Retrofitting Double Flow Steam Turbine to Single Flow

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Solution Overview

Problem

Double flow steam turbines often operate with mismatched exhaust areas and condenser conditions, leading to inefficiencies and performance issues due to lower mass flow or higher backpressure than designed for.

Innovation Solution

Retrofitting a double flow steam turbine by converting it into a single flow steam turbine, where only the inner module is replaced, and the outer casing and connections remain unchanged, with new rotor and stator blades, balancers, and extraction chambers to optimize steam flow and axial thrust balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the exhaust areas are reduced to match actual condenser conditions, then efficiency and performance are improved, but the turbine structure requires complex modification

Engineering Contradiction:

ImproveefficiencyVSAvoidturbine structure modification

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The turbine is divided into modular components (rotor, stator blades, casing) that can be independently replaced. The invention segments the modification task into replacing only the necessary internal components rather than the entire turbine structure, thus improving efficiency while controlling complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The outer casing is retained and reused for the modified single-flow configuration, demonstrating multi-functionality. The same casing structure serves both the original double-flow configuration and the modified single-flow configuration, reducing modification complexity while achieving efficiency improvements.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Productivity

If the entire turbine structure is replaced to optimize steam flow, then performance is improved, but cost and time increase significantly

Engineering Contradiction:

ImproveperformanceVSAvoidretrofitting time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The invention extracts and replaces only the specific components that need modification (rotor, stator blades, inlet belt) while leaving the functional outer casing in place. This selective extraction approach improves performance by optimizing steam flow paths while significantly reducing retrofitting time compared to complete replacement.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The method involves preliminary planning to identify exactly which components need replacement versus which can be retained. By pre-determining the scope of modification (only internal components, not the entire structure), the retrofitting process is streamlined, reducing both time and cost while achieving performance goals.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the turbine is converted from double flow to single flow configuration, then exhaust area matching with condenser is improved, but the turbine requires significant structural modification

Engineering Contradiction:

Improveexhaust area matchingVSAvoidconfiguration change

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention transitions from a symmetric double-flow configuration to an asymmetric single-flow configuration. By replacing the rotor and stator blades with designs optimized for single-flow operation, the turbine achieves better adaptability to condenser conditions while the modification is managed through component replacement rather than complete redesign.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The invention changes key operational parameters (steam flow path, exhaust area characteristics) by replacing specific components. The rotor and stator blades are redesigned with different geometric parameters optimized for single-flow operation, enabling better exhaust area matching with the condenser while managing complexity through targeted parameter changes rather than complete structural overhaul.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method improves efficiency and performance while being cost-effective and time-efficient by matching exhaust areas with condenser conditions without replacing the entire turbine structure.

Implementation Method 1

Steam is supplied via an inner casing with an inlet belt and passes through the steam paths to be then discharged through exhaust areas

Methodology Applied

Scientific EffectSteam expansion: Heat Engine

Data Source

PatentUS9242316B2Method for retrofitting a double flow steam turbine

Publication Date: 2016.01.26 GE VERNOVA INFRASTRUCTURE TECHNOLOGY LLC

AI summary

The method for retrofitting a double flow steam turbine includes opening an outer casing of the steam turbine, removing the blade carriers and the stator blades, removing the inner casing with inlet belt, removing the double flow rotor and the rotor blades. Thus, the method includes the further steps of providing a new single flow rotor and new rotor blades different from the rotor blades connected to the double flow rotor, providing balancers connected to the single flow rotor, to balance the axial thrust, providing new stator blade carriers and new stator blades different from the stator blades associated to the double flow rotor, providing a new inner casing with inlet belt, providing a passage between the inner casing and the outer casing, closing the outer casing.