neqsim-co2-emissions-screening

name	neqsim-co2-emissions-screening
calculation_basis	screening
version	0.1.0
description	Educational combustion-CO2 emission screening that estimates the CO2 mass rate from a fuel-gas flow and composition using public per-component carbon-count stoichiometry and the IPCC basis. USE WHEN: a task needs a public, screening-level CO2 emission rate (kg/s or tonnes/day) from burning a fuel-gas stream before detailed combustion or emission-factor reporting.
last_verified	2026-06-18
requires	{"python_packages":[],"java_packages":[],"env":[],"network":[]}

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

Symptom	Cause	Fix
Emission too low	Feed CO2 ignored	The model carries feed CO2 through
Component rejected	Heavy or uncommon species	Limit to the supported fuel-gas list
Wrong basis	Both flows passed	Provide exactly one flow basis

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