Heating operation systems are inseparable from water, and the quality of water directly affects the operation efficiency and safety of the system. The thermal oil heater in the heat center is closely related to water quality, so whether the water quality is qualified is an important part of the operation management of the heating system. The following are some precautions in the use of thermal oil heaters.
The feed water at the initial stage of boiler operation and the make-up water during normal operation come from raw water. Raw water contains various impurities. If it enters the system without treatment, it will cause scaling and corrosion on the heating surface of the boiler, seriously affecting the safe and economic operation of the boiler.
The following are the matters of heating surface scaling and electrochemical corrosion that have a greater impact during boiler operation:
I. Formation of Scale on Heating Surface
The thermal conductivity of scale is dozens of times worse than that of metal. When scale forms in the heating tubes with high heat load, the temperature of the metal tube wall will rise sharply, causing bulging or even tube bursting. Scaling not only endangers boiler safety but also reduces economy. When a 1mm thick scale is formed, fuel consumption will increase by 1.5-2.0%.
II. Internal Corrosion
Corrosion can be divided into three types: metal corrosion (uniform corrosion and local corrosion), chemical corrosion, and electrochemical corrosion (accompanied by current generation during the corrosion process). Generally, internal corrosion includes steam-water corrosion, internal electrochemical corrosion, and caustic embrittlement.
Caustic embrittlement is intergranular corrosion, which occurs along the grain boundaries of the metal, forming extremely fine zigzag cracks. Once caustic embrittlement occurs, the damage to the metal accelerates. When cracks are detected, the metal damage has already reached a serious level. The harm of caustic embrittlement is significant. As a result of caustic embrittlement, in mild cases, the boiler must be shut down; in severe cases, an explosion may occur.
In summary: Water treatment is relatively strict in terms of management and technical requirements, and sufficient attention should be paid to it. The problems of heating surface tube bursting and scaling causing reduced thermal efficiency during operation should be resolved. It is hoped that management, technical, and operational personnel at all levels rely on science and technology, strengthen management, and promote the healthy development of the heating industry.
