| OCR Text |
Show "NOx Reduction by Low Pressure Steam Addition" Adjustments on the air registers were made during Tests 1-3. The range for zero steam addition for Tests 1-3 plus Test 5 was 1.2 to 2.2 % oxygen dry at the arch. The NOx & CO ppmV values corrected to 3% oxygen dry data are plotted on Figure 5 versus arch oxygen concentration. As expected the NOx make increased with increasing oxygen concentration. The CO concentration minimizes at about 1.6 % oxygen dry at the arch. 2. Effect of Steam Due to the substantial difference in the morning tests (1- 3) operating conditions from the afternoon tests (4-10) as indicated by the fuel gas rates in Figure 4, only the latter were used in correlating the results, Figure 6. The coefficients in the 2nd degree polynomial fits are: x = PSIG ppmV = A [X2] +B [X] +C ; R2 NOx, PPM V 0.036608 -3.2851 3 106.42 0.969 CO, PPMV 0.0072914 -0.534498 1 6.61 0.896 02,PPMV 0 -0.0086 2.00 0.252 a. NOx Make Steam addition effectively reduced NOx. The reduction is attributed to probable reduction in local peak flame temperatures and the reduction in oxygen concentrations. The 0.10 Lb NOx / MMBtu HHV EPA limit occurred at about 6 PSIG and the test target value of 0.08 at about 1 3 PSIG. This will permit using 50 PSIG plant steam in the future. Although the trend line indicates a minimum NOx make at 44 PSIG. A straight line sloping downward fit the data closely for the 19, 29 and 49 PSIG values b. CO Make The CO concentration diminished with increasing steam pressure up to about 35 PSIG. Jordan Loftus ScD Page 7 |
