Research On Prevention Sticking And Save Energy System With Two-stage Drying Of Sewage Sludge

With sewage sludge problem increasingly,from safe disposal perspective of sludge,this paper analyzes the current sludge treatment technology,and expounds the harm of sludge.The key of sludge treatment is how to reduce the sludge moisture content.Sludge drying process is one of the most effective way.Through the analysis of the existing drying technology and equipment at present,solving the sludge wall sticking and energy saving drying method are reviewed in this paper.The research about high energy consumption,drying rate slow,sludge wall sticking and tail gas can not be solved in sludge drying is study by me,main research contents as follows:Hot air and microwave drying test is carried out on the sludge.Designing a kind of sludge sealed annular heating drying machine to solve sludge wall sticking problem and a a kind of two-stage energy-saving drying system to dry sludge quickly and achieve the goal of energy conservation and environmental protection.After hot air and microwave drying experiments,I find that sludge drying rate is associated with sludge thickness.In the dry late period,sludge drying rate decreased gradually as the moisture content reduced.Microwave power is higher when drying time is shorter.After hot air drying,the more crack occurred on the surface of sludge.After microwave drying,the less crack occurred on the surface of sludge.Under the same microwave power,sludge thickness is more thick.In contrast,its energy consumption per unit mass is lower.After hot air drying,crack occurred on sludge can speed up the microwave drying rate,and the sludge volume will large shrink after drying.In view of sludge sticking phenomenon,Study on the shrinkage characteristics of sludge,a kind of sludge annular heating drying machine is designed by using the principle of sludge drying and shrinking and drum drying technology.Drying machine includes an annular grooved drum,a sealed box body,a transmission system,a steam passage and a corresponding attachment.The equipment completely put drying device sealed in the box,and sludge is sealed in the annular groove for rapid heating and heat conduction and convection drying at the same time.The sludge volume will rapidly shrink and crusted after drying.The sludge leave the heat transfer surface to achieve the effect of dry and not wall sticking.The device mechanical energy consumption is small and the sludge drying time is short and the heat loss is low.In order to solve the high energy consumption problem of sludge drying,a kind of sludge two-stage energy-saving drying system is designed.First-level drying uses superheated steam,which has large heat capacity,strong hygroscopicity,and energysaving characteristics as a heat source for drying.Flash steam and steam compression techniques are used to recycle the energy and steam consumed for drying.Secondarylevel drying uses hot air and microwaves to dry at the same time,and the heat pump technology is used to recycle the latent heat of steam and reduce the moisture content of hot air and accelerate drying rate,so that the sludge is quickly dried and the energysaving effect is achieved.