Study On Preparation And Regeneration Technology Of Activated Carbon Desulfurizers

Hydrogen sulfide （H₂S） is a toxic and harmful gas, with the smell ofrotten eggs, primarily exist in natural gas, coke oven gas and petroleumcracking gas. Under atmospheric pressure, H₂S gas is acidic and cancause equipment corrosion and cause catalyst poisoning, the burning ofH₂S will release SO₂,which will also cause air pollution. Therefore, theconcentration of H₂S must be strictly limited, the natural gas must gothrough desulfurization process before it is used, for example, accordingto the rules, the concentration of H₂S in the natural gas must be less than5mg/m³.Activated carbon （AC） is a kind of artificial porous material,because of its high specific surface area, rich in raw materials and lowcost etc., AC has been widely used in sewage and waste gas treatment. Inthe process of dealing with waste gas, AC is often used in adsorption ofH₂S, but because its adsorption effect is poor, people often need loadsome kinds of the catalysts to improve its adsorption catalytic activity,Common load catalysts have KOH, NaOH, Na₂CO₃, metal salt and so on.The alkaline substance loaded on AC can have reaction withH₂S,which would significantly improve the chemical adsorption of AC.And metal salt may change activated carbon internal pore structure andchemical properties, it also have good catalytic oxidation function, so asto speed up the desulfurization reaction rate and improve thedesulfurization performance.For the objective of understanding the effect of AC desulfurizers onthe H₂S adsorption, experiment prepared two kinds of differentdesulfurizers, the first preparation method is using AC as thecarrier,immersed with NaOH and CuPc respectively and jointly, then drythem off. The experiment investigate the penetration time of H₂S and thesaturated sulfur capacity variation regulations of different treatments. Itwas showed that loading0.025-0.250wt%CuPc could improve thepenetration time, however the saturated sulfur capacity didn’t have anysignificant differences compared to the Blank （AC without any treatment）.Loading10wt%NaOH, the penetration time was180min and thesaturated sulfur capacity was789.7mg/g, increasing by60%. Loading10wt%NaOH and0.250wt%CuPc, the penetration time were789.7mg/gand230min, increasing40min on the penetration time compared towhich of10wt%NaOH.The second method prepared AC based Fe/Zn desulfurizers byimpregnation roasting method using AC as the carrier, and the experiment had investigated the penetration time of H₂S and the saturated sulfurcapacity variation regulations of different treatments. It was showed thatloading5wt%iron oxide and2.5wt%zinc oxide could have the highestsaturated sulfur capacity, reaching as much as618.1mg/g, roastingtemperature have little effect on saturated sulfur capacity. XRD, XPSanalysis showed the desulfurization product was the non-crystalline sulfur,iron oxide and zinc oxide plays a catalytic role in the desulfurization, andBET analysis showed reactions can take place in the microporousstructure of AC.