Level of the catalyzed re-refining tank
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During operation, when the liquid level in the re-refining tank is low, should the re-refining flow back to the tower be increased or decreased?
The level in the re-refining tank is primarily influenced by changes in the degree of reaction and the amount of re-refined oil fed back. The reaction depth is large, resulting in a drop in the liquid level ； As the amount of oil reprocessed increases, the liquid level drops. In addition, changes in the tray temperature of the reprocessed oil distillate layer and the tray temperature of the diesel distillate layer also affect the liquid level in the reprocessed oil tank. The liquid level in the re-refining tank is dropping; a short-term adjustment should involve reducing the amount of material returned to the tower. Appropriate adjustments should be made according to the specific circumstances.
Of course, the reflux to the reprocessing tower should be reduced, and at the same time, the reprocessing of the reprocessed oil should be decreased while appropriately increasing the reflux to the second intermediate tower.
Increase the flow back to the tower, raise the liquid level in the fractionation tower, reduce the pressure of the heavier components, and also increase the amount of oil being reprocessed, which helps to raise the liquid level in the reprocessing tank.
The reaction depth should be regulated by the reaction itself; the fractionation control should be turned down. Last edited by chengkang on 2009-3-29 19:04.]
If the decrease in the level of the reprocessing tank is caused by changes in the reaction depth, the reaction depth can be appropriately reduced to prevent both the level of the reprocessing tank and that of the distillation tower from dropping or even reaching zero. Refining tanks or fractionation towers can be used to replenish crude oil when necessary. If the decrease in the level of the reprocessing tank is caused by a change in the reprocessing volume, it is sufficient to adjust the reprocessing volume. If there are changes in the properties of the raw materials or the processing volume, the operations can be adjusted accordingly. I think, as long as the liquid level in the distillation tower is stable, why adjust the flow rate of the reprocessed oil entering the distillation tower?
Thank you all for your answers. The level of the reprocessed oil is part of the assessment for the team; there are also specified limits on the amount of reprocessed oil that goes into the reactor, and this amount must remain constant. Moreover, it’s not easy to adjust the degree of reaction, so we can only control the level of the reprocessed oil by adjusting the settings at the distillation unit! !
The amount of reprocessed oil sent back to the tower should be reduced, in order to decrease the volume of oil that goes into the slurry system. This post was last edited by lili95828 on 2009-2-9 at 17:55
If it is determined to be a change in reaction depth, adjusting the reaction temperature is quite effective. If the adjustments available at the fractionation unit are limited, it is possible to reduce the amount of reprocessed oil sent back to the tower, as well as the heat taken from the second stage.
Reduce the reversion tower setting to lower the reaction depth
Our re-refined oil is processed using a full extraction method. As the original poster mentioned, as long as the pump does not get emptied, it is necessary to increase the amount of fluid returned to the tower, thereby increasing the amount of heavy components that condense. This raises the liquid level in the distillation tower, which in turn increases the extraction volume, creating a positive cycle that allows the liquid level in the re-refined oil tank to gradually rise to normal levels.
The level of the reprocessed oil is part of the team’s performance evaluation; this shows that the management wants to have control over the degree of reaction. Although adjusting the amount of reprocessed oil fed back into the tower can temporarily change the level in that tank, it is still necessary to focus on controlling factors such as the degree of reaction, reaction temperature, slag-to-oil ratio, and catalyst-to-oil ratio. You said that the degree of reaction isn’t easy to control – could it be that the production capacity has reached a certain limit? If it really is difficult to control, it would be advisable to discuss this with the management.
Reduce the return tower operation to prevent the reprocessing oil pump from running dry, lower the degree of reaction, and adjust the liquid level in the reprocessing oil tank； Of course, there are also cases where the liquid level in the re-refining tank is not required to be used as a control parameter. This post was last edited by chengkang on 2009-3-29 19:10]
We also do not use the level in the re-refining tank as a control parameter for evaluation. The level of the re-refined oil is generally not adjusted; a level between 20-80% is sufficient. A low level of the reprocessed oil liquid serves only as a reference parameter for the degree of reaction. Also, we don’t carry out separate fractional distillation; the requirements for all positions involve catalytic operations, so there is more freedom in adjusting parameters while monitoring the process–but it’s also more demanding
When the liquid level in the re-refining tank is low, it indicates that either too much light diesel is being drawn off from the distillation tower, or the degree of reaction is too high, resulting in significant fluctuations. In response, the degree of reaction can be reduced, the amount of light diesel drawn off can be decreased, or the flow back to the distillation tower from the re-refining tank can be slowed down.
Temporarily reducing the operation of the reprocessing tower can help maintain the liquid level in the tank for a short period; this is mainly due to an increase in depth, and the key is for the reprocessing unit to reduce that depth