| OCR Text |
Show by the conventional system, so it is expected that a higher initial cost would be justified for the ARCS based on anticipated fuel savings and reduced maintenance costs that would accrue over the life of the plant. NOx emissions from the ARCS were compared to an equivalently sized reformer with conventional "low-NOx" burners as part of the reformer design study. Although NOx emissions vary significantly as a function of fuel content and combustion air preheat, standard industrial burners used in reformers have NOx emissions in the range of 80 to 100 ppm (corrected to 3 percent O2 in dry flue gas), and conventionallow-NOx reformer burners have emissions of 40 to 50 ppm when burning natural gas at 400°F to 500°F combustion air preheat. The ARCS NOx target is 25 ppm, and the burner firing rates determined in the design study (112 MBtu/hr-ft2 peak, 94 MBtu/hr-ft2 average) are consistent with this target based on radiant burner modeling and experimental results. The dollar value of NOx reduction is dependent on facility location. In the Los Angeles Basin, the South Coast Air Quality Management District (SCAQMD) value for NOx reduction is $24,500 per ton of NOx removed. The difference in NOx emissions between the ARCS reformer and a conventionallow-NOx reformer would be over 4 tons per year based on a fired duty of 35.2 MMBtu/hr (LHV). RADIANT BURNER PERFORMANCE TESTS One of the goals of the ARCS program is to increase the temperature capability of porous surface radiant burners to allow broader use of this technology in industrial applications. Current generation porous surface burners are used in applications requiring process temperatures up to 1000°F, resulting in a typical burner surface temperature of 1800°F to 2000°F. The goal of the ARCS development program is to increase the use temperature of porous surface burners to allow a 2 to 3 year life at burner surface temperatures up to 2300°F. This increased temperature capability will allow the porous surface burner to be used in energy intensive applications in the petrochemical and metals processing industries. During Phase I of the ARCS project, a series of short duration tests were performed at simulated reformer conditions to demonstrate concept feasibility. These tests were followed by the Phase II burner development work currently in progress. A description of the Phase I burner test facility is presented below, followed by a summary of test results. The Alzeta Prototype Process Heater (PPH) test facility was modified to allow testing at the high sink temperatures typical of a reformer heater. Goals of the Phase I tests were as follows: • Demonstrate short term combustion stability of the radiant burner within the required operating envelope. • Determine the effect of high sink temperatures on NOx emissions. 12 |
