Further Development of a Suspension Fired Reactor To Assess the Relative Performance and Synergistic Effects during the Combustion of Coal Blends

Abstract

An improved suspension-firing reactor has been constructed and a new experimental procedure developed that is able to assess the relative performances of coals and coal blends. The method measures the total combustion time of the samples by measuring the exit gas analysis from the reactor on a continuous basis. The new equipment and procedure overcome some deficiencies that were identified in an earlier suspension-firing method that was based on the extent of burnout of the sample at the end of an arrested combustion test. The presence of a synergistic effect on blending is indicated by a difference between the actual performance of the blend and that predicted by additivity from the performance of the individual coals and the composition of the blend. Three sets of binary blends and their parent coals, which have also been used in utility pf furnaces, have been tested in the suspension-firing reactor. The results have been compared with the performance at the commercial scale, as indicated by the C content of the electrostatic precipitator fly ashes. In all three cases, the performance as predicted by the suspension-firing reactor was consistent with that observed at the commercial scale. This suggests that this relatively straightforward small scale test may provide a useful route for the assessment of coals prior to purchase and for the optimization of blend performance.

Entrained-Flow Gasification of Oil Sand Coke with Coal: Assessment of Operating Variables and Blending Ratio via Response Surface Methodology

“…4,12 Furthermore, all of the above studies have used a classical "one-factor-at-a-time" methodology to study the effect of operating variables and also the blending ratio. The known shortcomings of this method in identifying the effect of experimental factors and their interactions can be resolved using a statistical design of the experiment based on response surface methodology (RSM).…”

“…Attempts to predict the gasification performance of a blend from the performance of its components has not been successful, especially for those fuels that are markedly different in their properties. , Furthermore, all of the above studies have used a classical “one-factor-at-a-time” methodology to study the effect of operating variables and also the blending ratio. The known shortcomings of this method in identifying the effect of experimental factors and their interactions can be resolved using a statistical design of the experiment based on response surface methodology (RSM). , Having fewer experimental runs, detailed identification of experimental factors and their interactions, and the ability to optimize the desired response variables are the main advantages of RSM.…”

Biomass Suspension Combustion: Effect of Two-Stage Combustion on NOx Emissions in a Laboratory-Scale Swirl Burner

“…Synergistic Effect for NO Reduction of Co-firing. In coal combustion, it has been reported that a synergistic effect on blending is observed, 40 which is indicated by a difference between the actual performance of the blend and that predicted by the addition of the performance of individual fuels and the blend ratio. In Figure 8, a lower level of NO is shown than expected when co-firing wood and straw, when considering the additive property from co-firing wood/gas and straw/gas in Figure 6.…”