SU1089135A1 - Method for drying and heating-up blast furnace air heaters - Google Patents

Abstract

METHOD FOR DRYING AND HEATING OF DOMAIN AIR HEATERS, including the sequential supply of cold blow, hot blow and fuel, so that, with the purpose of increasing the durability of air heaters and increasing the efficiency of heating, a cold blow pass through the air heater for a time ensuring that the temperature under the dome reaches “0.7–0.9 temperature of cold blowing, hot blast from the beginning of the second stage is served continuously. As the time when the temperature under the dome reaches 400-500 C - cyclically, with a frequency of the cycle corresponding to the time of temperature rise under the dome by 70-100. This is tripping the air heater S from blowing at the end of each cycle for a time ensuring that the pressure in the air heater reaches 0.05-0.075 ati.

Description

thirty

: o: l The invention relates to black letion, in particular, to methods of heating and heating of hot blast stoves after their construction and repair, and can be used in the power industry. There is a method of drying the lining and nozzles of blast furnaces first with wood and then with gaseous fuel (natural, blast furnace or coke gases) lj. The disadvantage of this method is the difficulty of adjusting the drying parameters when using firewood, and, consequently, the accuracy of maintaining the specified heating schedule, the presence of moisture and ash in the firewood, the use of scarce natural and coke oven gases, is insufficient. The closest to the present invention is the method of drying and heating the blast stoves, which includes the sequential supply of cold-blown, hot-blown and fuel {21. The disadvantages of this method are the use of blowing for drying, in most cases enriched with oxygen, which, after passing through the stove, is not used and released into the atmosphere, the continuous flow of the blow through the stove. The steam formed during the drying process, due to the high pressure (2.5-3.5 atm) inside the heater air rushes to the iberipheric masonry layers and the casing, is condensed, and the water that forms with the lining, by deteriorating their physical and mechanical properties, in the initial drying period of the stove the used cold blast is fed into the furnace, but with it a significant amount of moisture gets, resulting from drying of the masonry, which worsens the blast furnace smelting process and leads to coke overrun. During this period, there may also be a discrepancy in the required flow rates, firstly, the furnace requires a certain amount of air to see, secondly, such an amount of blowing must be supplied that would ensure compliance with the required drying schedule. These costs MAY NOT be numerically equal. The purpose of the invention is to increase the durability of the hearing aids and increase the efficiency of the nagoi path. The goal is realized so that according to the method of drying and pa-; The heating of the replacement of the viewer. including the sequential supply of cold blowing, hot blowing and fuel, the cold blowing is passed through the air heater for a time ensuring that the temperature under the dome is 0.7-0.9 cold blowing, the hot blowing from the beginning of the second stage is served continuously, and since reaching temperature below. dome 400-500 ° C - cyclically, with a duration of cycles corresponding to the time of temperature under the bottom of the UO-100®С floor and with the heater disconnected from blowing at the end of each cycle for a time ensuring that the pressure in the heater is 0.05-0.075 ati. A breakdown of the drying and heating period into three stages is necessary to ensure a smooth and uniform process. In the first period, drying is carried out with cold blasting in order to gradually and uniformly warm up the masonry and the nozzle. When the temperature under the dome reaches 0.7-0.9 the temperature of the cold blowing, the heater is switched to drying with hot blowing. The temperature of the cold blowing depends on its pressure and in most cases is 80-200 C. At a temperature of 120 ° C, the average temperature under the dome is cold blowing is 96 ° C (see table). When the temperature under the dome is less than 0.7 of the telescope blowing system (84 ° C), it is not advisable to switch the air heater to hot blow-drying, since the cold blowing still has the energy potential for drying and its efficiency has not yet been fully utilized. When the temperature under the dome reaches 0.9, the temperature of the cold blast (108 C), it is not advisable to keep the heater on the cold blast, as to further raise the temperature under the dome to the temperature of the cold blow, a considerable time interval is needed which does not correspond to the drying and heating schedule. The table gives the parameters of drying and heating of air heaters.

20-84 84-400

400 470 540 610 680 750

From fuel to main

750 burner. After transferring the air heater to hot blast drying, the process goes on continuously until the temperature reaches 400-500 0.3 under the dome, then its cyclic part begins to periodically separate the air heater from the air blower and remove it until the air heater reaches 0.05-0.075 ati. Such an operation is carried out through a 70-100 ° C rise in temperature under the floor. Periodic office may- :. through a 70-100 temperature rise under the dome from a hot blow and its removal from the workspace, first of all, there is an increased pressure in the air heater, a hot pressure blow - 2.53, 5 MPa, which causes

20-108

0-96 108-500 6-450

500

450 600 535 700 620 800 705 900 790 1000 875

875 1000

The commissioning of the air heater from the central areas of the masonry to the peripheral layers and its accumulation in the outer, peripheral zone is put into operation. The hot blast passing through the stove carries moisture from the outer layers of the masonry, which is located in the outer masonry adjacent to the casing, does not remove with the blast. By separating the stove from a hot blow, lowering its pressure and removing it from the stove, the peripheral moisture is able to move into the inner layers of the masonry and leave the working space after the blast-out. The filling and removal of the blowing from the air heater is carried out every 70-100 ° C as the temperature rises under the dome because this interval ensures the accumulation of the optimal amount of moisture that the hot blast can remove from the working space. If the interval limit is lower than 70 ° C, then the amount of moisture generated will be small and it is impractical to remove it from the air heater. If the interval limit is increased higher, then the resulting amount of moisture will condense, which will lead to deterioration of the properties of refractory materials. Removing the blow from the air heater until the pressure in it reaches 0.05-4), 075 MPa is due to the fact that with a decrease in pressure of less than 0.05 MPa, the schedule of drying and heating is extended, and with increasing pressure more than 0.075 MPa from the air heater All moisture will not be removed. The drawing shows a blast stove, vertical section. The blast stove consists of a combustion chamber 1, a nozzle 2, a sub-nozzle 3, smoke nozzles 4 on which valves 5 are installed, a fitting 6 is hot blown with a shut-off gate 7, a gas burner fitting 8 with a gate 9, a cold blow fitting 1 with a gate 11 The fittings 8 and 10 of the burner and the cold blow, respectively, to gates 9 and 11 are connected to the air ducts 12 and 13 with a desiccant 14, which in turn is connected by the air duct 15 to the common pipe for the combustion unit of the air heaters and the bypass pipe 16. tional lines 12 and 13 and the bypass pipe 16 are mounted valves 17-19. In the dome of the air heater, the sensor 20 is mounted with a sensor 21 for measuring temperatures. A 10 cool bore fitting to gate 11 is equipped with a sensor 22 for measurement. The air heater is equipped with air ducts 12 and 13, which. Connect the fittings 10 and 8 of the cold blowing and gas burners, respectively, to the gates 9 and 11 with the desiccant 14 blowing and the common air line of the combustion air heaters. On the connecting pipes 12 and 13, valves 17 and 18 are installed. The air heaters are dried and heated as follows. In the first period: the cold-blast flows through the cold-blast nozzle 10, the sub-nozzle device 3, the nozzle 2, the dome space 20, the combustion chamber 1, the main burner fitting 8, the connecting air duct and the passage through the dryer 14 and the pipeline 15 into the general air pipeline combustion heaters block. When this gate 7 hot blowing gas burner 9 and valves 18, 19 and 5 on the connecting pipe 13, the bypass pipe 16 and the flue nozzles 4 are closed, and the gate 11 cold blow and valve 17 on the connecting pipe 12 otkrlgty. In the second period, at medium temperatures under the dome 96-450 ° C, the heater is heated with hot blast, which from the direct air duct enters the choke hot blow 6, chamber 1 burns the dome space 20, nozzle 2, sub-nozzle 3, nozzle 10 cold blowing, connecting pipe 13 and, the passage through the dryer 14 and pipe 15, gets into the common combustion air duct of the air heaters block. At the same time, the gates 9 and 11 of the burner and cold blow, respectively, as well as valves 17, 19 and 5 on the connecting pipe m the conduit 12, bypass conduit 16 and nozzles 4 the flue closed and the gate 7 and hot blast valve in the connecting conduit 18 are opened. The speed of temperature rise under the dome regulates-.k (with by gradually opening the butterfly valve 18.). When the average temperature under the dome reaches 450 C, it is necessary to cyclically feed the mountains, blowing every 70-100 ° C. installed in the dome 20, the temperature under the dome is measured and, when it reaches 450c, the gate 7 is closed to blow hot. When the pressure in the working space of the air heater is reduced, the steam, 1CiS in the peripheral layers of the building, is blown away. zmer by pressure in the working space and stoves with a decrease in pressure to p atm close the valve in the connecting conduit 18, the release of blowing, comprising i moisture from stoves fed again the hot blast.

Claims (1)

METHOD OF DRYING AND HEATING of each cycle for a while, providing the DOMAIN AIR HEATERS, including the achievement of pressure in the air-conditioning sequential feed of 0.05-0.075 ati. / ’