Method and device for injecting gases containing oxygen.

p0001In Großkompostieranlagen for municipal waste, there has been known (EP-A2-340177), maintain continuous rotting process into a tunnel-like container of 100 m length and a cross section of 6 x 6 m, by aeration, ventilation and humidification. Garbage is doing unsorted abandoned because the separation of non-putrescible waste components can be easily carried out by created by the rotting process compost. Using special, not further described means is supplied under slight positive pressure air to the waste.

p0002The known method is therefore by the continuous treatment of fresh waste in a closed system.

p0003In contrast, the invention relates to a method for injecting oxygen-containing gases, in particular air, to the contaminated, granular or lumpy material, for example in landfill sites.

p0004Contaminated soils, environmental liabilities at industrial sites and abandoned garbage dumps represent risks for humans, animals and the environment. The restoration of these sites was carried bisnun predominantly through clearing, cleaning or renewed depositing at secure locations. This "off situ" process are very complex and expensive.

p0005Much more favorable to biological would provide remediation methods "in situ", in which the contaminated area even worked as a bioreactor and pollutants are decomposed by bacteria.

p0006Through the document WO 90/07992 a process for biological treatment of soils has been known, for example, have been contaminated as a longtime location of an industrial plant with biodegradable pollutants. Here, the contaminated soil is excavated and preferably by mixing crushed concrete (construction waste) processed into a good durchlüftbaren body. The recycled material is coated on a prepared subsoil regeneration clamps 2-3 m height. The clamps are provided during the microbiological degradation of the contaminants either by blowing air or by suction of the dump gas with oxygen, said even aeration should be ensured by a network of pipes in the landfill body. According to the known method pollutants are degraded aerobically at great expense. However, the soil must thereby be excavated and presented in a way that gets enough oxygen to the pollutants even in unpressurized oxygenation. It is hiebei to build a secure landfill area, so that the treatment of old landfills is practically impossible, because such landfills may not be opened, otherwise malodorous substances and toxic gases could escape into the environment.

p0007By EP-A1 0,413,947 a method for the purification of pollutant-containing soils has been known in which a loosening of the soil structure by means of an introduced liquid under high pressure is carried out without a transport of the ground progressively to the bottom surface, respectively within at least a substantially cylindrical body of soil. Except for the loosening of the soil, the liquid serves as a carrier and transport medium for at least one each pollutant on the spot (in situ) depleting and / or converting agent. The agent may be a chemical agent that reacts with the pollutants into harmless compounds, or a biological nutrient etc., which enables the elimination of pollutants directly into the ground. The necessary measures for biological oxygen supply occurs most commonly via H₂O₂ with the problem of toxicity to bacteria. The known spraying is not suitable for the treatment of old landfills and can only be used in natural soil, when a risk of groundwater contamination by introduced into the bottom liquid and the added agent is not possible.

p0008In addition to soil and pollution-specific problems it has not been possible to secure the necessary biological processes aerobic conditions in the entire contaminated area. Attempts by pumping hydrogen peroxide (H₂O₂) and nitrate (NO₃) or manufacture by blowing air aerobic conditions, brought only partially successful, because large areas of contaminated soil remained cut off from the supply of oxygen and therefore the biodegradation process could not attend. The reason for this is the fact that the oxygen carrier penetrate mainly in ravines and durchlüftbare zones of soils, which are caused by the onset of rotting process veritable ventilation channels, densely packed areas of soils, lack of appropriate pressure, but did not receive oxygen.

p0009Here remedy, is one of the objectives of the invention. Proposed, will be a, that according to the invention the oxygen-containing gas intermittently, esp. At a frequency of 1/30 to 1/10 Hz, under high pressure, for example, is in the range between 2 to 10 bar, suddenly blown into the contaminated material (shot) the duration of a Einblasevorganges preferably in the millisecond range.

p0010According to the procedure of the invention is in contrast to the usual method, the air is not continuously and with only a slight positive pressure (0.1 - 0.3 bar) is injected into the soil or landfill, but intermittently pulsating and under much higher pressures (2 - 10 bar) quasi injected. However, the total amount of air will remain over the method used to date the same, but the pulse is in the in the range running from milliseconds blowing operation so great that, without prejudice to any existing fractures and porous areas, the air easily penetrates even in densely packed areas of the contaminated soil. This aerobic conditions can be achieved in the entire contaminated area.

p0011The oxygen-containing gas, it is particularly advantageous to use oxygen-enriched air. The displaced by the sudden supply of oxygen-containing gas from the contaminated material gases are extracted locally, where appropriate, the sucked in time unit volume is greater than the supplied in the same unit time oxygen-containing gas.

p0012Are used for gas supply lances used, the explosive supply of the gas can be achieved in that a device, use is made, which is characterized in that according to the invention the lance at one end by the end surface of a piston can be closed, which in against the pressure of a spring a cylinder reciprocably is mounted in particular slidable, via a, preferably the plunger passes through opening communicating with the interior of an air chamber in connection, wherein the piston head is in the area opposite the opening of the lance provided with bores which in a lead located inside the piston chamber which is connected via a, loaded by a spring valve plate closable opening with the displacement of the cylinder of the piston. This device makes it possible suddenly to connect the interior of the lance to the pressure chamber of the air chamber for a short period and thereby abruptly dissipate the oxygen-containing gas from the air chamber and inject via the lance into the contaminated soil.

p0013In a further embodiment of the inventive device can be provided that the lance is inserted tightly into the air chamber, said the Ausblaseperforationen having end of the lance is located outside the air chamber. Hiebei will each lance from its associated air chamber directly served so that each lance is sufficient storage of oxygen gas.

p0014The load on the valve plate can be easily changed if the closable by the valve plate hole in one, used in the piston, preferably adjustable in the axial direction of the piston sealing ring is arranged in a further embodiment of the invention. Thus, it is possible to regulate the pressure, when reached, opens the valve plate. This regulation can be easily made if the sealing ring is screwed into the piston. To improve the abrupt gas supply in the contaminated soil, it is advantageous when the lance surmounted laterally in a special embodiment of the invention the plunger. By this means there is a large attack surface available, thereby acting in the closing direction of the piston spring loading is quickly overcome and the piston moves into the open position for the acting in the direction of the opening movement of the piston pressure of the gas in the air chamber.

p0015A rapid opening of the lance closing piston, it is beneficial if the total cross section of which is arranged in the bottom of the piston bores which connect the interior of the lance to the space in the piston is greater than the cross section of the opening through which the displacement in the cylinder with is connected to the surge tank. In order to move the piston in the cylinder wear, it is advantageous when connected in a special design of the invention, the piston on a rolling diaphragm to the cylinder.

p0016Targeted removal of displaced gases is achievable if are therefor provided to a suction pump connected lances, where appropriate, the suction pump is the outlet connected to a filter. If a filter is provided, so a possible emissions are further reduced. The suction pump is hiebei expediently dimensioned such that continuously a pressure gradient is maintained from the lances for the sudden supply of oxygen-containing gas to the lances for the discharge of the displaced gases.

p0017The invention will be described for example with reference to the drawing. Show it,<ul><li>FIG. 1, partly in section, a device suitable for carrying out the method according to the invention device,</li><li>FIG. 2, larger in relation to FIG. 1 scale, a detail of FIG. 1 in an axial section,</li><li>Fig. 3 shows the detail of FIG. 2 in a comparison with FIG. 2 amended able</li><li>Fig. 4 schematically shows a plant for the aeration of waste using the method according to the invention and the apparatus shown in Figs. 1 to 3, and</li><li>Fig. 5 compared with Figs. 2 and 3 modified variant.</li></ul>

p0018In the drawing ISTT with 1 an air tank with compressed air connection 2 designates. a lance 3 with compressed air or another oxygen-containing gas is supplied from the surge tank. 1 The lance 3 is equipped with a perforated end piece 4th Through the perforations of this end piece, the oxygen-containing gas is discharged to the outside. The lance 3 has a tight manner run through the air chamber wall pipe section 5. The tube 5 is connected to the tail 4 outside the air chamber 1 via a screw 35th The pipe piece 5 and thus the lance 3 is sealed by a piston 6, which rests on the annular surface designed as a sealing face 7 of the tube fifth The piston 6 is part of a quick exhaust valve 8, which, as described below, so set that the piston 6 abruptly returns at reaching an adjustable pressure in the air chamber 1 and the entire passage section of the pipe section 5 releases so that the oxygen-containing, in Wind boiler 1 stored gas explosively escaping under pressure through the perforated end of the lance. 3 Once the pressure has dropped in the air chamber, closes the piston 6, which is under the pressure of acting in the closing direction of the spring 9, again the opening of the tube 5 until the set pressure in the air chamber 1 is reached again and carried the next emptying explosively.

p0019The quick exhaust valve 8 in a preferred embodiment is shown in FIG. 2 in the "closed" position visible, and Fig. 3 illustrates the "open" position.

p0020The piston 6 is reciprocating in a cylinder 10 and movable back concentric admitted to the pipe piece 5 of the lance 3 in the bottom of the vessel 11 and is welded thereto. The piston 6, the end face 7 of the tube 5, the spring 9 and the cylinder 10 form the actual quick exhaust valve 8. The piston 6 can, as shown in FIGS. 2 and 3 in more detail, to slide in the cylinder 10, but the movement of the piston 6 also be wearing, if -. as shown in Figure 5 shows - the piston 6 is connected via a rolling diaphragm 41 with the cylinder 10.

p0021Into the flask 6, a plate valve 12 for controlling the movement of the piston 6 is inserted. The plate valve 12 consists of a means of thread 22 in the piston 6 axially adjustable seal 13, a valve plate 14 and a spring 15 which tends to keep the valve plate 14 in a position in which it closes a central through hole 17 of the sealing ring. 13

p0022If the air chamber with the pressurized, oxygen-containing gas, eg air, filled, the piston 6 of the quick exhaust valve 8 in the starting position according to FIG. 2. Via a (possibly several) the piston 6 passes through openings 16 reaches the gas well , in which the spring 9 is in the located above the piston 6 displacement 34th Since the plate valve 12 is also closed, and only a slight overpressure of 0.1 in the pipe piece 5 and thus in the lance 3 to 0.3 is bar, the piston 6 is firmly pressed to the end face 7 of the tube 5 until the pressure has so far risen in capacity 34, the valve plate 14 of the plate valve 12 opens, whereby the pressure is vented in the space above the piston. 6 This is possible in spite of the opening 16 since the opening cross section of the plate valve is greater by a multiple than that of the opening 16. In addition, at the moment of opening, not only the valve disk 14 of the sealing ring 13 corresponding amount applied in a the cross-section of the opening 17 with compressed but the much larger area of ​​the entire valve plate 14. As a result, the plate valve 12 is open (FIG. 3) and the gas remains despite pressure drop in capacity 34, via the holes 18 (approximately 6 pcs.) from the space 33 in the piston 6 in the pipe section 5 escape. The piston 6 is thereby relieved on the side of its spring 9 and driven by the weighing on the annular surface 19 of air pressure in the cylinder 10 (Fig. 3), thereby forming an annular opening 20 is formed, whose area is larger than the cross-sectional area of ​​the pipe piece 5 or . the lance 3. the standing in the air chamber 1 gas under pressure can thus escape explosively through the perforation 4 of the lance 3 into the ground or into the landfill. The annular surface 19 is created by the piston 6 projecting laterally against the end face of the tube piece fifth Einzuregulieren to the blow-off pressure, the sealing ring 13 of the plate valve 12 is arranged by means of the thread 22 is axially adjustable on the piston 6, whereby the spring 21, which loads the valve plate 14, can be more or less biased. Thereby, the opening pressure of the disk valve 12, which can be set between about 2 and 10 bar changes. The number of shots that can be submitted per min, therefore depends on the per unit amount of air supplied and the set opening pressure of the disk valve 12th It is usually 2-6 shots per min.

p0023Fig. 4 shows the flowchart of a ventilation system, which is equipped with lances 3 invention for aeration to household waste disposal. The designated in the drawing with 36, refuse to be disposed layer covers the soil 37 and is covered up by a layer of earth 38, is mounted on which humus. 39

p0024The lances 3 with its wind boilers 1 are connected via a pipe system 23 with a pressurized air compressor 25 of the lances 3 is supplied via a buffer air chamber 24 with compressed air. For tuning the compressed air supply pressure-reducing valves 26 may be the lances 3 connected upstream.

p0025If oxygen enrichment required may 28 fed to O₂ O₂ from a plant 40 of a mixing chamber and the compressed air are mixed doses.

p0026The landfill gas, which can pull through the soil and the humus 38 order 39 only to a small extent, are sucked through suction pipes 27, a distribution line 30 and a suction pump 29 and fed to a biofilter 31st

p0027In Fig. 4 caused by the explosive supply of oxygen-containing gas spherical shock wave 32 is shown which covers the entire landfill area around the respective lance 3 and thereby ensure the supply of oxygen throughout the body waste.