The methane content in the hydrogen from semi-regenerative reforming is relatively high
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Equipment: Semi-regenerative reforming. Recently, the methane content in the recycled hydrogen has reached levels between 10 and 12, while the C3 content is above 3; the purity of the recycled hydrogen is only between 75 and 77. What’s causing this?
It’s possible that there are too many ether compounds in the naphtha feedstock (such as MTBE); we’ve encountered this issue here, so we need to conduct an analysis to confirm it
After pre-hydrogenation of naphtha, ether compounds should no longer be present; they should be converted into water and removed during the distillation process
Based solely on the hydrogen composition, it can be determined that the metal functionality is too strong, with no sulfur present
The catalyst has been in use for over a year and is now at the end of its life. Could it be that the carbon deposits on the catalyst have shifted to the acidic functional sites, while the carbon deposits on the metal functional sites have been removed?
It is regarded as pre-hydrogenation cycle hydrogen. An excessive amount of ethers in the naphtha feedstock can lead to a high methane content in the hydrogen used in the pre-hydrogenation process. There’s no problem with the reforming feed; however, there is an excess of methane in the reforming cycle hydrogen. This suggests that the hydrodesorption reaction is occurring quite intensely. Hydrodesorption is an exothermic reaction, and its occurrence leads to a drop in reaction temperature. Are such phenomena observed? The sulfidation of the other half of the regenerated platinum-rhodium catalyst was carried out in order to reduce the activity of the fresh catalyst and prevent intense hydrolysis reactions; currently, this situation may be caused by excessive activity. I’ve never been involved in semi-reforming processes; it’s just my own speculation :)
It is also possible that the system is too dry; currently, about 2.5 ppm of water is added, along with about 2.5 ppm of chlorine. However, the analysis shows no change in the water content in the gas before and after the addition of water (it is assumed for now that the analysis results are inaccurate)
It is likely that the acidic function has weakened, resulting in a stronger metallic function and an intensified demethylation reaction.