SU1250579A1 - Gang of high-temperature blast furnace air ovens - Google Patents

Description

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The invention relates to ferrous metallurgy, in particular to air heaters for blast furnaces, and can be used in all sectors of the national economy, where high-temperature heating of gases is required,

The purpose of the invention is to improve reliability, save fuel, reduce metal consumption and improve the environmental situation in the blast furnace.

The drawing shows the unit heaters, a General view.

Air heater waste

The combustion products are collected in the common boar 2 and neither the entrance of the centralized heat exchanger 3, intended for heating the intermediate coolant, enters. The exhaust combustion products (smoke) are removed through chimney 4. In front of the burners 5 of the air heaters 1, the air nozzles 6 and gas 7 each have one heat exchanger 8 and 9, so that a pair of heat exchangers for heating the combustion components belong to one heater, connected in parallel. All heat exchangers are included in the circulation system of the intermediate coolant through the pipelines 10. A pump with a circulating pump.

II (pumps 2, one - working, second - backup cut), the heat transfer fluid passes before entering the smoke heat exchanger 3 through filter 12. Leaving the heat exchanger 3, the heated heat transfer medium is distributed through distribution pipelines 10 through pairs of heat exchangers 8 and 9 for heating the combustion components ,

On the distribution pipes 10, sensors 13 are installed to measure the flow rate of the diverted intermediate heat carrier, as well as valves 14, which can take positions: open 5-100%, fully closed.

If the valves are open by less than 5%, then the heat balance of this amount of liquid will be insufficient to maintain the coolant in a hot state during the winter period.

A 5% open position is provided for heat transfer fluids (e.g. DFS), solidifying at a temp 10

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In the case of cooling (up to -12.3 ° C) during the time during which the corresponding heater is on the blast.

A collecting tank 15 is provided in the circulation system.

When the coolant in the heat exchanger 3 is heated, an increase in its volume is sensed by the expansion vessel 16 connected via a valve 17 to the collector of the blast-furnace gas of the air heater unit.

Expansion vessel 16 also ensures the reliability of the circulation pumps 11, preventing the occurrence of the last cavitation; for the same purpose, R vessel 16 with nitrogen (argon), for example, creates a predetermined pressure. Gaseous decomposition products of the liquid are also collected in the vessel 16. In order to compensate for the leakage of fluid, the system provides boosting pumps 18, which are switched on by a level regulator while the liquid level in the vessel 16 is reduced to the minimum and filled to a predetermined level.

The upper limit of the liquid in the expansion vessel 16 is maintained by means of a bypass transferring excess liquid from the expansion vessel 16 to the collection vessel 15 (heated with water vapor in the case of DFS). Due to this, the capacity of the expansion vessel 16 is taken significantly less than the collection vessel 15 In this case, for the above-mentioned liquids, the volume of the expansion vessel is Vp l, 35, where V is the volume of 40 liquids in the system (at a liquid temperature of 250 ° C, an increase in volume, for example, DFS is 23%). The heat exchangers 8 and 9 of the air heaters 1 are also connected to the emergency drain line.

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On the return pipeline 19 before the circulation pumps 11. connected to the emergency drain line, a separator 20 is installed to separate the uncondensed gases from the liquid. Separator 20 is a cylindrical tank with a diameter that slightly exceeds the diameter of the inlet pipeline (a decrease in the flow rate leads to the release of gas bubbles emerging and their direction to the expansion vessel 16).

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To prevent corrosion of the walls of the circulation system in the event of a decrease in the temperature of the smoke in the common boar, which catches the sensor 21, the measuring device and the controller (not shown), a bypass 22 with a control valve 23 is provided, which by-passes the heat transfer medium through gas and air heat exchangers.

Temperature control under the dome of air heaters 1 is carried out by changing the temperature of heating the combustion components in a pair of heat exchangers 8 and 9, which is achieved by measuring the amount of coolant flowing through pipelines 10 and controlled by valves 14 Е depending on the set temperature under the dome of a specific air heater, since air heaters have various

Editor L.Avramenko Order 4378/21

Compiled by R.Seifulov Tehred O.Gortvay

Corrector

Circulation 552Subscribe

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab, d. D / 5

Production and printing company, Uzhgorod, st. Project, 4

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thermal performance. The temperature under the dome is measured by the standard method (not shown). The adjustment and monitoring of the operation of the system provides for monitoring the flow rates of the sensor 13) and the temperature (sensor 2) of the heat transfer medium before each pair of heat exchangers 8 and 9. 26 on the gas supply. The adjustment of the changed gas supply to the air supply is achieved by a combustion controller acting on the throttle 27. The switching of the heat exchangers by means of valves 1A is included in the reheat circuit of the air heaters.

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Proofreader I. Muska

Claims (2)

1. BLOC OF HIGH-TEMPERATURE BLAST DOMAIN AIR HEATERS, comprising gas and air supply pipes, a system for utilizing combustion products, consisting of a centralized heat exchanger installed in a common hog, an intermediate heat-separator tank, control valves and connecting pipelines, which is characterized by reliability of operation, fuel economy and reduction of metal consumption, individual for each air heater are installed in the nozzles for supplying gas and combustion air mponenta combustion heat exchangers, conduits which are connected in parallel between a loop thereon intermediate coolant. 2. Block pop. 1, characterized in that, in order to improve the environmental situation in the blast furnace shop, the intermediate heat carrier salary tank is connected via a control valve to the blast furnace gas collector. SU., 1250579