1 / 41

CENTRIFUGAL COMPRESSORS

CENTRIFUGAL COMPRESSORS. Fabrizio Tani October 23rd 2001. GE-NP Proprietary Information. g. GEPS Oil & Gas. GE Overview. g. GEPS Oil & Gas. The GE Portfolio of Businesses. Aircraft Engines Appliances Capital Services Industrial Systems Lighting Medical Systems Plastics

vian
Download Presentation

CENTRIFUGAL COMPRESSORS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. CENTRIFUGAL COMPRESSORS Fabrizio Tani October 23rd 2001 GE-NP Proprietary Information

  2. g GEPS Oil & Gas GE Overview

  3. g GEPS Oil & Gas The GE Portfolio of Businesses Aircraft Engines Appliances Capital Services Industrial Systems Lighting Medical Systems Plastics Power Systems Transportation Systems NBC Distinct … Diverse … Global

  4. g 130 12.7 112 100 10.7 91 9.3 8.2 1997 1998 1999 2000 1997 1998 1999 2000 GEPS Oil & Gas GE Results ($B) Revenues Earnings Volume Increase as Result of Customer Satisfaction

  5. g GEPS Oil & Gas Product & Services Leadership Rotoflow Center of Excellence for... Thermodyn • TurboExpanders • Low to Medium Pressure Compressors • Low to Medium Power Steam Turbines Nuovo Pignone • Compressors • Gas Turbines • Steam Turbines • Reactors • Air-Coolers • Pumps - Valves • Metering Systems • Fuel Dispensers Gemini • High Speed Recips. A-C Compressor • Screw Compressors CONMEC Odessa • Multi-VendorCompressor Services • Multi-Vendor GT Svs

  6. GAS GAS Suction Pressure = Ps Suction Temperature = Ts Suction Velocity = Us Discharge Pressure = Pd Discharge Temperature = Td Discharge Velocity = Ud WHAT IS A COMPRESSOR? PRESSURE RATIO COMPRESSOR Compressor = Black Box to increase Gas Pressure

  7. EFFICIENCY • Ratio advantages / price OR • Ratio cost in perfect world / cost in real world

  8. ADIABATIC PROCESS: No exchange heat with external environment First law of thermodynamics Adiabatic Process : Absorbed Power (P) = Specific Work (W) x Gas Flow (G)

  9. ISENTROPIC PROCESS • same suction conditions Ps,Ts • same discharge pressure Pd • lower discharge temperature Tis A further hypothesis: NO LOSSES The isentropic process associated to the real adiabatic process has: Isentropic Process = All Energy to Compress Gas

  10. Specific Work: ISENTROPIC EFFICIENCY The ratio of isentropic work to the total adsorbed energy “The ratio between what we would pay to obtain a needed result in a perfect world and what we pay to obtain the same result in the real world” Isentropic efficiency is a function of pressure ratio

  11. TOTAL ADSORBED ENERGY minus ISENTROPIC WORK LOSSES Losses always associated to the real process No analytical way to describe the real process point by point

  12. Solution to control the process • isoentrope from suction conditions to the final discharge pressure WORK INPUT ONLY • isobar at constant discharge pressure to achieve the discharge temperature HEAT INPUT ONLY

  13. For each step the isentropic work POLYTROPIC WORK: The sum of all the isentropic works step by step We define the equation: e is the constant for which the path passes through suction and discharge conditions and the isentropic efficiency of each step The equation define the theoretical process called POLYTROPE

  14. POLYTROPIC EFFICIENCY The ratio of polytropic work to the total adsorbed energy “The ratio between the advantage we can obtain with the use of a certain tool and the price we have to pay” For a perfect gas Polytropic efficiency is not pressure ratio dependant

  15. DIFFERENT POINTS OF VIEW CUSTOMER NEEDS • A way to compare compressor of different manufacturers for the same service • A method to check the performance of the machine at site Verify the performance MANUFACTURER NEEDS • Define a relationship between the performance and the geometry Achieve the performance

  16. A WORKING IMPELLER Normally the tangential component of C1 is negligible

  17. The radial component of gas velocity is associated to the flow Multiply the inlet radial velocity by the area at inlet to obtain the volume flow at impeller suction The tangential component of gas velocity is associated to the work made on the fluid Euler equation

  18. EULER EQUATION The energy exchanged, per unit of weight of fluid, between impeller outlet and inlet by its angular speed In the hypothesis that C1u is negligible

  19. EULER EQUATION Based on mechanical principles FIRST LAW EQUATION Based on thermal quantities W is the same!

  20. DIMENSIONAL ANALYSIS To predict performance we need non dimensional coefficients representing a physical phenomenon that are: • independent of the actual size of the machine • independent of the actual impellers speed • independent of gas characteristics The non dimensional coefficients are: • Inlet Flow Coefficient • Outlet Flow Coefficient • Peripheral Mach Number • Reynolds Number • Head Coefficient Results of experimental works carried out on models of the real stages

  21. INLET FLOW COEFFICIENT The ratio between the radial component of the gas velocity at inlet and impeller speed in the same point 1 identifies gas angles at inlet OUTLET FLOW COEFFICIENT The ratio between the radial component of the gas velocity at outlet and impeller peripheral speed A different form

  22. PERIPHERAL MACH NUMBER The ratio of impeller peripheral speed to the velocity of sound at impeller inlet: •  gas suction density • u impeller peripheral speed • b impeller exit width •  dynamic viscosity A measure of gas compressibility REYNOLDS NUMBER It can be read as ratio of inertia forces to viscous surface forces

  23. HEAD COEFFICIENT The ratio between the tangential component of the gas velocity at outlet and impeller peripheral speed Euler equation A measure of the impeller capacity to energise the gas

  24. NON DIMENSIONAL PERFORMANCE CURVES

  25. Summary: • Input data: • Suction Pressure • Suction Temperature • Gas Composition • Discharge Pressure Status Equation (BWRS: Benedict Webb Rubin Starling) • Experimental data: • Flow Coefficient • Head Coefficient • Discharge Pressure • Absorbed Power • Efficiency

  26. Main Design Criteria of Compressor • - Efficiency: • 84 - 87 % for compression ratio up to 2 • more than 75 % for compression ratio above 2 • - Operating range: from 70 to 140 % of the design point Design Point

  27. Manufacturing Complete Range of Centrifugal Compressors A comprehensive production for On-Shore and Off-Shore Services since 1960 from the High Volumes - Low Pressure Applications to the Low Volumes - High Pressure Applications • LNG Liquefied Natural Gas • REFINERY • Fluid catalytic cracking • Reforming • Hydrocracking • PETROCHEMICALS • Syngas & Fertilizers: • CO2 compressor for UREA Plants • Ammonia Synthesis • Methanol Synthesis • NATURAL GAS • Oil Production • Gas Production • Gas Lift • Pipeline • Gas Re-injection • Gas Storage Over 3500 Units Sold World Leader in Gas Compression

  28. Low Pressures - High Volumes

  29. Low Pressures - High Volumes MCL - 2MCL - 3MCL - DMCL Compressors • High Volume Flows [up to 200,000 m3/h for MCL - 300,000 m3/h for DMCL] • Low Discharge Pressures [up to 40 bar] • Casings either cast or fabricated • Cast Iron Diaphragms • Radial and Thrust Bearings Tilting Pad type • Shaft End Seals both Oil film type or dry gas seal type

  30. Casings and Diaphragms for High Pressure Compressors

  31. Barrel Casing With Cartridge Concept Internals for Easy Maintenance 3D Impeller Technology Machined by 5-Axis Milling Machines

  32. Gas Pipeline Compressor - PCL Vertically Split Pipeline Compressors • Medium to High Volume Flows [ranging from 80,000 m3/h down to 3000 m3/h] • Low to Medium Discharge Pressures [experienced up to 110 bar] • Low Compressor Ratio [experienced up to 2] • High Polytropic Efficiency [experienced up to 0.86 with vaned Diffusor] • Axial Gas Inlet Arragement or Traditional Side Inlet Flange Configuration • Forged Steel Casings and inner casing • Radial and Thrust Bearings Tilting Pad type (option for magnetic bearings) • Shaft End Seals with Tandem Dry Gas Seals • Standardized casings for one to three impellers and direct coupling to NP Gas Turbines

  33. Compressor Selection • The compressor is normally driven by Gas Turbine or Electric Motor • Compression selection steps: • Estimated absorbed power with dedicated software • Selection of the suitable GT model • Rotating speed becomes an input, related to the selected GT • Final selection of compressor by specific software Compressor Configurators are the E-tools to perform a selection via INTERNET

  34. STAGES STANDARDIZATION • Predesigned and tested stages are used to meet the requested performance and to avoid rotating stall on statoric and rotating components Standardization Ensures Reliability of Predicted Performances

  35. Shaft end sealing TANDEM SEALS EXPERIENCED UP TO 210 BAR STATIC TRIPLE SEALS EXPERIENCED UP TO 290 BAR DYNAMIC AND 310 BAR STATIC

  36. Shaft end sealing • Nuovo Pignone • LARGE EXPERIENCE ON DRY GAS SEALS • Over 200 Compressors with Dry Gas Seals • Sealing pressures at Settling Out conditions up to 4200 PSIA • Dry Gas Seals size up to 250MM Dry Gas Sealing system for 2BCL306C Statoil Veslefrikk Compressor

  37. HONEYCOMB labyrinths • on balancing drums and impellers • to increase rotor system damping capabilities • for High Pressure Applications. Honeycomb for Improved Rotor Stability

  38. Propane Compressor installed at Bintulu Plant

More Related