Table Of ContentHandbook of Spent
Hydroprocessing Catalysts
Second Edition
Dr. Meena Marafi
Petroleum Research Center
Kuwait Institute for Scientific Research
Safat, Kuwait
Dr. Antony Stanislaus
Petroleum Research Center
Kuwait Institute for Scientific Research
Safat, Kuwait
Dr. Edward Furimsky
IMAF Group
Ottawa, ON, Canada
Elsevier
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Preface
Thepetroleum refining strategymay requiresomereadjustmentsinlinewith the increasing
supply ofunconventionalcrude. The previouslyanticipated steadilyincreasing consumption
ofhydroprocessingcatalystsneedsto bereevaluated. Somerefineriesweremodifying
operationstoaccommodateincreasing volume ofheavycrude.Insomepartsoftheworld,
these trends had tobereconsidered once theproductionof unconventional crude from oil
shalesourcesreached commercial level.The contentofatmosphericdistillatesin unconven-
tional crude may approach 80%.The paraffinic natureof these distillatesrequires catalysts
with ahigh hydroisomerizationactivity. These requirementscan be met using new catalyst
formulations. Therefore,notonly thequantitybutalso the typeof hydroprocessingcatalysts
will change. Correspondingspent hydroprocessingcatalystsrequireadditional attention to
ensure safetyand environmentalcomplianceduring allhandling stages.
Insomepartsoftheworld, increased refining capacity toaccommodateheavyandextra
heavycrudes tooffseta steady decline inthe supplyof conventional crudewillbenecessary.
This willtranslateintoanincreased consumptionof catalyst and hydrogen unless moreactive
and stable catalystsare developed.Inaddition,advancesindevelopmentofnovelmoreeffi-
cienthydroprocessing reactorshave beennoted. Globally,a rathercomplex situationin the
hydroprocessing catalystmarketmaybeanticipated.This makesany predictionsof catalyst
consumption and generationofspentcatalystsuncertain.
Spentconventionalhydroprocessing catalystshave beenclassifiedas hazardous solids
because oftheirflammabilityas wellastheirability torelease toxicspeciesin theairand in
water. The hazardoussoliddesignationrequires thatspecialprocedures haveto beapplied
during allstages ofspent catalysthandling,includingremovalfrom reactor, temporary
storage, packaging, transportation, and disposalinlandfills.Itisthe responsibility ofthe
refiner thatalltheseactivitiesarecarried outinaccordancewith the relevant regulations. To
ensure environmental compliance,refineriescan establish partnershipwith companiesand/or
consortiaof companieswith expertiseinallaspectsof spent hydroprocessing catalysts.
Compared withspentconventionalcatalysts,the environmentaland safetyaspectsofspent
unconventional catalystsare lessunderstood. Because ofa higher reactivityofcoke onspent
catalysts,a higher flammability compared withconventionalcatalystsmaybe anticipated.
xi
Preface
Other characteristics ofspent unconventional catalystsare unknown. Inthisregard,anaddi-
tional researchisrequired tofill thegap beforenecessarylawsand actscan beimplemented
byregulatory authorities.
Today,a large portionofthe spent hydroprocessingcatalystsisrecycledback tothe operation
afterbeing regenerated.Regenerationiscarriedout bycompanieswhoreceivednecessary
certifications from regulatoryauthorities.A rejuvenationprocess has been developed inan
effort torecycle these catalysts also,which aredeactivatedbymetals.Forsuchcatalysts,
regenerationas theonly step maynotensure desirable recovery ofcatalystactivity. If
regenerated/rejuvenatedcatalystscannot beused inthe originalreactor,they can becascaded
to either less ormore severe operation.Recently,significant advancements have been made in
reprocessingspentcatalysts.In fact,performance ofthe reprocessedcatalystsexceededthat
of thecorresponding freshcatalysts.Apparently, reprocessinggivesnew dimension torecy-
clingof spenthydroprocessingcatalysts.
A number ofnonhydroprocessing catalyticapplications for spent catalystswere identified.
Thus, ahighsulfur affinityoftransitionmetalspresentinspenthydroprocessing catalysts
suggeststhatafterdecokingspent catalysts may beused assorbents forgasclean-up.
Attemptsto usespentcatalystsfor watertreatmenthave also been noted.Construction
materials (e.g., cementandbricks)as wellasspecialtiessuch asabrasives,alloys,ceramic,
andsuch representadditional outletsfor spent hydroprocessing catalysts.
Spent conventional hydroprocessingcatalystshave beenattractingattention aspotential
sources ofmetalssuch asMo,W, Co, Ni, and V. Inmost cases,the content ofthese metalsis
greaterthan thatinoresused for theirproduction. The methodsused for themetals
reclamationfrom spentcatalystsreached acommercial stage. Infact,aftersomemodifica-
tions, theestablishedhydrometallurgical methodsused for metalsproductionfrom various
ores and industrialby-products can bealso appliedtospentcatalysts. Inrecentyears,theef-
fortstoimprove existingand/or todevelop novelmetalrecovery methods tosuitspent hydro-
processing catalystshave beennoted. Itshouldbe emphasizedthattheviabilityofmetals
recovery from spent catalysts isinfluencedbydemandand pricesthathave been exhibiting
significantfluctuations.
Platinumgroupmetals(e.g.,Pt, Pd, Ru, and Rh) areusualactive metalspresentinunconven-
tional catalysts.Becauseof theirvalue,metalreclamation from correspondingspentcatalysts
appears tobethe onlyoption.In thisregard, metalrecoverycanbenefitfrom decades of
experiencein metalsreclamation fromnonhydroprocessing types ofcatalysts(e.g.,
automotiveandreformingcatalysts). Inother words,the sameand/orslightlymodifiedmeth-
odologycan beappliedfor the metalrecovery fromspentunconventionalhydroprocessing
catalysts.
Continuous interest inallaspectsofspent hydroprocessing catalystshasbeen indicatedby
vigorousresearch activities sincethe firsteditionofthisHandbook. Thus,some250 new
xii
Preface
references were identified and incorporated intothe secondedition.The petroleum refining
industryhas beenmakingeffortstoimprove theefficiency ofoperationinlinewithmore
stringentenvironmentalregulations.Theavailabilityofanunconventional crude required
modificationofrefiningschemes includingthe catalysts,which intheircomposition differ
from thatofconventionalcatalysts.Accordingly, Chapters1, 2and3 were modifiedin line
with the mostrecent informationavailableinliterature. Because ofdirect impactonspent
catalyst regenerationandrejuvenation, Chapter4,dealingwith catalyst deactivation, was
expandedto include fournew sections.The most recentrelevant informationonregeneration
and rejuvenationwasincorporatedintoChapters5 and 6,respectively.The cascadingof
spent, regeneratedand rejuvenatedhydroprocessing catalystsintodifferentoperations is
highlighted inChapter7.Thepreparation ofnew catalystsbyreprocessing ofspentcatalysts
isdescribed inChapter8.
Thepotentialof spenthydroprocessingcatalystsinnoncatalyticapplications has notyetbeen
fullyrealized. Inthisregard,new Chapters 9 and 10comprisematerialfrom the firstedition
together withrecent information. Afterdecokinga numberofenvironmentally relatedoptions
(Chapter9)have beenidentified. Also, the suitabilityof spent catalystsformanufacturing
varioususeful materials (Chapter 10)hasbeen highlighted. Continuous effortshave been
made toimprove the efficiency ofmetalsreclamation from spent hydroprocessing catalysts.
This isreflected byanupdated Chapter11.
Theobjectiveof Chapter12isto highlight therole ofunconventionalcatalystsinhydro-
processing.This includes theformer chapteronspentdewaxingcatalysts,whichinessence
are unconventionalcatalystsconsistingofplatinumgroup metals.Thisisthefirsttime that
the characteristicsaswell asenvironmental and safetyaspectsofspentunconventional
catalystsare discussed.
Chapter 13isdevotedtoenvironmentaland safety aspectsofconventional spent catalysts
includingregulatoryissues.Inaddition,the emissionswithin regulatorylevelsmustbe main-
tained duringallstagesofspentcatalystgeneration and subsequent utilization. Therefore,
sections onenvironment and safetywere added toChapters 3,5,and6 regardinghydro-
processing technology,regeneration, and rejuvenation,respectively. The priceofmetals
which arepart ofhydroprocessing catalysts dictatesthe economic viability ofspent catalyst
utilization.In thisregard, thepricefluctuationonthecommoditymarkets hasbeen notedas
indicatedin Chapter14. Thisadds touncertaintyindefiningfutureperspectives (Chapter15)
inallaspectsofspenthydroprocessing catalysts.
xiii
List of Acronyms
API American Petroleum Institute
ARDS Atmospheric residue desulfurization
AC Activated carbon
CAC Clean air act
CCR Conradson carbon residue
CERCLA Comprehensive Environmental Response Compensation and Liability
Act
CUS Coordinatively unsaturated site
CWA Clean Water Act
DAO Deasphalted oil
DOC Dynamic oxygen chemisorption
DTA Differential thermal analysis
EPA Environmental Protection Agency
EXAFS Extended X-ray absorption fine spectroscopy
FCC Fluid catalytic cracking
FTIR Fourier transfer infrared
FTS FischereTropsch synthesis
HDAr Hydrodearomatization
HDAs Hydrodeasphalting
HCR Hydrocracking
HDM Hydrodemetallization
HDN Hydrodenitrogenation
HDNi Hydrodenickelization
HDO Hydrodeoxygenation
HDS Hydrodesulfurization
HDV Hydrodevanadization
HGO Heavy gas oil
HIS Hydroisomerization
HSWA Hazardous Solid Waste Amendment
xv
List of Acronyms
HWTF Hazardous waste trust fund
HYD Hydrogenation
KISR Kuwait Institute for Scientific Research
LM LangmuireHinshelwood
MSDS Material safety data sheet
NAAQS National Ambient Air Quality Standard
NESHAP National Emissions Standards for Hazardous Air Pollutants
NPDWS National Primary Drinking Water Standards
NSDWS National Secondary Drinking Water Standards
PAH Polyaromatic hydrocarbons
RCRA Resource Conservation & Recovery Act
RFCC Residue fluid catalytic cracking
SAPO Silica-alumina phosphate
SDWA Safety Drinking Water Act
SEM Scanning electron microscopy
SMCRA Surface Mining Control and Reclamation Act
STM Scanning tunnelling microscopy
TCLP Toxicity characteristics leaching procedure
TCM Total catalyst management
TEM Transition electron spectroscopy
TGA Thermal gravimetric analysis
THF Tetrahydrofuran
THFIS Tetrahydrofuran insolubles
TIS Toluene insolubles
TPD Temperature programmed desorption
TPO Temperature programmed oxidation
TPP Temperature programmed pyrolysis
TPR Temperature programmed reduction
TSCA Toxic Substance Control Act
TSDF Treatment storage and disposal facility
TDGA Transportation of Dangerous Goods Act
VGO Vacuum gas oil
XPS X-ray photoelectron spectroscopy
XRD X-ray diffraction spectroscopy
xvi
CHAPTER 1
Introduction
Petroleum refining strategies have been influenced by the gradual change in the quality of
conventional crude oil. Not long ago, this change involved a declining supply of light
crudes offset by an increasing volume of heavy crudes. In recent years, the world crude
market has been influenced by the availability of unconventional crude oil occurring in
low-permeability sedimentary formations, so-called “light tight oil.” These changes have
been evident particularly in the United States, while other parts of the world are following.
In addition, biomass-derived feeds have been identified as a source of fuel although their
impact on the slate of commercial fuel products is anticipated to be minor. Petroleum
refineries must respond to these developments with a readjustment of refining strategies.
This includes modifications to hydroprocessing (HPR) operations, i.e., new types of
catalysts and catalytic reactors.
In a world of change, the petroleum refiner has a choice from among several types of
commercial processes for the HPR of conventional and unconventional petroleum feeds.
The HPR feeds derived from conventional crude via atmospheric distillation include
straight-run distillates and atmospheric residue (AR). The latter can be subjected to
additional distillation under vacuum to obtainvacuum gas oil (VGO) and vacuum residue
(VR). The content of metals and asphaltenes in AR and VR can be decreased substantially
by solvent deasphalting to obtain deasphalted oil (DAO). During HPR, it is more difficult
to upgrade VR than AR, whereas fewer problems have been experienced with catalytic
upgrading of VGO and DAO. Decades of refinery experience have confirmed that the
atmospheric distillates can be upgraded without any difficulties. The difficulty and/or
severity of upgrading via HPR increases with increasing content of contaminants (e.g.,
metals, resins, asphaltenes, sulfur, and nitrogen) in the feed. The increase in severity
results in the increased consumption of hydrogen and catalyst.
The conversion of heavy and ultraheavy crude to distillates is necessary as the first step
during the production of liquid fuels. For this purpose, a number of commercial processes
are available [1,2]. They include hydrocracking (HCR) with hydrogen addition to the feed
and thermal conversion (coking) involving carbon rejection from the feed. The hydrogen
addition processes require the presence of an active catalyst. Compared with thermal
processes, HPR operations are more flexible, giving higher yields of liquid fractions.
However, the costs of high-pressure equipment, catalyst inventory, and H required for
2
HPR must be offset by increased yield and quality of the liquid products. In an extreme
HandbookofSpentHydroprocessingCatalysts.http://dx.doi.org/10.1016/B978-0-444-63881-6.00001-9
Copyright©2017ElsevierB.V.Allrightsreserved. 1
2 Chapter 1
case (e.g., extra-heavy feeds), carbon rejection is the route of choice compared with
hydrogen addition. However, some hydrogen addition processes (e.g., slurry bed HCR)
have been designed to handle heavy feeds containing as much as 700ppm of metals and
more than 20wt% of asphaltenes [3e7].
The composition of distillate feeds obtained from conventional crude via distillation may
differ from that of distillates with a similar boiling range produced using carbon-rejecting
processes. For the latter, the constituents of primary interest (e.g., S- and N-containing
compounds) are of a more refractory nature. Therefore, more severe HPR conditions are
required to achieve a desirable level of hydrodesulfurization and hydrodenitrogenation.
Also, these feeds have a higher content of Conradson carbon residueeforming precursors.
Therefore, a higher consumption of hydrogen and catalyst should be anticipated if those
trends continue.
The aforementioned trends may have to be readjusted because of the availability of an
unconventional crude such as light tight oil, which is now being produced commercially.
Light tight oil has a boiling range similar to that of light conventional crude (e.g., Brent
crude). This suggests that not only the volume but also the types of HPR catalysts may
change. Other unconventional crudes may include biofeeds, FischereTropsch syncrude,
and coal-derived liquids. Novel catalytic formulations will be necessary to achieve an
optimal HPR operation.
The catalysts used in the refining processes deactivate with time on-stream [8e12]. When
the activity of the catalyst declines below the acceptable level, it must be replaced with
either fresh or regenerated catalyst. However, it is not always economically attractive to
conduct regeneration of spent catalysts [7,13,14]. Thus, after several cycles of regeneration
and reuse, the catalyst activity recovery may decrease below acceptable levels. Therefore,
further regeneration may not be economically attractive. Then, other options for the spent
catalyst’s utilization have to be considered before it can be discarded as solid waste
[14,15].
Currently, the market for fresh HPR catalysts approaches 120,000tons per year. About
half of this amount has been used for the HPR of distillates to produce clean fuels,
whereas the other half has been used for residue upgrading [7]. The demand for HCR
catalysts is expected to grow at a rate of more than 5% per year. This would increase the
production of spent catalysts. Obviously, the quantity of spent catalysts discharged from
various processing units depends largely on the amount of fresh catalysts used and the
quality of feeds. Always, the amount of spent catalyst is generally greater than that of the
fresh catalyst because of the amount of deposits (coke and metals). For example, spent
catalysts from distillate-upgrading units contain typically 10e20% coke and 7e15% sulfur
together with some hydrocarbon carryovers [7]. Both organic and inorganic forms of
sulfur are present. In the case of residue HPR operations, metals such as Vand Ni present
Introduction 3
in the feed deposit on the catalyst together with coke. If dispersed solids are present in the
feed, they deposit on the front of catalyst fixed bed. The spent catalysts discarded from
these units usually contain 7e20% VþNi, 15e25% coke, 7e15% sulfur, and 5e10%
residual oil together with active metals (Mo and Co or Ni) and Al O originally present in
2 3
the catalyst. However, the amount of deposit on the catalyst may be decreased on the
refinery site by applying de-oiling and drying procedures before unloading spent catalyst
from reactor. According to the estimate made by Dufresne [7], the total quantity of spent
HPR catalysts generated worldwide is in the range of 150,000 to 170,000tons per year.
In addition to HPR, fluid catalytic cracking (FCC) and re-forming units may be another
source of solid spent catalysts on the refinery site. The feeds for these processes must be
subjected to HPR to minimize catalyst poisoning by nitrogen bases and metals. Because of
the hazardous nature, the procedures applied for handling of spent HPR catalysts may
differ from those used for the other types of catalysts. For example, the particle size of
spent FCC catalysts is much smaller than that of spent HPR catalysts. Therefore, all
precautions have to be taken during the handling of the former catalysts.
The reasons for a significant increase in the production of spent HPR catalysts in recent
years may be summarized as follows:
1. A rapid growth in the distillate hydrotreating capacity to meet the increasing demand
for ultralow-sulfur transportation fuels.
2. Reduced cycle times due to higher-severity operations in diesel hydrotreating units to
meet stringent fuel specifications.
3. A steady increase in the processing of heavier feedstocks having high sulfur, resin,
asphaltene, and metal contents to distillates by hydrogen addition technology.
4. Rapid deactivation and unavailability of reactivation processes for residue HPR catalysts.
With respect to (3), it is anticipated that the volume of heavy feeds entering refineries will
level off or even decline. Consequently, the consumption of HCR catalysts should
decrease. The amount of novel catalysts required for the HPR of unconventional feeds
may not offset the decreased amount from the HPR of heavy feeds. Therefore, overall, it is
not expected that the consumption of HPR catalysts will continue to grow. Of course,
these trends will vary from region to region.
Disposal of spent catalysts requires compliance with stringent environmental regulations.
Spent HPR catalysts have been classified as hazardous wastes by the Environmental
Protection Agency (EPA) in the United States. The EPA added spent hydrotreating catalyst
(K171) and spent hydrorefining catalyst (K172) to its hazardous waste list in August 1998
[16] because of their self-heating behavior and toxic chemical content. Spent HCR catalyst
was added to the list in 1999 [17,18]. Metals such as Co, Ni, and V that are present in
spent HPR catalysts from dual operations (e.g., simultaneous hydrotreating and HCR) are
