Control of Temperature and Aluminum Fluoride Concentration Based on Model Prediction in Aluminum Electrolysis

The temperature and the aluminum fluoride (AlF3) concentration of electrolyte greatly affect the current efficiency and energy consumption in aluminum electrolysis. This paper developed a new kind of algorithm to control the temperature and AlF3concentration of electrolyte for 300 kA prebake aluminum production cells by altering the setting cell voltage and the AlF3adding rate. One is liquidus model which can be used to calculate AlF3concentration of electrolyte by some technical parameters and target superheat and the other is the temperature models which can determine the required cell voltage by the technical parameters and target temperature. Consequently, the AlF3addition rate can be decided by the AlF3concentration. The temperature and AlF3concentration of electrolyte in the production are measured and the differences between the measurement and the corresponding calculation are used as feedback to correct the model. The coefficients in the model are also revised according to the external conditions. This system has been used in an aluminum company for 2 years. Both the temperature and the AlF3concentration of electrolyte can be controlled as required and the energy consumption of the aluminum production was much decreased.

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Metal Instabilities and its Effect on Cell Performance during Aluminium Smelting

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.828.45 ◽

2013 ◽

Vol 828 ◽

pp. 45-54 ◽

Cited By ~ 1

Author(s):

Anupam Agnihotri ◽

Shail Umakant Pathak ◽

Jyoti Mukhopadhyay

Keyword(s):

Energy Consumption ◽

Current Efficiency ◽

Cell Voltage ◽

Aluminum Electrolysis ◽

Cell Performance ◽

Consumption Pattern ◽

Magnetic Current ◽

Zero Current ◽

Aluminium Smelting ◽

Rolling Noise

The Hall-Heroult process for the production of aluminium is based on the electrochemical reduction of alumina (Al2O3) dissolved in a cryolite (Na3AlF6) based electrolyte. Instability in cell voltage is referred to as noise. Normal voltage noise is inevitable due to bubble evolution and it has little effect on performance parameters such as, current efficiency and power consumption. Metal rolling noise (wavy noise) is caused by the disturbances in cell magnetic field and it affects the cell current efficiency adversely. Investigating the causes of the cell instability in the aluminium smelting cells can lead to better cell performance. Understanding the variation in cell voltage is critical for cells, because magnitude of voltage determines the energy consumption pattern in the process and hence, any saving on voltage can save energy. Voltage affects the current efficiency of the cell and an optimum cell voltage leads to higher current efficiency without compromising on energy consumption. Magnetic, current distribution, heat loss and voltage at zero current measurements along with online current and voltage signal can help to identify the problems and their combined effects on the performance of the cells. In order to estimate the loss in current efficiency of the aluminum electrolysis cells due to metal instabilities, measurements were performed and data analyzed. The present paper analyses the effect of voltage fluctuations (noise) during metal instability along with cause of instability and its effect on current efficiency of the cell. Measurements carried out to estimate the deviations from the normal cell operations are also discussed.

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A ALO-LSSVM Model for the Cell Voltage Optimization in Aluminum Electrolysis Process

2020 39th Chinese Control Conference (CCC) ◽

10.23919/ccc50068.2020.9189558 ◽

2020 ◽

Author(s):

Chen-hua Xu ◽

Jin-zhi Zhang ◽

Ruo-jun Cheng ◽

Rui Chen ◽

Zhu-guang Luo ◽

...

Keyword(s):

Cell Voltage ◽

Aluminum Electrolysis ◽

Electrolysis Process

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THERMAL CAPACITY OF ENRICHED FUEL BRIQUETS PRODUCED FROM THE FINE OF EKIBASTUS COAL

International Journal of Engineering Technologies and Management Research ◽

10.29121/ijetmr.v4.i9.2017.99 ◽

2020 ◽

Vol 4 (9) ◽

pp. 49-64

Author(s):

Ye.S. Abdrakhmanov ◽

A.V. Bogomolov ◽

P.O. Bykov ◽

A.B. Kuandikov

Keyword(s):

Research Work ◽

Calorific Value ◽

Aluminum Electrolysis ◽

Thermal Capacity ◽

Machine Building ◽

Aluminum Production ◽

Petroleum Pitch ◽

Scientific Publications ◽

Laboratory Equipment ◽

Or Methodology

The object of research or development: The object of the research work was coal fines and processes of enrichment of Ekibastuz coal to produce fuel briquettes with increased calorific value and less ash content. Objective: Research, scientific substantiation of technology for obtaining high-calorific coal briquettes from fines of Ekibastuz coal using various binders and the possibility of further coking, designing and manufacturing equipment for the implementation of technology. Method or methodology of the work: The standard methods of theoretical and experimental research widely used in metallurgy, machine building, computer systems, etc. were used in the work. The results of the work and their novelty: The characteristics of briquettes on bio-binding and on petroleum pitch with enrichers in the form of rubber-technical soot and anode dust of electrolysers for aluminum production have been established. It is revealed that the calorific value of briquettes is higher than that of Ekibastuz coal(Pavlodar region) by 20-40%, and the heating value is the highest for briquettes with an enrichment agent in the form of anode dust and a binder in the form of petroleum pitch (-NH combustion = 6840.8 kcal / kg). The structures of the soot separator, sorting and sifting equipment, mixing laboratory equipment, the mouthend briquetting press, the briquetting press and the screw mixer with the heater have been designed. Based on the results of the research, the project manager and co-authors published 15 scientific publications, patents and theses of international conferences. Application area: Briquettes for bio-binding can be used as fuel for combustion in centralized village boiler houses, private houses and farms. Briquettes on petroleum pitch with an enrichment agent in the form of anodic dust of aluminum electrolysis can be used as industrial briquettes for further use in metallurgy. Forecasting assumptions about the development of the object of research: Further studies are required to assess the feasibility of using industrial briquettes for coking and use in metallurgy, the manufacture of laboratory and research equipment to further commercialize the project.

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Electrorefining of aluminum alloy in ionic liquids at low temperatures

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb0302043k ◽

2003 ◽

Vol 39 (1-2) ◽

pp. 43-58 ◽

Cited By ~ 19

Author(s):

V. Kamavaram ◽

D. Mantha ◽

R.G. Reddy

Keyword(s):

Aluminum Alloy ◽

Ionic Liquids ◽

Energy Consumption ◽

Low Temperatures ◽

Cell Voltage ◽

Liquid Electrolyte ◽

X Ray ◽

Ionic Liquid Electrolyte ◽

Anhydrous Alcl3 ◽

Xrd Techniques

The electrorefining of aluminum alloy (A360) in ionic liquids at low temperatures has been investigated. The ionic liquid electrolyte was prepared by mixing anhydrous AlCl3 and 1-Butyl-3- methylimidazolium chloride (BMIC) in appropriate proportions. The effect of the cell voltage temperature, and the composition of the electrolyte on the electrorefining process has been studied. The characterization of the deposited aluminum was performed using scanning electron microscopy (SEM) and X-ray diffraction (XRD) techniques. The influence of experimental parameters such as cell voltage and concentration of AlCl3 in the electrolyte on the deposit morphology was discussed. The composition of the aluminum deposits was analyzed using X-ray fluorescence spectrometer (XRF). Aluminum deposits with purity higher than 99.89 % were obtained. At a cell voltage of 1.0 V vs. Al/Al(III), the energy consumption was about 3 kWh/kg-Al. The main advantage of the process is low energy consumption compared to the existing industrial aluminum refining process.

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Study of the energy consumption of the piped vehicle hydraulic transportation

Advances in Mechanical Engineering ◽

10.1177/1687814019885541 ◽

2019 ◽

Vol 11 (11) ◽

pp. 168781401988554 ◽

Cited By ~ 3

Author(s):

Yongye Li ◽

Xihuan Sun ◽

Xuelan Zhang

Keyword(s):

Energy Consumption ◽

Total Energy ◽

Reynolds Numbers ◽

Length Ratio ◽

Hydrodynamic Theory ◽

Calculation Formula ◽

Straight Pipe ◽

Total Energy Consumption ◽

Bend Pipe ◽

Technical Parameters

The piped vehicle hydraulic transportation is a new energy-saving and environmental-friendly technique for transporting materials. To optimize the technical parameters of the piped vehicle hydraulic transportation, the transporting energy consumption of the technique was studied by a combination of theoretical analysis and experiments. Experiments were conducted at six piped vehicles with the diameter–length ratios of 0.4, 0.6, 0.47, 0.7, 0.53, and 0.8, seven flow Reynolds numbers of 102,140, 132,413, 167,014, 200,534, 234,037, 267,556, and 299,993, two transporting loads of 1200 and 1500 g, and three pipe layout forms of straight pipe, flat bend pipe, and inclined bend pipe. The results showed that the total energy consumption of the piped vehicle hydraulic transportation increased with increasing flow Reynolds numbers and increasing mass of transporting materials. The total transporting energy consumption of a piped vehicle with the diameter–length ratio of 0.53 was the highest, and that of a piped vehicle with the diameter–length ratio of 0.47 was the lowest. The unit transporting energy consumption of a bend pipe was higher than that of a straight pipe. Meanwhile, the total energy consumption of the piped vehicle hydraulic transportation was analyzed by hydrodynamic theory. The calculation formula for the total energy consumption of the piped vehicle hydraulic transportation was obtained and validated experimentally. The maximum relative error did not exceed 8.07%, proving that the total energy consumption calculation formula of the piped vehicle hydraulic transportation was rational. By analyzing the transporting efficiency of piped vehicle hydraulic transportation under different influencing factors, the optimal transporting combination was the piped vehicle with the diameter–length ratio of z = 0.47 and the flow Reynolds number of Re = 200,534. The results of this study can provide a theoretical basis for optimizing the technical parameters of the piped vehicle hydraulic transportation.

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Study on movable light-shelf system with location-awareness technology for lighting energy saving

Indoor and Built Environment ◽

10.1177/1420326x16659691 ◽

2016 ◽

Vol 26 (6) ◽

pp. 796-812 ◽

Cited By ~ 7

Author(s):

Heangwoo Lee ◽

Sang-hoon Gim ◽

Janghoo Seo ◽

Yongseong Kim

Keyword(s):

Energy Consumption ◽

Energy Saving ◽

Energy Savings ◽

Full Scale ◽

Location Awareness ◽

Energy Saving Potential ◽

Recent Increase ◽

Lighting Energy ◽

External Conditions ◽

Incoming Light

Various ongoing studies regard light-shelves as one solution to the recent increase in lighting energy consumption. However, in previous light-shelf systems, the direction of incoming light was determined by external conditions, thereby limiting the efficiency of lighting energy saving. The purpose of the present study was to develop a movable light-shelf system with location-awareness technology and verify its performance. In this study, a full-scale testbed was established in order to test the proposed movable light-shelf system with location awareness as well as to verify its energy saving potential. The results were analysed and compared with the performances of previous fixed (Case 1) and movable (Case 2) light-shelf systems without location-awareness technology. The obtained results were as follows. (1) The proposed light-shelf system can respond to external conditions and to the location of the occupant by means of the control axis of the light-shelf module angle through modulation between the control axis of the angle of the previous light-shelf and the reflector of the light-shelf. (2) The proposed light-shelf system provides 90.0% and 86.6%/91.0% energy savings in comparison to Case 1 and Case 2, respectively.

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Liquidus temperatures of Na3AlF6-AlF3-CaF2-KF-LiF-Al2O3 melts

Journal of Mining and Metallurgy Section B Metallurgy ◽

10.2298/jmmb130606040p ◽

2014 ◽

Vol 50 (1) ◽

pp. 23-26 ◽

Cited By ~ 2

Author(s):

J.P. Peng ◽

Y.Z. Di ◽

Y.W. Wang ◽

Y.B. Bai ◽

N.X. Feng

Keyword(s):

Thermal Analysis ◽

Mass Fraction ◽

Empirical Equation ◽

Aluminum Electrolysis ◽

Primary Crystallization ◽

Molar Ratio ◽

Aluminum Fluoride ◽

Electrolyte System ◽

Electrolysis Process ◽

Liquidus Temperatures

Temperatures for the primary crystallization of Na3AlF6-AlF3-CaF2-KF-LiF-Al2O3 system adopted in aluminum electrolysis process were determined by thermal analysis. An empirical equation was derived to describe the liquidus temperatures for the primary crystallization of this multicomponent electrolyte system: t/?=1011 + 0.7w(AlF3) - 0.232w(AlF3)2 - 7.65w(Al2O3) + 0.523w(Al2O3)2 - 8.96w(LiF) + 0.043w(LiF)2 - 3.32w(KF) - 0.12w(KF)2 - 3.28w(CaF2) +0.037w(CaF2)2 + 0.091w(AlF3)w(LiF) + 0.074w(AlF3)w(KF) + 0.084w(AlF3)w(CaF2) - 0.27w(Al2O3)w(LiF), where w(AlF3) denotes the mass fraction of excess aluminum fluoride with respect to cryolite. While w(Al2O3) ranges from 2% to 4%, w(LiF), w(KF) and w(CaF2) from 0 to 7%, and the molar ratio of NaF/AlF3 from 2.2 to 3.

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Design features of thermal furnace with a drum mechanism for blanks transportation

Izvestiya Ferrous Metallurgy ◽

10.17073/0368-0797-2021-2-89-94 ◽

2021 ◽

Vol 64 (2) ◽

pp. 89-94

Author(s):

N. A. Cheremiskina ◽

N. V. Shchukina ◽

N. B. Loshkarev ◽

V. V. Lavrov

Keyword(s):

Energy Efficiency ◽

Energy Consumption ◽

Specific Energy Consumption ◽

Developed Countries ◽

High Energy ◽

Flow Diagram ◽

Heating Process ◽

Specific Process ◽

Technical Parameters ◽

Improve Energy Efficiency

One of the most energy-intensive industries is ferrous metallurgy. The metallurgical sector in industrially developed countries is reducing its specific energy consumption per one ton of products by approximately 1.0 – 1.5 % per annum. In Russia, obsolete technology is the main reason for the high-energy intensity of industrial product. Energy saving in industrial production is associated with production technology and the scope of fuel and energy resources consumption. Therefore, ways to improve energy efficiency focus on reducing energy consumption of any kind during a specific process in a specific process or thermal unit. Ensuring the economical operation of furnace units requires detailed preliminary and verification analyses, upgrading and introduction of state-of-the-art equipment. The study presents a flow diagram and features of thermal operation of a new drum-type chamber furnace for heating metal products for quenching. The technical parameters of the furnace, the results of the thermo-technical analysis, the heat balance and the specific fuel consumption as applicable to the created design are also presented. The flow diagram of the furnace has significant advantages in terms of the energy efficiency of fuel as compared to the roller and conveyor methods of metal transportation. Placing blanks on the drum significantly reduces the complexity of their transportation. Thanks to its small length the proposed design is compact and easy to place in a workshop. The use of a recuperative fuel burning device allows the efficient use of the heat of waste gases in the heating process. The proposed design and method of products transportation in the furnace working space can be used for the heat treatment of bars, pipes, strips, as well as rolled steel of various shapes.

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