The blast furnace smelting technology need coke, it plays an important role during smeltingprocess, not only supply heat energy, but also act as reducing agent forreduction of iron ore, it also has the function to maintain permeability ofstock column skeleton. The price of coke keep increasing, PCI system can reducecoke ratio and production cost, it is a revolutionary development of modernblast furnace smelting.
1、The significance of PCI system:
Substitutecoke with pulverized coal and reduce cost.
Itbenefits for high blast temperature and oxygen enrichment technology
Itbenefits for furnace condition adjustment and improvement of blast furnacesmelting process.
Itcan solve the problem of coke shortage.
Itcan reduce production cost.
2、Therequirement for PCI system
Pulverized coal preparation equipment
The source and requirement of dry gas
Thetemperature of dry gas is below 350℃ when feed into coalmill.
Thetemperature of dry gas is usually controlled according to the outlettemperature of coal mill, the lower limit guarantee the temperature at baghouse collector is higher than dew point, the higher limit is considered basedon safety anti-explosion. There is no limit for anthracite, the soft coalusually can’t exceed 120℃~130℃,the lignite can’texceed 100℃。
Coal mill system
Ball mill
Advantages:well-adapted to various coal types, safe and reliable, less maintenance work.
Disadvantages:Great noise and high power consumption, large dimension.
Medium-speed mill
Advantages:low power consumption and noise, explosion-proof property, good performance ofregulation and homogeneity.
Disadvantages: sensibleto change of coal type.
Pulverized coal injection equipment
Pulverized coal injection tank
Double-tank paralleling type: the upper part is coal storage tank, thelower part is pulverized coal injection tank. The advantages are accurateweighing and high reliability, the disadvantages are large occupied area, muchmore equipment, high investment.
Three-tank single-row type: the upper part is collection tank, themiddle part is coal storage tank, the lower part is injection tank. Theadvantages are small occupied area, simple-structure device and less equipment,low investment, the disadvantages are hard connection between coal storage tankand injection tank affect accuracy of weighing.