Co-combustion of solid biomass in pulverized anthracite-coal firing boilers

Introduction. Combustion of solid biomass as a mix with domestic coal in exsisting industrial and utility boilers can not only reduce harmful emissions but also diversifies the generations' fuel base. It also allows effective utilization of solid food processing wastes which otherwise would be dumped and thus cause a strong unfavorable environmental impact. Materials and method. The pulverized pine-sawdust and anthracite co-combustion has been carried out in down fired experimental unit at 30 kg/h fuel rate. The kinetics of the pine sawdust cokes' termal degradation has been studied in fluidized bed unit. The thermal decomposition kinetics of pine wood and straw pellets of wheat, rape, corn and soy were studied by thermogravimetric (TG) method. Result ans discussion. The co-combustion of pulverized domestic anthracite and wood in the unit VGP-100V has proven its technical realizability and a noticeable potential to significantly improve the quality of low-reactive anthracite combustion. As a result the optimum share of solid biomass of approximately 10% has been determined. This share allows the stabilization of flame without natural gas addition along with the highest level of fuel carbon conversion. The internal kinetic mode of pine cokes' samples' combustion was determined for particles size 0,1-1,6 mm in temperatures' range of 390-560 degrees C at the fluidized bed unit RSK-1D. Some stages of organic biomass thermal decomposition (namely demoisturization, devolatilization and coke burn out) and their kinetics have been detected by means of TG methods. Comparison of pine sawdust and wheat straw pellets' devolatilization kinetics with those available in literature sources indicates that the existing minor deviations may be explained by the difference in sample heating rate, size of sample particles, variation in organic and mineral composition of samples, methods of reaction constants calculation and interpretation. At the same time, the kinetic constants of the devolatilization stage for pellets of different crops straw examined in the present work turned out to be close enough. Conclusion. Presented results can be used in calculations of the some stages co-combustion processes which take place in TPP's.