Вплив збагачення повітря горіння киснем на стійкість кладки доменних повітронагрівачів

Abstract

The article is devoted to the problem of increasing the efficiency of blast furnace equipment. Currently, blast furnace gas does not provide the specified technological temperatures of high-temperature heat units (blast blast furnaces, heating furnaces, etc.), since its heat of combustion is insignificant (3200-3500 kJ/m3). In the work, a calculation and comparative analysis of two methods of increasing the combustion temperature is performed: enriching the blast furnace gas with natural gas (basic version) and enriching the combustion air with oxygen for the conditions of blast furnace air heaters with a temperature under the dome of 1300 and 1350 °C. It is shown that to ensure these temperatures, it is necessary to enrich blast furnace gas with a calorific value of 3228 kJ/m3 with natural gas (4.0 and 5.37%, respectively) or to enrich the combustion air with oxygen (29.4% and 32.3%, respectively). At the same time, it is necessary to have a reserve in the presence of a sufficient amount of technological oxygen. When enriching the combustion air with oxygen, the specific yield of combustion products decreases, and to maintain the same parameters of heat exchange in the nozzle of air heaters, it is necessary to significantly increase the consumption of blast furnace gas. At the same time, the total consumption of combustion air practically does not change. Calculations of the length of the torch, temperature distribution, and actual and permissible loads along the height of the combustion chamber of blast furnace air heaters were performed while maintaining a temperature under the dome of 1350 °С due to enrichment of blast furnace gas with natural gas (basic version) and enrichment of combustion air with technological oxygen. It is shown that when heating air heaters using oxygen, the length of the torch decreases and the temperature maximum shifts to the lower zone, where the static load on the refractory brick is greater. But at the same time, the permissible loads are greater than the actual loads, and thus the stability of the combustion chamber masonry will be ensured. With the current scarcity and cost of natural gas, its use is irrational. Heating the combustion components requires significant capital expenditures for the construction of a complex of heat exchangers. In some cases, there are no areas for placement of heat exchangers on existing thermal units. At the same time, devices for using oxygen are simple and cheap.