The Study Of Dense-phase CO₂ Cleaning Technology For Typical Dirt Of Remanufacturing Cores

Remanufacturing,as an important carrier for promoting the concept of green development and low-carbon development and promoting the construction of ecological civilization,is an important direction for the transformation and updating of manufacturing industries.It can not only achieve product life-cycle recycling,but also can greatly reduce the remanufacturing production process.The use of raw materials and energy consumption in China are in line with the requirements of the national circular economy development.For the remanufacturing of used engine parts,remanufacturing cleaning is an important part of the quality of remanufactured engine parts.Its role is to remove residual dirt on the parts of used products,facilitating subsequent analysis,parts inspection and maintenance.Remanufacturing cleaning is an important part of the remanufacturing system and is closely linked to the quality of remanufactured products.At present,remanufacturing and cleaning technologies are changing with each passing day,and there are many kinds of them,but all of them have their own advantages and disadvantages,and it is urgent to find a cleaning technology that meets the needs of green sustainable remanufacturing.This paper proposes the use of dense-phase CO₂ fluid cleaning technology for decontamination,and analyzes the mass transfer problems in the dense-phase CO₂ cleaning process for typical fouling of remanufactured cores.Convective mass transfer coefficients are the main parameters for estimating mass and mass transfer rates,but the coefficient is related to many factors such as the geometry of the inner wall of the cleaning tank,the nature of the CO₂,and the flow rate,and it is difficult to accurately estimate the amount.This is also one of the main reasons why the industrialization of dense-phase CO₂ cleaning technology is relatively backward.Therefore,the in-depth study of the various transfer properties of dense-phase CO₂ is the key to solve the mass transfer problem in the dense-phase CO₂cleaning process.This paper takes the used engine as the research object,and mainly studies the cleaning of the lubricating oil in the worn-out engine dirt by the dense-phase CO₂ fluid.Using the experimental design method,through the six-factor two-level orthogonal test of design temperature,pressure,cleaning time,flow rate,auxiliary solvent and baffle size,the influence of various factors on the cleaning efficiency of dense-phase CO₂ was explored,and the best cleaning process was obtained.The conditions and the highest cleaning efficiency achieved under this condition,and the establishment of a mathematical model for the efficiency of lubricating oil cleaning.The composition of different viscosity lubricating oils was explored using the gas chromatographic analysis technology,which laid a theoretical foundation for the analysis of cleaning efficiency of dense-phase CO₂ cleaning different viscosity lubricating oils.In order to further improve the cleaning efficiency,the original cleaning equipment cleaning vessel structure has been improved.Based on ANSYS Fluent software,the internal flow field of the main equipment cleaning test was simulated to obtain the fluid velocity distribution under different structures.The internal structure of the cleaning vessel was designed and optimized,and the results were verified by comparative experiments.After the internal structure of the cleaning vessel is improved,the fluid velocity on the surface of the cleaning object is increased,the dissolved solute of the dense-phase CO₂ fluid per unit time is increased,and the erosion effect of the dense-phase fluid on the dirt is enhanced,thereby increasing the removal rate of dense-phase CO₂ for the automobile lubricants.The removal rate of engine lubricating oil verified the effectiveness of the structural improvement of the cleaning equipment cleaning vessel.