Project Synopsis

Develop an FEL-2.5 process design package for a new polyester polyol production facility.

Project Summary

The client, a manufacturer of building construction materials, contracted Process Engineering Associates, LLC (PROCESS) to develop an FEL-2.5 process design for a new polyester polyol production facility.  The work completed in this FEL-2.5 project builds on the efforts of the client’s laboratory and pilot activities and PROCESS’ previously-completed FEL-0/1 process design.

Polyester polyols are one of the components utilized to produce poly-iso foam products used as rigid insulation in commercial building construction.  To address projected increases in demand, the client is looking to produce more polyol for use in their foam insulation production plants.

The primary raw materials are Diethylene Glycol (DEG) and Phthalic Anhydride (PA). DEG is received as a liquid by rail car and transferred to a N2-padded storage tank.  PA can arrive at the plant either as a molten liquid in rail car (preferred) or as a flaked solid material in supersacks.  Molten railcars are steamed on-site to ensure the PA is completely liquid and pumpable.  Flaked PA is unloaded and stored in a warehouse. Flaked material is later melted for use in a reactor.

The plant is designed to produce variations of a single product, polyester polyol.  The heart of the plant consists of multiple trains of batch reactors, which operate on a staggered cycle to smooth out demands on shared utility systems.  The reactors are jacketed (heating and cooling) and agitated.  The reaction is run at high temperature under vacuum.  Vapor off the reactor is routed through a rectification column and partial condenser to remove unwanted water and dioxane (reaction byproducts).  A large recirculation flow of liquid reactor contents is used to efficiently heat/cool the reactor.  A stripping column is used to remove/sparge water vapor from the recirculated liquid.  A liquid ring-based vacuum system is used to control reactor pressure and develop a vacuum that pulls most of the water vapor out of the reaction area.

Heat and material balance (H&MB) tables and Process Flow Diagrams (PFDs) were developed for the plant configuration.  The PFDs were used to generate Piping and Instrumentation Diagrams (P&IDs) for the unit.  The P&ID and H&MB data were used to develop equipment specifications.  The specifications were generated with enough detail such that equipment vendors were able to provide budgetary equipment supply proposals.  All process equipment, valves, and instrumentation were tagged and compiled in tabular format.  This information was used to generate a factored cost estimate for the installed equipment.

Industry Type

Building Construction Materials Manufacturing

Utilized Skills

  • FEL-2.5 process design package development
  • Process scale up design

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