Project Synopsis

Provide an independent engineering evaluation study of ways to reduce plant utility energy consumption for a proposed waste lubricant recycling facility.

Project Summary


Process Engineering Associates, LLC (PROCESS) was contracted by the client, a spent motor oil recycling concern, to review a conceptual process design for a used motor oil re-refining plant proposed for construction in the U.S., and to recommend ways to reduce electrical and natural gas utility usage.  The conceptual process diagrams were developed by an overseas specialty engineering company that has designed several such plants for international locations.  Specific tasks in the energy reduction study included:

  • Review process block-diagrams, preliminary PFDs, and preliminary material balances
  • Determine the largest energy users and producers, both thermal and mechanical
  • Identify conventional process options for matching producers and users to recover energy
  • Identify and evaluate unconventional means of reducing energy, such as thermal and/or electrical conversion of solar energy
  • Write a letter report of findings and recommendations.

PROCESS reviewed the preliminary PFDs for heat integration opportunities and suggested a number of places where product waste heat could be recovered into feed streams.  PROCESS also looked at an incinerator operation and suggested a way whereby waste heat could be captured to help reduce the plant electrical load.  Additionally, PROCESS suggested that mechanical energy could be recovered from two high-pressure liquid streams that would flash (partially vaporize) during depressuring.

For unconventional energy reduction, PROCESS investigated the possibility of placing photovoltaic solar panels on a large product blend facility building roof.  A second option investigated installing conventional or high-efficiency solar collector panels to heat water which could be used to heat cold process fluids. This work involved:

  • Researching the average solar energy available in the geographic area of the proposed plant
  • Considering whether solar electric power could be used for process purposes
  • Estimating the cost for a photovoltaic system that could handle building lighting
  • Evaluating the potential for solar thermal energy utilization via conventional “flat plate collector” panels with serpentine water coils or special “evacuated tube collectors”
  • Doing payout calculations for the solar energy options investigated.

A summary report was written conveying the results of both the conventional and unconventional energy reduction studies.

Industry Type

  • Waste Lubricant Recycling

Utilized Skills

  • Independent third party process evaluation
  • Process energy conservation evaluation

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