Energy optimization at a chemical industry enterprise. Case study - Perstorp AB

Abstract

Executive summary
Title: Energy optimization at a chemical industry enterprise
Case study - Perstorp AB
Authors: Sandra Leksell and Anna Parsdotter
Supervisors: Patrick Lauenburg, PhD, Dept. of Energy Sciences, Faculty of Engineering,
Lund University and Daniel Hansson, Technical Manager,
Perstorp Specialty Chemicals AB
Background: The industrial sector in Sweden consumed 152.4 TWh energy in 2010,
which represented 36% of Sweden's total energy that year. The chemical
industry accounted for 11.4 TWh (7.5%). Energy eciency measures
and improvements are given priority by enterprises today, due to
increasing energy prices and implemented energy policies. To reduce
the competitive threat caused by increasing energy prices, Swedish
companies have two options; either negotiate a lower energy price
from the energy companies or work internally with energy eciency
measures. Industries located in colder climates, having a temperature
dependent production, are additionally aected by increased energy
prices. Perstorp Specialty Chemicals initiated this master's thesis,
because they have experienced a variation in steam consumption at
their factories. They believed the reasons behind the variety were
that production rate aected the energy consumption, that a cold
outdoor temperature resulted in energy leakage and that the base
load was similar throughout time. Despite this, they have never performed
any thorough energy analysis that conrms to what extent
these factors aect the energy usage in the factories.
Objective: The objective of this master's thesis was to evaluate the energy consumption,
mainly steam usage, at the chemical industry Perstorp AB
and this was performed by developing statistical models and evaluating
the energy management at the enterprise.
Methodology: This master's thesis is divided in two parts, and several dierent
methods have been employed in both. The rst part is an Energy
usage analysis, which began by creating an overview of the production
site and factories. The overview was made after visits to the
factories and studies of theirs
ow charts. Finally the processes were
discussed with employees at Perstorp. Relevant and available energy
data were then assembled and evaluated. An energy audit, founded
on the energy data, for four polyol factories was performed, where
large energy consumers were identied. Later, the energy performance
of these factories was evaluated. The latter included a study
of which variables that aected the steam consumption, and it was
based on the statistical model multiple linear regression.
2
The second part, Evaluating Perstorp's energy management, began
with a literature study and an interview with a PhD-candidate at
Lund Faculty of Engineering. After this, interviews were performed
with employees at Perstorp to gain knowledge on how the energy
management was handled at the company. After the interviews, an
overview was made of the energy management and working methodology.
Energy eciency measures within the company and possible
improvements regarding their management were suggested.
Conclusion: The main conclusion from the Energy usage analysis, was that the
statistical method used, multiple linear regression, can only be applied
for some systems. The method is straightforward, proving a
correlation, in this case between steam usage and other variables.
If the system was complex, with re
ows, heat recovery, leakage or
other factors aecting the steam consumption, the modelling gave a
poor result. However, if the system is simpler, e.g. with a product
in
ow heat exchanged against the steam
ow, or heating of component,
where the steam consumption correlates to the temperature,
the method can be of great use. The models for two out of four
factories resulted in a better correlation. One of the factories with
poorer result was examined more carefully with diverting result for
the components. Some of the steam consumption should be correlated
towards the outdoor temperature instead of production rate,
when calculating the company's energy budget.
Regarding the second part; the energy management at Perstorp is
organized, although it can be improved. The impression the authors
got after nishing the interviews at Perstorp was that energy is an important
issue, though it is not prioritized from the company's board.
Furthermore, the Energy Coordinator believes that the level of ambition
can increase at the company. Nevertheless, Perstorp has some
good examples of well-practiced energy management: weekly discussion
regarding energy ratios, a follow up if the ratio is higher than
expected and an Energy Coordinator that wants to improve their
ambitions. Still, there are some elds within the energy management
at Perstorp that can be improved, most importantly creating
an Energy group, which can get a comprehensive view concerning energy
issues. Additionally, Perstorp can improve the follow-ups after
energy projects are implemented, create long-term energy goals and
make the sta aware of these and have better training for the sta.

• author: Leksell, Sandra and Pärsdotter, Anna
• supervisor: Patrick Lauenburg
• organization: Department of Energy Sciences
• year: 2013
• type: H1 - Master's Degree (One Year)
• subject: Technology and Engineering
• keywords: Energy efficiency, Process Industry, Steam consumption, Multiple linear regression, Energy management system, Perstorp AB
• publication/series: ISRN LUTMDN/TMHP--13/5269--SE
• report number: 5269
• ISSN: 0282-1990
• language: English
• id: 3633988
• date added to LUP: 2013-04-18 08:59:37
• date last changed: 2016-02-04 03:57:01