Heat Transfer in a bitumen tanker

I am trying to model a steel tanker filled with molten bitumen. The tanker is insulated and the bitumen is heated by two propane burners ( in form of U) located at the bottom.

For the bitumen I have Non-isothermal Flow-Laminar ,

For the gaseous phase above the bitumen: Non-isothermal Flow-Laminar (not sure).

For the propane: Pipe Flow module (I am not sure if I can use it for a gas)

Also I have Heat transfer in solids for all solid structure with convection to the exterior.

I need to simulate the propane because my goal is to analyze the different configurations of heaters and their impact in the temperature profiles , specifically , the risk of reaching ignition conditions at the interface bitumen/gaseous phase.

Are the modules ok for this simulation ? I always have some kind of error message.

Thanks,