in hydrate slurry status reduces energy input for transportation and eliminates of hydrate blockage in pipelines thus reducing the overall cost of gas transportation. The effect of CO<SUB>2</SUB> hydrate slurry formation in the absence and presence of anti-agglomerants is investigated in an experimental flow loop. The effect of four low dosages of 0.3, 0.5, 0.7 and 1.0wt% of anti-agglomerant; Tween 80 (non-ionic surfactant) on CO<SUB>2</SUB> hydrate is investigated. Discussions on CO<SUB>2</SUB> hydrate formation kinetics, induction time, slurry density and slurry flow within the experimental loop are provided. In the experiment, hydrate mass fraction ranged from 8 to 32%. The result indicates that CO<SUB>2</SUB> hydrate slurry flow and circulation in the flow loop is significantly enhanced with anti-agglomerant.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Hydrate slurry mass fraction generated in the tests ranged from 8 to 32wt%. </LI> <LI> Circulation status for CO<SUB>2</SUB> hydrate slurry in a pipeline is highly enhanced with AA. </LI> <LI> CO<SUB>2</SUB> hydrate slurry was produced and maintained during circulation for an hour. </LI> </UL> </P>
Experimental Study on CO₂ Hydrate Flow Pattern and Pressure Drop in a Flow Loop
Benedict Prah,Rin Yun 대한설비공학회 2018 대한설비공학회 학술발표대회논문집 Vol.2018 No.6
Recently, research focus has shifted from prevention of hydrate formation in oil/gas pipelines to utilization of gas hydrate in various areas of application such as cold storage, district cooling, gas transportation and others. These applications mostly require the development of gas hydrate as a transportable hydrate slurry. Various studies have shown that hydrate formation kinetics, as well as flow properties, are improved in the presence of additives. However, knowledge on the pressure drop characteristics of CO₂ hydrate slurry in the presence and absence of chemical additives is inadequate. This study investivates the pressure drop and flow obseravtions during CO₂ hydrate formation and flow. The influence of anti-agglomerant dosage and slurry flow rate on pressure drop is addressed in this work. The result shows that pressure drop steeply increases during the active formation of hydrate particles, a process accompained by temperature rise in the loop. It was aslo observed that increasing the slurry flow rate increased the pressure drop.
Dynamic Modelling and Simulation of IGCC process with Hydrate-based CO₂ Capture and Transport
Benedict Prah,Rin Yun 대한설비공학회 2018 대한설비공학회 학술발표대회논문집 Vol.2018 No.11
A transient simulation of hydrate-based CO₂ capture process with clathrate slurry transportation from coalfired Integrated Gasification Combined Cycle (IGCC) was performed using TRNSYS simulation software. For the simulation of hydrate formation, an equation based thermodynamic reaction is employed to estimate formation rate of CO₂ hydrate in the reactor. Approximately, 40% of the syngas feed amount is converted to hydrate slurry in the hydrate formation. The maximum corresponding heat amount generated with formation of hydrate slurry quantity is estimated to be about 2.5 ㎿.
Heat Transfer and Pressure Drop Simulation of CO2-Hydrate Mixture in Tube
Benedict Prah,윤린 대한설비공학회 2017 International Journal Of Air-Conditioning and Refr Vol.25 No.1
The formation of CO2 hydrate during CO2 transportation presents a complex two-phase flow within tube. A two-dimensional CFD model for CO2 hydrate mixture flow in tube is derived based on the Eulerian multiphase flow modeling approach in which the two phases consist of CO2 gas and CO2 hydrate particles. A coupled Eulerian multiphase and nonisothermal flow model without phase-change is developed based on COMSOL Multiphysics built-in application modes. The model couples the mass, momentum, and energy equations for the two phases to solve the temperature and flow characteristics of the CO2 hydrate mixture flow in tube. CO2 hydrate particles are found to settle down during flow even under high velocity operation. The pressure drop increased linearly with inlet volume fraction from 1.29 kPa for 0.1–5.2 kPa for 0.5, and the related overall heat transfer coefficients of the CO2 hydrate mixture computed from the model ranged from 980 to 4000W/m2K with variation of CO2 hydrate volume fraction.
Benedict Prah,이원준,윤린 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.1
The issue of CO 2 hydrate has drawn attention in terms of the pipeline transporting and injection process of the captured CO 2 . Designing a pipeline network under onshore or offshore conditions for transporting CO 2 and designing a pipeline for injection to a reservoir requires knowing the exact CO 2 thermodynamic status for safety in the pipeline and for controlling operational facilities, including compressors and gas boosters. In the present study, a model for estimating the in-tube heat-transfer coefficient for a CO 2 -hydrate gas mixture was developed by considering the significant effects of the temperature difference between the CO 2 -hydrate crystallization temperature and the actual operational temperature on the heat transfer coefficient. In addition, a pressure drop model for a CO 2 -hydrate gas mixture was developed by introducing a pressure ratio of P/P crit and the Breault and Mathur model, which was developed for estimating a pressure drop for solid particles and gas flow in a pipeline.