无烟煤冶炼碳化硅废气排放规律研究

Study on emission law of anthracite smelting of silicon carbide

我国碳化硅(SiC)产能世界第一,但因冶炼方式粗放、行业排放标准缺失等原因,废气大量无组织排放,造成大气环境严重污染。使用半密闭收集装置,将废气由无组织排放变为有组织排放,继而研究其污染因子及排放规律。通过现场实测、标准比对等方法,确定污染因子为SO2、NOx、PM 3种常规污染因子和CO 1种特征污染因子。结果表明,SO2、NOx、PM的日排放量变化规律与冶炼温度存在趋同性;SO2、NOx、PM的日排放量在恒温阶段(高温段)最高,分别达439.00、59.04、38.81 kg/d。CO因同时受主副反应竞争性影响,其日排放量在升温和降温阶段较高,达6488.37 kg/d;在恒温阶段较低,为1203.70 kg/d。根据污染物日排放量,通过变频控制风机风量和吸收液流速,使之适配不同冶炼时期的污染物浓度,从而降低污染治理成本。

China's silicon carbide(SiC)production capacity ranks first in the world.However,due to the extensive unchanged smelting methods and the lack of industrial emission standards,a large amount of unorganized waste gas was exhausted,causing serious air pollution.The semi-closed collection device was used to convert the unorganized exhaust gas into organized emissions,which could be used to study its pollution factors and emission rules.Through on-site test,standard comparison and other methods,the main pollution factors in the industry were determined as three conventional pollution factors(SO2,NOx,PM)and one characteristic pollution factor(CO).The result of research showed that the daily emission variation of SO2,NOx and PM was similar to that of the smelting temperature.The daily emissions of SO2,NOx and PM was 439.00,59.04 and 38.81 kg/d,respectively,in the constant temperature stage(high temperature stage).However,CO was affected by the competitive effects of main and side reactions at the same time,and thus its daily emission was higher in the heating and cooling stages,reaching 6488.37 kg/d,but lower in the constant temperature stage,reaching 1203.70 kg/d.According to the change of daily emission,the wind volume of fan and the velocity of absorption liquid could be controlled by frequency conversion to adapt to the pollution concentrations in different smelting periods,so as to reduce the cost of pollution control.