Problem 1 (50 pts). Carbon disulfide, CS2, used as a solvent in a chemical plant, is evaporated from the product in a drier into an inert gas (essentially N2 ) in order to avoid an explosion hazard. The vapor- N2 mixture is to be scrubbed with an absorbent hydrocarbon oil, which will be subsequently steam-stripped to recover the CS2 The CS2N2 mixture has a partial pressure of CS2 equal to 50mmHg at 24C and is to be blown into the absorber at essentially standard atmospheric pressure at the expected rate of 0.40m3/s. The vapor content of the gas is to be reduced to 0.5%. The absorption oil has an average molecular weight of 180 , viscosity of 2cP, and specific gravity of 0.81 at 24C. The oil enters the absorber essentially stripped of all CS2, and solutions of oil and CS2, while not actually ideal, follow Henry's law. The Henry's law constant is 346mmHg/mole fraction. Assume isothermal operation. Show a detailed schematic, a list of assumptions made, and all equations and necessary derivations. Note: You are required to provide detailed step by step calculations and your own plot figures to receive credit. (a) Determine the minimum liquid/gas ratio (i.e., LS/GS ). (b) Determine the kilograms of oil to enter the absorber per hour. (c) Determine the number of theoretical trays required. Do not use the Kremser equations. Problem 1 (50 pts). Carbon disulfide, CS2, used as a solvent in a chemical plant, is evaporated from the product in a drier into an inert gas (essentially N2 ) in order to avoid an explosion hazard. The vapor- N2 mixture is to be scrubbed with an absorbent hydrocarbon oil, which will be subsequently steam-stripped to recover the CS2 The CS2N2 mixture has a partial pressure of CS2 equal to 50mmHg at 24C and is to be blown into the absorber at essentially standard atmospheric pressure at the expected rate of 0.40m3/s. The vapor content of the gas is to be reduced to 0.5%. The absorption oil has an average molecular weight of 180 , viscosity of 2cP, and specific gravity of 0.81 at 24C. The oil enters the absorber essentially stripped of all CS2, and solutions of oil and CS2, while not actually ideal, follow Henry's law. The Henry's law constant is 346mmHg/mole fraction. Assume isothermal operation. Show a detailed schematic, a list of assumptions made, and all equations and necessary derivations. Note: You are required to provide detailed step by step calculations and your own plot figures to receive credit. (a) Determine the minimum liquid/gas ratio (i.e., LS/GS ). (b) Determine the kilograms of oil to enter the absorber per hour. (c) Determine the number of theoretical trays required. Do not use the Kremser equations
