WO2023090027A1

WO2023090027A1 - Combustion efficiency improvement device

Info

Publication number: WO2023090027A1
Application number: PCT/JP2022/038696
Authority: WO
Inventors: 満末松; 則昭中桐
Original assignee: 株式会社アプライド・エナジー・ラボラトリー
Priority date: 2021-11-16
Filing date: 2022-10-18
Publication date: 2023-05-25
Also published as: JP2023073538A; JP7042540B1

Abstract

Provided is a combustion efficiency improvement device with which it is possible to improve combustion efficiency of a combustion device that burns liquid fuel. The combustion efficiency improvement device (1) according to the present invention is for improving combustion efficiency when liquid fuel (F) is burned in an external combustion device (200), and comprises: branch channels (20) which are incorporated such that the upstream sides thereof are separated from and the downstream sides thereof are merged with a main channel (10) for delivering the fuel (F) from an external fuel supply source (100) to the combustion device (200); nozzles (30) that are for generating bubbles (B) and are incorporated in the branching channels (20); and a pressure pump (22) for applying a prescribed pressure on the fuel (F) to be delivered toward the nozzles (30). The nozzles (30) each include a cavitation generation unit (31) which does not have a port for taking in gas from outside but is configured to cause a cavitation phenomenon while the fuel (F) under the prescribed pressure is being delivered, to thereby generate bubbles (B) in the fuel (F).

Description

Combustion efficiency improvement device

The present invention relates to a combustion efficiency improving device for improving combustion efficiency when burning liquid fuel in a combustion device.

Engines, boilers, burners, etc. are widely used as combustion devices that generate power and heat by burning liquid fuels such as light oil, heavy oil, and kerosene.

Regarding the above combustion equipment, research and development have been conducted to improve combustion efficiency by various methods. As one of them, a technique is disclosed in which gas is introduced from the outside to generate fine bubbles (microbubbles) with a diameter of less than 100 μm, which are mixed with fuel and supplied to a combustion device to improve combustion efficiency. (Patent Document 1: Japanese Unexamined Patent Application Publication No. 2007-24012).

Japanese Patent Application Laid-Open No. 2007-24012

As exemplified in the above literature, in the device that improves the combustion efficiency by mixing microbubbles into the liquid fuel, for example, in the case of a configuration that is incorporated in series in the fuel flow path, the failure of the improvement device main body Problems can sometimes arise that can bring the combustion system out of operation. In addition, in the case of a configuration in which air is taken in from the outside and mixed into the fuel, there is a problem that due to poor control or insufficient adjustment, air can accumulate in the flow path (piping), resulting in damage to the combustion device and poor combustion. can occur.

The present invention has been made in view of the above circumstances, and when burning liquid fuel in a combustion device, it is possible to prevent damage to the combustion device and poor combustion. An object of the present invention is to provide a combustion efficiency improving device capable of improving combustion efficiency without stopping the operation of the device.

As one embodiment, the above problems are solved by the following solution means.

A combustion efficiency improvement device according to one embodiment is a combustion efficiency improvement device for improving combustion efficiency when liquid fuel is burned in an external combustion device, wherein the fuel is supplied from an external fuel supply source to the combustion device. a branched flow path that branches upstream from the main flow path that feeds the fuel and that is incorporated to merge on the downstream side; a nozzle that is incorporated in the branched flow path to generate bubbles; a pressurizing pump that applies pressure and sends the fuel toward the nozzle, the nozzle having no gas suction port from the outside and cavitation when the fuel of the predetermined pressure flows. a cavitation generating portion that generates the bubbles in the fuel by causing a phenomenon, wherein the branch flow path forms a loop-shaped flow path with respect to the main flow path, The predetermined pressure of the pressurizing pump is set so as not to change the pressure on the upstream side and the pressure on the downstream side from the confluence position, and the branch position is relative to the position of the fuel pump provided in the fuel supply source. provided at a downstream position in the main flow path.

According to the disclosed combustion efficiency improvement device, it is possible to improve combustion efficiency in a combustion device that generates power and heat by burning liquid fuel such as light oil, heavy oil, and kerosene. In addition, it is possible to prevent the operation of the combustion device from being stopped when the combustion efficiency improvement device itself fails, and prevent air pockets in the fuel flow path (pipe) due to poor control or insufficient adjustment of the combustion efficiency improvement device. It is also possible to prevent damage to the combustion device and poor combustion from occurring.

FIG. 1 is a configuration diagram showing an example of an entire combustion system in which a combustion efficiency improving device according to this embodiment is incorporated. FIG. 2 is a schematic diagram showing an example of a combustion efficiency improving device according to this embodiment. FIG. 3 is a schematic diagram showing an example of a nozzle of the combustion efficiency improving device according to this embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an example of an entire combustion system in which a combustion efficiency improving device 1 according to this embodiment is installed. FIG. 2 is a schematic diagram showing an example of the combustion efficiency improving device 1 according to this embodiment. In addition, in all drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and repeated description thereof may be omitted.

The combustion efficiency improving device 1 according to this embodiment is a device that improves the combustion efficiency when liquid fuel is burned in an external combustion device. Examples of the "liquid fuel" include light oil, heavy oil (preferably heavy oil A), and kerosene. Examples of "combustion device" include an engine, a boiler, a burner, and the like.

As shown in FIGS. 1 and 2, the combustion efficiency improving device 1 is first positioned upstream (second 1 position) 11 and joins at a downstream position (second position) 12 to form an annular flow path. Further, as a configuration incorporated in the branch flow path 20, a nozzle 30 for generating a bubble B and a pressure pump 22 for applying a predetermined pressure to the fuel F and feeding it toward the nozzle 30 are provided.

The external fuel supply source 100 includes, for example, a tank 101 that stores the liquid fuel F and a fuel pump (feed pump) 102 that feeds the fuel F from the tank 101 to the main flow path 10. . However, the present invention is not limited to this configuration, and a configuration in which the fuel F is fed by an injection pump (supply pump) provided in the combustion device 200 without the fuel pump (feed pump) may be employed (not shown). ).

Next, as shown in FIG. 3 (an enlarged cross-sectional view of part III in FIG. 2), the nozzle 30 according to the present embodiment does not have a gas suction port from the outside, and fuel F at a predetermined pressure flows through it. A cavitation generator 31 is provided for generating bubbles B, which will be described later, in the fuel F by actually causing a cavitation phenomenon.

That is, the nozzle 30 does not have a gas suction port seen in the technique of sucking gas from the outside to the inside to generate bubbles as exemplified in Patent Document 1, and the fuel F flowing through the inside does not have a gas suction port. By causing cavitation due to pressure change (decompression), the dissolved gas (in this case, air) and the liquid (constituent components) of fuel F (light oil, heavy oil, kerosene, etc.) itself evaporates to form bubble B. It is configured to generate

The nozzle 30 also includes a stirring portion 32 that generates a stirring flow in the fuel F when the fuel F at a predetermined pressure flows. In the present embodiment, the cavitation generating section 31 described above also serves as the stirring section 32 . However, it is not limited to this configuration, and may be provided separately (not shown).

Here, the branch channel 20 constitutes a loop-shaped channel with respect to the main channel 10 . Furthermore, the pressure of the pressure pump 22 is adjusted so as not to change the pressure upstream from the branch position (first position) 11 in the main flow path 10 and the pressure downstream from the junction position (second position) 12 in the main flow path 10. A predetermined pressure is set. With this configuration, for example, compared to conventional devices (not shown) that incorporate pressure pumps, nozzles, or tanks for providing them directly in the main flow path, the branch flow path 20 provides the main flow path 10 Since there is no (substantially no) pressure fluctuation, there is no effect on the delivery action and control of the fuel pump 102 and the fuel injection device 201 .

Specifically, the "predetermined pressure" applied to the fuel F when the pressurizing pump 22 described above feeds the fuel F toward the nozzle 30 is in the range of about 2 atmospheres to 10 atmospheres, and the combustion The pressure is set to be lower than the set injection pressure of the fuel injection device 201 provided in the device 200 . As an example of the "set injection pressure", if the fuel injection device 201 is an injection pump for a diesel engine, the set injection pressure is about 200 atmospheres, or if it is a common rail for a diesel engine, the set injection pressure is 2000 atmospheres. It is about atmospheric pressure.

As a power source for driving the pressurizing pump 22, for example, if the combustion device 200 is a diesel engine, an in-vehicle DC 24V battery or the like can be used, or if it is a boiler or the like, an external power source can be used. A 200 V three-phase AC power supply or the like can be used.

Further, the nozzle 30 is configured to generate ultra-fine bubbles having a particle size of less than 1 μm as the bubbles B when the fuel F pressure-fed by the pressure pump 22 passes through the nozzle 30 . However, "less than 1 μm in diameter" does not mean that bubbles with a diameter of 1 μm or more are completely excluded.

According to the above configuration, it is possible to generate ultra-fine bubbles in the fuel F that has passed through the nozzle 30 (they exist without disappearing for about a predetermined time, which will be described later), and to stir the fuel F. As a result, the fuel F (droplets) can be made finer (described later), and the finer droplets increase the specific surface area and shorten the combustion time. More specifically, assuming that the droplet of the fuel F is a sphere whose diameter is reduced by 20%, the total surface area of the same volume of fuel F is increased by 25%. At this time, the volume of one droplet is approximately 1/2. As a result, the fuel F is efficiently combined with oxygen, and the effect of approaching complete combustion is obtained. That is, the flame is less likely to spread, and the generated thermal energy is concentrated, so that the effect of improving the combustion efficiency can be obtained. For example, in the case of a diesel engine that burns fuel F in a cylinder, less heat is transferred to the cylinder, and more energy obtained by combustion can be used as power.

As a result of research conducted by the inventors of the present application, the above effects are considered as follows. First, regarding liquids such as light oil and heavy oil, it is generally known that the droplet size when injected by a fuel injection device has a linear relationship with the viscosity, and that the viscosity decreases as the temperature rises. In addition, thixotropy (physical property in which the viscosity decreases due to shear force such as stirring) is often observed in highly viscous liquids. Considering these phenomena in the case of this device, when the fuel F passes through the nozzle 30, the fuel F Ultra-fine bubbles are generated inside to stir the fuel F. At this time, it is considered that van der Waals bonds are partially released in the molecules constituting the fuel F, resulting in a decrease in viscosity and an effect of reducing the diameter of droplets.

Here, when a diesel engine is assumed as the combustion device 200, a pressure of about 200 atmospheres is applied to the fuel F at the injection pump serving as the fuel injection device 201, so the internal pressure is said to be about 30 atmospheres. The ultra-fine bubbles should disappear before injection. In that case, it is considered that the most important factor for improving the combustion efficiency is to give energy to the constituent particles (molecules) of the fuel F in the process of generating the bubbles B in the fuel F. Therefore, the combustion efficiency improvement effect of the present invention is even higher in a configuration including a conventional fuel injection device (injection pump) than in a configuration including a common rail fuel injection device.

On the other hand, if a boiler is assumed as the combustion device 200, the mechanism for improving combustion efficiency is slightly different from the above. Specifically, the combustion of the fuel F passed through the nozzle 30 approaches complete combustion and no soot is generated. This eliminates the large amount of soot adhering to the heat exchanger, which occurs in conventional combustion devices, and improves the heat exchange efficiency (that is, maintains the initial state of the device), improving combustion efficiency. effect can be obtained. Therefore, the combustion efficiency improvement effect of the present invention is even higher in the configuration with the spray burner than in the configuration with the gun type burner.

Through further experiments, the inventors of the present application found that the ultra-fine bubbles generated in the fuel F floated, polymerized and disappeared in a short period of time (about 30 seconds to 1 minute), and that the viscosity of the fuel F It was found that the decrease lasts only for a short period of time (about 30 seconds to 1 minute) and returns to the original state when left standing. Since these are problems in realizing the combustion efficiency improvement device, a configuration that enables the solution was devised.

Specifically, the nozzle 30 according to the present embodiment is located at a position where the flow time for the fuel F to reach the fuel injection device 201 of the combustion device 200 from the outflow port 34 of the nozzle 30 is a flow distance that does not exceed one minute. It was possible to solve the above problems by the configuration arranged in.

If the configuration is such that the fuel F stored in the tank 101 is subjected to the same processing as that in which the fuel F is passed through the nozzle 30 described above, then the fuel injection device 201 would be required to feed the fuel F over a long distance. The viscosity of the fuel F will return to the original viscosity by the time it reaches , and is consumed in combustion. On the other hand, according to the above configuration of the present embodiment, the fuel injection device can Since it reaches 201 and is consumed for combustion, the aforementioned effect of improving combustion efficiency can be obtained.

For example, in the case where the combustion device 200 is a diesel engine and a pipe having an inner diameter cross-sectional area of 1.7 square centimeters that is generally used as a fuel pipe serving as the main flow path 10 is used, up to the fuel injection device 201 A calculation of the distance X that the fuel F reaches in 30 seconds yields the following results. Specifically, for a fuel consumption of 6 liters/hour, X=approximately 30 centimeters. Also, when the fuel consumption is 24 liters/hour, X=approximately 117 centimeters. Also, when the fuel consumption is 60 liters/hour, X=approximately 294 centimeters. Thus, it is effective to set the installation position of the combustion efficiency improving device 1 (especially the nozzle 30) as close to the combustion device 200 (especially the fuel injection device 201) as possible. From another point of view, it can be said that the greater the fuel consumption of the combustion device 200, the higher the effect of improving the combustion efficiency according to the present invention.

As described above, according to the combustion efficiency improving device according to the present invention, it is possible to improve the fuel combustion efficiency in a configuration in which liquid fuel is burned in a combustion device.

In addition, in the case of a conventional device that sucks gas from the outside into the interior to generate bubbles, poor control or insufficient adjustment can cause air pockets in the flow path (piping), resulting in damage to the combustion device. However, according to the combustion efficiency improvement device according to the present invention, such a risk is eliminated (or reduced) by a configuration that does not have a gas suction port from the outside. becomes possible.

Furthermore, in the case of a structure that is incorporated in series with the fuel flow path like the conventional device, there is a risk that the operation of the combustion device will be stopped when the main body of the improvement device fails, but the combustion efficiency improvement according to the present invention According to the device, such a risk can be eliminated (or reduced) by a configuration comprising branch channels that are incorporated to form annular channels with respect to the main channel.

It should be noted that the present invention is not limited to the embodiments described above, and can be modified in various ways without departing from the scope of the present invention. As a modification of the present invention, when applied to a combustion device with a larger fuel consumption, two combustion efficiency improving devices according to the present invention may be connected in parallel to the main flow path through which fuel flows. becomes possible.

Claims

A combustion efficiency improving device for improving combustion efficiency when burning liquid fuel in an external combustion device,
a branched flow path that branches upstream from a main flow path that feeds the fuel from an external fuel supply source to the combustion device and joins the main flow path on the downstream side;
Both of them are incorporated in the branch flow path and comprise a nozzle that generates bubbles, and a pressure pump that applies a predetermined pressure to the fuel and sends it toward the nozzle,
The nozzle does not have a gas suction port from the outside, and has a cavitation generating part that generates the bubbles in the fuel by causing a cavitation phenomenon when the fuel at the predetermined pressure flows,
The branch flow path constitutes a loop-shaped flow path with respect to the main flow path, and the pressure is applied so as not to change the pressure upstream from the branch position and the pressure downstream from the confluence position in the main flow path. The predetermined pressure of the pump is set,
The combustion efficiency improving device, wherein the branch position is provided at a position downstream in the main flow path with respect to a position of a fuel pump provided in the fuel supply source.
2. The combustion efficiency improving device according to claim 1, wherein said branched flow path is configured as a loop-shaped flow path without branching on the way.
3. Combustion efficiency according to claim 1 or claim 2, wherein said predetermined pressure is between 2 atmospheres and 10 atmospheres and is lower than a set injection pressure of a fuel injection device provided in said combustion device. improvement device.
4. The combustion efficiency improvement according to any one of claims 1 to 3, wherein the nozzle has a stirring portion that generates a stirring flow in the fuel when the fuel at the predetermined pressure flows. Device.
The combustion efficiency improving device according to any one of claims 1 to 4, wherein the bubbles are ultra-fine bubbles having a particle size of less than 1 µm.
4. The nozzle according to claim 3, wherein the nozzle is arranged at a position such that the fuel travels a distance of no more than one minute for the fuel to reach the fuel injection device from the outlet of the nozzle. combustion efficiency improvement device.