Many of the problems associated with process burners are related to the burner tips. In fact, some say there may not be two process heaters in the world that have identical burner designs: While the burner bodies may be the same, the tips are custom designed for the specific application. Each burner normally has multiple fuel tips, and each tip usually has multiple holes (sometimes called ports). The number, size and angle of the holes in each tip are carefully selected to give the desired flame characteristics (flame length, for instance) and burner performance (to minimize NOX emissions, for example). Therefore, tips design, installation and maintenance are critical to ensuring proper burner operation.
One way the burners’ firing rates can be determined is by using individual fuel flowmeters. However, this is usually prohibitively expensive in plants that have many process heaters and where each heater has multiple burners. Instead, the most common method used to determine the firing rate of individual process burners is with fuel capacity curves -- graphs of firing rate vs. fuel pressure.