Influence of the preparation conditions of MgAlCe catalysts on the catalytic hydrolysis of carbonyl sulfide at low temperature

Abstract

Highlights ►The cost-effective MgAlCe catalysts have been prepared and characterized.►The catalysts had a permanent service life and a high COS hydrolysis activity at low temperature. ►To form a complete catalyst preparation process.►Effect of the proportions of Al/Ce, calcination temperatures, hydro-thermal temperatures and pH on catalytic activity were studied. Graphical abstractCatalytic hydrolysis of carbonyl sulfide (COS) at 50 o C over Mg-Al-Ce mixed oxides derived from hydrotalcite-like compounds were studied. MgAlCe hydrotalcite-like compounds (HTLCs) were synthesized by co-precipitation methods based on different proportions of Al/Ce. Metal oxides derived from HTLCs were tested for the catalytic hydrolysis of carbonyl sulfide (COS) at the relatively low temperature of 50 o C. The removal effect of COS strongly correlated to the proportions of Al/Ce, synthesis pH and calcination temperatures. Hydro-thermal temperatures were applied to improve the crystalline of material while catalysts were characterized by Xray diffraction (XRD), Thermogravimetry (TG) and Brunauer-Emmett-Teller (BET) methods. Results may contribute to more fully understanding the effect of preparation conditions for hydrolysis of COS. Optimum preparation conditions were found to be: proportions of Al/Ce equal to 16/1, synthesis pH of 8, hydro-thermal temperature of 140 o C, and calcination temperature of 600 o C. The catalyst prepared under these conditions demonstrated an impressive efficiency (100%) and sustained approximately 80 minutes at a relatively low temperature of 50 o C and space velocity of 5000h -1 .

Experimental and Theoretical Studies on the Influence of Carrier Gas for COS Catalytic Hydrolysis over MgAlCe Composite Oxides

“…MgAlCeO x is synthesized through our previous method. 17 The preparation conditions are reproduced below. The atomic ratio of Mg/Al/Ce is 34:16:1, and the mole ratio of NaOH/Na 2 CO 3 is 1:1.…”

“…The catalytic activity test system is same as our previous system. 17 In this study, the reaction conditions are as follows: 470 ppm COS; 2.67% relative humidity (RH); 5000 h –1 gas hourly space velocity (GHSV); and 50 °C reaction temperature. COS and H 2 S concentrations of the gas feed and effluent from the reactor are analyzed using a FULI 9790II gas chromatography.…”

“…So far, catalytic hydrolysis method is regarded as the suitable way for the removal of COS because of high removal efficiency, low operation cost, and mild reaction condition. − The hydrolysis products of COS are CO 2 and H 2 S. − H 2 S can be removed more easily than COS. In our previous study, hydrotalcite-like compounds-derived MgAlCe composite oxides (MgAlCeO x ) show 100% COS removal efficiency under N 2 atmosphere condition . However, the main component in industrial gas is CO.…”

“…In our previous study, hydrotalcite-like compounds-derived MgAlCe composite oxides (MgAlCeO x ) show 100% COS removal efficiency under N 2 atmosphere condition. 17 However, the main component in industrial gas is CO. The carrier gas condition can change the removal efficiency and process.…”

Ion-Exchanged Zeolites Y for Selective Adsorption of Methyl Mercaptan from Natural Gas: Experimental Performance Evaluation and Computational Mechanism Explorations

“…However, they have been proven to be less effective for removing organosulfurs from natural gas . An available technique for the removal of COS is based on catalytic hydrolysis, which can convert COS to H 2 S and CO 2 . − Hence, catalytic hydrolysis coupled with amine treating can easily remove COS from natural gas. As a result, the desulfurization performance for natural gas can be largely determined by the removal efficiency of mercaptans.…”