método de operação de alto-forno, método de combustão de gás de baixo valor calorífico para o mesmo, e instalação de alto-forno

摘要

Air or oxygen-enriched air is blown into a blast furnace from a tuyere, and a preheating gas is injected into the blast furnace from a gas injection portion (A) disposed in a shaft portion. The gas injection portion (A) has a gas combustion and injection device (a). In the gas combustion and injection device (a), an opening to inject each of a fuel gas and a combustion-supporting gas or to inject a premixed gas of the fuel gas and the combustion-supporting gas in such a way that a swirling gas flow occurs in the combustion chamber is disposed in an inside wall surface of a tubular combustion chamber. An end of the combustion chamber is communicated with the inside of the blast furnace. A combustion gas of the gas combustion and injection device (a) is injected as a preheating gas into the blast furnace.