Emission Characteristics of the 0.03 MW Oxy−Fuel Combustor

Abstract

Emission characteristics of the 0.03 MW oxy−fuel combustor have been experimentally investigated under a wide operating range of velocity and quarl angle. To simulate the NO emission characteristics of industrial oxy−fuel furnaces, we mixed 3% nitrogen by supplied oxygen with pure oxygen. When a quarl is not fitted, the flame length decreased with increasing inlet fuel or oxidizer velocity, mainly because of the increase in turbulent intensity. In the case of the high-speed injection of fuel or oxidizer without a quarl, NO emission levels decrease because high-speed injection enhances the entrainment of product gas to the flame zone as well as decreases the overall combustion residence time. When a quarl is fitted, the flame length increases with expanding quarl angle because of the decrease in turbulent intensity. The NO emission level increases with expanding quarl angle because both the entrainment of product gas is prevented and the overall combustion residence time is increased with the installation of a quarl.

Impact of co- and counter-swirl on flow recirculation and liftoff of non-premixed oxy-flames above coaxial injectors

“…Non-premixed flames are often anchored to the fuel nozzle rim z/d 1 = 0, but in many cases they may also stabilize further downstream z/d 1 > 6 [8][9][10]. Turbulent non-premixed methane/air swirling flames are almost never attached to the injector rim at ambient conditions [21], but O 2 -enriched flames exhibit a wider variety of topologies [10]. These two features have motivated this study in which the impact of co-and counter-rotating swirl on the flame and flow patterns is characterized both at the outlet of the injector z/d 1 = 0 and further downstream up to z/d 1 = 15 with the help of optical diagnostics.…”

Scaling relations for the length of coaxial oxy-flames with and without swirl

“…The flame length is defined as the furthest point on the axis with a combustion reaction [12,17] . In many cases, the length of diffusion flames is determined by recording its global emission in the visible band [12,19,20] or the emission of selected intermediate radicals [9,17,18] . In these studies, the flame length is commonly correlated to the stoichiometric mixing length L S .…”

Scheme of O2/CO2 Combustion with Partial CO2 Removal from Recycled Gas. Part 1: Superlow NO Emission

“…For the whole system, the global conversion ratio from fuel N to exhausted NO is defined (11) Using our experimental results (eqs 2 and 3) for the coal described in Table 2 and the theoretical analysis of the system described in this section, our new scheme of combustion can now be evaluated and parameters such as the NO concentration and global conversion ratio of fuel N to NO can be obtained. In this work, the oxygen/fuel stoichiometric ratio = 1.2 was used.…”