Nitrogen burner

Among the various detectors specific for nitrogen, the NPD (Nitrogen Phosphorus Thermionic Detector) we will consider, is based on the following concept the eluted components enter a conventional FID burner whose air and hydrogen flows are controlled to eliminate the response for hydrocarbons. 

This justifies all the work undertaken to arrive at fuel denitrification which, as is well known, is difficult and costly. Moreover, technological improvements can bring considerable progress to this field. That is the case with low NO burners developed at IFF. These consist of producing separated flame jets that enable lower combustion temperatures, local oxygen concentrations to be less high and a lowered fuel s nitrogen contribution to NOj. formation. In a well defined industrial installation, the burner said to be of the low NO type can attain a level of 350 mg/Nm, instead of the 600 mg/Nm with a conventional burner. 

In a rotary kiln, the burner can produce both thermal and fuel NO, if the fuel contains nitrogen. Many soHd waste streams also contain nitrogen, typically as much as 20 wt %, which contributes to the fuel NO pathway. Key sources of soHd waste fuel nitrogen include plastics, nylons, dyes, and other process wastes. Nylon, for example, is 33 wt % nitrogen. 

Environmental. Stringent environmental laws require that nitrogen oxides (NO ) and sulfur oxides emission from furnaces be drastically reduced. In many parts of the world, regulations require that NO be reduced to 70 vol ppm or lower on a wet basis. Conventional burners usually produce 100 to 120 vol ppm of NO. Many vendors (McGill, John Zink, and North American) are supplying low NO burners. 

Fuel-Staged Burners Use of fuel-staged burners is the preferred combustion approach for NO control because gaseous fuels typically contain little or no fixed nitrogen. Figure 27-36 illustrates a fuel-staged natural draft refineiy process heater burner. The fuel is spht into primaiy (30 to 40 percent) and secondary (60 to 70 percent) streams. Furnace gas may be internally recirciJated by the primaiy... 

Control of oxides of nitrogen can be accomplished by catalysts or ab-sorbants, but most control systems have concentrated on changing the combustion process to reduce the formation of NOj. Improved burners, change in burner location, staged combustion, and low-temperature combustion utilizing fluidized-bed systems are all currently in use. These combustion improvement systems do not generate waste products, so no disposal problems exist. 

New low-NO, burners are effective in reducing emissions from both new power plants and existing plants that are being retrofitted. Low NO, burners limit the formation of nitrogen oxides by controlling the mixing of fuel and air, in effect... 

TTte most cost-effective methods of reducing emissions of NO are the use of low-NO burners and the use of low nitrogen fuels such as natural gas. Natural gas has the added advantage of emitting almost no particulate matter or sulfur dioxide when used as fuel. Other cost-effective approaches to emissions control include combustion modifications. These can reduce NO emissions by up to 50% at reasonable cost. Flue gas treatment systems can achieve greater emissions reductions, but at a much higher cost. 

Reduce nitrogen oxide emissions by use of natural gas as fuel, use low-NO, burners, and use hydrogen peroxide and urea in stainless steel pickling baths. 

The steam flow was (3.55 ton/hr, but the nitrogen flow was only 0.4 ton/hr, the most that could be made available. As the system cooled, air was drawn in. Some liquid hydrocarbon had been left in a blowdown vessel, and the air and hydrocarbon vapor formed a flammable mixture. According to the report, this moved up the stack and was ignited by the pilot burner, which was still lit. It is possible, however, that it was ignited by the maintenance operations. 

SNCR programs typically employing liquid additive formulations based on urea (carbamide, NH2CONH2), together with stabilizers and modifiers, are particularly useful. The additive is sprayed into the combustion area, after the burner. The use of such additives reduces the NOx level by between 50 and 90% by converting NOx into harmless nitrogen and water. 

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