Application of blue semicoke in ironmaking system

    2022-06-24 12:28:48

On May 27th, the webinar on the application of Lantan in the field of iron and steel (metallurgy) was held in the form of video. The conference was co-hosted by Lantan Branch of China Coal Processing and Utilization Association, Jiangsu Iron and Steel Industry Association and Shenmu Lantan Industry Service Center.
Objectives of this meeting: Aimed at further promoting China's iron and steel metallurgy industry actively adopt the low rank coal points classification using the new products, charcoal, expand the scope of rich resources of low rank coal clean utilization, part of complementary and alternative resource scarce tight coking coal resources, reduce the fuel and the cost of raw materials of iron and steel metallurgy industry power energy conservation and emissions reduction of iron and steel metallurgy industry and clean production level of ascension.
Under the influence of the service situation, the world economy falters, the frequent energy crisis, as the metallurgical industry necessary coke, coal prices are high, the cost and environmental protection pressure is increasing, seeking more economic, clean and environmental protection energy substitutes, reduce the cost of metallurgical enterprises and environmental protection pressure has become the current more urgent task.
Blue charcoal, also known as semi-coke, is coal conversion products, with high fixed carbon, high specific resistance, high reactivity, low ash, low aluminum, low sulfur, low phosphorus and other advantages. The disadvantage is that the strength is poor, because of its rich resources, the price is far lower than metallurgical coke, to replace metallurgical coke, LAN charcoal coal or become one of the effective means of reducing cost and efficiency, reducing waste emission reduction.
The application of blue carbon in ironmaking system mainly includes the following aspects:
1. Replace coal powder and coke powder with blue charcoal for sintering
The reactivity of blue charcoal powder is obviously better than that of coke powder and anthracite. The combustion start temperature and end temperature are low, the combustion temperature range is narrow, the gasification start temperature and end temperature are low, and the gasification temperature range is narrow, indicating that the reactivity, combustion and gasification performance of blue charcoal are better than that of coke powder and anthracite. At the same time, blue carbon has lower ash and total sulfur content, which is helpful to reduce the energy consumption of sintering flue gas desulfurization and the damage of sulfur dioxide gas to equipment and environment. The useful components CaO,MgO and FeO in the ash of blue charcoal are high, which can supplement the raw material and flux of sinter. MgO in ash is beneficial to improve the reduction strength of sinter and the melting performance of slag.
Sintering experiments show that the sintering process to choose appropriate proportion of coal particle size and replace coal powder, coke powder, can effectively improve sintering machine vertical sintering speed, improve the sintering production efficiency, reduce sinter FeO content, improve sinter reduction performance, improve the taste, and using the sinter mineral composition and structure of carbon is more even, ferrite content is high, the glass content is less, Low temperature reduction reduction rate is low, medium temperature reduction degree is high.
Fly in the ointment is that due to the good reactivity, combustion of carbon fast, cause the fuel particle size, moisture and the change of negative pressure sintering parameters, such as sensitive, the production of large scale with LAN charcoal, charcoal particle size, sintering material should be paid attention to the reasonable collocation of the negative pressure in water, sintering, prevent too fast or incomplete combustion, affect the quality of sinter.
2, to orchid charcoal instead of blowing coal powder
First of all, orchid carbon has high reactivity, high fixed carbon, high calorific value, low ash content, low sulfur and phosphorus content, so that orchid carbon is more suitable for blast furnace spraying, secondly, orchid carbon explosive weak, high ignition point, good grinding. In terms of safety and production efficiency, it is also more suitable for blast furnace injection. Finally, because of the reactivity, combustion and gasification performance of orchid carbon are better than coal powder, so the spray orchid carbon is more conducive to the complete combustion of the spray in front of the tuyere, improve the combustion rate, but also to improve the spray ratio, reduce this section of coke.
3, to orchid charcoal instead of coke into the furnace
Coke into the furnace, in the domestic has been a common blast furnace operation, coke is a small piece of coke screened out in the metallurgical coke, the number is limited, so in recent years with the popularity of coke into the furnace, the price of coke is also high bamboo flowering. The advantage of orchid charcoal substitute coke into the furnace lies in: orchid charcoal reactivity is good, the initial reaction temperature and intense reaction temperature are lower than coke, so that in the blast furnace, orchid charcoal prior to coke carbon dissolution reaction, protect the large coke. At the same time, because of the fast reaction rate of lanchar, it can promote the indirect reduction reaction of massive zone, improve the preheating and reduction of ore, reduce the direct reduction reaction, reduce the coke ratio. In addition, due to the good reactivity of orchid carbon, it can ensure that the full reaction is consumed before the orchid carbon drops to the dead column, avoiding the small particle orchid carbon into the dead column, affecting the permeability of the dead column, which also provides favorable conditions for further improving the amount of orchid carbon.
The disadvantages of LAN charcoal instead of coke into the furnace are: Carbon of the cold and hot state strength is worse than coke, in the process of transportation, its storing and loading, inevitably produce more powder, the powder charging too much will affect the permeability of stock column, so in the LAN charcoal substitute nut coke charging, can choose grade a relatively large some of charcoal, decrease as far as possible whilst frequency, optimizing the loading process, in order to reduce the powder charging.
In short, instead of coke, coal, blue carbon into the ironmaking system has its advantages and has its difficult to overcome shortcomings, but the authors section, coke, high-quality, low consumption, environmental protection is the unswerving pursuit of ironmaking, grasped the nettle of ironmaking are proud spirit, though, the LAN charcoal generally enter the ironmaking system replace coke and coal, there are more equipment, technology, operation and cognitive barriers, But think a few years ago coke into the furnace encountered resistance, these difficulties and what!