| Abstract |
In this paper, we will discuss Zeeco's development and application of flameless combustion technology in process heaters over the past approximately 13 years. Flameless combustion is the use of internal flue gas recirculation to change the composition of the fuel gas by entrainment of flue gasses to lower peak flame temperature and reduce thermal NOx. This "conditioning" of the fuel gas causes the fuel gases to combust with a much lower luminosity, creating "flameless" combustion. This "conditioning" of the flue gas creates a host of burner design problems, however. This new fuel gas composition burns at lower temperatures, making it more difficult to stabilize. Several methods of stabilizing this conditioned fuel mixture are discussed, during both normal and abnormal operating conditions. Some methods rely on furnace temperatures sufficient to bring the fuel to auto ignition temperature. These designs often have a "startup" and a "run" mode. Zeeco's GLSF Free-Jet burner utilizes hot refractory ledges to stabilize the flame during all operating conditions, eliminating the need for different operational modes. Other design concerns such as overall cost of ownership, flame dimensions, and burner spacing will also be discussed, as well as how the Zeeco GLSF Free-Jet burner addresses these concerns. |
