Study On Liquid-Solid Separation Dynamics Of Fine Coal Powder Particles Under Bidirectional Enhanced Force

In recent years,with the central government attaching great importance to environmental protection,and the people's awareness of environmental protection has increased significantly,the production process of resources and environmental issues must be taken into account at the same time.Coal separation and processing is the source of clean utilization of coal,and coal washing is an important link in coal separation and processing,so the treatment of slime water has become an unavoidable problem,which is directly related to the quality and quantity of products in coal preparation plant.Excessive moisture content of coal will bring a lot of inconvenience and waste in the process of storage,transportation and use,this is especially true in the winter in the alpine regions.At present,the commonly used dehydration methods in coal preparation plants are gravity dehydration,centrifugal dehydration,filtration dehydration,pressure filtration dehydration,drying dehydration,etc.This paper aims at the shortage of fine particle dehydration in the dehydration process of coal preparation plant.According to the principle of centrifugal sedimentation and filtration separation.By using modern computational fluid dynamics(CFD)technology,the force of particles in the screen basket and the flow field characteristics in the screen basket were studied through numerical simulation analysis and experimental verification,and the structure of the existing vibration filter centrifuge was improved.Through theoretical research,the dynamic characteristics of particle in sieve basket,such as force,velocity and acceleration,are analyzed.The influence of half-cone Angle of sieve basket on separation is analyzed by means of multi-body dynamics software ADAMS.The dynamic characteristics of the particles in the sieve basket were further quantified,analysis to determine when the half cone Angle is 17°,pulverized coal particles stay in the sieve basket for the longest time,and speed and acceleration value is bigger,the most good solid-liquid separation.Through Solidworks software 17° half taper Angle of screen basket model is set up,The rotary vibration motion of the sieve basket is realized by using UDF in Fluent software.The flow field characteristics in the sieve basket are further analyzed and demonstrated.Single variable method was adopted for analysis,influence of that rotational speed,excitation force,coal powder particle concentration,particle size and inlet velocity of the pulverized coal particle on the flow field characteristics of the sieve basket were discussed respectively.The results show that the separating effect of solid-liquid two-phase of pulverized coal particles increases with the increase of rotating speed.When rotating speed is 1500 rpm,the separating effect of solid-liquid two-phase in sieve basket is better.For ultrafine pulverized coal particles,there is almost no separation effect when the rotational speed is lower than 800rpm;In terms of the properties of pulverized coal,the larger the particle size is,the faster the settling speed is,and the better the separation effect is.This is mainly due to large particles,larger pores,less capillary water,water is relatively easy to remove;the concentration of pulverized coal particles has a great influence on the viscosity of materials.When the percentage of pulverized coal particles increases,the viscosity of pulverized coal particles increases greatly,so that the internal moisture can be maintained,water is difficult to remove,the lower the concentration of pulverized coal is,the smaller the viscosity is,and the more favorable to water removal;The flow field in the sieve basket is sensitive to the inlet velocity,when the velocity is greater than 5m/s,the particles cannot fully participate in the rotary vibration movement of the sieve basket and are washed out of the sieve basket,so the separation effect is poor,the slower the inlet velocity is,the more sufficient the separation is.When the inlet velocity is 0.01m/s,the separation effect is the best.Applying axial high frequency excitation force can significantly increase tangential velocity and axial velocity,which is more conducive to the separation of liquid and solid phases and the discharge of pulverized coal residue after dehydration.So for ultrafine coal particles,according to the size of the separation equipment,By selecting high speed,low feed speed,low feed concentration,axial vibration force to enhance the solid-liquid separation effect.