RESEARCH ON THE EFFICIENCY OF THE USE OF PROCESS OXYGEN TO ENRICH THE COMBUSTION AIR IN METALLURGICAL HEATING EQUIPMENT
The purpose of the paper is to develop a method for determining the efficiency of the use of process oxygen for the enrichment of combustion air in the metallurgical heating equipment.
Methods. In the course of the research, the following was used: mathematical model of the hot-blast stove, which allows to determine the consumptions of fuel, combustion air, and flue gases, the changes of flue gas and air blast temperatures along the checker chamber at given design parameters and air blast consumption; the method of calculation of fuel combustion processes and the calorimetric temperature of fuel.
Results. The study of the thermal operation of hot-blast stoves allowed to determine that the use of process oxygen for the enrichment of combustion air provides the operation of hot-blast stoves and the preset blasting temperature when the oxygen content in the combustion air is 26 %, but requires an increase of the blast-furnace gas consumption by 32 %. For hot-blast stoves, the specific cost of heating increases by 20.9%, which makes the implementation of this measure economically impractical. The study of changes in the energy efficiency of the continuous furnace and the steam boiler, which use atmospheric or oxygen-enriched air for combustion process, allowed to determine that the efficiency of use of oxygen in the continuous furnace is much higher than in the boiler. When the oxygen content in the combustion air increases up to 31 %, the fuel saving for the continuous furnace is 11.6 % and the specific consumption of process oxygen is 6.28 m3 per 1 m3 of saved natural gas. At the same time, these figures for boilers respectively are 1.7 % and 48,67 m3/m3.
Scientific novelty. Using mathematical modelling of hot-blast stoves operation, it was proved that the use of process oxygen for the enrichment of combustion air provides the predetermined air blast temperature and natural gas saving, but requires a significant increase of blast furnace gas consumption. An analytical dependence that substantiates the maximum cost of process oxygen for its break-even use in the hot-blast stoves was established. For the furnace and steam boiler, both of which use the atmospheric air enriched with process oxygen for combustion process, the following analytical dependencies were determined: the consumption of process oxygen for saving 1 m3 of fuel; the maximum cost of process oxygen, in which its use does not lead to an increase in the total cost of fuel and process oxygen.
Practical significance. The developed method for determining the efficiency of the use of process oxygen for the enrichment of combustion air can be used in the energy management systems of metallurgical plants to control the thermal balance of the plant and chose the units, in which the use of temporary excess of process oxygen allows to avoid its losses and provide the greatest savings.
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