1、Designation:D446396 (Reapproved 2006) Designation: D4463/D4463M 96(Reapproved 2012)1Standard Guide forMetals Free Steam Deactivation of Fresh Fluid CrackingCatalysts1This standard is issued under the fixed designation D4463/D4463M; the number immediately following the designation indicates theyear o
2、f original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTEUpdated units statement and made a combined standard editorially
3、 in April 2012.1. Scope1.1 This guide covers the deactivation of fresh fluid catalytic cracking (FCC) catalyst by hydrothermal treatment prior to thedetermination of the catalytic cracking activity in the microactivity test (MAT).1.2 The hydrothermal treatment of fresh FCC catalyst, prior to the MAT
4、, is important because the catalytic activity of thecatalyst in its fresh state is an inadequate measure of its true commercial performance. During operation in a commercial crackingunit, the catalyst is deactivated by thermal, hydrothermal and chemical degradation. Therefore, to maintain catalytic
5、activity, freshcatalyst is added (semi) continuously to the cracking unit, to replace catalyst lost through the stack or by withdrawal, or both. Understeady state conditions, the catalyst inventory of the unit is called equilibrium catalyst. This catalyst has an activity levelsubstantially below tha
6、t of fresh catalyst. Therefore, artificially deactivating a fresh catalyst prior to determination of its crackingactivity should provide more meaningful catalyst performance data.1.3 Due to the large variations in properties among fresh FCC catalyst types as well as between commercial cracking unitd
7、esigns or operating conditions, or both, no single set of steam deactivation conditions is adequate to artificially simulate theequilibrium catalyst for all purposes.1.3.1 In addition, there are many other factors that will influence the properties and performance of the equilibrium catalyst.These i
8、nclude, but are not limited to: deposition of heavy metals such as Ni, V, Cu; deposition of light metals such as Na;contamination from attrited refractory linings of vessel walls. Furthermore, commercially derived equilibrium catalyst representsa distribution of catalysts of different ages (from fre
9、sh to 300 days). Despite these apparent problems, it is possible to obtainreasonably close agreement between the performances of steam deactivated and equilibrium catalysts. It is also recognized that itis possible to steam deactivate a catalyst so that its properties and performance poorly represen
10、t the equilibrium. It is thereforerecommended that when assessing the performance of different catalyst types, a common steaming condition be used. Catalystdeactivation by metals deposition is not addressed in this guide.1.4 This guide offers two approaches to steam deactivate fresh catalysts. The f
11、irst part provides specific sets of conditions (time,temperature and steam pressure) that can be used as general pre-treatments prior to comparison of fresh FCC catalyst MATactivities (Test Method D3907) or activities plus selectivities (Test Method D5154).1.4.1 The second part provides guidance on
12、how to pretreat catalysts to simulate their deactivation in a specific FCCU andsuggests catalyst properties which can be used to judge adequacy of the simulation. This technique is especially useful whenexamining how different types of catalyst may perform in a specific FCCU, provided no other chang
13、es (catalyst addition rate,regenerator temperature, contaminant metals levels, etc.) occur. This approach covers catalyst physical properties that can be usedas monitors to indicate the closeness to equilibrium catalyst properties.1.5The values stated in SI units are to be regarded as standard. The
14、values given in parentheses are for information only.1.5 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in eachsystem may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values
15、 from thetwo systems may result in non-conformance with the standard.1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibilityof the user of this standard to establish appropriate safety and health practices and determine the
16、applicability of regulatorylimitations prior to use.1This 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 Oct.April 1, 2006.2012. Published November 2006.July 2012. Originally
17、approved in 1985. Last previous edition approved in 20012006 asD446396(20016). DOI: 10.1520/D4463_D4463M-96R12E061.1This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Becauseit may n
18、ot be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current versionof the standard as published by ASTM is to be considered the official document.Copyright ASTM International, 100 Barr Harbor
19、Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.2. Referenced Documents2.1 ASTM Standards:2D3663 Test Method for Surface Area of Catalysts and Catalyst CarriersD3907 Test Method for Testing Fluid Catalytic Cracking (FCC) Catalysts by Microactivity TestD3942 Test Method for Determ
20、ination of the Unit Cell Dimension of a Faujasite-Type ZeoliteD4365 Test Method for Determining Micropore Volume and Zeolite Area of a CatalystD5154 Test Method for DeterminingActivity and Selectivity of Fluid Catalytic Cracking (FCC) Catalysts by Microactivity TestE105 Practice for Probability Samp
21、ling of MaterialsE177 Practice for Use of the Terms Precision and Bias in ASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method3. Summary of Guide3.1 A sample of fresh fluid cracking catal
22、yst is placed in a reactor, either fixed bed or preferably fluid bed, and is contacted withsteam at elevated temperature. This treatment causes partial deactivation of the catalyst.NOTE 1In a fixed bed reactor, material containing sulfates, chlorides, etc. can result in significant additional chemic
23、al deactivation.3.2 The catalyst is withdrawn from the reactor and may be subjected to an activity or activity plus selectivity determination,by using the microactivity test (Test Methods D3907 or D5154).4. Significance and Use4.1 In general, steam treatment of FCC catalyst can be used either to com
24、pare a series of cracking catalysts at a simulatedequilibrium condition or conditions, or to simulate the equilibrium condition of a specific cracking unit and a specific catalyst. Thisguide gives an example for the first purpose and an approach for the latter purpose.5. Apparatus5.1 Fixed bed or fl
25、uid bed steaming reactors can be used for the hydrothermal treatment of FCC catalyst.5.2 In the steaming reactor, temperatures of the catalyst can be maintained at selected constant mean levels between 700C(1292F)1292F and 850C (1562F)1562F 6 2C (6 3.6F)6 3.6F during the steam treatment.5.3 Temperat
26、ure control during steam treatment is critical, as temperature variations of 62C (63.6F)63.6F can lead to 61wt. % conversion changes or more, especially at higher temperatures.5.4 In fixed bed steaming, the temperature gradient through the catalyst bed should be kept as small as possible and should
27、notexceed 4C (7.2F).7.2F. In fluid bed steaming the bed temperature must be homogeneous.5.5 Heating and cooling of the catalyst must be performed in the reactor under a flow of dry nitrogen.5.6 Precautions must be taken to achieve uniform contact of the steam with the bed.6. Sampling6.1 A suitable s
28、ampling procedure is needed. Practice E105 is appropriate.7. Sample Preparation7.1 No sample preparation is necessary if the catalyst is heated slowly during preheating (non-shock steaming).7.2 If the sample is introduced directly into a preheated steaming reactor, (shock-steaming) it is desirable t
29、o predry the samplefor about one hour at about 550C (1022F)1022F to prevent excessive catalyst loss.8. Procedure8.1 Procedure for fluid bed and fixed bed steam treatment (non-shock steaming):8.1.1 With the reactor heated to 300C (572F)572F or lower, load the reactor with catalyst.8.1.2 Start nitroge
30、n flow to the reactor at a flow velocity of 3 cm/s (0.1 ft/s).0.1 ft/s.8.1.3 Heat the reactor at the maximum rate until a temperature of 600C (1112F)1112F is reached.8.1.4 Keep the temperature constant at 600C (1112F)1112F for 30 min in order to remove volatile material from thecatalyst.8.1.5 Heat t
31、he reactor at the maximum rate until the desired steaming temperature is reached; for example, at 760, 788 or 800C(1400,1400, 1450 or 1472F)1472F 6 2C (6 3.6F).6 3.6F.8.1.6 Stop the nitrogen flow and start a flow of undiluted steam at atmospheric pressure and at constant temperature (760, of760, 788
32、 or 800C). 800C 1400, 1450 or 1472F. Continue this steam flow for 5 hours. For fixed bed operation, keep the steam2For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at serviceastm.org. For Annual Book of ASTM Standardsvolume information, refer to t
33、he standards Document Summary page on the ASTM website.D4463/D4463M 96 (2012)12flow velocity at 5 6 1 cm/s (0.160.16 6 0.03 ft/s)ft/s at the desired deactivation temperature. For fluid bed operation, keep thesteam velocity at 3 6 1 cm/s (0.100.10 6 0.03 ft/s).ft/s.8.1.7 After 5 h, stop the steam flo
34、w and start nitrogen flowing at 3 cm/s (0.10 ft/s)0.10 ft/s through the reactor.8.1.8 Cool down the reactor to less than 300C (572F).572F. The rate of cooling is not critical.8.1.9 Remove the catalyst from the reactor and store in a sealed bottle.8.2 Variations in this procedure in which predried ca
35、talyst is added to a steaming reactor preheated to the desired steamingtemperature (shock steaming) are also permissible provided a consistent procedure is used.8.3 Testing of Steamed CatalystThe steamed catalyst may be tested for gas oil cracking activity or activity plus selectivity,using Test Met
36、hods D3907 or D5154, respectively.9. Precision and Bias39.1 Test ProgramAn interlaboratory study was conducted in which the wt % MAT Conversion was measured in two testmaterials steamed at three temperatures each in fixed or fluid bed steaming reactors in ten separate laboratories. Multiple samplepo
37、rtions were steamed only by some laboratories, and not all temperatures were used by all the laboratories. Practice E691 wasfollowed to the extent practicable for the data set. Analysis details are in the research report.9.2 PrecisionPairs of test results obtained by a procedure similar to that desc
38、ribed in the study are expected to differ in relativevalue by less than 2.772*S, where 2.772*S is the 95 % probability interval limit on the difference between two test results, andS is the appropriate estimate of relative standard deviation. Definitions and usage are given in Terminology E456 and P
39、racticeE177, respectively.Mean Within-LabRelative StandardDeviation in Wt. %MAT ConversionMean Within-LabRelative StandardDeviation in Wt. %MAT ConversionS=2.6%S=2.6% S=2.6%Mean Between-LabRelative StandardDeviation in Wt. %MAT ConversionMean Between-LabRelative StandardDeviation in Wt. %MAT Convers
40、ionS=4.8%S=4.8% S=4.8%The within-lab repeatability is of the same order as that found for the wt. % MAT conversion itself.3Supporting data have been filed at ASTM International Headquarters and may be obtained by requesting Research Report RR:D32-1012.D4463/D4463M 96 (2012)139.3 BiasThis procedure i
41、s without known bias, since there is by definition no absolute standard for comparison.10. Approach to Simulate a Certain Equilibrium Catalyst10.1 It is frequently desirable to find steaming conditions which give as close a match as possible to the properties of anequilibrium catalyst from a particu
42、lar FCC unit. These conditions can then be used with other catalysts to be evaluated for thatunit with some assurance that the steaming conditions are appropriate to simulate the severity of that particular catalyst additionrate and the regenerator severity. Due to differences in hydrothermal stabil
43、ity of various zeolite and matrix components currentlyin use in FCC catalysts, a perfect match cannot be obtained with all catalysts under the same steaming conditions.10.2 Critical steamed catalyst properties to be matched to the equilibrium catalyst include MAT conversion (activity) andselectivity
44、 to products such as coke, hydrogen and C1to C3hydrocarbons which are sensitive to the relative activities of the zeoliteand matrix components of contemporary cracking catalysts.4Also the ratio of isobutane/(C3olefins + C4olefins) can be used asan indicator for the ratio of zeolite cracking/matrix c
45、racking. Another critical parameter is the zeolite unit cell size which is, formany catalysts, related to gasoline octane quality. Physical measurements which have been found to be particularly useful inevaluating the match between steamed and equilibrium catalysts are total, matrix (mesopore) and (
46、by difference) zeolite(micropore) surface areas as defined by Test Methods D3663 and D4365 and zeolite unit cell size of the zeolite from Test MethodD3942.10.3 A major problem in steaming fresh catalysts to match equilibrium catalyst is that the zeolite and matrix componentsdeactivate at different r
47、ates relative to each other under accelerated hydrothermal conditions than they do at the lower temperaturesand steam partial pressures in the FCC unit regenerator.5This rate difference is most pronounced with high matrix activity catalystshaving hydrothermally stable matrices and results in steamed
48、 catalysts having excessive matrix activity at the same overall activityas the equilibrium catalyst. Relatively higher matrix activity shows up as higher coke, hydrogen and light hydrocarbon yields inthe MAT relative to the equilibrium catalyst and as a higher matrix (mesopore) surface area. This pr
49、oblem can be alleviatedsomewhat by using longer steaming times at lower temperature, but cannot be eliminated by any practical experimental conditions.10.4 Steaming conditions which have proven to be useful and practical for simulating various FCC units are times of 4 to 6 hat temperatures from about 780C (1436F)1436F to 810C (1490F).1490F.Alternatively, longer times of 16 to 24 h at about25C (45F)45F lower temperatures may be used. Another technique to simulate equilibrium catalyst p
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