SU1071653A1 - Method for roasting iron ore pellets - Google Patents

Abstract

METHOD FOR BURNING IRON OILS, including feed of COAL with a particle size of 0.01-0.10 NW c. 1–20% by weight and injecting finely ground solid fuel. In the process of pellets in the coolant flow in an amount (in carbon) of 420 kg / ton of okrapia, it is also in order the finished product, when the content of volatile in solid fuel 1.5-2.5% of the ratio of the consumption of solid fuel in the pellets and in the flow of coolant support equal to 1:

Description

sd

The invention relates to the preparation of iron ore raw materials in the ferrous metallurgy, namely, to the production of pellets. Methods are known for using solid fuels for burning iron ore pellets, including: 11 e. submission to the mixture of solid fuel with a particle size of 0.01-0.10 mm in the amount of 1-20% of the weight of the mixture SC. The disadvantage of these methods are: the need to obtain a reducing gas in a special device, which complicates the design of the unit, the production of finished products in the form of a cake, which makes it necessary for the NtJM to grind it and, as a result, complicates the process, insufficiently effective use of fuel as a substitute for scarce natural gas. gas. These disadvantages are partially eliminated by injecting solid fuel into the forge, together with the flow of heat-transfer agent. The closest technical solution to the present invention is a process of burning iron ore pellets, including the supply of coal with a particle size of 0.01–0.10 mm in quantities of 1–20% by weight and injection of finely ground coal into the layer of pellets in a heat carrier stream. carbon 4-20 kg / ton of pellets. The disadvantage of this method is the absence of a hard material reducing agent directly into the bulk. start. As a result, on the one hand, due to the lack of internal heat sources in the body of the piece, the development of heat and mass transfer processes in the central part of the pellet slows down and the specific productivity of the firing equipment falls. On the other hand, cTOpoffij ,. in the center of the piece, the processes of reducing iron oxides do not develop and the quality of the finished product deteriorates. In addition, the insufficiently effective use of solid fuels as a substitute for scarce natural gas is also inherent in the color method. The aim of the invention is to increase the efficiency of use of solid fuels and to improve the quality of the finished product. The goal is achieved by the method of burning iron ore pellets, which includes feeding into the mixture coal with a particle size of 0.01–0.10 mm in an amount of 1–20% by weight and blowing finely ground solid fuel into a layer of pellets in the heat-transfer stream in the amount of (carbon 42 (kg / t okat isy), when the content of volatile solid fuel is 1, B-2.13%, the ratio of solid fuel consumption in the OKeTrfiKiieft mixture and heat carrier flux is equal to 1: (1, 40U, moreover, with an increase in the volatile content in solid fuel from 2.5% for every 5% fuel consumption in the stream the heat carrier is reduced from 1.05 to 0.02-0.07 from the consumption of solid fuel, in the charge of pellets. The supply of solid fuel in the amount of carbon 4-20 kg / ton of pellets in the inter-piece pores of the layer in the flow of the coolant provides, first , supply of heat to the specified layer horizons and, therefore: their accelerated heating, secondly, the reduction of iron oxides located at the surface of the pellet body, due to direct contact with the solid reducing agent, thirdly, the removal of active oxygen from the coolant using it for Zhiganov portion of the solid fuel and as a consequence, T reating a layer reducing pellets or neutral atmosphere. The method also provides for the supply of solid fuels to the charge with oxycution,. those. directly into the volume of the piece. This ensures, firstly, the accelerated development of mass and heat transfer processes in the entire volume of the piece, secondly, the direct contact of solid reducing agent and iron oxides, and, consequently, their intensive reduction. In the absence of active oxidation. Therefore, dividing the flow of solid fuel into two (the fuel charge and heat carrier fuel provides forced heat treatment of both the central and peripheral portions of the pellet on all layers of the layer. The requirements for the fuel to be included in the charge and the heat carrier stream are different from each other. The charge of pellets is more expedient to use fuel with a high content of volatile, taking into account the role of the latter in the reduction processes. The inclusion of solid fuel with a high content of volatile substances in the flow of the heat transfer medium It is considered to quickly burn out and, as a result, to lose the iron oxide process for the reduction process. Therefore, as shown by experimental data, each grade of solid fuel with 1m volatile content at the same total fuel consumption corresponds to its specific, ensuring maximum effect ratio; The charge fuel is a coolant fuel. Thus, when the volatile content is 1.5-2.5%, the ratio of solid fuels a fed to the charge of pellets and the coolant flow should be 1: (1.05-1.40KVerdi .in fuel coolant flow (less than 1.05 of the amount of fuel in the charge pellet) .ne ulu-chshaet ac tive use reducing gas (coal volatiles, but reduces the amount of heat supplied to the lower layer horizons, contributing to their nedoobzhi gu. A large supply of solid heat carrier fluids (more than 1.40 of the amount of fuel in the charge of gold) contributes to the corresponding lack of solid reducing agent in the pellets and also leads to a decrease in the quality of the finished product. The increase in volatile content in coal, starting from 2.5% for every 5.0% (which corresponds to the volatile content in traditional fuel), should be accompanied by a decrease in the amount of fuel included in the heat carrier flux, starting from 1.05 to 0, 02-0.07 from the consumption of solid fuel in the batch is reduced; With a lower decrease in fuel consumption to the coolant flow, for every 5% of the estimated 1-year years (less than 0.02 units of the amount of fuel in the charge of pellets) reducing agent (volatile burned in the furnace) and decreases utilization efficiency. solid fuel. At a lower level of the fuel consumption research institute in the heat carrier flow for every 5% volatile increment (more than 0.07 units of the amount of fuel in the pellet mixture), the effect of using volatile coal is no longer improving, and the chemical activity of the heat carrier is noticeable. The essence of the invention lies in the simultaneous creation of internal sources of heat in the mezkhuskovye porx layer and directly in the body of the piece by incorporating solid fuel into the mixture of pellets and the heat carrier flow filtered through the layer at an optimal mass ratio of these flows. The method is carried out in the following way. Solid fuel with an average particle size of 0.074 V in an amount of 3.0% by weight of the mixture is included in the mixture of pellets before the pelletizer. As solid fuel, for example, anthracite with a volatile content of 2.5% and coal for fuel are used. mass - 60%. Applied to the OK-108 machine with a capacity of 100 tons / h of raw pellets, the consumption of solid fuel included in the charge will be 0.03 -100 3 tons / h. After the pelletizer, raw ore fuel oats are fed to the kiln conveyor machine, which is subsequently subjected to day, heated, fired and cooled, fueling devices of heating and firing zones are fed to fuel (for example, natural gas) and recirculation gases with an oxygen content of 18%, mix these streams and burned in the furnace of the machine. Finely divided solid fuel with an average particle size of 0.2 mm is blown into the resulting coolant. The correlation of the fuel to the fuel-coolant blend with the content of volatile in the coal is set equal to 1: 1.05. Then the consumption of the fuel included in the coolant flow will be 3-1.05 3.15 t / h or carbon 3.1 3.15 1 , 9 t / h (or 19 kg per ton of pellets. The resulting coolant with solid fuel is filtered through a layer of pellets, exposing them to strengthening firing due to the physical heat of the coolant and the chemical energy of the solid fuel in the coolant. Simultaneously hardening subject central learning Pellets of the body of pellets at the expense of chemical energy of the coal charge. The total consumption of solid fuels for the process will be 3.0 + 3, 15 t / h. After calcination, the pellets are cooled in a neutral or effective medium. I The chemical composition of solid fuels (carbon content, volatiles) are determined by chemical analysis of the next batch of raw materials and are occasionally monitored during the operation of the roaster. The average particle size of the fuel flows is controlled by standard (sentimental) analysis and is controlled by changing the parsimeters of work from grinding equipment. The amount of fuel fluxes and other components of the charge is controlled by standard weight gauges and controlled by serial 1G dosing units. When using pellets for firing another type of fuel, such as lean coals with a volatile content of up to 30% and carbon per working mass of 40%, the process is adjusted as follows. The amount of solid fuel included in the coolant flow is reduced from 1.05 from the charge fuel to 0.05 units for every 5% (starting from 2.5) volatile increments, i.e. 0, 775 At the same time, the ratio of fuel to fuel-to-coolant fuel is set to 1: 0.775. When ovdem consumption of solid top.piva on the process of 6.15 t / h, the fuel in the charge okaty

S1071653,

include 6.15: 1,, 45 t / h, and the deficit gas flow of heat carrier from the process — (6.15 0.775): .razor fuel and improve quality

11,, 70 t / h of finished products (metallurgical

The remaining parameters of the process OS-strength 2-4%, drum sample

base changes were changed by 1-2%, the content of class trivialities The invention allowed - 5 mm to 2-4%).

There is no increase in performance with this improvement parameters

zhigchevyh machines by 14-20%, reduce the process of giving: 1st economic

specific heat consumption ka process on the effect. amount to 0.07 million rubles. on

4-7%, partially or completely exclude-1 million tons of pellets.

Claims (1)

: METHOD FOR FIRING IRON PELLETS, including feeding into a batch of coal with a particle size of 0.01-0.10 mm in an amount of 1-20% by weight and blowing Totco-ground solid fuel into a pellet layer in a heat carrier stream in an amount (carbon) of 420 kg / ton of pellets characterized by the fact that, in order to increase the efficiency of the use of solid fuel and improve the quality of finished products, with a volatile content of solid fuel of 1.5-2.5%, the ratio of the consumption of solid fuel in the pellet pellet and in the coolant flow support equal to 1: (1.05-1.40), and with uve ichenii volatile content in the solid fuel with 2.5% for every 5% topli- consumption. VA in the heat carrier flow will be reduced from 1.05 to 0.02-0.07 from the consumption of solid fuel in the pellet charge. I