Questions about injecting terminator into catalytic cracking riser
Thread Content
When the reaction temperature is controlled at 500°C, the terminator is also injected. When the reaction temperature is controlled at 515°C, the terminator is also injected. If the amount of terminator, feed amount, bed temperature, etc. injected at this time are the same, then what is the difference between the two when the reaction temperature is different?
The injection of terminator is not determined solely by the reaction temperature, but also by the depth of the reaction.
How to adjust the reaction temperature by looking at the reaction depth?
Comprehensive judgment is required, e.g.: Coke production rate, oil yield rate of each product, liquid level in the refining oil tank, dry gas and liquefied gas yield, liquid level at the bottom of the fractionation tower, etc. ； A comprehensive analysis is required to decide
The analysis on the 2nd and 4th floors is correct. It is mainly due to changes in the reaction depth. The termination dose increases, the reaction depth increases, the catalyst circulation volume increases, the oil slurry yield decreases, the liquid level in the fractionation tower decreases, the gasoline yield increases, and the liquefied gas yield increases.
Okay~ Let’s put aside the analysis of reaction temperature control and other factors for now. If other conditions are constant, what will be the difference in reaction temperature when the same amount of terminator is added at different stages? Which terminator works better at different temperatures?
I think the riser should be divided into three sections. From the perspective of reaction time, one section is the pre-lift section (from the bottom of the riser to the raw material nozzle), the second section is the feed section (from the raw material nozzle to the terminator nozzle), and the third section is the secondary reaction section (the terminator nozzle to the riser outlet). The depth of the second reaction section should be considered based on the properties of the raw materials, and the reaction depth can be seen through the change in liquid level in the fractionating tower and the distribution of the product. When the same amount of terminator is injected, the reaction outlet temperature will be different. The higher the outlet temperature, the greater the reaction depth in the second-stage reaction zone.
The function of the terminator is to terminate the secondary reaction of oil and gas and reduce coking and gas generation.
Terminator technology has been developed in recent years. Its main purpose is to reduce the secondary reaction of reacting oil and gas, which can effectively inhibit the production of olefins.
When it is necessary to inject a terminator, of course, the sooner the better, early detection and early treatment, so this is a matter of experience and requires constant exploration. As someone above said, analyze and judge from different angles.
The reaction depth and cracking reaction requirements generally have an optimized value, haha
The purpose of the terminator is to increase the agent-to-oil ratio and increase the reaction depth to a certain extent.
The terminator mainly uses crude gas oil, and its main purpose is to quickly cool and reduce secondary reactions.
The terminator is introduced to increase the reaction temperature and depth of reaction while ensuring that secondary reactions are minimized at the exit of the riser. On the other hand, a certain reaction temperature must be ensured to balance the heat in the entire fractionation tower. A large termination dose indicates a greater depth of reaction.
If you observe carefully enough, you will find that after the terminator is injected, the valve opening becomes larger, which means the reaction depth deepens under the same conditions. If other conditions remain unchanged, there will be small changes in bed temperature and dry gas production. No obvious effect can be seen in liquid collection. But it is still beneficial to settler coking. Only the gas phase load of fractionation will increase.