Turbine Speed Reducer Load Control via Working Fluid Bypass

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

In closed cycle gas turbines using atomic reactors as heat sources, the existing methods for accelerating turbine speed are inefficient, leading to prolonged startup times and increased plant costs due to the limitations on temperature elevation rates and the need for large starting apparatus capacities.

Innovation Solution

A method of controlling the load applied to the speed reducing portion by adjusting the flow rate of the working fluid bypassed from the delivery side to the suction side of the compressor, based on the elapsed time and pressure ratios, to maintain a predetermined torque and prevent surging, thereby optimizing the torque applied to the speed reduction gear.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the temperature elevation rate is restricted by reactor restrictions (e.g., 100°C/h), then the reactor safety is improved, but the startup time of the turbine is prolonged

Engineering Contradiction:
Improvereactor safetyVSAvoidturbine startup time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The invention changes the parameter of working fluid amount in the closed cycle system. By reducing the working fluid amount during startup, the turbine can accelerate faster without exceeding reactor temperature restrictions, and by restoring the full working fluid amount after startup, the system returns to normal operation. This temporary parameter change resolves the contradiction between reactor safety and startup time.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the working fluid amount is reduced to reduce drive torque and starting apparatus capacity, then the plant cost is reduced, but the startup time is prolonged

Engineering Contradiction:
Improvestarting apparatus capacityVSAvoidspeed elevation time
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The invention applies dynamic control to the working fluid amount rather than a static reduction. The working fluid amount is temporarily reduced only during the startup phase when torque reduction is needed, and then restored to full amount after startup. This dynamic adjustment allows the system to benefit from reduced starting apparatus capacity while minimizing the impact on startup time.

Inventive Principle:
Principle #15Dynamics

3Reliability

If the drive torque is reduced to prevent fretting in the speed reduction gear, then the gear reliability is improved, but the torque loaded to the gear is insufficient causing fretting due to self weight

Engineering Contradiction:
Improvegear reliabilityVSAvoidtorque loaded to gear
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The invention applies periodic action by controlling the working fluid amount in phases: reducing it during startup to provide minimum necessary torque that prevents fretting, and then restoring it to full amount during normal operation to ensure adequate torque loading. This periodic adjustment of working fluid amount resolves the contradiction between preventing fretting during startup and maintaining adequate torque during operation.

Inventive Principle:
Principle #19Periodic action

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 approach allows for efficient startup operations by accurately controlling the load on the speed reducing portion, reducing the risk of fretting and maintaining optimal torque levels, even under temperature restrictions, thus enhancing the efficiency and cost-effectiveness of the turbine acceleration process.

Implementation Method 1

circulating a working fluid in a closed system by using an atomic reactor or the like for a heat source

Methodology Applied
Scientific EffectHeat absorption: Absorption (physical)

Implementation Method 2

the revolution number is increased by an acceleration torque of the turbine per se

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP2334911B1Method of controlling turbine equipment and turbine equipment
Publication Date: 2016.08.10 MITSUBISHI HEAVY IND LTD
  • EP2334911B1 patent drawingFigure 1
  • EP2334911B1 patent drawingFigure 2~3
  • EP2334911B1 patent drawingFigure 4~5

AI summary

To provide a method of controlling a turbine equipment and a turbine equipment capable of carrying out a starting operation of controlling a load applied to a speed reducing portion while complying with a restriction imposed on an apparatus provided at a turbine equipment. The invention is characterized in including a speed accelerating step (S1) of increasing a revolution number by driving to rotate a compressing portion and a turbine portion by a motor by way of a speed reducing portion, a load detecting step (S2) of detecting a load applied to the speed reducing portion by a load detecting portion, and a bypass flow rate controlling step (S3) of increasing a flow rate of a working fluid bypassed from a delivery side to a suction side of the compressing portion when an absolute value of the detected load is equal to or smaller than an absolute value of a predetermined value and reducing the flow rate of the bypassed working fluid when equal to or larger than the absolute value of the predetermined value.