Specific Electrical Consumption Research Articles

Steel Semiproduct Melting Intensification in Electric Arc Furnaces Using Coordinated Control of Electric and Gas Conditions: II. On-Line Control of the State of the Charge and Melt Zones in Electric Arc Furnaces

An algorithm is developed to estimate the rate of charge melting in the electric arc furnace laboratory and its geometric sizes. An electric-arc instability index is proposed as a parameter for on-line control of the heat state of the bath and the rate of metal scrap melting. In practice, a decision about turning off a furnace in melting a charge or about the beginning of the end oxidation stage of a heat is delayed, which leads to an increase in the time of furnace operation under an electric current and in the specific electric power consumption.

Time series analysis of refining conditions and estimated pulp properties in a chemi-thermomechanical pulp process

Frequently sampled process data from a conical disc refiner and infrequently sampled pulp data from a full scale chemi-thermomechanical pulp (CTMP) mill were evaluated to study autocovariance with aspects of potential dynamic modelling applicability. Two trial measurements with an online pulp analyzer at decreased sampling intervals were performed. For variability analysis, time-series containing up to one day of operational data were used. At the chip refiner, the clearest significant autocovariance was identified for the specific electricity consumption, based on the longer sequences. Most of the estimated pulp properties indicated low or non-significant autocovariance, limiting applicability of a specific dynamic model. A mill trial was conducted to investigate the impact from an increase in the conical disc gap on the specific electricity consumption and the resulting freeness. The response time from the gap change in the refiner to measured change in freeness was estimated at 19 min, which was approximately the hydraulic residence time in the latency chest. The relevance of this study lies in applicability of mill-data-driven modelling to capture the dynamics of a specific refining process. Through mill trials the sampling speed of pulp properties was more than doubled to gain insights into short term systematic variations by applying time-series-analysis.

Прогнозирование энергопотребления в период плавки шихты в дуговых сталеплавильных печах

A solution to the problem of selecting the operating arc current at which the minimum amount of electricity is consumed for melting the furnace charge with the specified parameters of the steelmaking electric arc furnace (EAF) equivalent circuit is proposed based on the developed methods of universal and structural characteristics of the arc heat-transfer model (AHTM) is proposed. In solving the problem, the following factors were taken in consideration: the arc heat-transfer conditions in the melting space, the influence of the electrode thermal operation conditions, the influence of arc length on the heat flux structure in heating the charge by arcs, and the effect the chemical composition of working medium has on the thermophysical characteristics of the arc column plasma. The main specific feature of heating by arcs in the EAF melting space is a complex pattern of furnace charge heating due to radiation from arcs and convection as a result of plasma motion in the arc columns. The wide variation range of the ratio of the radiation power to the power transferred by convection has an effect on the furnace charge melting rate and on the amount of electricity consumed in the course of melting. The furnace charge melting intensity depends to a significant extent on the arc radiation power level. The radiation from EAF arcs was numerically analyzed with due regard to the column temperature profile using the arc universal characteristics method by solving the system of nonlinear algebraic equations of the column cylindrical model (ATHM). The arc length is calculated using the ATHM structural characteristics method and consists in comparing the arc voltage calculated from the furnace equivalent circuit equation with the arc voltage calculated using the ATHM. Knowing arc length, it is possible to calculate the arc radiation power in the EAF melting space. After calculating the arc radiation power performance characteristic and the furnace useful power characteristic according to the proposed technique, it is possible to predict the amount of electricity consumed for melting the solid furnace charge and the time of its melting with the furnace being energized. The calculated values of the solid furnace charge melting time for small- and large-capacity EAFs during their energized operation show good agreement with the experimental data. The proposed method for predicting the specific consumption of electricity for melting solid furnace charge in arc furnaces opens the possibility to select — in developing the EAC electric operation mode and in adjusting its operation---the arc operating current at which the maximum solid furnace charge melting rate is achieved and, thereby, to achieve a smaller consumption of electricity in the furnace operating cycle.

Integrated influence of melting parameters of rail steel on rail products quality and technical and economic indicators of the production

Analysis of literature and production data has shown that despite the significant improvement in quality of domestic rail products, achieved in the last decade due to fundamental technical re-equipment of rail production, there is a problem of increased rejection of rails for surface defects. Based on studies of influence of rail steel chemical composition on quality of rails produced by «EVRAZ ZSMK», there was established a significant effect of increasing copper content in the range of 0.07 - 0.15 % and of sulfur - in the range of 0.006 - 0.011 % in E76KhF steel to increase rejection caused by rail surface defects. Mechanism of the influence of these elements concentration in rail steel on finished rails quality was revealed. Decisive influence of ratio of pig iron and scrap in metal charge on copper and sulfur content in rail steel was evidenced - higher rate of cast iron in metal charge within 20 - 50 % contributes to decrease of copper concentration and increase of sulfur content. To justify optimal composition of the charge for rail steel melting in regard to rail products quality and technical and economic indicators of production, study of the effect of cast iron (liquid and solid) to scrap ratio in metal charge on basic parameters of furnaces’ operation was conducted. As a result, it was found that with an increase in share of both liquid and solid iron in metal charge, there are linear decrease in specific electricity consumption, increase in specific oxygen consumption according to parabolic law and a linear decrease in manganese content in furnace output. The obtained dependences of melting duration on ratio of charge components in metal charge indicates presence of prominent minimum, when using liquid iron in the range of 35 - 40 %, and when using solid iron - in the range of 30 - 35 %. Based on the regression equations, statistical model was constructed for the influence of metal charge composition on technical and economic performance of the melt charge in rail steel smelting, in which optimization parameters are: total cost, depending on the metal stock composition and performance of the shop for suitable billets produced by continuous casting. Application of the obtained model allows to develop reasonable recommendations on the optimal proportion of iron in the metal for current level of prices for materials and energy used in electric smelting, taking into account changes in the shop productivity.

ENERGY EFFICIENCY OF OPERATING MODES OF MAIN OIL PIPELINES WITH PERIODICAL PARTIAL OIL DUMPING

Modern oil transportation systems are characterized by a complex hydraulic structure and geometric configuration, and often require the need for a permanent or periodic pumping or dumping part of the oil flow. The implementation of such transportation technology necessarily leads to changes in the operating conditions of oil pipelines and in accordance with the need to regulate the operation of oil pumping stations. Consequently, determining the patterns of the impact of the process of dumping the part of the oil on the energy parameters of the operation of oil transportation systems is an extremely important task.The influence of periodic dumping the part of oil on the energy efficiency of the operation of main oil pipelines was studied. The impact of volume of discharges on the consumption of power on pumping oil in the system of the main oil pipeline was analyzed. It has been found that with the increase the volume of discharges, the specific consumption of electricity for oil pumping decreases.Based on the carried research, the recommendations on the selection of reliable, safe and optimal pumping modes in terms of cost of electricity for the operation of oil pipelines "Druzhba" in the direction of Mozyr - Brody - Tukholsky pass with periodical partial oil dumping on LPDS "Brody".

Carbon emission reduction potential of urban rail transit in China based on electricity consumption structure

With the rapid development of rail transit, a vast amount of electric power is consumed each year. However, the generation of electricity, and especially coal power generation, is an important source of greenhouse gases. Therefore, it is very important to analyze the potential of carbon emission reduction of urban rail transit based on specific electricity consumption structures. In this study, 18 cities in China were taken as the research object, and backward analysis was used to analyze the proportion limit of coal power consumption for rail transit in each city under three scenarios from 2015 to 2017. By comparing the limit value with the actual coal power consumed by urban rail transit, we analyzed the potential carbon emission reduction of rail transit relative to other traffic modes. The study results supported several conclusions. First, the traffic demand is in direct proportion to the carbon emission reduction potential in rail transit. Second, for cities with high coal power consumption, the development of ground bus transit is more conducive to achieving carbon reduction targets compared with rail transit. Finally, promoting the development of rail transit technology and lowering the energy consumption per capita unit travel distance are the fundamental ways to increase the emission reduction potential of rail transit. Therefore, as a modern transportation tool, rail transit is not an absolute emission reduction advantage for all cities. A city needs to analyze its own resource structure and travel demand together, set up suitable traffic modes to realize green growth and sustainable development.

Accounting of energy consumption of passenger electric locomotives in locomotive operational depots

Energy efficiency of transportation process is constantly in the center of attention of specialists and managers of Russian Railways. Some of the new electric locomotives purchased under the investment project have shown unsatisfactory results on electric power consumption. According to the management of the JSC “Russian Railways”, electric locomotives EP20, designed for two types of current, have the highest specific energy consumption. These are modern electric locomotives with powerful asynchronous traction motors. Electric locomotives typically operate in passenger traffic. The purpose of the research was to analyze the accounting of energy consumption of passenger electric locomotives in the locomotive operating depots. The article provides results of a comparative statistical analysis of primary materials on the energy consumption of passenger electric locomotives EP20 and other series of electric locomotives such as EP2K DC and EP1M AC. According to the primary materials from the locomotive operational depots, it was found that passenger electric locomotives with trains of double-decker passenger cars have the highest specific energy consumption. Comparison of specific electric power consumption by electric locomotives with single-type passenger cars showed that with DC electric traction, the consumption level of the EP20 significantly exceeds the consumption of the electric locomotives EP2K; with an AC electric traction, the flow rate of the EP20 is almost equal to the specific electric power consumption of the EP1M electric locomotives. A comparative analysis of the load of EP20 electric locomotives during the maintenance of passenger trains allocated for it in the Moscow — Adler section showed that the electric locomotive was underloaded, which causes a decrease in its efficiency and, as a result, over-consumption of electricity. The use of high-power brake resistors will lead to energy consumption, which must be taken into account in the life cycle cost of EP20 electric locomotives.

ANALYSIS OF ELEC SIS OF ELECTRICITY CONSUMPTION RA Y CONSUMPTION RATIONING A TIONING AT ENTERPRISES FERROUS METALLURGY

Electricity consumption regulation is the primary technical basis for energy consumption planning. Electricity consumption is regulated in the form of specific electricity consumption per unit of production or per unit of work performed. Specific energy consumption rate is understood as the consumption of electricity necessary and sufficient to produce a unit of production or to perform a unit of work in the planned conditions of production and operation. Electricity saving takes place if its actual specific consumption is comparable with progressive norms developed on the basis of introduction of new equipment and technology into production, rational operation of technological equipment and electrical installations. One of the main directions of improvement of rationing is the choice of rationing structure taking into account the objective assessment of actual energy resources saving. The article shows the rationing of electricity consumption in the production of finished products at the enterprises of ferrous metallurgy, in particular, at the electric steelmaking industry. The results of the analysis of the state of electricity consumption rationing in the ferrous metallurgy industry are given. The developed multilevel structure of electricity consumption rationing based on the results of the study, which gives the prospects of determining the possibility of energy saving at the object under consideration, is described.

Understanding the water-energy nexus in urban water supply systems with city features

The water-energy nexus has been introduced into urban water supply systems (WSSs) to improve the current plight of scarce resources and greenhouse effect in recent years. Urban water-energy integrated management is limited by the characteristics and reality of each city. In this paper, we characterize the comprehensive influence factors of energy use in China urban WSSs including geographic differences and city forms. The results indicate that the pressure of pipeline network and plain area ratio restricted by geomorphology would significantly impact the energy consumption during conveyance and distribution stage. For the city form aspect, the total volume of urban water supply and the leakage rate of pipeline networks play important roles in energy consumption of urban WSSs in China. In this study, the specific electricity consumption in WSSs was quantified, and several factors affected by city features which show strong correlation with energy use were determined. The results are of great significance to the energy saving in water supply systems in urban areas.

A study on the influence of the ratio of pig iron and metal scrap in the of electric melting charge on the technical and economic performances of the rail steel production

The article contains the results of the statistical study on the influence of the ratio of pig iron and metal scrap in the charge for the production of rail steel on the main technical and economic performances of the electric furnace shop. The regression curves obtained and substantiated from a technological point of view indicate a linear decrease in the specific consumption of electricity and an increase in the specific consumption of oxygen according to the parabolic law with an increase in the proportion of both hot and cold iron in the metal scrap. Also, a linear reduction in the manganese content at the tapping was observed with an increase in the proportion of pig iron in the metal charge. The dependence of the duration of melting on the ratio of the charge components in the metal scrap has a pronounced nonlinear character and indicates the presence of a pronounced minimum. The statistical model constructed on the basis of the dependencies obtained is an effective tool for optimizing the share of pig iron in the metal charge in the production of rail steel for a specific period of time, taking into account the level of prices for materials and energy carriers.

Smelting of ferrosilicum from the position of energy and technology criteria of ferroalloys electric arc furnace operation

For estimation of ferroalloy-producing electric arc furnace operation efficiency an energy and technology criteria proposed. Its physical meaning is as follows: it determines a share of energy from the current source, in particular its useful part, spent by ore reduction carbon-thermal process of a ferroalloy production (ferrosilicum, ferrochrome, ferromanganeese), taking into account heat losses and degree of extraction of the leading element into the alloy.Results of an analysis of ferroalloys smelting parameters in electric arc furnaces via carbon-thermal process by example of smelting FeSi using energy and technology criteria of ferroalloys furnace operation presented. It was shown, that while increasing values of energy and technology criteria, the specific consumption of electric power per one basic tonne of the alloy is reducing. For mid power electric furnaces that melted 75% FeSi, the energy and technology criteria of ferroalloys furnace operation corresponds to a range from 0.300 to 0.314. At the same time, the specific electric power consumption is from 9.0 to 8.6 MW∙h/t of the alloy. A satisfactory, but less efficient version of the furnace operation is the range of energy and technology criteria from 0.272 to 0.293 and specific electricity consumption of electric power varies from 9.8 to 9.2 MW∙h/t of alloy. Such a complex value can be considered as the main element of the energy and technological audit of the ferroalloy furnace facility, as well as to identify effective operating modes, analysis of usage of various types of charge materials (ore raw materials, carbonaceous reductants) and the application of innovative melting technologies.

Removal of ammonium ions from aqueous solutions using electrodialysis

We report results of investigating the processes of electrochemical oxidation of ammonium in a two-chamber electrolyzer depending on the composition of the original solutions ‒ anolyte and catholyte, current density, electrolysis duration. It is shown that the electrochemical oxidation of ammonia in aqueous solutions of ammonium sulfate proceeds at a rate of 14‒55 mg/(dm 3 ·hours) at a current density of 86.2‒172.4 A/m 2 and the starting concentrations of a given ion of 10‒120 mg/dm 3 . The rate of ammonium oxidation under these conditions increases with increasing starting concentrations of ammonium and with increasing current density. The output of oxidized ammonium for current and specific consumption of electricity for water purification from ammonium are defined based on ammonium concentrations and current density and increase with an increase in the concentration of a given ion and a decrease in current density. Ammonium oxidation rate increases by 1.66 times in solutions of ammonium sulfate ([NH 4 + ]=90 mg/dm 3 , j=172.4 A/m 3 ) in tap water, compared with distilled water. This is due to the presence of chlorides in tap water, which act as a catalyst during ammonium oxidation at the expense of the intermediate formation of active chlorine. Under these conditions, we observed complete oxidation of ammonia compared with solutions on distilled water where the residual ammonium concentrations reach 1‒3 mg/dm 3 . It is shown that the presence of chlorides in catholyte at a concentration of 30 mg/dm 3 almost does not accelerate the oxidation of ammonium. Our work demonstrated thatекек in all cases, during oxidation of ammonium, pH of solutions decreases to 6.1‒2.0, which is predetermined by the oxidation of ammonium to nitrates and the acidification of water by the formed nitric and sulphuric acids. Based on the reported results, it can be concluded that the electrochemical method is the most promising method for the extraction of ammonium ions from water. Its application makes it possible to achieve a 100 % water purification.

Damring Formation During Rotary Kiln Chromite Pre-reduction: Effects of Pulverized Carbonaceous Fuel Selection and Partial Pellet Melting

Electricity consumption is the largest cost contributing factor in the production of ferrochrome. Currently the pelletized chromite pre-reduction process (solid-state reduction of chromite) is the process option with the lowest specific electricity consumption (MWh/ton). In this process, pelletized chromite is fed into a rotary kiln at 1573 K (1300 °C), where partial pre-reduction takes place. Damring formation (material build-up) in the rotary kiln causes routine shutdowns, resulting in loss of revenue. The damring formation is possibly caused by melting of the ash of the pulverized coal used to fire the kiln and/or the partial melting of the chromite pellets. Ash fusion temperatures of twenty different samples were evaluated to assess the temperature at which the pulverized coal ash will start to contribute to damring formation. Sessile drop tests were used to assess the softening behavior of different ore types (e.g., UG2, MG, and LG metgrade), as well as softening of composite chromite pellets made from these ores. Actual damrings were also analyzed using scanning electron microscopy with energy dispersive X-ray spectroscopy. Results indicate that it is mainly the pulverized coal ash that will contribute to damring formation, and not ore or pellet softening. Multiple-linear regression was used to derive equations to predict the ash fusion temperatures of the pulverized coal ash, which can be used by ferrochrome producers to optimize pulverized coal selection.

ANALYSIS OF ENERGY PERFORMANCE OF FERROUS METALLURGY ENTERPRISES BASED ON THE SCHEME OF DECOMPOSITION

The task of determining specific electricity consumption is complex, as it is necessary to take into account a large number of factors affecting the energy indicators that determine the level of these indicators. At the same time, the type and technical condition of the main and auxiliary process equipment in the process of melting, the nomenclature of metal, the volume of consumed components of the process and secondary energy carriers (compressed air, nitrogen, oxygen and other auxiliary components), etc. are taken into account. The error in taking these factors into account may lead to deviations from the actual values of the predicted power consumption, as well as energy indicators. The energy intensity of products and the level of energy consumption also depends on changes in the structure of energy consumption, the latter depending on the need for such process components as compressed air, oxygen, nitrogen, etc. The article considers the results of the analysis of energy indicators of enterprises of ferrous metallurgy, in particular, electrosmelting shop by types of output products on the basis of decomposition scheme. It is shown that the set task is solved by means of construction of dependences of normative energy characteristics on the volume of output products, and also the final decomposition tree is formed - the tree of tasks designed to achieve solutions of energy problems, including the main one - to obtain the value of specific energy consumption. In addition, the article presents the method of determining the share of participation of auxiliary components of the technological process for example of compressed air, nitrogen and oxygen. At calculations the account of the above-stated components gives the chance to define more precisely specific expense of the electric power.

Energy consumption of Finnish schools and daycare centers and the correlation to regulatory building permit values

The national building codes set requirements for building energy efficiency in many countries. The purpose of this study was to improve understanding on the measured and calculated energy efficiency of Finnish schools and daycare centers. The study analyzed the energy consumption of 134 schools and 71 daycare centers and compared the regulatory building permit calculations to measured values for 18 case buildings. According to the results, the specific electricity consumption (kW h/(m2 a)) has increased in schools but not in daycare centers. The heating energy consumption was lower in schools, but this might be explained by that they had clearly larger gross floor area than daycare centers. When compared to the technical requirements in the building code, the actual heating energy consumption has decreased less than what the changes in the building code would suggest. The building energy consumption calculated for building permits with the monthly calculation method and standard use clearly underestimated the measured building energy consumption. The differences were larger in heating energy than in electricity consumption. In conclusion, different regulatory limit values should be considered for the two building types. The calculation methods and input data should be analyzed to ensure that they truly guide towards cost-optimal design choices.

The effect of the carbonaceous materials properties on the energy consumption of silicon production in the submerged arc furnace

Abstract The objective of this study was to use a statistical approach to determine the correlation of fixed carbon, volatile matters and moisture with the specific electrical consumption and exergy efficiency by collecting and analyzing an abundance of actual production data generated in silicon plants during the melting process of silicon produced in the submerged arc furnace (SAF). A high positive correlation (the r maximum value of 0.82) between the fixed carbon composition and the specific electrical consumption, as well as the perfect negative correlation (the r maximum value of −0.92) between the fixed carbon and the exergy efficiency were found, especially when the carbon materials contained a very high amount of graphitized carbon. Compared with the carbon materials without woodchips, the high correlation among the volatile matters, the specific electrical consumption and exergy efficiency was observed when using the carbon materials with woodchips. The influence of the proximate composition on the electrical consumption and exergy efficiency becomes stronger with the increase of the graphitized carbon content in the carbon materials. The analysis results can be used to support decisions when optimizing the proximate composition of the carbonaceous reductants in order to increase exergy efficiency and decrease electrical consumption costs, which is one of the biggest operating costs in the silicon furnace.

Development of structural diagram of automated dispatch control system for power consumption at non-ferrous metallurgy enterprises

The structural scheme of the automated control system of power consumption at the industrial enterprise is developed in the article. At the non-ferrous metallurgy enterprise, an energy inspection and a rank analysis of the electrical energy consumption of the main processing equipment were carried out. It is established that the enterprises of non-ferrous metallurgy are a complex process system consisting of a set of thousands of jointly functioning technological facilities. For the most effective estimation of power consumption of enterprises, it is reasonable to use the automated system of dispatching control of power consumption (ASDCPC). The paper presents the results of the development of the ASDCPC structural diagram that allows one to perform on-line control and management of the energy and process parameters of the main production units and the enterprise as a whole. As a result of the introduction of ASDCPC at the non-ferrous metallurgy enterprise, the consumed active power was reduced during the peak hours of the load by 20%, the specific electricity consumption - by 14%, the cost of the energy component in the cost of production of hard alloys - by 3%.

Assessment of CO<SUB align="right">2 reduction techniques of cement production in Turkey

The objective of this study is to reveal the importance of CO2 emission reduction in the cement industry for the countries with strong demand. As a case study we worked on the opportunities of reducing CO2 emissions in the cement industry in Turkey. By improving the technology, the average specific energy and specific electric consumption showed a decrease of nearly 4% and 5%, respectively over the last ten years. Process based CO2 emissions followed a slight decrease due to changes in the utilised fuel and raw material blend from 0.50 ton CO2/ton cement in 2001 to 0.45 ton CO2/ton cement in 2015. Reduction in CO2 emissions can be achieved mainly by effective waste heat recovery (WHR) systems and the increasing use of alternative fuel. When the percentage of alternative fuel usage reaches to 30.5% from the value of 2.38% 1.4 million tonnes of CO2eq reduction will be achieved.

Development of electric facilities dispatching system of metallurgical enterprise

The creation of electrical facility modern dispatching system in an industrial enterprise should be part of the overall digitalization strategy, ensuring reliable and safe operation of electrical installations, which in turn will have positive impact on the competitiveness of industrial enterprise. The article describes the principles and algorithms for constructing of electrical facility monitoring and control system on the example of metallurgical enterprise. It is described the pilot project of the plant's electrical facilities dispatching control implementation, defining ecological safety. One of the significant results of the dispatch system introduction for the sulfuric acid subdivision is to reduce technological equipment downtime by 30%. The stages and tools for improving the operational and dispatch management of the enterprise's electrical facilities are developed. The developed system of the company's electric facilities dispatching, combining information channels with three major downgrade substations, will allow solving the problems of electrical parameters, monitoring of the substation equipment state, and controlling the load of transformers, switching equipment. In addition, it becomes possible to control the specific electricity consumption of the main process equipment and efficiently to plan electricity when working in the wholesale market, as well as to increase the speed of decision- making to eliminate and prevent unwanted operating modes.

Assessment of CO<SUB align="right">2 reduction techniques of cement production in Turkey

The objective of this study is to reveal the importance of CO2 emission reduction in the cement industry for the countries with strong demand. As a case study we worked on the opportunities of reducing CO2 emissions in the cement industry in Turkey. By improving the technology, the average specific energy and specific electric consumption showed a decrease of nearly 4% and 5%, respectively over the last ten years. Process based CO2 emissions followed a slight decrease due to changes in the utilised fuel and raw material blend from 0.50 ton CO2/ton cement in 2001 to 0.45 ton CO2/ton cement in 2015. Reduction in CO2 emissions can be achieved mainly by effective waste heat recovery (WHR) systems and the increasing use of alternative fuel. When the percentage of alternative fuel usage reaches to 30.5% from the value of 2.38% 1.4 million tonnes of CO2eq reduction will be achieved.