Methanol may be produced by the reaction of carbon dioxide and hydrogen. CO2 + 3
ID: 904010 • Letter: M
Question
Methanol may be produced by the reaction of carbon dioxide and hydrogen. CO2 + 3H2 rightarrow CH3OH + H2O The fresh feed to the process contains hydrogen and carbon dioxide in stoichiometric proportion, and inerts (I). The reactor effluent passes to a condenser, which removes essentially all of the methanol and water formed, none of the reactants or inerts. The latter substances are recycled to the reactor after mixing with the fresh feed. To avoid build-up of the inerts in the system, a purge stream is withdrawn from the recycle. The fractional split is 0.16. The feed to the reactor has an overall flow rate of 6803 mol/h, which contains 2% inerts. The single-pass conversion of the reactor is 60%. Calculate the molar flow rates of hydrogen and carbon dioxide in the fresh feed, and the production rate of methanol.
Explanation / Answer
Answer:
Given reaction:
CO2 + 3H2 CH3OH + H2O
From the reaction it can be noted that 1 mole of CO2 reacts with 3 moles of H2 to produce 1 mole of CH3OH.
Given overall flow rate of reaction = 6803 mol/h
And capacity of reactor is given as 60%
Thus flow rate of reaction as per reactor capacity = (6803*60)/100
= 4081.8 mol/h
But reaction is consuming CO2 and H2 in 1:3 ratio. So, total number of moles = 1 +3 = 4
Flow rate for each mole of reaction = 4081.8/4
=1020.45 mol/h
Flow rate of CO2 = 1*1020.45 = 1020.45 mol/h
Flow rate of H2 = 3*1020.45 = 3061.35 mol/h