Study On Preparation Of Modified Activated Carbon Adsorbents And Their Desulfuration Performance For Natural Gas

In this paper,HNO₃/AC、NaOH/AC and Fe₂O₃/AC adsorbents were prepared by HNO₃/AC and NaOH impregnation method and Fe₂O₃loading method.The absorbents were characterized by N₂-BET and SEM methods.The preparation conditions of the HNO₃、NaOH and Fe₂O₃ modified activated carbon adsorbent and the effect of the adsorption process conditions on the removal of hydrogen sulfide from natural gas were investigated in a fixed adsorption bed absorber.The experimental results show that:（1）The optimum conditions for oxidative impregnation liquid modification are:HNO₃ as impregnation liquid,HNO₃ concentration 12%,impregnation time 24 h.At adsorption reaction temperature of70°C,the desulfurization rate of the HNO₃/AC adsorbent was as high as 99.0%,the saturated sulfur capacity was 36.7 mg/g.（2）The optimal conditions for alkaline impregnation liquid modification are:NaOH as impregnation liquid,NaOH concentration8%,impregnation time 24 h,calcination temperature 350°C,and calcination time 2.5 h.The desulfurization rate of the NaOH/AC adsorbent was as high as 99.2%,the saturated sulfur capacitywas 46.6 mg/g.（3）The optimum conditions for Fe₂O₃ loading modification are:the mass ratio of Fe₂O₃ to activated carbon of 1:1,the vacuum drying temperature of80°C,the drying time of 36 h.At adsorption reaction temperature of 60°C,the desulfurization rate was as high as 99.4%,the sulfur capacity was 77.9 mg/g.