LNG Heat Exchanger Main Window
The LNG Heat Exchanger simulates the exchange of heat between any number of hot and cold streams. The only required data is the designation of each cell as hot or cold. There must be at least one hot cell and one cold cell in the exchanger.
Usage
Cells may be added to the exchanger but the feed and product streams must be defined on the PFD. If a cell is deleted, its feed and product streams will be disconnected on the PFD.
Cell Information:
Each row in the table represents one cell in the exchanger. You may apply either a duty or an outlet temperature specification to cells in the exchanger but at least one cell must remain unspecified. The products from all unspecified cells leave the exchanger at the same temperature.
Cell Name This may be up to 12 characters.
Hot/Cold You must designate each cell as either hot or cold.
Duty or Temperature You may enter a value for either duty or temperature or you may relate one of them to another flowsheet parameter using the Define system.
Cell Data Push this button to display the Cell Data Window where you define product phases, pressure drops and thermodynamic method for each cell.
Zones Analysis button:
Push this button to display the Zones Analysis Window where you can request zones analysis to be performed. Zones analysis is useful when phase changes occur within the exchanger unit.
Print Options button
Print options are not available unless zones analysis is requested. Push the button to display the Print Options Window where you can request printer plots of composite hot and cold stream temperature, duty, UA and temperature difference.
Default Thermo System
Select the thermodynamic system for the exchanger from the list of systems defined in the Thermodynamic Data Window. Different systems may be selected for individual cells in the Cell Data Window.
How to get to this window
The LNG Heat Exchanger window is accessed by double clicking on the LNG Heat Exchanger icon laid down on the Process Flow Diagram.
Standard Heat Curves option
When the Standard Heat Curves option is selected, three standard heating/cooling curves are generated on shell and tube sides of the heat exchanger. These curves are generated at three isobar points: starting pressure, midpoint pressure, and ending pressure. For each curve, 11 evaluation points are considered. Also, for each curve, the transport and critical properties are calculated.