Introduction: Why is Water Quality the "Lifeline" of a Thermal Power Plant?
In simple terms, the key parameters for water quality testing in thermal power plants include pH, conductivity, dissolved oxygen, silica, sodium ions, phosphate, and more. These are primarily monitored in real-time, continuously, using online chemical analyzers.
This is no overreaction. Imagine the plant boiler as a giant "pressure cooker." Poor water quality instantly triggers three major crises: scaling, corrosion, and carryover. Just a 1mm layer of scale can increase fuel consumption by 2% to 5%. More alarmingly, corrosion can lead to tube bursts and forced outages, with unplanned shutdowns often causing millions in economic losses. Therefore, real-time online water quality monitoring is no longer an "auxiliary" task but the "nerve center" ensuring safe, economical, and environmentally compliant plant operation.
Module 1: Feedwater System Monitoring – Guarding the "First Line of Defense"
Feedwater, the treated water supplied to the boiler, must be of high purity as it directly determines the internal environment of the boiler. The national standard GB/T 12145-2022 "Water and Steam Quality for Thermal Power Generation Units and Steam Power Equipment" specifies clear requirements.
Application Scenario: At a 600 MW subcritical unit, operators noticed a slow rise in dissolved oxygen from 3 μg/L to 8 μg/L via the online dissolved oxygen analyzer. This prompted an inspection that found loose internal parts in the deaerator, averting a system-wide oxygen corrosion risk.
Module 2: Boiler Water & Steam System – The "Quality Gatekeepers" for High-Purity Steam
The water inside the boiler drum and the generated steam operate under high temperature and pressure, demanding even stricter quality control.
Instrument Reference: In recent tender documents for power plant chemical analyzers, integrated solutions like the ERUN-SZ Series Power Plant Online Boiler Water Analyzer frequently appear. It integrates measurement modules for various parameters (e.g., silica, phosphate, hydrazine) into a single unit, reducing sample tubing, improving data centralization, and enhancing maintenance efficiency, making it particularly suitable for deployment in space-limited areas.
Module 3: Condensate System – The "Quality Control Center" for Reuse
The steam that condenses after performing work in the turbine is the plant's primary water recycle. However, this condensate is highly susceptible to contamination from cooling system leaks.
Case Study: A coastal 1000 MW unit experienced a sudden deterioration in condensate quality, which was difficult to locate through routine inspection. It was the real-time data trends from the online conductivity and sodium analyzers installed at the condensate polisher outlet that pinpointed the leak to a specific location in the B-side condenser, enabling rapid isolation and repair.
Conclusion: The Value of Building an Intelligent Water-Steam Monitoring System
In summary, modern water quality management in thermal power plants has evolved beyond manual sampling towards automation and intelligence centered on online chemical analyzers. This system is not just about compliance with national standards; it is a crucial strategy for power plants to achieve:
Safe Operation: Early warning of corrosion and scaling risks, preventing major failures.
Economic Benefits: Improved heat rate, extended equipment life, and reduced outage losses.
Environmental Compliance: Optimized blowdown and chemical dosing, reducing chemical consumption and environmental impact.
Investing in a reliable and accurate online water analysis system is like employing a tireless "chemical doctor" for the power plant, whose long-term return far outweighs the initial investment. When selecting equipment, focus on measurement accuracy, long-term stability, anti-interference capability, and ease of integration with the plant's DCS/SIS systems.
