Neqsim Gas Scrubber Sizing Screening

Gas Scrubber Sizing Screening

Use this skill for public, educational gas-scrubber (vertical separator) sizing screening. It estimates the Souders-Brown maximum gas velocity, the required vessel diameter, the velocity utilisation against an existing diameter, and a mist-eliminator gas-load check so an agent can scope a separator-sizing study before detailed design.

When to Use

• When a user asks what diameter a vertical gas scrubber needs or whether an existing vessel is large enough.
• When an agent needs a quick Souders-Brown velocity and mist-eliminator load estimate.
• When examples must run without confidential vessel data, vendor internals data, or company specs.

Inputs

• gas_mass_flow_kg_s: gas mass flow in kg/s.
• gas_density_kg_m3: gas density in kg/m3.
• liquid_density_kg_m3: liquid density in kg/m3.
• k_factor_m_s: Souders-Brown K-factor in m/s, default 0.107.
• vessel_inside_diameter_m: optional existing vessel inside diameter; if given it is checked, otherwise the required diameter is sized.
• mist_eliminator_k_factor: mist-eliminator K-factor in m/s, default 0.12.
• demister_present: whether a mist eliminator is installed, default True.

Outputs

• souders_brown_velocity_m_s: maximum gas velocity v_max.
• gas_volumetric_flow_m3_s: actual gas volumetric flow Q.
• required_area_m2: required cross-sectional area Q / v_max.
• required_diameter_m: required vessel inside diameter.
• actual_velocity_m_s: actual gas velocity at the given diameter, or null.
• velocity_utilisation: actual velocity divided by v_max, or null.
• gas_load_factor: effective K-factor from the actual velocity, or null.
• demister_velocity_limit_m_s: mist-eliminator Souders-Brown limit.
• demister_utilisation: gas velocity divided by the demister limit, or null.
• sizing_warning: ok, watch, undersized, or oversized.
• demister_warning: ok, watch, mist-eliminator-overloaded, or no-demister.
• assumptions: public assumptions used by the placeholder model.

Engineering Method

The Python class GasScrubberSizingModel uses open separator-sizing relations only:

• Souders-Brown velocity uses v_max = K sqrt((rho_l - rho_g) / rho_g).
• gas volumetric flow uses Q = mdot / rho_g.
• required area uses A = Q / v_max and required diameter uses D = sqrt(4 A / pi).
• when a diameter is given, actual velocity uses v = Q / (pi/4 * D^2), velocity utilisation uses v / v_max, and the effective K-factor uses v / sqrt((rho_l - rho_g) / rho_g).
• the demister limit uses v_demister = K_mist sqrt((rho_l - rho_g) / rho_g), and demister utilisation uses v / v_demister.

This is educational and screening-only logic. It assumes a vertical vessel with uniform gas velocity, ignores inlet-device performance, liquid handling, and settling-section detail, and is not a replacement for validated separator sizing or qualified review.

Python Usage Pattern

from gas_scrubber_sizing_screening import GasScrubberSizingModel

model = GasScrubberSizingModel()
result = model.evaluate(
    gas_mass_flow_kg_s=8.0,
    gas_density_kg_m3=45.0,
    liquid_density_kg_m3=700.0,
    vessel_inside_diameter_m=1.2,
)

print(result.souders_brown_velocity_m_s)
print(result.velocity_utilisation)
print(result.sizing_warning)
print(result.demister_warning)

Related NeqSim Functionality

For validated separator sizing, redirect to NeqSim classes:

• neqsim.process.equipment.separator.Separator — process separator with gas/liquid split and performance.
• neqsim.process.mechanicaldesign.separator.SeparatorMechanicalDesign — separator mechanical design, gas-load factor, and retention time.
• neqsim.process.mechanicaldesign.separator.internals.DemistingInternal — mist-eliminator Souders-Brown limit and carry-over model.
• neqsim.process.equipment.separator.GasScrubberDesign — proposed dedicated gas-scrubber sizing model; candidate NeqSim gap.

This skill is a public triage layer that decides when to invoke a validated separator-sizing model.

Validation Checklist

• Gas and liquid densities are positive and rho_l > rho_g.
• K-factors and mass flow are positive.
• Tests cover sizing without a diameter, an undersized vessel, a demister-overload case, and invalid input.
• Results are described as educational screening indicators.
• Real sizing is redirected to validated NeqSim separator classes and qualified review.

Common Mistakes

Limitations

• No proprietary vessel data, vendor internals data, or company specs are included.
• Inlet-device performance, liquid handling, and settling-section detail are not modelled.
• A single Souders-Brown K-factor is used for the gas-capacity check.

References

• GPSA Engineering Data Book, Section 7, Separators and Filters.
• API Recommended Practice 12J, Specification for Oil and Gas Separators.
• NeqSim repository: https://github.com/equinor/neqsim