Convective heat transfer and pressure drop of CO2 hydrate mixture in buried pipelines.

Transportation of captured CO2 plays a vital role in the carbon capture and storage process. In this work, the influence of different soil temperature conditions on hydrate formation and dissociation is examined in buried pipelines transporting CO2 gas. Hydrate formation pressures between 0.28 MPa to 0.32 MPa and soil temperatures of 0, 3, 6 and 9 °C were considered. Heat transfer coefficient for heat transfer from the surrounding soil to the hydrate mixture and pressure drop in a pipeline was measured in a 4 m long test facility. Flow visualization were made to observe hydrate flow behaviour. Low heat transfer coefficient was recorded for high temperature difference between soil and hydrate mixture. Heat transfer coefficient and pressure drop under the experimental conditions ranged from 38 to 1215 W/m2K and 0.05 MPa to 0.5 MPa respectively.

捕获的二氧化碳（CO₂）的输送环节，在碳捕获与封存（Carbon Capture and Storage, CCS）全流程中发挥着至关重要的作用。本研究针对输送CO₂气体的埋地管道，探究了不同土壤温度条件对水合物（Hydrate）生成与分解过程的影响。实验设定的水合物生成压力区间为0.28 MPa至0.32 MPa，土壤温度分别取0、3、6和9 ℃。通过总长4米的试验装置，本研究测量了周围土壤向水合物混合物传热的传热系数（Heat Transfer Coefficient）以及管道内的压力降（Pressure Drop）。开展了流动可视化（Flow Visualization）实验，以观测水合物的流动行为特征。实验结果表明，当土壤与水合物混合物间的温差较大时，测得的传热系数偏低。本实验条件下，传热系数与压力降的取值范围分别为38 W/m²K至1215 W/m²K，以及0.05 MPa至0.5 MPa。