RU2849083C1 - Composition of the binding agent solution for obtaining modified biochar - Google Patents

Abstract

FIELD: means for improving soil fertility.

SUBSTANCE: composition of the binder solution for obtaining modified biochar to improve soil fertility consists of the following components, wt. %: azophoska – from 5 to 30; urea – from 0.1 to 10; dextrin – from 6 to 20; water – the rest.

EFFECT: proposed composition of the binder solution for obtaining modified biochar provides modified biochar containing a set of microelements, with improved transportability, suitability for transportation, and high abrasion resistance.

1 cl, 1 tbl, 7 ex

Description

The invention relates to methods for producing modified biochar intended for improving soil fertility, namely to the composition of a solution for producing biochar with microelements phosphorus, potassium, calcium, magnesium, and sodium.

A method for granulating pyrocarbon coal with immobilized microorganisms and granules obtained by the said method is known [RU 2698659 C1, IPC C05G 5/00 (2006.01), C05G 3/00 (2006.01), C05F 3/00 (2006.01), publ. [28.08.2019], in which 1 kg of pyrocarbon with a moisture content of up to 5%, with an average linear particle size of pyrocarbon of no more than 2 mm ± 0.5 mm, is fed into the granulator. 500 ml of a plasticizer, which is an aqueous solution of LAYKSIL® 40-AL Silica Sol in a silica sol: water ratio of 4:1, is added per 1 kg of pyrocarbon with immobilized microorganisms. The granulation process is then carried out at a temperature of 40°C ± 10°C and atmospheric pressure to obtain the target product in the form of granules with a size of 4 mm. The granules are then dried at room temperature for 2 hours. Pyrochar granules have a macropore size of at least 5 µm, a specific surface area of at least 10 ^m2 /kg, a dry matter content of carbon of at least 40% by weight, nitrogen of at least 3.5% by weight, phosphorus of at least 1.5% by weight, potassium of at least 4% by weight.

The disadvantage of this method is the complexity and labor intensity of the technological process of obtaining the product.

An improved fertilizer is known [RU 2788485 C1, IPC C05F 1/00 (2006.01), C05G 1/00 (2006.01), publ. 20.01.2023], which is a solid fertilizer in the form of discrete particles, where each particle of the solid fertilizer contains an inorganic material containing at least one of the nutrients N, P, K or S, where the inorganic material is selected from one or more liquid and solid inorganic fertilizers, including ammonium sulfate, APP (ammonium polyphosphate), NPK (nitrogen, phosphorus, potassium), NO3PK, SOA (ammonium sulfate), MAP (monoammonium phosphate), DAP (diammonium phosphate), urea, CAN (calcium ammonium nitrate), MOP (potassium chloride), SOP (potassium sulfate), and heated organic material or torrefied organic material (a product with labile carbon from organic waste).

A disadvantage of this alternative is that the fertilizer is produced in discrete particles of varying sizes, which will lead to significant losses when applied in fields or open areas due to wind blowing. Furthermore, the fertilizer will wear down during transportation, leading to increased losses during application.

A known method for producing a pyrocarbon-based fertilizer containing the microelement iodine [RU 2720913 C1, IPC C05G 3/00 (2006.01), C05F 3/00 (2006.01), published 05/14/2020], selected as a prototype, consists of taking 10 mg of potassium iodide, dissolving it in 100 ml of distilled water, and also taking silica sol with a mass concentration of silicon dioxide of 39-41% and a micelle size of no more than 6 nm, mixing it with water in a ratio of 1 part silica sol to 3 parts water. Next, mix 100 ml of potassium iodide solution and 400 ml of silica sol solution. Then, take 1 kg of pyrocarbon charcoal and add 500 ml of the resulting aqueous solution of potassium iodide and silica sol. The pyrocarbon charcoal is then granulated, and the granules are maintained at 35°C for 4 hours.

The disadvantages of the prototype include the presence of only one microelement (iodine), which requires the addition of additional fertilizers to achieve high plant fertility, insufficient strength and effectiveness of use for its intended purpose.

The problem with known methods for producing biochar for improving soil fertility is that the resulting biochar loses its properties during transportation and handling. However, during transportation, it is necessary to preserve the complex properties that enable the biochar to be delivered to its destination in a usable form and used effectively for its intended purpose. The strength of modified biochar during transportation must meet the following requirements (GOST R 57016-2016): drop strength (SM) of at least 85%, and abrasion strength (DUr) of at least 80%. Biochar obtained using known methods does not possess the required properties, with drop strength less than 85% and abrasion strength less than 80%.

The technical result of the claimed invention is the production of modified biochar intended for improving soil fertility with microelements and improved transportability, suitability for the process of its transportation, movement while maintaining its properties.

By ensuring the mechanical strength of biochar granules against dropping of more than 85% and against abrasion of more than 80% during transportation, the integrity and structure of granules with microelements are maintained.

The technical result is achieved in that the composition of the solution of the binder for obtaining modified biochar for improving soil fertility consists of the following components, wt. %:

azofoska - from 5 to 30%;

urea - from 0.1 to 10%;

dextrin - from 6 to 20%;

water is the rest.

The drop strength of the resulting modified biochar is at least 85%, and the abrasion strength is at least 80%, which ensures the necessary conditions for transportation and use for its intended purpose with sufficient efficiency.

In the method for producing modified biochar for improving soil fertility, an aqueous solution of a binder containing azophoska, urea, dextrin is mixed with biochar, after which it is granulated, wherein the biochar is crushed to a size of less than 0.5 mm, the crushed biochar is mixed with the resulting solution of the binder in a given ratio, choosing the ratio of the solution of the binder and crushed biochar from 2 to 10 to 6 to 10, the resulting mixture is pressed at a pressure of 75 to 225 MPa and a temperature of 16 to 100 °C into granules or briquettes, which are dried at a temperature of 16 to 160 °C.

Implementation of the invention.

The method of obtaining biochar for improving soil fertility refers to the technology of obtaining granulated modified biochar.

Biochar is intended for use as a soil conditioner, soil improver, and ameliorant. It also functions as a fertilizer and can be used in agriculture and agro-industrial complexes. Adding modified biochar to soil improves its fertility and increases crop yields.

In the method for obtaining modified biochar for improving soil fertility, an aqueous solution of a binder containing azophoska, urea, dextrin is mixed with biochar, after which it is granulated, wherein the biochar is crushed to a size of less than 0.5 mm, at a temperature of 450 to 650 °C, the crushed biochar is mixed with the resulting solution of the binder in a given ratio, the optimal ratio of the solution of the binder and crushed biochar is from (2:10) to (6:10), the resulting mixture is pressed at a pressure of 75 to 225 MPa and a temperature of 16 to 100 °C into granules or briquettes, which are dried at a temperature of 16 to 160 °C.

The composition of the binder solution for obtaining modified biochar for improving soil fertility consists of the following components, wt. %:

azofoska - from 5 to 30%;

urea - from 0.1 to 10%;

dextrin - from 6 to 20%;

water is the rest.

The binder solution is obtained by adding the specified components to water in a given amount (% by weight).

They use biochar obtained through pyrolysis from manure, droppings, pine nut shells, and pine sawdust.

Biochar is crushed at a temperature of 450 to 650°C to a size of less than 0.5 mm and mixed with the resulting binder solution in a given ratio (for example 3:2), while the optimal ratio of the binder solution and crushed biochar is from (2:10) to (6:10).

The resulting mixture is pressed at a pressure of 75 to 225 MPa and a temperature of 16 to 100°C into granules or briquettes, which are dried at a temperature of 16 to 160°C.

The minimum pressing and drying temperature of 16°C was chosen based on the fact that the process is carried out in production facilities, the temperature inside which, according to SanPiN 1.2.3685-21 “Hygienic standards and requirements for ensuring the safety and (or) harmlessness of environmental factors for humans”, should not be less than 16°C.

Increasing the drying temperature above 160°C can lead to thermal destruction of dextrin [Fedoseyev S.D., Chernyshev A.B. Semi-coking and gasification of solid fuel. - Moscow: Gostoptekhizdat, 1960], which is a component of the binder solution, which will lead to the destruction of granulated biochar or its spontaneous combustion. As shown in the work [Tabakaev, R., Ibraeva, K., Astafev, A. et al. Pine nut shells of Siberian cedar as a resource for the high-strength smokeless fuel. Biomass Conv. Bioref. 14, 6737-6747 (2024). https://doi.org/10.1007/s13399-022-02820-7], using the example of obtaining smokeless fuel granules, an increase in the proportion of dextrin above 15% does not lead to an increase in the strength of the granules. At the same time, the cost of briquettes increases significantly.

The pressing temperature is 100°C or less; heating the pressed mixture of the binder solution and crushed biochar above 100°C is impractical, as it leads to evaporation of the binder solution and, as a consequence, will increase the cost of the resulting product.

The method ensures the production of biochar with sufficient strength (to abrasion and compression) for transportation while maintaining its properties, containing microelements (phosphorus, potassium, calcium, magnesium, sodium) that improve plant growth.

Microelements (mineral fertilizers: phosphorus, potassium, calcium, magnesium, sodium) are introduced into the composition of biochar granules at the stage of forming the binder solution - by introducing dextrin into water in an amount of 6 to 20%; as a rule, 12% by weight, taking into account permissible deviations.

The shedding strength (SM) of biochar is 85% or more, and the abrasion strength (DUr) is 80% or more.

Production of modified biochar intended for improving soil fertility with improved transportability, suitability for the process of its transportation, and movement while maintaining its properties.

Adding modified biochar, produced from manure with the addition of azophoska and urea, increases wheat yields by 311%. Adding modified biochar, produced from manure with the addition of azophoska and urea, increases wheat yields by 235%.

Table No. 1. Efficiency of biochar use.

No. Option Productivity, /ha Increase in control, % 1 Control 0.242 0 2 Granulated biochar from manure 0.813 235% 3 Granulated biochar from manure 0.995 311%

The amount of biochar applied to the soil is usually in the range from 10 to 30 t/ha [Tyurina E.A., Sviridov M.K., Nesterova O.V., Sakara N.A. Business model for the use of biochar by agricultural producers taking into account the concept of LCA (Life Cycle Assessment) and carbon footprint // Bulletin of the Far Eastern Federal University. Economics and Management. - 2022. - No. 4 (104). - P. 106-120; Popova A.D., Semal V.A., Brikmans A.V., Nesterova O.V., Kolesnikova Yu.A., Bovsun M.A. Use of biochar as an ameliorant and its impact on changes in the physical properties of agricultural soils in the south of Primorsky Krai // Bulletin of the Altai State Agrarian University. - 2019. - No. 6 (176). - P. 57-63.]. At the same time, on sod-podzolic soils, high agronomic efficiency as a soil ameliorator is achieved with the actual application of biochar at a dose of 10 t/ha [Ivanov A.I. Biochar in technologies for the development of bushy deposits // Proceedings of the international scientific seminar "Biochar: properties, application in agriculture, impact on soils, plants and the environment" FSBSI AFI, St. Petersburg, Russia, December 08, 2020. - P. 44-48].

Example 1.

Biochar obtained by pyrolysis of manure at 550°C is ground to a particle size of less than 0.5 mm. A binder solution is obtained by mixing the components in the following ratio:

Azofoska - 5%;

urea - 1.6%;

dextrin - 10.0%;

water - the rest up to 100%.

The binder solution is mixed with crushed biochar in a ratio of 5 to 10. The resulting mixture is pressed at a pressure of 150 MPa and a temperature of 20°C into cylindrical biochar granules measuring 15 mm × 10 mm, which are dried at a temperature of 60°C for 300 minutes in an ШС-160-02 drying oven. The mechanical strength of the resulting biochar granules upon dropping (SM) was 99.5%, the abrasion strength (DUr) was 93%. By ensuring the mechanical strength of the granules during transportation, the integrity and structure of the granules with microelements are preserved. After transportation, the biochar granules are added to the soil, which is located in a vegetation vessel with a cross-sectional area of 0.045 ^m2 , in the following proportion: 23 g of biochar granules per 2 kg of soil. Next, 10 seeds of the Novosibirskaya-31 spring wheat variety are planted in a growing vessel containing soil and biochar pellets. The yield of Novosibirskaya-31 soft spring wheat, when calculated per growing vessel area, is at least 0.81 t/ha.

The grain yield of soft spring wheat of the Novosibirskaya-31 variety under similar conditions without the addition of biochar granules, when recalculated per area of the vegetation vessel, is 0.25 t/ha.

Increasing the yield of spring wheat of the Novosibirskaya-31 variety by 235%.

Example 2.

Biochar obtained by pyrolysis of manure at 600°C is ground to a particle size of less than 0.5 mm. A binder solution is obtained by mixing the components in the following ratio:

Azofoska - 4.0%;

urea - 1.8%;

dextrin - 12.0%;

water - the rest up to 100%.

The binder solution is mixed with crushed biochar in a ratio of 6:10. The resulting mixture is pressed at a pressure of 75 MPa and a temperature of 40°C into cylindrical biochar granules measuring 15 mm × 10 mm, which are dried at a temperature of 100°C for 120 minutes in an ШС-160-02 drying oven. The mechanical strength of the resulting biochar granules upon dropping (SM) was 99.6%, the abrasion strength (DUr) was 80%. By ensuring the mechanical strength of the granules during transportation, the integrity and structure of the granules with microelements are preserved. After transportation, the biochar granules are added to the soil, which is located in a vegetation vessel with a cross-sectional area of 0.045 ^m2 , in the following proportion: 30 g of biochar granules per 2 kg of soil. Next, 10 seeds of the spring wheat variety "Novosibirskaya-31" are planted in a growing vessel with soil and biochar pellets. The yield of soft spring wheat of the "Novosibirskaya-31" variety in this case, when calculated per growing vessel area, is at least 0.99 t/ha.

The grain yield of soft spring wheat of the Novosibirskaya-31 variety under similar conditions without the addition of biochar granules, when recalculated per area of the vegetation vessel, is 0.25 t/ha.

Increasing the yield of spring wheat of the Novosibirskaya-31 variety by 311%.

Example 3.

Biochar obtained by pyrolysis of manure at 450°C is ground to a particle size of less than 0.5 mm. A binder solution is obtained by mixing the components in the following ratio:

Azofoska - 0.5%;

urea - 0.1%;

dextrin - 15%;

water - the rest up to 100%.

The binder solution is mixed with crushed biochar in a ratio of 4:10. The resulting mixture is pressed at a pressure of 120 MPa and a temperature of 60°C into cylindrical biochar granules measuring 15 mm × 10 mm, which are dried at a temperature of 160°C for 60 minutes in an ШС-160-02 drying oven. The mechanical strength of the resulting biochar granules upon dropping (SM) was 99.5%, the abrasion strength (DUr) was 95%. By ensuring the mechanical strength of the granules during transportation, the integrity and structure of the granules with microelements are preserved. After transportation, the biochar granules are added to the soil, which is located in a vegetation vessel with a cross-sectional area of 0.045 ^m2 , in the following proportion: 25 g of biochar granules per 2 kg of soil. Next, 10 seeds of the Novosibirskaya-31 spring wheat variety are planted in a growing vessel containing soil and biochar pellets. The yield of Novosibirskaya-31 soft spring wheat, when calculated per growing vessel area, is at least 0.27 t/ha.

The grain yield of soft spring wheat of the Novosibirskaya-31 variety under similar conditions without the addition of biochar granules, when recalculated per area of the vegetation vessel, is 0.25 t/ha.

The increase in yield is within the margin of error, indicating the ineffectiveness of applying biochar granules of this composition.

Example 4.

Biochar obtained by pyrolysis of litter at 650°C is ground to a particle size of less than 0.5 mm. A binder solution is obtained by mixing the components in the following ratio:

Azofoska - 30%;

urea - 20%;

dextrin - 20%;

water - the rest up to 100%.

The binder solution is mixed with crushed biochar in a 10:10 ratio. The resulting mixture is pressed at a pressure of 150 MPa and a temperature of 20°C into cylindrical biochar granules measuring 15 mm × 10 mm, which are then dried at a temperature of 100°C for 60 minutes in an ШС-160-02 drying oven. The mechanical strength of the resulting biochar granules in terms of shedding (SM) was 99.5%, and the abrasion resistance (DUr) was 89%. It is clearly visible that some of the binder is squeezed out of the mold, indicating an excessive amount of binder, which is economically impractical. The use of biochar granules of this composition is impractical in agricultural activities due to the high cost of production.

Example 5.

Biochar obtained by pyrolysis of pine nut shells at 600°C is ground to a particle size of less than 0.5 mm. A binder solution is obtained by mixing the components in the following ratio:

Azofoska - 4.3%;

urea - 1.7%;

dextrin - 6%;

water - the rest up to 100%.

The binder solution is mixed with crushed biochar at a ratio of 1:10. The resulting mixture is pressed at a pressure of 200 MPa and a temperature of 30°C into cylindrical biochar granules measuring 15 mm × 10 mm, which are then dried at 100°C for 60 minutes in an ШС-160-02 drying oven. The resulting biochar granules completely disintegrated during mechanical drop tests, indicating an insufficient amount of binder during their production.

Example 6. Biochar obtained by pyrolysis of pine nut shells at 500°C is ground to a particle size of less than 0.5 mm. A binder solution is obtained by mixing the components in the following ratio:

Azofoska - 4.3%;

urea - 1.7%;

dextrin - 12%;

water - the rest up to 100%.

The binder solution is mixed with crushed biochar in a ratio of 4:10. The resulting mixture is pressed at a pressure of 30 MPa and a temperature of 50°C into cylindrical biochar granules measuring 15 mm × 10 mm. Briquettes cannot be produced due to insufficient pressing pressure.

Example 7.

Biochar obtained by pyrolysis of pine sawdust at 500°C is ground to a particle size of less than 0.5 mm. A binder solution is prepared by mixing the components in the following ratio:

Azofoska - 4.0%;

urea - 5.0%;

dextrin - 8%;

water - the rest up to 100%.

The binder solution is mixed with crushed biochar in a ratio of 6:10. The resulting mixture is pressed at a pressure of 300 MPa and a temperature of 100°C into cylindrical biochar granules measuring 15 mm × 10 mm. Briquettes cannot be produced due to excessive pressing pressure, which causes the binder to be squeezed out of the mixture.

Claims (2)

The composition of the binder solution for obtaining modified biochar, consisting of the following components, wt. %: azophoska from 0.5 to 30 urea from 0.1 to 10 dextrin from 6 to 20 water rest