ASTM D7206/D7206M-19

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of the standard as published by ASTM is to be considered the official document.
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Designation: D7206/D7206M − 06 (Reapproved 2013) D7206/D7206M − 19
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
1.1 This guide covers the deactivation of fluid catalytic cracking (FCC) catalyst in the laboratory as a precursor to small scale
performance testing. testing such as catalyst activities (Test Method D3907) or activities plus selectivities (Test Methods D5154
and D7964). 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. Catalyst deactivation by hydrothermal treatment
only is addressed in Guide D4463/D4463M.
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) 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 mayare not benecessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other. Combiningother, and values from the two systems may result in non-conformance with the
standard.shall not be combined.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
This guide is under the jurisdiction of ASTM Committee D32 on Catalysts and is the direct responsibility of Subcommittee D32.04 on Catalytic Properties.
Current edition approved March 1, 2013April 1, 2019. Published March 2013April 2019. Originally approved in 2006. Last previous edition approved in 20122013 as
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D7206/D7206M–06(2012)D7206/D7206M–06(2013) e1. DOI: 10.1520/D7206_D7206M-06R13E01.10.1520/D7206_D7206M-19.
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/D7206M − 19
2. Referenced Documents
2.1 ASTM Standards:
D3907 Test Method for Testing Fluid Catalytic Cracking (FCC) Catalysts by Microactivity Test
D4463/D4463M Guide for Metals Free Steam Deactivation of Fresh Fluid Cracking Catalysts
D5154 Test Method for Determining Activity and Selectivity of Fluid Catalytic Cracking (FCC) Catalysts by Microactivity Test
D7964 Test Method for Determining Activity of Fluid Catalytic Cracking (FCC) Catalysts in a Fluidized Bed
3. Terminology
3.1 Definitions:
3.1.1 crack-on—technique of depositing metals onto a catalyst through cracking of an FCC feed with enhanced metal content
in a fluidized catalyst bed that is at cracking temperature.
3.2 Acronyms:
3.2.1 E-cat—equilibrium catalyst from commercial FCCU.
3.2.2 FCC—fluid catalytic cracking.
3.2.3 FCCU—fluid catalytic cracking unit.
3.2.4 LGO—light gas oil, fluid at 40°C,40 °C, initial boiling point < 200°C,<200 °C, sulfur content < 1<1 mass percent.
3.2.5 VGO—vacuum gas oil, fluid at 70°C,70 °C, initial boiling point > 250°C,>250 °C, sulfur content of 2 to 3 mass percent.
4. Significance and Use
4.1 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.
5. Reagents
5.1 Feed, VGO.
5.2 Feed, LGO.
5.3 Hydrogen (H ), 42.8 % in nitrogen balance.
5.4 Nickel naphthenate or nickel octoate solution.
5.5 Nitrogen (N ).
5.6 Oxygen (O ), 40 % in nitrogen balance.
5.7 Vanadium naphthenate solution.
5.8 Cyclohexane.
5.9 n-pentane.
5.10 n-hexane.
5.11 Water, demineralized.
6. Hazards
6.1 The operations described in this guide involve handling heated objects, fragile glassware, and toxic organic nickel and
vanadium compounds.
6.2 All work with organic metals precursor solutions and other organic solvents should be completed in suitable vented fume
hood.
6.3 Appropriate personal protection equipment, including chemical goggles, laboratory smock, and disposable gloves should be
worn.
6.4 Waste organic metal solutions and organic solvents shall be disposed of properly in suitable waste containers and according
to regulations.
6.5 Vented furnaces and hoods should be regularly monitored for proper ventilation before using.
6.6 Evaporating dishes should be checked for cracks before use.
6.7 The muffle furnace used for the post-impregnation thermal treatment of the sample shall be appropriately and adequately
ventilated. Catalyst load sizes should be selected to avoid overwhelming the ventilation capacity of the furnace and allowing fumes
to escape into the laboratory.
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volume information, refer to the standard’s Document Summary page on the ASTM website.
D7206/D7206M − 19
6.8 To avoid the potential hazard of explosion in the muffle furnace, impregnated samples shall be completely dry of pentane
prior to beginning the thermal post-treatment.
6.9 Material safety data sheets (MSDS) for all materials used in the deactivation should be read and understood by operators
and should be kept continually available in the laboratory for review.
7. CPS Method
7.1 Summary of Practice—A fresh FCC catalyst is impregnated with nickel, or vanadium, or both. Nickel and vanadium levels
are controlled by a predetermined concentration for the sample. The catalyst is wetted with a mixture of pentane and nickel, nickel
naphthenate, or vanadium naphthenate, or solutions of both and then mixed to dryness. After drying, the sample is thermally treated
to remove residual naphthenates. The sample is then ready for hydrothermal treatment of analysis as desired.
7.2 Procedure:
7.2.1 Catalyst Pre-treatment Before Impregnation—For a muffle furnace pre-treatment (standard), place the sample in a dish
using a shallow bed ( ⁄2 in. maximum). Calcine the sample for 1 h at 204°C [400°F],204 °C [400 °F], then 3 h at 593°C
[1100°F].593 °C [1100 °F]. The sample is then removed and allowed to cool to room temperature. Catalyst should be returned to
a sealed container as soon as it is cool.
7.2.2 Steam Deactivation Pre-treatment—Typical conditions included hydrothermal treatment for 2 h at 816°C [1500°F],816 °C
[1500 °F], 100 % steam, and 0 psi. The catalyst is charged to a pipe reactor, fluidized in air, and then lowered over a 3-h3 h period
into a 816°C [1500°F]816 °C [1500 °F] sand bath furnace. Air flow is switched off and steam introduced for 2 h. The reactor is
then removed from the furnace and allowed to cool to room temperature under a nitrogen purge.
7.2.3 Preparation of Nickel and Vanadium Mixture—The desired nickel/vanadium levels are calculated for the quantity of
sample to be impregnated. The mass of nickel or vanadium naphthenate used to obtain the desired levels on the catalyst sample
are determined as follows:
N 5 T/S 3W (1)
where:
N = naphthenate (nickel or vanadium mass used to obtain the desired metal level on the catalyst),
T = target level (the desired mass percent of nickel or vanadium, or both, to be loaded on the catalyst),
S = metal solution (the known mass percent of nickel or vanadium in the naphthenate solution), and
W = mass of catalyst sample to be impregnated.
7.2.4 Impregnation:
7.2.4.1 Catalyst is poured into an evaporating dish. The dish shall be large enough to allow for a catalyst bed height of ⁄2 in.
7.2.4.2 Slowly pour the dissolved metals solution into the dish with catalyst while mixing at the same time. Wash the residual
naphthenate from the glass beaker with pentane and add the wash to the catalyst.
7.2.4.3 Stir the sample with a spoonula until it is completely dry. The appearance of very small lumps in the catalyst after drying
is normal. Large lumps indicate improper drying and shall be avoided. This can be done by adding enough pentane to moisten the
catalyst then repeating the stirring process. High levels of vanadium naphthenate will cause the sample to appear gummy and is
normal.
7.2.4.4 High Levels of Vanadium Naphthenate—When an impregnation calls for more than 5000 ppm vanadium, the
impregnation should be done in two steps. Otherwise, the volume of naphthenate will overwhelm the volume of catalyst used,
affecting the accuracy in reaching the target level. If over 5000 ppm vanadium is required, divide the required volume of vanadium
naphthenate in half, impregnate, post-treat, and impregnate again by adding the second half followed by a second post-treat. If
nickel is also requested, this should be divided and added to the catalyst along with the vanadium.
7.2.4.5 Antimony Addition—If antimony is requested, triphenylantimony is added to the catalyst after the nickel and vanadium
have been added and the post treatment has been completed. The impregnation procedure is the same as the nickel and vanadium
impregnation except that cyclohexane is used instead of pentane. Antimony will not dissolve in pentane.
7.2.5 Catalyst Post-treatment After Impregnation—After the impregnated sample has dried, it is placed in a vented muffle
furnace and heat treated to remove the naphthenates and coke formed. The dishes are placed in the furnace at room temperature
and the temperature is raised to 204°C [400°F]204 °C [400 °F] and held at temperature for 1 h. The sample is then calcined at
593°C [1100°F]593 °C [1100 °F] for 3 h before being removed and allowed to cool to room temperature.
7.2.6 Steam Deactivation—Several methods exist, each requiring specific conditions. An example of such a method is shown
in Table 1.
8. Crack-on Approach 1: Alternating Cracking and Deactivation Cycles
8.1 Summary of Practice:
8.1.1 The crack-on units consist of a fluid bed reactor with a fritted gas distributor on the bottom. Nitrogen, air, steam, and other
specialty gasses can be fed through the bottom. Oil can be delivered either from the top or bottom of the reactor depending on the
method. Temperature is controlled by a three zone electric furnace. A disengaging section on the top of the reactor prevents catalyst
loss during operation.
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TABLE 1 Standard CPS Procedure
NOTE 1—This scheme is considered standard and represents the case in
which the treatment ends in a state of reduction. A similar scheme in
which the cycles end in oxidation can also be configured.
Catalyst pre-treatment 1 h at 204°C [400°F] followed by 3 h at 593°C [1100°F]
Impregnation 2000 ppm nickel and 3000 ppm vanadium
Post-treatment 1 h at 204°C [400°F] followed by 3 h at 593°C [1100°F]
Steam deactivation 788°C [1450°F], 50% steam, 0 psig, 20 h (30 cycles)
Cycles consist of: 10 min, 50% mass percent N
10 min, 50% mass percent 4000 ppm SO in air
10 min, 50 mass percent N
10 min, 50 mass percent propylene-N mixture
(5% propylene in N )
TABLE 1 Standard CPS Procedure
NOTE 1—This scheme is considered standard and represents the case in
which the treatment ends in a state of reduction. A similar scheme in
which the cycles end in oxidation can also be configured.
Catalyst pre-treatment 1 h at 204 °C [400 °F] followed by 3 h at 593 °C [1100 °F]
Impregnation 2000 ppm nickel and 3000 ppm vanadium
Post-treatment 1 h at 204 °C [400 °F] followed by 3 h at 593 °C [1100 °F]
Steam deactivation 788 °C [1450 °F], 50 % steam, 0 psig, 20 h (30 cycles)
Cycles consist of: 10 min, 50 % mass percent N
10 min, 50 % mass percent 4000 ppm SO in air
10 min, 50 mass percent N
10 min, 50 mass percent propylene-N mixture
(5 % propylene in N )
8.1.2 The crack-on method involves depositing metals on the catalyst at cracking temperature using a fe
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