CO_2 Reduction by Blast Furnace Top Gas Recycling Combined with Waste Hydrocarbon Gasification

摘要

Carbon has been used for a reducing agent in the conventional blast furnace. Decreasing carbon usage by both using hydrogen source and improving the energy efficiency is the first target and CO_2 squestration is another way to cut CO_2 emission. Experimental evidences show that hydrogen substitutes the coke as a reducing agent by way of stack gas injection. Correlation shows that the coke consumption can be lowered proportionally to the effective(CO+H_2) volume. With this correlation the coke consumption in a blast furnace can be estimated while hydrogen-rich gas is supplied from the gasification of the waste mixture. In the estimation, pure oxygen was used to increase effective(CO+H_2) volume. The use of oxygen has other advantages such as increasing blast furnace efficiency and emitting nearly pure CO_2 after combustion with oxygen. By recycling the blast furnace top gas through the gasifier, the carbon utilization efficiency is increased and the top gas is also recycled to the tuyere for the purpose of raceway temperature control and the optimum blast furnace operation.