| The flue gas of coal-fired power plants in China contains a large amount of SO2,and China's water and sulfur resources are seriously in short.Therefore,a coal-fired power plant desulfurization technology that can recycle the sulfur in flue gas and consumes less water is urgently needed.The active coke flue gas desulfurization technology has no liquid phase intervention,and can recover sulfur elements in the flue gas through a regeneration process.Therefore,the active coke flue gas desulfurization technology can meet the dual needs of saving water resources and achieving sulfur resource utilization.Coal-based activated coke has a well-developed pore structure and can be prepared in-situ in coal-fired power plants,but its desulfurization performance is low at the exhaust temperature.In addition,the regeneration performance of the desulfurizing agent is critical to the sustainability of the entire cycle desulfurization-regeneration process,and the realization of excellent regeneration performance requires a regeneration process that matches the nature of the desulfurizing agent itself.Aiming at the above problems,this paper uses Jinjie coal as raw material to prepare Fe/AC desulfurizer with high desulfurization activity at flue gas temperature,and studies its regeneration characteristics.This article first designed a five factors and four levels orthogonal experiment with carbonization temperature,carbonization time,activation temperature,activation time,and CO2 flow as experimental factors.The desulfurization amount was used as the experiment index and the best combination for preparing activated coke was obtained through range analysis.The best process combination is:carbonization temperature 700?,carbonization time 60min,activation temperature 800?,activation time 90min,CO2 flow 80mL/min.The iron oxide is supported on the activated coke to prepared the Fe/AC desulfurizer.According to the desulfurization efficiency and sulfur capacity,the iron loading of Fe/AC desulfurization agent was screened,and related characterization was carried out.The experiment shows that the iron load has a significant effect on the desulfurization performance of the desulfurizer.With the increase of the iron load,the desulfurization efficiency and sulfur capacity tend to increase first and then decrease.The desulfurizer has the highest desulfurization efficiency and sulfur capacity when the iron load is 10wt.%.The specific surface area of the desulfurization agent increases first and then decreases with the increase in iron loading.The specific surface area of sulfur capacity is the largest when the iron loading is 10wt.%.The crystallinity of Fe2O3 continues to rise after the iron loading exceeds 10wt.%.The effects of regeneration temperature,N2 flow rate,and regeneration time on the regeneration characteristics of the desulfurizing agent were investigated.The optimal regeneration process of the desulfurizing agent was obtained by taking the desulfurizing agent regeneration rate,mass loss rate,and secondary desulfurization performance as the main indicators.The experimental results show that when the regeneration temperature is in the range of 400?-800?,the regeneration rate and secondary sulfur capacity of the desulfurizing agent increase first and then decrease as the regeneration temperature increases,and the mass loss rate of the desulfurizing agent shows a rising trend.The regeneration rate(85.94%)and secondary sulfur capacity(50.22mg/g)of the desulfurizer were the highest at 500?.The effect of N2 flow rate on the regeneration rate,mass loss rate,and secondary sulfur capacity of the desulfurizer is not obvious.The regeneration rate(88.63%)and secondary sulfur capacity(60.64mg/g)were the highest when the N2 flow rate was 600mL/min.When the regeneration time is in the range of 30min-180min,with the increase of the re-time,the regeneration rate,mass loss rate and secondary sulfur capacity of the desulfurizing agent all show an upward trend.Considering the regeneration cost,the regeneration rate at the regeneration time of 90min(88.17%)and secondary sulfur capacity(59.99mg/g)have reached a higher level,and excessive regeneration will cause energy waste.In summary,the optimal regeneration conditions for the desulfurizing agent are:regeneration temperature 500?,N2 flow rate 600mL/min,and regeneration time 90min.The physical and chemical characteristics of the desulfurization agent before and after regeneration were characterized by BET,FTIR and XRD.It was found that the specific surface area and micropore volume of the desulfurization agent increased significantly after regeneration,and the Fe2(SO4)3 in the desulfurization agent decomposed and converted into Fe2O3.TG-FTIR technology was used to obtain the thermogravimetric curve and gas release curve of the desulfurization agent regeneration process.The possible chemical reactions during the desulfurization agent regeneration process were explored,and the regeneration mechanism was inferred. |
PDF Full Text Request