Beginners Guide To Furnaces

What is a fired heater?

• An insulated enclosure that uses the heat created by the combustion of fuels to heat fluids contained inside coils

• A device that introduces fuel and air into a heater at the desired velocities, turbulence, and concentration to establish and maintain proper ignition and combustion

• A small burner that provides ignition energy to light the main burner

• A vertical conduit used to discharge flue gas to the atmosphere

As the hot combustion gases rise, they create a low-pressure area within the venting system, drawing in fresh air from the surrounding environment to replace the rising hot air. This natural draft or airflow helps facilitate the removal of combustion byproducts, such as carbon monoxide, from the furnace to the outside.

• Stack effect

• valve

• pump

• turbine

What is the purpose of refractory in a fired heater?

• To shield the heater casing from excess temperatures

• To transfer heat to the tubes primarily by radiation

• To introduce a variable resistance in order to regulate the flow of flue gas or air

• To provide ignition energy to light the main burner

What is the function of the convection section in a fired heater?

• To transfer heat to the tubes primarily by convection

• To shield the remaining convection-section tubes from direct radiation

• To connect two or more tubes

• To discharge flue gas to the atmosphere

What is the draft in a fired heater?

• Movement (negative pressure, vacuum, or suction) of the flue gas measured at any point in the heater

• Heat lost to the surroundings from the casing of the heater and ducts

• Radiant section excluding the coils and refractory

• Factor used to calculate the overall heat transfer coefficient

What is a natural draft heater?

• A heater in which a stack effect induces the combustion air and removes the flue gases

• A heater that uses a fan to remove flue gases and to maintain negative pressure in the heater to induce combustion air without a forced-draft fan

• A heater for which combustion air is supplied by a fan or other mechanical means

• A heater that uses forced-draft fans to supply combustion air and uses induced draft fans to remove the flue gases

Match the following

• portion of the heater in which the heat

• stack

• device that introduces fuel and air into

• radiant section

• small burner that provides ignition ener

• convection section

• vertical conduit used to discharge flue

• pilot

• portion of the heater in which heat is t

• burner

Label the draft type for each furnace

b

a

c

d

Forced

Balanced

Induced

Natural