Download pdf - Hydroprocessing Catalysts from The Chevron and ... - · PDF fileEditor’s Note: Although this is only the second special issue of the Catalagram ® dedicated solely to hydroprocessing,

Hydroprocessing Catalysts fromThe Chevron and Grace Joint Venture

106 SPECIAL EDITION Fal l 2009

Editor’s Note:

Although this is only the second special issue of the Catalagram® dedicated

solely to hydroprocessing, we at Advanced Refining Technologies salute our sis-

ter publication, the Grace Davison Catalagram on the fiftieth anniversary of its

publication.

Advanced Refining Technologies has reaped the benefits of Grace Davison’s

long-standing technical leadership in refining catalyst manufacture and technical

service and strengthened it with the technology power of Chevron R&D and

process expertise.

As a result, ART has lept to a leadership position in hydroprocessing catalysis

since it was formed eight years ago. We offer a full range of HPC catalysts for

distillate and fixed bed resid hydrotreating and ebullating bed resid hydrocrack-

ing and are recognized as the industry leader in resid hydroprocessing technol-

ogy. Our technical service group, backed by both Chevron and Grace R&D, is

able to solve your most difficult processing issues.

We hope you find the information provided here helpful in your operations. Like

the Grace Davison Catalagram, we look forward to celebrating the 50th anniver-

sary of Advanced Refining Technologies leadership.

Sincerely,

Scott K. PurnellGeneral Manager and Managing DirectorAdvanced Refining Technologies

In this Special Issue of the CATALAGRAM®

The SmART Catalyst System™: Meeting the Challenges of Ultra Low Sulfur DieselBy Charles Olsen, Ph.D.In this reprint from Catalagram® 97 from 2005, we update commercial usage of theSmART Catalyst system, which utilizes both CoMo and NiMo catalysts, staged in theproper proportions to provide the best performance while at the same time meetingindividual refiner requirements. The catalyst staging is designed to take advantage ofthe different reaction mechanisms for sulfur removal. The article features an update oncurrent ULSD operations with the SmART Catalyst System Series.

Continued Improvements in Advanced Pretreating by ART With Our NewestFCC Pretreat Catalyst, AT795By Brian WatkinsAs challenges in meeting clean fuels regulations continue to become more daunting,Advanced Refining Technologies continues to improve its line of ultra high activity FCCpretreat catalysts for our ApARTTM Catalyst Systems. This article is an overview of theperformance of the newest member of our FCC pretreat family, AT795, which is capa-ble of significantly reducing required SOR temperatures for both HDS and HDN.

Cetane Improvement In Diesel Hydrotreatingby Greg Rosinski and Charles Olsen, Ph.D.This article discusses the importance of cetane in ULSD. The SmART Catalyst System,which utilizes both the CoMo and NiMo catalyst, results in a cetane uplift which is near-ly two numbers higher than an all-CoMo system with only a small increase in hydrogenconsumption. For H2 constrained refiners this is an ideal solution for improving theproduct cetane.

Hydrocracker Pretreat Catalyst DevelopmentBy Dave Krenzke, Ph.D, Jifei Jia, Ph.D., Charles Olsen, Ph.D, Brian Watkinsand Woody Shiflett, Ph.D.ART introduces the second generation DX™ catalyst for hydrocracker pretreat, 590DX,our new high performance technology aimed at helping refiners meet the challengespresented by clean fuels.

ART’s Latest Catalyst Technology for EB Resid HydrocrackingBy Balbir Lakhanpal, Darryl Klein, Pak Leung, Nan Chen, Pietro Grecoand Ashok MonteiroThe ebullating bed resid hydrocracking process has an advantage in that a wide varietyof crudes can be processed, allowing the upgrading of resid to almost saleable distil-lates, very good quality FCC/HC feed VGO, and low sulfur fuel oil. However, processingsuch opportunity crudes has its challenges, and ART has developed and commercial-ized its latest EB resid hydrocracking catalyst technology, HSLSTM, to help achieve thatgoal successfully and economically.

Advanced Refining Technologies’ Answers to 2009 NPRA Q&A Questionson HydroprocessingBy Charles Olsen, Ph.D., Brian Watkins, Gordon Chu, Woody Shiflett, Ph.D.,Dave Krenzke, Ph.D., and Geri D’Angelo

2

CATALAGRAM® 106SPECIAL EDITION

Managing Editors:Charles Olsen

andLauren Blanchard

Contributors:Nan ChenGordon ChuGeri D’AngeloPietro GrecoJifei Jia

Daryl KleinDave Krenzke

Balbir LakhanpalPak Leung

Ashok MonteiroCharles OlsenGreg RosinskiWoody ShiflettBrian Watkins

Please addressyour comments to

[email protected]

©2009W. R. Grace & Co.-Conn.

The information presented herein is derived from our testing and experience. It is offered, free of charge, for your con-sideration, investigation and verification. Since operating conditions vary significantly, and since they are not under ourcontrol, we disclaim any and all warranties on the results which might be obtained from the use of our products. Youshould make no assumption that all safety or environmental protection measures are indicated or that other measuresmay not be required.

Hydroprocessing Catalysts fromThe Chevron and Grace Joint Venture

106 SPECIAL EDITION Fal l 2009

Advanced RefiningTechnologies

7500 Grace DriveColumbia, MD 21044

410.531.4000

www.e-catalysts.com

10

12

17

20

25

rev.11/09

ARTCatalagram® 106 Special Edition Fall 2009 1

www.e-catalysts.com2

n 2001, ART introduced theSmART Catalyst System® Seriesto help refiners deal with the

severe demands of ultra low sulfurdiesel (ULSD). The SmART Systemutilizes state-of-the-art catalyst tech-nology which is staged in the properproportions to provide the best per-formance while at the same timemeeting individual refiner require-ments. The catalyst staging isdesigned to take advantage of the dif-ferent reaction mechanisms for sulfurremoval; ART CDX, a high activityCoMo catalyst, efficiently removes theunhindered, easy sulfur via the directabstraction route and ART CDY, a highactivity NiMo catalyst, then attacks theremaining sterically hindered, hardsulfur. Pilot plant work has proven thatthe properly configured SmARTSystem provides higher activity thaneither the CoMo or NiMo catalystalone.

The SmART Catalyst System®:Meeting the Challenges ofUltra Low Sulfur Diesel

Charles OlsenWorldwide Technical ServicesManager

ADVANCED REFININGTECHNOLOGIESChicago, IL USA

I ART CDX and ART CDY, individual-ly or as part of a SmART CatalystSystem, were selected for 14 dieselunits in 2004, and most of theseapplications aim to evaluate ULSDcapability and/or produce ultra lowsulfur fuels in advance of the regu-lations for economic benefit.

Optimizing the SmART CatalystSystem

An important aspect of the SmARTCatalyst System is determination ofthe optimum proportions of theCoMo and NiMo catalysts that willdeliver the best performance. Thisis dependent upon a number of fac-tors, including the refiners’ require-ments, and selected feed proper-ties and operating conditions asdiscussed in detail previously inCatalagram No. 95 (March 2004).


One clearly important parameterwhich must be considered is theboiling range of the feedstock.Sulfur speciation on a wide varietyof feedstocks has shown that thereis a strong correlation between thefraction of multi-substituted diben-zothiophenes (hard sulfur) and thefeed endpoint. Once the D86 end-point increases beyond about625°F there is a rapid increase inthe fraction of hard sulfur containedin the feed. This has a large impacton catalyst activity as shown inFigure 1. The figure shows pilotplant data comparing results fromtreating two feeds with differentendpoints over the same catalystunder identical conditions. At ultralow sulfur levels there is about 30˚Fdifference in reactivity of the twofeeds with the lower endpoint feedmore reactive. Clearly, feed end-point and the amount of hard sulfurare critical parameters that influ-ence the optimum SmART configu-ration.

Another critical feed property thatmust be accounted for is the nitro-gen content. It is generally accept-ed that nitrogen inhibits aromaticsaturation reactions through poison-ing of acidic sites on the catalyst.Recall that the primary reactionpathway for removal of hard sulfur isvia hydrogenation of an aromaticring, and it is not surprising thatfeed nitrogen content has a serious,negative impact on HDS activity.

The magnitude of the impact can beseen in Figure 2 which summarizesdata for a NiMo and a CoMo catalystactivity on an SR feed before and afterselectively removing the nitrogen viaan adsorption process. The differ-ence in activity on the two feeds isquite large. Increasing the nitrogencontent from 25 to 160 ppm results ina loss in HDS activity of 40-50˚F forboth catalysts. Comparing the cata-lysts on the low nitrogen feed showsthat the NiMo catalyst has about 15˚Fhigher activity relative to the CoMocatalyst, and that decreases to anadvantage of about 5˚F or less on thehigher nitrogen feed. This suggeststhe impact of nitrogen is different forNiMo and CoMo catalysts with theCoMo catalyst more tolerant of nitro-

gen. This is another important con-sideration when designing the opti-mum SmART System.

Hydrogen availability, in terms ofhydrogen pressure and hydrogencirculation, also takes on greaterimportance in ULSD. Figure 3 is achart showing how the relative HDSrate constant changes as a functionof the excess hydrogen (H2/Oil ratiodivided by the hydrogen consump-tion) for both high and low pressureoperation. Note the range in operat-ing pressure from low to high repre-sents the conditions typicallyencountered in diesel hydrotreating.At high pressure, increasing theH2/Oil is beneficial for both SR and20% LCO feeds up to a point, afterwhich further increases in H2 rateprovide little additional benefit. Atlow pressure, the effect of H2/Oilratio is quite different. In that case,the relative rate constant for bothfeeds shows a steady increase withincreasing hydrogen rate. The ben-efit of increasing H2/Oil neverreaches a plateau as observed inthe high pressure case indicatingthat more hydrogen is always betterat low pressure. The effect of pres-sure is also readily apparent in thefigure. Comparing the relative rateconstant for high and low pressureat a typical H2/Oil ratio reveals thatthe activity at low pressure is only

Figure 1Feed Endpoint Impacts HDS Activity

Tem

per

atu

re,˚

F

1

Product Sulfur, ppm

10 100 1000

675˚F D86 EP

735˚F D86 EP

19˚F

31˚F

Figure 2Nitrogen Impacts Catalysts Differently

160 ppm Nitrogen

CoMo

0

10

20

30

40

50

Rel

ativ

eA

ctiv

ity,

˚F

Base

25 ppm Nitrogen

NiMo


10-20% of that at high pressure for20% LCO and SR feed respectively.

Controlling HydrogenConsumption

One of the key advantages of theSmART System is the efficient use ofHydrogen. Figure 4 illustrates howthe system can be tailored to pro-vide the best balance of high HDSactivity while minimizing H2 con-sumption. The figure shows that asNiMo catalyst is added to the sys-tem there is a large increase in HDSactivity relative to the all CoMo refer-ence, and eventually, a minimum inthe product sulfur curve is reached(i.e. maximum HDS activity). Theposition and magnitude of this mini-mum varies with feed and operatingconditions such as those discussedabove. The figure also shows therelative H2 consumption, and again,as the percentage of the NiMo com-ponent increases, the H2 consump-tion relative to the base CoMo sys-tem increases. In the region wherethe system shows the best activity,the hydrogen consumption is onlyslightly greater than that for the allCoMo system, and well below thatfor the all NiMo catalyst. This is aresult of the different kinetics for sul-fur and aromatics removal and is acritical consideration when cus-tomizing a SmART System.

To help understand the differences inkinetics it is useful to compare theperformance of CoMo and NiMo cat-alysts alone. Figure 5 shows a com-parison of the hydrogen consump-tion over a NiMo and CoMo catalystfor a straight run feed at ULSD condi-tions. The amount of hydrogen con-sumed by sulfur, nitrogen and olefinsremoval is essentially the same foreach catalyst and is not shown.What separates the two catalysts isthe amount of aromatics saturationwhich occurs, and in particular, theamount of mono ringed aromaticswhich are hydrogenated. In thiscase, an additional 70 SCFB ofhydrogen is consumed with the NiMocatalyst due to mono ringed aromat-ics saturation. This representsexcess hydrogen consumption

Figure 3Hydrogen Availability is Critical

H2: Oil Ratio/H2 ConsumptionR

elat

ive

HD

SR

ate

Co

nst

ant 100

80

60

40

20

0

20180 161412108642 22 24 26 28

120

SR20% LCO

Low Pressure

High Pressure

Figure 4Balancing HDS Activity and H2 Consumption

SmART SystemsAll CoMo

Reference

Pro

du

ctS

ulf

ur,

pp

m

1.00

1.15

All NiMoReference

Relative

H2

Co

nsu

mp

tion

Figure 5Excess H2 Consumption with SR Feed in ULSD

NiMo

HDSHDN

Poly aromatics

CoMo

HDN

HDS

Poly aromaticsMono aromatics

Mono aromatics

OlefinsOlefins

165 Scfb190 Scfb

165 Scfb120 Scfb


above that required for the removal ofsulfur.

Figure 6 is a similar chart for LCGOfeed. In this example, the NiMo cat-alyst hydrogenates more PNA (2rings and greater) and mono ringedaromatics compared to the CoMocatalyst accounting for an addition-al 110 SCFB of hydrogen consump-tion above that required for sulfur,nitrogen and olefins removal.Clearly, in cases where hydrogenconsumption needs to be mini-mized, a NiMo catalyst for ULSD isthe wrong choice. Unfortunately, inmany of these cases a CoMo cata-lyst does not provide the best activ-ity for ULSD, and it is preciselythese units where the SmARTSystem is ideal as it offers the high-est activity and is more efficient withhydrogen compared to an all NiMosystem.

It perhaps appears contradictorythat a NiMo catalyst is included inthe SmART System due to its highhydrogenation activity making itpreferred for hard sulfur removal,and yet, under some conditions thehydrogenation activity is too highand excess aromatics saturationoccurs. This highlights one of thekeys to designing the proper sys-tem. The design involves increasingthe hydrogenation selectivity of thesystem to provide highest HDS

activity, while at the same time mini-mizing hydrogen consumption (i.e.minimizing excess aromatics satura-tion).

Figure 7 shows a schematic of thereaction pathway for poly aromaticssaturation. Naphthalene, a two ringedaromatic molecule, is featured at thetop of the figure. The reaction beginswith the hydrogenation of one of thearomatic rings to form tetralin, a monoring aromatic. The next reaction in thesequence is hydrogenation of theremaining aromatic ring to producedecalin, a fully saturated molecule.Each step is reversible and subject toequilibrium constraints. The slowest

reaction in the sequence is the sat-uration of the mono ring aromatic.The reaction sequence for a substi-tuted biphenyl is also shown at thebottom of the figure. The sequenceis essentially the same. In bothexamples the hydrogenation of themono aromatic is the slowest stepand also consumes more hydrogencompared to the other hydrogena-tion reactions shown; three moles ofhydrogen per mole of aromatic areconsumed by the saturation of themono ring aromatic compared withtwo moles of hydrogen/mole for themulti ringed aromatics.

The reaction sequences shown inFigure 7 can be treated as a seriesof first order reversible reactionswhere the intermediate (the monoring aromatic) is the desired prod-uct. For these sorts of reaction sys-tems the intermediate often tends tobe favored at shorter contact times(see Chemical ReactionEngineering by Octave Levenspiel[Wiley, 1998], for example), and it isthis tendency which is exploitedwhen customizing a SmARTSystem. The effective residencetime in both the CoMo and NiMobeds of a system is short comparedto the overall reactor residencetime, and this helps minimize thehydrogenation of the mono ring aro-matic (i.e. minimize hydrogen con-sumption).

Figure 6Excess H2 Consumption with LCGO Feed in ULSD

NiMo

HDSHDN

Poly aromatics

275 Scfb

CoMo

HDN

HDS

Poly aromaticsMono aromatics Mono aromatics

OlefinsOlefins

130 Scfb250 Scfb 45 Scfb

Figure 7Reaction Sequence for Poly Aromatics Hydrogenation

k2

k3 k4

k1 > 10 x k2

k3 10 x k4

k1

~~


Figure 8Limiting Aromatics Saturation

60

65

70

75

80

85

0.0 0.5 1.0 1.5 2.0 2.5 3.0

1/LHSV, hr

PN

AC

on

vers

ion

2

4

6

8

10

12

14

16

18

Mo

no

arom

aticsC

on

version

PNAMono

Table ICommercial Experience with ART CDX, CDY and the SmART Catalyst System

Refiner 1 2 3 4 5 6 7 8

Pilot Testing Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes

Startup Date 4Q04 4Q04 4Q04 2Q05 2Q04 3Q04 1Q05 2006 2006 2006 2006 2006 2006

Catalysts CDX CDX CDX CDX CDX CDX CDX CDX CDX CDX CDX CDX CDX

CDY CDY CDY CDY CDY CDY CDY CDY CDY CDY

Feedstock:% cracked stock 40 10-20 0 0 30 0 10 100 0 0 36 60 0

API 32.5 34.7 35.6 31.8 30.5 34.3 36.0 26.5 32.1 41.1 31.6 26.9 38.4

Sulfur, wt.% 1.66 0.99 0.07 1.26 0.34 1.26 1.00 0.90 0.86 0.82 0.87 0.89 0.83

EP D86 Dist, ˚F 700 710 635 745 670 715 680 680 695 545 655 685 660

Product:

Sulfur, ppm 7 7 8 10 10 35 50 7 7 7 7 7 7

Conditions

LHSV 0.7 1.5 2.8 0.7 1.1 1.6 1.9 1.0 1.1 2.6 1.3 1.0 1.6

Inlet P, psig 800 940 700 825 825 750 650 1290 820 600 1070 1290 740


Figure 8 shows the effect of resi-dence time, as indicated by 1/LHSV,on aromatics saturation. For PNAsaturation, the two ringed aromaticgoing to the mono ring aromatic,there is a fairly steep curve for con-version as a function of residencetime below about 1 hr. Above thatpoint, which represents spacevelocities of 1 hr-1 or less there isvery little change due to equilibriumconstraints. For mono ring aromaticsaturation there is a steady increasein conversion as the residence timeis increased indicating more andmore saturation as the residencetime is increased (i.e., LHSV isdecreased). Both sets of curvessuggest aromatic saturation can belimited by appropriate choice ofLHSV, or in the case of a SmARTSystem, by adjusting the relativequantities of CoMo and NiMo cata-lyst.

SmART System Experience

The SmART System is the culmina-tion of an extensive effort puttowards understanding the chem-istry and process conditionsrequired for ultra low sulfur fuels. Inaddition, properly designed highactivity catalysts must be used inorder to take full advantage of theSmART System concept. ART hasdevoted significant resources todesigning the best ULSD catalystsfor use in the SmART System, andthis effort has lead to the commer-cialization in 2004 of a new CoMocatalyst CDX, and a new NiMo cata-lyst CDY. These new technologiesbenefit from the optimization of thealumina chemistry to give the rightsurface area and pore size distribu-tion, as well as providing the rightsurface chemistry (i.e., acidity).

ULSD production with the CDX/CDYSmART System began early in2004, in a North American refineryprocessing a feed containing 20-40% of a high endpoint LCO. Sincethat time, CDX and CDY have beenselected for 14 different dieselapplications either as componentsin SmART Systems or as a completecharge. A list of commercial appli-cations of CDX, CDY and SmART

Systems is shown in Table I. It isapparent from the table that theSmART catalyst technology has beensuccessfully applied to a wide rangeof feeds and conditions. In mostcases it has been selected based onthe high activity demonstrated in pilotplant testing.

As these and other recent successesdemonstrate, Advanced RefiningTechnologies has developed state-of-the-art technologies aimed at helpingrefiners meet the challenges of cleanfuels. These successes are the resultof harnessing the unique heritage ofART which includes a collectiveexpertise in material science, catalystformulation, and manufacturing know-how. The science of designing specif-ic catalyst components to operate inan optimum system is a fundamentalpart of ART's catalyst technology.With the advent of clean fuels, ARTseized the opportunity to extrapolatetheir catalyst system expertise fromresid to lighter feedstocks. As a result,ART has been able to deliver high per-formance technologies ranging from

StARTTM Systems for Si tolerance incoker naphtha applications, SmARTSystems for ULSD, and ApARTTM

Catalyst Systems for cat feedhydrotreating.

ART strives to continuously improvethe performance of its catalysts,and the current focus of that effortis on maximizing the effectivenessof the catalytic metals. Asdescribed in Catalagram No. 96(October 2004), ART's new CoMocatalyst, CDX, benefits fromimproved metals utilization throughthe application of novel metalschemistry and a unique impregna-tion technique. These same tech-niques have been successfullyapplied to a new NiMo catalystcalled an NDXi. As shown in Figure6, this catalyst has significantlyhigher activity for ULSD than ARTCDY and the conventional referenceNiMo catalyst.

NDXi, commercialized in early 2005,has become the NiMo catalyst com-ponent of the SmART System.

Figure 9ART NDXi Has “Step Out” Activity

80

100

120

140

160

180

200

NDXi CDY Reference NiMo

Rel

ativ

eV

olu

me

Act

ivit

y HDS

HDN

Editor’s Note:

A lot has changed since ART first introduced he SmART Catalyst System® series for ULSD in 2001. Many ULSD unitshave been built or retrofitted and are now into their second or third cycles. Most countries in the world are either man-dating ULSD from their refineries, or in the process of doing so.

ART has made many improvements in its offerings for making ULSD as a result of extensive investment in theresearch and development of new and improved catalysts for expanding performance and flexibility. Since the intro-duction of CDY and CDX, ART is already on its third generation of catalysts. The premier catalysts used in today’sSmART system are 420DX and NDXi.

The table below shows the commercial experience of the SmART System. There are many repeat users among themore than 70 unit start-ups that have occurred using the SmART catalyst system. A wide variety of feedstocks andoperating conditions are represented from units all over the world.

Country/RegionStart-up

Date% Cracked

StockProduct Sulfur

(ppm)Pressure

(psig)% NiMoCatalyst

Mid Continent, USA

Japan

Japan

Japan

Mid Continent, USA

Mid Continent, USA

Japan

Japan

Korea

Russia

South Africa

West Coast

Mid Continent, USA

Eastern Canada

South America

Korea

Russia

Mid Continent, USA

Mid Continent, USA

Gulf Coast, USA

Gulf Coast, USA

Gulf Coast, USA

Western Canada

2004

2004

2004

2004

2004

2005

2005

2005

2005

2005

2006

2006

2006

2006

2006

2006

2006

2006

2006

2006

2006

2006

2007

0

10-20

40

0

20

15

35

0

10

15

0

35-50

36

60

100

0

0

15

8

7

7

35

10

7

7

10

50

400

7

7

25

8

50

7

7

7

7

7

9

700

940

800

750

825

750

1270

825

650

770

740

2100

1260

850

700

1070

1290

1290

820

600

890

35%

55%

25%

0%

25%

25%

100%

100%

10%

30%

15%

100%

0%

30%

100%

50%

25%

0%

67%

67%

67%

0%

30%

SmART Catalyst System Users List


Country/RegionStart-up

Date% Cracked

StockProduct Sulfur

(ppm)Pressure

(psig)% NiMoCatalyst

Gulf Coast

United Kingdom

Mid Continent, USA

Taiwan

Korea

Japan

South America

South America

Korea

Korea

Korea

Singapore

Russia

Russia

Russia

Thailand

Thailand

Russia

South Africa

Gulf Coast, USA

India

India

Thailand

Korea

Korea

Gulf Coast, USA

Russia

Australia

United Kingdom

Gulf Coast, USA

Chile

Gulf Coast, USA

Japan

Poland

Singapore

Singapore

East Coast, USA

Russia

Taiwan

Taiwan

Mid Continent, USA

2007

2007

2007

2007

2007

2007

2007

2007

2007

2007

2007

2007

2007

2007

2007

2008

2008

2008

2008

2008

2008

2008

2008

2008

2008

2008

2009

2009

2009

2009

2009

2009

2009

2009

2009

2009

2009

2009

2009

2009

2010

50

32

60-100

0

0

35

0

0

0

15

10

10

15

60

10

0

0

0

0

0

40

30-40

40

60

10

30

0

10

40

35

350

5

8

450

10

7

25

25

8

8

8

7

8

50

50

45

45

50

400

15

50

50

50

8

8

7

50

8

8

4

10

4

10

3000

7

20

50

450

5

7

1000

780

1600

610

1140

1270

780

780

825

770

940

950

725

465

650

870

870

650

770

1000

745

740

609

850

754

820

570

725

580

1070

1400

950

340

950

395

650

600

755

750

50%

50v

70%

0%

70%

100%

100%

100%

70%

10%

10%

0%

25%

0%

45%

70%

70%

45%

15%

50%

65%

0%

0%

10%

50%

0%

0%

33%

0%

100%

100%

20%

0%

60%

0%

70%

0%

30%

0%

100%

50%


Brian WatkinsTechnical Service Engineer


dvanced Refining Techno-logies® (ART) first introducedthe ApARTTM catalyst system

for superior FCC feed pretreating in2002. The ApART technology wasdesigned to provide maximum HDSactivity while also providing significantupgrading of FCC feeds. This tech-nology has been widely accepted withover 50 units in commercial servicesince its inception. As challenges inmeeting clean fuels regulations con-tinue to become more daunting,Advanced Refining Technologies con-tinues to improve its line of ultra highactivity FCC Pretreat catalysts, andstrives to provide refiners with superi-or technology and first-class perform-ance.

ART’s AT575, AT775 and AT792 cat-alysts have long proven their per-formance advantage of outstandingstability and exceptional ability toprovide consistent, high quality feedfor their FCC units. In keeping withthis tradition, ART is introducing itsnewest ultra high activity VGO cata-lyst, AT795. Figure 1 compares theactivity of several FCC pretreat cat-alysts supplied by ART includingthe newest catalyst, AT795. Theresults from side-by-side testing ofAT575 and AT795 clearly show thatAT795 outperforms AT575 by almost150% for HDS while maintainingsimilar activity for HDN.

Continued Improvements inAdvanced Pretreating by ARTwith Our Newest FCC PretreatCatalyst, AT795

A


This newest member to the FCCpretreat family is capable of signifi-cantly reducing required SOR tem-peratures for both HDS and HDN.AT795 offers refiners a significantboost in its ability to generate lowsulfur FCC products as well asdeliver the benefits of nitrogenremoval and poly aromatic satura-tion. Taking advantage of the syn-ergistic effects in ApART by com-bining AT795 with AT575 providesunlimited opportunities for FCC feedupgrading.

An additional benefit of AT795 isimproved aromatic saturation activi-ty. Comparing an ApART systemwith AT795 to a system with AT792clearly shows increased conversionof aromatics in FCC pretreat appli-cations. This increase in aromaticssaturation translates to improvedFCC feed quality and increasedyields from the FCC operation. Thepilot plant work shown in Figure 2used a feedstock with 1.5 wt.%Sulfur and 4700 ppm nitrogen.

AT795 is a NiCoMo catalyst that hasoutstanding HDS activity coupledwith high HDN activity. This catalyst

provides superior HDS performancein order to meet stringent gasoline sul-fur regulations while also allowingrefiners to benefit from improved FCCfeed upgrading typically only found inpure NiMo applications. Refinerslooking to add more hydrogen to their

FCC feeds for additional conversionare going to reap the benefits ofcombining AT795 with AT575 in anew and improved ApART system.

Figure 1Advanced Refining Technologies line of

High Performance Catalysts for FCC Pretreat

Rel

ativ

eVo

lum

eA

ctiv

ity,%

HDS HDNHHH

60

70

80

90

100

110

120

130

140

150

AT575 AT775 AT792 AT795

Figure 2Comparison of two ApART Catalyst Systems

with AT575 and AT792 or AT795 for Aromatic saturation

Aro

mat

icC

on

vers

ion

,%

WABT, ˚F

25%

30%

35%

40%

45%

50%

75% AT575 / 25% AT792 75% AT575 / 25% AT795


emand for higher performancein diesel engines has resultedin an increase in minimum

cetane numbers for diesel fuel. It isexpected that the desire for highercetane will continue as indicated bythe recommendations of the WorldWide Fuels Charter. Thus, it is impor-tant for refiners to understand theeffects of both feedstock and pro-cessing parameters on the cetane ofdiesel fuel to enable them to moreeffectively manage their distillatehydrotreating units to meet ever morestringent fuels specifications.

While some diesel is produced inhydrocrackers, the vast majority ofdiesel is processed in dieselhydrotreaters (DHT’s) which usuallyco-process streams such as FCC

Cetane Improvement In DieselHydrotreating

Greg RosinskiTechnical Services Engineer



DLCO, LCGO, SR diesel, andKerosene. The units processingsignificant amounts of crackedstocks need special attention inorder to meet product cetanerequirements. To understand whythis is so it is necessary to knowwhat cetane is, and how the differ-ent molecular species influence it.

The cetane number is a measure ofthe ignition quality of diesel fuel andis based upon the compoundcetane or hexadecane which isassigned a cetane number of 100.It is analogous to the octane num-ber in gasoline. Gasoline octaneincreases with olefin, aromatic, andiso-paraffin contents, whereascetane number increases withparaffin and naphthene contents.



Table ICetane Number of Pure Compunds

Compound Formula CetaneNumber

n-Decane C10H22 76n-Pentadecane C15H32 95

Paraffins

n-Eicosane C20H42 1103-Ethyldecane C12H26 484,5-Diethyloctane C12H26 20Heptamethylnonane C16H34 158-Propylpentadecane C18H38 487,8-Diethyltetradecane C18H38 67

Isoparaffins

9,10-Dimethyloctadecane C20H42 59Decalin C10H18 483-Cyclohexylhexane C12H24 362-Methyl-3-cyclohexylnonane C16H32 70

Naphthenes

2-Cyclohexyltetradecane C20H40 571-Methylnaphthalene C11H10 0n-Pentylbenzene C11H16 8Biphenyl C12H10 211-Butylnaphthalene C14H16 6n-Nonylbenzene C15H24 502-Octylnaphthalene C18H24 18

Aromatics

n-Tetradecylbenzene C20H34 72

Thus, a fuel with a high cetane valuehas low octane and visa versa.

Table 1 lists some pure compoundsand their corresponding cetanenumber. As can be seen, paraffins,particularly normal paraffins, havevery high cetane numbers whilearomatics, especially naphthalenetype aromatics, have very lowcetane numbers. Certain distillaterange materials like FCC LCO arehigh in naphthalenes whichexplains the low cetane number ofLCO feedstocks.

The actual cetane number is rarelyanalyzed in refineries since itrequires a specialized motor for itsdetermination. Most refiners’ usecetane index, typically, ASTM D-976and ASTM D-4737. D976 uses theAPI gravity and the 50% distillationpoint, whereas D4737 uses thegravity with the 10%, 50% and 90%distillation points. The two equa-tions are shown below.

ASTM D-976cetane index = -420.34+0.016*API2

+0.192*API*log(T50)+65.01*log(T50)–0.0001809 *T502

Where T50 is the D86 50% point indegrees °F

ASTM D-4737Cetane index= 45.2+0.0892*(T10-215)+[0.131+0.901* B]*[T50-260]+ [ 0 . 0 5 2 3 – ( 0 . 4 2 0 ) * ( B ) * ] [ T 9 0 -310]+[0.00049]*[(T10-215)2

–(T90-310)2] + (107)*(B) + (60)*B2

Where: B = Exp[-3.5*(sp. gr. – 0.85)] –1 and the D86 temperatures are in °C

Figure 1 compares the cetane index(D976) for a number of different distil-late feed sources. It is readily appar-ent that FCC LCO’s have the lowestcetane while straight run (SR) materi-als have the highest cetane. Distillatefeeds derived from coking operationstend to have a cetane similar to SRmaterial, while kerosene tends to havesomewhat lower cetane owing to thelower boiling point. For the diesel

range materials, the feeds withlower API gravity (LCO) have lowercetane index demonstrating thatwithin a given boiling range the APIis a reasonable tool for estimatingthe cetane index.

Figure 2 shows the cetane index asa function of poly aromatics contentfor a variety of distillate feeds. TheLCO’s clearly have the highest con-centration of poly aromatics andcorrespondingly lower cetaneindex. The SR, LCGO and vacuumbottom gas oil (VBGO) all have con-siderably lower PNA content withhigher cetane index values com-pared to the LCO’s. Keroseneshave very low polynuclear aromatics(PNA) content, but because of thelower molecular weight (kerosenegenerally has compounds contain-ing less than 16 carbon atoms) thecetane index is slightly lower thanfor SR diesel material. The figuresmake it clear that when it comes tocetane, LCO is a problem due to thehigh PNA content.

Figure 1Cetane Index of Various Distillate Feeds

5 10 15 20 25 30

Feed API

Cet

ane

Ind

ex(D

976)

35 40 45 50

LCO

10

15

20

25

30

35

40

45

50

55

60

LCGO/VBGO Straight Run Kerosene

Figure 2Cetane Index and Polynuclear Aromatics (PNA’s)

Feed PNA’s, vol.%

Fee

dC

etan

eIn

dex

(D97

6)

LCO LCGO/VBGO Straight Run Kerosene

10

15

20

25

30

35

40

45

50

55

60

0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75

Figure 3Effect of LHSV on Cetane in a Variety of Commercial Units

LHSV

Del

taC

etan

eIn

dex

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Refiner A Refiner B Refiner C Refiner D Refiner E Refiner F

Treating feedstocks that containLCO will become more challengingas LCO yields increase and cetanerequirements become more strin-gent. With this in mind, it is useful tosurvey the level of performance cur-rently being achieved in commercialdiesel hydrotreating units today.This will help to define what the rea-sonable level of cetane uplift thatcan be expected is, and if there is apractical maximum uplift that canbe achieved via hydrotreating. It isalso useful to ascertain whethercurrent operations indicate ifcetane changes (decreases) duringthe cycle. All of these are importantquestions for refiners interested inincreasing diesel yields from lowerquality feedstocks.

There are a number of parameterswhich influence cetane improve-ment in the diesel hydrotreater.Hydrogen partial pressure andLHSV are key operating conditionswhich effect the product cetane.Catalyst selection also plays animportant role since at higher pres-sures NiMo catalysts have a higherPNA saturation activity compared toCoMo catalysts.

Figures 3 shows the level of cetaneincrease (measured by delta cetaneindex) that has been achieved com-mercially as a function of unit LHSV.Generally speaking, as LHSVdecreases the potential cetaneimprovement increases. At a LHSVaround 1 hr-1 or less, cetane indexincreases of 10 or more numbersare achievable (provided the H2pressure is high enough), while at aLHSV greater than about 1.7 hr-1the cetane improvement is about 4numbers or less.

Figure 4 summarizes the cetaneincrease as a function of unit pres-sure. Not surprisingly, higher pres-sure units tend to achieve muchlarger cetane increases. In theseexamples, the cetane uplift is typi-cally less than 6 numbers when theunit pressure is less than 1000 Psig.Cetane uplift increases to 8-10 num-bers as pressure increases beyond1000 psig. The data in Figures 3



Figure 4Effect of Unit Pressure on Product Cetane

Reactor Inlet Pressure, Psig

Del

taC

etan

eIn

dex

Refiner A Refiner B Refiner C Refiner D Refiner E Refiner F

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

9.0

10.0

11.0

12.0

13.0

14.0

400 600 800 1000 1200 1400 1600 1800 2000 2200

Figure 5Feed API Has a Significant Impact on Cetane Uplift

Feed, API

Del

taC

etan

eIn

dex

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

16 18 20 22 24 26 28 30 32 34 36 38 40 42 44

Refiner A Refiner B Refiner D Refiner E Refiner F

Figure 6API Uplift and Cetane Increasefor Several Commercial Units

Delta, API

Del

taC

etan

eIn

dex

Refiner A Refiner B Refiner D Refiner E Refiner F

0

1

2

3

4

5

6

7

8

9

10

11

0 1 2 3 4 5 6 7 8 9 10

and 4 also suggest there might be apractical limit to cetane improve-ment achieved from typicalhydrotreating. Comparing thecetane uplift achieve by Refiners Aand C shows about 8-10 numberimprovement for both units despitethe difference in operating pressureat similar LHSV.

Figure 5 summarizes the commer-cial data in another way. It showshow the cetane increase correlateswith the API gravity of the feed. Ingeneral, the cetane uplift increasesas the feed API decreases. Figure 6shows how the observed APIincrease correlates with the cetaneindex increase. This data showsthat the API uplift is a reasonablepredictor for the cetane increase.

The hydrogen consumption isanother important considerationwhen discussing cetane improve-ment. There is a general rule ofthumb that says the hydrogen con-sumption is roughly equal to (100*API Uplift) or (100* Cetane uplift).Averaging the H2 consumptionrequired for the observed cetaneincrease with the units discussedhere indicates that the H2 consump-tion varies from about (80*Cetaneuplift) at low pressure (Refiner D) to(150-175* Cetane uplift) for the highpressure units (Refiners A & C). Thedata suggests the rule of thumb is areasonable estimate for H2 con-sumption for units operating belowabout 1000 psig.

These data demonstrate that as theunit conditions (LHSV and pressure)get more favorable for PNA satura-tion, the cetane uplift increases.However, is cetane uplift constantduring an entire cycle?

Figure 7 summarizes the observedcetane from three ULSD units cur-rently using SmART systems.Refiner A is a high pressure unit witha LHSV around 1. The feed to thisunit contains 40-50 vol.% LCO. Thisunit has not experienced a signifi-cant decline in cetane uplift duringthe cycle. Refiner B is a higherLHSV unit, with a lower pressure

Figure 7Variation in Cetane Uplift During a Cycle

Days on StreamD

elta

Cet

ane

Ind

exRefiner A Refiner B Refiner C

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

0 100 200 300 400 500 600 700 800 900 1000 1100

Figure 8The Catalyst System Has a Huge Impact on Cetane Uplift

Temperature, ˚F

Cet

ane

Ind

exIn

crea

se

NiMo CoMo SmART

4

5

6

7

8

9

10

11

12

13

14

15

620 625 630 635 640 645 650 655 660 665 670

than Refiner A, but the feed is rela-tively light with about 35-40 vol.%LCO and LCGO. Despite the lowerpressure and higher LHSV, thisrefiner also did not see an apprecia-ble decline in cetane uplift duringthe cycle. Refiner C is a higherpressure unit with a lower LHSVcompared to Refiner B. The feed ishigh in sulfur with large (>80 vol.%)amounts of cracked stock, espe-cially LCO. This unit does show aslow, steady decline in cetane uplift;the cetane uplift is 2-3 numberslower after more than two years onstream. This suggests that unitswith difficult feeds containing highfractions of LCO and other crackedstocks, or units without sufficienthydrogen, will experience decreas-ing cetane uplift during the cycle.

As mentioned previously, the cata-lyst system will also have an impacton the degree of cetane upliftachieved in a hydrotreater. It iscommon knowledge that NiMo cata-lysts have a higher saturation activi-ty than CoMo catalysts, and there-fore a NiMo catalyst is expected todeliver greater cetane uplift. Figure8 summarizes pilot plant data whichdemonstrates this. These data weregenerated using a 50% LCO con-taining feed, and shows that theNiMo catalyst results in almost twicethe cetane uplift compared to theCoMo catalyst. The SmART CatalystSystem, which utilizes both theCoMo and NiMo catalyst, results ina cetane uplift which is nearly 2numbers higher than the all CoMosystem with only a small increase inhydrogen consumption. For H2 con-strained refiners this is an idealsolution for improving the productcetane.



Dave KrenzkeRegional Technical ServicesManager

Jifei JiaSenior Research Engineer


Brian WatkinsSupervisor, HydrotreatingLaboratory Services

Woody ShiflettDirector of Global Marketing

ADVANCED REFININGTECHNOLOGIES

he stringent legislation that hasbeen enacted in many parts ofthe world for clean fuels has

demanded that refiners produce fuelswith very low levels of sulfur. In orderto meet refiners increasing needs, sig-nificant improvements in hydropro-cessing catalysts are needed. In orderto synthesize and develop highly effi-cient hydroprocessing catalysts forthis service, an in-depth understand-ing of the relationship between cata-lyst structure and catalytic activity isneeded1.

In 2001, Grace and Chevron formedAdvanced Refining Technologies® toprovide world class hydrotreating cat-alyst technology for the refining indus-try. Since its inception, ART has con-centrated on developing high per-formance technologies aimed at help-ing refiners meet the new challengespresented by cleaner fuels. This haslead to the introduction of several newtechnologies including the SmARTsystem for ULSD , the ApARTTM cata-lyst system for FCC pretreating, andhigh activity catalysts for hydrocracker

pretreat applications. Continuingthis effort, ART is introducing itssecond generation DX™ catalyst forhydrocracker pretreat, 590DX, in2009.

Hydrocracker Pretreat CatalystDevelopment

Good hydrodenitrogenation (HDN)activity is the primary function of ahydrocracker pretreater as organicnitrogen compounds are detrimen-tal to the performance of the down-stream hydrocracking (HCR) cata-lyst. The rate limiting step in theHDN reaction pathway is aromaticring saturation. This is because themost refractory nitrogen com-pounds are pyridine structureswhere the nitrogen atom is incorpo-rated into the aromatic ring. Thedevelopment of an improved HDNcatalyst therefore needs to focus onthe properties that enhance ringsaturation. Two key considerationsin the endeavor are active metalsutilization and optimization of cata-lyst support properties.

T

Hydrocracker PretreatCatalyst Development

Figure 1Historical Development of Hydrocracker Pretreat Catalysts

HD

NA

ctiv

ityIm

prov

emen

t,˚F

590DX

1972 1988 1996 2001 2003 2006 20092003 2006 2009

ART Joint Venture

NDXi

Base

+ 10

+ 20

+ 30

AT540AT580

Figure 2VGO HDN Activity Comparison

Time on Stream, hours

No

rmal

ized

HD

NT

emp

erat

ure

,˚F

AT580 NDXi 590DX

0

5

10

15

20

25

30

35

40

45

50

0 100 200 300 400 500 600 700 800 900 1000

The current generation ofhydrotreating catalysts relies on theformation of Type II active sites dur-ing catalyst activation. Type II sitesare known to provide significantlyhigher activity at the same metalsloading as catalysts containingType I active sites. An effective wayto maximize the concentration ofType II active sites is through theuse of chelate technology duringthe metals impregnation step of cat-alyst manufacture. ART has beensteadily improving the application ofchelates as detailed in Catalagram#96, 2004. To further improve theeffectiveness of these new chelatedcatalysts, the support must bedesigned to enhance the chelatechemistry as well as tailored for theoptimum surface area and porestructure for the targeted applica-tion.

Figure 1 summarizes the progres-sion of hydrocracker pretreat cata-lyst technology through the years.As can be seen, there has been sig-nificant innovation since the forma-tion of the ART joint venture in 2001.NDXi is the first catalyst in thisseries to utilizes ARTs’ chelate tech-nology.

NDXi is an ultra high activity catalystfor hydrocracker pretreat and ULSDapplications. This catalyst has beenselected for more than 50 units forULSD and hydrocracker pretreat sinceits commercialization in 2005. NDXiwas selected for many of these appli-cations through competitive pilot planttesting where the performance advan-tages were easily demonstrated. NDXihas shown significant HDN activityadvantages over the previous genera-tion catalyst, AT580. Since the level ofactive metal is similar for both cata-lysts, it is a good demonstration thatchelate technology offers incredible

potential for producing highly activesites compared to conventional(non chelated) catalysts.

Figure 2 compares the VGO HDNactivity of AT580, NDXi and thenewest catalyst, 590DX. This pilotplant comparison was completedon a VGO with a final boiling pointabove 1100˚F, and it contained 1150ppm nitrogen and 2.7 wt.% sulfur.The conditions represent an accel-erated aging condition and the dataare normalized to 1 ppm productnitrogen. It is clear from the figurethat 590DX has more than 10˚Fhigher HDN activity than NDXiunder these severe conditions.

Figure 3 summarizes more pilotplant data which compares 590DXwith NDXi on a variety of VGOfeeds. The nitrogen content of thefeeds ranges from 600 to 1200ppm, and the sulfur content variesfrom about 1.5 wt.% to just under 3wt.%. 590DX consistently shows 10-20˚F HDN activity advantage overNDXi over a wide range of feedsand conditions. Furthermore, thetest work has shown that the stabili-ty of 590DX is comparable to NDXiconsistent with the similarity in poresize distributions for the two cata-lysts.



Figure 3HDN Activity Comparison on a Variety of VGO Feeds

Time on Stream, hours

No

rmal

ized

Tem

per

atu

re,˚

F400 500 600 700 800 900 1000 1100 1200

NDXi 590DX

Light VGO Arab Medium VGO Yukong Heavy VGO

15F

20F

10F

As 590DX and other recent suc-cesses demonstrate, AdvancedRefining Technologies has devel-oped high performance technolo-gies aimed at helping refiners meetthe challenges presented by cleanfuels. This has been accomplishedin a few short years by capitalizingon the extensive material scienceand catalyst knowledge encom-passed by combining GraceDavison and Chevron. 590DX ismerely the latest catalyst resultingfrom the dedicated effort to offer thebest technology for refining today.

References

1. Krenzke, Dave; Vislocky, Jim.Hydrocarbon Engineering (2007), 12(11), 57-58

Cru

de

Tow

er

Vacu

um

Tow

er

ATTM Series

ATTM SeriesDXTM Series

ATTM SeriesDXTM SeriesICR Series

GR® SeriesLSTM SeriesHSLSTM Series

ICR Series

HOP® Series

StARTTM

CatalystSystem

SmARTCatalystSystem®

ApARTTM

CatalystSystem

Coker Naphtha

Naphtha

Kerosene

& Jet

Diesel

AT Series

DX Series

AT, DX Series

FCC Pretreat

Fixed Bed Resid

Fixed Bed Resid

Ebullating BedResid for LC-Finingand H-Oil® processes

Hydrocracker

Pretreat

AdvancedRefining

TechnologiesProduct Overview

he refining industry is onceagain going through the cycli-cal challenge of maximizing

margins, and with that, efficient bot-tom of the barrel upgrading using awide range of opportunity crudescontinues to be the focus. The Residhydrocracking (RHC) refiner, an ebul-lating bed resid hydrocrackingprocess, has an advantage wheresuch a wide variety of crudes can beprocessed allowing upgrading theresid to almost saleable distillates,very good quality FCC/HC feed VGO,and low sulfur fuel oil. However, pro-cessing such opportunity crudes hasits challenges, and ART has devel-oped and commercialized its latest EBResid hydrocracking catalyst technol-ogy to help in achieving that goal suc-cessfully and economically.

ART’s catalyst development effortswere directed after the followingneeds from the RHC operator’s:

• Same or higher resid conver-sion at reduced organic sedi-mentation to allow higher on-stream factor with opportunitycrudes.

• Improve quality (sulfur) ofupgraded products and sta-bility of HT resid product.

• Higher HDCCR conversion(for bottoms going to Cokerfeed).

• Higher API on total convertedproducts(synthetic crude pro-duction)

• Improve catalyst usage eco-nomics ($ cat/bbl feed) on theRHC.

ART’s Latest Catalyst Technologyfor EB Resid Hydrocracking

Balbir LakhanpalMarket Segment DirectorWorldwide Ebullating BedResid Catalysts

Darryl Klein, Ph.D.

Pak Leung, Ph.D.Senior Research Engineer

Nan Cheung, Ph.D.Senior Research Engineer

Pietro GrecoSenior Research Engineer

Ashok MonteiroTechnical Service Engineer

ADVANCED REFININGTECHNOLOGIES

T

BP Texas City - RHU

Courtesy BP Texas City



Organic sediment formation in theRHC is a key factor of operabilityand on-stream factor for the RHCrefiner, and is very dependent onthe characteristics of the resid,which is a function of the crudesource. ART, in close co-operationwith its joint venture partnerChevron, has done considerablework in defining the characteristicsof the resid and its impact on thesediment formation in the RHC,which has allowed the developmentof the its new RHC catalysts.

Three different resid feeds, A, Band C were identified and propri-etary techniques were used tocharacterize beyond the conven-tional SARA (Saturates, Aromatics,Resins and Asphaltenes) analysis.The asphaltenes were further bro-ken down to “good” and “bad”asphaltenes from Sediment forma-tion standpoint in the RHC process.As shown in Figure 1, even thoughthe asphaltenes content of thesefeeds was not too different, furthercharacterization showed large dif-ferences in the ratio of good to badasphaltenes, with Feed A being hav-ing the lowest ratio of good/badasphaltenes. The feed reactivityusing from pilot plant tests, Figure 2,confirmed that Feed A with the low-est good/bad asphaltenes ratio, orhighest feed difficulty factor, had thehighest organic sediment formationper unit resid Conversion (Sediment(ppm)/Resid Conversion (%) ratio),with all other parameters being con-stant.

Research efforts were then direct-ed, keeping in mind the above listedgoals, to develop RHC catalysts thatwould allow the lowest Sed-iment/Resid Conversion ratio.

After the very successful and wideacceptance commercially of the LS(Low Sediment) technology plat-form in 2004, ART’s latest develop-ment for RHC catalysts is theHSLSTM (High Stability LowSediment) technology platform.

Figure 1Feed Composition Variability – Advanced Characterization

Feed A

Feed B Feed C

Medium

Low

High

AromaticsAsphaltenes

Saturates

Resins

Aromatics Asphaltenes

Saturates

Resins

AromaticsAsphaltenes

Saturates

Resins

Good Asphaltenes

Figure 2Feed Reactivity vs. Sediment / Resid Conversion

Relationship

V.R

.Fee

d-

Ch

arac

teri

zati

on

“Dif

ficu

lty

Fac

tor”

FEED A

Sed

.(H

FT

)/R

.Co

nve

rsio

nR

atio

FEED B FEED C

<<<< Difficult Feed >>>> High Sed/Conv. Ratio

<<<< Easier Feed >>>> Low Sed/Conv. Ratio

Figure 3Catalyst Composition and Manufacturing Process

Alumina

the primarey (or sole) componentof the catalyst support

consists of ~30 angstromcrystallites agglomerated intomicron sized chunks

the basic building block for thecatalyst characteristics presentin the final catalyst

RHC Hydroprocessing CatalystChemical Composition

Metals

active components aremetal sulfides deposited onpore walls of the support

catalytic performanceaffected by the amountdispersion and distribution of themetals

Sub-Micron-sizedAlumina Particles

Micron-sizedAlumina Agglomerate

HydroprocessingCatalyst

Alumina & “Additives”

Process of Manufacture

Metals

The HSLSTM technology incorpo-rates a novel base, along with anadvanced and special processtechnology for efficient metalsimpregnation (Figure 3). The propri-etary alumina, with very specificpore size distribution (Figure 4), andthe process technology allows effi-cient use of the active metals.

Extensive pilot plant data, usingART’s standard feed, for the HSLSTM

technology showed higher stability,as measured by the resid conver-sion coefficient, and higher residconversion as compared to a rangeof previous catalyst technologies(Figure 5). For the three feeds test-ed, namely A, B, and C, the HSLSTM

technology exhibited higher HDM(Figure 6), higher MCR removal(Figure 7), and slightly higher sulfurremoval (Figure 8).

The sediment suppression ability ofthe HSLSTM technology, in Figure 9,for the three different feeds, showedthe degree of benefits that can beachieved for the broad range ofthese feed stocks. The pilot tests,and the advanced feed characteriza-tion, confirms the huge benefit(~40% reduction) in the applicationof the HSLSTM technology for Feed A(having a low good/bad asphaltenesratio), very good sediment suppres-sion (15-20%) for Feed B(mediumgood/bad asphaltenes ratio), andsmall benefit for Feed C(highgood/bad asphaltenes ratio).Sediment/Resid Conversion ratioreduction of 50%, 20% and 9% wasobtained using the HSLSTM catalysttechnology, Figure 10, for Feed A,Band C respectively.

The HSLSTM catalyst technology hasbeen use commercially very suc-cessfully in several RHC units since2008, with the undermentioned mul-tiple benefits:

• Lower Sediment formation(7-20%), allowing reducedfrequency of clean out ofdownstream equipment –higher on-stream factor andlower maintenance costs. In

Figure 4Catalyst Pore Structure

Mesopores

Macropores

Pore Size Distribution

Pore Diameter, Å

Pore size is a key in designand behavior of resid catalyst

Structures are carefullyformed and controlled inmanufacture

Determined by complexcharacteristics

Characteristics of aluminapowder

Incorporation of additives

Treatment after extrusion

Figure 5HSLSTM Offers High Stability

Act

ivit

yC

oef

fici

ent

(res

idco

nve

rsio

n)

Catalyst Age

Previous Catalysts HSLSTM Catalyst Technology

HSLSTM Catalyst TechnologyLower deactivation rate & higher stability

Previous Catalyst Technology (average rate)

High Stability - PP Data for HSLSTM

Figure 6High HDM Activity (High Metals Uptake Capacity)

for the HSLSTM Technology

Dem

etal

lati

on

Rat

e

Catalyst Age

Previous Catalysts Novel “HSLSTM Catalyst Technology”

Higher HDM for HSLSTM (3-7%)

PP Data - Hydro-Demetallation (Ni)

Feed A

Feed B

Feed C



Figure 7Higher Con Carbon Removal with HSLSTM

HD

MC

RR

ate

Catalyst Age

Previous Catalysts Technologies HSLSTM Technology

PP Data - HDMCR (Con Carbon)

Feed A

Feed B

Feed C

2 - 4% Higher MCRremovalwith HSLSTM

Figure 8HSLSTM has slightly higher HDS Activity

HD

SR

ate

Catalyst Age

Previous Catalyst HSLSTM Technology

PP Data HDS

Feed A

Feed B

Feed C

1 -3% Higher HDSwith HSLSTM

Figure 9HSLSTM Technology Platform - Sediment Suppression

Sed

imen

t(H

FT

)

Resid Conversion %

Previous Catalyst Novel “HSLSTM Catalyst Technology”

Sediment vs. Resid Conversion - Pilot Plant Data (Commercial Points)

Feed A

Feed B

Feed C

~40%Lower Sediment

2 - 3%Higher Conversion

Commercial Data

some cases this has allowedhigher Resid Conversionand/or flexibility of moreopportunity crude process-ing.

• Higher MCR removal – betterCoker feed quality

• Improved HDS of the distillateand unconverted resid.

• Significant reduction (5-15%)in fresh catalyst usage(specif-ic) rates

• Higher HDM – more value formetals recovery on spentcatalyst

Figure 10Feed Type vs. Catalyst Technolgy - Maximum Resid Conversion

Pilot Plant Data

Sedi

men

tatio

n/R

Con

v.R

atio

Sediment Suppression per unit Resid Conversionwith HSLS Catalyst Technology

FEED A FEED B FEED C

HIGH

LOW

~ 20%

~ 9%

~ 50%

Previous Tech

HSLSTM TechHH

PP

Additional test work with other Residfeedstock’s and commercial trials arealso planned.

The HSLSTM technology platform offersnew opportunities to the RHC refiner asan effective and efficient catalyst forthe bottom of the barrel upgrading inEbullating Bed Resid Hydrocracking.

References

1. PTQ. Autumn 2004, Upgrading HeavyOils with New Catalyst Technology.Balbir Lakhanpal, Darryl Klein, Pak Leung,Advanced Refining Technologies LLCBruno Tombolesi, Grace Davison-EuropeJózef Kubiak, Polski Koncern Naftowy SA



What are the challenges and concerns with hydroprocessing biodiesel such as palm oil, vegetable oil or ani-mal fats? HT Question #1

Brian WatkinsAdvanced Refining Technologies

Taking a detailed look at the compounds found in typical renewable oils shows that these oils could be treated asclassic petroleum based compounds. ART analyzed different renewable sources of fuels in order to better under-stand the possible chemistry that would occur if they were processed in a conventional hydrotreater. Bio-basedsources of oils can be of significant value when incorporated into the ULS diesel pool due to the low contaminantconcentrations and high cetane number of the resulting products.

The major saturated and unsaturated fatty acids found in these oils can consist of materials such as palmitic acid(C16:0), linolenic acid (C18:3), linoleic acid (C18:2), oleic acid (C18:1), eicosenoic (C20:1) and erucic acids (C22:1)in varying percentages. In the unbroken, unprocessed form, the triglyceride molecules are significantly outside thediesel pool range as they have molecular weights of 700 or greater, while the typical diesel pool has a molecularweight of less than 400 and these triglyceride molecules cannot be blended into the diesel pool at the levels requiredto meet renewable fuel standards. This requires conversion of the triglyceride in the hydrotreater in order for it to beused. Since these renewable feeds are derived from a biological source, they also contain a high concentration ofoxygen that is entirely dependent on the length and degree of saturation of the fatty acid chains. This quantity ofoxygen is important, as under normal hydrotreating conditions the oxygen will react with the hydrogen to form water.This water, if generated in a significant enough quantity due to high percentages of oxygen in the hydrotreating feed-stock, may cause problems such as weakening the catalyst support or redistribution of the active metals and loss ofsurface area. Another concern is that these renewable feed sources can include various contaminants. An analysisof several different biofeed sources has indicated the presence of contaminants such as sodium, calcium and phos-phorus. Use of GRACE's adsorbents and other specialty catalysts these contaminants are able to be controlled.

Through the once hydrotreated however, these n-paraffins can be of significant value for ULSD as they have typicalcetane numbers ranging from 95 to 110 which can provide a significant boost for those refiners processing feedswith lower cetane (i.e. FCC LCO’s) as the typical diesel hydrotreater has only a small effect on cetane with cetaneupgrade of about 2-4 numbers. The downside is that as the percentage of renewable feeds are placed into thehydrotreater, the resulting n-paraffins will increase the cloud point of the diesel which in various areas of the worldcan be problematic.

2009 NPRA Q & A Selected Answers

October 11-14, 2009

Omni Fort Worth Hotel

Fort Worth, Texas

N P R AQ A&

Using one of Advanced Refining Technologies’ high performance distillate hydrotreating catalysts, we have been ableto capitalize on renewable sources of fuel by bypassing the purchase of renewable products for blending at thepump and instead processing the raw materials through conventional hydrotreating equipment to produce a higherquality ULSD product. Additional information regarding the co-processing of these materials can be found in the2008 NPRA paper (AM-08-80) "New Opportunities for Co-Processing Renewable Feeds in Refinery Processes."

What are the experiences and plusses/minuses (cost /fouling /flexibility/ H2 partial pressure) with dual pro-cessing of coker naphtha with straight run diesel /kero streams in a single hydrotreater with downstream frac-tionation? HT Question #11

Dave KrenzkeAdvanced Refining Technologies

The driving force for co-processing coker naphtha and straight run diesel/kero is to simultaneously produce reformerfeed and ULSD/ULSK. In order to accomplish this, a number of issues need to be addressed:Expanded guard beds to prevent catalyst bed fouling and pressure drop increase

• Coker naphtha is highly olefinic and requires a bed of activity grading to prevent bed plugging from polymer-ization.

• Coker naphtha may also contain coke fines so additional particulate grading is required.• Coker naphtha usually contains Si from the antifoam agent used in the coker and depending on the crudesource may contain arsenic so a contaminant guard bed is required to protect the downstream hydrotreatingcatalysts.

• The expanded guard beds reduce the volume of active catalyst and consequently reduce cycle length.Decrease in hydrogen partial pressure and higher heat release

• The addition of coker naphtha results in greater feed vaporization and higher hydrogen consumption resultingin a lower hydrogen partial pressure and increased catalyst deactivation.

• The saturation of olefins releases significantly more heat than other hydrogenation reactions leading to largeexotherms. Since the EOR is usually determined by a maximum outlet temperature, this could result in a short-er cycle length.

Quality of reformer naphtha

• The downstream stripping/distillation will have an impact on the quality of the naphtha streams as any remain-ing H2S from the stripper bottoms will concentrate in the light naphtha.

• The sulfur content of the heavy naphtha may increase near the End Of Run (EOR) due to recombination. Toprotect the reformer, the EOR temperature may need to be lowered or a sulfur trap installed.

In conclusion, co-processing coker naphtha and straight run diesel/kero is feasible but may result in a cycle lengthpenalty and/or require additional equipment such as a sulfur sorber.

Does anyone bottom dump and water wash the reactor walls during catalyst change-out where nitrogen-blan-keting would otherwise be required? When using the water flood approach, we have experienced extendeddelays when dumping and reloading ULSD reactor vessels. What can be done to expedite this without com-promising safety? HT Question # 12

Woodrow ShiflettAdvanced Refining Technologies

At least one international major refiner typically wet dumps most all hydrotreater and hydrocracker reactors for safe-ty reasons. Owing to the long history of the practice with this refiner, the appropriate balance between expeditedchange-out timelines and safety was achieved some time ago.



What techniques are being used to shutdown and startup units without flaring?What equipment modifications have been made to eliminate flaring during shutdown/startup?HT Question #13

Geri D’AngeloAdvanced Refining Technologies

Flaring can be greatly reduced or totally eliminated by using the fuel gas system and purging via an amine scrubberin most applications. Another option is routing the overhead stripper and/or hydrogen purge from the separator gasto the refinery’s wet gas system. The wet gas systems normally run at a lower pressure so the volume left in the equip-ment is minimized and can then be routed to the flare.

Lines from high pressure separators and stripper tower overhead piping systems to fuel gas systems via an aminecontactors can be used to remove H2S.

The industry practice is to maintain H2S (hydrogen sulfide) presence when circulating H2 (hydrogen) at oper-ating temperature during a start-up. What experience do you have where activity was not significantly impact-ed as a result of high temperature operation without H2S presence? Please indicate amount of time in thiscondition. Is there any difference or concerns with heating up with N2 (nitrogen) instead of H2 in terms ofreduction? HT Question #15


The catalyst is in danger of being reduced during sulfiding when the atmosphere changes into H2 only instead ofH2/H2S at temperatures above 500˚F. If H2S is lost during the sulfiding it is imperative to reduce the temperaturesback down to below 400˚F until H2S can be re-established into the system and the sulfiding can be resumed.Keeping the temperature high in a H2 rich atmosphere is a favorable condition for metals reduction. The reducedmetals cannot be reactivated in situ so the result is lower than expected activity.

I’m aware of at least one sulfiding where a purge valve was left open. The purge valve was not "board operated" andwas forgotten about. The catalyst reached 550-600˚F in a H2 rich environment for an extended time, and was neverable to achieve the 500 ppm sulfur spec. The refiner had to quickly dump and reload another batch of catalyst beforethey could resume low sulfur diesel production.

Heating up in nitrogen poses no risk of catalyst metals reduction. There may be issues with gas circulation becauseof the higher molecular weight. Note, however, the hydrogen is necessary during a sulfiding.

After a catalyst loading, is it standard practice to flush the unit to cutter stock or slop until product is clear asopposed to re-circulating back to a feed tank or directly back to the unit charge? What are the concerns andrisks? HT Question #16

Gordon ChuAdvanced Refining Technologies

As Loaded

Reducedand SinteredLow Activity

DesiredConditionHighestActivity

NiOMoO3

NiSMoS2

NiMoO2

H2, H2S, 430 - 450˚F

(fast)

H2~500˚F

H2, no H2S

Sulfiding Chemistry

It is ART’s standard practice to flush the unit to cutter stock or slop until the product is clear before re-circulating itback to the unit charge. This step is to ensure to remove the catalyst fines from the catalyst. Otherwise, catalyst finescould get back into the catalyst beds causing excess pressure drops.

What are the preferred response options to different sizes of hydrotreater furnace tube leaks? Discuss differ-ent response options for large ruptures versus very small leaks. HT Question # 17


Slowly de-pressuring to downstream lower pressure H2 manifold or refinery fuel gas system for small controlled leaks.Most newer hydrotreaters are equipped with emergency pressure reduction systems that can rapidly dump a unit toflare system for evacuation during a major leak/rupture.

Typically silica has been associated with naphtha streams. More recently silica is being seen in heavy oilfeeds. What are refiners experiences with this issue? How does this impact catalyst life and what are thesolutions? HT Question # 18

Woodrow ShiflettAdvanced Refining Technologies

Silica, or silicon-containing compounds, in heavy oil feeds can arise from two general sources. Bitumen-derived syn-crudes, in addition to potentially containing some decomposition products from delayed coker sourced siliconantifoam, can in some cases contain exceptionally small particulate silica from the tar sand source. The second gen-eral source is comprised of upstream or pipeline additives that are used for various wellhead applications or pipelineapplications.

How do you deal with catalyst deactivation issues when both silica and arsenic are present in hydrotreaterfeed? HT Question #19

Charles OlsenAdvanced Refining Technologies

Feeds containing both silica and arsenic present a unique challenge to refiners because the contaminants poisonhydrotreating catalyst via different mechanisms. Silicon fragments in the feed are known to distribute uniformlythroughout the catalyst particle. They react with the alumina O-H groups forming a strong chemical bond with thealumina. Experience has shown that an effective catalyst for Si pick up has very high alumina surface area and porevolume which provide space to store the Si. ART offers AT724G for applications requiring a silica guard, and it hasbeen used with a variety of feeds from naphtha to VGO.

Arsenic, on the other hand, poisons the catalyst active metal sites. Arsenic in the feed reacts with nickel on the cat-alyst to form nickel arsenide, NiAs. Based on this stoichiometry, a nickel based arsenic trap can theoretically pick-upabout 1.28 wt.% As for each 1 wt.% Ni on the catalyst. The actual capacity will depend on process conditions (in par-ticular temperature) and the concentration of arsenic in the feed. ART offers several different catalysts for arsenicprotection including AT535, AT575 and AT580. The choice of catalyst depends on the feed and conditions of theparticular application.

In units with both Si and As, two catalysts are typically offered to handle the contaminants, one for silica and one forarsenic (i.e. AT724G and AT575). The amount of each is determined by the amount of Si and As in the feed, theLHSV and the desired cycle length. This approach has proven effective at protecting the main catalyst from Si andAs poisoning, but it can also decrease the volume of active catalyst since most of the guard catalysts are lower inactivity than the main catalyst. To alleviate this, Advanced Refining Technologies will be commercializing a new cat-alyst called AT734G. This catalyst has been specifically designed to provide a high capacity for both Si and As thuseliminating the need for two separate guard catalysts.


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The information presented herein is derived from our testing and experience. It is offered, free of charge, for your consideration, investigation andverification. Since operating conditions vary significantly, and since they are not under our control, we disclaim any and all warranties on the resultswhich might be obtained from the use of our products. You should make no assumption that all safety or environmental protection measures areindicated or that other measures may not be required.

Catalagram®, D-PrISM®, Grace®, Grace Davison®, GSR®, and SuRCA® are trademarks, registered in the United States and/or other countries, ofW. R. Grace & Co.-Conn. NEPTUNE™ is a trademark of W. R. Grace & Co.-Conn.

SmART Catalyst System®, ApART™, AT™, DX™ and StART™ are trademarks of Advanced Refining Technologies, LLC. ART® and ADVANCEDREFINING TECHNOLOGIES® are trademarks, registered in the United States and/or other countries, of Advanced Refining Technologies, LLC.

Chevron® and ICR are trademarks, registered in the United States and/or other countries, of Chevron Intellectual Property LLC. LC-FININGTM is atrademark of Chevron Intellectual Property LLC.

HOP is a trademark, registered in the United States and/or other countries, of Japan Energy Corporation licensed to Advanced Refining Technolo-gies, LLC and W. R. Grace & Co.-Conn. H-OIL® is a trademark, registered in the United States and/or other countries of Axens North America, Inc.

This trademark list has been compiled using available published information as of the publication date of this brochure and may not accuratelyreflect current trademark ownership. This brochure is an independent publication and is not affiliated with, nor has it been authorized, sponsored,or otherwise approved by any of the aforesaid companies.

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