The Preparation Of ZnFe₂O₄ High Temperature Coal Gas Desulfurizer By Coprecipitation Under Ultrasonic

Energy problem is a core issue of this society.The energy reserves, structure,less conversion methods,operating mechanism and the technology of exploitation are facing challenge to China's economy.Clean coal technology is a new technology,which make coal as an energy to achieve the greatest potential and be used by the release of contamination at the lowest level,and use coal efficiently and cleanly.More than 70%of China's energy depended on coal,so it's very important to development the clean coal technology.Gas Purification is one of the important parts of clean coal technology,and high temperature gas desulfurization is the core of gas purification.So the research and development of high-temperature gas desulfurizer are very important,and have been widely concerned.The research and development of high temperature coal gas desulfurizer have changed gradually from mono-metal oxide into mixed-metal oxide,in which zinc ferrite sorbent has become the typical mixed-oxide desulfurizer, because of its high desulfurization precisior,high sulfur capacity and high reactivity.This thesis adopted coprccipitation under ultrasonic to get zinc ferrite precursors,then adopted calcination to gain active components of zinc ferrite, and the zinc ferrite prepared have the spinel structrure.Then treated zinc ferrite as active components,and used kaolin as structural additive to get high temperature gas desulfurizer.The thesis also characterized zinc ferrite desulfurizer by means of XRD,SEM etc.The results showed that the temperature and time of calcination had more effects on crystal size and property of desulfurizer.The thesis explored desulfurization and regeneration under the fixed-bed reactor and simulated coal gas atmosphere.The conclusions are as follows:1.It is feasible to adopt coprecipitation under ultrasonic to get zinc ferrite, and the ZnFe₂O₄ as high tempetature coal gas desulfurizer was prepared,which is excellent high temperature desulfurizer.2.The content of zinc ferrite in the sorbent is around 35%in order to achieve high sulfur capacity and high transform ratio.The reactivity could be improved by addition of little starch to the zinc ferrite sorbents.3.In the process of coprecipitation under the ultrasonic radiation, component uniformed was gained,small particled zinc ferrite precursors formed spinel structrure.Zinc ferrite crystal grain gained was well distributed,whose range was from 40-80nm,and the crystal grain appeared global.4.Compared the zinc ferrite gained under ultrasonic with the zinc ferrite gained by normal method,the cry,stal phase of the former is more complete,and the crystal grain is well distributed.The results showed that the ultrasonic promoted the formation of its configuration.5.The zinc ferrite gained by ultrasonic showed good and stable properties in the process of desulfurization experiment.When the concentration of inlet H₂S is 3023ppm,that of outlet keeps about 30ppm.6.The results showed the desulfurization efficiency of the excellent desulfurizer is 99%in the fixed reactor experiment.