Catalagram 107 - Grace

In this issue
• GENESIS ® Catalyst Commercial Update
Issue No. 107 / 2010 / www.grace.com
Catalagram®
A Refining Technologies Publication
• Distillate Pool Maximization by Additional Hydroprocessing
• Salt Deposition in FCC Gas Concentration Units
• CP ® P - Third Generation Low NOx CO Promoter

The road to FCC profitability just got straighter:
Grace Davison introduces Astera
Grace Davison Refining Technologies
www.grace.com
Improve your FCCU’s profitability with Grace Davison’s new Astera FCC catalyst. Astera is built upon a novel
unconventional silica-alumina binding system that delivers better unit retention and catalyst fluidization. The com-
bination of the intrinsic bottoms cracking from the unique binder with smoother catalyst circulation makes Astera
a natural for bottoms cracking. Best of all, Astera will lower your daily catalyst cost.
Developed by our world-class R&D group, Astera was specially designed to meet the profitability challenges of
today’s refiners.
We don’t just make FCC catalysts, we make FCC catalysts for you. www.e-catalysts.com
W. R. Grace & Co. - Conn.
7500 Grace Drive
Columbia, MD 21044 USA
+1 410.531.4000
Grace GmbH & Co. KG
In der Hollerhecke 1
67545 Worms, Germany
+49 624.140.300
W. R. Grace Singapore PTE Ltd.
501 Orchard Road
#07-02 Wheelock Place
Singapore 238880
+65 6737.5488
Grace ® and Grace Davison ® are trademarks, in the United States and/or other countries, of W. R. Grace & Co.-Conn. The information presented herein is derived from our testing and experience. It is offered, free of charge, for your
consideration, investigation and verification. Since operating conditions vary significantly, and since they are not under our control, we disclaim any and all warranties on the results which might be obtained from the use of our products.
You should make no assumption that all safety or environmental protection measures are indicated or that other measures may not be required. © 2010 W. R. Grace & Co.-Conn.

A MESSAGE FROM THE EDITOR...
Managing Editor Joanne Deady and Technical
Editor Rosann Schiller
Dear Refiners,
The current refining atmosphere in North American and
Europe is the most difficult in over a quarter century.
Declining utilization rates, narrow light-heavy differentials,
and weak demand for transportation fuels has meant
steeply declining profitability for refiners.
As the leading supplier of FCC catalysts and additives,
Grace Davison is dedicated to helping you navigate this
turbulence. Our investment in world-class research and
development to constantly invent new products and finetune
existing ones continues strong in this challenging
environment. With our flexible technology base and broad
manufacturing capabilities, we deliver the catalyst solutions
you need to be profitable and the value you deserve.
This issue of the Catalagram ® highlights the successful application flexibility of our GENESIS ® solutions to our
customers' challenge of the need to react quickly to changing supply/demand dynamics. These catalysts have
been custom blended in 80 applications for over 50 refineries worldwide. As product slate demand changes,
GENESIS ® catalyst in the unit can be reformulated to maximize profitability and capture short term economic
opportunities. To speed implementation, formulation adjustment can take place in the fresh hopper, minimizing
the delay often associated with a catalyst change out.
We also introduce our third generation non-platinum low NOx CO promoter, CP ® P. Our newest CO promoter
delivers quick CO/afterburn response, equivalent to traditional platinum formulated promoters, and up to 20%
lower NOx emissions compared to competitive products.
On the immediate horizon, we introduce our new products Astera TM and Alcyon TM . Units that are circulation limited
can’t take full advantage of improved feed quality. When the FCC catalyst is not active enough regenerator
temperatures become too low and desired reactor temperatures can’t be achieved. Some refiners resort to
burning torch oil or recycling slurry to provide additional delta coke which is often detrimental to the operation.
With its novel, unconventional silica-alumina binder, Astera TM FCC catalyst not only delivers excellent value but
will improve your yield slate and reliability. Best of all, Astera TM will lower your daily catalyst cost. Alycon TM is a
revolutionary new FCC catalyst designed for the maximum activity needed to process hydrotreated feeds. Look
for more information from us in the coming months.
Our responsibility to our refining customers is the core of our business. We pledge to continue developing the
products and services that will maximize your profitability in all economic climates.
Joanne Deady
Vice President, Global Marketing
Grace Davison Refining Technologies
GRACE DAVISON CATALAGRAM 1

IN THIS ISSUE
04 Grace Davison’s GENESIS ® Catalyst Systems
Provide Refiners the Flexibility to Capture
Economic Opportunities
By Rosann K. Schiller
GENESIS ® is one of Grace Davison’s most successful catalysts,
with 20% of the world’s FCC capacity, having utilized the technology.
GENESIS ® systems offer refiners formulation flexibility and the ability
to realize the desired yield shifts quickly in order to capture dynamic
economic opportunities.
13 Development of Next Generation Low NOx
Combustion Promoters Based on New
Mechanistic Insights
By Eric Griesinger, Mike Ziebarth and Uday Singh
Grace research and development efforts have led to the development
of CP ® P, a new low NOx combustion promoter. Data from
multiple field trials has indicated excellent CO control with quick
response to afterburn and/or CO excursions, like traditional Ptbased
promoters. However, unlike traditional promoters, CP ® P provides
lower NOx emissions and very quick NOx emission decay
periods.
22 Distillate Pool Maximization
by Additional LCO Hydroprocessing
By Brian Watkins, David Krenzke and Charles Olsen
Advanced Refining Technologies ® has developed catalysts specifically
designed to handle more difficult feeds exemplified by the
SmART Catalyst System ® technology for ULSD. This technology
has been widely accepted, with over 75 units in commercial service
since its inception. ART continues to improve its line of ultra high
activity ULSD catalysts with the addition of an SRO catalyst.
34 Salt Deposition in FCC Gas Concentration
Units
By Michel Melin, Gordon McElhiney and Colin Baillie
Various operational problems can arise when salt deposition occurs
in FCC gas concentration units. Grace Davison Technical Service
troubleshoots users of alumina sol catalysts to manage and solve
any issues of ammonium chloride deposition.
Catalagram 107
ISSUE No. 107 / 2010
Managing Editor:
Joanne Deady
Technical Editor:
Rosann Schiller
Contributors:
Colin Baillie
Eric Griesinger
David Krenzke
Gordon McElhiney
Michel Melin
Charles Olsen
Rosann Schiller
Uday Singh
Brian Watkins
Mike Ziebarth
Please address your comments to:
betsy.mettee@grace.com
Grace Davison Refining
Technologies
Advanced Refining Technologies
7500 Grace Drive
Columbia, MD 21044
410.531.4000
www.e-catalysts.com
www.grace.com
www.artcatalysts.com
© 2010
W. R. Grace & Co.-Conn.
Issue No. 107 / 2010 / www.grace.com
®
Catalagram
A Refining Technologies Publication
In this issue
• GENESIS ® Catalyst Commercial Update
• Distillate Pool Maximization by Additional Hydroprocessing
• Salt Deposition in FCC Gas Concentration Units
• CP ® P - Third Generation Low NOx CO Promoter

Grace Davison’s GENESIS ® Catalyst
Systems Provide Refiners the Flexibility
to Capture Economic Opportunities
Rosann K. Schiller
Product Manager
FCC Catalyst
Grace Davison
Refining Technologies
Columbia, MD USA
4 ISSUE No. 107 / 2010
In these challenging times, refiners
more than ever need flexibility.
Demand for gasoline and
diesel is down due to the recession.
Product supply is volatile
as refineries slow down rates
and inventories rise with weak
consumption; other refiners are
extending turnarounds or in
extreme cases, shutting down.
Historically, the relative value of
diesel to gasoline would fluctuate
with the seasons in a fairly
consistent band. However, as
ultra-low sulfur fuels become
standard, the price differential
between diesel fuel and gasoline
has become extremely volatile
[Figure 1]. The refiners that are
most successful are those that
can react quickly to the changing
supply/demand dynamics.

Grace Davison delivers the flexibility
most refiners need with the
GENESIS ® catalyst system.
GENESIS ® catalysts provide a
means to maximize yield potential
through the optimization of
discrete cracking catalyst functionality
1.
The GENESIS ® catalyst system
has gained rapid market acceptance
since it was launched by
Grace Davison [Figure 2]. GEN-
ESIS ® catalyst systems offer
refiners formulation flexibility and
the ability to realize the desired
yield shifts quickly in order to
capture dynamic economic
opportunities. GENESIS ® catalyst
is one of Grace Davison’s
most successful catalysts, with
20% of the world’s FCC capacity
having utilized the technology
[Figure 3].
It is well known that the key to
optimal FCC catalyst performance
is the right balance
between zeolite and matrix both
in selectivity and activity. One
representation of this is Z/M surface
area ratio. 2 GENESIS ® catalysts
are a blend of two catalyst
types in which the principal component
is a MIDAS ® catalyst.
This concept provides the option
to optimize formulation Z/M for
each individual application. In
many catalyst development
tests, the expectation of performance
for catalyst blends is
that the resultant yields can be
estimated by the linear average
of the yields from each individual
catalyst. In performance testing
of GENESIS ® catalyst systems,
the resultant yields exceed those
of the individual components
[Figure 4]. A synergistic effect
therefore exists such that GEN-
ESIS ® catalysts demonstrate a
superior coke to bottoms relationship
than either component
alone. Remarkably, this effect is
Figure 1
US Historical Price Differential Between Diesel
and Gasoline
Diesel - Gasoline Differential, cpg
Number of Refiners
100
80
60
40
20
0
-20
-40
Source: Energy Information Administration
-60
Jan 94 Jan 98 Jan 02 Jan 06 Jan 10
Figure 2
GENESIS ® Catalyst Has Gained
Market Acceptance Quickly
60
50
40
30
20
10
0
Figure 3
Worldwide Application
2006 2007 2008 2009
Worldwide FCC Capacity, BPD
GENESIS ®
Catalyst
All Other
Catalysts
Source: Oil & Gas Journal
GRACE DAVISON CATALAGRAM 5

Figure 4
Evidence of GENESIS ® Catalyst Synergy
in Performance Testing
Conversion, wt.%
80.0
76.0
72.0
68.0
64.0
1.5
6 ISSUE No. 107 / 2010
2.0 2.5 3.0 3.5
Coke, wt.%
GENESIS ® Catalyst
IMPACT ® Catalyst
MIDAS ® Catalyst
Theoretical Blend
observed across a broad range
of feeds: resid, VGO and
hydrotreated feedstocks 1.
For new applications, Grace’s
experienced technical service
engineers carefully formulate the
GENESIS ® catalyst to achieve
the stated goals of the refiner.
Often, several scenarios (e.g.
max gasoline or max LCO) are
prepared and presented to illustrate
the flexibility and the power
of GENESIS ® catalyst to change
product slate. As product supply/demand
balance shifts, GEN-
ESIS ® catalyst in the unit can be
reformulated to maximize profitability
and capture short term
economic opportunities. To
speed implementation, formulation
adjustment often takes
place in the fresh hopper, minimizing
the delay often associated
with a catalyst change out.
Grace has had over 80 applications
of GENESIS ® catalysts in
over 50 refineries [Table I] worldwide
where the average user
has reformulated, sometimes
more than once to achieve new
objectives. Examples of these
successful commercial applications
are presented here. In
each case, GENESIS ® catalyst
was either introduced or the
blend reformulated to achieve
the new objectives.

Current Worldwide Use
Refiner 1
The synergy we observe in laboratory
testing has easily translated
to field operation. Figure 5
illustrates the performance
advantage observed in commercial
testing with GENESIS ® catalyst.
The data presented here
are three commercially deactivated
Ecats taken from an FCC
unit processing resid that has
used IMPACT ® and MIDAS ® catalysts
separately as well as in a
GENESIS ® catalyst system.
These Ecats were then tested in
an ACE pilot plant over a single
feed from the same unit. GENE-
SIS ® catalyst has the advantage
in coke-selective bottoms cracking.
Refiner 2
A refiner processing hydrotreated
feed switched from a state-ofthe-art
Grace Davison catalyst
for hydrotreated feeds to a GEN-
ESIS ® system. Figure 6 demonstrates
the performance
advantages of GENESIS ® catalyst
relative to the hydrotreating
benchmark technology. In ACE
testing of unit Ecats, GENESIS ®
catalyst results in an improved
coke-to-bottoms relationship,
ultimately providing operating
flexibility for this refiner to optimize
hydrotreating and FCC
operations.
This same refiner has also reformulated
their GENESIS ® catalyst
to take advantage of shifting
economics between gasoline
and LCO, by increasing the
MIDAS ® catalyst portion of the
blend. To accelerate turnover to
the new formulation, Grace
shipped MIDAS ® catalyst to
adjust the formulation in the
fresh hopper, eliminating any
delay associated with excess
fresh catalyst inventory. The
Table I
GENESIS ® Catalyst Users
Unit Region Feed Type Ni + V, ppm
Refiner 1
Refiner 2
Refiner 3
Refiner 4
Refiner 5
Refiner 6
Refiner 7
Refiner 8
Refiner 9
Refiner 10
Refiner 11
Refiner 12
Refiner 13
Refiner 14
Refiner 15
Refiner 16
Refiner 17
Refiner 18
Refiner 19
Refiner 20
Refiner 21
Refiner 22
Refiner 23
Refiner 24
Refiner 25
Refiner 26
Refiner 27
Refiner 28
Refiner 29
Refiner 30
Refiner 31
Refiner 32
Refiner 33
Refiner 34
Refiner 35
Refiner 36
Refiner 37
Refiner 38
Refiner 39
Refiner 40
Refiner 41
Refiner 42
Refiner 43
Refiner 44
Refiner 45
Refiner 46
Refiner 47
Refiner 48
Refiner 49
Refiner 50
Refiner 51
Refiner 52
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
NA
LA
NA
NA
NA
LA
NA
NA
NA
NA
NA
NA
AP
NA
LA
NA
NA
NA
NA
NA
NA
AP
NA
LA
NA
AP
NA
NA
NA
AP
LA
AP
NA
NA
NA
AP
LA
LA
NA
LA
AP
AP
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
Hydrotreated
VGO
VGO
VGO
VGO
VGO
VGO
VGO
VGO
VGO
VGO
VGO
Resid
VGO
Resid
Resid
VGO
Resid
Resid
Resid
Resid
Resid
Resid
VGO
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
Resid
350
450
600
700
800
800
850
900
1000
1100
1100
1200
1400
1400
1500
1500
1700
2000
2000
2000
2200
2200
2500
2700
2800
2800
3000
3000
3000
3500
4300
4500
5000
5000
5000
5500
6000
6500
6500
6500
7000
7000
7000
7000
7000
8500
9000
9000
9500
10000
11500
16000
GRACE DAVISON CATALAGRAM 7

Figure 5
Evidence of GENESIS ® Catalyst Synergy is Observed Commercially
10
5
0
-5
-10
-15
-20
Bottoms, wt.%
Figure 6
Commercial Data from Refiner 2
Delta
Rg T, ˚F
Delta
Rx T, ˚F
new GENESIS ® catalyst formulation,
when combined with adjusted
operating conditions –
reduced ROT and endpoint
adjustments – enabled the refiner
to maximize LCO production
up to their downstream handling
limits, without sacrificing octane
or volume expansion. Total yield
benefit was $0.50/bbl.
8 ISSUE No. 107 / 2010
9
8
7
6
5
4
4.5 5.0 5.5 6.0 6.5 7.0 7.5
Observed Commercial Operations and Yields Shifts - GENESIS ® Catalyst
C/O
Shift % Rel
Delta Coke
Shift % Rel
Coke, wt.%
2.5
2.0
1.5
1.0
0.5
0.0
-0.5
-1.0
G+D,
vol.%
Refiner 3
Another refiner changed from a
competitive catalyst to a GENE-
SIS ® catalyst. The yield benefits
are summarized in Table II.
GENESIS ® catalyst delivered
enhanced bottoms conversion,
gasoline and coke selectivity. In
addition, GENESIS ® possesses
more favorable fluidization char-
IMPACT ® Catalyst
MIDAS ® Catalyst
GENESIS ® Catalyst
Slurry,
vol.%
LPG,
vol.%
Dry Gas,
wt.%
acteristics than the competitive
sample, and helped to overcome
circulation instability [Figure 7].
GENESIS ® catalyst has also provided
the flexibility to maximize
profitability based on current
supply/demand economics.
Since introduction to the unit,
Refiner 3 has reformulated GEN-

ESIS ® catalyst twice; first to
maximize LCO and again to
return to a gasoline operation.
In the max LCO operation, the
percentage of MIDAS ® catalyst
was increased in the blend to
maximize bottoms cracking and
reduce Z/M. The shifts achieved
in the max LCO case are summarized
in Table II. GENESIS ® 2
catalyst, formulated for max
LCO, delivered an additional 3.5
lv.% yield for a net increase of 5
lv.% LCO and 2.2 lv.% reduction
in slurry relative to the competitive
base catalyst. When economics
became favorable for
gasoline, the refiner returned to
the original formulation. Overall,
these yield shifts were worth
between $0.45 and $1.00/bbl,
depending on the operating
mode and the refining margins
at the time.
For both catalyst reformulations,
the blend ratio of MIDAS ® catalyst
and IMPACT ® catalyst was
adjusted to achieve the desired
yield shift. Grace was able to
reduce turnover time by working
with the refiner to readjust the
formulation within the fresh catalyst
hopper.
Refiner 4
A major refiner desired additional
bottoms conversion. A switch to
GENESIS ® catalyst delivered
increased conversion to gasoline
and LPG without sacrificing coke
selectivity. The yield shifts are
shown in Table III. The new
GENESIS ® catalyst achieved the
goal of 2% more conversion at
equivalent coke yields, increasing
revenue by $0.44/bbl.
Refiner 5
A refiner desired increased bottoms
conversion and enhanced
LCO production. The use of a
GENESIS ® catalyst, along with
an adjustment in operating con-
Table II
GENESIS ® Catalyst Provided Refiner 3 the Flexibility
to Shift Between Gasoline and LCO Modes
Gasoline, lv.%
LCO, lv.%
Bottoms, lv.%
Fluidization Factor (Umb/Umf)
3.8
3.6
3.4
3.2
3.0
2.8
Competitive
Catalyst
Base
Base
Base
GENESIS ® Catalyst
Competitive Catalyst
GENESIS ® 1
(Max Gasoline)
relative to base
+3.0
+1.5
-1.5
Figure 7
Fluidization Improved with GENESIS ® Catalyst
at Refiner 3
Oct Jan Apr Jul Oct
Table III
GENESIS ® Catalyst Yield Shifts at Refiner 4
Feed ˚API
Regenerator Temperature, ˚F
Light Ends, lv.%
Gasoline, lv.%
LCO, lv.%
Slurry, lv.%
Conversion, lv.%
Yield shifts
with
GENESIS ®
-1.0
-7.0
0.5
1.5
-
-2.0
2.0
GENESIS ® 2
(Max LCO)
relative to base
+1.0
+5.0
-2.2
GRACE DAVISON CATALAGRAM 9

ditions, delivered a 5% increase
in LCO without a debit in coke
selectivity. When economics
returned to favor gasoline, similarly
to the earlier example, the
blend ratio was adjusted and
severity increased to favor a
gasoline operation. The new
GENESIS ® catalyst formulation
delivered operating flexibility and
enhanced profitability by
$0.55/bbl.
Refiner 6
A refiner processing resid was
seeking additional bottoms
cracking without sacrificing coke
selectivity or metals tolerance.
GENESIS ® catalyst delivered an
increase of +10 m 2/g in Ecat
matrix surface area, a 1.5 lv.%
reduction in bottoms yield, and
+2.0 lv.% conversion compared
Figure 8
Ecat Selectivities are Maintained with GENESIS ® Catalyst
Despite Higher Ecat Metals
2.50
2.25
2.00
1.75
1.50
8
6
4
2
4500
10 ISSUE No. 107 / 2010
Coke Factor
Gas Factor
to a base IMPACT ® catalyst formulation.
Even though Ecat
metals levels increased by
almost 10% due to a feed
change, GENESIS ® maintained
coke, H 2, and gas selectivity.
[Figure 8]
Refiner 7
This refiner adopted GENESIS ®
catalyst to replace a competitive
resid technology. GENESIS ®
delivered 1.5 lv.% increase in
conversion to gasoline and LPG
olefins, at the expense of slurry,
4750 5000 5250 5500
200
175
150
125
100
Ecat Ni Equivalents, ppm
which was worth $0.43/bbl. Not
only has GENESIS ® catalyst
minimized slurry yield, it did so
without the expected coke and
gas penalty often observed with
competitive high matrix catalysts.
GENESIS ® catalyst
“GENESIS ® catalyst systems have been
applied in over 50 refiners worldwide with
80 discrete applications.”
allowed this refiner to maximize
feed carbon content up to the
coke burn limit.
Refiner 8
The success of GENESIS ® catalyst
has spurred some competi-
H 2 Yield SCFB
4500 4750 5000 5250 5500
IMPACT ® Catalyst
GENESIS ® Catalyst

tive imitations. One refiner has
trialed both a competitive offering
as well as a GENESIS ® catalyst
system. The yields are
summarized in Table IV. At
equivalent activity and coke
yield, GENESIS ® catalyst delivered
enhanced bottoms cracking.
Hydrogen selectivity was
also improved at equivalent Ecat
metals. Emulating the performance
of GENESIS ® catalyst is
not as simple as merely blending
a high zeolite activity catalyst
with a high matrix catalyst. The
combination of MIDAS ® catalyst
matrix technology with Grace’s
proprietary zeolite technology
results in a true synergy
unmatched by the competition.
Refiner 9
Lastly, we hear a lot about how
additives are the easy way to
achieve a desired yield shift
quickly. Additives can generally
be delivered and injected into
the inventory quickly, – provided
the appropriate injection equipment
is in place, the loader
lease agreement allows use of
an additive, the additive is available
in inventory, and management
approves the use of the
product. For a very short term
opportunity, once the hurdles are
overcome, an additive usually
works well.
However, additives are not custom
formulated products.
Therefore, if a refiner is looking
for a long term application, and
the additive is not delivering, the
desired yield shifts will not be
achieved. A refiner desired additional
bottoms cracking and trialed
both an additive solution
and a GENESIS ® catalyst system.
The additive solution did
provide incremental bottoms
cracking, but because it was not
designed and formulated for this
Table IV
GENESIS ® Catalyst Provided Refiner 8
Performance Advantages Relative to the Competition
Constant Coke
Comparison Catalyst
Conversion, wt.%
H2/CH4 Ratio
Gasoline, wt.%
LCO/Bottoms, w/w
Total Ecat Metals, ppm
H2/CH4 Ratio
Gasoline, wt.%
LCO, wt.%
Bottoms, wt.%
Coke, wt.%
GENESIS ®
71.8
0.6
48.4
3.0
2353
Additive approach
relative to base
0.1
-0.9
0.3
-0.4
0.8
Competitive
Catalyst
66.8
0.8
45.7
2.6
2139
Table V
GENESIS ® Catalyst Delivered Refiner 9 More
Selective Bottoms Cracking than an Additive Approach
operation, the consequence was
a substantial coke debit and a
loss in gasoline yield. The GEN-
ESIS ® catalyst formulation, with
each component designed and
manufactured specifically for the
application, delivered the targeted
bottoms conversion, while
improving coke and gas selectivities
relative to the base operation
[Table V].
GENESIS ®
Catalyst
relative to base
-0.1
--
1.3
-1.4
-0.1
GRACE DAVISON CATALAGRAM 11

Conclusions
GENESIS ® catalyst offers customers
the ultimate in formulation
flexibility and the option to
realize those changes quickly. A
decision to reformulate within a
GENESIS ® catalyst system typically
happens 80% quicker than
with a traditional catalyst
because simply changing the
blend ratio presents a lower risk
option than a new catalyst or
even a new additive.
GENESIS ® catalyst systems
have been applied in over 50
refiners worldwide with 80 discrete
applications. Catalyst Z/M
12 ISSUE No. 107 / 2010
ratio can be optimized to match
the specific unit feedstock and
operating constraints. In addition
to optimizing the blend ratio,
the activity levels of the individual
components are carefully
selected to match the operating
mode and feed types. This formulation
flexibility can deliver a
significant selectivity change,
allowing a refiner to accommodate
a seasonal operation, manage
a swing feedstock or even a
hydrotreater outage, and most
importantly, GENESIS ® catalyst
systems allow refiners to capture
short term economic opportunities.
References
1. Schiller, R., et al, “The GENESIS
Catalyst System,” Catalagram ® publication
No. 102, Fall 2007.
2. Mott, R.W., Wear, C. “FCC Catalyst
Design for Optimal Performance,” NPRA
1988, AM-88-73.

Development of Next Generation
Low NOx Combustion Promoters
Based on New Mechanistic Insights
Eric Griesinger
Product Manager
Environmental Additives
Grace Davison
Refining Technologies
Columbia, MD
The use of low NOx combustion
promoters in FCC units has
increased in recent years due to
stricter NOx emission limits and
implementation of EPA consent
decrees. Further, the recent EPA
issued final amendments to its
New Source Performance
Standards for Petroleum
Refineries indicate that additives
are now included as Best
Demonstrated Technology in the
Mike Ziebarth
Manager
Synthesis Research
Grace Davison
Refining Technologies
Columbia, MD
reduction of FCCU NOx emissions.
Studies to determine
mechanisms by which low NOx
promoters reduce NOx, as well
as determining the FCCU operating
parameters that effect NOx
formation are the focus of this
paper. A lab scale regenerator
test unit was used to study the
combustion of coked ecat at conditions
that closely simulate the
regenerator of an FCCU. This
Udayshankar G. Singh
Research & Development
Engineer
Grace Davison
Refining Technologies
Columbia, MD
unit was used to explore the
impact of certain regenerator
variables, including excess O 2
level and type of combustion promoter
on CO and NOx emissions.
In addition, fixed bed
reactor experiments were carried
out to study the oxidation of
reduced nitrogen species on platinum
(Pt) and non-Pt based combustion
promoters to help
elucidate mechanistic differences.
GRACE DAVISON CATALAGRAM 13

Based on this improved mechanistic
understanding of how low
NOx combustion promoters work,
a new combustion promoter has
been developed. Commercial
field trials show excellent results.
Background
FCC units account for about
10% of the nitrogen oxide emissions
generated by stationary
sources in the United States.
These NOx emissions are the
result of nitrogen impurities in
the feed depositing on the catalyst
during the cracking reaction.
When the coke is burned off in
the regenerator, a portion of the
nitrogen is converted into NOx.
Since NOx emissions are a contributor
to acid rain, precursors in
the formation of ground level
ozone, and contribute to respiratory
health impacts, the EPA and
various state and local agencies
have been tightening NOx emission
standards over the last
decade 1,2.
A variety of NOx reduction
options, both catalytic and hardware
oriented, are available to
refiners to comply with limits on
NOx content emitted from the
FCCU regenerator flue gas
stream. One of the best methods
of meeting these regulations
is the use of low NOx combustion
promoters. This method
has the advantage of being
simple and inexpensive since it
replaces traditional Pt-based
promoter, and also typically
requires no additional infrastructure
or chemical reactants. In
addition, the U.S. Environmental
Protection Agency concluded
that newly adopted emission
limits utilizing additives and
combustion controls were
achievable, cost effective and
had fewer secondary impacts
14 ISSUE No. 107 / 2010
than more costly hardware oriented
control technologies 3.
The U. S. EPA issued final
amendments to its New Source
Performance Standards for
Petroleum Refineries (NSPS) 3
on June 24, 2008. Within this
amendment, the EPA states that
the currently Best Demonstrated
Technology (BDT) to NOx emission
control now includes the
use of additives in conjunction
with an upwardly revised NOx
emission limit of 80 ppmv based
on a 7-day rolling average.
Typically, under EPA Consent
Decree proceedings, FCCU
operations have been restricted
to a NOx emission limit of 20
ppmv based on a 365-day rolling
average and 40 ppmv based on
a 7-day rolling average. This
NSPS amendment now also recognizes
the secondary environmental
impact that many of the
hardware solutions inflict upon
the environment, inherent in
their operation to achieve a 20
ppmv maximum NOx emission
limit. These secondary impacts
include PM (Particulate Matter)
as well as additional SO 2 and
NOx emissions resulting from
increased electrical demand. In
addition, many of the hardware
solutions require supplementary
chemical reactants that add hazards
and emission problems of
their own 1. As such, non-platinum
formulated oxidation promoters
and advanced oxidation
controls typically are anticipated
to provide the least overall environmental
impact, as they generally
do not generate further
secondary environmental emissions.
Even though there are many
advantages for the use of low
NOx promoters, there are some
limitations, especially with first
generation promoters. These
include variable and at times limited
NOx reduction and also
occasionally low CO combustion
activity. The variability is thought
to be due to the wide range of
unit FCCU operating conditions,
as well as the variety of regenerator
configurations. The purpose
of this paper and the R&D
work at Grace is to understand
the reactions behind NOx formation
and destruction so improved
additives can be developed that
are more effective and less variable
in their performance. In
addition, work is on-going to
understand the operating conditions
that affect NOx formation in
order to develop recommendations
to help refiners optimize
their unit to minimize NOx.
NOx Emission Mechanism
NOx in the FCC regenerator
originates from feed nitrogen
being deposited on the catalyst
as coke. When the nitrogen
containing coke is burned off in
the regenerator, about 10% of
the nitrogen is emitted as NOx
and the remainder is emitted as
nitrogen. Thermal NOx, which
results from the oxidation of
molecular nitrogen (N 2), is not a
significant source of NOx at FCC
regenerator temperatures. This
has been shown to be the case
both by thermodynamic calculations
and experimentally by performing
a nitrogen mass balance
around an FCC pilot plant unit 4,5.
During the combustion of coke,
data indicates that the nitrogen
in the coke is first released as N 2
or as a reduced nitrogen compound,
such as HCN. In the
presence of water vapor, generated
by the combustion of coke,
the HCN is hydrolyzed to NH3 6,7.
These reduced nitrogen species
are then further oxidized to

Figure 1
Major NOx Reduction Pathways
Coke
Nitrogen
either N 2 or NOx. The NOx is
almost exclusively in the form of
NO. Once the NOx is formed it
can also react with various
reductants, such as carbon or
CO to form nitrogen.
In full burn units, traditional Ptbased
combustion promoters are
very effective at reducing CO but
also dramatically increase NOx
emissions. Low NOx combustion
promoters were introduced
to solve this problem by retaining
the CO oxidation function but
eliminating the sharp increase in
NOx. The low NOx combustion
promoters typically contain non-
Pt noble metals, potentially other
transition metals, and have modified
alumina supports that help
with the NOx reduction function
8,9,10.
Based on the reaction pathway
illustrated in Figure 1 for the formation
and destruction of NOx,
there are two major pathways by
which low NOx combustion promoters
can lower NOx. The first
(1) is catalyzing the reduction of
Reduced Nitrogen Species
(NH 3, HCN)
(2B)
(2A)
NOx + Reductant
(1)
Nitrogen
GRACE DAVISON CATALAGRAM 15

NOx to nitrogen. The second (2)
is acting on the NOx precursor
and minimizing its conversion to
NOx. This would be accomplished
by promoting the oxidation
of the reduced nitrogen
species to nitrogen (eqn. 2A)
rather than to NOx (eqn. 2B).
Equation 2A
4NH 3 + 3O 2 = 2N 2 + 6H 2O
Equation 2B
4NH 3 + 5O 2 = 4NO + 6H 2O
The first mechanism (1) has
been shown to be facilitated by
Grace combustion promoters.
This work is outlined in two
papers Grace published jointly
with researchers at the
University of South Carolina 11,12.
The data indicated that additives
promoted the reduction of NO by
CO through an isocyanate intermediate
stabilized by the surface
of the low NOx combustion promoter.
The second mechanism
(2), involving the oxidation of
reduced nitrogen species to
NOx, is the subject of work in
this paper. The research elucidating
these mechanisms and
the development of new Grace
low NOx combustion promoters
was carried out in a fluidized
bed Regenerator Test Unit as
well as in a fixed bed reactor, as
described below.
Experimental
Regenerator Test Unit
A laboratory scale Regenerator
Test Unit (RTU) was utilized to
test the performance of low NOx
combustion promoters and conditions
that affect NOx emissions
in the FCC regenerator 13. The
RTU simulates an FCC regener-
16 ISSUE No. 107 / 2010
ator by feeding coked catalyst
onto the top of a fluidized bed
where the coke is burned off
under controlled conditions.
Catalyst is also constantly
removed, generating an equilibrated
catalyst ranging from
completely coked to completely
regenerated catalyst in the reactor.
This closely replicates an
actual FCC regenerator environment
where additive performance
can be determined and
where regenerator conditions
can be systematically changed
to determine their effect on NOx
emissions.
The additives were tested after a
metals-free Cyclic Propylene
Steam (CPS) deactivation. The
commercial FCC catalyst used in
the study was steam deactivated
for 4 hours at 1500ºF in 100%
steam. After deactivation, it was
coked in Davison Circular Riser
pilot plant using an FCC feed
that contained 0.18 wt.% total
nitrogen, 0.42 wt.% sulfur, and
5.1 wt.% Conradson carbon.
The coked catalyst contained
approximately 1 wt.% coke. For
testing purposes, the deactivated
additive was blended with the
coked catalyst at a 0.2 wt.%
level. During testing the reactor
temperature was maintained at
700ºC, and the excess oxygen
was controlled at 1.1%. Data
were collected for 60 to 90 min
after the steady state was
achieved.
Fixed Bed Reactor
Fixed bed reactor work was carried
out, in collaboration with
University of South Carolina 14, to
compare the oxidation of the
reduced nitrogen species over a
variety of noble metals on a low
NOx combustion promoter base
support. Ammonia was used as
the model compound due to its
availability, relatively low toxicity
and belief that it is a major intermediate
species in the formation
of NOx. The metals were
deposited on the support using
soluble metal salts and impregnating
to incipient wetness. The
catalysts were dried and then
calcined. The oxidation of
ammonia in the presence of oxygen
was carried out at 700ºC to
simulate a typical FCC regenerator
temperature. For each
experiment 0.2 grams of additive
was blended with 3 grams of
quartz in the fixed bed. Prior to
analysis, the samples were treated
in a 10% O 2/He flow at
700ºC. The ammonia feed gas
concentration used for the reaction
was 500 ppm. The testing
was carried out using oxygen
levels of 500 ppm and 2000
ppm. The data were collected
under steady-state conditions at
constant gas hourly space velocity
(GHSV) of 30 L/gm/hr. The
reaction products from the reactor
were fed to a GC-mass spectrometer
for identification and
quantification.
Results
The oxidation of ammonia to
NOx and N 2 was carried out
over the low NOx combustion
promoter support as well as for
each of the supported metals.
The low NOx combustion promoter
support was considered
the base line and additional conversion
considered due to the
effect of the metal. The data in
Figure 2, for the 2000 ppm O 2
case shows that the Pt-based
promoter converts a significantly
higher percentage of ammonia
into NOx than either noble metal
#1 or #2. The noble metal #1
catalyst is the most selective for
converting NH 3 to N 2 followed by
noble metal #2 catalyst. These
results indicate that the selectivi-

ty of the combustion promoter in
catalyzing the oxidation of
reduced nitrogen species to
either N 2 or NO is a key difference
between the performance
of Pt and non-Pt promoters in
the FCC regenerator. The effect
of higher oxygen level on the
selective oxidation of NH 3 was
also studied. The data shows
that increasing oxygen levels
from 500 ppmv O 2 to 2000 ppmv
O 2, over the Pt promoter,
increases the amount of ammonia
converted to NOx by about
20%. Both of these observations
are consistent with what is
observed in FCC regenerators
where Pt-based promoters and
high excess O 2 levels both tend
to increase NOx emissions.
Resulting Products
CP ® P
Grace Davison’s third generation
low NOx combustion promoter,
CP ® P, has recently been introduced
to select refiners for commercial
scale evaluation.
Preliminary results from these
trials are confirming that the
intended characteristics of this
third generation low NOx combustion
promoter have been
achieved.
CP ® P has been designed as a
platinum free formulation, yielding
quick response to afterburn
and/or CO excursion situations,
as traditionally has been
observed with Pt formulated CO
promoters. Yet, CP ® P results in
lower NOx emissions and very
quick NOx emission decay periods.
While “rescue” dosing of Pt
formulated CO promoter would
often result in elevated and lingering
NOx emissions for up to
2-4 weeks, the NOx decay period
resulting from “rescue” dosing
of CP ® P tends to span only a
few days. Further, unlike earlier
Figure 2
NOx Formation vs. Noble Metal Type
NOx Formation (%)
70
60
50
40
30
20
10
0
generations of low NOx promoters,
CP ® P often does not
require strict adherence to daily
maintenance dosing. However,
consistent daily dosing of CP ® P
remains the preferred route
towards achieving predictable
afterburn, CO, and NOx emission
control and balance.
Below are the initially received
testimonial responses from
FCCU locations regarding the
performance characteristics of
CP ® P.
Wyoming Refining –
Newcastle, WY
“Wyoming Refining Company
has been a user of Grace
Davison’s CP ® 5 combustion
promoter since we started our
FCC up in 2000. We recently
switched to their CP ® P product
and are achieving the same
results as CP ® 5. Our reasoning
for the change was to help with
the reduction of NOx in our
regenerator flue gas. So far,
Pt Metal #2
Noble Metals
Metal #1
with the addition of CP ® P, we do
not see an increase in the NOx
whenever the Promoter is
added.”
Montana Refining –
Great Falls, MT
"We do see good results and
haven’t seen an increase in CO
with the amounts we have been
using."
The CP ® P usage rate is about
25% lower than the first generation
low NOx promoter. CP ® P is
more active with an immediate
afterburn and CO response, at
similar NOx levels, as with
XNOX ® .
Gulf Coast, USA Refiner
An immediate drop of 40-50°F in
regenerator cyclone temperatures
(at constant dense bed
temperatur) was observed after
the switch to CP ® P from a competitive
low NOX promoter.
GRACE DAVISON CATALAGRAM 17

Figure 3a
CO Combustion Activity
CO Combustion Activity (%)
100
90
80
70
60
50
40
30
20
10
0
Figure 3b
NOx Emission Comparison
NO Emissions (ppmv)
75
70
65
60
55
50
18 ISSUE No. 107 / 2010
CP ® P 4th Gen LNP
Combustion Promoters
CP ® P 4th Gen LNP
Combustion Promoters
The lower temperatures allowed
for a reduction in air rate and
excess O 2 in an FCCU that is air
rate limited during warmer
months. Thus providing the flexibility
to operate with lower preheat
and higher cat-to-oil ratios
during warmer weather. Previously,
operations would
attempt to increase air to oxidize
CO to CO 2 in the bed to keep
regenerator dilute phase temperature
in check.
Additionally, CP ® P, being a nonplatinum
formulated CO promoter,
greatly enhances the disposition
possibilities of a refiner’s
ecat. CP ® P is competitively
priced to attract FCCU operations
in need of either a low NOx
CO Promoter, or simply a
replacement to an existing mid
activity platinum formulated promoter.
Next Generation Low NOx
Promoter
Grace Davison’s continuing R&D
work on mechanistic pathways
for the formation and destruction
of NOx in the FCC regenerator,
indicate that additional improvements
to low NOx promoters are
still possible. Research and field
data show that there is a general
relationship between CO and
NO that makes it difficult to
achieve very low CO levels without
dramatically increasing NOx.
By fine-tuning and combining the
properties of an active metal and
the appropriate support material
we have preliminary data that
shows further reductions in NOx,
at constant CO levels, are
achievable. Testing data from
Grace Davison’s RTU, demonstrate
these improvements in
Figures 3A and 3B. The data
reveals that the CO combustion
activity of this fourth generation
promoter is similar to Pt-based

promoters and CP ® P but makes
lower NOx. We expect this new
technology will be commercialized
in 2011.
Summary
Grace research and development
efforts have led to the
development of CP ® P, a new
low NOx combustion promoter.
Data from multiple field trials has
indicated excellent CO control
with quick response to afterburn
and/or CO excursions, like traditional
Pt-based promoters.
However, unlike traditional promoters,
CP ® P provides lower
NOx emissions and very quick
NOx emission decay periods.
This new promoter was developed
as an outgrowth of R&D
work directed towards understanding
the mechanistic pathways
for NOx formation in the
FCC regenerator. The reduced
nitrogen species generated during
the burning of coke in the
regenerator are the key intermediate
species in minimizing NOx
formation. CP ® P is much more
effective at converting these
reduced species to N 2 than Ptbased
promoters, which tend to
convert them to NOx. In addition,
CP ® P is effective at converting
NOx that has been
formed in the regenerator back
to N 2 via a reaction with reducing
species.
Due to the success of low NOx
promoters and lack of need for
additional infrastructure or other
chemical reactants, these promoters
are now considered by
the EPA to be the Best
Demonstrated Technology for
abating NOx emissions from
FCC regenerators. Grace is
continuing work in alignment
with this BDT conclusion by the
EPA, directing continued
research and development
efforts towards further understanding
both the NOx formation
mechanisms and improved catalytic
methods for reducing NOx.
References
1. Frank S. Roser, Mark W. Schnaith, and
Patrick D. Walker, “Integrated View to
Understanding the FCC NOx Puzzle,” UOP
LLC, Des Plaines Illinois, 2004 AIChE Annual
Meeting.
2. Cheng, Wu-Cheng; Habib, E. Thomas,
Jr; Rajagopalan, Kuppuswamy; Roberie,
Terry G.; Wormsbecher, Richard F.; Ziebarth,
Michael S., Fluid Catalytic Cracking,
Handbook of Heterogeneous Catalysis (2nd
Edition) (2008), (6) 2741-2778.
3. New Source Performance Standards
(NSPS) for Petroleum Refineries, at 40
C.F.R. Part 60, Subpart J/Ja. 73 Fed. Reg.
35838 (June 24, 2008). The amendments
were proposed in 2007 as the outcome of
the periodic review of NSPS standards
required under the Clean Air Act -- Section
111(b)(1). 72 Fed. Reg. 27278 (May 14,
2007). The rules provide technical corrections
to the existing Subpart J standards and
create a set of new emissions for fluid catalytic
cracking units (FCCU), fluid coking
units (FCU), sulfur recovery plants (SRP),
and fuel gas combustion devices for facilities
that were newly constructed, modified or
reconstructed after May 14, 2007. The new
rules became effective on June 24, 2008.
4. Xinjin Zhao, A.W. Peters, G. W.
Weatherbee, Nitrogen Chemistry and NOx
Control in a Fluid catalytic Cracking
Regenerator, Ind. Eng. Chem. Res. 1997, 36,
4535-4542.
5. K. L. Dishman, P. K. Doolin, L. D.
Tullock, NOx Emissions in Fluid catalytic
Cracking Catalyst Regeneration, Ind. Eng.
Chem. Res. 1998,37, 4631-4636.
6. G. Yaluris,, A. Peters, Additives Acieve
Ultra-Low FCCU Emissions, NPRA Paper
AM-05-21, 2005
7. J. O. Barth, A. Jentys, J. A. Lercher, On
the Nature of Nitrogen Containing
Carbonaceous Deposits on Coked Fluid
Catalytic Cracking Catalysts, Ind. Eng.
Chem. Res. 2004,43, 2368-2375.
8. A.W. Peters, J.A. Rudesill, G.D.
Weatherbee, E.F. Rakeiwicz, M.J. Barbato-
Grauso, US Patent 6,143,167 2000, to
W.R.Grace & Co.-Conn.
9. A.W. Peters, E.F. Rakeiwicz, G.D.
Weatherbee, X. Zhao, US Patent 6,165,933
2000.
10. G. Yaluris, and J.A. Rudesill, US Patent
6,881,390, 2005.
11. Oleg S. Alexeev, Sundaram
Krishnamoorthy, Cody Jensen, Michael S.
Ziebarth, George Yaluris, Terry G. Roberie,
Michael D. Amiridis , In Situ FTIR
Characterization of the Adsorption of CO and
its Reaction with NO on Pd-Based FCC Low
NOx Combustion Promoters. Catalysis
Today, Volume 127, Issues 1-4, 30
September 2007, Pages 189-198.
12. Oleg S. Alexeev, Sundaram
Krishnamoorthy, Michael S. Ziebarth, George
Yaluris, Terry G. Roberie, Michael D.
Amiridis, Characterization of Pd-Based FCC
CO/NOx Control Additives by In Situ FTIR
and Extended X-ray Absorption Fine
Structure Spectroscopies. Catalysis Today,
Volume 127, Issues 1-4, 30 September 2007,
Pages 176-188.
13. G. Yaluris, X. Zhao, and A. W. Peters, “
FCCU Regenerator Lab-Scale Simulator for
testing New Catalytic Additives for Reduction
of Emissions from The FCC Regenerator”,
Proceedings of the 212th ACS National
Meeting, Orlando, FL, Aug, 1999, 41 (3)
P.901.
14. Michael Amiridis, Oleg Alexeev, Behnam
Bahrami (Chemical Engineering, University
of South Carolina), Udayshankar Singh,
Michael Ziebarth (W.R. Grace & Co.-Conn.),
Manuscript preparation currently in progress.
GRACE DAVISON CATALAGRAM 19

Grace Davison Introduces CP ® P,
Our Third Generation Non-Platinum
Low NOx CO Promoter
Our newest CO Promoter, CP ® P delivers quick
CO/afterburn response, equivalent to traditional
Platinum formulated promoters with up to 20%
lower NOx emissions compared to competitive
products.
Commercialized in late 2009, six FCC units are
currently using CP ® P and three additional trials are
planned. In commercial applications, CP ® P has
• 75% lower usage rates compared to first
generation low NOx promoter
• Allowed operation at lower excess O2 in an
air-limited FCCU
• An immediate 40 – 50°F drop in hottest cyclone
temperature at constant dense bed temperature
after switch from competitor
Its copper-free formulation allows for enhanced
disposition possibilities for equilibrium catalyst and
has no special handling requirements. CP ® P is
available in
• 5 lb. bags
• 30 lb. pails
• 300 lb. drums
• 2000 lb. totes
20 ISSUE No. 107 / 2010
Current
Users
Figure 1
CP ® P Reduces Variability
CO Index Percent
55
50
45
40
35
30
Table I
Current and Planned CP ® P Users
1
2
3
4
5
6
7
8
9
Date CP ® P
Started
Sep ‘09
Nov ‘09
Jan ’10
Feb ’10
Feb ’10
Feb ’10
Expected
Start 1st
Qtr 2010
Expected
Start 1st
Qtr 2010
Expected
Start 2nd
Qtr 2010
Reduced Variability with CP ® P
1st Generation Low NOx
Combustion Promoter
CP ® P
Base
Promoter
CP ® 5
XNOX ®
Competitor 2
Non-Pt Based
Promoter
Competitor 1
Non-Pt Based
Promoter
CP ® 5
CP ® 5
XNOX ®
CP ® A
Competitor 1
Non-Pt Based
Promoter

The Hidden
Economic Value
of FCC Additives
Improve FCC Revenues with
Light Olefin Additives
The refining industry is wellversed
in the use of ZSM-5 light
olefin additives for the incremental
production of propylene for
chemical and polymer applications
and butylenes for alkylation
unit feedstock. However, light
olefin additives are also capable
of providing significant flexibility
in operating the FCC unit. There
are a number of scenarios when
using light olefin additives may
provide an overall economic
benefit.
Grace recently experienced one
such scenario when a refiner
took an early turnaround on a
catalytic reformer. The refinery
was octane short at this point
and there was no opportunity to
increase riser temperature.
Grace recommended that the
refiner consider the use of light
olefins additive to boost the
overall octane from the FCC
complex. The use of ZSM-5
increases the yield of C 3 and C 4
olefins to feed the alkylation unit
and any other units designed to
create gasoline range material
from FCC olefins. The incremental
light olefin production
from the FCC results in higher
alkylate yields. Alkylate is a
refinery blending stream that is
high in both motor and research
octane. At the same time, the
yield of FCC gasoline generally
drops at constant riser temperature,
but the octane is increased,
with general increases ranging
from 0.3 to 0.7 numbers.
When the total octane properties
of the FCC gasoline and alkylate
are added together, there is an
increase in the octane of the
total gasoline pool from the FCC
complex. This is a valuable economic
option when the FCC unit
is running at reduced feed rates
and there is available capacity in
the alkylation unit. By varying
the concentration of light olefin
additive added to the circulating
catalyst inventory, the refiner can
independently optimize the riser
outlet temperature at the alkylation
unit maximum feed capacity.
This option may be especially
helpful in the fall and winter,
when higher LCO yields are
generally desirable.
Grace Davison is the leading
supplier of high activity, high stability
ZSM-5 FCC additives.
OlefinsMax ® additive and
OlefinsUltra ® additive are being
used in over 50 FCC units worldwide.
They continue to provide
economic value for the refiner by
generating incremental propylene,
additional feed for alkylation
and an increase in gasoline
octane.
GRACE DAVISON CATALAGRAM 21

Distillate Pool Maximization
by Additional LCO Hydroprocessing
Brian Watkins
Technical Service
Engineer
Advanced Refining
Technologies
Chicago, IL
FCC light cycle oil (LCO) has
long been a common component
of feed to diesel hydrotreaters
and more recently, there has
been greater interest in processing
higher quantities of LCO due
to economic considerations and
to meet the market demand for
ULSD products. Increasing the
quantity of LCO to the diesel
hydrotreater has a number of
impacts both on the performance
of the hydrotreater and on
22 ISSUE No. 107 / 2010
David Krenzke, Ph.D
Regional Technical
Services Manager
Advanced Refining
Technologies
Richmond, CA
the resulting ULSD product properties.
Additional LCO has the
combined effect of lowering the
diesel pool cetane as well as
limiting end of run (EOR) by
making it difficult to maintain
diesel ASTM color specifications.
This paper will discuss several
options refiners have in using
the additional LCO while gaining
back both end of cycle life as
well as the needed cetane
improvements.
Charles Olsen, Ph.D.
Worldwide Technical
Services Manager
Advanced Refining
Technologies
Chicago, IL
The extent of the impact of LCO
depends upon a number of factors
including the amount and
endpoint of LCO in the feed, and
the catalyst used in the ULSD
unit 1. These challenges can be
overcome with proper choice of
catalyst system and an understanding
of the impact LCO has
on both unit performance and
ULSD product quality.

It is generally accepted that the
addition of LCO to the diesel
increases feed severity and
requires an increase in reactor
temperature in order to meet the
product sulfur target. Figure 1
summarizes pilot plant data
demonstrating this effect. The
figure shows the required temperature
increase relative to the
straight run (SR) feed as a function
of the fraction of LCO in the
feed ranging from 0 to 75%
LCO. It is clear that even low
levels of LCO can impact catalyst
activity. At high severity
(

Figure 2
Product Total Aromatics at Varying LCO Concentrations
Total vol.% Aromatics
70
60
50
40
30
20
10
0
660 680 700 720 740 760
WABT, ˚F
Figure 4
Product Total Aromatics with Varying LCO
Concentration & SRO Catalyst
Total vol.% Aromatics
45
40
35
30
25
20
15
10
5
25% 50% 75% 0%
Figure 3
Product PNA Content at Varying LCO Concentrations
2+ vol.% Aromatics
18
16
14
12
10
8
6
4
2
0
660 680 700 720 740 760
WABT, ˚F
0
680 690 700 710 720 730 740 750 760
24 ISSUE No. 107 / 2010
25% 50% 75% 0%
WABT, ˚F
25% 50% 75% 0%
Figure 2 shows how increasing
the concentration of LCO in the
feedstock can affect the total
aromatic content of the product.
The base SR feedstock used in
this case has 1.1 wt.% sulfur,
27.2 vol.% total aromatics and
9.5 vol.% poly aromatics. The
LCO that was blended into this
feed contained 2.01 wt.% sulfur,
538 ppm nitrogen, 67 vol.% total
aromatics and 51.3 vol.% poly
aromatics. In this case ART’s
high activity NDXi catalyst was
used in an effort to provide maximum
aromatic conversion. As
the figure shows, there is a limit
to the amount of aromatic saturation
that can be achieved.
The poly aromatic content of the
products can also be a concern,
due to a much higher starting
concentration and the thermodynamic
equilibrium constraint on
conversion as the hydrotreater
reaches the end of run. Figure 3
shows how the product PNA’s
vary with reactor temperature
and fraction of LCO in the feed.
The equilibrium constraint at
high temperature is readily
apparent.
With the use of a selective ring
opening (SRO) catalyst ART is
able to improve the hydro-treaters
ability to meet product total aromatic
and PNA targets. These
same feedstocks discussed
above were also tested using a
system containing NDXi and a
layer of selective ring opening catalyst
at the bottom of the
hydrotreater. The catalyst system
provided the same HDS and HDN
activity, and showed the ability to
process additional LCO while
achieving higher aromatic saturation
conversion compared to the
hydrotreating catalyst alone.
Figure 4 shows the product total
volume percent aromatics with
the same four feedstocks.

The use of a ring opening catalyst
provides an additional
decrease in total aromatic content,
especially with the 50% and
75% LCO feedstocks. This benefit
is also apparent at the higher
temperatures with reduced product
PNA concentrations relative
to the hydrotreating catalyst
alone as shown in Figure 5.
Looking at just the 75% LCO
feedstock and comparing the
two catalyst systems, the benefit
is more obvious as shown in
Figure 6 for both total aromatics
and PNA concentrations.
The new SmART Catalyst
System ® series with SRO catalyst
capability is very effective for
reducing aromatic rings which
translates to improved cetane
and color performance. The aromatic
reduction performance of
both systems is shown in Figure
7 which compares the two systems
at 10 ppm sulfur.
Aromatics and Cetane
Table I lists some pure compounds
and their corresponding
cetane number. As can be
seen, paraffins, particularly normal
paraffins, have very high
cetane numbers while aromatics,
especially naphthalene type aromatics,
have very low cetane
numbers. Certain distillate
range materials like FCC LCO
are high in naphthalenes which
explains the low cetane number
of LCO feedstocks.
A survey of commercial operating
units shows there are a number
of operating parameters
which influence cetane improvement
in a diesel hydrotreater,
most notably hydrogen partial
pressure, liquid hourly space
velocity (LHSV) and feed API
gravity (i.e. amount of LCO).
Figure 5
Product PNA’s with Varying LCO
Concentration & SRO Catalyst
2+ vol.% Aromatics
7
6
5
4
3
2
1
25% 50% 75% 0%
0
680 690 700 710 720 730 740 750 760
Vol.% Aromatics
60
50
40
30
20
10
0
WABT, ˚F
Figure 6
Catalyst Comparison at 75% LCO in Feedstock
Figure 7
Product Aromatics
Vol.%
40
35
30
25
20
15
10
5
0
680˚F
700˚F
720˚F
740˚F
NDXi NDXi/SRO NDXi
NDXi/SRO
TOTAL PNA
Total Aromatics PNA
Feed
NDXi
NDXi/SRO
GRACE DAVISON CATALAGRAM 25

Table I
Cetane Number of Pure Compounds
Parrafins
Isoparaffins
Naphthenes
Aromatics
Figure 8
Cetane Index of Various Distillate Feeds
Cetane Index (D976)
60
55
50
45
40
35
30
25
20
15
LCO
LCGO/VBGO
Straight Run
Kerosene
Compound
n-Decane
n-Pentadecane
n-Hexadecane
n-Eicosane
3-Ethyldecane
4,5-Diethyloctane
Heptamethylnonane
8-Propylpentadecane
7,8-Diethyltetradecane
9,10-Dimethyloctadecane
Decalin
3-Cyclohexylhexane
2-Methyl-3-cyclohexylnonane
2-Cyclohexyltetradecane
1-Methylnaphthalene
n-Pentylbenzene
Biphenyl
1-Butylnaphthalene
n-Nonylbenzene
2-Octylnaphthalene
n-Tetradecylbenzene
Formula
C10H22
C15H32
C16H34
C20H42
C12H26
C12H26
C16H34
C18H38
C18H38
C20H42
C10H18
C12H24
C16H32
C20H40
C11H10
C11H16
C12H10
C14H16
C15H24
C18H24
C20H34
Cetane
Number
76
95
100
110
48
20
15
48
67
59
48
36
70
57
0
8
21
6
50
18
72
10
5 10 15 20 25 30 35 40 45 50
Feed API
26 ISSUE No. 107 / 2010
Generally speaking, as LHSV
decreases the potential cetane
improvement increases.
Commercial ULSD experience
has shown that for LHSV’s
around 1 hr -1 or less, cetane
increases (as measured by
cetane index, ASTM D-976) of
about 10 numbers are achievable
provided the H 2 pressure is
high enough when processing
LCO blends. At higher LHSV’s
(greater than about 1.7 hr -1) the
potential cetane improvement
decreases to about 4 numbers
or less. Not surprisingly, higher
pressure units tend to achieve
much larger cetane increases. It
has been observed that the
cetane uplift is typically less than
6 numbers when the unit pressure
is less than 1000 Psig while
the cetane uplift increases to 8-
10 numbers as pressure increases
beyond 1000 Psig. A more
detailed discussion can be found
in reference 2.
Figure 8 compares the cetane
index (D976) for a number of different
distillate feed sources. It
is readily apparent that FCC
LCO’s have the lowest cetane
while SR materials have the
highest cetane. Distillate feeds
derived from coking operations
tend to have a cetane similar to
SR material, while kerosene
tends to have somewhat lower
cetane owing to the lower boiling
point. For the diesel range
materials, the feeds with lower
API gravity (LCO) have lower
cetane index demonstrating that
within a given boiling range the
API is a reasonable tool for estimating
the cetane index.
Figure 9 is a summary of commercial
data from a ULSD unit
using a SmART System which
operates at about 1300 Psig and
slightly under 1 LHSV. The feed
blend varies from 100% cracked

stocks to 100% straight run
material. As the figure shows,
the feed API gravity has a major
effect on the cetane upgrade.
At low feed API gravities (high
LCO levels) the cetane index
increase achieved in this unit is
around 9 numbers compared to
6 numbers or less for low (or no)
LCO included in the feed (higher
feed API gravities).
As might be expected, there is
an increased cost in hydrogen to
achieving high cetane increases
from feeds containing high proportions
of LCO. Figure 10
shows how the H 2 consumption
increases with increasing cetane
uplift from the same commercial
ULSD unit. For cetane number
increases of 5-8 numbers the H 2
consumption is consistent with
the rule of thumb that H 2 consumption
equals roughly 100*
∆cetane. Notice, however, that
getting increases beyond the 8
numbers in this case come at a
very large increase in H 2 consumption;
at 9-9.5 numbers of
cetane improvement the H 2 consumption
is over 1200 SCFB, a
30% increase in H 2 consumption
per incremental cetane number.
This suggests there is a practical
limit to the cetane improvement
achievable for a given set of
feed, operating conditions and
catalyst system. In this example
it looks to be about 8 numbers.
The majority of this increase in
traditional cetane upgrading is
due to the saturation of poly aromatic
compounds with some
moderate amount of mono aromatic
saturation. As was shown
in Table I, the saturation of poly
aromatic compounds can result
in reasonable increases in
cetane.
Figure 9
Cetane Increase Observed in a Commercial ULSD Unit
Cetane Index Increase
10.0
9.5
9.0
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35
Cetane Index Increase
10
9
8
7
6
5
4
500
Feed API Gravity
Figure 10
H 2 Consumption Increases with Cetane Uplift
600 700 800 900 1000 1100 1200 1300
H 2 Consumption
GRACE DAVISON CATALAGRAM 27

Figure 11
The Catalyst System Has a Huge Impact
on Cetane Uplift
Cetane Index Increase
15
14
13
12
11
10
9
8
7
6
5
Figure 12
Cetane Index Improvement
Cetane Index Improvement
H2 Consumption/Unit Cetane
Improvement, SCFB
12
10
NiMo CoMo SmART
4
620 625 630 635 640 645 650 655 660 665 670
8
6
4
2
0
100
95
90
85
80
Temperature, ˚F
NDXi NDXi/SRO
Figure 13
Hydrogen Consumption for Cetane Index Improvement
28 ISSUE No. 107 / 2010
NDXi NDXi/SRO
As mentioned previously, the
catalyst system has a significant
impact on the degree of cetane
uplift achieved in a hydrotreater.
It is common knowledge that
NiMo catalysts have a higher
saturation activity than CoMo
catalysts, and therefore the
NiMo catalyst is expected to
deliver greater cetane uplift.
Figure 11 summarizes pilot plant
data which demonstrate this.
These data were generated
using a 50% LCO containing
feed, and show that the NiMo
catalyst results in almost twice
the cetane uplift compared to the
CoMo catalyst. The SmART
System, which utilizes both the
CoMo and NiMo catalyst, results
in a cetane uplift which is nearly
two numbers higher than the all
CoMo system with only a small
increase in hydrogen consumption.
For H 2 constrained refiners
this is an ideal solution for
improving the product cetane.
Both cetane and color improvement
are related to aromatic ring
removal. Saturating aromatic
rings is an effective way to
improve cetane, but there is a
practical limit to the amount of
cetane uplift that can be
achieved as was shown in
Figure 4. Furthermore, the reaction
may become thermodynamically
limited near the end of the
cycle resulting in a lower level of
cetane uplift and possible color
problems. A better approach is
aromatic saturation followed by
selective ring opening. The
resulting paraffinic product has a
higher cetane than the corresponding
saturated ring as seen
in Table I and avoids the issue of
thermodynamic control at the
end of the run. ART is developing
a selective ring opening catalyst
for use in high pressure
hydrotreaters which target

cetane improvement. The following
figures show the results of
this new system compared to a
high activity NiMo catalyst,
NDXi.
Pilot testing was carried out
using a diesel feed containing
25% LCO at 1.0 LHSV, 1240 psi
H 2 pressure, and 3000 SCFB
H 2/Oil. The WABT for both catalyst
systems was the same and
resulted in 8-10 ppm sulfur product.
Figure 12 shows the cetane
index improvement for each system.
Commercial experience in ULSD
has shown that units processing
feeds containing high fractions
of LCO and other cracked
stocks, or units with insufficient
hydrogen, can experience
decreasing cetane uplift as the
catalyst ages. The use of an
SRO catalyst system will help to
Table II
GC-Mass Spec Analysis of ULSD Products from Different Catalyst Systems
Saturates
Total Aromatics
Mono Aromatics
Poly Aromatics
Thiophenic Compounds, wt.%
Carbon
Hydrogen
Avg Carbon number
mitigate this effect and improve
EOR cetane and product color.
Certainly one of the key considerations
with the greater cetane
improvement is efficient use of
hydrogen. The commercial data
in Figure 4 show that at cetane
uplifts >8 numbers, the H 2
requirement for incremental
cetane improvement increases
significantly. Figure 13 gives the
H 2 consumption per unit cetane
number increase for NDXi and
the NDXi/SRO system.
Even though the NDXi/SRO system
gives a cetane improvement
of >11 numbers, the H 2 usage is
more efficient than with typical
hydrotreating.
Table II compares the ULSD
products from the two systems
at

Figure 14
ULSD Product Color from Commercial Unit
Product Color, ASTM
3.5
3.0
2.5
2.0
1.5
1.0
0.5
0.0
580 600 620 640 660 680 700 720 740 760 780
Outlet Temperature, ˚F
Figure 15
Comparison of Product Color for SR and 30% LCO
ASTM Color
4.0
3.5
3.0
2.5
2.0
1.5
1.0
0.5
30 ISSUE No. 107 / 2010
SR
LCO
800 Psig
1200 Psig
1200 Psig
800 Psig
0.0
640 660 680 700 720 740 760 780 800
Temperature, ˚F
have also been implicated as
problems for distillate product
color and product instability.
Work conducted by Ma et.al. 3
concluded that the specific
species responsible for color
degradation in diesel are
anthracene, fluoranthene and
their alkylated derivatives. Other
work completed by Takatsuka
et.al. 4 showed that the color
bodies responsible for diesel
product color degradation were
concentrated in the higher boiling
points in the diesel (>480°F)
suggesting that color can be
improved by adjusting the diesel
endpoint.
PNA’s such as these are readily
saturated to one and two ringed
aromatics under typical diesel
hydrotreating conditions at start
of run (SOR), but as the temperature
of the reactor increases
towards EOR, an equilibrium

constraint is reached whereby
the reverse dehydrogenation
reaction becomes more and
more favorable. At some combination
of ‘low’ hydrogen partial
pressure and ‘high’ temperature,
PNA’s actually begin to form (or
reform) resulting in a degradation
of the diesel product color.
Figure 14 summarizes data from
a commercial ULSD unit using
ART catalysts. The data show
that the product color exceeded
2.5 ASTM, the pipeline color
specification for diesel, at reactor
outlet temperatures above
730°F. The feed to this unit contained
30-50% LCO and it was
operated at 1.0 LHSV and 850
Psig inlet pressure.
Figure 15 summarizes some
pilot plant data which were generated
as part of a larger color
study using spent CDXi, a premium
CoMo catalyst for ULSD 5.
The figure shows a comparison
of the diesel product color
achieved from an SR feed and a
30% LCO blend at 2100 SCFB
H 2/Oil ratio and two pressures.
The SR feed results in acceptable
color over the wide range of
temperatures and for both pressures
shown. The product from
the LCO blend, on the other
hand, goes off color (>2.5
ASTM) between 730-740°F at
800 Psig while at 1200 Psig the
temperature can exceed 760°F
before going off color. This
clearly demonstrates the significant
impact that H 2 partial pressure
has on diesel product color
when processing LCO containing
feeds.
Figure 16 compares the product
color achieved from NDXi and
the NDXi/XRO system from the
pilot study discussed above.
The SmART system using the
SRO catalyst gives a 0.5 num-
Figure 16
Product Color
ASTM Color
2
1.5
1
0.5
0
ber ASTM color benefit over the
NiMo only system. This
improvement in product color
allows refiners the option to run
additional LCO or to add life at
the end of the cycle before the
products no longer meet the
ASTM color specifications.
Advanced Refining Technologies
(ART) is well positioned to provide
assistance on how best to
maximize unit performance and
to take advantage of opportunities
to successfully process
more LCO into ULSD. ART has
developed catalysts specifically
designed to handle more difficult
feeds exemplified by the SmART
technology for ULSD. The technology
has been widely accepted
with over 75 units in
commercial service since its
inception. Advanced Refining
Technologies ® continues to
improve its line of ultra high
activity ULSD catalysts, and the
addition of an SRO catalyst to
the ULSD catalyst portfolio will
provide refiners with greater flexibility
in the operation of their
diesel hydrotreating units.
NDXi NDXi/SRO
References
1. B. Watkins and C.Olsen, 2009 NPRA
Annual Meeting, paper AM-09-78
2. G.Rosinski and C.Olsen, Catalagram ®
publication No. 106, Fall 2009
3. X. Ma et. al., Energy and Fuels, 10, pp
91-96 (1996)
4. T.Takatsuka et.al., 1991 NPRA Annual
Meeting, Paper AM-91-39
5. G.Rosinski, B.Watkins and C.Olsen,
Catalagram ® publication No. 105, Spring
2009
GRACE DAVISON CATALAGRAM 31

32 ISSUE No. 107 / 2010
People on the Move
Mike Federspiel has moved to Singapore for a sales/technical
service rotation in Asia Pacific. Mike will report to Lim Tow Foon.
In a related move, Cher Yee Young has joined the North American
Tech Service team, reporting to Dennis Kowalczyk.
Kevin Burton joined our Technical Sales team covering North American
West Coast accounts, reporting to Mike Zehender. Kevin comes with
close to twenty years of experience in the petroleum, refining and chemical
industries, most recently at Hovensa where he spent the last eleven
years on the process engineering, technical service, and project development
teams.
Leonid Leznik has been promoted to Al’s position of Director of Sales
Operations, Refining Technologies. Leonid has worked in key roles at
Grace for the last 17 years, most recently as a Technical Sales
Representative for the North American Sales team, He will be a member
of the RT Leadership Team, reporting to Shawn Abrams, Vice-
President and General Manager.

People on the Move
CONTINUED FROM PAGE 34
Woody Shiflett is named to the new role of Deputy Managing Director
for Advanced Refining Technologies. In this role, Woody will have
responsibility for ART’s technology functions,maintaining his current
responsibilities for Marketing and Technical Service and now adding
responsibility for Research & Development. We expect this arrangement
will allow for closer cooperation and interaction between these functions
leading to benefits in product development and customer support.
Ingrid Du has completed Grace's Marketing Leadership Program rotation
and accepted a full-time role on the ART marketing team reporting
to Scott Purnell. Additionally, she will work closely with Woody Shiflett
and Lauren Blanchard.
Olivia Topete joins us as a Technical Service Representative. She
comes to us from Merichem where she spent four years as a Process
and Mechanical Design Supervisor in their Process Technologies division,
and previously spent 5 years at UOP as a Field Advisor commissioning
UOP technologies globally. Olivia graduated with an MBA
from Rice University, and has her undergraduate degree from Purdue
in Chemical Engineering.
Al Jordan has been named to the newly expanded role of Grace Davison’s Operations
Director, Asia Pacific. Our manufacturing sites in this region will report to Al, who will be located
in Singapore. Al was formerly RT’s Director of Sales Operations.
GRACE DAVISON CATALAGRAM 33

Salt Deposition in
FCC Gas Concentration Units
Michel Melin
Director
Technical Service
Grace Davison Refining
Technologies
Europe, Middle East and Africa
Various operational problems
can arise when ammonium chloride
deposition occurs in FCC
gas concentration units, and
there is a range of likely causes.
Salt deposition in FCC gas concentration
units can lead to various
operational problems if it is
not dealt with in an appropriate
manner. It is therefore important
for refiners to be aware of the
34 ISSUE No. 107 / 2010
Colin Baillie
Marketing Manager
Grace Davison
Refining Technologies
Europe, Middle East and Africa
main causes of salt deposition
so that the correct procedures
can be applied to manage this
phenomenon.
Introduction
Troubleshooting of FCCUs in
terms of cyclone problems, catalyst
circulation issues or coking
has been discussed in much
detail. 1 However, less informa-
Gordon McElhiney
Director Marketing &
Business Development
Grace Davison
Refining Technologies
Europe, Middle East and Africa
tion has been reported about
ways of dealing with salt deposition
issues. The salt that is
deposited most in FCC gas concentration
units is ammonium
chloride (NH 4Cl), but deposits
can also occur of the salts
ammonium hydrosulfide
(NH 4)SH and iron sulfide (FeS),
although they are less common.

This article is intended to provide
refiners with useful information
regarding the most likely
causes of salt deposition, the
associated symptoms and resulting
consequences, as well as
approaches that can be taken to
handle such situations. The
Grace Davison Refining
Technologies technical service
team has helped various refiners
manage the issue of salt deposition
and this valuable experience
will be discussed.
Ammonium Chloride
Deposition: Likely Causes
There are two reasons for an
increasing occurrence of ammonium
chloride deposits. First,
refiners are processing a higher
amount of residue feedstocks,
which typically have a higher
chloride content. Some refiners
are also bypassing the desalter
with imported atmospheric
residue feedstock, which contributes
to higher feed chloride
levels. Second, due to the need
to produce low-sulfur gasoline, a
gasoline side cut is extracted
from the main fractionator (MF)
and subsequently hydrotreated.
This leads to main fractionator
top temperatures as low as
100°C (212˚F), compared to previous
temperatures in the range
of 135-145°C (275-293˚F).
While these are the most likely
origins of ammonium chloride
deposits, there are other circumstances
that can cause this
problem and a summary is listed
in Table I.
During troubleshooting for a salt
deposition issue, all of these
possibilities should be considered,
individually and in combination.
For example, one
refinery that experienced issues
with ammonium chloride deposi-
tion performed such a troubleshooting
exercise, and the
problem was finally attributed to
the injection of slop to the main
fractionator. This slop was rich in
chloride and, together with the
effects of acidic crudes that were
being processed, resulted in
ammonium chloride deposition
on the fractionator (with severe
corrosion of the fractionator
packing, see Table III). The problem
of salt deposition was
solved by water washing (see
Table IV).
Chloride Contribution from the
FCC Catalyst
In addition to the incorporation of
rare-earth chloride into FCC catalysts
to stabilize the zeolite and
steer product selectivities, chlo-
Table I
Most Likely Causes of Ammonium
Chloride Salt Deposition
ride is an integral feature of the
Grace Davison Al-sol binder system,
which was first commercialised
in the early 1980s, with
the Worms plant in Germany
being the pioneer site. This Alsol
binder system provides the
basis for formulation flexibility
which generates the high performance
associated with Grace
Davison FCC catalysts. Indeed
the uniqueness of this binder
system is one of the main reasons
why Grace Davison FCC
catalysts have maintained a performance
advantage over other
catalyst suppliers. The question
as to whether chloride from this
binder can contribute to salt deposition
is occasionally raised,
and in this context the following
facts are relevant.
Processing of imported atmospheric residue
Poor crude desalter operation
Recovery of a MF gasoline side cut (lower top temperature)
Reprocessing of slops in MF
Leaking overhead condenser (using sea water)
Overflowing overhead receiver water boot
Bad distribution of cold reflux stream (cold spot)
Feedstocks containing organic chloride from additives used to increase
the recovery of oil or for cleaning
GRACE DAVISON CATALAGRAM 35

During the FCC catalyst manufacturing
process, the Al-sol
binder is “set” using a high temperature
calcination to provide
attrition resistance over a wide
range of formulations. This hightemperature
calcination step
also removes most (>80%) of
the chloride from the catalyst. If
necessary, additional processing
steps can be used to further
reduce the fresh catalyst chloride
content. In use, the fresh
catalyst is added to the FCCU
via the regenerator, and it is
important to recognize that typi-
cal temperatures in the FCCU
regenerator are significantly
higher than those used in calcination
in the standard catalyst
manufacturing process, which in
turn are higher than typical reactor
temperatures in the FCCU. In
“The main type of salt deposited is
ammonium chloride and there is a range of
likely causes.”
consequence, and accelerated
by the steam which is also present,
chloride remaining on the
fresh FCC catalyst is very quickly
removed in the regenerator
before the catalyst makes its first
transit to the reactor section.
Typically 80-95% of the fresh
catalyst chloride is removed in
Figure 1
Diagram Highlighting Where Ammonium Chloride Deposition Can Occur
Reactor
vapours
36 ISSUE No. 107 / 2010
Deposition can
occur at
top of MF...
Main
Fractionator
HCO
recycle
Overhead
coolers
...and in the
overhead line
Filter
Water
LCO
Stripper
Steam
Overhead
receiver
To wet gas compressor
Wild naphtha to
primary absorber
Rich sponge oil
To sponge oil absorber
Hydrotreater
the FCCU flue gas, depending
on the regenerator design. It is
therefore recommended to avoid
adding the fresh catalyst to a
zone where it can bypass the
regenerator bed and travel
directly to the riser/stripper.
Ammonium Chloride
Deposition - Symptoms and
Consequences
Ammonium chloride deposition
takes place primarily at the top
of the main fractionator, although
it can be encountered to a lesser
extent in the overhead line,
where the gas is passed through
the air and water coolers, or the
downstream FCC gas plant.
Figure 1 shows a schematic diagram
of where ammonium chloride
deposition is most likely to
occur.
Light cycle oil
(LCO) product
Decanted oil product

The main symptom of ammonium
chloride deposition is an
increase in pressure drop at the
top of the main fractionator.
Further symptoms are listed in
Table II.
Salt deposition can cause a
reduction in feedrate as well as
a slight deterioration of product
quality. This can be a consequence
of the salt deposition
itself, but will also temporarily be
observed during any resulting
period of water wash applied to
reduce the salt deposition. In
addition, corrosion may also be
an issue especially for packed
columns. A summary of the consequences
of salt deposition are
highlighted in Table III.
Managing and Solving the
Issues of Ammonium Chloride
Deposition
The Grace Davison Refining
Technologies technical service
team has worked with refiners to
help solve ammonium chloride
deposition issues, and the experience
gained is shared in the
following main recommendations.
To prevent ammonium chloride
deposition in the overhead line,
water is usually added, with typical
quantities in the range of 6-7
vol.% water on a fresh feed
basis.
Addition of an anti-fouling additive
in the reflux stream can prevent
the formation of ammonium
chloride deposits on the trays
and packing. The salt is carried
instead with the gasoline stream,
in which it is insoluble. Such
additives have been used successfully
to reduce ammonium
chloride salt deposition in various
refineries over the last ten
years; for instance, at the
Table II
Main Symptoms of Salt Deposition
Increase in MF delta P
Flooding of MF top section
Plugging of top products draws
Loss of duty of pump around heat exchangers
Loss of separation efficiency between gasoline and LCO
Higher MF bottom temperature
Increase in reactor/regen pressure
Plugging of reflux/gasoline pump strainer
Reduced reflux/TPA rate
Wider opening of WGC suction valve
Difficulty when using HCN for reboiling depropanizer because the HCN
temperature is lower and salt may deposit in the tubes
Table III
Consequences of Salt Deposition
Corrosion of trays/packing
Reduced WGC capacity (lower suction P)
Reduced air blower capacity (higher regen P)
Increased unit delta coke (higher reactor P)
Fouling of slurry circuit (if higher bottom T)
Poor quality heavy gasoline
Cost associated with reduced feed rate and off spec products
during periodic water wash
Lower duty of depropanizer reboiler
Lower duty of debutanizer reboiler
Pembroke refinery in south
Wales, UK, as well as the
Mongstad refinery in Norway. 2,3
These additives are now considered
established and effective
technology. They are also said to
protect against corrosion.
Another recommendation is
water wash the main fractionator.
Water is injected either periodically
or (more rarely)
continuously in the reflux
stream, and the main fractionator
top temperature is reduced to
approximately 80°C (176˚F)
using the reflux rate or the tip
top pumparound, to allow water
to condense inside the column
to dissolve the salt. The water is
preferably removed on a dedicated
tray, where it is separated
from the heavy cracked naphtha.
This procedure has been suc-
GRACE DAVISON CATALAGRAM 37

cessfully practised by Saudi
Aramco. 4 Alternatively the main
fractionator top temperature can
be increased (for instance, to
above 135°C (275˚F)) for a
given period of time to enable
dissociation of the salt.
Obviously, this results in a fullrange
gasoline leaving overhead
during the time period.
Other recommendations include
improving water settling in
imported feed tanks by allowing
more time and the use of additives.
Hardware modifications could
include the design of the main
fractionator’s reflux distributor to
avoid cold spots at the top of the
column. Alternatively the main
fractionator’s tray design could
be revised. For example, the
installation of a water boot in
one of the trays will allow water
(and the dissolved salt) to be
removed without contaminating
the heavy cracked naphtha. The
installation of a two-stage
desalter could also be considered
to optimize the operation of
the crude desalter unit. Other
options include the installation of
a dedicated FCC feed desalter, 5
or the installation of a gasoline
splitter and then collecting the
thermally cracked naphtha overhead
of the main fractionator.
Finally, a very effective solution
is to hydrotreat the FCC feed, as
this removes most of the feed
chloride and significantly
improves the yield structure.
However, this requires a large
capital investment.
The main methods for managing
ammonium chloride deposition
are highlighted in Table IV.
38 ISSUE No. 107 / 2010
Table IV
Methods for Managing Ammonium Chloride
Salt Deposition
Use of anti-fouling additives
Water washing of the MF
Increased MF top temperature
Improved water settling in imported feed tanks
Modification of MF reflux distributor to avoid cold spots at the top of the column
Installation of a water boot in one of the MF trays
Installation of a two-stage crude desalter
Installation of a FCC feed desalter
Installation of a gasoline splitter
Hydrotreating the FCC feed
Avoid adding FCC catalyst in a zone where it can bypass the regenerator bed

Ammonium Chloride Deposition in the Main Fractionator
Consider an FCC unit processing atmospheric residue feedstock under the following conditions:
• Feed rate = 440 tonne/h (440 000 kg/h) (968,000 lb/hr)
• Feed nitrogen content = 1645 ppmw
• Feed chloride content = 1.93 ppmw
• MF top pressure = 1.89 bara (27.8 psig)
• Steam to the MF = 50.5 tonne/h = 2806 kmol/h
• Dry gas = 53584 Nm3/h = 2392 kmol/h
• LPG = 100.3 tonne/h = 1937 kmol/h
• LCN+reflux = 344.2 tonne/h = 3843 kmol/h
• Total flow to the MF top = 10 978 kmol/h
The following example assumes that 15% of the feed nitrogen goes to NH 3
• the production of nitrogen (from the feed) = 440 000 × 0.1645 wt.%
= 723.8 kg/h
= 51.7 kmol/h
• the resulting production of ammonia = 51.7 × 15%
= 7.79 kmol/h
• the partial pressure of NH 3
= 1.89 × (7.79/10978)
= 1.34 × 10-3 bara
• the production of chloride (from the feed) = 440 000 × 0.000193 wt.%
= 0.85 kg/h
= 2.4 × 10-2 kmol/h
• The partial pressure of HCl = 1.89 × (2.4 × 10-2/10978)
= 4.13 × 10-6 bara
• ppNH 3 × ppHCl = 5.53 × 10-9 bara
Using the following formula:
ln (Kp) = - 21183.4/T + 34.17
where Kp = ppNH 3 × ppHCl, and T is the minimum main fractionator top temperature required to
avoid salt deposition (measured in ˚K), the minimum top temperature required to avoid salt deposition
under these conditons is 125°C (257˚F).
GRACE DAVISON CATALAGRAM 39

Other Types of Salt
Deposition
The other main types of salt
deposition are from ammonium
hydrosulfide and iron sulfide.
The deposition of ammonium
hydrosulfide is controlled by the
equilibrium reaction:
NH 3 (g) + H 2S (g)
40 ISSUE No. 107 / 2010
(NH 4)SH (s)
and takes place at a lower temperature
than for ammonium
chloride. 6 Deposition of this salt
is most likely to occur in the
overhead line coolers and sometimes
in the wet gas compressor
itself, particularly when processing
feeds with high nitrogen and
sulphur contents. The deposition
of (NH 4)SH is best controlled by
adjusting the temperature where
the deposition occurs, as well as
by the use of a water wash.
Iron sulfide is a corrosion product,
which, to a large extent, is
found on the main fractionator
trays and packing. Since the salt
is pyrophoric, its accumulation is
a potential hazard during the
opening of the column. It has
been reported that the additives
used to prevent ammonium chloride
deposition also help prevent
the accumulation of iron sulfide
in the main fractionator. Proper
procedures for shutdown of the
FCCU, and the application of a
chemical wash to oxidize the
iron sulfide prior to vessel entry,
should be considered. 7
Conclusion
Various operational problems
can arise when salt deposition
occurs in FCC gas concentration
units. The main type of salt
deposited is ammonium chloride
and there is a range of likely
causes, with the increased processing
of imported atmospheric
residue being a major contributor.
The vast majority of FCCU’s
using alumina-sol based FCC
catalysts never experience problems
due to the chloride content
associated with this binder. It is
important to clarify, moreover,
that there are a number of ways
to manage and solve any issues
of ammonium chloride deposition.
Indeed, various refineries
have enlisted the support of the
Grace Davison Refining
Technologies technical service
team with respect to chloride
management, so that they can
avoid having to change to a
chloride-free FCC catalyst, with
the resulting sacrifice in performance
and economics.
References
1. Mott, R. W., Troubleshooting FCC
Standpipe Flow Problems. Catalagram ® publication
No. 83, p.25-35, 1992.
2. Minyard, W. F., and Martin, D. O.,
Removal and Prevention of Salt Fouling in
FCC Main Fractionators, ERTC Conference,
Rome, Italy, Nov. 13-15 , 2000.
3. Minyard, W. F., and Martin, D. O.,
Hansen, A. S., Synnevag, L., FCC Main
Fractionator Salt Fouling Solutions,
Hydrocarbon Engineering, March, 2000.
4. Dean, C., Golden, S. W., Main
Fractionator Water Wash Systems, PTQ
Revamps, p.23-25.
5. Xiaodong, Y. E., Gasoil Desalting
Reduces Chlorides in Crude, Oil and Gas
Journal, Oct 16, 2000, p.76-78.
6. Yiing, M. W., Calculations Estimate
Process Stream Depositions, Oil and Gas
Journal, Jan 3, 1994, p.38-41.
7. Ender, C., and Laird, D., Reduce the
Risk of Fire During Distillation Column
Maintenance, World Refining, November
2002, p.30-35.

Grace Davison Refining Technologies
Units that are circulation limited can’t take full advantage of improved feed quality. When
the FCC catalyst is not active enough regenerator temperatures become too low and
desired reactor temperatures can’t be achieved. Some refiners resort to burning torch oil
or recycling slurry to provide additional delta coke which is often detrimental to the opera-
tion. Alcyon provides superior activity and stability while maintaining excellent coke and
dry gas selectivity. Alcyon is Grace Davison’s latest invention proving once again. We don’t just make FCC
catalysts, we make FCC catalysts for you. www.e-catalysts.com
www.grace.com
Alcyon : A New FCC Star Emerges
Grace Davison introduces Alcyon, a revolutionary new FCC catalyst
designed for maximum activity.
W. R. Grace & Co. - Conn.
7500 Grace Drive
Columbia, MD 21044 USA
+1 410.531.4000
Grace GmbH & Co. KG
In der Hollerhecke 1
67545 Worms, Germany
+49 624.140.300
W. R. Grace Singapore PTE Ltd.
501 Orchard Road
#07-02 Wheelock Place
Singapore 238880
+65 6737.5488
Grace ® and Grace Davison ® are trademarks, in the United States and/or other countries, of W. R. Grace & Co.-Conn. The information presented herein is derived from our testing and experience. It is offered, free of charge, for your
consideration, investigation and verification. Since operating conditions vary significantly, and since they are not under our control, we disclaim any and all warranties on the results which might be obtained from the use of our products.
You should make no assumption that all safety or environmental protection measures are indicated or that other measures may not be required. © 2010 W. R. Grace & Co.-Conn.

© 2010 W. R. Grace & Co.-Conn.
Catalagram ®, Grace ®, Grace Davison ®, GENESIS ®, MIDAS ®, IMPACT ®, GSR ®, AURORA ®, ADVANTA ®, Super DESOX ®, D-PriSM ®,
SuRCA ®, GSR ®-5, OlefinsMax ®, OlefinsUltra ® and SmART Catalyst System ® are registered trademarks in the United States and/or
other countries, of W. R. Grace & Co.-Conn.
ApART, AT, DX and StART, SmART Catalyst System ® are trademarks of Advanced Refining Technologies, LLC.
ART ® and ADVANCED REFINING TECHNOLOGIES ® are trademarks, registered in the United States and/or other countries,
of Advanced Refining Technologies, LLC.
Astera and Alcyon are trademarks of W. R. Grace & Co.-Conn.
Grace Davison ® is a business unit of W. R. Grace & Co.-Conn.
This trademark list has been compiled using available published information as of the publication date of this brochure and may not
accurately reflect current trademark ownership.
The information presented herein is derived from our testing and experience. It is offered, free of charge, for your consideration,investigation and
verification. Since operating conditions vary significantly, and since they are not under our control, we disclaim any and all warranties on the results
which might be obtained from the use of our products. You should make no assumption that all safety or environmental protection measures are
indicated or that other measures may not be required.
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