NeqSim Documentation

NeqSim (Non-Equilibrium Simulator) is a comprehensive Java library for thermodynamic, physical property, and process simulation developed by Equinor.

🚀 Get Started ⭐ Star on GitHub 📖 Reference Manual

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Quick Navigation

📚 Core Documentation

• Getting Started
  Installation and first steps
• Modules Overview
  Architecture and package structure
• Reference Manual
  Complete API documentation

🔬 Thermodynamics

• Thermo Package
  Equations of state, mixing rules, fluids
• Thermodynamic Operations
  Flash calculations, phase envelopes
• Physical Properties
  Viscosity, conductivity, diffusivity

🏭 Process Simulation

• Process Equipment
  Separators, compressors, heat exchangers
• Fluid Mechanics
  Pipeline flow, pressure drop
• Safety Systems
  Relief valves, flare systems

📊 Applications

• PVT Simulation
  Reservoir fluid characterization
• Black Oil Models
  Simplified correlations
• Field Development
  Integrated workflows

⚠️ Risk & Reliability

• Risk Simulation
  Equipment failure, Monte Carlo analysis
• SIS/SIF Integration
  IEC 61508/61511, LOPA, SIL verification
• Bow-Tie Analysis
  Barrier analysis, threat visualization

🎯 Optimization & Cost

• Production Optimization
  Throughput, multi-objective, Pareto
• Cost Estimation
  CAPEX, OPEX, financial metrics
• External Optimizers
  Python/SciPy integration

🌱 Emissions & Sustainability

• Emissions Hub
  Landing page for all emission documentation
• Offshore Reporting Guide
  Regulatory framework, methods, validation
• Emissions Tutorial
  CO₂, methane, nmVOC from produced water

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⚡ Quick Start Example

import neqsim.thermo.system.SystemSrkEos;
import neqsim.thermodynamicoperations.ThermodynamicOperations;

// Create a natural gas fluid
SystemInterface gas = new SystemSrkEos(298.15, 50.0);
gas.addComponent("methane", 0.90);
gas.addComponent("ethane", 0.05);
gas.addComponent("propane", 0.03);
gas.addComponent("CO2", 0.02);
gas.setMixingRule("classic");

// Perform flash calculation
ThermodynamicOperations ops = new ThermodynamicOperations(gas);
ops.TPflash();

// Get properties
System.out.println("Density: " + gas.getDensity("kg/m3") + " kg/m³");
System.out.println("Compressibility: " + gas.getZ());

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📖 Documentation Sections

Section	Description
🧪 Thermodynamics	Equations of state, phase behavior, component properties
⚙️ Process Simulation	Unit operations, process systems, controllers
🔄 Dynamic Simulation	Transient simulation, time-stepping, depressurization
📊 Physical Properties	Transport properties, interfacial tension
🛢️ PVT Simulation	Reservoir fluid characterization, tuning
🌊 Fluid Mechanics	Pipeline flow, multiphase modeling
🎯 Optimization	Production optimization, multi-objective, constraints
⚠️ Risk & Reliability	Equipment failure, Monte Carlo, SIS/SIF, bow-tie
🛡️ Safety Systems	ESD, HIPPS, PSV, blowdown, alarms
🌱 Emissions & Sustainability	CO₂, methane, nmVOC virtual measurement, Norwegian methods
💰 Cost Estimation	CAPEX, OPEX, financial metrics (NPV, ROI)
💡 Examples	Tutorials, Jupyter notebooks, code samples
🔧 Development	Contributing guidelines, developer setup

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📚 Interactive Reference Manual

The Interactive Reference Manual provides a searchable, navigable guide to all NeqSim packages:

✅ Complete package hierarchy

✅ Class and interface listings

✅ Usage examples and snippets

✅ Cross-referenced links

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🐍 Python Integration

NeqSim is also available for Python through neqsim-python:

from neqsim.thermo import TPflash, fluid

# Create and flash a natural gas
gas = fluid("srk")
gas.addComponent("methane", 0.9)
gas.addComponent("ethane", 0.1)
gas.setTemperature(298.15, "K")
gas.setPressure(50.0, "bara")

TPflash(gas)
print(f"Gas density: {gas.getDensity('kg/m3'):.2f} kg/m³")

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🔗 Resources

📦 GitHub Repository
Source code & issues ☕ Maven Central
Latest releases 🐛 Issue Tracker
Report bugs 💬 Discussions
Community Q&A

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NeqSim is developed and maintained by Equinor and contributors.

Licensed under the Apache 2.0 License.