An exemplary adiabatic calcium looping system includes a first fixed-bed reactor having a fixed sorbent bed holding a calcium-based sorbent, and a second fixed-bed reactor having a fixed sorbent bed holding a calcium-based sorbent. The exemplary system includes valve mechanisms for alternately configuring each of the first and second reactors in a carbonator configuration and a calciner configuration. The first reactor is configured in the carbonator configuration when the second reactor is configured in the calciner configuration, and the first reactor is configured in the calciner configuration when the second reactor is configured in the carbonator configuration.