(49b) Design Considerations for Pressurized Flare and Vent Systems for Efficient CO2 Management

We explore the concept of segregating high CO2 systems into a pressurized flare header. This innovative approach mitigates the risk of low temperatures and dry ice formation, reducing the likelihood of blockages. This is demonstrated through typical design options for Floating Production Storage Offloading facilities and CCS applications.

Design calculations show that maintaining pressure between 16barg and 7barg is crucial. This limit is governed by the accurate prediction of the process side fluid temperature, which requires an accurate representation of the thermodynamic and process system behavior. The subsequent Joule Thompson effect from the worst-case composition can be captured and used to calculate the tailpipe and header fluid and metal temperatures. Design constraints such as flare capacity and API 15 min depressurization time may require staggering systems and procedural decreases in pressurized flare pressure.

This work presents a comprehensive discussion of the design challenges encountered in CCS and high CO2 gas field development projects. It introduces an innovative concept of flare segregation, which is not common in the petroleum industry but is expected to gain prevalence in the coming years with the expansion of CCS projects. Most commercial process simulators face challenges when it comes to handling high CO2 content and high-pressure conditions, such as those found with dense phase. The need for advanced Equation of State (EoS) models like GERG and SAFT-γ Mie, specifically designed for CO2-rich systems with impurities (H2, Ar, N2), and the implementation in a commercial process simulation package is demonstrated.