Experimental Study On Optimized And Matching Of Fluidized Conveying Parameters In The Blast Furnace Pulverized Coal Injection

Modern blast furnace coal injection technology has become one of the most effective methods to save coke and improve the iron process.It not only can partially replace increasingly scarce coke,and is beneficial to improve ironmaking process.Therefore,the technology of blast furnace jet coal has become the primary measure for reducing the cost of iron,reducing the environmental pollution and improving the technological structure of the furnaces in the world.At the same time,increasing the quantity of blast furnace powder and the stability of blowing and blowing are also the common goal of most smelting enterprises.However,bigger powder spraying quantity is not better,each of the blast furnace has an associated with itself smelting condition and corresponding optimal amount of powder injection.In ensuring maximum under the condition of comprehensive economic benefits,achieve the best powder quantity and stability of blast furnace is one of the focus of current research of blast furnace ironmaking workers.In this paper,aiming at the main parameters and process equipment that affect the amount of the solid mass flowrate,solid-gas ratio and stability of blast furnace coal injection,a pneumatic conveying experimental platform of fluidized blowing powder was established.The influence of the pressure,the top pressurizing gas and bottom fluidizing gas ratio,and the ratio of secondary supplemental gas to the amount of solid mass flowrate,solid-gas ratio and stability were investigated through the experimental system.The main work and results are as follows:Firstly,the fluidized performance parameters of pulverized coal for experiment were measured by using the powder tester developed independently by the project team.Particle size and composition of pulverized coal were analyzed by laser particle size analyzer,and for the convenience of observation,a pulverized coal substitute powder(PVC)with the same fluidization ability with pulverized coal was found.The gas distribution board is subjected to the resistance characteristic experiment,the airflow uniformity experiment and the powder Particle tracing experiments,screening out the gas distribution plate to meet the requirements of transport experiments.The effect of the ratio of the top pressurizing gas and bottom fluidizing gas on the amount of solid mass flowrate,solid-gas ratio and stability was investigated.The results show that under the premise of stable tank pressure and other conditions,with the increase of the ratio of the top pressurizing gas and bottom fluidizing gas,the solid mass flowrate and solid-gas ratio firstly increase and then decrease,reaches the maximum at a certain percentage,whereas the best stability.The effect of pressure on the amount of solid mass flowrate,solid-gas ratio and stability was studied.The results show that with the increase of pressure,the amount of solid mass flowrate continues to increase,while the solid-gas ratio increases sharply at first and then increases little,and the stability does not change obviously under each pressure.The effects of the ratio of secondary supplemental gas on the amount of solid mass flowrate,solid-gas ratio and stability were studied.The results show that with the increase of the secondary gas ratio,the solid mass flowrate and the solid-gas ratio first increase and then decrease,and reach the maximum a certain percentage,but the stability does not change obviously,all can achieve stable delivery.Using the software COMSOL5.3a to simulate fluidized bed gas-solid two phases flow.2D single-phase flow and 3D two phases flow numerical simulation were carried out.The results show that: From the flow behavior of macroeconomic,powder nearby distribution board to discharging mouth were fluidized first.And forms a circular flow of gas in area B,the powder of the C area constantly to collapse area B,until the end of the convey.