| While the pace of industrialization in our country is accelerating,the environment is also suffering severe erosion.Among them,the air pollution caused by volatile organic compounds(VOCs)is particularly significant,such as haze and photochemical smog,etc.In addition,VOCs can also pose a threat to human organs and nervous system.As the main emission source of VOCs,industrial sources have the problems of imperfect monitoring system and production technology.The“Three-year Action Plan for Winning the Blue Sky Defense War” issued by the State Council in 2018 clearly stated to: adjust and optimize the industrial structure,promote the green development of industries,and deepen the control of industrial pollution.For the prevention and control of VOCs in the industry,it should always focus on the three points of ’source reduction’,’process prevention and control’ and ’end treatment’,and take ’source reduction’ as the center to carry out.Among them,industrial cleaning often uses solvent-based cleaning agents,a large number of VOCs are discharged through non-standard channels,which puts enormous pressure on the environment.In industrial cleaning,aircraft-engine cleaning has always been a big problem in the field of aviation equipment remanufacturing.Due to its long-term service under high temperature and high pressure,the surface of the engine tends to generate a series of dirt that is difficult to remove,such as carbon deposition,glue and so on.These dirt are firmly combined with the metal matrix,and the degree of graphitization is high,which makes it very difficult to clean.Ordinary cleaning agent is difficult to play a very good effect.For the cleaning of aeroengine,gasoline,kerosene and other organic solvents are widely used in industry.These solvents contain a large number of VOCs,which not only pollutes the environment,but also has the risk of flammable and explosive.In order to solve the above problems,this paper investigated and analyzed the VOCs emission of industrial cleaning and related key industries,and gives some suggestions on VOCs control in industrial cleaning;at the same time,the special microemulsion cleaning agent for aero engine was developed,the formula and process were optimized,and the related characterization was carried out.The specific research contents are as follows:(1)Based on the investigation,analysis and comparison of VOCs emission in key industries and their source content limits,it is found that the relevant standards of industrial cleaning have some deficiencies such as general classification,incomplete VOCs types and too small scope of application.By collecting the monitoring data of VOCs emissions from various enterprises provided by the Environmental Protection Bureau of a city in Guangdong Province,the emissions characteristics of VOCs in the process of industrial cleaning process.In addition,the VOCs in the industrial cleaning agent were detected by HS-GC-MS technology,and the results showed that there are a variety of VOCs in the cleaning agent of carbon deposition and industrial cleaning agents have become one important source of VOCs emissions in this industry.“Source reduction and replacement” is the most fundamental and effective control technology for VOCs prevention and control in industrial cleaning.(2)In view of the high degree of carbon graphitization and the strong bonding with the matrix,a microemulsion cleaning agent special for aero-engine was developed to realize the source control of industrial cleaning.Through single factor experiment and orthogonal experiment,the best formula for cleaning parts is determined.The optimum dosage of H-1 and H-3 is 12.7 % and 7.3 %,respectively.H-1,Y-1,Y-2 and Y-3 are the key factors affecting the cleaning efficiency of microemulsions and the optimum content is 1.8 %,9 %,3.6 % and 14.5 %,respectively.The cleaning conditions are: soaking for 2 hours,ultrasonic for 30 min,diluting to 20 %,temperature 35 ℃ and dosage of cleaning agent 300 m L.Meanwhile,VOCs composition,surface tension,particle size distribution of the microemulsion cleaning agent were characterized,and the physical and chemical properties and related technical indicators were tested.The developed microemulsion cleaning agent has the characteristics such as low foam,no phosphorus,no fluorine,high flash point,weak alkalinity,safety and environmental protection,and has the function of rust prevention and anticorrosion.It can effectively remove the surface or internal carbon deposition,heavy oil pollution and dust of aero-engine parts,and has achieved good results in practical application.The research and development of carbon micro emulsion cleaning agent and cleaning technology of aeroengine provide an important method and way for the source control of VOCs in industrial cleaning field. |
PDF Full Text Request