ASTM D7206-06
(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
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. Nickels 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) Methodin which the catalyst is impregnated with the desired metals via an incipient wetness procedure (Mitchell method) 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 SI units are to be regarded as the standard. The values given in parentheses are for information only.
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:D7206–06
Standard Guide for
Cyclic Deactivation of Fluid Catalytic Cracking (FCC)
Catalysts with Metals
This standard is issued under the fixed designation D7206; 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.
1. Scope the presence of steam. Two specific procedures are presented
here, a procedure with alternating metal deposition and deac-
1.1 This guide covers the deactivation of fluid catalytic
tivation steps and a modified Two-Step procedure, which
cracking (FCC) catalyst in the laboratory as a precursor to
includesacyclicdeactivationprocesstotargetlowervanadium
small scale performance testing. FCC catalysts are deactivated
dehydrogenation activity.
in the laboratory in order to simulate the aging that occurs
1.3 The values stated in SI units are to be regarded as
during continuous use in a commercial fluid catalytic cracking
standard. The values given in parentheses are for information
unit (FCCU). Deactivation for purposes of this guide consti-
only.
tutes hydrothermal deactivation of the catalyst and metal
1.4 This standard does not purport to address all of the
poisoning by nickel and vanadium. Hydrothermal treatment is
safety concerns, if any, associated with its use. It is the
used to simulate the physical changes that occur in the FCC
responsibility of the user of this standard to establish appro-
catalyst through repeated regeneration cycles. Hydrothermal
priate safety and health practices and determine the applica-
treatment (steaming) destabilizes the faujasite (zeolite Y),
bility of regulatory limitations prior to use.
resulting in reduced crystallinity and surface area. Further
decomposition of the crystalline structure occurs in the pres-
2. Terminology
ence of vanadium, and to a lesser extent in the presence of
2.1 Definitions:
nickel. Vanadium is believed to form vanadic acid in a
2.1.1 crack-on—technique of depositing metals onto a cata-
hydrothermal environment resulting in destruction of the
lyst through cracking of an FCC feed with enhanced metal
zeolitic portion of the catalyst. Nickel’s principle effect is to
content in a fluidized catalyst bed that is at cracking tempera-
poison the selectivity of the FCC catalyst. Hydrogen and coke
ture.
production is increased in the presence of nickel, due to the
2.2 Acronyms:
dehydrogenation activity of the metal. Vanadium also exhibits
2.2.1 E-cat—equilibrium catalyst from commercial FCCU.
significant dehydrogenation activity, the degree of which can
2.2.2 FCC—fluid catalytic cracking.
be influenced by the oxidation and reduction conditions pre-
2.2.3 FCCU—fluid catalytic cracking unit.
vailing throughout the deactivation process. The simulation of
2.2.4 LGO—light gas oil, fluid at 40°C, initial boiling point
the metal effects that one would see commercially is part of the
< 200°C, sulfur content < 1 mass percent.
objective of deactivating catalysts in the laboratory.
2.2.5 VGO—vacuum gas oil, fluid at 70°C, initial boiling
1.2 The two basic approaches to laboratory-scale simulation
point > 250°C, sulfur content of 2-3 mass percent.
of commercial equilibrium catalysts described in this guide are
as follows:
3. Significance and Use
1.2.1 Cyclic Propylene Steaming (CPS) Method, in which
3.1 This guide describes techniques of deactivation that can
the catalyst is impregnated with the desired metals via an
2 beusedtocompareaseriesofcrackingcatalystsatequilibrium
incipient wetness procedure (Mitchell method) followed by a
conditions or to simulate the equilibrium conditions of a
prescribed steam deactivation.
specific commercial unit and a specific catalyst.
1.2.2 Crack-onMethods,inwhichfreshcatalystissubjected
to a repetitive sequence of cracking (using a feed with
4. Reagents
enhancedmetalsconcentrations),stripping,andregenerationin
4.1 Feed, VGO.
4.2 Feed, LGO.
This guide is under the jurisdiction ofASTM Committee D32 on Catalysts and
4.3 Hydrogen (H ), 42.8 % in nitrogen balance.
is the direct responsibility of Subcommittee D32.04 on Catalytic Properties.
4.4 Nickel naphthenate or nickel octoate solution.
Current edition approved April 1, 2006. Published April 2006. DOI: 10.1520/
4.5 Nitrogen (N ).
D7206-06.
4.6 Oxygen (O ), 40 % in nitrogen balance.
Mitchell, B. R., Industrial and Engineering Chemistry Product Research and
Development, 19, 1980, p. 209.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D7206–06
4.7 Vanadium naphthenate solution. from the furnace and allowed to cool to room temperature
4.8 Cyclo-hexane. under a nitrogen purge.
4.9 N-pentane.
6.2.3 Preparation of Nickel and Vanadium Mixture—The
4.10 N-hexane.
desired nickel/vanadium levels are calculated for the quantity
4.11 Water, demineralized.
of sample to be impregnated. The mass of nickel or vanadium
naphthenate used to obtain the desired levels on the catalyst
5. Hazards
sample are determined as follows:
5.1 The operations described in this guide involve handling
N 5 T/S 3 W (1)
heated objects, fragile glassware, and toxic organic nickel and
vanadium compounds.
where:
5.2 All work with organic metals precursor solutions and
N = naphthenate (nickel or vanadium mass used to obtain
other organic solvents should be completed in suitable vented the desired metal level on the catalyst),
fume hood. T = target level (the desired mass percent of nickel or
5.3 Appropriate personal protection equipment, including vanadium, or both, to be loaded on the catalyst),
S = metal solution (the known mass percent of nickel or
chemical goggles, laboratory smock, and disposable gloves
vanadium in the naphthenate solution), and
should be worn.
W = mass of catalyst sample to be impregnated.
5.4 Waste organic metal solutions and organic solvents shall
be disposed of properly in suitable waste containers and 6.2.4 Impregnation:
according to regulations.
6.2.4.1 Catalyst is poured into an evaporating dish.The dish
5.5 Vented furnaces and hoods should be regularly moni-
shall be large enough to allow for a catalyst bed height of ⁄2 in.
tored for proper ventilation before using.
6.2.4.2 Slowly pour the dissolved metals solution into the
5.6 Evaporating dishes should be checked for cracks before
dish with catalyst while mixing at the same time. Wash the
use.
residual naphthenate from the glass beaker with pentane and
5.7 The muffle furnace used for the post-impregnation
add the wash to the catalyst.
thermal treatment of the sample shall be appropriately and
6.2.4.3 Stir the sample with a spoonula until it is completely
adequately ventilated. Catalyst load sizes should be selected to
dry. The appearance of very small lumps in the catalyst after
avoidoverwhelmingtheventilationcapacityofthefurnaceand
drying is normal. Large lumps indicate improper drying and
allowing fumes to escape into the laboratory.
shall be avoided. This can be done by adding enough pentane
5.8 To avoid the potential hazard of explosion in the muffle
to moisten the catalyst then repeating the stirring process. High
furnace, impregnated samples shall be completely dry of
levelsofvanadiumnaphthenatewillcausethesampletoappear
pentane prior to beginning the thermal post-treatment.
gummy and is normal.
5.9 Material safety data sheets (MSDS) for all materials
6.2.4.4 High Levels of Vanadium Naphthenate—When an
used in the deactivation should be read and understood by
impregnation calls for more than 5000 ppm vanadium, the
operators and should be kept continually available in the
impregnation should be done in two steps. Otherwise, the
laboratory for review.
volume of naphthenate will overwhelm the volume of catalyst
used, affecting the accuracy in reaching the target level. If over
6. CPS Method
5000 ppm vanadium is required, divide the required volume of
6.1 Summary of Practice—A fresh FCC catalyst is impreg-
vanadium naphthenate in half, impregnate, post-treat, and
nated with nickel, or vanadium, or both. Nickel and vanadium
impregnate again by adding the second half followed by a
levels are controlled by a predetermined concentration for the
second post-treat. If nickel is also requested, this should be
sample. The catalyst is wetted with a mixture of pentane and
divided and added to the catalyst along with the vanadium.
nickel, or vanadium naphthenate, or solutions of both and then
6.2.4.5 Antimony Addition—If antimony is requested, triph-
mixed to dryness.After drying, the sample is thermally treated
enylantimony is added to the catalyst after the nickel and
to remove residual naphthenates. The sample is then ready for
vanadium have been added and the post treatment has been
hydrothermal treatment of analysis as desired.
completed. The impregnation procedure is the same as the
6.2 Procedure:
nickel and vanadium impregnation except that cyclohexane is
6.2.1 Catalyst Pre-treatment Before Impregnation—For a
usedinsteadofpentane.Antimonywillnotdissolveinpentane.
muffle furnace pre-treatment (standard), place the sample in a
6.2.5 Catalyst Post-treatment After Impregnation—After
dish using a shallow bed ( ⁄2 in. maximum). Calcine the sample
the impregnated sample has dried, it is placed in a vented
for1hat 204°C (400°F), then3hat 593°C (1100°F). The
muffle furnace and heat treated to remove the naphthenates and
sample is then removed and allowed to cool to room tempera-
coke formed. The dishes are placed in the furnace at room
ture. Catalyst should be returned to a sealed container as soon
temperatureandthetemperatureisraisedto204°C(400°F)and
as it is cool.
held at temperature for 1 h. The sample is then calcined at
6.2.2 Steam Deactivation Pre-treatment—Typical condi-
593°C (1100°F) for 3 h before being removed and allowed to
tions included hydrothermal treatment for2hat 816°C
cool to room temperature.
(1500°F), 100 % steam, and 0 psi. The catalyst is charged to a
pipereactor,fluidizedinair,andthenloweredovera3-hperiod 6.2.6 Steam Deactivation—Several methods exist, each re-
into a 816°C (1500°F) sand bath furnace. Air flow is switched quiring specific conditions. An example of such a method is
off and steam introduced for 2 h. The reactor is then removed shown in Table 1.
D7206–06
TABLE 1 Standard CPS Procedure
7.2.3.4 Start the flow of 100 % nitrogen gas through the
LGO feed tube.
NOTE—This scheme is considered standard and represents the case in
7.2.3.5 Start the flow of 100 % nitrogen through the sieve
which the treatment ends in a state of reduction. A similar scheme in
which the cycles end in oxidation can also be configured. plate.
7.2.4 Metallation and Regeneration:
Catalyst pre-treatment 1 h at 204°C (400°F) followed by3hat 593°C (1100°F)
Impregnation 2000 ppm nickel and 3000 ppm vanadium
7.2.4.1 Set the reactor temperature (500-530°C).
Post-treatment 1 h at 204°C (400°F) followed by3hat 593°C (1100°F)
7.2.4.2 Inject xx grams of the LGO prepared in 7.2.2 (xx =
Steam deactivation 788°C (1450°F), 50% steam, 0 psig, 20 h (30 cycles)
Cycles consist of: 10 min, 50% mass percent N total mass LGO / number of cycles). A good rule of thumb
10 min, 50% mass percent 4000 ppm SO in air
might be to set LGO per cycle equivalent to 20-50 % of the
10 min, 50 mass percent N
catalyst mass.
10 min, 50 mass percent propylene-N mixture
(5% propylene in N )
7.2.4.3 Run a stripping cycle with pure nitrogen (no feed)
for 7-10 min, while ramping temperature to regeneration
conditions (600-700°C).
7.2.4.4 After the stripping step is complete, change the gas
7. Crack-on Approach 1: Alternating Cracking and
composition through both the feed tube and sieve plate to
Deactivation Cycles
100 % air for regeneration.
7.1 Summary of Practice:
7.2.5 Deactivation:
7.1.1 The crack-on units consist of a fluid bed reactor with
7.2.5.1 Deactivationtimeandtemperaturearespecifictothe
a fritted gas distributor on the bottom. Nitrogen, air, steam and
objectives of the catalyst simulation (732-815°C). The total
other specialty gasses can be fed through the bottom. Oil can
deactivation time from start to finish is established to achieve
be delivered either from the top or bottom of the reactor
a certain degree of surface area reduction. Therefore, the
depending on the method. Temperature is controlled by a three
steaming time per cycle is variable, but typically 30-60 min.
zone electric furnace. A disengaging section on the top of the
7.2.5.2 Ramp the temperature up to deactivation conditions.
reactor prevents catalyst loss during operation.
7.2.5.3 Terminate the air gas flow through the feed tube and
7.1.2 The crack-on method involves depositing metals on
the sieve plate.
thecatalystatcrackingtemperatureusingafeedwithenhanced
7.2.5.4 Activate the water pump and adjust the water flow
metals content. The catalyst is regenerated after each cracking
rate to achieve the desired partial pressure of steam. 100 %
cycle.
steam is achievable, but 45-90 % is more typical for laboratory
7.1.3 In Crack-on Approach 1, the catalyst is subjected to
simulations.
severe hydrothermal deactivation after each cracking and
7.2.5.5 Repeat steps 7.2.3.4 through 7.2.5.4 for the number
regenerationcycle.Bythismethod,significantdeactivationhas
of desired cycles.
taken place by the time the metals addition is complete.
7.2.6 At the conclusion of the final deactivation step, cool
7.2 Procedure:
the furnace using the forced air circulation system.
7.2.1 Preparation of the Catalyst—Optionally screen the
7.2.7 Remove the catalyst.
catalyst to remove coarse contaminants and fine particles that
7.2.8 Analyze the deactivated catalyst.
would be lost during fluidization.
7.3 Variations:
7.2.2 Prepare the Feed:
7.3.1 The temperature of cracking and deactivation, as well
7.2.2.1 Weigh out and transfer the appropriate amount of
as the partial pressure of steam, are variables that can be
LGO into the feed vessel. The minimum amount of LGO will
customized as needed.
equal the number of cracking cycles times the amount fed per
7.3.2 Heavier feeds can be used in Approach 1 than the
cycle.
LGO cited here. Heavier, resid-containing oils would require
7.2.2.2 Individually add the organic metal compounds. The
heating of the pump and delivery lines.
massofeachmetaladdedshallbecalculatedtogivethedesired
7.3.3 When applying a high metal content inApproach 1, it
metalloadingonthecatalyst.Ifusingthistechniquetoperform
isadvisabletoaddcatalystinstages.Inthisvariation,aportion
an E-cat simulation, the metal target may have to be substan-
of the catalyst charge will have a relatively low metal content,
tially reduced by 25-50 % of t
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