Simulation Of Microwave Pretreatment Sludge Reactor Based On HFSS-Fluent

With the continuous increase of water consumption,the efficiency of municipal sewage treatment has increased,resulting in an increase in sludge production year after year.The excess sludge contains high levels of heavy metals and many organic materials that are difficult to degrade,which is not conducive to anaerobic digestion of the remaining sludge.Pretreatment of the sludge can increase the anaerobic digestion efficiency of the sludge.The microwave irradiation method is an effective pretreatment method.As the previous research results of the research group showed that the modified activated carbon fiber combined with microwave treatment can effectively improve the anaerobic digestion effect of the later stage of the sludge,based on this theoretical basis,the microwave pretreatment sludge reactor simulation study.The basic design of the sludge microwave pretreatment reactor was carried out in this paper.The shape of the reactor installed in the sludge pretreatment,the position and number of microwave generators,the size,and the sludge treatment volume were determined.Electromagnetic fluids were established through HFSS and FLUENT.The thermal coupling simulation model was used to simulate reactor cavities of different structures and sizes,and comparative analysis was conducted to select the most suitable microwave sludge tube reactor.For a cylindrical cavity reactor,the intensity of microwave radiation in the cavity of 50 mm,60mm,70 mm,90mm,100 mm,120mm,130 mm,160mm,180 mm,190mm,and 200 mm radius is attenuated along the wall of the reactor tube,and the radiant energy is mainly concentrated in the Within 30 mm to 60 mm from the surface of the pipe wall;radius is 80 mm,110mm,140 mm,150mm,170 mm.Microwave radiation intensity in the cavity is attenuated along the wall from the center to the reactor.The radiant energy is mainly concentrated in the center of the tubular reactor.The radius is In the area of 90 mm,for the coaxial reactor,the inner diameter is 180 mm,160mm,150 mm,100mm,and 80 mm.The distribution of radiation intensity in the cavity is uniform,and the radiation energy is mainly concentrated in the area of 20 mm to 60 mm from the surface of the outer tube wall,and the radius is 40 mm.In a coaxial cavity of 20 mm,the intensity of microwave radiation is attenuated inward along the outer wall of the radiation intensity.The radiant energy is mainly concentrated on the outer tube wall,and the radiant intensity in a cylindrical cavity with a radius of 60 mm is attenuated outward in the tube wall,and the radiant energy is mainly concentrated.In the tube wall of the tubular reactor,the radiant energy of coaxial cavities in other radii is dispersed,and the radiation intensity has no obvious regularity.When the sludge fluid in the cylindrical cavity approaches the central area of the reactor,the sludge flow velocity is the largest.The smaller the distance between the sludge and the outer wall of the cylindrical cavity of the reactor,the smaller the velocity of the sludge fluid,and the sludge flow rate is constant.The wall sludge has a longer microwave radiation time.In the coaxial reactor,the flow velocity of the sludge fluid between the inner and outer tube walls is the largest.As the distance between the sludge and the inner and outer walls of the coaxial chamber decreases,the velocity of the sludge fluid in the reactor gradually decreases and approaches.Sludge on the inner and outer walls of the coaxial cavity has a longer microwave radiation time.Both a 170 mm diameter cylindrical chamber reactor and a coaxial chamber reactor with an inner diameter of 100 mm can cause a temperature rise of more than 8K,and the high value area is the largest in the same type of reactor,and the sludge in the reactor exceeds 70% of the area.Can receive enough microwaves,and can cause temperature rise above 5K,and the ratio of microwave radiation blindness between the two is close.From the perspective of the microwave blind zone,the overall acceptance of microwave radiation in the coaxial cavity is superior to the cylindrical cavity.Through the above analysis,the coaxial cavity with an inner diameter of 100 mm was chosen as the optimal reactor.