Seeking help regarding desulfurization tower issues
Thread Content
The sulfur content in the hydrocracking feedstock used in our unit has remained around 2%. The reason why the hydrogen sulfide level in the recycle hydrogen after desulfurization is currently low, at around 200–300 PPM, is that we require this level to be between 500–700 PPM. As a result, the amount of amine solution (30%) used has been gradually reduced from 107 tons to around 100 tons. I would like to know why this is happening – the total sulfur content hasn’t changed much, and the feed volume has increased by 20 tons; so where has the sulfur gone? Recently, there have been no significant fluctuations in temperature and pressure at the high and low levels; (I haven’t paid much attention to the sulfur content in the acidic water.) Thank you all for helping to provide answers
Have fresh amine solutions been replenished recently? Check if the acidic gas coming from the top of the rich amine liquid regeneration tower has increased
I think we should first verify whether the analysis results are correct, as the concentration error at the ppm level is quite large. If it is still desired to increase the post-drying hydrogen sulfide concentration, in addition to reducing the solvent ratio, considering lowering the amine solution concentration can also achieve this goal while reducing the risk of foaming.
The results provided by the current laboratory technicians are for reference only; our facility has the final say
For hydrocracking, if sufficient sulfur is available in the feedstock, there is no need to keep the hydrogen sulfide concentration after desulfurization at such a high level; it does not have to be above 500. In actual production, a level below 100 is also acceptable. There is no need to worry about catalyst reduction, as the hydrogen sulfide concentration before desulfurization is high enough. The key thing is to remember to stop the amine-poor liquid pump when shutting down the process (or stopping the feedstock supply); there is enough hydrogen sulfide in the system. This is for reference only!