EP3325581B1

EP3325581B1 - Ecological solid fuel additive, reducing soot formation

Info

Publication number: EP3325581B1
Application number: EP15787013.0A
Authority: EP
Inventors: Dariusz LATOWSKI; Marek CHYC; Edeltrauda HELIOS-RYBICKA
Original assignee: Uniwersytet Jagiellonski
Current assignee: Uniwersytet Jagiellonski
Priority date: 2015-07-23
Filing date: 2015-09-23
Publication date: 2020-01-29
Anticipated expiration: 2035-09-23
Also published as: PL231237B1; WO2017013476A1; PL413233A1; EP3325581A1

Description

The subject-matter of the invention is the ecological solid fuel additive, reducing soot formation. The fuel additive for soot combustion applied in operations of hard coal, lignite, fine coal, coke, anthracite, peat, pellets, coal briquettes and wood-burning furnaces as well as low, medium and high efficiency furnaces and boilers.
To this moment, the fuel additives, chemical composition of which could produce corrosion of steel and ceramic components of the heating installation or contribute to increased release of toxic pollutants formed in the combustion process, have been used.
There are certain fuel additives containing the mixtures of inorganic and organic soils, primarily chlorides and transition metal compounds, for the most copper, known.
The effective fuel additive allowing for reduction by deposit volume at the exchanger by 45-55% is known from the Chinese patent CN 1010483 . The fuel additive is a mixture of potassium nitrate (60-80%), ammonium nitrate, triiron tetroxide (0.1-1.0%), charcoal, borax, trisodium phosphate as chelating agent, magnesium, aluminum, sodium chloride and powdered sulphur. The additive is used in household and industrial installations and industrial coal-burning boilers. The additive modifies chemical and physical soot properties improving at the same time heating efficiency of the heat exchanger. The fuel additive is decomposable in 485°C, forming a coating on the heat exchanger surface and protecting it against corrosion. Coal additive to coal of low calorific value known from the Chinese CN 103305313 patent description contains 20-100% of active substance. Mixture of active substances contains 30-80% in weight of calcium cobaltite (Ca₃Co₄O₉), 0-30% in weight of triiron tetroxide (Fe₃O₄) and cerium dioxide (CeO₂) and potassium oxide of several percents in weight. The fuel additive revealed in this invention decreases the fuel ignition temperature by 3-15°C, enhancing the combustion effectiveness and making coal combustion with fuel additive less polluting to the air comparing to fuel combustion without the fuel additive.
The soot combustion catalysts containing copper sulphate, sodium chloride and ammonium chloride are known from PL 207482 and PL 165406 patent description. Despite its advantages in combustion of lesser quantities of coal and lower risk of carbon deposities ignition in the flue pipes, this is not environmentally safe operation.
The ecological aquous liquid fuel additive containing among others hydrated fusel oils and ethyl alcohol is known from Polish patent PL 202335 .
The solid biomass additive containing among others the carboxylic acid salts and one or more metals from among the alkaline earth, lanthanide and ferrous metals; fatty acid esters and fatty acids or acidic resins, is known from the EP 0 725 128 B1 patent. The fatty acid esters are, advantageously, methyl esters, in particulars of rape oil esters. The described additive enhances mechanical properties of biomass in the course of processing and reduces production of toxic fumes. The disadvantage of the described solution is no opportunity to apply the additive to any other fuels than pulverized one.
US 2011/155028 discloses a combustion catalyst for enhancing the combustion of solid fuels such as coal and reducing slagging, fouling and carbon emissions. The described combustion catalyst contains: sodium nitrate, ferrous oxide (FeO), Fe₂O₃ (iron oxide), sodium carbonate, potassium permanganate (KMnO₄) and clay mineral (montmorillonite, providing silicon dioxide, MgO, CaO, Al₂O₃). In high power installations described in US 2011/155028 the iron oxides contribute to 10.3% of the additive mass. Therefore, the active ingredients are strongly diluted with SiO₂ or Al₂O₃, which hinders the transport of catalytic components to the boiler walls, finally resulting with the reduction of fuel combustion efficiency.
CN 1427068A discloses a coal combustion catalyst, which consists mainly of sodium chloride. The weight ratios of all the components of the disclosed combustion catalyst are: sodium chloride 90 - 95, potassium perchlorate 0.1 - 0.5, sodium chlorate 1 - 3, iron oxide black 1-2 and sodium percarbonate 1-5. The main catalyst component disclosed in CN 1427068A is sodium chloride and other chlorine compounds like chlorates and perchlorates.
It is commonly known that the presence of chlorine in the fuel additive negatively affects the environment. The use of chlorine compounds in the fuel additive composition as in D2 is inappropriate due to increased emission of chlorinated xenobiotics (polychlorinated dioxins and furans, i.e. PCDD and PCDF and polychlorinated biphenyls (PCB)). It is well known that with the increase of chlorine concentration in the fuel, the emission of dioxins into the environment increases.
Known fuel additives may be harmful to the environment (copper and chlorine compounds), cause excessive corrosion of boiler and flue pipes (chloride and sulphur compounds, fatty acid oxy-degradation products) and have pathogenic effect (cerium compounds).
Despite numerous research and attempts to solve the problem of ecological fuel combustion and soot formation, smog and damages to the environment, the quest for enhanced additive ensuring more effective and safer to the environment fuel consumption has been continued. The subject-matter of the invention is the ecological solid fuel additive, composed of triiron tetroxide and nitrates, containing 30-60% in weight of triiron tetroxide (Fe₃O₄), 10-30% in weight of nitrates selected from potassium nitrate (KNO₃), sodium nitrate (NaNO₃), ammonium nitrate (NH₄NO₃), or mixture of the abovementioned nitrates, preferably potassium nitrate, 5-30% in weight of sodium percarbonate (Na₂CO₃ - 1.5H₂O₂) and 10% in weight of anti-caking agent.
Advantageously, the anti-caking agent is powdered burnt clay.
Advantageously, Fe₃O₄ used for fuel additive production is free from FeSO₄. Advantageously, soot production and toxic compounds present in soot is limited.
Ecological solid fuel additive reducing soot production presented in the invention is a proposal for environment-friendly solid fuel combustion, preventing environmental contamination with soot accompanying pollutants such as: polyaromatic hydrocarbons (PAH), persistent organic radicals and heavy metals, whereas reduction of carbon black production prevents additionally the excessive fuel consumption (carbon black decreases the heating efficiency of a boiler) and increases combustion effectiveness.
Solid fuel additive according to the invention is characterized by that it contains 30-60% in weight of triiron tetroxide (Fe₃O₄), 10-30% in weight of potassium nitrate (KNO₃), sodium nitrate (NaNO₃), ammonium nitrate (NH₄NO₃), or mixture of the abovementioned nitrates, 5-30% in weight of sodium percarbonate (Na₂CO₃- 1.5H₂O₂) and 10% in weight of anti-caking agent e.g. powdered burnt clay.
It is important that Fe₃O₄ used for fuel additive production is free from FeSO₄ (FeSO₄ may act as the raw material for Fe₃O₄ production, which explains its presence). FeSO₄ presence in small quantities does not change the activity of fuel additive towards reducing the carbon black production, however carbon black obtained in presence of even small quantities of FeSO₄ is significantly less biodegradable (negative environmental impact).
The additive according to the invention, introduced to the combustion chamber with fuel or at the surface of the combusted fuel, is subject to partial thermal decomposition and releases the larg volume of gaseous products. Fuel additive components are activated in the temperature range of 80-650°C. Gaseous products of nitrates and sodium percarbonate decomposition reaction transport part of Fe₃O₄ quantity onto the carbonaceous deposite surface covering the heat exchanger. Fe₃O₄ particles in contact with heated fuel reach high temperature and then are transported on the carbonaceous deposite surface along with flue gas, where using its energy and catalytic oxidation properties catalyze the reaction of complete and total fuel combustion for hours.
Thermal decomposition of nitrates(V) is connected with production of atomic oxygen, which, at the moment of production (in statu nascendi) is highly reactive thanks to which it may easily oxidize the carbon black deposits covering the heat exchanger.
Decomposition of sodium percarbonate produces the peroxide and hydroxyl radicals, which, by means of chain reactions, are able to initiate the carbon black oxidation reaction. Advantageously, application of fuel additive results in significant lowering of carbon black oxidation temperature. When applying the said fuel additive, carbon black, thanks to lowering the energy of oxidation initiation in low-oxygen atmosphere, begins combustion in temperature of 300°C, whereas in the process without added fuel additives this temperature is >700°C.
Apart from decreasing the quantity of carbon black produced in the fuel combustion process, the chemical composition of the produced carbon black changes advantageously, in effect of which it contains less harmful substances. Modification of the composition in result of application of the ecological fuel additive facilitates biodegradation of substances contained in the carbon black, including cancerogenic polyaromatic hydrocarbons (PAH).

The additive according to the invention should be used in quantity of 0.5-2 kg per 1000 kg of fuel, advantageously 1.2 kg per 1000 kg of fuel in the case of application of additive in mixture with fuel. Chemical composition of the additive is decisive for its value, however its dose i.e. weight proportion of the additive to fuel unit (1000 kg) is almost of equal importance. During periodical application, the sufficient quantity is 50 g of additive in weekly intervals. In the cases of tendency of the heat exchanger to intensive covering with deposite resulting from quality of combusted fuel or the structure of heating installation, it is necessary to increase the fuel additive dose or its more frequent application.
Thanks to the fact that the ferrous compounds, in opposite to copper compounds, are not as toxic to the environment, the additive and produced carbon black is more environment-friendly. Combustion is more complete and produces less waste and smaller quantities of carbon black, which is additionally less toxic. There is also more energy produced. Solid fuel additive (coal, briquettes, etc.) according to the invention is a better ecological product than the additives in the composition, containing also: copper, chlorine, sulphur or fatty acids. The most significant pro-ecological effect of the fuel additive according to the invention is reduced carbon black production i.e. cancerogenic substance causing a greenhouse effect, carrier of polyaromatic hydrocarbons, stable organic radicals and heavy metals. Carbon black is also a pathogenic agent (circulatory and respiratory system diseases). Carbon black is a chemical and physical pollutant of air, water and soils, therefore its reduction constitutes a significant component of air protection programmes as well as the low emission reduction programmes (LERP). It is known that soot is a powerful absorbent of sunlight and contributes to climate warming and melting of glaciers covered with so called dry deposition (particulates) causing the greenhouse effect. Ecological effect of the additive according to the invention results also in lowering the combustion temperature and quantity of produced combustion gases, whereas the limited amount of produced soot is both less toxic and its components are biodegradable, and demonstrates the properties stimulating plant growth, including biomass increase.
To summarize, upon application of fuel additive according to the invention, less carbon black is produced, and the produced carbon black has different composition comparing to carbon black produced upon application of commercially available fuel additives or without their application, which makes it significantly less toxic i.e. more ecological.
To illustrate the solution according to the invention, a figure was enclosed, on which:

Figure 1 presents comparison of the content of the total of 4 components of soot sample determined using the HS-GC-MS method in the soot biodegradtion studies of two carbon black types;
Figure 2 presents the impact of carbon black (5% v/v) on the rate of occurrence of visible cotyledons of A. thaliana. NM carbon black - carbon black without fuel additive, B carbon black - carbon black with added commercially available additive containing significant quantities of NaCl and copper, A carbon black - carbon black with fuel additive according to the invention;
Figure 3 presents the impact of carbon black (5% v/v) on the rate of occurrence of the first leaf pair of A. thaliana. NM carbon black - carbon black without fuel additive, B carbon black - carbon black with added commercially available additive containing significant quantities of NaCl and copper, A carbon black - carbon black with fuel additive according to the invention;
Figure 4 presents the impact of the studied types of carbon black (5% v/v) on mass increase of A. thaliana upon 2 and 4 weeks of cultivation. NM carbon black - carbon black without fuel additive, B carbon black - carbon black with added commercially available additive containing significant quantities of NaCl and copper, A soot - carbon black with fuel additive according to the invention;
Figure 5 presents the impact of the tested soot types (5% v/v) on pigment content in A. thaliana upon 4 weeks of cultivation. NM carbon black - carbon black without fuel additive, B carbon black - carbon black with added commercially available additive containing significant quantities of NaCl and copper, A carbon black - carbon black with fuel additive according to the invention;
Figure 6 presents the graph of A. thaliana superoxide dismutases (SOD) activity upon native electrophoresis and histochemical staining of control plant homogenates (NM carbon black - carbon black without fuel additive, A carbon black -with newly-invented fuel additive, B carbon black - carbon black with added commercially available additive containing significant quantities of NaCl and Cu compounds);
Figure 7 presents the graph of fuel additive composition optimization - cubic model verification;
Figure 8 presents TGA and DSC thermograms of carbon black and carbon black with fuel additive samples;
Figure 9 presents the DP thermogram (red line - DSC, black line - TGA);
Figure 10 presents the thermovision image of Hercules auxiliary furnace (upon 8h from ignitron), whereas Figure 11 presents the thermovision image of SAS MI fine-coal auxiliary furnace (upon 10 hours from ignition).

The subject-matter of the invention is presented by the following examples of embodiment.

Example 1.

The additive containing the following was obtained:

triiron tetroxide 45 parts by weight

sodium percarbonate

30 parts by weight

potassium nitrate

15 parts by weight

powdered burnt clay 10 parts by weight

Upon mixing the components the fuel additive was obtained. The additive was introduced onto the surface of combusted fuel in coal boiler of 29 kW capacity. Quantity of carbon black covering the heat exchanger decreased 8 times, comparing to analogous combustion conditions without the additive. Thanks to this the chimney heat losses were reduced and fuel consumption was decreased. Soot deposited on the heat exchanger has lower carbon content and higher mineral component content (fly ash), comparing to carbon black produced during fuel consumption without the fuel additive. Application of fuel additive enables easier removal of deposits from heat exchanger. In addition it was observed that application of fuel additive reduces emission of nitrogen oxides in the flue gas.

Example 2.

Carbon black composition

Carbon black composition on the basis of elementary analysis was as follows:

Carbon black produced upon combustion of coal with no additives: 50.54% in weight of coal, 7.93% in weight of hydrogen and 4.65% in weight of nitrogen.
Carbon black upon application of fuel additive: coal 39.60% in weight, hydrogen 10.92% in weight, nitrogen 5.39% in weight.
Carbon black composition upon application of commercially available fuel additive based on CuSO₄ and NaCl: coal 44.66%, hydrogen 7.47%, nitrogen 5.01% (in weight).

Example 3.

The additive containing the following was obtained:

triiron tetroxide 45 parts by weight

sodium percarbonate

30 parts by weight

potassium nitrate

15 parts by weight

powdered burnt clay 10 parts by weight

Upon mixing the components the fuel additive was obtained. The additive was introduced onto the surface of combusted fuel in coal boiler of 29 kW capacity. Quantity of carbon black covering the heat exchanger decreased 8 times, thanks to which the chimney heat losses were reduced and fuel consumption was decreased. Soot deposited on the heat exchanger has lower carbon content and higher mineral component content (fly ash), comparing to carbon black produced during fuel consumption without the fuel additive, which enabled easier removal of deposits from heat exchanger. In addition it was observed that application of fuel additive reduces emission of nitrogen oxides in the fumes.

Example 4.

The additive containing the following was obtained:

triiron tetroxide 30 parts by weight

sodium percarbonate

20 parts by weight

potassium nitrate

40 parts by weight

powdered burnt clay 10 parts by weight

Upon mixing the components the fuel additive was obtained. The additive was introduced onto the surface of combusted fuel in coal boiler of 29 kW capacity. Quantity of carbon black covering the heat exchanger decreased 5 times.

Example 5.

The additive containing the following was obtained:

triiron tetroxide 30 parts by weight

sodium percarbonate

30 parts by weight

potassium nitrate

30 parts by weight

powdered burnt clay 10 parts by weight

Upon mixing the components the fuel additive was obtained. The additive was introduced onto the surface of combusted fuel in coal boiler of 29 kW capacity. Quantity of carbon black covering the heat exchanger decreased 5 times.
In the description of the biological tests the following expression was used: 'carbon black produced in result of combustion with fuel additive according to the invention', which means carbon black produced with the additive being the subject-matter of the invention.
The other types of carbon black used in the description include:

1. non-modified carbon black i.e. produced with no additive (catalyst);
2. carbon black with fuel additive available on the market, however based on NaCl and copper (name not provided on purpose). The additive according to the invention, in contrary to the other additives available on the market, is based on iron compounds, more environmental friendly comparing to copper compounds demonstrating specific toxicity to environmental microflora.

Biological interactions of carbon black produced in result of combustion with fuel additive according to the invention in solid-fuel burning boilers.

Example 6.

Studying the impact of carbon black produced in result of combustion with the invented fuel additive on soil bacteria

In conical flasks (labelled A and B) of 100 ml volume containing 50 ml sterile liquid nutrient medium LB MIX (Table 1) each, the culture of two common soil bacteria: Pseudomonas aeruginosa - flask A and Bacillus subtilis - flask B was established. Table 1. Composition of liquid nutrient medium LB MIX used for bacteria culture (pH - 7.00)

Composition Mass [g/l]

Casein peptone 10.00

Yeast extract 5.00

Sodium chloride 10.00
The study on the impact of carbon black produced with the invented fuel additive and carbon black produced in result of combustion with no additive on common soil microorganisms - Pseudomonas aeruginosa and Bacillus subtilis. The study was performed for two concentrations (w/v) of carbon black in the nutrient medium i.e. 0.30% and 6.00%. All tests were repeated 10 times. In the case of both bacterial strains, regardless of type and concentration of carbon black, bacteria growth was observed. Thanks to the applied dilutions, carrying-out of the quantitative tests was possible. Average number of grown bacterial cultures in each analyzed case at the highest dilution of the culture suspension was 9 ± 4.
With regard to the above, application of fuel additive according to the invention is advantageous, since despite higher efficiency of solid fuel combustion, including decreased carbon black quantity, toxicity of this carbon black to the tested soil microorganisms does not increase.

Example 7.

Testing the soil bacterial capacity for biodegradation of the selected toxic components of carbon black with the invented fuel additive.
The tests were carried out with the use of two types of carbon black (carbon black produced in result of combustion with the invented fuel additive and non-modified carbon black (NM carbon black)) as well as Pseudomonas aeruginosa (A) and Bacillus subtilis (B) bacteria. Samples of each type of carbon black were grinded carefully in the mortar and 0.20 g to each conical flask of 100 ml volume was weighted out. Then each flask was filled with 50 ml of BSM mineral nutrient medium containing no carbon source (Table 2).

Table 2. Composition of BSM mineral nutrient medium containing no carbon source (pH 7.00)

*Composition*	Mass [g/l]
Potassium dihydrogen phosphate	0.38
Dipotassium phosphate	0.60
Magnesium sulfate heptahydrate	0.20
Ammonium chloride	1.00
Iron (III) chloride hexahydrate	0.08

The flasks with BSM nutrient medium and relevant type of carbon black were placed in the batch retort. After sterilization one of each type of the flasks with relevant type of carbon were left as control sample (no bacteria), whereas the remaining two containing the same type of carbon black were filled with the same amount of cells of one of two bacterial strains (A or B, the principle of standardization of the number of cells in inoculum was described in Example 6). The cultures were kept in darkness to prevent possible photolysis of sample components and incubated for 4 weeks (30°C, RPM 150). The test was repeated 10 times.
Upon completion of cultivations, 15 µl was sampled from each solution and streaked on LB MIX agar medium to verify, whether the inoculated organisms survived the incubation period. The remaining part of the solutions were filtered using the Buchner funnel under decreased pressure via hard filters (degree: 390, weight: 84 g/sq m), selected with regard to the most effective recovery of carbon black from the solutions and the materials, from which these were produced (possibly resistant to high temperature e.g. 150ºC used in headspace (HS) technique, consisting in analysis of gas phase above the solid or liqid sample). The filters were placed in glass vials and left for drying in ambient temperature for 5 days and then closed tightly.
Analogously, the control samples i.e. containing the relevant type of carbon black however with no bacteria added, were filtered. All residues on the filters and weighted portions of carbon black were analyzed using the Headspace Gas Chromatography/Mass Spectrometry (HS-GC-MS) after app. 15 minutes of vials thermostating in temperature 150ºC directly before inoculation (50 µl). The dispenser temperature was set to 250ºC, carrier gas stream proportion (helium) was 10:1, column flow was 1 ml/min, whereas linear speed amounted to 36 cm/sec. The analysis used the programmable temperature change method: 60ºC for 1 minute, temperature increase by 10ºC/minute until the maximum temperature of 250ºC (maintained for 1 minute) was reached. The analyses were carried out with the use of capillary column HP-1 MS (Agilent Technologies) of 30 m length, 0.25 mm diameter and 1µm film thickness. The transfer line was maintained in temperature of 250ºC, MS source temperature was 230ºC, whereas quadrupole temperature was 150ºC and dwell time - 100 ms.
Cumulative content of phenol (m/z = 94, RT = app. 7.78 min.), naphtalene (m/z = 128; RT = app. 10.04 min.), phenanthrene (m/z = 178; RT = app. 17.67 min.) and anthracene (m/z = 178; RT = app. 17.79 min.) was determined in the samples. The results of determination of the total of 4 selected polyaromatic hydrocarbons demonstrate the changes in the carbon black structure (Fig. 1).

The phenol, naphthalene, phenanthrene and anthracene biodegradation rate without the fuel additives and with the ecological fuel additive was researched. The highest biodegradation rate of the determined pollutants was observed for the samples of carbon black produced with the use of additive according to the invention, with added P. aeruginosa (A) (77.9 ± 3.2%), followed by B. subtilis (B) (40,2 ± 2,8%). In the case of non-modified carbon black, this rate amounted to 59.7 ± 2.7% for the culture with P. aeruginosa bacteria and 29.2 ± 1.6% for B. subtilis, respectively. In addition, it was observed that the primary samples of carbon black produced with fuel additive according to the invention contained significantly lower quantity of determined compounds comparing to non-modified carbon black.
Application of fuel additive according to the invention is thus advantageous, since higher efficiency of solid fuel combustion, including decreased carbon black quantity, is accompanied by lower amount of toxic compounds in the produced carbon black comparing to the carbon black produced with no additive, and these compounds are easier biodegradable by common soil bacteria and do not increase mortality of these bacteria.

Example 8.

Studying the impact on carbon black produced in result of combustion with the invented on the selected physiological - biochemical parameters of plants

The impact of carbon black produced with the invented fuel additive on such physiological - biochemical parameters of plants as:

a) seed germination;
b) plant growth,
c) biomass production,
d) photosynthetic pigment concentration;
e) anti-oxidative enzyme activity

The tested plant was thale cress (Arabidopsis thaliana). Arabidopsis thaliana is a model plant commonly used in genetic tests (known genome) as well as biochemical, physiological and toxicological tests (certain standards in the area of assessment of different pollutants' phytotoxicity, including PAH recommend this species). Recently, the new methods of the use of this plant in the initial drug testing have been developed - to reduce the number of animal testing.
The plant was subject to the activity of three types of carbon black:

carbon black produced with the invented additive (A carbon black);
carbon black with the additive available on the market, produced with the use of sodium chloride and significant quantities of copper salt (B carbon black) (components present in vast majority of fuel additives available on the market);
carbon black produced with no additive (NM carbon black).

in vitro,

Table 3. Composition of Gamborg B5 nutrient medium

*Composition*	*Concentration [µM]*	Concentration [mg/l]
Vitamins
mio-inositol	555.1	100.0
thiamine-HCl	29.6	10.0
nicotinic acid	8.1	1.0
piridoxine-HCl	4.9	1.0

Mineral soils
NaH₂PO₄ · H₂O	1100.0	150.0
CaCl₂ · 2H₂O	1000.0	150.0
MgSO₄ · 7H₂O	1000.0	250.0
(NH₄)₂SO₄	1000.0	134.0
FeSO₄ · 7H₂O	100.0	27.8
Na₂EDTA · 2H₂O	100.0	37.3
MnSO₄ · H₂O	60.0	10.0
H₃BO₃	50.0	3.0
ZnSO₄ · 7H₂O	7.0	2.0
KI	4.5	0.75
Na₂MoO₄ · 2H₂O	1.0	0.25
CuSO₄ · 5H₂O	0.1	0.025
CoSO₄ · 6H₂O	0.1	0.025

Apart from control plants (not treated with carbon black), the plants were subject to the following concentrations of each of the tested carbon blacks: 1.25; 2.5; 5% (v/v) or only the highest of them.
Arabidopsis thaliana seeds were sterilized as follows in the eppendorf test-tube:

seeds shaken for 1 minute in 70% ethanol solution;
ethanol was eliminated and the seeds were treated in 10% ACE solution for 7 minutes with continuous mixing;
upon elimination of ACE solution, the seeds were washed four times with sterile deionized water in the following sequence: 1x1minute + 3x5 minutes.

^-2

^{- 1}

a) carbon black impact on seed germination

In the first days of culture, seed germination rate and growth rate of control plant seedlings has not deviated significantly from the germination rate on the nutrient media containing carbon black, regardless of the type of applied carbon black (Fig. 2). One should emphasize that in the case of carbon black with the invented fuel additive, starting from the third day of the experiment, the percentage rate of the best-grown seedlings was the highest both among the tested carbon blacks and slightly exceeded the control cultures.
The similar results were obtained when analyzing further growth of seedlings. However the percentage rate of the plants treated with A and B carbon black was the lowest in the first day of occurrence of the first leaf pair among all analyzed samples, upon two days the percentage rate of plants with the formed first leaf pair among the plants treated with carbon black was the highest in the case of A carbon black (with additive according to the invention), and upon the next two days, the average experimental value did not differ from the value recorded for control, however the plants treated with A carbon black featured more repeatable values (their distribution was significantly narrower comparing to all tested samples, including the control sample) (Fig. 3).
Application of the additive according to the invention is advantageous, since the carbon black produced in the presence thereof both has no inhibiting effect on the number of germinated seeds and features properties stimulating growth of the young seedlings.

b) impact of carbon black on growth of overground parts of the plants

Growth of overground part of the plant was measured in 7th and 14th day of culture. The measurement was performed along the plant from the highest point of cotyledon or plant leaves, to the part of stem bordering the nutrient medium.
The results of the experiment demonstrating that the plants cultivated on the nutrient media containing A carbon black (with fuel additive according to the invention) reached the greatest height. This was also the only carbon black, increase of content of which in the nutrient medium resulted in the intensified growth of the plant. Upon 7 days of culture, average height of plants treated with carbon black produced in result of application of the fuel additive according to the invention, exceeded the control plants by, respectively:

17% at 1.25% (v/v) content of carbon black in the nutrient medium),
37% (at 2.5% (v/v) content of carbon black in the nutrient medium)
60% (at 5% (v/v) content of carbon black in the nutrient medium).

A

thaliana

c) impact of carbon black on biomass production

The results of the experiment demonstrated that both upon two and four weeks of observation among the plants treated with carbon black, the highest average mass (converted into single plant) was recorded in plants growing in presence of carbon black A (with the additive according to the invention). Average mass of these plants at lower concentrations of carbon black A (1.25% and 2.5%) was in all tested types of carbon black the most approximated to mass of control plants, however, as in the case of each type of carbon black, lower than the control value. For the highest concentration of carbon black A (5% v/v), mass of tested plants upon 4 weeks of the experiment exceeded the mass of control plants by more than 30% (Fig. 4).
It is advantageous to use the additive according to the invention, since the carbon black produced in the presence thereof demonstrates visible fertilizing properties in plant biomass production.

d) impact of carbon black on photosynthetic pigments content

Composition of the most important group of photosynthetic pigments, i.e. chlorophyll a, b and carotenoids, was analyzed. These pigments are necessary for proper course of photosynthesis and condition the effective conversion of luminous energy into hydrocarbons. Pigments deficiencies or irregularities in their proportion decrease the photosynthetic efficiency and therefore widely-understood plant production.
Pigment content was measured in four-week leaves of A. thaliana by sampling 4 leaves from each plant, homogenization and extraction of pigments with 80% (v/v) acetone solution.
To calculate the pigment content, absorbance of the obtained extract was measured using the Jasco V-650 spectrophotometer at the following wavelengths: 662nm, 645nm and 470nm (Lichtenthaler method, 1987): $c_{chlA} = 11.75 A_{662} - 2.35 A_{645} [μ g / 1 ml of extract]$
$c_{chlB} = 18.61 A_{645} - 3.96 A_{662} [μ g / 1 ml of extract]$
$c_{kar} = (1000 A_{470} - 2.27 c_{chlA} - 81.4 c_{chlb}) : 227 [μ g / 1 ml of extract]$
The obtained results were converted into pigment content in 1g of fresh leaf mass (Fig. 5)
Excluding the plants growing in presence of carbon black with commercially available fuel additive (B carbon black), the proportions of individual pigments were correct. The plants growing in presence of B carbon black featured definitely deficient chlorophyll and carotenoids content, which may be decisive for their low productivity (low growth and biomass). The highest pigment content was observed in plants growing on the nutrient medium with carbon black with additive according to the invention (carbon black A).
The additive according to the invention stimulates plant photosynthetic pigment production, including valuable for health carotenoids, which is advantageous in context of plant growth, productivity and nutritive values.

e) impact of carbon black on anti-oxidative enzymes activity

Impact of A, B and NM carbon blacks on the activity of anti-oxidative enzymes was studied on 8-week plants. The tested enzymes were superoxide dismutases (SOD), being the metalloproteins protecting the cellular structures against oxidative stress. Depending on the bonded co-factor, they may have the form of copper/zinc, iron or manganese dismutases. A. thaliana contains the genes of all the above-mentioned forms. Copper/zinc dismutases CuZnSOD) are localized primarily in the chloroplasts, peroxisomes and cytosol, whereas Iron dismutases (FeSOD) are present in chloroplasts and manganese dismutases (MnSOD) in mitochondria and peroxisomes (Kliebenstein et al. 1998, Malecka & Tomaszewska 2005).
Enzyme activity was tested using the native electrophoresis with histochemical staining method. Electrophoresis was carried out on polyacrylamide gels (11.6% (bottom) and 0.8% (upper)) at 180V in 4°C. Upon electrophoresis, the gels were subject to 30-minute staining to detect SOD activity (Miszalski et al. 1998).
It was demonstrated that the plants treated with A carbon black presented no differences in context of isoform activity comparing to control plants and plants subject to NM carbon black. In all these plants, a dominating SOD isoform was iron dismutase (FeSOD). It was stated that in the plants treated with carbon black with additive according to the invention, as well as in plants treated with NM carbon black, activity of FeSOD isoform does not depend on carbon black concentration. Activity of the remaining isoforms i.e. MnSOD or CuZnSOD in plants treated with A carbon black, NM carbon black and control plants remains at similar and very low level, which makes the enzymatic profile of plants treated with A, NM carbon black and control plants in context of SOD activity identical (Fig. 6).
In the case of plants treated with B carbon black, a rapid increase in activity of copper/zinc forms was observed comparing to the control samples and plants cultivated with the two remaining types of carbon black (NM and A). CuZnSOD isoforms featured the highest activity, which increased along with increase of carbon black concentration in the nutrient medium. In plants treated with B carbon black a minor increase of MnSOD isoform activity was observed, whereas the activity of FeSOD isoform was comparable with activity in control extracts and plants subject to the remaining types of carbon black (NM and A) (Fig. 6).
The additive according to the invention applied in the production of carbon black A does not increase the oxidative stress in plant cells, both in plants not treated with carbon black (control) and growing in presence of carbon black produced with no additive.
The commonly applied and available on the market additive contributes to production of carbon black causing a harmful oxidative stress in plant cells reflecting in rapid increase of activity of additional SOD isoforms, activity of which in the control plants and plants treated with NM and A carbon blacks was insignificant.
Application of ecological additive according to the invention is therefore advantageous, since in the presence thereof carbon black does not contribute to generation of oxidative stress in plant cells.

Description of the effects of fuel additive according to the invention in the research on low efficiency boiler

Impact of fuel additive depending on share of active substances on coverage with carbon black of the heat exchanger of coal-burning boiler of 29 kW capacity was researched. The research results are presented in Table 4.

A mathematical model describing coverage of heat exchanger with soot in function of fuel additive composition was developed (Fig. 7, formula 1). Temperature range, in which the fuel additive is active for carbon black oxidation was specified (Fig. 8) followed by temperature range, in which the fuel additive is subject to thermal reactions (Fig. 9). Measurements of temperature distribution in furnace of central heating boiler were performed, according to which the furnace temperature is sufficient to activate the fuel additive (Fig. 10).

Table 4. Optimization plan for the fuel additive composition (FA)

	Fe₃O₄ mass [g]	Percarbonate mass [g]	Nitrate mass [g]	Carbon black mass [g]	Coverage of heat exchanger with soot [g/m²]
#1	45	0	0	2.46	48.81
#2	0	45	0	1.91	37.90
#3	0	0	45	1.82	36.11
#4	30	15	0	1.07	21.23
#5	30	0	15	0.94	18.65
#6	15	30	0	1.45	28.77
#7	15	0	30	1.39	27.58
#8	0	15	30	1.04	20.63
#9	0	30	15	1.72	34.13
#10	15	15	15	1.01	20.04
#11	15	10	20	0.76	15.08
#12	25	7	13	0.65	12.89

Impact of fuel additive composition on coverage of heat exchanger with carbon black was researched. Experiments #1-10 result from the experiment plan (simplex plan, grade 3 {3;3}). Experiments # 11 and 12 were used to develop a mathematical model and optimize the experiment towards the extreme (minimum) of the objective function, physical sense of which corresponds to the lowest coverage of heat exchanger with deposited soot.
Fig. 7 presents the graph illustrating that the lowest coverage of heat exchanger is obtained when the chemical composition of the additive ranges between points # 4, 5, 10 and 11. $f (π) = 48.90 x + 37.76 y + 36.13 z - 82.40 xy - 89.06 xz - 42.61 yz + 27.38 xyz - 81.30 xy (x - y) - 93.15 xz (x - z) + 90.22 yz (y - z)$
where:

x -Fe₃O₄ mass,
y - sodium percarbonate mass,
z- nitrate mass, $x + y + z = 15 g$

Coverage of coal-burning boiler heat exchanger with carbon black with no added fuel additive was, in average, 76.8 ± 8.4 g/m² (n=5).
The new fuel additive reduces significantly the temperature of carbon black oxidation, which was presented on Fig. 8. Fig. 8 features the thermogravimetric analysis curves and differential scanning calorimetry (DSC) analysis curves, performed for the carbon black samples (black line) and carbon black with fuel additive (red line). In the case of carbon black sample, the temperature increase is accompanied with slow decrease in mass caused by organic compounds desorption. This process is of endothermic nature. In the case of carbon black with fuel additive, a clear exothermic effect is observed, which is proved by maximum on the DSC curve.
The thermal effect corresponding to carbon black oxidation in the sample containing the fuel additive is accompanied by significant mass reduction, proving the catalytic activity of fuel additive.
According to Fig. 9, complete activation of the new fuel additive takes place in temperature up to 650°C, therefore introduction of fuel additive when the boiler is well heated is advantageous. Inflow of adequate air quantity to the combustion chamber ensures relevant combustion temperature, which in low efficiency boilers may exceed even 1000°C (Fig. 10). In fine coal boiler, combustion temperature is slightly lower, however sufficient for thermal decomposition of the fuel additive (Fig. 11).
Intensive airflow via the combusted fuel results in blowing of heated catalyst particles away. Fe₃O₄ particles are transported along with fumes and transmitted at the surface of the heat exchanger, where the carbon black oxidation process takes place. Determinations of iron content in carbon black produced from fuel combustion and combustion of fuel with fuel additive demonstrate that carbon black produced in chemically - supported process has higher iron content.

Literature:

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Claims

Ecological solid fuel additive composed of triiron tetroxide and nitrates,
characterized in that it contains 30-60% in weight of triiron tetroxide (Fe₃O₄), 10-30% in weight of nitrates selected from potassium nitrate (KNO₃), sodium nitrate (NaNO₃), ammonium nitrate (NH₄NO₃), or mixture of the abovementioned nitrates, preferably potassium nitrate, 5-30% in weight of sodium percarbonate (Na₂CO₃ · 1.5H₂O₂) and 10% in weight of anti-caking agent.
Solid fuel additive according to claim 1, characterized in that the anti-caking agent is the powdered burnt clay.
Solid fuel additive according to claim 1, characterized in that Fe₃O₄ used for production of the fuel additive is free from FeSO₄.