Oil washing consumption issue
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Currently, washing oil serves as an important consumable in the benzene washing process; what is the typical annual consumption amount? How often needs the cleaning oil to be replaced, and what is the average annual total cost?
This issue is quite complex; it varies from one factory to another. There are many factors that influence consumption, such as the quality of the newly washed oil, operating procedures, the quality of gas, and individual factors – with the first three having a significant impact. As for the issue of replacing the washing oil, it depends on the quality of the circulating washing oil and the effectiveness of your benzene washing process. If the performance isn’t too poor, simply intensifying the regeneration process will suffice; if it has a significant impact on benzene washing, then it’s necessary to weigh the costs associated with oil replacement against the product recovery rate. It is recommended to carry out the replacement in a centralized manner when this situation occurs; this not only ensures an effective removal of benzene but also simplifies the process significantly.
The oil consumption varies from one plant to another; currently, it is as low as a little over 30 kg per ton of crude benzene, while it can reach over 100 kg per ton of crude benzene in some cases； In my opinion, the factors that affect the consumption of cleaning oil are as follows: 1. The quality of the new oil; lower-quality oil leads to greater consumption ； 2. The quality of gas purification is poor, resulting in the highest amount of impurities being introduced into the circulating washing oil, which accelerates the aging of the washing oil ； 3. Temperatures of the debenzing tower and regeneration tower; if these temperatures are high, the washing oil tends to age more easily ； 4. Additionally, the mist capture efficiency of the benzene washing tower is poor, resulting in a large amount of washing oil being carried away by the gas.
In our plant’s crude benzene processing process, dilute slag is discharged; 70 Kg of washing oil is consumed per ton of benzene. To reduce this consumption, the slag discharge frequency and amount are determined based on the distillation yield at 300 degrees from the regenerator, and the washing oil carried in the gas coming from the benzene washing tower is recovered.
The costs are all very high. Is there any good solution?