The Catalyst Review April 2024 - 8

SPECIAL FEATURE
The characteristics of the FCC and steam
Table 1. FCC and steam cracking comparison. Source: Author
cracking units allows high yield of olefins
in the refining process without competition
for feedstocks. The FCC is a bottom of the
barrel conversion technology based on
carbon rejection that applies mainly gasoil
as feed stream whereas the steam cracking
process produces mainly ethylene through
thermal cracking of ethane and high
paraffinic naphtha.
The yield of propylene in the steam cracking units relies on the feedstock quality, being higher in units processing naphtha. In recent
years, some refiners are adopting the ethane as main feedstock due to its lower prices, this fact reduces the propylene offer from
steam crackers, raising the relevance of the propylene from FCC units to ensure the market supply. This fact has been the main driver
to the growth of propylene on-purpose technologies like propane dehydrogenation, methanol to olefins, and metathesis. Despite this
recent trend, the steam cracking units remain the main propylene source to the market with close to 48% of the market.
An example of refining configuration relying on FCC
and steam cracking units is presented in Figure 11. It
is interesting to note that a propane dehydrogenation
unit (PDH) in applied to improve the olefins yield.
Considering the recent trend of reduction in
transportation fuels demand, followed by the growth of
the petrochemicals market, makes the synergy between
FCC and steam cracking units an attractive way to
maximize the petrochemicals production in the refining
hardware.
As aforementioned, in light of current trend of
reduction in transportation fuels demand at the
global level, the capacity of maximum added value to
crude oil can be a competitive differential to refiners.
Due to the high capital investment needed for the
implementation that allows the conventional refinery
to achieve the maximization of chemicals, capital
efficiency becomes another extremely important factor
in the current competitive scenario, as well as the
operational flexibility related to the processed crude oil
slate. In the refining scheme presented in Figure 11, it
is important to note that the propane dehydrogenation
unit is applied to improve the yield of propylene, as
well as contribute to the hydrogen balance of the
refinery, while the residual streams are fed to the
steam cracking unit, leading to even more light olefins
production.
Figure 11. Integrated refining scheme based on FCC and steam cracking units.
Source: UOP 2019.
The Synergy of Steam Cracking and FCC Technologies in the Crude Oil to Chemicals Strategy
Due to the increasing market and higher added value, as well as the trend of reduction in transportation fuels demand, some refiners
and technology developers have dedicated their efforts to develop crude to chemicals refining assets. One of the big players that
has been invested in this alternative is the Saudi Aramco Company. The concept is based on the direct conversion of crude oil to
petrochemical intermediates as presented in Figure 12.
The process presented in Figure 12 is based on the quality of the crude oil and deep conversion technologies like High Severity or
petrochemical FCC units and deep hydrocracking technologies. In this case, it is interesting to note the added value to the processed
crude through the synergy of FCC and naphtha steam cracking units.
8
The Catalyst Review
April 2024

The Catalyst Review April 2024

Table of Contents for the Digital Edition of The Catalyst Review April 2024