A groundwater contains the following anion concentration ex- changer (NO3−N = 18 mg/L, SO42− = 50 mg/L, Cl− = 35 mg/L, and HCO − = 85 mg/L). Assuming nitrate is removed completely 3 from solution, calculate the equilibrium exchange capacity for each ion, and the maximum volume of water that can be treated per liter of resin, assuming equilibrium conditions. Assume total resin capacity of the SBA is equal to 1.4 eq/L.

Air is to be cooled in the evaporator section of a refrigerator by passing it over a bank of 0.8-cm-outer-diameter and 0.4-m-long tubes inside which the refrigerant is evaporating at -20°c. air approaches the tube bank in the normal direction at 0°c and 1 atm with a mean velocity of 4 m/s. the tubes are arranged in-line with longitudinal and transverse pitches of sl- st 1.5 cm. there are 30 rows in the flow direction with 15 tubes in each row. determine (a) the refrigeration capacity of this system and (b) pressure drop across the tube bank. evaluate the air properties at an assumed mean temperature of -5°c and 1 atm. is this a good assumption?