掺烧石油焦锅炉降低飞灰含碳量研究
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摘要
某炼化企业自备电站410t/h掺烧石油焦循环流化床锅炉(简称CFB锅炉)飞灰含碳量高达15%以上,导致锅炉效率下降。通过对锅炉床层温度、一次及二次风量、过剩含氧量、床层压差、石灰石添加量等因素进行优化调整:当床温度为880～920℃之间时,飞灰含碳量降低效果较好,锅炉热效率提高;适当减小一次流化风量,增加二次风量在100～110t/h之间,有助于燃煤的充分燃烧,飞灰含碳量也相应降低;控制烟气含氧量在4.5%～5.5%范围内,床层压差在4.5～5.0kPa之间,对降低飞灰含碳量有明显作用;在保证脱硫效果的情况下适当减小炉内石灰石脱硫剂的使用量,也可降低飞灰含碳量。在运行中可根据飞灰含碳量的变化调整燃烧工况,维持床层温度、一二次风量、过剩含氧量、床层压差和石灰石添加量在合理范围内,以优化密相区和稀相区的燃烧份额,降低机械不完全燃烧热损失,有效降低锅炉飞灰可燃物至8%以下,可提高锅炉热效率0.5%。
The carbon content of fly ash of the 410 t/h petroleum coke-fired circulating fluidized bed boiler(CFB boiler) in the self-provided power plant of a refinery was higher than 15%,leading to a decrease in the boiler efficiency.The boiler bed temperature,primary and secondary air volume,excess oxygen volume,bed pressure difference and limestone addition were optimized and adjusted.The results showed that when the bed temperature is between 880℃ and 920℃,the carbon content of fly ash can be reduced effectively and the thermal efficiency of the boiler can be improved.Appropriately reducing the primary fluidized air volume and increasing the secondary air volume to between 100 t/h and 110 t/h are helpful to the full combustion of coal,and the carbon content of fly ash decreases correspondingly.Controlling the oxygen content of flue gas within the range of 4.5%-5.5% and the bed pressure difference between 4.5-5.0 kPa can remarkably reduce the carbon content of fly ash.Appropriately reducing the use of limestone desulfurizer in furnace under the condition of guaranteeing the desulfurization effect can also reduce the carbon content of fly ash.During operation,the combustion conditions can be adjusted according to the change in the carbon content of fly ash,and the bed temperature,primary and secondary air volume,excess oxygen content,bed pressure difference and limestone addition are maintained within a reasonable range to optimize the combustion fraction for dense phase and dilute phase,reduce the heat loss due to combustibles in refuse,effectively reduce the combustible content of fly ash of boiler to below 8%,and improve the thermal efficiency of boiler by 0.5%.
The carbon content of fly ash of the 410 t/h petroleum coke-fired circulating fluidized bed boiler(CFB boiler) in the self-provided power plant of a refinery was higher than 15%,leading to a decrease in the boiler efficiency.The boiler bed temperature,primary and secondary air volume,excess oxygen volume,bed pressure difference and limestone addition were optimized and adjusted.The results showed that when the bed temperature is between 880℃ and 920℃,the carbon content of fly ash can be reduced effectively and the thermal efficiency of the boiler can be improved.Appropriately reducing the primary fluidized air volume and increasing the secondary air volume to between 100 t/h and 110 t/h are helpful to the full combustion of coal,and the carbon content of fly ash decreases correspondingly.Controlling the oxygen content of flue gas within the range of 4.5%-5.5% and the bed pressure difference between 4.5-5.0 kPa can remarkably reduce the carbon content of fly ash.Appropriately reducing the use of limestone desulfurizer in furnace under the condition of guaranteeing the desulfurization effect can also reduce the carbon content of fly ash.During operation,the combustion conditions can be adjusted according to the change in the carbon content of fly ash,and the bed temperature,primary and secondary air volume,excess oxygen content,bed pressure difference and limestone addition are maintained within a reasonable range to optimize the combustion fraction for dense phase and dilute phase,reduce the heat loss due to combustibles in refuse,effectively reduce the combustible content of fly ash of boiler to below 8%,and improve the thermal efficiency of boiler by 0.5%.
引文
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[2]王春波,侯伟军,陈传敏,等.富氧燃烧循环流化床锅炉炉内传热特性[J].中国电机工程学报,2011,31(20).
[3]霍肇明.循环流化床YG-75/3.82-M燃烧控制与调整[J].中国科技博览,2011(10):21-21.
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