Control of feed oil preheating temperature in catalytic unit
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This post was last edited by Refiner on 2018-2-13 at 14:58. What temperature should be used for preheating the feed oil in the catalytic unit? We currently use 220 degrees; what temperature do you use, and what is the basis for that?
Writing it this way can easily lead to the misunderstanding that it refers to the exit temperature of the lift pipe... The more standard term is the preheating temperature of the feed oil! Previously, in order to increase the steam output of the slurry boiler and reduce the energy consumption of the plant, it was proposed to aim for the lower limit of the specified values; I recall that we once set it as low as 180, with the upper limit being 240. I also observed these two values carefully, and found that the difference in steam production was around 2 T/H! The latest approach is to aim for the upper limit of the specified values, reduce the temperature difference between the regenerated catalyst and the feed oil, improve the product distribution, and lower the yields of dry gas and coke! What I actually want to say is that the data should be determined based on the actual conditions of the equipment, and extreme measures should be avoided. Sometimes, when the quality of the crude oil is good, there is no need to set the preheating temperature at its maximum value. Moreover, as the raw materials used in catalysis become more diverse, it is essential to control the temperature properly!
220 degrees is the normal cracking range; adjustments can be made based on the properties of the raw materials and the desired product profile. Generally, the cracking temperature is not used as a primary means for making adjustments, as the preheating temperature remains fixed depending on the properties of the raw materials.
It is generally kept between 220°C and 240°C.
The preheating temperature of the crude oil should not be too high nor too low; too low a temperature affects the atomization effect. Generally, it is necessary to ensure that the dynamic viscosity of the crude oil at this preheating temperature is no higher than 5 centistokes. However, the temperature should not be too high either, as this can cause the passivator to decompose easily
How can we ensure that the dynamic viscosity of crude oil at the preheating temperature is no higher than 5 Re?
Our preheating temperature is 205 degrees – is that a bit low?
It is a bit low. What is the quality of the raw materials you use? Is slag mixed in?
Are you deliberately controlling this temperature, or are you unable to do so?
The temperature should not be too high nor too low; it is necessary to maintain the reaction temperature and the temperature at the outlet of the lift pipe, taking into account various factors such as the amount of coke formed