Hydrocarbon Processing - March 2022 - 41

Process
Optimization
J. WORRELL, M. CLEMENTS and S. ECHETO,
Filtration Technology Corporation, Houston, Texas
How hydroprocessing feed filtration system design
impacts process reliability and efficiency
Oil refining is an exceptionally complex
industry, with much of the inherent
complexity stemming from wide regional
variances in crude quality and composition,
plant capabilities and the types of
products produced. This creates the need
for a broad range of equipment, processes
and technologies, which can vary in quality,
performance and design.
When considering process filtration,
some refiners explore innovative solutions
for solids contaminant control,
while others simply elect to maintain the
status quo. Low-efficiency or undersized
filtration systems can lead to frequent
and prolonged process upsets, as well
as downtime due to equipment fouling,
repeated filter changeouts and/or higher
process-related operating costs. Additionally,
frequent filter changeouts result
in higher direct consumable costs, along
with indirect costs related to safety, labor,
inventory and disposal.
The most significant cost in substandard
filtration lies in potential damage
to the catalyst beds of hydrotreaters and
hydrocrackers. Many operators do not
fully realize the impact of inefficient or
insufficient filtration in these units, and
they simply view filtration as an insignificant
piece of equipment on a piping and
instrumentation diagram (P&ID). However,
insufficient filtration, specifically
the lack of particle removal efficiency, has
a substantial impact on operational reliability
and costs.
Hydrotreaters are units that use hydrogen
to remove impurities (such as sulfur)
from petroleum cuts (FIG. 1). Hydrocrackers
are units that use hydrogen for
the conversion of heavy cuts into lighter
fractions such as naphtha, kerosene and
FIG. 1. Hydrotreaters remove impurities, such as sulfur or nitrogen, and are designed for specific
operations. Hydrotreater catalysts are composed of a porous alumina support with a coating
of metallic sulfides and are approximately 0.0625 in. in diameter. Common applications include
gasoline, naphtha, kerosene and gasoils, as well as biofuels, which present a broader range of
applications and challenges.
Hydrocarbon Processing | MARCH 2022 41
gasoils (FIG. 2). Both types of reactors use
a fixed bed of catalysts (along with pressure,
temperature and hydrogen) to cause
the desired chemical reaction.
These units are the heart of the refinery
and are critical to downstream processes
and product specifications. Fixedbed
reactors are often set up in series and
are used for low-to-medium metal content
in feeds. These reactors have graded
beds and progress from hydrotreatment
to hydrocracking.
Hydroprocessing filtration. The purpose
of feed filter
filtration for both
hydrocrackers and hydrotreaters is to
prevent fouling of the catalyst bed. Historically,
filter designs vary because the
quality and characteristics of crude oil
differ greatly by region and classification.
For example, the sulfur content in
sweet light crude is generally 0%-0.5% of
weight, while in lower-quality heavy sour
crude, it can be upwards of 5%.
This is significant because in the next
20 yr-30 yr, the market expects to witness
a growing movement toward lower-quality
crudes, as well as toward biosourced
feedstocks from plant-based and
animal-based oils. These changes will
result in completely different sets of filtration
challenges, and these trends may
also be accompanied by stricter environmental
specifications-all of which place
an increased demand on catalyst bed protection.
Nevertheless,
protecting the catalyst
bed by providing reliable and predictable
effluent fluid quality is the primary
goal of any properly designed filtration

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