A cold flow model was built and operated in order to study the fluid dynamics of a 120-kW chemical looping pilot rig for gaseous fuels. The system consists of two interconnected circulating fluidized bed reactors with globally circulating bed material (dual circulating fluidized bed - DUB). Gas mixing between the two reactors is prevented by moderately fluidized loop seals. In the cold model, both reactors are fluidized with air at two stages to control the solids circulation. The data presented focus on the solids circulation rates and on pressure profiles of both reactors, depending on selected operating parameters like fluidization gas flow rate, level of gas introduction, loop seal fluidization, and solids inventory. The results show high solids circulations in the global loop between the two reactors for the scaled base case operation conditions already at low bed inventories.