(558a) Parametric Sensitivity Analysis for Pressure Swing Adsorption Systems

Zhang, L., Aspen Technology, Inc

The design of pressure swing adsorption is a challenging task because of the simultaneity of transport, adsorption and desorption phenomena (i.e. fluid flow, mass transfer and/or heat conduction) inherent to the processes, which are mathematically modeled by partial differential equations (PDEs) with spatial temporal variations. The high degree of uncertainty in addition to process operational uncertainties (e.g. daily fluctuations, seasonal variations in production levels) and physical property uncertainties adds complexity to this already challenging design problem. In most of studies, the thermodynamic and transport properties always are assumed to ideal relationship for reducing the complexity of the problem and avoiding the numerical challenges. However, those assumptions give a source of model uncertainty and prevent us to operate and design the PSA system reliable and efficiently. In this presentation, with help of Aspen HYSYS automation, a simple and rigorous thermodynamic and transport properties models are compared to minimize this uncertainty. Parametric sensitivity analysis of thermal, kinetic and material properties will be illustrated for this distributed system in two dimensions with full consideration of parameter and model uncertainty.

We will address the PSA systems with the transient transport phenomena i.e. diffusion, convection, equilibrium, thermodynamic equations of distributed systems in the presence of parameter uncertainties. We will assess the distributed system by solving the transport equations with the help of the discretization scheme i.e. finite volume method. First and second order sensitivity information will be provided to address impacts of variation of the thermal, transport and material properties on the PSA system. In particular we will argue for the cyclic steady state condition and product purity concern, ensuring operability and risk management under uncertainty.

In this presentation we highlight how rigorous thermodynamic model and transport equations with the detailed parameters analysis can help design engineers and plant managers to select the PSA with high performance. Simultaneous consideration of design and uncertainty offers higher flexibility and lower expected cost at the operating stage.