multistagged and stagged fuel burner.

A multistaged combustion burner designed for in-furnace NO_x control and high combustion efficiency is being evaluated for high nitrogen content fuel and waste incineration application in a 0.6 MW package boiler simulator. A low NO_x precombustion chamber burner has been reduced in size by approximately a factor of two (from 600 to 250 ms first-stage residence time) and coupled with (1) air staging, resulting in a three-stage configuration, and (2) natural gas fuel staging, yielding up to four stolchlometric zones. Natural gas, doped with ammonia to yield a 5.8 percent fuel nitrogen content, and distillate fuel oil, doped with pyridine to yield a 2 percent fuel nitrogen content, were used to simulate high nitrogen content fuel/waste mixtures. The multistaged burner reduced NO emissions by 85 percent from emission levels from a conventional unstaged burner mounted on a commercial package bollerTA minimum NO emission level of 110 ppm was achieved in the fuel oil tests, from a level of 765 ppm for conventional firing. This is compared with a 160 ppm minimum NO level achieved in gaseous fuel tests, from an uncontrolled level of 1000 ppm. Boiler fuel staging, or reburnlng, appears to be superior to air staging for high combustion efficiency due to its minimal fuel-rich core and second flame front in the boiler.

Burner Design Features:

• Stable flame over a wide range of conditions
• Turndown of 10:1 or greater for most cases
• Compact flame shape
• Reasonable cost and great value
• Combustion air dampers are controlled by gears for precise control
• Bearings are used for the combustion air damper shafts for smooth, precise operation
• Configurations available: plenum mounted or individual wind-box
• One (1) primary gas tip with staged fuel gas port
• 310 Stainless Steel (Type HK) gas tips
• Staged Air annulus around burner tile assembly

Burner Design Information

Burner Model:	GB Staged Air Pseudo Staged Fuel Burner
Fuels:	Gas Only
Description:	Round Flame Pseudo Staged Fuel
NOx Reduction Method:	Staged Fuel
Predicted NOx Emissions Range (Natural Draft):	35 ppmv to 70 ppmv
Predicted NOx Emissions Range (600°F/316°C Air Preheat):	50 ppmv to 90 ppmv
Combustion Air Induction:	Natural, Forced, Induced & Balanced Draft
Mounting Options:	Up-fired and Side-fired
Natural Draft Heat Release Range:	1 MM to 20 MM Btu/hr [0.293 to 5.860 MW]
Forced Draft Heat Release Range:	1 MM to 50 MM Btu/hr [0.293 to 14.650 MW]
Turndown:	10:1
Typical Excess Air Range:	10% to 25%