Alkyfining – Selective butadiene/MAPD hydrogenation
Alkyfining® is the market leader for upgrading unsaturated LPG cuts; by converting butadiene and MAPD it greatly enhances the performance of downstream units.
Butadienes and MAPD are highly reactive and have the tendency to form oligomers when treated in downstream catalytic units. In the case of fixed-bed technology units (e.g. Axens Polynaphtha technology), these oligomers block the catalyst pores leading to premature deactivation and an increase in pressure drop. In the case of homogenous catalytic units (e.g. H2SO4 Alkylation, Axens Dimersol-G etc.), these oligomers need to be purged leading to catalyst loss or increased cost for acid regeneration.
Alkyfining solves these problems and delivers remarkable results; it is distinguished by:
The treatment of the olefin cut in the liquid state, reducing the operating cost to a minimum.
The use of a family of palladium catalysts on a special alumina carrier. These catalysts are continually being improved in order to meet specific client objectives.
Optimized reactor design to ensure good fluid distribution maximizes olefin yield and the catalyst cycle.
Accurate distribution is of paramount importance to selectively hydrogenate dienes without saturating olefins. Axens’ proprietary internal (Hy-UpTM distributor tray) now proposed in the Alkyfining technology makes it possible to take maximum advantage of the high intrinsic activity and selectivity of Axens catalysts. In addition to providing high turndown capabilities (40% of normal flow), this design eradicates the potential for channeling and hot spots which result in lower olefin yield and a shorter catalyst life.
Particular attention is given to the presence of contaminants in cracked feedstock from FCC and coker units. Axens catalysts have particularly high resistance to sulfur, and if catalyst activity is reduced by temporary poisons, it is restored quickly using simple procedures. Full catalyst regeneration can be carried out in situ or off site. Cycles of over three years and service lives in excess of six years are typical.