Hydrocarbon Processing - May 2022 - 48

Digital Technology
Network
Fuel gas
TABLE 1. Optimization benefits for the three networks
Energy, $MM/yr
Hydrogen
Steam
Total
4.6
4.1
2.9
11.6
clear optimization opportunities to save
energy and reduce CO2
emissions, supCO2,
thousand tpy
19
18
12
49
porting widely adopted decarbonization
programs across the process industry.
Considering energy and CO2
reduction
benefits for the three networks,
TABLE 1 shows optimization achievements
for the 200,000-bpd European refinery
example used throughout this article. CO2
emissions reduction in this case represents
3.3% of the overall refinery emissions,
with a value of more than $4 MM/yr at the
current price for CO2
Note that the 49,000 tpy of CO2
in Europe of $90/t.
in column
three of TABLE 1 is approximately 25%
of the CO2
permits that the 200,000-bpd
FIG. 9. Fuel gas consumption before and after optimization. Source: G. Ruggeri, S. Chillemi,
J. C. Duarte and S. Dhaliwal, " Balancing steam network production and demand improves
power generation, " Aspentech OPTIMIZE 2015.
European refinery example would need
to buy every year. Additional benefits can
be obtained from process units, primarily
from capacity and yield increases. An increase
in yields generally results in additional
energy savings due to a reduction in
costly quality giveaway.
These results can be achieved by leveraging
recent APC and optimization
technology enhancements that enable
users to efficiently address problems that
were previously difficult to solve. These
enhancements include:
* Adaptive process control to
maintain ever-green models
* Full nonlinear control
* AI to identify models and build
inferred properties to cope
with different run modes
and nonlinearities
* Flexibility to change optimization
strategy rapidly
FIG. 10. Letdown before and after optimization. Source: G. Ruggeri, S. Chillemi, J. C. Duarte and
S. Dhaliwal, " Balancing steam network production and demand improves power generation, "
Aspentech OPTIMIZE 2015.
* Carbon monoxide (CO)
boiler load (if present)
* Other local steam production
equipment and medium-/
low-pressure streams to
the network
* Boiler combustion handles
* Flexibilities in header
pressure control
* Steam exchange streams.
Significant benefits can be achieved
(FIGS. 9 and 10). Both figures show a reduction
in fuel gas consumption and letdown
before and after optimization. Using
the same refinery example, savings of
$2.9 MM/yr can be achieved and up to
48 MAY 2022 | HydrocarbonProcessing.com
12,000 tpy of CO2
saved through steam
network optimization.
Takeaway. In these volatile times, recent
advancements in APC and optimization
technologies provide
strong options
for oil and gas and chemical companies
faced with the dual challenge of achieving
energy efficiency and reducing carbon
emissions. With no CAPEX investment
needed, these solutions can quickly
deliver significant process efficiency improvements
and a negative CO2
abatement
cost (i.e., a net profit).
Utilities networks in refineries, petrochemical
and chemical sites present
* Self-adapting dynamic
optimization for multi-unit
optimization of large envelopes.
NOTES
a Aspen DMC3™
b Aspen Deep Learning IQ
c Aspen GDOT™
STEFANO LODOLO is a Senior
Manager Solution Consultant
with Aspen Technology in Italy.
He works with customers
throughout Europe in APC and
other process optimization areas.
Mr. Lodolo manages the APC and
optimization consultants in Europe and drives
business development for major oil and gas
companies. He has 35 yr of APC field experience
in the refining, chemical and petrochemical industries.
Mr. Lodolo has successfully implemented more than
100 multivariable predictive control and other
optimization projects on a wide variety of
process units. He earned an MS in chemical
engineering from Bologna University, Italy.

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