The operating principle of heavy oil catalytic cracking is how to understand hydrogen transfer reactions

1. Principles for accelerating reaction operations: The reaction unit is a key part of this facility, and it has a significant impact on production. Therefore, the operator in this position must ensure smooth operation, as well as maintain balance in materials, pressure, coking and burning processes, and heat. Achieve high quality, high yield, low consumption, and safety without accidents ； It is necessary to carefully observe any changes in operations, analyze them calmly, take decisive action, and nip accidents in the bud. It can be used promptly and accurately when necessary; in the event of an accident with the device, the following principles must be followed. 1.1 In the event of pressure fluctuations or catalyst backflow, the reserves in the two vessels must not be emptied at each other’s expense; otherwise, oil and gas may mix with air, leading to severe explosion accidents. If this situation cannot be controlled, immediately activate the reserve protection system, close the standby and regeneration valve, and cut off the feed to the reactor. 1.2 Except in the event of a major power outage, as long as there is catalyst in the reaction and regeneration systems, a fluidizing medium must be introduced, including both stripping and loosening media; otherwise, dead beds and blockages will occur. 1.3 The exit temperature of the lift pipe shall not exceed 600°C, and the temperature of the regenerator shall not be higher than 750°C. In case of overheating, cooling media such as emergency steam, dilute-phase water spray, cooling steam, and cooling gasoline should be introduced promptly, and effective measures should be taken immediately to prevent equipment damage or seizure. 1.4 Under riser feed conditions, its outlet temperature must not be lower than 460°C; otherwise, the feed should be shut off. 1.5 In the event of an accident, the temperature of the regenerator bed should be maintained above 440°C as much as possible; if necessary, the main air heater should be activated. If the temperature of the regenerator bed drops below 300°C, the catalyst must be removed immediately and operations stopped to prevent caking of the catalyst. Under special circumstances, with the approval of the relevant superiors, it may be possible to avoid removing the catalyst, but it is essential to ensure that no steam is introduced to prevent caking. 1.6 When the regenerator uses steam fluidization, the injection of combustion oil must be stopped. 1.7 During accident handling, follow the unified instructions of the shift leader and pay attention to the impact on relevant positions. And carry out contact efforts in a timely manner to strive to minimize the consequences of the accident and create conditions for restoring normal operations as soon as possible. 1.8 Hold effective post-shift meetings, carefully summarize experiences and lessons learned, and keep detailed records. 2. Hydrogen transfer reaction: Cycloalkanes or alkanes–arenes release hydrogen, causing the olefins to become saturated while they themselves gradually transform into polycyclic arenes, or even condense into coke. Hydrogen transfer reactions can occur between two olefin molecules; for example, a hydrogen transfer reaction between two hexene molecules results in one molecule becoming hexane and the other becoming hexadiene. It can be seen that the result of the hydrogen transfer reaction is that, on the one hand, certain olefins are converted into alkanes, while on the other hand, the compounds that donate hydrogen are converted into aromatics or condensed into molecules with a higher degree of synthesis.

High temperature and short contact time, along with a high oil-to-sludge ratio, contribute to increased gasoline production and higher processing capacity

A hydrogen transfer reaction is a reaction in which a hydrogen atom from one hydrocarbon molecule is removed and added to another alkene molecule, thereby saturating that alkene molecule. Hydrogen transfer is a reaction unique to catalytic cracking; it proceeds at a relatively fast rate, and cycloalkanes with side chains are the main source of hydrogen. Hydrogen transfer is different from ordinary dehydrogenation and hydrogenation reactions involving hydrogen molecules; it involves the transfer of active hydrogen atoms from one hydrocarbon molecule to another, thereby saturating olefins, converting dienes into monoolefins or saturated hydrocarbons, and changing cycloalkanes into cycloolefins which then turn into aromatics, thus improving the stability of the products. The result of the hydrogen transfer reaction is that, on one hand, certain olefins are converted into alkanes, while on the other hand, the compounds that provide hydrogen are transformed into aromatics and condensed into larger molecules or even coked, thereby increasing the coking rate. The hydrogen transfer reaction is an exothermic reaction that requires a highly active catalyst and a low reaction temperature to achieve a higher reaction rate.

*e Thank you. Agree with the person above. . 01. Hydrogen transfer reactions can occur between two olefin molecules; for example, a hydrogen transfer reaction between two hexene molecules results in one molecule becoming hexane and the other becoming hexadiene. It can be seen that the result of the hydrogen transfer reaction is that certain olefins are converted into alkanes; this requires lowering the reaction temperature and increasing the catalyst activity. Hydrogen-producing compounds are converted into aromatics and condensed into larger molecules or even coked, thereby increasing the coke formation rate