Field of Invention:
The present invention relates to a fuel additive composition to enhance thermal output, reduce NOX emission and decreasing concentration of hazardous trace metal in fly ash during coal combustion.
Background Of invention:
Most of our energy demand is met by the thermal power plants, which use coal for their operation. Coal has become an important source of energy in this century and it will continue to be prime source for the coming hundred years though its depletion is imminent. The growing energy demand for a rapidly developing country like India, it has become imperative to look at other prospects of energy production and saving. In India, the demand for production and consumption of coal are very huge. Most of the raw coals mined every year are directly used as fuels. Hence, it is very important and necessary to improve the burning of coal so as to save energy and minimize environmental pollution. Generally, high efficiency and less pollutant generation the mark of a quality coal burning.
In addition, the utilization of low-rank coals, which occupy many lands and pollute environment, is a problem that has to be solved. Among all kinds of methods of achieving the above purposes, the use of additives in the process of coal burning is an effectual one. In recent years, the application of combustion additives is picking up quickly; coal mixed with the additives are being used as fuels in electricity generation, cement industry and civil utilization in many developed countries like China, USA etc.
The major portion of power generation in India is also being done using coal. However, high ash content in Indian coal and inefficient combustion technologies contribute to India's emission of air particulates and other trace gases like high levels of NOX, huge quantities of fly ash which become a problem for disposal etc. that are responsible for the greenhouse effect, polluting the local as well as global environment.
Presently, increasing coal use or blending Indian coal with imported coal of higher calorific value (for increasing electricity production) needs to be carefully addressed through viable technological options. Oxidation of nitric oxide (NO) discharged in combustion products forms nitrogen dioxide (N02) in the atmosphere is another problem. These oxides of nitrogen are responsible for the formation of photochemical smog.
As a consequence of the increased emphasis on the environmental impacts of energy production world wide, there is now search for the improved technologies for combustion and design parameters. In order to reduce these hazardous emissions with increased the thermal efficiency of the combustion system is one of the ways out of this precarious situation. The use of additives is one such way of improving the combustion characteristics of a process. But fundamental research works on the burning characteristics of coals doped with

the coal-burning additives should be carried out in order to give scientific basis to the application of the coal-burning additives.
W006088462A1 discloses a mixed alcohol formulas used as a fuel additive in gasoline, diesel, jet fuel, aviation gasoline, heating oil, bunker oil, coal, petroleum coke or as a neat fuel in and of itself. The mixed alcohols formulations comprises of CrCs alcohols, or in the alternative, CrCs alcohols or higher Crdo alcohols in order to boost energy content. The CrC5 mixed alcohols contain more ethanol than methanol with declining amounts of propanol, butanol and pentanol. CrC8 mixed alcohols contains the same, with declining amounts of hexanol, heptanol and octanol. CrCio mixed alcohols contains the same, with declining amounts of nananol and decanol. Synthetically produced mixed alcohol formulas feature higher octane and energy densities than either MTBE or fermented grain ethanol; more stable Reid Vapor Pressure blending characteristics; and increased solubility effects on condensate water. The primary benefits of mixed alcohols are increased combustion efficiencies, reduced emissions profiles and low production costs.
W004104141A2 a US20060218853A1 teaches a fuel additive composition for preventing scaling, excluding of soot, clinker and sludge, and controlling flame in combustion apparatus. Said composition comprising hydrogen peroxide, an amine-based stabilizer, borax, and sodium hydroxide. The composition is added to such fuel as coal, oil, and gas to facilitate combustion and remove impurities in a combustion apparatus, thereby improving thermal efficiency, and it reduces discharge of noxious gases such as SOX, NOX, and CO.
US7101493 discloses a composition for suppressing coal dust includes a metal-containing compound, such as an organo-manganese, that provides the additional benefit of being a combustion improver. The organometallic compound is mixed with any appropriate dust suppressant liquid. The organometallic compound may include methylcyclopentadienyl manganese tricarbonyl.
W002077132A1, EP1375631A4 and US20040079925A1 teaches a fuel additive is directed to preventing slagging, a phenomenon caused by the ash in a fuel particularly during the combustion of a fuel having such a large ash content as is typically found in coal or oil coke, for example. It is formed of a composition having one or more compounds selected from among aluminum compounds, silica compounds, titanium compounds and zirconium compounds invariably of the form of ultrafine particles having a particle diameter in the range of 3 to 200 nm and no less than 2 wt. % of an alkali metal (R = Na or K) compound as reduced to the R20 concentration dispersed in a stable state in water and/or oil. When a liquid fuel oil and/or a solid fuel is made to incorporate the fuel additive therein and then subjected to combustion, the deposited ash can be easily peeled and shed from the surface of the furnace wall or the water pipes.

CN1724621A discloses a fuel coal additive. The main feature is that mixes the salt combustion adjuvant and calcium oxide absorbent as the ratio of 4-10%:96-90%. The invention uses the combustion supporting and catalysis of Na and Cl that could be decomposed from melt salt. The C02 from burning calcium oxide could absorb the S02 from burning coal and finally form CaCO.-). Thus, the aim of benefit for the environment would be achieved.
CN1710036A teaches a fuel combustion-reinforcing agent. Said invention involves a fuel additive, especially a kind of high-efficient fuel burning-assistant to solve the defect of present fuel additive with unsatisfactory result and low energy-conserving efficiency. A high-efficient fuel fire assistant, it in weight to proportion is: oxalate 40-50%, 2-ethylhexanol 25-35%, dimethylether 1-5%, tert-butylmethylether 2-10 ether, three contract triethylamine 2-8%, triethylamine 2-10%, and amylnitrate 0-5%, C10H10Fe 2-8%, Ci2.16H25.33S03Na 1-5%, special oxygen 0.2-1%. At first, fetch the material according to matching, then mix disposing according to the order of matching, join a kind of raw materials each time, need mixing for 3-6 minutes fast.
JP2004083796A2 discloses a fuel additive composed of a composition produced from ultrafine silica sol particles having a particle diameter of 3-200 nm and ultrafine Al(OH)3 particles and/or ultrafine Zr compound particles surface-modified with a surfactant and having a particle diameter of 2-100 nm by dispersing the Al(OH)3 particles and the Zr compound particles in water. The fuel additive is added to a liquid fuel oil or a solid fuel and the fuel is burned.
JP2004018704A2 discloses a fuel additive comprises a composition having one or more of an Al compound, an Si compound, a Ti compound, and a Zr compound, each in a super-fine particulate having a particulate size of 3-200 nm, and a water-soluble explosive compound dissolved or dispersed in water.
CN1090316A teaches an effective energy-saving oil fuel additive. An efficient energy-saving additive for fuel oil features its 32 components such as coal tar, alcohol, acetone, benzene, rape oil, glycerin, MoS2, graphite, Teflon etc. Its advantages include combustion assistance, resisting detonation, friction reduction and less carbon collection. Fuel saving rate is up to 10-30%.
JP62265391A2 teaches a fuel additive comprising a finely divided iron oxide which is laminar or annular i.e., consisting of laminate having a through hole in the center thereof, is mixed either with a machine oil, a dispersing agent, a stabilizing agent (e.g., sorbitan mono-oleate), etc., to give an oil-slurry fuel additive or with water, ethylene glycol, a stabilizing agent, etc. to give a water- slurry fuel additive. This oil-slurry or water-slurry fuel additive contains iron oxide particles having a laminar form free of sharp edges; therefore, the incorporation of this additive into a fuel even in a large amount will neither cause a pump, a burner tip, etc., to wear out nor cause settling of the additive.

Most of the compositions of prior art use hazardous transitional metal elements, which are emitted as by product during the combustion and increase the concentration of hazardous trace metal in fly ash. Secondly the compounds used in the additives are quite expensive.
Most of the prior art compositions have two components out of which one is adjuvant. Basically single component catalyst. Further, the adsorbent which is probably the CaCOS produces C02 and that somehow manages to consume in the due course. It has no effect on temperature enhancement or on trace metal concentration.
Present invention provides a fuel additive composition, which obviates the drawbacks of the prior art and has increased combustion efficiencies, reduced emissions profiles and low production costs. It also has notable economical benefit and social benefit.
Summary of the Invention:
Present invention relates to a fuel additive composition to enhance thermal output, reduce NOX emission and decreasing concentration of hazardous trace metal in fly ash during coal combustion comprising:
85 to 95 % of a non-metallic salt selected from the elements of group VA to VIIA,
2 to 10% of metallic salt selected from the group of elements from IA to
IMA,
3 to 5 % of an organic support selected from the group of amines.
The non-metallic salts are selected from ammonium salts.
The additive composition of the present invention comprises one or more metal salts. The cationic part of metallic salt is selected from sodium, potassium, beryllium, magnesium and aluminum preferably sodium. The anionic part of the metal salt is selected from nitrate, chloride, bromide, iodide and sulphate.
The organic support is an aliphatic amine preferably hexamine.
The present invention further provides a coal composition obtained by spraying 1% aqueous solution of fuel additive to enhance thermal output, reduce NOX emission and decreasing concentration of hazardous trace metal in fly ash during coal combustion.
Description of the drawings:
Fig. 1: Schematic of the Experimental Set up
Fig. 2: Detailed outline of the Test Coal Combustor
Fig. 3: Flue Gas Temperature Variation with Coal Feed Rate

Fig. 4: Variation of NO Emission level with Coal Feed Rate Detailed description of the Invention:
The objective of the instant invention is to increase combustion efficiencies, reduced emissions profiles and low production costs. To achieve the said objective the invention provides a fuel additive composition to enhance thermal output, reduce NOX emission and decreasing concentration of hazardous trace metal in fly ash during coal combustion comprising:
85 to 95 % of a non-metallic salt selected from the elements of group VA to V1IA,
2 to 10% of metallic salt selected from the group of elements from IA to
MIA,
3 to 5 % of an organic support selected from the group of amines.
The instant invention has three components and all three are necessary for an efficient combustion. Further, it does not contain any CaC03 proportion therefore, leads to lesser emission of C02 and NOx. Also the instant invention has substantial effect on trace metal as well as on thermal output of the combustion system.
The studies were carried to find out the effect of the combustion additive Supertherm K2R on the pulverized coal combustion. The following conclusions can be drawn from the above study.
1. The additive has substantial role in enhancing the thermal out put of the
combustion system in test conditions.
2. There is a temperature increase in the range of 12-15% when the
combustor is operated in the low feed conditions, which further widens
as the feed rate increases.
3. There is a definite role in the heat generation during a combustion
process for pulverized coal combustion.
4. It also marginally reduces emission of highly polluting gases like Nitric
Oxide (NO).
5. It has a profound effect in reducing the trace metal quantities in the fly
ash generated from the coal mixed with this additive.
Figure 1 shows the schematic diagram of the experimental set up used for the study. The combustor was an insulated cylindrical tube of diameter 72 mm and of length 1.2 meter placed horizontally. A thickness of 50-70 mm of insulating material was placed outside the combustor to check the radiative heat loss to the surrounding. Dry air was supplied to the combustor in two stages from the compressor. The primary air was supplied through the coal container which carried weighed amount of pulverized coal. Secondary tangential air along with LPG fuel was used for initial heating of the combustor. The temperature

measuring system was fitted to the burner exit to measure the flue gas temperature. The emission was measured using gas analyzer connected to the water-cooled sampling probe. The burnt ash was tested for trace metal concentrations using the Atomic Absorption Spectroscopy (AAS). The detail description of the test procedure has been given later in the experimental procedure section.
TEST BURNER:
The structure of the pulverized burner indigenously developed to suit the test conditions of the furnace was developed in our laboratory. The burner is designed to have a coal combustion capacity of about 5kg per hour. The shape of the pulverized coal combustor is cylindrical SS tube placed horizontally during combustion. Figure 2 shows the enlarged diagram of the combustor, which is of 72 mm diameter and 1.2 meter long. There are two air supply ports in the burner namely Primary air, which comes along with coal to the burner. The secondary port for air is a tangential one, which helps in the better mixing of coal with air and helps to increase the residence time to insure better combustion.
EXPERIMENTAL METHOD AND MEASUREMENT:
In the initial stages of the experiment, LPG was supplied along with tangential air to warm the combustor, which will help the initiation of coal burning. The LPG supply was stopped after the combustor reached sufficiently high temperature. Then coal was supplied through primary air supply port by discontinuing the LPG supply and tangential air supply was reduced. Flue gas temperature measurement was taken after the temperature raised to a maximum and less fluctuation was observed through the temperature scanner connected to two K type thermocouples attached to the burner exit. Then the measurement for emission was done through a water-cooled sample handling system which supplied cooled flue gas to the NOX analyzer based on Chemiluminescence based principle. During the process the ratio of primary to secondary air was kept at 100-40 liter/min. Then the time for entire process was measured and the coal left in the container was measured. The quantity of ash left in the combustor was also measured. Few grams of this ash were subjected to acid digestion and the trace metal content was measured using the standard procedure with the help of Atomic Absorption Spectroscopy (AAS). Two separate experiments were conducted one with pure coal and other with the additive to study the effect of the additive, Supertherm K2R on trace metal contents. The detailed discussions of the results are as follows.
EXPERIMENTAL RESULTS:
The findings of the study have been characterized in terms of flue gas temperature, emission from the coal combustion and trace metal concentration

in ash generated during the combustion. The detailed description has been laid out in the subsequent section of the report.
FLUE GAS TEMPERATURE:
The measured flue gas temperature is plotted by taking into consideration of the coal feed rate to the combustor in Fig. 3. It can be seen from the plot that the temperature of the flue gas increases as the coal feed rate is increased. It happens to the pure coal as well as coal mixed with the additive. It can also be seen that, there is a substantial increase in the flue gas temperature when the coal is mixed with the catalyst. The catalytic and accelerating effects of Supertherm K2R on the burning coals increased the temperature of the system in range of 12-15% under test conditions, which may be due the better oxidation of the fuel. This indicates that there is remarkable enhancement in heat generation capacity of the fuel is due to the additive.
POLLUTANT EMISSION FROM THE COMBUSTION:
Due to the stringent emission norms coming up time to time, we thought of seeing the effect of the Supertherm K2R on emission during the combustion. The emission for one of the important pollutants like NO was done by gas analyzer and the data has been plotted out in Fig 4. The variation for NO emission level is plotted against the coal feed rate in Fig. 4. It is observed that the NO emission level increased with the increase in the coal feed rate for both the cases. However, a decrease in NO emission level was observed when additive was mixed with the coal. A variation in reduction ranging from 5% to 9% was observed when the feed rate was doubled from 15 g/min to 30 g/min.
CONCENTRATION OF TRACE METALS IN THE FLY ASH:
The trace metal content for seven metals were measured from both the fly ash generated by the combustion of simple coal as well as the Supertherm added coal. The ash samples were acid digested and subjected to the analysis as per the standard methods with the help of Atomic Absorption Spectroscopy (AAS). The data has been provided in Table-1. It can be seen that in case of five metals there was sufficient degradation in the metal concentration. In case of the other two metals there was a negligible increase in the percentage of metal, which can be attributed to the experimental error. Hence, this is also a The advantage of the instant invention is that;
- It gives a higher thermal output claimed by any other fuel additive,
- It has a unique composition which not similar to any other invention,
- It has multiple beneficial aspects like temperature enhancement,
emission reduction and as well as trace metal content reduction in the
fly ash,
No such additive was found having all these three aspects in a single component,
The instant invention will now be explained with the help of following examples.
Example 1
Preparation of Fuel Additive Composition-Batch of 10000 kg:
4.4 - 4.75 kg of non-metallic salt portion of the additive along with 100-500 g of the metallic salt without any moisture content were mixed in a vessel with the help of a mechanical mixture with stirring to form a homogenous mixture. Then 300-250 g of organic support was gradually added with continuous mixing under atmospheric conditions. The process continued for sufficient time to ensure complete mixing of the ingredients. The completed process was shut down and the composition mixture was pumped into packets. Samples were collected. If desired for the specific applications the composition is diluted before packing it up to meet certain requirements.
Example 2
Supertherm K2R was added to the coal by a laboratory designed screw feeder for feeding to the combustor where pulverized coal is to be burnet. The aqueous solution of the additive with 85-95 % of a non-metallic salt from the elements of group VA-VIIA, 2-10% of metallic salt of group IA-IIIA of elements, 3-5% of an organic support selected from amines was made by dissolving the additive in water. Then it was mixed with desired amount of pulverized coal at a ratio of 500g/ton to get enhanced efficiency. Prior to it the measurement for NOX emission for pure coal (without additive) was measured using Thermoelectron High Level NOx gas analyzer. The emission data obtained prior to and following the feed of the additive can be seen in Figure-4 in the result
discussion part showing that in case of additive the emission of NOx was reduced. During measurement the combustor was operating almost at the same conditions. Sampling was continuous during measurement, the data shown in the following figure cover a running period of approximately quarter of an hour period.
Example 3
Aqueous solution of the Supertherm K2R at a ratio of 500g/ton was added by weight to the coal by mechanical spraying. Then the coal sample was dried for a sometime under sunlight to reduce the moisture effect added by spraying of the aqueous solution. It was fed to an initially heated combustor (see fig-2) with the supply of air and feeder arrangement. The temperature was measured using a Masibus digital temperature measuring system. The initial temperature of the combustor at both the time was maintained around 875K. When the ordinary coal (coal without additive) was added the temperature became close to 915K. But after the coal with K2R was fed the temperature increased much higher than the earlier case. In both the cases the temperature reading was considered after 5-7 minutes after coal feeding i.e. when the temperature fluctuation was not there. The average temperature enhancement was about 12-15% more in case coal without additive, as it can be seen from the initial data in figure 3.
Field of Invention:
The present invention relates to a fuel additive composition to enhance thermal output, reduce NOX emission and decreasing concentration of hazardous trace metal in fly ash during coal combustion.
Background Of invention:
Most of our energy demand is met by the thermal power plants, which use coal for their operation. Coal has become an important source of energy in this century and it will continue to be prime source for the coming hundred years though its depletion is imminent. The growing energy demand for a rapidly developing country like India, it has become imperative to look at other prospects of energy production and saving. In India, the demand for production and consumption of coal are very huge. Most of the raw coals mined every year are directly used as fuels. Hence, it is very important and necessary to improve the burning of coal so as to save energy and minimize environmental pollution. Generally, high efficiency and less pollutant generation the mark of a quality coal burning.
In addition, the utilization of low-rank coals, which occupy many lands and pollute environment, is a problem that has to be solved. Among all kinds of methods of achieving the above purposes, the use of additives in the process of coal burning is an effectual one. In recent years, the application of combustion additives is picking up quickly; coal mixed with the additives are being used as fuels in electricity generation, cement industry and civil utilization in many developed countries like China, USA etc.
The major portion of power generation in India is also being done using coal. However, high ash content in Indian coal and inefficient combustion technologies contribute to India's emission of air particulates and other trace gases like high levels of NOX, huge quantities of fly ash which become a problem for disposal etc. that are responsible for the greenhouse effect, polluting the local as well as global environment.
Presently, increasing coal use or blending Indian coal with imported coal of higher calorific value (for increasing electricity production) needs to be carefully addressed through viable technological options. Oxidation of nitric oxide (NO) discharged in combustion products forms nitrogen dioxide (N02) in the atmosphere is another problem. These oxides of nitrogen are responsible for the formation of photochemical smog.
As a consequence of the increased emphasis on the environmental impacts of energy production world wide, there is now search for the improved technologies for combustion and design parameters. In order to reduce these hazardous emissions with increased the thermal efficiency of the combustion system is one of the ways out of this precarious situation. The use of additives is one such way of improving the combustion characteristics of a process. But fundamental research works on the burning characteristics of coals doped with

the coal-burning additives should be carried out in order to give scientific basis to the application of the coal-burning additives.
W006088462A1 discloses a mixed alcohol formulas used as a fuel additive in gasoline, diesel, jet fuel, aviation gasoline, heating oil, bunker oil, coal, petroleum coke or as a neat fuel in and of itself. The mixed alcohols formulations comprises of CrCs alcohols, or in the alternative, CrCs alcohols or higher Crdo alcohols in order to boost energy content. The CrC5 mixed alcohols contain more ethanol than methanol with declining amounts of propanol, butanol and pentanol. CrC8 mixed alcohols contains the same, with declining amounts of hexanol, heptanol and octanol. CrCio mixed alcohols contains the same, with declining amounts of nananol and decanol. Synthetically produced mixed alcohol formulas feature higher octane and energy densities than either MTBE or fermented grain ethanol; more stable Reid Vapor Pressure blending characteristics; and increased solubility effects on condensate water. The primary benefits of mixed alcohols are increased combustion efficiencies, reduced emissions profiles and low production costs.
W004104141A2 a US20060218853A1 teaches a fuel additive composition for preventing scaling, excluding of soot, clinker and sludge, and controlling flame in combustion apparatus. Said composition comprising hydrogen peroxide, an amine-based stabilizer, borax, and sodium hydroxide. The composition is added to such fuel as coal, oil, and gas to facilitate combustion and remove impurities in a combustion apparatus, thereby improving thermal efficiency, and it reduces discharge of noxious gases such as SOX, NOX, and CO.
US7101493 discloses a composition for suppressing coal dust includes a metal-containing compound, such as an organo-manganese, that provides the additional benefit of being a combustion improver. The organometallic compound is mixed with any appropriate dust suppressant liquid. The organometallic compound may include methylcyclopentadienyl manganese tricarbonyl.
W002077132A1, EP1375631A4 and US20040079925A1 teaches a fuel additive is directed to preventing slagging, a phenomenon caused by the ash in a fuel particularly during the combustion of a fuel having such a large ash content as is typically found in coal or oil coke, for example. It is formed of a composition having one or more compounds selected from among aluminum compounds, silica compounds, titanium compounds and zirconium compounds invariably of the form of ultrafine particles having a particle diameter in the range of 3 to 200 nm and no less than 2 wt. % of an alkali metal (R = Na or K) compound as reduced to the R20 concentration dispersed in a stable state in water and/or oil. When a liquid fuel oil and/or a solid fuel is made to incorporate the fuel additive therein and then subjected to combustion, the deposited ash can be easily peeled and shed from the surface of the furnace wall or the water pipes.

CN1724621A discloses a fuel coal additive. The main feature is that mixes the salt combustion adjuvant and calcium oxide absorbent as the ratio of 4-10%:96-90%. The invention uses the combustion supporting and catalysis of Na and Cl that could be decomposed from melt salt. The C02 from burning calcium oxide could absorb the S02 from burning coal and finally form CaCO.-). Thus, the aim of benefit for the environment would be achieved.
CN1710036A teaches a fuel combustion-reinforcing agent. Said invention involves a fuel additive, especially a kind of high-efficient fuel burning-assistant to solve the defect of present fuel additive with unsatisfactory result and low energy-conserving efficiency. A high-efficient fuel fire assistant, it in weight to proportion is: oxalate 40-50%, 2-ethylhexanol 25-35%, dimethylether 1-5%, tert-butylmethylether 2-10 ether, three contract triethylamine 2-8%, triethylamine 2-10%, and amylnitrate 0-5%, C10H10Fe 2-8%, Ci2.16H25.33S03Na 1-5%, special oxygen 0.2-1%. At first, fetch the material according to matching, then mix disposing according to the order of matching, join a kind of raw materials each time, need mixing for 3-6 minutes fast.
JP2004083796A2 discloses a fuel additive composed of a composition produced from ultrafine silica sol particles having a particle diameter of 3-200 nm and ultrafine Al(OH)3 particles and/or ultrafine Zr compound particles surface-modified with a surfactant and having a particle diameter of 2-100 nm by dispersing the Al(OH)3 particles and the Zr compound particles in water. The fuel additive is added to a liquid fuel oil or a solid fuel and the fuel is burned.
JP2004018704A2 discloses a fuel additive comprises a composition having one or more of an Al compound, an Si compound, a Ti compound, and a Zr compound, each in a super-fine particulate having a particulate size of 3-200 nm, and a water-soluble explosive compound dissolved or dispersed in water.
CN1090316A teaches an effective energy-saving oil fuel additive. An efficient energy-saving additive for fuel oil features its 32 components such as coal tar, alcohol, acetone, benzene, rape oil, glycerin, MoS2, graphite, Teflon etc. Its advantages include combustion assistance, resisting detonation, friction reduction and less carbon collection. Fuel saving rate is up to 10-30%.
JP62265391A2 teaches a fuel additive comprising a finely divided iron oxide which is laminar or annular i.e., consisting of laminate having a through hole in the center thereof, is mixed either with a machine oil, a dispersing agent, a stabilizing agent (e.g., sorbitan mono-oleate), etc., to give an oil-slurry fuel additive or with water, ethylene glycol, a stabilizing agent, etc. to give a water- slurry fuel additive. This oil-slurry or water-slurry fuel additive contains iron oxide particles having a laminar form free of sharp edges; therefore, the incorporation of this additive into a fuel even in a large amount will neither cause a pump, a burner tip, etc., to wear out nor cause settling of the additive.

Most of the compositions of prior art use hazardous transitional metal elements, which are emitted as by product during the combustion and increase the concentration of hazardous trace metal in fly ash. Secondly the compounds used in the additives are quite expensive.
Most of the prior art compositions have two components out of which one is adjuvant. Basically single component catalyst. Further, the adsorbent which is probably the CaCOS produces C02 and that somehow manages to consume in the due course. It has no effect on temperature enhancement or on trace metal concentration.
Present invention provides a fuel additive composition, which obviates the drawbacks of the prior art and has increased combustion efficiencies, reduced emissions profiles and low production costs. It also has notable economical benefit and social benefit.
Summary of the Invention:
Present invention relates to a fuel additive composition to enhance thermal output, reduce NOX emission and decreasing concentration of hazardous trace metal in fly ash during coal combustion comprising:
85 to 95 % of a non-metallic salt selected from the elements of group VA to VIIA,
2 to 10% of metallic salt selected from the group of elements from IA to
IMA,
3 to 5 % of an organic support selected from the group of amines.
The non-metallic salts are selected from ammonium salts.
The additive composition of the present invention comprises one or more metal salts. The cationic part of metallic salt is selected from sodium, potassium, beryllium, magnesium and aluminum preferably sodium. The anionic part of the metal salt is selected from nitrate, chloride, bromide, iodide and sulphate.
The organic support is an aliphatic amine preferably hexamine.
The present invention further provides a coal composition obtained by spraying 1% aqueous solution of fuel additive to enhance thermal output, reduce NOX emission and decreasing concentration of hazardous trace metal in fly ash during coal combustion.
Description of the drawings:
Fig. 1: Schematic of the Experimental Set up
Fig. 2: Detailed outline of the Test Coal Combustor
Fig. 3: Flue Gas Temperature Variation with Coal Feed Rate

Fig. 4: Variation of NO Emission level with Coal Feed Rate Detailed description of the Invention:
The objective of the instant invention is to increase combustion efficiencies, reduced emissions profiles and low production costs. To achieve the said objective the invention provides a fuel additive composition to enhance thermal output, reduce NOX emission and decreasing concentration of hazardous trace metal in fly ash during coal combustion comprising:
85 to 95 % of a non-metallic salt selected from the elements of group VA to V1IA,
2 to 10% of metallic salt selected from the group of elements from IA to
MIA,
3 to 5 % of an organic support selected from the group of amines.
The instant invention has three components and all three are necessary for an efficient combustion. Further, it does not contain any CaC03 proportion therefore, leads to lesser emission of C02 and NOx. Also the instant invention has substantial effect on trace metal as well as on thermal output of the combustion system.
The studies were carried to find out the effect of the combustion additive Supertherm K2R on the pulverized coal combustion. The following conclusions can be drawn from the above study.
1. The additive has substantial role in enhancing the thermal out put of the
combustion system in test conditions.
2. There is a temperature increase in the range of 12-15% when the
combustor is operated in the low feed conditions, which further widens
as the feed rate increases.
3. There is a definite role in the heat generation during a combustion
process for pulverized coal combustion.
4. It also marginally reduces emission of highly polluting gases like Nitric
Oxide (NO).
5. It has a profound effect in reducing the trace metal quantities in the fly
ash generated from the coal mixed with this additive.
Figure 1 shows the schematic diagram of the experimental set up used for the study. The combustor was an insulated cylindrical tube of diameter 72 mm and of length 1.2 meter placed horizontally. A thickness of 50-70 mm of insulating material was placed outside the combustor to check the radiative heat loss to the surrounding. Dry air was supplied to the combustor in two stages from the compressor. The primary air was supplied through the coal container which carried weighed amount of pulverized coal. Secondary tangential air along with LPG fuel was used for initial heating of the combustor. The temperature

measuring system was fitted to the burner exit to measure the flue gas temperature. The emission was measured using gas analyzer connected to the water-cooled sampling probe. The burnt ash was tested for trace metal concentrations using the Atomic Absorption Spectroscopy (AAS). The detail description of the test procedure has been given later in the experimental procedure section.
TEST BURNER:
The structure of the pulverized burner indigenously developed to suit the test conditions of the furnace was developed in our laboratory. The burner is designed to have a coal combustion capacity of about 5kg per hour. The shape of the pulverized coal combustor is cylindrical SS tube placed horizontally during combustion. Figure 2 shows the enlarged diagram of the combustor, which is of 72 mm diameter and 1.2 meter long. There are two air supply ports in the burner namely Primary air, which comes along with coal to the burner. The secondary port for air is a tangential one, which helps in the better mixing of coal with air and helps to increase the residence time to insure better combustion.
EXPERIMENTAL METHOD AND MEASUREMENT:
In the initial stages of the experiment, LPG was supplied along with tangential air to warm the combustor, which will help the initiation of coal burning. The LPG supply was stopped after the combustor reached sufficiently high temperature. Then coal was supplied through primary air supply port by discontinuing the LPG supply and tangential air supply was reduced. Flue gas temperature measurement was taken after the temperature raised to a maximum and less fluctuation was observed through the temperature scanner connected to two K type thermocouples attached to the burner exit. Then the measurement for emission was done through a water-cooled sample handling system which supplied cooled flue gas to the NOX analyzer based on Chemiluminescence based principle. During the process the ratio of primary to secondary air was kept at 100-40 liter/min. Then the time for entire process was measured and the coal left in the container was measured. The quantity of ash left in the combustor was also measured. Few grams of this ash were subjected to acid digestion and the trace metal content was measured using the standard procedure with the help of Atomic Absorption Spectroscopy (AAS). Two separate experiments were conducted one with pure coal and other with the additive to study the effect of the additive, Supertherm K2R on trace metal contents. The detailed discussions of the results are as follows.
EXPERIMENTAL RESULTS:
The findings of the study have been characterized in terms of flue gas temperature, emission from the coal combustion and trace metal concentration

in ash generated during the combustion. The detailed description has been laid out in the subsequent section of the report.
FLUE GAS TEMPERATURE:
The measured flue gas temperature is plotted by taking into consideration of the coal feed rate to the combustor in Fig. 3. It can be seen from the plot that the temperature of the flue gas increases as the coal feed rate is increased. It happens to the pure coal as well as coal mixed with the additive. It can also be seen that, there is a substantial increase in the flue gas temperature when the coal is mixed with the catalyst. The catalytic and accelerating effects of Supertherm K2R on the burning coals increased the temperature of the system in range of 12-15% under test conditions, which may be due the better oxidation of the fuel. This indicates that there is remarkable enhancement in heat generation capacity of the fuel is due to the additive.
POLLUTANT EMISSION FROM THE COMBUSTION:
Due to the stringent emission norms coming up time to time, we thought of seeing the effect of the Supertherm K2R on emission during the combustion. The emission for one of the important pollutants like NO was done by gas analyzer and the data has been plotted out in Fig 4. The variation for NO emission level is plotted against the coal feed rate in Fig. 4. It is observed that the NO emission level increased with the increase in the coal feed rate for both the cases. However, a decrease in NO emission level was observed when additive was mixed with the coal. A variation in reduction ranging from 5% to 9% was observed when the feed rate was doubled from 15 g/min to 30 g/min.
CONCENTRATION OF TRACE METALS IN THE FLY ASH:
The trace metal content for seven metals were measured from both the fly ash generated by the combustion of simple coal as well as the Supertherm added coal. The ash samples were acid digested and subjected to the analysis as per the standard methods with the help of Atomic Absorption Spectroscopy (AAS). The data has been provided in Table-1. It can be seen that in case of five metals there was sufficient degradation in the metal concentration. In case of the other two metals there was a negligible increase in the percentage of metal, which can be attributed to the experimental error. Hence, this is also a The advantage of the instant invention is that;
- It gives a higher thermal output claimed by any other fuel additive,
- It has a unique composition which not similar to any other invention,
- It has multiple beneficial aspects like temperature enhancement,
emission reduction and as well as trace metal content reduction in the
fly ash,
No such additive was found having all these three aspects in a single component,
The instant invention will now be explained with the help of following examples.
Example 1
Preparation of Fuel Additive Composition-Batch of 10000 kg:
4.4 - 4.75 kg of non-metallic salt portion of the additive along with 100-500 g of the metallic salt without any moisture content were mixed in a vessel with the help of a mechanical mixture with stirring to form a homogenous mixture. Then 300-250 g of organic support was gradually added with continuous mixing under atmospheric conditions. The process continued for sufficient time to ensure complete mixing of the ingredients. The completed process was shut down and the composition mixture was pumped into packets. Samples were collected. If desired for the specific applications the composition is diluted before packing it up to meet certain requirements.
Example 2
Supertherm K2R was added to the coal by a laboratory designed screw feeder for feeding to the combustor where pulverized coal is to be burnet. The aqueous solution of the additive with 85-95 % of a non-metallic salt from the elements of group VA-VIIA, 2-10% of metallic salt of group IA-IIIA of elements, 3-5% of an organic support selected from amines was made by dissolving the additive in water. Then it was mixed with desired amount of pulverized coal at a ratio of 500g/ton to get enhanced efficiency. Prior to it the measurement for NOX emission for pure coal (without additive) was measured using Thermoelectron High Level NOx gas analyzer. The emission data obtained prior to and following the feed of the additive can be seen in Figure-4 in the result
discussion part showing that in case of additive the emission of NOx was reduced. During measurement the combustor was operating almost at the same conditions. Sampling was continuous during measurement, the data shown in the following figure cover a running period of approximately quarter of an hour period.
Example 3
Aqueous solution of the Supertherm K2R at a ratio of 500g/ton was added by weight to the coal by mechanical spraying. Then the coal sample was dried for a sometime under sunlight to reduce the moisture effect added by spraying of the aqueous solution. It was fed to an initially heated combustor (see fig-2) with the supply of air and feeder arrangement. The temperature was measured using a Masibus digital temperature measuring system. The initial temperature of the combustor at both the time was maintained around 875K. When the ordinary coal (coal without additive) was added the temperature became close to 915K. But after the coal with K2R was fed the temperature increased much higher than the earlier case. In both the cases the temperature reading was considered after 5-7 minutes after coal feeding i.e. when the temperature fluctuation was not there. The average temperature enhancement was about 12-15% more in case coal without additive, as it can be seen from the initial data in figure 3.

We claim:
1. The fuel additive composition to enhance thermal output, reduce
NOX emission and decreasing concentration of hazardous trace
metal in fly ash during coal combustion comprising:
- 85 to 95 % of a non-metallic salt selected from the elements of
group VA to VIIA,
- 2 to 10% of metallic salt selected from the group of elements
from IA to I HA,
- 3 to 5 % of an organic support selected from the group of
amines.

2. The fuel additive composition as claimed in claim 1 wherein the
non-metallic salts are selected from ammonium salts.
3. The fuel additive composition as claimed'in claim 1 wherein the
cationic part of metallic salt is selected from sodium, potassium,
beryllium, magnesium and aluminum preferably sodium.
4. The fuel additive composition as claimed in claim 1 wherein the
anionic part of the metal salt is selected from nitrate, chloride,
bromide, iodide and sulphate.
5. The fuel additive composition as claimed in claim 1 wherein the
organic support is an aliphatic amine preferably hexamine.
6. The fuel additive composition as claimed in claim 1 wherein one
or more metal salts are added to obtain the composition.
7. A coal composition obtained by spraying 1% aqueous solution of
fuel additive as claimed in any of the preceding claim to enhance
thermal output, reduce NOX emission and decreasing
concentration of hazardous trace metal in fly ash during coal
combustion.