Ways to prevent pump-around heat exchanger fouling and extend run lengths on a benzene hydrogenation unit

A system for liquid phase hydrogenation, the system comprising:

• a hydrogenation reactor operable with a liquid phase and a gas phase to convert an aromatic hydrocarbon in a hydrocarbon feed to a hydrogenation product by contacting the aromatic hydrocarbon with hydrogen in a hydrogen feed in the presence of a hydrogenation catalyst;
• a pump-around loop comprising a pump configured to move a withdrawn portion of the liquid phase from the hydrogenation reactor through the pump-around loop and back to the hydrogenation reactor;
• at least one primary heat exchanger after the pump in the pump-around loop wherein the primary heat exchanger is configured to reduce the temperature of at least a portion of the liquid phase withdrawn from the hydrogenation reactor, thus providing a reduced-temperature withdrawn portion, prior to introduction of the reduced-temperature withdrawn portion into the hydrogenation reactor;
• and
• (a) at least one additional heat exchanger in parallel with the at least one primary heat exchanger, wherein the additional heat exchanger is configured such that the at least one primary heat exchanger can be placed offline while the at least one additional heat exchanger is placed online;
• and
• (b) a separator upstream of the at least one primary heat exchanger, wherein the separator is configured to separate a decomposition product of the hydrogenation catalyst, the hydrogenation catalyst, or both from the withdrawn portion of the liquid phase;
• and
• (c) a source of a component that will react with an oxygen-containing species in the hydrocarbon feed, the hydrogen feed, or both.