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工业污染是城市环境污染的主要来源之一。由工业生产引发的高污染问题导致我国尘肺病发病率常年居高不下[1]。毒理学和流行病学研究表明,由工艺产生的不同粒径颗粒物对人体的危害程度不同:2.5~10 μm的颗粒能够进入上呼吸道;小于2.5 μm的颗粒可以穿透人体呼吸道的防御毛发状结构进入人体内部,对心血管系统产生毒性作用[2-4]。
在钢铁工业中,颗粒物污染源包括燃煤发电、烧结、炼铁和热轧等生产工艺[5]。目前,关于工业污染的研究场所主要集中在燃煤源、烧结和炼铁源,其污染特征研究相对成熟[6-10],而对热轧厂各工艺的关注比较缺乏,其研究重点主要在颗粒物的主要成分及元素组成上[11-13]。精轧作为热轧工艺的主要工序之一,具有高温、高污染等特点,作业人员长期暴露在颗粒污染环境中,健康风险巨大。因此,对精轧工艺微观形貌、粒径分布等特征进行进一步研究十分必要。
本研究选取典型热轧厂房精轧区进行采样实验及现场实测,对精轧工艺污染源颗粒物特征及其岗位环境污染规律进行分析。建立精轧工艺污染源颗粒物的Rosin-Rammler粒径分布函数,反映颗粒物产生源处的粒径分布特征,为进行净化除尘数值模拟研究提供参考依据;并通过岗位环境颗粒物实测得到精轧区颗粒物的动态变化特征以及空间分布规律,该规律对精轧区排风罩设计具有一定的指导意义。
精轧工艺颗粒物污染特征及其岗位环境浓度监测
Pollution characteristics of the generated particles during finishing rolling process and concentration monitoring in the occupied zone
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摘要: 为探究我国钢铁行业热轧厂精轧工艺的污染特征,利用扫描电镜(SEM)和激光粒度分布测定实验以及现场实测,于2019年夏季对广东省某典型热轧厂精轧工艺颗粒物进行微观形貌、粒径分布及其岗位环境污染规律研究。结果表明,精轧工艺所产颗粒物外观呈不规则块状形态,粒径集中在2.423~3.519 μm,其Rosin-Rammler粒径分布函数的均匀度指数为1.769,特征尺寸为2.932 μm。该结果为精轧工艺进行净化除尘数值模拟分析奠定了基础;其岗位环境颗粒物浓度随时间呈周期性波动变化,精轧区测点浓度沿轧制方向逐架递增,PM2.5/PM10均值比例依次为0.807、0.749、0.912,侧面反映了精轧源的污染特性。在精轧区排风罩设计中,建议沿轧制方向,每架精轧机排风罩的设计风量依次增大,达到精准控制局部环境的效果。Abstract: In order to explore the pollution characteristics of finishing rolling process in hot rolling mill of the iron and steel industry in China, SEM, laser particle size distribution test and field measurement were used to study the micro morphology, particle size distribution and pollution property of the occupied zone during the finishing rolling process in hot rolling mill of Guangdong province in Summer of 2019, respectively. The results showed that the particles produced by the finishing rolling process had irregular morphology and conglomeration. The particle size was mainly within the range of 2.423~3.519 μm, the uniformity index of the Rosin-Rammler distribution was 1.769, and the characteristic size was 2.932 μm. The results laied a foundation for the numerical simulation and analysis of the cleaning and dust removal of the finishing rolling process. The environmental particle concentration in the occupied zone fluctuated periodically over time. The aforementioned concentration of the environmental measuring points in the finishing rolling zone showed an increasing trend along the rolling direction, and the average concentration ratio of PM2.5/PM10 were 0.807, 0.749 and 0.912 in turn, which indirectly reflected the pollution characteristics of finishing rolling source. Thus, it is suggested that along the rolling direction, the designing ventilation flow rate should be enlarged for each exhaust hood in sequence, so as to achieve the precise control of local environment quality.
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Key words:
- finishing rolling process /
- particle /
- pollution source /
- occupied zone /
- dust removal
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表 1 精轧工艺岗位环境温湿度及PM1.0、PM2.5、PM10之间的相关分析
Table 1. Correlation analysis between the temperature, humidity and PM1.0, PM2.5 and PM10 in the occupied zone
颗粒物 温度(T) 相对湿度(φ) PM2.5 PM10 r P N r P N r P N r P N PM1.0 0.241 0.000* 443 −0.241 0.000* 443 0.988 0.000* 475 0.978 0.000* 475 PM2.5 0.285 0.000* 443 −0.279 0.000* 443 — — — 0.996 0.000* 475 PM10 0.273 0.000* 443 −0.261 0.000* 443 — — — — — — 注:r为Pearson的相关系数;P为显著性水平;N为样本数;*表示在0.05水平(双侧)上显著相关。 -
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