OCR Text |
Show furnace draft, furnace chamber temperature, furnace exit gas temperature, stack gas temperature and stack gas analysis. The FMR burner was upfired from the floor of a tall vertical furnace with a square cross section. This furnace is lined with refractory fiber and surrounded by a water cooling jacket. The amount of cooling surface covered by refractory lining and the thickness of the refractory are adjusted to achieve the desired furnace temperature. This burner was tested at a nominal rate of 15 million Btu/hr. Fuel, air and data measurement equipment and the type of data collected for this test were similar to those discussed for the AM R test. Combustion Test Results In each case the burners were tested under conditions simulating an industrial process heater. A wide variety of fuel mixtures, including blends of natural gas, hydrogen, propane and butane, were tested. Some of the most interesting results are included here. AMR Test Results Figure 3 shows the variation of NOx with excess oxygen when firing natural gas on the AMR radiant wall burner. The air preheat was 350 OF for this test. The NOx levels increase as the excess oxygen concentration ' increases. However, even up to the maximum level tested (4.9 % excess oxygen), the NOx level is still well below 40 PPM. The emissions are below 30 PPM over the range of excess oxygen that is typical for this type of furnace. While low, the emissions are seen to increase by a factor of about 35% over the range from 2% to 30/0 excess oxygen. The variation in NOx emissions with excess oxygen when firing 100 mole percent hydrogen fuel gas is shown in Figure 4. The air preheat was also about 350 OF for this test. Somewhat surprisingly, the NOx emissions for natural gas and 100% hydrogen are similar in magnitude. When firing hydrogen, the rate of increase of NOx with increasing excess oxygen is not as great as seen with natural gas. Over the range from 2% to 3% 5 |