Types of boiler burners

Turn down ratio indicates the flexibility of burner to cope with different loads without losing efficiency.

TRD = fuel consumption at max load/ fuel consumption at minimum load.

Pressure jet burner TDR 3:1

Rotary cup TDR 15:1

Steam blast TDR 20:1

Ultrasonic  TDR 15:1 

• Simple pressure jet burner

Atomization of fuel is achieve by forcing fuel under pressure through swirler and orifice at end of burner. Pressure energy converted to velocity.

Spinning of oil is given by swirler and by the centrifugal force on the spray causing it to atomize

Advantage

1. simple, cheap, robust
2. no moving parts,
3. easy maintenance
4. no need air or steam

Disadvantage

1. Very low TDR
2. easily block by debris

• Steam blast

Steam and fuel mixed and expanded in the nozzle and creates good atomization

Disadvantage

1. Condensate of steam result in poor performance unstable performance

• Ultrasonic burner 

Resonator tip vibrate at a frequency of 5 MHz to 20 MHz under influence of high speed steam or air.

Very small droplets size produced which allow stable flame

Atomization is achieve by energy of ultrasonic waves imparted on fuel by resonaotor tip

Advantage:

1. 1. Simplified operation
   2. Reduce of acid corrosion problems

Rotary cup burner 

Fuel is supplied into inner surface of highly spinning cup, due to centrifugal force, oil film becomes thinner as cup circumference increase due to conical shape of cup.

Finally fuel is discharge from lip of cup on fine spray, Widely popular due to wider turn down ratio

Advantage:

1. 1. 1. No need steam or air
      2. Low fuel pressure required, robust, suitable on small installation.
      3. Stable flame can be achieve with low fuel flow.

Drawing: Boiler burners