Converting Syngas to Ethanol
A thermodynamic analysis is essential to understanding the equilibrium limits in converting syngas to ethanol. This Demonstration considers these five chemical species: (ethanol), and (syngas), , and . The feed composition is such that the molar ratio is 1.[more]
The Demonstration plots the mole and carbon fractions (defined in the Details section) versus the temperature ( in ), for user-set values of the pressure ( in bars). In addition, the results of our calculations are compared with those obtained with Aspen Plus (chemical process optimization software) using the built-in module entitled RGIBBS. The Gibbs free energy minimization and the Peng–Robinson equation of state are employed in both calculations. Excellent agreement is observed for equal to 1, 10, and 100 bars. Since the conversion of syngas to ethanol is highly exothermic and proceeds with volume contraction, high yields of ethanol are obtained at low temperature or high pressure.[less]
Let , , and be the mole fractions of (ethanol), , and , respectively. Then the carbon fractions are given by:
(for ethanol), (for ), and (for ).