Circulating fluidized beds (CFBs) are implemented in many different industries ranging from oil and power generation to pharmaceutics. Recently, CFBs are used in carbon capture and sequestration with dry regenerable sorbent. This system is composed of gas-solid multiphase flow, thus the poor gas-solid contact results in the low efficiency of carbon capture. The effect of vertical and radial injecting gas nozzles on the gas-solid mixing is investigated for the better design of the CFB reactor for carbon capture. The Eulerian-Eulerian model in Ansys Fluent 14.0 was used to predict the gas-solid flow in CFB reactor. Three simulation cases are conducted: vertical injection, radial injection, and mixed radial/vertical injection of gas. Radial gas injection improved the uniformity of radial solid distribution compared to vertical injection nozzle since gas from radial injection nozzles greatly affected the solid in the wall region.