Water Cooler and Reboiler

Documentation for specialized heat exchangers: WaterCooler for seawater/cooling water systems and ReBoiler for distillation column reboilers.

Table of Contents

Water Cooler

Location: neqsim.process.equipment.heatexchanger.WaterCooler

The WaterCooler class models process coolers using seawater or cooling water, with automatic calculation of cooling water flow rate using IAPWS IF97 steam tables.

Features

Java Example

import neqsim.process.equipment.heatexchanger.WaterCooler;

// Create process stream to be cooled
Stream hotStream = new Stream("Hot Process Gas", processFluid);
hotStream.setTemperature(120.0, "C");
hotStream.setFlowRate(5000.0, "kg/hr");
hotStream.run();

// Create water cooler
WaterCooler cooler = new WaterCooler("E-201", hotStream);

// Set process side outlet temperature
cooler.setOutTemperature(40.0, "C");

// Configure cooling water conditions
cooler.setWaterInletTemperature(15.0, "C");    // Seawater inlet
cooler.setWaterOutletTemperature(25.0, "C");   // Seawater outlet
cooler.setWaterPressure(3.0, "bara");          // Cooling water pressure

cooler.run();

// Get results
double duty = -cooler.getDuty() / 1000.0;  // kW (negative for cooling)
double cwFlow = cooler.getCoolingWaterFlowRate("kg/hr");

System.out.println("Cooling duty: " + duty + " kW");
System.out.println("Cooling water flow: " + cwFlow + " kg/hr");

Python Example

from neqsim import jneqsim

WaterCooler = jneqsim.process.equipment.heatexchanger.WaterCooler

# Create water cooler
cooler = WaterCooler("E-201", hot_stream)
cooler.setOutTemperature(40.0, "C")

# Configure cooling water
cooler.setWaterInletTemperature(15.0, "C")
cooler.setWaterOutletTemperature(25.0, "C")
cooler.setWaterPressure(3.0, "bara")

cooler.run()

print(f"Duty: {-cooler.getDuty()/1000:.1f} kW")
print(f"CW flow: {cooler.getCoolingWaterFlowRate('kg/hr'):.0f} kg/hr")

Calculation Basis

The cooling water flow rate is calculated using IAPWS IF97:

\[\dot{m}_{cw} = \frac{Q}{h_{out} - h_{in}}\]

Where:

Typical Applications

Application CW Inlet (°C) CW Outlet (°C) Notes
Seawater (North Sea) 4-12 20-30 Seasonal variation
Seawater (Gulf) 25-32 35-45 Higher temperatures
Cooling tower 25-30 35-40 Closed loop
River water 10-20 25-35 Environmental limits

Reboiler

Location: neqsim.process.equipment.heatexchanger.ReBoiler

The ReBoiler class provides heat input to distillation column bottoms through enthalpy addition (PH flash calculation).

Features

Java Example

import neqsim.process.equipment.heatexchanger.ReBoiler;

// Get bottoms stream from column
Stream columnsBottoms = column.getBottomsStream();

// Create reboiler
ReBoiler reboiler = new ReBoiler("Reboiler", columnsBottoms);
reboiler.setReboilerDuty(500000.0);  // 500 kW in Watts

reboiler.run();

// Get outlet conditions
double outletTemp = reboiler.getOutletStream().getTemperature("C");
double vaporFraction = reboiler.getOutletStream().getFluid().getVaporFraction();

System.out.println("Reboiler outlet temperature: " + outletTemp + " °C");
System.out.println("Vapor fraction: " + vaporFraction);

Python Example

from neqsim import jneqsim

ReBoiler = jneqsim.process.equipment.heatexchanger.ReBoiler

# Create reboiler on column bottoms
reboiler = ReBoiler("Reboiler", column.getBottomsStream())
reboiler.setReboilerDuty(500000.0)  # Watts

reboiler.run()

outlet = reboiler.getOutletStream()
print(f"Outlet T: {outlet.getTemperature('C'):.1f} °C")
print(f"Vapor fraction: {outlet.getFluid().getVaporFraction():.3f}")

Calculation Method

The reboiler performs a PH flash:

  1. Calculate inlet enthalpy
  2. Add reboiler duty to enthalpy
  3. Flash at constant pressure to find outlet T and phase split
\[H_{out} = H_{in} + Q_{reboiler}\]

Integration with Distillation Column

// Create distillation column with reboiler
DistillationColumn column = new DistillationColumn("Debutanizer", 20, true, true);
column.addFeedStream(feedStream, 10);

// Access internal reboiler
Reboiler columnReboiler = column.getReboiler();
columnReboiler.setReboilerDuty(duty);

// Or use separate reboiler equipment
Stream bottoms = column.getLiquidOutStream();
ReBoiler externalReboiler = new ReBoiler("Thermosiphon", bottoms);
externalReboiler.setReboilerDuty(calculatedDuty);

API Reference

WaterCooler

Constructors

Constructor Description
WaterCooler(String name) Create cooler with name
WaterCooler(String name, StreamInterface inStream) Create with inlet stream

Configuration Methods

Method Description
setWaterInletTemperature(double, String) Set CW inlet temperature
setWaterOutletTemperature(double, String) Set CW outlet temperature
setWaterPressure(double, String) Set CW pressure
setOutTemperature(double, String) Set process outlet temperature

Results Methods

Method Description
getCoolingWaterFlowRate(String) Get CW flow rate (kg/hr, kg/sec, etc.)
getDuty() Get heat duty (W, negative for cooling)
getOutletStream() Get cooled process stream

ReBoiler

Constructors

Constructor Description
ReBoiler(String name, StreamInterface inStream) Create with inlet stream

Configuration Methods

Method Description
setReboilerDuty(double) Set heat input (Watts)

Results Methods

Method Description
getReboilerDuty() Get heat duty (Watts)
getOutletStream() Get heated outlet stream