Microencapsulation of liquid solvents (MECS) has been proposed as a means of increasing the rate of absorption in gas separation processes. Surface renewal theory was used to rigorously quantify the increase in absorption microencapsulation could provide, compared to traditional packed columns. The results indicate that, for chemical solvents, gas flux will be similar in the two cases, while for physical solvents gas flux into MECS may be larger, owing to the reduction in spatial scales. However, previous publications may have overestimated the increase in surface area that microencapsulation can provide by approximately 3-10 times. Internal fluid flow inside fluidized MECS was also studied, and it was found that gas flux will be similar for stationary and fluidized particles. Overall, microencapsulation can be expected to increase gas absorption rates by approximately an order of magnitude for chemical solvents, and up to 2 orders of magnitude for physical solvents. (C) 2018 American Institute of Chemical Engineers