[Weekly Topic] Does the properties of catalysts affect coking in settlers?

It can be said that there is a direct relationship: catalytic cracking catalysts tend to accumulate carbon, which leads to coking in the settler

Here’s my personal opinion: I think the \"coking\" in the settler consists of two components: one is the end product of catalytic cracking – coke; the other is the condensation of heavy fractions. The amount of coking in both of these components is related to the properties of the catalyst (and, of course, to other factors such as temperature as well). The ideal operating condition is one in which factors such as the catalyst’s activation temperature allow it to avoid the formation of coke and heavy fractions. Additionally, it’s also a great idea that the new process eliminates the settler.

Catalyst damage has an impact on coking in the settler. Most of the coking in the settler consists of fine catalyst powder; after removing the catalyst, the hydrogen content in the coke is about 3%-4% (by mass). Pyrolysis is the result of the condensation and thermal cracking reactions of large-molecule polycyclic aromatic hydrocarbons.

Brother upstairs, catalytic cracking uses a fluidized bed and does not require ceramic balls for filling; you’d better look into fixed-bed systems instead

Reply to 6# Chu Mingfeng: Coking in the catalyst pre-sedimentator has an impact; at the same reaction depth, a higher capacity of the catalyst for converting heavy oil plays a significant role in slowing down coking. Therefore, re-pressurization requires a high oil ratio.

Catalysts have various properties, and each of them affects coking in settlers. Please correct any inaccuracies: 1. Activity – A catalyst with high activity (dynamic activity) possesses strong capacity to convert heavy oil; it can effectively reduce the presence of large molecular substances in the feedstock, thereby minimizing the formation of \"liquid coke\" and reducing coking in settlers and oil-gas lines. 2. Selectivity: A catalyst with good selectivity results in a favorable product distribution. If the oil slurry is not the desired product of catalysis, this means that the levels of oil slurry and other heavier fractions will decrease, which can affect coking in the settler. 3. Pore size distribution: As the properties of the catalytic feedstock change, the pore size of the catalyst increases compared to before; this is done to enhance the ability to convert large molecules and to reduce coking in the settler. 4. Ability to resist heavy metal contamination: The deterioration of catalytic raw materials and the increase in the content of certain heavy metals reduce the catalyst’s activity and selectivity, leading to poor product distribution, a decreased capacity for converting heavy oils, and impacts on coking in sedimentators. 5. Hydrothermal stability: With the improvement in catalyst manufacturing techniques, the hydrothermal stability of current catalysts is generally good, sufficient to meet the requirements of catalytic applications. 6. Wear resistance index: A low wear resistance index of the catalyst, along with a high amount of fine catalyst particles, can have a significant impact on coking in the bottom of the fractionation tower and in heat exchangers, especially if process control is inadequate. 7. Catalyst particle size distribution, density, etc.: If these properties affect the fluidization of the catalyst, it will in turn affect the catalyst-to-oil ratio; this reduces the capacity to convert heavy oils and can also lead to coking in the settler. There are many factors that affect coking in settlers, and it is a systematic issue. With the advancements in catalytic cracking technology in recent years, measures to prevent coking have been continuously improved, resulting in a significant reduction in coking in settlers (as shown by data), which has had a positive impact on the long-term operation of catalysts.

It can be said that there is a direct relationship with reaction conditions, transportation, etc. Activity, etc., are all related

The properties of the catalyst have an impact on coking in the settler. The reasons are as follows: coking in settlers occurs in two types, namely hard coke and soft coke. Hard coke contains a small amount of catalyst fine powder, while soft coke contains a large amount of catalyst fine powder. The formation mechanism is as follows: the hydrocarbon stream resulting from catalytic cracking contains large amounts of heavy aromatic compounds, gums, asphaltenes, and other heavy components, which undergo condensation reactions at high temperatures to form coke. From the perspective of catalysts, there are two ways to reduce or avoid coking in settlers: one is to select appropriate catalysts with enhanced activity and strong cracking capacity, in order to reduce the amount of heavy components ； Second, the particle size composition of the catalyst should be properly adjusted to ensure proper fluidization; catalyst breakdown should be avoided during operation, and the catalyst should be removed promptly and replaced with fresh catalyst.

Coking in the catalyst pre-sedimenter has an impact; the catalyst pre-lifting effect is poor, resulting in inadequate mixing between the catalyst and the feedstock. Solution: Choose catalysts with good heavy oil cracking performance, high selectivity, and strong resistance to metal contamination ；

Reply to 10# sun-rock: So, what are the ways to solve soft focus?