The invention relates to a method of combusting coal solid fuels, an additive to coal solid fuels and a method of manufacturing the additive to coal solid fuels.

Currently, despite numerous attempts to shift energy-consuming economy to electric energy obtained from renewable sources which do not contaminate the natural environment, a significant share of energy in industrialized countries still comes from traditional power plants based on the combustion of solid fuels, especially coal. Despite a relatively careful selection of fuels in terms of the possibility of reducing harmful products of combustion and flue gas treatment systems used and the utilization of combustion products, traditional combustion of solid fuels, especially coal fuels, results in an extremely high emission of gas products harmful to the environment such as nitrogen oxides, sulfur dioxide and high volumes of carbon monoxide and dioxide.

Growth of the so-called „ozone hole" in the upper layers of the Earth's atmosphere corresponding to increase in air pollution, and rapid and observable climate changes caused by this phenomenon, as well as natural disasters caused by these changes, force us to look for solutions to improve the efficiency of the combustion of solid fuels and reduce resulting emissions of unfavorable products. Russian patent document RU2437028 (Cl) discloses a method of intensifying the process of burning solid low-reaction fuel in thermal power plants including preparation of pulverized-coal mixture of low-reactivity fuel with air and nanoaddition; pulverized-coal mixture is subject to ultrasonic treatment immediately prior to supply to burners, and then to ignition and burning in the boiler. Astralines - multi-layer fulleroide nanoparticles or Taunit - carbon nanomaterial are used as nanoadditions. Nanoadditions are introduced to pulverized-coal mixture in the form of homoeopathic doses as per weight of solid fuel of 0.01 - 0.02%. The method results in increase of response rate of ignition and combustion of fuel mixture; besides, at combined burning of low-reactivity coal and fuel oil in the steam boiler furnace the method leads to reduction of unburnt carbon, nitrogen and sulfur oxides emissions, and therefore, to reduction of corrosion of heating surface and to improvement of reliability of power equipment; increase in combustion efficiency of pulverized-fuel mixture of low-reactivity fuel with air and nanoaddition owing to avoiding the agglomeration of components.

American patent US6250235 (Bl) discloses a method of treating a fossil fuel for combustion and an additive in a combustion zone. The additive contains a lime flux that lowers the melting point of said lime sufficiently so that said lime in the combustion zone melts wholly or partially. The additive reacts with the fossil fuel char and its sulfur plus ash components, in the combustion zone to achieve the following results alone or in combination: accelerated combustion, desulphurization, nitrogen oxides emission reduction, pozzolanic or cementitious product production or combustor anti-fouling.

Korean patent description KR102172020 (Bl) discloses additives to solid fuel and a method of manufacturing additives to solid fuel. A solid fuel additive is a solid fuel additive formed by mixing and stirring a natural powder and dehydration cake treated organic waste, wherein the natural powder contains peat moss, a red clay powder, activated carbon, and zeolite. According to the invention, it is possible to provide the solid fuel additive used for manufacturing eco-friendly solid fuel exhibiting a high calorific value, and a method for manufacturing the solid fuel additive.

Russian patent document RU2707276 (Cl) discloses a preparation method of pulverized coal fuel for combustion. The document describes a method for preparation of pulverized coal fuel for combustion, which consists in drying and crushing crude coal, wherein said coal is coated with oxides and/or hydroxides of iron in the form of a suspension or dry powder spray, wherein concentration (amount) of deposited iron oxides and/or iron hydroxides should not exceed 0.4 % of the weight of the coal. Iron oxides and/or hydroxides are also applied on coal in the form of suspension in modified liquid glass, in which they make not more than 5 %. The invention facilitates reduction of average time of release of volatile substances, increase of rate of coagulation of magnetic particles, reduction of slagging of walls of boilers due to introduction of additive from iron oxides on surface of dust particles in a hammer coal mill, and also reduction of emission of ash aerosols into atmosphere.

Japanese patent application JPH02169910 (A) discloses a burning method of solid fuel in which to prevent the sticking of solid fuel in the handling device, improve the pulverization efficiency and control the secondary granulation by adding a certain type of surface active agent of anion group at the time of burning solid fuels such as coal, oil coke, etc. which contains alkylether sulfate with alkyl group chosen from a mixture of oil and fat such as palm oil, cattle oil, sperm oil, etc. and synthetic alcohol, in form of potassium salt, sodium salt, ammonium compounds or alkanolamine such as mono, di or triethanolamine. The solid fuel additive of surface active agent is added to the solid fuel by spraying, etc. as is or in the form of a solution at any point from the receiving of solid fuel prior to the pulverizer. The amount of the additive to be used is 100 to 10,000ppm relative to the solid fuel, and is changed according to the kind of solid fuel, moisture content, etc.

German patent application DE19504190 (Al) discloses an additive for promoting combustion of solid fuel which contains at least one: magnesium derivative, ammonium derivative, potassium derivative, sodium derivative and/or a metal salt, characterized in that it additionally contains 3% to 60%, preferably 5% to 40%, based on the total weight of the additive, of a non-ionic surfactant or a mixture of non-ionic surfactants. The non-ionic surfactant or the mixture thereof comprises non-ionic surfactants based on fatty acids, fatty amines, fatty alcohols, nonylphenols and polyalkylene glycols.

Chinese patent application CN104745268 (A) discloses solid fuel and preparation method thereof. The solid fuel is prepared from the following raw materials in percentage by weight: 20-40% of a dehydrated sludge cake, 0.5-5% of lime powder, 30-65% of clay and 10-30% of an additive, wherein the water content of the dehydrated sludge cake is 80-90%, the granularity of the lime powder is 20- 80 meshes, and the additive can be pulverized coal, coal slime, fire coal cinder or coal gangue powder. In addition, the invention further provides a preparation method of the solid fuel. The solid fuel disclosed by the invention takes the dehydrated sludge cake as a main raw material, and the preparation method is simple, can be put into industrialization easily, is capable of well disposing residual activated sludge, digested sludge, mixed sludge and the like generated by municipal sewage treatment plants, is beneficial to reduction treatment and resource utilization of sludge; the combustion heat value of the solid fuel is 5-15MJ/kg, and the solid fuel can be used in production of building materials of tiles, ceramsites, floor tiles and the like and as an internal combustion doping fuel.

Chinese patent application CN102786999 (A) discloses a solid fuel modification additive, which comprises the following ingredients in percentage by mass: 0.1 to 99.8 percent of silicon dioxide, 0.1 to 99.8 percent of aluminum oxide, 0.01 to 50 percent of titanium dioxide and 0.01 to 5 percent of copper compounds, wherein the copper compounds refer to compounds containing copper ions. Modification compounds and compounds for improving the ash melting point are added into fuel according to different proportions, the melting point of products including ash, slag and the like generated after the fuel combustion is improved, meanwhile, the crystallization form is changed, the coking and contamination of molten combustion products in the high-temperature combustion process of the fuel at a furnace hearth and a heating surface can be effectively relieved and avoided, meanwhile, the ash slag structures become porous, crystal, loose and fragile, and the clearing is convenient.

Czech patent document CZ295617 (B6) discloses an additive of solid fossil fuel combustion process and method for stabilizing combustion process by making use of such additive. The invention discloses an additive of solid fossil fuel combustion process comprising meat and bone meal being optionally added with a trace of up to 0.5 percent of an ingredient formed by a mixture consisting of 15 to 48 percent by weight of ferrous sulfate, 2 to 35 percent by weight of noble metal nitrates and the remainder up to 100 percent by weight being water. The additive is added in a solid fossil fuel before combustion thereof in an amount of a trace ranging up to 11 percent by weight of fossil fuel whereupon it is burned off in the fireplace. The additive contains meat-and-bone meal with a calorific value greater than 18 MJ/kg with a volatile combustible content greater than 60% by weight; a carbon content of more than 30% by weight and a water content of up to 3.5% by weight, and additionally contains up to 0.5% of an additive consisting of 15 to 48% by weight of ferrous sulphate, 2 to 35% by weight of rare earth nitrates and the remainder being water up to 100% by weight. The additive is added to the solid fossil fuel in the range of up to 11% by weight of the fossil fuel before combustion, and then burnt together in the furnace.

Polish patent application PL 194593 discloses environment friendly solid fuel briquettes containing fine coal and/or fine brown coal and/or coke and/or sawdust and/ or peat and/or straw and binder i.e. collagen obtained preferably from natural tanned and/or untanned animal skins; wherein the collagen content ranges from 0.25-25 parts by weight based on dry weight. Chromium (III) contained in the amount of up to 5% by weight in tanned skins has catalytic properties during the combustion at temperatures above 700 °C and burns soot and other harmful organic substances to carbon dioxide and water.

In the state of the art, there are known methods of reducing the emission of harmful gas products of solid fuel combustion consisting in the use of mineral additives which contain metal ions which have an observable beneficial impact on the fuel combustion process, and reduce the content of harmful gas components of combustion products.

In practice, it was also found that the ash structure depends on the method of solid fuel combustion. The phase composition of coal ash can be divided into a glassy and a crystalline phase. Microscope examinations show that the ashes produced as a result of the known, traditional combustion of coal consist mainly of crumbs and dark-colored lumps of irregular shape and structure. Large amounts of unburnt carbon particles are also observed in the ashes. Light grains, made of sand or clay admixtures of coal, occur in smaller amounts.

During the conducted research and operational experiments on the combustion of hard coal and brown coal in the presence of iron (III) and copper (II) ions, it unexpectedly turned out that permanent introduction to the coal fuel of even a small amount of an additive containing iron (III) and copper (II) ions in an appropriate mutual proportion has a positive and significant impact on the emission volume of gases such as: CO ₂ , NOx and SO ₂ .

For the purpose of this invention, the term coal solid fuel is understood as hard coal and brown coal and their blends.

In the method of combusting coal solid fuels according to the invention, an additive in an amount from 0.1 - to 0.2% by weight consisting of an aqueous solution, containing iron ions Fe ⁺³ in the amount of 10 to 100 g/l and copper ions Cu ⁺² in the amount of 10 to 50 g/l and non-ionic surfactants in an amount of up to 1% by weight wherein the mutual weight ratio of iron ions Fe ⁺³ to copper ions Cu ⁺² ranges from 0.4 to 2.2, is added to coal solid fuel of the granulation of 5-25mm and water content of up to 15 % by weight. The additive is added to the solid fuel in an amount of 1 to 2 liters per 1 ton of fuel.

Preferably, the source of iron ions is iron (III) chloride FeCI ₃ and the source of copper ions is copper (II) sulfate CUSO ₄ . Research conducted on the impact of iron ions Fe ⁺³ bound as FeCI ₃ and copper (II) sulfate Cu ⁺² confirmed beneficial effect of these salts on the emission volume of gases such as carbon dioxide CO ₂ , nitrogen oxides NO _X and sulfur dioxide SO ₂ .

It was found that iron chloride FeCl ₃ in combination with copper sulfate CuSO ₄ turned out to be a valuable and effective additive to solid fuels which increases the oxidation degree of the burnt fuel and reduces the formation of harmful gaseous combustion products. At a temperature of about 200°C, carbon reduces the iron ions Fe ⁺³ contained in iron (III) salts to atomic iron, which is very reactive. It ignites spontaneously on contact with air. Combustion of this iron results in the formation of iron oxides, which at higher temperatures in contact with carbon (C) reduce back to metallic metal. This cycle continues until the carbon and/or oxygen and/or the products of combustion in the form of carbon dioxide CO ₂ , carbon monoxide CO and water H ₂ O are exhausted.

It was also found that copper ions Cu ⁺² , if used in an appropriate amount, have an activating effect and cause an increase in the combustion temperature at which the degree of combustion of solid coal fuel goes up and post-combustion of coal increases which in turn directly increases the energy efficiency of the furnace.

One of the most important reactions in the process is the reaction between iron and water. Hydrogen (H) is formed in the process. Hydrogen reacts with carbon dioxide CO2 to produce carbon monoxide CO and water H ₂ O.

In turn, iron Fe reacts with water to produce iron(lll) oxide, and carbon monoxide CO reacts with the resulting iron oxides. The reactions continue until one of the substrates is exhausted. The surfactant contained in the additive preferably improves the wettability of fuel grains and even distribution of the additive according to the invention in the fuel mass which in consequence increases the degree of combustion of coal solid fuel in its total mass.

The invention also relates to an additive to coal solid fuels which is an aqueous solution containing iron ions Fe ⁺³ in the amount of 10 to 100 g/l and copper ions Cu ⁺² in the amount of 10 to 50 g/l and at least one non-ionic surfactant in the amount of up to 1% by weight, wherein the mutual weight ratio of Fe ⁺³ ions to Cu ⁺² ions is in the range from 0.4 to 2.2.

Preferably, the additive according to the invention contains iron (III) chloride FeCI ₃ as the source of iron ions Fe ⁺³ and copper (II) sulfate CuCl ₂ as the source of copper ions Cu ⁺² .

The additive according to the invention is preferably added to a coal solid fuel in the amount of 1.0 do 2.0 liter per 1 ton of fuel.

The invention also relates to a method of obtaining the additive to coal solid fuels. In the method of obtaining the additive to solid coal fuels at least one iron salt Fe ⁺³ and at least one copper salt Cu ⁺² is dissolved in water or in an aqueous solution in such an amount that in the final solution obtained the content of iron ions Fe * ³ ranges from 10 to 100g/l and the content of copper ions Cu ⁺² ranges from 10 to 50g/l, and the mutual weight ratio of Fe ⁺³ ions to Cu ⁺² ions falls within the range of 0.4 to 2.2, and at least one non-ionic surfactant in the amount of up to 1% by weight. Preferably, the source of iron ions is iron (I II ) chloride FeCl ₃ and the source of copper ions is copper (II) sulfate CuSO ₄ .

The subject of the invention is presented in the following embodiments.

Table no. 1 shows, by way of example, chemical compositions of the additive according to the invention (content of mineral components in an aqueous solution, in % by weight) .

Table No. 1

The according to the invention is an aqueous solution obtained by mixing iron(lll) chloride FeCl ₃ and copper (If) sulfate CuSO ₄ FeCl ₃ and CuSO ₄ , regardless of the percentage composition, is brownish grey.

Example 1

In a laboratory vessel at room temperature, a 7% solution of iron chloride Fe ⁺³ was prepared by dissolving 7 g of iron chloride FeCI ₃ in 93 g of water, and then 5 g of copper sulphate CuSO ₄ was added to the obtained solution. 0.5% by weight of nonionic surfactants was added to the obtained solution and carefully mixed. The so obtained additive according to the invention in the amount of 20 ml was mixed in a laboratory mixer with coal solid fuel in the amount of 10 kg i.e. hard coal in form of fine coal, containing 0.8% of sulfur, and then the obtained coal solid fuel according to the invention was burnt in an experimental furnace equipped with a set of temperature sensors, flue gas analyzer and a calorimeter to perform qualitative and quantitative (volumetric) measurements of emitted products of combustion and heat.

A comparative blank test without the additive according to the invention was performed in parallel.

Results are shown in table no. 2.

Table no. 2 Example 2.

A 7% iron chloride solution was prepared in a mixer of the volume of 5 m ³ equipped with a rotary paddle mixer by dissolving iron chloride FeCl ₃ in 3,5 m ³ of water, and 175 kg of copper sulphate CuSO ₄ was added. 0.8 % by weight of nonionic surfactants was then added to the obtained solution and the whole content was carefully mixed. The so obtained additive to coal solid fuels according to the invention was mixed with coal solid fuel in form of fine coal, granulation 5-25 mm, containing 0.8% of sulfur S. The additive according to the invention was applied to the surface of transported coal in the amount of 1.67 I / 1000 kg by means of directly spraying the conveyor belt with fine coal and then components of the coal solid fuel according to the invention were carefully mixed when the fuel was poured into a bunker and the obtained coal solid fuel according to the invention was fed to the furnace to be burnt. During the combustion process, a continuous measurement of the flue gas composition was carried out using a flue gas analyzer provided by the heating plant, which continuously measures CO _2; SO ₂ , NO _X .

In parallel, a comparative blank test of fine coal alone was carried out under identical conditions but without the additive to coal solid fuel according to the invention.

Results of measurements from example 2 were compared in table 3 Table no. 3

Emission of gases resulting from the combustion of coal fuel using the method according to the invention decreased respectively: CO ₂ - by 46%, NOx - by 40%,

SO ₂ - by 88% - against the comparative blank test where fine coal without the additive according to the invention was used.

Example 3

In a laboratory vessel at room temperature, a 5% solution of iron chloride Fe ⁺³ was prepared by dissolving 5g of iron chloride FeCl ₃ in 95g of water, and then 3g of copper sulphate CuSO ₄ was added to the obtained solution. 0.5% by weight of non- ionic surfactants was then added to the obtained solution and carefully mixed. The so obtained additive according to the invention in the amount of 20 ml was mixed in a laboratory mixer with coal solid fuel in the amount of 10 kg i.e. brown coal in form of fine coal containing 2.8% of sulfur, and then the obtained coal solid fuel according to the invention was burnt in an experimental furnace equipped with a set of temperature sensors, flue gas analyzer and a calorimeter to perform qualitative and quantitative measurements of emitted gas products of combustion and heat.

A comparative test without the additive according to the invention was performed in parallel.

Results are shown in table no. 4.

Table no. 4 Coal solid fuel burnt using the method according to the invention containing the addition according to the invention shows, among others, decreased emission of carbon dioxide, nitrogen oxides and sulfur dioxide as confirmed by tests.

It was also found that the use of the additive to coal solid fuels according to the invention and burning it in fine hard coal, granulation 5-25mm, leads to an increase in the heating value by from 0.98 MJ/kg to 1.27Mj/kg, which makes it possible to estimate the increase in the heating value following the use of the liquid by 3.5% on average, and also decreases the volume of residue in form of ash by from 4% to 5% against the comparative test which makes it possible to estimate average decrease of ash volume by approx. 14% against the comparative test. Combustion of coal solid fuels using the method according to the invention which contain the additive to solid coal fuels according to the invention reduces the level of sulfur dioxide in the emitted flue gas by from 18% to 88% against the comparative test.

Experiment no. 1.

In order to evaluate the form, composition and structure of solid fuel combustion products using the method according to the invention, ashes obtained in both cases according to example no. 2 were subjected to SEM analysis. The analysis was conducted using a scanning electron microscope Tescan Vega 3 SBU (Tescan, Brno, Czech Republic) with a WDS / EDS analyzer, and comparing the obtained images. Experiment no. 2.

To assess the impact of the additive according to the invention on the surface of the furnace structure, the additive according to the invention was mixed with fine coal and a piece of steel being a combination of boiler steel P265GH and stainless steel EN1.4306 and roasted in a laboratory muffle furnace, porcelain crucible for 60 minutes at 800°C, steel samples were taken out after cooling down, cleaned from ash remains and scanned using SEM microscope (Fig7). The evaluation was performed using SEM analysis. The tests were performed using the Tescan Vega 3 SBU scanning electron microscope (Tescan, Brno, Czech Republic), magnification (lOOx). The microscope analysis showed that standard steel and stainless steel behave in a similar way and the content of the additive according to the invention in coal solid fuel burnt using the method according to the invention has no impact on the steel surface.

Results obtained were presented in the accompanying illustrative material, where:

Fig. 1 shows changes in the concentration of carbon dioxide CO ₂ in flue gas during combustion in example 1 for the real test (solid line) and for the comparative blank test (broken line).

Fig. 2 shows changes in the concentration of sulfur dioxide SO ₂ in flue gas during combustion in example 2 for the real test (solid line) and for the comparative blank test (broken line). Fig. 3 shows changes in the concentration of nitrogen oxides NO _X in flue gas during combustion in example 2 for the real test (solid line) and for the blank test (comparative).

Fig. 4 shows a magnified image of ash resulting from burning coal without the additive according to the invention [SEM image, magnification (100x)]

Fig. 5 shows a magnified image of ash resulting from burning coal with the additive according to the invention [SEM image, magnification (100x)]

Fig. 6 shows an image of a magnified selected area of the surface of an ash sample subjected to EDS analysis for ash resulting from the combustion using the method according to the invention of coal solid fuel in form of hard coal used in example 2 with the additive to coal solid fuels [magnification (100x)], whereas

Fig. 7 shows a SEM image of a magnified piece of a furnace structure made of standard steel and stainless steel from example 2 after the combustion of coal solid fuel using the method according to the invention - containing the additive according to the invention, roasted at 800 °C for 60 min [magnification (100x)] .

Following a SEM analysis of ashes generated in both cases from example 2, grains of special characteristics, the so-called spherical grains (microspheres) were found in furnace waste resulting from the combustion of coal containing the additive according to the invention. The coating of these grains is tight, glassy, milky or colorless. Microspheres are a valuable product of the combustion of coal solid fuels and are used in industry, among others, in the production of light mineral thermal insulation materials. A significant reduction was observed in the volume of unburnt carbon particles in the furnace waste resulting from the combustion of coal solid fuels containing the additive according to the invention.

The spectroscopic analysis performed using the EDS method [Energy Dispersive Spectroscopy], indicates a low content of sulfur and iron in the microareas in the tested ash samples resulting from combustion of coal without the additive according to the invention. Elemental analysis shows the presence of a large amount of silicates, aluminosilicates and carbon in ash. It is also confirmed by SEM images which show a large amount of unburnt carbon particles.

The additive according to the invention has a big impact on changes in the morphological structure of ash and its elemental composition. The EDS analysis in micro-areas indicates an increased iron content in ash and the formation of structures containing sulfur and iron compounds.

In the analyzed areas, especially in the area marked with a circle, the occurrence of an irregular lump of ash consisting mainly of sulfur and iron can be observed, probably in the form of iron sulphide with an undetermined chemical composition, or iron sulphate after oxidation.

The method of combusting coal solid fuels according to the invention causes the reaction of sulfur contained in the ash with iron ions contained in the additive according to the invention, causing the formation of, inter alia, iron sulphide. Such observations are confirmed by the analysis of the composition of flue gases and a reduction of sulfur dioxide SO ₂ content in flue gas. In turn, the reduced amount of NO _X nitrogen oxides in the gas combustion products is due to the favorable chemical composition of the additive according to the invention and its reducing properties, resulting in the reduction of nitrogen oxides NO _X to free nitrogen N ₂ .

The conducted research showed that the used additive according to the invention does not have adverse destructive effects on the furnace interior material during the combustion of fine coal fuel using the method according to the invention, containing the additive according to the invention. The effect of the additive according to the invention on boiler steel P265GH and stainless steel EN1.4306 was also analyzed. The analysis of microscope images of both steels at lOOx magnification showed that the additive according to the invention damaged the surface of boiler steel P265GH during 24 hours-etching period at room temperature, while it had little or no effect on the surface of stainless steel EN1.4306.

The method of burning coal solid fuels containing the additive according to the invention shows a reduction of the emission of carbon dioxide, nitrogen oxides and sulfur dioxide.

The use of the additive to coal solid fuels according to the invention and its combustion in fine hard coal and fine brown coal, granulation 5-25mm, increases heating value by from 0.98 MJ/kg to 1.27Mj/kg, which results in an increase in the heating value by an average of 3.5% after using the additive according to the invention.

The use of the additive to coal solid fuels according to the invention in form of fine hard coal and fine brown coal and burning it using the method according to the invention results in a reduction of the volume of solid combustion residue in form of ash by from 4% to 5% which makes it possible to estimate average decrease of ash volume by ca. 14% against the test without the use of the invention.

The additive to solid coal fuels according to the invention reduces the volume of sulfur dioxide SO ₂ in emitted flue gas by from 18% to 88% as compared to flue gas emitted using the known method of combustion i.e. without the additive according to the invention.

The use of the additive to solid coal fuels according to the invention makes it possible to increase heat efficiency and decrease the volume of coal solid fuels burnt using the method according to the invention by ca. 15% as compared to the volume of coal solid fuels which do not contain the additive according to the invention, necessary to obtain the same thermal power. Thus, the use of the combustion method according to the invention and the additive according to the invention allows for significant economic savings related to the consumption of raw material - coal fuel used for combustion. The method of burning coal solid fuels according to the invention makes it possible to reduce the volume of solid residues of the combustion process in form of ash by 14%. Furthermore, the combustion method according to the invention makes it possible to increase the use of the heating value of coal solid fuel by ca. 4%, which in turn makes it possible to increase the efficiency of power equipment.

The use of the additive to coal solid fuels according to the invention makes it possible to significantly reduce the emission of all harmful gas products of burning coal solid fuels thus creating great opportunities and prospects for its use in the heating and energy industry.

The method and the additive according to the invention may also be used in industrial and municipal waste incineration plants.

The use of the additive according to the invention for the combustion of fine coal using the method according to the invention in households using class 3 central heating boilers increases heating value by from 0.36 MJ/kg to 0.82Mj/kg, which makes it possible to estimate the increase in the heating value resulting from the use of the additive according to the invention by 1.5-2.5% on average

The use of the additive according to the invention in households results in a better combustion of coal (greater use of the heating value), reduction in the amount of ash produced and a reduction in the emission of harmful gases into the atmosphere. The use of the additive to coal solid fuels according to the invention causes longer retention and afterburning of heat and improves the thermal efficiency of a heating system through better combustion of coal/fine coal. It has been estimated that burning coal solid fuels in households using the method according to the invention reduces coal consumption by approx 0.1-0.15 ton per year which reduces the use of coal solid fuel in a household by 15-20 %.