Effect of Blending Straw Powder Into Coal Gangue on Loading-Up Characteristics of the Circulating Fluidized Bed Generator Unit

Abstract To increase the contribution to the regional environment, the feasibility of blending agricultural residues was explored by a circulating fluidized bed (CFB) generator unit using coal gangue as the single fuel. In this study, straw powder was chosen to blend into the coal gangue, and the whole thermal system was built as a dynamic model based on self-programming and GSE software. Blending affects the load-increasing process from 75 % to 100 % rated power (Pe) with a load variation rate of 1 % Pe/min. With the blended fuel, the deviation of the output power was almost unchanged, and the maximum deviation of the live steam pressure was reduced by 0.04 MPa. With the blending ratios of 10 % and 20 %, the energy efficiencies of the whole unit were improved by 0.48% and 0.81%, respectively, the accumulative deviations of live steam temperature were reduced by 10.4% and 16.5%, respectively, the accumulative deviations of reheat steam temperature were reduced by 13.3% and 18.2% respectively, and the maximum deviations of bed temperature were increased to 8.9 °C and 9.5 °C respectively. The increased fluctuations in bed temperature are still far from the safe boundary, so the CFB generator unit can safely load up with the blending ratios of 10 % and 20 %.