Discussion on integrated management and control of

2022-08-07
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Discussion on the comprehensive management and control of volatile organic compounds in the petrochemical industry

in view of the fact that the control of volatile organic compounds (VOCs) has become a hot issue in the field of atmospheric environment control in China in recent years, this paper combs the document requirements for the comprehensive management and control of VOCs in the petrochemical industry in China, analyzes the current situation of the comprehensive management of VOCs in the petrochemical industry in China, and summarizes the main existing problems. Finally, suggestions are put forward to accelerate the improvement of the top-level design system and strengthen the training of environmental protection personnel to improve the comprehensive management and control ability of VOCs

in recent years, ozone and fine particulate matter (PM2.5) in the atmospheric environment are one of the main culprits causing the current heavily polluted weather. Under UV irradiation, nitrogen oxides (NOx) and some VOCs and other substances cause the accumulation of ozone in the air through a series of photochemical reactions. The photochemical activity of these VOCs mainly has two indicators, namely, the constant value of hydroxyl radical reaction rate KOH and the maximum incremental activity indicator Mir. In addition to photochemical activity, some VOCs also have toxic and harmful properties; A few VOCs have the characteristics of destroying stratospheric ozone and greenhouse gases; Benzene, toluene, xylene and other substances have photochemical reaction and toxic and harmful properties at the same time

vocs comprehensive management and control has become a hot issue of air pollution control in China. The petrochemical industry is one of the key industries for VOCs emission control. In addition, the emission characteristics are mainly unorganized emissions, the industry process is cumbersome, involving many source items, complex components, unclear real composition, and insufficient control capacity for the whole process refinement. Compared with other industries, the comprehensive control of VOCs in the petrochemical industry needs higher cognitive ability and system technical support

this paper combs the national control requirements of VOCs in the petrochemical industry, and summarizes the current situation of comprehensive control of VOCs in the petrochemical industry in China. Based on the VOCs remediation results of key sample survey enterprises, this paper analyzes the main problems, and puts forward targeted countermeasures and suggestions for the comprehensive VOCs management and control of enterprises and environmental protection management departments during the 13th Five Year Plan period

VOCs control requirements in petrochemical industry

relevant standards

at present, there are 35 standards involving VOCs in China, including monitoring method standards, quality standards, emission standards, etc; There are 16 accounting methods, involving petrochemical industry, printing industry, automobile manufacturing (coating) and other industries; There are 4 charging methods; There are four local management measures, including the guidance on VOCs Pollution Control and the acceptance measures for VOCs Pollution Remediation

relevant policy documents

in the 12th Five Year Plan for the prevention and control of air pollution in key areas issued and implemented by China in 2012, VOCs, sulfur dioxide (SO2), NOx and industrial smoke and dust are listed as the key prevention and control objects in the three zones and ten groups of key areas, the emission reduction targets of active sources in key industries are determined, and the governance of key industries is required, in which it is clear that VOCs emissions from the petrochemical industry should be vigorously reduced. Subsequently, the state and local governments successively issued a series of VOCs control policies, and so far there are about 26 relevant documents. Requirements have been put forward in the emission accounting, measures and requirements, control methods and other aspects of VOCs in the petrochemical industry. For example, the comprehensive treatment plan for volatile organic compounds in the petrochemical industry clearly proposes to carry out a thorough investigation of volatile organic compounds; Fully implement LDAR (leakage detection and repair) technology; All organic liquid storage facilities shall adopt highly efficient sealed floating roof tanks, or install oil and gas recovery facilities; The waste water system shall be covered and sealed; Organic waste gas shall be recycled first. If it cannot be recycled, it shall be effectively treated by incineration; Strengthen supervision and management, and implement the requirements of VOCs Pollution Control in the whole process

current situation of VOCs comprehensive renovation in the petrochemical industry

according to the statistical data of the Federation of petroleum and chemical industries, in 2015, there were 29765 Enterprises above Designated Size in China's petroleum and chemical industry. In 2015, the main business income of the whole industry reached 13.35 trillion yuan, an increase of 58.8% over 2010; The total tax amount reached 1.03 trillion yuan, accounting for about 21% of the national industrial tax, ranking first in the industrial industry; Oil production, natural gas production and crude oil processing volume respectively ranked fourth, sixth and second in the world in 2017

according to the current situation of VOCs control in the petrochemical industry, large enterprises in key areas such as Jinling Petrochemical, Huizhou refining and chemical, Dagang Petrochemical, etc. have carried out VOCs control. According to the relevant requirements of the comprehensive treatment plan for volatile organic compounds in the petrochemical industry, the total emission of VOCs in the petrochemical industry in 2017 should be reduced by more than 30% compared with that in 2014. From 2015 to 2016, all provinces (cities and autonomous regions) formulated the work plan, implementation plan, treatment plan or implementation rules for the comprehensive treatment of VOCs according to the treatment plan, and carried out the comprehensive treatment of VOCs in petrochemical enterprises. Generally speaking, the comprehensive treatment of VOCs in the petrochemical industry in all provinces (cities, autonomous regions) is being carried out in an orderly manner, but there are still some problems in the implementation process

according to the unified arrangement of the atmospheric Department of the Ministry of environmental protection, the working team carried out on-site investigation on typical petrochemical enterprises, and estimated the VOCs emission level of China's petrochemical industry according to the accounting results and analogy calculation. By the end of 2015, China's oil refining capacity was about 797million tons/year, and its ethylene production capacity was about 17million tons. According to the VOCs emissions of research enterprises, it is estimated that the VOCs emissions of China's oil refining industry and ethylene production industry were about 549900 tons/year and 15000 tons/year respectively. Due to the representativeness of the selected enterprises and the accuracy of the basic data, there will be a certain degree of deviation between the estimated data and the real situation

main problems in the comprehensive treatment of VOCs in the petrochemical industry

in the past three years, the vast majority of the petrochemical industry has carried out many forms of comprehensive treatment of VOCs. Up to now, the treatment results are still different from the requirements of the comprehensive treatment plan for volatile organic compounds in the petrochemical industry. For example, the base amount of VOCs emissions has not been found out. Various measures have been taken, most of which are end treatment measures. When there are more furnishings, there are less practical effects. There are many people engaged in VOCs governance, but few people actually solve problems. There is a common problem that the level of cognition is not in place

the strength of China's environmental protection administrative departments is relatively weak, and it is difficult to carry out long-term effective supervision only on the pollutants discharged in an organized way. For VOCs with unorganized emissions as the main means, the traditional management mode with government supervision and on-site monitoring as the main means can no longer meet the requirements of VOCs management. According to the investigation of typical petrochemical enterprises, the main problems are discussed as follows

vocs is vaguely defined and the top-level design is imperfect.

at present, many monitoring method standards, quality standards and emission standards involving VOCs in China have not yet formed a unified VOCs definition. Most of them are defined according to the physical properties of VOCs, without considering the photochemical properties of substances, which cannot reflect the control purpose of VOCs, and is not conducive to enterprises to take targeted measures. In addition, incomplete standard coverage and inconsistent characterization and monitoring methods also make it difficult to monitor and control VOCs Pollution sources

the current law on the prevention and control of air pollution does not put forward targeted requirements for the control and emission of VOCs, resulting in the lack of necessary legal basis and basis for VOCs Pollution Control; The supporting standards are not perfect. Many industries involving VOCs have not yet formulated VOCs emission control standards, which also hinders the implementation progress of VOCs Pollution Control

the cognition level is not in place, and the systematic management and control idea has not been established.

the enterprise's VOCs management and control concept and daily management level are gradually improving and strengthening, but the relevant personnel have insufficient awareness of VOCs Pollution Management and control, and the main pollution control focus is still on terminal treatment. Enterprise decision-makers' understanding of governance technology is not systematic, and the technology actually adopted is often only a single module in the system technology, resulting in poor overall operation effect

the enterprise has some systematic problems in the daily management of VOCs, such as no LDAR management system has been established; The account mechanism is not sound, and the working status of ignition facilities and flare is not continuously recorded; The long-time torch light goes out; Some processes have organized emissions, while the sources are not counted. At present, enterprises are more concerned about how to avoid or reduce the administrative punishment imposed by the regulatory authorities on enterprises, which is not conducive to improving the competitiveness of enterprises in the international industry. Although a large amount of capital has been invested, it has not played a significant role in improving the environmental quality

incomplete identification of pollution source items, missing or incorrect accounting parameters

although most enterprises have carried out statistical work on basic information related to organized and unorganized emissions, the identification of pollution source items is not comprehensive enough, and the statistical work needs to be further refined. For example, in other production or operation processes of refining and chemical enterprises except delayed coking, there are also unorganized emission source items, but the emissions are not counted; VOCs emissions during the loading and unloading of intermediate products are not counted; The turnover of storage tanks does not take into account the turnover of tanks, and some solvent storage tanks are not included in the accounting scope; The discharge of sampling process and wastewater collection system is not accounted; The wastewater is accounted by the discharge coefficient method, without deducting the emission of VOCs removed by the implementation of pollution control

some enterprises did not monitor and record the flow of combustion flue gas, the flow and composition of flare gas and other parameters. The lack of important parameters such as Reid vapor pressure, distillate temperature, disk gap factor, etc. required for VOCs emission accounting of storage tanks will lead to great differences between the accounting results and the actual situation. Taking the Reid vapor pressure and distillation temperature parameters of cracked naphtha storage tank as an example, if there are no corresponding oil parameters, the default is the light naphtha data. The real vapor pressure at 17 ℃ is 57.5kpa, and the edge sealing loss of the corresponding inner floating roof tank is 2.8 tons/year. If the Reid vapor pressure of 43.6kpa and the corresponding distillation temperature are substituted, the real vapor pressure at 17 ℃ is 22.9kpa, and the corresponding loss is 0.9 tons/year. The former is 3.1 times of the latter

since 2017,

some enterprises have not established LDAR standing books. The types and quantities of sealing points based on preliminary statistics are not comprehensive, and can not fully reflect the emission of VOCs leaked from the dynamic and static sealing points of equipment. Or the establishment of LDAR account is inconsistent with relevant requirements, for example, the statistical sealing points cannot include the controlled sealing points of the whole plant, the valve is divided into two sealing points, gland and packing, ethylene glycol is identified as light liquid, and the inaccessible points are not counted

the treatment measures do not meet the requirements, and the operation effect is not ideal.

the cleaner production level of most enterprises needs to be improved. If the organic liquid storage is not equipped with oil and gas recovery facilities; Closed facilities are not adopted for sewage collection and transmission, and some facilities are covered for collection, but the air tightness needs to be strengthened; Some organic liquids are still loaded by splashing; The intermediate products and products are discharged during loading and unloading, resulting in environmental pollution in the plant area

take the oil and gas recovery facilities installed on the truck as an example. Although they are in operation all year round, it is found that materials have not been recovered or few materials have been recovered, and the overall control efficiency using collection efficiency, removal efficiency and facility utilization rate as statistical means is very low. According to the data of on-site monitoring and investigation, the organic liquid loading process of a petrochemical enterprise uses oil and gas collection to recover and reduce the emission of oil and gas. Through the comparison of the oil and gas concentration values at the inlet and outlet of the end treatment measures, it is concluded that the removal efficiency is about 96%. However, the comprehensive removal efficiency of oil and gas of the treatment measures is only 3.34% - 5.56% through the calculation of gasoline recovery and theoretical gasoline volatilization. The main reason for this result is that although the gasoline recovery facility itself has a high removal efficiency of 96% for the collected oil and gas, the actual collection efficiency is about 5%, and 95% of the oil and gas is discharged into the

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