Catalytic slurry yield

The efficiency of the cyclone will not be 100%; inevitably, some catalyst will make its way into the fractionation tower, where it is carried into the slurry by the washing section at the bottom of the catalytic fractionation tower. Therefore, the slurry needs to be removed periodically in order to eliminate the catalyst and keep its concentration below 6 ppm； There are many factors that affect the density of oil slurry; if the feed amount remains constant, the density is higher when operating at high temperatures in the distillation and washing stages, and lower otherwise. This to some extent reflects the degree to which light components are removed from the mixture. However, it is important to keep the temperature below 350–360 degrees, otherwise the oil slurry will deteriorate. For typical refining feedstocks, a density of around 1000 is appropriate ； \"External discharge\" can be simply understood as moving away from this unit to another unit or tank area, while \"reprocessing\" means returning to the lift pipe catalytic cracker in order to increase the conversion rate of the feedstock ； Upon further cracking, the cracking principle remains the same as that for feeding. Due to the heavier composition, with unchanged reaction and feeding temperatures as well as an unchanged catalyst-to-oil ratio, both the per-cycle and total coke formation rates increase; the yield of light oil per cycle decreases, while the total yield of light oil increases. The dry gas production increases, and the slurry production decreases

The density of the slurry is related to the properties of the feed oil and the extent of the catalytic cracking reaction; it is also connected to the control of the temperature of the saturated oil and gas in the washing section of the distillation tower. Generally, it is sufficient to keep the solid content in the slurry below 6 g/L. The level of solid content is due in part to the catalyst used for washing, as well as to highly polymerized gums. The amount of slurry that needs to be removed can be determined by taking into account factors such as the solid content and density of the slurry, as well as the long-term operation of the plant. A high content of aromatics, asphaltenes, and gums in the slurry leads to increased coking during reprocessing. In current heavy oil catalytic units, slurry reprocessing is rarely carried out; it is generally used when the temperature in the regenerator is low and there is insufficient heat in the plant, in order to increase coking and thus maintain the reaction temperature.

I mean, is the slurry yield determined by the process design or by the operating conditions of the plant’s hardware?

I mean, is the slurry yield determined by the process design or by the operating conditions of the plant’s hardware?

Taking both aspects into consideration, process design is the key

The answer is pretty good; that’s more or less it.

The density of the slurry is determined by the process (degree of cracking), while its solid content is determined by the equipment (efficiency of centrifugation). The slurry at the bottom of the distillation tower becomes more concentrated; whether it’s aromatics or catalyst particles, it depends on which one reaches its limit first…… The level of these values determines the amount of material that needs to be removed

Thank you. According to what you said, if the cyclone is in good condition, the slurry production rate should be mainly influenced by density. If the density is not high, then the level of slurry production can indicate the quality of the cyclone, right? That is, if the oil slurry yield of the process package is 5%, as long as the cyclone performs well and operations are carried out in accordance with the process design, then the solid content certainly won’t be high? I mean, if the process design calls for oil slurry yields of 5% and 2%, would that result in different requirements for the manufacture of the cyclones?