How to choose materials for power plant flue ducts?
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I would like to ask my friends on Haichuan: Is flue gas from power plants that has not undergone desulfurization considered a highly hazardous substance? For highly hazardous media, Q235B material is often used in the dry flue gas ducts of power plants, which does not comply with the requirements specified in GB/T150.2 (Q235 series materials cannot be used for extremely hazardous media). I would like to ask which standards should be referred to when selecting materials for power plant flue ducts?
I haven’t thought about the standard question; the original poster, please check and reply in this post. When the system is operating normally, the flue gas temperature before the desulfurization tower is usually higher than the dew point corrosion temperature of sulfur dioxide; therefore, in the common boiler exhaust systems, the steel flues located before the desulfurization tower are not typically treated with anti-corrosion measures. Desulfurization towers have been around since the beginning.
The flue gas from coal burning is not highly hazardous; it’s similar to the normal flue gas produced in the chemical industry. What matters are strength and corrosion resistance, and Q235B is more than sufficient for this purpose.
The selection of materials and design for flue ducts are based on the standards set out in DL/T 5121-2000, \"Technical Specifications for the Design of Flue, Air, and Coal Powder Ducts in Thermal Power Plants + Associated Design Calculation Methods\", which provides the formulas for calculating flue ducts.