Discussion on oxygen corrosion issues
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“Oxygen has a strong corrosive effect on alloy steel; all water added to the vaporization system must undergo thorough deoxidation treatment. ”I would like to ask everyone how you handle the quality of water used for make-up water in coal-water slurry gasification?
Therefore, the deoxygenation tank in the water flow system serves this purpose: after various types of make-up water that have been vaporized enter the system, they must pass through the deoxygenation tank to undergo low-temperature deoxygenation before being pressurized and sent to the vaporization system for use. Many people think that a deoxygenation tank is an optional device, but in terms of long-term operation, it is definitely an essential piece of equipment.
The deaerated water tanks in our plant are no longer fed with steam; they are used purely as buffer tanks
All system water is sent to the deaerator; after deoxygenation, it is pumped into the system via a deaerator pump. The deaerator is supplied with low-pressure steam, which is used to heat the water in the deaerator, but it has never been used because the water temperature is already sufficient.
The function of a deaerator is to remove oxygen at low temperatures, and its principle is based on Dalton’s law of partial pressures. Not heating the deaerator has no effect in the short term, but it is not feasible in the long run, as oxygen corrosion will occur in the system’s pipes and equipment
Waste boilers experience leaks due to incomplete deoxygenation of the water; therefore, a deaerator is an essential device. As for the mention of different low-pressure steams earlier, the deaerator functions as a buffer tank – it’s not meant to refer to that. The deaerator accepts steam with a low flash point, and it also applies the principle of partial pressure; both functions exist simultaneously.