Simulation and analysis for pressure drop of pneumatic conveying of pulverized coal

Pipe pressure drop is one of the most important parameters of pulverized coal pneumatic conveying system.At present, the research on pipeline pressure drop mainly adopts experiment and numerical simulation.The application of process simulation in the study of pneumatic conveying is a research method which not only can quickly simulate the pressure drop characteristics of pipeline, but also meet the engineering application accuracy.This paper uses Aspen Plus, a process simulation software, to conduct the simulation.Firstly, the parameters of the horizontal straight pipe pneumatic conveying model are calibrated through seven groups of experimental data, and the simulations of similar and non-similar conditions with the calibration condition are carried out, and the simulation accuracy of the model is compared and analyzed.Secondly, the influence of pulverized coal conveying capacity and conveying pressure on the pipeline pressure drop is analyzed by using the calibration model.Finally, the coal with inner diameter of 54 mm in Shell coal gasification is analyzed.The pressure drop of pneumatic conveying pipeline is calculated, the pressure distribution diagram of pulverized coal conveying pipeline is drawn, and the proportion of pressure drop of each pipe fitting is compared and analyzed.The minimum pressure drop and economic gas velocity in the conveying phase diagram can be obtained by the simulation.The error between the simulation value and the experimental value of the pressure drop in the horizontal straight pipe is less than 35%.When the simulation conditions are similar to the calibration conditions, the model calculation error is reduced to less than 20%.When the gas velocity is constant, the pressure drop increases gradually with the increase of pulverized coal conveying capacity.When the conveying capacity of pulverized coal is constant, the total pressure drop of horizontal straight pipe gradually decreases with the increase of apparent gas velocity, and the pressure drop curve gradually becomes gentle with the increase of gas velocity, and the influence law of conveying pressure on pressure drop is different under different gas velocity conditions.In the low gas velocity region, the pressure drop of the horizontal straight pipe increases with the increase of the conveying pressure.In the high gas velocity region, the pressure drop of the horizontal straight pipe increases with the increase of the conveying pressure.In the pulverized coal conveying pipeline of Shell gasification, the maximum pressure drop is the vertical section pipeline, up to 51.7%,the horizontal pipe pressure drop is 27.6%,and the bend head 1 and elbow 2 account for 8% and 13% of the total pressure drop.The apparent gas velocity and economic gas velocity increase slowly along the direction of pulverized coal flow, and their average values are 8.8 m/s and 7.1 m/s, respectively.When the velocity difference exceeds 1.5 m/s, the conveying process of pulverized coal can not only maintain sufficient particle concentration, but also avoid the problem of particle settlement blocking the pipeline.