Study On Process Intensification Of Powder Hopper Discharge Based On Pressure Difference

Based on the application of feeding system in pressurized entrained gasification of pulverized coal,taking the discharge process of powder in hopper as the research object,the process intensification of powder hopper discharge process is realized by applying pressure difference,with emphasis on the change law of constant pressure difference and variable pressure difference.The main contents of this paper are as follows:With the help of the change of pressure signal and weighing mass signal in the discharge process,the influence of constant pressure difference on the material flow rate of different powder materials is analyzed.The experimental results show that the pressure difference can greatly improve the discharge flow rate,and the process intensification effect is obvious under the condition of low pressure difference for the powder materials that can flow freely,while for the adhesive powder materials,the process intensification effect is obvious under the condition of high pressure difference.The process intensification effect of pressure difference on discharge flow rate is explained by rheological theory.for alumina with poor fluidity,the discharge process with constant pressure difference satisfies the pseudoplastic fluid model,and for glass beads and pulverized coal with good fluidity,the discharge process with constant pressure difference satisfies the dilatancy plastic fluid model.Furthermore,through the study of the influence factors of the pressure difference discharge process,it is concluded that the process intensification effect of the pressure difference on the adhesive powder is greater than that on the free flow powder,and the air permeability affects the material flow rate by affecting the pressure in the discharge process.The process of differential pressure discharge is basically not affected by material level height.Finally,according to the dimensional analysis method,the material flow rate model under pressure difference can well predict the discharge flow rate,and the prediction deviation is less than 10%.The variable pressure difference discharge process is studied on the structure of large ventilated hopper in the laboratory,the changing rules of pressure signal and weighing mass signal are obtained,and the effects of pressure difference on average discharge flow rate and instantaneous discharge flow rate are further studied and analyzed.through the theoretical analysis of the stability of the discharge process,a reasonable formula for calculating the operation interval of pressure difference is put forward.