Reduction of Energy Consumption in Investment Casting Process by application of a New Casting Facility Mark Jolly, Xiaojun Dai, Binxu Zeng Presenter: Xiaojun Dai 25-26 th October 2011 School of Mechanical Engineering University of Birmingham Sustainable Thermal Energy Management in the Process Industries SusTEM2011, Newcastle, 25th-26th October 2011
Project Summary Project sponsored by EPSRC & implemented by university of Birmingham; Aims: Use new casting method to reduce energy consumption and improve product quality; A new casting method - CRIMSON; Investment casting process (ICP); Comparison between new casting method and current ICP. Investigation and assessment on energy consumption;
CRIMSON Method Invented by university of Birmingham and N-Tec Co. Ltd. Employs a high-powered furnace to melt just enough metal to fill a single mould in a closed crucible; The crucible is transferred to a station for computercontrolled counter gravity filling of the mould/shell for optimum filling and solidification; Holds the liquid aluminium for a minimum of time drastically reducing the energy losses; Other features: rapid melting times achieved, up casting, no turbulence during filling, few hydrogen absorbed, few oxide films formed, improve the quality.
Layout of the CRIMSON Facility
Induction Furnace and Crucible
Current Investment Casting Process Flow chart of a typical Investment Casting Process (ICP) in a foundry
Current Investment Casting Process A typical Crucible Furnace used in Investment Casting Process (ICP) in a foundry
Comparison between new casting method and current ICP Current ICP melting process: Gas for heating and crucible furnace for container; The CRIMSON melting process: use induction furnace and electricity for heating; Current ICP: Gravity casting method top filling; The CRIMSON method: counter-gravity casting method bottom filling;
Energy Balance in Crucible Furnace Schematic of energy balance in the crucible furnace of Aeromet Co Ltd.
Energy Balance in Induction Furnace Schematic of energy balance in the induction furnace of the new process.
Assumptions on the Experiments and Analysis Based on the calculation simplicity, both aluminium ingots used in crucible furnace and induction furnace are assumed as pure aluminium; The system is considered as continuous steady state which includes fuel flow, air flow rate, melting rate, flue gas parameters and thermal conduction through furnace wall; The fuel and combustion products behave as ideal gas mixtures; The environment temperature and pressure are taken as standard 25ºC and 1 atm correspondingly, which are also applied to gas, combustion air and aluminium ingot; The electric energy consumption is only applied to the part of induction heating in induction furnaces, not applied to the motors and control devices which are neglected for the convenient calculation and simplicity; The natural gas composition is considered as pure propane due to the small amount of N 2, CO 2, H 2 S and H 2 O included; The lost metal during drossing is neglected for the calculation simplicity.
Assessment on Energy Consumption Crucible Furnace in Aeromet Energy consumption: the measurements were made to the current melting process (gas) of Aeromet and the new CRIMSON process(electricity); Comparison of the amount and thermal efficiency of energy consumption between the two melting processes;
Assessment on Energy Consumption Data and Table of the energy consumption and thermal efficiency; Melting process Energy consumption Energy efficiency Normal energy efficiency of furnace Aeromet (Gas) 8.65 MJ.kg -1 Gas: 13.86% Gas: 7~19% CRIMSON Induction furnace (Ele) 1.15 MJ.kg -1 Ele: 57.82% 28.91% (50% conversion efficiency from gas to electricity) Ele: 59~76%
Yields of the Two Processes Comparison of yields between the two processes and energy saving using CRIMSON methods Melting process Yield Weight of runner system with four parts Energy saving Aeromet 7.5 % 5.95 kg ---------- CRIMSON 54.5 % 43.2 kg 27.61 MWh.tonne -1 (Producing one tonne of castings)
Conclusions and Future Work To use the novel CRIMSON method instead of the current crucible furnace in conventional ICP foundry, the estimated energy savings could be of the order of 4.69 GJ.tonne- 1 (1.30 MWh.tonne -1 ) for A356 alloy. The estimated production cost could be reduced by 98.80 pounds. tonne -1 (7.6 p.kwh -1 ); If consider the yield, the new method could save 27.61 MWh in producing one tonne of the A356 samples. The estimated production cost could be reduced by 2098 pounds in producing one tonne of the A356 samples; The energy consumption and energy efficiency for other stages of the ICP will be further investigated in this research project.
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