임계점 부근의 이산화탄소-메탄 혼합물의 관내 응축 열전달 특성 연구

Abstract

The condensation heat transfer coefficient and pressure drop for pure CO₂ and CO₂+CH₄ mixture were investigated under the near-critical condition, which simulates the CO₂ transporting conditions under Carbon Capture and Storage (CCS) process. The experimental facility consisted of a test section, heat exchangers, mass flow meters, temperature sensors, a magnetic gear pump, and a differential pressure transducer. The test section made with a copper tube was assembled with Polyvinyl Chloride (PVC) pipe to form a double tube. The condensation temperature and mole fraction of CH₄ in the CO₂ mixture ranged from 20℃ to 30℃, and 1% to 5%, respectively. The mass flux was changed from 500, 600, and 700 kgm-2s-1. The two-phase flow pattern under the set conditions was estimated to be the annular flow. When the mole fraction of methane in the mixture increased from 1% to 5% at 20℃ of condensation temperature, the average condensation heat transfer coefficients and the pressure drop for CO₂+CH₄ decreased from 4.97% to 19.9%, and 30.0% to 54.5%, respectively, compared to those for pure CO₂