Improved Heat Treatment Process Control For Fuel Efficiency And Cycle Time Reduction
Open Access
- Author:
- Karnezos, Thomas C.P.
- Graduate Program:
- Industrial Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- None
- Committee Members:
- Robert Carl Voigt, Thesis Advisor/Co-Advisor
Robert Carl Voigt, Thesis Advisor/Co-Advisor - Keywords:
- heat transfer modeling
heat treatment
process control
fuel efficiency
infrared sensor
gas flow - Abstract:
- This thesis describes the development of an advanced heat treatment process control strategy for natural gas fired furnaces at Carpenter Technology, Corp. in Reading, PA. The primary goal of the project was to implement an improved annealing heat treatment ‘on-heat’ detection method capable of quantitatively determining when a load of metal within a furnace reaches its target temperature. Current practice techniques are subjective and inherently induce overly conservative heat treatment cycles. By more quantitative control of heat treatment cycles, the point in time when the load uniformly reached its target temperature could be determined with increased precision. This precision could facilitate shorter, less conservative heat treatment cycles with process time savings and energy savings. Three different approaches for achieving quantitative on-heat determinism were surveyed including: heat transfer modeling, analysis of furnace gas consumption, and analysis of load surface temperature using an infrared sensor (OP-AID method). By comparison of these different approaches, the best control strategy capable of significant reductions in heat treatment cycle times was found to be the OP-AID method. Although the control strategy based on furnace gas consumption proved to be effective, its responsiveness was degraded by the amount of signal filtering it required. Also, since the OP-AID method reacted directly to the surface temperature of the load, it could better ensure product quality compared to the gas flow rate analysis that reacted indirectly to the furnace environment temperature. Additionally, an analysis was conducted to study the balance between metallurgical constraints vs. cost constraints in the design of the OP-AID method. The aggressiveness associated with achieving time savings opposed the maximization of metallurgical specifications (load temperature uniformity), and this balance was quantified through a multi-criteria analysis. Through this analysis it was found that the parameters of the OP-AID method could provide heat treatment cost savings with sufficient product quality.