neqsim-heat-integration

NeqSim Heat Integration Skill

Linnhoff-method pinch analysis to determine minimum hot/cold utility duties, the pinch temperature, composite & grand-composite curves, and to evaluate heat-exchanger network (HEN) opportunities.

When to Use

• Determining MER (Minimum Energy Requirement) for a flowsheet
• Setting utility duties before equipment sizing
• Retrofit analysis — quantify potential savings vs. existing HEN
• Comparing process alternatives on energy footprint
• Sizing utility headers (steam, cooling water) consistently across a plant

Standard reference: B. Linnhoff & E. Hindmarsh (1983), Chem. Eng. Sci.; operational guidance from Smith — Chemical Process Design and Integration (2nd ed.).

Core Concept

Hot streams (need cooling)  ──┐
                              ├── shifted by ΔTmin/2 → temperature intervals → cascade → MER
Cold streams (need heating) ──┘

The pinch divides the system in two:

• Above pinch — heat sink (only hot utility allowed)
• Below pinch — heat source (only cold utility allowed)
• Across pinch — every kW transferred costs 1 kW hot + 1 kW cold

Three golden rules — never violate any of them:

1. No external heating below the pinch
2. No external cooling above the pinch
3. No heat transfer across the pinch

Pattern 1 — Streams Defined Manually

import neqsim.process.equipment.heatexchanger.heatintegration.PinchAnalysis;

PinchAnalysis pinch = new PinchAnalysis(10.0);   // ΔTmin in °C
// addHotStream(name, supplyT_C, targetT_C, mCp_kW_per_K)
pinch.addHotStream("H1 — reactor effluent",  180.0,  80.0, 30.0);
pinch.addHotStream("H2 — flash gas",         150.0,  50.0, 15.0);
pinch.addColdStream("C1 — feed preheat",      30.0, 140.0, 20.0);
pinch.addColdStream("C2 — reboiler feed",     60.0, 120.0, 25.0);
pinch.run();

double Qh   = pinch.getMinimumHeatingUtility();    // kW
double Qc   = pinch.getMinimumCoolingUtility();    // kW
double Tpinch = pinch.getPinchTemperatureC();

Pattern 2 — Auto-Extract from a ProcessSystem