What is the reprocessing ratio? What is the impact of the recycle ratio on the operation of a catalytic cracking unit?

As pressure increases, the boiling point of the oil rises; to achieve the same rate of vaporization, a higher inlet temperature is required, resulting in the lighter components moving downward. The reprocessing ratio is the ratio of the amount of slurry sent back to the riser for reprocessing plus the amount of reprocessed oil, to the amount of fresh feedstock. The diesel yield increases, and the coke production increases.

Refining ratio = Total amount of refined oil (t/h) / Amount of fresh feed oil (t/h) = Total conversion rate / Single-pass conversion rate – 1; here, the total amount of refined oil refers to the sum of the refined oil and the refined oil slurry. The reprocessing ratio is not an independent variable; at a certain overall conversion rate, it merely reflects the one-pass conversion rate. With a high one-way conversion rate, the reprocessing ratio is low. The recycle ratio is an important indicator in catalytic cracking reactions; it is closely related to the yield distribution of the products, product quality, the thermal balance of the plant, and the plant’s processing capacity. (1) As the one-pass conversion rate increases, the ratio of diesel yield to one-pass conversion rate decreases rapidly. Therefore, to increase the diesel yield, the one-pass conversion rate should be reduced and the reprocessing ratio increased. In this way, on the one hand, the reaction depth is shallower, making it difficult for diesel to undergo secondary cracking ； On the other hand, an increase in the reprocessing ratio reduces the partial pressure of diesel produced by catalytic refining, thereby further decreasing the degree of secondary cracking of diesel. (2) Reducing the one-way conversion rate and increasing the re-refining ratio can lower the freezing point of light diesel and increase its cetane number. (3) After the reprocessing ratio increases, the heat required for the reaction **increases**, and as a result, the load on the raw material preheating furnace, as well as the loads on the reactor and distillation tower, also increase. As the heat required for the reaction increases, this in turn leads to a decrease in the regeneration temperature and an increase in the carbon content of the regenerated catalyst, further reducing the degree of conversion per pass; sometimes it is necessary to reduce the processing volume or the production of diesel in order to lower the reprocessing ratio. Therefore, the increase in the reprocessing ratio is limited

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Refining ratio = Total amount of oil reprocessed (t/h) / Amount of fresh feed oil (t/h) = Total conversion rate / Single-pass conversion rate – 1. Here, the total amount of oil reprocessed refers to the sum of the reprocessed oil and the reprocessed slurry. The refining ratio is determined based on the properties of the feed oil and the activity of the catalyst; each case must be analyzed individually. If the feedstock is light, the reprocessing ratio can be increased appropriately, as well as the ratio of additive to oil, in order to achieve a higher yield. If the feedstock is heavy, a high reprocessing ratio may lead to coking and burning issues in the regeneration system; moreover, the increased specific gravity may cause problems in the oil slurry lines of the distillation system, result in reduced flow in those lines, an increase in the amount of dry gas, and thus an increased load on the compressors. Therefore, it is necessary to analyze each situation individually

Is \"Q&A on Catalytic Cracking Technology\" this book? Or a forum section?

Catalytic Cracking Technology Q&A, 2nd Edition, 50 yuan

40 yuan – a colleague of mine bought it for less than 30, and that doesn’t even include shipping costs, which are 40!

This post was last edited by dentrode on 2011-12-5 at 15:49. Is it this book, Technical Questions and Answers on Catalytic Cracking Units (2nd Edition) by Ma Bowen, published by Sinopec Press? Technical Q&A on Catalytic Cracking Units (2nd Edition) (Ma Bowen, Sinopec Press)

Refining ratio = Total amount of refined oil (t/h) / Amount of fresh feed oil (t/h) = Total conversion rate / Single-pass conversion rate – 1. Here, the total amount of refined oil refers to the sum of the refined oil and the refined oil slurry. The refining ratio is not an independent variable; at a given total conversion rate, it merely reflects the single-pass conversion rate. With a high one-way conversion rate, the reprocessing ratio is low. Generally, when the reprocessing ratio is high, the amount of coke produced in the reverse regeneration system increases significantly, which is beneficial for increasing diesel production