| In this paper,under the microwave frequency of 2.45 GHz,the Xinyu coking coal was selected as the coking coal for research,and the microwave desulfurization experiment was carried out.The optimal desulfurization conditions were determined by orthogonal design: microwave power 750 W,microwave irradiation time 4 min,coal sample The particle size is 80 mesh.In the microwave frequency range of 0.1-6.5 GHz,under different microwave irradiation time,particle size,and oxidizing aid concentration,the dielectric properties of the coking coal were measured by transmission reflection method,and then the different conditions were analyzed for coking coal electrical properties.Under the optimal conditions,3 g of Xinyu coking coal was weighed,and 60 ml of sodium chlorate,formic acid-hydrogen peroxide and acetic acid-hydrogen peroxide were added to the coking coal,and the concentration of the auxiliary agent was 0.01 mol/L.After 0.5 min/L,immersed for 10 min,the microwave desulfurization experiment was carried out,and the coal samples were subjected to the determination of adhesion index,XPS analysis,infrared analysis and scanning electron microscopy.The main results of this study are as follows:1.In the microwave frequency range of 0.1-6.5 GHz,the dielectric constant of the new coking coal decreases with increasing frequency,and as the irradiation time and the number of particles increase,the dielectric constant of the new coking coal is gradually reduced.small.In the microwave frequency range of 0.1-6.5 GHz,the relative dielectric loss factor and medium dissipation factor of the new coking coal show a volatility trend with the increase of microwave frequency.2.At 2.45 GHz,the addition of three oxidizing assistants,sodium hypochlorite,formic acid-hydrogen peroxide and acetic acid-hydrogen peroxide,has a beneficial effect on the desulfurization of coking coal.When the immersion time was 60 min,the desulfurization rate was 11.19 % and the adhesion index G was 63.67.The addition of formic acid-hydrogen peroxide auxiliary was 20 min.When the concentration of the additive is 0.1 mol/L,the desulfurization rate is up to 11.07 %,and the bond index G is 66.87.When the immersion time is 60 min,the additive concentration is 0.5 mol/L.The maximum desulfurization rate was 11.97 %,and the bond index G was 58.35.3.According to the analysis of the basic properties of coking coal,the coal-like bond index after treatment has a different degree of decline than the original coal bond index of 73.18.Through XPS analysis and infrared analysis,it is known that the sulfur content of coal is mainly removed by thiophene type sulfur,9.78 % when sodium hypochlorite additive is added,and 10.87 % when adding formic acid-hydrogen peroxide additive.The hydrogen peroxide auxiliary was removed by 24.49 %.This paper has 36 pictures,19 tables,and 87 references. |
