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

Hydrate-based separation and capture technology, as agreen andeconomical gas separation technology, can be used to purify biogasby removing CO2 to increase the calorific value and energydensity. To achieve pilot-scale biogas separation, a 15 L pilot-scalereactor with novel jet impingement stream was designed for fast andefficient CH4 recovery and CO2 capture and pureCH(4) was obtained by multistage separation in this work.Hydrate nucleation and growth were enhanced by jet impingement streamin aqueous solution with 5.0 wt % tetrabutylammonium bromide. Thespace velocity of the reactor reached a maximum value of 557 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 about2.5 min at 3.0 MPa and 277 K. The effects of the pressure and temperaturedriving force on the CH4 concentration in residual gas,CH4 recovery rate, CO2 capture ratio, and gashydration rate were studied. By a four-stage hydrate-based gas separationprocess, the CH4 concentration could be increased from50.0 to about 95.1%. This work provides insights for the industrialapplication of continuous hydrate-based biogas separation.

Automated summary

In this study, a 15 L pilot-scale reactor was designed to achieve pilot-scale biogas separation using a novel jet impingement stream. By multistage separation, methane recovery and carbon dioxide capture were achieved, obtaining pure methane. The results showed that the methane concentration could be increased from 50.0% to about 95.1% through a four-stage hydrate-based gas separation process. This work provides insights for the industrial application of continuous hydrate-based biogas separation.