DE3335045A1 - METHOD AND DEVICE FOR REDUCING THE PRESSURE IN THE GAUGE BUNKERS OF A BLAST FURNACE AT NEAR ATMOSPHERIC PRESSURE WITH SIMULTANEOUS RECOVERY OF THE GAS OIL - Google Patents

Abstract

1. A method for reducing the pressure in blast furnace charge hoppers to nearly atmospheric pressure with residual pressure relief by way of silencers into the atmosphere and simultaneous top gas recovery, characterised in that the quantity of relieved gas is intermediately stored in a float tank (7) and is cleaned of dust therein.

Description

1 RG, Si / Pi. - 2603 09/26/1983

10 applicants:

M.A.N. MASCHINENFABRIK AUGSBURG-NÜRNBERG Aktiengesellschaft

15 4200 Oberhausen

AKR: 10 27 20

"Method and device for lowering the pressure in the top bunker of a blast furnace 25 almost atmospheric pressure with simultaneous recovery of the top gas "

The invention relates to a method for lowering the pressure in the top bunkers of blast furnaces to almost atmospheric pressure with residual relaxation via silencers into the atmosphere with simultaneous recovery of the furnace gas.

Modern blast furnaces work with gas pressures of 1.5 2.5 bar overpressure at the top. The smuggling of the Möllerstoff happens via gas-tight chambers, the so-called gout bunkers. After filling in the filler substances in the top bunker the gas pressure in these must be increased to the value of the gas pressure in the furnace before by opening the lower locking mechanisms, the filler substances can be poured into the furnace. After finished The filling process is usually closed again. The lower locking mechanisms and the gas pressure in the gout bunkers reduced to atmospheric pressure by relaxing in the atmosphere. Through this Not only does the calorific value of the top gas are lost, but considerable dust and noise pollution also arise.

Various inventors have recently endeavored to develop methods and devices that In addition to the recovery of this top gas, also keep the dust and noise development within limits.

In DE-PS 30 26 019 a method and an apparatus are described in which the expansion of the top gas from the top bunker in a first process step takes place automatically due to the prevailing pressure. In a second process step then the remaining amount of gas with the help of an ejector sucked off and fed into the clean gas network. The pressure in the gout can bunker up to atmospheric pressure be lowered. i

The disadvantage of this method is that in the first Process step relaxed gas is only roughly pre-cleaned, so that its dust content increases that of the clean gas. The same also applies to the second process step, which is only made possible by the fact that to operate the Ejector clean gas with a high pressure level between the first gas cleaner and the gas pressure control valve Available. This constellation does not exist in modern gas cleaning systems (e.g. type Bischoff).

In addition, the one proposed in accordance with DE-PS 30 26 019 is The device is very complex in terms of lines and fittings and also requires switching From the first to the second process step, complex measurement and control technology.

The system also works with an ejector USSR copyright certificate No. 761 567 from 1977. Here, too, the relaxation takes place in two sub-steps and over two separate pipe systems. First of all, the pressure in the furnace bunker is controlled by a sloping pipe that for the purpose of gas cleaning with a water injection equipped, dismantled. After the clean gas network pressure has been reached in the furnace bunker, the second The pipeline system switched, which also consists of the inclined line with water injection, but is also connected to a vacuum tank. This vacuum tank is continuous Operation of a steam jet ejector at a pressure brought below atmospheric pressure and thus enables the vessel pressures and sizes to be suitably matched Reduction of the pressure in the furnace bunkers to atmospheric pressure. Advantageous compared to DE-PS 30 26 019 is here that extensive cleaning of the gas from the top bunkers is planned. On the other hand, it is

° disadvantageous that the steam to operate the ejector in the

j clean gas arrives and its calorific value is reduced. To be considered is also the cost of that vapor. Finally, this facility is also from the pipelines, the fittings and the measurement and control technology.

A method and an apparatus are also known become, in which the gas to be recovered from the gout bunkers in a U-shaped, to the atmosphere to the open buffer. On the way there, the gas is cleaned by injecting water. To At the end of the expansion process, the gas stored in the U-container is brought to the pressure of the clean gas network and fed to it. The advantage of this embodiment is that the pressure reduction without further mechanical Facilities is done down to atmospheric pressure. The disadvantage, however, is that this is due to the free Form flammable gas / air mixtures in contact with the atmosphere can, and that the gas must be brought back to the clean gas network pressure.

The object of the present invention is to overcome the disadvantages of the methods and devices described above to avoid and an uncomplicated, operationally reliable system for the recovery of the gases from the furnace bunkers to strive for.

This object is achieved in that the relaxed amount of gas from the top bunkers in a floating tank cached and cleaned of dust in this will. A device for carrying out this method is the subject of the subclaims.

The weight load on the floating tank is set so that that there is a pressure inside that is slightly above the pressure in the clean gas network. The cleaning the relaxed gases can flow through both in the pipeline system in front of the floating tank and in this itself Spraying of water done. The separated dust is in the form of a sludge on the bottom part of the floating tank deposited. The swimming tank is monitored through a simple level control. This ensures that the delivery of gas into the clean gas network is interrupted when the floating tank is at its minimum level. On the other hand, is he at its maximum level, the further gas supply to the pool is interrupted and for relaxation Any remaining gas discharged into the atmosphere in a conventional manner via a silencer.

The advantages of the described invention are as follows:
20th

a) simple piping, few fittings, simple measurement and control technology;

b) Relaxation almost to atmospheric pressure possible, Dispensing with a complicated set-up

for the residual relaxation (The residual relaxation follows conventionally via silencer);

c) The gas can be cleaned in front of or in the floating tank; because only very low gas velocities in the gas container occur during emptying, the latter option is particularly favorable;

d) no formation of ignitable gas / air mixtures, none

^OJ post compression required.

] The invention is explained in more detail using an exemplary embodiment and with reference to the drawing.

The reference numbers in the drawing have the following meanings;

1 gout bunker.

2 gout bunkers

1a p-measurement in the top bunker 1 2a p-measurement in the top bunker 2

3 Expansion line between the top bunker and the floating tank

4-6 valves in the expansion line

7 floating tanks

8 floating roof

-c · 9 bottom part of the floating tank

10 guide rollers for floating roof

11 Maximum limit switch on the float tank

12 minimum size switches on the floating tank

13 Washing line in the floating tank 2Q 14 Pump

15 washing nozzles

16 Sludge outlet on the bottom part of the floating tank

, 17 Connection line floating tank to. Clean gas

18 Valve in the connection line

19 gas scrubbers

20 dust bag

20a raw gas from the blast furnace

21 Filling line from the gas scrubber to the top bunkers 21a, b Valves in the filling line 21

22 Valve in the filling line

23 Adding nitrogen to the filling line

24 Blow-off line from the expansion line to the atmosphere

■ 25 water levels in the float tank

The direction of flow in the lines is indicated by arrows.

- 7 -

The furnace gas expansion takes place as follows:

Valves 21a and 21b in the filling line 21 to the top bunkers 1 and 2 are closed. The valves 4 or 5 and 6 in the expansion line 3 behind the top bunkers are opened. The floating roof 8 of the swimming pool 7 swims upwards in the guide rollers 10.

The termination of the relaxation is detected in the bunkers gout 1 or 2 or on timing either the A p-measurements 1a or 2a.

After the end of the relaxation, the valve 6 closes in the Relaxation line 3. The valve in the blowdown line 24 to the atmosphere opens for residual relaxation. At the same time, the valve 18 opens in the connection line 17 from the swimming tank to the clean gas network, whereby Gas is fed into the clean gas network.

The valve 18 closes as soon as the floating roof 8 of the floating container 7 has reached its minimum position and the minimum limit switch 12 gives a signal or a next relaxation process is initiated.

To an overfilling of the swimming tank 7, which could occur if many relaxation processes in quick succession need to be driven to avoid reaching the maximum position of the floating roof the maximum limit switch 11 reported. In this case closes the valve 6 in the expansion line 3 and opens the valve in the vent line 24 to atmosphere.

In the exemplary embodiment, the expanded gases are cleaned in the floating tank 7. To this end

is via the pipeline 13 by means of a pump 14

Water using the spray nozzles 15, which are located below the Floating roofs 8 are arranged, sprayed. The separated dust collects on the bottom part 9 of the Floating tank and is withdrawn via the sludge outlet 16.

Instead of cleaning the gases in the floating tank, the gases can also be cleaned as an alternative or in addition in the pipe system in front of the floating tank, i.e. in the stress relief pipe.

While the expansion line 3 and the connecting line floating tank to the clean gas network in the embodiment open through the open bottom of the floating roof 8 into the floating tank 7 and above end of the water level 25, these supply and discharge lines can alternatively (not shown) join from above through the floating roof. In this case, the feed and discharge are for the implementation. Lines sliding seals arranged on the floating roof.

Claims (8)

Patent claims: 1. Process for lowering the pressure in the top bunkers of blast furnaces to almost atmospheric pressure with residual relaxation via silencers into the atmosphere with simultaneous recovery of the top gas,
characterized, that the relaxed amount of gas is temporarily stored in a floating tank (7) and in this of Dust is cleaned. 2. Device for performing the method according to claim 1, characterized, that a floating container (7) is provided for gas expansion and gas cleaning, and weight as well Cross-section of the floating roof (8) of the floating container (7) are dimensioned so that the gas pressure in the floating tank (7) is slightly above the pressure in the clean gas network. 3. Device according to claim 2,
characterized, that the volume of the floating container (7) to accommodate the relaxed amount of gas to at least two Goutbunker relaxations is designed. 4. Device according to claims 2 and 3, characterized in that that the position of the floating roof (8) is monitored by limit switches (11, 12). - A2 - ] 5. Device according to claims 2 to 4, characterized, that in the floating tank (7) and / or in the expansion line (3) to the floating tank (7) the relaxed gas is cleaned by water injection: will. 6. Apparatus according to claim 5, characterized, IQ that the separated dust from the bottom part (9) of the Floating tank (7) is withdrawn via sludge pumps. • 7. Device according to at least one of claims 2 to 5, characterized, that the expansion line (3) and the connecting line (17) to the clean gas network through the open The bottom of the floating roof (8) open into the floating tank (7) and above the water level (25) ends. 8. Device according to at least one of claims to 6, characterized, that when the expansion line (3) is fed in and the connecting line (17) is discharged from up through the floating roof (8) into the floating tank (7) for the passage of these lines Sliding seals are provided.