Air Condenser Distilote Air 0.995 WAWoter 0.005 Water (100%) Acetone 0.99 Water 0.01 1.00 1.00 Adsorber Column Distillation Column 8 2 Bottom Acetone 0.04 Water 0.96 1.00 400 kg/hr Acefone 0.19 Wafer 0.81 1.00 Entering Gos Air 0.95 Acetone 0.03 Water 0.02 1.00

Steel surface can be hardened by carburization. Such process is done at 1000°C and the concentration gradient (dc/dx) is -8.23x1029 atoms/m4.  The coefficient of diffusion (D0) for Fe is 20x10-6 m2/s (See table 1). Estimate the flux of carbon atoms into the steel in this process.

The surface of a 2.5 mm thick ammonia (A) (NH3) – water (B) (H2O) solution at 298 K is in contact with an organic liquid. At the interface (the surface in contact with the organic liquid and water), the equilibrium concentration of ammonia in water is kept constant at 3% by weight (aqueous solution density at this first point, 992.5 kg/m3). 2.5 mm away, at the other border of the film, the concentration of ammonia in water is 12% by weight (the density of the aqueous solution at this second point is 962.3 kg/m3). The water and organic phase are insoluble in each other. (MA = 17.03 kg/kgmol, MB = 18 kg/kgmol) (Assume the ammonia-water solution is 100 kg.)(a) Calculate the diffusibility of ammonia in water using the Wilke-Chang correlation. (Water viscosity at 298 K, B = 0.8937 x 10-3 Pa.s)(b) Calculate the steady state NA flux.(c) Calculate and explain the flux NB.

NaCl crystal is created from seawater within a series of evaporation and crystallization. A feed of 10 tons/hr of seawater containing 3.6% NaCl was mixed with a recycled stream of saturated brine solution at 40 Celcius before being fed to an evaporator where it is heated to 120 Celcius. The concentrated brine solution produced from the evaporator is 54% NaCl. This brine solution was fed to a crystallizer where it was cooled down to 40 Celcius to crystallize the NaCl. The crystals produced are 96.5% NaCl. The excess saturated liquor was mixed to the fresh seawater for recycle. The solubility of NaCl at 40 Celcius is 0.366 kg of water (H2O). Calculate: NaCI Crystals + H,0 Saturated Crystallizer Brine at 40°C Evaporator Mixer Seawater Concentrated Brine at 120°C Water Vapor a) crystals production rate kg/hr b) concentrated brine solution in kg/hr c) recycle stream flow rate in kg/hr