Thermal Engineering Laboratory preparation of metallurgical raw materials VNIIMT A Methodology for Integrated Study and Optimization of the Heating Systems in Traveling grate furnaces
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In pellet production, it is possible to significantly improve the performance of the equipment and to eliminate ineffective approaches by means of a newmethodology for the integrated investigation and optimizationof the heating parameters in the conveyerroasting of iron-ore pellets. This methodology includesanalysis of the heating equipment and an optimization criterion based on a systems approach; integrated methods of investigating individual system componentsand the technology as a whole; improved mathematicalmodels; the formulation and solution of optimizationproblems; and engineering principles for an automatic control system based on up-to-date information technology.
Fig 1. Traveling grate pelletizing plant VNIIMT
Fig 2. Straight grate pelletizing plant VNIIMT
Fig 3. VNIIMT Traveling grate furnace
Fig 4. VNIIMT Traveling grate machine for iron ore pellets heat treatment
Fig 5. Traveling grate furnace
Fig 6. Traveling grate machine
ASPECTS OF THE PRACTICAL USE OF VNIIMT METHODOLOGY TO OPTIMIZE THE HEAT-ENGINEERING SCHEMES EMPLOYEDON CONVEYOR-TYPE ROASTING MACHINES (traveling grate furnaces, straight grate pelletizing plant)
Results are presented from practical application of VNIIMT methodology for optimizing the heat-engineering schemes of conveyor-type roasting machines at different combines. Technical innovations that will improve the performance indices of these traveling grate pelletizing plant are presented. One example cited is the modernization of traveling grate furnace No. 5 at the Sokolovo-Sarbaiskii Mining-Beneficiation Association, which increased the productivityof the pelletizing plant by 24.6%, reduced the consumption of natural gas by more than half, and lowered electricpower consumption on the draft equipment by 21.3%.
Comparison of Heating Systems in Conveyer Roasting Machines (traveling grate furnaces, straight grate pelletizing plant)
The heating systems of traveling grate pelletizing plants for iron ore pellets are compared by a methodology developed at OAO VNIIMT. Each system has further scope for improvement
Design of Optimal (Energy-Efficient) Roasting Systems
(traveling grate furnaces, straight grate pelletizing plant)
Power consumption in the gas-transport system during pellet production in conveyer roasting machinesaccounts for 100% of the fuel (natural-gas) costs. Therefore, reducing power consumption in the roastingmachines is of great importance. Moreover, modernizingthe technology in this way provides a reserve of power for existing gas-transport systems and permitsincrease in productivity of the machine by the intensification of heat treatment, which is also important.
On the basis of systematic analysis using mathematical models, basic design principles for the thermal systemsof pellet-roasting machines with minimum power consumption have been developed.
Fig 7. Traveling grate pelletizing plant optimized by VNIIMT for iron ore pellets. Optimal control systems for gas supply from cooling one 2 to drying zone 1 (a) and from the roasting (Ro) and ecuperation (Re) zones to the heating zone (b
Fig 8. Traveling grate pelletizing plant optimized by VNIIMT for iron ore pellets. Nonoptimal gas supply from the cooling zone to the as–air chambers of drying section D1 (a high-pressure one) and to the hearth of drying section D2 (a low-pressure one) by means of a single gas-transportation system T1
Fig 9. Traveling grate pelletizing plant optimized by VNIIMT for iron ore pellets. Gas transportation from hearth and gas–air chamber: a) nonoptimal design with a single gas-transportation system; b) optimal design with two gas-transportation systems.
Improving the Control of Pellet Heat Treatment in Conveyer Roasting Machines (traveling grate furnaces, straight grate pelletizing plant)
Improvements in the control of pellet heat treatment in conveyer roasting machines are considered. It is shown that the consumption of power and natural gas may be reduced, and the productivity may beincreased, by means of various control subsystems, including optimal control of the process and parameter stabilization.
Improving the Productivity of a Lurgi Roasting Machine
(traveling grate furnaces, straight grate pelletizing plant)
The experimental data show that the Lurgi traveling grate machine has great scope for increase in burner anddraft-unit power. Mathematical simulation permits the development of various options for the thermal system,with gradual increase in pellet output from 3.2–3.5 to 4.5 million t/yr. An output of 3.7 million t/yr may be achieved without modernizing the machine, by adjusting the conditionsof pellet roasting. Pellet outputs of 4.0 and 4.5 million t/yr are obtained by increasing the workingarea (specifically, by lengthening the traveling grate furnace by half of a gas–air chamber, i.e., 12 m2); enlarging theraw-pellet bed from 350 to 380 and 425 mm, respectively; installing an additional draft unit for pellet cooling;and correcting and adjusting the calculated temperature and aerodynamic conditions of heat treatment.
Improving the Performance of the Roasting Machines (traveling grate furnaces, straight grate pelletizing plant) at AO SSGPO
The modernization of the heating system for traveling grate pelletizing plant 5 at AO SSGPO, with specified pellet quality,increases the productivity by 24.5 t/h (24.6%), reduces the natural-gas consumption by 56.3%(19.3 m3/t), and reduces fan power consumption by9.9 kW-h/t (21.3%). Thus, with improvement of the heating system and modernization of the OK-108/116 traveling grate pelletizing plant, their performance approaches currentglobal levels.
Fig 10. Traveling grate pelletizing plant at SSGPO for iron ore pellets.
Fig 11. Traveling grate pelletizing plant at SSGPO after modernization by VNIIMT for iron ore pellets.
Fig 12. Traveling grate pelletizing plant at SSGPO after modernization by VNIIMT for iron ore pellets. Results of measurements of the temperature distribution in the layer of iron ore pellets over the length of the traveling grate pelletizing plant. (1) in hearth; (2) at gratings; (3) at exit from gratings; (4) in hearth according to stationary thermocouple readings; (5) in the gas–air chambers according to stationary thermocouple readings.
Fig 13. Results of measurements of the temperature distribution in the layer of iron ore pellets over the length of the traveling grate pelletizing plant.
See more... Pellet Heating on Modernized OK124 traveling grate furnace
See more...Optimizing the Parameters of traveling grate furnaces (straight grate) 1–8 at AO SSGPO
See more...Design, Drying, and Heating of Hearth and Transfer Collector in Modernization of OK124 traveling grate furnace (straight grate)
Increasing the Productivity of OK-306 Traveling Grate Machine 1 at OAO Lebedinskii GOK, Producing Oxidized Pellets
Mathematical simulation based on monitoring data for traveling grate pelletizing plant 1 at OAO Lebedinskii GOK permits the correction of the thermal system, including organization of pellet cooling by cold (atmospheric) airover the whole cooling zone, with corresponding increase in the productivity; the area freed up in this way is added to the pellet-heating zone. The calculations also permit redistribution of the useful area of themachine between technological zones; maximum utilization of the blast units; redistribution of the numbersof gas–air chambers in different blast units; correction of the temperature and aerodynamic conditions; andadjustment of burner operation.
Fig 14. Temperature and pressure distribution over the length of traveling grate plant (baseline state): (1) pressure; (2, 3) gas temperatures on entering and leaving the bed; (4,5,6,7) temperatures at the top and middle of the pellet bed, at the bed–baseboundary, and at the bottom of the base
Fig 15. Results of calculations of the temperature distribution in the layer of iron ore pellets over the length of the traveling grate pelletizing plant. Temperature and pressure distribution over the length of traveling grate (state after modernization)