Experience of co-injection of pulverized coal and natural gas into blast furnace hearth under the conditions of PJSC "KAMET-STEEL"

Abstract

The article provides an analysis of the practical and analytical results of the methods of co-injection of pulverized coal and natural gas into the hearth of blast furnaces by American researchers and practitioners. The analysis shows the advantage of supplying natural gas, as well as pulverized coal, through the lance into the blow channel of the tuyere device. Practical results obtained for the first time in Ukraine of co-injection of pulverized coal and natural gas into the hearth of a blast furnace in unstable charge and fuel conditions of PJSC "KAMET-STEEL" are presented. Practical experiments have proven the efficiency of such injection when fuel additives are injected onto separate lances into the blow channel of the tuyere device, and the natural gas lance is withdrawn so that its combustion occurs before the injection of pulverized coal into the blow channel. The effectiveness of the practical application of the method of co-injecting pulverized coal and natural gas into the hearth of a blast furnace is expressed in a reduction in the specific coke consumption by 10.3 kg/ton of cast iron (or 2.85 %) at a consumption of pulverized coal — 153.4 kg/ton of cast iron and natural gas — 24.5 m3/ton of cast iron. The results obtained allow us to recommend this method of injecting fuel additives under acceptable price conditions, as well as at other metallurgical plants, especially those operating with better conditions for ensuring high temperatures of hot blast — more than 1050 °C. As a result of the analytical studies performed, it was established that: nozzles with two inlets for natural gas and pulverized coal, ensuring the introduction of natural gas into the blast channel before pulverized coal, contribute to the maximum burnout rate of the latter in the blast flow; with this injection method, more methane natural gas is burned, more heat is released due to the combustion reaction, which leads to an increase in the blast temperature at the outlet of the tuyere.