ASTM D7206/D7206M-06(2013)e1
(Guide)Standard Guide for Cyclic Deactivation of Fluid Catalytic Cracking (FCC) Catalysts with Metals
Standard Guide for Cyclic Deactivation of Fluid Catalytic Cracking (FCC) Catalysts with Metals
SIGNIFICANCE AND USE
3.1 This guide describes techniques of deactivation that can be used to compare a series of cracking catalysts at equilibrium conditions or to simulate the equilibrium conditions of a specific commercial unit and a specific catalyst.
SCOPE
1.1 This guide covers the deactivation of fluid catalytic cracking (FCC) catalyst in the laboratory as a precursor to small scale performance testing. FCC catalysts are deactivated in the laboratory in order to simulate the aging that occurs during continuous use in a commercial fluid catalytic cracking unit (FCCU). Deactivation for purposes of this guide constitutes hydrothermal deactivation of the catalyst and metal poisoning by nickel and vanadium. Hydrothermal treatment is used to simulate the physical changes that occur in the FCC catalyst through repeated regeneration cycles. Hydrothermal treatment (steaming) destabilizes the faujasite (zeolite Y), resulting in reduced crystallinity and surface area. Further decomposition of the crystalline structure occurs in the presence of vanadium, and to a lesser extent in the presence of nickel. Vanadium is believed to form vanadic acid in a hydrothermal environment resulting in destruction of the zeolitic portion of the catalyst. Nickel’s principle effect is to poison the selectivity of the FCC catalyst. Hydrogen and coke production is increased in the presence of nickel, due to the dehydrogenation activity of the metal. Vanadium also exhibits significant dehydrogenation activity, the degree of which can be influenced by the oxidation and reduction conditions prevailing throughout the deactivation process. The simulation of the metal effects that one would see commercially is part of the objective of deactivating catalysts in the laboratory.
1.2 The two basic approaches to laboratory-scale simulation of commercial equilibrium catalysts described in this guide are as follows:
1.2.1 Cyclic Propylene Steaming (CPS) Method, in which the catalyst is impregnated with the desired metals via an incipient wetness procedure (Mitchell method)2 followed by a prescribed steam deactivation.
1.2.2 Crack-on Methods, in which fresh catalyst is subjected to a repetitive sequence of cracking (using a feed with enhanced metals concentrations), stripping, and regeneration in the presence of steam. Two specific procedures are presented here, a procedure with alternating metal deposition and deactivation steps and a modified Two-Step procedure, which includes a cyclic deactivation process to target lower vanadium dehydrogenation activity.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: D7206/D7206M − 06 (Reapproved 2013)
Standard Guide for
Cyclic Deactivation of Fluid Catalytic Cracking (FCC)
Catalysts with Metals
This standard is issued under the fixed designation D7206/D7206M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorially changed 8.2.1.1 in March 2013.
1. Scope 1.2.2 Crack-onMethods,inwhichfreshcatalystissubjected
to a repetitive sequence of cracking (using a feed with
1.1 This guide covers the deactivation of fluid catalytic
enhancedmetalsconcentrations),stripping,andregenerationin
cracking (FCC) catalyst in the laboratory as a precursor to
the presence of steam. Two specific procedures are presented
small scale performance testing. FCC catalysts are deactivated
here, a procedure with alternating metal deposition and deac-
in the laboratory in order to simulate the aging that occurs
tivation steps and a modified Two-Step procedure, which
during continuous use in a commercial fluid catalytic cracking
includesacyclicdeactivationprocesstotargetlowervanadium
unit (FCCU). Deactivation for purposes of this guide consti-
dehydrogenation activity.
tutes hydrothermal deactivation of the catalyst and metal
poisoning by nickel and vanadium. Hydrothermal treatment is 1.3 The values stated in either SI units or inch-pound units
used to simulate the physical changes that occur in the FCC
are to be regarded separately as standard. The values stated in
catalyst through repeated regeneration cycles. Hydrothermal each system may not be exact equivalents; therefore, each
treatment (steaming) destabilizes the faujasite (zeolite Y),
system shall be used independently of the other. Combining
resulting in reduced crystallinity and surface area. Further values from the two systems may result in non-conformance
decomposition of the crystalline structure occurs in the pres-
with the standard.
ence of vanadium, and to a lesser extent in the presence of
1.4 This standard does not purport to address all of the
nickel. Vanadium is believed to form vanadic acid in a
safety concerns, if any, associated with its use. It is the
hydrothermal environment resulting in destruction of the
responsibility of the user of this standard to establish appro-
zeolitic portion of the catalyst. Nickel’s principle effect is to
priate safety and health practices and determine the applica-
poison the selectivity of the FCC catalyst. Hydrogen and coke
bility of regulatory limitations prior to use.
production is increased in the presence of nickel, due to the
dehydrogenation activity of the metal. Vanadium also exhibits
2. Terminology
significant dehydrogenation activity, the degree of which can
2.1 Definitions:
be influenced by the oxidation and reduction conditions pre-
2.1.1 crack-on—technique of depositing metals onto a cata-
vailing throughout the deactivation process. The simulation of
lyst through cracking of an FCC feed with enhanced metal
the metal effects that one would see commercially is part of the
content in a fluidized catalyst bed that is at cracking tempera-
objective of deactivating catalysts in the laboratory.
ture.
1.2 The two basic approaches to laboratory-scale simulation
2.2 Acronyms:
of commercial equilibrium catalysts described in this guide are
2.2.1 E-cat—equilibrium catalyst from commercial FCCU.
as follows:
1.2.1 Cyclic Propylene Steaming (CPS) Method, in which
2.2.2 FCC—fluid catalytic cracking.
the catalyst is impregnated with the desired metals via an
2.2.3 FCCU—fluid catalytic cracking unit.
incipient wetness procedure (Mitchell method) followed by a
2.2.4 LGO—light gas oil, fluid at 40°C, initial boiling point
prescribed steam deactivation.
< 200°C, sulfur content < 1 mass percent.
2.2.5 VGO—vacuum gas oil, fluid at 70°C, initial boiling
This guide is under the jurisdiction ofASTM Committee D32 on Catalysts and
point > 250°C, sulfur content of 2 to 3 mass percent.
is the direct responsibility of Subcommittee D32.04 on Catalytic Properties.
Current edition approved March 1, 2013. Published March 2013. Last previous
edition approved in 2012 as D7206/D7206M–06(2012)e1. DOI: 10.1520/D7206_ 3. Significance and Use
D7206M-06R13E01.
3.1 This guide describes techniques of deactivation that can
Mitchell, B. R., Industrial and Engineering Chemistry Product Research and
Development, 19, 1980, p. 209. be used to compare a series of cracking catalysts at equilibrium
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D7206/D7206M − 06 (2013)
conditions or to simulate the equilibrium conditions of a mixed to dryness.After drying, the sample is thermally treated
specific commercial unit and a specific catalyst. to remove residual naphthenates. The sample is then ready for
hydrothermal treatment of analysis as desired.
4. Reagents
6.2 Procedure:
4.1 Feed, VGO.
6.2.1 Catalyst Pre-treatment Before Impregnation—For a
muffle furnace pre-treatment (standard), place the sample in a
4.2 Feed, LGO.
dish using a shallow bed ( ⁄2 in. maximum). Calcine the sample
4.3 Hydrogen (H ), 42.8 % in nitrogen balance.
for1hat 204°C [400°F], then3hat 593°C [1100°F]. The
4.4 Nickel naphthenate or nickel octoate solution.
sample is then removed and allowed to cool to room tempera-
ture. Catalyst should be returned to a sealed container as soon
4.5 Nitrogen (N ).
as it is cool.
4.6 Oxygen (O ), 40 % in nitrogen balance.
6.2.2 Steam Deactivation Pre-treatment—Typical condi-
4.7 Vanadium naphthenate solution.
tions included hydrothermal treatment for2hat 816°C
[1500°F], 100 % steam, and 0 psi. The catalyst is charged to a
4.8 Cyclohexane.
pipereactor,fluidizedinair,andthenloweredovera3-hperiod
4.9 n-pentane.
into a 816°C [1500°F] sand bath furnace. Air flow is switched
4.10 n-hexane.
off and steam introduced for 2 h. The reactor is then removed
from the furnace and allowed to cool to room temperature
4.11 Water, demineralized.
under a nitrogen purge.
5. Hazards 6.2.3 Preparation of Nickel and Vanadium Mixture—The
desired nickel/vanadium levels are calculated for the quantity
5.1 The operations described in this guide involve handling
of sample to be impregnated. The mass of nickel or vanadium
heated objects, fragile glassware, and toxic organic nickel and
naphthenate used to obtain the desired levels on the catalyst
vanadium compounds.
sample are determined as follows:
5.2 All work with organic metals precursor solutions and
N 5 T/S 3W (1)
other organic solvents should be completed in suitable vented
fume hood.
where:
N = naphthenate (nickel or vanadium mass used to obtain
5.3 Appropriate personal protection equipment, including
the desired metal level on the catalyst),
chemical goggles, laboratory smock, and disposable gloves
T = target level (the desired mass percent of nickel or
should be worn.
vanadium, or both, to be loaded on the catalyst),
5.4 Waste organic metal solutions and organic solvents shall
S = metal solution (the known mass percent of nickel or
be disposed of properly in suitable waste containers and
vanadium in the naphthenate solution), and
according to regulations.
W = mass of catalyst sample to be impregnated.
5.5 Vented furnaces and hoods should be regularly moni-
6.2.4 Impregnation:
tored for proper ventilation before using.
6.2.4.1 Catalyst is poured into an evaporating dish.The dish
5.6 Evaporating dishes should be checked for cracks before
shall be large enough to allow for a catalyst bed height of ⁄2 in.
use.
6.2.4.2 Slowly pour the dissolved metals solution into the
dish with catalyst while mixing at the same time. Wash the
5.7 The muffle furnace used for the post-impregnation
residual naphthenate from the glass beaker with pentane and
thermal treatment of the sample shall be appropriately and
add the wash to the catalyst.
adequately ventilated. Catalyst load sizes should be selected to
6.2.4.3 Stir the sample with a spoonula until it is completely
avoidoverwhelmingtheventilationcapacityofthefurnaceand
dry. The appearance of very small lumps in the catalyst after
allowing fumes to escape into the laboratory.
drying is normal. Large lumps indicate improper drying and
5.8 To avoid the potential hazard of explosion in the muffle
shall be avoided. This can be done by adding enough pentane
furnace, impregnated samples shall be completely dry of
to moisten the catalyst then repeating the stirring process. High
pentane prior to beginning the thermal post-treatment.
levelsofvanadiumnaphthenatewillcausethesampletoappear
5.9 Material safety data sheets (MSDS) for all materials
gummy and is normal.
used in the deactivation should be read and understood by
6.2.4.4 High Levels of Vanadium Naphthenate—When an
operators and should be kept continually available in the
impregnation calls for more than 5000 ppm vanadium, the
laboratory for review.
impregnation should be done in two steps. Otherwise, the
volume of naphthenate will overwhelm the volume of catalyst
6. CPS Method
used, affecting the accuracy in reaching the target level. If over
6.1 Summary of Practice—A fresh FCC catalyst is impreg- 5000 ppm vanadium is required, divide the required volume of
nated with nickel, or vanadium, or both. Nickel and vanadium vanadium naphthenate in half, impregnate, post-treat, and
levels are controlled by a predetermined concentration for the impregnate again by adding the second half followed by a
sample. The catalyst is wetted with a mixture of pentane and second post-treat. If nickel is also requested, this should be
nickel, or vanadium naphthenate, or solutions of both and then divided and added to the catalyst along with the vanadium.
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D7206/D7206M − 06 (2013)
6.2.4.5 Antimony Addition—If antimony is requested, triph- 7.2.2.2 Individually add the organic metal compounds. The
enylantimony is added to the catalyst after the nickel and massofeachmetaladdedshallbecalculatedtogivethedesired
vanadium have been added and the post treatment has been metalloadingonthecatalyst.Ifusingthistechniquetoperform
completed. The impregnation procedure is the same as the an E-cat simulation, the metal target may have to be substan-
nickel and vanadium impregnation except that cyclohexane is tially reduced by 25 to 50 % of the actual E-cat metal content
usedinsteadofpentane.Antimonywillnotdissolveinpentane. in order to simulate the deactivation effects discussed in the
6.2.5 CatalystPost-treatmentAfterImpregnation—Afterthe scope.
impregnated sample has dried, it is placed in a vented muffle 7.2.2.3 Stir the LGO with a mechanical stirrer, and option-
furnace and heat treated to remove the naphthenates and coke
ally heat, to insure homogeneity of the mixture throughout the
formed. The dishes are placed in the furnace at room tempera- procedure.
ture and the temperature is raised to 204°C [400°F] and held at
7.2.3 Set up the Reactor System:
temperature for 1 h. The sample is then calcined at 593°C
7.2.3.1 Load the catalyst into the fluidized bed reactor. The
[1100°F] for 3 h before being removed and allowed to cool to
amount of catalyst charged depends on the geometry of the
room temperature.
reactor vessel.
6.2.6 Steam Deactivation—Several methods exist, each re-
7.2.3.2 Attach all external control, input, exhaust and safety
quiring specific conditions. An example of such a method is
devices.
shown in Table 1.
7.2.3.3 Fill the water reservoir to the appropriate starting
point.
7. Crack-on Approach 1: Alternating Cracking and
7.2.3.4 Start the flow of 100 % nitrogen gas through the
Deactivation Cycles
LGO feed tube.
7.1 Summary of Practice:
7.2.3.5 Start the flow of 100 % nitrogen through the sieve
7.1.1 The crack-on units consist of a fluid bed reactor with
plate.
a fritted gas distributor on the bottom. Nitrogen, air, steam and
7.2.4 Metallation and Regeneration:
other specialty gasses can be fed through the bottom. Oil can
7.2.4.1 Set the reactor temperature (500 to 530°C).
be delivered either from the top or bottom of the reactor
7.2.4.2 Inject xx grams of the LGO prepared in 7.2.2 (xx =
depending on the method. Temperature is controlled by a three
total mass LGO / number of cycles). A good rule of thumb
zone electric furnace. A disengaging section on the top of the
might be to set LGO per cycle equivalent to 20 to 50 % of the
reactor prevents catalyst loss during operation.
catalyst mass.
7.1.2 The crack-on method involves depositing metals on
7.2.4.3 Run a stripping cycle with pure nitrogen (no feed)
thecatalystatcrackingtemperatureusingafeedwithenhanced
for 7 to 10 min, while ramping temperature to regeneration
metals content. The catalyst is regenerated after each cracking
conditions (600 to 700°C).
cycle.
7.2.4.4 After the stripping step is complete, change the gas
7.1.3 In Crack-on Approach 1, the catalyst is subjected to
composition through both the feed tube and sieve plate to
severe hydrothermal deactivation after each cracking and
100 % air for regeneration.
regenerationcycle.Bythismethod,significantdeactivationhas
7.2.5 Deactivation:
taken place by the time the metals addition is complete.
7.2.5.1 Deactivationtimeandtemperaturearespecifictothe
7.2 Procedure:
objectives of the catalyst simulation (732 to 815°C). The total
7.2.1 Preparation of the Catalyst—Optionally screen the
deactivation time from start to finish is established to achieve
catalyst to remove coarse contaminants and fine particles that
a certain degree of surface area reduction. Therefore, the
would be lost during fluidization.
steaming time per cycle is variable, but typically 30 to 60 min.
7.2.2 Prepare the Feed:
7.2.5.2 Ramp the temperature up to deactivation conditions.
7.2.2.1 Weigh out and transfer the appropriate amount of
7.2.5.3 Terminate the air gas flow through the feed tube and
LGO into the feed vessel. The minimum amount of LGO will
the sieve plate.
equal the number of cracking cycles times the amount fed per
7.2.5.4 Activate the water pump and adjust the water flow
cycle.
rate to achieve the desired partial pressure of steam. 100 %
steam is achievable, but 45 to 90 % is more typical for
TABLE 1 Standard CPS Procedure
laboratory simulations.
7.2.5.5 Repeat steps 7.2.3.4 through 7.2.5.4 for the number
NOTE 1—This scheme is considered standard and represents the case in
of desired cycles.
which the treatment ends in a state of reduction. A similar scheme in
which the cycles end in oxidation can also be configured.
7.2.6 At the conclusion of the final deactivation step, cool
Catalyst pre-treatment 1 h at 204°C [400°F] followed by3hat 593°C [1100°F]
the fur
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