2.3 Kg/s of solid containing 0.55 Kg/s soluble material is to be washed with 2.8 Kg/s pure solvent in a counter – current unit . The final residue is to contain not more than 0.1% solute when dried . Find the number of stages given that the amount of solution in under flow varies with solute concentration according to the relation : W = 0.2 X + 0.3 , Also find the concentration and quantities in and out from each stage .

Consider a solid sphere, of radius R, which is placed in a large body of unstirred, aqueous solution, as shown in Figure 1. The dissolution of the solid A, is slow enough that quasi-steady-state can be assumed. Given the solubility of A in the solution is CA* at the surface of the sphere and assume there is a bulk diffusion in the solution (i.e. the term yA(NA+Nu) is not zero). 1.) Derive an expression for the concentration distribution of A in the solution; and 2.) develop a mathematical relationship for molar flow rate of A, entering the solution at the surface of the sphere. FLUID SOLID 'A' &r Rs

A double effect evaporator is used to concentrate an 18% CuSO4 solution. At the end of evaporation, 26,000 kg/h of 50% CuSO4 solution were obtained. If the water evaporated in the second effect is half the water evaporated in the first effect, determine: a) The amount of solution fed into the first effect. b) The amount of water evaporated in the first and second effect. c) The amount of solution fed into the second effect, as well as its composition. Problem diagram 18% CuSO4 82% H₂O M₁ M₂ M3 X CuSO4 Y H₂O A 2 M4 = 0.5 M₂ M5 H₂O steam M6 M2 M6 is the water that condenses 26 000 kg/hr 50% CuSO4 50% H2₂O

Consider a diffusion process in a semi-infinite solid with a source at x=0 mm, the concentration of the diffusing species is 2 nm-3 at x=5 mm and t=1 hr (since the start of the process). At what time the concentration at x=15 mm will reach 3 nm-3 ?

A new type of porous material serves as food packaging film, as shown in the figure below. The film rests on a nonporous metal plate. The packaging film is 0.20 cm thick (2.0 mm). The food contains liquid water, which exerts a vapor pressure of 0.030 atm at 25°C. At 25°C, the effective diffusion coefficient of water vapor in the porous film is 1.3 x 10^-4 cm/s, and the molecular diffusion coefficient of water vapor in air is 0.26 cm/s. You may assume that the total system pressure is constant at 1.0 atm, and initially, the gas space of the porous film contains air and no water vapor. How long will it take for the water vapor to achieve a partial pressure of 0.0150 atm at the back surface of the film (z = 0) at 25°C?

The aqueous acetone solution is mixed with Methyl isobutyl (MIB) solvent containing 3% acetone by mass. The flow rates of the upper and lower currents leaving the system are 1000 kg/h and 400 kg/h, respectively. System the proportion of acetone in the upper and lower leaving current is 15% and 10% by weight, respectively. The phase separation of the refinate and the extract takes place. According to this a. Calculate the composition and amount of the aqueous acetone solution entering the system. b. Calculate the amount of Methyl isobutyl ketone (MIBK) solvent containing 3% acetone sent to the system. extract phase Data; Methyl isobutyl (MIB 0.05 0.05 0.06 0.07 0.08 0.09 0.20 XA Acetone 0 0.05 0.15 0.20 0.25 0.35 0.43 XC. Methyl isobutyl (MIB 0.95 0.94 0.89 0.84 0.79 Refining phase 0.69 0.59 YA Acetone 0 0.02 0.10 0.15 0.20 0.30 0.40 YC

Consider a metal spherical vessel, with an inner diameter of 5 m and a thickness of 3 mm, containing hydrogen gas at 2000 kPa. The vessel is situated in a room with atmospheric air at 1 atm. The ventilation system for the room can keep the air fresh, provided that the rate of hydrogen leakage is below 5 μg/s. If the diffusion coefficient and solubility of hydrogen gas in the metal vessel are 1.5 × 10−12 m2/s and 0.005 kmol/m3·bar, respectively, determine whether the vessel is safely containing the hydrogen gas

A wet sphere of gelatin gel at a temperature of 20 "C contains a uniform concentration of urea of 0.05 kg mol/m'. The sphere has a diameter of 16 mm. The sphere is suddenly immersed in turbulent water which initially contains urea of concentration 0.1 kg mol/m'. The diffusion coefficient of the urea in the gelatin gel is 8.59 * 10*" m/s. The convective mass transfer coefficient ke is 1.07375 x 10 m/s and the equilibrium distribution coefficient K is 1. For radial mass transfer only, listing your assumptions, calculate, (a) the concentration at a distance of 4,8 mm from the midpoint of the sphere after 25.87 hours of mass transfer. (b) the time by which the concentration, c, at the centre of the sphere is 0.09975 kg mol/m3

Find the diffusion coefficient of ammonia-hydrogen system at 25 °C and atmospheric pressure and correct its value for 85 °C and compare it with experimental values.

A quiescent body of water has a depth of 600 mm. The DO level at the bottom after 16 days is 3.5 mg/l when the surface is exposed to the atmosphere at a temperature of 25o Determine the DO of the water body. The saturated DO at 25oC is 8.5 mg/l and the diffusion coefficient (kd) at 25oC is 2.5 x 10-3 mm2/s.