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Emission coefficient of exhaust pollutants in the production of rubber products

2019-05-27

With the continuous growth of domestic automotive consumer market demand, the automotive industry is developing rapidly. The rubber processing industry supplies automotive manufacturers with rubber products such as tires, hoses, tapes, oil seals, seals, shock absorbers, cups, dust covers and fenders. On average, there are 400-500 rubber parts per car, accounting for 4%-5% of the car's own quality. Therefore, as an upstream industry closely related to the automobile manufacturing industry, the rubber products industry is also in a stage of overall development.


In the production process of rubber products, a large amount of organic waste gas such as carbon disulfide and non-methane total hydrocarbons will be generated, which seriously affects the atmospheric environment. In recent years, various environmental pollution incidents have occurred one after another. The public has higher and higher requirements for environmental protection and environmental satisfaction of enterprises involved in pollutant discharge, and it is surrounding the problem of rubber odor and odor around the rubber products enterprises. Complaints and relocation opinions are not uncommon. To this end, the United Nations General Administration of Quality Supervision, Inspection and Quarantine of the Ministry of Environmental Protection issued the GB27632-2011 "Emission Standards for Pollutants in the Rubber Products Industry" in October 2011, and formulated strict emission standards for pollutants produced by rubber products enterprises. The standard was implemented on January 1, 2012.


The exhaust gas components produced by the rubber products industry are extremely complex, and nearly 100 kinds of pollutants are emitted. In addition to the emission of particulate matter, there are few reports on the in-depth study of organic waste gas emitted from various rubber production processes in China, which has led to the lack of theoretical and practical basis for the calculation of the source of exhaust gas in the environmental impact assessment stage of rubber product manufacturers. The local environmental management department has brought a series of problems to the follow-up environmental supervision of rubber products enterprises.


This paper mainly introduces the emission coefficient of various types of exhaust pollutants obtained by the American Rubber Manufacturers Association (RMA) for testing various rubber raw materials or tire components in the rubber product production process, and analyzes its applicability in accordance with the requirements of domestic standards, with a view to making an environmental impact assessment. The organization provides reference for calculating the pollution source and taking necessary control measures, and also provides relevant technical support for the daily approval and supervision of the environmental protection department.


1 test object


The rubber products for RMA testing are divided into 31 categories. The products are classified into rubber parts and tires as main parts, as shown in Table 1. Common raw materials for testing include: natural rubber (NR), bromobutyl rubber (BIIR), butadiene rubber (BR), styrene butadiene rubber (SBR), butyl rubber (IIR), ethylene propylene diene monomer (EPDM), Neoprene (CR), chlorosulfonated polyethylene rubber (CSM), fluororubber (FKM), ethylene methyl acrylate rubber (AEM), hydrogenated nitrile rubber (HNBR), silicone rubber (MVQ), acrylate rubber ( ACM), chlorinated polyethylene rubber (CM), chloroether rubber (ECO) and polyvinyl chloride (PVC).


31 types of rubber products basically cover the raw materials produced by American rubber companies. Compared with domestic rubber products companies, the overall difference is not obvious; the difference is that domestic rubber enterprises will use more recycled rubber instead of some rubber to reduce Cost of production.


2 test production process


The rubber product production process mainly includes mixing, extrusion, calendering, vulcanization and trimming. Vulcanization can be subdivided into flat vulcanization, vulcanization vulcanization, hot press vulcanization, and tire vulcanization. In addition, tire vulcanization mainly tested 4 different types of tires; trimming and grinding mainly tested the exhaust gas emitted from the tire belt, carcass, retreaded tires and sidewall rubber or white sidewall trimming. RMA has tested a total of nine rubber processing steps, corresponding to the test rubber or tire components.


3 test results


The emission coefficient in the test results is expressed by the mass of pollutants discharged from the rubber raw materials consumed. The US Environmental Protection Agency uses imperial units for the emission factor. This article is expressed in terms of general and domestic practices as mg ̇ kg-1.


In addition, due to the dozens of types of pollutants produced in each production process, the necessary screening of pollutant types is carried out according to the current domestic standards, focusing on volatile organic compounds (VOCs), particulate matter, and non-methane. Total hydrocarbons, heavy metals, harmful exhaust pollutants (HAP) and carbon disulfide were counted.


The particle emission coefficient in the mixing and trimming process is relatively large, and the particle emission coefficient in the extrusion process is relatively small, almost negligible; the heavy metal HAP emission coefficient in the mixing and extrusion process is small, repair The heavy metal HAP emission coefficient in the grinding process is relatively large; VOCs are the main source of odor and odor around the rubber product manufacturing enterprises, which exist in the whole rubber product production process, and the VOCs emission coefficient is relatively small in the calendering and extrusion processes. The VOCs emission coefficient in vulcanization, hot roll mastication, mixing and trimming and grinding processes is very large; the emission coefficient of non-methane total hydrocarbons in calendering, extrusion and hot roll plasticating processes is not large, in mixing, vulcanization and repair The non-methane total hydrocarbon emission coefficient in the grinding process is relatively large; the carbon disulfide emission coefficient in the calendering, extrusion, hot roll and tire vulcanization processes is relatively small, and the vulcanization, mixing and trimming processes are affected by different test objects, carbon disulfide The difference in emission factors is quite obvious, and the emission coefficients between different rubber types or tire components often differ by several orders of magnitude.


In general, the mixing, vulcanization and trimming and grinding processes in the rubber product industry are the key pollution-producing processes. The main pollutants are VOCs, non-methane total hydrocarbons and particulate matter, which should be analyzed for universality; The carbon dioxide emission coefficient of raw material testing varies greatly. It should be analyzed according to the actual raw materials used. The overall emission coefficient of heavy metal HAP is small, which can be identified and analyzed according to specific procedures.


In addition, in the aspect of pollution prevention and control, the whole process control of VOCs generated in the rubber product industry production process should be carried out, and the efficiency of collection and treatment of exhaust gas should be improved through effective gas collection treatment facilities, and the odor and odor generated by VOCs emissions can be reduced to the surrounding environment. influences.


4 conclusion


(1) The emission coefficient of VOCs generated during the production of rubber products is very large, and it is the main source of odor and odor in the surrounding environment. It should be controlled throughout the process, and reduce the odor and odor generated by VOCs emissions by improving the efficiency of collection and treatment. The impact of the surrounding environment; VOCs should be included in the total control area as a characteristic pollution factor of the rubber products industry.


(2) The mixing, vulcanization and trimming process in the production of rubber products is the main pollution-producing process, and key prevention and control should be carried out. The main pollutants VOCs, non-methane total hydrocarbons and particulate matter should be analyzed for universality; carbon disulfide And heavy metal HAP can be targeted for differential identification according to different raw materials or specific processes.


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