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00000CH201121902

i) The absolute humidity

ii) The percent humidity

iii) Enthalpy of wet air

iv) Humid volume
A counter current extractor is employed to extract oil meal using ethyl ether as
the solvent. The fresh meal is charged to the unit at a rate of 1000 kg/h and
contains 25% oil. Pure solvent enters the bottom of the extractor. The overflow
from the unit contains 60% oil. The underflow contains 0.25 kg of solvent per
kg of oil free solids and the concentration of the oil in the underflow is 12%.
Calculate: (i) the solvent requirement and (ii) the percentage of oil recovery.

PART C
Answer any two full questions, each carries 20 marks.
Define the terms: (i) conversion, (ii) yield and (111) % excess.
Flue gas produced by burning methane has following composition on dry basis:
(02 - 10%, 02 - 2.37 %, CO - 0.53%, N2 - 87.1%

Calculate the composition of feed.
CO at 1000 K is burned with 90 % excess air at 800 K. The products of
combustion leave the reaction chamber at 1250 K. Calculate the heat evolved in
the reaction chamber per mol of CO burned. The standard heat of reaction at
298K is -282.99 kJ/mol CO. The mean specific heat applicable in the
temperature range are 29.38, 49.91, 33.13 and 31.43 J/mol.K for CO, (02, 02
and N> respectively.
The fuel oil analyzing 85 % (weight) C and 15 % (weight) H is oxidised with 50
% excess air. For the oxidation of 100 kg of oil, calculate: (i) the air requirement
in kilograms, ii) the composition of flue gas iii) the average Molecular weight of
the gas.
State Hess’s law of constant heat summation. Give an example
A gas mixture consisting of 20 % ethane and 80 % oxygen at 298 K is burned
completely at 298 K. The mean heat capacities in J/mol K are 54.56 for CO»,
43.02 for water vapour and 35.52 for oxygen. The standard heat of reaction is
-1428 kJ/mol of ethane at 298 K. Determine the theoretical flame temperature
When coal containing 74% C, 14.9% H and 11.1% ash is burned. It gives a flue
gas containing 12.5% (02, 1% CO, 1.5% 02 and 85% No» on dry basis.

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