Exercise 7 Text

Pagina 1

-INDUSTRIAL ORGANIC CHEMISTRY – EXERCISE 7 Proof test Methanol is produced according to the layout reported on the left. The fresh feed (1) is split into two stream (2) and (7). Stream (2) is fed to the first reactor (R-1). The stream leaving the reactor (3) is sent to the methanol separator (F-1). The gas stream leaving the separator (4) is then mixed with stream (7) and fed to the second reactor (R-2). By assuming: • Both the methanol synthesis reaction and the WGS reaction occur in reactors R-1 and R-2 • The volumetric behavior of the gas mixture in the react ors R-1 e R-2 is of ideal mixture of real gas. In this view, a value of 𝐾𝜙 𝑀𝑒𝑂𝐻 = 𝜙𝑀𝑒𝑂𝐻 𝜙𝐻2 2 𝜙𝐶𝑂 = 0.9 e 𝐾𝜙 𝑊𝐺𝑆 = 𝜙𝐶𝑂2𝜙𝐻2 𝜙𝐻2𝑂𝜙𝐶𝑂 = 1.05 can be assumed for the evaluation of the 𝐾𝑝 for the methanol synthesis and for the WGS. • The pressure in each unit is equal to 100 bar and pressure drops are negligible • Reactor R-1 achieves thermodynamic equilibrium • The 90% of the CO reacted in reactor R-1 produces methanol • In the separator, thermodynamic equilibrium is achieved • In the separator, the gas mixture is ideal and consists of ideal gas. The liquid mixture is ideal and the Poynting correction is negligible. As a first approximation, the Henry’s constant can be considered constant with temperature. The enthalpy of the gas species dissolve d in the liquid can be assumed as negligible • The separator is designed to recover in the liquid stream (6) the 60% of the methanol contained in stream (3) • The reactor R-2 is adiabatic • The conversion of CO in the second reactor is equal to 4 8 %, whereas the overall yield of methanol with respect to CO2 is 70 % It is required to evaluate: 1. The temperature and the composition (molar fractions) of the stream leaving reactor R-1 2. The heat removed per mole of stream…