A novel burner arrangement scheme with annularly combined multiple airflows for wall-tangentially fired pulverized coal boiler

摘要

To improve the performance of tangentially-fired pulverized boiler, a new burner arrangement scheme with annularly combined multiple airflows is proposed and its performance is thoroughly investigated with a previously validated 660 MW lignite boiler model. Results show that compared with conventional wall-tangentially fired boiler, the in-furnace aerodynamic field under the proposed burner arrangement scheme is obviously improved, embodying as reduced airflow deflections, increased furnace fullness and alleviated phenomenon of airflow scouring furnace walls. Besides, coal combustion behavior is also improved, resulting in increased combustion temperature and enhanced heat transfer process in the main burners & rsquo; region. Furthermore, the reduced flue gas swirling intensity mitigates the deviations of flue gas velocity and temperature in the upper furnace region, which finally lowers the unevenness of heat absorption on the suspended heating surfaces. With the improvement of the abovementioned aspects, the safety and economy of tangentially-fired boilers can be largely increased. Considering the increasingly enlarged boiler capacity and the widespread use of low-rank coal, the proposed burner arrangement scheme can be of great use in retrofitting the existing boilers and designing new ones.(c) 2021 Elsevier Ltd. All rights reserved.