Fire All Dual Fuel Burner - 3514

Combustion Performance

Oil: Oil viscosity at the burners must not exceed 70 to 90 seconds redwood. Minimum atomizing air pressure at the burners is 21”wg for light oil, 40”wg for heavy oil.

Gas: Atomizing air (6”wg minimum) should be left on to protect the atomizer. Maximum required natural gas pressure at the burner for stoichiometric ratio is about 25% of the combustion air pressure.

Air/Fuel Ratio: 3514 Dual-Fuel Burners are stable with at least 100% excess air. They also can operate with excess fuel without root formation, but additional air for complete combustion must be available in the furnace near the burner.

Turndown: FireAll Burners can be turned down to atomizing air only (with fuel to match) except when burning residual oils in a cold, tight furnace. For prolonged operation on atomizing air only, specify an alloy burner nose if furnace temperature is above 850°C.

Hot Air: 3514 Burners are designed for use with ambient air. They are suitable for some preheated air applications where the burner can withstand up to 350°C.

Flame Supervision

Flame safeguards are recommended for all installations. An ultraviolet cell will monitor pilot or main flame. Pilots must be interrupted after a preset ignition period (usually 15 seconds) so flame detectors monitor main flame only. Purge UV with cleaning air to keep oil fog off the lens.

Burner Blocks / Installation

Burner blocks are cast refractory rated for 1500°C furnace temperature. They are replaceable in the field, except for the 3514-10A whose mounting must be returned to the factory for burner block replacement (or purchase a spare mounting plate with a burner block cast onto it). Burner blocks should be supported securely in the furnace wall by a layer of castable refractory (not insulation) at least 9" thick all around the burner block, extending back to the furnace shell and securely anchored to it. For furnace walls thicker than the length of the burner block, the tunnel beyond the end of the burner block should be flared 30–45° from the center line, starting at the OD of the burner block.

Jacketed Burner Blocks: 3514 Burners are available with support jackets around the burner block for applications where the burner block is not supported by furnace refractory. Jackets are available in three different metals and have maximum temperature ratings for each. They must be protected with sufficient insulation so as not to exceed rated temperature. Maximum temperature rating for jacket metals depends upon frequency of heat-up/cool-down cycles. As an example, batch annealing furnaces that are heated and cooled every day should use the “intermittent exposure” ratings. Continuous annealing furnaces that remain at the same temperature for months at a time can use the higher “continuous” rating.