- Direct Dehydrogenation Of Ethylbenzene To Styrene Is Carried Out In The Vapor Phase With Steam Over A Catalyst Consistin 1 (126.1 KiB) Viewed 7 times
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Direct dehydrogenation of ethylbenzene to styrene is carried out in the vapor phase with steam over a catalyst consisting primarily of iron oxide. The reaction is endothermic, and can be accomplished either adiabatically or isothermally. Both methods are used in practice. The major reaction is the reversible, endothermic conversion of ethylbenzene to styrene and hydrogen: C6H5CH2CH3 C6HsCHCH2 + H2 AH= 124.9 kJ/mol Competing thermal reactions degrade ethylbenzene to benzene C6H5CH2CH3C6H6+ C2H4 AH = 101.8 kJ/mol Styrene also reacts catalytically to toluene: C6H5CH2CH3 + H2 C6H5CH3 + CH4 AH=-64.5 kJ/mol The reactions take place at 620°C. The costs are as shown in Table 1. The production rate of styrene is 200 mol/h. Chemical name Formula Cost ($/kmol) Ethylbenzene C6H5CH2CH3 57.1 Styrene C6H5CHCH2 75.9 Benzene C6H6 32.8 Toluene C6H5CH3 25.8 Hydrogen H₂ 1.2 (as fuel) Methane CH4 4.0 (as fuel) Ethylene C₂H4 6.7 (as fuel) Correlation for the product selectivity and distribution are given as following equations. mol Styrene formed 0.2 S= = 1- mol Ethylbenzene converted (1-x)0.5 Mol Benzene = 0.033x -0.215x² +2.547x³ Mol Styrene 1. Calculate the Economic Potential (EP) in $/kg at 75% of conversion. All by-products are saleable. (12)