JP2000063857A - Method and apparatus for high-efficiency combustion of water/fossil fuel mixed emulsion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for combusting a water/fossil mixed emulsion at high efficiency and a high calorific value without forming much CO2, which method comprises introducing and jetting combustion air preheated to a specified or higher temperature into a combustion chamber, jetting the fuel into the combustion chamber by the help of the air stream and effecting the low oxygen concentration combustion of the fuel. SOLUTION: Combustion air is press injected from an air intake port 7 into an air heater 5 operated by electromagnetic induction heating or microwave heating at a speed of 80-100 m/sec by means of a blower 6 and heated to 1,000 deg.C or higher. The high-temperature heated air is branched at a high-temperature air header 8 and injected at a high speed from an air nozzle 10 as the combustion air of a burner 3, and it may be blown into the heater after it is branched into primary air and secondary air for promoting combustion. On the other hand, the water/fossil fuel mixed emulsion in a storage tank 1 is sprayed into the high-speed combustion air stream from the fuel nozzle 15 of the burner 3 by a fuel pump 2 and is ignited with the burner 3. The above combustion is possible in such a low oxygen concentration that the combustion air is used in a quantity of 34-23% of the theoretical air quantity necessary for combusting the fossil fuel in the emulsion.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a combustion method and a combustion apparatus using emulsion fuel. More specifically, the present invention relates to a low oxygen concentration, high efficiency combustion method and a combustion apparatus using a water-fossil fuel mixed emulsion as a fuel.

[0002]

2. Description of the Related Art Conventionally, various proposals have been made to mix fossil liquid fuel with water and burn it as a fuel emulsion from the viewpoint of energy saving and reduction of soot and nitrogen oxides. Further, in recent years, reduction of CO ₂ (carbon dioxide) emission has been demanded on a global scale, and a fuel combustion system capable of obtaining a constant combustion calorie with a CO ₂ emission as small as possible has been demanded. Since the water-fossil fuel mixed emulsion can reduce CO ₂ emission at the time of combustion as compared with fossil fuel by mixing water, water-fossil fuel mixed emulsion can be used together with the above-mentioned request for energy saving.
It has been desired to develop a method and an apparatus for efficiently and economically burning a fossil fuel mixed emulsion. On the other hand, high-performance industrial furnaces that burn fossil liquid fuel with high efficiency have already been put to practical use. In order to realize this highly efficient combustion, it is necessary to preheat the intake air to 1000 ° C or higher. Conventionally, as a preheating device, a device that obtains preheated air of 1000 ° C. or more by exchanging (burning alternately) two burners having a heat storage body, for example, NFK-HRS radiant tube burner manufactured by Japan Furnace Industry Co., Ltd. System (brand name), North American FDI twin bed burner (brand name), etc. are available. The preheating by this exchange combustion is
This is a method in which the exhaust gas from the combustion of one burner is discharged from the other non-activated burner side, and the heat is absorbed by the heat storage body at the discharge portion, and this is performed alternately.
However, since these devices require two burner installation parts, it is difficult to adopt them in a boiler or a gas turbine of a normal structure, and the operating time of one of the burners, which can usually be used only in a furnace, 100 burning air inside
It has a drawback that a large amount of heat storage body is required for heat exchange and preheating at 0 ° C or higher. In addition, this is not one in which high-efficiency combustion was performed with a water-fossil fuel mixed emulsion, and as described above, a water-fossil fuel mixed emulsion having many advantages over the combustion of only fossil fuel can be used. It has been desired to develop an efficient combustion method and a combustion device.

[0003]

Therefore, the present invention is
An object of the present invention is to provide a highly efficient combustion method and a combustion apparatus using a water-fossil fuel mixed emulsion, which can burn a water-fossil fuel mixed emulsion with energy efficiency and obtain a high calorific value with a small amount of generated CO ₂ .

[0004]

Means for Solving the Problems The inventors of the present invention have made extensive studies in view of the above problems, and as a result, introduced combustion air preheated to 1000 ° C. or higher into a combustion chamber for high-speed injection, and the air-flow produced water-fossil fuel. By injecting the mixed emulsion into the combustion chamber, it was found that the emulsion fuel can be uniformly dispersed in the combustion chamber as colloidal fine particles to realize low oxygen and high efficiency combustion, and the present invention has been completed based on this finding. That is, the present invention is characterized in that (1) combustion air preheated to 1000 ° C. or higher is introduced into a combustion chamber for high-speed injection, and a water-fossil fuel mixed emulsion is injected into the combustion chamber for low oxygen combustion. Burning method,
(2) Combustion air is blown at a velocity of 80 to 100 m / sec. (1) The combustion method according to the item (3), (3) Electromagnetic induction fluid heating device or micro in which preheating of the combustion air is provided in the preceding stage of the combustion chamber. (1) or (2), the air nozzle for injecting combustion air into the combustion chamber at high speed, and water-fossil in the air flow. A combustion device characterized by being provided with a fuel nozzle capable of introducing a fuel mixed emulsion, and an air heating device being provided in a combustion air introduction pipe of the combustion chamber. (5) The combustion device is a boiler. The combustion device according to (4), the air heating device according to (6) is an electromagnetic induction fluid heating device, and the combustion device according to (4) or (5), and the air heating device according to (7) are microwave fluids. A heating device (4) or (5 There is provided a combustion apparatus of claim wherein.

[0005]

DETAILED DESCRIPTION OF THE INVENTION The water-fossil fuel mixed emulsion to be burned in the present invention is a liquid fuel comprising water and a fossil fuel liquid. Examples of this emulsion include a water-in-oil emulsion and an oil-in-water emulsion, but the type of emulsion is not particularly limited. Examples of fossil fuel liquids include kerosene, light oil, and heavy oil. The water is not particularly limited, such as tap water and distilled water. The mixing ratio of water and fossil fuel liquid in the water-fossil fuel mixed emulsion that can be used in the present invention is not particularly limited, but the ratio of fossil fuel liquid in the emulsion is usually 85 to 40% by volume. From the viewpoint of reducing CO ₂ emission during combustion, 70 to 40% is preferable and 50
-40% is more preferable. Further, it is possible to use a water-fossil fuel mixed emulsion (Japanese Patent Application No. 9-308958) in which the proportion of water is increased by using hydroxyl ion water (pH 8.5 to 10) previously proposed by the present inventors. it can.

In addition to water and fossil fuel, a surfactant and tourmaline may be added to the water-fossil fuel mixed emulsion, if necessary. For example, obtained by adding distilled water to a synthetic anionic surfactant solution agent in which sodium alkyl ether sulfate of anionic surfactant and sodium alkylbenzene sulfonate, which have been previously proposed by the present inventors, are mixed and homogenized. A water-fossil fuel mixed emulsion fuel prepared by mixing and stirring a concentrated emulsion fuel material prepared by mixing and stirring a petroleum-based liquid fuel material into a mousse-like emulsifier uniformly containing bubbles
No. -1112267) and the like can be preferably used.

In the present invention, the water-fossil fuel mixed emulsion does not need to be particularly heated and is sprayed from the burner nozzle into the high-speed air stream of combustion air at room temperature. This allows the emulsion fuel to be effectively diffused into the combustion chamber. The pressure at the time of spraying is not particularly limited, but is usually 0.1 to 2 MPa, preferably 0.7 to
It is 1.5 MPa. The spray amount is determined in consideration of the capacity of the boiler or burner used.

The air stream of the combustion air thus sprayed with the water-fossil fuel mixed emulsion is ignited and burned by the spark plug attached to the burner. The combustion air used in the present invention, after being taken in from the air intake, is usually heated to 1000 ° C. or higher, preferably 10 ° C., by an air heating device.
50 to 1200 ° C., more preferably 1100 to 1200
It is heated to ℃ and injected at high speed near the fuel spray section of the burner. Combustion air may be branched and blown as primary air for high speed air flow and secondary air for combustion promotion. Blowing speed is usually 80 to 100 m / se
c, preferably 90 to 100 m / sec, more preferably 95 to 100 m / sec. The range is the same when branched to form primary and secondary air. Further, in the present invention, it is possible to perform combustion with a low oxygen concentration. Low-oxygen combustion means only fossil fuel, for example 4.8%
Combustion of oxygen concentration. Normally, 21% oxygen is contained in the atmosphere, so that 4.8% combustion can be performed by setting the intake air amount to 23% of the theoretical air amount. Since the emulsion fuel is used in the present invention, the combustion air is, for example, 34 to 23%, preferably 32 to 23% of the theoretical air amount of the fossil fuel component in the emulsion to be used.
%, More preferably 30 to 23%, combustion with a low oxygen concentration can be performed, and the emission of nitrogen oxides due to combustion can be further suppressed.

The air heating device used in the present invention is not particularly limited as long as it can be heated to 1000 ° C. or higher and is advantageous from the viewpoint of energy saving.
Examples include an electromagnetic induction fluid heating device and a microwave fluid heating device.

The electromagnetic induction fluid heating device comprises, for example, a combination of a metal heating element for performing the first stage heating and a carbon ceramic heating element for performing the second stage heating, and these heating elements are generated by a high frequency electromagnetic induction work coil. An example is a device that generates heat by the generated eddy current. In this case, the high frequency power supplied to the work coil is preferably produced by a high frequency inverter unit with an active filter, and one capable of increasing the commercial frequency to 50 to 100 kHz is preferable.

As the microwave fluid heating device, for example,
A mixture of carbon powder and alumina powder is sealed in a vacuum inside a quartz tube, quartz wool is packed at both ends of the quartz tube to seal the mixture, and both ends of the quartz tube are heat-sealed. A high-temperature heating element described in Japanese Patent No. 2525506, in which carbon powder is mainly dielectrically heated to a high temperature by irradiating a thing with a microwave of 2450 MHz which is a microwave used in a microwave oven or the like, ,
Similarly, the high-temperature heating element described in Japanese Patent No. 2017765, which is formed by compression-molding carbon powder into a cylindrical shape and which generates heat by microwave irradiation, can be used.

When an electromagnetic induction fluid heating apparatus or a microwave fluid heating apparatus is used as the air heating apparatus, since the heating energy source is electric power, it is required to suppress the electric power consumption in order to save energy. In the present invention, since the air introduced in the previous stage of the combustion chamber is heated, the heating target is only the intake air, and the heating efficiency is high because the specific heat of the air itself is small. Furthermore, since the amount of intake air can be reduced, the amount of heating air is smaller than that in normal combustion. Therefore, it is advantageous from the viewpoint of energy saving. In addition, these air heating devices may be provided in front of a combustion chamber of a combustion device such as a boiler, and have a structure of the combustion device (for example, vertical type (combustion air is ejected in the vertical direction)) or horizontal type (combustion air is It can be provided without being limited to (the one ejected in the horizontal direction)).

Due to the structure of the device of the present invention, the high temperature air of 1000 ° C. or higher heated by the air heating device comes into contact with the surface of the burner. Therefore, it is necessary to take a heat resistance measure for the burner. The surface of the structural material of the burner may be treated with a ceramic coating paint that can withstand temperatures of 1400 ° C or higher.

When a water pipe for absorbing radiant energy is provided in the combustion device used in the present invention, the water supplied to the water pipe is not particularly limited and may be tap water or ground water. Adhesion of scale to the inner wall of the water pipe can be suppressed.

In the present invention, it is considered that when the water-fossil fuel mixed emulsion is used as a fuel, a part of the water in the fuel undergoes a chemical reaction during combustion to release energy. Therefore, a small amount of fuel is required to obtain the same amount of heat as in the case of using only fossil liquid fuel. Further, as described above, since it is possible to reduce the amount of intake air compared to the case where combustion is performed only with fossil liquid fuel, the energy required for heating the combustion air can be saved, and not only soot dust but also nitrogen oxides due to high temperature combustion Can be suppressed. In the present invention, the water contained in the water-fossil fuel emulsion is steamed at an extremely high temperature, so that the combustion temperature of the flame rises by about 700 ° C. as compared with the case where only fossil fuel is used, so that the radiant energy increases. Further, in the present invention, the volume of flame is expanded from several times to several tens of times, and the energy radiating area is increased. Generally, the emission rate of radiant energy is CO ₂
It is known that water vapor is larger and N ₂ is not substantially released. However, since the present invention uses the water-fossil fuel mixed emulsion, the proportion of water vapor in the combustion gas is high and the proportion of CO ₂ is Is low and the emission of radiant energy is high. Further, when the amount of intake air is reduced, the proportion of N ₂ is also low, so that the emission of radiant energy is further increased. In consideration of the above points, according to the present invention, soot and nitrogen oxides can be suppressed, and the amount of radiant energy of the flame can be increased as compared with conventional combustion.

That is, since the combustion method and the combustion apparatus of the present invention can obtain high combustion calories by using the water-fossil fuel mixed emulsion as a fuel, it is economical compared with the case where the combustion is performed only with the fossil liquid fuel. It is efficient and energy-saving, and the emission gas that causes pollution can be reduced significantly.

Next, the combustion method and combustion apparatus of the present invention will be described in more detail with reference to the drawings. The same reference numerals in the drawings indicate the same things. 1 and 2 are explanatory diagrams showing the configuration of an embodiment of the apparatus of the present invention. In the embodiment of FIG. 1, the combustion air is blown by the blower 6 into the air intake 7.
Is press-fitted into the air heating device 5 and heated to 1000 ° C. or higher. This high-temperature heated air is branched by the high-temperature air header 8 and is jetted at high speed from the air nozzle 10 as combustion air for the burner 3 provided above the combustion device 9. FIG. 2 shows another embodiment in which a water pipe is provided in the combustion chamber and is branched as primary and secondary air. The primary air is ejected from the air nozzle 30 and the secondary air is ejected from the air nozzle 31. Further, in these embodiments, the inner diameter of the pipe may be reduced between the air heating device 5 or 29 and the air nozzle 10 or 30 and 31 for the purpose of increasing the ejection speed. In FIG. 2, a DPH (trade name) gas heating section, which is an example of an electromagnetic induction fluid heating apparatus, is used as the air heating apparatus. However, for example, the microwave fluid heating apparatus described in the above-mentioned Japanese Patent No. 2525506 may also be used. It can be used and is not particularly limited. Note that the combustion air can be supplied to the combustion chamber 4 with a damper (not shown) attached to the blower 6 of the air intake port 7, the amount of which is less than the theoretical air amount. On the other hand, the water-fossil fuel mixed emulsion is sprayed from the storage tank 1 by the fuel pump 2 from the fuel nozzle 15 of the burner 3 into the high speed air flow of the combustion air. The sprayed water-fossil fuel mixed emulsion is ignited by a spark plug (not shown) attached to the burner 3,
To burn. The heat quantity of the exhaust gas emitted from the exhaust port 25 can be recovered by a heat recovery device that is generally used, and the boiler efficiency can be improved.

FIG. 3 shows a flame 11 and a water pipe 12 when the radiant energy is absorbed by the water pipe in the combustion apparatus 9 of the present invention.
Although a schematic layout drawing of and is shown in cross section, it does not limit the direction of the water pipe with respect to the flame or the number of water pipes, and for example, the water pipes may be arranged in double. The energy emitted from the flame 11 is absorbed by the water pipe 12,
It is taken out as steam 17 and used. The aspect of the apparatus of the present invention in this case is as shown in FIG. These water pipes have an upper header 2 at their upper and lower parts, respectively.
3, connected by the lower header 24. Here, the water treated by the water treatment device 13 is sent to the water pipe 12 by the press-fitting water supply pump 14, and the generated steam mixture is separated by the steam separator 16.
Separated in and taken out as steam 17. The separated water can be reused for water pipe supply.

FIG. 4 is an explanatory view showing an example of the electromagnetic induction fluid heating device. In FIG. 4, the intake air is the temperature sensor 1
Under the control of 9, the metal heating element 18 receives the first-stage heating, and then the carbon ceramic heating element 20 heats it to the target temperature under the control of the temperature sensor 21. Both the heating elements 18 and 20 are supplied with electric power from the inverter unit 22 and generate heat by electromagnetic induction as described above. In addition, although heating is performed in two steps in this device,
In particular, the heating device used in the present invention is not limited to a device that performs heating in multiple stages.

INDUSTRIAL APPLICABILITY The combustion method and combustion apparatus of the present invention can be used in various systems that operate by hot air or steam. For example, a hot air generator, a gas turbine generator, etc. are connected to the above boiler. Can be used.

[0021]

The present invention will be described in more detail based on the following examples, but the invention is not intended to be limited thereto. Example 1 A boiler system having the configuration shown in FIG. 2 was constructed and operated,
The amount of heat generated and the like were measured. Reference numeral 28 denotes a main body based on a steam boiler (Ehara Steam Boiler ST200, manufactured by EBARA CORPORATION). This boiler system is a steam boiler 28
An example in which a water-fossil fuel mixed emulsion high efficiency radiant energy absorption type steam boiler is modified by providing a water-fossil fuel mixed emulsion supply section and a DPH (trade name) high temperature gas heating section 29 as an electromagnetic induction fluid heating device Is. As the water-fossil fuel mixed emulsion, treated water obtained by treating tap water and heavy oil A were used at a volume ratio of 50:50, and as the surfactant, α-olefin sulfonate (AOS) and an alkyl sulfate polypolyether of the same volume. Oxyethylene ether salt (AES) was used, and these were made into water-in-oil emulsions according to the above-mentioned JP-A No. 9-111267.

The water-A heavy oil mixed emulsion is burned at room temperature by spraying it from a burner nozzle (not shown) at 0.7 MPa and 14.1 liters / hour for 10 hours in a high-speed air stream of combustion air at room temperature. It was blown into the chamber 4. Combustion air is heated to 1100 ° C. by the DPH high temperature gas heating unit 29, and the primary and secondary burner 3
Next air as air nozzles 30, 31 to 100 respectively
It was supplied at a speed of m / sec for 10 hours. The heating efficiency η _heat of the DPH high temperature gas heating unit including the inverter unit was 85%. The intake air amount is a damper (not shown)
The theoretical air amount of heavy oil A contained in the emulsion is 23
%, And the combustion was low oxygen combustion. Spark plug (not shown) for high-speed air flow sprayed with emulsion fuel
When ignited at, the high temperature of primary and secondary air, the maximum temperature 2000 times more than 5 times the volume of the conventional
It burned as a flame 11 of ℃. The radiant energy from the flame 11 was absorbed by the water pipe 12 and taken out as steam 17 by the steam separator 16. To this water pipe 12, water that was generally treated by the water treatment device 13 was supplied by a pump 14.

The calorific value of this boiler system using a water-A heavy oil mixed emulsion as a fuel was measured by a steam heat measuring system which automatically measures the calorific value from the calorific value of the inlet water and the calorific value of the outlet steam.
It was kg. In addition, when the amount of soot and nitrogen oxides in the combustion exhaust was measured, no soot was generated, and nitrogen oxides should be kept to 7ppm or less, which is 1/8 or less of high temperature air combustion using conventional fossil fuels. I was able to.

Heavy oil A (Lower calorific value of about 10200 kcal
/ Kg), the fuel cost is calculated by adding the cost of each raw material to the ratio of the cost of water-A heavy oil mixed emulsion (calorific value about 11220 kcal / kg) generated in the above boiler system to A heavy oil. It can be reduced by about 50%. By using emulsion fuel, the amount of CO ₂ generated can be reduced by about 55% with respect to A heavy oil, assuming the same amount of heat generation. Also, 1
The heat output of steam generated per hour was 125 kW, whereas the external input required 6 kW as air preheating power, and the heat output was about 21 times that of this input. As a comparison, when a water-A heavy oil mixed emulsion having a volume ratio of water: A heavy oil of 50:50 is burned in a normal boiler, the emulsion fuel itself reduces the amount of nitrogen oxides and CO ₂ in the exhaust gas to some extent and reduces the cost. Although there was a down, the increase in calorific value that is thought to be due to the chemical reaction of water as described above,
It was not possible to achieve significant reductions in soot and nitrogen oxides that would be more effective by performing low-oxygen combustion.

Comparative Example 1 The calorific value was measured in the same manner as in Example 1 except that the water-A heavy oil mixed emulsion of the fuel was changed to A heavy oil only, and the calorific value was measured and found to be 11000 kcal / kg. Further, the amounts of soot dust and nitrogen oxides in the combustion exhaust gas were similar to those in conventional high temperature air combustion, and no improvement was observed.

[0026]

According to the present invention, water-fossil fuel mixed emulsion is uniformly dispersed in a high temperature combustion chamber as colloidal fine particles and burned with high energy efficiency to cause pollution such as CO ₂ and nitrogen oxides. , Suppress the generation of soot and dust,
A high calorific value can be obtained. Further, according to the present invention, the preheating of the combustion air is performed by the air heating device provided in the preceding stage of the combustion chamber, and therefore, there is an excellent effect that the structure of the combustion device is not limited.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a combustion device of the present invention.

FIG. 2 is an explanatory diagram showing a configuration of a combustion device having a water pipe and primary and secondary air nozzles and an air heating device being an electromagnetic induction fluid heating device of the present invention.

FIG. 3 is a schematic diagram showing an arrangement of a flame and a water pipe of the combustion apparatus of the present invention.

FIG. 4 is an explanatory diagram showing an example of an electromagnetic induction fluid heating device.

[Explanation of symbols]

1 Water-fossil fuel mixed emulsion storage tank 2 fuel pump 3 Burner with spark plug 4 Combustion chamber 5 Air heating device 6 Blower 7 Air intake 8 hot air header 9 Combustion device 10, 30, 31 Air nozzle 11 flames 12 water tubes 13 Water treatment device 14 Press fit water supply pump 15 burner fuel nozzle 16 steam separator 17 steam 18 Metal heating element 19, 21 Temperature sensor 20 Carbon ceramic heating element 22 Inverter unit 23 Upper header 24 Lower header 25 exhaust port 28 steam boilers 29 DPH High temperature gas heating unit

Continued front page    (72) Inventor Yutaka Hashimoto             4-28 Akai, Kawaguchi City, Saitama Prefecture Daimo             Within the corporation F term (reference) 3K052 GA05 GA06 GB01 GB04 GC01                       GD03 GD08 GE01 GE07 HA01                 4H013 DC07

Claims (7)

[Claims] 1. Combustion characterized by introducing combustion air preheated to 1000 ° C. or higher into a combustion chamber for high-speed injection and injecting a water-fossil fuel mixed emulsion into the combustion chamber for low oxygen combustion. Method. 2. The velocity of combustion air is 80 to 100 m / sec.
The combustion method according to claim 1, wherein the combustion method is performed by blowing. 3. The combustion method according to claim 1, wherein the combustion air is preheated by an electromagnetic induction fluid heating device or a microwave fluid heating device provided in the preceding stage of the combustion chamber. 4. The combustion chamber is provided with an air nozzle for injecting combustion air at a high speed and a fuel nozzle adapted to introduce a water-fossil fuel mixed emulsion into the air flow. Combustion device, characterized in that an air heating device is provided in the introduction pipe of. 5. The combustion device according to claim 4, wherein the combustion device is a boiler. 6. The combustion device according to claim 4, wherein the air heating device is an electromagnetic induction fluid heating device. 7. The combustion device according to claim 4, wherein the air heating device is a microwave fluid heating device.