Reasons for the low octane number of the reformed product oil or low aromatic yield

The first is to pay attention to the potential aromatic content in the feedstock used for reforming; this can be determined through testing. A low value indicates that the octane number or aromatic content of the oil produced as a result of reforming will be low； The second aspect is to focus on the activity of the catalyst; the regeneration activity of the catalyst directly affects the octane number and aromatic content of the reformed oil. The reforming catalyst is a dual-activity catalyst, with both metallic activity and acidic sites contributing to an increase in the aromatic content of the produced oil. The catalyst’s activity can be determined from the overall reaction temperature and the aromatic content value ； The third point is to focus on whether the reaction temperature is low when the air velocity remains constant ； The fourth concern is whether the impurity levels in the feedstock used for reformation are above acceptable limits, especially sulfur and nitrogen contents. Sulfur poisoning of the catalyst reduces its metal activity, while nitrogen poisoning reduces the activity of its acidic sites ； The fifth concern is the dry point of the reforming feed; a high dry point of the reforming feed can lead to increased catalyst coking, which affects the catalyst’s activity and reduces the octane number and aromatic content of the oil produced through reforming ； The sixth point of concern is the control of the sulfur injection amount during feed reforming. Generally, after catalyst regeneration, its activity is high at the beginning of the first reaction stage; if this activity is not suppressed, carbon deposition will occur rapidly on the catalyst, which is why sulfur injection is necessary. However, improper control of the sulfur injection amount can have the opposite effect.

Root cause: The reformation raw materials determine the product.

This post was last edited by will_lin on 2009-9-25 at 22:30. Three main points are of concern: 1. Reaction temperature – this is generally not the primary cause; if the problem persists even at 510 degrees, other causes should be explored. 2. Feed quality – aromatic potential needs to be analyzed carefully; if it is too low, the composition of the raw materials or the pre-hydrogenation process must be adjusted. 3. Catalyst performance – this is assessed by examining the temperature drop in the reactor, and comparing it with the data from normal production conditions. If it is confirmed to be a catalyst issue, then analyze the specific reasons. Generally speaking, except for permanent poisoning, all issues can be resolved through regeneration systems as well as the addition of sulfur and chlorine.

The raw materials are generally hydrogenated coker naphtha and straight-run naphtha. Hydrogenated coker naphtha has a relatively low aromatic potential; therefore, the higher its blending ratio, the lower the octane number produced. Additionally, factors such as temperature, water-chlorine balance, and catalyst activity also play a role

Could you explain the reasons for the low reforming conversion rate? And processing? Thank you!

I wonder, OP, why you asked this question. If it’s purely to learn* and acquire knowledge, then take your time; one can learn something from everyone’s replies. If there is indeed a problem, such as a sudden drop in octane level recently, then it needs to be analyzed carefully, and this can be done from three perspectives. 1. Raw materials (including aromatic compounds and impurities); many people upstairs have already explained this ； 2. Reaction conditions (space velocity, temperature; the catalyst is also included here), as someone else mentioned upstairs ； 3. Check the equipment to determine whether there is a leak into the feed heat exchanger. However, if the octane number is too low, based on my analysis, the possible issues are either catalyst poisoning or a leak in the feed heat exchanger; other factors could also affect the results, but these can be addressed by adjusting operations, thereby preventing the octane number from dropping too low.