Problems in the thermal balance calculation of catalytic regeneration
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When performing thermal balance calculations for regenerators, is the heat generated by the temperature rise of coke taken into account? Although it accounts for less than 0.5% of the heat released during coke combustion. Also, how does everyone calculate the heat loss of the regenerator? Some say 139 kca/kg of coke, while others say 5-7% of the calorific value of coke. The difference is quite large, about half. When calculating the total air volume, should pressurized air, non-purified make-up air, as well as air for loosening or backwashing, etc., also be included? Please share your opinions.
Based on my previous calibration, here are the details: 1. Heat generated by the temperature rise of coke: This has not been taken into account (it should be calculated; this will be improved in the next iteration). 2. Heat loss in the regenerator: Calculated based on the surface area and heat transfer coefficient. 3. Total air volume: Of course, the pressurized air needs to be included (in our case, it is calculated using the total flow rate at the main air inlet). 4. We have not calculated the heat associated with the unpurified air and backwashing air (this can also be calculated using the data from orifice plates; this will be improved in the next iteration). Additional note: We have calculated the heat absorbed by steam, based on the amount of steam entering the regenerator as determined by the orifice plates
Is the heat carried by external and internal extraction not taken into account?
Reply to 3# liaifeng: Of course it needs to be calculated, based on the steam generation volume. We also need to take into account the heat loss from the external heat exchanger :D
The post only mentions the points that are unclear. As for heat extraction from the outside, of course it needs to be calculated. How much do the values obtained by each device differ, based on the calculated amount of charring and the results from material balance? Also, there is a significant difference between the flue gas components based on online analysis and those obtained from sampling results.
Reply to 5# zzh030972: The amount of burning is calculated based on flue gas analysis; it’s not possible to calculate it using material balance, as it’s unknown how much was lost during processing. Flue gas analysis relies on sample results
If the amount of charring is determined through calculation, what is the final loss resulting from that? It’s within a reasonable range I guess; there’s a significant difference between the results of smoke sampling analysis and those of online analysis, and the gap here is quite large. You know, which method should be used for calculation?
Reply to 7# zzh030972: It’s really difficult to calculate. We also referred to the data from normal operations in order to estimate the processing losses. Moreover, the coke yield obtained from flue gas sampling is not very good either, as production is dynamic – how can a single flue gas analysis ensure that the coke formation rate remains constant?