CySim - General Adsorption Cycle Simulator

CySim is a modular adsorption cycle simulator applicable to a wide range of adsorption system configurations. CySim is used to simulate a large range of experimental systems in our labs and is provided to our industrial partners in the Adsorption Research Industrial Consortium (ARIC)

Adsorption systems

  • Multiple adsorption columns
  • Connected by splitters, mixers, blowers, valves, tanks, ...
  • Series of cycle steps: pressurisation, feed, purge, ...

Simulation of adsorption systems

  • Dynamic system with many parameters and variables
  • Non-linear Partial Differential-Algebraic Equations (PDAEs) with hyperbolic character
  • Hyperbolic character leads to shock formation and propagation
  • Different length scales: column, pellet, crystal, ...
  • Different time scales: convection, macro- and micropore diffusion, adsorption, heat transfer, ...
  • Convergence to Cyclic Steady State (CSS) can be slow

Features of CySim

  • Modular system with different units: adsorption columns, valves, mass flow controllers, splitters, tanks, blowers, ...
  • Arbitrary number of gas phase components
  • Each unit has a hierarchy of models for various complexities of the mass, momentum and energy balances:
    • Micropore mass transfer: equilibrium, Linear Driving Force (LDF), pore diffusion
    • Macropore mass transfer: no resistance, Linear Driving Force (LDF), pore diffusion
    • Isotherms: linear single-site Langmuir, dual-site Langmuir
    • Momentum balance: no pressure drop, Ergun equation
    • Energy balance: isothermal, non-isothermal with no resistance between fluid and solid, full non-isothermal
  • Connecting units allow the integration into full plant flowsheet simulations, e.g. Unisim
  • Arbitrary number and connection of units
  • Simulate different cycle configurations by time events, e.g. switching of valves
  • Unibed approach for the simulation of multi-column processes
  • Discretisation schemes are tailored to the characteristics of the problem
    • Flux-limited Finite Volume Method for the gas phase
    • Orthogonal Collocation on Finite Elements Method for the solid phase
  • Accelerate the convergence to CSS
    • Model and discretisation switch
    • Non-sequential cycle calculation: extrapolation algorithm
    • Interpolation of the starting conditions

Related publications:

Pressure profile in the two adsorption columns of the 6 step Skarstrom PSA cycle simulated with CySim.
Pressure profile in the two adsorption columns of the 6 step Skarstrom PSA cycle simulated with CySim.