Thermodynamics and Kinetics of Methanol Synthesis

Methanol is typicaUy synthesized in the gas phase over a heterogeneous catalyst from a gas containing a combination of hydrogen, carbon monoxide, and carbon dioxide. Synthesis can be from either of the foUowing chemical reactions 

On an industrial scale, methanol is synthesized from both reactions (1) and (2) simultaneous. Reaction (1) is exothermic, with a heat of reaction equal to 21.66 kcal/g-mol at 298K. Reaction (2) is Ukewise exothermic, with a heat of reaction equal to 11.83 kcal/g-moL Both reactions exhibit a decrease in volume (reduction in moles as the reaction proceeds to the ri t), and since both 

A reverse water-gas shift is also promoted over catalysts that promote methanol synthesis and thus must also be considered. This reaction proceeds according to 

Reaction (3) as it proceeds toward CO production is endothermic, with a heat of reaction equal to 9.84 kcal/g-moL In all the preceding cases, heats of reaction may be easily calculated at any temperature from heats of formation tables, where 

Reaction (2) is simply the sum of reactions (1) and (3), so even though all reactions progress simultaneously, only reactions (1) and (3) are considered independently, with maximum conversion of syngas to methanol limited by thermodynamic equilibrium. 

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