A gas containing water vapor has a dry-basis composition of 8.5 mole% CO, 10.5% COz, 0.5% O2, and 80.5% Nz. The gas leaves a catalyst regeneration unit at 620C and 1 atm with a dew point of 57C at a flow rate of 28.5 SCMH [m3 (STP)/h]. Valuable solid catalyst particles entrained in the gas are to be recovered in an electrostatic precipitator, but the gas must first be cooled to 425C to prevent damage to the precipitator electrodes. The cooling is accomplished by spraying water at 20C into the gas. (a) Use simultaneous material and energy balances on the spray cooler to calculate the required water feed rate (kg/h). Treat the spray cooler as adiabatic and neglect the heat transferred from the entrained solid particles as they cool. (b) In terms that a high school senior could understand, explain the operation of the spray cooler in this problem. (What happens when the cold water contacts the hot gas?)
LE08 Colligative Properties Wednesday, January 27, 2016 1:15 PM Colligative Properties are properties of solutions that depend on the particular solvent and on the concentration, buy they do not depend on the nature of the solute. When the solute and the solvent have identical IMFs, the enthalpy of solution is equal to zero (∆H solutio= 0) because making the solution has no effect on the PE of the molecules (ions) Mixing the solution WILL raise the entropy of the solution (∆S solutio= 0) Colligative properties ----> entropic effect - a result of the second law (entropy increase) • Vapor Pressure Lowering (Raoult's Law): vp ofa solution will be lower than the pure subs. This is the basis of understanding distillation. Same idea as bp elevation. • Boiling Po
