Regarding external heat extraction (fluidization air) --- (lift air)
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Since the main air supply for the catalytic unit was switched to the backup unit, the amount of material processed has decreased. As a result, the heat extraction from outside also isn’t very effective, with fluctuations that affect the steam pressure. When making adjustments, which method should be used to control the fluidizing air and increase its flow? 1. The fluidization air is strong while the lifting air is weak. 2. The fluidization air is weak while the lifting air is strong. Is it better to keep the fluidization air almost unchanged and fine-tune the lifting air, or to keep the lifting air unchanged and fine-tune the fluidization air? I really want to know! What is the logic behind this? Thank you! ! ! !
Once circulation is established, the adjustment should focus on increasing the wind flow; of course, it is necessary to first adjust the fluidization wind and the loosening points properly
Our system basically maintains the flow rate of the fluidizing air constant and adjusts the opening degree of the slide valve to regulate heat extraction; we’re not sure what method you use for heat extraction
In my opinion, the heat extraction effect is poor; the fluidization air and loosening air should be adjusted accordingly!
Your external heat extraction device doesn’t have a slide valve, right? This type of external heat extractor relies on cyclic heat extraction, with the fluidization air at the loosening point being used to regulate the fluidization state. However, when the amount of heat extracted is low, it is not possible to use the lift air (as it cannot be controlled); in such cases, backmixing is used for heat extraction. Once the amount of heat extracted reaches a certain level, cyclic heat extraction is adopted instead. The transition to this mode is somewhat complicated: when less heat needs to be extracted, backmixing is used; as the amount of heat extracted increases, the fluidization air flow rate increases as well. When switching to cyclic heat extraction, it is necessary to adjust the fluidization air, the loosening point settings, and the lift air flow rate, which results in an unstable phase. In your case, it is recommended that you monitor closely the changes in inlet density and outlet temperature. If there is a significant decrease in burning, and the heat input is low as well, then it’s necessary to change the approach if the temperature remains low. A special case will be introduced: in some units, the bed density of the regenerator may experience repeated fluctuations, which can also affect the external heat exchanger
If the fluidization air and the lifting air compete for the same volume of air, I think it might be due to the low pressure of the pressurization air. I suggest reducing the butterfly valves for the primary and secondary air in the auxiliary combustion chamber slightly; by increasing the pressure at the inlet of the pressurizer, the aforementioned problem can be alleviated. It’s worth giving it a try
It’s a typical pneumatically controlled type; I’m not sure if it’s an improved version with a slide valve. If it has a slide valve, it’s easier to adjust; but in the case of the original model, the catalyst circulation rate is lower when less heat needs to be extracted, making it difficult to make adjustments. Generally, the fluidization air is sufficient to ensure normal fluidization for heat removal; the density should be within the normal range, and adjustments are made by increasing the airflow and the opening degree of the slide valve.