Engineering Simulation And Application Of PTFE Hollow Fiber Membrane

Membrane based water treatment process has been widely used due to the small footprint,high efficiency in the field of water treatment.Polytetrafluoroethylene(PTFE)hollow fiber membrane was developed and applied widely due to its good chemical stability and mechanical strength.Polytetrafluoroethylene hollow fiber membrane is prepared by wrapping and heat treatment.It is composed of high temperature resistant support layer and polytetrafluoroethylene filter layer.Wherein the thermal treatment of polytetrafluoroethylene surface,thermal bonding of fibers to form a larger node and has a certain rigidity,so as to obtain a certain filtration effect,and some membrane filaments have no water flux for a long time.Therefore,we need to understand the PTFE hollow fiber thermoforming process and propose new thermoforming methods.In engineering applications,the running water flux of polytetrafluoroethylene hollow fiber membrane is relatively low due to the ineffective membrane area.Therefore,we need to establish a suitable PTFE hollow fiber filter fluid model during operation,to improve the utilization of membrane filaments.Polytetrafluoroethylene hollow fiber membrane is used in membrane bioreactor(MBR),which has the problems of large floor area and high operation cost.We further developed PTFE membrane aeration bioreactor(PTFE-MABR)to improve efficiency of water treatment compared to common membrane bioreactor(MBR)and replace the function of aerobic tank and improve the treatment efficiency.The main content of the work includes the following three aspects.(1)Simulation and optimization of PTFE hollow fiber membrane thermoformingBy designing the simulation model of PTFE hollow fiber thermoforming process,we optimized the heating process,replaced the high temperature support layer.The internal temperature and flow rate of the heating oven blast cycle were analyzed.Comparing copper jacket heating and induction heating,we are able to optimize the replacement of high-temperature support material aramid with ordinary polyester material and reduce the membrane cost by about 40%.(2)Fluid simulation and optimization of PTFE hollow fiber curtain moduleBy designing the fluid model suitable for PTFE hollow fiber filtration operation,we optimized the existing membrane module structure and improved the utilization efficiency of membrane filtration area.A fluid simulation model was established by simplifying the PTFE hollow fiber curtain module according to certain assumptions.Optimization of the membrane modular improves the utilization of the filaments by about 10%.(3)Preparation and application of PTFE membrane aeration bioreactorWe further developed PTFE membrane aeration bioreactor(PTFE-MABR)to improve efficiency of water treatment compared to common membrane bioreactor(MBR)and replace the function of aerobic tank and improve the treatment efficiency.We prepared PTFE membrane aeration bioreactor(PTFE-MABR)using winding,sintering and technique.Polydimethylsiloxane(PDMS)was in situ crosslinked in PTFE fiber,which was then wrapped around with PTFE fibers as a protection layer to obtain a composite MABR membrane.The prepared PTFE membrane was used in MABR,which saved the project area.In this study,three practical problems of polytetrafluoroethylene hollow fiber membrane in the field of water treatment are discussed.Through the simulation of membrane wire hot welding,membrane module fluid simulation,MABR membrane preparation and application,the problems of high cost,low flux and low treatment efficiency of polytetrafluoroethylene hollow fiber membrane are systematically solved.It provides a new idea for further expanding the application of polytetrafluoroethylene hollow fiber membrane in water treatment.