Project Synopsis

Provide process engineering support to a process equipment design/fabrication firm by developing a detailed process design (FEL-3 level) package for a Pressure Swing Adsorption (PSA) Unit in a Cumene production process.

Project Summary


Process Engineering Associates, LLC (PROCESS), was contacted by the client, a designer and fabricator of fluid purification systems, to assist in developing an FEL-3 Level Detail Process Design of a Pressure Swing Adsorption (PSA) Unit.  The PSA Unit is being utilized to treat propylene-laden regeneration gas from a Thermal Swing Absorber (TSA) Unit in a process producing Cumene.  The primary purpose of the process design work was to prepare the needed process engineering documents such that the client can complete the detailed engineering requirements of the process configuration for a third-party client.  A secondary goal of this effort was to provide the client with as-needed on-going process engineering support throughout the multi-discipline detail engineering effort.

PROCESS' initial effort was to develop a Process Flow Diagram (PFD) and Mass and Energy Balance (M&EB) of the PSA Unit.  As operation of the PSA is inherently transient, several computer models were developed to capture the design points used to size equipment and process piping. The commercial flowsheet simulator CHEMCAD was used to generate thermodynamic models that are the basis for the M&EB.  The results of the M&EB were tabulated and summarized in tabular format for easy reference.

The PFD and M&EB were then used to develop a Piping and Instrumentation Diagrams (P&IDs).  PROCESS worked with the client (and the technology licensor and manufacturer of the PSA media) to develop a feed-forward cascading control loop (as well as other, more basic, control elements) to control the PSA regeneration step that was constrained by limited nitrogen availability.  This required development of transient models (in CHEMCAD and MS Excel) as well as close teamwork to ultimately generate a good working design after multiple less successful attempts.

PROCESS developed on/off valve and instrument data sheets and sized all control valves.  PROCESS' in-house PSV sizing software was used to evaluate failure scenarios and properly size all of the safety relief valves used in the PSA Unit design.

Industry Type

  • Process Equipment Design and Fabrication

Utilized Skills

  • FEL-3 / Schedule A / Basic Engineering Package development
  • Simulation of transient condition processes

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