Study on application of semi-coke in blast furnace iron smelting

    2021-06-24 22:09:22

1 Application Range of semi-coke in iron smelting system
1) Semi-coke can replace small pieces of coke. Semi-coke has obvious price advantages, and it is widely used in the blast furnace iron smelting. Especially for small blast furnace producing high purity cast iron, it is more meaningful. Generally speaking, the ash content of semi-coke is 5%-8% lower than that of coke, and contains less harmful impurities. It is the best fuel for the production of high purity pig iron. At present, the price of semi-coke is about ¥1000/t, and the coke price is more than ¥2000 /t. It is more economical to use semi-coke in blast furnace iron smelting. However, the semi-coke strength is low and it can only replace small coke, and the effect of semi-coke used in sinter is the best. Dosage is 15-30kg/t iron.
2) Semi-coke can be used for blast furnace injection. Semi-coke contains high carbon, but low sulfur, low phosphorus, and low ash content, used for injection, its replacement ratio is high, better than the effect of coal injection. But semi-coke may be more expensive than blowout coal, depending on the cost of transportation. Semi-coke need not to be ground too fine for spraying (for particle coal spraying), its hardness is higher than coal, may be hurt the pipeline wear.
3) Semi-coke can replace sintered solid fuel. At present, the state proposes to carry out comprehensive treatment of sintering flue gas, and sintering flue gas desulfurization is a mandatory index. For this, the sintering plant should pay a higher price. European iron and steel enterprises take the method of buying low sulfur content coal, no need  sintering flue gas desulfurization. Sulfur content of semi-coke is very low, China's sintering plant can also take the road of Europe, to use low sulfur content of semi-coke, reduce sintering production costs. At present, the annual output of sinter in China is about 800 million tons, and the consumption of sintered solid fuel is about 54kg/t. If semi-coke is applied, it will be used in large quantities.
4)Using semi-coke in iron system is beneficial to energy saving and emission reduction. Semi-coke has high carbon content, low harmful impurities and higher replacement ratio than coke, which can reduce the fuel ratio of iron smelting and thus reduce the energy consumption of iron smelting process. Semi-coke replaces coke, so that the use of coke is reduced, that is, the energy consumption of coking process is reduced, and ultimately the energy consumption of iron making system is reduced. This is the energy saving structure of the iron smelting system.