JP2506599B2 - Powder fuel combustion device - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a combustion device. More specifically, powdery or granular solid fuel (hereinafter referred to as “powdered fuel”) obtained by compressing and crushing lumped solid fuel, industrial waste, household waste, etc., or obtained in the gas manufacturing process The present invention relates to improvements in combustion control performance of a combustion device when powder fuel as a by-product is burned and used as a heat source of a heat exchanger such as a boiler.

[0002]

2. Description of the Related Art Conventionally, as a combustion apparatus for powdered or granular powdered fuel, for example, Japanese Patent Publication No. 29299/1990, No.
The ones described in Japanese Patent Publication No. 27289 and Japanese Utility Model Publication No. 2-27291 are known.

In these conventional combustion devices, the powder fuel, which takes a long time to be heated, carbonized, ignited, and burned, is swirled in the combustion chamber together with the combustion air to prolong the air residence time of the fuel in the combustion chamber. We are aiming for complete and efficient combustion of powdered fuel.

In such a conventional combustion apparatus, complete combustion can be secured when the internal temperature of the combustion chamber is maintained at a high temperature by continuously burning for a long time, but the load of the heat exchanger to be connected is increased. Unlike the liquid fuel and the gas fuel, when it is required to adjust the combustion appropriately (increase / decrease or stop / start the supply of the powder fuel), it is not easy to adjust the combustion with the powder fuel flexibly and promptly. This problem is usually covered by using auxiliary fuel oil in parallel.

With respect to this point, however, there are some conventional techniques that enable stable combustion during low-power operation, such as Japanese Patent Laid-Open Nos. 2-259308 and 2-259309. However, these two techniques are both improvements in the burner device structure and do not use the conventional machine. When using a conventional machine to adjust combustion, the combustion will be interrupted if the temperature exceeds the prescribed upper limit temperature, and restarted if the temperature exceeds the prescribed lower limit temperature. When it takes a relatively long time, the internal temperature of the combustion chamber falls too much. Then, even if the burner is operated at the same time as the supply of the powdered fuel, there is a strong possibility that incomplete combustion will occur in the combustion chamber.

Further, in the prior art combustor in which fuel is powder, if the inner diameter and the length of the combustion chamber are expanded to the maximum for the purpose of improving combustion efficiency, the ejection of flame from the combustor becomes insufficient. There was a drawback that combustion ash was deposited in the combustor. As a result, not only the work to remove the incineration ash is required, but it also leads to the problem that the incineration ash accumulated further induces incomplete combustion in the long term.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-mentioned problems, and changes the fuel supply amount of powdered fuel in response to the load of the heat exchanger to be installed, and An object of the present invention is to provide a combustion device that ensures complete combustion of powder fuel. Another issue is the complete automation of combustion.

[0008]

In order to solve the above problems, the powder fuel combustion apparatus according to the present invention employs the following means. That is, in claim 1, the combustor for igniting and burning the powdered fuel / combustion air fed into the combustion chamber by the burner, the heat exchanger connected to the combustor, and the combustor and the heat exchanger are provided. When a load temperature sensor that detects the internal temperature of the heat exchanger and a combustion temperature sensor that detects the internal temperature of the combustion chamber are provided, and the load temperature sensor detects the minimum temperature, Ignites the burner via the controller,
Only when the combustion temperature sensor detects a temperature above the specified temperature, the fuel supply device is operated via the controller to supply fuel, and conversely when the load temperature sensor detects the upper limit temperature, the burner fuel supply device is stopped via the controller. The means characterized by doing is set.

According to a second aspect of the present invention, in the powder fuel combustion apparatus according to the first aspect, the combustion chamber is formed in a tubular shape and the axis line is set substantially horizontal, and the combustion chamber of the combustor is set. A burner cylinder having a dual structure of an inner cylinder and an outer cylinder connected coaxially, and a fuel guide cylinder connected at an acute angle to the axis of the outer cylinder of the burner cylinder and eccentrically from the axis. The inner cylinder is a flame nozzle having guide vanes for swirling flame inside, and the outer cylinder is a powder fuel / combustion air supply cylinder having guide vanes for swirling powder fuel and combustion air inside. The means characterized by that is set.

Further, in the temperature control method of the third aspect, the heat exchanger and the combustor are separately configured and connected to each other, and a signal is transmitted when the internal temperature of the heat exchanger drops to the lower limit temperature. When the internal temperature of the combustion chamber is equal to or lower than a predetermined temperature, the fuel is not sent to the combustion chamber, and when the internal temperature of the combustion chamber rises to the predetermined temperature, the fuel is sent to the combustion chamber. When the internal temperature of the combustion chamber is higher than a predetermined temperature, fuel is sent to the combustion chamber and at least combustion air is supplied, and conversely, when the internal temperature of the heat exchanger is higher than the upper limit temperature, at least the operation of the fuel supply device is stopped. The means characterized by

According to a fourth aspect of the present invention, in the powder fuel combustion apparatus of the second aspect, the diameter of the flame outlet on the heat exchanger side of the combustor is reduced to approximately 1/2 of the inner diameter of the main body of the combustion chamber. A means characterized in that the aperture was gradually reduced to form a funnel was adopted.

[0012]

According to the above-mentioned means, according to the invention of claim 1, when the internal temperature of the heat exchanger drops to the lower limit temperature, the load temperature sensor detects it and sends a signal to the controller, Ignites the burner, so the inside of the combustion chamber is heated. Therefore, the internal temperature of the combustion chamber surely rises. At the same time, the controller receives a signal from the combustion temperature sensor that detects the internal temperature of the combustion chamber at the time of burner ignition, and does not operate the fuel supply device when it is below a predetermined temperature, but sends a signal when the predetermined temperature is reached. The fuel supply device is operated to supply fuel into the combustion chamber. The burner may continue to inject the flame, or the combustion air may continue to be supplied but the burner may be deactivated at the time of starting the fuel supply device. Even if the operation is stopped, the powder fuel can be ignited as long as the temperature of the combustion chamber is equal to or higher than the predetermined temperature. When fuel is supplied in this way, the combustion chamber always reaches a predetermined temperature and is in an ideal state for combustion at all times, so that the powder fuel burns reliably and does not cause incomplete combustion. In this way, the combustion chamber raises its internal temperature, and the heat exchanger accordingly raises its internal temperature. When the load temperature sensor eventually detects the upper limit of the internal temperature of the heat exchanger, a signal is transmitted through the controller and at least the operation of the fuel supply device is stopped. Therefore, according to the present invention, the heat exchanger always maintains an ideal temperature range of a constant width, and there is no incomplete combustion, and the powder fuel is not wasted. Moreover, even if the powder fuel is used, the combustion can be adjusted promptly like liquid fuel or gas fuel, and the combustion can be easily automated.

According to the invention of claim 2, in addition to the action of claim 1, the flame is formed so as to blow against the combustion chamber to efficiently heat the combustion chamber, and the flame is swirled. However, complete combustion becomes more reliable because it does not hinder the swirling of the powdered fuel inside the combustion chamber.

Further, according to the invention of claim 3, since the heat exchanger and the combustor are configured separately and independently, combustion adjustment is basically facilitated only by that, and the internal temperature of the heat exchanger is predetermined. When the combustion is interrupted when the upper limit temperature is exceeded and restarted when the predetermined lower limit temperature is exceeded, if the time until the lower limit temperature is reached after the interruption of the combustion takes a relatively long time, the internal temperature of the combustion chamber drops extremely. In this case, the powder fuel is not supplied and only the burner is operated to heat the combustion chamber, and the internal temperature of the combustion chamber rises sufficiently to reach the ideal temperature (predetermined temperature). ), The fuel supply device is operated to supply the fuel, so there is no risk of incomplete combustion. Further, when the internal temperature of the heat exchanger reaches the upper limit temperature, the operation of the fuel supply device is stopped, so that there is no waste of fuel. And these combustion adjustments are easy to perform automatically.

Further, in the invention of claim 4, the diameter of the flame outlet on the heat exchanger side of the combustor is set to approximately 1 of the inner diameter of the main body of the combustion chamber.
Even if the inner diameter and length of the combustion chamber are expanded to the maximum for the purpose of improving combustion efficiency, the flow velocity of the powdered fuel can be reduced by gradually narrowing it down to a fineness of / 2 as shown in Fig. 1. The temperature can be adjusted without lowering the combustion temperature.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a combustion apparatus according to the present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of a combustion apparatus according to the present invention.

In this embodiment, a combustor 1 is shown which is equipped with a boiler type heat exchanger E consisting of a furnace Ea and a heat exchange water jacket Eb provided in the upper part of the furnace Ea.

A combustor 1 is connected to the furnace Ea of the heat exchange device E. The combustor 1 has a thin heat insulating material 11 as an exterior and a thick refractory material 12 having heat storage property inside, and is formed in a substantially cylindrical shape as a whole, and is installed with its axis being substantially horizontal. Inside the refractory material 12 is formed a combustion chamber 13 extending in a substantially horizontal direction. This combustion chamber 13 is a furnace E
A flame outlet 13a having a funnel-shaped diameter is provided on the connection side of a, and a funnel-shaped fuel supply port 13b having a small diameter is provided on the opposite side of the flame outlet 13a.

The burner cylinder 2 is connected to the fuel supply port 13b of the combustor 1. The burner cylinder 2 is formed in a double-walled cylindrical shape composed of an inner cylinder 21 and an outer cylinder 22 assembled in a concentric circular shape. The inner cylinder 21 is connected to the burner 3 to function as a flame nozzle cylinder, and is provided with a rotary vane-shaped guide vane 23 therein so that the flame can be swirled. The inner cylinder 21 is slightly shorter than the outer cylinder 22 on the fuel supply port 13b side. The rear portion of the outer cylinder 22, that is, the fuel supply port 1
At the opposite end of 3b, the guide cylinder 2 is formed at an acute angle with respect to the axis of the outer cylinder 22 in the fuel supply direction and at an angle eccentric to the coaxial line.
5 are connected (FIGS. 1 and 2). This guide tube 25
A fuel supply device 4 is connected to the fuel injection device, and powder fuel is injected and supplied together with compressed combustion air, and the outer cylinder 22 functions as a supply cylinder for powder fuel and combustion air. A fixed vane-shaped guide vane 24 is fixedly provided at the end on the side of the supply port 13b so that the powder fuel and the combustion air can be swirled.

The burner 3 mixes combustion air with liquid fuel or gaseous fuel and electrically ignites it to form a flame. The flame size is switched between two stages, and liquid fuel, Three types of switching are also possible, in which gaseous fuel is shut off and only combustion air is sent. Further, the fuel supply device 4 mixes powder fuel and combustion air and sends the mixture under pressure by a blower or the like.

A controller 5 is attached to each of these units. The controller 5 includes a load temperature sensor 51 attached to the heat exchange water jacket Eb of the heat exchanger E,
The combustion temperature sensor 52 attached to the combustion chamber 13, the load temperature sensor 51, the combustion temperature sensor 52, the burner 3, and the fuel supply device 4 are linked together. The load temperature sensor 51 detects the respective temperatures set at two points of the upper limit and the lower limit of the temperature range in which the heat exchanger E can efficiently exchange heat. Further, the combustion temperature sensor 52 detects an internal temperature (referred to as “predetermined temperature”) of the combustion chamber 13 suitable for combustion of the powdered fuel in the combustor 1. In this case, it is of course possible to set the predetermined temperature as a temperature at which the powder fuel is spontaneously ignited and burned without igniting the burner 3. The controller 5 reads the detection signals of the load temperature sensor 51 and the combustion temperature sensor 52,
It also has a microprocessor capable of instructing the burner 3 and the fuel supply device 4 to perform drive control in comparison with the lower limit temperature, the upper limit temperature and a predetermined temperature.

The controller 5 decelerates and stops the driving of the fuel supply device 4 when the heat exchange water jacket Eb of the heat exchanger E rises above the upper limit temperature, and conversely falls below the lower limit temperature. In such a case, the drive of the fuel supply device 4 is accelerated and started, and the burner 3 is extinguished when the temperature rises above a predetermined temperature in the combustion chamber 13, and conversely, the burner 3 is ignited when the temperature falls. Although it is possible to finely adjust the combustion state, in the present invention, the burner 3 and the fuel supply device 4 are controlled only based on the temperature range in the heat exchanger E, and the inside of the combustion chamber 13 is controlled. It does not depend on the temperature. Therefore, the internal temperature of the combustion chamber 13 drops below a predetermined temperature, and there is a period in which fuel is not supplied until it rises to a predetermined temperature, and during that period, the internal temperature of the heat exchanger E may continue to drop below the lower limit. Although it is theoretically true, when the lower limit temperature of the heat exchanger E is actually reached, the internal temperature of the combustion chamber 13 still maintains a high level, so there is no possibility that the internal temperature of the combustion chamber 13 will drop below a predetermined temperature. Therefore, the fuel supply device 4 is instantly activated at the same time when the lower limit temperature of the heat exchanger E is reached, and the powder fuel is burned by spontaneous ignition without activating the burner 3. Further, it is possible to use a microprocessor for the controller 5 so as to link start-up / shutdown of the entire apparatus and a safety device, etc., but as described in the claims, the combustor 1
When only the side control is performed, it is possible to simplify the controller 5 by adopting an electric relay instead of the microprocessor.

According to this embodiment, when starting up the entire apparatus, first, the burner 3 is started up to eject a large flame to heat the inside of the combustor 1 and raise the temperature of the combustion chamber 13 to a predetermined temperature. Let In this heating, since the flame is blown into the inside of the combustor 1 from the burner cylinder 2 like a nozzle, the thermal efficiency is extremely good and the heating time is short.

Next, the fuel supply device 4 is started to supply the powder fuel and the combustion air from the guide cylinder 25 of the burner cylinder 2 to the outer cylinder 22.

The powder fuel and the combustion air supplied are swirled by the mounting angle of the guide cylinder 25 to the outer cylinder 2 and the pressure feed to the space defined by the inner cylinder 21 and the outer cylinder 22 having the ring-shaped cross section. The swirled and swirling powder fuel / combustion air is ignited and burned by a large combustion flame sprayed from the inner cylinder 21 into the combustion chamber 13 while the swirling direction is further restricted by the guide vanes 24 fixed to the outer cylinder 22. The turning speed is also accelerated. Then, the powder fuel and the combustion air sent into the inside of the combustor 1 while combusting are narrow in the wide combustion chamber 13 of the combustor 1 and have a narrow fuel supply port 13b.
Through which the powder fuel is released, the swirling speed is further accelerated, the powder fuel is completely burned and efficiently burned, and the combustion flame is sprayed inside the furnace Ea of the heat exchanger E.

The furnace Ea of the heat exchanger E of the combustion chamber 13
Since the flame outlet 13a on the side is formed by reducing the diameter to about 1/2 of the inner diameter of the main body of the combustion chamber 13, it functions as a weir for powdered fuel and combustion air. As a result, it is possible to prevent the powdered fuel and the combustion air in the combustion chamber 13 from being blown out into the furnace Ea of the heat exchange device E without being completely burned and efficiently burned. Furthermore, even if the inner diameter and length of the combustion chamber are expanded to the maximum for the purpose of improving combustion efficiency, it is easy to reduce the flow rate of the powdered fuel, the combustion temperature, etc. with a single restriction of the flame outlet diameter. Can be adjusted. Moreover, by increasing the diameter of the flame outlet 13a, the ejection effect is enhanced.
The incineration ash is also ejected, which saves the trouble of cleaning the incineration ash accumulated in the combustion chamber and prevents incomplete combustion from being caused by the accumulated incineration ash in the long run.

After the powder fuel is ignited and burned in this way, the controller 5 controls whether the burner 3 is switched to form a small flame or to extinguish it. When the internal temperature of the heat exchanger E is higher than the upper limit temperature, the burner 3 is extinguished, only the combustion air is sent from the inner cylinder 21 as the secondary combustion air, and the fuel supply is interrupted. Since the guide vanes 23 provided on the inner cylinder 21 generate a swirling flow of the combustion air, it does not hinder the combustion or swirling of the powdered fuel burning inside the combustor 1.

4 to 5 show a second embodiment of the combustion apparatus according to the present invention.

In this embodiment, the combustor 1 can be connected in series by using the adapter 6 (FIG. 4), or the combustor 1 can be mass-produced in a unit type and connected / divided (FIG. 5). ). According to such an embodiment, the length of the combustion chamber 13 can be changed according to the load of the heat exchanger, and the combustion state of the powder fuel in the combustor 1 can be freely changed.

[0030]

As described above, the combustion apparatus according to the present invention is
According to the first aspect of the present invention, the temperature sensor and the controller can maintain the internal temperature of the heat exchanger within a constant ideal temperature range, can reliably prevent incomplete combustion, and further facilitate automatic control. is there.

Further, in addition to the effect of claim 1, in claim 2, the flame is formed so as to blow to the combustion chamber to efficiently heat the combustion chamber, and the flame is swirled to generate the flame. There is the effect that the swirling of the powdered fuel is not hindered inside the combustion chamber and efficient combustion can be secured.

Further, in claim 3, combustion adjustment is basically easy, and there is no possibility of incomplete combustion. Further, when the internal temperature of the heat exchanger reaches the upper limit temperature, at least the operation of the fuel supply device is stopped, so that there is no waste of fuel. Further, there is an effect that these combustion adjustments can be easily performed automatically.

Further, in claim 4, the powdered fuel and the combustion air in the combustion chamber 13 are prevented from being completely burned and not efficiently burned into the furnace Ea of the heat exchange apparatus E, and even if the combustion efficiency is high. Even if the inner diameter and the length of the combustion chamber are expanded to the maximum for the purpose of improvement, it is possible to easily adjust the flow velocity and the combustion temperature of the powder fuel without lowering it. Further, by narrowing the diameter at the flame outlet 13a, the ejection effect is enhanced, and the incineration ash is ejected, so that the labor of removing the incineration ash accumulated in the combustion chamber can be saved, and the incineration ash accumulated in the long-term can be used. This has the effect of preventing the induction of complete combustion.

[Brief description of drawings]

FIG. 1 is a sectional view showing a first embodiment of a combustion apparatus according to the present invention.

FIG. 2 is an enlarged vertical sectional view of a main part (burner cylinder) of FIG.

FIG. 3 is an enlarged cross-sectional view of a fuel supply port of a main part (burner cylinder) of FIG.

FIG. 4 is a side view of a main part (combustor) showing a second embodiment of the combustion apparatus according to the present invention.

FIG. 5 is a side view of a modification of the combustor of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Combustor 2 Burner cylinder 21 Inner cylinder 22 Outer cylinder 23, 24 Guide blade 3 Burner 4 Fuel supply device 5 Controller 51 Load temperature sensor 52 Combustion temperature sensor E Heat exchanger

Claims (4)

(57) [Claims] 1. A combustor for igniting and burning powder fuel / combustion air fed into a combustion chamber with a burner, a heat exchanger connected to the combustor, and the combustor and the heat exchanger connected to each other. In a combustion device comprising a controller, a load temperature sensor for detecting the internal temperature of the heat exchanger, and a combustion temperature sensor for detecting the internal temperature of the combustion chamber are provided, and when the load temperature sensor detects the lower limit temperature, the controller The burner is ignited via the controller, and the fuel supply device is operated via the controller to supply fuel only when the combustion temperature sensor detects a predetermined temperature or higher. Conversely, when the load temperature sensor detects the upper limit temperature, the controller is activated. The burner fuel supply device is stopped through the powder fuel combustion device. 2. A combustor in which a combustion chamber is formed in a tubular shape and an axis line is set substantially horizontal, and a burner cylinder having a double structure of an inner cylinder and an outer cylinder coaxially connected to the combustion chamber of the combustor. And a fuel guide tube connected at an acute angle to the axis of the outer tube of the burner tube and eccentrically from the axis, and the inner tube has a flame provided with guide vanes for swirling the flame. As a nozzle,
2. The powder fuel combustion apparatus according to claim 1, wherein the outer cylinder is a powder fuel / combustion air supply cylinder having therein a guide vane for swirling the powder fuel and combustion air. 3. The heat exchanger and the combustor are separately configured and connected to each other, and the two are connected to each other, and when the internal temperature of the heat exchanger drops to the lower limit temperature, a signal is transmitted to start the burner and burn the combustion. When the internal temperature of the chamber is lower than or equal to the predetermined temperature, the fuel is not sent to the combustion chamber, and when the internal temperature of the combustion chamber rises to the predetermined temperature, the fuel is sent to the combustion chamber, while the internal temperature of the combustion chamber is set to the predetermined temperature. When the temperature is equal to or higher than the temperature, the fuel is sent to the combustion chamber and at least the combustion air is supplied, and conversely, when the internal temperature of the heat exchanger is equal to or higher than the upper limit temperature, at least the operation of the fuel supply device is stopped. Temperature control method. 4. The diameter of the flame outlet on the heat exchanger side of the combustor is gradually reduced to a funnel shape so that it is approximately 1 of the inner diameter of the main body of the combustion chamber.
The powder fuel combustion device according to claim 2, wherein the powder fuel combustion device is formed to have a thickness of / 2.