Process Logic and Scenario Simulation Enhancements

This document describes the enhancements made to the NeqSim process logic framework to support advanced safety system simulation with logic sequences and scenario testing.

New Core Components Added

1. Logic Actions (src/main/java/neqsim/process/logic/action/)

SetValveOpeningAction.java

• Sets throttling valve to specific opening percentage (0-100%)
• Considers action complete when within 1% of target
• Used for controlled valve positioning

OpenValveAction.java

• Fully opens a throttling valve (100% opening)
• Simple action for emergency or startup valve opening
• Considers complete when >95% open

CloseValveAction.java

• Fully closes a throttling valve (0% opening)
• Simple action for emergency valve closure
• Considers complete when <5% open

SetSeparatorModeAction.java

• Switches separator between steady-state and transient calculation modes
• Critical for dynamic process simulation during upsets
• Instantaneous action

2. Logic Conditions (src/main/java/neqsim/process/logic/condition/)

ValvePositionCondition.java

• Monitors valve opening percentage with comparison operators
• Supports >, >=, <, <=, ==, != with configurable tolerance
• Essential for startup permissives and safety interlocks

3. Scenario Execution Framework (src/main/java/neqsim/process/util/scenario/)

ProcessScenarioRunner.java

• Coordinates process system simulation with logic execution
• Applies ProcessSafetyScenario perturbations automatically
• Provides real-time monitoring and status reporting
• Handles multiple logic sequences concurrently
• Integrates with transient simulation framework

ScenarioExecutionSummary.java

• Captures complete scenario execution results
• Tracks logic sequence final states and status descriptions
• Records errors, warnings, and performance metrics
• Enables automated testing and validation

Enhanced PushButton Integration

The existing PushButton class already supported linking to multiple ProcessLogic sequences via the linkToLogic() method, enabling:

• Manual ESD activation
• Startup sequence initiation
• Multi-logic coordination from single operator action

Example Implementation

ProcessLogicIntegratedExample.java

This comprehensive example demonstrates:

1. Process System Construction
   • High-pressure gas separation process
   • Safety valves, blowdown systems, and flare
   • Complete instrumentation setup
2. ESD Logic Implementation

   ESDLogic esdLogic = new ESDLogic("ESD Level 1");
   esdLogic.addAction(new CloseValveAction(inletValve), 0.0);
   esdLogic.addAction(new SetSplitterAction(gasSplitter, new double[]{0.0, 1.0}), 0.5);
   esdLogic.addAction(new ActivateBlowdownAction(bdValve), 0.5);
   esdLogic.addAction(new SetSeparatorModeAction(separator, false), 1.0);
   

3. Startup Logic with Permissives

   StartupLogic startupLogic = new StartupLogic("System Startup");
   startupLogic.addPermissive(new PressureCondition(separator, 5.0, "<"));
   startupLogic.addPermissive(new ValvePositionCondition(bdValve, "<", 5.0));
   startupLogic.addPermissive(new TimerCondition(10.0));
   

4. Scenario Testing

   ProcessScenarioRunner runner = new ProcessScenarioRunner(processSystem);
   runner.addLogic(esdLogic);
   runner.addLogic(startupLogic);
      
   ProcessSafetyScenario scenario = ProcessSafetyScenario.builder("High Pressure")
       .customManipulator("HP Feed", stream -> stream.setPressure(70.0, "bara"))
       .build();
      
   runner.runScenario("High Pressure Test", scenario, 60.0, 1.0);
   

Key Benefits

1. Reusable Components

• All logic actions and conditions are reusable across different examples
• ProcessScenarioRunner can be used for any process system
• Standard patterns for safety system implementation

2. Comprehensive Testing

• Automated scenario execution with perturbation application
• Real-time monitoring of logic sequence states
• Detailed execution summaries for validation

3. Safety System Integration

• Multi-layer protection (ESD, startup permissives, PSV)
• Proper sequencing with timing delays
• Automatic mode switching for dynamic simulation

4. Industry Best Practices

• Follows IEC 61511 safety lifecycle concepts
• Implements defense-in-depth protection philosophy
• Supports SIL (Safety Integrity Level) classifications

Usage Patterns

Basic ESD Implementation

ESDLogic esd = new ESDLogic("Emergency Shutdown");
esd.addAction(new CloseValveAction(inletValve), 0.0);
esd.addAction(new ActivateBlowdownAction(blowdownValve), 1.0);
pushButton.linkToLogic(esd);

Startup with Permissives

StartupLogic startup = new StartupLogic("Safe Startup");
startup.addPermissive(new PressureCondition(vessel, 2.0, "<"));
startup.addPermissive(new TemperatureCondition(vessel, 40.0, "<"));
startup.addPermissive(new TimerCondition(30.0));
startup.addAction(new OpenValveAction(feedValve), 0.0);

Scenario Testing

ProcessScenarioRunner runner = new ProcessScenarioRunner(system);
runner.addLogic(esdLogic);

ProcessSafetyScenario overpressure = ProcessSafetyScenario.builder("Overpressure")
    .customManipulator("Feed", s -> s.setPressure(80.0, "bara"))
    .build();

ScenarioExecutionSummary result = runner.runScenario("Test", overpressure, 120.0, 1.0);

Future Enhancements

The framework is designed for easy extension:

• Additional logic actions (pump control, compressor sequencing)
• More sophisticated conditions (flow rate trending, multi-variable)
• Advanced scenario types (Monte Carlo analysis, optimization)
• Integration with external safety systems
• Real-time process historian connectivity

This implementation provides a solid foundation for complex process safety simulation while maintaining the clean architecture and patterns established in the NeqSim framework.