Power Plant Control for Rapid Load Increase Without Storage Tank

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Solution Overview

Problem

The existing condensate throttling operation control methods in power plants require costly equipment upgrades, including a deaerator with sufficient capacity and a condensate storage tank, to manage rapid load increases, leading to increased equipment costs and dependency on deaerator capacity.

Innovation Solution

A power plant configuration that includes a steam generation device, turbine, condenser, deaerator, feed water heater, deaerator water level control valve, extraction system with an extraction valve, and an auxiliary steam introduction system with an auxiliary steam control valve, which allows the extraction valve to close and the auxiliary steam valve to open during rapid load increases, maintaining deaerator water level control valve openness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the deaerator water level control valve is closed to temporarily increase power generation output, then the power generation output is increased, but the deaerator water level is lowered and a deaerator with sufficient capacity is required, increasing equipment cost

Engineering Contradiction:
Improvepower generation outputVSAvoiddeaerator capacity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention introduces a condensate recirculation system as an intermediary mechanism. The recirculation pump and control valve create a feedback loop that returns condensate from the deaerator outlet back to the deaerator inlet, acting as a mediator to maintain water level without requiring increased deaerator capacity

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention implements a feedback control system where the opening degree of the recirculation control valve is adjusted based on the deaerator water level. The control unit continuously monitors water level and dynamically adjusts the recirculation flow to maintain stable water level during rapid load changes

Inventive Principle:
Principle #23Feedback

2Productivity

If the deaerator water level control valve is closed to increase power generation output, then the power generation output is increased, but a condensate storage tank is required to avoid water level raising in condenser, increasing equipment cost

Engineering Contradiction:
Improvepower generation outputVSAvoidcondensate storage tank
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The invention extracts the water level control function from the deaerator water level control valve and implements it through the recirculation system. By taking out the control function from the main condensate flow path and placing it in the recirculation loop, the system can manage water level without requiring a separate condensate storage tank

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The recirculation pump and control valve serve multiple functions: they maintain deaerator water level, manage condensate flow during load changes, and prevent water level raising in the condenser. This multi-functionality eliminates the need for dedicated condensate storage tanks

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 eliminates the need for a condensate storage tank or reduces its capacity, allowing power generation output increases independent of deaerator capacity, thereby suppressing equipment costs.

Implementation Method 1

a steam generation device (1)

Methodology Applied
Scientific EffectPhase change: Phase Change

Implementation Method 2

a turbine (2-4) which is driven with stream generated by the steam generation device (1)

Methodology Applied
Scientific EffectThermal energy conversion:

Implementation Method 3

a condenser (6) which condenses the steam exhausted from the turbine (2-4)

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 4

a feed water heater (9, 12) which heats condensate whose pressure is risen by a condensate pump (8)

Methodology Applied
Scientific EffectHeat transfer: Heat Exchanger

Implementation Method 5

a deaerator (10) which heats and de-aerates the condensate heated by the feed water heater (9, 12)

Methodology Applied
Scientific EffectHeating: Heating

Data Source

PatentEP3715593B1Power plant and power output increase controlling method for power plant
Publication Date: 2023.04.26 MITSUBISHI HEAVY IND LTD
  • EP3715593B1 patent drawingFigure 1

AI summary

A power plant comprises a boiler (1), a turbine (2, 3, 4), a condenser (6), a feed water heater (9), a deaerator (10), a deaerator water level control valve (30), an extraction system (22) which introduces the steam extracted from the turbine (4) into the feed water heater (9), an extraction valve (31), an auxiliary steam introduction system (50, 23) which introduces auxiliary steam into the feed water heater (9), an auxiliary steam control valve (32) and a control device (100). When a rapid load increase request is made, the control device (100) controls, to orient the extraction valve (31) in a closing direction, to maintain an opening of the deaerator water level control valve (30), and to orient the auxiliary steam control valve (32) in an opening direction.