煤种掺烧对燃煤机组脱硫系统运行经济性分析

Economical analysis of desulfurization system operation of coal-fired units with mixed-coal combustion

为满足烟气超低排放改造要求,对660 MW燃煤机组脱硫系统进行增容提效改造。在经济煤种掺烧条件下,通过改变负荷、入炉煤硫分的脱硫耦合试验分析了机组脱硫系统运行的经济性,建立了基于脱硫绩效、脱硫费率、时均脱硫费用的计算模型,分析了脱硫系统运行费用和潜能。结果表明:在机组100%负荷运行并满足超低排放要求的条件下,脱硫系统所能承受的最大原烟气SO_(2)含量为2320 mg/Nm^(3),折算入炉煤含硫量为1.1%;当入炉煤硫分大于0.85%后,时均运行费率急剧增大;当入炉煤硫分增大到1.1%以上时,系统各设备全出力运行,缺少冗余,可靠性变差;当入炉煤硫分为0.66%~0.85%时,脱硫系统具有较好的经济性和可靠性。

In order to meet the requirements of ultra-low flue gas emission,the desulfurization system of 660 MW coal-fired unit was upgraded to increase its capacity and efficiency.Applying mixed combustion of economical coals,the economic efficiency of the desulfurization system was analyzed by changing the load and sulfur content of coal.The calculation models were established based on desulfurization performance,desulfurization cost per unit power supply,and hourly average operation cost.The operation cost and potential of the desulfurization system were analyzed.The results showed that,when the unit operated at 100% load and met the ultra-low emission requirements,the maximum SO_(2) content of raw flue gas that the desulfurization system could withstand was 2 320 mg/Nm^(3),which equaled to a coal sulfur content of 1.1%.When the sulfur content of coal in furnace was greater than 0.85%,the hourly average desulfurization cost increased rapidly.When the sulfur content of coal in furnace increased to more than 1.1%,all equipments of the system operated at full capacity,with lack of redundancy and poor reliability.The desulfurization system had a good performance in economy and reliability when the the sulfur content of coal in furnace was 0.66% ~0.85%.