Study On Desulfurization Of Organic Thiophenic Sulfur In Gasoline With Catalytic Oxidation/adsorption

With the acceleration of the process of human society modernization, the consumption ofgasoline is increasing day byday, and the sulfur compounds produced by gasoline combustioncauses serious environmental pollution and gives a great threat to human health. So the deepdesulfurization of gasoline has become a very challenging research subject for petroleumrefining industry worldwide.The removal effects of different organic sulfurs using catalyzed oxidation desulfurizationmethod and adsorptive desulfurization method are studied in this paper for deepdesulfurization of gasoline, mainly concerned with the preparation of phosphotungstic acidcatalyst loaded on activated carbon(HPW/AC) and catalytic oxidation of organic sulfurs ingasoline with this catalyst; discussion of the effect of various hydorcabron compounds foroxidation desulfurization; research of different oxidation methods modifying high surfacearea activated carbon for desulfurization of gasoline and adsorptive desulfurization fromgasoline with fixed bed.The major contributions of this paper are as follows:1. Supported catalyst(HPW/AC) has been prepared in this paper by impregnation methodand the effects of catalyzed oxidation desulfurization of organic thiophenic sulfurs in gasolinewith this catalyst are also studied. Results shows the supported catalyst(HPW/AC) has morecatalytic activity than unsupported catalyst(HPW), and the desulfurizaiton rate of thecommercial gasoline can achieve 32%, when the commercial gasoline (20 ml) with H2O2(4ml), CTAB (0.05 g) and HPW/AC (0.5 g) is stirred at 80℃for 2h. The oxidative reactivity oforganic sulfurs in gasoline decreases with the decrease of electron density. The mercaptan,sulfide and benzothiophene (BT) can be oxidized easily due to their high electron density, butthe thiophene (T) and alkylated thiophene (Cn-T) are very difficult to remove by catalyticoxidation due to their low electron density, some of which almost can not be oxidized, such asT,C1-T and C2-T.2. The dynamic experiments of catalytic oxidation of thiophene with H2O2-HPW/AC-CTAB system are investigated and results show when the reaction temperature is 90℃, thedesulfurizaiton rate of thiophene reaches 89.07%, and the activated energy of catalyst(HPW/AC) is 61.95 kJ/mol. The desulfurizaiton rate of thiophene decreases obviously whenhydrocarbon compounds like xylene, cyclohexene and 1,7- octadiene are added intothiophene. Especially when the volume fraction of cyclohexene reaches 15%, thedesulfurizaiton rate of thiophene decreases to 7%. The valuable data for deep desulfurizationof real gasoline are provided bythese experiments. 3. The method of modifying high surface area activated carbon by ozone under differentliquid oxidation media is proposed in this work. Results show the adsorption capacity of highsurface area activated carbon modified by this method can achieve 79.3 mmol/kg, increasing41% compared with initial activated carbon, and ozone oxidation method hardly loses itsmass, compared with traditional thermal oxidation method which can lose its mass by 92.4%at 350℃.4. Column experiments are carried out for obtaining ultra-clean model fuel in this work.The results indicates adsorption capacity of per kilogram of modified activated carbon is 64mg-S/kg-adsorbent, which provides some valuable reference for studying absorbent materialsand design of fixed beds.