Ammonia Project 137

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Navigation: User Guide -> Example Projects -> Demonstration Project Descriptions

Ammonia Project

This section is for SysCAD build 137 or earlier. For the project description in the latest version, please see Demo Ammonia Project

Example Projects - Ammonia Example.png

Project Location

This is a Steady State project and is stored at:
..\SysCADXXX\Examples\15 Ammonia\Demo Ammonia Project.spf

Features Demonstrated

  1. Shows the use of Compressor
  2. Shows how to flash/condense NH3 using VLE
  3. Shows the use of Simple Heaters
  4. Shows the use of Shell and Tube Heat Exchanger in Fully Evaporating Mode.
  5. Shows the use of Simple Condenser
  6. Shows the use of Simple Heat Exchanger

Brief Project Description

This is a very simplified ammonia plant. It is used to demonstrate how to simulate complex unit operation by using multiple simple unit operations.

For example:

  1. The reformer is simulated using two Ties unit operations with sub models to handle reactions on both sides as well as heat transfer.
  2. The Evaporator - Flash Vessel - Catch_Pot operations demonstrate how to flashing/condensing NH3 using VLE. The use of VLE will ensure the partial pressures are correct within the unit operation. (This is much more preferable than using a reaction block with forced extents.)
  3. Many other unit operations are simulated using Tie/Tank with reaction sub model for component change
  4. various other heat exchangers are simulated using simple heaters for heat gain/loss.

Project Configuration

SysCAD 9.3 Build 137 and Earlier

Setting up VLE data for components other than water
  • One focus of this example is to show user how to add in flashing/condensing data for their project, to do so, user must first set up the Vapour & Liquid Data in the Species Database:
    1. Edit the SysCAD.93.db3 file to contain the component requiring flashing/condensing.
    2. Make sure the component exist in both (l) and (g) form.
    3. Make sure the Vapour Properties are fully specified for the Gas component, that is, the Vapour Pressure and Critical data are defined. (As per NH3(g) entry in the example project.)
    4. In the project, user can switch on the VLE sub model where flashing is required, change the Component to the required component. (In this example, NH3. See Evaporator, Flash_Vessel or Catch_Pot in the project.)
    5. SysCAD will calculate the VLE based on the pressure in the vessel.
Setting up Shell and Tube Heat exchanges in Fully Evaporating Mode
  • Another focus of this example is to show user how to set up Heat Exchanger in Fully Evaporating mode
    1. Evaporation will occur in the Shell Side only, make sure the stream requiring evaporation is connected corrected. (Project examples are Boiler and Evaporator)
    2. Set RqdOpMode to Fully Evaporating
    3. Define Area, HTC and ApproachDT
Setting up Simple Heat Exchanger
  • The Simple Heat Exchanger Model works out the flow conditions (for one side) based on the user defined dT information. See Ammonia_Cooler in the project.
  • SimpleHX Tab
    1. Define the required Ammonia outlet temperature
    2. Select Other.CalcFlow On
  • Calc Tab
    1. DemandConnection set to General Demand, this will allow SysCAD to work out and set the cooling water flowrate. (The Cooling_Water Feeder must be placed into Demand mode for this to work.)
    2. Define the required Cooling Water temperature
Cooling Water Supply Feeder
  • The Cooling_Water Feeder in this project will provide water demanded by Ammonia Cooler.
    1. FeederSink (or Feed_XPG-1) Tab, Select Demand.On, check that Demand.Max will cover the flowrate range for the project. Increase this value if necessary.
    2. Qm_Rqd will represent the minimum value for the steam supply. If this value is higher than downstream requirements, the excess amount is distributed. Recommend using a small number of this field.
    3. Define the operating condition and composition.
    4. SysCAD will calculate the feed flowrate and display it in the Results:Flow Conditions Qm field.

Included Excel Report

  1. Example Plant Criteria Report, used to set data into SysCAD as well as reporting back the actual values from SysCAD.
  2. Example Reactions Report detailing all the reaction and reaction extents used in the project.
  3. Example Stream Report