Removal Of Low Concentration H₂S With ACF Modified

A lot of CO₂ exhausted by industrial production, are abandoned because of lowconcentration H₂S, which can be availably removed by modified ACFs. There are advantagesof low cost, brief operation and high desulfurization efficiency. On the basis of thatbackground and the research been conducted before, the performances of modified ACFs bythe way of impregnation are studied mainly under the experiments of dynamic adsorption in afixed-bed reactor, using some methods of characterization. Five aspects about of the researchemphases, the desulfurization capabilities of modified ACFs, have been sdudiedcarefully. The core of the research are listed as follows:1 A study on the removal of low concentration H₂S by ACFs modified containing alkalinecompoundsThe ACF modified with K₂CO₃ showed better performance when removing H₂S in N₂,because the reaction of carbonic acid radicial and H₂S was faster than the reactions of otherradicals and H₂S; while ACF modified with KOH when removing H₂S in CO₂, because theacidity of CO₂, which was disandvantage of the adsorption and desorption of H₂S on ACF,can be settled by ACF having higher alkalescence. The O₂ in the feed gas was advantageousto the performance of desulfurization.2 A study of the removal of low concentration H₂S by ACFs modified with transitional metalsIt showed that ACFs modified Cu²⁺,Zn²⁺,Ag⁺ present better performances of removingH₂S; and the preheating can preduce the activated oxygenous agents on ACF, which are goodto removing H₂S; and the increase of the reaction temperature improves the performance ofdesulfurization of ACF modified with transitional metals; and the O₂ in the feed gas improvedthe efficiency of desulfurization by the mechanism of the oxidation with the catalysis of ACF,while the CO₂ in the feed gas decreased the efficiency of desulfurization of modified ACFbecause of its acidity and its competitive adsorption with H₂S.3 A study of removal of low concentration H₂S using ACFs modified withferric salts atambient temperatureIt was found that after thermal treatment, ACF impregnated iron nitrate presented a greatefficiency of adsorbing H₂S at room temperature. Also it showed that the predominant factorsinvolved oxygenous structure, relative humidity, pore structure and high specific area ofadsorbent. Besides, the amount of iron oxide and surface alkalescence are subsidiary factors. 4 A study of the removal of low concentration H₂S in the feed gas containing CO₂ withmodified ACFIt showed that the performance of desulfurization of ACF modified in CO₂ can beimproved by increasing oxygenous structures and alkalescence. In the ambienttemperature(298K), the acidity of CO₂ was the most important factor; while in the hightemperature, the oxidation of CO₂ was the most important factor. With the reactiontemperature increasing, more oxygenous structures were produced by the reaction of CO₂ andACF, so that the presence of CO₂ was good to the removal of H₂S. 573K was the appropriatereaction temperature.5 A study of the regeneration methods for used modified ACF by removing low concentrationH₂SIt showed that the gas heating regeneration method was more effective than the solventregeneration method. The differences of the effects of different regeneration methods wereinduced by the different reaction mechanisms of desulfurization using different modified ACFsand the different regeneration mechanisms of regeneration methods.Though the studies above, the mechanism of removing H₂S with modified ACF and howall the factors affect on the desulfurization performance were understood more clearly. Thesebasal data were very useful to how to enhance the sulfur capacity of ACF and how to realizethe recycling use of them in the desulfurization industry.