Reconstruction of furnace with walking beams SPC-2at APO "Uzmetkombinat" (Bekabad, Uzbekistan)
One of the biggest and complex projects directed to efficiency increase and cost saving is the joint project of APO "Uzmetkombinat" with the general contractor and projecting company CMI Thermline on reconstruction of the furnace with walking beams SPC-2.
The purposes of reconstruction of the furnace are:
- Improvement of technical and economic parameters of the furnace work (reduction in heat rate, reduction of heat loss with scale, increase of furnace capacity with the same gas consumption);
- Increase of reliability and overall performance of the equipment and systems of the furnace (hydrosystem, SIO, bottom beams system, automation system);
- Improvement of conditions of maintenance of the equipment and furnace systems, increase of repairability
The offered system includes modern management and full control of the furnace in structure of mill. The system carries out tracking and displays information on conditions of heating of each slab, on the basis of this information counts optimum installations of temperature of zones, as well as an optimum mode of manufacture.
The system carries out following functions:
- Geographical tracking production. The present function is engaged in updating of a map of furnaces in the process of promotion of slabs inside of furnaces (setting, delivery, promotion of slabs forward, entrance in the sector, exit from sector...). This function is connected with the database and makes the information accessible to other functions. The present function also allows to visualize the program of furnaces rolling. The database (Oracle) contains on each slab a series of data received from level 3 and information collected during the process of heating the slab.
- Tracking temperature. The present function keeps constant calculation of temperature conditions of all slabs (every minute). It uses mathematical model, which counts the average temperature and gradient of each slab, as well as its heat content. The present model uses the methods of final differences. It is model with 2 measurements. It accounts the initial condition at setting either by means of pyrometric measurement or by means of calculation. Physical properties of each steel type are kept in memory, as well as temperature function.
- Function of rate. The purpose of that function is maximum increase of mill productivity and coordination of the productivity of its various elements. This function counts the delivery signals, average speed of slabs moving, expected time of slabs heating in the furnace and in zones. The function takes into account the maximum performance of the furnace, draft group, finish group, as well as moving of bottlenecks (time of rolling, terms, minimal time of heating...) for each standard size.
- Calculation of installations. This function periodically makes calculation of all installations zones to perform optimum heating for achievement of target temperatures, but at the same time to reduce the gas input. This function determines the optimum curve of heating for each slab; then it selects the ideal conditions which will represent the ideal compromise. For each slab the factor of priority can be applied. This function also observes that the temperature does not exceed the peak value of temperature of slab surface. Strategy of heating adapts to stops of the mill and conversion of furnaces to duty gas or to the mode of furnace run-up. The present function takes into account both scheduled and off-schedule stops.
- Report function. This function makes the calculation for certain period of time (hour, change, day, month) of industrial data, work results on theoretical and real rate of delivery, quality of heating, average operation of furnace, data of management and strategy, thermal parameters, balances, efficiency, losses, results of zones work, emissions control. These results are kept in archive within a year; they can be accessed from display or after printing.
- Archiving function. This function keeps all slab history, including all curves (temperature, streams, charges, moving in furnace...). The information about rolling is kept approximately for a month. Data for last month are transferred to the 3rd level for storage.
- Function of temporary archiving. This function keeps in memory all analog and logic variables of furnaces. Access to this information is possible to receive by inquiry in the form of curves or statistical data.
- Fault signal function. This function displays in real time all signals of malfunction, or data about all other functions. It saves fault signals for last month, searches and classifies them for analysis.
- Data collection function. This function is used for processing of data received from level 1, including the control of data accuracy and tests for data fit.
- Connection function. The function provides connection between various levels, as well as inspection systems.
- Human interface. All data and results are available to operator on monitor as busy pictures and still images. There is possible to create more than 40 images.