Determination of Biomass-Coal Blending Ratio during Indirect Cocombustion by the ¹⁴C-Liquid Scintillation Count Method

Increased utilization of biomass gasification gas-coal cocombustion has created a need for an accurate method to measure biomass-coal blending ratios. The inexpensive and cost-effective C-14-liquid scintillation count (LSC) method has attracted worldwide attention. In this study, the blending ratios (in the range of 1-10%) during biomass gasification gas-coal cocombustion were determined using the C-14-LSC method, and the accuracy and precision were analyzed in detail. Meanwhile, the blending ratio uncertainty caused by inaccuracies in each factor during the calculation process was quantitatively analyzed. The results of the blending ratios showed a perfect linear fit with the actual values. The absolute and relative uncertainties were both less than +/- 0.43% and +/- 9.27%, respectively. Additionally, the relative uncertainties of the majority of the groups were less than +/- 5%. The accuracy of the C-14-LSC method was not affected by the types of fuel or the blending ratios. The absolute deviation was positively related to the blending ratio, while the relative deviation was negatively related to it. Both deviations decreased with increasing C-14 activity of the biomass gas. The primary factors that influenced the uncertainty in the measured blending ratio were the( 14)C activities of the flue gas and the pure biomass. Except for the C-14 activity of biomass, the influence of the other factors on the uncertainty of the measured blending ratio decreased as the blending ratio increased. [GRAPHICS]