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:

• Friedrich, Ferrari and Brandani: Efficient simulation and acceleration of convergence for a Dual Piston Pressure Swing Adsorption (DP-PSA) system. Ind. Eng. Chem. Res., 2013, 52 (26), pp 8897–8905.
• Banu, Friedrich, Brandani, Düren: A Multiscale Study of MOFs as Adsorbents in H₂ PSA Purification. Industrial & Engineering Chemistry Research, 2013.
• Wang, Friedrich, Brandani: Characterisation of an automated Dual Piston Pressure Swing Adsorption (DP-PSA) system. Energy Procedia, in press.