487732840-UNIT-Proses-IN-chemical-Engineering

Unit Proses
Tujuan :
1, Memahami fungsi dari unilt operasi yang umum digunakan di proses kimia
2. Menggambar flowchart dan memberikan penjelasan
3. Menuliskan semua pernyataan yang diketahui di proses

1
Divider
A splitter is used to divide the flow rate in a certain stream into
two or more streams with different flow rates In this case, the
composition of streams F1, F2, and F3 is the same since no
operation is taking place between inlet and exit streams. There
is only one independent material balance even in the case of a
multicomponent system, since all compositions are equal. Mass
flow rates F1, F2, and F3 may be different

2
The mixing process has the following characteristics: There are
two or more entering streams, and only one exit stream
resulting from the blending of the incoming streams. The
streams can be in any phase, that is, gas, liquid, or solid
Mixer
(Blender)

3
Dryer (Direct
Heating)
Drying is a mass transfer process resulting in the removal of
moisture by evaporation from a solid, semisolid, or liquid to
produce a solid state. To achieve this operation, the dryer is
supplied with a source of heat. Vapor is produced in the
process. Solvent stream leaves as a pure vapor and is free of
solids. Resulting dried products are in solid phase. Dried solids
may not be solvent free. Feed can be solid, slurry, or solution.

4
Filter
Filtration is a technique used either to remove impurities from a liquid or
to isolate a solid from a fluid. Filtration is commonly a mechanical or a
physical operation that is used for the separation of solids from fluids
(liquids or gases) by interposing a medium through which only the fluid
can pass. Filtration can also be used to separate particles that are
suspended in a fluid, where the latter can be a liquid, a gas, or a
supercritical fluid. Depending on the application, either one or both of the
components may be isolated. In the filtration process, filtrate, the exit
liquid, is free of solids. The filtrate is saturated with soluble components.
Concentration of stream 2 and the liquid remaining with the filter cake is
the same

5
Distillation
Coloumn
Distillation is a method of separating
chemical substances based on
differences in their volatilities.
Distillation usually forms part of a
larger chemical process. In the
distillation column, more volatile
components are in the distillate,
while less volatile components are in
the bottoms. Separation is
accomplished by boiling. Each tray
accomplishes a fraction of the
separation task by transferring the
more volatile species to the gas phase
and the less volatile species to the
liquid phase. Material and energy
balances can be performed on an
individual tray, the column, bottom
reboiler, or top condenser, or the
entire system.

6
Multi effect
Evaporator
The process of evaporation is used in the different branches of the
industry for food or chemicals processes, in which the concentration of the
solutions is required. Theoretically, multiple-effect evaporators allow
decreased consumption of energy for a concentration almost
proportionally equal to the number of effects (evaporators). However,
being expensive, evaporators require the reduction in the number of
effects, in order to be cost-effective. The optimal number of effects is
generally determined via calculations .The specifications of an evaporator
are similar to those of a dryer, except that both process streams (feed and
condensate) are liquids in the case of an evaporator.

7
A dehumidifier with internal cooling or heating coils is shown
below. It is a device that reduces the level of humidity in air or a
gas stream. A dehumidification process has the following
characteristics: Feed stream contains a condensable component
and a noncondensable component, and the condensate is a liquid
with the condensable component only, such as water in air .
Dehumidifikasi

8
Humidifika
si
Humidifier is a device that increases the amount of
moisture in indoor air or a stream of air. It operates by
allowing water to evaporate from a pan or a wetted
surface, or by circulating air through an air-washer
compartment that contains moisture. Humidifier
processes have the following characteristics: Feed gas is
not saturated, liquid is evaporated in the process unit,
and exit product may or may not be saturated [4]

9
Leaching and
Extraction
Leaching is the removal of materials
from solids by dissolving them. The
chemical process industries use
leaching, but the process is usually
called extraction. Leaching of toxic
materials into groundwater is a major
health concern. Extraction processes
have the following characteristics: Two
liquid solvents must be immiscible and
have different specific gravities, and at
least one component is transferred
from one solvent to the other by a
difference in solubility. The process is
often called liquid–liquid extraction. If
one of the feed streams is a solid, the
process is called leaching or liquid–
solid extraction .In leaching, the liquid
to which materials are extracted from a
carrier is not always a solvent.

10
Absorber
(Stripper)
In gas absorption, a soluble component is absorbed by contact with a liquid phase in
which the component is soluble. An absorber is often called a scrubber. This system is
used for absorbing impurities from a gas stream of certain components such as
hydrogen sulfide, carbon dioxide, and ammonia, using a suitable solvent. Absorption
processes have the following characteristics: The purpose of the unit is to have the
liquid absorb a component from the feed gas. The liquid stream flows down through
the tower due to gravity, while the gas stream is pumped upward through the tower. No
carrier gas is transferred to the liquid. Generally, no liquid solvent is transferred to the
gas stream. Desorption is the same process as gas absorption except that the component
transferred leaves the liquid phase and enters the gas phase. In general, in an absorption
tower (absorber), a gas is contacted with a liquid such that one or more components in
the gas are transferred into the liquid. A stripping tower (stripper) also involves a gas
contacting a liquid, but components are transferred from the liquid into the gas.

11
A partial condenser partly condenses a vapor stream. Partial
condensers have the following characteristics: Feed stream
contains only condensable vapor components, and exit streams
contain liquid, L, and vapor, V, which are in equilibrium.
Condensation is caused by cooling or increasing pressure .
Liquid and vapor emerging from the partial condenser are
separated using a flash separator.
Partial
Condenser and
Flash Separator
Schematic of a partial condenser followed by a flash unit

12
Flash separator splits a liquid feed into vapor- and liquid-phase
products (Figure 2.13). Flash units have the following characteristics:
The process is the same as that of a partial condenser except that the
feed is a liquid, and vaporization is caused by reducing the pressure or
by heating. Vapor and liquid streams are in equilibrium.
Flash Separator

13
Crystallizers are used in industry to achieve liquid–solid
separation. The process for a crystallizer involves a
crystallizer–filter combination so as to separate solid crystals
from a solution. Solid crystals are formed in the unit by a
change in temperature. Crystallization is capable of generating
high purity products with a relatively low energy input.
Crystallizer

14
Reactors
A chemical reactor carries out a chemical reaction that converts
molecular species in the input (whereby a species loses its identity) to
different molecular species in the output. Picture below shows a
typical reactor that has two reactant feed streams and a recycle
stream. A reactor is often named by the chemical reaction taking
place within it. A reactor is sometimes preceded by a fictitious mixer,
if the combined reactor feed is specified or must be determined.
Multiple exit streams are shown to remind you to watch for streams
that separate because of their different phases. There are various types
of reactors used in industry. The most common ones are the batch
reactor, plug flow reactor (PFR), packed bed reactor (PBR),
continuous stirred tank reactor (CSTR), and fluidized bed reactor

15
A simplified schematic of a batch reactor is shown in below. The
reactor content is loaded all at once and continuously mixed. The key
characteristics of a batch reactor are unsteady-state operation (by
definition) and spatial uniformity of concentration and temperature
(perfectly mixed); that is, the reactor is a lumped parameter system.
Batch operation is mainly used for small-scale production and is
suitable for slow reactions. A batch reactor is mainly (not exclusively)
for liquid-phase reactions with large charge-in/cleanup times.
Batch Reactor

16
The key characteristics of a PFR are steady-state operation
,variation of concentration and temperature on space, no
mixing along the reactor but complete mixing in the radial
direction of the reactor; PBR is suitable for fast reactions and
mainly used for gas-phase reactions with difficult temperature
control, and no moving parts .
PFRs dan PBRs

17
CSTR and
Fluidized Bed
Reactor
Figure below shows the diagram of a CSTR where inlet and outlet
streams are continuously fed and removed, respectively. Fluidized bed
reactors are sometimes treated as stirred tank reactors . The key
characteristics of a CSTR are steady-state operation, good mixing
leading to spatially uniform concentration and temperature, and the
condition of the outlet stream being the same as the condition in the
reactor. CSTR is used for liquid-phase reactions and is suitable for
viscous liquids.
(a) Schematic of a CSTR and (b) a fluidized bed reactor.

PROCESS
FLOW
DIAGRAM
A PFD is a diagram commonly used in chemical and process
engineering to describe the general flow of plant processes and
equipment. PFD displays the relationship between major
equipment of a plant facility and does not show minor details
such as piping and control designations. Another commonly
used term for a PFD is a flow sheet. In drawing the flowchart,
one must know (or be able to determine) the total amount of the
flow within the stream and composition of the stream.
(a) Schematic of a CSTR and (b) a fluidized bed reactor.

As mentioned before, a PFD identifies all processes at a
facility. Each piece of equipment is labeled with a name and a
number assigned by the engineer or client and must be shown
on the PFD. Major flow streams are represented by arrow lines
directed from left to right in a diagram. Each stream line should
have a specification indication as a minimum unit number and
line number.
LABELING
PFD
An amount of 100 kg/h of a
mixture of 50% benzene and
50% toluene is separated in a
distillation column. The
distillate contains 90%
benzene and the bottom stream
composition is 95% toluene
(compositions are in weight
percent). Draw and label the
process flowchart, and specify
vapor and liquid streams

MULTIUNIT PFD
A stream containing 10.0 wt% acetone and the balance water enters a liquid/liquid extraction column where acetone is extracted with
methyl isobutyl ketone (MIBK). The solvent is a fresh feed of MIBK and a recycled stream consisting of MIBK with a small amount
of acetone. There are two streams leaving the liquid–liquid extraction process: a raffinate stream that contains only acetone and water,
and an extract stream that contains only acetone and MIBK. The extract stream goes to a distillation process. The overhead stream
from the distillation process is mainly acetone with some MIBK. The bottoms stream contains mainly MIBK with some acetone and
is recycled to the liquid–liquid extraction process. The overhead stream from the distillation tower contains 90% of the acetone in
stream 1. The overhead stream from the distillation tower also contains four times as much acetone as it contains MIBK. Draw a flow
diagram for the process labeling all processing units and all streams. Give the information of the flow rate and/or composition. For
each stream in this process, indicate as much information as you know about that stream as given in the process description