Condenser Vacuum Stabilization via Cooling Water Flow Control

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Solution Overview

Problem

The condenser vacuum in power plants fluctuates with seasonal changes in cooling-water temperature, limiting the ability to maintain maximum output due to constraints on cooling-water quantity and flow velocity, which affects steam turbine efficiency.

Innovation Solution

A condenser design incorporating a circulating path, bypass tube, control valve, and booster pump to control cooling-water flow rate and temperature, maintaining constant water intake and discharge temperature while adjusting cooling-water distribution to stabilize condenser vacuum.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the quantity of cooling water supplied to the condenser is increased to maintain condenser vacuum, then the condenser vacuum is improved, but the discharge water temperature increases and environmental constraints are violated

Engineering Contradiction:
Improvecondenser vacuumVSAvoiddischarge water temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The cooling water circulation system is divided into multiple independent circulation paths (first circulation path with first cooling water, second circulation path with second cooling water). This segmentation allows different portions of cooling water to be controlled independently, enabling the system to maintain condenser vacuum while controlling the temperature of discharged water by selectively managing which circulation paths are active and their respective flow rates.

Inventive Principle:
Principle #1Segmentation

2Temperature

If the quantity of cooling water is reduced to maintain discharge water temperature, then environmental constraints are satisfied, but the condenser vacuum deteriorates

Engineering Contradiction:
Improvedischarge water temperatureVSAvoidcondenser vacuum
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The system dynamically adjusts the flow rates of cooling water in different circulation paths using flow rate control means. By dynamically balancing the quantity of cooling water between the first and second circulation paths, the system can maintain optimal condenser vacuum while ensuring discharge water temperature remains within environmental constraints, adapting to varying thermal loads and ambient conditions.

Inventive Principle:
Principle #15Dynamics

3Productivity

If the flow velocity of cooling water is increased to maintain cleanliness of heat transfer surface, then the heat transfer efficiency is improved, but the energy consumption increases

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidenergy consumption
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

Different circulation paths are assigned different flow velocities based on their specific functions and requirements. The first cooling water circulation path can operate at a higher flow velocity to maintain cleanliness of the heat transfer surface in the tube nest, while the second circulation path can operate at a lower flow velocity where high velocity is not critical. This local differentiation of flow quality optimizes heat transfer efficiency while minimizing overall energy consumption.

Inventive Principle:
Principle #3Local quality

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 configuration stabilizes condenser vacuum and reduces output fluctuations, ensuring maximum power plant efficiency by maintaining optimal steam temperature and heat transfer efficiency despite varying cooling-water conditions.

Implementation Method 1

control valve (3)... to control the flow rate of the cooling water

Methodology Applied
Scientific EffectPressure drop: Pressure Drop

Implementation Method 2

booster pump (4)... to boost the flow rate of the cooling water

Methodology Applied
Scientific EffectPumping: Pump

Implementation Method 3

tube nest (10)... cooling water flows... steam is condensed on the outside surface of the cooling tubes

Methodology Applied
Scientific EffectHeat transfer: Conduction (thermal)

Implementation Method 4

Steam led to the condenser is condensed on the outside surface of the cooling tubes

Methodology Applied
Scientific EffectCondensation: Condensation

Implementation Method 5

Cooling water introduced into the cooling tubes... draws condensation latent heat from the steam

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP2428654B1Condenser and steam turbine power plant
Publication Date: 2013.10.23 HITACHI LTD
  • EP2428654B1 patent drawingFigure 1
  • EP2428654B1 patent drawingFigure 2
  • EP2428654B1 patent drawingFigure 3

AI summary

Disclosed herein is a condenser that can restrain fluctuations in the condenser vacuum while satisfying cooling water conditions, and a power generating installation using the condenser. The condenser comprises: a circulating path 110 through which cooling water taken from a water source flows; a tube nest 10 for condensing steam from a steam turbine with the cooling water in a plurality of cooling tubes; a discharge path 120 through which the cooling water discharged from the tube nest flows; a bypass tube 50 through which the cooling water flows from the circulating path 110 toward the discharge path 120; a control valve 5 for controlling the flow rate of the cooling water supplied from the circulating path 110 to the discharge path 120; a recirculating path 40 through which the cooling water flows from the discharge path toward the circulating path 110; and a booster pump 4 for controlling the flow rate of the cooling water supplied from the discharge path 120 to the circulating path 110; wherein any one of the temperature, the flow rate and both the temperature and the flow rate of the cooling water to flow through the two tube nests is deviated from the temperature and the flow rate of the cooling water on the upstream side of the circulating path 110 by the control valve 5 and the booster pump 4.