Coking in catalytic cracking units
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Before installing the catalytic cracking unit, the yield was low and the amount of coke produced was high, although the bed temperature was not high. Recently, the yield has increased while the amount of coke produced is lower, but the bed temperature remains high. Some time ago, nitrogen oxides levels were low in flue gas desulfurization, but they have been higher recently. Some time ago, the ammonia nitrogen level in the flue gas desulfurization wastewater was high, but it is lower now. Dear sea friends, what’s going on here? Under what circumstances does this happen?
It should be directly related to the heat removed and the residual carbon in the raw materials. Try reducing the amount of heat removed; this way, burning will occur more properly and the level of charring will be lower.
Has the carbon content of the regenerant been analyzed to determine the coking effect? Could a high amount of coke formation along with low bed temperature indicate a carbon accumulation phenomenon?
1 Changes in the properties of the raw materials, 2 Changes in the amount of reprocessing, 3 Changes in regeneration temperature and thus changes in heat absorption, 4 Changes in the catalyst circulation rate, 5 Changes in catalyst inventory and activity. Check to see what changes are having an impact.
The carbon content is around 0.03; the lean phase in the regenerator is probably 3 to 5 degrees higher
By adding a denitration agent, the residual carbon remains basically stable