RU2782019C1 - Pellets from compressed biomass - Google Patents

Abstract

FIELD: fuel pellets.

SUBSTANCE: invention relates to fuel pellets. A pellet made of pressed biomass is proposed, which includes dried spent coffee grounds and a binder, additionally contains paper waste, and sugar syrup is used as a binder in the following ratio, wt.%: coffee grounds 93.75-90.25; waste paper and cardboard 6-9; sugar syrup - the rest.

EFFECT: development of non-wood pellets from biomass with high thermal conductivity.

1 cl, 9 tbl, 16 ex

Description

The invention relates to compositions intended for the preparation of biofuel pellets for various types of power plants.

Known solid fuel composition (Canada patent No. 2378098, publ. 07/13/2010), used for the manufacture of artificial briquettes, which by weight contains from 1 to 50% coffee waste, from 10 to 50% sawdust and from 30% to 65% of fuel wax. The coffee grounds component has a moisture content of 15% to 80% by weight, with a particle size of at least 0.5 mm.

The disadvantage of this composition is the use of paraffin wax as a binder component, since its combustion releases harmful components, such as toluene and benzene.

A wax-free briquette is known (US patent No. 8439988, publ. 05/14/2013), consisting of a core made of dried waste coffee grounds, vegetable fat, brown sugar and corn syrup, as well as an outer shell made of paper strips, while neither the core, nor the outer shell, does not contain wax. Dried spent coffee grounds is 54 wt. %, vegetable fat is 23 wt.%, brown sugar is 20 wt.%, corn syrup is 2 wt.%.

The disadvantage of this composition is the additional preparation of ingredients, which consists in mixing vegetable fat and brown sugar and bringing to a boil with constant control of burning and harmful emissions from the combustion of sugars.

Non-wood pellets from pressed biomass are known (patent of the World Intellectual Property Organization No. 2011/020190 A1, publ. 24.02.2011), made in the form of a composite composition of wax, one dry material containing cellulose, and at least one non-dry material with a moisture content not less than 15%. Dry material can be represented by cardboard, wax, waste paper, dry green residues, sawdust and wood residues - soft and hard wood trimmings and wood waste. Non-dry material is wet waste such as paper, corn stalks, coffee grounds, Christmas trees and flower waste. The components are interconnected by a binder based on water-soluble starch (1-3 wt.%). The water-soluble starch may be in the form of corn starch, rice starch, or mixtures thereof.

The disadvantage of this composition is the multicomponent and variability of the composition, which cannot provide stable fuel characteristics, as well as the unpredictable and uncontrolled formation of combustion by-products of the composition.

Biomass fuel is known (US patent No. 2011/0119996A1, publ. 05/26/2011), consisting of consisting of combustible biomass and an adhesive additive containing starch and various types of hydroxides (alkali metal hydroxide, alkaline earth metal hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, lithium hydroxide or caustic soda). It is proposed to use duckweed, rice husks, coal dust, sawdust, cardboard, grasses, weeds, pine cones, newsprint, food industry waste, paper waste, pallets and egg cartons as biomass. The composition contains by weight 69-98% biomass, 1-30% starch and less than 1% hydroxide.

The disadvantage is the multicomponent and variability of the composition, which cannot provide stable fuel characteristics, as well as the unpredictable and uncontrolled formation of combustion by-products of the composition. Also, the inclusion of alkali and alkaline earth metal hydroxides in the composition will lead to a rapid failure of the internal lining of the boiler unit.

Known solid fuel composition (US patent No. 5910454, publ. 06/08/1999), which contains more than 70 wt. % dried waste coffee grounds and up to 25 wt. % solid combustible binder - wax based on paraffin, and the coffee grounds contain less than 20% moisture, the particle size is less than 2 mm.

A combustible biofuel composition from biomass is known (patent of the World Intellectual Property Organization No. 2017/093757 Al, publ. 06/08/2017), taken as a prototype, which is pellets or briquettes and contains at least 75% of used coffee grounds and less than 50% of fuel filler. The filler is selected from sawdust, barley waste, hop waste, cocoa husk, sugar beet, straw, wood, nut husk, cane, grain waste, corn, wheat straw and barley straw. Additionally contains a binding agent - polysaccharide, glycerin, paraffin, vegetable oil, lignosulfonate or molasses.

The disadvantages are also the multicomponent and variability of the composition, which cannot provide stable fuel characteristics, as well as the unpredictable and uncontrolled formation of combustion by-products of the composition, as well as the release of harmful components during combustion - toluene and benzene, if paraffin is used as a binder.

The technical result is the development of non-wood pellets from biomass with high thermal conductivity.

The technical result is achieved by additionally containing paper waste, and sugar syrup is used as a binder in the following ratio of components, wt. %:

coffee grounds 93.75 - 90.25; paper and cardboard waste 6-9; sugar syrup rest.

The claimed pellet from pressed biomass includes the following reagents and commercial products containing them, % wt.:

- coffee grounds from 93.75 to 90.25 obtained in the process of brewing natural roasted coffee in accordance with GOST R 52088-2003 Natural roasted coffee. General technical conditions;

- paper and cardboard waste from 6 to 9, produced in accordance with GOST R 52901-2007 Corrugated cardboard for product packaging and GOST R 57641-2017. Xerographic paper for office equipment. General technical conditions;

- sugar syrup 0.25-0.75 produced in accordance with GOST 28499-2014 Syrups. General specifications.

Coffee grounds are obtained as a homogeneous mixture from espresso brewing, filter coffee brewing, cold brew, French press or coffee brewing in dishes in the food industry and in households and are dried and used. On average, spent coffee grounds contain 57±5% carbon, 8±3% hydrogen, 2±1% nitrogen, 0.3±0.1% sulfur and 1.8% ash elements (potassium, magnesium, phosphorus, calcium, silicon and etc.). Dried spent coffee grounds are dried using a warm air flow in a vortex tube created by a compressor or blower. The moisture content of the dried waste grounds is controlled and is less than 8%.

Shredded paper and cardboard waste without impregnation and coating, uncontaminated (FKKO code 40510000000), belonging to hazard class V, and sugar syrup are used as a structure-forming component. Paper and cardboard waste is generated as a result of unpacking raw materials, materials and equipment from cardboard containers and in the course of clerical activities and office work. They consist of cellulose or waste paper, sizing agents and mineral fillers.

As a binder, sugar syrup is used for the preparation of coffee drinks in the food industry and in households. Expired sugar syrup may also be used in the composition.

As evidence of the effectiveness of the use of pellets from compressed biomass and obtaining comparative data on the characteristics of pellets from compressed biomass, samples were prepared from the proposed raw mixture.

Paper and cardboard waste is shredded in a shredder or crusher to a particle size of no more than 5 mm.

Dried waste coffee grounds and shredded paper and cardboard waste are mixed in a bulk mixer or grinder. Additionally, sugar syrup is added to the mixer using a dispersing type dispenser.

The resulting raw material mixture is pressed into the form of pellets from compressed biomass using a press using a granulator for feed and pellets ZL. Laboratory studies are possible using a hand press Carver 4350 L with a press force of at least 3 tons.

The composition is illustrated by the following examples.

Example 1. To obtain a raw mixture, 98.75 g of dried waste coffee grounds, 1 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.25 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 2. To obtain a raw mixture, 93.75 g of dried waste coffee grounds, 6 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.25 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 3. To obtain a raw mixture, 90.75 g of dried waste coffee grounds, 9 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.25 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 4. To obtain a raw mixture, 89.75 g of dried waste coffee grounds, 10 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.25 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 5. To obtain a raw mixture, 98.5 g of dried waste coffee grounds, 1 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.5 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 6. To obtain a raw mixture, 93.5 g of dried waste coffee grounds, 6 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.5 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 7. To obtain a raw mixture, 90.5 g of dried waste coffee grounds, 9 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.5 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 8. To obtain a raw mixture, 89.5 g of dried waste coffee grounds, 10 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.5 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 9. To obtain a raw mixture, 98.25 g of dried waste coffee grounds, 1 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.75 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 10. To obtain a raw mixture, 93.25 g of dried waste coffee grounds, 6 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.75 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 11. To obtain a raw mixture, 90.25 g of dried waste coffee grounds, 9 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.75 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 12. To obtain a raw mixture, 89.25 g of dried waste coffee grounds, 10 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 0.75 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 13. To obtain a raw mixture, 98 g of dried waste coffee grounds, 1 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 1 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 14. To obtain a raw mixture, 93 g of dried waste coffee grounds, 6 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 1 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 15. To obtain a raw mixture, 90 g of dried waste coffee grounds, 9 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 1 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Example 16. To obtain a raw mixture, 89 g of dried waste coffee grounds, 10 g of crushed waste paper and cardboard without impregnation and coating, uncontaminated, and 1 g of sugar syrup were taken. Pellets from compressed biomass with a diameter of 15 mm and a length of 14 mm were pressed from the obtained raw mixture using a Carver 4350 L manual press with a press force of 3 tons (table 1).

Table 1 - Options for the composition of the raw mixture for the production of pellets

№№ Coffee grounds Waste paper and cardboard without impregnation and coating, uncontaminated syrup sugar The total amount of the mixture Weight, g wt.% Weight, g wt.% Weight, g wt.% Weight, g wt.% one 98.75 98.75 one one 0.25 0.25 100 100 2 93.75 93.75 6 6 0.25 0.25 100 100 3 90.75 90.75 9 9 0.25 0.25 100 100 four 89.75 89.75 ten ten 0.25 0.25 100 100 5 98.5 98.5 one one 0.5 0.5 100 100 6 93.5 93.5 6 6 0.5 0.5 100 100 7 90.5 90.5 9 9 0.5 0.5 100 100 eight 89.5 89.5 ten ten 0.5 0.5 100 100 9 98.25 98.25 one one 0.75 0.75 100 100 ten 93.25 93.25 6 6 0.75 0.75 100 100 eleven 90.25 90.25 9 9 0.75 0.75 100 100 12 89.25 89.25 ten ten 0.75 0.75 100 100 13 98 98 one one one one 100 100 fourteen 93 93 6 6 one one 100 100 fifteen 90 90 9 9 one one 100 100 16 89 89 ten ten one one 100 100

To confirm the possibility of beneficial use of pellets from compressed biomass, an assessment was made of compliance with the requirements for regulatory and reference documentation for solid biofuels.

Humidity was determined using an ANDMX-50 moisture analyzer in accordance with GOST 32975.3 - 2014. Ash content and the yield of volatile substances were measured in a LECO TGA-701 thermogravimetric analyzer in accordance with GOST 32988 - 2014 and GOST 32990 - 2014, respectively. Mechanical strength was measured using an apparatus for testing pellets in accordance with GOST 34090.2 - 2017 (Tables 2-5).

Table 2 - Results of testing the physical and mechanical properties of pellets from pressed biomass

Share of binding components syrup sugar 0.25% Waste paper and cardboard one% 6% 9% ten% Coffee grounds rest rest rest rest Humidity, % 5.54 5.35 5.21 6.72 Ash content, % 2.02 1.83 2.13 2.5 Volatiles, % 79.66 80.02 80.42 81.13 Mechanical strength, % 90.1 89.4 91.5 94.7

Table 3 - Results of testing the physical and mechanical properties of pellets from pressed biomass

Share of binding components syrup sugar 0.5% Waste paper and cardboard one% 6% 9% ten% Coffee grounds rest rest rest rest Humidity, % 5.72 5.28 5.4 6.89 Ash content, % 1.98 1.97 2.14 2.32 Volatiles, % 79.74 79.94 80.04 80.73 Mechanical strength, % 96.2 93.4 92.7 98.6

Table 4 - Results of testing the physical and mechanical properties of pellets from pressed biomass

Share of binding components syrup sugar 0.75% Waste paper and cardboard one% 6% 9% ten% Coffee grounds rest rest rest rest Humidity, % 5.83 5.3 5.79 6.98 Ash content, % 1.59 2.31 2.47 2.14 Volatiles, % 81.48 79.26 81.84 80.02 Mechanical strength, % 95.5 92.9 94.2 97.3

Table 5 - Results of testing the physical and mechanical properties of pellets from pressed biomass

Share of binding components syrup sugar one% Waste paper and cardboard one% 6% 9% ten% Coffee grounds rest rest rest rest Humidity, % 5.97 5.55 6.14 6.76 Ash content, % 2.4 1.99 2.21 2.58 Volatiles, % 81.37 80.66 81.47 80.25 Mechanical strength, % 93.5 93.1 93.8 96.4

Combustion of pellets from pressed biomass was carried out in the LECO CHN-628S analyzer furnace, the resulting exhaust gases were identified using the ECOLAB gas analyzer equipped with sensors for measuring the concentrations of carbon monoxide, methane, ammonia, hydrogen sulfide, nitrogen monoxide, nitrogen dioxide and aliphatic limiting hydrocarbons (С1-С10 ). The higher specific heat of combustion was measured by combustion in an IKA C 2000 calorimeter in accordance with GOST 33106 - 2014.

The test results for burning pellets are presented in tables 6-9. The content of shredded waste paper and cardboard from 5 to 10 wt. %, sugar syrup from 0.25 to 0.75 wt. %, dried waste coffee grounds - the rest is the most suitable for the formation of pellets: when the content of waste paper and cardboard is less than 5%, it is difficult to achieve homogeneity of the raw mixture, and when the content of waste paper and cardboard is more than 10%, the value of the highest specific heat of combustion of pellets drops significantly. The content of sugar syrup less than 0.25% reduces the effect of pellet binding, the content of sugar syrup more than 0.75% is excessive.

Table 6 - Results of testing the properties of pellets from compressed biomass during combustion

Portion of binder syrup sugar 0.25% Waste paper and cardboard one% 6% 9% ten% Coffee grounds rest rest rest rest Higher specific heat of combustion, MJ/kg 23.65 23.25 22.29 24.59 CO ₂ , mg/g 138.59 141.05 158.38 166.23 CO, mg/g 0.23 0.24 0.20 0.23 NO, mg/g 0.59 0.62 0.63 0.60 NO ₂ , mg/g 0.23 0.22 0.23 0.24

Table 7 - Results of testing the properties of pellets from compressed biomass during combustion

Portion of binder syrup sugar 0.5% Waste paper and cardboard one% 6% 9% ten% Coffee grounds rest rest rest rest Higher specific heat of combustion, MJ/kg 24.04 23.99 23.62 23.3 CO ₂ , mg/g 142.15 144.23 156.44 164.81 CO, mg/g 0.21 0.21 0.21 0.23 NO, mg/g 0.58 0.58 0.6 0.61 NO ₂ , mg/g 0.21 0.22 0.22 0.24

Table 8 - Results of testing the properties of pellets from compressed biomass during combustion

Portion of binder syrup sugar 0.75% Waste paper and cardboard one% 6% 9% ten% Coffee grounds rest rest rest rest Higher specific heat of combustion, MJ/kg 24.50 23.57 24.28 23.13 CO ₂ , mg/g 144.97 143.63 154.64 166.37 CO, mg/g 0.2 0.23 0.2 0.22 NO, mg/g 0.54 0.59 0.62 0.58 NO ₂ , mg/g 0.22 0.22 0.21 0.23

Table 9 - Results of testing the properties of pellets from compressed biomass during combustion

Portion of binder syrup sugar one% Waste paper and cardboard one% 6% 9% ten% Coffee grounds rest rest rest rest Higher specific heat of combustion, MJ/kg 22.24 22.35 23.85 23.63 CO ₂ , mg/g 150.35 148.96 157.74 162.57 CO, mg/g 0.24 0.23 0.22 0.23 NO, mg/g 0.53 0.54 0.58 0.62 NO ₂ , mg/g 0.19 0.21 0.23 0.22

According to the results of tests of samples of pellets from pressed biomass, a classification was assigned according to the following parameters: origin - 3, fruit biomass; diameter D, mm - D12, D = (12±1.0) mm, length L = 3.15mm<L≤50 mm, moisture content, M - M08, ≤8%, ash content, A - A3.0, ≤ 3.0%, mechanical strength, DU - DU95.0-92.0, <95.0%, volatile matter, VM - 81%.

The offered biomass pellets allow to reduce the consumption of wood and traditional fuels. Another advantage when using pellets from pressed biomass is the useful disposal of waste by involving it in economic circulation with the prospect of using it in various types of power plants: pellet boilers, fireplaces for space heating, in field conditions, etc.

Claims (2)

Compressed biomass pellet, including dried waste coffee grounds and a binder, characterized in that it additionally contains paper waste, and sugar syrup is used as a binder in the following ratio, wt.%: coffee grounds 93.75 - 90.25 paper and cardboard waste 6-9 sugar syrup rest