PL246909B1 - Granulate mixture of sawdust from coniferous wood and miscanthus enriched with a composition of additives - Google Patents

Abstract

The subject of the application is a granulate of a mixture of sawdust from coniferous wood and miscanthus, refined with a composition of additives reducing the level of emission of toxic exhaust components, containing iron(III) oxide and calcium oxide, characterized in that it consists of: 99% (m/m), calculated on the total mass of the granulate, of component I, in which from 49% to 51% (m/m) are sawdust from coniferous wood and from 49% to 51% (m/m) is miscanthus, and 1% (m/m), calculated on the total mass of the granulate, of component II, in which from 24.0% to 26.0% (m/m) is calcium oxide and from 74.0% to 76.0% (m/m) is iron(III) oxide, which components I and II are mixed and thoroughly homogenized before the granulation process.

Description

Description of the invention

FIELD OF TECHNOLOGY

The subject of the invention is a granulate of a mixture of sawdust from coniferous wood and miscanthus enriched with a composition of additives that reduces the level of emission of toxic exhaust components.

STATE OF TECHNOLOGY

Since the second half of the 1980s, regulations limiting the emission of harmful exhaust components into the atmosphere have been introduced and systematically tightened all over the world. The emission volume and type of exhaust components emitted from biomass-based energy facilities depend mainly on the fuel composition, the combustion process used and the exhaust gas cleaning method. Emissions of toxic exhaust components can also be limited by using substances dosed to the fuel at the stage of its production.

Patent description US 8048243 presents the composition of a universal additive for fossil fuels such as coal, crude oil, natural gas, and even for wood and charcoal, the use of which reduces the emission of sulfur oxides, nitrogen oxides and carbon monoxide. The additive consists of sodium nitrate in the amount of 12-18 wt.%, potassium permanganate 0.2-0.4 wt.%, sodium carbonate 0.5-1.5 wt.%, silicon dioxide 40-65 wt.%, iron(II) oxide 3-5 wt.%, magnesium oxide 2-5 wt.%, potassium oxide 0.3-0.8 wt.%, aluminum oxide 20-24 wt.% and iron(III) oxide 2.6-5.3 wt.%.

In order to reduce emissions of carbon monoxide, soot and particulate matter from the combustion of biomass, appropriate fuel additives are used, among others, to catalyze the combustion process. The authors of the papers (B. S. H. Kassmann, C. Andersson, J. Carlsson, U. Bjørklund, „Decreased emissions of CO and NOx by injection of ammonium sulphate into the combustion chamber”, Stockholm, 2005 and T. Streibel, F. Muhlberger, R. Geiβler, M. Saraji-Bozorgzad, T. Adam, and R. Zimmermann, „Influence of sulphur addition on emissions of polycyclic aromatic hydrocarbons during biomass combustion”, Proc. Combust. Inst., vol. 35, no. 2, pp. 1771-1777, 2015) presented the results of research in which they stated that the addition of ammonium sulphate reduces the emissions of polycyclic aromatic hydrocarbons, nitrogen oxides and carbon monoxide.

The authors of the research results published in the article (M. Gehrig, M. Wohler, S. Pelz, J. Steinbrink, and H. Thorwarth, "Kaolin as additive in wood pellet combustion with several mixtures of spruce and short-rotation-coppice willow and its influence on emissions and ashes", Fuel, vol. 235, pp. 610-616, 2019) found that kaolin is an effective agent for reducing carbon monoxide emissions generated during the combustion of fuel consisting of a mixture of energy willow and spruce. The addition of this mineral to the fuel reduced carbon monoxide emissions, depending on its concentration in the fuel and the composition of the biomass, from 23.8 to 68.4% compared to the fuel without the additive.

In the article (L. S. Bafver, M. Ronnback, B. Leckner, F. Claesson, and C. Tullin, "Particle emission from combustion of oat grain and its potential reduction by addition of limestone or kaolin", Fuel Process. Technol., vol. 90, no. 3, pp. 353-359, 2009) studies on the effectiveness of kaolin and limestone in reducing carbon monoxide emissions in the combustion process of oat grains were presented. The addition of 2% by mass of limestone reduced the emission compared to pure grain by 40%, while the addition of 2% by mass of kaolin by 66%, and the addition of 4% by mass of kaolin by 69%. Unfortunately, at the same time, the use of these minerals increased NOx emissions by 5%-32%, and SOx by 0.8%-19.7%.

The aim of the present invention is to obtain a granulate of a mixture of sawdust from coniferous wood and miscanthus, refined with a composition of additives limiting the level of emission of toxic components of exhaust gases emitted during the combustion process into the atmosphere, which will be characterized by a lower level of emission of organic carbon compounds, CO and SOx generated during its combustion than a granulate of a mixture of sawdust from coniferous wood and miscanthus not containing the additive composition.

It has been surprisingly found that such properties are possessed by the granulate of a mixture of sawdust from coniferous wood and miscanthus, refined with an additive composition, in accordance with the present invention, which is characterized by a lower level of emission of organic carbon compounds, CO and SOx generated during its combustion than the granulate of a mixture of sawdust from coniferous wood and miscanthus not containing the additive composition.

PL 246909 Β1

THE ESSENCE OF THE INVENTION

Granulate mixture of sawdust from coniferous wood and miscanthus, refined with a composition of additives reducing the level of emission of toxic exhaust components, containing iron(III) oxide and calcium oxide, is characterized by the fact that it contains:

- 99% (m/m), based on the total weight of the granulate, of component I, of which 49 to 51% (m/m) is coniferous wood sawdust and 49 to 51% (m/m) is miscanthus, and

1% (m/m), based on the total weight of the granulate, component II, of which from 24.0 to 26.0% (m/m) is calcium oxide and from 74.0 to 76.0% (m/m) is iron(III) oxide.

For the purposes of this invention, granulate should be understood as a product subjected to densification or compaction processes, including pellets and briquettes.

It turned out during the research that refining the granulate of a mixture of sawdust from coniferous wood and miscanthus with a composition of additives showing synergistic action allows for the reduction of the emission of organic carbon compounds from its combustion by over 99% and CO by approx. 95% in relation to the granulate of a mixture of sawdust from coniferous wood and miscanthus not containing the additive composition, as well as by approx. 83% in the case of OGC and by approx. 18% in the case of CO in relation to the granulate of a mixture of sawdust from coniferous wood and miscanthus containing iron(III) oxide used individually.

The present invention is presented in examples of embodiments 1 to 4, illustrating the composition, method of production and effectiveness of reducing the emission of toxic components of exhaust gases by using in the combustion process of granulate of a mixture of sawdust from coniferous wood and miscanthus refined with an additive composition in test trials, therefore they cannot be considered as limiting the essence of the invention, because they are only illustrative. Examples 1 and 2 are comparative examples, and examples 3 and 4 are examples of the invention.

EXAMPLES

Example 1 - comparative example

5000 g of coniferous wood sawdust with properties given in Table 1 and 5000 g of miscanthus with properties given in Table 2 were weighed, then the components were thoroughly mixed and the mixture was granulated in a ZLSP-150B pelleting machine by Haven Polska Sp. z o.o. using a matrix with a mesh diameter of 6 mm.

Table 1

Characteristics of coniferous wood sawdust used for research

Xn7v-.i u^nat /. ·ηι and iii-4od and I am examining... Unit Value Total moisture content % 11.2 Ash content % 0.3 Combustion heat kj/kg 18918 Calorific value kj/kg 16560 Elemental carbon content % 46.7 Hydrogen content % 5.65

PL 246909 Β1

Table 2

Characteristics of the Miscanthus used for the study

Name of designation, test method Total moisture content Unit % Value 11.9 Ash content % 1,2 Combustion heat kj/kg 18252 Calorific value kJ/kg 15731 Elemental carbon content % 45.4 Hydrogen content % 5.47

Example 2 - comparative example

4950 g of coniferous wood sawdust with properties given in Table 1, 4950 g of miscanthus with properties given in Table 2 and 100 g of iron(III) oxide with properties given in Table 3 were weighed, combined and thoroughly mixed. The sample with the mixed sawdust, miscanthus and iron(III) oxide was then granulated in a ZLSP-150B pelleting machine by Haven Polska Sp. z o.o. using a matrix with a mesh diameter of 6 mm.

Table 3

Characteristics of iron(III) oxide used for testing

λ,ΡΜ n/łld /eiua melKil.l bdd il M -Unit Value FezOa Contents % 96.0 pH (5% suspension), 20°C 5 Density kg/ ^dm3 5.24 Bulk density kg/ ^dm3 0.7

Example 3

4975 g of coniferous wood sawdust with properties from Table 1, 4925 g of miscanthus with properties from Table 2 were weighed, combined and thoroughly mixed. 75 grams of iron(III) oxide with properties from Table 3 and 25 g of calcium oxide with properties from Table 4 were weighed, combined and thoroughly mixed. The mixed coniferous wood sawdust and miscanthus were mixed with a composition of additives: iron(III) oxide and calcium oxide and thoroughly mixed. The obtained sample was granulated in a ZLSP-150B pelleting device from Haven Polska Sp. z o.o. using a matrix with a mesh diameter of 6 mm.

PL 246909 Β1

Table 4

Characteristics of calcium oxide used for testing

Name of the marking, test method Unit Wart ort· CaO content % 92.2 MgO content % 2.0 Reactivity of co Γ57” Bulk density kg/ ^dm3 0.952

Example 4

Combustion tests of the products from examples 1 to 3 were carried out in a pellet fireplace stove model AIRPELL 8 by Defro with a nominal thermal power of 8 kW.

During the tests, measurements of the content of carbon monoxide (II) and organic carbon compounds in the exhaust gases were taken. The exhaust gases intended for the analysis of the content of harmful substances were taken from the nozzles installed in the measuring section connecting the heater with the chimney flue. The MRU ECU 3000 gas analyser was used to test the content of carbon monoxide (II), while the Thermo-FID TG gas analyser was used to test the content of organic carbon compounds. The measurement of carbon monoxide (II) was carried out in accordance with the PN-EN 14785:2009 standard (Pellet-fired space heaters - Requirements and test methods). The measurement of organic carbon compounds was carried out in accordance with the PN-EN 303-5:2012 standard (Heating boilers. Part 5: Heating boilers for solid fuels with manual and automatic fuel charging with a nominal output of up to 500 kW - Terminology, requirements, testing and marking). The determined results of the 25-minute average CO and organic carbon content emitted during combustion of the products from Examples 1 to 3 are presented in Table 5.

In accordance with the requirements of the PN-EN 14785:2009 standard and the COMMISSION REGULATION (EU) 2015/1185 of 24 April 2015 implementing Directive 2009/125/EC of the European Parliament and of the Council with regard to requirements for solid fuel local space heaters, the measured substance values in the flue gases were converted to 13% oxygen content.

Table 5

CO and organic carbon content emitted during combustion of products from examples 1 to 3

Exhaust gas component [unit] CO recalculated [pplll] OGC converted [πΐ^/ΐΐΐ^] Product from example 1 (comparative) 2555.0 167.5 Product from example 2 (comparative) 157.0 4.6 Product from example 3 129.0 0.8

The above examples demonstrate the effect of the additive composition according to the invention on reducing the level of CO emissions and organic carbon compounds emitted during the combustion of granulated biomass fuels and prove its industrial applicability.

Claims (1)

1. Granulate of a mixture of sawdust from coniferous wood and miscanthus, refined with a composition of additives reducing the level of emission of toxic exhaust components, containing iron(III) oxide and calcium oxide, characterized in that it comprises: - 99% (m/m), based on the total mass of granulate, component I, in which from 49 to 51% (m/m) is coniferous wood sawdust, and from 49 to 51% (m/m) is miscanthus, and - 1% (m/m), based on the total mass of granulate, component II, in which from 24.0 to 26.0% (m/m) is calcium oxide, and from 74.0 to 76.0% (m/m) is iron(III) oxide.