基于实测数据的高炉煤气单位热值含碳量推荐值的修正方法

Correction method of the recommended value of carbon content per unit calorific value of blast furnace gas based on measured data

钢铁工业碳排放核算方法依据GB/T 32151.5-2015《温室气体排放核算与报告要求第5部分:钢铁生产企业》所提供的排放因子法,单位热值含碳量(C_(C))作为表征可燃物质在单位热值下碳元素含量的指标,是排放因子法计算碳排放量的重要影响因子。前人对于钢铁工业碳排放研究主要侧重于各种核算方法之间的差异性,而对于单位热值含碳量推荐值准确性鲜有研究。为研究可燃物质单位热值含碳量对于碳排放计算的影响,选择钢铁工业炼铁工序副产气体高炉煤气作为研究对象,基于某钢厂高炉煤气各项指标实测数据,计算得出不同组分(CO和CO_(2))含量下高炉煤气C_(C)实测值,分析不同组分含量高炉煤气低位发热量实测值、全碳组分C_(C)实测值、燃烧过程C_(C)实测值等实测参数变化。结合排放因子法广泛应用的现状,基于C_(C)实测值波动情况,提出3种将C_(C)推荐值修正为燃烧过程C_(C)的方法,在各自适用条件修正值与实测值的偏差均小于5%;最后,用该钢厂高炉炼铁工序2021年有关统计数据,针对高炉煤气C_(C)推荐值修正前后高炉本体碳排放计算结果进行对比分析,修正前高炉本体每吨铁的碳排放量-0.19 t,修正后高炉本体每吨铁的碳排放量0.415 t,修正结果与真实碳排放情况较吻合。研究结果表明,在计算钢铁工业高炉本体二氧化碳排放时,使用实测均值、修正系数w(CO)[w(CO)+w(CO_(2))]和w(CO)—C_(com)拟合曲线修正高炉煤气单位热值含碳量,计算结果与实际相符。

The carbon emission accounting method of the iron and steel industry is based on the emission factor method provided by GB/T 32151.5-2015 Greenhouse gas emissions accounting and reporting requirements-Part 5:Steel production enterprises.The carbon content per unit calorific value(C_(C)),as an index to characterize the carbon content of combustible substances per unit calorific value,is an important influencing factor for calculating carbon emissions by emission factor method.Previous studies on carbon emissions in the iron and steel industry mainly focused on the differences between various accounting methods,but there are few studies on the accuracy of the recommended value of carbon content per unit calorific value.In order to study the influence of the carbon content per unit calorific value of combustible substances on the calculation of carbon emissions of blast furnace gas,a by-product gas of ironmaking process in the iron and steel industry was selected as the research object,and the measured values of blast furnace gas C_(C)under different components(CO and CO_(2))were calculated based on the measured data of various indicators of blast furnace gas in a steel mill.The changes of measured parameters such as the measured calorific value of blast furnace gas at low level,the measured value of C_(C)of total carbon component,and the measured value of C_(C)in combustion process were analyzed.Combined with the current situation of the widespread application of the emission factor method,based on the fluctuation of the measured value of C_(C),three methods for correcting the recommended value of C_(C)to C_(C)in the combustion process were proposed.The deviation between the corrected value and the measured value under their respective applicable conditions,was less than 5%.Finally,the relevant statistical data of the blast furnace ironmaking process of the steel mill in 2021 was used.The calculation results of the carbon emissions of the blast furnace body before and after the correction of the C_(C)recommended value of blast furnace gas were compared and analyzed.The carbon emissions of the blast furnace body before the correction were-0.19 tons of CO_(2)for every tons of iron,and the carbon emissions of the blast furnace body were 0.415 tons of CO_(2)for every tons of iron after the correction,which was consistent with the real carbon emissions.The results show that when calculating the carbon dioxide emissions of blast furnace in the iron and steel industry,the carbon content per unit calorific value of blast furnace gas is corrected by using the measured mean,the correction coefficient w(CO)/[w(CO)+w(CO_(2))]and w(CO)-C_(com) fitting curve,and the calculation results are consistent with the actual results.