研究了典型炼化企业污水处理厂VOCs排放现状及治理技术和改造状况,针对500 m³/h炼化污水处理厂,VOCs废气排放量约35 000 m³/h,不同装置VOCs排放浓度差别明显,低浓度废气平均为200 mg/m³,高浓度废气平均为2 600 mg/m³。针对此类VOCs排放,采用吸附-冷凝预处理加生物氧化的治理工艺存在冷凝效率低、投资运行成本高等问题。结合炼化企业生产工艺特点,将低浓度废气浓缩后与高浓度废气混合通入炼化装置加热炉进行焚烧处理具有可行性,可显著降低设备投资及运行成本,改造结果显示VOCs去除率大于99%,年节约成本200余万元。

Current situation of VOCs emissions,VOCs treatment technology and technology transformation in sewage treatment plant of typical refining and chemical company is studied.As for a 500 m³·h^-1 sewage treatment plant of a refining and chemical company,VOCs emission is about 35 000 Nm³·h^-1.VOCs emission characteristics of different plants are obviously different,the average concentration of VOCs in low-concentration waste gas is 200 mg·Nm^-3,and that in high concentration waste gas is 2 600 mg·Nm^-3.For such VOCs emissions,the treatment process employing adsorption-condensation pretreatment and biological treatment technology suffers problems of low condensation efficiency,and high investment and operation cost.Combined with the production process characteristics in refining and chemical company,it is feasible to preconcentrate the low VOCs concentration waste gas,and then mix it with the high VOCs concentration waste gas together into the heating furnace for incineration treatment,which can significantly reduce the equipment investment and operation cost.Actual transformation results show that the removal rate of VOCs exceeds 99% and the annual cost is saved by more than RMB2 million.