The Distinctive Feature is process conduction at lower pressure which makes it possible to exclude the use of expensive compressors.
AMS Hydrogenation is based on a catalytic alpha-methyl styrene conversion to cumene. The process is operated at a lower hydrogen partial pressure (below 5 kg/cm2 abs.), unlike usual hydrogenation at phenol plants, which occurs at 30 kg/cm2 abs. partial pressure. Use of this process option saves capital investment in the unit construction due to employment of circulation gas blower instead of expensive high-pressure compressors and due to lower equipment design pressure. The process achieves a high degree of AMS conversion to cumene, which is then recycled back to the Cumene Oxidation Stage. The high degree of AMS to cumene conversion prevents carryover of large amount of an inhibitor such as AMS to the Cumene Oxidation Stage.