Evaluate/troubleshoot and subsequently re-design the back end of a used tire pyrolysis plant for the production of commercial value oil products.
TIRE PYROLYSIS PLANT TROUBLESHOOTING AND PROCESS DESIGN PACKAGE PREPARATION
The client, an independent process developer and plant operator, had constructed a commercial scale plant to process several tons/day of waste tires for the recovery of steel and production of salable oils. The overhead vapors from the pyrolysis retort furnace were to be condensed and processed to produce the oils but this portion of the process, the client’s original design, was not working properly. Process Engineering Associates, LLC (PROCESS) was initially contracted to evaluate/troubleshoot this portion of the process.
After reviewing the current process documentation, operating data, and the literature associated with tire pyrolysis plant, PROCESS forwarded recommendations that led to the requirement that the entire portion of the process downstream of the retort furnace be redesigned. The client agreed and further commissioned PROCESS to help define a viable conceptual process and prepare a preliminary heat and material balance and preliminary process design information. The preliminary design information developed at this point included:
- Conceptual block flow diagrams (BFDs) and matching process description
- Process alternatives evaluation that included a search for information in the public domain, patents, and research literature to identify and evaluate alternate technologies that may be capable of producing both salable oils from the pyrolized tire vapors as well as produce activated carbon from the char left in the bottom of the retort furnace
- Preliminary list of, and designs for the major process equipment items required (condensers, heat exchangers, pumps, flare / thermal oxidizer, etc.)
- Order of magnitude cost estimate for selected major equipment items that could be determined from the initial modeling.
PROCESS provided a report to the client conveying the findings of the study. It was determined to that engineering efforts should focus on the design for the production of reclaimed oils.
PROCESS was then contracted to prepare a detailed process design package for a proposed process that would include tire feed to a current and future number of batch retorts, with the pyrolysis gas from the retorts fed to an appropriate number of oil condensing systems, to include the normal and emergency flare/thermal oxidation system for the non-condensable off-gas.
Specific tasks included:
- Generation of a design basis that included the desired production range, operating schedule, space constraints, and scalability of the process.
- Preparation of a heat and material balance for the system using PROCESS' licensed commercial simulation software, CHEMCAD. Unit operations included the retort system, impingement condensers, and associated heating and cooling loops which included the use of both shell and tube heat exchangers as well as fin-fan air cooler units.
- Preparation of process flow diagrams (PFDs) using the heat and material balance data. Since this was a semi-batch operation, PFDs were prepared to define both batch operating conditions and maximum (design) transfer rate conditions.
- Preparation of piping and instrumentation diagrams (P&IDs) for the process. These P&IDS included all major equipment items, process and utility streams, and primary instruments and controls. A detailed Process Description was generated to explain the process flow through the equipment. A Process Control Description was also prepared to describe the functionality of all the process controls.
- Preparation of equipment, valve, and instrument lists for the process. Data sheets were generated for all major pieces of equipment.
The client is in the process of constructing the tire pyrolysis and associated oil condensation plant at its facility in the Western U.S. PROCESS continues to be their process engineering consultant and is currently involved in assisting the client with the evaluation and procurement of used equipment for the plant.
- Waste Recycling
- Process troubleshooting
- Process design
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