HR 500 serieswith ACE™ technologyAxens’ advanced catalytic engineering (ACE) technology has been

applied to the manufacture of a new series of hydrotreating catalytic

materials – the HR 500 series of CoMo, CoMo-Ni, NiMo and

hydrocracking pretreatment catalysts. Comprehensive adsorption

modeling studies coupled with detailed feedstock and effluent

analyses have led to the adaptation of manufacturing facilities to

enable sub-micron level control in hydrotreating catalyst production.

The ACE concept has afforded a new class of dual-activity products

with significantly enhanced desulfurization activity and, as a bonus,

enhanced denitrogenation activity.

Axens’ HR 500 series catalysts, with ACE technology, exhibit

a powerful attraction for organosulfur compounds. Used in

combination with EquiFlow™ reactor internals and Catapac™

dense-loading technology, HR 500 series catalysts provide strong

performance improvements for long-lasting, ultra-low-sulfur diesel

(ULSD) production and vacuum gasoil (VGO) hydrotreatment.

Our advanced catalytic engineering

has powerful attraction

Axens Axens North America, Inc.Procatalyse Catalysts & Adsorbents Procatalyse Catalysts & Adsorbents89 bd Franklin Roosevelt – BP 50802 1800 St James Place, Suite 50092508 Rueil-Malmaison, France Houston, Texas 77056-4199, USATel: +33 1 47 14 21 00 Tel: +1 713 840 1133Fax: +33 1 47 51 87 95 Fax: +1 713 840 8375

www.axens.net

Advanced catalytic engineering (ACE) technology

Dual-activity hydrotreating catalysts

HR 500 series catalysts

Stepping up HDS activityACE technology provides a major step-upin hydrodesulfurization (HDS) activity thatenables the attainment of ULSD dieselspecifications, whether they are less than50-, 15- or 10-ppm product sulfurobjectives. Catalyst evaluations have beencarried out at 7-ppm product dieselspecification and below, i.e., ULSD7, toensure compliance with the most severeconstraints. In many cases, revampingfrom current sulfur targets to ULSD7

can be achieved through the addition ofsupplementary catalyst volume to currentoperations with equipment revamping.

The HDS activity gain with ACEtechnology is indicated in Figure 1.Compared with previous-generationcatalysts, the operating temperaturereduction for diesel desulfurization, as a function of product sulfur, improvessubstantially. The maximum activity gainsare obtained at the lowest product sulfurspecifications. The tougher the job, thebetter the HR 500 series performs.

Dual activity boosts HDSNot only does ACE technology directlyboost the HDS activity of HR 500 seriescatalysts, it also simultaneously providesimproved hydrodenitrogenation (HDN)activity. Organonitrogen compounds are

known to inhibit the adsorption of sulfur

compounds, thereby reducing HDS activity.

The superior HDN activity offered by these

engineered materials provides an added

boost in HDS activity by liberating active

sites. A schematic representation of the

dual-activity function is shown in Figure 2.

The elimination of nitrogen-containing

inhibitors becomes particularly important for

ULSD applications where the objective is to

eliminate trace amounts of sulfur. Nitrogen

inhibition is an important consideration at

low sulfur target levels because the nitrogen

content can be substantially higher than the

sulfur content. The dual-activity function of

the ACE series provides an added, indirect

boost in HDS activity by freeing the sites

needed to remove unwanted sulfur species.

Material engineering on the small scale

Mixed sites involving at least one Mo

atom in close proximity to one promoter

atom (Co or Ni) are required to generate

the synergy effects needed to reach high

HDS turnover frequencies. Engineering

the shape of the mixed crystallites has

produced new materials that provide

enhanced activity per volume. ACE

technology has enabled the best

utilization of each gram of molybdenum.

Effl

uent

sul

fur

cont

ent,

ppm

WABT

50

40

30

20

HR 500 series Previous series

107

0

Boost inHDN activity

ACE

Boost inHDS activity

Figure 2: The dual activityof ACE technology.

Figure 1: HR 500 catalysts step up HDSactivity. The gain in relative volumeactivity is indicated.

Dual-activity

Modeling simulations at the atomic levelhave provided insights into the superiorHDS activity of the ACE materials. Thecommercial catalysts contain crystalliteshapes of active metals with sites that are particularly suited to the adsorption of organonitrogen species. An atomicrepresentation of the two crystallitestructures, with and without ACE-typeactive sites, is shown in Figure 3. Thecrystallite sizes shown are provided only for illustration and do not represent anaccurate size comparison.

Strong, stable and simple Cycle length

HR 500 series catalysts have the keycombination of high initial activity and lowdeactivation rate that enables them toachieve superior cycle lengths. Since cyclelengths are not just a matter of initialactivity, the new series builds on the samemanufacturing principles that provided highlevels of stability to previous HR products.

The results of a stability test performedover more than 1700 hours under ULSD7

conditions are shown in Figure 4. This testwas based on a typical straight run/cracked-stock feed mixture at moderatepressure. The effluent sulfur content wasmaintained at 7 ppm throughout the test.A comparison of the weighted average bed

WA

BT

300 1000 1700

Time, hr

HR 426

New HR 526

Figure 4: Change in WABT over time forCoMo catalysts under ULSD operation.

Figure 3: An atomic representation ofthe two crystallite structures, with(top) and without (bottom) ACE-typeactive sites.

y hydrotreating catalysts

temperature (WABT) over time for the HR

526 catalyst (CoMo) and the previous-

generation product shows a major activity

gain for HR 526 and retention of the same

benchmark stability.

Stability testing under various VGO service

conditions, including VGO HDS, mild- and

full-conversion hydrocracking pretreatment

confirms the results obtained under ULSD7

operation. In all cases, ACE technology

materials outperformed all the other

catalysts tested on an activity per volume

basis and in expected cycle length.

Easy to use

ACE catalysts can be loaded directly

into commercial units without nitrogen

blanketing. The mechanically tough HR

500 products rely on conventional sulfiding

procedures and are readily regenerated

for reuse. They require no special post-

regeneration chemical treatment.

For most units, dense loading reactors

with Catapac technology afford the

maximum catalyst volume activity. In

addition, EquiFlow reactor internals ensure

optimized flow distribution for maximum

catalyst effectiveness. The combination of

HR 500 series catalysts, dense loading and

EquiFlow internals can easily lead to a

reduction in WABT of 10 to 20ºC for

ULSD applications.

Mo Co (Ni) Sulfur

ACE sites Conventional sites

Optimizing hydrotreating costs

with ACE catalysts

In the catalyst replacement market,

the outstanding HDS activity and dual-

activity boost provided by the new

HR 500 series ACE technology materials

make it possible to operate at lower

temperatures and obtain longer cycles

for a given HDS performance and

equivalent hydrogen requirements.

Alternatively, it is typically possible to

include additional, lower-cost refractory

cracked stocks in the feed.

For revamping and debottlenecking

projects when additional reactor volume

is required, the HR 500 products provide

the activity necessary for employing

smaller reactors, thereby saving on

capital costs. For grassroots projects,

ACE technology products make it

possible to design units to operate at

lower pressure.

ULSD and conventional diesel applications

HR 526 (CoMo) and HR 548 (NiMo)

catalysts are ideal for diesel

hydroprocessing objectives. In some

cases, the association of both products

is advantageous. The ACE family also

includes the new HR 568 (CoMo-Ni)

catalyst that exhibits impressive

performance on refractory feedstocks

while limiting hydrogen consumption.

This CoMo catalyst is provided with

promoted hydrogenation activity

through the addition of some nickel,

which is advantageous for the

treatment of refractory stocks.

VGO applications

The fourth ACE catalyst in the 500

series, HRK 558, is specifically developed

for hydrocracking pretreatment

applications. HRK 558 employs similar

manufacturing principles to those that

made the previous NiMo product so

successful in HDN service. The porosity

of HRK 558 is ideally suited for VGO

feeds. The ACE sites provide ultra-high

denitrogenation rates upstream of

zeolite and amorphous hydrocracking

catalysts. HRK 558 shows exceptional

pre-conversion activity and also enables

the production of outstanding quality

lube oil bases from hydrocracked

residue. For VGO applications where

limited conversion objectives apply, as in

mild hydrocracking, HR 548 is ideal for

low-to-medium-severity feeds.

For fluid catalytic cracking hydrotreaters

with VGO-based feeds, HR 568 is well

adapted for many applications,

depending on the refractory nature of

the feedstock, sulfur objectives andhydrogen availability.

Naphtha applications

For mild service needs, such askerosene/jet fuel hydrotreating andsweetening, naphtha reformingpretreaters, and second-stage pyrolysisgasoline desulfurization, HR 506 is theproduct of choice.

Advanced catalytic engineeringhas powerful attractionWhen sulfur elimination is the criticalobjective, our hydrotreating technologytoolbox has the competitive edge forcost-effective performance improvement.Axens supplies a complete set ofbenchmark sulfur-removal technologies:

■ ACE technology engineered materials:HR 506, HR 526, HR 548, HR 568 and HRK 558

■ ACT top-bed grading materials

■ EquiFlow reactor internals

■ Catapac dense-loading technology.