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 The
operations carried out in the chemical
process industry involving physical changes in
the materials handled or in the system under
consideration are called Unit operations.
 The
unit process involves a chemical change
or sometimes it referred to as chemical
changes along with physical change leading
to the synthesis of various useful product.
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
Boiler
Reactor
Furnace
Heater
Cooler
Vaporizer
Heat exchanger
Cooling tower
Filtration unit
Sedimentation unit
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 Pump
 Compressor
 Crusher
 Sieving
equipment
 Mechanical cleaning unit
 Gas liquefaction unit
 Refrigerator
 Absorber
 Stripper
 Distillation
 Extractor
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The Block Flow Diagram has the purpose of
illustrating the logical flow of the processing
phases of the product, highlighting the
processing sequence, their concatenations and
the types of treatment plant: each block
represents a treatment unit of the process plant.
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The Process Flow Diagram examines the single
unit or the plant itself, and it represents the
main equipment, the connections between them
(pipes), highlights the main tools (equipment,
instruments, and valves), and the essential
settings for a correct operation and a correct
management of the plant itself, as the following
nominal operate conditions:
• Flow
• Pressure
• Temperature
• Chemical composition
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The Process & Instrumentation Diagram supply
all the information necessary for the
construction and operability of the plant.
• Data and characteristics of the equipment
• Numbering and classification of pipes
• Instrumentation in the control room
• Instrumentation and valves in the field
• Construction and installation notes
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There are two reactants, one is vaporized and fed to reactor at 10 bar and
300 C. While other is compressed and heated to 10 bar and 300 C. The
reaction is exothermic and temperature is maintained through coolant oil in
jacketed reactor. The exit stream is cooled down and then sent to two phase
separator. The vapor stream is scrubbed and sent to environment. The liquid
stream is sent to absorber and product is obtained. The solvent is regenerated
in stripper.
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Toluene and hydrogen are used as feed stocks for the production of benzene.
The toluene and hydrogen are sent to a reactor, and the effluent is sent to a
gas separator where the non-condensable gases are discharged from the
system. The bottoms of the separator provides a liquid feed to a still where
the lighter benzene gas is collected as the distillate and the bottom toluene
draw is recycled back into the reactor.
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Crude oil is fed to a pre-flash separator (vertical vessel) operating at 455F
and 70 psia. The separator will separate vapors from liquids. The vapor
coming out of the separator is sent to mixer. On the other hand, the liquid
leaving the separator will be fed to a fired heater to heat it to (700F) before
being sent to the same mixer where it will mix with the vapors. The
combined liquid-vapor stream is then fed to a distillation column where it
will be separated into different products such as LPG, Gasoline, Kerosene
Diesel.
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In this process, the hydrocarbon feedstock is mixed with hydrogen then
preheated in a fired heater to 320°C. After the preheating, the feedstock is
charged through a fixed- bed catalytic reactor. In the reactor, the sulfur and
nitrogen compounds in the feedstock are converted into H2S and NH3. The
reaction products along with hydrogen, H2S and NH3 leave the reactor and
are cooled using a heat exchanger. After cooling to a low temperature, the
cooled stream enters a high- pressure separator (horizontal vessel). The
hydrogen-rich gas leaving from the top of the high-pressure separator is
recycled to combine with the feedstock. The remaining stream will enter to a
fractionator where the off-guses (H2S and NH3) are separated and removed
from the top of the tower. Meanwhile the desulfurized product will exit from
the bottom of the column.
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