Comparing process simulations with NeqSim (Java)

This guide shows how to reproduce the comparesimulations.ipynb Colab notebook using only the Java API. It walks through building the feed, assembling the flowsheet, running the model, and exporting a JSON report so you can align the results with HYSYS/DWSIM or other tools.

Prerequisites

Step-by-step Java example

import neqsim.process.equipment.compressor.Compressor;
import neqsim.process.equipment.separator.ThreePhaseSeparator;
import neqsim.process.equipment.stream.Stream;
import neqsim.process.processmodel.ProcessModel;
import neqsim.process.processmodel.ProcessSystem;
import neqsim.process.util.report.Report;
import neqsim.thermo.system.SystemInterface;
import neqsim.thermo.system.SystemSrkEos;

// 1) Build the feed to mirror the notebook composition
SystemInterface wellFluid = new SystemSrkEos(310.0, 50.0); // T=310 K, p=50 bara
wellFluid.addComponent("methane", 0.8);
wellFluid.addComponent("ethane", 0.1);
wellFluid.addComponent("propane", 0.05);
wellFluid.addComponent("n-butane", 0.05);
wellFluid.initProperties();

// 2) Create the inlet process section (stream + three-phase separator)
Stream wellStreamHP = new Stream("HP well stream", wellFluid);
wellStreamHP.setFlowRate(10.0, "MSm3/day");
ThreePhaseSeparator firstStageSeparator =
    new ThreePhaseSeparator("1st stage separator", wellStreamHP);

ProcessSystem inletSection = new ProcessSystem();
inletSection.add(wellStreamHP);
inletSection.add(firstStageSeparator);

// 3) Create the compressor section using the separator gas outlet
Stream compressorFeed = firstStageSeparator.getGasOutStream();
Compressor compressor1 = new Compressor("Compressor1", compressorFeed);
compressor1.setPolytropicEfficiency(0.56);
compressor1.setUsePolytropicCalc(true);
compressor1.setOutletPressure(100.0, "bara");

ProcessSystem compressorSection = new ProcessSystem();
compressorSection.add(compressorFeed);
compressorSection.add(compressor1);

// 4) Combine the sections in a ProcessModel and run them sequentially
ProcessModel combinedProcess = new ProcessModel();
combinedProcess.add("feed process", inletSection);
combinedProcess.add("compressor process", compressorSection);
combinedProcess.setRunStep(true); // ensures each section runs in the order added
combinedProcess.run();

// 5) Read results or export the JSON report used for cross-tool comparison
System.out.printf("Gas flow after separator: %.3f MSm3/day%n",
    firstStageSeparator.getGasOutStream().getFlowRate("MSm3/day"));
System.out.printf("Compressor outlet temperature: %.2f C%n",
    compressor1.getOutletStream().getTemperature("C"));

Report reporter = new Report(combinedProcess);
String jsonReport = reporter.generateJsonReport();
System.out.println(jsonReport);

Tips when translating the notebook to Java: