Application of Different Combustion Models for Simulating the Co-combustion of Sludge with Coal in a 100 MW Tangentially Coal-Fired Utility Boiler

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• 作者：Peng Tan ; Lun Ma ; Qingyan Fang ; Cheng Zhang ; Gang Chen
• 刊名：Energy & Fuels
• 出版年：2016
• 出版时间：March 17, 2016
• 年：2016
• 卷：30
• 期：3
• 页码：1685-1692
• 全文大小：547K
• ISSN：1520-5029

文摘

Co-combustion of sludge with coal is a promising sludge disposal approach. In this study, three different combustion models, including different turbulent gas-phase combustion and char surface combustion sub-models, were employed to simulate the combustion and emission characteristics of co-combusting sludge with coal in a 100 MW tangentially coal-fired utility boiler. By comparison of the numerical results from different combustion models to a set of full-scale coal–sludge co-combustion field experiments, a precise and suitable computational fluid dynamic (CFD) model was finally developed. The comparison result demonstrated that the finite-rate/eddy-dissipation model together with the multiple-surface-reaction model, which have carefully considered the effect of high moisture content on the fuel ignition and char combustion processes, were competent in modeling the characteristics of coal–sludge co-combustion. On the basis of the developed numerical model, the ignition, char burnout, and NO_x emission characteristics of co-firing different mass contents of sludge were further investigated. The result demonstrated that co-firing sludge with coal would cause a slight delay on the fuel ignition and a decline on the char burnout. The high moisture and high nitrogen in sludge had a dual promotion effect on NO formation, leading to an increase of NO_x emission after co-firing sludge.