Chemical Engineering November 2011 - 32

Cover Story
Feature Report
Part 1
Energy Benchmarking
A method incorporating
energy optimization
and its viability
is exemplified in
a petrochemical
application
Farbod Rikhtegar
IFCO Co.
I
n today's climate of increased energy
prices and tightening environmental
emissions requirements,
petrochemicals producers
around the world are continuing to
focus on optimizing energy consumption
at their facilities. Over the past
few years, while energy prices have
been increasing, petroleum refiners
and chemicals producers have made
progress toward
improved,
overall
energy performance by implementing
energy efficiency programs. In general,
these programs and initiatives
have focused on the relatively easy
energy efficiency targets, such as furnace
O2 levels and minimizing slowrolling
steam turbines.
While these initiatives are an important
step, a strategic approach is
now required that focuses on implementing
and sustaining the energy
optimization program. After all, Energy
is the petrochemical's largest
single operating cost.
Recently, the author's employer used
its continuous energy-improvement
methodology to help the Iranian National
Petroleum Co. achieve realistic
energy-optimization targets. This article
outlines the methodology required
for a successful strategic approach
to energy optimization, and includes
specific case studies to illustrate the
complexity of the challenge.
Methodology
There are two separate activities that
link together to form the benchmarking
program: the strategic energy review
(SER) and the energy management
system (EMS).
The SER is carried-out first, and it
incorporates a number of activities,
ranging from benchmarking to gap
analysis,
metric identification, and
" road map " development. The purpose
of the SER is to fully understand the
energy situation at the operating site
to suggest the best-suited strategic
plan and identify all operational and
investment improvement opportunities.
A tailor-made energy management
system follows the SER. The
EMS incorporates improved bestpractice
documentation, enhanced organizational
requirements and monitoring
tools. This enables the operator
to implement and sustain the energy
optimization ideas from the SER.
32 CHEMICAL ENGINEERING WWW.CHE.COM NOVEMBER 2011
Benchmarking
The first element of the SER is benchmarking.
There are many different
ways of benchmarking a site. Best
technology (BT) methodology incorporates
targets, which are developed
through process simulations, proven
designs and correlations based on the
variation of key parameters affecting
energy consumption. One of the keys
to successful benchmarking is to ensure
that the base case data that are
used are valid and reconciled. For end
users, the BT method chose two base
case months with known swings in
operation: A typical winter operation,
and a typical summer operation. The
balances required for the benchmarking
are fuel balances (production and
consumption), steam balances and
power balance.
Best technology basics. The simulated
best design features all economically
justifiable options and incorpo200
250
300
100
150
50
Efficiency
sequence
FIGURE 1. This graph shows the comparison of the best technology (BT) index for
a number of petrochemical sites, both before and after implementing recommended
energy-saving measures
Unit
TABLE 1. PLANT'S MEASURED ENERGY CONSUMPTION
Fuel
Net steam consumption
import
ton/h
Aromatics 5.3
Olefins
2.6
HP
ton/h
82.0
173.0
MP
ton/h
0.0
0.0
LP
ton/h
0.0
0.0
Power
import
MW
5.5
6.4
Before optimization
After optimization
BT efficiency, %
http://WWW.CHE.COM
Chemical Engineering November 2011

Table of Contents for the Digital Edition of Chemical Engineering November 2011
