Research On The Key Recycling Technologies Of End Of Life Passenger Vehicle Plastics Reuse With Equivalent Performance

With the rapid growth of passenger vehicle population in China, the number of scrapped vehicles in 2020 will reach 8 million and the amount of retired plastics reaching almost 1 million tons. Currently, China’s recycling industry for passenger vehicle plastics is still in its infancy stage; inappropriate industry management and backward recovery technologies result in serious pollution and under-maximization of recycled passenger vehicle plastics. Therefore, the creation of a suitable model for China’s automotive recycling industry as well as key recycling technologies are necessary to promote the rapid, healthy development of the recycling industry and the sustainable development of the Chinese automobile industry.Therefore, this study regarded retired passenger vehicle plastic as its research object. The key technologies utilized in recycling passenger vehicle plastics reuse with equivalent performance were investigated. The research content and conclusion are as follows:1. Investigation of the recycling mode of retired passenger vehicle plasticsThe advantages, disadvantages, opportunities, and challenges of the Chinese passenger vehicle plastic recycling industry were systematically analyzed through SWOT analysis method. The total weighted scores of the external factor evaluation matrix(EFE matrix) and the internal factor evaluation matrix(IFE matrix) were obtained respectively. The passenger vehicle plastic recycling model-plastic recycling model based on extended producer responsibility was formulated according to the analysis of the two-level SWOT matrix. Recovery schemes for the typical plastic parts of passenger cars were developed based on previous studies on the relevant characteristics of passenger car plastic products.2. Theoretical model of the friction charging mechanism of passenger vehicle plastic particles and its movement properties in high-voltage electric fieldsA mathematical model for plastic particle collision charge in the friction barrel-type charging device was developed based on the results of the analysis. The plastic particle force model in the electrostatic separation chamber was deduced; and the particle movement differential equations were also derived. The numerical simulation of the electric field intensity distribution of the designed electrostatic separator during passenger vehicle plastic separation was performed with the mathematical simulation software MATLAB. The electric field intensity distributions under different voltage and electrode characteristics were analyzed. The electrostatic separation experiments of PP and ABS mixed plastics were studied based on factorial design experimental method. The mathematical interaction models of separation for the two types of plastic were also established. The optimization of the high-voltage electrostatic separation parameters PP and ABS was achieved.3. Research on the mechanism of plastic coating removal by water jetAn energy-based model of passenger car plastic polymer coating removal by a water jet was established based on the analysis of the relationship between surface coating removal rate and water jet power density. The model was underpinned by water jet net power NETE and power density at different jet radii dAE. The formulas for the energy density d A,CLE and cutting depth CLz of the water jet cutting seam center line on the surface of the processed materials were also developed. By the numerical simulation with the fluid simulation software FLUENT, the feasibility plastic surface coating removal by 35 MPa water was verified. Related experiments were performed according to the developed water jet coating removal equipment and orthogonal experimental method. The mathematical model for the coating removal rate of the bumper and the optimal scheme of coating removal were also established based on the experimental results.4. Research on recycled passenger vehicle plastic particles utilized in new vehicle plastic componentsThe process flows of the granulation production line for typical scrapped passenger vehicle plastic materials and the reproduction of corresponding auto parts with recycled plastic particles were developed. With bumpers, dashboards and door panels as examples, the application of recycled plastics in new passenger vehicle components were discussed comprehensively. The results show the feasibility of using recycled plastics in the production of new parts and provide a sound foundation for high value-added reutilization of scrapped passenger vehicle plastics.In summary, the scrapped passenger vehicle plastics recycling model and its reuse with equivalent performance technical schemes were researched in this dissertation. The retired passenger vehicle plastic recycling key technologies, such as high-voltage electrostatic separation, coating removal by using water jet, the aging performance tests and the applications of recycled plastics in new passenger vehicle components, were comprehensively researched. This provides theoretical guidance and technical support for the development of scrapped passenger vehicle plastics.