Chemical Engineering

1. A stream containing 4wt% chromium (Cr), is contained in the wastewater from an absorber. The wastewater stream is fed to a treatment unit that removes 95% of the chromium in the feed and recycles it to the plant. The residual liquid stream leaving the treatment unit is sent to a waste lagoon. The treatment unit has a maximum capacity of 4500 kg wastewater/hr. If wastewater leaves the finishing plant at a rate higher than the capacity of the treatment unit, the excess (anything over 4500kg/hr) bypasses the unit and combines with the residual liquid leaving the unit, and the combined stream goes to the lagoon.

a) Without assuming a basis of calculation, draw and label a flowchart for the process.

b) Wastewater leaves the finishing plant at a rate between 1000kg/hr and 10000kg/hr. In increments of 1000kg/h, cacluate the flow rate of liquid to the waste lagoon, and the mass fraction of chromium in the liquid over the given range. Using a graphing program (MATLAB, Excel), generate a plot of the flow rate as a function of mass fraction.