Analysis of causes of high olefin content in gasoline

Using straight-run oil as cooling gasoline should help reduce olefins. Is the amount of olefin reducing additive added enough?

High reaction temperature, decreased agent-to-oil ratio, and high air velocity may lead to high olefins. Check to see if the above reasons occur. In addition, using too little terminator may also lead to high olefins. It is also worth exploring whether hydrothermal damage to the catalyst structure leads to a decrease in selectivity and a higher level of olefins.

1. The increase in the ratio of catalyst to oil increases the number of catalyst particles in contact with unit hydrocarbon molecules, which not only promotes the cracking of raw materials, but also promotes the cracking of olefins in gasoline, resulting in a reduction in the olefin content of gasoline. 2. The catalyst activity increases, which intensifies the hydrogen transfer reaction and reduces the olefin content of gasoline. 3. The initial boiling point of gasoline increases, resulting in a shortening of the gasoline distillation range, resulting in a decrease in the low boiling point fraction of gasoline, resulting in a decrease in the olefin content of gasoline. 4. When the reaction temperature increases, the decomposition reaction (generating olefins) and aromatization reaction increase faster than the hydrogen transfer reaction, so the olefins and aromatic hydrocarbons content in gasoline increases. 5. The higher the equilibrium catalyst activity, the faster the catalytic cracking reaction speed; the acceleration of the catalytic cracking reaction speed weakens the thermal cracking reaction, thereby reducing the content of diolefins in gasoline. 6. The effect of hydrogen transfer reduces the olefins in gasoline. The reaction temperature increases, inhibiting the hydrogen transfer reaction, and the olefin content in gasoline increases. 7. Under the dual action of secondary cracking reaction and hydrogen transfer reaction, heavy olefins in gasoline are converted into propylene and isoparaffins, which greatly reduces the olefin content in gasoline. 8. Promote the hydrogen transfer reaction of olefins in gasoline and reduce the olefin content in gasoline. 9. The low reaction temperature inhibits the further cracking of small molecular hydrocarbons and is conducive to the occurrence of hydrogen transfer reaction, so the dry gas yield is reduced. 10. In order to reduce the olefin content of gasoline, measures should be taken to continue the reaction of the already generated gasoline fraction, and achieve effective conversion of olefin components in gasoline through the deep reaction of gasoline. 11. The increase in reaction temperature will intensify the weight of thermal cracking reaction in the cracking reaction, further worsen the selectivity of high-priced products, and reduce the ability of hydrogen transfer reaction, which is not conducive to the reduction of gasoline olefin content. 12. Thermal cracking reaction is an important source of olefins, especially diolefins. The reaction temperature increased by more than 10°C. This intensifies the cracking reaction and increases the chance of secondary cracking after the riser, which inevitably results in an increase in olefin content13 and an increase in reaction temperature. High reaction temperatures intensify thermal cracking and secondary cracking, increasing the content of a large amount of olefins, especially diolefins, which directly leads to a shortening of the gasoline induction period.

We analyzed the catalyst activity and found it was only 57. We replaced 20 tons of balancing agent and increased the processing capacity. The device is operating at full capacity. Now the olefin content of gasoline is gradually declining. Thank you all for your advice.

I don’t know which company you belong to, but judging from your storage capacity, your catalytic device processing capacity is only between 500,000 and 800,000 tons per year. 1. The total olefin content of the steam catalyst remains high. The reason lies in the choice of reaction conditions and the screening of the catalyst. If the first two conditions cannot be changed, the operation of the stabilizing tower is also the most important influencing factor. 2. If the olefin-reducing additive still cannot achieve the goal within the range recommended by the manufacturer, then it is necessary to consider adjusting the operation of the catalytic reaction position. 3. Adding direct steam as a terminator is very helpful in improving the olefin content. Straight-run oil contains mostly saturated hydrocarbons. I hope the above technical advice will be helpful to you in organizing your production. . . This post was last edited by wangsc on 2009-3-24 22:00 ]

Aren’t we developing olefin reduction catalysts now? If we consider replacing the catalyst, we may improve product distribution and product quality.