All-inclusive relief system analysis with integrated PSV, network header and stack design 

The Flare workspace in the Symmetry platform offers a complete set of flare & relief system design tools that empowers users to verify the performance of their entire safety system with steady-state or dynamics.

The unique scope of modeling tools advances both the value and efficiency of safety simulation. 

The fully-integrated Flare workspace allows models to suit any application. Users are empowered to analyze standalone components or complete systems, with various levels of detail, in steady-state or dynamics.

Process and Flare Models

An existing process model can define conditions for a relief valve sizing and installation model, which may evolve into a header rating model with constraint evaluation across global scenarios. These flare models are easily updated when there are changes in the process.

Relief Valve and Network Models

A scenario-driven model of the header system can report an increase in backpressure on a relief valve, automatically trigger an update to valve rating calculations, and verify inlet losses at the new rated flow. Likewise, a change in relief valve size or type is automatically taken into account in header constraint evaluation. 

Steady-State and Dynamics

The unique level of integration between steady-state and dynamics solvers in the Symmetry platform allows users to analyze the bulk of scenarios in steady-state and invest in dynamics analysis where it matters.

Critical scenarios can be solved in dynamics, starting from the steady-state model and adding details and scheduled events for rigorous time-based analysis. Dynamics gives insight into the severity of constraint violations, including the duration of a violation and the real impact on equipment behavior. Taking into account system volumes and staggered relief times makes for a more realistic analysis, and in many cases will result in conditions being farther from constraint violation or requiring less drastic (and expensive) upgrades to meet safety criteria.

Using the right tool for an application is seamless in the Flare workspace, without transfer of data across applications or a spread of models across separate environments, so users can reap the benefits with less effort.

Scenario management in a flowsheet environment offers comprehensive identification of specific safety concerns and the capacity for detailed analysis.

Define relief scenarios for standalone sources and/or full header networks to verify that the model meets safety constraints for every potential event. Constraint limits for relief valves and the header network are monitored, and key results are shown per scenario, color-coded and sorted for efficient identification of bottlenecks.

Active scenario selection provides users access to any variable calculated in a scenario, including all the hundreds of property profiles and variables available in unit operation forms, as well as built-in access to multiple post-analysis tools that allow for deeper analysis and system understanding.

The Symmetry platform advantage means rigorous thermodynamics, mature engines, and an enhanced user experience.

The Flare workspace builds upon the legacy of VMGSim technology and helps users get the most out of their flare models with the Symmetry platform. Industry-proven thermodynamics from VMGThermo enable accurate prediction of properties, consistent characterization across models, and detection of vulnerabilities like hydrate and solid formation. The steady-state, dynamics, and network solver engines bring decades of experience solving related systems in industry, with the steady-state network solver now adding kinetic energy tracking for flare applications. The Symmetry platform has a variety of tools including case studies, emission monitoring, and a new equipment database that enable deeper, asset-wide insight.  

Scenario Management

Define relief scenarios for standalone sources and/or full header networks to verify that the model meets safety constraints for every potential event. Constraint limits for relief valves and the header network are monitored, with inlet and tailpipe constraints optionally evaluated at the required or rated flow.

Valid sources are automatically detected from Flare flowsheets and assigned relief conditions as specified in the running scenario. Key results are shown per scenario in the Flare Scenario Manager, color-coded and sorted by their approach to constraint violation for efficient identification of bottlenecks.

Active scenario selection defines the specifications and results shown on the flowsheet. Switching to a previously-run scenario restores its network solution with all calculated values. Users have access to any calculated property in a scenario by opening unit operation forms and delving into the hundreds of property profiles and variables available, as well as having access to multiple post-analysis tools like case studies, the line list, and a flow path viewer.

Key Features:
  • Create, add, clone scenarios 
  • Auto-detection of valid sources from control valves, blowdown valves, and relief valves
  • Select, change, or remove an active source
  • Support Relieving T or Vapor Fraction, P, Composition and Flow for each source per scenario
  • Inactive sources are automatically specified
  • View active scenario on the PFD, with the ability to both specify the scenario from the flowsheet and inspect all calculated values (including access to apply any tool like the flow path viewer or case studies)
  • Restore full network results when switching to an active scenario that was previously calculated
  • Specification and evaluation of relief valve constraints (MABP, Inlet losses)
  • Specification and evaluation of network constraints (Mach, RhoV2) for headers and tailpipes including specification of a tolerance for the given limit
  • Inlet and tailpipe constraints evaluated at required or rated flow  
  • Visualization of scenario status and specific points of constraint violation with stored results
  • Multiple stand-alone relief devices and networks can be specified within the same scenario, even in separate flowsheets
  • Reference flowsheet selection relevant for multi-flowsheet cases
Relief Valves
  • Relief limit calculations for:
    • Allowable accumulation, overpressure based on fire case / not and installation type
    • Relieving pressure based on MAWP/Set Pressure
    • Maximum Allowed Backpressure (MABP) from valve type and Set Pressure
  • Sizing & rating side-by-side with capacity check
    • Sizing using Homogeneous Equilibrium Method, based on the Homogeneous Equilibrium Flow Model (HEM) valid for any fluid phase
    • Variety of options for two-phase relief discharge coefficient
    • Display of results across all scenarios
    • Determination of governing scenario and ability to select minimum required API size
    • API and ASME (Vendor) sizes supported to be used with matching discharge coefficients
    • Solve at MABP or network backpressure (assumed or connected live to header network)
  • Inlet loss calculations at required or rated flow
  • Noise prediction
  • Warnings if maximum allowable set pressure or backpressure are exceeded
Convergent, Divergent, Looped Networks
  • Steady-state and dynamics solvers
    • Multiphase support
    • Kinetic energy tracking
    • Multiple flare stack support
    • Relief valve, blowdown valve (orifice) and control valve sources
    • Nested flowsheets for multi-flowsheet networks
    • Support organizing the network across multiple nested flowsheets
    • T-Junction friction losses (Miller method)
    • Critical flow (choke) prediction
    • Losses due to pipe diameter changes
    • Implicit enlargers & reducers added for diameter changes between pipes or at connection with junctions
    • Junction diameter specification
    • Frictional losses at separator entrance and exit
    • Flare tip curve support
  • Detailed Heat Loss
    • Wall material & insulation layers
    • Ambient conditions
    • Axial heat transfer (dynamics)
Tailored User Interface
  • Custom PFD palette focused on relevant unit operations for relief devices, header network, and utility unit operations
  • Flare ribbon with access to active scenario selection, status, and other relevant tools like the Scenario Manager, Flow Path Viewer and Model Audit
  • Model Audit tool to monitor steady-state network specifications and provide warnings and insight about the model in both steady-state and dynamics
  • Line list with summary of data for all pipes and functionality that includes bulk editing, filtering, and sorting
Symmetry Platform Assets
  • VMGThermo
    • Proven rigorous thermodynamic engine
    • Hydrates and solid formation prediction
    • Consistent fluid characterization
  • Productivity tools
  • Case studies, optimizer, regression
  • Equipment database
  • Interaction with Process or Pipe model
    • Model any facility or pipe network
    • Model scenarios
    • Specify scenario conditions from process or scenario model
  • Reporting tools
    • Case report
    • Data sheets
    • Line list
    • Flow path viewer

Contact Us

To find out how VMG can help you solve your process challenges, email or call in the U.S. and Canada at (403) 457-4595. For all other inquiries, please fill out the form below.

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