Furnace construction and operating conditions

•   Different types of furnace and their functions.
•   Operating conditions. Distribution of heat, influence of operating conditions.
•   Efficiency of energy recovery. Estimation rule, parameters governing furnace efficiency, scope and limitations for improving furnace efficiency.
•   Construction of heat exchange areas and refractory materials: tube bundle arrangement, insulation, type of materials used and operating limits.

Combustion - Burners

•   Combustion conditions: stoichiometric air/fuel ratio, heating value, liquid and gas fuel characteristics, liquid spray.
•   Burners: fuel and air supply and mixture, burner operation, low NOx burner characteristics.
•   Combustion quality: analysis of the oxygen and the unburned material in the flue gases, control of the combustion air flow rate, air/fuel ratio control.
•   Combustion safety: flame detection, control and safety devices on the fuel circuits.
•   Air and flue gas circulation: natural draft, forced draft, pressure differential control, automatic safety devices. Damper or forced draft fan role. Impact of furnace positive pressure.
•   Application:
•   Natural and forced draft pressure profile drawing.
•   Review of draft constraints.
•   Presentation of different types of burners and spraying systems.

Heat transfer and tube coil

•   Heat transfer to the tube bundle: heat flux, conduction, convection and radiation, parameters governing heat transfer, tube skin temperature, type of fuel burned, tube temperatures, fouling effects.
•   Division of the heated fluid into several passes: control of partition, low flowrate safety systems.
•   Heating control: process fluid outlet temperature, fuel flowrate control.
•   Most important furnace temperature and constraints: skin temperature, bridgewall temperature, limits and risk of overcoming
•   Application: furnace temperature profile and heat recovery distribution as a function of fuel burned and combustion air excess.

Furnace operation

•   On-stream furnace operations: monitoring of combustion and heating. Modifying operating conditions. Analysis of disturbances. Key points for safe operation, operating conditions control and follow-up.
•   Start-up and shutdown: preparation, safe ignition procedures, ignition after a short shutdown, normal shutdown, emergency shutdown.
•   Incidents: explosive atmosphere in the radiation zone, tube rupture, unbalancing of the heat, etc.
•   Diagnostic facilities; troubleshooting.
•   Application:
•   Case study of furnaces incidents.
•   Start-up procedure study.