The Schematic Below Shows A Waste Water Treatment Process Associated With A Clarifier The Goal Of This Waste Water Trea 1 (241.95 KiB) Viewed 32 times
The schematic below shows a waste water treatment process associated with a clarifier. The goal of this waste water treatment process is to decrease the initial concentration of TCE content (initial concentration is 50 mole TCE/m³) to 10 mole TCE/m³ using a stream of fresh air. The clarifier operates at 1.0 atm and a constant temperature of 20 °C. In an independent pilot plant study of TCE, the liquid film mass transfer coefficient for the clarifier was kx = 200 mole/m²-sec, whereas the gas film mass transfer coefficient for the clarifier was k, = 0.1 mole/m²-sec. Equilibrium data for the air-TCE-water system at 20 °C is represented by Henry's Law with an equilibrium proportionality constant of H=9.9 atm L/mol. Cross-section view of a cylindrical tank, D=20m Air in Air out Waste water in 10 mole TCE/m³ Well mixed waste water Waste water out A. What is the direction of the flux of TCE? Would this be a liquid stripping process or a gas absorption process? B. If the system is stationary (no flow of air or liquid). In this case: i) Would this system reach steady state or equilibrium?
Continuing with the stationary system (no flow of air or liquid). In this case: ii) If the system was left undisturbed for a long time and the bulk concentration of TCE in the liquid was kept at 10 mole TCE/m³ what would be the partial pressure of TCE in the gas phase? iii) What would be the total concentration of the liquid phase assuming it was only water and TCE?
iv) If the partial pressure of TCE in the gas phase was 0.5 atm and the system was left undisturbed for a long time what would be the bulk concentration of TCE in the liquid? v) Would partial pressure of 0.5 atm TCE be a good operations conditions to reach the goal of less than 10 mole TCE/m³ in the effluent?
C. Estimate K₁ or Kx for this system, would it be gas or liquid phase resistant? D. How much water with less than 10 mole/m³ TCE in the effluent stream could you produce in the units of m³/s if the partial pressure of TCE in the gasphase is 0.04 atm and the inlet concentration is 50 mol/m³?
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