This document discusses simulation of an aspen flare system using Aspen Flare System Analyzer software. It describes defining the composition, flare network scheme, sources such as control valves and pressure safety valves, and scenarios to simulate, such as all relief devices activating. The outcomes of the simulation can be used to design and verify the flare header size and other parameters meet API standards. The simulation aims to size the flare system and verify its performance under different operating conditions.

1. ASPEN FLARE SYSTEM
ANALYZER/ FLARENET
By
GAUTHAM S
Process Engineer

2. Simulation
It is the process of examination of a problem not by subjecting a direct
experimentation but by a software capable of producing the results under
certain caveats.
SOFTWARES AVAILABLE
Aspen Hysys, Aspen Plus, Unisim, Pro II, Flarenet, Pipesim, Pipenet, etc

3. Selection of Simulator
• The different simulator available are Aspen HYSYS, Aspen Plus, Unisim, PRO II,
etc.,
• VB, the liquid molar volume at the boiling point TB, for Water is wrong in the
Aspen Plus databank PURE10. In PURE10, the value of VB in CC/MOL is
1401.38; however, the value should be 18.5064 CC/MOL. This property VB used in
some transport properties, viscosity, diffusion coefficient like Wilke Chang model. It
will not effect liquid density calculations
• The knowledge of limitations of different simulators is necessary to choose the
effective simulator.

4. Flare Scheme Simulation
• Aspen Flare System Analyzer is a software to simulate the flare system
network.
• It was previously called Flarenet.

5. Basis of Simulating a Flare Network
Scheme
• Define the Composition
• Define the Flare Network
• Define the Sources
• Define the Scenarios

6. Define the Flare Network
• It involves the routing of the flare network.
• The header, pipes, vessel and associated fittings involved will be taken into
account. It is incomplete without the addition of the sources

7. Define the Sources
• The various sources are
 Control Valves
 Pressure Safety Valves
 Blow down Valves with Restriction Orifice
• To define the sources, we need the following
 PSV SIZING DATA
 Process Simulation (HYSYS File)
 Depressuring Calculation

8. Example of a Flare Network

9. Define the Scenarios
• The one default scenario is when all relief devices go mayhem
• The others can be Blocked Discharge, Power failure, Control Valve failure
Emergency Blowdown etc.,

10. Outcome of Flare Scheme Simulation
• The pipes such as flare header size can be designed and verified as per API
recommended practice.
• Calculations involving MACH No / Velocity /Pressure drop /Noise limit
can also be designed and verified as per API Standards.

11. Flare Simulation Development
Methodology
• Flare composition and Molecular Weight
• Inlet pressure and temperature at Control Valves
• PSV governing cases and their respective orifice size
• Dimensions of pipes, vessels and associated fittings involved
• Client specification on Flare system
• Flare Network Scheme

12. Flare Simulation Report
• Introduction
- Background & Objectives
• Basis of Simulation Study
- Scope of the study
- Reference documents
- Test run review for different
Scenarios
• Results of the simulation study
- Quality of test run
simulations
- Alternative Sizing or Rating
results
- Robustness of the design
- Conclusion

13. THANK
YOU