Interpretation of Emission Standard of Air Pollutants for Gas Stations (GB20952—2020)

　　Recently, the Ministry of Ecology and Environment and the State Administration of Market Supervision jointly issued the Emission Standard of Air Pollutants for Gas Stations (GB20952—2020).

　　First, the necessity and background of standard revision?

　　Since the implementation of the Emission Standard of Air Pollutants for Gas Stations (GB 20952—2007) in 2007, oil and gas pollution control in gas stations has been carried out in various places in accordance with the requirements of the standard, and positive progress has been made, which has promoted the progress of industrial production technology and pollution prevention technology and played an important role in the control of volatile organic compounds (VOCs) in gas stations. However, with the change of energy policy and the in-depth implementation of standards, some problems stand out:

　　First, the scope of application is incomplete. The original standard stipulates that the scope of application is gasoline filling stations. With the continuous deepening of China’s energy structure adjustment, many provinces have promoted the use of ethanol gasoline for vehicles. In addition, Shaanxi, Shanxi, Zhejiang, Henan and other provinces have introduced local standards to supply methanol gasoline for vehicles on a pilot basis. It is necessary to adjust the scope of application according to the actual situation.

　　Second, some on-line monitoring technical requirements are difficult to operate. The monitoring requirements of the original standard online monitoring system, such as tightness and pipeline liquid resistance, are generally reflected by instrument manufacturers at home and abroad as difficult to achieve; The original standard lacks the performance index requirements of on-line monitoring system equipment components, and the pressure monitoring equipment, flow monitoring equipment and concentration monitoring equipment have not put forward specific performance indexes of range and accuracy. Therefore, it is necessary to enrich and improve the technical requirements of online monitoring system.

　　Third, the necessity of installation of oil and gas treatment devices is controversial. In the practice of gas station pollution prevention and control, oil sales companies and some local eco-environmental management departments believe that the main scheme of gas station oil and gas pollution control is closed recovery rather than oil and gas treatment, and the oil and gas treatment device in oil storage depot is obviously superior to gas station in treatment scale, treatment capacity and energy consumption. Poor management of post-treatment device in gas station is actually equivalent to the discharge port, which has additional emission risk. Therefore, it is necessary to adjust the installation requirements of oil and gas processing devices.

　　Fourth, the monitoring is difficult and the implementation effect is not optimistic. The three monitoring indexes specified in the original standard, such as pressure, liquid resistance and gas-liquid ratio, are quite different from the conventional pollutant concentration monitoring, and the testing process requires professional explosion-proof operation and accessories, which is dangerous to some extent. Except for some key areas, law enforcement is generally insufficient, which leads to a great reduction in the implementation effect of standards.

　　A series of documents recently implemented in China, such as the Three-year Action Plan to Win the Blue Sky Defence War, the Action Plan to Combat Pollution of Diesel Trucks, the Comprehensive Control Plan for Volatile Organic Compounds in Key Industries, and the Tackling Plan for Combating Volatile Organic Compounds in 2020, all propose to strengthen VOCs pollution control in oil storage, transportation and sales. In order to further promote the emission reduction of VOCs in gas stations, it is necessary to revise and improve the existing standards reflected by industries and localities, improve the feasibility, pertinence, scientificity and legality of the standards, and at the same time implement the requirements of the CPC Central Committee and the State Council on precise pollution control, scientific pollution control and pollution control according to law, so as to improve the enthusiasm of enterprises for pollution control.

　　This revision mainly considers the relevant suggestions of oil sales enterprises on VOCs emission control in gas stations and the operability of supervision by local ecological and environmental authorities, and adds some control requirements and emission monitoring items, which is beneficial for enterprises to understand the specific technical requirements of VOCs emission control, strengthen self-management and promote the further emission reduction of VOCs in gas stations.

　　(A) expanded the scope of application

　　The original standard stipulated the limits of gasoline oil and gas emission, control technical requirements and detection methods. This revision also included ethanol gasoline sold by gas stations and methanol gasoline below M30 into the scope of control, and stipulated the requirements of oil and gas emission control, monitoring and supervision and management in the process of gasoline unloading, storage and refueling.

　　(B) Further clarified the control requirements.

　　This revision puts forward specific operating procedures for oil and gas emission control in the unloading stage; The requirements of oil and gas emission control in the oil storage stage and refueling stage are extended to all gas stations, and it is proposed that there should be no oil and gas leakage when detecting the closed point of the oil and gas recovery system by infrared camera, and the requirements of closed recovery of condensate from the accumulator are put forward for the oil and gas recovery pipeline. Clarify the index requirements of online monitoring system; Adjust the installation requirements of oil and gas treatment devices; According to the operation characteristics of oil and gas recovery system in gas station, the detection method and process are modified and refined.

　　(C) Increased atmospheric environmental monitoring projects.

　　In this revision, in order to effectively measure the sealing condition of gas station oil and gas recovery system, according to the relevant limit provisions in the original oil storage standard and referring to the Control Standard for Unorganized Emission of Volatile Organic Compounds (GB 37822—2019), the oil and gas leakage emission limit value of gas station oil and gas recovery system is added; According to the relevant requirements in Integrated Emission Standard of Air Pollutants (GB16297—1996) and Technical Specification for Application and Issuance of Pollutant Discharge Permit (HJ 1118—2020), the unorganized emission limit of VOCs at enterprise boundary was added.

　　(D) Strengthened enterprise self-monitoring requirements.

　　This revision clearly requires enterprises to establish an oil and gas recovery system, maintenance and repair management ledger, and design, build and maintain sampling ports or sampling test platforms in accordance with the requirements of environmental monitoring management regulations and technical specifications. In this revision, a separate section "Monitoring of Air Pollutants" was set up in the standard to clarify the relevant monitoring frequency and indicators, and the criteria for judging the over-standard were added, which was beneficial for enterprises to carry out relevant monitoring.

　　Third, the impact of standard implementation on the industry?

　　This revision takes into account the principles of scientificity and feasibility, without further tightening the technical requirements of emission control. It changes the mandatory installation requirements of oil and gas treatment devices in the original standard to optional, and adds the leakage limit of unorganized emissions. On the basis of strictly controlling VOCs emissions, it improves the flexibility of gas station enterprises to independently select oil and gas recovery control devices. This revision mainly puts forward requirements from the aspects of strengthening the operation details of VOCs emission control and strengthening independent monitoring, which is beneficial for enterprises to strengthen the organized and unorganized emission control of VOCs in gas stations and improve the management level, thus promoting the effective emission reduction of VOCs in gas stations.

　　IV. Environmental benefits after the implementation of the standards?

　　According to estimates, after the implementation of the standard, VOCs emissions will be reduced by 123,000 tons per year, and the saved oil products will generate economic benefits of 860 million yuan. While reducing gas station emissions and improving atmospheric environmental quality, it can promote the green, low-carbon and high-quality development of the industry and achieve a win-win situation of environmental benefits and economic benefits.