Unable to find the cause of problems with the top circulation in delayed coking
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I have a delayed coking unit, and recently I’ve been experiencing problems with maintaining the liquid level in the top circulation oil tank. This issue becomes more severe when the temperature in the top circulation reflux tower is above 110°C, or when there is an increase in gas flow – for example, when the amount of oil processed increases or during minor gas injection operations. In such cases, the liquid level in the top circulation tank drops rapidly, while the liquid level in the gasoline tank rises sharply. What do you all think might be the cause of this problem? What is the best way to address it? The temperature of the top circulation liquid during the previous period was between 140–150°C, while it has been around 135°C in the past couple of days. Due to the inability to maintain an appropriate level of liquid in the top circulation system, bottom reflux was hardly used; the flow rate of liquid returning to the tower is around 235 tons
When the cooling capacity of the top circulation system is sufficient, increasing the extraction temperature can slightly reduce the volume of fluid in the top circulation cycle; it is important to ensure that the top temperature and the quality of the gasoline remain satisfactory.