Reactors

NeqSim provides a family of reactor models for gas-phase kinetics, chemical equilibrium, stoichiometric conversion, catalytic reactions, and bio-processing. All reactors live in the neqsim.process.equipment.reactor package and integrate with ProcessSystem flowsheets.

Table of Contents

Overview

Package: neqsim.process.equipment.reactor

Class Description
PlugFlowReactor Tubular reactor with ODE-based kinetics, catalyst bed, pressure drop
KineticReaction Rate expression (power-law, LHHW, reversible Arrhenius)
CatalystBed Packed bed properties, Ergun pressure drop, Thiele modulus
ReactorAxialProfile Axial position profiles with interpolation and export
StirredTankReactor Continuous stirred tank reactor (CSTR)
GibbsReactor Gibbs free energy minimization for equilibrium
GibbsReactorCO2 Gibbs reactor variant specialized for CO2 reactions
StoichiometricReaction Fixed-conversion stoichiometric reactor
AmmoniaSynthesisReactor Specialized reactor for ammonia synthesis
SulfurDepositionAnalyser Sulfur solubility, deposition onset, corrosion assessment
FurnaceBurner Fired heater / furnace burner
Fermenter Fermentation reactor for bio-processing
EnzymeTreatment Enzyme-based treatment reactor

Reactor Selection Guide

Reactor When to Use
PlugFlowReactor Gas-phase catalytic or homogeneous reactions with axial gradients
StirredTankReactor Liquid-phase reactions, good mixing, residence time calculations
GibbsReactor Complex equilibrium without specifying reaction stoichiometry
StoichiometricReaction Known fixed conversion, simple material balance
AmmoniaSynthesisReactor Haber-Bosch ammonia synthesis modeling
SulfurDepositionAnalyser Sulfur precipitation, H2S reactions, corrosion assessment

Plug Flow Reactor (PFR)

The PlugFlowReactor is the most comprehensive reactor in NeqSim. It solves coupled ODEs for species molar flows, temperature, and pressure as a function of axial position.

Key features:

Quick Example

import neqsim.thermo.system.SystemSrkEos;
import neqsim.process.equipment.stream.Stream;
import neqsim.process.equipment.reactor.PlugFlowReactor;
import neqsim.process.equipment.reactor.KineticReaction;
import neqsim.process.equipment.reactor.CatalystBed;

// Feed gas
SystemSrkEos gas = new SystemSrkEos(273.15 + 300.0, 20.0);
gas.addComponent("methane", 0.90);
gas.addComponent("ethane", 0.10);
gas.setMixingRule("classic");

Stream feed = new Stream("Feed", gas);
feed.setFlowRate(10.0, "mole/sec");
feed.run();

// Reaction: methane -> ethane (illustrative)
KineticReaction rxn = new KineticReaction("A to B");
rxn.addReactant("methane", 1.0, 1.0);
rxn.addProduct("ethane", 1.0);
rxn.setPreExponentialFactor(1.0e4);
rxn.setActivationEnergy(50000.0);
rxn.setHeatOfReaction(-50000.0);

// Catalyst
CatalystBed catalyst = new CatalystBed(3.0, 0.40, 800.0);

// Reactor
PlugFlowReactor pfr = new PlugFlowReactor("PFR-1", feed);
pfr.addReaction(rxn);
pfr.setCatalystBed(catalyst);
pfr.setLength(5.0, "m");
pfr.setDiameter(0.10, "m");
pfr.setEnergyMode(PlugFlowReactor.EnergyMode.ADIABATIC);
pfr.setNumberOfSteps(100);
pfr.setKeyComponent("methane");
pfr.run();

System.out.println("Conversion: " + pfr.getConversion());
System.out.println("Outlet T: " + (pfr.getOutletTemperature() - 273.15) + " C");
System.out.println("Pressure drop: " + pfr.getPressureDrop() + " bar");

Full documentation: See the Plug Flow Reactor Guide for governing equations, all kinetic models, LHHW setup, coolant mode, multi-tube reactors, Python usage, and the complete API reference.

Stirred Tank Reactor (CSTR)

The StirredTankReactor models a continuous stirred tank reactor with perfect mixing.

import neqsim.process.equipment.reactor.StirredTankReactor;

StirredTankReactor cstr = new StirredTankReactor("R-100", feedStream);
cstr.run();

Gibbs Reactor

Minimizes Gibbs free energy to find equilibrium composition without requiring explicit reaction stoichiometry. Uses Newton-Raphson iteration with element balance constraints.

import neqsim.process.equipment.reactor.GibbsReactor;

// Feed must include all possible product species (even at zero mole fraction)
SystemSrkEos gas = new SystemSrkEos(273.15 + 800.0, 20.0);
gas.addComponent("methane", 1.0);
gas.addComponent("water", 3.0);
gas.addComponent("CO", 1.0e-10);
gas.addComponent("CO2", 1.0e-10);
gas.addComponent("hydrogen", 1.0e-10);
gas.setMixingRule("classic");

Stream feed = new Stream("Feed", gas);
feed.setFlowRate(100.0, "kmol/hr");
feed.run();

GibbsReactor gibbs = new GibbsReactor("SMR Reactor", feed);
gibbs.run();

Key methods:

See GibbsReactor Reference Documentation for the full mathematical foundation, algorithm details, and usage examples.

Stoichiometric Reactor

Fixed-conversion reactor based on specified stoichiometry.

import neqsim.process.equipment.reactor.StoichiometricReaction;

StoichiometricReaction stoich = new StoichiometricReaction("R-Stoich", feedStream);
stoich.run();

Ammonia Synthesis Reactor

Specialized reactor for the Haber-Bosch process (N2 + 3 H2 ⇌ 2 NH3).

import neqsim.process.equipment.reactor.AmmoniaSynthesisReactor;

AmmoniaSynthesisReactor nh3 = new AmmoniaSynthesisReactor("NH3-Reactor", feedStream);
nh3.run();

Sulfur Deposition Analyser

Analyses sulfur solubility, deposition onset temperature, chemical equilibrium of H2S/O2 reactions, corrosion (FeS formation), and blockage risk. Performs temperature sweep analysis.

import neqsim.process.equipment.reactor.SulfurDepositionAnalyser;

SulfurDepositionAnalyser analyser = new SulfurDepositionAnalyser("S-Analyser", feedStream);
analyser.setTemperatureSweepRange(0.0, 200.0, 5.0);
analyser.setRunChemicalEquilibrium(true);
analyser.setRunSolidFlash(true);
analyser.setRunCorrosionAssessment(true);
analyser.run();

double onset = analyser.getSulfurDepositionOnsetTemperature();
String json = analyser.getResultsAsJson();

Furnace Burner

Models a fired heater / furnace burner for high-temperature heating.

import neqsim.process.equipment.reactor.FurnaceBurner;

FurnaceBurner burner = new FurnaceBurner("Furnace", feedStream);
burner.run();

Bio-Processing Reactors

Fermenter

Models a biological fermentation reactor.

import neqsim.process.equipment.reactor.Fermenter;

Fermenter fermenter = new Fermenter("BioReactor", feedStream);
fermenter.run();

Enzyme Treatment

Models an enzyme-based treatment step.

import neqsim.process.equipment.reactor.EnzymeTreatment;

EnzymeTreatment enzyme = new EnzymeTreatment("EnzymeUnit", feedStream);
enzyme.run();