Chapter 6, Problem 6.33P

A gas stream containing 40.0 mole% hydrogen, 35.0% carbon monoxide, 20.0% carbon dioxide, and 5.0% methane is cooled from 1000°C to 10°C at a constant absolute pressure of 35 atm. Gas enters the cooler at 120 m³/min, and upon leaving the cooler, is fed to an absorber where it is contacted with refrigerated liquid methanol that enters the absorber at a molar ?ow rate 1.2 times that of the inlet gas and at — 155°C. Essentially all of the CO₂is absorbed, as is 98% of the methane and an inconsequential amount of the other components of the feed gas. The gas leaving the absorber is saturated with methanol at −12°C and is fed to a reactor for further processing.

(a) Calculate the volumetric ?ow rate of methanol entering the absorber (m³/min) and the molar ?ow rate of methanol in the gas leaving the absorber. D0 not assume ideal-gas behavior when doing PVT calculations.

(b) List and explain at least three hazards associated with the system described.

(c) One of the possible uses of the product gas is as a feed to a reactor in which the water-gas shift reaction takes place: ${\text{H}}_{\text{2}}{\text{+CO}}_{\text{2}}\rightleftharpoons {\text{H}}_{\text{2}}\text{O+CO}$. Explain the effect of removing CO₂before introducing the feed to the reactor.