Analysis Of Seal System For Supercritical Carbon Dioxide Continuous Extraction And Design Of Key Equipment

Supercritical fluid extraction?SFE?technology is a new green extraction and separation technology with high extraction efficiency,good product quality,environmental protection and pollution.However,there is an important problem in the current supercritical fluid extraction technology,that is,the extraction equipment is intermittent equipment,which requires multiple loading and unloading operations during the extraction process,which results in huge energy loss and potential safety hazards.In this paper,the author proposes a continuous supercritical fluid extraction process and equipment,which promotes the development of supercritical fluid extraction technology to the direction of high efficiency,energy saving,environmental protection and safety.Through the analysis and comparison of supercritical CO₂ extraction processes at home and abroad,based on a supercritical fluid continuous extraction separation unit system,the process flow of supercritical CO₂ extraction system is introduced,the idea of fractional continuous extraction is realized,and the structure and form of the main equipment in the system are selected.Aiming at the key high-pressure sealing problem in the continuous supercritical fluid extraction equipment,the axial thrust installation model of the O-ring was established,and the influence of various factors on the mechanical properties of the O-ring during installation was studied by changing the compression ratio,friction coefficient and introduction Angle by using the finite element analysis software.The results show that as the compression ratio increases,the friction coefficient increases,the lead angle?increases,and the inner corner fillet R₁ decreases,O-ring all the stress value increases,and change into outer side Angle of the rounded R₂ and introducing the length of Z,O-ring Von Mises stress peak value is constant,considering the influence of various factors,choose the compression rate is 10%-14%,the friction coefficient is 0.1-0.15,introducing Angle is 15°and inner end corner R₁ is 5mm,O-ring,respectively with the best performance,the selection of the outer corner R₂ and the introduction length Z is convenient for processing.In order to study the sealing performance of the O-ring in the working state,the finite element analysis model of the O-ring in the working state was established,and the O-ring with the medium pressure of 0-8MPa,8-16MPa,16-24MPa and 24-32MPa on both sides and the O-ring made of polyurethane,nitrile rubber and fluorine rubber were simulated.The results showed that the contact pressure of polyurethane O-ring was always greater than the maximum internal pressure with the increase of the medium pressure on both sides of the O-ring.After changing the O-ring material,it was found that the three materials of polyurethane,nitrile rubber and fluorine rubber could all meet the sealing requirements,and the contact pressure of polyurethane was the highest.However,when the medium pressure was high,the fluorine rubber O-ring appeared permanent deformation.Considering comprehensively,the O-ring was the most suitable choice of polyurethane material.According to the technological process of supercritical CO2 continuous extraction and separation system,based on the simulation analysis of the Installation process and working status of O-ring,the design of key equipment in the system was completed,the structural dimensions of continuous extractor,separator and CO2 storage tank and their components were determined,and the strength calculation and check were carried out.