This report is to provide an impression on centrifugal pumps inoverall and particularly the application of the centrifugal pump in the oilindustry. There is an extensive series of pumps accessible but as the radialpump is by distant the greatest productive fellow of the pump family so this reportwill focus on them. It will first describe the general introduction aboutcentrifugal pumps, principal of centrifugal pump, and its kinds of building,which bandwidth of pressures and stream degrees are existing and how to selectthe right pump for an exact application. Also describe the components of thecentrifugal pump, such as impeller, shaft, inlet and outlet, impeller seals andcasing.
Later sections agreement with classic difficulties when using centrifugalpumps such as corrosion and cavitation’s. 2. Aim:Aims of this report are:· Introduction about the centrifugal pump and how itwork.
· Identify the types of centrifugal pump.· What are applications of the centrifugal pump in oil industry?The importance of the centrifugal pump is used totransfer rotational kinetic energy for increasing the head of fluid flow andthe hydrodynamic energy. 3. Introduction:The centrifugal pump was first invented in 1689 byphysicist Denis Papin, and today in the round of world the most kind of pumpsthat used around the world is centrifugal pump as show in figure 1 (Skovgaard, 2004). A centrifugal pumpis rotor dynamic pump and for increasing the pressure of the fluid in the centrifugal pumpuses rotating impeller. In the piping system used the centrifugal pump formoving the liquids through the pipe.
In the centrifugal pump first the liquidgoes into the pump impeller along or close to the rotating axis and impeller isquickened liquids that enter the pump, streaming radially outward into volutechamber, from where it exists into downstream piping system. For large releasethrough littler heads used centrifugal pump. Like most kind of pumps, a centrifugal pump changeover the mechanical energy from engine to energy for moving liquid, for liquidmotion in the centrifugal pump some of the energy will be the kinetic energy, alsosome of the energy will be potential energy, a higher level spoken by theliquid 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 thepump inlet increasing the liquid weight to it is outlet is made, through thesystem or plant, the pressure difference drives the liquid. In the centrifugalpump the mechanical energy was transferred between the motor and liquid, whenthe energy was transferred from the motor to the fluid through rotatingimpeller, this is cause to create an increase in pressure.The liquid streams from the inlet to the impellercenter and out along it is cutting edges, increasing the velocity of fluid bycentrifugal force and this result that kinetic energy is transfer to thepressure. As show in figure 2 an example of the fluid path through centrifugalpump. Figure 2 Fluid path through centrifugal pump 3.2 Application of Centrifugal Pump in Oil industry:There are many application of centrifugal pump in oilindustry such as in the circulation of mud in the drilling rig during thedrilling process, and in the transforming the oil in the pipeline system. Inthe mud circuit on drilling rig, the mud pump is the heart of the process ofcirculation of mud because without the mud pump, it is very difficult forcirculated the mud.
For circulate the mud needed high pressure, and the mud ispumped 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 themud circuit process can found the centrifugal pump like degasser, desander, andmud cleaner as well as the mud pump. In pipeline application, using the pipeline fortransport the hydrocarbon such as the oil and gas for over long distance.
Forthis distance needed very high pressure, first the oil storage in the tank atthe beginning to ensure a continue flow through the pipeline system, by usingthe centrifugal pump the oil is pumped through the piping system in highpressure. 3.3 Components of Centrifugal Pump:The main components of centrifugal pump are theimpeller, the casing, shaft, inlet, and outlet, and impeller seals as show on figure3 that show the general components of centrifugal pump. Which described somecomponents below. Figure 3 General components of Centrifugal Pump 3.3.1 Impeller The energy is transfer to the fluid in centrifugalpump by the blades of the rotating impeller, for transferring the energy neededto increasing the pressure and velocity of the fluid.
Essential part of thecentrifugal pump is impeller, there are having three types of impeller incentrifugal pump and each of the types using for specific application. Types ofimpeller are open, enclosed and semi open impeller as show on figure 4. The simplest type of the impeller is openimpeller and at the same diameter of each type of impeller the open impeller islighter than all types of impeller, open impeller consists of the bladesattached to the hub.
Semi open impeller is usually located at the back ofimpeller and it is between the open and enclosed impeller, the semi openimpeller is usually operates at higher efficiency than the enclosed impellerand it is constructed with only one shroud. Figure 4 types of impeller3.3.2 Casing:The casing in the centrifugal pump is the force to thefluid discharge from the centrifugal pump and change the speed of the fluid into pressure. The casing houses the gap gathering and it is form harm. Thedesign of the casing is important for reducing the friction losses in thecentrifugal pump, the shaft bearing is supported by the casing, takes theradial power of the pivoting impeller and hub loads caused by the weight pushirregularity.
There are having two types of casing, types of casingare single-volute casing and double-volute casing as show in figure 5. Thedifference between both types of casing is just that the double volute has aguide vane. At the optimum efficiency point, in the volute the single-volutecasing of the casing is characterized by symmetric pressure. In thesingle-volute casing the radial forces is zero, this pressure that around theimpeller 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 itcan be a gas turbine, it is an association between the impeller and drive unitin the centrifugal pump. A radial force caused that the shaft is for the mostpart charged, radial forces caused by an axial force and unbalance pressureforces in the spring casing, and the axial force is because of the weight differencebetween front and posterior of the impeller. Shafts are made of the carbon steel in the most ofpumps, the bearings and seals are supported by the shaft because there areseveral cracks. In the casing the most important is clearance and surfacequality 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 thatthe especially the surface quality is critical to guarantee an adequate of theshaft.
“In shaft design it is also important to avoid small radiuses atcranks 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 offluid will be occur in the gap between the rotating impeller and stationarypump housing.
The rate of path of the fluid flow in the centrifugal pump isdepends mainly on the design of the gap and the impeller pressure rise. Throughthe gap, the path of fluid flow returns to the impeller eye, the impeller needsto pump both of the hole streams of fluid flow and the fluid through the pumpfrom inlet flange to the outlet flange as show in figure 6. The impeller sealis mounted for minimize hole stream of fluid. The impeller seal can made in many designs and manymaterial blends, in the pump housing, the impeller seal is ordinarily turnedstraightforwardly. Impeller seals can likewise be made with floating sealrings.
Moreover, there are a scope of sealing’s with elastic rings specificallywell-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 outletflange:The volute casing accumulates the liquid from the impeller andindications into the outlet flange. The volute casingchanges the dynamic pressure increase in the impeller to staticpressure. The velocity is regularly condensed when the cross-sectional area of the liquid stream is improved.
This conversionis called velocity diffusion. An example of diffusion is when theliquid velocity in a pipe is condensed becauseof the changeover from a small cross-sectional area to a largecross-sectional area. The volute casing involves of three main mechanisms: Ringdiffusor, volute and outlet diffusor. An energy translation between velocityand pressure arises in each of the three mechanisms. The primary ring diffusorrole is to attendant the liquid from the impeller to the volute. Thecross-section area in the ring diffusor is improved because of the rise indiameter from the impeller to the volute.
Knife-edges can be located in thering diffusor to rise the diffusion. 3.4Problems at Centrifugal pump:A main problematic at centrifugal pumps is, similar at all wildmoving fragments in a liquid, cavitation. Other problems obtain solid handling,abrasives and corrosives as well as leakage.
Most mistakes during pump processcan be circumvented by choosing a quality pump designed for the plan andacceptable conservation.3.4.1 Cavitation:Cavitation happens when the static pressure in a liquid is lesserthan the liquids vapor pressure, typically affected by great velocities.
Owedto 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 interplanetarythan the liquid would yield. In a centrifugal pumps impeller, the bubbles are affectingto an area of reducing pressure.
If the pressure now surpasses the vaporpressure, 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 toa limited 1000bar. As the liquid streams from higher to lower pressure, this streamreasons a jet of the close liquid, which may sensation the surface. These greatenergy micro?jets reason greatcompressive anxiety failing the solid. Lastly, crater?shapeddistortions and fleabags known as cavitation pitting occur. Other causes forcavitation can be an increase of liquid temperature, a low pressure at the pressurecross or a rise of distribution height. Cavitation’s in centrifugal pumps mostlyhappen at the impeller leading edges but likewise at the impeller vane, costumerings and push balance fleabags as show in figure 7.
To escape cavitation, itis essential to deliver enough NPSH and to save liquid temperature low. Great liquidtemperatures can happen if the pump is on to save the pressure up but no liquidis occupied available. The damage ofcavitation 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, itis significant to choice a pump that is planned for this submission. On theadditional pointer cross, slurry pumps are much classier than a standard waterpump, so the judgment is not that relaxed. As there is a very extensiveassortment of slurries it is valuable to division them into three groups,light, medium and heavy slurries.
To deliver a pump that can be secondhand withslurries, different design structures must be made. Slurry pumps can beprepared with example heavier wear pieces, larger impellers, special materialand semi?volute orconcentric casing. All these structures cover pump lifetime but likewise sincedrawbacks similar higher initial costs, higher weight or less efficiency.Slurry pumps can be divided into two main groups, rubber lined and hard metalpumps. 3.4.
3 Corrosion:Corrosion is contravention down of important properties in amaterial owing to chemical or electrochemical responses with its environments.As there is an extensive range of pump applications inside the chemicalindustry, including the petroleum industry, treatment oil and gas up to greatviolent acids it is significant to deliver pumps that can be worked below thesehard situations. There are some types of corrosion and many issues it becontingent on, like liquid temperature, contained elements and pH?value.
Most common and dangerous corrosion in pumps is the socalled unchanging corrosion. This is the general outbreak of a corrosive liquidon a metal. The chemical responses between liquid and metal surface principalto 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 definiteindustry and facility needs a general information of hydraulics.
Likewise essentialis skill with manufacturing conditions, end operators, and servicer’s singular wantsand several years of applied skill in engineering and selling. The variablesthat happen for pump wants are so frequent that the design of the right pump inthe 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 essentialto yield 500 GPM and 200-ft head, spinning at 2 or 4 limit rapidity.
In any orall industries this hydraulic condition happens; nevertheless, the mechanical conditionsare totally unlike for each and every industry. For example, the kind of pumps secondhandin the tissue and newspaper industry are totally unlike from pumps secondhandin the petroleum industry, petrochemical industry, or chemical industry. Therefore,the pump essential to deliver 500 GPM and 200-ft head, will be unlike for everyof the following applications are Slurry, Boiler feed, Pipeline, Nuclear, Municipal,Agricultural, Marine. 4. Discussionand Result:In the lab, testing the centrifugal pump in series and parallel.
Firsttesting the centrifugal pump in series, driving your centrifugal pumps in series, or associated sideways asingle line, will let you improve the crown from each composed and see yourhigh head, low flow system wants. This is since the fluid pressure rises as theincessant stream permits complete all pumps, much like how a multi-stage pumpworks. For case, we have two pumps of the centrifugal pump, they are inseries, andthe flow rate of the fluid will be double than using one pump of centrifugalpump as show in the figure 8. That the head flow of the flow of two pumps in seriesis double than the single pump. If the centrifugal pump in series and withcontrols that provide high pressure, in conditions where a great, constantpressure is essential, deliberate addition rapidity controller to the last pumpin a series. This shape realizes the great pressure that is wanted, while chargea small flow, since the fixed-speed pump feeds into the speed-controlled pump,which regulates its production with a pressure spreader to improve only sufficientskull to keep a constant pressure.
figure 8 compered the head flow between two pumps in series and signle pump