煤粉工业锅炉炉膛结焦的影响因素及改进对策

The influencing factors and improvement strategies of coking in the furnaceof coal powder industrial boilers

炉膛结焦严重威胁燃煤锅炉运行的的安全稳定运行,某供热热水锅炉燃烧器周围及同水平面后墙侧墙位置结焦现象严重影响锅炉的长期运行并增加安全隐患。通过对结焦情况长期观察,基于煤灰的化学成分对结焦影响的分析,结合燃煤锅炉燃烧结焦的机理,采取优化锅炉运行氧含量、增大内二次风占比、减小煤粉颗粒粒径、优化煤种等措施对不同条件下的结焦现象进行对比分析,以探讨减缓炉膛结焦进程的改进对策。研究发现煤种是影响煤粉工业锅炉燃烧结焦的最主要因素,优化煤粉粒径及配风也有一定影响;通过现场取样对锅炉现用煤粉进行煤质及灰成分对比分析,并根据灰成分进行结渣性判别指标计算,结果表明锅炉燃烧现用煤种的灰熔融性温度较低,煤灰软化温度为1170℃,属于典型的易结焦煤种,结渣性严重。综合分析认为:锅炉燃烧煤种发生改变,煤的灰熔融温度较低是影响煤粉工业锅炉燃烧结焦的最本质因素。为进一步解决现场实际问题,采取破坏煤灰中酸碱比提高硅比,提升煤的灰熔融温度,配合调节煤粉粒径等措施。经调整后的锅炉连续运行时长明显延长,结焦状况得以改善,说明燃烧调整改进对策取得良好的效果。

Coking in the furnace seriously threatens the safe and stable operation of coal-fired boilers.The phenomenon of coking around the burner of a heating and hot water boiler and on the side walls of the back wall at the same level seriously affects the long-term operation of the boiler and increases safety hazards.By observing the coking situation for a long time and analyzing the impact of the chemical composition of coal ash on coking,combined with the mechanism of coking in coal-fired boiler combustion,measures such as optimizing the oxygen content of boiler operation,increasing the proportion of internal secondary air,reducing the particle size of coal powder,and optimizing coal types are taken to compare and analyze the coking phenomenon under different conditions,in order to explore improvement strategies to slow down the coking process in the furnace.Research has found that coal type is the most important factor affecting coking during combustion in coal powder industrial boilers,and optimizing coal powder particle size and air distribution also has a certain impact;through on-site sampling,the coal quality and ash composition of the coal powder used in the boiler were compared and analyzed,and the slagging discrimination index was calculated based on the ash composition.The results showed that the ash melting temperature of the coal used in the boiler combustion was relatively low,and the ash softening temperature was 1170℃,which belongs to the typical coal type that is prone to coking and has serious slagging.Based on comprehensive analysis,it is believed that the change in coal type during boiler combustion and the lower ash melting temperature of coal are the most essential factors affecting coking during coal powder industrial boiler combustion.To further solve practical problems on site,measures such as breaking the acid-base ratio in coal ash and increasing the silicon ratio,increasing the ash melting temperature of coal,and adjusting the particle size of coal powder are taken.The continuous operation time of the adjusted boiler has been significantly extended,and the coking condition has been improved,indicating that the combustion adjustment improvement measures have achieved good results.