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A rotary drum filter with 30% submergence is used to filter concentrated aqueous slurry of calcium carbonate containing 15lb of solids per cubic foot of water. The pressure–drop is 2011Hg. If the filter cake contains 50% mixture (wet basis), calculate the filter area required to filter 10 gal/min of slurry. The filter cycle time is 5 min. The specific cake resistance depends on the pressure–drop as: α (ft/lb) = α (Δp)0.26, where α = 2.90×1010 Viscosity of the filtrate = 6.72×10-4 lb/ft-s. Density of calcium carbonate = 168.8 lb/ft3. Neglect filter medium resistance.

Correct Answer: ≅ 82 ft2
The expression for the production rate of cake.

Filtrate flow rate in case of a rotary drum vacuum filter (in which Rm c) is proportional to __________ and the cycle time (where, $$\mu $$ = filtrate viscosity, Rm = filter medium resistance, Rc = cake resistance ).

Drum X is 1/2 full of oil and drum Y, which has twice the capacity of drum X, is 2/3 full of oil. If all of the oil in drum X is poured into drum Y, then drum Y will be filled to what fraction of its capacity?

A dryer is used for drying pears which has initial moisture content of 70 % (wet basis) and final moisture content of 5 % (wet basis). An experimental drying curve for the product indicates that the critical moisture content is 25 % (wet basis) and the time for constant drying is 5 min. Can you estimate the total drying time for product?

Which of the following statement(s) is/are correct?
1. If sodium carbonate and washing soda is mixed in water the hardness of water can be removed.
2. The reaction of the chemicals produce sodium sulphate, sodium carbonate and insoluble calcium carbonate.
3. Magnesium sulphate chloride and magnesium carbonate is also produced.
Select the correct answer

Filtration rate through a filter cake is proportional to (where, S = filtering surface, R = specific cake resistance, $$\mu $$ = viscosity of the filtrate)

A slurry stream containing quartz is diverted into one litre density can. The time taken to fill up the can is measured as 5 sec. The pulp density is measured to be 1250 kg/m3. Calculate the mass flow rate of quartz within the slurry. Assuming the density of quartz is 2650kg/m3

Solution-1 containing 30% acetic acid and 100% nitrogen at the rate 10 Kg/min combines with Solution-2 containing 20% acetic acid and 10% nitrogen at the rate 20 Kg/min and Solution-3 containing 10% acetic acid and 30% nitrogen at the rate 30 Kg/min the product formed contains 20% acetic acid, what is the percentage of nitrogen in product?

In a batch process, the reaction takes place in the presence of an acid medium. The acid is drained from the reaction vessel at the rate of 15ml/s as a result of the density difference of the acid from the reacting component. To avoid wastage of acid, it is recycled to an acid tank which has 1000 L capacity. The acid drained from the reaction vessel, picks up 50 g/L solids from the reactor. Acid is fed once again to the process from acid tank. When the process is started, the acid is almost pure in the tank as a result of filtration. As the reaction proceeds, acid in the tank gets more and more contaminated with the solids. The concentration of the solids should not exceed 100 g/L from the process point of view. The batch time is 16h. Estimate whether the concentration of the solids will exceed 100g/L during the batch reaction.

If 100lb of black liquor containing 15lb of solids and 85lb of water is evaporated to 30lb; with a stream economy of 5 it would take 14lb of steam to remove the 70lb of water. The steam economy is about 0.8 per effect. An overall steam economy of the system is ?

In a laboratory test run, the rate of drying was found to be 0.5 × 10-3 kg/m2.s, when the moisture content reduced from 0.4 to 0.1 on dry basis. The critical moisture content of the material is 0.08 on a dry basis. A tray dryer is used to dry 100 kg (dry basis) of the same material under identical conditions. The surface area of the material is 0.04 m2/kg of dry solid. The time required (in seconds) to reduce the moisture content of the solids from 0.3 to 0.2 (dry basis) is