A methanol-synthesis reactor is fed with a gas stream at 220°C consisting of 5.0 mole% methane, 25.0% CO, 5.0% CO2, and the remainder hydrogen. The reactor and feed stream are at 7.5 MPa. The primary equilibrium reaction in the reactor is CO+2H2 --> CH3OH. The product stream may be assumed to reach equilibrium at 250°C.
Assume the equilibrium constant can be modeled by:
K = (yCH3OHyH2)/(yCO(yH2)2P2) = exp(21.225 + (9146.6/T)-7.492ln(T)+4.064x10-3T+7.2x10-8T2)
(a) Determine the composition (mole fractions) of the product stream and the percentage conversions of CO and H2.
(b) Neglecting the effect of pressure on enthalpies, estimate the amount of heat (kJ/mol feed gas) that must be added to or removed from (state which) the reactor.
(c) Calculate the extent of reaction and heat removal rate (kJ/mol feed) for reactor temperatures between 200°C and 400°C in 50°C increments. Use these results to obtain an estimate of the adiabatic reaction temperature.
(d) How does the required heat rate change if the pressure of the reactor increases to 15 MPa?