Compressor Re-Rates

Designed for Many Years of Reliable Operation

GE has accumulated extensive experience in centrifugal compressor re-rating. You benefit from implementing the latest design techniques and leveraging our experience in new machines and prior retrofit installations. All machines can meet a new specification for any plant application.

Features & Benefits

Re-rating provides substantial benefits, including:

  • Uprating without a major impact on the plant layout
  • Lower operating costs due to increased plant efficiency
  • Increased plant capacity
  • Re-use of existing capital equipment

Internals Selection

We select the compressor internals based on our broad experience, and select impellers and stator components from standardized families we developed. All components are designed in compliance with API standards codes and our internal standards.

Design Standards

Components that are not regulated by codes are designed to the highest engineering standards. Component designs are verified by application of finite element analysis, computational fluid dynamics and model testing where necessary.

The following list shows the standard activities included in a revamping study:

Bundle Selection

  • Axial and radial spacing is available inside casing
  • Impellers and stator parts are selected to optimize performance
  • The mechanical layout is checked

Gas Velocity Check

  • Inlet nozzle
  • Discharge nozzle
  • Inlet plenum gas velocity
  • Discharge volute

Auxiliaries Check

  • Lubricating oil system
  • Seal gas system
  • Anti-surge system

Aerodynamic Check

Rotor-Dynamic and Speed Range

Material Selection

Re-bundling

Re-bundling a centrifugal compressor with new internals increases its performance, which typically increases efficiency, flow rate and/or the polytropic head. The efficiency can usually be increased by 76 to 85 percent, reducing the power required by the compressor and thereby saving fuel. The additional power can be used to increase the head and flow rate. The new internals can be designed to increase the flow rate up to 30 percent of the nominal point, depending on the compressor size.

We generally supply the following new internal components for each centrifugal compressor:

  • Inlet volute
  • Counter casing
  • Discharge diaphragm
  • Intermediate diaphragms
  • Labyrinths
  • Rotor assembly including six impellers, balance piston and dry gas seals
  • Tilting pad type journal bearings
  • Dry gas seals

We simulate the operating characteristics of the proposed centrifugal compressor and present the results of the verification.

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