Research And Optimization Of Sulfur Powder Closed Nitrogen Protected Impact Mill System

In modern industrial production,powdered sulfur plays an important role as a basic material.However,due to its extremely poor conductivity,sulfur has a high explosion risk during crushing.In order to solve the explosive problem of sulfur,this paper proposes an inert gas-protected impact mill pulverization method for the preparation of sulfur,and combined with industrial test,numerical simulation and laboratory experiment three ways to study the entire system,for the future The large-scale preparation of sulfur powder provides a basis.Through the type selection design of the sulfur powder closed nitrogen protection graded impact mill system equipment,then the industrial system was built and the operation debugging and industrial test were carried out,and the system operation problems were theoretically analyzed.Numerical simulation was used to study the internal flow field law of the closed system;in order to solve the problem of large dust concentration at the outlet of the dust collector,a secondary purification laboratory platform was built.The secondary purification improves the feasibility of the working performance of the surface cooler.The preliminary preparation of the entire system includes the preheating of the oxygen content analyzer and the reduction of the oxygen content of the system.This process takes about 45 minutes;during the normal operation of the equipment,the pressure difference of the dust collector is 1.4 k Pa,the outlet pressure is about-1.0 k Pa,and the host pressure The difference is stable at about 1.45 k Pa;the oxygen content and pressure of the system are controlled by two supplementary gas valves and two exhaust valves.The oxygen content of the system is about 2% during stable operation;the test results obtained by adjusting the speed of the classification wheel show that: The speed of the classifier is 450 r/min,which can meet the technical requirements.Under this operating parameter,the system can obtain the finished sulfur powder with d90 of 72.17 μm,the output is 1175 kg/h,and the power consumption is 43.079 k W·h/t.It can be known from the test that the closed system can safely and stably prepare sulfur powder for 200 mesh rubber.In industrial production,the higher pressure in the negative pressure part of the system will cause more nitrogen consumption to maintain the oxygen content.By increasing the uniformity of the pressure distribution of the system,this problem can be effectively solved.Based on the operating parameters of industrial experiments,with the help of CFD numerical simulation,the pressure distribution law of the system is explored.The results show that when the inlet pressure of the system is 7.5 k Pa and the outlet pressure is-1.44 k Pa,the system flow rate is 5153 m3/h,the filter bag’s filtering air speed is 1.14 m/min,the pressure difference of the dust collector is 1.4 kPa,and the outlet pressure of the dust collector is-0.264 k Pa,which is the optimal pressure distribution.At this time,the pressure at the negative pressure part is small,which saves nitrogen consumption and can ensure the stable operation of the system.In addition,during industrial production,there is sulfur dust attached to the surface cooler in the system,which will reduce the working efficiency of the surface cooler.This problem can be solved by adding a filter cartridge to the original dust collector for secondary filtration.According to the air volume of the system,a single filter cartridge with a filter area of 23.5m3 is selected,and three additional cartridges are installed.Experiments are conducted to find out the change rule of the filter cartridge resistance and filtration efficiency with the filter wind speed.The results show that: when the filtering air velocity of the filter cartridge is 1.3 m / min,the operating resistance of the system is 0.4 k Pa;at the same time,when the inlet gas-solid concentration is 100 g/m3,the operating resistance needs 35 minutes to reach1 k Pa.According to the general bag type dust removal The filtration efficiency of the filter is more than 99.9%,and the dust concentration at the outlet of the filter bag is calculated to be16±2 mg / m3.It is estimated that when the inlet gas-solid concentration is 16 mg/m3,it will take 6 days to reach the resistance of 1 k Pa,and work according to 8 hours per day System,it takes 18 days to clean the filter cartridge once.