How to deal with salt deposition in the reformation feed heat exchanger?
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The continuous reforming unit in our facility has recently experienced this issue: with no changes in feed rate, reaction temperature, or other operating parameters, the outlet flow rate of the reforming cycle hydrogen compressor decreased from 35,000 Nm3/H to 22,000 Nm3/H, while the pressure at the compressor outlet increased. It is suspected that salt deposition in the reforming feed heat exchanger is the cause. Has anyone encountered such a situation before? How was it handled? Thank you all for your advice!
I’ve never encountered it, but I remember reading that it’s better to clean it with a weakly alkaline hydrazine solution
Is the poster referring to the plate heat exchanger for feeding? The pressure drop is very small; one can observe the changes in the pressure drop at the inlet and outlet of the heat exchanger to determine whether salt has accumulated on it, but I personally think the possibility is low. :L
Are the reactor pressure drops normal? It is recommended that the poster have DCS footage
It’s not necessarily salt formation! It could be that coking blockage is causing an increase in pressure difference
The pre-hydrogenation section of the reforming unit is prone to salt formation, which is why a water injection line is usually provided. The feed oil used in the reforming reaction section has very low levels of sulfur and nitrogen, so the likelihood of salt formation in the heat exchangers should be low
There is such a possibility; assuming there are no issues with the compressor itself, it is necessary to judge based on key parameters such as the pressure drop across the filter on the DCS display.
Personally, I don’t think the possibility of salt formation in the plate exchanger is high. Firstly, the impurities in the reforming feed are very low; secondly, salt formation should occur over a certain period of time, so it’s unlikely that salt formation could cause a significant decrease in the amount of circulating hydrogen in such a short time； Problems with the reactor internals or catalyst coking and blockage of the Johnson screen can all lead to an increase in system pressure drop.