Look at the initial conditions. It’s defined as 100% CO2 for the background IC and 70% CO2 for the bed region. There is no other fluid species defined. If you want the simulation to contain air prior to the injection of CO2, then you need to include it - you can get the data from the (built-in) species database:
Also, the CO2 that’s in your attached case has 0 for the heat of formation - I’m not sure why that is, according to the database the value should be -47328.105 and that’s what you would have gotten if you imported the CO2 data from the species database.