Blockage issue in the leg of the settler centrifuge

1. Bring the leg pressure drop back to zero and draw a straight line. 2. The solid content of the slurry increases sharply. Immediate emergency shutdown is required.

This post was last edited by Jubao Pen Yi on 2019-1-20 09:33. Assessment: 1. The pressure drop in the collector chamber at the top of the settler has decreased. 2. The solid content of the slurry increases. Processing: 1. If the phenomenon is not severe, it indicates that only a single material has suffered coking, which does not affect normal production; the pressure drop in the collector chamber at the top of the settler can be controlled by adjusting the feed rate, the settler pressure, and the amount of steam injected into the reactor. 2. Increase the amount of slurry discharged to control its solid content. Some flushing oil can also be injected into the slurry heat exchanger to prevent catalyst deposition, coking, and blockages, thereby ensuring normal circulation in the slurry system. 3. In the event of a sharp increase in the solid content of the slurry, an emergency shutdown shall be initiated. Generally, a blockage caused by the material on one side only does not affect production, so there is no need for an emergency shutdown.

First, it is necessary to determine whether there is a blockage. When the feed leg is blocked, the solid content of the slurry increases; we only examine whether this is the cause when trying to find the reason. If there is indeed a blockage, and we usually have several feed legs, we consider the level of solid content – if it is truly very high, then an emergency shutdown is required

The possibility of coking in the material legs is not zero, but it is relatively low. If the raw materials are too heavy or of poor quality, there is a higher likelihood of coking occurring in the dome of the reaction settler, the external gas collection chamber, and even large oil and gas pipes – such cases have already occurred before. If the material leg becomes blocked, it is more likely that the manhole was sealed without checking whether it was unobstructed after maintenance, resulting in a large amount of catalyst flowing into the distillation tower once it was opened again; such accidents have occurred before as well. It must be emphasized that the introduction of a large amount of catalyst into the slurry system is very dangerous; it can quickly cause the slurry to lose its fluidity, leading to blockages in the entire slurry circulation system, which in turn requires shutting down operations and cutting the pipelines – and there are precedents for this. Therefore, in such a situation one must not be careless; it is necessary to stop the feed as soon as possible, transfer all the catalyst to the regenerator, and then shut down the system for maintenance.

1. The pressure drop during fine spinning decreases, while the pressure drop during coarse spinning increases; there is also leakage from the settler. 2. The solid content of the slurry increases significantly. Solutions: 1. These fluctuations are caused by human intervention, which disrupts the balance; it is necessary to determine whether it is possible to restore normal operation. 2. Determine whether to carry out emergency repairs based on the condition of the running agent