Organic Process Research & Development 2009, 13, 965–969
Safety Advantages of On-Site Microprocesses
Fatemeh Ebrahimi, Eero Kolehmainen,* and Ilkka Turunen
Lappeenranta UniVersity of Technology, Department of Chemical Technology, P.O. Box 20, FIN-53851 Lappeenranta, Finland
Abstract:
acid and hydrogen peroxide have been reported.6,7 Also, on-
site microreactor systems have been applied to the production
of hydrogen.
Usually large-scale capacities are preferred in process industry
because of the economics of scale. However, small capacities bring
along several other advantages, which are emphasized especially
in on-site production. By producing on-site, the transportation of
dangerous chemicals can be avoided. Moreover, smaller on-site
production processes also mean a step towards inherently safer
technology. Microreactors represent a technology that efficiently
utilizes safety advantages resulting from small scale. These safety
advantages of microreactors in on-site production are studied in
this contribution. Production of peracetic acid is used as a test
case. This unstable and explosive chemical is used, e.g. in treatment
of municipal wastewater and pulp bleaching. This study is based
on comparison of a conventional batch process with the capacity
of 170 kg/h and an on-site continuous microprocess producing 10
kg/h peracetic acid. Preliminary design of these processes was
carried out. Four different methods were used to analyze the safety
of the processes. It was found that the conventional methods for
analysis of process safety might not be reliable and adequate for
radically novel technology, such as microprocesses. This is under-
standable because the methods are partly based on experience,
which is very limited in the connection of totally novel technology.
8-10
Applying microreactors to on-site production should combine
the above-mentioned advantages and introduce new ones. This
report attempts to demonstrate the advantages by comparing a
conventional batch process and a continuous on-site micropro-
cess to produce peracetic acid. Peracetic acid is an unstable
substance because of thermal decomposition, and therefore,
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safety aspects in the production have to be emphasized. Safety
of the processes was studied by different safety evaluation
methods. Preliminary design of these processes was carried out
to enable the comparison.
In this study, four safety evaluation methods are applied:
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Reaction matrix, Dow’s Fire and Explosion Index, Inherent
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Safety Index, and Worst Case and Consequence Analysis.
These methods are applied at different stages of design. At
the preliminary design phase, the available information is
limited. At this stage, however, the influence of the decisions
is most important because they determine major features of the
process. The reaction matrix reveals the undesirable combination
of materials and is useful particularly early in the development
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of a new chemical processes. Dow’s Fire and Explosion Index
is a suitable safety analysis method for the predesign (conceptual
1
. Introduction
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Safety of microreactors is based on a small reaction volume,
design) stage. Inherent safety index can be applied at the R&D
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which leads to small inventory of dangerous chemicals. In
addition, the efficient heat transfer resulting from the high
surface area-to-volume ratio, improves temperature control and,
therefore, decreases the risk of run-away reactions. Thus, it is
also possible to use higher operating temperatures safely. This
increases the reaction rate and might lead to a smaller reaction
volume. Microreactors have been applied successfully to many
hazardous reactions such as fluorinations, chlorinations, oxida-
tions, and brominations. Sometimes those reactions have been
carried out at elevated temperature and pressure without safety
and process predesign stage. Worst case and consequence
analysis is a method to recognize the most harmful events and
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analyze their consequences.
(
6) Vineyard, M. K.; Moison, R. L.; Budde, F. E.; Walton, J. R.
Continuous process for on-site and on demand production of aqueous
peracetic acid. U.S. Patent 7,012,154, 2006.
(7) Brillas, E.; Alcaide, F.; Cabot, P. A. Electrochem. Acta 2002, 48, 331–
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40.
(
8) Patterkar, A. V.; Kothare, M. V.; Karnik, A. V.; Hatalis, M. K. IMRET
5, Strasbourg, France, May 27-30, 2001; Proceedings of the 5th
International Conference on Microreaction Technology; Springer-
Verlag: Berlin, 2001.
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problems.
On-site production decreases the transportation and storage
requirements of dangerous materials. This improves safety and
may also reduce costs. On-site applications to produce peracetic
(
9) Cristian; Mitchell, M.; Kenis, P. J. A. Lab. Chip 2006, 6, 1328–1337.
(
(
10) Cristian; Mitchell, M.; Kim, D. P.; Kenis, P. J. A. J. Catal. 2006,
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41, 235–242.
11) Swern, D. Organic Peroxides; Wiley Interscience: New York, 1970;
Vol. 1.
*
Corresponding author. Telephone: +358-5-6216128. Telefax: +358-5-
(12) McKetta, J. J.; Anthony, R. G.; McKetta, J. J.; Cunningham, W. A.
Encyclopedia of Chemical Processing and Design, 2002.
(13) Dow’s Fire & Explosion Index Hazard Classification Guide, 7th ed.,
AIChE Technical Manual; American Institute of Chemical Engineers:
New York, 1994.
(14) Heikkil a¨ , A. M. Inherent safety in process plant design, PhD Thesis;
Technical Research Centre of Finland, VTT publications 385: Espoo,
1999.
(15) Flynn, A. M.; Theodore, L. Health, Safety, and Accident Management
in the Chemical Process Industries: A Complete Compressed Domain
Approach; Chemical Industries, Vol. 86; CRC Press: Boca Raton, FL,
2001.
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212199. E-mail: Eero.Kolehmainen@lut.fi.
1) Ehrfeld, W.; Hessel, V.; L o¨ we, H. Microreactors: New Technology
for Modern Chemistry; Wiley-VCH: Weinheim, 2000.
2) Hessel, V.; Hardt, S.; L o¨ we H. Chemical Microprocess Engineering:
Fundamentals, Modelling and Reactions; Wiley-VCH: Weinheim,
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(
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3) L o¨ b, P.; L o¨ we, H.; Hessel, V. J. Fluorine Chem. 2004, 125, 1677–
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4) Veser, G. Chem. Eng. Sci. 2001, 56, 1265–1273.
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0.1021/op900079f CCC: $40.75 2009 American Chemical Society
Vol. 13, No. 5, 2009 / Organic Process Research & Development
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Published on Web 08/17/2009