Reduction of Carbon Footprint and Energy Efficiency Improvement in Aluminum Production by Use of Novel Wireless Instrumentation Integrated with Mathematical Modeling

James W. Evans

关键词: ALUMINIUM;    ANODES;    CARBON FOOTPRINT;    COMMERCIALIZATION;    COMPUTERS;    DISTRIBUTION;    ECONOMICS;    EFFICIENCY;    ELECTROLYTIC CELLS;    ENERGY CONSUMPTION;    ENERGY EFFICIENCY;    GREENHOUSE EFFECT;    GREENHOUSE GASES;    MONITORING;    OPERATING COST;    ORGANIC FLUORINE COMPOUNDS;    OXIDES;    SMELTERS Aluminum production;    greenhouse gasses;    anode effect;    current efficiency;    aluminum smelting;    wireless sensing.;   

DOI  :  10.2172/1038144
RP-ID  :  DOE/EE0003500
PID  :  OSTI ID: 1038144
Others  :  TRN: US201208%%878

美国|英语

来源: SciTech Connect

【 摘 要 】

The work addressed the greenhouse gas emission and electrical energy consumption of the aluminum industry. The objective was to provide a means for reducing both through the application of wireless instrumentation, coupled to mathematical modeling. Worldwide the aluminum industry consumes more electrical energy than all activities in many major countries (e.g. the UK) and emits more greenhouse gasses (e.g. than France). Most of these excesses are in the 'primary production' of aluminum; that is the conversion of aluminum oxide to metal in large electrolytic cells operating at hundreds of thousands of amps. An industry-specific GHG emission has been the focus of the work. The electrolytic cells periodically, but at irregular intervals, experience an upset condition known as an 'anode effect'. During such anode effects the cells emit fluorinated hydrocarbons (PFCs, which have a high global warming potential) at a rate far greater than in normal operation. Therefore curbing anode effects will reduce GHG emissions. Prior work had indicated that the distribution of electrical current within the cell experiences significant shifts in the minutes before an anode effect. The thrust of the present work was to develop technology that could detect and report this early warning of an anode effect so that the control computer could minimize GHG emissions. A system was developed to achieve this goal and, in collaboration with Alcoa, was tested on two cells at an Alcoa plant in Malaga, Washington. The project has also pointed to the possibility of additional improvements that could result from the work. Notable among these is an improvement in efficiency that could result in an increase in cell output at little extra operating cost. Prospects for commercialization have emerged in the form of purchase orders for further installations. The work has demonstrated that a system for monitoring the current of individual anodes in an aluminum cell is practical. Furthermore the system has been installed twice on a smelter in the US without exposing workers to hazards usually associated with running signal wires in aluminum plants. The results display the early warning of an anode effect that potentially can be used to minimize such anode effects with their excessive GHG emissions. They also point to a possible, but substantial, economic benefit that could result in improved current efficiency by anode adjustment based on individual anode current measurements.