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Section 7. Technical sciences
Section 7. Technical sciences
Hoshimov Fozildzhon Abidovich, Doctor of Technical Sciences, Professor, Head of the Laboratory of the Institute of Energy and Automation, Academy of Sciences of the Republic of Uzbekistan (Tashkent) Rakhmonov Ikromdzhon Usmonovich, assistant Tashkent State Technical University (Uzbekistan) E-mail: [email protected]
Rationing of electricity production in the rolling of ferrous metallurgy
Abstract: In given to article rationing of the electric power in rolling production of ferrous metallurgy is considered questions and the analysis of resultant sizes of a specific expense of the electric power for a variety and ball rolling. Keywords: variety rolling, ball rolling, thyristors, consumption.
The main objectives of improving the efficiency of the energy economy of the industrial enterprises are the improvement of technological processes and energy production, improve equipment performance and to minimize the need for energy resources.
One of the energy-intensive industries is ferrous metallurgy enterprise, which have a number of energy-intensive basic and auxiliary shops. As we study the energy performance was reviewed by rolling mill.
In the rolling mills ofSteel Plant redistribution of ingots is implemented for rolling in various shapes and sizes. Usually in such workshops for this purpose, several mills are established, the type of which is determined by the range of rolling.
An integral part of mills are the heating device, working stands and support mechanisms for tilting, transporting, cutting and cleaning of metal.
The main consumers of electricity in the rolling shop are motors drive rollers of work stands (main drive) and auxiliary machinery. In addition, there are various units of motors, overhead cranes, pumping and ventilation systems, as well as thyristors converters, electric lighting, etc.
Power of main drive motors of rolling mills expressed thousand kilowatts. For example mill «630» and «300» on the shop floor TWS-2 Bekabad Steel Plant consists of 28 and 32 stands, depending on the process of rolling metal.
Main drive motor for the mill is characterized by significant fluctuations in the load of the regime change, depending on the process conditions, the alternation of work periods and breaks. Thus, the load peaks on reversing mills do not last more than 5 or 6 seconds for continuous 25 or 40 sec. Instantaneous overloads exceed the rated power of the engine 2 or 3 times.
Due to the high degree of mechanization of the process of rolling mill installation is required on a large number of
electric motors. The power of electric auxiliary machinery of highly mechanized modern mill reaches several thousand kilowatts.
Mechanization of rolling production is accompanied by a high consumption of electricity, which is the sum of the energy consumed by the main drive and the various mechanisms of the camp:
W , = (P , + Rdl + P ) t ,, kW • h
rol 4 rol in' ror
where Prol - average power during rolling, including the power spent in idling of mill and converting units, kW;
Pdl, the Pin - the average power of the mechanisms of long and intermittent modes, kW;
trol - rolling time, hours.
Mechanisms of long and intermittent modes are auxiliary units of mill designed for mechanization of the rolling process, ventilation systems, various pumping stations, overhead cranes, transport devices, units for cold straightening and finish rolling.
Specific consumption of electricity consumed for the production of rolled products, determined by the formula.
Erol = W/nor kW • h/ton
where П , is the number of rolled metal for the settlement
rol
period, tons.
Rational use of electricity in the rolling plant should be based on progressive norms of specific energy consumption. Progressive rate of specific energy consumption is technically feasible energy consumption required to produce one ton of ready roll in modern technology and the most advantageous mode of operation of the equipment.
Development of norms specific energy consumption is based on technical and economic calculation, which uses the test results and statistical data on the dynamics of specific power consumption. If the feasibility studies of norms of electricity consumption must be taken into account organiza-
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Rationing of electricity production in the rolling of ferrous metallurgy
tional and technical measures to reduce energy consumption. It should also take into account the increase or decrease in power consumption depending on the period of the year in the autumn — winter and spring-year-old. Energy-saving mode when rolling is associated with the maintenance of the mill in operation optimal values of heating temperature, the coefficient of friction of the metal, the magnitude of the compression pass and the rolling speed
The composition of section rolling shop ofJSC “Uzmet-kombinat” includes: linear mill “300”, mill “ШПС-40-80» -two lines, mill « ШПС -80-120» -one line.
The structure of the camp «300» includes:
— Crimp line «630» -two stand;
— Roughing line «420» -two stand;
— Fine Line «300» -two stand.
For the heating of the metal under the rolling, have two reheating furnaces with capacity of 50t/h.
On the line «630» blanks for ball mills and Long products are rolled. Ready shapes, sections, after the finishing line enter the pinion refrigerator, which produces cutting to length.
To calculate the specific consumption of electricity by shops of «Uzmetkombinat» accepted design-statistical method that is based on the analysis of statistical data for a number of years prior to the actual electricity consumption, the volume of production and the factors influencing their change.
When calculating the specific energy consumption by types and classes of products accounted for specificity of this shop.
In the rolling plant produced:
— Hot-rolled steel round: close-grade 40 mm, 100 mm and 120 mm.
— Band of hot-rolled steel of general purpose: close-grade 60h12 mm, 50h20 mm, fine-grade 50h5 mm.
— Hot-rolled steel angles, equilateral: fine-grade 25h4 mm, mm 28h4, 30h4 mm, mm 32h4, 40h4 mm.
— balls of steel grinding for ball mills, with a nominal
diameter of 68.0 mm and 104 mm.
— Hot-rolled square: the average grade-side 20 mm, finegrade side 16 mm.
Over the period of 2012 and 2013, it been studied and analyzed and mean-average actual cost of electricity and the production volume at which revealed shifts producing only one range of hire. On the basis of these data, it is determined the average power consumption and the volume of output for each range. It should be noted that due to a slight change of specific indicators of energy consumption related to the range in the production of the specific consumption of varieties accepted. Given this, we analyzed the energy performance separately on assortment and variety of rolling overall.
Below, it is given the calculation of determining the average value of energy consumption by the type of product W = (W + W + W + ... + W)/n, kW • h/shift where W1...Wn — Removable power consumption corresponding to only one type of metal, kWh/shift,
n-number of shifts for which releases one type of metal rolling.
Mean-volume products must conform to the electricity consumption at which the volume was determined mean-power consumption, considered assortment.
П = (П + П + П +... + П )/n, t/shift
av 1 2 3 n
where Пг.Пп — removable volume of produced metal rolling, corresponding to only one type, t/shift.
The average value of the specific energy consumption by the type of product has the form:
а = W /П = (W+W+W +... + Wn)/(Th + П+П+...
av av av 1 2 3 1 2 3
...+Пп), kW • h/ton
The following table shows the average monthly value of power consumption, the volume of issuance ball rolling and specific energy consumption by months in 2013.
Table 1. - The resulting values of the specific energy consumption for ball rolling
Range The average monthly power consumption, ths. kW • h Average monthly production volume in tons The average specific energy consumption, kWh/t
Ball rolling 0 68, 0 100, 0 120
0 100 223,97 3555,22 63
0 68 534,64 7034,83 76
0 120 203,27 4143,41 49
in total 961,88 14733,47 65
average 320,63 4911,16 65
Ball rolling 0 40
0 40 75,60 504,05 150
The table shows that the value of the specific energy con- particular, the specific energy consumption of the ball marks sumption varies within wide limits, not only by types of manu- 0 40 is more than three times energy-intensive than the spe-
factured products of shop, as well as within the same range. In cific consumption of ball marks 0 120
Table 2. - The resulting values of the specific energy consumption for variety rolling
Range The average monthly power consumption, ths. kW • h Average monthly production volume in tons The average specific energy consumption, kWh/t
1 2 3 4
Area 40x4 41,08 331,76 124
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Section 7. Technical sciences
1 2 3 4
Area 32x4 19,53 165,54 118
Area 25x4 43,98 318,34 138
Area 35x4 44,58 484,12 92
Area 40x5 27,28 228,96 119
Area 30x5 18,35 1978,99 103
Square 16x16 17,12 160,37 107
Square 20x20 11,70 116,28 101
Band 40x5 25,70 190,24 135
Band 36x6 12,46 200,50 62
Band 40x10 27,33 232,11 94
Band 50x5 8,33 94,62 88
Analysis of the tables shows that the specific energy consumption by types of products is very different. In particular, the specific energy consumption of ball rolling 0 of 40 is greater three times than the ball rolling 0 100. Not accounting of energy intensity products range of the rolling mill will lead to inaccurate calculation of energy consumption over the forecast year or accounting period.
Conclusions:
1. It has been established that most of the carbon and low alloy steels decrease the heating temperature during the rolling by 1° C leads to an increase in the specific energy consumption at 0.5-0.8%.
2. Specific power consumption for the production of various types and sizes of the rolling are significantly different and the ratio of maximum to minimum values reaches 70%.
References:
1. Hoshimov F. A., Allayev K. R. Energy saving at the industrial enterprises. T.: “Fan", 2011.
2. Hoffman G. B. Rationing consumption of energy and power balances of the industrial enterprises. M.: Energy, 1966.
3. Hoshimov F. A. Methodical bases of energy saving in the industry. Tashkent, 2010.
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