地质科技通报 (Sep 2024)
Kinetic characteristics of methane hydrate in functionalized multi-walled carbon nanotubes and L-leucine compounding system
Abstract
Objective Accelerated the generation of natural gas hydrate is crucial for advancing hydrate-based technologies such as gas storage, gas separation, and CO2 capture. Methods The kinetic characteristics of methane hydrate generated with the wB=0.05% functionalized (hydroxylated, carboxylated, and aminated) multi-walled carbon nanotubes(MWCNT) system, and in combination with the wB=1.0% L-leucine were investigated through constant temperature and constant volume methods. Results The combination of multiwalled carbon nanotubes and carboxylated and hydroxylated multiwalled carbon nanotubes with L-leucine, significantly reduced the induction time for natural gas hydrate nucleation to approximately 25, 22, and 13 minutes, respectively. This promotion effect is comparable to that of the typical promoter sodium dodecyl sulfate, and the promotion effect is better than that of a single additive system. The methane storage density of the compounded system reached 136-142 mg/g. Analysis of both the average and instantaneous methane uptake rates indicated that multiwalled carbon nanotubes had minimal impact on the growth kinetics of methane hydrate during the growth phase. The growth of methane hydrate in both the compounded and L-leucine systems were similar, characterized by a rapid increase in uptake rate to a peak value, followed by a rapid decrease and eventual completion of the growth phase. Conclusion A comprehensive analysis suggests that the combination of MWCNTs and L-leucine synergistically enhances the nucleation rate of methane hydrate, whereas the process and rate of the growth phase are predominantly influenced by L-leucine. This study presents a new idea for exploring the differentiation mechanism of different types of additives in enhancing the kinetics of methane hydrate generation.
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