Phosphate (PO4^3-) content is an important indicator of boiler water quality.The testing standard of boiler water phosphate is mainly based on "GB/T 6913-2023 Analytical Methods for Boiler Water and Cooling Water Determination of Phosphate".According to the standard, the determination of phosphate is applicable to the measurement of orthophosphate, total inorganic phosphate, and total phosphate in boiler water and cooling water within the range of 0.05mg/L~50mg/L.This paper will briefly describe the testing standards, limit requirements and analysers used to test boiler water quality for phosphate in boiler water in thermal power plants.
According to the standard DL/T 805.2-2004 "Guidelines for Steam Water Chemistry in Thermal Power Plants Part 2: Phosphate Treatment of Boiler Furnace Water", the monitoring of phosphoric acid (PO4^3-) is an important means of evaluating the effectiveness of boiler water treatment.The standard details specific criteria for the quality of furnace water during phosphate treatment, emphasising the control range of phosphate content to balance the need for corrosion and scaling prevention.Specifically, the concentration of phosphate recommended by the standard should be determined based on a combination of factors such as the operating pressure of the boiler, the intensity of evaporation and the quality of the feed water.In general, for high pressure and higher rated boilers, phosphate concentrations should be maintained within a specific low level range to avoid localised concentrated corrosion problems caused by phosphate hiding phenomena.
According to the Chinese national standard GB/T 6913-2023 Analytical Methods for Boiler Water and Cooling Water Determination of Phosphate, the determination of phosphate is applicable to the measurement of orthophosphate, total inorganic phosphate, and total phosphate in boiler water and cooling water in the range of 0.05mg/L~50mg/L.The standard specifies a variety of determination methods, such as titration and ultraviolet spectrophotometry, and provides a detailed description of the treatment of water samples, the selection of reagents, and experimental conditions.
For phosphate content in boiler water in thermal power plants, the following limits should be strictly adhered to:
Boilers with rated power less than 4.2 MW: Phosphate in pot water should be between 10-50 mg/L;
Boilers with rated power greater than or equal to 4.2 MW: The phosphate content of the pot water should be between 5 and 50 mg/L.
These limits are designed to ensure that the phosphate does what it is supposed to do, but does not become too concentrated and cause other problems, such as excessive deposits affecting heat transfer efficiency or increased maintenance costs.
Phosphate analyser, developed according to DL/T502.13-2006 "Thermal power plant water vapour analysis methods - determination of phosphate" and GB/T6913-93 "boiler water and cooling water analysis methods".Apply to power plants, chemical fertiliser, metallurgy, environmental protection, pharmaceutical and other industries applicable to demineralised water, steam condensate, furnace water and other water phosphate content analysis, detection.The instrument light source adopts imported monochrome cold light source, excellent performance, stable signal, low power consumption, long life; automatic timing reminder function, convenient for the operator to use, improve work efficiency; data cycle storage, automatically clear the overflow, simple operation, easy to query, power-off data storage time of more than 10 years.
The above is the thermal power plant boiler water phosphate testing standards, limit requirements and testing boiler water quality analyser details.The testing standards and limit values of phosphate in boiler water of thermal power plants are of great significance to ensure the safe and efficient operation of boilers, and the concentration of phosphate in boiler water is strictly controlled by following the relevant national standards and adopting advanced testing techniques and instruments.For more product information about the Phosphate Water Analyser for Thermal Power Plants, please contact customer service.
