Condenser Water Quality Monitor

Control Systems

Overview

During operation of a thermal power plant, the condenser can develop a seawater leak.

If corrective action against the seawater leak is delayed, maintenance for the boiler and turbine will become necessary. This may lead to extensive problems and could result in months of plant downtime.

This type of trouble can be prevented by early action to correct the seawater leak.

Considering this fact, Mitsubishi Power developed a condenser water quality monitor to eliminate the uncertainty of measurement and make it easy for operators to identify seawater leaks. You can detect local changes in water quality caused by a seawater leak by using this condenser water quality monitor.

Features

More Precise Measurement is Possible than with Conventional Products

Measurement is also possible during startup and shutdown periods, whereas a conventional acid conductivity meter cannot be used during those periods.
Also, measurement is not affected by the presence of CO2.
Note that the sensitivity drops for about 2 hours during vacuum ramp-up at startup.

Distribution Measurement Effective for Identifying Leak Location

Distributed conductivity measurement is superior to the conventional method which measures conductivity only at sampling points (for example, four points). In addition, the conductivity distribution inside the hot well can be displayed.

Principles of Detection (Conductivity Distribution Meter): Patent Pending

Apply a voltage pulse to a sensor cable and measure the voltage change over time at the input terminal.
The voltage change over time can be converted to the water conductivity change along the sensor cable.

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Measurement Principles for a Conductivity Distribution Meter
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Measurement Principles for a Conductivity Distribution Meter

System Configuration

The electrical characteristic of the sensor cable installed inside the condenser is analyzed. A PC continuously records the data to identify the presence of contaminated water.

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Condenser Water Quality Monitor

Specifications

The specifications of the condenser water quality monitor are given in the table below.

Minimum detection concentration 0.15% (concentration of seawater in condensate)*
Position resolution Maximum of 1m for the sensor cable length
Measurable distance Approximately 100m for the sensor cable length
Measurement cycle Approximately 1 minute
  • Corresponds to 10L/hour seawater leak over one square meter for a condenser with a 225m2 area and 1,570m3/hour flow rate.

Comparison of Water Quality Monitor Sample Measurement and Salinometer

A salinometer cannot measure conductivity from when the unit stops until several hours after the unit restarts.
This water quality monitor can detect leaks correctly except during the vacuum ramp-up period at startup.
Leaks can also be monitored visually through a 2D map display.

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Comparison of Sensor Measurements Taken with Actual Equipment and a Salinometer at Existing Facilities.
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Sample of 2D Map Display