ASPEN FLARE SYSTEM ANALYZER/

FLARENETBy

GAUTHAM SProcess Engineer

SimulationIt 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 AVAILABLEAspen Hysys, Aspen Plus, Unisim, Pro II, Flarenet, Pipesim, Pipenet, etc

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.

Flare Scheme Simulation• Aspen Flare System Analyzer is a software to simulate the

flare system network. • It was previously called Flarenet.

Basis of Simulating a Flare Network Scheme

• Define the Composition• Define the Flare Network• Define the Sources• Define the Scenarios

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

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

Example of a Flare Network

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.,

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.

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

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

THANK YOU