University Of Pune Question Paper
S.E. (Petrochemical/Petroleum/Polymer) Examination, 2011
CHEMICAL PROCESS CALCULATIONS
(2008 Course)
Time : 3 Hours Max. Marks : 100
Instructions : 1) Attempt Q. 1 or 2, Q. 3 or 4, Q. 5 or 6, Q. 7 or 8,
Q. 9 or 10, Q. 11 or 12.
2) Figures to the right indicate full marks.
3) Use of electronic calculators, steam table is allowed.
4) Draw neat sketch wherever necessary.
SECTION – I
1. a) A gas has the following composition in mole basis CO2 = 10.5%; CO = 0.2%;
O2 = 8.6% and N2 = 80.7%. Calculate its weight percentage; volume occupied
by 0.5 kg gas at 30°C and 760 mm Hg; density of gas kg/m3
and specific
gravity of the gas mixture. 6
b) The flow rate of water through a pipe is reported as 20 cubic feet per minute.
Taking density of water as 1 g/cm3
. Calculate the mass flow rate in kg/s. 6
c) Estimate the molar volume of CO2
at 600 K and 110 bar using a) ideal
gas law and b) the Van der waals equation. Van der waal constants are
0.364 N m4
/mol2
and 4.267 * 10–5 m3
/mol. 6
OR
2. a) Calculate the weight of NaCl that should be placed in a 2 litre volumetric flask
to prepare a solution of 1.4 molality. Density of this solution is 1.08 g/cc. 6
b) A gas is piped from the well at 300 K and 400 kPa. The gas is found to
contain 83% methane, 14.5% ethane and the rest nitrogen in mole basis.
Calculate :
a) the partial pressure of nitrogen
b) the pure component volume of ethane in 8 m3 of the gas
c) density at standard conditions in kg/m3
d) composition in weight percentage. 6
c) Explain the role of material and energy balance in process industry. Give
proper technical justification. 6
3. a) State various unit operations in process industry. Give the overall and component
balance for any two unit operations. 8
b) An evaporator is fed continuously with 1000 kg/hr of a solution containing
15% NaOH, 15% NaCl and 70% water by weight. During the evaporation,
water is boiled off and NaCl precipitates as crystals and removed from the
remaining liquor. The concentrated liquor leaving the evaporator contains 60%
NaOH, 2% NaCl and 38% water. 8
Calculate :
a) kg of water evaporated per hour
b) kg of salt precipitated per hour and
c) kg of concentrated liquor produced per hour.
OR
4. a) A gas containing 4% NH3
, 26% N2
and the rest H2
is flowing in a pipe. To
measure the flow rate an ammonia rich gas containing 86% NH3
, 13% H2
, and
1% N2
is sent at a rate of 100 cc/min. the concentration of NH3
in the down
stream is 8%. Find the flow rate of gas inlet. 6
b) Explain Bypass, Recycle and Purging operations with the help of block
diagrams and define the terms associated with it. 10
5. a) Define the following : Limiting reactant, Excess reactant, Percentage conversion,
Yield. Give example of each. 8
b) In manufacturing of chlorine, feed containing HCl gas and air are fed to
oxidizer. The product gas leaving the oxidizer are found to contain 13.2%
HCl, 6.3% O2
, 42.9% N2
, 30% Cl2
and 7.6% H2O (by volume). Calculate
percentage excess of air used, composition in weight of gases entering the
oxidizer and degree of completion of oxidation. 8
OR
6. a) The gaseous reaction A 2B + C takes place isothermally in a constant pressure
reactor. Starting with a mixture of 75% A and 25% inerts (by volume), in a
specified time the volume doubles. Calculate the conversion achieved. 8
b) In an oil quench process to manufacture acetylene pure oxygen and
pure methane are fed to the burner. Cracked gas from the burner has the
following composition : H2
: 56.5%; CH4
: 5.2%; C2H4
: 0.3%; C2H2 : 7.5%,
C3H6 : 0.5%, CO : 25.8%, CO2 : 4.0%, O2 : 0.2% (on dry basis). For
100 kmol of cracked gas calculate : 8
1) Methane and Oxygen requirement
2) Production of water
3) Conversion of methane and
4) Yield of Acetylene.
SECTION – II
7. Write short notes on : 18
• Bubble points and dew points of ideal mixtures
• Equation of states
• Flash calculations.
OR
8. a) Define Raoult’s Law and Henry’s Law. Calculate the total pressure
and composition of the vapors in contact with the solution of benzene (35%),
Toluene (40%) and Xylene (25%), by weight at 100°C. Vapor
pressure at 100°C are as follows : Benzene : 1340 mm Hg; Toluene : 560 mm Hg;
Xylene : 210 mm Hg. 10
b) What is Clapeyron equation and give its applications. 4
c) Give the procedure of estimate dew point pressure of an ideal solution. 4
9. a) Explain the treatment required to solve conservation of mass and energy
problems with respect to the steady and unsteady state process and batch
and continuous processes. 8
b) A square tank 6 m on a side and 9 m high is filled to the brine with water. Find
the time required for it to empty through a drain at bottom of 7 cm2
area. 8
OR
10. a) The molal heat capacity of CO is given by Cp = 26.586 + 7.582 * 10–3
T – 1.12 * 10–6T2
where Cp is in kJ/kmol K and T is in K. a) Calculate the mean
molal heat capacity in the temperature range of 500 – 1000 K b) CO enters a
heat exchanger at a rate of 500 cubic meters per hour at STP. Calculate the
heat to be supplied to the gas to raise its temperature from 500 to 1000 K. 8
b) Define with expressions : 8
a) Absolute saturation humidity b) Percent humidity
c) Humid heat d) Wet bulb temperature
11. a) Write a short note on enthalpy changes accompanying chemical reactions. 8
b) In a commercial process, chlorine is manufactured by burning hydrogen
chloride gas using air. For good conversion air is used in 35% excess of that
theoretically required. Assume that the oxidation is 80% complete and the dry
air and hydrogen chloride gas enter the burner at 298.15. Calculate
a) the composition of dry gases leaving the burner and the adiabatic reaction
temperature of the product gas stream. 8
OR
12. Write a short note on any two : 16
1) Thermo chemistry of mixing processes
2) Effect of temperature on heat of reaction
3) Significance of Adiabatic Flame temperature determination.
–––––––––––––––––
S.E. (Petrochemical/Petroleum/Polymer) Examination, 2011
CHEMICAL PROCESS CALCULATIONS
(2008 Course)
Time : 3 Hours Max. Marks : 100
Instructions : 1) Attempt Q. 1 or 2, Q. 3 or 4, Q. 5 or 6, Q. 7 or 8,
Q. 9 or 10, Q. 11 or 12.
2) Figures to the right indicate full marks.
3) Use of electronic calculators, steam table is allowed.
4) Draw neat sketch wherever necessary.
SECTION – I
1. a) A gas has the following composition in mole basis CO2 = 10.5%; CO = 0.2%;
O2 = 8.6% and N2 = 80.7%. Calculate its weight percentage; volume occupied
by 0.5 kg gas at 30°C and 760 mm Hg; density of gas kg/m3
and specific
gravity of the gas mixture. 6
b) The flow rate of water through a pipe is reported as 20 cubic feet per minute.
Taking density of water as 1 g/cm3
. Calculate the mass flow rate in kg/s. 6
c) Estimate the molar volume of CO2
at 600 K and 110 bar using a) ideal
gas law and b) the Van der waals equation. Van der waal constants are
0.364 N m4
/mol2
and 4.267 * 10–5 m3
/mol. 6
OR
2. a) Calculate the weight of NaCl that should be placed in a 2 litre volumetric flask
to prepare a solution of 1.4 molality. Density of this solution is 1.08 g/cc. 6
b) A gas is piped from the well at 300 K and 400 kPa. The gas is found to
contain 83% methane, 14.5% ethane and the rest nitrogen in mole basis.
Calculate :
a) the partial pressure of nitrogen
b) the pure component volume of ethane in 8 m3 of the gas
c) density at standard conditions in kg/m3
d) composition in weight percentage. 6
c) Explain the role of material and energy balance in process industry. Give
proper technical justification. 6
3. a) State various unit operations in process industry. Give the overall and component
balance for any two unit operations. 8
b) An evaporator is fed continuously with 1000 kg/hr of a solution containing
15% NaOH, 15% NaCl and 70% water by weight. During the evaporation,
water is boiled off and NaCl precipitates as crystals and removed from the
remaining liquor. The concentrated liquor leaving the evaporator contains 60%
NaOH, 2% NaCl and 38% water. 8
Calculate :
a) kg of water evaporated per hour
b) kg of salt precipitated per hour and
c) kg of concentrated liquor produced per hour.
OR
4. a) A gas containing 4% NH3
, 26% N2
and the rest H2
is flowing in a pipe. To
measure the flow rate an ammonia rich gas containing 86% NH3
, 13% H2
, and
1% N2
is sent at a rate of 100 cc/min. the concentration of NH3
in the down
stream is 8%. Find the flow rate of gas inlet. 6
b) Explain Bypass, Recycle and Purging operations with the help of block
diagrams and define the terms associated with it. 10
5. a) Define the following : Limiting reactant, Excess reactant, Percentage conversion,
Yield. Give example of each. 8
b) In manufacturing of chlorine, feed containing HCl gas and air are fed to
oxidizer. The product gas leaving the oxidizer are found to contain 13.2%
HCl, 6.3% O2
, 42.9% N2
, 30% Cl2
and 7.6% H2O (by volume). Calculate
percentage excess of air used, composition in weight of gases entering the
oxidizer and degree of completion of oxidation. 8
OR
6. a) The gaseous reaction A 2B + C takes place isothermally in a constant pressure
reactor. Starting with a mixture of 75% A and 25% inerts (by volume), in a
specified time the volume doubles. Calculate the conversion achieved. 8
b) In an oil quench process to manufacture acetylene pure oxygen and
pure methane are fed to the burner. Cracked gas from the burner has the
following composition : H2
: 56.5%; CH4
: 5.2%; C2H4
: 0.3%; C2H2 : 7.5%,
C3H6 : 0.5%, CO : 25.8%, CO2 : 4.0%, O2 : 0.2% (on dry basis). For
100 kmol of cracked gas calculate : 8
1) Methane and Oxygen requirement
2) Production of water
3) Conversion of methane and
4) Yield of Acetylene.
SECTION – II
7. Write short notes on : 18
• Bubble points and dew points of ideal mixtures
• Equation of states
• Flash calculations.
OR
8. a) Define Raoult’s Law and Henry’s Law. Calculate the total pressure
and composition of the vapors in contact with the solution of benzene (35%),
Toluene (40%) and Xylene (25%), by weight at 100°C. Vapor
pressure at 100°C are as follows : Benzene : 1340 mm Hg; Toluene : 560 mm Hg;
Xylene : 210 mm Hg. 10
b) What is Clapeyron equation and give its applications. 4
c) Give the procedure of estimate dew point pressure of an ideal solution. 4
9. a) Explain the treatment required to solve conservation of mass and energy
problems with respect to the steady and unsteady state process and batch
and continuous processes. 8
b) A square tank 6 m on a side and 9 m high is filled to the brine with water. Find
the time required for it to empty through a drain at bottom of 7 cm2
area. 8
OR
10. a) The molal heat capacity of CO is given by Cp = 26.586 + 7.582 * 10–3
T – 1.12 * 10–6T2
where Cp is in kJ/kmol K and T is in K. a) Calculate the mean
molal heat capacity in the temperature range of 500 – 1000 K b) CO enters a
heat exchanger at a rate of 500 cubic meters per hour at STP. Calculate the
heat to be supplied to the gas to raise its temperature from 500 to 1000 K. 8
b) Define with expressions : 8
a) Absolute saturation humidity b) Percent humidity
c) Humid heat d) Wet bulb temperature
11. a) Write a short note on enthalpy changes accompanying chemical reactions. 8
b) In a commercial process, chlorine is manufactured by burning hydrogen
chloride gas using air. For good conversion air is used in 35% excess of that
theoretically required. Assume that the oxidation is 80% complete and the dry
air and hydrogen chloride gas enter the burner at 298.15. Calculate
a) the composition of dry gases leaving the burner and the adiabatic reaction
temperature of the product gas stream. 8
OR
12. Write a short note on any two : 16
1) Thermo chemistry of mixing processes
2) Effect of temperature on heat of reaction
3) Significance of Adiabatic Flame temperature determination.
–––––––––––––––––
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