Research On The Drying Process And Strengthening Method Of Sludge Solar Interlayer

Sludge drying is the critical step for the further disposal of sludge,and the sludge volume and mass could reduce greatly.The conventional drying process of heating process consumes more extra-heating supply,and a special phase of the adhesive phase on the T range of 45-55?will inhibit the further drying,which needs the mixture of the dried sludge back to the system,and reduce the heating efficiency.the explode is another risk for the heating drying.The solar energy drying has been applied for the sludge drying,to reduce the energy cost,while the large land occupied,the long-term drying period,and the odor emissions are three main disadvantages for the solar greenhouse drying.To reduce these problems,a special layer chamber system has been developed and the drying processes were optimized.The special results were shown as below:?1?Screening optimum conditions of interlayer drying:Through the comparison and selection of parameters such as sludge layer thickness,solar radiation intensity,ambient temperature and humidity,it is found that all have an impact on the sludge drying process.When the solar radiation intensity is the same,the thinner the sludge layer is,the faster the drying rate is.When the thickness of the mud layer is 1 cm,the drying effect is the best.When the thickness of the mud layer is the same,the solar radiation intensity is larger and the drying rate is higher fast.Among them,the intensity of solar radiation to a greater extent affects the sludge temperature during drying process.?2?Study on the efficiency and kinetics of solar sandwich drying under the optimal conditions:Mathematical fitting of the dry-curing of solar sandwich was carried out.By comparison of seven dry-curing models,it was found that the Logarithmic model can dry the solar sandwich of the sludge Simulation.R²correlation coefficient is above 0.9.As a result,with the increase of solar radiation intensity,the effective diffusion coefficient of sludge increases with the increase of effective diffusion coefficient of thin layer sludge?5 mm?at solar radiation intensity of 300-700 W/m² to 2.14×10^-117.09×10^-11 m²/s.?3?Study on Solar Sandwich Process:Activated carbon and sodium hydroxide prepared from sludge were used to pretreat municipal sludge.The results showed that with the increase of sludge carbon content,the sludge moisture content decreased slowly When the amount of sludge carbon added is the same,the smaller the sludge carbon particle size is,the faster the sludge drying rate is and the shorter the drying time is.The best addition ratio of sludge carbon is 1%of the dry weight of sludge.The optimal particle size is less than 100 meshes.When a certain amount of sodium hydroxide powder is added,the fluidized sludge can be formed by stirring,and the moisture content decreases obviously.?4?Economical study of solar sandwich drying:Through the system thermal balance and economic calculation analysis,the solar thermal utilization efficiency of this unit is 24.3%.Using this technology to dry the sludge,the treatment cost per ton of sludge is about 122 RMB?including land,construction investment and depreciation?,with obvious cost advantages.