Efficiency of co-injection of pulverised coal and natural gas in blast furnace production conditions with variable fuel and raw material

Abstract

This article presents, for the first time in Ukraine, practical results of effective co-injection of pulverised coal (PCI) and natural gas (NG) into the hearth of a blast furnace (BF) under unstable charge and fuel conditions. Practical experiments have proven the maximum efficiency of such injection when fuel additives are injected onto separate lances into the blow channel of the tuyere device, and the NG lance is withdrawn so that its combustion occurs before the injection of PCI into the blow channel. In this case, maximum heating of PCI in the gas-air blast flow and its maximum burnout rate are achieved. The effectiveness of the practical application of the method of co-injecting PCI and NG into the hearth of a BF 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 PCI – 153.4 kg/ton of cast iron and NG – 24.5 m³/ton of cast iron and the specific coke consumption by 2.4 kg/ton of cast iron (or 0.60%) with consumption of PCI – 108.9 kg/ton of cast iron and NG – 26.2 m³/ton of cast iron in conditions of co-injection not at all air tuyeres. 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.