Chemstations Inc., Houston, TX, USA. See also: http://www.chemstations.com

CC-DCOLUMN 5: Dynamic Distillation Column and Dynamic Flowsheeting

CC-DCOLUMN

Any steady state flowsheet can be converted into a dynamic one. Full environment of the distillation tower can be built by use of Dynamic SCDS Distillation, Control Valves, Controllers, Heat Exchangers, Dynamic Tanks, Pumps and all other unit operations of CHEMCAD, including all steady state unit ops.

Initial state for dynamic simulation can be calculated by steady state simulation, which makes CC-DCOLUMN different from other simulators available in the market. Control Valves, Vessels, Distillation Trays or Packing and other equipment can be sized before performing a dynamic simulation. CC-DCOLUMN supports Tray and Packed Tower Mass Transfer model in addition to Regular VLE (equilibrium stage) distillation model.

• Applications

  • Distillation start up and shutdown
  • Design of real distillation systems including reboiler, condenser, side streams, multiple feeds and side heat exchangers
  • Set-point calculation
  • Controller tune-up
  • Scheduled Reflux Control
  • Cascade control
  • Optimization
  • Operator training

• Distillation features

  • Unlimited number of separation stages and unlimited number of unit operations per flowsheet
  • Up to 200 components
  • Mass transfer model, tray or packed column
  • Variable pressure calculations
  • Variable holdup calculations
  • Initial state for calculation includes continuation of a steady state process and start-up conditions
  • Integrated reflux control model in case when discrete control system calculation is not required
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• Dynamic Vessel design

  • Complete dynamics of a process vessel
  • Isothermal or isobaric operation, or TPVH calculated
  • Regulated by control system, vapor vent or liquid overflow
  • Vessel sizing option
  • Automatic two-phase relief system calculations according to DIERS

• Control System dynamics

  • User specified PID loops
  • Multiple ramp or step changes in setpoint
  • Control of reactor or jacket temperature differential
  • PID Controller model
  • Control Valve model
  • Cascade control

• Auxiliary equipment

  • Any unit operation may be used within the dynamic flowsheet to flexibly model the process, e.g., heat exchanger, mixer, divider, separator, valve, pump, pipe, etc.

• Thermodynamics and Physical Property Data

  See: CHEMCAD

• Calculations

  • Initial conditions can be calculated in steady-state
  • Multiple batch operation steps with stop conditions defined by the user
  • Calculation results plotted in run-time for selected variables
  • Parameters of any unit operation or stream can be recorded in time
  • Parameters of complete process can be recorded at pre-determined timesteps
  • Dynamic simulation can be stopped at any time, the results reviewed, and the simulation can be carried on

• Regression

  See: CHEMCAD