Method and device for injecting gases containing oxygen

(42) Date of commencement of the patent: 15. 7.1992 (45) Date of issue: 25.2.1993 (56) Documentation:

(73) Patent owner:

EP-Al-413947 EP-A2-340177 WO 90/07992

RANNER DIETRICH DIPL.ING.

A-5301 EUGEM50RF, SALZBURG (AT).

(54) METHOD AND DEVICE FOR INJECTING OXYGEN-CONTAINING GASES (57) The invention relates to a method for injecting oxygen-containing gases, esp. Air, contaminated, granular or lumpy material, eg in landfills, wherein the oxygen-containing gas intermittently, esp. with a frequency of 1/30 to 1/10 Hz, under high pressure, eg in the range between 2 to 10 bar, injected abruptly (injected) into the contaminated material, the duration of a Einblasevorganges preferably in the millisecond range, and an apparatus for performing this method.

QQ

AT 395 686

MB 0078310

In large municipal waste composting plants, it has been known (EP-A2-340177) to maintain a continuous rotting process in a tunnel-type container of 100 meters in length and 6 × 6 meters in cross-section by means of aeration, venting and humidifying means. The garbage is abandoned unsorted, since the separation of non-rotting garbage can easily be carried out by compost formed by the rotting process. About special, unspecified facilities air is supplied to the garbage under slight pressure.

The known method thus serves the continuous treatment of fresh waste in a closed system.

In contrast, the invention relates to a method for injecting sauastoffhaltiger gases, esp. Air, contaminated, granular or lumpy material, eg. B. in landfills.

Contaminated soils, contaminated sites at industrial sites and abandoned landfill sites pose a threat to man, the environment and the environment. Up to now, these sites have been largely renovated by clearing out, cleaning or relocating to secured locations. These "off-situ" methods are very expensive and correspondingly expensive.

Substantially favorable would be biological "in situ" remediation methods in which the contaminated baize itself is processed as a bioreactor and pollutants are degraded bacterially.

By WO 90/07992 calve a method za biological purification of soils z. B. as a longtime location eina industrial plant contaminated with biodegradable pollutants calf, known. This contaminated soil is dumped and preferably prepared by admixing broken concrete (rubble) to a well-ventilated body. The processed material is piled up on prepared subsoil for regeneration rents between 2 and 3 m in height. The rents are vented during microbiological degradation by venting air duct exhaust because landfill gas is depleted of oxygen to assure uniform ventilation through a network of pipes in the landfill. According to the known method pollutants are mined aerobically unta great effort. The soil must be but ausgekoffert and prepared so that even at drucklosa oxygen supply sufficient oxygen reaches the pollutants It is hiebei to establish a secure landfill area, so that the Aufbaeitung of old landfills is practically impossible because such landfills must not be opened, otherwise foul-smelling substances and toxic gases can enter the environment.

However, EP-A1-0 413 947 discloses a process for the purification of contaminated soils in which, without transport of the soil to the soil surface, the soil structure is loosened progressively by means of a liquid introduced under high pressure, in each case within at least one substantially cylindrical soil body. Apart za loosening of the soil, the liquid serves as a carrier and transport medium for at least one of the respective pollutant in place (in situ) degrading and / or converting active ingredient. The active ingredient can be a chemical agent that reacts with the pollutants to harmless compounds, or a biological nutrient, etc., which allows the removal of pollutants directly in the soil. The oxygen supply necessary for biological measures usually takes place via H₂O2 with the problem of toxicity to bacteria. The known spraying method is not suitable za treatment of old landfills and can be used in grown soils na then when a threat to the groundwater roof the introduced into the soil liquid and the added active ingredient is not possible.

In addition to soil and pollutant-specific problems, it has not been possible to ensure the aaoben conditions necessary for biological processes in the entire contaminated area. Try to pump in hydrogen peroxide (H₂O₂) and nitrate (NO₃) or roof aerobaric air blowing, brought partial success, as large areas of the contaminated soils were cut off from the feed of sauerkraut and therefore could not participate in the biodegradation process. The reason for this is to be seen in the fact that the oxygen carriers penetrate mainly into fractures and roof-ventilated zones of the soils, roofing the onset Rotteprozeß proper ventilation ducts arise densely stored zones of the soil, lack of appropriate pressure, but did not receive oxygen.

Hia remedy is one of the goals of the invention. It is proposed for this purpose that according to the invention, the sauastoffhaltige gas intermittently, esp. With a frequency of 1/30 to 1/10 Hz, under high pressure, for. B. in Baeich between 2 to 10 bar, injected abruptly (contaminated) in the contaminated material ', the Daua an injection preferably located in the millisecond range

In accordance with the procedure according to the invention, in contrast to the previously customary method, the air is not injected continuously into the soil or landfill with only slight overpressure (0.1-0.3 bar), but instead pulsates intermittently and under considerably higher pressures (2 -10 bar), so to speak. However, the total amount of air remains the same compared to the method previously used, but the impulse is so large at the expiring in the range of milliseconds blowing that, without prejudice to any existing gaps and porous Baeichen, the air easily penetrates into densely supported zones of contaminated soil Thus aerobic conditions can be achieved throughout the contaminated area.

-2AT395686B

As the oxygen-containing gas, it is particularly useful to use oxygen-enriched air. The displaced by the sudden supply of the oxygen-containing gas from the contaminated material gases are extracted locally

Are used for gas supply lances, can the explosive supply of the gas be achieved thereby 5 in that it operates on a device, characterized in that, according to the invention, the lance is closable at one end by the end face of a piston, which can be moved back and forth against the pressure of a spring in a cylinder, is slidably mounted in particular, the one about, preferably the piston passing through opening, communicating with the interior of an air chamber, wherein the piston head is provided in the region opposite the opening of the lance with bores which lead into a space located in the interior of the piston, the one about, By a spring loaded valve plate closable opening with the displacement of the cylinder of the piston is connectable. This device makes it possible to suddenly connect the interior of the lance with the pressure chamber of the air chamber for only a short time and thereby abruptly remove the oxygen-containing gas from the air chamber and inject it via the lance into the contaminated soil.

In a further embodiment of the device according to the invention can be provided that the lance in the

Windkessel is set, wherein the blow-off perforations end piece of the lance outside the

Windkessel is arranged. Hiebei each lance is directly supplied by a wind boiler associated with her, so that each lance is a sufficient storage capacity of oxygen-containing gas available.

The load on the valve plate can be changed in a simple manner, if arranged in a further embodiment of the invention, the closable by the valve plate opening in a, inserted into the piston, preferably in the axial direction of the piston sealing ring is arranged Thus, it is possible, the pressure at the reaching of which opens the valve plate to regulate. This adjustment can be easily made when the sealing ring is screwed into the piston. To improve the sudden gas supply to the contaminated soil, it is advantageous if, in a particular embodiment of the invention, the piston projects laterally beyond the lance. As a result, a large attack surface is available for the pressure of the gas acting in the direction of the opening movement of the piston, whereby the force acting in the closing direction of the spring loading the piston is rapidly overcome and the piston moves into the open position

A quick opening of the piston closing the lance is beneficial, if the total cross section of the holes arranged in the bottom of the piston, which connect the interior of the lance with the space in the piston, is greater than the cross-section of the opening, via which the displacement in the cylinder is connected to the air chamber To move the piston without wear in the cylinder, it is appropriate if in a particular embodiment of the invention, the piston is connected to the cylinder via a rolling diaphragm

Targeted removal of the displaced gases is achievable when provided with lances connected to a mammalian pump, optionally with the mammal pump connected on the outlet side to a filter. If a filter is provided, then any pollutant emissions can be further reduced.

DieErfindungwirdnachstehendanhandderZeichnungbeispielsweisenähererläuterLEszeigen.Fig. 1 partly in section, a device suitable for carrying out the method according to the invention, 2, in relation to FIG. 1 larger scale, a detail from FIG. 1 in an axial section, Fig. 3 the detail of FIG. 2 in a relation to FIG. 2 changed position, Fig. 4 schematically a plant for the aeration of waste using the method according to the invention and in Figs. 1 3, and FIG. 5 one opposite the Fig. 2 and 3 modified variant.

In the drawing, (1) denotes a blast furnace with compressed air connection (2). From the blast furnace (1), a lance (3) is supplied with compressed air or other oxygen-containing gas. The lance (3) is equipped with a perforated end piece (4). Through the perforations of this end piece, the oxygen-containing gas is discharged to the outside. The lance (3) has a tightly passed through the Windkesselwand pipe section (5).

The pipe section (5) is connected to the end piece (4) outside the air chamber (1) via a screw connection (35). The pipe section (5) and thus the lance (3) is sealed by a piston (6) which rests on the annular end surface (7) of the pipe (5) which is designed as a sealing surface. The piston (6) is part of a quick exhaust valve (8 ), which, as will be described below, is arranged so that the piston (6) abruptly springs back upon reaching an adjustable pressure in the air chamber (1) and the entire

Passage cross-section of the pipe section (5) releases, so that the oxygen-containing, in the air chamber (1) stored under pressure gas explosively escapes through the perforated end of the lance (3) Once the pressure in the air chamber has dropped, closes the piston (6) under the pressure of a spring acting in the closing direction (9) is, again the opening of the tube (5) until the set pressure in the air chamber (1) is reached again and the next emptying takes place explosively

The quick exhaust valve (8) in a preferred embodiment is shown in Fig. 2 in the "closed" position, and Fig. 3 illustrates the "open" position.

The piston (6) is reciprocable in a cylinder (10) concentric with the pipe section (5) of the lance

-3AT395686B (3) embedded in the tank bottom (11) and welded to it The piston (6), the end face (7) of the tube (5), the spring (9) and the cylinder (10) form the actual quick exhaust valve ( 8th). The piston (6), as shown in FIGS. 2 and 3 in more detail, slide in the cylinder (10), however, the movement of the piston (6) can also be carried out verschlußfiei, if - as shown in FIG. 5 - the piston ( 6) via a rolling diaphragm (41) with the

Cylinder (10) is connected to the piston (6) is a plate valve (12) for controlling the movement of the piston (6) is inserted. The plate valve (12) consists of a by means of thread (22) in the piston (6) axially adjustable sealing ring (13), a valve plate (14) and a spring (15), which endeavors, the valve plate (14) in a «position in that it closes a central passage opening (17) of the sealing ring (13).

If the air chamber is filled with the pressurized, acid-containing gas, eg. B. Filled with air, the piston (6) of the quick exhaust valve (8) is in the initial position according to FIG. Second By way of one (possibly several) openings (16) passing through the piston (6), the gas also passes into the displacement space (34) located above the piston (6), in which the spring (9) is located. Since the plate valve (12) is also closed and there is only a slight overpressure of 0.1-0.3 bar in the tube piece (5) and thus in the lance (3), the piston (6) will be fixed on the stop face (7 ) of the tube (5) until the pressure in the stroke chamber (34) has increased to such an extent that the valve plate (14) of the plate valve (12) opens, whereby the pressure in the space above the piston (6) is vented. This is possible in spite of the opening (16), since the opening cross section of the plate valve is many times larger than that of the opening (16). In addition, at the moment of opening not only the valve plate (14) in a the cross-section d 'opening (17) of the sealing ring (13) corresponding pressure is applied, but the much larger area of ​​the entire valve plate (14). As a result, the plate valve (12) remains open despite pressure drop in the displacement (34) (Fig. 3) and the gas can over the bores (18) (approx. 6 Stk) escape from the space (33) in the piston (6) in the pipe section (5). The piston (6) is thereby relieved of pressure on the side of its spring (9) and driven into the cylinder (10) by the air pressure acting on the annular surface (19) (FIG. 3), whereby an annular opening (20) is formed whose area is greater than the cross-sectional area of ​​the pipe section (5) or the lance (3). The gas under pressure in the air chamber (1) can therefore explode over the perforation (4) of the lance (3) into the

Escape soil or landfill. The annular surface (19) is created by projecting the piston (6) laterally with respect to the end face of the tube (5). To control the blow-off pressure, the sealing ring (13) of the plate valve (12) is axially displaceable on the piston (6) by means of the thread (22), whereby the spring (21) loading the valve plate (14) can be more or less biased. This changes the

Opening pressure of the plate valve (12), which can be adjusted between approx. 2 and 10 bar. The number of shots which can be discharged per minute therefore depends on the amount of air supplied per unit time and on the set opening pressure of the plate valve (12). It is usually between 2 and 6 shots per min.

4 shows the flow diagram of a ventilation system equipped with lances (3) according to the invention for the aerobization of a household waste landfill. The waste layer to be disposed of in the drawing (36) covers the topsoil (37) and is covered at the top by a soil layer (38) on which humus (39) is mounted.

The lances (3) with their wind boilers (1) are connected via a pipe system (23) to a compressed air compressor (25), which supplies the lances (3) with compressed air via a buffer wind tank (24). To vote the

Compressed air supply pressure reducing valves (26) the lances (3) are connected upstream.

If oxygen enrichment is required, O₂ supplied from an O2 system (40) of a mixing chamber (28) and the compressed air dosed mixed.

The landfill gas, which can only be removed to a slight extent by the earth layer (38) and the humus coating (39), was swept by the suction lance! (27), a line network (30) and a mammalian pump (29) aspirated and fed to a biofilter (31).

In Fig. 4 is caused by the explosive supply of the oxygen-containing gas spherical

Shockwave (32) drawn, which covers the entire landfill area around the respective lance (3), thereby ensuring the supply of oxygen throughout the garbage body.