Sodium carbonate is recovered as decahydrate from 1000kg of 5% solution of sodium carbonate in water. If it is desired that 95% of Na2CO3 is to be recovered as decahydrate by cooling to 278 K, determine the following: a) the mass of water evaporated (b) the mass of crystals obtained (Na2CO3 ∙ 10H2O). The solubility of Na2CO3 in water at 278K is 9.0% (weight)
1. Sodium carbonate is recovered as decahydrate from 1000kg of 5% solution of sodium carbonate in water. If it is desired that 95% of Na2CO3 is to be recovered as decahydrate by cooling to 278 K, determine the following: a) the mass of water evaporated (b) the mass of crystals obtained (Na2CO3 ∙ 10H2O). The solubility of Na2CO3 in water at 278K is 9.0% (weight)
2. A copra batch contains 44% oil and is to be extracted with n-hexane. The extracted meal contains 0.07 kg of oil/kg oil free matter and the mass fraction of n-hexane in it is 0.05. The extract contains 49% n- hexane. If 10,000 kg of copra are to be processed, how many kg of n-hexane are required and the determine the amount of extract.
3. Absorption of sulphur dioxide is carried out in a packed tower. Gas containing 14.8% sulphur dioxide and the rest inert gases enters the tower while the leaving gases contains 1% sulphur dioxide. Water flows at the rate of 1m3/min. The tower handles 7380 m3/hr of gas at 303K and 1 bar. Find the kmoles of sulphur dioxide absorbed in the effluent from the tower. Also find the volume (m3) of the gases leaving the tower at 0.95 bar and 2983K.
4. A tunnel drier is used to dry an organic paint pigment. 1000 lbs /hr of pigment containing 10% water is to be dried to 0.50% water. The pigment is passed counter current to air which enters at 760 mmHg, 1400 F and 10% humidity. The leaving air is at 750 mmHg, 950 F and 70% humidity.
Note: entering air @ 760 mmHg and 170 degrees F , H = 0.012 lbs H2O / lbs dry air.
leaving air at 750mmHg, 950 F , H = 0.026 lbs H2O / lbs dry air.
Determine the following:
a. How many pounds of water are removed from 1000 lbs of pigment fed to the drier?
b. How many pounds of air are entering the drier?
c. How many pounds of air are leaving the drier?
d. What is the volume (ft3) of air entering the drier?
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