Staged combustor, rich-lean

The data acquired in the evaluation of a subscale, rich-lean staged combustor indicated a substantial tolerance for fuel property variations while retaining a low emissions operation characteristic. In particular, it was observed that ... 

H-Coal, and EDS middle distillates, and hydrotreated Paraho shale oil residual were tested in a subscale 5-inch diameter, staged rich-lean combustor at conditions representative of baseload and part power settings of 30-MW utility combustion turbine. A minimum NO emission level corrected to 15% oxygen of approximately 35 ppmv was attained for all the fuels despite fuel bound nitrogen levels of up to 0.8 percent by weight. 

The NO levels obtained from the staged combustion investigation were substanially less than obtained from a lean combustor (Figure 12). At exit temperatures representative of baseload operation, the rich-lean combustor produced N0X levels approximately one-third the levels associated with the lean combustor. Unlike the staged combustor emissions increased with increased fuel-bound nitrogen. 

The staged combustor data have been normalized at a primary equivalence ratio of 1.55 for alltest fuels (Figure 16). The fractional increase in heat flux is generally consistent with the lean combustor temperature parameter data presented by Westinghouse ( 3). As with the correlation of the rich-lean smoke data, the heat flux parameter does not display a unique correlation to fuel hydrogen content. 

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