Method and apparatus for improved use of primary energy sources in integrated steel plants

A method of increasing pig iron and/or liquid steel production in a blast furnace of an integrated steel plant while reducing CO2 emissions per ton of pig iron, as compared to conventional integrated steel plants, which plant comprises a blast furnace for pig iron production, an oxygen converter for converting the pig iron into steel, a coke oven for the production of coke charged to the blast furnace, and a direct reduction reactor for producing direct reduced iron, said method comprising

• converting coal to coke in the coke oven;
• forming a first gas stream having a hydrogen content of at least about 50% by volume and a carbon monoxide content of less than about 10% by volume by withdrawing and conditioning the temperature and pressure of the coke oven effluent gases;
• charging iron ore, the coke and air to the blast furnace and converting the iron ore to pig iron;
• charging the pig iron and oxygen to the oxygen converter and converting the pig iron to steel;
• forming a second gas stream having a hydrogen content of less than about 10% by volume and a carbon monoxide content of at least about 50% by volume by withdrawing and conditioning the temperature and pressure of oxygen converter effluent gases;
• forming a third gas stream having a reducing potential greater than about 0.6, a hydrogen content greater than about 30% by volume, and a carbon monoxide content greater than about 30% by volume by mixing the first and second gas streams;
• forming a fourth gas stream by combining at least a portion of the third gas stream with at least a portion of regenerated gas effluent from the direct reduction reactor;
• heating the fourth gas stream to a temperature of greater than about 850° C.;
• reducing iron oxide-containing solid particles in the direct reduction reactor to metallic iron in the form of direct reduced iron by introducing the solid particles and the heated fourth gas stream into the direct reduction reactor;
• forming a fifth gas stream by withdrawing reacted gas from the direct reduction reactor;
• forming a sixth gas stream with regenerated reducing potential by removing water and carbon dioxide from at least a portion of the fifth gas stream and the separated carbon dioxide is collected;
• using at least a potion of the sixth gas stream in the formation of the fourth gas stream;
• and charging direct reduced iron from the direct reduction reactor to the blast furnace,
• wherein one portion of the gas effluent from the direct reduction reactor is used to heat air injected into the blast furnace, and another portion of the gas effluent from the direct reduction reactor is introduced as fuel into the coke oven.