Does a prereformer require an automated bypass? Some catalyst vendors insist on auto bypass; some say it is not required. What is best practice?
Answers
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12/02/2012
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Raghu Raj Singh, IOCL Haldia Refinery, singhrr@indianoil.in
In Linde hydrogen plant bypass of pre-reformer is provided along with inlet and outlet shutdown valve as after tripping of plant pre-reformer is purged by steam only by 10 minutes. After purging by steam bypass shutdown valve opened and inlet and outlet shutdown valve closed. While in Haldor Topsoe plant 30 minutes of purging is done of whole circuit of of pre-reformer and reformer by steam and hydrogen and not required any bypass as hydrogen is also going along with steam while in Linde hydrogen plant hydrogen facility for purging is not given so pre-reformer bypass SDV is required like Haldor Topsoe Shift reactor system to avoid capillary condensation.
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31/03/2011
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Syamantak Dhar, Indian Oil corporation Limited, syamantak.dhar@aol.in
Are you sure you are asking for an automated bypass for an Pre-Reformer, basically it is kind of weird in case of Hydrogen plants using naphtha as a feedstock or in case of natural gas feedstock having 2 steam mixing points. The main problem would be in the Reformer (for naphtha based plants) as it will lead to slippage of heavier hydrocarbons to the downstream section and cause coking there. Some plants specifically for this reason have 2 layers of catalyst in the reformer in order to take of slight slippage of heavier hydrocarbons in case of end of catalyst life for Pre-Reformer. But that case is limited by T'Put.
Suggesting an automated bypass of the shift reactor might be the question you are asking and in that case I would personally prefer that as it limits the possibility of capillary condensation inside the reactors.
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