TY  - EJOU
AU  - Li, Chenhong 
AU  - Han, Guojin 
AU  - Zhong, Hua 
AU  - Zhang, Chao 
AU  - Zhang, Rui 
AU  - Choe, Jonggeun 
AU  - Xing, Chen 
AU  - Cao, Xuewen 
AU  - Bian, Jiang 

TI  - Flow and Heat Transfer Characteristics of Natural Gas Hydrate Riser Transportation
T2  - Energy Engineering

PY  - 2025
VL  - 122
IS  - 4
SN  - 1546-0118

AB  - Extracted natural gas hydrate is a multi-phase and multi-component mixture, and its complex composition poses significant challenges for transmission and transportation, including phase changes following extraction and sediment deposition within the pipeline. This study examines the flow and heat transfer characteristics of hydrates in a riser, focusing on the multi-phase flow behavior of natural gas hydrate in the development riser. Additionally, the effects of hydrate flow and seawater temperature on heat exchange are analyzed by simulating the ambient temperature conditions of the South China Sea. The findings reveal that the increase in unit pressure drop is primarily attributed to higher flow velocities, which result in increased friction of the hydrate flow within the development riser. For example, at a hydrate volume fraction of 10%, the unit pressure drop rises by 166.65% and 270.81% when the average inlet velocity is increased from 1.0 to 3.0 m/s (a two-fold increase) and 5.0 m/s (a four-fold increase), respectively. Furthermore, the riser outlet temperature rises with increasing hydrate flow rates. Under specific heat loss conditions, the flow rate must exceed a minimum threshold to ensure safe transportation. The study also indicates that the riser outlet temperature increases with higher seawater temperatures. Within the seawater temperature range of 5°C to 15°C, the heat transfer efficiency is reduced compared to the range of 15°C to 20°C. This discrepancy is due to the fact that as the seawater temperature rises, the convective heat transfer coefficient between the hydrate and the inner wall of the riser also increases, leading to improved overall heat transfer between the hydrate and the pipeline.
KW  - Natural gas hydrate; multi-phase flow; heat transfer; numerical simulation

DO  - 10.32604/ee.2025.060970