What causes a sudden rise in hydrogen-rich overhead gas?
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In this unit for the hydrogenation of high-temperature coal tar, in the second stage of the cracking unit, the hydrogen sulfide concentration suddenly dropped from 300 ppm to 130 ppm, while ammonia concentration suddenly increased from 100 ppm to 3000 ppm. Increasing the sulfur injection amount during cracking did not yield significant results; analysis showed that there were no major changes in the properties of the feed oil, nor any significant changes in the temperatures of the beds in the refining and cracking reactors. What are the reasons for the sudden increase in high-ammonia content in Stage 2, and what are the countermeasures? ?
Cold high? Has it been passivated due to cracking, causing the ammonia inside to precipitate suddenly? It’s just a guess
It seems that this possibility is a bit higher
Let’s start by considering the issue of catalysts.
It seems unlikely; the facility started operations in August 2018, and this situation only arose in February of this year
Has there been any significant change in the sulfur and nitrogen content of the crude oil? Also, has there been any change in the water injection volume? The possibility of passivated ammonia precipitating is low, after all, so much time has passed
The properties of the crude oil and the amount of water injected remain unchanged, and process parameters such as bed temperature also stay the same