Successfully reported this slideshow.
We use your LinkedIn profile and activity data to personalize ads and to show you more relevant ads. You can change your ad preferences anytime.

Pump system

89 views

Published on

Design and Engineering for Energy Efficient Pumping System

Published in: Engineering
  • Be the first to comment

Pump system

  1. 1. Pump Operating System It is important to note that a pump station and pumping system have many important design considerations withaviewto focuson aspectsthat directly contribute to its energy efficiency and life cycle costing. While on this, station loss in a pump system is considered to be a very important key factor in computing pump parameters for selecting suitable pump(s) for the system. It is experienced that in many cases, Engineers as an act of conservativeness consider safety factors while designing pumping Station resulting adverse impact to the operating system. 1. Safety Factor: Unnecessary safety factor drastically change the pattern of system curve affects selectionof pumpswhich are tooperated awayfrom BEP resultinglossof energyinthe system. Thisaspect triggersdispute amongstthe buyerandseller where buyer wrongly interpret pump parameters to the seller and install over or undersized pumps in the system. The Hazen-Williams equation is assumed to be relatively accurate for piping systems with Reynolds Numbers above 105 (turbulent flow). 1 ft (foot) = 0.3048 m 1 in (inch) = 25.4 mm 1 gal (US)/min =6.30888x10-5 m3/s = 0.227 m3/h = 0.0631 dm3(liter)/s = 2.228x10-3 ft3/s = 0.1337 ft3/min = 0.8327 Imperial gal (UK)/min 2. SelectionofPump: It mustbe notedthat the patternof pumppowercurve has risingtrend with the flow capacity in case of Radial Type Centrifugal pumps with low specific speed range. Therefore,wrongselectionof oversized pumps will not only attract higher power but will limit the range of operation that not fulfill the requirement of operation covering minimum and maximumwaterlevel of the system where may reach the cut off point of operating condition because of NPSH factor.
  2. 2. 3. Site Condition: Site demography is of key importance to draw up actual piping layout for the system where inmanycasesit has been noticed that there are significant difference between the design layout and physical installation that adversely impact pumping system operating condition. Let us realize that pump sizing and dimensions are the key factors in designing the pump house layout while its of importance for Design Team consisting of Civil, Electro- Mechanical Engineers to consult amongst themselves in arriving at the correct design parameters for attaining desired plant efficiency. 4. Type of Pump Station: Pumping stations are designed according to the application and site conditionsuchas pumpingwaterfroma WaterSource such as River, Canal, Lake, Reservoir etc. Where Horizontal Centrifugal orVertical Turbine orMixedFlow Pumpstationsare designed with Intake ForebayorChannel forwaterintake intothe pumpingstationtakinginto account various design conditions such as intake water flow velocity, spacing of pumps inside or pump house consideringmultiple pumps for parallel operation in order to maintain flexibility according to the ongoing demand and provision for future demand as well. Channel mountedInclined pumps are also installed at the river bed in some installation those are generallydrivenbyDiesel orElectricdrive throughangulargeardrive andnecessarythrough bearing keeping axial thrust component in mind. Horizontal Centrifugal Pumps of Radial type of axially split types are also installed in the said applicationwithsuctionpipesdrawingwaterfromthe watersource where NPSH condition is of prime importance in order to ensure that pump does not suffer due to cavitation at the minimum water level conditions. In some extreme cases Vacuum pump sets are put in the system prior to starting of the main intake pumps certainly at an extra cost to the project because of certain site constraints. The river flow varies during the year but the hydro installation is designed to take a constant flow.If the channel overflows there will be serious damage to the surroundings. Weir is put in the system at the upstream of the forebay in order to ensure correct flow to the pumping channel regardlessof river isinlow or in highflow.The intake structure isdesignedtoregulate the flow to within reasonable limits when the river is in high flow. Further regulation of the channel flow is provided by the spillways. A Sump Model Study at the design stage is of
  3. 3. significant importance prior to finalization of design in order to ensure efficient operating system. De-silting is a regular process which at times are neglected affecting pumping system from smooth pumping operation and damage to pumps due to unforeseen variation water flow to the system with sand particle those are prone to cause abrasion damage to the pumps. Accordingto the experience itisnoticedthatpumpsattainlongerlife withmaterial combination such as 2 TO 2.5% Nickel Cast Iron Casing with SS to CA15 Impeller, SS410/416 Shaft with SS304 Sleeveswhere CA15Material hasan unique qualitytowithstandbothcorrosive andapplication.
  4. 4. 5. Variable Frequency Drive: VFD has its significance in the pumping system in order to ensure Head-Flow Characteristic through speed variation according to the demand of the system without disturbing or wasting energy due to throttling method in varying the system head characteristics. 6. Surge Analysis: Surges in pipelines carrying liquids are usually caused by opening, closing or regulatingvalvesorpumpsstartingandstopping.These surges, also called hydraulic transients may range inimportance from a slightpressure or velocity change to sufficiently high pressure or vacuum to rupture the piping system, to damage pumping equipment and cause extensive shutdowntime.Waterhammer,aresultof hydraulictransients,will occur when the total surge pressure exceedsapproximately twice the value of the static pressure in the system when the fluid is at rest. Surge protection analysis will be performed on critical sections of the piping systemtoverifydesignandsurge control equipmentselection.If excess transient pressures are predicted by the analysis, design and mechanical equipment application will be modified. Hydraulicsurge control is a specialized field. If a detailed surge protection study is required, it should be provided by engineers or consulting engineering firms specialized in this field. Detailed pipeline surge analysis by an expert should be considered.
  5. 5. 7. Starting Characteristics of Pumps:In normal casespumpsare recommended to start from crack openconditionexpectforhighspecificspeedpumps where break away torque of drive motors have 20% of FLT inorderfor smoothstartingof pumpswithoutstalling.Inthe event of extreme conditions of discharge valve failure of pump in parallel operation with corresponding Non Reverse Ratchet failure in case of Vertical Pumps, pump is required to start from reverse flow condition where the drive motors are required to start from such extreme condition. In such cases Double Cage Squirrel type or slip ring motors are recommended with higher starting torque characteristics that can attain to the full load speed within the desired time without stalling and overheating.
  6. 6. 8. Pump Motor Control System: Whenit comesto buildanenergy efficient pumping system, the choice of the appropriate motorcontrol systemandInstrumentation Panel is crucial in order to measure and control Hydraulic, Thermal and Electrical Parameters for smooth and uninterrupted operation of the system. However, it is also recommended according to experience that control system is designed with a pragmatic view so that the system is not prone to unnecessarytrippingdue insignificantconditionsthataffectsthe continued running of the pumping system. For detailed study, design and Turnkey solution in pumping system, all are welcome to contact: Deepen Mallick Mobile: +91-9874673733; Email: deepen@amalint.com; mallick.deepen@gamil.com

×