Preparation And Properties Of Modified Iron-Based Desulfurization Agent At Mid-Temperature

Hydrogen sulfide is a typical malodorous gas, it’s a major atmospheric pollutant andit can seriously endanger environment and human health. Mid-temperature coal gasdesulfurization method is regarded as an ideal gas purification technology due to theenvironmentally friendly and simple operation. Developed extensive sources of rawmaterials, efficient, stable performance of desulfurization agent at mid-temperature issignificant for reducing cost and odor pollution. Therefore, in the paper select hydrogensulfide as the target pollutant, the preparation method and sulfidation condition ondesulfurization performance were investigated use the modern analytical methods andresponse surface methodology, and then analyzed the desulfurizer regenerationperformance by modified iron-based desulfurization agent which taking the waste fly-ashas a carrier at mid-temperature in fixed bed adsorption.In this paper, iron-based composite desulfurization agents were prepared by meltingmethod and coprecipitation, by taking the waste fly-ash as a carrier, ferrous sulfate as anactive component precursor, lanthanum nitrate as an adjuvant. It can be found that thedesulfurization agent has very high desulfurization activity with the fly ash added in at aratio of24%of the total mass of the desulfurizer, the molar ratio of La/Fe should be keptabout3%and the heating temperature should be kept at100℃, its saturated sulfurcapacity was29.2%for melting method prepared; prepared by coprecipitation method ofthe optimal prepartion conditions of desulfurization agent was the fly ash added in at aratio of20%of the total mass of the desulfurizer, the molar ratio of La/Fe should be keptabout1%, the time for calcinations is for4h at the temperature of520℃, and thedesulfurization temperature should be kept at400℃, its saturated sulfur capacity was35%.By comparison the performance parameters and the desulfurization effect of thedesulfurization agents which prepared by melting method and coprecipitation, it showsthat the specific surface area and yield of the desulfurization agent prepared bycopercipitation much higher than prepared by melting method, so the desulfurization agentcould effectively improve the desulfurization efficiency.The desulfurization agent was prepared by coprecipitation as the object to explorethe sulfidation conditions on the desulfurization performance in the mid-temperature, theresults show that the desulfurization agent has very high desulfurization activity when the sulidation temperature was400℃, the space velocity was3700h-1.In summary, analyze from characterization techniques and desulfurization efficiency,the best preparation conditions of modified iron-based desulfurization agent prepared bycoprecipitation method, the carrier added amount is20%, La/Fe is1%, the time forcalcinations is for4h at the temperature of520℃, the best sulfidation perfoamance wasthe sulidation temperature was400℃, the space velocity is3700h-1. Under the preparationand sulfidation conditions, the cumulative sulfur content is55.36%after thedesulfurization agent renewable four times. So, modified iron-based desulfurization agenthas good application foreground.