I am chemical engineer magazine 6 2013

6/2013

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I am a Chemical Engineer
• We discuss Chemical Engineering and
provide some information and news.
• We would like to think of our page as an
exchange page of experience and
information.

Slogan
Connecting chemical engineers.

Vision
Improving the chemical Engineering skills to
meet the work environment & to decrease the
gap between study and work.

Mission
Gathering information about any chemical
engineering fields.

What Is Chemical Engineering?
Chemical engineering basically is applied chemistry. It is the
branch of engineering concerned with the design,
construction, and operation of machines and plants that
perform chemical reactions to solve practical problems or
make useful products.

What Is a Chemical Engineer?
Like all engineers, chemical engineers use math, physics, and
economics to solve technical problems. The difference
between chemical engineers and other types of engineers is
that they apply a knowledge of chemistry in addition to other
engineering disciplines. Chemical engineers sometimes are
called 'universal engineers' because their scientific and
technical mastery is so broad.

What Do Chemical Engineers Do?
Some chemical engineers make designs and invent new
processes. Some construct instruments and facilities. Some
plan and operate facilities. Chemical engineers have helped
develop atomic science, polymers, paper, dyes, drugs, plastics,
fertilizers, foods, petrochemicals... pretty much everything.
They devise ways to make products from raw materials and
ways to convert one material into another useful form.
Chemical engineers can make processes more cost effective or
more environmentally friendly or more
efficient. As you can see, a chemical
engineer can find a niche in any scientific
or engineering field.

Learn something about everything

What is the Function of a Gate Valve?
Definition
A gate valve, also referred to as a sluice valve, is a valve
that opens and closes to regulate fluid flow. A gate valve
opens by lifting a rectangular or round gate or wedge,
often called a sliding door, out of the fluid's path to allow it
to flow though.
Function
Gate valves are used in straight-flow fluid systems where a
minimum amount of friction is required. Unlike other
valves, gate valves are constructed to be used either
completely open or closed. If partially open, the fluid
velocity can damage the gate valve's seal and cause
leakage.
Stems
Gate valves contain either a non-rising or rising stem.
Rising stems are used as a visual indication of the valve
position and lift when a valve is open. Non-rising stems are
used for underground gate valves or when vertical space is
constricted.

Different types of Flowmeters with their
Diagrams :
i.
ii.
iii.
iv .
v.
vi.
vii.
viii.
ix.

Orifice Flowmeter
Venturi Flowmeter
Nozzle Flowmeter
Pitot Tube Flowmeter
Wedge Flowmeter
Vortex Flowmeter
Ultrasonic Flowmeter
Turbine Flowmeter
Magnetic Flowmeter

Manometer
A Manometer is a device which can be used to measure
pressure of fluids(i.e liquids and Gases).
PRINCIPLE: Manometers are those pressure measuring
devices which are based on the principle of balancing the
column of liquid (whose pressure is to be found) by the
same or another column of liquid. They are of two types
1. simple manometers
2. Differential manometers
simple manometers are those which measure pressure at a
point in a fluid containing in the pipe or a vessel. On the
other hand Differential manometers measure the
difference of pressure between any two points in a fluid
contained in a pipe or vessel.

Feedforward Control :
In contrast to feedback control, feedforward control acts
the moment a disturbance occurs, without having to wait
for a deviation in process variable. This enables a
feedforward controller to quickly and directly cancel out
the effect of a disturbance. To do this, a feedforward
controller produces its control action based on a
measurement of the disturbance.

When used, feedforward control is almost always
implemented as an add-on to feedback control. The
feedforward controller takes care of the major disturbance,
and the feedback controller takes care of everything else
that might cause the process variable to deviate from its
set point.

In our example of the heat exchanger, in which the major
disturbances come from changes in process flow rate, the
latter can be measured and used for adjusting the steam
flow rate proportionally. This is done by the feedforward
controller.

Implementing Feedforward Control :
Many PID controllers have an external connection for
adding an input from a feedforward controller. Otherwise
the output of the feedforward controller can be externally
added to the output of the feedback controller. Review
your controller documentation and take special care with
scaling the feedforward signal. Many PID controllers expect
the feedforward signal to be scaled between -100% and
+100%.

Feedforward and feedback control is often combined with
cascade control, to ensure that their control actions
manipulate the physical process linearly, eliminating
control valve nonlinearities and mechanical problems.
If several major disturbances exist, a feedforward
controller can be implemented for each of them. The
outputs of all the feedforward controllers can be added
together to produce one final feedforward signal. Only
consider disturbances that meet these criteria:
Measurable – if it can’t be measured you can’t control from
it Predictable effect on the process variable – most
disturbances will fall in this class Occur so rapidly that the
feedback control cannot deal with them as they happen.

Cascade Control :
Cascade Control Systems contain integrated sets of control
loops
* Primary Loop: Monitors the control variable and uses
deviation from its setpoint to provide an output to the
secondary loop.
* Secondary Loop: Receives its setpoint from the primary
loop and controls the reference variable accordingly.

Benefits of Cascade Control
1- Effectively accounts for external disturbances
2- Reduces dead time in variable response
3- Compatible with other Control Systems, such as FeedBack and Feed-Forward Control Architectures

Disadvantages of Cascade Control
1- Multiple control loops make physical and computational
architecture more complex
2- Additional controllers and sensors can be costly

What is the Difference between rising stem gate
valve and non rising stem gate valve?
Rising stem gate Valve - Stem threads are out side of valve
body and in no contact with fluid medium. Stem rises while
opening the valve (by hand wheel). Since
the stem threads are located outside
obviously it needs some more vertical
clearance space while opening the valve.

Non Rising Stem gate Valve - Stem threads are inside the
the valve body and it is in contact with fluid medium.
Hence, lot of chances for fouling the
threads and these types of valves only can
be used in clean liquids and gases. Less
vertical clearance space required while
opening the valve.

Foot valve: a check valve on the foot of a suction line to
prevent back-flow.
A suction valve or check valve at the lower end of a pipe; esp.,
such a valve in a steam-engine condenser opening to the air
pump.
-A foot valve is nothing more than a swing check valve operating
in the vertical position at the the liquid entry to the vertical
suction line of a sump pump or another type of pump that has a
negative suction lift due to gravity - i.e., the pump is usually
located above the liquid level of the suction vessel or container. If
there is any logic in this description it is that the check valve is
located at the "foot" of the vertical pipe run. But it has to be
understood that we are talking about a check valve - not another
type of valve. The function of a foot valve is to contain the liquid
inventory within the pump casing and the suction line in the
event the pump is shut down or stopped. This action preserves
the liquid priming of the pump and allows for a successful, instant
liquid pumping start up during the next, subsequent pump startup. This is especially useful when the
pump is started from an isolated
location and there is no one around to
manually prime the pump with liquid
prior to start up.

Float type steam trap :
The Float type steam trap consists of a chamber having inlet and
outlet ports. The chamber contains a stainless steel ball-float
connected by a lever to the inside of the chamber wall. In the
body of the trap, the outlet port has valve seats fitted to
accommodate a valve plug which is fitted to the lever between
the float and the chamber wall.

When the trap is empty, the ball float is down and the outlet
valve is closed. As condensate (water) enters the trap and forms a
level, the ball begins to float and rise with the rising level.
At a pre-set level the rising lever actuates the valve plug and
opens the valve. Condensate passes out of the trap, the level falls
and the valve closes down. In this way, the level of condensate is
controlled and no steam loss is incurred. This type of trap works
well with heavy or light condensate loads.

THE THERMOSTATIC STEAM TRAP
This type of steam trap has a sealed, internal bellows element
filled with a liquid which has a boiling point about 25°C below
that of water. Heating or cooling of the element causes it to
expand or contract. The bottom of the element is connected to a
valve which fits into a seat in the trap body.
When the trap contains steam, the bellows is expanded by boiling
the liquid inside and the valve is closed. As condensate fills the
trap, it cools and the bellows begins to contract as its internal
liquid stops boiling. This opens the valve and the liquid is drained
off and then replaced by steam. Once again the bellows expands
and closes the valve.

Relief Valves :
* Pressure relief valve - A spring-loaded pressure relief valve
which is designed to open to relieve excess pressure and to
reclose and prevent the further flow of fluid after normal
conditions have been restored. It is characterised by a rapidopening 'pop' action or by opening in a manner generally
proportional to the increase in pressure over the opening
pressure. It may be used for either compressible or
incompressible fluids, depending on design, adjustment, or
application.
This is a general term, which includes safety valves, relief valves
and safety relief valves.
Safety valve - A pressure relief valve actuated by inlet static
pressure and characterized by rapid opening or pop action.
Safety valves are primarily used with compressible gases and in
particular for steam and air services. However, they can also be
used for process type applications where they may be needed to
protect the plant or to prevent spoilage of the product being
processed.

Relief Valves :
* Relief valve - A pressure relief device actuated by inlet static
pressure having a gradual lift generally proportional to the
increase in pressure over opening pressure.
Relief valves are commonly used in liquid systems, especially for
lower capacities and thermal expansion duty. They can also be
used on pumped systems as pressure overspill devices.
* Safety relief valve - A pressure relief valve characterised by
rapid opening or pop action, or by opening in proportion to the
increase in pressure over the opening pressure, depending on the
application, and which may be used either for liquid or
compressible fluid.
In general, the safety relief valve will perform as a safety valve
when used in a compressible gas system, but it will open in
proportion to the overpressure when used in liquid systems, as
would a relief valve.

Fluidized-Bed Heat Exchangers:
In a fluidized-bed heat exchanger, one side of a two-fluid
exchanger is immersed in a bed of finely divided solid material,
such as a tube bundle immersed in a bed of sand or coal particles.
At a ‘‘proper’’ value of the fluid velocity, the upward drag force is
slightly higher than the weight of the bed particles. As a result,
the solid particles will float with an increase in bed volume, and
the bed behaves as a liquid. This results in a uniform temperature
for the total bed with an apparent thermal conductivity of the
solid particles as infinity.
Chemical reaction is common on the fluidized side in many
process applications, and combustion takes place in coal
combustion fluidized beds.
The common applications of the fluidized-bed heat exchanger are
drying, mixing, adsorption, reactor engineering, coal combustion,
and waste heat recovery.

There are four processes in the Rankine cycle. These states are
identified by numbers (in brown) in the above Ts diagram.
Process 1-2: The working fluid is pumped from low to high
pressure. As the fluid is a liquid at this stage the pump requires
little input energy.
Process 2-3: The high pressure liquid enters a boiler where it is
heated at constant pressure by an external heat source to
become a dry saturated vapor. The input energy required can be
easily calculated using mollier diagram or h-s chart or enthalpyentropy chart also known as steam tables.

Process 3-4: The dry saturated vapor expands through a turbine,
generating power. This decreases the temperature and pressure
of the vapor, and some condensation may occur. The output in
this process can be easily calculated using the Enthalpy-entropy
chart or the steam tables.

Process 4-1: The wet vapor then enters a condenser where it is
condensed at a constant temperature to become a saturated
liquid.
by the condensers.

In an ideal Rankine cycle the pump and turbine would be
isentropic, i.e., the pump and turbine would generate no entropy
and hence maximize the net work output. Processes 1-2 and 3-4
would be represented by vertical lines on the T-S diagram and
more closely resemble that of the Carnot cycle. The Rankine cycle
shown here prevents the vapor ending up in the superheat region
after the expansion in the turbine,which reduces the energy
removed by the condensers.

THERMO-DYNAMIC STEAM TRAP:
This type of steam trap, when
installed, has a strainer fitted
into the line upstream of it, to
remove solid particles of scale .
.etc. As condensate enters the
trap, through the inlet pipe
with the steam pressure
behind it, a metal disc is
forced upwards into a small
chamber and the condensate
passes under the disc into the
outlet pipe.
The velocity of the water
passing through the trap is low, even when the pressure is high.
This is due to the density of the water being high compared to
that of steam and the fact that, within the trap, the fluids pass
through an angle of 180°.
When all of the water has been displaced, steam begins to flow.
The greater velocity of the steam below the disc and the sudden
change of direction, causes a pressure drop under the disc which
pulls it down onto its seat and stops the steam flow.
The steam pressure in the chamber above the disc will be the
same as the line pressure thereby holding the disc on its seat.
When the steam above the disc cools and condenses, the
chamber pressure falls and the disc is forced upwards again by
the line pressure.
If only steam passes into the trap, the above process is repeated
with a small release of steam until the disc drops again.

Every magazine we will
introduce a special course,
Today our course is PUMP

AN INTRODUCTION TO PUMPING EQUIPMENT

WHAT IS THE PUMP?
Pumps are machines which supply energy to a liquid in
order to move it from place to another.
The method that is used to supply this energy to the liquid
determines the category into which the pump is placed and
the system between the pump and the liquid final destination
defines the application.

Water Flood

Refinery

Transportation

Pumps enable a liquid to:
1. Flow from a region or low pressure
to one of high pressure.
2. Flow from a low level to a higher
level.
3. Flow at a faster rate.

Pumps vary considerably in their size, construction
and principle of operation.

There are two main categories of pump:
•
•

Rotodynamic pumps.
Positive displacement pumps.
PUMP
Rotodynamic

Positive displacement

Centrifugal
Rotary

Reciprocating

Axial flow
Mixed flow
Gear

Piston

Turbine
Lobe

Sliding Vane

Screw

Diaphragm

Plunger

Centrifugal Pumps:
Also known as rotary pumps, centrifugal pumps have a
rotating impeller, also known as a blade, that is immersed in
the liquid. Liquid enters the pump near the axis of the impeller,
and the rotating impeller sweeps the liquid out toward the
ends of the impeller blades at high pressure.
For low flows and high pressures, the action of the impeller is
largely radial.
For higher flows and lower discharge pressures, the direction of
the flow within the pump is more nearly parallel to the axis of
the shaft, and the pump is said to have an axial flow. The
impeller in this case acts as a propeller.

The transition from one set of flow conditions to the other is
gradual, and for intermediate conditions, the device is called a
mixed-flow pump.

Positive-displacement Pumps:
A variety of positive-displacement pumps are also
available, generally consisting of a rotating member with
a number of lobes that move in a close-fitting casing. The
liquid is trapped in the spaces between the lobes and
then discharged into a region of higher pressure. A
common device of this type is the gear pump, which
consists of a pair of meshing gears. The lobes in this case
are the gear teeth.
What is the main difference between kinetic and
positive displacement pumps ?
The main difference between kinetic and positive displacement
pumps lies in the method of fluid transfer.
A kinetic pump imparts velocity energy to the fluid, which is
converted to pressure energy upon exiting the pump casing

A positive displacement pump moves a fixed volume
of fluid within the pump casing by applying a force to
moveable boundaries containing the fluid volume.

Positive displacement pumps are also divided into two major
pump categories : reciprocating & rotary.
Reciprocating pumps transfer a volume of fluid by a
crankshaft,eccentric cam or an alternating fluid pressure acting
on a piston, plunger or a diaphragm in a reciprocating motion.
The Table below outlines some of the main differences
between centrifugal pumps, reciprocating pumps and rotary
pumps. Note that “centrifugal”, “reciprocating” and “rotary”
pumps are all relatively broad categories. The table below
provides a comparison of features between these pump
categories that generally holds true.
Also, note that Table lists typical maximum flow rates and
heads. It is possible to build special pumps outside the upper
bounds of the pressures and flow rates
listed, but such pumps would be
prohibitively expensive for most
applications.

Centrifugal Pumps

Reciprocating
Pumps

Medium/High Capacity,
Low/Medium Pressure

Low Capacity,
High Pressure

Low/Medium
Capacity,
Low/Medium
Pressure

Maximum Flow
Rate

100,000+ GPM

10,000+ GPM

10,000+ GPM

Low Flow Rate
Capability

No

Yes

Yes

6,000+ PSI

100,000+ PSI

4,000+ PSI

Requires Relief
Valve

No

Yes

Yes

Smooth or
Pulsating Flow

Smooth

Pulsating

Smooth

Variable or
Constant Flow

Variable

Constant

Constant

No

Yes

Yes

Requires Less Space

Requires More
Space

Requires Less Space

Lower Initial
Lower Maintenance
Higher Power

Higher Initial
Higher Maintenance
Lower Power

Lower Initial
Lower Maintenance
Lower Power

Suitable for a wide
range including clean,
clear, non-abrasive
fluids to fluids with
abrasive, high-solid
content.

Suitable for clean,
clear, non-abrasive
fluids. Speciallyfitted pumps suitable
for abrasive-slurry
service.

Requires clean,
clear, non-abrasive
fluid due to close
tolerances

Not suitable for high
viscosity fluids

Suitable for high
viscosity fluids

Lower tolerance for
entrained gases

Higher tolerance for
entrained gases

Parameter
Optimum Flow and
Pressure
Applications

Maximum Pressure

Self-priming
Space
Considerations
Costs

Fluid Handling

Rotary Pumps

Optimum
performance with
high viscosity fluids
Higher tolerance for
entrained gases

Centrifugal Pumps Capacity:
The wide variety of centrifugal pumps manufactured offer a
relatively large range of available capacities. Radial-flow and
mixed flow pumps are used for low to medium capacity
applications. For high capacity applications, axial-flow pumps
are capable of delivering flow rates in excess of 100,000 gpm.
Centrifugal pumps are not stable at low flow rates, although
there are special low-flow centrifugal pumps available that can
deliver flow rates less than 10 gpm. However, for extreme lowflow applications (< 1 gpm), positive displacement pumps are a
better selection.

Reciprocating & Rotary Pumps Capacity:
Reciprocating and rotary pumps are capable of capacities
ranging from low to medium, with flow rates peaking at
10,000+ gpm. In theory, reciprocating pumps can be
manufactured to deliver more capacity, but they become
prohibitively large and expensive at high flow rates. Both
reciprocating and rotary pumps are capable of delivering
product at extremely low flow rates (fractions of a gpm),
making them particularly suitable for many chemical injection
applications.

Why it is necessary to install a relief valve on the
discharge of the Reciprocating or Rotary pumps ?
Because both reciprocating and rotary pumps will continually
increase pressure when pumping against a closed discharge to
the extent allowed by the driver’s horsepower. This can result
in overpressure of the pump or piping components, so it is
necessary to install a relief valve on the discharge of the pump
capable of discharging the full capacity of the pump.

Why it is not necessary to install a relief valve on the
discharge of the Centrifugal pumps ?
A centrifugal pump’s pressure rise is limited to the shut-off
pressure on the pump curve, which is always less than the
design pressure of the pump (and the piping system if properly
designed). A relief valve is only needed if no other measures
are provided to detect low flow conditions and shut down the
pump to prevent damage. The relief valve need only be sized
to pass the minimum flow rate required to maintain stable flow
and prevent excessive temperature rise.

Centrifugal pumps and most rotary pumps provide smooth,
non-pulsating flow, while reciprocating pumps produce a
pulsating flow.
A pulsating flow may require special design considerations in
the piping system. If the pump is not located near the suction
source, then acceleration head can contribute to low NPSHA
problems, which may require the installation of a suction
stabilizer.
A pulsation dampener may need to be installed in the discharge
piping to reduce pressure surges resulting from the pulsating
flow.

Centrifugal Pumps Variable or Constant Flow:
Centrifugal pumps operate on a variable-flow, variable-head
curve. As the discharge pressure decreases, the pump delivers
a higher flow rate.
Centrifugal pumps are favored where process conditions often
require varying flow rates. For example, a level control valve
must throttle the flow rate from a vessel to maintain a constant
level in the vessel. A centrifugal pump is well suited to handle
this process condition.

Reciprocating & Rotary Pumps Variable or Constant
Flow:
At any given speed, reciprocating and rotary pumps operate at
a constant flow rate regardless of the discharge
pressure. There are specific applications that require either
constant flow or variable flow. Metering pumps rely on a
constant flow at varying pressures, which makes reciprocating
pumps and rotary pumps suitable for this application. Piston
pumps used for metering will often use an adjustable stroke
length to allow the operator to vary the flow rate to meet the
system requirements.
whereas a positive displacement pump would either require a
continuous recycle to suction or a variable speed driver to
accommodate the variable flow.

Self-priming :
Reciprocating and rotary pumps are self-priming. This is an
important consideration where a prime cannot be maintained
on the pump. Centrifugal pumps are not inherently selfpriming, although some manufacturers do specially design selfpriming units. External priming sources, such as an eductor or
vacuum pump can also be employed.


Costs Considerations :
The reciprocating pump will generally have higher initial capital
costs and will require more space relative to the centrifugal
pump or the rotary pump.
The reciprocating pump will generally have higher maintenance
costs relative to the centrifugal pump or the rotary pump.
The centrifugal pump will generally have higher annual power
consumption costs relative to the reciprocating pump or the
rotary pump because of lower efficiencies.

Costs Considerations :
A pump that is selected for an application outside of its
optimum operating parameters will almost certainly not follow
these rules. For example, a rotary pump operating in a high
pressure, abrasive-slurry service would probably have higher
maintenance costs than a properly selected reciprocating
pump. The close running clearances (particularly for high
pressure service) required in the rotary pump would likely
result in premature wear and frequent maintenance.


Centrifugal Pumps Fluid Handling:
Centrifugal pumps are suitable for transferring a variety of
fluids ranging from clean, clear non-abrasive fluids to abrasiveslurries. However, a centrifugal pump is not the best choice for
pumping highly viscous fluids due to dramatic drops in
efficiency at high viscosities. Centrifugal pumps are not
normally specified for viscosities higher than about 4,000
SSU. Centrifugal pumps are also not well suited to pumping
entrained air. Most centrifugal pumps can handle up to about
2% entrained gas and specially-designed pumps can handle up
to about 10%.

Reciprocating Pumps Fluid Handling:
Reciprocating pumps are well suited for transferring clear, nonabrasive fluids, as well as abrasive slurries. In fact, the
relatively low velocities of moving parts within a reciprocating
pump make it particularly resistant to erosion in abrasive-slurry
applications, provided that the pump is properly designed for
the service. Reciprocating pumps maintain high efficiencies
when pumping highly viscous fluids and can easily handle 50%
and higher volumes of entrained gas.


Rotary Pumps Fluid Handling:
Rotary pumps can also handle high viscosity fluids and high
volumes of entrained gas. In fact, many rotary pumps operate
at their best efficiency at higher viscosities. However, rotary
pumps are not well suited for pumping corrosive fluids or fluids
with abrasive solids because of close clearances between
rotating and static pump components.

Summary
One fact that must always be remembered: A pump does not
create pressure, it only provides flow. Pressure is a just an
indication of the amount of resistance to flow.
there are many different subcategories of pumps within these
broad categories and there are many regions of overlap where
multiple types of pumps in the same category and even in
different categories would be suitable. Since every pump
application is unique, each of the factors that influence the
pump selection must be considered in detail.

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interview

The fluid property, due to which, mercury does not wet the
glass is
A. surface tension
B. viscosity
C. cohesion
D. Adhesion

Laminar flow of a Newtonion fluid ceases to exist, when the
Reynolds number exceeds
A. 4000
B. 1500
C. 2100
D. 3000
The normal stress is the same in all directions at a point in
a fluid, when the fluid is
A. non-viscous.
B. incompressible.
C. both (a) and (b).
D. having no motion of one fluid layer relative to the other.
Head developed by a centrifugal pump depends on its
A. speed
B. impeller diameter
C. both (a) and (b)
D. neither (a) nor (b)

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In Centrifugal compressors, why does surge occurs?
A. Surge occurs due to low pressure in the suction drum.
B. Surge occurs due to low flow at suction.
C. Surge occurs due to high speed.
D. None of the above (neither A, nor B, nor C)
Loading/unloading ethylene requires:
A. Loading arm overhaul
B. Loading arm dismantling
C. Loading arm cooling-down
Why is pH measured in the boiler blowdown?
A. To adjust the flow
B. To prevent corrosion
C. To inject detergent
D. To inject polyelectrolyte
What is the physical meaning of saturated steam?
A. It is a steam at low pressure.
B. Steam at Dew point or at a point where all water
transferred to vapor.
C. It is a steam at high pressure.
Sulphur dust is:
A. Irritant & flammable
B. Irritant and toxic
C. Toxic
D. Corrosive only

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Which of the following statement is not correct?
A. Traceability of the product is optional
B. Processes transform inputs into outputs
C. Quality policy determines organisational objectives
D. Efficiency is the relationship between result and resources
In steam boilers, why is a continuous blowdown provided.
A. To control level in steam boiler.
B. To control the quality of steam.
C. To control the pressure.
D. All the above (A + B + C).
What is the purpose of the fast purging in a steam boiler?
A. To remove the sludge from the boiler bottom
B. To replace part of the water with fresh make-up water
C. To sample the water to check for composition
D. To check the level inside the boiler drum
Which of the following is not a quality principle?
A. Customer focus
B. Continuous improvement
C. Process approach
D. Maximum production on-specification
How many carbon moles are in 6.00 g of C?
A. Two moles.
B. Three moles.
C. Half mole.
D. One mole.

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On process plants why are process/utilities connections
equipped with flexibles and specific fittings?
A. To make sure operator will recognize them
B. To prevent any mix of utilities
C. To facilitate the work of the operator
D. To prevent purging with the wrong utility and/or
hydrocarbon contamination
In a distillation column, what is flooding?
A. It is the level increase in the column.
B. Pressure drop in the column.
C. It occurs when the liquid/vapour traffic is disturbed due
to high velocity of the vapour and liquid is entrained
upwards.
D. It occurs when the liquid/vapour traffic is disturbed due to
low velocity of the vapour and liquid weeps through the plates.
In a distillation column, what is the sensitive tray?
A. It is the tray at which the feed to the column is placed in
order to minimize temperature upsets.
B. It is the tray at which temperature in the stripping
section is controlled.
C. It is the tray at which most of the light and heavy
components are separated and fractionation occurs.

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For centrifugal pumps, what is cavitation?
A. Cavitation occurs due to low level in suction drum.
B. Cavitation occurs when the NPSH available is less than
the required NPSH.
C. It is the presence of vapour in the suction drum.
D. None of the above(neither A, nor B, nor C)

Why is saturated steam used in the different reboilers in the
plant and not superheated steam?
A. To prevent corrosion
B. To reduce reboiler duty
C. To limit thermal exchange
D. None of the above(neither A, nor B, nor C)
For steam turbines, why is heating necessary before start
up?
A. To get more power.
B. More discharge pressure.
C. More speed.
D. To avoid thermal shock.
What is Latent Heat?
A. It is the heat of a substance at ambient temperature.
B. Heat required to vaporise or to condense a gas.
C. Heat required to increase the temperature of 1 kg a
substance by 1C.
D. Heat required to melt or to freeze a liquid.

Learn how to have

What is Partial Pressure?
A. It is the pressure of a substance at ambient temperature.
B. Pressure required to vaporize or to condense a gas.
C. It is the pressure of individual component in a mixture
of gas.

What is Boiling Point?
A. It is the temperature required to vaporize the liquid.
B. Pressure and temperature drop in the column.
C. It is the temperature at which the vapour pressure of a
liquid is equal to the atmospheric pressure.
The net positive suction head (NPSH) of a centrifugal pump
is defined as the sum of the velocity head and the pressure
head at the
A. discharge.
B. suction.
C. suction minus vapor pressure of the liquid at suction
temperature.
D. discharge minus vapor pressure of the liquid at the
discharge temperature.
Pour point and freezing point is equal for
A. petrol
B. diesel
C. water
D. crude petroleum

Learn how to have

In cracking furnaces or fired heaters, what is the advantage
of using excess air in combustion?
A. Fuel consumption will be reduced.
B. Temperature will be better.
C. Complete combustion is ensured.

Which of the following fractions of a crude oil will have the
maximum gravity API (i.e. °API) ?
A. Diesel
B. Gasoline
C. Atmospheric gas oil
D. Vacuum gas oil
Short distance transportation of grain, gravel, sand, ash,
asphalt etc. is done by using a __________ conveyor.
A. flight
B. slat or drag
C. ribbon
D. screw
Friction factor for fluid flow in pipe does not depend upon
the
A. pipe length.
B. pipe roughness.
C. fluid density & viscosity.
D. mass flow rate of fluid.

Learn how to have

Which one of the following is incombustible ?
A. H2
B. C2H2
C. CCl4
D. S
Fog is an example of colloidal system of
A. solid dispersed in gas.
B. solid dispersed in liquid.
C. liquid dispersed in gas.
D. gas dispersed in liquid.
In troposphere (the weather domain), the temperature 't' at
height 'h' above the sea level in metres is given by (where,
temperature at sea level is 15°C and t is in °C.)
A. t = 15 - 0.0065 h
B. t = 15 + 0.0065 h
C. t = 0.0035 h - 15
D. t = 15 - 0.0035 h
A high pressure boiler generates steam at a pressure greater
than __________ kg/cm2 .
A. 10
B. 50
C. 30
D. 80
Which of the following is not categorised as a "mechanical
operation" ?
A. Agitation
B. Filtration
C. Size enlargement
D. Humidification

Learn how to have

What is the kind of the following valve ?

slide valve

gate valve

expansion valve

wafer check valve

Learn how to have

What is the kind of the following valve ?

needle valve
Foot valve

non return valve or
one way valve or check valve

Butterfly Valve

Learn how to have

Send your question and we
will post it on our page wall

LIST of QUESTIONS
1.

i wanna attempt to construct a viable home based
ammonia or urea production unit. using methane or
LPG. In your opinion, is this possible to do profitably?
And if it is cud u send me links to some literature that
may help me out. Thanks in advance
2. If there any chemical which when mixed with water
gives specific density higher than if water was mixed
with Baryte?
3. What is yield of a process ?
4. What are differences between HETP and HTU for
column
5. could you give me some information for the glycerin
process
6. Difference between total dead heat & dead head at
max. impeller centrifugal pump
7. Is stichoimetry compulsory for chemical engineering ?
8. dose the activation energy change with particle size
when finding the rate equation? or in another way dose
the activation energy affect with the particle size when
finding the rate equation?
9. What chemical reaction not exothermic or endothermic
or third way is possible or not ?
10. I want references about bio gas plz
11. how to prepare organic fertilizer at home from domestic
waste?

Send your question and we will post it on our page wall

ONE of page fans has a question
and needs an answer

LIST of QUESTIONS
12. if non condensable is added inthe distillation column ,
so what's the effect in the dew point of the distillate .
.whether it will increase or decrease? And why
13. What is the cheapest form of polymer?
14. What is the difference between a simple and long chain
polymer?
15. can any one help me to find information about Harriot
method for calculation of diffusion coefficient
16. what is the MAX temperature allowable for a heat
exchanger AS CWS COOLING WATER SUPPLY ?
17. can you give me references for production of dimethyl
ether
18. What role does the Ventury effect have on mixing
chemicals?
19. How can i check the purity of Kcl?
20. Which chemical will you add to water to increase the
viscocity to 40 centipose?
21. Esterification reaction is endothermic or exothermic?
22. can u suggest me whether chemical engg. Hv scope in
India...?
23. What is the difference between extensive and intensive
properties ?
24. can u explaine about split type heat exchanger
25. How much water occupy in a 1" inch s.s pipe of length
10 meter ??? How can we calculate?


and needs an answer

LIST of QUESTIONS
26. What is wet vacuum and dry vacuum and compare both
27. why hydrogen is exception for joule thomson effect?
28. i want to know where the distillation coulumn will be
used in a horizontal position? and how will be the
operating conditiones?
29. Can we use CSTR for gaseous reactant ?
30. Can we use liquid DAP instead of granules? As it will
reduce the cost of granulation,drying, cooling
31. Would you please tell me what is the maximum suction
head for centrifugal pump in case of negative suction??
32. xplain d principles of the heat xchanger wen fluid flows
counter currently
33. how nuclear fusion and fission will takes place at a time
in hydrogen bomb?
34. uses of vinyl sulphone ester ?


and needs an answer

Tawedzerwa Masuka
i wanna attempt to construct a viable home based
ammonia or urea production unit. using methane or
LPG. In your opinion, is this possible to do profitably?
And if it is cud u send me links to some literature that
may help me out. Thanks in advance

Name

comment

Ah.yehia

this attach will help you
http://www.mediafire.com/download/w
7ftn158rtbinx3/ammonia.rar

Nidhi Satwara
If there any chemical which when mixed with water gives
specific density higher than if water was mixed with
Baryte?

Name
Er Dhaval Patel

comment
Molybdenum sulphate with solution
pH 4-5.


and needs an answer

Atul Gourh
What is yield of a process ?

Name

Ah.yehia

comment
The yield of a chip manufacturing process
refers to how much salable product is able
to be produced. This can be an absolute
number (chips per day for example) or a
factor that refers to the percentage of total
chips manufactured that passed
inspection and were able to be sold. Of
course, the higher the yield, the more chips
that can be produced for (basically) the
same cost, which allows costs and hence
prices to decrease.
http://www.pcguide.com/ref/cpu/char/mfg
Yield-c.html
http://www.sixsigmatraining.org/six-sigmaprojects/how-to-calculate-processyields.html


and needs an answer

Atul Gourh

continue


Name

comment

Ah.yehia

A manufacturing process has a 70%
yield, meaning that 70% of the products
are acceptable and 30% are defective

Abdelrahman
Mohamed
Khalid

i think yield means that the product we
need & and remaining byproducts aren't
important like the main one.

Mohamed
Wageeh

amount of desired product/amount of
undesired product(from side reaction)

or even from a single step reaction.. but
Hussam Nabawy in this case a yield of a reaction will
express the conversion!!
Naveed Ali
Koondhar
Saad Raad

Simply we can say the rate of production
the desired material(product)/total
material(feed)


and needs an answer

Atul Gourh

continue


Name

comment

the yield is simply what we have got as a
product at the end of the process.
Yuosuf Al Faraj
yield is related to the product while
conversion related to the reactant .
Syed Shah
Jehan Gillani

MEASURE OF PRODUCTIVITY HOW
EFFICIENTLY GETTING THE THEORETICAL
MAX.POSSIBLE OUTPUT BY GIVING
SPECIFIC INPUT

Mohamed
Hassn
Waheed

I think it is the percentage of conversion
from input raw material to the main
product


and needs an answer

Tarkeshwar Pandey
What are differences between HETP and HTU for column

Name

comment

Nickkhil Batra

hetp =height eqivalent to theoretical
stage .it is height of packing that provides
seperation equal to tray

Nickkhil Batra

whereas htu is height of transfer unit
which shows seperation efiiceincy of
packinh

Prince Singla

Nickkhil: if HETU=HTU then wat u
interpret about operating line and
equilibrium line.....means are they
coincide or // or perpendicular...??

Nickkhil Batra

i think operating lines are parallel in that
case

Zé Maurício
Jawwad Khan
Er Dhaval
Patel

HETP/HTU=eficiciency
HETP is generally used for distillation.. And
HTU for gas absorption or stripping....
Hetp=shows height of theorytical stages
&htu=shows that height of colum


and needs an answer

Ivan Montiel
could you give me some information for the glycerin
process

Name

comment

Abdallah ELGharbawy

glycerin can be produced via two routes :
the first one from oil and fats by reaction
of oil with alchol (methanol & ethanol )
and then we get biodiesel and glycerol

Abdallah ELGharbawy

the second routes from chlorination of
propylene to give allyl chloride, which is
oxidized with hypochlorite to
dichlorohydrins, which reacts with a strong
base to give epichlorohydrin.
Epichlorohydrin is then hydrolyzed to give
glycerol. Chlorine-free processes from
propylene include the synthesis of glycerol
from acrolein and propylene oxide.

Er Dhaval
Patel

Glycerine is bye product of soap mfg and
produce of fat or oile

Prejilesh
Vanimel

Triglycerides of fatty acid(oil) can split into
fatty acid &glycerin with high
temprature&pressure


and needs an answer

Mohit Tiwari
Difference between total dead heat & dead head at max.
impeller centrifugal pump

Name

comment
You can deadhead a centrifugal pump if
you operate it full of liquid with the inlet
and outlet valves closed, so there is no
flow through the pump. In this case, the
rotating component of the pump (impeller)
will continue to agitate the same volume
of liquid.

Ah.yehia

Danger
The danger of deadheading a centrifugal
pump is that, as the liquid rotates,
frictional forces cause its temperature to
rise to the point where it vaporises. The
vapour disrupts cooling of the pump and
may cause excessive wear and tear to its
bearings. Deadheaded centrifugal pumps
have been known to explode even if they
contain just water or brine.


and needs an answer

Mohit Tiwari

continue

Difference between total dead heat & dead head at max.
impeller centrifugal pump

Name

comment

Ah.yehia

Protection
A centrifugal pump can be protected from
the effects of deadheading by fitting a line,
upstream of the outlet valve, to recycle
liquid back to the inlet valve. The diameter
of the line should be sufficient to recycle
enough liquid to prevent the pump
overheating.


and needs an answer

Faizan Arshad
Is stichoimetry compulsory for chemical engineering ?

Name
Narendra
Naren Kumar

comment
s it's important

Duraisamy
s ofcourse.
Gopalakrishnan
Devendra
Gurjar
Muneeb Ur
Rahman
Junaid Ahmed

Yes
Yes as it helps to achive desired product
details. As well as it izs the basis for mass
and heat transfer calculations which are
used to design equipments.
yes

Er Dhaval Patel Yes it is important


and needs an answer

Edmon A. Qusar
dose the activation energy change with particle size
when finding the rate equation?
or in another way dose the activation energy affect with
the particle size when finding the rate equation?

Name

comment

Mohit Tiwari

I think it is only function of temperature
hence will not change with particle size

Jama Salimov

students opinion: activation energy can be
calculated using Arrhenius equation,
which is k=-A*e^(-Ea/RT)
I don't see a direct correlation, but
increased particle size will give smaller
mass transfer area, hence heat transfer
area will be lowered, which indirectly
impacts rate of equation. I doubt there is
a strong impact.

Mohit Tiwari

I think particle size matters in collision
theory as it reduces the no. of affecting
collision of all particles hence reduction in
temp & rate reaction but no effect in
consideration for arrhenius equation


and needs an answer

Edmon A. Qusar

continue

dose the activation energy change with particle size when
finding the rate equation?
or in another way dose the activation energy affect with
the particle size when finding the rate equation?

Name

comment

Large particle size as per collision theory
Mohit Tiwari will reduce the kinetic energy & hence
activation energy
Malus
Prathmesh

nope activation energy will not
chnge...mohit correctly pointed out.....it is a
function of temperature

Abdallah ELGharbawy

activation energy only depend on
temperature

Muneeb Ur
Rahman

In collision theory, formation of products
takes place when reactant molecules collide
with a certain minimum energy to form
product molecules. Hence at same
temperature more energy is required by
bigger molecule to move and collide
compared to smaller one. Therefore
activation energy is more for bigger
molecule at constant temperatue.


and needs an answer

Gokul singh
What chemical reaction not exothermic or endothermic

Name

comment
* An endothermic reaction is any chemical
reaction that absorbs heat from its
environment. Here's a list of examples of
endothermic reactions. You can use these
when asked to cite an example or to get ideas
to set up a demonstration of an endothermic
reaction or process.

Ah.yehia

* Endothermic Chemical Reactions
reaction of barium hydroxide octahydrate
crystals with dry ammonium chloride
dissolving ammonium chloride in water
reaction of thionyl chloride (SOCl2) with
cobalt(II) sulfate heptahydrate
mixing water and ammonium nitrate
mixing water with potassium chloride
reacting ethanoic acid with sodium carbonate
photosynthesis (chlorophyll is used to react


and needs an answer

Gokul singh

continue

What chemical reaction not exothermic or endothermic

Name

comment
Endothermic Chemical Reactions
carbon dioxide plus water plus energy to make
glucose and oxygen)
Endothermic Processes

Ah.yehia

* These examples could be written as chemical
reactions, but are more generally considered
to be endothermic or heat-absorbing
processes:
melting ice cubes
melting solid salts
evaporating liquid water
converting frost to water vapor (melting,
boiling, and evaporation in general are
endothermic processes)
making an anhydrous salt from a hydrate
forming a cation from an atom in the gas phase
splitting a gas molecule
separating ion pairs
cooking an egg
baking bread


and needs an answer

‫اسالم احمد غانم‬
I want references about bio gas plz

Name
Michał
Kisielewski

comment
http://www.amazon.com/Biogas-WasteRenewable-ResourcesIntroduction/dp/3527327983

Selvavinayagam Santhanam
how to prepare organic fertilizer at home from domestic
waste?

Name
Abdallah ELGharbawy

Gokul Singh

comment
by anaerobic digestion
Like a composte, we take a large chamber
and biodegradable waste collect in this
chamber, add water in this chamber, and
aerobic and anaerobic degration take place,
the reaction enffluent or product use as a
organic fertiliser.


and needs an answer

Sahil Satwara
if non condensable is added inthe distillation column , so
what's the effect in the dew point of the distillate .

Name

comment

Peto Wagih

Look, I'm not sure of my answer but dew
point is the point at which the first drop of
liquid appears, So assuming that there is no
chemical reaction between the non
condensing material added and the existing
material and also assuming the same
pressureand temperature applied, I don't
see a reason why should dew point change
in the first place....I mean, it is function of
pressure and temperature in the first place
so by not changing these factors all what
changes is the "amount" of liquid not "dew
point".

Ahmed Yehia i think it has no effect

ĀĥMệd
HĀşşan

INCREASES DUE TO INCREASE IN PRESSURE
!!


and needs an answer

Sahil Satwara

continue


Name

comment

Mohit
Tiwari

When vapor condenses in condenser of
column @dew point provide a wet surface
but then non condensable surrounds this
surface & then vapor will first diffuse
through this film of non condensable
(additional gas phase resistance) which
provide resistance to vapor reaching
towards dew point hence dew point
increases & load of condenser increase &
therefore reflux ratio decreases & hence
will be requirement of more no. of trays in
enriching section of column.

Mohit
Tiwari

as i think non condesable provide resistance
to vapor i.e work like inert & there will be
problem in phase transfer from bubble pt.
to dew point

Osama
Abdallha

decreases because of high pressure
which will be developed


and needs an answer

Sahil Satwara

continue


Name
Abo Gooda

Clint
Regondola
Mohammed
Zé Maurício

comment
I think it will decrease

increases due to Dalton's and Raoult's law

pi dec. (Dalton); xi dec. (Raoult); then yi inc.
and dew point increase.


and needs an answer

Nidhi Satwara
What is the cheapest form of polymer?

Name
Zeeshan Amjad Malhi
Abdelrahman Mohamed
Khalid
Alexander John Rico
Jeevarathnam Joseph
Raghu Can Can
Tulio Yterbio Fernandes
Vale
Harish Ch
Gokul Gokz
SaintYago Pincay
Gopal Danu

comment
polythene
linear polymer
polyethylene

Polythene
polythene
It's polyethen

polystyrene
polyethen
polyethylene is the most
economic globally
1polyethylin


and needs an answer

Nidhi Satwara
What is the difference between a simple and long chain
polymer?

Name

comment

Manne Nirmal
Kumar

A simple polymer consists of a long
chain of monomers joined by covalent
bonds
Polymers are repeating units of
atoms that form a chain, as the length
of this chain increases, the polymers
molecular weight increases.

Zeeshan Amjad
Malhi

Simple polymers are by definition
then, short chain, low atoms per
molecule, structures.
Longer chains equal larger molecular
weight polymers. Longer chains
incorporate polymers with a lot more
diversity in applications, like high
density plastics with high melting
temperatures, abrasion resistance
(rubber , urethanes and such)


and needs an answer

Nidhi Satwara

continue

What is the difference between a simple and long chain
polymer?

Name

comment

Mohamed Serag
Eldeen

if u ask about measuring? it must
have higher viscosity

Er Dhaval Patel

Simple polymer contain only
1monomar but chain polymer contain
monemar in series.

Yucef Tawes
can any one help me to find information about Harriot
method for calculation of diffusion coefficient

Name
Abhilash
Narnaware

comment
www.sciencedirect.com
u can search here


and needs an answer

AhMed HAssan
what is the MAX temperature allowable for a heat

Name

comment

Krunal Shah

It's depends on the condition...in hot
conditions It is around 55C to 60C

Zé Maurício
Sana Ullah
Mustafa M Hathal
Alfukaiki
Yuosuf Al Faraj
Raghu Can Can
Mohamed Serag
Eldeen

Robin Pv

It depends on plant and local

it's not fixed
dew point
we usually supply cooling water at
35C, so i think the max temperature
will be 40 to 45.
i think up 2 its bubble point
bubbling point

i thnk it is 30


and needs an answer

AhMed HAssan

continue

what is the MAX temperature allowable for a heat

Name

comment

answer 50c
as more than this calcium carbonate and
potassium carbonate may accumulated
AhMed HAssan
again and make fouling probs.tand
corrosion prob.
ref:Guide to process equipment book

‫رامي الحسن‬
can you give me references for production of dimethyl
ether

Name
Sana Ullah

comment
Turton,R.et al : Analysis, Synthesis and
design of Chemical Processes, 1998.
Page Number 709 to 711


and needs an answer

Nidhi Satwara
What role does the Ventury effect have on mixing
chemicals?

Name

comment

Azhar Mushtaq

it decrease the effect of pressure and
increase the mixing of chemical

Zé Maurício

speeding velocity

Muneeb Ur
Rahman

Reduces mixing time

Nidhi Satwara
How can i check the purity of Kcl?

Name
Tulio Yterbio
Fernandes Vale
Amr Waly
Zé Maurício
Er Dhaval Patel

comment
Volumetric analisys acid/base
titration vs NaOH
Constant current coulometry and ion
chromatography to subtract
bromide
Colaromatry titration


and needs an answer

Nidhi Satwara
Which chemical will you add to water to increase the
viscocity to 40 centipose?

Name

comment

Utpal Pohane

polyacrylamide & XANTHANUM GUM

Er Mayur Patil

i think..........polyacrylamide or
xanthanum gum is right ans...

Santosh Kumar
Bhavirisetti

PEG

Hasan Salamah

carpobol

Yuosuf Al Faraj

agar, but the question is what is the
fraction of agar should be added to
raise water viscosity to 40 cintypose?

Gagan Deep Kalra
Dheeraj Kumar
Yarlagadda
Er Kapil Maan

Josue Mateus
Bohn

Agar agar is rite answer
polyacrylamide
Agar agar sol is the mixture of various
carbohydrates

Agar Agar

Himanshu Sharma I thnk it is agar agar solution
Abhishek Verma

honey


and needs an answer

Zafir Imam
Esterification reaction is endothermic or exothermic?

Name
Alaa Khaled
Meetkees

Gokul Singh

Koushik Aguan

comment
exothermic
Endhothermic reaction, and
reversible, water formation take
place, it is major to remove it,
otherway potential got backward
direction
endo

Sanjay Khatri

Exothermic rxn

Moni Velasco

levemente endotermica

Ronak Raiyani

It is mainly exothermic reactions but
when the esterification generates a
cyclic ester they tend to be
endothermic reaction...!

Shraddha
Deshmukh
Jeevarathnam
Joseph

endothermic
Endothermic reaction.


and needs an answer

Zafir Imam

continue

Esterification reaction is endothermic or exothermic?

Name

comment

Nimit Vasani

Endothermic....beacuse u need heat
to evaporate water from alcoholic
group

Hiren Gohil

endothermic.

Er Dhaval Patel

Endothermic reaction

Roshan
Tembhurne

Endothermic dude

Kiran Bhatreja

Exothermic reactn

Faisal Panhwar

Endo.


and needs an answer

Trisha Sharma
can u suggest me whether chemical engg. Hv scope in
India...?

Name

comment

Usman Naseem

Yes Gutka is a Chemical, you can have
your own gutka stall at Railway
station..

Prathap Selvam

no scope..

Anil Kumar

Really no scope at all

Brijesh Rana

nt for girls......... really

Sachin Chavare

scope is what? how you take
challenge is scope...n India has very
big scope for Chemical Engineers...All
the best.

Nirali Rana

Yes...lots of scope...depends on u n ur
knowlage.

Roshan
Tembhurne

Lots of

Vishnu Soman
Kannankara

Of course yes....! but it only depends
upon u.

Mohit Sharma

Yes


and needs an answer

Abhishek Verma
What is the difference between extensive and intensive
properties ?

Name

comment

Engr Muhammad
Ali

intensive properties are independent
of mass while extensive depends
upon mass

Arthur J Shih

If you cut a system in half, quantities
that change are extensive, and
quantities that don't change are
intensive.

Ronak Raiyani

An intensive property is one whose
value does not depends on the
amount of the substance for which it
is measured.i.e:
Temp.,Sp.Gravity,Atm.Pressure etc.
while, Extensive is one that value
depends on quantity of matter in the
system.i.e.;Entropy,Enthalpy,Volume,
Gibbs Energy etc.

Er Dhaval Patel

Intensive properti independent of
mass&extensive property
bepend on mass


and needs an answer

Abhishek Verma

continue

What is the difference between extensive and intensive
properties ?

Name

comment

Taha Siddiqui

extensive property do not depends
upon mass while expensive does

Er Kapil Maan

Intensive property are bulk property
means physical properties of system
bt the extensive are interacting the
subsystem

Hasan Salamah

in. depends on mass while exdoeant
depend on mass

Vishnu Soman
Kannankara
Omar Samir

Intensive-independnt of mass

Hence all specific properties are
intensive


and needs an answer

Raghu Can Can
can u explaine about split type heat exchanger

Name

comment
the manufacturer of all types of Split Type
Steam Heat Exchanger For Rice Parboiling
Plant. it is engaged in the production and
distribution of premium quality Split Type
Steam Heat Exchanger For Rice Parboiling
Plant in the industry. These Heat Exchangers
we supply in the market is known for it high
precision performance.

In case tube leakages in heat exchanger,
Rajashekar
every tube Is repairable in your mill
Chilukamari
Cleaning system is very comfortable, open to
the framing both and cleaning the every tube
Steam goes to the multiple header instead of
standard type one header that increase
efficiency of heat exchanger & then reduces
the drying time and save the husk
In case lot of tubes leakages in Heat
exchanger, remove only leakage part and join
the new part. No need to
change total heat exchange


and needs an answer

Kavi Arasu
How much water occupy in a 1" inch s.s pipe of length 10
meter ??? How can we calculate?

Name

comment

Think of the pipe as a cylinder, volume of
cylinder is pi*r^2*h where h will be 10 m,
Muhammad
radius would be the innder radius of the 1
Usman
inch pipe by the way. Volume would be how
much water can that pipe occupy
Mohammed volume=3.14*r^2 *h
Salih
Koushik
Agarwal

5064.5 cc

Hemant
Rautela

5.064506 liters of water

Pandurang
Chate

Pi/4 X d X d X L... d is inner diameter

Zé Maurício 5 L, uff.


and needs an answer

Raghu Can Can
What is wet vacuum and dry vacuum and compare both

Name

comment

Nitin B
Sasane

vaccum containing moisture is wet vaccum.
and no misture available is dry vaccum.

Ahmed
Yehia

* i think dry vacuum that happened where
complete separation between vapors and
liquids so vacuum will occur in gas phase
100%
* on the other hand, wet vacuum happened
in gas fraction phase mean media is vapors
and some liquids
* i don't sure that

Anbarasan
Sankaran

Raghu Can
Can

Liquid particle present that is wet vacum.
There no liquid particle it is dry vacum.
Wet vacuum means in ejector if we use
steam and create vacuum means that is wet
vacuum neither we use air means that is dry
vacuum

but I don't know why they r using wet r dry
vacuum
Murthy
Meduri
Balaji

Use of steam differentiate both


and needs an answer

Dinakar Satya
why hydrogen is exception for joule thomson effect?

Name

comment

Ahmed
Mohamed
Khalil

At room temperature, all gases except
hydrogen, helium and neon cool upon
expansion by the Joule–Thomson process.
the exception for hydrogen, helium and
neon is due to (the very low inversion
temperatures) of them which is -68°C for
H2,−222 °C for helium at Atm pressure.
this make them warm up when expanded at
constant enthalpy at typical room
temperatures.

Djohan
Khairudin

When release to atmospheric pressure,it
heats up.

Molecular interaction too weak. Helium,
Neon and hydrogen are tree gases whose
Joule–Thomson inversion temperatures at a
Zé Maurício pressure of one atmosphere are very low
(e.g., about 51 K (−222 °C) for helium). Thus,
they warm up when expanded at constant
enthalpy at typical room temperatures.
Raghu Can
Can

these hydrogen and helium r
more reactive groups


and needs an answer

Dinakar Satya

continue

why hydrogen is exception for joule thomson effect?

Name

comment

Anup Ca

bcz of -ve joule thomsn coefficient....that
means :increase itz(H2)temp in throatling
process.

Ronak
Raiyani

& More cheaper than argon, krypton, xenon,
niyon etc Becoz it is noble gas.

Nirav
Gandhi

Hydrogen is not follow joul thomson effect
iir reversible

Anup Ca

Helium is an another example.

Fabio
Augusto

Hydrogen is an exception in a certain range
of P and T, but it is not the only exception.


and needs an answer

Dinakar Satya
i want to know where the distillation coulumn will be

Name

comment
It's possible, but it's not feasible. The
reason why distillation columns are vertical
is so that (1) gravity can pull the liquid phase
downward and (2) trays/packing will allow
adequate contact of the liquid and vapor
phases.

Arthur Shih

Suraj
Chaudhari

Horizontal distillation columns will not only
require two extra pumps (one for the vapor
and one for the liquid, because gravity
cannot provide the energy anymore), but it
will also need some sort of mechanism to
maximize contact between the vapor and
liquid phases. When the distillation column
is vertical, gravity and trays/packing achieves
both of these.

What....am not heard before this... Do
anybody used distillation kettle in
horizantal plane...? No its not
possible


and needs an answer

Dinakar Satya

continue

i want to know where the distillation coulumn will be

Name

comment

Arthur Shih

I also want to point out that vertical towers
also save valuable land space. One
disadvantage of vertical towers is that it
requires more piping (you need to pump the
tops product all the way down the length of
the pipe to the condensers), but the
advantages greatly outweigh the
disadvantages which is why they've become
the "standard" in the past 100 years.

Suraj
Chaudhari

What....am not heard before this... Do
anybody used distillation kettle in
horizantal plane...? No its not
possible

Er Dhaval
Patel

Itis practical not feasiable

Zé Maurício At space, rotating!
Mohammed as used in oil refineries
Salih


and needs an answer

Atul Gourh
Can we use CSTR for gaseous reactant ??

Name

comment

Nirali Rana

Generaly CSTR is used for uniform
mixing n in gasious reactant its hard
to mk perfact mixing..before mixing
day react...so PFR is more
preffrable...according to me.

Hasan Salamah

it's better to use PFR

Nafees Ahmad

yes some time, in the presence of
media (liquid)...i.e HDPE process

Er Dhaval Patel

Yatai Mike

No

Ajit Salve

Vivek Shukla

no

Rita Youfa

no, cstr 4 liq-liq or solih-liq

Antreas Koumouris
Mohamed Serag
Eldeen
Davey Uloma

we use them for slow liquid phase
rxns mostly
NOP
Ghaith Alsaidi

No


and needs an answer

Murthy Meduri Balaji
Can we use liquid DAP instead of granules? As it will
reduce the cost of granulation,drying, cooling

Name
Bujji
Fireheart

Salahuddin
Rajput

comment
ya bt
bt the cost depends on farmers
farmer lost so much of monney
its not gud product for farmer
and handling too hard
calculation is too confused for former
*Difficult to calculate (Dilution Required)
*Poor Handling
*Consume too quickly (Drawback)
*it will stay on the leafs (can harm/damage
the leaf) due to excess nitrogen
*granule release adequate amount in
particular time while liquid spills and
absorbs quickly by the soil.


and needs an answer

Saurbh Salfale
Would you please tell me what is the maximum suction
head for centrifugal pump in case of negative suction??

Name
Suraj Chaudhari
Anup Ca
Pravin Patil
Syed Shah Jehan
Gillani

Saurabh Salfale

Yatish Banakar

comment
Jit Sumon

10.30 bar

10.33 m water
10.33 m water (34 feet)
10 m
But i need an explaination over this...
I think it may related with the concept
of vapour pressure of the pumping
fluid bcoz when vapour pressure of
the pumping fluid is equal to atm.
press then cavitation will takes place
due to boiling.
For 1kg/cm2 it will give 10.33mts
head, section wil play important role
during starting of pump.. If negetive
need to give priming.
When vp is equal atm then
boiling takes place


and needs an answer

Bright Izuchukwu
xplain d principles of the heat xchanger wen fluid flows
counter currently

Name

comment

Sanjay Khatri

A device is used for exchanging or
transfering energy heat between the fluids.

if fluid in counter current den heat trnsfer
take place will be more bcoz of counter
Chiràg
current fluid directin n residence time
Mahyavanshi
between two fluid will b mor.so it creat high
ht n low require energy.
Er Rajvi Garg

heat transfer co-efficient will be more if the
flow is counter current

heat transfer will be more , contact tym is
Vibha Mishra more heat loss wiil be less and heat transfer
coefficient will be more.
Pandurang
Chate

Heat is getting transferred from hot fluid to
cold fluid. Being counter current flow, area
of heat exchanger is much lower than
cocurrent flows becuase of higher
LMTD(Log Mean Temperature Difference)

Zé Maurício

The coolant can get hotter than
the fluid cooled.


and needs an answer

Bright Izuchukwu

continue

xplain d principles of the heat xchanger wen fluid flows
counter currently

Name

comment

Mohamme heat is transferred in three different ways,
d Salih
conduction,convection,and radiation
There is more contact surface area nd contact
Suraj
time for exchange the heat and low exotherm
Chaudhari
nd optimum operational cost

Sha Geck

@mohammed salih: heat exchangers
exchange heat between the process fluid and
cooling fluid by means of conduction and
convection..
Not by radiation..!


and needs an answer

Dinakar Stya
how nuclear fusion and fission will takes place at a time in
hydrogen bomb?

Name

comment

Mohamed
Ahmed
Fouad

The energy required for nuclear fusion
comes from uranium splits which results in
fussion and release a large amount of
energy. So, in hydrogen bomb nuclear
fission of uranium first takes place then
nuclear fusion of Deuterium and tritium
takes place.

Nidhi Satwara
uses of vinyl sulphone ester ?

Name
Er Dhaval
Patel

comment
It is used as intermideate in dyes stuf
industry.


and needs an answer


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2013

I am chemical engineer magazine 6 2013

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