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Industrial Safety - Home
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- Flammability limits
A possible method to avoid explosions from occurring inside
industrial process plants in which mixtures of a combustible gas
and air are present is working outside the flammable range of these
mixtures. To this end, the flammability limits must be known at the
process conditions. There are, however, limited flammability limit
data at elevated pressures and temperatures. This is the impetus
for this research, the aim of which it is to analyse the dependence
of the flammability limits on pressure and temperature.
A coherent theory of the influence of pressure and temperature on
flame propagation and extinction is being developed, which is
capable of explaining experimental observations as well as the
results of numerical calculations.
An experimental study on the lower alkanes and alkenes has shown
that the upper flammability limit (UFL) increases linearly with
temperature, except for mixtures lying inside the auto-ignition
range, the UFL of which increases more than linearly with
temperature. Moreover, it has been found that the UFL increases
with pressure, however, with a sharp decrease in slope at high
pressures, indicating the possible existence of a limit pressure
above which the UFL does not increase.
A new flammability criterion has been proposed to enable
distinction between local burning and flame propagation inside a
closed experimental set-up.
Different existing numerical methods have been evaluated. In the
absence of flame front instabilities, the application of a limiting
burning velocity has been found to predict the pressure dependence
of the UFL very well, while the application of a limiting flame
temperature generally has been found to slightly underestimate the
temperature dependence of the UFL.
- Auto-ignition limits
Many chemical processes use combustible gases and vapours at
elevated pressures and temperatures. In order to ensure the safe
and optimal operation of these processes, it is important to know
the lowest possible temperature at which spontaneous ignition of
these gases and vapours takes place. The auto-ignition temperatures
(AIT) found in literature usually are determined in small vessels
and at atmospheric pressure by applying standardised test methods
(e.g. EN 14522, IEC 60079-4, DIN 51794, ASTM 659-78 or BS 4056).
However, since the AIT is not constant but decreases with
increasing pressure and increasing volume, these AIT values are
often not directly applicable in industrial environments. The lack
of auto-ignition limit data at elevated pressures and the lack of
comprehensive auto-ignition models are the motivation for this
research.
- Past research: consequence modelling
Accurate prediction of the consequences of accidents requires
detailed models of a large number of physical phenomena, such as
fires, explosions, dispersion of gases, etc.
A theoretical and experimental study has been performed on the
phenomena occurring during pressure release of reservoirs filled
with liquefied gases, taking into account boiling heat transfer and
two-phase flow. This study has added new insight to the design of
safety valves.
The development of pressure waves (blast waves) during the
explosion of unconfined vapour clouds is not well understood. In
order to perform accurate calculation of their magnitude and
duration, suitable numerical techniques have been elaborated.
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The publication list can be expanded
by clicking on the "+".
- Journal papers
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Flammability limits
- Van den Schoor, F., Verplaetsen, F., Berghmans, J. (2008),
Calculation of the upper flammability limit of methane/hydrogen/air
mixtures at elevated pressures and temperatures, International
Journal of Hydrogen Energy 33, 1399-1406. (journal link)
- Van den Schoor, F., Verplaetsen, F., Berghmans, J. (2008),
Calculation of the upper flammability limit of methane/air mixtures
at elevated pressures and temperatures, Journal of Hazardous
Materials 153, 1301-1307. (journal link)
- Van den Schoor, F., Hermanns, T.T.E, van Oijen, J.A.,
Verplaetsen, F., de Goey, L.P.H. (2008), Comparison and evaluation
of methods for the determination of flammability limits, applied to
methane/hydrogen/air mixtures, Journal of Hazardous Materials 150,
573-581. (journal link)
- Van den Schoor, F., Verplaetsen, F. (2007), The upper
flammability limit of methane/hydrogen/air mixtures at elevated
pressures and temperatures, International Journal of Hydrogen
Energy 32, 2548-2552. (journal link)
- Van den Schoor, F., Norman, F., Tangen, L., Saeter, O.,
Verplaetsen, F. (2007), Explosion limits of mixtures relevant to
the production of 1,2-dichloroethane (ethylene dichloride), Journal
of Loss Prevention in the Process Industries 20, 281-285. (journal link)
- Norman, F., Van den Schoor, F., Verplaetsen, F. (2006),
Auto-ignition and upper explosion limit of rich propane-air
mixtures at elevated pressures, Journal of Hazardous Materials 137,
666-671. (journal link)
- Van den Schoor, F., Verplaetsen, F. (2006), The upper explosion
limit of lower alkanes and alkenes in air at elevated pressures and
temperatures, Journal of Hazardous Materials 128, 1-9. (journal link)
- Van den Schoor, F., Norman, F., Verplaetsen, F. (2006),
Influence of the ignition source location on the determination of
the explosion pressure at elevated initial pressures, Journal of
Loss Prevention in the Process Industries 19, 459-462. (journal link)
- Vandebroek, L., Van den Schoor, F., Verplaetsen, F., Berghmans,
J. Winter, H., van't Oost, E. (2005), Flammability limits and
explosion characteristics of toluene-nitrous oxide mixtures,
Journal of Hazardous Materials 120, 57-65. (journal link)
- Goethals, M., Vanderstraeten, B., Berghmans, J., De Smedt, G.,
Vliegen, S., van't Oost, E. (1999), Experimental study of the
flammability limits of toluene-air mixtures at elevated pressure
and temperature, Journal of Hazardous Materials 70, 93-104.
(journal link)
- De Smedt, G., de Corte, F., Notele, R., Berghmans, J. (1999),
Comparison of two standard test methods for determining explosion
limits of gases at atmospheric conditions, Journal of Hazardous
Materials 70, 105-113. (journal link)
- Vanderstraeten, B., Tuerlinckx, D., Berghmans, J., Vliegen, S.,
van't Oost, E., Smit, B. (1997), Experimental study of the pressure
and temperature dependence on the upper flammability limit of
methane/air mixtures, Journal of Hazardous Materials 56, 237-246.
(journal link)
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Auto-ignition limits
- Norman, F., Van den Schoor, F., Verplaetsen, F. (2006),
Auto-ignition and upper explosion limit of rich propane-air
mixtures at elevated pressures, Journal of Hazardous Materials 137,
666-671. (journal link)
- Vandebroek, L., Verplaetsen, F., Berghmans, J., van den
Aarssen, A., Winter, H., Vliegen, G., van't Oost, E. (2002),
Auto-ignition hazard of mixtures of ammonia, hydrogen, methane and
air in a urea plant, Journal of Hazardous Materials 93, 123-136.
(journal link)
- Caron, M., Goethals, M., De Smedt, G., Berghmans, J. Vliegen,
S., van't Oost, E., van den Aarssen, A. (1999), Pressure dependence
of the auto-ignition temperature of methane/air mixtures, Journal
of Hazardous Materials 65, 233-244. (journal link)
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Past research: consequence modelling
- Boesmans, B., Berghmans, J. (1996), Modelling boiling delay and
transient level swell during emergency pressure relief of liquefied
gases, Journal of Hazardous Materials 46, 93-104. (journal link)
- Vanderstraeten, B., Lefebvre, M., Berghmans, J. (1996), A
simple blast wave model for bursting spheres based on numerical
simulation, Journal of Hazardous Materials 46, 145-157. (journal link)
- Boesmans, B., Berghmans, J (1995), Level swell in pool boiling
with liquid circulation, International Journal of Heat and Mass
Transfer 38, 989-998. (journal link)
- Boesmans, B., Berghmans, J. (1995), Axial void fraction
distribution effects on level swell during emergency pressure
relief, Journal of Loss Prevention in the Process Industries 8,
3-10. (journal link)
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- Conference papers
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Flammability limits
- Van den Schoor, F., Verplaetsen, F., Berghmans, J. (2007),
Calculation of the upper explosion limit of methane-air mixtures at
elevated pressures and temperatures, Proc. 12th Int. Symp. on Loss
Prevention and Safety Promotion in the Process Industries,
Edinburgh, United Kingdom.
- Van den Schoor, F., Verplaetsen, F., Berghmans, J. (2007),
Calculation of the upper explosion limit of methane-air and
propane-air mixtures at elevated pressures and temperatures, Proc.
5th Int. Seminar on Fire and Explosion Hazards, Edinburgh, United
Kingdom.
- Van den Schoor, F., Verplaetsen, F., Berghmans, J. (2007),
Experimental and numerical study of the influence of pressure and
temperature on the flammability limits of combustible gases in air,
Proc. 3rd European Combustion Meeting, Chania, Crete, Greece.
- Vandebroek, L., Van den Schoor, F., Verplaetsen, F., Berghmans,
J., Winter, H., van't Oost, E. (2004), Flammability limits of
CH4-H2-N2O-mixtures at elevated pressures, Proc. 11th Int. Symp. on
Loss Prevention and Safety Promotion in the Process Industries,
Praha, Czechia.
- Van den Schoor, F., Verplaetsen, F., Berghmans, J. (2004), The
upper flammability limit of ethane, propane and n-butane in air at
elevated pressures and temperatures, Proc. 11th Int. Symp. on Loss
Prevention and Safety Promotion in the Process Industries, Praha,
Czechia.
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Auto-ignition limits
- Norman, F., Verplaetsen, F., Berghmans, J. (2007), Experimental
validation of auto-ignition models for methane-air mixtures at
elevated pressures, Proc. 5th Int. Seminar on Fire and Explosion
Hazards, Edinburgh, United Kingdom.
- Norman, F., Vandebroek, L., Verplaetsen, F., Berghmans, J.
(2007), Influence of ammonia on the auto-ignition limits of
methane/air mixtures, Proc. 3rd European Combustion Meeting,
Chania, Crete, Greece.
- Norman, F., Vandebroek, L., Berghmans, J., Verplaetsen, F.
(2006), Numerical study of the auto-ignition process in methane-air
mixtures at elevated pressures, Proc. 13th Int. Heat Transfer
Conference, Sydney, Australia.
- Vandebroek, L., Verplaetsen, F., Berghmans, J., van den
Aarssen, A., Winter, H., Vliegen, G., van't Oost, E. (2001),
Auto-ignition hazard of ammonia, hydrogen, methane and air in a
urea plant, Proc. 10th Int. Symp. on Loss Prevention and Safety
Promotion in the Process Industries, Stockholm.
- Winter, H., van den Aarssen, A., Vliegen, G., van't Oost, E.,
Meessen, J., Gotte, F., Vandebroek, L., Berghmans, J. (2001),
Detonation hazards of mixtures of ammonia, hydrogen, methane and
air in process piping at 150 bara, Proc. 10th Int. Symp. on Loss
Prevention and Safety Promotion in the Process Industries,
Stockholm.
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- Dissertations
- Norman, F., (2008), Influence of Process Conditions on the
Auto-ignition Temperature of Gas Mixtures, PhD thesis, Katholieke
Universiteit Leuven
- Van den Schoor, F., (2007), Influence of Pressure and
Temperature on Flammability Limits of Combustible Gases in Air, PhD
thesis, Katholieke Universiteit Leuven
- Vanderstraeten, B. (1998), Numerical Simulation of Gas Cloud
Blast Waves, PhD thesis, Katholieke Universiteit Leuven
- Boesmans, B. (1994), Transient Level Swell During Emergency
Pressure Relief of Liquefied Gases, PhD thesis, Katholieke
Universiteit Leuven
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- Laboratory for Industrial Safety
The Laboratory for Industrial Safety is an
initiative of the Division of Applied Mechanics and Energy
Conversion of the Mechanical Engineering Department. It is the
result of research of many years' standing in the field of
industrial safety under the supervision of Em. prof. Jan
Berghmans.
The laboratory is equipped with experimental set-ups to determine a
number of gas explosion characteristics as
a service to industry.
- Spin-offs
The research on industrial safety under the supervision of Em.
prof. Jan Berghmans has led to the formation of two spin-off
companies: Protec Engineering (which is now a division of M-tech) and Adinex.
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Vacant PhD positions are listed on the website of the Arenberg
Doctoral School. |
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Dr.ir. Filip Van den
Schoor
Katholieke Universiteit Leuven
Department of Mechanical Engineering, Division TME
Celestijnenlaan 300A, B-3001 Leuven, Belgium
Tel: +32 16 322549
Fax: +32 16 322985
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