School of Energy and Power Engineering, University of Shanghai for Science and Technology
Shanghai Power Equipment Research Institute Co., Ltd.
Department of Thermal Engineering, Tsinghua University

2021年国内大部分煤价暴涨，影响到部分地区的电力供应，而新疆准东煤价格稳定且处于低水平，因此安全、稳定地大比例燃烧准东煤的研究非常重要。但是，燃烧准东煤的锅炉会由于准东煤煤质特性及烟气温度过高而产生受热面沾污的现象。以某燃用95%准东煤的660 MW容量四角切圆锅炉为研究对象，研究掌握一次风速、运行氧量、空气分级策略以及煤粉细度对锅炉燃烧温度和NOx排放的影响与控制规律，并在静态和动态工况下实施了针对受热面沾污的控制函数改进。最后，利用受热面沾污监测方法证明了改进对受热面沾污的影响。结果表明，660 MW工况下运行氧量对烟气温度影响最明显，运行氧量由2.0%提升至3.5%时，烟气温度下降99 ℃；运行氧量及主燃区局部平均化学当量比降低可导致NOx明显降低，煤粉细度的变化对NOx的影响不明显；投入改进后的控制函数后，升负荷过程中烟气温升速率从6.18 ℃/min下降至4.26 ℃/min，660 MW工况下最高烟气温度从1 104 ℃下降至1 023 ℃，屏式过热器、低温过热器和低温再热器吸热比例分别上升了0.6%、1.6%和0.9%，表明沾污情况得到了明显改善。330 MW负荷工况下，提高最上层磨煤机的煤粉细度R90至4.9%左右，可有效降低高温再热器底部附近烟气温度，减少可燃物及飞灰沉积，抑制沾污的形成。

In 2021, the price of most of the domestic coal skyrocketed, affecting the stable supply of electric power supply in some regions, while the price of Xinjiang Zhundong coal remains stable at a low level. Thus, the study of safe and stable large-scale combustion of Zhundong coal in boilers is more and more important for the energy supplyHowever, fouling and slagging often occur on the heating surfaces of the boiler due to the characteristics of Zhundong coal and the high temperature of the flue gas. The effects of the operating parameters, including the primary air velocity, operating oxygen content, air staging and coal fineness on the combustion temperature and NOx emission were investigated on a four-corner tangentially fired boiler of 660 MW capacity, which burned 95% Zhundong coal to get the relevant control criterion. Based on the research, the improvement of control function for contamination of heating surfaces was implemented under steady and dynamic working conditions. Finally, the influence of the improvement on the contamination of the heating surfaces was proved by the method of the contamination monitoring of heated surfaces. The results show that, at 660 MW load condition, the operating oxygen content had the most obvious influence on the flue gas temperature at the outlet of the furnace. The flue gas temperature decreased 99 °C when it increased from 2.0% to 3.5%. The reduction of the operating oxygen content and the local mean stoichiometric ratio of the main combustion zone could lead to a significant reduction of NOx emission and the change of the coal fineness had no obvious effect on NOx emission. After the improved control function was implemented, the rate of flue gas temperature decreased from 6.18 to 4.26 °C min−1 during the load increase process, the maximum temperature decreased from 1104 to 1023 °C under 660 MW. The heat absorption ratio of the platen superheater, low-temperature superheater and low-temperature reheater increased by 0.6%, 1.6% and 0.9%, respectively, indicating that the fouling and slagging was significantly reduced. At 330 MW load condition, increasing the coal fineness R90 to around 4.9% of the uppermost mill could effectively reduce the flue gas temperature near the bottom of the high-temperature reheater, reduce the deposition of combustible matter and fly ash, and inhibit the formation of fouling and slagging.

国家自然科学基金重点国际(地区)合作研究资助项目(51761125011)

马达夫，张守玉，何　翔，等. 改善准东煤锅炉受热面沾污的燃烧优化试验研究[J]. 煤炭科学技术，2023，51（8）：304−312

MA Dafu，ZHANG Shouyu，HE Xiang，et al. Experimental study on combustion optimization to alleviate fouling on heating surface of a Zhundong coal Boiler[J]. Coal Science and Technology，2023，51（8）：304−312