Hydrocarbon Processing - May 2022 - 63

Catalysts
N. PONGBOOT, Global R&D, Samut Prakan, Thailand;
and T. UPIENPONG and W. KARUNKEYOON,
PTT Global Chemical, Rayong, Thailand
Hydroprocessing catalyst selection-Part 1: Planning
and selecting the catalyst evaluation method
Hydroprocessing catalysts are an essential
part of any refinery involved in the
treatment/conversion of most petroleum
fractions ranging from naphtha to residue
(FIG. 1). Hydrotreating catalysts help refiners
meet fuel regulations and enhance the
performance of downstream catalysts and
processes [e.g., naphtha reforming or fluid
catalytic cracking (FCC)] by removing
sulfur, nitrogen and metals from their feedstocks
as well as improving product properties
by hydrogen addition. Moreover,
hydrocracking catalysts further improve
refiners' profits by converting low-value
streams [e.g., vacuum gasoil (VGO)] into
high-value fuels and chemical feedstocks.
Therefore, selecting hydroprocessing catalysts
requires great care to ensure maximum
asset utilization and profitability.1
Part 1 of this article discusses pitfalls in
planning and selecting the catalyst evaluation
method and provides best practices
to guide refiners towards an optimal hydroprocessing
catalyst selection.
Planning and invitation to bid (ITB)
development. Ideally, refineries should
begin the catalyst selection process 18
mos-24 mos before the next catalyst
change-out to provide sufficient time for all
tasks involved. Typically, catalyst lead time
is 6 mos-12 mos, leaving the rest for planning,
evaluation and internal processing.2
As a general practice, refiners should
apply a multi-disciplinary approach to
agree on catalyst requirements (e.g., longer
run length or more difficult feedstocks).
Additionally, the focal point (usually a
unit process engineer) should incorporate
current operating issues such as high
reactor pressure drop or maldistribution
into the ITB so the catalyst supplier can
properly address the problems in the next
cycle. Most importantly, the economic
direction should be clear (e.g., naphtha or
middle distillates as preferred products).
Be realistic with feed qualities stated
in the ITB. While being conservative will
minimize the risks of not meeting the
intended cycle length, being too conservative
can also underutilize the existing
unit or even worsen unit performance in
some instances.
For example, if metal contents stated
in the ITB are too conservative, use the
worst-case scenario for every metal species.
This usually means the catalyst
supplier will propose a larger portion of
Sulfur plant
Sat and unsat
gas plants
Alkylation
Isomerization
Atmospheric
distillation
Naphtha HT
Naphtha
reforming
Gasoline HT
Crude oils
Desalter
Fluidized cat
cracking
Gas oil HT
Hydrocracking
Vacuum
distillation
Marine fuel oil
Heavy ends
blending
Solvent
deasphalting
Visbreaking
Coking
Asphalt
Lubricants
Greases
Waxes
Distillate HT
Distillate
blending
Kerosene
Jet fuels
Diesel
Heating oil
Gasoline
blending
Aviation gasoline
Motor gasoline
Solvents
Sulphur
LPGs
Coke
FIG. 1. In modern refineries, hydroprocessing improves the qualities and value of most
petroleum fractions (highlighted in yellow and pink blocks).
Hydrocarbon Processing | MAY 2022 63
Hydrocarbon Processing - May 2022

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