Calculation of water content in catalytic cracking regeneration flue gas

Basically correct; if a precise calculation is to be made, loose materials and purge steam (including those in the flue gas pipes and waste heat boilers, as well as at sampling points, etc.) must be taken into account, and a small amount that is carried along with the regenerated catalyst to the lift column must also be deducted. If the regeneration mode is oxygen-deficient regeneration (or incomplete regeneration), it is also necessary to consider whether the carbon monoxide burner (or carbon monoxide boiler) requires make-up combustion. If the goal is to reduce the H2O content in flue gas, the amount of water evaporated during the flue gas desulfurization process also needs to be taken into account. In fact, it is the saturated carrying capacity at the flue gas temperature.

Thank you, brother, for your answer! Our plant’s waste heat boilers now come equipped with denitration reactors, and the denitration catalysts have very strict requirements regarding water content. That’s why I want to do a rough calculation; do you think my approach is correct? ①Based on the local air relative humidity at 20°C, the water content in the air is approximately 2.15% (V/V). ② For charring, a value of 6% is used; based on the amount of material processed through catalysis and the main airflow, the water generated amounts to 5.6% (V/V). ③ In the denitration catalyst, reduction reactions occur; based on the inlet NOx levels, the minimum molecular weight compound NO2 is considered, resulting in 0.07% (V/V) of water being generated. ④ For other factors, an estimated value of 0.04% (V/V) is used. The water content in the flue gas before entering the denitration reactor is approximately 7.87% (V/V). Do you think these figures are reliable? ? ? Thank you!

The key factors are the coking rate and the H content in the coke; these two parameters are crucial and have a significant impact~~~

Loose steam and accident steam bypass orifice plates should also be included to make the calculations more complete. Is the H content in coke an estimate?

The char formation rate is calculated at 8%, with a H content of 6%! It should be more or less the same!

Steam and such are all included in the estimate to come up with an approximate value; H is an estimate. Do you have any practical experience in this area?

Your estimate might be on the high side; the normal theoretical value is around 7-8%. Our measurements show that the volume percentage of water vapor in the regenerated flue gas ranges from 3-5%, with lower values for those arranged side by side and slightly higher values for those arranged coaxially.

You can try to calculate the hydrogen content in coke, based on the results of the H-balance calculation

With proper stripping, H=6%; under normal conditions, H=7-8%. The yield of coke varies greatly and is influenced by factors such as the properties of the raw materials, the catalyst, the reaction temperature, and the efficiency of stripping. It can be calculated back using material balance, heat balance, H balance, etc., which makes it somewhat complex

We haven’t calculated this one yet. The calculation of charring degree requires accurate various data in order to obtain precise results; it is necessary to ensure the accuracy of both the instrument readings and the laboratory test data