1、Designation: D4463/D4463M 96 (Reapproved 2013)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 of original adoption or, in the case o
2、f 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.1NOTEEditorially changed 1.3.1 and 2.1 in March 2013.1. Scope1.1 This guide covers the deactivation of fre
3、sh fluid cata-lytic cracking (FCC) catalyst by hydrothermal treatment priorto the determination of the catalytic cracking activity in themicroactivity test (MAT).1.2 The hydrothermal treatment of fresh FCC catalyst, priorto the MAT, is important because the catalytic activity of thecatalyst in its f
4、resh state is an inadequate measure of its truecommercial performance. During operation in a commercialcracking unit, the catalyst is deactivated by thermal, hydrother-mal and chemical degradation. Therefore, to maintain catalyticactivity, fresh catalyst is added (semi) continuously to thecracking u
5、nit, to replace catalyst lost through the stack or bywithdrawal, or both. Under steady state conditions, the catalystinventory of the unit is called equilibrium catalyst. Thiscatalyst has an activity level substantially below that of freshcatalyst. Therefore, artificially deactivating a fresh cataly
6、stprior to determination of its cracking activity should providemore meaningful catalyst performance data.1.3 Due to the large variations in properties among freshFCC catalyst types as well as between commercial crackingunit designs or operating conditions, or both, no single set ofsteam deactivatio
7、n conditions is adequate to artificially simu-late the equilibrium catalyst for all purposes.1.3.1 In addition, there are many other factors that willinfluence the properties and performance of the equilibriumcatalyst. These include, but are not limited to: deposition ofheavy metals such as Ni, V, C
8、u; deposition of light metals suchas Na; contamination from attrited refractory linings of vesselwalls. Furthermore, commercially derived equilibrium catalystrepresents a distribution of catalysts of different ages (fromfresh to 300 days). Despite these apparent problems, it ispossible to obtain rea
9、sonably close agreement between theperformances of steam deactivated and equilibrium catalysts. Itis also recognized that it is possible to steam deactivate acatalyst so that its properties and performance poorly representthe equilibrium. It is therefore recommended that when assess-ing the performa
10、nce of different catalyst types, a commonsteaming condition be used. Catalyst deactivation by metalsdeposition is not addressed in this guide, but is addressed inGuide D7206/D7206M.1.4 This guide offers two approaches to steam deactivatefresh catalysts. The first part provides specific sets of condi
11、-tions (time, temperature and steam pressure) that can be usedas general pre-treatments prior to comparison of fresh FCCcatalyst MAT activities (Test Method D3907) or activities plusselectivities (Test Method D5154).1.4.1 The second part provides guidance on how to pretreatcatalysts to simulate thei
12、r deactivation in a specific FCCU andsuggests catalyst properties which can be used to judgeadequacy of the simulation. This technique is especially usefulwhen examining how different types of catalyst may perform ina specific FCCU, provided no other changes (catalyst additionrate, regenerator tempe
13、rature, contaminant metals levels, etc.)occur. This approach covers catalyst physical properties thatcan be used as monitors to indicate the closeness to equilibriumcatalyst properties.1.5 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values s
14、tated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.6 This standard does not purport to address all of thesafety concerns, if any, associated with its u
15、se. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.1This guide is under the jurisdiction of ASTM Committee D32 on Catalysts andis the direct responsibility of Subcommit
16、tee D32.04 on Catalytic Properties.Current edition approved March 1, 2013. Published March 2013. Originallyapproved in 1985. Last previous edition approved in 2012 as D4463/D4463M96(2012)e1. DOI: 10.1520/D4463_D4463M-96R13E01.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Con
17、shohocken, PA 19428-2959. United States12. Referenced Documents2.1 ASTM Standards:2D3663 Test Method for Surface Area of Catalysts andCatalyst CarriersD3907 Test Method for Testing Fluid Catalytic Cracking(FCC) Catalysts by Microactivity TestD3942 Test Method for Determination of the Unit CellDimens
18、ion of a Faujasite-Type ZeoliteD4365 Test Method for Determining Micropore Volume andZeolite Area of a CatalystD5154 Test Method for DeterminingActivity and Selectivityof Fluid Catalytic Cracking (FCC) Catalysts by Microac-tivity TestD7206/D7206M Guide for Cyclic Deactivation of FluidCatalytic Crack
19、ing (FCC) Catalysts with MetalsE105 Practice for Probability Sampling of MaterialsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Meth
20、od3. Summary of Guide3.1 A sample of fresh fluid cracking catalyst is placed in areactor, either fixed bed or preferably fluid bed, and iscontacted with steam at elevated temperature. This treatmentcauses partial deactivation of the catalyst.NOTE 1In a fixed bed reactor, material containing sulfates
21、, chlorides,etc. can result in significant additional chemical deactivation.3.2 The catalyst is withdrawn from the reactor and may besubjected to an activity or activity plus selectivitydetermination, by using the microactivity test (Test MethodsD3907 or D5154).4. Significance and Use4.1 In general,
22、 steam treatment of FCC catalyst can be usedeither to compare a series of cracking catalysts at a simulatedequilibrium condition or conditions, or to simulate the equilib-rium condition of a specific cracking unit and a specificcatalyst. This guide gives an example for the first purpose andan approa
23、ch for the latter purpose.5. Apparatus5.1 Fixed bed or fluid bed steaming reactors can be used forthe hydrothermal treatment of FCC catalyst.5.2 In the steaming reactor, temperatures of the catalyst canbe maintained at selected constant mean levels between 700C1292F and 850C 1562F 62C 63.6F during t
24、hesteam treatment.5.3 Temperature control during steam treatment is critical,as temperature variations of 62C 63.6F can lead to 61wt. % conversion changes or more, especially at higher tem-peratures.5.4 In fixed bed steaming, the temperature gradient throughthe catalyst bed should be kept as small a
25、s possible and shouldnot exceed 4C 7.2F. In fluid bed steaming the bed tempera-ture must be homogeneous.5.5 Heating and cooling of the catalyst must be performedin the reactor under a flow of dry nitrogen.5.6 Precautions must be taken to achieve uniform contact ofthe steam with the bed.6. Sampling6.
26、1 A suitable sampling procedure is needed. Practice E105is appropriate.7. Sample Preparation7.1 No sample preparation is necessary if the catalyst isheated slowly during preheating (non-shock steaming).7.2 If the sample is introduced directly into a preheatedsteaming reactor, (shock-steaming) it is
27、desirable to predry thesample for about one hour at about 550C 1022F to preventexcessive 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 or lower,load the reactor with catalyst.8.1.2 Start nitrogen flo
28、w to the reactor at a flow velocity of3 cm/s 0.1 ft/s.8.1.3 Heat the reactor at the maximum rate until a tempera-ture of 600C 1112F is reached.8.1.4 Keep the temperature constant at 600C 1112F for30 min in order to remove volatile material from the catalyst.8.1.5 Heat the reactor at the maximum rate
29、 until the desiredsteaming temperature is reached; for example, at 760, 788 or800C 1400, 1450 or 1472F 62C 63.6F.8.1.6 Stop the nitrogen flow and start a flow of undilutedsteam at atmospheric pressure and at constant temperature of760, 788 or 800C 1400, 1450 or 1472F. Continue thissteam flow for 5 h
30、ours. For fixed bed operation, keep the steamflow velocity at 5 6 1 cm/s 0.16 6 0.03 ft/s at the desireddeactivation temperature. For fluid bed operation, keep thesteam velocity at 3 6 1 cm/s 0.10 6 0.03 ft/s.8.1.7 After 5 h, stop the steam flow and start nitrogenflowing at 3 cm/s 0.10 ft/s through
31、the reactor.8.1.8 Cool down the reactor to less than 300C 572F. Therate of cooling is not critical.8.1.9 Remove the catalyst from the reactor and store in asealed bottle.8.2 Variations in this procedure in which predried catalyst isadded to a steaming reactor preheated to the desired steamingtempera
32、ture (shock steaming) are also permissible provided aconsistent procedure is used.8.3 Testing of Steamed CatalystThe steamed catalyst maybe tested for gas oil cracking activity or activity plusselectivity, using Test Methods D3907 or D5154, respectively.2For referenced ASTM standards, visit the ASTM
33、 website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.D4463/D4463M 96 (2013)129. Precision and Bias39.1 Test ProgramAn interlaboratory study was conductedin whic
34、h the wt % MAT Conversion was measured in two testmaterials steamed at three temperatures each in fixed or fluidbed steaming reactors in ten separate laboratories. Multiplesample portions were steamed only by some laboratories, andnot all temperatures were used by all the laboratories. PracticeE691
35、was followed to the extent practicable for the data set.Analysis details are in the research report.9.2 PrecisionPairs of test results obtained by a proceduresimilar to that described in the study are expected to differ inrelative value by less than 2.772*S, where 2.772*S is the 95 %probability inte
36、rval limit on the difference between two testresults, and S is the appropriate estimate of relative standarddeviation. Definitions and usage are given in TerminologyE456 and Practice E177, respectively.Mean Within-LabRelative StandardDeviation in Wt. %MAT Conversion95 % RepeatabilityInterval (Within
37、Laboratory)S = 2.6 % 7.2 %Mean Between-LabRelative StandardDeviation in Wt. %MAT Conversion95 % ReproducibilityInterval (BetweenLaboratories)S=4.8% 13.3%The within-lab repeatability is of the same order as thatfound for the wt. % MAT conversion itself.9.3 BiasThis procedure is without known bias, si
38、nce thereis by definition no absolute standard for comparison.10. Approach to Simulate a Certain EquilibriumCatalyst10.1 It is frequently desirable to find steaming conditionswhich give as close a match as possible to the properties of anequilibrium catalyst from a particular FCC unit. These condi-t
39、ions can then be used with other catalysts to be evaluated forthat unit with some assurance that the steaming conditions areappropriate to simulate the severity of that particular catalystaddition rate and the regenerator severity. Due to differences inhydrothermal stability of various zeolite and m
40、atrix compo-nents currently in use in FCC catalysts, a perfect match cannotbe obtained with all catalysts under the same steaming condi-tions.10.2 Critical steamed catalyst properties to be matched tothe equilibrium catalyst include MAT conversion (activity) andselectivity to products such as coke,
41、hydrogen and C1to C3hydrocarbons which are sensitive to the relative activities ofthe zeolite and matrix components of contemporary crackingcatalysts.4Also the ratio of isobutane/(C3olefins + C4olefins)can be used as an indicator for the ratio of zeolite cracking/matrix cracking. Another critical pa
42、rameter is the zeolite unitcell size which is, for many catalysts, related to gasoline octanequality. Physical measurements which have been found to beparticularly useful in evaluating the match between steamedand equilibrium catalysts are total, matrix (mesopore) and (bydifference) zeolite (micropo
43、re) surface areas as defined by TestMethods D3663 and D4365 and zeolite unit cell size of thezeolite from Test Method D3942.10.3 A major problem in steaming fresh catalysts to matchequilibrium catalyst is that the zeolite and matrix componentsdeactivate at different rates relative to each other unde
44、raccelerated hydrothermal conditions than they do at the lowertemperatures and steam partial pressures in the FCC unitregenerator.5This rate difference is most pronounced with highmatrix activity catalysts having hydrothermally stable matricesand results in steamed catalysts having excessive matrixa
45、ctivity at the same overall activity as the equilibrium catalyst.Relatively higher matrix activity shows up as higher coke,hydrogen and light hydrocarbon yields in the MAT relative tothe equilibrium catalyst and as a higher matrix (mesopore)surface area. This problem can be alleviated somewhat byusi
46、ng longer steaming times at lower temperature, but cannotbe eliminated by any practical experimental conditions.10.4 Steaming conditions which have proven to be usefuland practical for simulating various FCC units are times of 4 to6 h at temperatures from about 780C 1436F to 810C1490F. Alternatively
47、, longer times of 16 to 24 h at about25C 45F lower temperatures may be used. Another tech-nique to simulate equilibrium catalyst properties is to mixportions of catalyst, each steamed under different conditions oftime, temperature and steam partial pressure, in order to bettermatch the presence of d
48、ifferent catalyst ages in an actualequilibrium catalyst.6Also mixtures of fresh and uniformlysteamed catalyst portions can simulate the selectivity proper-ties of equilibrium catalysts.711. Keywords11.1 catalytic activity; fresh fluid cracking catalyst; hydro-thermal treatment; microactivity test; s
49、team deactivation3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:D32-1012.4Campagna, R. J., Wick, J. P., Brady, M. E., and Fort, D. L., “ Fresh FCCCatalyst Tests Predict Performance,” Oil and Gas Journal, March 24, 1986, pp.8596.5Chester, Arthur W. and Stover, William A., “Steam Deactivation Kinetics ofZeolite Cracking Catalysts,” Ind. Eng. Chem. Prod. Res. Dev, Vol 16, No. 4, 1977,pp. 285290.6Keyworth, D. A., Turner, W. J., and Re
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