High octane C₅/C₆ cuts via isomerization

processes

OIL C5/C6 isomerization is a must-have for

REFINING
refiners who want to maximize the profi-
Axens’ ATIS-2L chlorinated
tability of their gasoline pool. This process
alumina catalyst leads the
can be adapted to various configurations
pack
and allows improving C5/C6 naphtha cut
octane numbers up to 92 without constraints Chlorinated alumina is a catalyst
on olefins and sulfur. of choice thanks to its high activity
permitting operation at lower reactor
Axens is licensing a complete set of
temperatures that enable higher product
isomerization configurations in order to
RON and favor superior yields (figure 1).
| Isomerization

support refiners to resolve the evolving

The use of molecular sieve adsorbents on
gasoline pool equation.
the feed and hydrogen make-up streams
ensures the removal of feed contaminants
COMMERCIAL and long catalyst lifetimes.
EXPERIENCE
Axens isomerization technologies use
With a powerful R&D support at both lab ATIS-2L catalyst which provides an
and pilot scales, Axens has achieved a unsurpassed combination of high activity,
significant market penetration through low cost and low platinum content.
the implementation of innovative
process schemes combined with state-
of-the-art chlorinated alumina catalysts.

More than 85 isomerization units have

been licensed by Axens, and since the
marketing of ATIS-2L catalyst in 2003,
more than 60 new units have been designed.

ÏÏFigure 1: Different catalyst type performances

{ CASE STUDY }

Based on more than 10 years of

industrial experience, ATIS-2L has
demonstrated a high degree of
reliability, stability, and flexibility versus
the feedstocks processed in the
isomerization units.

ÏÏFigure 2: ATIS-2L response to feed severity

variation over 10 years operation (Reactors
effluent - Once-Through Scheme)
 ››Once-through C /C 5 6
isomerization to achieve octane improvement by either
This least-cost path to moderate octane allowing isomers to bypass the reactors
Axens’ commitment to gain can provide, in some cases, a sufficient (DIP) or by recycling normal paraffins to
research & development boost to the gasoline pool octane. Typically, the reactors (DIH, or combination of
Although isomerization is a mature the octane for a feed having a C5 to C6 ratio DIP, DP and DIH)(figure 3). However, these
technology, Axens continues to invest in of 40:60 will have an increase in RON from approaches still leave normal paraffins in
R&D to improve the designs and catalysts 70 to 83-84 after isomerization. the product.
and aim at lower investment, operating
costs and emissions.
The scheme (figure 4) is based on a ››Advanced recycle:
permutable reactors design; that is, either IPSORB™ / HEXORB™
One recent innovation is a plug & play reactor can be used in the lead or lag position Ipsorb™ and Hexorb™ processes are
system that allows to drastically reduce or it can be operated independently during an alternate path available to convert
chemicals consumption combined with catalyst servicing. This insures a ultra-high all normal paraffins to their iso-paraffins.
octane-barrel improvement. on-stream service. A vapor phase molecular sieve section
is used to adsorb normal paraffins
Dried Scrubber Off Gas (figure 3) for recycling to the reactors.
Tailor made technology Hydrogen

selection R-1 R-2

Stab

Axens isomerization technologies are ready
Dried Light
Naphtha Isomerate B E N E F I T S
to meet refineries' octane objectives. Relative
differences between the isomerization ÏÏFigure 4: Once-through isomerization with •• Chlorinated alumina catalyst is
schemes with regard to investment cost, permutable reactors today’s catalyst choice
operating cost and product revenue, are
shown in the figure 3 (based on ATIS-2L
››Octane enhancement with •• Axens’ ATIS-2L leads the pack
catalyst). Axens isomerization technologies
deisopentanizer (DIP) or/and •• Highest isomerization yields
deisohexanizer (DIH) or/and •• Continuous innovation in technology
are also well suited for stepwise installation
depentanizer (DP)
of octane improvement projects.
The maximum octane number available
•• Best answer for maximizing the
octane-barrel performance
from a once-through system is limited by
the thermodynamic equilibrium of the C5/ •• Tailor made technology selection
C6 mixture (figure 4). Distillation is one way
Operating cost and product revenue
RON
+ 110 % 92

+ 90 % 90

+ 70 % 88

+ 50 % 86

+ 30 % 84

+ 10 % 82
BASE
80
Dried Scrubber Off Gas
Hydrogen
R-1 R-2
Stab

Dried Light
Naphtha Isomerate

Once Through DIP + Isomerization DIP + Ipsorb™ DIP + Isomerization + Hexorb™

Once Through with DIH Isomerization with DIH DP + DIH

ÏÏFigure 3: Economics for each isomerization processing scheme using GRAPH SCHEMES
ATIS-2L chlorinated alumina catalyst  ISBL Investment Cost I RON  Once Through
 Operating Cost  Molecular Sieves
 Product revenue

Axens is a group providing a complete range of solutions for the conversion

of oil and biomass to cleaner fuels, the production and purification of major
petrochemical intermediates as well as all of natural gas treatment and conversion
options. The integrated offer includes technologies, equipment, furnaces, modular
axens.net/blog units, catalysts, adsorbents and related services, commercialized under “Axens
Solutions”, “Heurtey Petrochem Solutions” and “Axens Horizon” brands.

2017-09_Isomerization