Effect Of Microwave Coupling And Ultrasonic Modification On Pulverized Coal Combusrion Properties

At present, BF coal powder injection in place of partial coke has been widely used in iron and steel enterprises as a proven coal powder injection technique and an effective way to save energy, reduce cost, and improve efficiency. However, the combustion performance of coal is too hard to be improved, which becomes the main defined factor to improve the ratio of coal. In this paper, in order to improve the combustion performance of coal so that it can be combusted completely and reduce the content of unburned pulverized coal and coke rate, the Ultrasound-microwave technology is used to treat the pulverized coal, and then the factors that affect the combustion performance of coal are studied. The following conclusions can be drawn.(1) It can be found that the combustion rate of bituminous lump coal of HongLiulin and the anthracite of Yangquan after the coupling treat get different improvements. The combustion performance of bituminous lump coal treated at132 W power is better than at 264 W. With the increase of microwave power, the rate of volatile matter of coal decreases. The best modification conditions of Yangquan anthracite and HongLiulin coal can be got at 132W×60s and 350W×60s with the combined action of ultrasonic and microwave.(2) Under the external field coupling effect, the starting onset temperature T1 about weight loss of Yangquan anthracite and HongLiulin coal have decreased in some extend, and the devolatilization temperature have declined after treat, which promotes the precipitation of volatile matter. The volatile temperature of the Hong Liulin coal and the Yang Quan anthracite after treatment decrease about 52.8℃ and62.7℃ respectively than the raw coal. When the pulverized coal sample is heated up to 1000 C, the weight loss rate of the treated also increases with the degree of the original sample. The maximum weight loss of bituminous coal increases by 4.89%,the maximum weight loss the Yangquan anthracite by 5.21%.(3) The micro morphology, the bond energy of organic functional groups and the binding mode of the Yang Quan anthracite and Hong Liulin coal have been changed by the synergistic effect of microwave and ultrasonic. After comparing the coupling pulverized coal with raw coal, it can be seen that the crack appears in the surface of the coupling coal. And meanwhile, the lamellar structure can be found in the surface of the Yangquan anthracite coal powder. So it can be concluded that the pulverized coal is graphitized under the action of the coupling field.(4) It is suggested after analyzing the absorption peak intensity on the infrared spectral curve of the pulverized coal treated by coupling field processing, that the radiation has an obvious influence on a variety of organic functional groups, andmajorities of the absorption peak intensity of highly active functional groups have been greatly enhanced, which shows that coupling field can improve the activity of coal volatile and accelerate the speed of chemical bond breakage and restructuring. In the experiments, the number of active functional groups in anthracite and the content of deformation vibration functional group both increase obviously; which leads to the graphite particles of Yang Quan anthracite coal, the improvement of the evaporation rate of pulverized coal and the combustion rate. All of those changes promote the combustion reaction.