This impeller. In the piping organization used the centrifugal

This report is to provide an impression on centrifugal pumps in
overall and particularly the application of the centrifugal pump in the oil
industry. There is an extensive series of pumps accessible but as the radial
pump is by distant the greatest productive fellow of the pump family so this report
will focus on them. It will first describe the general introduction about
centrifugal pumps, principal of centrifugal pump, and its kinds of building,
which bandwidth of pressures and stream degrees are existing and how to select
the right pump for an exact application. Also describe the components of the
centrifugal pump, such as impeller, shaft, inlet and outlet, impeller seals and
casing. Later sections agreement with classic difficulties when using centrifugal
pumps such as corrosion and cavitation’s.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2. Aim:

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Aims of this report are:

·        
Introduction about the centrifugal pump and how it
work.

·        
Identify the types of centrifugal pump.

·        
What are applications of the centrifugal pump in oil industry?

The importance of the centrifugal pump is used to
transfer rotational kinetic energy for increasing the head of fluid flow and
the hydrodynamic energy. 

3. Introduction:

The centrifugal pump was first invented in 1689 by
physicist Denis Papin, and today in the round of world the greatest type of
pumps that secondhand everywhere in world is centrifugal pump as show in figure
1 (Skovgaard, 2004). A centrifugal pump
is propeller energetic pump and for growing the pressure of the liquid in the centrifugal pump uses
rotating impeller. In the piping organization used the centrifugal pump for
moving the liquids through the pipe. In the centrifugal pump first the liquid
goes into the pump impeller along or close to the rotating axis and impeller is
quickened liquids that enter the pump, streaming radially outward into volute
chamber, from where it exists into downstream piping system. For large release
through littler heads used centrifugal pump.                             

Like most kind of pumps, a centrifugal pump change
over the mechanical energy from engine to energy for moving liquid, for liquid
motion in the centrifugal pump some of the energy will be the kinetic energy, also
some of the energy will be potential energy, a higher level spoken by the
liquid weight or by lifting liquid against gravity.

Figure 1 (Centrifugal pump)

3.1 Principle of the Centrifugal Pump:

When the centrifugal pump in the operation, from the
pump inlet increasing the liquid weight to it is outlet is made, through the
system or plant, the pressure difference drives the liquid. In the centrifugal
pump the mechanical energy was transferred between the motor and liquid, when
the energy was transferred from the motor to the fluid through rotating
impeller, this is cause to create an increase in pressure.

The liquid streams from the inlet to the impeller
center and out along it is cutting edges, increasing the velocity of fluid by
centrifugal force and this result that kinetic energy is transfer to the
pressure. As show in figure 2 an example of the fluid path through centrifugal
pump.

Figure 2 Fluid path through centrifugal
pump

 

3.2 Application of Centrifugal Pump in Oil industry:

There are many application of centrifugal pump in oil
industry such as in the circulation of mud in the drilling rig during the
drilling process, and in the transforming the oil in the pipeline system. In
the mud circuit on drilling rig, the mud pump is the heart of the process of
circulation of mud because without the mud pump, it is very difficult for
circulated the mud. For circulate the mud needed high pressure, and the mud is
pumped through the standpipe, hose, swivel, and goes to the Kelly, drill pipe,
bit and return to the surface. At the surface there are many locations in the
mud circuit process can found the centrifugal pump like degasser, desander, and
mud cleaner as well as the mud pump.

In pipeline application, using the pipeline for
transport the hydrocarbon such as the oil and gas for over long distance. For
this distance needed very high pressure, first the oil storage in the tank at
the beginning to ensure a continue flow through the pipeline system, by using
the centrifugal pump the oil is pumped through the piping system in high
pressure.    

 

3.3 Components of Centrifugal Pump:

The main components of centrifugal pump are the
impeller, the casing, shaft, inlet, and outlet, and impeller seals as show on figure
3 that show the general components of centrifugal pump. Which described some
components below.

Figure 3 General components of
Centrifugal Pump

 

3.3.1 Impeller     

The energy is transfer to the fluid in centrifugal
pump by the blades of the rotating impeller, for transferring the energy needed
to increasing the pressure and velocity of the fluid. Essential part of the
centrifugal pump is impeller, there are having three types of impeller in
centrifugal pump and each of the types using for specific application. Types of
impeller are open, enclosed and semi open impeller as show on figure 4.

The simplest type of the impeller is open
impeller and at the same diameter of each type of impeller the open impeller is
lighter than all types of impeller, open impeller consists of the blades
attached to the hub. Semi open impeller is usually located at the back of
impeller and it is between the open and enclosed impeller, the semi open
impeller is usually operates at higher efficiency than the enclosed impeller
and it is constructed with only one shroud.  
    

       

      

 

 

 

Figure 4 types of impeller

3.3.2 Casing:

The casing in the centrifugal pump is the force to the
fluid discharge from the centrifugal pump and change the speed of the fluid in
to pressure. The casing houses the gap gathering and it is form harm. The
design of the casing is important for reducing the friction losses in the
centrifugal pump, the shaft bearing is supported by the casing, takes the
radial power of the pivoting impeller and hub loads caused by the weight push
irregularity.  

There are having two types of casing, types of casing
are single-volute casing and double-volute casing as show in figure 5. The
difference between both types of casing is just that the double volute has a
guide vane. At the optimum efficiency point, in the volute the single-volute
casing of the casing is characterized by symmetric pressure. In the
single-volute casing the radial forces is zero, this pressure that around the
impeller is not regular and always the radial force is present.                                             

Figure 5 Types of Casing

 

3.3.3 Shaft:

The shaft is an electrical motor in most cases and it
can be a gas turbine, it is an association between the impeller and drive unit
in the centrifugal pump. A radial force caused that the shaft is for the most
part charged, radial forces caused by an axial force and unbalance pressure
forces in the spring casing, and the axial force is because of the weight difference
between front and posterior of the impeller.

Shafts are made of the carbon steel in the most of
pumps, the bearings and seals are supported by the shaft because there are
several cracks. In the casing the most important is clearance and surface
quality to guarantee right situating of the shaft in the areas of the bearing’s,
but at the area of the seals are different than bearing, the difference is that
the especially the surface quality is critical to guarantee an adequate of the
shaft. “In shaft design it is also important to avoid small radiuses at
cranks to minimize stress in these areas which are susceptible for fatigue”.        

3.3.4 Impeller seals:

When the pump is in operating, the path of the flow of
fluid will be occur in the gap between the rotating impeller and stationary
pump housing. The rate of path of the fluid flow in the centrifugal pump is
depends mainly on the design of the gap and the impeller pressure rise. Through
the gap, the path of fluid flow returns to the impeller eye, the impeller needs
to pump both of the hole streams of fluid flow and the fluid through the pump
from inlet flange to the outlet flange as show in figure 6. The impeller seal
is mounted for minimize hole stream of fluid.  

The impeller seal can made in many designs and many
material blends, in the pump housing, the impeller seal is ordinarily turned
straightforwardly. Impeller seals can likewise be made with floating seal
rings. Moreover, there are a scope of sealing’s with elastic rings specifically
well-suited for taking care of fluid with grating particles, for example, sand.
 

Figure 6 path of flow through the gap
 

 

3.3.5 Volute casing, diffuser and outlet
flange:

The volute casing accumulates the liquid from the impeller and
indications into the outlet flange. The volute casing
changes the dynamic pressure increase in the impeller to static
pressure. The velocity is regularly condensed when the cross-sectional area of the liquid stream is improved. This conversion
is called velocity diffusion. An example of diffusion is when the
liquid velocity in a pipe is condensed because
of the changeover from a small cross-sectional area to a large
cross-sectional area. The volute casing involves of three main mechanisms: Ring
diffusor, volute and outlet diffusor. An energy translation between velocity
and pressure arises in each of the three mechanisms. The primary ring diffusor
role is to attendant the liquid from the impeller to the volute. The
cross-section area in the ring diffusor is improved because of the rise in
diameter from the impeller to the volute. Knife-edges can be located in the
ring diffusor to rise the diffusion.

 

 

 

 

3.4
Problems at Centrifugal pump:

A main problematic at centrifugal pumps is, similar at all wild
moving fragments in a liquid, cavitation. Other problems obtain solid handling,
abrasives and corrosives as well as leakage. Most mistakes during pump process
can be circumvented by choosing a quality pump designed for the plan and
acceptable conservation.

3.4.1 Cavitation:

Cavitation happens when the static pressure in a liquid is lesser
than the liquids vapor pressure, typically affected by great velocities. Owed
to Bernoulli’s law, static pressure falls when velocity is growing. If this occurs,
the liquid locally begins boiling and customs gas bubbles which want more interplanetary
than the liquid would yield. In a centrifugal pumps impeller, the bubbles are affecting
to an area of reducing pressure. If the pressure now surpasses the vapor
pressure, the gas condensates at the bubble’s inside surface and so failure quickly.
This collapse of gas bubbles reasons high, briefly pressure variations of up to
a limited 1000bar. As the liquid streams from higher to lower pressure, this stream
reasons a jet of the close liquid, which may sensation the surface. These great
energy micro?jets reason great
compressive anxiety failing the solid.

Lastly, crater?shaped
distortions and fleabags known as cavitation pitting occur. Other causes for
cavitation can be an increase of liquid temperature, a low pressure at the pressure
cross or a rise of distribution height. Cavitation’s in centrifugal pumps mostly
happen at the impeller leading edges but likewise at the impeller vane, costume
rings and push balance fleabags as show in figure 7. To escape cavitation, it
is essential to deliver enough NPSH and to save liquid temperature low. Great liquid
temperatures can happen if the pump is on to save the pressure up but no liquid
is occupied available.  The damage of
cavitation to the impeller and additional fragments of the pump is important.

Figure 7 region of impeller cavitation

 

3.4.2 Solids and slurry handling:

Once expectant solids in the liquid or selling through slurries, it
is significant to choice a pump that is planned for this submission. On the
additional pointer cross, slurry pumps are much classier than a standard water
pump, so the judgment is not that relaxed. As there is a very extensive
assortment of slurries it is valuable to division them into three groups,
light, medium and heavy slurries. To deliver a pump that can be secondhand with
slurries, different design structures must be made. Slurry pumps can be
prepared with example heavier wear pieces, larger impellers, special material
and semi?volute or
concentric casing. All these structures cover pump lifetime but likewise since
drawbacks similar higher initial costs, higher weight or less efficiency.
Slurry pumps can be divided into two main groups, rubber lined and hard metal
pumps.

3.4.3 Corrosion:

Corrosion is contravention down of important properties in a
material owing to chemical or electrochemical responses with its environments.
As there is an extensive range of pump applications inside the chemical
industry, including the petroleum industry, treatment oil and gas up to great
violent acids it is significant to deliver pumps that can be worked below these
hard situations. There are some types of corrosion and many issues it be
contingent on, like liquid temperature, contained elements and pH?value. Most common and dangerous corrosion in pumps is the so
called unchanging corrosion. This is the general outbreak of a corrosive liquid
on a metal. The chemical responses between liquid and metal surface principal
to unchanging metal damage on the moisturized surface, known as corrosive wear.
To lessen corrosive wear it is significant to select a strong pump material.

3.5 General Design of the Centrifugal Pump:

It is not a hard job to project a centrifugal pump, still,
designing the right pump for a definite submission connected to a definite
industry and facility needs a general information of hydraulics. Likewise essential
is skill with manufacturing conditions, end operators, and servicer’s singular wants
and several years of applied skill in engineering and selling. The variables
that happen for pump wants are so frequent that the design of the right pump in
the right facility is a compound plan. There is no such creation as the
“universal pump.” As a sample, let us take a pump that is essential
to yield 500 GPM and 200-ft head, spinning at 2 or 4 limit rapidity. In any or
all industries this hydraulic condition happens; nevertheless, the mechanical conditions
are totally unlike for each and every industry. For example, the kind of pumps secondhand
in the tissue and newspaper industry are totally unlike from pumps secondhand
in the petroleum industry, petrochemical industry, or chemical industry. Therefore,
the pump essential to deliver 500 GPM and 200-ft head, will be unlike for every
of the following applications are Slurry, Boiler feed, Pipeline, Nuclear, Municipal,
Agricultural, Marine.  

 

 

4.
Discussion and Result:

In the lab, testing the centrifugal pump in series and parallel.
First testing the centrifugal pump in series, driving your centrifugal pumps in series, or associated
sideways a single line, will let you improve the crown from each composed and see
your high head, low flow system wants. This is since the fluid pressure rises
as the incessant stream permits complete all pumps, much like how a multi-stage
pump works.  For case, we have two pumps of the centrifugal pump, they are
in series,     and the flow rate of the
fluid will be double than using one pump of centrifugal pump as show in the
figure 8. That the head flow of the flow of two pumps in series is double than
the single pump. 

If the centrifugal pump in series and
with controls that provide high pressure, in conditions where a great, constant
pressure is essential, deliberate addition rapidity controller to the last pump
in a series. This shape realizes the great pressure that is wanted, while charge
a small flow, since the fixed-speed pump feeds into the speed-controlled pump,
which regulates its production with a pressure spreader to improve only sufficient
skull to keep a constant pressure.

figure 8 compered the head flow between two
pumps in series and signle pump

Driving pumps in the parallel, or linked
toward selected amount of streak twigs therefore that every levers a parting of
stream, drive assistance you range a low head, high flow working fact that an only
pump cannot source. Moreover, this organization formation provides you elasticity
by agreeing the substituting of parallel pumps on or off in instruction to correct
to adjustable flow situations.

In suitcases where a mutable stream
and great effectiveness is necessary, contemplate addition rapidity switch to every
pumps to complete respectable presentation and to work pumps earlier to their greatest
effectiveness point. In this formation, two situations can happen: one pump container
completely run while the other increases stream when required, or together
pumps container run at condensed rapidity and regulate as required.

“Running a pump at full speed causes
you to move past the BEP on the right side, lowering efficiency and causing
potential issues.  With two controlled pumps operating at partial
capacity, you can still have control over the flow while running each pump
closer or to the left of its BEP, resulting in a more efficient
operation.  Overall, this configuration offers a wide range of operating
conditions and opportunities for better efficiencies in order to meet your
variable flow needs”