Industrial Application of an Improved Multiple Injection and Multiple Staging Combustion Technology in a 600 MWe Supercritical Down-Fired Boiler

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• 作者：Minhang Song ; Lingyan Zeng ; Zhichao Chen ; Zhengqi Li ; Qunyi Zhu ; Min Kuang
• 刊名：Environmental Science & Technology
• 出版年：2016
• 出版时间：February 2, 2016
• 年：2016
• 卷：50
• 期：3
• 页码：1604-1610
• 全文大小：397K
• ISSN：1520-5851

文摘

To solve the water wall overheating in lower furnace, and further reduce NO_x emissions and carbon in fly ash, continuous improvement of the previously proposed multiple injection and multiple staging combustion (MIMSC) technology lies on three aspects: (1) along the furnace arch breadth, changing the previously centralized 12 burner groups into a more uniform pattern with 24 burners; (2) increasing the mass ratio of pulverized coal in fuel-rich flow to that in fuel-lean flow from 6:4 to 9:1; (3) reducing the arch-air momentum by 23% and increasing the tertiary-air momentum by 24%. Industrial-size measurements (i.e., adjusting overfire air (OFA) damper opening of 20–70%) uncovered that, compared with the prior MIMSC technology, the ignition distance of fuel-rich coal/air flow shortened by around 1 m. The gas temperature in the lower furnace was symmetric and higher, the flame kernel moved upward and therefore made the temperature in near-wall region of furnace hopper decrease by about 400 °C, the water wall overheating disappeared completely. Under the optimal OFA damper opening (i.e, 55%), NO_x emissions and carbon in fly ash attained levels of 589 mg/m³ at 6% O₂ and 6.18%, respectively, achieving NO_x and carbon in fly ash significant reduction by 33% and 37%, respectively.