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Explain the third law of thermodynamics. The third law states that 'As a system approaches absolute zero, the entropy of the system approaches a minimum value'.
What is entropy? Entropy is a measure of disorderliness. It explains the system's closeness to equilibrium.
What is Gibbs free energy? It is the available energy or the greatest amount of mechanical work done by a system at constant temperature and pressure.
At what temperature does water have maximum density? At 4 deg C the density of water is 1000 kg/cu.m.
What is an isochoric process? It is a thermodynamic process at constant volume. Also called isovolumetric process
What is a CSTR and what are its basic assumptions? Continuous Stirred tank Reactor. Assumptions are steady state, constant density, constant temperature, one irreversible first-order reaction.
List the advantages and disadvantages of a PFR. Advantages: Continuous operation, high conversion rate, less cost for operation. Disadvantages: temperature gradients, high maintenance cost.
Explain the functioning of a three-way catalytic converter. Carbon monoxide oxidation, Nitrogen oxide reduction, uncombusted hydrocarbon oxidation.
Explain global warming from a common man's and an engineer's perspective. In a common man's perspective, the increase in world temperatures is global warming. In an engineer's perspective, it is the average temperature increase in the surface temperature of the earth, mainly due to increased concentration of greenhouse gases. The greenhouse gases capture the heat radiated by the earth, inside the atmosphere, enabling the increase in temperature.
What is carbon sequestration? A technique for capturing carbon dioxide for a long term in order to reduce its effects on global warming.
What are the greenhouse gases in earth's atmosphere? Water vapor, carbon dioxide, ozone, methane, nitrous oxide and CFC.
Define octane number. It is the resistance to detonation of a fuel in a spark ignition engine compared to the isooctane-n-heptane mixture.
Explain the working of a spray condenser A spray condenser is used for the condensation of humid water vapor by direct contact with water. The inlet water is at a temperature less than the dew point of air in the chamber.
How does a cyclone separator work? It works as gas-solid separation equipment using vortex formation.
Define viscosity. Viscosity is a measure of a fluid's resistance to shear stress.
What is critical radius of insulation? The critical radius of insulation is the thickness of an insulation that does not affect the convection resistance. It is the ratio of the thermal conductivity of the insulator to the convection heat transfer coefficient.
What is a black body? An ideal object that absorbs all electromagnetic radiations.
Explain the designing of distillation column
o narender sharma
o Chemical Engineering Interview Questions
pavan satisho Sep 8th, 2015
If RV>1, you will see that large variation in vle curves, it shows that more volatile component going to vapour phase and less volatile component coming to liquid, this is our theme too. If RV=1, mo...
Rupesh mandloio Jun 30th, 2014
Design of distillation column job is very difficult to other work, in the designing of distillation column first find out vapour velocity ( vapour velocity V=1.2/(density of mixture)^0.5 then find molecular wt of gas and then find column dia. by D=0.0164(V)^0.5(Mol.wt of gas/molar density)^0.25
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DEC152006
11:17 PM
7366
Views
6
Ans
How to seperate water from benzene
o tanvir
o Chemical Engineering Interview Questions
amit kumar panigrahio Sep 4th, 2015
When water is mixed with benzene it creates a layer. Water having more density as compare to benzene so its falls to lower part and benzene in upper part. In industries we use "Gravity separator", "U-seal funnel separator".
Galalo Aug 5th, 2015
Distillation
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JUN132015
11:13 AM
1377
Views
3
Ans
Calculate Heating of Natural Gas
o satyaprasad
o Chemical Engineering Interview Questions
How can we calculate heating of natural gas?
amit kumar panigrahio Sep 4th, 2015
We are using gas chromatogrpahy for calculating the carorific value of a combution gas
Niharo Sep 3rd, 2015
By thermocouple, pyrometer, We can measure and calculate the heat of Natural gas..Â
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NOV242014
12:04 PM
1583
Views
1
Ans
Convert the units
o Shaip ahmed
o Chemical Engineering Interview Questions
In the American Engineering system of units, the viscosity can have units of (lbf)(hr)/ft^2, while in the SI system, the units
are (g)/(cm)(s). Convert a viscosity of 20.0 (g)/(m)(s) to the given American Engineering units?
paul ericsono Jul 22nd, 2015
1g/cm.s = 0.002 lbf.s/ft^2so, 1g/m.s = 100g/cm.sso, 20g/ms=2000g/cm.snow,2000*0.002= 4lbf.s/ft^2to convert into lbf.hr/ft^2,. 1 sec =0.00027 hr. so multiply by 0.00027so, 4*0.00027=0.00108 lbf.hr/ft^2.
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JUN062007
10:27 AM
36057
Views
24
Ans
What is the difference between unit operation and unit process
o nageswararao are
o Chemical Engineering Interview Questions
paul ericsono Jul 22nd, 2015
The core of chemical engineering is all about unit operations and unit process. All chemical industries will do both process and operations. where operation is a physical change and process is a chemi...
Abrarkhano Jul 17th, 2015
Unit Process - Chemical change onlyUnit Operation - Physical change only
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MAR012015
05:56 PM
2026
Views
2
Ans
Furnace
o ashwin
o Chemical Engineering Interview Questions
As we know steel making is done in a furnace at very high temperatures, but how is that temperature maintained in a
furnace on continuous basis ??
paul ericsono Jul 22nd, 2015
We can control the fuel rate to the furnace.for this we can use air-ratio control system where your process instrumentation control comes in to play. refer( air ratio control system)
Niharo Jun 2nd, 2015
It is maintained by flow rate of natural gas or any fuel that is used for furnace... and this high temp is measured by thermocouple and from thermocouple we change the rate..
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FEB162008
11:20 PM
19019
Views
21
Ans
Difference between Distillation and Fractionation?
o nalamnaresh
o Chemical Engineering Interview Questions
Ravipaulo Jul 9th, 2015
Distillation: Technique of preferential separation of more volatile components from less volatile components by partial vaporization followed by condensation. Fractionation: Its a special type of Dis...
Vairamuthuo May 25th, 2015
Fractionation is one of the method of distillation process. Separation of a particular liquid from the liquid mixture based on their corresponding boiling point is commonly known as distillation. Frac...
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MAY302011
11:05 AM
11481
Views
20
Ans
Heat exchangers
o abhilashchakravarty
o Chemical Engineering Interview Questions
What is the basis of choosing the shell side and tube side fluid?
bhargavo Jun 25th, 2015
For choosing a fluid in shell or tube side, we have to consider mainly two things. 1. Corrosiveness : More corrosive fluid will be in tube side as we can replace the tube bundle. 2. Operating Pressu...
ajendra manio May 3rd, 2015
If more viscous liquid send to shell side then baffle will help to create turbulance .However hot fluid are less voscous
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JUN202015
02:41 AM
741
Views
0
Ans
Coating in Cement Mill Fan and Separator
o niladri
o Chemical Engineering Interview Questions
Why there is coating in cement mill fan and separator ?
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FEB102010
07:28 AM
5078
Views
6
Ans
Unit Process and Unit Operations
o chemienger
o Chemical Engineering Interview Questions
What is Unit Process and Unit Operations? How they are different from one another?
suraj kumaro Jun 19th, 2015
Unit operation is a physical changes only but unit process is a chemical changes.
kiran kumaro Sep 3rd, 2014
Only physical change unit operation physical and chemical change unit process
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FEB162015
01:18 PM
2327
Views
1
Ans
Pressure Purging
o Mbahaa
o Chemical Engineering Interview Questions
Hi
please i need some help here
i want to ask a few questions about pressure purge method used for inert a vessel:
1-Does The Material/ Gas inside the vessel affect the purge technique ?
2-What about an inlet natural gas filter ( with elements ), does the element affects the purge ?
3- why in some books when implement the equation to calculate number of purge cycle-...
Josho Mar 18th, 2015
Typically getting below 2% oxygen is standard for preventing explosive conditions depending on the process (O2 sensitive catalyst, O2 impurity intolerable). Â Three pressure ups to 50 psi with N2 and dumps or two pressure ups to 100 psi and dumps are typically performed.Â
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OCT262011
04:30 PM
5691
Views
2
Ans
What is pseudo pressure ?
o abbas
o Chemical Engineering Interview Questions
shah siddharth jo Feb 24th, 2015
Pseudo pressure is the mathematical expresion accounts for variable compressibility and viscosity of gas with respect to pressure
suji
o Mar 19th, 2012
In regard to pressure the mathematical pressure function for the variable viscosity and compressibility of gas is Pseudo-pressure or real gas potential. Itâs the changes that occur in gas properties with pressure.��
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FEB092015
07:32 AM
1615
Views
1
Ans
Composite and alloy
o shatha92
o Chemical Engineering Interview Questions
What is the difference between composite and alloy metals ?
akhlaq mohsino Feb 19th, 2015
Composite is compound more than two metal or non metal while alloy is the compound of metal only.regard
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FEB052015
04:30 AM
1034
Views
0
Ans
Domestic refrigeration
o Jan Dreyer
o Chemical Engineering Interview Questions
I need to work out all on my own what the length of the capillary tube should be and what the id of it must be for different
types of domestic refrigerant and compressor sises
We use R22 ;R134A ;and R600 refrigerant gasses and 1/6 ;1/5 and 1/4 hp comresors . The fridges all differ in size
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APR042012
06:25 AM
4840
Views
4
Ans
What is valency?
o Kishan Busa
o Chemical Engineering Interview Questions
jitendrao Jan 20th, 2015
It is a tendency of element to gain or remove electron to get stable electron configuration.
Abdelgawado Mar 31st, 2014
A property of atoms or groups, equal to the number of atoms of hydrogen that the atom or group could combine with or displace in forming compounds
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NOV162012
05:20 AM
2833
Views
1
Ans
How to conduct the VLE experiment at atmospheric pressure?
o Emma89
o Chemical Engineering Interview Questions
Anyone can help me to explain how to conduct the VLE experiment for propane and heptane composition? it is possible to
use normal stirring extraction method for the experiment? And how much amount of heptane and propane that should i use
if i choose the temperature range of 0-60 degree Celsius?
Ramani Ashisho Jan 16th, 2015
If all component are from the same group and operating pressure for distillation is atmospheric then vapor-liquid equilibrium can be assumed as ideal vapor-liquid equilibrium. using Raoults law obtain VLE data.
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NOV132011
12:26 PM
7357
Views
9
Ans
Why it takes more time to distill out water than toluene?
o satya
o Chemical Engineering Interview Questions
Vipin Agrawalo Nov 28th, 2014
And if boiling temperature is high then vapor pressure is also high for a component. Both things (boiling point and vapor pressure) are correlated by antoins equation.
rajeevo Jul 26th, 2012
In case of azeotrope only alternative is through azeotropic distillation ... extractive distillation s used when relative volatility is close to 1 and no of tray reqd r high
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MAR122009
01:04 PM
6820
Views
8
Ans
Law of Thermodynamics
o azeemravian
o Chemical Engineering Interview Questions
What is 3rd Law of Thermodynamics?
Habib Khano Nov 26th, 2014
When system approaches ABSOLUTE ZERO, Its ENTROPY will be minimum.
jitendra patilo Feb 15th, 2014
Value of absolute entropy
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FEB252011
01:12 AM
6031
Views
7
Ans
Can Bernaulli's theorem be applied on gases?
o abhi11092451
o Chemical Engineering Interview Questions
As Bernaulli's theorem is applied on fluids, so can we apply it on gases also?
Vipin Agrawalo Nov 21st, 2014
I think the answer is No.
Since gases are always compressible and the main assumption is the bernauli equation is that flow should be in-compressible, So Bernauli cant be applied on gases but navier stokes is always applicable for any type of fluids.
Vipin Agrawalo Nov 21st, 2014
Since gases are always compressible and the main assumption is the Bernoulli equation is that flow should be in-compressible, So Bernoulli cant be applied on gases but naiver stokes is always applicable for any type of fluids.
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What common name for
o kawin
o Chemical Engineering Interview Questions
1) 2-methyl-3-pentanol
2) 3-phenyl-2-butanol
3) cis-1,4-cyclohexadiol
1. What is the Driving force for fluid flow? Answer click here
2. Why distillation? Why not adsorption or leaching ? Answer click here3. Pressure drop equation for horizontal pipe line in laminar flow condition? Answer
4. When reflux ratio to the column is minimum and zero, what are the requirements in column ? Answer 5. Define Intensive and extensive properties, give examples for them ?Answer
6. What is jigging and where it is used ? Answer
7. Pressure drop equation for Inclined pipe line in laminar flow condition?(Inclination by an angle ) Answer8. What is meant by differential distillation? Ans: Click Here 9. What is dew point ? Ans: Click Here10. What is first order system or which system is called a first order system ?Ans: Click Here
11. Transfer function for PID controller ? Ans : Click Here 12. U-tube manometer is first order system or second order system? Ans : Click Here13. Laws of crushing ? Kick's law, Rittingers law, Bond's law ? Ans: Click Here14. Draw the inclined manometer diagram? Answer click here15. Write the pressure drop equation for inclined manometer? Answer16. Use of inclined manometer? Answer click here17. What are differences between pipe and tube? Answer click here18. Types of pumps? Answer19. Draw the centrifugal pump diagram and show the impeller and fluid flow direction? Answer click here20. What are main uses of volute in a centrifugal pump? Answer click here21. Definition of NPSH? Answer click here22. Why cavitation will occur in Centrifugal Pumps?. why not in displacement pumps? Answer23. NPSH calculation for suction lift? Answer24. NPSH calculation for suction Head? Answer25. Determine whether cavitation will occur in the following condition or not? Water at 70 C ,Datum height 5 m (for suction lift condition), & tank is exposed to atm. Answer26. Write force bance on rotameter float and write advantages and disadvantages? Answer27. Units of viscosity? Answer click here28. Difference between Kinematic viscosity and dynamic viscosity? Answer29. Write the forces acting on particle falling in fluid? Answer30. How to write particle Nre? Answer31. How to calculate particle diameter? Answer32. What is minimum fluidization velocity? Answer33. How to calculate minimum fluidization velocity? Answer34. What is the Driving force for Mass Transfer? Answer click here35. What is the Difference between partial condenser and total condenser? Answer36. If column Delta P decreases what happens to the purity?(In this case it is assumed that bottom pressure is constant) Answer
37. What is the Driving force for Evaporation? Answer38. In which column Delta P is high ?(Packed column or tray column) Answer39. When we will choose packed column? Answer40. What is minimum reflux ratio? Answer41. How to calculate minimum reflux ratio? Answer42. Draw the x-y diagram? Answer43. Explain Me cab thiele method? Answer44. Why reaction will takes place? Answer click here45. C + O2 ---------- CO2 when this reaction is feasible? Answer click here46. What are the differences between MFR and PFR? Answer47. Write the performance equations for MFR, PFR and Batch Reactors? Answer48. A ---k1--- R---k2---- S for the above reaction draw the selectivity diagram when k1 greater than k2 and k1 less than k2? Answer49. How to find out the order of the reaction? Answer50. A-------R is a nth order reaction. For above reaction how to select a reactor type? and which reactor will give more conversion for same volume of the reactor? Answer51. How to calculate the reactor volume using graphical method for MFR and PFR? Answer52. What is the driving force for Heat Transfer? Answer click here53. Classification of heat exchangers? Answer54. Draw 1-1 Heat Exchanger? Answer click here55. Draw 1-2 Heat Exchanger? Answer click here56. Which Heat Exchanger is efficient 1-1 or 1-2? and Why? Answer57. In a 1-1 Heat exchanger shell side fluid is steam at 100 C and it is leaving as water at 100C which flow pattern will give more Heat transfer? and why? Answer58. How to calculate U(Overall heat transfer coefficient)? Answer59. Draw the temperature profiles for 1-1 heat exchanger in parallel and counter flow conditions? Answer click here 60. Why Don't we use odd number of tube passes in Shell and Tube Heat Exchanger? Answer click here61. What is the difference between DCS and PLC? Answer click here 50. For the given problem below find the rate of change of 'h' w.r.t 't' using appropriate assumptions? Answer click here
FREQUENTLY ASKED QUESTIONS ON COMPRESSORS:
Q: Where does the head gets developed in a centrifugal compressors?
Answer
Q: What is pressure ratio of a compressor:
Answer
Q: What sort of bearings are used for high speed compressors?
Answer
Q: In what services centrifugal compressors are used? Answer
Answer
Q: How reliable are centrifugal compressors?
Answer
Q: In what services barrel compressors are used?
Answer
Q: What are side-stream compressors?
Answer
Q: How the compressors are sealed?
Answer
Q: What type of seals are used for air compressor?
Answer
Q: Whether online cleaning is used for compressors?
Answer
Q: Can centrifugal compressors tolerate high molecular weight fluctuations?
Answer
Q: What is surging?
Answer
Q: How is surging harmful?
Answer
Q: What type of seals are more reliable in hazardous services?
Answer
Q: What should be the seal configurations in hydrocarbon services?
Answer
Q: How does on identify seal leakage?
Answer
Q: What are compressor protections?
Answer
Q: Are liquids in the process detrimental to compressors?
Answer
Q: What is turndown?
Answer
FREQUENTLY ASKED QUESTIONS ON PUMPS:
1.Does excessive amount of air at the pump suction cause cavitation? Answer
2.Can a gear pump "lift" liquid? What is dry lift? Answer3.What determines number of stages of the progressing cavity pumps? Answer
4. Is it true that if centrifugal pump runs in reverse, it will generate zero head?Answer
5. "How Does Pump Suction Limit the Flow?" Answer
6. Please discuss how pumping water differs from pumping 40% Propylene Glycol. Does the impeller have to change trim to produce the same flow and head with a more viscous solution? Answer
7. What is the effect of the degree of saturation of dissolved gasses on NPSH? Compare 100 deg F deaerated water in a tank with a bladder pressured to 10 psig with a tank without a bladder for the same temperature and
pressure, with the pressure provided by, say, a nitrogen bottle causing the water to be saturated with nitrogen. Answer
8. Explain about
1)backward curved blades
2)forward curved blades
3)comparison of above
4)which is more advantageous and why? Answer
TECHNICAL INTERVIEW QUESTIONS:Question:01Which Steam contains greater amount of Latent Heat(1) 10 bar(2) 30 barQuestion:02Efficiency of Cooling Tower?Question :03Can we replace Expansion valve with turbine in refrigeration cycle?Question :04Pump works on adiabatic or isothermal principle?Question:05What is flushing in pumps?Question:06Why Bubble and dew point are same for water?Question:07What are affinity laws for pumps?Question: 08Mesh Number?Question :09Why a compressor is needed in brayton cycle?Question:10In Cation resin why Ca+2 is deposited first in the bed and Na+1 at the bottom ?Question :11What is difference between average temperature and LMTD?Question :12Performance curves for pumps?Differentiate between P & ID and PFD?Question:13Equivalent length,schedule number, & BWG?Question:14What is approach in cooling tower and how is it affected by wet bulb temperature?Question:15Difference between fan,blower and compressor?Question:16Differentiate between cavitation & surging?Question:17
Working principle of pyrometer,thermocouple,RTD & thermistor?Question:18Types of turbines,compressors and pumps?Question:19Can pump and turbine be used in place of compressor?Question:20what is draft,static pressure,pressure head,suction head,NPSH?Question:21How would you reduce NPSH?Question:22Write bernoulli equation?Question No:23Write about 10 parts of shell & tube heat exchanger(asked in FFC)?design of shell n tube exchanger?fluid allocation?Question No:24Differentiate between condenser & heat exchanger?evaporator & cooling tower?Question:25Types of condensation,heat transferQuestion :26Why is inter staging cooling is provided in compressors?Question No:27What is primming of pumps?Question No:28Laws of thermodynamics?Question No:29How will you judge the flowing fluid that it is laminar or turbulent?Question No:30What is throttling?Pressure drop in globe n gate valveQuestion No:31Differentiate between gate,globe,butterfly,plug and ball valve?Question No:32What is reflux ratio in distillation column?Question No:33Foaming,channeling,weeping and flooding in column?Question No:34Types of plates?which type has more pressure drop?types of plate efficiency?Question No:35What is pinch technology?How is compressor efficiency calculated?
Note:Must revise all basics (definitions & engineering laws) you studied in engineering?Prepare your internship and final year project?