The XyMax technology developed by ExxonMobil Chemical offers xylenes isomerization using a unique ZSM-5 based catalyst system to produce paraxylene and orthoxylene from C8 aromatics feedstocks. It provides higher yields and reduces recycle rates compared to competing technologies. The process achieves over 100% paraxylene selectivity and offers advantages like higher ethylbenzene conversion, lower xylene losses, and lower operating costs.

1. THE LEADING EDGE IN XYLENES’
ISOMERIZATION
Through an exclusive agreement with ExxonMobil
Chemical Company, Axens offers the XyMaxSM
xylenes isomerization technology developed by
ExxonMobil Chemical to produce paraxylene and
orthoxylene with high selectivity from C8 aromatics
feedstocks. XyMax ideally fits into your grassroots
xylenes isomerization plants. The unique ZSM-5
based catalyst technology gives high product yields,
reduces C8 aromatics recycle due to higher
ethylbenzene conversion and provides more flexibility
than competing technologies.
OUTPERFORMS THE COMPETITION
The XyMax process offers advantages over the
competition, such as:
• Higher ethylbenzene conversion
• Lower xylene losses even at high EB conversion
• Greater than 100% paraxylene approach to
equilibrium
• High non aromatics conversion
• Lower operating costs
• Smaller catalyst volumes
• Long operating cycles and ultimate catalyst life
ADVANCED ZSM-5 TECHNOLOGY
XyMax incorporates the latest advances in
ExxonMobil Chemical's ZSM-5 catalyst technology.
Using a unique dual bed catalyst system and low
hydrogen circulation, the process optimizes EB
conversion, non aromatics cracking and the
isomerization of meta- and orthoxylene to paraxylene.
PROCESS DESCRIPTION
In the XyMax process (see overleaf), feed is a mixture
of fresh and recycled C8 aromatics in which
paraxylene (and orthoxylene, if desired) is depleted to
less than equilibrium concentrations. The mixed
xylene and ethylbenzene feed combined with
hydrogen-rich recycle gas is preheated and passed
through the reactor where ethylbenzene dealkylation
and xylenes isomerization occur to produce a
paraxylene containing effluent in excess of the
thermodynamic equilibrium. The reactor effluent is
cooled by heat exchange and the liquid products are
separated from the recycle gas, stripped to remove
light ends and fractionated to remove benzene and
toluene.
The bottoms from the fractionation section are then
recycled to the paraxylene or orthoxylene recovery
section; here shown as a xylenes splitter and the
Eluxyl®
process.
OVER 25 YEARS OF COMMERCIAL
EXPERIENCE
ExxonMobil Chemical has experience in the field of
xylene isomerization since 1973 and more than one
third of the world's xylene isomerization capacity uses
this technology.
XyMax has today seventeen industrial references
worldwide. All units are demonstrating excellent
performance.
XyMax technology operates at ethylbenzene
conversion levels of 70-80+%, reflecting the inherent
stability of the catalyst. Moreover, long first cycles
can be achieved, typically four years or more. One
unit using MHAI catalyst in the XyMax process
operated for ten years on its first cycle before
upgrading to Advanced MHAI.
XyMax
SM
EXXONMOBIL CHEMICAL XYLENES ISOMERIZATION

2. EM-4500 THE NEWEST XYLENE
ISOMERIZATION CATALYST
Commercialized in 2000, EM-4500 is ExxonMobil
Chemical's newest xylenes isomerization catalyst
incorporating the latest advances in ZSM-5 catalysts.
EM-4500 features a drastically reduced level of
losses, which will further improve the Xylenes Loop
efficiency. This high level of performance is obtained
under even more cost effective operating conditions as
compared to previous generation catalysts such as
Conventional or Advanced MHAI
XYMAX: A KEY COMPONENT IN PARAMAX
XyMax is ideally suited to play a key role in the
ParamaX™ technology suite, especially when
maximum paraxylene production with benzene co-
production is desired.
The XyMax isomerization process will result in a
lower investment and operating cost choice for any
ParamaX®
process suite.
XyMax is a trademark of ExxonMobil.
ParamaX and Eluxyl are proprietary process names of Axens.
Jan.11-XyMax
Eluxyl
Hydrogen
C8
Aromatics
Feed
Off Gas
Benzene
And
Toluene
Paraxylene
C9
Aromatics
cw
cw
XyMax Process Limits
Simplified XyMax flowscheme