加油站油气处理装置作用及VOCs排放现状

我国GB 20952-2007《加油站大气污染物排放标准》首次提出加油站安装油气处理装置，但是部分油气回收从业人员对油气处理装置的作用存在一些认识误区.通过对美国加州加油站油气处理装置的发展历程进行回顾，阐述加油站油气处理装置的作用，并对油气处理装置VOCs(挥发性有机物)的排放现状进行全口径检测和分析.结果表明:①油气处理装置是加油站油气回收系统的重要组成部分，主要用于控制Stage Ⅰ(卸油油气回收系统或第一阶段油气回收系统)和Stage Ⅱ(加油油气回收系统或第二阶段油气回收系统)工作时埋地油罐压力增加所导致的无组织排放，但它不能取代Stage Ⅰ.②2016-2018年北京市油气处理装置NMHC(非甲烷总烃)排放浓度分别为5.43、3.67和2.30 g/m3，达标率由98.5%升至99.7%；春、夏、秋、冬四季NMHC平均排放浓度分别为3.54、4.68、3.13和1.64 g/m3，其中夏季NMHC排放浓度最高；"吸附"和"冷凝+膜"处理效果略优于"膜分离".③2017年北京市油气处理装置NMHC排放浓度相对于排放标准(≤ 20 g/m3)的达标率为97.6%，NMHC排放浓度≤ 10 g/m3的比例为90.4%.研究显示，加油站油气处理装置是埋地油罐压力控制装置，为减少油罐及其附属设施的无组织排放发挥了重要作用，值得进一步开展研究. 

Functions and Emission Status of VOCs from Vapor Processing Devices in Gasoline Filling Stations

The Emission Standard of Air Pollutant for Gasoline Filling Stations (GB 20952-2007) first stipulated that gasoline filling station should install vapor processing devices, but some worker engaged in the vapor recovery misunderstood the functions of vapor processing devices. On the basis of the review of the development history of vapor processing devices in California, USA, the functions were illustrated and the VOCs emission status of all vapor processing devices was tested and analyzed completely. The results showed that: (1) The vapor processing device was an important part of the vapor recovery system of gasoline filling station, which mainly controls the fugitive emission caused by the pressure increase in gasoline underground storage tanks during operation of StageⅠ(unloading vapor recovery system or Stage Ⅰ of vapor recovery system) and Stage Ⅱ (refueling vapor recovery system or Stage Ⅱ of vapor recovery system). But it can't replace Stage I. (2) The NMHC emission concentrations of the vapor processing devices were 5.43, 3.67 and 2.30 g/m3 from 2016 to 2018 in Beijing, respectively, and the compliance rate rose from 98.5% to 99.7%. The average emission concentration of NMHC was 3.54, 4.68, 3.13 and 1.64 g/m3 in spring, summer, autumn and winter, respectively. It was the highest in summer. The treatment effect of 'adsorption' and 'condensation and membrane combination process' was better than that of 'membrane separation'. (3) The compliance rate of NMHC emission concentration relative to the emission standard (≤ 20 g/m3) was 97.6%, and the proportion of NMHC emission concentration less than 10 g/m3 was 90.4%. Studies have shown that the vapor processing device is worthy of further research, for controlling the pressure of the underground storage tanks, and plays an important role in reducing the fugitive emission of the tanks and its ancillary facilities.