Download - Centrifugal Compressor

ContentsPurposeOverview

CompressorComponentsAuxiliaries

Job RequirementsKey Points API 617 Essentials

PurposeTo compress gas from a lower pressure to a

higher pressureUsed in many applications:

Fertilizers – Ammonia Syn Gas, Urea SynthesisEthylene – Charge Gas, Refrigeration GasRefineries – Recycle, Cracked GasNatural Gas – LNG (propane, refrigerant), Gas

Lift, Gas Reinjection

Overview - CompressorDynamic compressorBasic principles

Centrifugal action

P4,V4,T4

P2,V4,T2

P3,V1,T3

P3,V1,T3

P5,V1,T5

P1,V1,T1

P5,V1,T5

Overview – CompressorEnergy Conversion

Overview – CompressorApplication Parameters

Gases - All Types of Gases Speed - 3,500 to 26,500 RPMPressure – Up to 1,000 bar Flow Range – 1,000 to 300,000 m3/hrNumber of Stages - 1 to 10 ImpellersNatural gas – pressure ratio up to 2 per stage

Overview – CompressorType of compressor

Single stage Booster application

Overview – CompressorMultistage

Axially (Horizontally) split Radially (Vertically) split

Axially Split

Radially Split

Overview - CompressorHorizontal split or vertically split

Horizontal < 60 bargPer API 617, radially split if partial pressure of

Hydrogen at MAWP >1380 kpag or 200 psig.

Overview - CompressorMultistage types:

In-lineBack-to-back

Overview - CompressorMultistage types (continued):

Compound / Side-streamDouble flow

Overview - Components

Overview – Inlet Volute

Overview - Impeller

Overview - Diaphragm

Overview – Stage and Diffuser

Overview – Discharge Volute

Overview – Rotor

Overview – Stator

Overview – Assembly

Job requirementProcess data

Inlet pressure, temperatureGas compositions (each stage)Discharge pressureFlow (mass or volume)

Driver compatibilityVariable speed (GT, ST, VFD)Fixed Speed (EM)

Job requirementScope of supply – incl. equipment & test

reqmtMajor equipmentAuxiliariesSparesTestsInstallation & Commissioning

Layout, footprint and weightMaterials

Job requirementCompressor selection / flexibility

Operating rangeSparing/operation philosophyRe-bundling option

RotordynamicsAvoid unwanted incidence – high vibration,

short lifecycleVendor’s standard

Job requirementCompliance to specs & int’l standards

Project specAPI 617, 614, 616, 612, 670, 613

CostBase priceOptional

Key points to considerMultiple process conditionsPower / EfficiencyStagesTurndown capabilitiesUtility consumption (dry gas seal, lube oil,

utility)Scope of supply

AuxiliariesTest requirement

Specifications & Standards

Key points to considerTests

Performed tests at plant Hydrostatic test on casing Impeller overspeed test Mechanical run test – continuous running

Optional Helium leak test Performance test – meet contract requirement (PTC

10) String test

API 617 EssentialsAPI-617 7TH.pdfPerformance map (pg 92)Rated point – operating condition @ 100% speed,

highest capacityNormal point – optimum efficiency expected,

certified pointMAWP – RV setting or 1.25 x max discharge

pressureStd vs Normal volume – 15°C@atm vs 0°C@atmMCOS – 105% for variable speed or 100% for

motor