WO2007039311A1

WO2007039311A1 - Method and device for producing fertilizer shaped bodies from fermentation remnants from biogas plants

Info

Publication number: WO2007039311A1
Application number: PCT/EP2006/009681
Authority: WO
Inventors: Jochen Tilger
Original assignee: Nawaro Bio Energie Ag
Priority date: 2005-10-06
Filing date: 2006-10-06
Publication date: 2007-04-12
Also published as: DE102005048116A1; EP1931607A1

Abstract

The inventive method for producing fertilizer shaped bodies from fermentation remnants obtained by the generation of power by fermentation in a biogas plant includes the following steps: preparing a fermentation remnant having a first nutrient content; b) separating the fermentation remnant into a solid portion and a liquid portion; c) drying the solid portion; d) increasing the nutrient content of the solid portion, and; e) converting the solid portion into fertilizer shaped bodies. The inventive method and device advantageously permit a utilization of fermentation remnants in biogas plants that is as sustainable as possible. The inventively produced fertilizer shaped body advantageously releases the contained nutrients more slowly than correspondingly unprocessed deposited fermentation remnants whereby advantageously reducing the over-fertilization of fields and the entering of nutrients, particularly nitrites, nitrates and phosphates into the groundwater. The utilization of the waste heat of a heat engine operated with the generated biogas can be advantageously used for drying the solid portion and for heating during subsequent processing of the fermentation remnants. An advantageous embodiment is provided for purifying the resulting effluent by means of evaporation and a subsequent reverse osmosis.

Description

METHOD AND DEVICE FOR PRODUCING DYE-MOLDED PORE BASKETS FROM FERMENTATION GESTURES OF BIOGAS PLANTS

5

The present invention is a method and an apparatus for producing fertilizer shaped bodies from fermentation residues obtained by the energy production by means of fermentation in a biogas plant.

0 For the recovery of agricultural wastes, the nutrients contained in the excreta are used for the fertilizer application of livestock manure in agricultural areas. Manure is used inter alia as a fuel of biogas plants, in which a fermentation to form methane-containing biogas 5 and a subsequent use of this biogas in a heat engine takes place. During the fermentation fermentation residues form, which can not be further fermented and which must be disposed of. These fermentation residues are also partially applied as fertilizer on agricultural land.

0 Such applied fertilizers have a low dry matter content and are especially liquid. These fertilizers are quickly washed out in the event of precipitation and are then no longer available as nutrients for plants planted on the agricultural land. In addition, these fertilizers are a source of nitrite and / or nitrate pollution from 5 bodies of water and groundwater, as due to the liquid form of the fertilizer much more nutrients are released than can be absorbed by the respective plants. Furthermore, it is necessary due to the very low nutrient concentration with large amount of liquid to apply large amounts of manure or digestate for proper fertilization. Due to the manure or digestate load, this requires the use of heavily loaded agricultural machines, which cause an undesirable oversized compaction of the soil. This unnecessary additional compaction of soil complicates the penetration of nutrients in the manure or digestate into the soil and worsens the ventilation of the soil.

In general, it is an object of the present invention to alleviate or even overcome the above and prior art disadvantages.

Furthermore, the present invention has the object to provide a method and an apparatus for the treatment of digestate from biogas plants, which allows improved utilization of the nutrients contained in the fermentation residues.

In addition, it is an object of the invention to provide an ecological and therefore more sustainable method of utilizing digestate. This applies in particular with regard to the improved dosage of nutrients and a gentler application of the fermentation residues to the soil.

These objects are achieved by a method and an apparatus having the features of the respective independent claims. The respective dependent claims are directed to advantageous developments.

The process according to the invention for the production of fertilizer shaped bodies from fermentation residues obtained by the energy production by means of fermentation in a biogas plant comprises the following steps: a) provision of a digestate with a first nutrient content; b) separating the digestate into a solids fraction and a liquid fraction; c) drying the solids content; d) increasing the nutrient content of the solids content; and e) reshaping the solids content in fertilizer shaped bodies. Biogas includes, for example, methane, hydrogen, carbon dioxide and hydrogen sulfide. It is produced by the anaerobic (oxygen-free) fermentation of organic material. Suitable starting materials for the technical production of biogas are fermentable, biomass-containing residues such as sewage sludge, organic waste, leftovers and liquid manure. The term biogas plant is understood to mean a plant in which biodegradable material such as, in particular, manure, plants, cereals and the like is anaerobically fermented by bacteria and biogas is obtained. The resulting biogas is used for example for the operation of heat engines, especially in combined heat and power plants.

The sequence of steps a) to e) according to the invention results in an increase in the dry matter content of the fertilizer. Under a dry matter content is the anhydrous content of solid and dissolved organic and inorganic substances. By fermentation is meant in particular the chemical conversion of substances, in particular by bacteria and enzymes, for example in the form of fermentation. The digestate is the residue of biogas production. Here, a nutrient content is understood to mean in particular a so-called NPK value, which indicates the proportions of nitrogen (N), phosphorus (P) and potassium (K) in the fertilizer. This is understood to mean, in particular, the proportions of corresponding compounds which can be absorbed and reacted by a plant. Step b) is understood in particular to mean a separation in which the liquid fraction comprises a dry matter content of less than 5% by weight (% by weight). In step d), the nutrient content is further increased, for example by adding other fertilizers, for example mineral fertilizers. In particular, in step d) the nitrogen, the phosphorus and / or the potassium content can be increased, so that here fertilizer shaped bodies can be produced which meet certain specifiable requirements, for example, are particularly suitable for a particular plant variety. In addition to an increase in the nitrogen, phosphorus and / or potassium content, it is also possible in particular to add other nutrient concentrates, for example iron or the like. In this way it allows the inventive method to produce a fertilizer "on demand", adapted to the wishes and needs of the customers.

The provision of a fertilizer shaped body has advantages over a utilization of the fermentation residues in the form of liquid fertilizer, since the fertilizer releases the nutrients present in it over a longer period of time than with liquid fertilizer. Such a fertilizer may in particular follow the principle of sustained release of the nutrients. The timeframe in which nutrients are released can be adapted in particular to the type of plants to be fertilized so that overfertilization and / or penetration of the nutrients into the groundwater can be avoided. In particular, this adaptation can be carried out in step d), in which a corresponding nutrient content is adjusted and / or in which further additives are added, for example, bind water and / or otherwise inhibit the release of nutrients in water and / or delay. For example, alumina, silica gel and / or hydrophilic polymers can be used as water-binding substances. Furthermore, for example, further additives may be added, such as in particular pesticides or the like, so as to adapt the fertilizer shaped body to special circumstances. Preferably, in step d) the addition of nutrients, an at least partially chemical conversion of substances contained in the solids content to nutrients and / or a further concentration of the solids content.

Another advantage of the fertilizer moldings compared for example to liquid manure or to liquid fermentation residues is a better way to store the fertilizer. In the storage of fertilizer moldings, so in the storage of granular media, there is no need for liquid fertilizers compelling need to use a sealed tank for storage. In addition, the fermentation residue storage capacities can be reduced by up to 80% and the transport costs by up to 60% compared with the direct application of the fermentation residues on agricultural land by the inventive method. Farther advantageous in a certain Nährstoffinenge the mass of the transported fertilizer on the agricultural land in the fertilizer shaped bodies produced by the method according to the invention is lower than in the application of liquid digestate or manure. This reduces the compaction of the soil by applying the fertilizer.

Compared to the direct application of digestate and / or manure on agricultural land also occurs a significantly lower odor nuisance. The term "fertilizer shaped body" here means any type of fertilizer in a solid, defined form, in particular pellets and prills for the fertilization of larger areas, in particular on agricultural land, in commercial and / or ornamental garden or in parks or even a fertilizer rod for use especially in potted plants ,

The dry matter content of the fertilizer shaped body is in a particularly advantageous manner after step e) at more than 80 wt .-%. Particularly advantageous is a Trockenstubstanzanteil of 85 wt .-% and more, as this has been found to be particularly advantageous for the shelf life of the fertilizer moldings, since just in this dry matter content, the moldings remain dimensionally stable in storage, the friction between adjacent bodies only to a small extent causes abrasion and, moreover, a caking of adjacent moldings is omitted, the moldings thus remain free-flowing.

A further development of the process is advantageous in which a dry matter content of 20% by weight to 30% by weight is achieved in the solids fraction in step b).

According to an advantageous embodiment of the method according to the invention, step b) comprises a mechanical separation. The implementation of a mechanical separation for the separation of a solids content and a liquid fraction has proven to be particularly advantageous because such a separation, which is based for example on a centrifugal force or the like, is easy and durable to implement.

Particularly advantageous in this connection is an advantageous development of the method according to the invention, in which step b) comprises at least one of the following methods:

Decanting and - separating by a screw separator.

Screw separators are sold for example by the company FAN Separator GmbH. After step b) and before step c), in principle, screening of the solids content can continue. Alternatively, step b) may also include this sieving. In this case, fine sieves, in particular a mesh size of about 100 to 300 μm (micrometers), are preferably used for sieving.

Also advantageous is an embodiment of the method according to the invention, in which by step c) a dry matter content of 78 wt .-% to 82% by weight is achieved. Such a dry matter content allows in a particularly advantageous manner a simple increase in the nutrient content by adding conventional concentrated fertilizers, since in such dry matter fractions, a simple and effective mixture of solid fertilizer with the solids content is possible. For example, static mixers can be used.

According to a further possible development of the method according to the invention, the fertilizer shaped bodies have a dry matter content of at least 85%. Such fertilizer tablets have a particularly good storage and transportability. Also advantageous is a development of the method according to the invention, in which a temperature of 70 to 90 ° C is present in step c). These temperatures have proved to be particularly advantageous because these temperatures can be achieved in an advantageous manner by using the waste heat of the heat engine, in particular a run with the biogas cogeneration plant. Thus, an efficient use of the waste heat of the heat engine is possible.

Also preferred is a development of the process in which the solids content produced in step b) has at least one of the following proportions: a weight fraction of nitrogen compounds of 0.6 to 0.8 wt .-%, a weight fraction of phosphorus compounds of 0.6 to 0.8 wt .-% and a weight proportion of potassium compounds of 0.2 to 0.3 wt .-%.

This is understood in particular as the nitrogen, phosphorus and / or potassium compounds which can be absorbed by plants as nutrients. In particular, these are ammonium nitrogen, nitrate nitrogen, neutral ammoniumicitratlösliches and water-soluble phosphate, water-soluble potassium oxide or chloride.

Also advantageous is a process procedure in which, after step c), the solids content has at least one of the following constituents: a weight fraction of the nitrogen compounds of from 2 to 3.5% by weight, - a weight fraction of the phosphorus compounds of from 2 to 3.5% by weight. % and a weight proportion of the potassium compounds of 0.5 to 1.5 wt .-%.

According to a further advantageous embodiment of the method according to the invention, the addition of nutrients takes place in step d). The term nutrients is understood here in particular nitrogen, phosphorus and / or potassium compounds which can be absorbed, utilized and / or reacted by plants. In particular, the nutrients may be in the form of mineral fertilizers which have a predeterminable proportion by weight of nitrogen, phosphorus and / or potassium compounds and constitute a so-called NPK fertilizer. In particular, fertilizer can be added which has a high dry matter content, in particular a dry matter content of 95 wt .-% and more or even 98 wt .-% and more. During or after the addition, the solids content is mixed with the added nutrients or with the added fertilizer. Here, in particular, a compulsory mixer can be used, which in particular comprises an agitator. Other mixing methods can be used erfϊndungsgemäß.

Particularly preferred in this context is a process in which a mineral fertilizer is added which comprises at least one compound comprising at least one of the following substances:

Nitrogen,

Phosphorus and

Potassium.

In particular, these are compounds which can be absorbed, utilized and / or reacted by a plant as a nutrient, preferably nitrites, nitrates, phosphates and / or potassium oxide.

Also preferred is a development of the method in which the solids content, a release inhibitor is added. A release inhibitor is understood as meaning a substance which slows down the release of the nutrients, in particular the nitrogen, phosphorus and / or potassium compounds. These are preferably water-binding substances such as alumina, silica gel, and / or hydrophilic polymers. According to a further advantageous embodiment of the method according to the invention is present after step d) at least one of the following substances: a weight fraction of nitrogen compounds of up to 25 wt .-%, a weight fraction of phosphorus compounds of up to 20 wt .-% and - a weight fraction of Potassium compounds of up to 30 wt .-%.

In particular, these are the weight proportions of those nitrogen, phosphorus and / or potassium compounds that can be taken up by a plant as a nutrient, recycled and / or implemented. The proportions of weight given here have proven to be particularly advantageous, since with them a good long-term effect of the fertilizer is achieved and at the same time too fast release of the fertilizer is avoided. The so-called burning and / or over-fertilization of the plants can be avoided in an advantageous manner.

According to a further advantageous embodiment of the method according to the invention, the solids content is pressed in step e). The pressing of the solids content represents a simple method of producing fertilizer shaped bodies, which enables the production of fertilizer shaped bodies in large numbers in a short time. In addition, such pressing operations, for example a type of pelleting, require relatively simple tools which are easy to maintain and are durable. A kind of extrusion of the fertilizer shaped bodies is possible and according to the invention.

According to a further advantageous embodiment of the method according to the invention fertilizer shaped bodies of a length of 2 cm to 5 cm and a diameter of 0.3 cm to 0.6 cm are formed.

These lengths and / or diameters have proven to be particularly advantageous, since here the release of nutrients in the fertilizer shaped bodies takes place relatively slowly during the fertilization of agricultural areas, so that is achieved that the release can be adapted to the needs of the plant to be fertilized and that the direct washing out of the fertilizer is avoided. This avoids over-fertilization and at least significantly reduces the amount of nutrients entering the water cycle, in particular those entering the groundwater and / or water. Also preferred are lengths of 3 cm to 4 cm and diameter of 0.4 cm to 0.5 cm.

Also advantageous is a development of the method according to the invention, in which a thorough mixing of the solids content takes place before step e).

In particular, when nutrients are added in step e), a thorough mixing of the solids content with the added nutrients is advantageous. The mixing is preferably carried out until a predeterminable fluctuation range of the concentration of at least one nutrient, preferably a proportion of nitrogen, phosphorus and / or potassium compounds, falls below a predefinable limit value. This is especially at 5 wt .-%.

Also preferred is a process procedure in which the mixing takes place until at least one width of a concentration distribution function of compounds fertilize at least one of the following substances: nitrogen; Phosphorus and potassium has been reduced by at least one predeterminable factor.

A concentration distribution function is understood here to be, in particular, a probability function which indicates the probability of the occurrence of a specific concentration of one of the specified substances and of its compounds in a predeterminable volume element. The better the mixing achieved, the narrower the concentration distribution function achieved. on. The predeterminable factors are in particular in the range from 2 to 6, preferably from 3 to 5, in particular from about 4.

Particularly preferred is a method in which the width is a full width at half height (FWHM).

In particular, thorough mixing takes place by means of a stirrer whose diameter is 1.5 meters in a container of corresponding diameter. It is preferable to mix for 20 minutes at a rotation frequency of 0.5 Hz.

According to the invention, a digestate from a biogas plant is provided in step a).

According to a further advantageous embodiment of the method according to the invention at least one of the following substances is fermented in the biogas plant to form a gas mixture: manure,

Plant silage, - cereals and water.

Under liquid manure here are understood in particular excrement and / or urine of animals, preferably livestock. Plant silage is understood to mean, in particular, plant material conserved by lactic acid fermentation.

The manure is characterized in particular by a high cellulose content. As plant silage in particular grain silage, preferably corn silage or green leaf silage is used. In particular, wheat is understood to mean wheat, rye, oats, barley, with rye being particularly preferred. The plant silage offers a good biogas yield with the least possible use, especially from a cost point of view. The addition of grain is preferably discontinuous, since the fermentation of cereals begins very quickly. Thus, the targeted addition of grain times of low ferocity can be stopped. The proportion of water determines the consistency of the mixture to be fermented, in particular so that the fermentation and the rheology of the mixture can be adjusted. The manure stabilizes the proportion, growth and / or activity of the fermentation-carrying bacteria.

It is preferred that in the biogas plant, a substance mixture is fermented, which includes the following proportions: a slurry content of 15 wt .-% to 18 wt .-%; a plant silage content of from 58% to 61% by weight; a cereal portion of 4 wt .-% to 6 wt .-% and - water of 18 wt .-% to 21 wt .-%.

According to a further advantageous embodiment of the method according to the invention, the gas mixture produced comprises methane.

According to a further advantageous embodiment of the method according to the invention, a gas mixture is produced in the biogas plant, which is supplied to a heat engine.

In particular, the heat engine may be an internal combustion engine, preferably a combined heat and power plant, preferably comprising a combined heat and power unit. Furthermore, it is inventively possible, for example, to use a fuel cell as a heat engine.

According to a further advantageous embodiment of the method according to the invention, at least part of the waste heat of the heat engine of the gas mixture is used for at least one of the following processes: Step c),

Heating at least one fermenter tank,

Heating of manure and evaporation of the liquid content.

The advantageous development of the method described here can advantageously also be carried out independently of the other method features described and, in particular, independently of the steps a) to e) during the work-up of the fermentation residues of biogas plants. A fermenter container is understood here to mean, in particular, a container in which the fermentation can take place in the biogas plant. The heating of the manure is used in particular for the hygienization of the manure and preferably takes place up to a temperature of 70 ° C or more. Hygienization is understood in particular to mean the reduction and / or elimination of pathogens and / or phytopathogens. The use described here of the waste heat of the heat engine advantageously increases the overall efficiency of the entire system and in particular leads to a sustainable use of the educts used.

According to a further advantageous embodiment of the method according to the invention, the liquid fraction is subjected to evaporation to produce a concentrate.

The evaporation of the liquid fraction described here can advantageously also independently of the other described process characteristics and in particular independently of the steps a) to e) in the processing of

Fermentation residues of biogas plants are carried out. In addition to a concentrate in which the nutrient content of the liquid fraction is increased, a condensate is produced whose nutrient content is reduced compared to the original nutrient content of the liquid fraction. Preferred is a development of the method in which a vacuum evaporation is carried out.

In particular, a method is preferred in which the vacuum evaporation is carried out at a temperature of 65 ° C to 90 ° C.

Further preferred is a process in which the vacuum evaporation is carried out at a pressure of 5 Torr (about 667 Pascal) to 25 Torr (about 3333 PasCal). Particularly preferred are a pressure of 16 Torr (about 2133 Pascals) and / or a pressure generated by a water jet pump.

A further development of the process is advantageous in which the concentrate has at least one of the following proportions of substance: a proportion by weight of nitrogen compounds of from 0.5% by weight to 1.5% by weight; a weight proportion of phosphorus compounds of 0.05 to 0.2 wt .-% and a weight proportion of potassium compounds of 0.5 to 1, 5 wt .-%.

Also preferred is a development of the process in which the condensate after evaporation has at least one of the following constituents:

80 to 100 mg / 1 chemical oxygen demand (COD),

20 to 40 mg / l ammonium nitrogen (NH ₄ -N),

5 to 10 mg / l phosphorus and - 20 to 50 mg / l nitrogen.

The amounts of phosphorus, nitrogen and ammonium nitrogen are understood here to mean, in particular, the corresponding amounts of compounds comprising these substances. By COD is meant here in particular a sum parameter, which designates the quantity of all organic compounds in the water including the hardly degradable connections. The COD value is specifically understood to indicate the amount of oxygen consumed to oxidize all of the organic matter contained in the water using, for example, potassium dichromate as the oxidant. The COD is understood in particular according to DIN 38 409-H41.

According to a further advantageous embodiment of the method according to the invention, a condensate is formed which is at least partially subjected to reverse osmosis.

The condensate is preferably formed as part of an evaporation of the liquid fraction. The implementation of a reverse osmosis in the condensate can be carried out in an advantageous manner, regardless of the other described process characteristics and in particular independently of the steps a) to e) in the processing of fermentation residues of biogas plants. Preference is given to a process management in which the condensate is forced under high pressure onto a semipermeable, in particular water-permeable membrane. In particular, here a membrane of the type Filmtec BW 30-400, distributed by imb + frings watersystems gmbh can be used. Preferably, the condensate is subjected to reverse osmosis at a pressure of 20 to 25 bar.

According to a further advantageous embodiment of the method according to the invention, the condensate has at least one of the following constituents: at most 90 mg / 1 chemical oxygen demand (COD), at most 20 mg / 1 biochemical oxygen demand after 5 days (BOD 5,), - at most 10 mg / 1 ammonium nitrogen (NH ₄ -N), not more than 5 mg / 1 phosphorus and not more than 18 mg / 1 nitrogen.

These proportions are achieved in particular after a reverse osmosis, preferably with the parameters given above. The biochemical oxygen requirement after 5 days is understood in particular to mean the amount of oxygen which Bacteria and other microorganisms in a sample of the condensate over a period of 5 days at a temperature of 20 ° C need to aerobically degrade the ingredients. By BOD 5 is meant a measure of the amount of oxygen needed in a given time for biodegradation of organic wastewater ingredients. The proportions of phosphorus, ammonium nitrogen and nitrogen are understood in particular to mean the corresponding proportion of compounds containing these substances. These limit values have proved to be harmless, so that the condensate after the reverse osmosis is able to flow and / or flood.

Particularly advantageous is a Verfahrensfuhrung, in addition to the production of fertilizer moldings in addition to the above-described waste heat recovery and the treatment of the condensate is used by reverse osmosis, since there is a good use of the energy present in the educts introduced into the biogas plant at the same time as low as possible load the environment with undesirable substances is achieved.

According to a further aspect of the present invention, an apparatus for producing fertilizer shaped bodies from fermentation residues obtained by energy generation by means of fermentation in a biogas plant is proposed, comprising

A) means for providing a digestate;

B) means for separating the digestate into a solids fraction and a liquid fraction; C) means for drying the solids content;

D) means for increasing the nutrient content in the solids content; and

E) Means for forming in fertilizer shaped body.

The device according to the invention is particularly suitable for carrying out the method according to the invention. The means A) preferably contain a biogas plant. According to an advantageous embodiment of the device according to the invention, the means B) include mechanical release agents.

According to a further advantageous embodiment of the device according to the invention, the means B) comprise at least one of the following devices: at least one decanter and at least one screw separator.

According to a further advantageous embodiment of the device according to the invention, means for generating a biogas and at least one heat engine for implementing at least parts of the biogas are formed.

A heat engine is understood to mean in particular an internal combustion engine, preferably a combined heat and power plant, preferably comprising a combined heat and power unit and / or a fuel cell.

According to a further advantageous embodiment of the device according to the invention, the means for generating a biogas comprise at least one fermenter container.

According to a further advantageous embodiment of the device according to the invention evaporation means for the evaporation of the liquid fraction to form a concentrate and a condensate are formed. Preferred here is a development in which the evaporation means comprise evacuating agent.

According to a further advantageous embodiment of the device according to the invention at least one of the following heating means is formed: first heating means for heating the fermenter tank; second heating means for heating the means C); third heating means for heating the evaporation means and fourth heating means for heating a manure storage tank.

By means of the first, second, third and / or fourth heating means can be achieved in a particularly advantageous manner, a simple process control of the fermentation process, as well as the treatment of the digestate.

The heating means, in particular also in connection with a use of the waste heat of a heat engine, can also be realized in isolation, ie in particular without the means A) to E), in particular in connection with biogas plants.

According to a further advantageous embodiment of the device according to the invention, the heating means use at least a portion of the waste heat of the heat engine. This can be done in particular by forming appropriate heat exchanger.

According to a further advantageous embodiment of the device according to the invention means for performing a reverse osmosis are formed, which are connectable to the evaporation means, that the means for carrying out a reverse osmosis can be acted upon with the condensate.

Thus, in a particularly advantageous manner, a further purification of the condensate take place, which leads to such pollutant contents that an introduction of the condensate in a receiving water and / or a Verregnung of the condensate is unobjectionably lent possible. Under a receiving water is understood in particular a stagnant or flowing water, preferably a flowing water. By performing the reverse osmosis can thus be dispensed with advantageously in a further purification of the condensate in a sewage treatment plant. Under a Verregnung is understood in particular the application of the condensate on free areas, especially on agricultural land. The design of the means for performing a reverse osmosis is in every biogas plant and thus independently of the other features disclosed herein of a corresponding device possible and according to the invention. In particular, the means for performing a reverse osmosis can be designed independently of the means A) to E) for processing the fermentation residues of a biogas plant.

A method for producing fertilizer shaped bodies can be carried out in particular in an apparatus according to the invention.

According to a further aspect of the present invention, a method for producing plants is proposed, wherein fertilizer in the form of at least one fertilizer shaped body produced by a method according to the invention is applied to a usable area.

Under plants are here in particular crops and flowers to understand. A usable area is to be understood as meaning in particular an agricultural area, preferably a field. Preferably, the application of the fertilizer takes place before, simultaneously with and / or after planting or sowing the plants. Advantageously, the time of application of the fertilizer to the type of plant, the nature of the soil, the geographical location of the floor space and / or the local micro-climate can be adjusted.

The details and advantages disclosed for the method according to the invention for the production of a fertilizer shaped article can be applied and applied in the same way to the device according to the invention. The details and advantages disclosed for the device according to the invention are equally transferable and applicable to the method according to the invention. In the following, the invention will be explained in more detail with reference to the accompanying drawings, without the invention being limited to the embodiments and advantages shown there. It shows: Fig. 1 shows schematically an exemplary embodiment of a device according to the invention.

Fig. 1 shows schematically an exemplary embodiment of a device according to the invention. This includes means 1 for providing a digestate, which means 2 for providing plant silage, cereals and / or water, at least one slurry tank 3 and at least one fermenter tank 4 include. The fermenter container 4 is connected to a Biogassammeiraum 5, which is connectable to a heat engine 6. The biogas produced in the fermenter container 4 by fermentation is collected in the biogas collecting space 5 and converted into the heat engine 5, for example, burned and used to generate electricity. The digestate produced during fermentation is collected in the digestate collector 7. This Gärrestsammelbehälter 7 is connected to means 8 for separating the digestate into a solids content and a liquid content. With the means 8 means 9 for drying the solids content can be connected, in which a drying of the solids content takes place.

The means 9 can be connected to means 10 for increasing the nutrient content, which comprise, for example, a mixer with which fertilizer from a fertilizer storage container 11 can be mixed into the solids fraction. The means 10 are connected to means 12 for forming the solids content in fertilizer shaped body. These means 12 include, for example, a pelleting and / or extrusion tool.

The means 8 for separating the digestate into a solids fraction and a liquid fraction are so connectable with evaporation means 13 that in this only the liquid fraction is introduced. In this evaporation means 13, an evaporation of the liquid fraction to form a concentrate, which is usable as a liquid fertilizer, and a condensate, which is discharged after a work-up to the environment and / or initiates as starting material in the fermenter tank 4 bar is. Evacuation means 14 are formed, by means of which a negative pressure can be applied to the evaporation means 13.

Furthermore, means 15 for performing a reverse osmosis are formed, which are connectable to the evaporation means 14, that the condensate is subjected to a reverse osmosis. The condensate purified by reverse osmosis can be released to the environment. The means 15 for performing a reverse osmosis are connected to pressure build-up means 21, for example a suitably designed pump. There are first heating means 16 for heating the fermenter container 4, second heating means 17 for heating the means 9 for drying the solids content, third heating means 18 for heating the evaporation means 13 and fourth heating means 19 for heating the slurry tank 3. The heating of the manure storage container 3 serves to hygienize the manure. The heating means 16, 17, 18, 19 are heated via heat pipes 20 via the waste heat of the heat engine 6. In this case, appropriately suitable heat media such as oils, water, etc. can be used in the heat pipes 20 and be formed corresponding heat exchangers.

The method according to the invention and the device according to the invention advantageously permit the most sustainable use of the fermentation residues in biogas plants. The fertilizer shaped body produced according to the invention advantageously releases the nutrients contained more slowly than appropriately applied fermentation residues so that the overfertilization of fields and the entry of nutrients, in particular nitrites, nitrates and phosphates into the groundwater are advantageously reduced. In particular, the use of the waste heat of a heat engine operated with the generated biogas for drying the solids content and for heating in the further processing of the fermentation residues can be used in an advantageous manner. An advantageous development is directed to the purification of the resulting effluents by means of evaporation and subsequent reverse osmosis. LIST OF REFERENCE NUMBERS

1 means for providing a digestate 2 means for providing silage, grain and / or water

3 slurry tank

4 fermenter tanks

5 biogas collection room

6 Heat engine 7 Gärrestsammelbehälter

8 means for separating the digestate in a solids content and a liquid content

9 means for drying the solids content

10 Nutrient Content Enhancers 11 Fertilizer sump

12 means for forming in fertilizer shaped body

13 evaporation agent

14 evacuees

15 means for performing a reverse osmosis 16 first heating means

17 second heating means

18 third heating means

19 fourth heating means

20 heat conduction 21 pressure build-up agent

Claims

claims

1. A process for the production of fertilizer moldings obtained by the energy production by fermentation in a biogas plant

Digestate containing the following steps: a) providing a digestate with a first nutrient content; b) separating the digestate into a solids fraction and a liquid fraction; c) drying the solids content; d) increasing the nutrient content of the solids content; and e) reshaping of the solids content in fertilizer shaped bodies.

2. The method of claim 1, wherein step b) comprises a mechanical separation.

3. The method according to any one of the preceding claims, wherein the fertilizer shaped bodies have a dry matter content of at least 85%.

4. The method according to any one of the preceding claims, wherein in step d) the addition of nutrients takes place.

5. The method of claim 4, wherein a mineral fertilizer is added, comprising at least one compound comprising at least one of the following substances:

Nitrogen, phosphorus and potassium.

6. The method according to any one of the preceding claims, wherein after step d) at least one of the following substance proportions is present: a weight proportion of nitrogen compounds of up to 25 wt .-%, a weight proportion of phosphorus compounds of up to 20 wt .-% and a weight proportion of potassium compounds of up to 30 wt .-%.

7. The method according to any one of the preceding claims, wherein in step e) the solids content is pressed.

8. The method according to any one of the preceding claims, wherein the fertilizer shaped article body of a length of 2 cm to 5 cm and a diameter of

0.3 cm to 0.6 cm are formed.

9. The method according to any one of the preceding claims, wherein in the biogas plant, a gas mixture is generated, which is supplied to a heat engine (6).

10. The method of claim 9, wherein at least a portion of the waste heat of the heat engine (6) of the gas mixture is used for at least one of the following processes: - step c),

Heating at least one fermenter tank (3),

Heating of manure and evaporation of the liquid content.

11. The method according to any one of the preceding claims, wherein the liquid portion of an evaporation is subjected to the production of a concentrate.

12. The method according to any one of the preceding claims, in which a condensate arises, which is at least partially subjected to reverse osmosis.

13. The method of claim 12, wherein the condensate has at least one of the following substance proportions: not more than 90 mg / 1 chemical oxygen demand (COD), - at most 20 mg / 1 biochemical oxygen demand after 5 days

(BOD 5), not more than 10 mg / 1 ammonium nitrogen (NH ₄ -N), not more than 5 mg / 1 phosphorus and not more than 18 mg / 1 nitrogen.

14. An apparatus for producing fertilizer shaped bodies from fermentation residues obtained by the energy production by means of fermentation in a biogas plant, in particular by the method according to one of claims 1 to 13, comprising A) means (1) for providing a digestate;

B) means (8) for separating the digestate into a solids fraction and a liquid fraction;

C) means (9) for drying the solids content;

D) means (10) for increasing the nutrient content in the solids content; and E) means (12) for forming into fertilizer shaped bodies.

15. The apparatus of claim 14, wherein the means B) include mechanical release agents.

16. The apparatus of claim 14 or 15, wherein means are formed for generating a biogas and at least one heat engine (6) for implementing at least parts of the biogas.

17. Device according to one of claims 14 to 16, wherein the means for generating a biogas include at least one fermenter container (4).

18. Device according to one of claims 14 to 17, wherein the evaporation means (13) are formed for the evaporation of the liquid fraction to form a concentrate and a condensate.

19. The apparatus of claim 14 to 18, wherein at least one of the following heating means is formed: first heating means (16) for heating the fermenter container (4); second heating means (17) for heating the means C); third heating means (18) for heating the evaporation means and fourth heating means (19) for heating a slurry tank.

20. The apparatus of claim 19, wherein the heating means (16, 17, 18, 19) use at least a portion of the waste heat of the heat engine (6).

21. Device according to one of claims 18 to 20, wherein the means (15) are designed for performing a reverse osmosis, which are so connected to the evaporation means (13) that the means for performing a reverse osmosis are acted upon with the condensate.

22. A process for the production of fertilizer shaped bodies using a device according to one of claims 14 to 21.

23. A method for producing plants, wherein fertilizer in the form of at least one fertilizer shaped body, produced by a method according to one of claims 1 to 13 or 22 is applied to a usable area.