On June 10th, Cheng Zengqiang, an operator of public works department of Lanzhou Petrochemical Company, came to sewage outfalls of oil refining unit to sample and analyze the quality of discharged wastewater. The analysis results show that the standard rate of discharged wastewater reaches 100%. "Our effluent can be used to raise fish." Cheng Qiang told reporters.

Lanzhou Petrochemical Company, located in the upper reaches of the Yellow River, anchored the goal of "double carbon", comprehensively promoted clean production, intensified pollution prevention and control, accelerated the transformation of green and low carbon, and actively built a safe, green and low carbon city-type refining and chemical enterprise. In recent years, the company has invested 1.467 billion yuan to complete 119 environmental protection projects around the upgrading of new environmental protection standards and VOCs control and management, and the rate of effluent reaching the standard reached 100%, making important contributions to protecting the ecology of the Yellow River Basin.

Perfecting system and mechanism and strengthening monitoring and supervision

Drinking the Yellow River water, thinking about the downstream people. This is one of the environmental protection concepts of Lanzhou Petrochemical. Combining with the actual production, Lanzhou Petrochemical has continuously revised and improved the environmental protection management system, starting with ten systems, such as environmental protection organization guarantee, environmental risk assessment, automatic atmospheric monitoring at the factory boundary, and environmental responsibility investigation, and making every effort to create a long-term mechanism for improving environmental protection management.

Environmental protection point source "source length system" is a pioneering work of Lanzhou Petrochemical Company to strengthen emission supervision. The company sorts out the supervision responsibility of each pollution source discharge port, implements it to the main leaders of the relevant branch factories and workshops, puts up the environmental protection indicators on the wall, and sets up a sign at the discharge port to express it, strictly assesses the completion of the environmental protection indicators, urges leaders at all levels to strengthen environmental protection supervision, thoroughly inspect, analyze and rectify environmental problems, and forms a long-term mechanism for benign improvement.

Lanzhou Petrochemical Weave Dense Environmental Monitoring and Supervision Network has installed online monitoring equipment at waste water outlets and key waste gas outlets, and installed VOCs online monitoring facilities at the factory boundary, and networked with the government environmental protection department and the monitoring platform of PetroChina Headquarters to realize 24-hour monitoring and supervision. In particular, the company has strengthened the capacity building of intelligent supervision, established sewage early warning and three-level management and control mechanism, and added early warning indicators for the concentration of main pollutants at the outlet of refinery, chemical and catalyst sewage. Once the early warning value is triggered, there will be a short message prompt on the mobile phone of managers, which is convenient for timely handling of abnormal situations. At the same time, the company added an over-standard interlock switch valve at the discharge outlet of Xigu Water Park. When the discharge index triggered the early warning value, the over-standard wastewater could be automatically switched into the emergency pool within two minutes to ensure that the discharged wastewater was 100% qualified.

"We are stepping up the application of advanced emergency monitoring technologies such as drones and portable GC-MS, comprehensively using big data, remote sensing, artificial intelligence and other technologies to promote the construction of intelligent monitoring and emergency system, promote the upgrade of online monitoring system, and comprehensively improve the early warning capability of excessive emissions and the intelligent monitoring level of sewage discharge." Jianming Shen, director of Lanzhou Petrochemical Safety and Environmental Protection Division, said.

Deepen environmental governance and promote green development

Lanzhou Petrochemical has thoroughly implemented the national deployment of ecological environment management in the Yellow River Basin, established a reverse mechanism for ecological environment protection, promoted the optimization and adjustment of industrial structure and energy structure, and promoted green and low-carbon development. In wastewater treatment, the company invested 243 million yuan to complete 23 wastewater treatment projects. Especially in the upgrading project of chemical wastewater treatment plant, on the basis of the original process, the company added the process of "air flotation+ozone contact oxidation+decarbonization biological filter". After the operation, the COD, total nitrogen, chroma and SS of the discharged wastewater decreased by 46.71%, 43.41%, 87.5% and 66.77% respectively on the basis of the original standard discharge. In the construction of refinery sewage concentrated water treatment project, the company transported the biochemical refinery sewage to the refinery sewage reverse osmosis treatment unit for deep recovery treatment, which not only ensured that the discharged sewage reached the standard stably, but also improved the recycling rate of wastewater.

After the promotion of the new national environmental protection standard for waste gas emission, Lanzhou Petrochemical has implemented 21 projects of waste gas reaching the standard and hidden danger treatment. In order to recycle the waste gas from oil refining and chemical production, the company invested 433 million yuan to implement 30 VOCs treatment projects, and the emission reduction rate of VOCs reached over 60%. In recent years, the online monitoring of Lanzhou Petrochemical's on-line instrument and government monitoring platform shows that all major pollutants such as COD have achieved 100% discharge standards.

Strengthen risk management and control to realize cleaner production

Lanzhou Petrochemical Company promoted the cleaner production of oil refining business by upgrading the quality of oil products, successively completed the technological transformation of 1.8 million tons/year catalytic gasoline hydrogenation and 3 million tons/year diesel hydrogenation, and realized the "triple jump" of the quality upgrading of gasoline and diesel from China III to China IV, China V and China VI. The sulfur content in oil products continued to decrease, and the refined products gradually became cleaner. In 2021, the comprehensive energy consumption of refining in Lanzhou Petrochemical Company decreased by 1.17 kg standard oil/ton compared with the previous year, and the output of clean oil products such as high-grade gasoline, aviation gasoline and aviation kerosene increased significantly, providing more clean energy for the society.

Lanzhou Petrochemical Company continues to promote the "321" clean production project, which "completes three major tasks of solid waste reduction, waste gas emission reduction and waste water pollution reduction, ensures two controls of production operation and equipment integrity, and strives to achieve the goal of environmental friendliness according to laws and regulations". The company adheres to the ideas of source prevention, process remediation and end management, and takes environmental protection indicators as important production indicators into operation procedures and process cards, which are strictly implemented in production; Take environmental protection facilities as key production facilities, strengthen daily operation and maintenance management, ensure long-term stable operation, and effectively play the role of decontamination and emission reduction. At the same time, the company strengthened the environmental risk control of water system, strengthened the operation management of sewage treatment plant, and continuously reduced the concentration and total amount of pollutants on the basis of ensuring the stable standard; Carry out environmental risk investigation and assessment, continuously improve environmental risk prevention and control measures, establish and improve environmental risk prevention and control system and three-level prevention and control facilities, improve environmental risk prevention and control capabilities, and ensure environmental risk control.

According to the national VOCs control guidelines for key industries, Lanzhou Petrochemical has formulated detailed rules for odor control, key points for VOCs control and the VOCs control plan of "one factory, one policy", strengthened process supervision, and strived to build odor-free factories. The company has also taken measures such as closed purging to strengthen the environmental protection control of plant start-up, shutdown, inspection and maintenance, and realize green maintenance.

Lanzhou Petrochemical Company continued to carry out cleaner production audit, with 10 branches and 113 sets of production devices passing the cleaner production audit, evaluation and acceptance of local government and PetroChina Headquarters, and implementing 2,142 cleaner production schemes. Eight units, including oil refineries, were awarded Grade A environmental protection standardization enterprises. From January to May this year, the ammonia nitrogen, COD and nitrogen oxides discharged from Lanzhou Petrochemical Company decreased by 17.49%, 11.17% and 2.47% respectively, and the total amount of sewage discharged reached a new low, making contributions to improving the regional environmental quality.