Influence of the Secondary Air-Box Damper Opening on Airflow and Combustion Characteristics of a Down-Fired 300-MWe Utility Boiler

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• 作者：Feng Ren ; Zhengqi Li ; Yubin Zhang ; Shaozeng Sun ; Xiaohui Zhang ; Zhichao Chen
• 刊名：Energy & Fuels
• 出版年：2007
• 出版时间：March 2007
• 年：2007
• 卷：21
• 期：2
• 页码：668 - 676
• 全文大小：268K
• 年卷期：v.21,no.2(March 2007)
• ISSN：1520-5029

文摘

Experiments with a small-scale furnace for a down-fired pulverized-coal 300-MW_e utility boiler were carriedout on a single-phase test facility to investigate the influence of different secondary air distributions on theaerodynamic field in the furnace. When the secondary air flux of tier E increased within a suitable range, itdid not reverse the fuel-rich flow or shorten the residence time of coal particles in the furnace. Industrialexperiments were also performed on a full-scale boiler. The gas temperature distribution along the primary airand coal mixture flow and in the furnace, and gas components such as O₂, CO, CO₂, and NO_x in the near-wallregion, were measured with damper openings of the E-tier secondary air box at 0% and 30%. At 0%, ignitionof the primary air and pulverized coal mixture was delayed and the gas temperature peak was above theburner arch, with high NO_x emission. Increasing the damper opening to 30% provided the oxygen necessaryfor the initial combustion. This was advantageous for stable combustion and also lowered NO_x emissions andcarbon content in the fly ash.