Getting Started with Process Optimization

This page is a practical starting point for process optimization in NeqSim.

1) Choose optimization API

Use case API
Maximize throughput at fixed inlet/outlet pressure ProcessOptimizationEngine
Custom objective and/or multiple decision variables ProductionOptimizer
Pareto optimization (throughput vs. power, etc.) MultiObjectiveOptimizer
Constrained NLP (equality + inequality) SQPoptimizer
Automate set/get variables by string addresses ProcessAutomation

2) Build and run a base process first

ProcessSystem process = new ProcessSystem();
// ... add streams/equipment
process.run();

Always run the base case before optimization.

3) Throughput optimization with ProcessOptimizationEngine

import neqsim.process.util.optimizer.ProcessOptimizationEngine;
import neqsim.process.util.optimizer.ProcessOptimizationEngine.OptimizationResult;

ProcessOptimizationEngine engine = new ProcessOptimizationEngine(process);

OptimizationResult result = engine.findMaximumThroughput(
    50.0,    // inlet pressure [bara]
    10.0,    // outlet pressure [bara]
    1000.0,  // min flow [kg/hr]
    100000.0 // max flow [kg/hr]
);

System.out.println("Max flow: " + result.getOptimalValue() + " kg/hr");
System.out.println("Bottleneck: " + result.getBottleneck());

4) Check utilization for all equipment types (core optimization signal)

NeqSim optimization is constraint-driven. Utilization is the shared metric across equipment strategies (compressors, separators, pumps, valves, heat exchangers, reactors, distillation, tanks, expanders, ejectors, subsea equipment, and more).

import java.util.Map;

// Process-level utilization summary: equipment name -> utilization percentage
Map<String, Double> util = process.getCapacityUtilizationSummary();
for (Map.Entry<String, Double> e : util.entrySet()) {
  System.out.printf("%s: %.1f%%%n", e.getKey(), e.getValue());
}

System.out.println("Bottleneck unit: " + process.findBottleneck().getEquipmentName());
System.out.println("Any overloaded? " + process.isAnyEquipmentOverloaded());

This is directly connected to optimization because ProcessOptimizationEngine and ProductionOptimizer accept/reject candidates using these utilization constraints.

You can also inspect full reports from the optimization engine:

ProcessOptimizationEngine.ConstraintReport report = engine.evaluateAllConstraints();
System.out.println("Overall utilization: " + report.getOverallUtilization() * 100.0 + "%");

5) Custom optimization with ProductionOptimizer

import java.util.Arrays;
import java.util.List;
import neqsim.process.util.optimizer.ProductionOptimizer;
import neqsim.process.util.optimizer.ProductionOptimizer.ObjectiveType;
import neqsim.process.util.optimizer.ProductionOptimizer.OptimizationConfig;
import neqsim.process.util.optimizer.ProductionOptimizer.OptimizationObjective;
import neqsim.process.util.optimizer.ProductionOptimizer.OptimizationResult;
import neqsim.process.util.optimizer.ProductionOptimizer.SearchMode;

ProductionOptimizer optimizer = new ProductionOptimizer();

OptimizationConfig config = new OptimizationConfig(50000.0, 200000.0)
    .tolerance(100.0)
    .searchMode(SearchMode.GOLDEN_SECTION_SCORE)
    .maxIterations(30);

List<OptimizationObjective> objectives = Arrays.asList(
    new OptimizationObjective(
        "throughput",
        proc -> proc.getUnit("outlet").getFlowRate("kg/hr"),
        1.0,
        ObjectiveType.MAXIMIZE)
);

OptimizationResult result = optimizer.optimize(process, feed, config, objectives, null);
System.out.println("Optimal rate: " + result.getOptimalRate() + " kg/hr");

6) ProcessModel and automation loop

Use ProcessAutomation for robust, string-addressed optimization loops in both ProcessSystem and multi-area ProcessModel.

import neqsim.process.automation.ProcessAutomation;

ProcessAutomation auto = process.getAutomation();
auto.setVariableValue("Compressor.outletPressure", 120.0, "bara");
process.run();
double powerMW = auto.getVariableValue("Compressor.power", "MW");

// Multi-area ProcessModel
ProcessAutomation plantAuto = plant.getAutomation();
double tC = plantAuto.getVariableValue("Separation::HP Sep.gasOutStream.temperature", "C");
plantAuto.setVariableValue("Compression::Compressor.outletPressure", 170.0, "bara");
plant.run();
  1. Run base case: process.run().
  2. (Optional) auto-size equipment.
  3. Run again after sizing.
  4. Optimize.
  5. Review utilization report and bottlenecks.
  6. Apply operational constraints and re-run.

8) Next reading