Recyclable and efficient hydrate-based CH4 storage strengthened by fabrics

Abstract

Due to the high storage capacity and low cost, gas hydrates have great potential in CH4 storage. In this work, four different common fabric materials were used as the CH4 hydrate carriers to enhance the gas–liquid interface and the mass transfer during hydrate growth at 278.2 K and an initial pressure of 6.7 MPa. The strengthen mechanism was further analyzed using a kinetic model and SEM images. Results showed that the water conversions ratios in different fabric materials were 76–92 % which corresponded to the storage capacities ranged from 60 to 65 v/v and the decay in storage capacity was less than 6.3 % within 6 cycles of hydrate formation. The beach pants fabric was found to be the most active in the promotion of CH4 dissolution and hydrate growth where the water conversion ratios were over 90 % and the time required for 63 % water conversion is only about 0.6 h. Kinetic analysis showed that the CH4 diffusion resistance through the hydrate layer was the rate-limiting step although some fabric materials performed well in hydrate growth. SEM images revealed that beach pants induced the hydrate formation with foamy surface which facilitated the gas transportation through the hydrate layer. Based on the multiscale analysis, an ideal fabric material for hydrate formation should be thin, light and knitted where the fibers can induce particle like or foamy hydrates instead of dense and continuous hydrate layer.