Repeat Problem 5-8 using the three bed system designed in Problem 5-4 . Problem 5-8Co...

Repeat Problem 5-8 using the three bed system designed in Problem 5-4 .

Problem 5-8

Continuing the design of the ion exchange column for the Village of Calcite, provide the following for the two-bed system that will operate in parallel with staggered regeneration cycles:

a. Surface loading rate (m³/d · m² )

b. Height and diameter of the resin bed

c. Empty bed contact time (min)

d. Service flow rate (m³/d · m³ )

e. Height and diameter of the column vessel

f. Pressure drop

Assume the density of the resin is 830 kg/m³ (moist), a resin height less than or equal to 4.0 m, and that 50% expansion of the bed will be used during backwash. The pressure drop across the bed should be less than 140 kPa.

Problem 5-4

Repeat Problem 5-2 assuming a three column system in series and operation of the “lead” column until the bed is exhausted. Assume the total out-of-service time is two hours.

Problem 5-2

A pilot scale ion exchange column was used to develop design data for a softening system for the Village of Calcite. The data are shown below. The design flow rate is 4,000 m³/d. The design final hardness is 120 mg/L as CaCO₃ . Regeneration is to be once per day. The manufacturer’s operating capacity to breakthrough is 60%. Assume a two-column system: one in service and one in regeneration or standby. Also assume that there is no leakage before breakthrough. Use the mass balance technique to determine the mass of resin that will be required.