In order to ensure the safe and stable operation of the boiler, the iron content in the boiler water must be strictly controlled.China's water and vapour quality standards for thermal power plants specify iron content limits for boiler feedwater, furnace water and steam.For example, for boilers with supercritical parameters, the iron content in the feedwater should not exceed 20 μg/L.This paper will look at why power plant boiler water should be tested for iron content and the relevant testing standards.
1. Scaling and corrosion: Iron ions in the high temperature and high pressure conditions are prone to form oxides or hydroxide precipitates, these precipitates will be attached to the boiler heating surface, the formation of difficult to remove the scale.The presence of scale reduces heat transfer efficiency, increases fuel consumption, and in severe cases may lead to localised overheating of the boiler or even pipe bursting accidents.In addition, iron ions may accelerate the corrosion process of metallic materials, especially when dissolved oxygen is present in the water, triggering severe oxygen corrosion phenomena.
2. Steam quality degradation: High iron content will lead to steam entrainment of impurities, affecting steam quality, which in turn will cause damage to key components such as turbine blades, shortening equipment life and increasing maintenance costs.
3. Reduced efficiency of the thermal system: With the accumulation of iron deposits, the pipeline circulation area decreases and the resistance increases, leading to a rise in pumping energy consumption and a reduction in the overall thermal system efficiency.
For the detection of iron content in boiler water of power plants, there are corresponding standards stipulated in China and internationally.The following are some of the main standards:
- GB/T 12145-2016 Water Vapour Quality of Thermal Generating Units and Steam Power Equipment:The standard is a Chinese water and vapour quality standard for thermal power plants, which specifies iron content limits for boiler feedwater, furnace water and steam.For example, for boilers with supercritical parameters, the iron content in the feedwater should not exceed 20 μg/L.
- ASTM D1193-18《Standard Specification for Reagent Water》：The American Society for Testing and Materials (ASTM) issued reagent water standards, although mainly used in the laboratory, but its provisions of pure water indicators can also be used as a reference, especially some of the high purity requirements of the occasion.
- ISO 5667-3:2017《Water quality - Sampling - Part 3: Guidance on the preservation and handling of samples》：International Organisation for Standardisation (ISO) guidelines on water quality sampling, preservation and handling provide guidance on the correct acquisition of representative samples to ensure the accuracy of test results.
- Other industry standards: In addition to the national and international standards mentioned above, there are many industry-specific standards, such as nuclear power plants and chemical companies, which have developed more stringent iron content control requirements based on their respective characteristics.
Above is the whole content of why power plant boiler water should be analysed for iron content and testing standards.By following the relevant standards and implementing effective water quality management and monitoring, various problems caused by excessive iron content can be effectively avoided, providing a solid guarantee for power production.Erun environmental protection thermalpower plant boiler water trace iron content analyser, according to DL/T 502.25-2019 "thermal power plant water vapour analysis method" developed.It is used in thermal power, chemical fertiliser, metallurgy, environmental protection, pharmaceutical, biochemical, food and water industries.It is suitable for the analysis and determination of iron content in boiler feed water, condensate, steam water, cooling water of internal cooling generator, furnace water and natural water.If you need detailed information, please consult customer service.
