Study On The Resistance Characteristics Of Composting Materials Under The Action Of Drum Type Turner

With the development of social economy,environmental issues have become increasingly prominent.The sludge carries more than half of the pollutants in the sewage.If it is not effectively treated,it will cause secondary pollution to the environment.With its mature and stable characteristics,composting technology has developed into one of the mainstream sludge treatment technologies widely used.At present,the large and mediumsized sludge treatment projects in China mainly adopt the dynamic trough composting process with the turner as the core equipment,but the current design of the turner adopts the traditional design such as semi-theoretical/semi-empirical design method,analogy method and intuition method.The method has the problems that the theoretical basis is not sufficient,the customized design cannot be realized,and the dynamic parameter model is single.It is easy to cause the power of the dumping machine to cause “stopping” phenomenon or excessive power and waste of resources.Based on the working condition of the drum type turner in the SACT composting process,this study carried out in-depth research on the resistance characteristics of composting materials.It aims to supplement the design theory of the turning machine by developing the mechanical properties of composting materials,optimize the operating parameters of the SACT process,and improve the system adaptation.The main research results obtained in this study include: 1)proposing the resistance characteristic index of compost material,establishing the mathematical model ?=f(material parameter system)of shear strength and material parameters,and selecting 7 parameters to form the material parameter system,and determined A test plan was prepared for five parameters of stack height,temperature,water content,density,and particle size distribution.2)For the first time,the material characteristics of the SACT process were studied.The site shear test of the shear strength and material parameters of the pile was carried out at the Luoyang Sludge Treatment Plant,and 420 effective data were obtained.3)A method for detecting shear strength is proposed.The non-standard test equipment VST140 and 150 cross-plate shearing instrument are designed.The measured limit torque data is 8.15% from the theoretical value.The equipment is used for in-situ measurement of shear strength.reliability.4)Through the EDEM discrete element software,the VST150 shear test simulation of the discharge end is carried out,and the correlation between the material parameters and the simulation model parameters is established,and the model parameters are corrected.The simulated limit torque value and the measured value error are 9.3325%.5)The BP neural network algorithm is used to establish the shear strength prediction model,that is,the input pile height,temperature,water content and density are predicted to predict the shear strength value.The average error between the predicted result and the measured value is 11.35%.6)In this study,the distribution of shear strength of SACT process piles was obtained: the maximum value appeared at 14~20m from the feed end of the fermentation tank,and the second largest value appeared at the highest point of the pile at the discharge end,with an average ratio of about 1.3.In this study,the mechanical properties of compost materials were studied from theoretical,experimental,measured,numerical simulation and BP neural network.The cross-plate shearing instrument is suitable for the existing composting site.By measuring the ultimate torque of the discharge end and combining its distribution law,the maximum shear strength and position of the whole warehouse are predicted.The EDEM simulation model is suitable for the single material state.The parameters are derived from the shear strength;the BP neural network prediction model is suitable for establishing a database,and the variation law of various material parameters is derived from the shear strength in reverse,and the scheme for the design of the turner and the optimization of the process parameters are provided.This research has practical significance for the improvement of the design theory of the turner and the intelligent design of the composting project.