Combustion and Self-Desulfurization Characterization of Blended Low-Rank Coals for Improved Resource Utilization in Fluidized Bed Boilers  

作　　者：SU Lipeng ZHANG Cong ZHANG Yongsheng WANG Tao WANG Jiawei 

机构地区：[1]Key Laboratory of Power Station Energy Transfer Conversion and System,Ministry of Education,North China Electric Power University,Beijing,102206,China

出　　处：《Journal of Thermal Science》2024年第3期1242-1256,共15页热科学学报（英文版）

基　　金：supported by the National Natural Science Foundation of China(52276110)。

摘　　要：The co-combustion of low-rank coals through fluidized bed boiler(CFB)is an effective approach to enhance the level of resource utilization.To date,there has been a lack of investigation concerning the co-combustion kinetics and self-desulfurization characteristics of coal slime,coal gangue,and raw coal.In this study,we adopted multiple model-free and model-fitting methods to comparatively analyze co-combustion kinetics of blended coals on the basis of thermogravimetric data.Then,the sulfur balance and self-desulfurization of blended coals in the co-combustion were intensively investigated using a tube furnace set-up.The results reveal that in the presence of coal gangue in blended coals,the average activation energy(E_(a))falls within the range of 65.7 kJ/mol to 100.4 kJ/mol,as determined by four model-free methods.Conversely,in the absence of coal gangue,only the Flynn-Wall-Ozawa(FWO)and Friedman(FM)methods are deemed appropriate for calculating the average E_(a),yielding a value of 77.3 kJ/mol.The first order reaction model is confirmed to be reliable for analyzing the co-combustion kinetics of low-rank blended coals.Irrespective of the specific composition of the blended coal,a significant linear correlation exists between the Ea and the natural logarithm of the pre-exponential factor(lnA)within an extensive range of parameters.Moreover,the addition of coal gangue to the blended coal substantially enhances the self-desulfurization level,resulting in an increase from 25.7%to60.7%at 1073 K.The self-desulfurization efficiency exhibits a good linear relationship with both the mass ratio of coal gangue to coal slime and the molar ratio of calcium to sulfur.In a practical implementation,the optimal addition ratio of coal gangue is a trade-off between the self-desulfurization efficiency and the ignition capacity.

关 键 词：coal slime coal gangue fluidized bed boilers self-desulfurization resource utilization 

分 类 号：X752[环境科学与工程—环境工程] TK229.66[动力工程及工程热物理—动力机械及工程]