Clathrate Hydrate Framework Construction Enhanced by Waste Bio-Shavings for Efficient Methane Storage
Liang Yang, Jiajie Wang, Ni Liu, Yingming Xie, Guomin Cui, Daoping Liu
Abstract
Improving the hydrate formation rate as well as gas storage capacity is significant for gas hydrate technology applications. Porous woodshavings with different liquid–solid ratios (RL/S) were prepared to capture methane in the form of hydrate. The kinetics of methane hydrate formation in wet shavings were studied using an unstirring reactor at pressures ranging from 5.0 to 8.0 MPa and a temperature of 274.2 K. The results demonstrated that the liquid water spread well on the surface of the shavings and permeated into their interior micropores. Wet multi-stack shaving beds could provide abundant channels for gas diffusing to the film water coated on the surface of the shavings. The rough and irregular wooden surface was capable of contributing a considerable number of nucleation sites for hydrate formation. The skeletons of wet shavings aided in the construction of a three-dimensional hydrate bridge and framework, which accelerated the upward migration of pore water and gravity water to form a hydrate crown. Compared with bulk water, the water dispersed by shavings greatly accelerated hydrate nucleation and growth. The RL/S ceilings of wet samples that allowed for a significant quantity of methane hydrate formation were 11.0 (8.0 MPa), 9.0 (7.0 MPa), 8.0 (6.0 MPa), and 7.0 (5.0 MPa). The wet beds with the RL/S of 8.0 exhibited the best gas storage performance at all pressures except 5.0 MPa. Furthermore, 10 cycles of repeated tests showed that wet shavings could store gas extremely stably, with cyclic peak gas uptakes ranging from 146.0 to 154.1 cm3·cm–3. A hypothesis of “hydrate shell–bridge–framework construction enhanced by bio-shavings” was proposed to illustrate the fast hydrate formation in the porous shavings.