Gas Hydrate Growth Estimation Based on Heat Transfer

Abstract

Gas hydrate growth kinetics is largely ascribed to three main controlling mechanisms: intrinsic kinetics, mass transfer, and heat transfer. In this work, gas hydrate growth has been analyzed on the basis of heat transfer during stirred laboratory cell experiments at a constant pressure using pure methane as the hydrate former (structure I). For this, a heat balance model has been developed. The hydrate growth rate was related to measured gas inflow to maintain pressure in the cell constant. Produced heat from hydrate formation is estimated using the heat balance model, and then the amount of hydrate formed is estimated through the enthalpy of methane hydrate formation. The simulated results from the model give a fair representation of the main growth parameters, gas flow/hydrate growth rate, and cumulative growth/gas consumption. Heat transfer through the hydrate slurry changes with increasing the hydrate content. The analysis suggests inclusion of the transient nature of the heattransfer coefficient for accurate prediction of hydrate growth when modeling based on heat transfer. Taking the transient effect into consideration, good correlation between estimates and measurements were obtained.

Gas Hydrate Growth Kinetics: A Parametric Study

“…However, findings from an earlier work show that the heat transfer coefficient decreases during the hydrate formation process but remains roughly constant at each growth stage, i.e., there is an equilibration in the heat transfer out of the cell during growth stage II [92]. Other related works have indicated an increase in hydrate formation rate with an increase in stirring rate [40,47,48], and in general stirring has been shown to promote mass transfer [60,64,100,101].…”

“…The mass flow meter gives gas consumption as NmL/min (normal mL/min, T ref = 0 • C, P ref = 1 bar) and is independent of temperature and pressure elsewhere in the system (e.g., in the gas container or cell). Based on material balance, we assume that the gas inflow to the cell equals the gas used up for hydrate formation, given a constant pressure in the cell during hydrate growth [92].…”

Monitoring gas hydrate formation with magnetic resonance imaging in a metallic core holder

“…Hydrate formation releases heat, increasing the temperature, while the sample vessel wall is in contact with the confining fluid at 4°C. Hydrate formation may be more favorable near the wall due to heat transfer effects [18]. It has also been reported [19] that adding surfactant to the water phase can create a surface growth pattern during hydrate formation in polymeric vessels.…”

A review of natural gas hydrates and its pipeline transportation technologies in deep water

“…Kashchiev和Firoozabadi的研究成果阐明了单组 分系统中水合物生长驱动力的含义 [30] [32] 将反应状态和平衡状态下的温度差作 为驱动力, 建立了一个联合水合物生长传热和本征 动力学的模型. 类似的, Meindinyo等人 [33] [37] 首先完成了甲烷 和丙烷水合物的热分解实验, 认为水合物分解是一 个受水膜界面传热控制的过程. 随后, Slim和Sloan [1] 研究了甲烷水合物的热分解规律, 认为水合物的分 解是一个移动界面消融过程, 提出描述水合物分解 传热规律的数学模型.…”