New Generation Blast Furnace with Low Coke Consumption
22 February 2010
Blast furnace ironmaking is the major process for iron production. It is a well-established and highly efficient process in terms of energy and exergy consumption. Further development of blast furnace ironmaking targets decreasing coke consumption and overall CO2 emission.
The concept of new generation blast furnace is proposed. The operation of a new generation blast furnace is based on three major measures: complete combustion of injected carbonaceous materials from the tuyeres; complete indirect reduction of iron oxides; and recycling of top gas CO in combination with nitrogen free operation. It is estimated that the coke consumption in a new generation blast furnace can be reduced to about 70 kg/THM.
Under the condition of complete indirection reduction, primary slag will not form in a blast furnace, so that the cohesive zone will be eliminated which greatly improves the permeability of the blast furnace stack.
CO separated from the top gas can be injected through the tuyeres and into the isothermal zone. The fraction of CO injected through the tuyeres and into the isothermal zone can be adjusted to control the theoretical flame temperature in the raceway.
The proposed new generation blast furnace has a higher exergy efficiency and lower carbon consumption, but the net energy consumption is marginally higher than in the conventional blast furnace. Preheating of the CO injected through the tuyeres using a low temperature heat source further increases the efficiency of blast furnace operation.
The Advantages of the new generation blast furnace include:
- Decreased environmental issues due to production of coke
- Extended life time of coke production batteries
- Decreased dependence of blast furnace operation on metallurgical (coking) coal
- CO2 generated from blast furnace is ready to store for reduction of greenhouse gas emission
- No more high temperature blast stoves to be maintained
- Significant reduction of the ironmaking costs
Above advantages of the new generation blast furnace make the blast furnace ironmaking a sustainable technology.