秸秆替代煤高炉喷吹的能源消耗及环境影响比较

以秸秆替代部分煤进行高炉喷吹,对收集、运输、破碎和喷吹等过程进行了能源消耗和环境影响的差异性比较。考虑到碱负、荷对高炉顺行的影响,秸秆在煤中的混入比最大应在10%左右。秸秆喷吹的能耗较高,与煤相比,原煤消耗量增加了1倍以上,原油消耗量增加了4倍左右。从秸秆的收集到破碎,污染物排放量都比煤高,尤其在破碎过程,各种污染物的排放量是煤的7倍左右。在高炉喷吹利用过程中,秸秆与煤的CO_2、CO和高炉渣的排放量相差不大。由于秸秆生物质的碳循环特点,冶炼1 t铁水可减少CO_2排放量23kg。根据我国排污费标准和国际CO_2排放指标交易市场价,用秸秆替代煤喷吹,生产1t铁水可降低环境成本2.23元。对于一座2 500 m³高炉,每年可减排CO_2 5.63万t,总环境成本可以降低550万元。

Comparison of Energy Consumption and Environmental Impact of Replacement of Coal with Straw Injection into Blast Furnace

Comparison of energy consumption and environmental impact was made when coal was substituted partially by straw injecting into blast furnace.Considering the effect of basicity load on normal blast furnace operation,the maximum proportion of straw in mixture was about 10%.Energy consumption of straw injection was higher,and coal consumption had doubled or more,and oil consumption increased almost 4 times.In comparison with coal,discharge amount of pollutants was larger,and it was about 7times especially in the process of grinding straw.The discharge amount of pollutants including CO_2, CO and blast furnace slag was about the same in the process of injection.CO_2 emission would reduce 23 kg producing a ton of hot metal because biomass straw is carbon-neutral.Based on pollution discharge fee and market price of international CO_2 emission indicator,environmental cost was reduced by 2.23 yuan producing a ton of hot met al.For a blast furnace of 2 500 m~3 inner volume,the amount of CO_2 emission could reduce 56 300 tons,and total environmental cost reduced by 5.5 million yuan per year.