Project Synopsis

Feasibility study for converting existing natural gas fired furnaces to coal firing.

Project Summary


The client operates a bentonite processing plant.  The client hired Process Engineering Associates, LLC (PROCESS) to conduct a feasibility study for converting the existing natural gas fired furnaces for the two rotary dryers, three Raymond roller mills, and two Williams hammer mills to coal firing.  The bentonite plant processes raw bentonite into a variety of products utilizing natural gas furnaces to provide the heat required for drying and milling operations.

The following project tasks were completed by Process:

  1. Project kickoff meeting / site visit
  2. Process design basis development
  3. Computer process modeling and simulation
  4. Heat source alternatives evaluation
  5. Project review meeting / alternatives selection
  6. Capital and ROR cost estimates preparation
  7. Project report preparation/submission.

PROCESS conducted a site visit to discuss the scope of the study with the client and to obtain process information: drawings, historical data, original equipment design information, and plant layout.  The client expressed interest in pursuing alternative heat sources including stoker furnaces, heating mediums with air heat exchangers, and pulverized coal for all of the heating needs.  Very little process information was available including no drawings, manuals, or historical process data except for a manual for the Williams hammer mills.  Therefore, the initial site visit included PROCESS personnel collecting process data, equipment information, plant layout, and process flow schematics to facilitate modeling of the bentonite dryers and mills.

PROCESS placed all of the gathered information into a design basis document for client agreement to facilitate efficient simulation efforts and provide the basis for the feasibility study.  PROCESS then individually simulated the rotary dryers, the roller mills, and the hammer mills using PROCESS’ licensed computer simulation software and tuned the models to collected plant data.  PROCESS then modeled the three systems at the design basis conditions to establish the heat and material balance (H&MB) and process parameters.

PROCESS utilized the final design basis models to determine the feasibility of the various heat source options available to the client to efficiently choose the best options for further development.  PROCESS then met with the client at the plant site to review the results and determine the options to be progressed.  As part of the review meeting, the client was given the economic rates of return (RORs) for the project to assist the client in determining the capital cost justification.

PROCESS then fine tuned the models based upon the final options selected, the client supplied coal composition, and the furnace type.  PROCESS provided a feasibility study class cost estimate for the project using cost factor estimate tools based upon furnace vendor budget quotes.  PROCESS then provided the client with the economic returns based upon the benefit analysis and the cost estimate for the option selected.

The information resulting from this project was summarized in a project report submitted to the client.

Industry Type

  • Minerals Processing

Utilized Skills

  • Computer process modeling and simulation
  • Heat source alternatives evaluation
  • Alternatives selection
  • Capital and ROR cost estimates preparation
  • Front end engineering design study

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