CO₂ 하이드레이트 혼합물의 관내측 열전달 특성

In-tube convective heat transfer coefficient and pressure drop of the CO₂-hydrate and gas/water mixture was investigated in this study. The CO₂-hydrate was formed by injecting water to high pressure gas-state CO₂, and the CO₂-hydrate and water mixture went through double-tube type test section. The test tube was made of stainless steel, and length of test section and diameter of inner tube was 4.0 m, 9.52 mm, respectively. The inlet pressure of CO₂ before mixing part was maintained around 2.0 MPa, and mole fraction of CO₂-hydrate in the mixture was controlled by amount of water injection. The CO₂-hydate mole fraction at test section inlet ranged from 0.4 to 0.65. The formation of CO₂-hydrate was verified by rising temperature of the mixture after mixing under adiabatic condition. Phase equilibrium of CO₂-hydrate was checked by inlet pressure and temperature of the mixture too. The in-tube heat transfer coefficient of the mixture ranged from 2400 to 3000 W/m2K, and the pressure drop was from 30 to 50 kPa.