Hydrate-Based Multistage Biogas Separation Using a Novel Jet Impingement Stream Reactor

摘要

Hydrate-based separation and capture technology, as a green and economical gas separation technology, can be used to purify biogas by removing CO_2 to increase the calorific value and energy density. To achieve pilot-scale biogas separation, a 15 L pilot-scale reactor with novel jet impingement stream was designed for fast and efficient CH_4 recovery and CO_2 capture and pure CH_4 was obtained by multistage separation in this work. Hydrate nucleation and growth were enhanced by jet impingement stream in aqueous solution with 5.0 wt % tetrabutylammonium bromide. The space velocity of the reactor reached a maximum value of S57 h~(-1) the gas uptake reached up to 1.00 mol/L at 4.0 MPa; and the fastest time to reach 80% of the rate of gas uptake was about 2.5 min at 3.0 MPa and 277 K. The effects of the pressure and temperature driving force on the CH_4 concentration in residual gas, CH_4 recovery rate, CO_2 capture ratio, and gas hydration rate were studied. By a four-stage hydrate-based gas separation process, the CH_4 concentration could be increased from 50.0 to about 95.1%. This work provides insights for the industrial application of continuous hydrate-based biogas separation.