DE2821790A1 - Organic waste digestion - in heated fermenting tank with sludge circulation and gas extraction producing fertiliser - Google Patents

Abstract

Organic waste substances from animal farms, agriculture and food industry, are turned into methane gas and a deodorised high-nitrogen fertiliser in a fermenting vat. Its shape is open cylinder with a floating gas bell or a spherical container, made of suitable material, pref. plastic. Its walls contain all pipes for the inlet and outlet and for a circulation of the contents of a pump jet. This system combines a high gas yield and low operating costs with low capital costs and a long service life of the vat.

Description

Fermentation tanks with devices for continuous

or intermittent digestion of organic matter the invention is a larch tank with devices for continuous or intermittent Digestion of organic substances, mainly manure, straw, faeces, green material, Waste from household, garden, agriculture and food industry, with extraction of methane and perfectly hygienic, low-odor and nitrogen-rich natural fertilizers.

In the fermentation tank of the type mentioned above, digestion (methane fermentation) takes place as a process proceeding in the absence of oxygen, in which organic Substances of the type mentioned above due to the interaction of various microorganisms broken down into carbon dioxide and methane. In the case of decomposable sludge, more organic Digestion occurs by itself when the nitrogen and phosphorus compounds are in a favorable ratio to the carbon content and are completely free of air prevails. The decomposition of organic substances in the digester goes roughly at the same time the development of gas ahead of you. The digesters (grave containers) are mostly over terrain built with thermal insulation, with an artificial one Heat supply is favorable to decomposition. Contains the gas produced during methane fermentation with independent sludge digesters about 65 to 70% methane and 30 to 35% carbonic acid. The amount of gas depends on the digestive temperature and the fresh sludge content organic matter as well as the rotting period.

The previously known Oärbehälters suffer from the disadvantage relatively high construction costs, whereby a short service life of the operating parts can only be achieved could. Furthermore, the operating costs and the operational parts were relatively high were relatively prone to failure, with the fermentation containers known so far being a relatively had poor thermal insulation, so that an insufficient amount of gas only could be achieved.

The object of the present invention is to provide a Gärbehältsr the initially to further develop said type so that a high Cas yield with low operating costs and low construction costs as well as a long service life of the container itself can be achieved can.

This is achieved according to the present invention in that the container designed as a standing, open-topped cylinder or spherical tank and with a gas bell is provided, or as a cylinder closed at the top or as a ball with screwed manhole cover is made of a suitable material, preferably plastic, in the pipelines for loading, emptying and circulating the contents of the container are installed by means of a pump jet and for gas discharge.

An essential feature of the present invention is that so far in the city drainage for sludge treatment known fermentation tank now in inventive Way to be used for the organic substances mentioned above, with essential Benefits can be achieved.

The so-called methane bacteria are content with the waste of the Food production and the digestive residues of the higher living beings. Feces and animal excrement does not become worthless as fertilizer through this fermentation. Nitrogen, the most valuable plant nutrient that determines the yield, is found in manure and manure is mostly presented as volatile ammonia, which is the result of conventional fertilization often up to 80% is lost and the penetrating smell in the environment is fresh fertilized cultivated land.

methane digestion takes place in the absence of air. Ammonia is mineralized in the process or bound to bacterial protein (bioconversion). Therefore stays in the so-called Biodification of the Contain nitrogen and last as long as new Plant food available. A state research institute has thus in numerous Comparative tests compared to conventional manure increased yields of average 6% achieved.

Stable manure near the farm is a permanent odor nuisance and a nasty breeding ground for pesky insects.

The anaerobic treatment, on the other hand, is odorless, and that The end product, biodegradation, is also almost odorless when it is completely decomposed. Pathogens are also destroyed, especially at high fermentation temperatures. These Treatment method for organic waste in relation to public health, environmental protection and energy generation has an as yet unforeseeable significance. Subject of the present The invention is therefore to further develop the fermentation tanks mentioned at the beginning so that that the above advantages are achieved.

The Cärtemperatur determines the digestion time and thus influences the required Digestion volume is decisive. At the usual fermentation temperature of around 320 ° C the lazy period is around 30 days. According to the invention, the temperature is now increased, so that it is only 8 to 12 days in the thermophilic range around 55 C. Even The gas yield grows up to twice the amount as the cure temperature rises. Even and Accelerated digestion is finally achieved according to the invention by homogenization of the rotten matter. According to the invention it is proposed with the fermentation tank mentioned at the beginning, an undisturbed fermentation process by maintaining a constant temperature, prevention a floating cover and intensive mixing of the fresh material supplied proposed with the active putrefactive matter.

The previously known biogas plants were built from reinforced concrete. In contrast, relatively small, high-performance fermentation tanks have significant advantages. They can be manufactured in series from metal or plastic and they are therefore much cheaper. For example, conventional Shark oil tanks (known double-walled spherical containers or single-walled spherical containers) be used. Insulation with foams can be used to achieve an excellent one Thermal insulation. No massive foundation is required. The upheaval and fighting the floating cover is relatively simple and problem-free and each system can be replaced by others as a battery Plants are expanded.

According to the invention, the acquisition and operating costs are reduced in that the container is made of non-corrosive materials and the Additional units and Functional parts from existing, industrial Series productions are put together, so that with half compared to earlier required digester volume a significant reduction in the price of the system and thus also the #write rates is achieved.

According to the invention it was recognized that the manufacturing and installation Simplest form of a plastic - (; ärbehälters that of a standing cylinder with is level ground.

According to the invention, such a cylinder is used in the present invention used without short-circuit currents of the digested material to the outlet and featsetzende Lumps arise. This is avoided according to the invention in that over A sludge cone is placed at the mouth of the outlet pipe in the middle on the bottom of the container is attached, which has openings at its base, the short sliding surfaces the sludge that settles from the container wall inevitably reaches these openings bring up. This device eliminates the conventional, cone-shaped, massive one Foundation with drain in the cone tip. Instead, a horizontal layer of sand is sufficient, on which foam sheets are placed for insulation. It is not excavated earth no building permit and no craftsman necessary.

To avoid the unavoidable loss of heat through the container wall, if possible To keep it low, you have to use the container shape a cheap one Pay attention to the ratio of volume to circumferential surface.

This is the case with the cylinder when the height and diameter are approximate are the same. The ideal shape in this regard is the sphere. Be according to the invention conventional spherical tanks, such as those used as heating oil tanks, as Gärbehältsr used, with the sludge cone above the outlet and described above an externally foamed insulation such a spherical container as a fermentation container is excellently suited for undisturbed fermentation with maximum gas suction it is necessary to stir the putrefaction several times a day in order to form a to prevent gas-impermeable floating cover and use the fresh material intensively to mix the active digested mass. The circulation can be achieved by a pump jet or mechanically by means of a rung, swashplate or propeller agitator.

The digestion is expediently heated by a known one Heating coil that has a flow and return to a house central heating system or to a Hot water tank is connected. Electrical heating is also possible.

An important design feature for biogas plants is the ease of repair. The plant is said to be practically without Interruption can be operated. In addition, work on an open fermentation container is only possible due to the risk of explosion feasible with appropriate precautionary measures.

The fewer wearing parts are installed in the digester, the fewer malfunctions can result. According to the invention it is therefore provided that the moving parts are easily removable from the fermentation tank attached to this.

Closed containers are usually provided with a manhole cover Mistake. On this removable cover, you can find one that reaches far into the digested material Heating coils attached and a known propeller agitator flanged on will. This means that the digester remains free of permanently installed functional parts. In the event of malfunctions, the heating coil and agitator can be easily removed with the cover, exchanged or repaired safely.

several embodiments of the present invention will now be discussed explained in more detail with reference to the drawings. Doing this go from the drawings and theirs Description of further advantages and features of the invention.

1 shows the first embodiment of a fermentation vessel as Mid-vertical section; Fig. 2 second embodiment of a Fermentation tank as a central vertical section; 3 schematically shows a third exemplary embodiment of a Cärbehälters as a center vertical section.

The caer container shown in Fig. 1 shows a cylindrical Cross section with a container inner wall Ia, container outer wall Ib and one between insulation 1c attached to these two walls. It is essential that around the outer wall of the container Ib an outer ring 1d is arranged, in which a liquid filling for gas closure is filled. A Casglockendeckel 2a is floating on the container la, 1b, which is formed from a gas bell inner wall 2b and a gas bell outer wall 2c. The gas bell cover 2a closes off the gas storage space 2, which is above the upper limit for digested material 3 is formed.

The biomass described at the beginning is transferred via the fresh material inlet 4 is pumped in the direction of arrow 13 in the holdings and flows out of the fresh food outlet openings 4a off until the container is filled approximately to the upper limit 3 for digestion.

In operation there is a constant circulation of the digested material in that Via the circulation line 7 and the inlet openings 7a the digested material in the direction of the arrow 14 is sucked off and via the circulation line 8 with the outlet nozzle 8a in Direction of arrow 17 or 15 is pushed back into the container. The sludge builds up then in the container up to the upper limit 3 for digestion. The container bottom 1f is conical designed as a digester floor lg, on this a sludge cone 12 with base-side Openings 12a is provided. The digested sludge reaching the middle of the digester floor lg can then finally be removed via the drainage line 5 for the digested sludge will.

It is essential here that the digested sludge with the heating coil 10 is brought to a relatively high temperature, the heating coil 10 over the Heating flow 10 @ and the heating return 10b connected to a hot water heater can be.

It is essential according to the present invention that the heat of the rotten Absohlammes, which is withdrawn from the drainage line 5, still for heating of the fresh goods supplied is used in the fresh goods inlet 4. This is In the discharge line 5, a heat exchanger 6 is provided, which is shown in the direction of the arrow 13 heats the medium flowing into the fresh goods inlet 4.

The gas that forms in the gas supply space 2 can then be fed via the gas supply line 9 can be taken in the direction of the arrow, a gas meter 16 the shows the withdrawn amount.

It is essential according to the present invention that all pipelines are built like a pyramid within the digestion chamber and are stabilized 11 are held together so that the pipeline system according to the drawing as compact unit can be used in a conventional container.

Fig. 2 shows the second embodiment of a fermentation holder, the is also designed as a cylinder. Here, the same parts are the same Provided with reference numerals.

It is essential in this embodiment that the gas bell according to the embodiment in Fig. 1 is omitted and that instead the gas storage space 2 is clad with a freely foamed insulation for thermal insulation.

An essential feature of this embodiment is that the heating lengths 10 are now installed horizontally and approximately at the height of the mud guide cone near the ground of the digester floor Ig are arranged. This has the advantage that the heating coils 10 generated heat rises to the top and the digested material is mixed evenly. One Floating cover formation is carried out according to the embodiment in FIG. 1 in the present Embodiment avoided by having an outlet nozzle Bs of the pressure-side circulation line 8 is directed to the upper limit of digested material 3 and an approximately emerging Floating cover divided. A mechanical agitator can be omitted here.

It is also essential that the fresh goods inlet 4 with his Fresh product outlet opening 4a in the vicinity of the outlet nozzle 8a of the circulating pressure line 8 ends, so that the inflowing fresh material is excellent with the circulated rotten material is mixed and introduced into the digested material.

It is also essential that the gas storage space 2 is covered by a cover Ih is completed, the gas discharge line 9 opening into this cover Ih.

The third embodiment according to FIG. 3 shows a spherical tank 24, in which again the same parts are provided with the same reference numerals. Of the Ball tank 24 is supported on a foundation 23 with low manufacturing costs can be produced.

Instead of the nozzle system to prevent a floating cover beats the third embodiment according to FIG. 3 shows that the ball tank has a manhole 20, which can be closed in a gas-tight manner with a cover 21 via screw connections 22 is, with a mechanical agitator 18, which is driven by a motor 19, on the cover 21 is, and a heating coil 10 are attached.

with the attachment of said parts to the cover 21 of the manhole 20 the essential advantage is achieved that these parts are easily exchangeable and are easily accessible for repairs.

The filling of the spherical tank 24 with fresh goods takes place via the fresh goods inlet 4, which in the exemplary embodiment according to FIG. 3 obliquely upwards into the ball tank 24 is directed, so that an excellent mixing of the digested material with the fresh material is possible.

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Claims (8)

Patont claims 1. Carbehalter with devices for continuous or intermittent digestion of organic substances, mainly manure, Straw, faeces, green material, household, garden, agriculture and waste Food industry, with the extraction of methane and hygienically perfect, low-odor and high-nitrogen natural manure h n 8 t that the container is designed as a standing, open-topped cylinder and is provided with a gas bell (2a-c), or as a cylinder or cylinder closed at the top. as a ball with screwed Manhole cover (Ih) made of suitable material, preferably made of plastic, in the pipelines for charging (4), emptying (5), circulation of the container contents by means of a pump jet (7, 8) and for gas discharge (9) are installed. 2. Fermentation tank according to claim 1, d a d u r c h g e k e n n z e i c Not that it is double-walled with insulation foamed in between the walls or inside the wall with insulation attached to the outside. 3. Fermentation tank according to claim 1 and 2, d a d u r c h g e k e n n z e i c h n e t that the line pipes (4,7,8,9) laterally above the container bottom are introduced and distributed in the interior in a square conical shape as an installation unit guided upwards and provided there with a stabilization (11). 4. Fermentation tank according to claim 1 to 3, d a d u r c h g g k e n n z make sure that in the middle of the tank bottom above the sludge drainage pipe (5) a mud cone (12) is attached to prevent short-circuit current. 5. Carrier according to the preceding claims, d a d u r c h g e k e n n z E i h n e t that a at known heat exchanger (6) is placed inside or outside the container in such a way that the heat of the running sludge is released to the incoming fresh material. 6. Fermentation tank according to claim 1 to 5, d a d u r c h g e k e n n z e i c h n e t that a heating coil (10) known per se is either inside the container on the pipes (4,7,8) of the installation unit or in a horizontal arrangement in lower digestion area is attached, with a flow (10a) and a return (10b) to a known warm water heater located outside the system is connected. 7. Fermentation tank according to claim 1 to 6, d a d u r c h g e k e n n z e i c h n e t that by means of a pump known per se through the suction line (7) Digestion material sucked in and through the circulation pressure line via one or more Nozzles a pump jet is directed into the septic tank so that the floating cover is formed prevented, a possibly created floating cover destroyed and the contents thoroughly mixed without stirring up the sludge deposited on the bottom. 8. Fermentation tank according to the preceding claims, d a d u r c h g I do not know that several Container to a battery are connected or a container inside in several separate living rooms is divided.