摘 要随着国家对挥发性有机物（Volatile Organic Compounds，VOCs）的管控措施不断加严，作为VOCs控排重点行业的加油站企业近几年在油气回收方面面临着愈发显著的挑战。加油站卸油油气回收系统（也称为一次油气回收系统）是油气回收技术的基础核心，而它的系统气密性问题一直是行业的痛点和难点。值得关注的是，我国油气回收气液比指标采用更严格的标准，会导致油罐罐压升高，很容易在系统中密封连接处发生油气VOCs渗漏，且目前国内在此环节的标准化弱，施工质量参差不齐，造成油站VOCs过度排放。随着2020年国家颁布的加油站大气污染物排放标准中提出对密闭点位油气排放限值的要求，加油站油气排放超标的问题变得更加突出，有的加油站排放浓度甚至超过国标限值的数倍。本研究通过对目前加油站油气VOCs超标问题的调研与数据分析，识别出一次油气回收中从设计到施工中的主要问题，基于这些问题提出工厂生产预制安装的优化方案，通过实施设计标准化，实现安装构件在工厂加工、检测、预安装。优化方案在改造油站2和新建油站3实施后，以一座采用现场施工工艺的油站1为基准，利用三维评估模型对该方案进行评估，评估重点包括：1）环保性，依照国家标准评估加油站密闭点位及边界无组织VOCs排放，通过健康危险指数（Hazard Quotient，HQ）和可吸入致癌物质风险（Inhalation Cancer Risk，ICR）评估油站排放VOCs中有毒物质对人体健康的影响；2）在加油站全生命周期内的总碳排放量；3）在加油站全生命周期内的总成本。评估结果如下：采用新工艺的改造油站2和新建油站3的8个油罐的密闭点位排放浓度值在0.2 ~ 8.1 μmol/mol之间（国标限值500 μmol/mol）；两座采用新工艺油站2和3边界无组织排放浓度分别为1.94 mg/m3和0.67 mg/m3，均大幅低于排放限值 4 mg/m3；在健康危险指数的评估中，油站1的HQ值达到了0.78（HQ>1，有健康风险），油站2和油站3分别为0.012和0.004；在可吸入致癌物质风险指数ICR评估中，基准油站1指标为2.72×10-6，改造油站2为1.29 ×10-6, 处在有致癌可能性风险区间（1×10-6 ≤ICR≤1×10-5），油站3为4.72 ×10-7，远小于该数值。在生命周期中，采用新工艺油站的碳排放总量比传统工艺下降64%，总成本是旧工艺油站的22%。综上，该新工艺方案显示出很好的环保性、碳减排潜力及经济效益，并可以有力地支持加油站企业达成VOCs的减排目标。关键词：油气回收；环保性；碳排放；成本评估；全生命周期

AbstractWith the continuous tightening of national control measures for volatile organic compounds (VOCs), gas station enterprises, which are key industries for VOCs emission control, have faced more and more significant challenges in fuel vapor recovery in recent years. The vapor recovery system for unloading gasoline (also known as the Vapor Recovery stage I system) is the basic core of fuel recovery technology, and its system air tightness has always been a pain point and difficulty in the industry. It is worth noting that China‘s vapor recovery Air-liquid ratio index adopts stricter standards, which will lead to an increase in tank pressure, and it is easy to leak VOCs at the sealing connection in the system. With the requirements for VOCs emission limits at closed points in the air pollutant emission standards for gas stations promulgated by the state in 2020, the problem of VOCs emissions from gas stations has become more prominent, and the emission concentration of some gas stations even exceeds the national standard limit by several times.Through the investigation and data analysis of the current VOCs emission exceeding the standard in gas stations, this study identifies the main problems from design to construction in Vapor Recovery stage I system, proposes an optimization solution for factory production and pre-fabrication and pre-installation based on these problems, and realizes the processing, testing and pre-installation of installation components in the factory through the implementation of design standardization. After the implementation of the renovated gas station No.2 and the new gas station No.3, the optimization solution was evaluated by adopting a three-dimensional evaluation model based on a gas station No.1 using traditional on-site construction process, and the evaluation focus includes: 1) environmental protection, the VOCs emission at closed points of gas stations and unorganized VOCs emission within the boundary of gas station were assessed according to national standards, and the hazard quotient (HQ) and inhalation cancer risk (ICR) to assess the impact on human health of hazardous substances in VOCs emitted from petrol stations; 2) Carbon emissions throughout the life cycle of gas station; 3) The total cost of the whole life cycle of gas station.The evaluation results are as follows: the emission concentration values of the 8 fuel storage tanks of the renovated gas station No.2 and the new gas station No.3 using the new solution are between 0.2 ~ 8.1 μmol/mol (the national standard limit is 500 μmol/mol); The unorganized VOCs emission concentrations at the boundaries of the two new solution station No.2 and No.3 were 1.94 mg/m3 and 0.67 mg/m3, which were significantly lower than the emission limit of 4 mg/m3. In the assessment of hazard quotient, the HQ value of station No.1 reached 0.78 (HQ>1, there is a health risk), and the HQ value of station No.2 and station No.3 was 0.012 and 0.004, and in the ICR evaluation of the risk index of inhalable carcinogens, the index of benchmark station No.1 was 2.72×10-6, and the index of modified station No.2 was 1.29 ×10-6, which was in the risk range of possible risk (1×10-6 ≤ICR≤1×10-5), and the station No.3 was 4.72 ×10-7, which was much lower than this value. In the life cycle of a gas station, the total carbon emissions of the new solution station are 64% lower than that of the traditional process, and the total cost is 22% of that of the old process. In summary, the new solution shows good environmental protection, carbon emission reduction and economic benefits, and can strongly support the achievement of VOCs emission reduction goals of gas station enterprises.Keywords: Vapor Recover; Environmental Benefits; Carbon Emission; Total Cost; Life Cycle Analysis.