SU772995A1 - Damp method of cement clinker annealing - Google Patents

Description

one

The invention relates to methods for firing clinker, predominantly white cement in short rotary kilns of the wet production method, but can also be used in the production of portland cement clinker.

The known method of burning cement clinker in rotary kilns of the wet method, including drying, heating, e-decarbonization and sintering of the raw mix.

The disadvantage of this method is that in short rotary kilns of the wet method (especially kilns 15 for firing white cement clinker) the specific heat consumption reaches 20003000 kcal / kg clinker. Such a high heat consumption is attributed to large losses in the surrounding environment with 20 moving gae, amn, clinker, radiation from the furnace body, and with ablation dust. Material ablation is great due to insufficient filtering ability of short chain curtains in the furnace and high speed of furnace gases. The temperature of exhaust gases in short rotary kilns varies from 320 to depending on the length of the furnace and the chain curtain, the sludge moisture content and the organization of 30

fuel combustion. The performance of short rotary kilns is low.

The closest to the technical essence and the achieved effect to the proposed is the SPS method of burning cement clinker in rotary kilns of the wet method, including drying and heating the raw mix, selection of dry material through the openings In the side surface of the kiln, heating and decarbonization of the selected material outside the kiln to remote the preheater and calciner with additional combustion in them of fuel with the subsequent introduction of the decarbonated material into the furnace for sintering 2.

Despite the efficiency of the known method, its practical implementation is difficult to implement, which is associated with the introduction of decarbonated material with a temperature of 950-1250 s from the stationary calciner into the rotary kiln through the hatches in the side surface of the furnace.

It is characterized by the limitation of furnace capacity due to the high velocities of furnace gases, to which calcinator flue gases are added due to the large material carried out of the furnace by high fuel consumption due to heat losses from the flue gases, whose temperature does not decrease due to installations of this type of calciner, as well as due to a significant increase in the volume of gases supplied additionally from the calciner, and significant inflow of ambient air through four annular units in the area of unloading and loading windows rotary kiln. In addition, fuel consumption increases due to losses with the loss of large amounts of material having a temperature of exhaust gases. The lining in the sintering and calcining zone is short-lived due to unreasonably high temperatures in these zones and the curtains in the drying zone and the heat exchanger in the heating zone are also short-lived due to the high gas temperatures at the entrance to these zones and limiting the amount of material being processed through zones limited by the thermal capacity of the sintering zone. The resulting clinker is of low quality due to the limited operation of the furnace on sludge with a high saturation factor, on which the quality depends on in large sepene. The residence time of the material in the known calciner is small, the particles of dry material discharged from the furnace into the calciner are large in size in half of their quantity and, therefore, must be processed for a long time. Therefore, the degree of decarbonization of the material, characterizing the K1Sch of the calciner, is low, which limits the ability to process hard raw materials (i.e., raw materials with a high saturation coefficient. The purpose of the invention is to reduce its own fuel consumption and improve the performance of the furnace. Wet The method of burning cement clinker in a rotary kiln, including drying the raw cement slurry, selecting the dried slurry from the kiln, followed by introducing the decarbated product into the kiln for sintering The extraction of a fraction of 0.05–5 mm in the amount of 5–35% by weight of the dried sludge, and the introduction of a decarbonated product with a temperature of 650950® C, is carried out through the hot end of the furnace by blowing in with compressed air. , for example, white cement clinker, raw spam was prepared with raw yen (by comparison with traditional roasting in known kilns) saturation coefficient (, 91 0, 95). Prepared isham is fed to the loading part of a rotary kiln equipped with a chain curtain of increased line, providing complete drying of the sludge, which is supplied in quantity, is 5-35% higher than the amount of material passing through the heating and decarbonization. The increased length of the chain curtain, the increased amount of material placed in the furnace, drastically reduces the temperature of the flue gases, which in short furnaces can be at a level of 180-280 C. The volume of gases decreases, which leads to a decrease in the corrosion rate of the latter and a decrease in the removal of the material. The temperature of the entrained material also decreases, which leads to a reduction in heat loss. The increased length of the chain curtain provides better filtration of furnace gases, which reduces the dust removal from the furnace. In the chain curtain, dried material in the amount of 5-35% of the total dry material prepared in the kiln, with a temperature of 110130 ° C, is discharged through holes in the side surface of the furnace shell. Special devices are installed in the openings for unloading a part of the material to ensure that fractions with a diameter of 0.05 to 5 mm are used in the required quantity from the entire mass of dry material. Fractions up to 0.05 mm of air flow, inevitably penetrating through seals installed on the furnace at the place of unloading, return to the furnace, where they are caught by the chain curtain, enlarged and re-fed to the area of the discharge openings. Fractions from 0.05 to 5 mm, isolated from the furnace, are driven by a pneumatic screw pump into a collecting bin, and from there, through a weighing feeder, are fed to a dispersed heater installed in the immediate vicinity of the hot end of the furnace (at the furnace head). Into the heater, exhaust gases from the forcalcinator installed under the heater, with the discharge heat of the forcalcinator directed into the furnace head. The waste gases of the forcalciner preheat the material to 600BOOCI B depending on the residence time of the material in the preheater, the dispersion of the material and the temperature of the gases leaving the calciner. The selected range of dispersion of the material ensures the operation of such a forkzhatsinator. The degree of decarbonization in such a precalcinator is 85-90%. The gaseous fuel is supplied to the burner devices of the forcalcinator in an amount necessary for decarbro

Claims (1)

Claim Wet method of firing cement clinker in a rotary kiln, including drying cement raw slurry, taking dried slurry from the kiln and decarbonizing it outside the kiln, followed by introducing the decarbonized product into the sintering furnace, characterized in that, in order to reduce specific fuel consumption, to increase the furnace productivity, the dried sludge of fractions of 0.05-5 mm in the amount of 5-35% of the weight of the dried sludge is selected, and the decarbonized product with a temperature of 650-95СРС is introduced through the hot end of the furnace by blowing it compressed air.