CO2 Emissions Screening

Use this skill for public, educational combustion-CO2 emission screening. It estimates the CO2 mass rate from full combustion of a fuel-gas stream using public per-component carbon counts, so an agent can scope an emission rate before detailed combustion modelling or certified emission-factor reporting.

When to Use

• When a user asks roughly how much CO2 a fuel-gas stream produces when burned.
• When an agent needs a quick emission rate for turbine, heater, or flare fuel.
• When examples must run without confidential metering or certified emission factors.

Inputs

• composition: dict of component name to mole fraction (normalized internally).
• molar_flow: fuel-gas molar flow in mol/s (provide this or mass_flow).
• mass_flow: fuel-gas mass flow in kg/s (provide this or molar_flow).
• co2_limit_t_per_day: optional CO2 limit in tonnes/day for the flag.

Supported components: methane, ethane, propane, n/i-butane, n/i-pentane, hexane, CO2, CO, nitrogen, hydrogen, water, oxygen, H2S, helium.

Outputs

• mixture_molecular_weight_g_mol: composition-weighted molecular weight.
• carbon_per_mole_fuel: carbon atoms per mole of fuel mixture.
• co2_mass_rate_kg_s: CO2 mass rate.
• co2_mass_rate_t_per_day: CO2 rate in tonnes/day.
• specific_co2_kg_per_kg_fuel: CO2 mass per unit fuel mass.
• emission_warning: ok, over-limit, or no-limit.
• assumptions: public assumptions used by the placeholder model.

Engineering Method

The Python class CombustionCO2Model uses public combustion stoichiometry:

• the carbon per mole of fuel uses C = sum(y_i * carbon_number_i).
• the CO2 mass rate uses m_CO2 = n_fuel * C * M_CO2 with M_CO2 = 44.01 g/mol.
• complete combustion is assumed, so every fuel carbon atom becomes one CO2; feed CO2 is carried through and counted.
• mass-flow input is converted to molar flow with the composition-weighted molecular weight.

This is educational and screening-only logic. It assumes complete combustion with no combustion efficiency, unburned-carbon slip, flaring loss, or capture credit. It is not a replacement for validated combustion modelling, ISO 6976 calculations, certified emission factors, and qualified reporting.

Python Usage Pattern

from co2_emissions_screening import CombustionCO2Model

model = CombustionCO2Model()
result = model.evaluate(
    composition={"methane": 0.9, "ethane": 0.07, "co2": 0.03},
    mass_flow=2.0,
    co2_limit_t_per_day=400.0,
)

print(result.co2_mass_rate_t_per_day)
print(result.specific_co2_kg_per_kg_fuel)
print(result.emission_warning)

Related NeqSim Functionality

For validated combustion and gas-quality behaviour, redirect to existing NeqSim classes:

• neqsim.standards.gasquality.Standard_ISO6976 — calorific value, density, and Wobbe index per ISO 6976.
• neqsim.process.equipment.reactor.GibbsReactor — equilibrium combustion product modelling.
• neqsim.process.equipment.powergeneration.GasTurbine — fuel-gas consumption and turbine duty.

This skill is a public emission-rate triage layer that decides when to invoke those validated combustion and gas-quality classes.

Validation Checklist

• Composition fractions are non-negative and sum to a positive value.
• Exactly one of molar_flow or mass_flow is supplied.
• All components are in the supported list.
• Tests cover methane stoichiometry, mass-flow basis, inerts/CO2, limit flag, and invalid input.
• Real emission accounting is redirected to validated NeqSim tools and qualified review.

Common Mistakes

Limitations

• Complete combustion only; no efficiency, slip, or capture.
• Limited fuel-gas component set; no heavy hydrocarbons or oxygenates.
• Not a certified greenhouse-gas inventory method.

References

• NeqSim repository: https://github.com/equinor/neqsim
• NeqSim Skills Guide: https://github.com/equinor/neqsim/blob/master/docs/integration/skills_guide.md