Project Synopsis

Evaluate multiple technologies, as part of a new antimony refining facility, to regenerate a hydrochloric acid leaching stream from a dilute hydrogen chloride gas stream and to perform a process design of the selected regeneration technology. Simulation Diagram

Project Summary


Process Engineering Associates, LLC (PROCESS) was contracted by the client to perform an alternatives evaluation of technologies for regenerating a hydrochloric acid leaching stream from a dilute hydrogen chloride gas stream and to perform a process design of the selected regeneration technology.  The system is part of an antimony refining facility to be built by the client.

The evaluation, simulation, and design project included the following major tasks:

  • Process design basis development
  • Alternatives identification and technical screening
  • Alternatives technical and economic evaluations
  • Process design and specification of the selected alternative.

The client provided PROCESS with terminal inlet and outlet stream conditions for the regeneration system from which a process design basis was developed.  Technical screening of identified process technologies resulted in the selection of a packed distillation tower and a double-effect evaporator as technologies carried forward for more detailed technical and economic evaluations.  PROCESS then used in-house commercial process simulation software to perform detailed mass and energy balance models of the screened alternatives for the purpose of performing the technical and economic evaluations of the process alternatives.

Based primarily on technical considerations, the packed tower was recommended by PROCESS to be carried forward for process design.  Although the evaporator had an economic advantage relative to energy consumption, the available operating envelope was deemed too small for practical operation relative to meeting the performance requirements for the system as set forth in the process design basis.  The process simulation software was also used during the process design phase of the project for the purpose of determining the total number of required theoretical equilibrium stages, the overall packed height based on the calculated height equivalent to one theoretical plate (HETP), the column reboiler heat duty, and the column optimum diameter.  PROCESS also selected the packing type and materials of construction based on knowledge of, and experience with similar applications.

Subsequent to process design and system specification, PROCESS executed several additional process simulations for the purpose of predicting column performance under various operating conditions.

The simulation tasks for this project were especially challenging due to the non-ideality of the HCl/water system, the complicating presence of antimony trichloride (SbCl3), and the presence of an azeotrope.  PROCESS used experimental vapor pressure data for the HCl/H2O/SbCl3 system and regressed this in the simulator thermodynamics package for the purpose of generating accurate vapor-liquid equilibrium data for the alternatives evaluation and process design tasks

Industry Type

  • Minerals & Metals Refining

Utilized Skills

  • Alternative technologies evaluation
  • Azeotropic distillation
  • Distillation column design
  • Multiple-effect evaporator evaluation
  • VLE data generation
  • Front end engineering design (FEED)

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