钢铁工业排放颗粒物中碳组分的特征

为探究钢铁工业排放颗粒物中碳组分的特征,使用荷电低压颗粒物撞击器(ELPI)采样,采集到3组不同载荷和除污设施的烧结炉和1组炼铁高炉排放的颗粒物样品,利用热-光反射法,分析颗粒物中的有机碳(OC)和元素碳(EC)以及按温度划分的7种碳组分物质.结果表明,烧结工艺排放颗粒物中OC的质量分数高于炼铁工艺,OC在PM_(10)和PM_(2.5)质量分数分别是(5.3±2.3)%和(7.1±3.0)%,说明OC易在细粒径段颗粒富集,炼铁工艺排放颗粒物中OC在PM_(10)和PM_(2.5)质量分数分别是2.5%和2.0%;4组样品的7种碳组分相对比例相似,OC2和OC3在7种碳组分中质量分数最高,EC1、EC2、EC3的质量分数依次递减,OC1的质量分数可能与锅炉规模和脱硫设施有关;另外,烧结工艺排放各粒径段的颗粒物中OC和EC表现出较高的相关性,一次排放的PM_(2.5)中的OC/EC为4.7±0.7,远高于受体中估算二次碳组分的指标值.钢铁工业排放颗粒物中碳质组分的深入分析,可以为受体碳质气溶胶的来源解析提供基础数据,也有助于钢铁工业后续的除污管理.

Characteristics Research on Carbonaceous Component of Particulate Matter Emitted from Iron and Steel Industry

In order to investigate the carbonaceous characteristics of particles emitted from the iron and steel industry, an electrical low-pressure impactor (ELPI) was used to collect three sets of samples from the sintering process and one set of samples from the ironmaking process emissions of particulate matters. Organic carbon (OC) and elemental carbon (EC), which were divided into seven carbonaceous components based on the temperature of the particulate matter, were analyzed using a thermal-light reflection method. Results show that OC in sintering process particles is higher than that in ironmaking particles and accounts for 5.3%±2.3% and 7.1%±3.0% of PM₁₀ and PM_2.5, respectively, which reveals that OC tended to be enriched in fine particles. In the ironmaking process particles, OC accounted for 2.5% and 2.0% of PM₁₀ and PM_2.5, respectively. The relative proportions of the seven carbonaceous components in the four sets of samples were very similar. OC2 and OC3 accounted for the highest proportion; the EC1, EC2, and EC3 contents decreased in turn; and OC1 may be associated with boiler scale and desulfurization. In addition, the OC and EC of sintering process particles had higher correlation, and the OC/EC value of primary emission particles was 4.7±0.7, which is much higher than the value of the secondary OC estimation index in environment. Analyzing deeply on the carbonaceous characteristics in particles emitted from the iron and steel industry, which will provide essential data for source apportionment of carbonaceous aerosols in environment and will be conducive to the follow supervisory of pollution cleaning in iron and steel industry.