The present invention is related to a stabilized combustion modifier of the FBC (Fuel Born Catalyst) type of high efficiency for light heating oils, improving combustion of coal particles and hydrocarbons, the use of which reduces the emission of environmentally harmful substances, particularly of solid particles and nanoparticles.

Starting from the second half of the eighties of the last century, regulations limiting the emission of harmful components of exhaust fumes to the atmosphere, including the emission of particulate matter (PM), have been introduced and systematically tightened all over the world.

The use of additives of the FBC type to upgrade light heating oil reduces the amount of toxic components of exhaust fumes.

The mechanism of oxidation of the organic components of exhaust gases using catalysts of the FBC type is a very complex and not fully understood process. According to one of the recognized hypotheses, in the first step of oxidation reaction, the nanoparticles of a metal oxide are probably adsorbed on the surface of soot particles. Subsequently, at the exhaust gas temperature, a redox reaction takes place, wherein carbon is oxidized to carbon monoxide, and the metal is reduced to its lower oxidation state. The next step is the reaction of oxidation of carbon(II) monoxide to carbon(IV) oxide. Due to the lower stability of metals at a lower degree of oxidation at the exhaust gas temperature, their rapid reoxidation takes place. The reactions occurring during soot oxidation are exothermic reactions and occur in a heterogeneous solid-gas system.

In the process of soot oxidation, additives containing metallic compounds (mainly oxides), in which these metals can occur in numerous oxidation states, are primarily applied. Compounds composed of elements of this type have the ability to form composite complex systems, which is particularly important in the case of additives which modify the combustion process.

In the context of in-situ transformation of FBC catalysts to their catalytic fluidized active form, the impact of the chemical structure of the applied dispersant on the efficiency of FBC catalyst in the process of coal and hydrocarbon particles combustion is important. U.S. Patent No. 4920061 discloses a process for preparing paramagnetic colloidal compounds containing magnetite (FeO Fe ₂ 0 ₃ ) or cobalt compounds, in which oleic acid was used to prevent particle aggregation and precipitate formation.

In turn, US Patent No. 6271269 and U.S. Patent Application No. 2009/0156439 disclose a process for preparing stable sols containing colloidal dispersion of at least one metallic compound, for example cerium(IV) and/or iron(III) in the organic phase, which comprises an organic liquid medium and an organic acid, which may be one of the following compounds: fatty acids of tall oil, coconut oil, soybean oil, linseed oil, oleic acid, linoleic acid, stearic acid, isostearic acid, pelargonic acid, capric acid, lauric acid, myristic acid, dodecylbenzenosulfonic acid, 2-ethylhexanoic acid, naphthenic acid, hexanoic acid, toluenesulfonic acid, toleuenephosphonic acid, laurylsulfonic acid, laurylphosphonic acid, palmitylsulphonic acid and palmitylphosphonic acid.

Further, in U.S. Patent Applications No. 2010/0242342 and No. 2013/0197107, a process for preparing nanoparticles of cerium or other metal oxides, stabilized with higher carboxylic acids such as oleic, linoleic, palmitic or stearic acid, used as additives for hydrocarbon fuels, was described.

In turn, U.S. Patent Application No. 2006/0000140 discloses a package of additives for diesel fuel containing iron and cerium oxides stabilized with fatty acids, particularly with oleic acid, or a mixture thereof.

Polish Patent No. 198569 discloses a process for preparing complex organosoluble salts of trivalent iron, applied as modifiers of the combustion process of hydrocarbon fuels, using isooctadecanoic acid in a hydrocarbon solvent.

Patent Application No. WO/2008/116552 discloses a process for preparing colloidal iron oxides in a carrier liquid ensuring excellent colloid properties, which is a mixture of mono- and polycarboxylic acids containing from 8 to 20 carbon atoms in their chain. The described process has an advantage which allows for maintaining the desired physical form of iron oxide particles, and hence all its characteristics (e.g. crystal form or magnetic properties).

A similar process for preparing colloidal cerium and iron oxides is disclosed in Patent Application No. WO/2013/116647. Also in this case, carboxylic acids, such as caprylic acid and enanthic acid, were used as dispersion stabilizers for metal oxides.

U.S. Patent No. 2010/0300079 discloses that an additive, which is an organic dispersion of iron and cerium compounds and amphiphilic compounds, such as organic acids having a number of carbon atoms from 15 to 25, lowers the flash point of soot accumulated on the particulate filter in the diesel engine.

U.S. Patent No. 5562742 discloses the use of organometallic complexes of metals such as Na, K, Mg, Ca, Sr, Ba, V, Cr, Mo, Fe, Co, Zn, B, Pb, Sb, Ti, Mn and Zr and mixtures of these metals using carboxylic acids, such as stearic, oleic, lauric, linoleic acids, as soot combustion catalysts.

Further, U.S. Patent Application No. 7459484 discloses a process for preparing a colloidal dispersion of iron compounds, characterized in that it consists of an organic phase, particles of iron compounds in an amorphous form and at least one amphiphilic compound. It is produced in a process in which either an iron salt in the presence of a complexing substance or an iron complex is subjected to a reaction with a base to obtain a precipitate, and the precipitate or a suspension containing the said precipitate is brought into contact with the organic phase in the presence of an amphiphilic compound until a dispersion in the organic phase is obtained. As amphiphilic compounds, carboxylic acids having a number of carbon atoms from 10 to 50 were applied. The described dispersion can be applied as an additive for combustion of liquid hydrocarbon fuels.

U.S. Patent No. 8147568 discloses a process for producing diesel oil containing a colloidal metallic catalyst for soot afterburning. The said catalyst comprises compounds or complexes of manganese, sodium, platinum or iron, stabilized using carboxylic acids, such as lauric acid, myristic acid, palmitic acid, palmitoleic acid, stearic acid, oleic acid, elaidic acid, ricinoleic acid, linoleic acid, linolenic acid, eicosanoic acid, gadoleic acid, docosanoic acid or erucic acid.

Following presented literature data different kinds of solutions are used to ensure the proper dissolution and/or dispersion of substances, which are precursors of FBC catalysis, thereby preventing precipitation, separation or turbidization of said precursors in solvents and hydrocarbon fuels.

The aim of the invention is to provide a stabilized combustion modifier of an FBC (Fuel Born Catalyst) type of high efficiency for light heating oils, forming stable solutions and/or dispersions in solvents and hydrocarbon fuels, improving the combustion of carbonaceous particles and hydrocarbons, the use of which will reduce the emission of harmful substances, in particular solid particles and nanoparticles, into the environment. Surprisingly, it has been found that these properties are characteristic for an stabilized combustion modifier of high efficiency for light heating fuels, according to the present invention, containing substances ensuring proper dispersion of FBC catalysts precursors in solvents and hydrocarbon fuels, improving the combustion of carbonaceous particles and hydrocarbons, and reducing the emission of environmentally harmful substances, in particular solid particles and nanoparticles.

The stabilized combustion modifier of high efficiency for light heating fuels, improving the combustion of carbonaceous particles and hydrocarbons, comprises FBC catalysts precursors, soluble or dispersible in organic liquid, according to the present invention, contains from 5.0% (w/w) to 60.0% (w/w), preferably from 25.0% (m/m) to 35.0% (m/m) fully and without limitations, FBC catalysts precursors, soluble or dispersible in light heating fuels in the form of complexed non-stoichiometric nano-oxides and/or nano-hydroxides and/or nano- oxyhydroxides of iron, preferably of trivalent iron, containing from 5 to 30% (w/w) of iron in a complex compound, an organic dispersant being a mixture of aliphatic and/or aromatic mono- and/or dicarboxylic acids, having a number of carbon atoms in molecules from 4 to 24, preferably from 10 to 22, and possibly esters and/or semi-esters being derivatives of mono- and/or dicarboxylic acids, having a number of carbon atoms in molecules from 4 to 24, preferably from 10 to 22, and linear or cyclic mono- and/or polyhydroxylic alcohols, having a number of carbon atoms in molecules from 1 to 9, preferably from 2 to 5, and a content of hydroxyl groups in molecules from 1 to 4, preferably from 1 to 2, and/or amides and/or imides and/or amidoimides being derivatives of mono- and/or dicarboxylic acids, having a number of carbon atoms in molecules from 4 to 24, preferably from 10 to 22, and amines or aliphatic polyamines, having a content of nitrogen atoms in molecules from 1 to 6, preferably from 2 to 4, and/or hydroxyamides and/or hydroxyimides, being derivatives of mono- and/or dicarboxylic acids, having a number of carbon atoms in molecules from 4 to 24, preferably from 10 to 22, and aminoalcohols, having a content of hydroxyl groups in molecules from 1 to 4, preferably from 1 to 2, and a content of nitrogen atoms in molecules from 1 to 6, preferably from 2 to 4, in an amount from 1.0% (w/w) to 30.0% (w/w), preferably from 5.0% (w/w) to 20.0% (w/w), and an organic solvent in an amount from 5.0% (w/w) to 80.0% (w/w), preferably from 10.0% (w/w) to 65.0 (w/w), being a hydrocarbon solvent of a boiling point up to 220°C under normal conditions or a linear and/or branched aliphatic alcohol, having a number of carbon atoms in molecules from 8 to 13 or an ether or a polyether or etheralcohol, being a derivative of monoalcohol and an ether or a polyether of alkylphenol or mixtures thereof.

It has been found that, the interacting FBC catalysts precursors and organic dispersants used in the above-mentioned formulation create a synergistic system which reduces the flash point of soot up to 40% compared to other known FBC additives.

The invention is further explained by the following embodiments from 1 to 10, presenting the composition of the additive of an FBC (Fuel Born Catalyst) type of high efficiency for light heating oils and the assessment of selected properties of this additive based on laboratory and bench tests. However, it is understandable that these examples cannot be treated as limiting the invention, as they are of a purely illustrative nature.

Example 1

30 g of hydrated iron(II) sulfate and 45 g of hydrated iron(III) sulfate and 150 ml of water were introduced into a reactor equipped with a reflux condenser, anchor stirrer, heating system and dropping funnel. The contents were stirred at room temperature until complete dissolution of the salts. Subsequently, the contents of the reactor were heated to a temperature of 60°C at simultaneous stirring, and once the temperature was fixed, 15% of ammonia solution was added dropwise until the pH reached 7.5. The resulting aqueous suspension of insoluble iron compounds was subjected to further processing.

Example 2

A mixture consisting of 16.4 g of 10-undecylenic acid, 105.0 g of toluene and 90.0 g of aliphatic petroleum fraction boiling in the range of 180-210°C was added to the aqueous suspension of Example 1. The contents of the reaction mixture were heated to a temperature of 70°C at continuous stirring, and this temperature was maintained for 5 hours. At this time, the reaction mixture was transferred into a separatory funnel, and the aqueous layer was separated from the organic layer containing a mixture of compounds of bivalent and trivalent iron. The raw organic fraction was introduced into a reactor equipped with a reflux condenser, anchor stirrer, heating system and dropping funnel. The fraction was heated to a temperature of 60°C, and subsequently, under vigorous stirring, 200.0 g of hydrogen peroxide at a concentration of 3.0% was added dropwise. After completion of the dropwise addition, the content of the reactor was maintained at a temperature of 70°C and stirred for 1 hour. It was then introduced into a separatory funnel, and water was separated from the organic layer. The organic fraction was subjected to azeotropic distillation of water, and the residue was filtered. In the resulting product, iron content was determined using the ICP AES method. The results are shown in Table 1.

Example 3

17.0 g of a mixture consisting of oleic and 10-undecylenic acid, 105.0 g of toluene and 90.0 g of aliphatic petroleum fraction boiling in the range of 180-210°C was added to the aqueous suspension of Example 1. The contents of the reaction mixture were heated to a temperature of 70°C at continuous stirring, and this temperature was maintained for 5 hours. At this time, the reaction mixture was transferred into a separatory funnel, and the aqueous layer was separated from the organic layer containing a mixture of compounds of bivalent and trivalent iron. The raw organic fraction was introduced into a reactor equipped with a reflux condenser, anchor stirrer, heating system and dropping funnel. The fraction was heated to a temperature of 60°C, and subsequently, under vigorous stirring, 200.0 g of hydrogen peroxide at a concentration of 3.0% was added dropwise. After completion of the dropwise addition, the content of the reactor was maintained at a temperature of 70°C and stirred for 1 hour. It was then introduced into a separatory funnel, and water was separated from the organic layer. The organic fraction was subjected to azeotropic distillation of water, and the residue was filtered. In the resulting product, iron content was determined using the ICP AES method. The results are shown in Table 1.

Example 4

A mixture consisting of 11.6 g of oleic acid, 105.0 g of toluene and 90.0 g of aliphatic petroleum fraction boiling in the range of 180-210°C was added to the aqueous suspension of Example 1. The contents of the reaction mixture were heated to a temperature of 70°C at continuous stirring, and this temperature was maintained for 5 hours. At this time, the reaction mixture was transferred into a separatory funnel, and the aqueous layer was separated from the organic layer containing a mixture of compounds of bivalent and trivalent iron. The raw organic fraction was introduced into a reactor equipped with a reflux condenser, anchor stirrer, heating system and dropping funnel. The fraction was heated to a temperature of 40°C, and subsequently, under vigorous stirring, 200.0 g of hydrogen peroxide at a concentration of 3.0% was added dropwise. After completion of the dropwise addition, the content of the reactor was maintained at a temperature of 70°C and stirred for 1 hour. It was then introduced into a separatory funnel, and water was separated from the organic layer. The organic fraction was subjected to azeotropic distillation of water, and the residue was filtered. In the resulting product, iron content was determined using the ICP AES method. The results are shown in Table 1.

Table 1

Iron content in the products

Example 5

The hydrodynamic diameters of particles in the products of Examples 2, 3 and 4 were determined using the photon correlation spectroscopy method according to PN-ISO 13321. In the test, a Zetasizer Nano S particle size analyzer provided by Malvern was used. In this method, the size of nanoparticles is determined based on the measurement of the speed of Brownian motion of molecules contained in the test sample. The results are shown in Table 2.

Table 2

Hydrodynamic diameters of the products

Example 6

The product of Example 2 was introduced into a light heating oil of the characteristics presented in Table 3 at such an amount that the concentration of iron in oil was 20 mg/kg. Table 3

Characteristics of light heating oil

Example 7

The product of Example 3 was introduced into a light heating oil of the characteristics presented in Table 3 at such an amount that the concentration of iron in oil was 20 mg/kg.

Example 8

The product of Example 4 was introduced into a light heating oil of the characteristics presented in Table 3 at such an amount that the concentration of iron in oil was 20 mg/kg.

Example 9

The stability of the products obtained according to Examples 2, 3, 4 and the products introduced into light heating oil according to Examples 6, 7, 8 was determined based on the method developed at the Oil and Gas Institute - National Research Institute. According to said method, test samples of additives are stored at 40°C for a period of 14 days, while additives introduced into the fuel at 80°C for a period of 14 days. At specific time intervals, the samples are subjected to visual assessment. The criterion of stability of test substances is lack of delamination and lack of sediments. The results are shown in Table 4. Table 4

The results of stability tests of the products

Example 10

The products of Examples 2, 3, 4 were subjected to thermo-programmed tests of soot oxidation. In the test, 8 mg of powdered soot samples mixed with the products of Examples 2, 3, 4 (the ratio of soot to iron ions was 5: 1) were applied. The test samples were placed in a thermogravimetric and calorimetric flow reactor installed in an oven, the temperature of which was raised at a rate of 10°C/min up to 700°C. During the test, a gas mixture consisting of 14% (V/V) 0 ₂ and 86% (V/V) Ar was passed through the reactor at a rate of 60 ml/min. The progress of the reaction was monitored by changing the weight of the sample and the signal associated with the heat transfer caused by an exothermic reaction of soot oxidation. As characteristic temperatures of this reaction, the temperature of initiation and the temperature of termination of the oxidation reaction were determined.

Based on the conducted tests, in the accompanying drawing, plots of the dependency of the intensity of heat transfer from the test samples, caused by an exothermic reaction of soot oxidation on the temperature in the reactor, were presented. Changes in signal intensity for the product of Example 2 were indicated by a dotted line, for the product of Example 4, by a dashed line, and for the product of Example 3, by a solid line. The product of Example 3 (solid line) is characterized by higher catalytic activity, as both the initiation and termination of soot oxidation processes take place at lower temperatures than for the products of Examples 2 and 4.