title: Process Simulation Package description: The process package provides process equipment, unit operations, controllers, and process system management for building complete flowsheets. —

The process package provides process equipment, unit operations, controllers, and process system management for building complete flowsheets.

For controlled design cases, equipment and discipline sizing, safety verification, engineering deliverables, and handover, use the separate Engineering documentation.

Table of Contents

Overview

Location: neqsim.process

Purpose:

Documentation Structure

This documentation is organized into the following sections:

Section Description
equipment/ Equipment documentation (separators, compressors, etc.)
equipment/adsorption_bed.md Adsorption bed — transient simulation, LDF mass transfer, PSA/TSA cycles
lng_liquefaction.md LNG liquefaction — closed-loop SMR, C3MR, DMR, and nitrogen-expander templates with common KPIs and literature screening
mercury_removal.md Mercury removal guard beds — chemisorption (PuraSpec), bed loading, breakthrough, degradation, mechanical design, cost
bioprocessing.md Bio-processing — reactors, fermenters, solid-liquid separators, LLE, evaporators, dryers, crystallizers
neqsim-studio.md NeqSim Studio (Python) — newcomer-friendly process builder: natural language, templates, guided wizard, edit-by-chat, recipe gallery
processmodel/ ProcessSystem and flowsheet management
energy_streams.md Energy streams — typed heat, shaft-work, and electrical ports, unit-aware duties, graph ordering, and energy-driven equipment
process_json_export_and_e300_fluids.md Process JSON export — self-contained ProcessSystem/ProcessModel JSON for MCP, including E300-equivalent component properties and volume correction
simulation-hooks-and-events.md Lifecycle hooks, event bus, auto-validation for ProcessSystem and ProcessModel
model-change-events.md Governed model revisions — versioned change events, idempotent publication, fingerprints, and durable replay
model-impact-analysis.md Cross-model impact analysis — configurable propagation rules, recalculation order, cycle detection, and reapproval work
safety/ Safety systems (PSV, ESD, blowdown)
controllers.md Process controllers and logic
unisim-to-neqsim-conversion.md UniSim/HYSYS conversion — convert .usc models to NeqSim with E300 full-fluid transfer and export back to UniSim
piping_route_builder.md STID/E3D line-list piping route builder — convert route tables into serial Beggs-and-Brill hydraulic models and water-hammer screening handoffs
water_hammer_implementation.md Water hammer/liquid hammer screening — fast valve closure, pump trip, STID route, tagreader event, and MCP runWaterHammer workflow
operational_evidence_package.md Operational evidence package — combine P&ID/STID references, tagreader values, scenario actions, and bottleneck detection
exergy-analysis.md Exergy analysis — plant-wide destruction hotspots for ProcessSystem and ProcessModel
production-allocation.md Production allocation — back-allocate metered production to wells/sources via a linear recovery-factor proxy network (handles recycle/reflux)
k-value-fast-simulation.md Cached K-value fast simulation — run one rigorous base-case process, freeze separator K-values and fallback splits, then execute fast source-rate scenarios without repeated EOS flashes
screening_calculators.md Screening and sizing calculators — flare radiation (API 521), line sizing/erosion LOF (API RP 14E), flow-induced vibration (AVIFF), pump NPSH, control-valve sizing/noise (IEC 60534), thermowell strength (ASME PTC 19.3), pipeline overpressure protection, orifice metering (GPSA), and crude desalting; with optional process-object bridges

Process Design Guide

Document Description
process_design_guide.md Complete guide to process design workflow using NeqSim

Design Framework (NEW) ✨

Document Description
DESIGN_FRAMEWORK.md Automated equipment sizing and optimization framework

Key Features:

Optimization and Constraints Framework (NEW) ✨

Document Description
optimization/OPTIMIZATION_AND_CONSTRAINTS.md COMPREHENSIVE: Complete guide to optimization algorithms, constraint types, bottleneck analysis
optimization/OPTIMIZATION_OVERVIEW.md When to use which optimizer
optimization/process-researcher.md Process researcher - generate and rank candidate flowsheets from feed/product targets, including reaction routes
CAPACITY_CONSTRAINT_FRAMEWORK.md Equipment capacity limits and utilization tracking

Key Features:

Corrosion Analysis ✨

Document Description
corrosion/ Corrosion analysis module overview — NORSOK M-506 CO2 corrosion rate + NORSOK M-001 material selection
corrosion/norsok_m506_corrosion_rate.md NORSOK M-506 API — CO2 corrosion rate prediction with fugacity, pH, correction factors
corrosion/norsok_m001_material_selection.md NORSOK M-001 API — Material grade recommendation, sour service, chloride SCC
corrosion/pipeline_corrosion_integration.md Pipeline integration — Automated corrosion analysis from process simulation

Electrical Design Documentation

Document Description
electrical-design.md Electrical design framework — motor sizing, VFD, cable, transformer, switchgear, hazardous area, equipment-specific designs, plant-wide load analysis

Dynamic Simulation

Document Description
dynamic-simulation.md Dynamic simulation helper — auto-instruments a sized steady-state process with transmitters and PID controllers for transient simulation
agent-rca-dynamic-fault-benchmark.md AgentRCA dynamic fault benchmark — normal-only evidence and ranked diagnoses for controlled sensor bias, gas leaks, blockage, and imposed multiphase slugging excitation

Key Features:

Instrument Design Documentation

Document Description
instrument-design.md Instrument design framework — ISA-5.1 identification, SIL-rated safety instruments, I/O counting, DCS/SIS cabinet sizing, cost estimation, equipment-specific designs (separator, compressor, heat exchanger, pipeline, valve), plant-wide SystemInstrumentDesign

Key Features:

Mechanical Design Documentation

Document Description
EQUIPMENT_DESIGN_PARAMETERS.md Equipment design parameters, autoSize vs MechanicalDesign guide
mechanical_design_standards.md Design standards (NORSOK, ASME, API, DNV, etc.)
process_design_standards_program.md Standards priorities, evidence gates, requirement coverage, and change control
standard_design_kernel_migration.md Migrate global editions, metadata factories, mutable calculators, and legacy case execution to typed kernels
mechanical_design_database.md Data sources, database schemas, and CSV configuration
pipeline_mechanical_design.md Pipeline mechanical design (wall thickness, stress, buckling, corrosion)
dnv_rp_f109_on_bottom_stability.md DNV-RP-F109 on-bottom stability screening — typed vertical, transparent absolute-static lateral, and external-response displacement checks with fail-closed readiness
dnv_st_f101_pipeline_screening.md Fail-closed DNV-ST-F101:2021 pipeline limit-state screening with explicit review boundary
topside_piping_design.md Topside piping design (velocity, support, vibration per ASME B31.3)
riser_mechanical_design.md Riser design (catenary, VIV, fatigue per DNV-OS-F201)
well_mechanical_design.md Well casing/tubing design, barrier verification, cost estimation per NORSOK D-010, API 5CT
torg_integration.md Technical Requirements Documents (TORG) integration
field_development_orchestration.md Complete design workflow orchestration
mechanical_design/two_phase_heat_transfer.md Two-phase heat transfer — Shah condensation, Chen/Gungor-Winterton boiling, Friedel/MSH pressure drop, Ebert-Panchal fouling, incremental zone analysis, tube inserts

Cost Estimation Framework (NEW) ✨

Document Description
COST_ESTIMATION_FRAMEWORK.md Comprehensive capital and operating cost estimation, including scope-safe result reconciliation
COST_ESTIMATION_API_REFERENCE.md Detailed API reference for cost estimation classes and CostEstimateResult output maps

Key Features:

Equipment Categories

Category Documentation Classes
Streams streams.md Stream, EnergyStream, VirtualStream
Separators separators.md Separator, ThreePhaseSeparator, GasScrubber
Heat Exchangers heat_exchangers.md Heater, Cooler, HeatExchanger
Compressors compressors.md Compressor, CompressorChart, CompressorWashing
Compressor Deposit / Degradation compressor_deposit_degradation.md CompressorDeposit, DepositMechanism, DepositSource, CompressorDepositProfile, WashFluid, CompressorDepositWash
Compressor Anti-Surge Control compressor_antisurge_control.md AntiSurgeController, CompressorMonitor, ThrottlingValve, Recycle
Pumps pumps.md Pump, PumpChart
Expanders expanders.md Expander, TurboExpanderCompressor
Valves valves.md ThrottlingValve, SafetyValve, BlowdownValve
Choke Collapse Analysis choke-collapse.md ChokeCollapseAnalyzer — critical pressure ratio, flashing, cavitation
Inadvertent Valve Operation inadvertent-valve-operation.md InadvertentValveOperationAnalyzer — API 521 §4.4.13 / NORSOK P-002 IVO screening
Well Chokes well_choke_implementation.md Sachdeva, Gilbert choke models, ThrottlingValve integration
Distillation distillation.md DistillationColumn, SimpleTray
Absorbers absorbers.md SimpleAbsorber, SimpleTEGAbsorber
Ejectors ejectors.md Ejector
Membranes membranes.md MembraneSeparator
Flares flares.md Flare, FlareStack
Electrolyzers electrolyzers.md Electrolyzer, CO2Electrolyzer
Filters filters.md Particle, coalescing, strainer, and media filters with dynamic loading and mechanical design
H2S Scavengers H2S_scavenger_guide.md H2S chemical scavenging (triazine, glyoxal, iron sponge)
Sulfur Recovery sulfur_recovery.md Integrated Claus furnace, WHB, converters, sulfur condensers, TGTU recycle, incineration, and KPIs
Reactors reactors.md GibbsReactor
Pipelines pipelines.md Pipeline, AdiabaticPipe, TopsidePiping, Riser
Water Hammer Screening water_hammer_implementation.md WaterHammerPipe, WaterHammerStudy, MCP runWaterHammer
Piping Route Builder piping_route_builder.md PipingRouteBuilder for STID/E3D line-list route hydraulics
CO2 Well Analysis co2_injection_well_analysis.md CO2InjectionWellAnalyzer, ImpurityMonitor, TransientWellbore, CO2FlowCorrections
LNG Liquefaction lng_liquefaction.md LNGProcessBuilder, LNGProcessModel, LNGProcessBenchmark, LNGHeatExchanger
Hydrogen Production hydrogen_production.md SMR/ATR/POX route templates, ReformerFurnace, CatalyticTubeReformer, AutothermalReformer, PartialOxidationReactor, PSACascade, Electrolyzer
Looped Networks looped_networks.md LoopedPipeNetwork, Hardy Cross solver
Gas Network Operations gas_network_operations.md Conservative mixing, coupled hydraulics, quality, optimization, and linepack
Oil Network Operations oil_network_operations.md Pumps, assays, tanks, parcels, blends, and cargo scheduling
Tanks tanks.md Tank, VesselDepressurization
Wells wells.md Well equipment
Subsea Trees subsea_trees.md SubseaTree, valve control
Subsea Manifolds subsea_manifolds.md SubseaManifold
Subsea Boosters subsea_boosters.md SubseaBooster, multiphase pumps
Umbilicals umbilicals.md Umbilical systems
Battery Storage battery_storage.md BatteryStorage
Heat Integration heat_integration.md PinchAnalysis, HeatStream
Power Generation power_generation.md GasTurbine, SteamTurbine, HRSG, CombinedCycleSystem, FuelCell, WindTurbine, SolarPanel
Failure Modes failure_modes.md EquipmentFailureMode, reliability
Mixers/Splitters mixers_splitters.md Mixer, Splitter
Utility util/ Adjuster, Recycle, Calculator

Package Architecture

The process package separates common simulation behavior from equipment-specific stream topology. Use the narrowest API that represents the operation being modeled.

Responsibility Current API Boundary
Simulation lifecycle SimulationInterface, SimulationBaseClass Execution identity, run state, and common simulation behavior
Equipment contract ProcessEquipmentInterface Reporting, mechanical design, validation, fluid access, capacity, and common operating properties
Shared equipment implementation ProcessEquipmentBaseClass Common state and default implementations; it does not imply one inlet and one outlet
One-inlet/one-outlet equipment TwoPortInterface, TwoPortEquipment Single-stream inlet/outlet methods used by heaters, compressors, pumps, and throttling valves
Multiport equipment Equipment-specific classes Separators, mixers, splitters, and columns expose topology-specific stream methods
Flowsheet orchestration ProcessSystem Named units, topology, execution strategy, convergence, reporting, and transient time
Controls and measurements controllerdevice, measurementdevice, logic Controllers, sensors, alarms, and process logic

See the equipment index for the current category map and ProcessSystem guide for orchestration details.

ProcessSystem

The ProcessSystem class is the container for building and running process flowsheets.

Basic Usage

The following complete Java 8 program builds and runs a valve-and-separator flowsheet. run() is the normal entry point; with the default settings it delegates to the topology-aware optimized dispatcher and falls back conservatively when parallel execution is not suitable.

import neqsim.process.equipment.separator.Separator;
import neqsim.process.equipment.stream.Stream;
import neqsim.process.equipment.valve.ThrottlingValve;
import neqsim.process.processmodel.ProcessSystem;
import neqsim.thermo.system.SystemInterface;
import neqsim.thermo.system.SystemSrkEos;

public final class ProcessSystemQuickStart {
  private ProcessSystemQuickStart() {}

  public static void main(String[] args) {
    SystemInterface fluid = new SystemSrkEos(300.0, 80.0);
    fluid.addComponent("methane", 0.85);
    fluid.addComponent("ethane", 0.08);
    fluid.addComponent("propane", 0.05);
    fluid.addComponent("n-butane", 0.02);
    fluid.setMixingRule("classic");

    Stream feed = new Stream("feed", fluid);
    feed.setFlowRate(1000.0, "kg/hr");

    ThrottlingValve valve = new ThrottlingValve("inlet valve", feed);
    valve.setOutletPressure(40.0, "bara");

    Separator separator = new Separator("HP separator", valve.getOutletStream());

    ProcessSystem process = new ProcessSystem("gas processing plant");
    process.add(feed);
    process.add(valve);
    process.add(separator);
    process.run();

    double inletMassFlowKgPerHr = feed.getFlowRate("kg/hr");
    double gasMassFlowKgPerHr = separator.getGasOutStream().getFlowRate("kg/hr");
    double liquidMassFlowKgPerHr =
        separator.getLiquidOutStream().getFlowRate("kg/hr");
    double relativeMassBalanceError =
        Math.abs(
                inletMassFlowKgPerHr
                    - gasMassFlowKgPerHr
                    - liquidMassFlowKgPerHr)
            / inletMassFlowKgPerHr;

    if (!(gasMassFlowKgPerHr > 0.0)
        || relativeMassBalanceError > 1.0e-6) {
      throw new IllegalStateException("Invalid separator result");
    }

    if (process.hasRecycleLoops()
        || process.getExecutionPartitionInfo().isEmpty()
        || process.getReport_json().isEmpty()
        || process.getStreamSummaryTable().isEmpty()) {
      throw new IllegalStateException("Incomplete process diagnostics");
    }
  }
}

Execution Strategies

Use run() for normal simulations. By default, it delegates to runOptimized(), which selects a strategy from the current topology:

runParallel() is a lower-level API, throws InterruptedException, and should be called directly only when the caller deliberately owns interruption handling. The public hybrid entry point is runHybrid(UUID), not a no-argument method. Do not assume a fixed speedup: execution time depends on topology, unit-operation cost, recycle behavior, runtime, and hardware. Benchmark representative cases and confirm that results match the sequential baseline.

Analyze Process Topology

Use hasRecycleLoops() to detect cycles and getExecutionPartitionInfo() to inspect the topology-derived execution plan. The complete quick start above executes both calls.

Key ProcessSystem Methods

Method Description
add(equipment) Add equipment to the process
run() Run using the configured default; optimized dispatch is enabled by default
runOptimized() Select a conservative strategy from the current topology
runParallel() Run independent graph levels in parallel; throws InterruptedException
runHybrid(UUID) Low-level hybrid execution for recycle-containing systems
runTransient() Advance one transient step using the configured time step
getUnit(name) Get equipment by name
hasRecycleLoops() Check whether the process graph contains cycles
getExecutionPartitionInfo() Describe the current execution partition
copy() Deep-copy the process system
getReport_json() Generate the structured JSON report
getStreamSummaryTable() Return a formatted stream-property table

Choosing Equipment

The equipment index is the authoritative navigation page for individual unit-operation guides. The complete quick start above is the canonical package example; individual guides add equipment-specific constructors, specifications, units, and validation.

Stream topology determines which accessor is valid:

Topology Examples Access pattern
One inlet, one outlet Heater, compressor, pump, throttling valve TwoPortEquipment.getInletStream() and getOutletStream()
Multiple outlets Separator, splitter Equipment-specific getters such as Separator.getGasOutStream() and getLiquidOutStream()
Multiple inlets Mixer, separator Equipment-specific addStream(...) or inlet-list APIs
Staged equipment Distillation column, absorber Stage/feed APIs plus equipment-specific product streams
Utility graph node Recycle, adjuster, calculator Declared input/output dependencies rather than a universal material outlet

Do not cast the result of ProcessSystem.getUnit(name) until the expected equipment type has been established. Prefer retaining a typed reference when constructing the flowsheet.

Specifications, Recycles, and Calculators

A focused calculator callback looks like this when stream and heater are already typed objects in the same running flowsheet:

Calculator calc = new Calculator("heater target calculator");
calc.addInputVariable(stream);
calc.setOutputVariable(heater);
calc.setCalculationMethod((inputs, output) -> {
    Stream feed = (Stream) inputs.get(0);
    Heater target = (Heater) output;
    target.setOutTemperature(feed.getTemperature("K") + 10.0, "K");
});
process.add(calc);

The calculator guide supplies the imports, complete executable context, supported presets, setter targets, and recycle-coupling boundaries.

Transient and Safety Boundaries

A steady-state flowsheet is not automatically a valid dynamic model. Before advancing time:

  1. converge and validate the steady-state case;
  2. confirm that each participating unit implements the required transient state and holdup;
  3. choose a time step appropriate for the fastest modeled response;
  4. configure controllers, events, and boundary conditions explicitly;
  5. call runTransient(double, UUID) when the caller needs explicit step duration and calculation identity, or the configured no-argument helper when that behavior is intentional;
  6. capture results through reports, monitors, or callbacks rather than console printing.

See dynamic simulation for instrumentation and controller setup.

A SafetyValve is constructed from a StreamInterface, not a vessel object, and its current set-pressure method is setPressureSpec(double); there is no setSetPressure(...) API. Pressure-relief simulation is not design certification. Use the valve guide and safety roadmap, record units and scenarios explicitly, and obtain the required engineering review.

Result Handling

After a successful run:

The legacy reportResults() aggregator assumes every equipment type supplies a non-null row array and is not a general flowsheet reporting contract. Treat interactive display helpers as diagnostic UI, not serialized evidence.

Best Practices

  1. Give every stream, equipment object, controller, and measurement a stable unique name.
  2. Set feed composition, flow basis, temperature, and pressure with explicit units.
  3. Retain typed object references and add units to the ProcessSystem in readable flow order.
  4. Use graph-aware recycle, adjuster, and calculator objects instead of manual outer loops.
  5. Validate mass and energy balances, convergence, phase behavior, and operating constraints.
  6. Clone a stream before intentional branching when downstream cases must not share mutable state.
  7. Preserve the ProcessSystem, named streams, calculation identity, and structured reports when the model will be serialized, restarted, or embedded in a larger workflow.

Future Infrastructure

NeqSim includes foundational infrastructure to support the future of process simulation:

Capability Documentation Description
Lifecycle Management lifecycle/ Model versioning, state export/import, lifecycle tracking
Emissions Tracking sustainability/ CO2e accounting, regulatory reporting
Advisory Systems advisory/ Look-ahead predictions with uncertainty
ML Integration ml/ Surrogate models, physics constraint validation
Safety Scenarios safety/scenario-generation.md Automatic failure scenario generation
Batch Studies optimization/batch-studies.md Parallel parameter studies

See Future Infrastructure Overview for complete documentation.