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fluidyn
Assess-Risk
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A Software for Risk and Consequences Analysis for Chemical & Petrochemical sites
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fluidyn
ASSESS RISK is a Fluid Dynamics Software Package designed for Risk Analysis and Planning of Petrochemical Refineries and Bulk storage Installations.
fluidyn ASSESS-RISK is based on
UFTP (Union Francaise d'Industrie Petroliere) methodology and is a result of participant's exercises. The Techniques imposed for Risk Assessment
are based on qualitative methods, semi-quantitative criteria or quantitative methods and validated by
INERIS.
The objective is to identify the critical systems to avoid major-accident hazards and to limit their consequences to environment and Productivity of the Plants. They are:
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Identification of the safety relevant sections of the
establishment
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Identification of critical systems at the origin of potential major accidents.
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Determining the magnitude of potential major accidents.
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Assignment and assessment of the prevention, control and mitigation measures.
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The definitions of the emergency plan distances. (Evacuation of the population)
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Increasing the units’ operation reliability.
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Natural
Gas Explosion
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PHYSICAL MODEL
NUMERICAL FEATURES
USER INTERFACE
IO PARAMETER
APPLICATIONS
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PHYSICAL
MODELS
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Simulation of Scenarios and Sub-Scenarios will be based on the appropriate conditions. Forty- five probable Scenarios and Sub-Scenarios are possible, such as
- BLEVE (Boiling Liquid expanding Vapor Explosion)
- UVCE (Unconfined Vapor Cloud Explosion)
- Boilover Fireball
- Missile effects
- Ballist
- Jet Fire
- Flash Fire
- Pool Fire
- Shock Wave
- Domino effect, etc.,
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The basic approach is the evaluation of both the level of consequence and the associated level of probability. Here the consequences and the probabilities are divided into six
categories. Different Regulations consider the three levels of Risk as Lethal,
Destruction and Irreversible. Risks are classified into four types, they are:
Risk due to Toxic Dispersion:
The critical toxic limits selected are IDLH, LC1%, LC50%, LC99% or ERPG-3.
Risk due to Over Pressure:
Rupture of Pressure Vessels and Pressure Capacities Rupturing could result in Thermal Explosion, Confined Explosion, Physical Explosion and Pneumatic Explosion. The positive peak over pressures lead to Direct blast lethality, Indirect blast lethality, Damages to equipment and third party properties and Seismic effects.
Risk due to Thermal Radiation:
All models of heat transfer are involved to some degree, but the most important is the open plant Radiation.
Here we make use of the radiation intensity limits described by TOTAL and
SINCOR as consequence criteria to calculate the lethality, first degree burns and second degree burns.
Risk due to Missile Effects:
The energy absorbed during the destruction of the shell of the involved capacity, represents a very small proportion of an internal initial energy. Once the shall is destroyed, the fragments are ejected in to the environment absorbing
bulk of residual energy due to over pressure. This model has been jointly developed by
TNO, CREMER & WERNER and TOTAL. In addition,
it has been validated by
INERIS.
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NUMERICAL
FEATURES
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Exact simulation of flow in the refinery is simulated with the 3D finite
volume approach. Automatic mesh generator is used to generate the mesh over
the refinery area. The equations are discretised both in three
dimensional space and time. The spatial discretization is done over a three
dimensional mesh made up of arbitrary hexahedrons. Control-volume or
integral-balance approach is used to construct the finite difference
approximations for each of these control volumes to preserve local
conservation of differenced quantities.
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USER INTERFACE
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The
graphical user interface is menu driven, user-friendly and easy to use.
Online context help is available for quick help. User can see all the views
in 2D or 3D format.
The
pre-processor consists of the following modules:
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Manual creation of computational domain, Refinery (Site, Unit & Section), Equipments, Fluid database,
Confidential fluid mixtures, Threshold database and Meteorological stations.
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Save terrain, meteorological, equipments and result files in ASCII format.
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Save simulation options.
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Update the Fluid database through menu.
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Load meshes in different formats.
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Load simulation options.
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Load terrain, meteorological and case definition in ASCII format.
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Interactive specification of boundary conditions.
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Manual control over simulation options.
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Damage circles can be drawn for different risk criteria.
The
post-processor has multiple view port capability. Each view port can have
many plots.
The following plots can be drawn:
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Terrain view with object masking facility.
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Grid plots.
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Vector plot.
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Contour plot: line, filled and paint.
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Surface plot: line, filled and paint.
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X Y graphs of residual history.
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Trace plots of any variable at monitor points.
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Examine to see the values at any grid points and distance between any two points.
Zoom-in
and Zoom-out facility is available in both pre and post processors.
Animation facilities with text / graphical annotation are available for
playback. Hardcopy plots on HPGL and PostScript plotters are possible.
Pictures can be stored as Bitmap files (*.bmp).
The
Post-Processor can dynamically display the results (in the form of selected
plots) while the solver is running. Thus, the results obtained can be
monitored, input parameters changed, and the solver re-run all without
leaving the software environment. The dynamic post-processor further allows
the user to monitor the progress of solution in case of complex problems
thereby reducing total solution time.
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INPUT
& OUT PARAMETERS
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INPUT PARAMETERS
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OUTPUT PARAMETERS
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- Geometry of the domain
- Terrain data
- Meteorological data
- Fluid properties
- Equipment data
- Threshold Data
- Target Data
- Boundary conditions
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- Pressure and Total Head at Various locations.
- Velocity components U, V, W at various locations.
- Pollutant quantity or concentration level at various locations
- Density and viscosity variations (due to pollutants) at various locations.
- Temperature gradients at different locations.
- Time averaged concentration of pollutants.
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APPLICTAIONS
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Ii
is specially designed to simulate fire accidents
occurring in Petroleum Refineries.
- UFIP methodology evaluated by
INERIS
- Analysis of accidental events on petrochemical sites by deterministic and probabilistic methods
- 13 equipments considered (most often used by industries)
- 45 possible scenarios : tank fire, explosion with blast and fire ball effect, BLEVE, UVCE, boil-over, pool
fire…
- Parameters considered : statutory thresholds, probability parameters, operational & meteorological data,
site, fluid & equipment characteristics
- Results presented as damage contours in graphics and tabular forms
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