WO2019151892A1

WO2019151892A1 - Granulated fertilizer made from sunflower husk ash and method of producing same

Info

Publication number: WO2019151892A1
Application number: PCT/RU2018/000666
Authority: WO
Inventors: Антон Юлианович СЕРЕДКИН; Игорь Иванович БРУСЕНКО
Original assignee: Общество с ограниченной ответственностью "Техносервис"
Priority date: 2018-01-31
Filing date: 2018-10-09
Publication date: 2019-08-08
Also published as: RU2660262C1

Abstract

A granulated fertilizer consists of round granules which are formed from agglomerated particles of sunflower husk ash moistened with water and have a coreless structure, i.e. they do not have a core made of cinder, and are formed without the use of seed particles. In addition, they have a compacted surface layer. The average strength of the granules is no lower than 4.0 MPa and the softening factor is 2.2-2.6. A method of producing a granulated fertilizer comprises forming raw granules consisting of sunflower husk ash and added water, and subsequently pelletizing the raw granules on a disc granulator using water as a moistening component, while ensuring spontaneous rolling of the granules over the side of the disc of the disc granulator.

Description

Granular fertilizer from ash husks of sunflower and method for its production

Technical field

The group of inventions relates to a method for producing mineral fertilizer and to mineral fertilizer obtained from industrial utilization products, namely from sunflower husk ash. The fertilizer obtained from the sunflower husk ash can be used in household plots, in agriculture and forestry.

Enterprises that process agricultural products have large-tonnage volumes of plant waste. In particular, in oil extraction plants that process sunflower seeds, a large amount of husk is formed. In the production of sunflower oil annually in Russia from 1 to 2 million tons of such waste is generated. For disposal, husk is used as an alternative fuel in fuel boilers, while receiving an incombustible residue - ash.

State of the art

Sunflower husk ash can quickly reduce the acidity of the soil, which needs liming, so the ash is used as an alkaline fertilizer. It complicates the development of root and extra root rot, pathogens. Sunflower husk ash as a chlorine-free mineral fertilizer is produced by many enterprises [information can be found on the Internet at https://mariupol.flagma.ua/zola-luzgi-podsolnechnika-o2877649.html,

https://slavyansk.flagma.ua/zola-luzgi-podsolnechnika-o3142389.html]. By physical state is a finely divided dry loose mixture with a particle size of several microns to 0.01 mm. Ash is applied to the soil in household plots by watering the prepared aqueous solution or by scattering manually. Strong dusting, and, consequently, uneven distribution over the area, does not allow the ash to be introduced into the soil mechanically using agricultural machinery.

One of the methods to reduce the dust formation of bulk substances and fertilizers, in particular, is granulation.

To obtain rounded granules, various granulator designs are used. In rotor (paddle) granulators [see for example, USSR copyright certificates N "1005879, N" 1318279] use various liquid binders - substances with pronounced astringent properties. In such granulators, the powder and liquid flow mixed by the blades of the shaft moves along a helical line along the inner surface of the housing towards the outlet. In this case, the particles of the material, colliding with each other, stick together, forming agglomerates, which turn into granules.

Known technology for producing rounded granules in dish-shaped granulators. Known granular fertilizer from a powdery material, in particular wedge-lime, obtained by rolling in a disk granulator using the aqueous phase as an aqueous phase for extracting soluble components from the same fertilizer [patent RU2084276]. The disadvantage of fertilizer is the need to use hoods in the technology of its manufacture, which is not applicable for granular fertilizers from wood ash.

Organic-mineral fertilizer EcoPlan is known [the information can be found on the Internet at htps: // dim-sad- gorod.com/products/ekoplant- 1 -kg /], which includes sunflower husk ash. Unfortunately, the manufacturer does not provide information on either the production method or the organic component of the fertilizer, but it is highly likely that the introduction of this particular component makes the fertilizer extremely heterogeneous in fractional composition. The manufacturer presents EcoPlan as a granular fertilizer, but it is not. From the photograph shown on the site, it is clear that these are not granules, but loose pelletized agglomeration particles in the form of irregularly crushed crumbs. Such fertilizer crumbles during transportation, partially returning to its original powder state. A large spread in fractional composition leads to uneven fertilizer application.

The problem of granulation of ash obtained during the combustion of plants (wood ash, sunflower husk ash) is caused, first of all, by the properties of the feedstock. Ash is an unplastic raw material that does not have astringent and finely divided materials. It is known that the smaller the size of the dust particles, the less their ability to wet. Wetting is prevented by the gas shell forming around small particles of ash. This circumstance makes it difficult to organize the process of granule formation at the initial stage of granule nucleation using water as a binding agent. The use of other binding agents instead of water negatively affects the chemical composition of the fertilizer.

The technical problem underlying this invention is the creation of granular fertilizer and a method for its production exclusively from powder of sunflower husk ash and water as a moisturizing component. By its physical characteristics, the sunflower husk ash is close to wood ash.

An attempt to solve this technical problem using finely divided wood ash was made using the technology of granulation on a plate granulator.

As a prototype of the first object - granular fertilizer, the fertilizer described in patent RU 2631073 (patent holder of Tekhnoservis LLC) obtained from wood ash by rolling in a plate granulator was adopted. Fertilizer granules have a core (seed granulation) and a coating layer obtained by rolling wood ash on a plate granulator using water as a moisturizing component. The particle size of the wood ash used is from a few microns to 0.01 mm. The core of the granule is the screening of wood ash in the form of particles up to 1.5 mm in diameter obtained by sieving, that is, particles of slag, the so-called no-burn.

As a prototype of the second object - a method of producing fertilizer, the method is adopted, described in the aforementioned patent RU 2631073, which describes in detail the operating modes of a plate granulator in the process of manufacturing granular fertilizer by forming on the core (slag particles up to 1.5 mm) a covering layer of wood ash using water as a moisturizing component.

In the granulation process described in the prototype, moistened wood ash with the participation of physical phenomena occurring in the separation of liquid and solid phases, is aggregated into loose lumps. The latter, due to mutual influence, as well as centrifugal forces, are compacted and lose excess water forming a film on the surface of the granule, which, in turn, adsorbs a portion of ash and thus increasing its volume. When pelletizing on plates, the enlargement of granules is accompanied by their movement to surface horizons. However, to initiate the process, it is necessary to use a seed, which subsequently becomes the core of the obtained granules. As seeds, ash screening particles are used. Such particles have an irregular shape with torn edges, and the pelletizing of such particles in water-soaked ash on a plate granulator is very problematic. Unfortunately, the patent RU2631073 presents the results of the method on a laboratory plate granulator with the supply of ash to the granulator in the amount of 0.5 kg / min. As shown by the tests of the method according to patent RU2631073, produced on an industrial disk granulator, the obtained fertilizer of commercial quality (smooth rounded granules) has a large variation in particle size distribution, and granules with a diameter of 5-7 mm prevail. This is due to the fact that in order for granules with cores made of slag particles to acquire a rounded shape, in which they spontaneously roll through the granulator plate, it is necessary to build up a significant covering layer that evens out the roundness of the form. Granules with a smaller diameter of 2-4 mm are rolled from the granulator together with fine particles, that is, they are not marketable products, which leads to a significant screening.

It should be noted that granular fertilizer from ash is a fertilizer of prolonged action, it slowly passes into a dissolved state, in which mineral substances can be absorbed by plants. Therefore, in personal subsidiary plots, when it is desirable to quickly increase crop yields, the use of ash with granules of 5-7 mm is unreasonably costly and therefore unacceptable. In addition, pellet cores obtained from screenings are poor wetted and, accordingly, poorly enveloped by particles of wet ash, which leads to the fact that the adhesion forces of the core and the coating layer are low, and accordingly, the granules of the prototype in reality have a relatively low strength (2.0 MPa) and a significant spread in the value of this indicator. The insufficiently high strength leads to the fact that when transporting and storing bulk bags (40-50 kg) in bulk, dropping the bags during loading and unloading, the granules are crushed due to pressure or friction, which is accompanied by the formation of fine particles, that is, a significant part of the granules passes in its primary powder state. The presence of fine particles worsens the working conditions of machine operators, increases losses and leads to uneven spread of fertilizer over the area.

Another disadvantage of the prototype, due to the presence of a core from slag, is that this core is practically insoluble in moist soil, and therefore it is useless ballast in the composition of granular fertilizers.

Thus, there is a technical contradiction. On the one hand, the larger the radius of the granule, the stronger it is, since the covering layer eliminates the negative effect of the yard (foreign body) on the strength of the granule. On the other hand, the larger the radius of the granule, the longer it dissolves, the longer its nutrients are released. It should be borne in mind that the ash itself (feedstock) is a fertilizer of prolonged action. Granulation further increases the prolongation, because the granules themselves must go into a softened state in the soil and eventually collapse, returning the ash to its original finely divided state. One pellet with a diameter of 6 mm by the amount of ash contained in it is 3-5 granules with a diameter of 2-3 mm, which dissolve much faster. Thus, 6 mm granules have an unjustifiably prolonged effect, which makes them inappropriate to use in subsidiary plots and in summer cottages. However, fertilizer with granules up to 6-7 mm can be used in industrial agriculture and forestry for renewal and growing of forests.

Disclosure of invention

The problem solved by the group of inventions is to expand the arsenal of technical means in the field of mineral fertilizers, namely, to create a new granular fertilizer with high consumer properties from the sunflower husk ash and the method for its production, devoid of the disadvantages of the prototype. The inventive method allows to obtain a qualitatively new mineral fertilizer, the rounded granules of which are entirely (without the use of seed slag particles) formed from husk ash and have the desired properties - increased strength and at the same time set softening factor (the ratio of the strength of the granules in the dry state to the strength of the granules in a water-saturated state) , which leads to their more rapid destruction in the moisture contained in the soil (up to 0.5-3 years).

The problem in the first object of the invention (granular fertilizer) is solved in that the granular fertilizer consists of round granules, which are formed from agglomerated particles of sunflower husk ash moistened with water, have a nuclear-free structure, that is, they do not have a slag core and are formed without the use of seed particles. Moreover, they have a compacted surface layer. The average strength of the granules is at least 4.0 MPa and a softening factor of 2.2-2.6. The fertilizer contains nutrients for plants in the following ratio: P ₂ O ₅ - 3.26-7.89% of the _mass , K ₂ O - 32.5-44.8% of the _mass , CaO - 9.5-15.4% of the _mass , MgO - 7.5-15.6% of the _mass , SO ₃ - 11.1-13.5 _mass%, Na ₂ 0 -1,3-1, 7% _ma ss, SiO _{2 -} 1.5 to 2.1% _{by weight of} trace elements, including Zn, Cu, Ba, Fe, V, Cr, Mn, Mo, Co, - not less than 2% of the _mass .

The composition of the granular fertilizer is fully consistent with the composition of the sunflower husk ash and varies depending on its initial composition. In turn, this depends on the soil of sunflower growth, fertilizers used, climatic conditions and other factors.

In relation to the use in subsidiary farms, the fertilizer has fractions of granules with a diameter of 2-4 mm more than 80% of the total composition.

The problem in the second object of the invention (a method for producing granular fertilizer) is solved by the fact that the claimed method includes the formation of raw granules from sunflower husk ash with the addition of water, carried out in a mixer-granulator, and subsequent rolling of the raw granules on a plate granulator using water as a moisturizing component. This ensures the spontaneous rolling of granules across the side of the plate of a dish-shaped granulator.

At the first stage, any mixer granulator suitable for these purposes can be used. It is preferable to use in the first stage a rotary mixer-granulator with a paddle rotor.

Embodiments of the invention

In order to better demonstrate the distinguishing features of the invention, as an example, not having any restrictive nature, the following describes a preferred implementation option in which for the formation of the core and the covering layer Hearth ash of a mini-CHP was used, obtained by burning sunflower husks formed at oil extraction plants.

Physical state of the initial granule-forming material - ashes: powdery, dry finely dispersed (dusty) mixture.

The particle size is from a few microns to 0.01 mm. The composition of the nutrients is given above.

Ash is loaded into a continuous rotary mixer-granulator, for example, an apparatus with a horizontal rotor blade. In the mixer-granulator, the ash is wetted with water supplied through nozzles and forms a homogeneous mass. The granulation process is carried out under the action of centrifugal forces with intensive exposure to the granulated mixture of blades of a rotating working body. The turbulent movement of solid particles, determined by the design of the rotor, ensures uniform distribution of the liquid phase between the ash particles in the entire volume of the moving material and high dynamic loads, resulting in the formation of raw granules of a given size. However, the obtained raw granules do not have the type of marketable products, because have a rough surface with growths of small agglomerated particles of ash, which later (transportation, storage) crumble, and part of the granule again passes into a dusty state.

To bring the product to condition, the raw granules are fed to a dish-shaped granulator plate, to which water is also fed through nozzles. When rolling raw granules on a dish-shaped granulator, surface roughness is smoothed out and their density and granularity are increased. In the process of subsequent drying, the granules gain strength. Due to the fine dispersion of the starting material, the dried granules are capable of maintain a sufficiently high strength, the reason for which is the so-called “contact-condensation” intermolecular attraction forces, the level of which is proportional to the dispersion of the ash.

Thus, as a result of the implementation of the above method, a granular fertilizer was obtained at the output, the granules of which have a fraction of 2-4 mm in diameter demanded by the mass consumer that exceeds 80% of the total volume, that is, increased uniformity of the dispersed composition of the granules.

If necessary, increase the diameter of the granules (obtaining fertilizer of increased prolongation with a predominance of a fraction with a diameter of 5-7 mm), it is possible to change the operating modes of the granulator and add ash to its plate. Studies of the resulting product showed that the composition of the fertilizer for plant nutrients corresponds to the composition of the original husk ash (see above). The granules have a rounded shape. The sphericity coefficient is not less than 0.7-0, 8. Unlike the prototype, the charged granules have a nuclear-free structure, that is, they do not have slag cores, are formed without “seed particles”, which leads to a decrease in stresses in the contact zone during drying. The average granular strength is at least 4 MPa, and in some cases reaches 4.7 MPa, which is 20-25% higher than the strength of wood ash granules.

Studies have made it possible to establish the following characteristics of the obtained granular fertilizer - bulk density of 1000 kg / m ³ (± 1%), average statistical density of granules 1700 kg / m. In addition, the active porosity of the granules (water absorption) is 30-40%, the average strength of the granules in a water-saturated state is 2.05 MPa. In this case, the average softening factor characterizing a decrease in strength in a water-saturated state, then there is the ability to decompose more quickly in a humid environment, is - 2.3. Potassium in ash is contained in the form of potash (potassium carbonate), which is highly soluble in water. The solubility in water of husk ash granules is 5-8 times higher than wood ash.

The listed characteristics indicate that the granules, having got into moist soil, soften and transfer to the initial finely dispersed state (the state of the initial ash), and the water-soluble compounds that make up it begin to dissolve. In this case, unlike the prototype, the entire granule decomposes as does not have a foreign core. When the structure of the granule is destroyed, the sparingly soluble compounds are processed by microorganisms, which makes them suitable for use by plants. An increase in the rate of release of nutrients and the transition to a form assimilated by plants leads to a more rapid increase in yield in the early stages of fertilizer application, which is important for its use in home gardens.

The resulting increase in strength and stability of this indicator, which is obtained as a result of the application of the proposed method, makes it possible to dump granules into bags of increased capacity (up to 1-3 m ³ ) and store them in a warehouse on heavy cargo racks after completion of the technological process. In the same bags, the fertilizer can be delivered by road and railway wagons, as well as sea containers to the place of packaging and sale to the consumer. As practice has shown, granular fertilizer delivered from husk ash delivered to harsh consumer conditions is not crushed due to pressure and friction, which eliminates dusting and losses.

Claims

CLAIM

1. Granular fertilizer, characterized in that the granules are rounded in shape, formed from agglomerated particles of sunflower husk ash moistened with water, have a nuclear-free structure with a compacted surface layer, and the average statistical strength of the granules is at least 4.0 MPa and softening factor 2.2 - 2.6.

2. Granular fertilizer according to claim 1, characterized in that it contains nutrients for plants in the following ratio: P ₂ 0 ₅ - 3.26-7.89% of the _mass , K ₂ O - 32.5-44.8% of the _mass , CaO - 9.5-15.4% of the _mass MgO - 7.5-15.6% by _mass , SO ₃ - 11.1-13.5% by _mass , Na ₂ 0 -1.3-1, 7% by _mass, Si0 ₂ . 1.5 - 2.1% of the _{mass of} trace elements, including Zn, Cu, B a, Fe, B, Cr, Mn, Mo, Co, - not less than

^ 2% ^{/ and} mass.

3. Granular fertilizer according to claim 1 or 2, characterized in that the fraction of granules with a diameter of 2-4 mm is more than 80%.

4. A method of producing granular fertilizer, characterized in that it includes the formation of raw granules, consisting of sunflower husk ash with the addition of water, carried out in a mixer-granulator, and subsequent rolling of the raw granules on a plate granulator using water as a moisturizing component, ensuring spontaneous rolling of the granules across the board of a dish-shaped granulator.

5. The method of producing granular fertilizer according to claim 4, characterized in that at the first stage a rotary mixer-granulator is used.