基于开路式傅里叶变换红外光谱仪现场实测法的污水处理单元VOCs排放核算研究

针对我国石化企业污水处理单元挥发性有机物（Volatile Organic Compounds,VOCs）排放量核算结果准确度不一、缺乏有效评估手段的现状,建立了一种基于开路式傅里叶变换红外光谱仪（Open Path-Fourier Transform Infrared Spectroscopy,OP-FTIR）现场实测的源强反算方法,并利用该方法对我国北方某石化企业污水处理单元于2018年11月进行了18 d的大气VOCs环境浓度监测,监测结果表明,研究单元VOCs排放污染物以烷烃、卤代烃、苯系物和有机硫化物为主,其体积浓度百分比可达到95%,源强反算结果表明,研究单元TVOCs年排放量约为52.61 t·a^-1,与根据生态环境部《石化行业VOCs污染源排查工作指南》计算结果较为相近,该反算方法可作为指南核算结果的一种辅助验证和评估手段而存在,气浮池、催化燃烧和污泥干化单元VOCs年排放量远远高于隔油池单元,特别是气浮池单元是VOCs减排治理的重点和难点,苯系物和甲硫醇更是其中的代表性污染物,应重点关注和加强管控.

Calculation research of VOCs in sewage treatment unit of a petroleum refinery based on OP-FTIR

In view of the current situation of the accuracy of the VOCs emission calculation, and the lack of effective evaluation methods, a source strength inversion methodology based on OP-FTIR was established to monitor the ambient concentration of VOCs in a petrochemical sewage treatment unit in northern China for 18 days in November 2018. The monitoring results show that the VOCs in the studied unit are mainly composed of alkanes, halogenated hydrocarbons, benzenes and organic sulfides, and the volumatric content can reach 95%. The results calculated by the source strength inversion method show that the annual emission of TVOCs in the research unit is about 52.61 t·a^-1, which is similar to the results calculated in the "Guidelines for VOCs Pollution Source Investigation in Petrochemical Industry" issued by Ministry of Ecology and Environment of the People''s Republic of China, and the source strength inversion method can be used as an alternative verification and evaluation tool for the guidance accounting. Next, the annual VOCs emissions of air floatation cell, catalytic combustion and sludge drying unit are much higher than those of grease trap unit. In particular, the air flotation cell unit is the key point of VOCs emission reduction control. Benzene homologues and methyl mercaptan are the representative pollutants among them. We should pay more attention and strengthen the control.