JP2011140919A - Fuel supply method for combustion apparatus and combustion apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To supply an alcoholic fuel by a method appropriate for supplying the fuel to the combustion chamber of a combustion apparatus. <P>SOLUTION: The combustion apparatus includes the combustion chamber 2 for burning a main fuel 1, a mixing means 5 for mixing the alcoholic fuel 4 with water 3 for suppressing thermal NOx, and an injection means 6 for injecting the water 3 mixed with the alcoholic fuel 4 singularly or with the main fuel 1 into the combustion chamber 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel supply method for combustion equipment and a combustion equipment. More specifically, the present invention relates to a method for supplying alcohol-based fuel in a combustion apparatus that suppresses the generation of thermal NOx by supplying water or steam to the combustion gas of the main fuel to lower the temperature of the combustion gas and combustion using the same. It relates to equipment.

  In order to reduce the emission of carbon dioxide, which is a warming gas, the use of alcohol-based fuels, such as bioethanol, is being studied in combustion equipment such as gas turbines, diesel engines, and boilers. For example, Patent Document 1 proposes a diesel fuel in which an alcohol fuel is mixed with light oil. This diesel fuel contains diesel oil for diesel engines as a main component, and is a mixture of isopropyl alcohol, normal propyl alcohol, isobutyl alcohol, and sensary butyl alcohol. In Patent Document 2, as an alternative fuel to light oil, triacylglycerol, monoacylglycerol and alcohol are mixed, and the viscosity of a microemulsion in which alcohol (dispersed phase) is dispersed in triacylglycerol (continuous phase) is mono A natural fat fuel reduced with acylglycerol (surfactant) has been proposed.

  By using such a diesel fuel or an alternative fuel in a diesel engine in the same manner as ordinary light oil, it becomes possible to supply an alcohol fuel to the combustion chamber of the diesel engine.

JP 2006-37064 A JP-A-11-279572

  However, diesel fuel in which alcohol is mixed with light oil is easy to separate because the affinity between light oil and alcohol is inferior, and it is difficult to maintain a uniformly mixed state. Therefore, actual use is difficult. Further, although the alternative fuel can maintain a dispersed state of the alcohol as compared with the diesel fuel, there is a risk that the alcohol may be separated when left for a long time, so that it is difficult to actually use the alternative fuel. That is, any of the above fuels has a problem in actual use, and it is difficult to supply alcohol-based fuel to the engine in this way.

  It is an object of the present invention to provide a fuel supply method of alcohol-based fuel suitable for actual use and a combustion device using the same.

  In order to achieve this object, the invention described in claim 1 is directed to a fuel supply method for a combustion apparatus for supplying water or steam for suppressing thermal NOx to the combustion gas of the main fuel. The system fuel is mixed and injected into the combustion chamber together with the main fuel or alone.

  Therefore, the alcohol fuel is supplied into the combustion chamber as an alcohol aqueous solution or its vapor and burned. The combustion gas of the main fuel is cooled by the alcohol aqueous solution injected together with the main fuel or independently, that is, separately from the main fuel and the combustion air, or moisture in the steam thereof, and the generation of thermal NOx is suppressed. Is done. Since alcohol-based fuel is easily dissolved in water, it can be injected as an aqueous alcohol solution or its vapor in the same manner as injecting water or water vapor for suppressing thermal NOx. Moreover, the alcohol concentration of the alcohol aqueous solution or the vapor | steam to inject becomes low by mixing alcohol fuel with water or water vapor | steam.

  In the fuel supply method for a combustion device according to claim 2, the alcohol concentration in water or water vapor mixed with alcohol-based fuel is less than 60% by weight. Therefore, the prepared aqueous alcohol solution can be injected into the combustion chamber in a state of low alcohol concentration that is not regulated by the Fire Service Law.

  According to a third aspect of the present invention, there is provided a fuel supply method for combustion equipment, wherein an alcohol aqueous solution having an alcohol concentration of less than 60% by weight is mixed with water or water vapor. Therefore, all alcohol aqueous solutions to be handled can have a low alcohol concentration that is not regulated by the Fire Service Law.

  Further, as in the fuel supply method for combustion equipment according to claim 4, the alcohol-based fuel is preferably derived from a plant in order to reduce carbon dioxide emissions. Examples of plant-derived alcohol fuels include lower alcohols such as ethanol, methanol, butanol, propanol, isopropyl alcohol, ethylene glycol, and glycerin.

  In addition, as in the fuel supply method for combustion equipment according to claim 5, the alcohol-based fuel is preferably bioethanol in order to reduce carbon dioxide emissions.

  Furthermore, the combustion apparatus according to claim 6 is provided with a combustion chamber for burning main fuel, mixing means for mixing alcohol-based fuel with water or steam for suppressing thermal NOx, and water or steam mixed with alcohol-based fuel. Injecting means for injecting into the combustion chamber together with the main fuel or alone is provided.

  Therefore, the alcohol-based fuel is mixed with water or water vapor for suppressing thermal NOx by the mixing means, supplied as an alcohol aqueous solution or its vapor from the injection means into the combustion chamber, and burned. The combustion gas of the main fuel is cooled by the alcohol aqueous solution injected together with the main fuel or independently, that is, separately from the main fuel and the combustion air, or moisture in the steam thereof, and the generation of thermal NOx is suppressed. Is done. Since alcohol-based fuel is easily dissolved in water, it can be injected from the injection means as an aqueous alcohol solution or its vapor in the same manner as water or water vapor for suppressing thermal NOx is supplied, and supply of alcohol-based fuel into the combustion chamber Is easy. By mixing the alcohol fuel with water or water vapor, it is possible to reduce the alcohol concentration of the aqueous alcohol solution or the vapor thereof injected from the injection means.

  In the fuel supply method for the combustion device according to claim 1 and the combustor according to claim 6, the alcohol fuel is mixed with water or steam for thermal NOx suppression and supplied to the combustion chamber as an alcohol aqueous solution or its vapor. The alcohol-based fuel can be reliably burned in the combustion chamber, and the alcohol-based fuel can be used as an auxiliary fuel to supplement the main fuel. That is, when using an alcohol fuel in a combustion device, for example, it is conceivable to prepare a fuel in which an alcohol fuel is mixed with the main fuel and use it. However, in this case, it is necessary to consider the compatibility between the main fuel and the alcohol-based fuel, and it is difficult to apply to combustion equipment that uses the main fuel in which the alcohol-based fuel is difficult to dissolve. On the other hand, in the present invention, alcohol fuel is mixed with water or water vapor for thermal NOx suppression and injected into the combustion chamber, so that the alcohol-based combustion equipment that uses fuel that is difficult to mix with alcohol fuel as the main fuel is also used. Fuel can be used.

  Also, since alcohol fuel is mixed with thermal NOx suppression water or water vapor and supplied into the combustion chamber, the alcohol fuel is easily supplied to the combustion chamber and is suitable for combustion. Fuel can be supplied.

  In addition, water or steam for suppressing thermal NOx containing alcohol-based fuel is supplied into the combustion chamber together with or alone with the main fuel, and is supplied separately from the combustion air, thereby reducing the supply amount of the combustion air. This can prevent a reduction in the amount of fuel that can be burned.

  Further, since the flame temperature of the alcohol-based fuel is relatively low, the NOx generation suppressing effect by water or water vapor for suppressing thermal NOx is not so much affected.

  Moreover, since the alcohol-based fuel can be supplied using equipment for injecting water or water vapor for suppressing thermal NOx into the combustion chamber, it can be realized at low cost.

  In the method for supplying combustion equipment according to claim 2, the alcohol concentration of the aqueous alcohol solution supplied to the combustion gas of the main fuel is less than 60% by weight. Explosion-proof equipment required by using is sufficient. That is, the operation in the normal explosion-proof specification without using alcohol fuel can be performed around the combustion chamber.

  In the fuel supply method for combustion equipment according to claim 3, since the alcohol aqueous solution having an alcohol concentration of less than 60% by weight is mixed with water or water vapor for suppressing thermal NOx, the alcohol aqueous solution before mixing is also used by the Fire Service Act. Therefore, consideration for explosion-proofing of the aqueous alcohol solution before mixing can be reduced. Moreover, the alcohol aqueous solution with low alcohol concentration can be used as it is at the time of manufacture.

  Here, like the fuel supply method of the combustion apparatus of Claim 4, it is preferable to use a plant-derived alcohol fuel for the reduction of carbon dioxide emission. Generally, plant-derived alcohol-based fuels are refined at the time of production to increase the alcohol concentration. However, in the present invention, the alcohol-based fuel is diluted with water and used. There is no need to increase it. Therefore, it is possible to simplify the production of the alcohol fuel, and it is possible to use an inexpensive alcohol fuel. Further, by using a carbon-neutral plant-derived alcohol-based fuel, it is possible to prevent new carbon dioxide emissions due to combustion in combustion equipment.

  In addition, as in the fuel supply method for combustion equipment according to claim 5, it is preferable to use bioethanol as the alcohol-based fuel in order to reduce carbon dioxide emissions. By using carbon-neutral bioethanol, it is possible to prevent new carbon dioxide emissions due to combustion in combustion equipment.

It is a schematic block diagram which shows 1st Embodiment of the combustion equipment of this invention. It is sectional drawing of the front-end | tip part of the nozzle which injects prepared alcohol aqueous solution. It is a schematic block diagram which shows 2nd Embodiment of the combustion equipment of this invention. It is a schematic block diagram which shows 3rd Embodiment of the combustion equipment of this invention. It is a schematic block diagram which shows 4th Embodiment of the combustion equipment of this invention. It is a schematic block diagram which shows 5th Embodiment of the combustion equipment of this invention. It is a schematic block diagram which shows 6th Embodiment of the combustion equipment of this invention. It is a graph which shows the relationship between the ratio of ethanol aqueous solution and a main fuel, and the NOx reduction rate, and shows the experimental result conducted by changing ethanol concentration. It is a graph which shows the result of having converted the graph of Drawing 8 into the relation of water / main fuel ratio and NOx reduction rate.

  Hereinafter, the configuration of the present invention will be described in detail based on the best mode shown in the drawings.

  FIG. 1 shows a first embodiment of the combustion device of the present invention. In the present invention, alcohol fuel is mixed with water or water vapor for suppressing the generation of thermal NOx and supplied, and alcohol fuel can be used in combustion equipment that has previously been difficult to apply alcohol fuel. It is what. The combustion equipment mixes the combustion chamber 2 for burning the main fuel 1, the mixing means 5 for mixing the alcohol fuel 4 with water or water vapor (hereinafter referred to as water 3) for suppressing thermal NOx, and the alcohol fuel 4. Further, an injection means 6 for injecting the water 3 into the combustion chamber 2 together with the main fuel 1 or alone is provided. That is, the combustion device has means for supplying water 3 to the combustion gas of the main fuel 1 and reducing the temperature of the combustion gas to suppress the generation of thermal NOx. The alcohol 3 is mixed with the water 3, The alcohol-based fuel 4 is burned by supplying the prepared aqueous alcohol solution to the combustion gas. In this embodiment, the prepared alcohol aqueous solution is injected into the combustion chamber 2 alone, that is, separately from the main fuel 1 and the combustion air 8, and the water / alcohol supply system 9 is connected to the injection means 6. It is an injection nozzle.

  The combustion chamber 2 is supplied with main fuel 1 and combustion air 8 and burned. The main fuel 1 may be burned by supplying the entire amount from one nozzle or a plurality of nozzles at a time into the combustion chamber 2 (one-stage combustion), or divided into a plurality of stages along the flow direction of the combustion gas. And may be gradually burned (multistage combustion). Similarly, the combustion air 8 may be supplied to the combustion chamber 2 at a time from one nozzle or a plurality of nozzles and burned, or divided into a plurality of stages along the direction in which the combustion gas flows. May be supplied and gradually burned.

  Applicable combustion equipment is not limited by the type of main fuel 1. That is, the present invention can be applied to combustion equipment that uses either liquid fuel or gaseous fuel as the main fuel 1, and can also be applied to combustion equipment that uses solid fuel. Here, as the liquid fuel, for example, fossil fuels such as naphtha, light oil, kerosene, A heavy oil, C heavy oil, crude oil and the like, bio-derived plant crude oil such as rapeseed oil, cottonseed oil and palm oil, animal properties such as fish oil, milk fat and beef tallow Examples include oils obtained by methyl esterification of crude oil, vegetable crude oil and animal crude oil. Examples of the gaseous fuel include natural gas, LP gas, butane gas, carbon monoxide, hydrogen gas, blast furnace gas, coal, biomass, gasified gas such as distillation residue oil, and the like. Examples of the solid fuel include pulverized coal, charcoal, and wood pellets. Further, it can be applied not only to combustion equipment using the main fuel 1 in which the alcohol-based fuel 4 is easily dissolved, but also to combustion equipment using the main fuel 1 in which the alcohol-based fuel 4 is difficult to dissolve or does not dissolve. .

  The water / alcohol supply system 9 mixes a liquid or gaseous alcohol-based fuel 4 with water 3 to prepare an aqueous alcohol solution or its vapor and supplies it to the injection means 6. An alcohol aqueous solution is prepared by mixing the alcohol-based fuel 4, and the alcohol aqueous solution (hereinafter referred to as a prepared alcohol aqueous solution) is supplied to the injection means 6.

  The water / alcohol supply system 9 includes a mixing means 5 for mixing the water 3 and the alcohol fuel 4, a water tank 10 for storing the water 3, and a water pump 11 for supplying the water 3 in the water tank 10 to the mixing means 5. The water amount adjusting means 12 for adjusting the amount of water supplied from the water pump 11 to the mixing means 5, the fuel tank 13 for storing the alcohol fuel 4, and the fuel for supplying the alcohol fuel 4 in the fuel tank 13 to the mixing means 5 A pump 14 and fuel amount adjusting means 15 for adjusting the flow rate of the alcohol-based fuel 4 supplied from the fuel pump 14 to the mixing means 5 are provided. In this embodiment, the alcohol-based fuel 4 is stored in the fuel tank 13 in the state of an alcohol aqueous solution 7 having a low alcohol concentration. However, the alcohol-based fuel 4 is not necessarily in the state of the alcohol aqueous solution 7, and the alcohol-based fuel 4 can be stored and used by preparing explosion-proof equipment.

  The mixing means 5 is, for example, a collecting pipe that joins the flow path 17 of the alcohol-based fuel 4 (alcohol aqueous solution 7) to the flow path 16 of the water 3. However, the present invention is not limited to the collecting pipe, and any pipe that can mix the aqueous alcohol solution 7 with the water 3 can be used.

  The water amount adjusting means 12 includes, for example, a flow rate adjusting valve 12a that adjusts the flow rate in the flow channel 16, and a flow meter 12b that measures the flow rate in the flow channel 16, and the flow rate adjusting valve 12a is a flow rate measured by the flow meter 12b. The flow rate is adjusted so that becomes a predetermined target value. Further, the fuel amount adjusting means 15 includes, for example, a flow rate adjusting valve 15a for adjusting the flow rate in the flow path 17 and a flow meter 15b for measuring the flow rate in the flow path 17, and the flow rate adjusting valve 15a is measured by the flow meter 15b. The flow rate is adjusted so that the obtained flow rate becomes a predetermined target value. The flow rate adjusted water 3 and alcohol aqueous solution 7 are mixed by the mixing means 5 and become a prepared alcohol aqueous solution having a preset alcohol concentration while flowing to the injection means 6. That is, the flow rate of water 3, the flow rate of alcohol aqueous solution 7, and the alcohol concentration are determined so that the flow rate and alcohol concentration of the prepared alcohol aqueous solution become predetermined values, respectively. The prepared alcohol aqueous solution is pumped to the injection means 6 by the pressures of the water pump 11 and the fuel pump 14 and injected into the combustion chamber 2.

  The prepared alcohol aqueous solution is preferably injected toward a region where the temperature of the combustion gas of the main fuel 1 is highest (hereinafter referred to as a high temperature region). By doing in this way, the maximum temperature of combustion gas becomes low and generation | occurrence | production of thermal NOx can be suppressed most effectively. However, the supply position of the prepared alcohol aqueous solution is not limited to this, and may be any position where the effect of lowering the temperature of the combustion gas can be obtained even if it is out of the high temperature region.

  The injection nozzle as the injection means 6 may be integrated with a fuel nozzle for injecting the main fuel 1 into the combustion chamber 2 or may be a separate one. Further, when the fuel nozzle and the injection nozzle are separated, the injection nozzle may be integrated with the nozzle that supplies the combustion air 8 into the combustion chamber 2 or may be separate.

  FIG. 2 shows an injection nozzle integrated with a fuel nozzle. An injection port 22 for injecting the main fuel 1 is provided at the center of the tip of the nozzle, and a plurality of injection ports 23 for injecting the prepared alcohol aqueous solution 24 are arranged at predetermined intervals on the circumference centering on the injection port 22. Is provided. The prepared alcohol aqueous solution 24 is injected toward the combustion gas 25 of the main fuel 1 injected from the injection port 22.

  Any alcohol-based fuel 4 that can be dissolved in water 3 can be used. For example, lower alcohols such as ethanol, methanol, butanol, propanol, isopropyl alcohol, ethylene glycol, and glycerin can be used. Here, in order to reduce carbon dioxide emission, the alcohol-based fuel 4 is preferably derived from a plant. The alcohol-based fuel 4 derived from plants has an increased alcohol concentration by refining at the time of manufacture. However, in the present invention, the alcohol-based fuel 4 is diluted with water and used. Therefore, it is necessary to bother the alcohol concentration of the alcohol-based fuel 4 at the time of manufacture. The production of the alcohol-based fuel 4 can be simplified. In order to reduce carbon dioxide emissions, the alcohol fuel 4 is preferably bioethanol. By using carbon neutral bioethanol, new carbon dioxide emissions due to combustion can be prevented. However, a plant-derived alcohol fuel 4 or an alcohol fuel 4 other than bioethanol may be used.

  In this embodiment, the alcohol concentration of the prepared alcohol aqueous solution ejected from the ejection means 6 is less than 60% by weight. By adjusting the alcohol concentration to less than 60% by weight, the prepared alcohol aqueous solution is not subject to the regulations of the Fire Service Act, and the explosion-proof equipment around the combustion chamber 2 can be simplified. However, the alcohol concentration of the prepared alcohol aqueous solution does not necessarily need to be less than 60% by weight, and an explosion-proof facility is required, but the alcohol concentration may be 60% by weight or more.

  In the present embodiment, in the water / alcohol supply system 9, an alcohol aqueous solution 7 having an alcohol concentration of less than 60 wt% is used as the alcohol fuel 4 mixed with the water 3. That is, the aqueous alcohol solution 7 having an alcohol concentration of less than 60% by weight is stored in the fuel tank 13. For example, in the production of a plant-derived alcohol fuel 4, such as ethanol, the alcohol concentration is low simply by saccharifying the raw material and fermenting, and the alcohol concentration is increased by repeating distillation. This distillation process requires a large amount of energy, which causes an increase in manufacturing costs and an increase in carbon dioxide emissions. In this embodiment, since the alcohol fuel 4 having a low concentration is used, it is possible to use the alcohol fuel 4 that is not distilled or reduced in the number of distillations, thereby reducing costs and reducing carbon dioxide emissions. be able to.

  Next, the fuel supply method for the combustion apparatus of the present invention will be described. A fuel supply method for combustion equipment (hereinafter simply referred to as a fuel supply method) is to supply thermal NOx-suppressing water or water vapor (water 3) to the combustion gas of the main fuel 1. 4 is mixed and injected into the combustion chamber 2 alone.

  When the water pump 11 and the fuel pump 14 of the water / alcohol supply system 9 are operated, the water 3 whose flow rate is adjusted by the water amount adjusting means 12 and the aqueous alcohol solution 7 whose flow rate is adjusted by the fuel amount adjusting means 15 are supplied to the mixing means 5. And mixed to prepare an aqueous alcohol solution (prepared alcohol aqueous solution). This prepared alcohol aqueous solution is supplied to the injection means 6 by the pressure applied by the water pump 11 and the fuel pump 14, and is injected into the combustion chamber 2 and burned. Since the alcohol fuel 4 is easily dissolved in the water 3 and the prepared alcohol aqueous solution can be handled in the same manner as the water for suppressing thermal NOx, the alcohol fuel 4 can be easily supplied into the combustion chamber 2.

  The injection means 6 is provided toward the high temperature region of the combustion gas of the main fuel 1, and the injected prepared alcohol aqueous solution is supplied to the high temperature region of the combustion gas. The high temperature region of the combustion gas is cooled by the water 3 in the prepared alcohol aqueous solution, and the generation of thermal NOx is suppressed.

  Moreover, the alcohol fuel 4 in the prepared alcohol aqueous solution is combusted by the combustion gas. The flame temperature of the alcohol fuel 4 is relatively low. Therefore, the temperature rise of the combustion gas due to the combustion of the alcohol-based fuel 4 is small, and the effect of suppressing the generation of thermal NOx by the water 3 injected together with the alcohol-based fuel 4 is not so much harmed. That is, comparing the temperature rise due to the alcohol-based fuel 4 and the temperature drop due to the water 3, the influence of the temperature drop due to the water 3 is greater, and the generation of thermal NOx can be effectively suppressed.

  In this embodiment, since the alcohol fuel 4 is supplied separately from the main fuel 1, the alcohol fuel 4 is supplied into the combustion chamber 2 even if the main fuel 1 is difficult to dissolve the alcohol fuel 4. And can be burned well.

  Further, for example, in a diesel engine that self-ignites the fuel, it is difficult to use the alcohol-based fuel 4 having low self-ignitability as the main fuel 1, but in the present invention, the combustion gas of the self-ignited diesel fuel (main fuel 1) The alcohol-based fuel 4 can be burned by injecting the prepared alcohol aqueous solution. Therefore, it is possible to use the alcohol-based fuel 4 for a diesel engine.

  In the present invention, since the alcohol fuel 4 is used, the amount of the main fuel 1 used can be reduced accordingly.

  Further, according to the present invention, the prepared alcohol aqueous solution is supplied alone into the combustion chamber 2 and is supplied separately from the combustion air 8, so that the supply of the combustion air 8 into the combustion chamber 2 is provided. It is possible to prevent a reduction in the amount of fuel that can be burned without reducing the amount.

  The present invention is applicable to any combustion equipment having means for injecting water 3 toward the combustion gas of the main fuel 1. For example, the present invention can be applied to combustion equipment such as a gas turbine, a diesel engine, a boiler, a gas engine, and a heating burner such as a hot stove burner, but is not limited thereto.

  For example, when applied to a gas turbine or a boiler, the prepared alcohol aqueous solution and the main fuel 1 are injected into the combustion chamber using, for example, an integrated nozzle shown in FIG. 2 and burned from a port provided at another position. Supply air 8.

  For example, when applied to a diesel engine, an opening / closing port as an injection means 6 is provided in the vicinity of a fuel nozzle for injecting the main fuel 1, and the opening / closing port is opened at the timing when the main fuel 1 self-ignites to prepare a prepared alcohol aqueous solution. Supply.

  The supply amount of the alcohol fuel 4 into the combustion chamber 2 is determined according to the amount of heat generated by the alcohol fuel 4 to be obtained. The amount of water 3 supplied into the combustion chamber 2 is determined according to how many times the temperature of the combustion gas is lowered. Then, the flow rate and the alcohol concentration of the prepared alcohol aqueous solution are determined so that the supply amount of the alcohol-based fuel 4 and the supply amount of the water 3 become target values.

  Next, a second embodiment of the combustor of the present invention will be described based on FIG. In addition, the same code | symbol is attached | subjected about the apparatus same as the apparatus shown in FIG. 1, and description about them is abbreviate | omitted (same also about FIGS. 4-7).

  In the combustion apparatus of FIG. 1, the prepared alcohol aqueous solution is injected alone into the combustion chamber 2, but in this embodiment, the prepared alcohol aqueous solution is injected into the combustion chamber 2 together with the main fuel 1. That is, in this embodiment, the fuel nozzle that injects the main fuel 1 and the prepared alcohol aqueous solution together is the injection means 6.

  In addition, when the prepared alcohol aqueous solution is injected together with the main fuel 1, when the main fuel 1 is liquid, the liquid alcohol fuel 4 (prepared alcohol aqueous solution) is injected together, and when the main fuel 1 is gas, gas is used. It is preferable to inject the alcohol fuel 4 (vapor of the prepared alcohol aqueous solution) together. By combining these, the main fuel 1 and the alcohol-based fuel 4 can be mixed better, and the entire high-temperature region of the combustion gas of the main fuel 1 can be cooled more uniformly. However, the vapor of the prepared alcohol aqueous solution can be injected together when the main fuel 1 is liquid, and the prepared alcohol aqueous solution can also be injected together when the main fuel 1 is gas. Even in these combinations, the main fuel 1 and the alcohol-based fuel 4 can be smoothly supplied to the combustion gas of the main fuel 1. When the main fuel 1 is solid, the alcohol fuel 4 may be either liquid or gas. In any combination, the main fuel 1 and the alcohol fuel 4 can be smoothly supplied to the combustion gas of the main fuel 1.

  The prepared alcohol aqueous solution mixed and prepared by the mixing means 5 is supplied to the fuel mixing means 18 provided in the middle of the supply line 19 of the main fuel 1 and mixed with the main fuel 1. The prepared alcohol aqueous solution flows together with the main fuel 1 even if it is mixed with the main fuel 1 or is not mixed, and is injected into the combustion chamber 2 from the fuel nozzle as the injection means 6 and burned. Here, the fuel mixing means 18 is, for example, a collecting pipe that joins the flow path 20 of the prepared alcohol aqueous solution to the supply line 19 of the main fuel 1. However, the present invention is not limited to the collecting pipe, and any pipe that can join the flow of the prepared alcohol aqueous solution to the flow of the main fuel 1 can be used.

  Also in this embodiment, the prepared alcohol aqueous solution can be supplied to the combustion gas of the main fuel 1, the alcohol fuel 4 can be used, the generation of thermal NOx can be suppressed, and the combustion air 8 The effect of not reducing the supply amount is the same.

  Moreover, since the prepared alcohol aqueous solution is injected together with the main fuel 1, almost all of the injected water 3 can be reliably delivered to the combustion gas, and the generation of thermal NOx can be suppressed more efficiently. it can.

  In the present invention, since the prepared alcohol aqueous solution is injected together with the main fuel 1, it is not necessary to provide an injection nozzle dedicated to the prepared alcohol aqueous solution, and the equipment can be simplified.

  In addition, since it is not necessary to dissolve or sufficiently mix the alcohol fuel 4 in the main fuel 1, even if the main fuel 1 is difficult to dissolve or difficult to mix the alcohol fuel 4, the alcohol fuel 4 Can be supplied into the combustion chamber 2 and burned well.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention.

  For example, in the above description, the water / alcohol supply system 9 supplies the prepared alcohol aqueous solution prepared by mixing by the mixing means 5 to the injection means 6 in a liquid state, but is not necessarily limited to this configuration. For example, as shown in FIG. 4, a prepared alcohol aqueous solution prepared by mixing by the mixing means 5 may be evaporated by the steam generator 21 and supplied to the injection means 6 as vapor (gas). Alternatively, for example, as shown in FIG. 5, the prepared alcohol aqueous solution prepared by mixing by the mixing unit 5 may be evaporated by the steam generator 21 and mixed with the main fuel 1 by the fuel mixing unit 18. Also in these cases, the alcohol fuel 4 can be supplied into the combustion chamber 2, and the temperature of the combustion gas of the main fuel 1 can be lowered to suppress the generation of thermal NOx. 4 is particularly suitable when a liquid fuel is used as the main fuel 1, and the combustion apparatus of FIG. 5 is particularly suitable when a gas fuel is used as the main fuel 1. As the steam generator 21, for example, a boiler can be used.

  In the above description, the mixing means 5 is simply a collecting pipe that joins the flow of the aqueous alcohol solution 7 to the flow of the water 3, but is not limited to this. For example, the mixing means 5 is heated while joining the flows of the two. It is good also as a steam generator to evaporate. That is, the combustion device of FIG. 4 and the mixing means 5 and the steam generator 21 in the combustion device of FIG. 5 may be integrated. Also in these cases, the alcohol fuel 4 can be supplied into the combustion chamber 2, and the temperature of the combustion gas of the main fuel 1 can be lowered to suppress the generation of thermal NOx.

  For example, as shown in FIG. 6, after the water 3 and the aqueous alcohol solution 7 are supplied to the steam generator 21 and evaporated, the water vapor and the alcohol fuel vapor are supplied to the mixing means 5 and mixed to be injected. Alternatively, for example, as shown in FIG. 7, the mixed vapor mixed by the mixing unit 5 may be mixed with the main fuel 1 by the fuel mixing unit 18. Also in these cases, the alcohol fuel 4 can be supplied into the combustion chamber 2, and the temperature of the combustion gas of the main fuel 1 can be lowered to suppress the generation of thermal NOx. The steam generator 21 for evaporating the water 3 and the steam generator 21 for evaporating the aqueous alcohol solution 7 may be provided separately, or a common steam generator 21 is used as shown in FIG. 6 or FIG. May be.

  A trial calculation was performed to confirm the influence on the thermal NOx suppression effect by mixing alcohol fuel with water for thermal NOx suppression. The calculation was performed for the case where the alcohol-based fuel addition rate to the water for suppressing thermal NOx was 0 wt%, 5 wt%, 10 wt%, 20 wt%, and 30 wt%. This is a trial calculation using a gas turbine with a combustor pressure of 2.0 MPa and an air temperature of 400 ° C., assuming ethanol as the alcohol fuel and light oil as the main fuel. This is a trial calculation based on the reduction of the flame temperature and may be different from the actual operation.

  The result is shown in FIG. The horizontal axis represents the ratio (kg / kg) of the alcohol aqueous solution (water mixed with alcohol fuel) to the main fuel, and the vertical axis represents the NOx reduction rate. Here, the NOx reduction rate is expressed as NOx concentration of exhaust gas when water for suppressing thermal NOx is supplied to the combustion gas of the main fuel, N0 is NOx concentration of exhaust gas when water for suppressing thermal NOx is not supplied. In this case, it is expressed as N / N0.

  As can be seen from FIG. 8, the NOx reduction rate decreases as the addition rate of alcohol fuel (ethanol) decreases. However, even when the alcohol fuel addition rate is the largest, 30% by weight, the NOx reduction rate is reduced to 1/0 when the ratio is 0 by increasing the ratio of water (including ethanol) to the main fuel to 2.4. It was found that it can be reduced to 6 or less.

  Next, FIG. 8 is simply shown as the ratio of water and main fuel (FIG. 9). The horizontal axis is the ratio of water to main fuel (kg / kg), and the vertical axis is the NOx reduction rate. As is clear from FIG. 9, the relationship between the water / main fuel ratio and the NOx reduction rate hardly changed even when the alcohol fuel addition rate was changed. This is presumably because the flame temperature of ethanol is low, so that the combustion gas temperature hardly changes even if the addition rate of ethanol is increased. That is, it was confirmed that the water / main fuel ratio mainly dominates the NOx reduction rate, and even if alcohol-based fuel is mixed with water for suppressing thermal NOx, the amount of thermal NOx generated is not significantly affected. That is, even if alcohol fuel is mixed with water or water vapor for suppressing thermal NOx and injected into the combustion chamber as in the present invention, the amount of thermal NOx generated is not affected so much, and alcohol fuel can be used. It was confirmed that only the advantage of this would stand out. The supply amount of the main fuel can be reduced by an amount corresponding to the calorific value of the alcohol fuel.

DESCRIPTION OF SYMBOLS 1 Main fuel 2 Combustion chamber 3 Water or water vapor | steam for thermal NOx suppression 4 Alcohol-type fuel 5 Mixing means 6 Injection means

Claims (6)

  In a fuel supply method for a combustion apparatus for supplying water or steam for suppressing thermal NOx to combustion gas of main fuel, an alcohol-based fuel is mixed with water or steam for suppressing thermal NOx and together with or alone with the main fuel A fuel supply method for combustion equipment, wherein the fuel is injected into the combustion chamber.   2. The fuel supply method for a combustion apparatus according to claim 1, wherein the alcohol concentration in water or water vapor mixed with the alcohol fuel is less than 60% by weight.   The fuel supply method for a combustion device according to claim 2, wherein an alcohol aqueous solution having an alcohol concentration of less than 60% by weight is mixed with the water or water vapor.   2. The fuel supply method for a combustion apparatus according to claim 1, wherein the alcohol fuel is derived from a plant.   The fuel supply method for a combustion apparatus according to claim 1, wherein the alcohol fuel is bioethanol.   Combustion chamber for burning main fuel, mixing means for mixing alcohol fuel with water or water vapor for suppressing thermal NOx, water or water vapor mixed with the alcohol fuel together with the main fuel or alone Combustion equipment comprising injection means for injecting into a combustion chamber.

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