OCR Text |
Show Figure 3: (tbs/MMBtu) (PPM) 3 .50 r--------------------, 14,000 3 .00 12,000 2.50 10,000 2.00 8,000 1.50 6,000 1.00 4,000 0 .50 2,000 Westbrook (1986) O .OOL---L--L---L--~-~--~--J--~ 20 30 40 50 60 70 80 90 02 IN OXIDIZER (%) Adiabatic equilibrium NO given in PPM and lbs/MMBtu (gross firing rate) versus percent oxygen in the oxidizer for a methane flame. distinction between the units. NOx concentration is typically measured on a volume basis using a chemiluminescent detector. The important quantity is the weight of NOx formed, which depends on the total flue gas flow rate. This flow rate is greatly reduced when using 02 instead of air so, although the NOx volume concentration increases in the intermediate oxygen levels, the mass concentration decreases. A better unit to use for quantifying NOx is weight of NOx per unit weight of material processed. For example, in the glass industry the NOx regulations are written in lbs NO/ton of glass. Production is directly related to the net energy into the material which is proportional to the available heat. Figure 2 shows Figure 4: (tbs/MMBtu) 3 .50r---------------------. 3.00 2.50 2.00 1.50 1.00 Energy Into Product 0 .50 0 .00 L-_ __L_ _~ _ _...L_ __ L__ _. L.....__ __L_ _~ _.....:::..:s 0 20 30 40 50 60 70 80 90 100 02 IN OXIDIZER (%) Adiabati c equilibrium NO (given in Ibs/MMBtu) versus percer oxygen in the oxidizer for a methane flame based gross energy input (overall firing rate) and net e 5Y into the product. 1990 AFRC Symposium -4- October 1990 |