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Name
Reg No

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY
07 THRISSUR CLUSTER
THIRD SEMESTER M.TECH. DEGREE EXAMINATION DEC 2017
Department: Chemical Engineering
Specialisation: Process Control
07CH 7111 Process Safety Engineering
Time 3 hours Max.Marks: 60
Answer all six questions. Part of each question is compulsory.
Answer either part or part of each question
Q.no. Module 1 Marks
1a Define reportable accident and where do you report the accident from a
factory.
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Answer b or c
b What are the LFL and UFL of a gas mixture composed of 0.8% hexane,
methane and 0.5% ethylene by volume.
Components
Volume LFL UFL
Hexane 0.8 1.2 7.5
methane 2 5.3 15
Ethylene 0.5 3.1 32
5
c Particular lubricating oil has an AIT of 400C. Compute the compression ratio
required to raise the temp of air to the AIT of this oil. Assume an initial air
compressor of 25C and 1atm.
5
Q.no. Module 2 Marks
2a Develop the empirical equation for calculation of Fire index, internal explosion
index and Aerial explosion index.
4
Answer b or c
b An ammonia storage tank having a capacity of 10000 tonns situated at Eloor
having a GPHtot of 1.5, SPHtot of 3.6. Calculate the Dow Fire Explosive index
and toxicity index. Data:
Material factor of Ammonia 6
NFPA index figure
Toxicity factor 250
MAC value 20ppm
Penalty 75
5
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c Your plant is considering the installation of a new rail car tank unloading
facility. The facility will unload 25000gal tank cars containing either pure
butadiene or cyclohexane. The unloading system equipped with an emergency
shutdown system with remotely operated block valves. The unloading
operation will be down by computer control. The rail cars are inerted with N2 to
a pre of 40 psig, and the rail car relief system has a set pre of 75 psig.
Combustible gas detectors will be located at the unloading station. A deluge
system will be installed at the unloading site with excellent water supply. A
diking system will surround three sides of the facility with any spills directed to
a covered impounding area.
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Q.no. Module 3 Marks
3a Differentiate between Fault tree analysis and Event tree analysis with suitable
example.
4
Answer b or c
b Consider a plant in which chemicals A and B react to form a product C.
Suppose that the chemistry of the process is such that the concentration of
raw material B must never exceed that of otherwise an explosion may
occur. Carry out HAZOP study for the pipeline extending from the suction side
of the pump which delivers raw material A to where it enters the reaction
vessel. (Take suitable assumptions)
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c State and explain the OR gate and AND gate rule used for resolving all the
gates into basic events with suitable example.
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Q.no. Module 4 Marks
4a Enumerate the major steps involved in Consequence analysis. Explain. 4
Answer b or c
b At 1 pm the plant operator notices a drop in pressure in a pipe line transporting
benzene. The pressure is immediately restored to 100 psig. At 2.30 pm, a 1/4
inch diameter leak is found in the pipe line and immediately repaired. Estimate
the total amount of benzene spilled. The specific gravity of benzene is 0.8794.
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c Differentiate between the puff model and plume model of dispersion of gases. 5
Q.no. Module 5 Marks
5a Differentiate between onsite and offsite emergency plan .Write the significance
of Mock drill.
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Answer b or c
b What are the different methods to represent the Individual risk and societal
risk? Explain.
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c
Describe the salient features of Probit function. Determine the likely
percentage of fatalities from a 20 minute exposure of 400 ppm chlorine.
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Q.no. Module 6 Marks
6a Differentiate between SLIM and THERP. 5
Answer b or c
b With suitable example explain the human error assessment and reduction
technique (HEART).
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c With neat diagram explain the different layers of protection implemented to
enhance the process safety.
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