Design And Experiment Of Desilter For Shield Slurry Treatment System

With the increasing traffic congestion on the ground, metro as a representative of the underground transport projects has been launched in many cities. Because of its good adaptability to stratum and high efficiency, slurry balance shield technology is widely used. Reasonable disposal of mud is an important part of the slurry balance shield construction process. At present, there are few researches on the treatment of shield slurry in China, and most of them are the summary of the field construction experience and lack of theoretical analysis.In this paper, the design of slurry treatment scheme is carried out on the basis of extensive research on the scheme of shield slurry treatment, the system mainly consists of vibrating screen, desander, desilter, decanter centrifuge, mud pump and other equipment. The system firstly to remove large particles from the mud, and then through the two stage hydrocyclone for small particle removal and particle size control.In order to improve the effect of slurry separation, as the core device of slurry separation system, the numerical simulation method is used to study the influence of the internal flow field and structure on the treatment performance. The single factor optimization method was used to optimize the design of the slurry removing device. After the optimum design, the classification ability of the particles was greatly improved, and the classification efficiency was improved by 12% compared with the optimization. On the basis of the design of the tangential inlet hydrocyclone, the design and numerical simulation of axial inlet hydrocyclone are carried out. The simulation results show that the axial inlet hydrocyclone has a more stable flow field, higher separation efficiency and less pressure drop loss. But the structure of the axial inlet hydrocyclone is more complicated, so in this design used the tangential inlet Hydrocyclone.In order to further study the separation performance of hydrocyclone, the slurry separation experiment was carried out using the design of small treatment volume cyclone. The cyclone has a better separation effect on slurry and the change of inlet flow rate has a great influence on the separation performance of hydrocyclone. In addition, the problem of slurry deterioration caused by the large amount of fine particles in the slurry circulation is also a problem, the experiment of fine particle separation was carried out by using the disc centrifuge, and the experiment proved that the Disc Centrifuge had better clarification to slurry, and the separation efficiency was more than 90%.The research of this paper provides the theoretical and experimental basis for the optimization of slurry separation system, which can provi de reference for the high efficiency separation of slurry for shield.