Hydrocarbon Processing - August 2022 - 29

Special Focus Refining Technology
R. B. SINGH, Bechtel India
Evaluate options for decarbonizing
petroleum refineries
The energy transition requires rebuilding
the energy supply infrastructure
for a lower-carbon economy and renewable
energy generation for industry and
transportation that run more on electricity
and hydrogen (H2
) and less on fossil
fuels and provide a circular path for consumer
plastics. The growth in global oil
demand is predicted to end within 10 yr,
but it is still too early to foresee a rapid
decline in that demand.
Refiners are strategizing to align with
a low-carbon future. Moving from transport
fuels to petrochemical feedstocks,
producing renewable fuels and sourcing
low-carbon H2
are emerging as possible
options. However, uncertainty remains
around demand forecasts and potential
regulatory framework. Governments,
technology providers, refinery owners
and engineering companies will all play
a role in selecting and implementing the
most efficient and least-disruptive pathways
to a low-carbon future. One thing is
certain: this transition will be gradual and
require operating refineries to align product
slate with demand and reduce their
direct carbon dioxide (CO2
) emissions.
Although the vast majority (85%-90%)
of carbon emissions in the petroleum fuel
cycle occur during final consumption of
the petroleum products, refineries remain
a substantial source. This article estimates
the CO2
emissions from refineries and the
impact that factors such as crude quality,
configuration, electricity source, etc., have
on these emissions estimates. Options for
reducing emissions from major sources
are also evaluated.
Refinery CO2
emissions. Petroleum
refining products are an essential part of
the world economy, providing energy as
well as other high-value products. The refining
process involves separating, crackFIG.
1. Simplified flowchart of refining processes and product flows.2
Hydrocarbon Processing | AUGUST 2022 29
ing, restructuring, treating and blending
hydrocarbon molecules to generate petroleum
products. FIG. 1 shows a simplified,
typical overall refining process. The
specific processes implemented will vary
from refinery to refinery and depend
upon the refinery's capacity, feedstock
and specific product slate.
Each refinery has unique features,
which makes finding a global unified
model to represent all of them difficult.
This is even more true when it comes to
estimating CO2
emissions from a refinery,
allocating the emissions to products
to determine the impact on fuel carbon
intensity, and developing strategies for
CO2
reduction. However, it is possible to
represent operating refineries in a few scenarios
by grouping the common variables
impacting CO2
emissions. While this will
not have the granularity of an individual
refinery model, it does provide useful insights
into potential CO2
reduction strategies,
target emissions and achievable
reductions. The Petroleum Refinery Lifecycle
Evaluation Model (PRELIM) deModelling
methodology. PRELIM
employs a system-level approach and refinery
linear modelling methods. This
veloped at the University of Calgary and
freely available for download1
is used here
to estimate CO2 emissions for a range of
refinery configurations, feedstocks, upstream
emissions and energy sources.
PRELIM was developed to offer a free,
flexible, transparent and open-source tool
that captures the impact of crude oil quality
and refinery configuration on energy
use and the environmental impacts associated
with refining crude oils.
The estimates from PRELIM are analyzed
for CO2
reduction strategies. Techfrom
refinery heatnically
feasible technologies are proposed
for reducing CO2
ing, steam methane reformer (SMR) H2
units utilizing natural gas (NG) feedstock
and fluidized catalytic cracking (FCC).
For simplicity, global warming potential
(GWP) in terms of CO2
(CO2
equivalent
e) is presented as CO2
-in a refinery,
that is the major component.
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