Dynamic flare system analysis

Best practice engineering

As operating companies look to maximize the value from their existing infrastructure, particularly in brownfield development projects, there is an increasing requirement to accurately assess the suitability of a facility’s flare system.

Furthermore, tightening industry guidelines, such as the requirement to ensure that suitable materials of construction are applied, means that accurate dynamic flare system analysis is increasingly at the heart of design and asset integrity decisions.

In particular, dynamics provide much higher-accuracy information for low-temperature and capacity analysis. This means that it is possible to minimise CAPEX decisions while remaining within safe operating limits.

Key advantages of dynamic flare system analysis

Dynamic analysis using PSE’s gFLARE technology brings a number of key advantages, as can be seen in the diagram below:

gFLARE® enhances the accuracy of capacity analysis by taking into account:

  1. Line packing, to account for the time taken to pressurise the flare system. [including packing into inactive parts of the flare system]
  2. Coupled process and flare system, to reflect the fact that the transient behaviour of the flare system is largely determined by the process dynamics during the emergency scenario that is being analysed
  3. Reverse flow into the process and inactive (non-flowing) tailpipes and headers. Flow can go in any direction in what is effectively a large open system with flow into inactive (non-flowing) tailpipes, headers and back into low pressure sources.
  4. Potential for staggered blowdown. Many plant blowdown strategies already rely on the transient nature of system depressurization (i.e. peak flows are momentary).
  5. The actual peak flow at the flare tip – which because of packing and other effects is much lower than the sum of instantaneous peak flows – can be accurately assessed, to allow meaningful design decisions.
  6. Cold and hot front penetration into the flare system. Without dynamic analysis it is impossible to determine how much of a flare system is cooled during a depressuring event.

Apply high-fidelity dynamic modelling to your flare system analysis

The use of a rigorous model-based safety approach based on our gFLARE technology and coupled process and flare network models can result not only in improved process safety but also an improvement in operations and a considerable reduction in CAPEX. Read our case studies to find out how Oil & Gas companies are saving billions.

More Information
The designer should determine the range of temperatures and pressures of the fluids entering the flare header for each mode of operation.

A heat transfer analysis may also be performed that considers the amount of material released and the duration of those events which can cause the header to reach high and low temperature extremes.
API 521 6ED

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