JP2002098327A - Method for burning solid fuel and burner device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the decrease of thermal efficiency by effecting complete combustion of solid fuel, in a regenerative burner system. SOLUTION: A burner device 14 disposed on a furnace wall 12 partitioning a combustion space 10 is provided with first and second ventilation passages 20 and 22 with a fuel injection pipe 18 sandwiched therebetween. First the second fuel feed passages 26 and 28 to feed solid fuel are defined at the internal part of the fuel injection pipe 18. Heat storage bodies 46 are respectively disposed at the internal parts of the first and second ventilation passages 20 and 22. A combustion-supporting gas feed pipe 48 to feed combustion supporting gas to a combustion exhaust gas inflow space 50 communicates with and is connected to the inflow side of combustion exhaust to heat storage bodies 46 in the ventilation passages 20 and 22. Porous solid 52 to promote combustion of an unburnt substance contained in combustion exhaust gas is disposed in a ventilation passage running between the disposing position of the assisting gas necessary for combustion feed pipe 48 and the heat storage body 46.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a regenerative burner combustion system (hereinafter referred to as a "regenerative burner system") which uses solid fuel such as waste plastic, pulverized coal or carbonized sludge as a fuel. The present invention relates to a combustion method and a burner device.

[0002]

2. Description of the Related Art Metal melting furnaces, ladle for temporarily storing molten metal, tundish, melting equipment such as a pig iron storage furnace, or heating equipment for rolling solid metal and reheating it for forging, etc. As a means for heating the object, a regenerative burner system is suitably used. This system is, for example, a burner device provided with a fuel supply path provided in a central portion inside the main body, ventilation paths provided on both sides of the fuel supply path, and a heat storage body disposed in each ventilation path. Is used. That is, the fuel supplied from the fuel supply passage is burned by the combustion air supplied into the combustion chamber from one of the ventilation passages, and the regenerator is heated by discharging the combustion exhaust gas from the other ventilation passage. Next, by switching between the supply and exhaust of the two ventilation paths, the amount of heat stored in the heat storage body is recovered by the combustion air and returned to the combustion chamber. By repeating this switching in a short cycle of several tens of seconds to several minutes, the combustion air is preheated to a high temperature, and the combustion air is burned with high efficiency while recovering waste heat.

[0003]

As described above, in the method in which the supply of combustion air and the exhaust of combustion exhaust gas are switched by a single burner device, a part of the fuel may return to the ventilation passage without being burned. In addition, there is a problem that a part of the flame is directly sucked into the ventilation path together with the combustion exhaust gas, thereby lowering the thermal efficiency.

Here, as a method of treating waste plastic discarded as industrial waste or general waste, there is thermal recycling in which the waste plastic is burned as a fuel and the calorific value is recovered. Plastic uses petroleum as a main raw material and has combustion characteristics higher than that of coal, and even if it is waste plastic, it has a high commercial value from the viewpoint of fuel. Therefore, it is conceivable that the waste plastic is pulverized into fine particles, and this is used as a fuel for the regenerative burner system for effective utilization. However, with solid fuels such as pulverized coal or waste plastic fine particles, complete combustion in the combustion chamber is delayed compared to gas or liquid fuels, and the unburned components return to the ventilation path as described above, reducing thermal efficiency. There is a possibility that the situation may increase, and at present, it is not practically used as a regenerative burner device or a combustion system.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems inherent in the prior art, and has been proposed to appropriately solve the problem. The present invention provides a method for completely burning solid fuel in a regenerative burner system. An object of the present invention is to provide a solid fuel combustion method and a burner device that can prevent a decrease in thermal efficiency.

[0006]

[MEANS FOR SOLVING THE PROBLEMS]
In order to appropriately achieve the intended purpose, the solid fuel combustion method according to the present invention continuously supplies solid fuel from a fuel ejection pipe to a combustion space, and supplies the solid fuel from a first ventilation path provided with a heat storage body. The combustion air is supplied to the combustion space and the exhaust gas in the combustion space is exhausted from the second ventilation passage provided with the heat storage body. In a combustion method for burning fuel, a combustion supporting gas is supplied to a combustion exhaust gas inflow space into a regenerator in a ventilation path on a side from which the combustion exhaust gas is exhausted, thereby burning unburned components contained in the combustion exhaust gas. It is characterized in that it is made to be.

[0007] In order to solve the above-mentioned problems and to appropriately achieve the intended object, a burner device according to another invention of the present application comprises:
A fuel ejection pipe for supplying solid fuel to the combustion space, a plurality of ventilation paths provided outside the fuel ejection pipe to supply combustion air and exhaust combustion exhaust gas, and are disposed in each of the ventilation paths. In a burner device of a regenerative burner combustion system comprising a heat storage body and burning a solid fuel supplied from a fuel ejection pipe by alternately switching between supply and exhaust in the ventilation path, A supporting gas supply pipe for supplying a supporting gas is provided on the inflow side of the combustion exhaust gas, and the corresponding supporting gas supply pipe is connected to an air passage switched to exhaust the combustion exhaust gas. It is characterized by supplying gas.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a solid fuel combustion method and a burner apparatus according to the present invention will be described below with reference to the accompanying drawings by way of preferred embodiments.

FIG. 1 shows a schematic configuration of a regenerative burner system in which a solid fuel combustion method according to an embodiment is carried out. A burner device 14 is disposed on a furnace wall 12 defining a combustion space 10. Has been established. This burner device 14
The fuel injection pipe 18 is disposed at a center position of the main body 16, a first ventilation path 20 is formed on one side of the fuel injection pipe 18, and a second ventilation path 20 is formed on the other side. Road 22
Is formed. As shown in FIG. 2, the inside of the fuel ejection pipe 18 has a first plate corresponding to the first ventilation path 20 by a partition plate 24.
The second fuel supply passage 26 corresponding to the second air passage 22
And a fuel supply passage 28 of the same. At the front end of the partition plate 24 on the combustion space side, the ejection direction of the solid fuel ejected and supplied from the ejection port 26a of the first fuel supply passage 26 to the combustion space 10 is determined from the corresponding first ventilation passage 20. Combustion space 1
A first guide plate (guide means) 30 that guides the combustion air to be ejected and supplied to the combustion space 0 and an ejection port 28 a of the second fuel supply path 28 are also ejected and supplied to the combustion space 10. A second guide plate (guide means) for guiding the direction of jetting of the solid fuel to the direction of jetting of combustion air jetted and supplied to the combustion space 10 from the corresponding second ventilation path 22.
32 (see FIG. 3). Further, the partition plate 24
At the rear end portion of the fuel cell that is separated from the combustion space 10, a state in which the solid fuel supplied from the mixer 34 described later is supplied to the first fuel supply path 26 and a state in which the solid fuel is supplied to the second fuel supply path 28 And a two-way valve 36 for switching between the two.
The fuel jet pipe 18 employs a water cooling structure for circulating and supplying cooling water to the outer periphery of the fuel supply passages 26 and 28 for cooling.

As shown in FIG. 1, a rotary valve 40 is disposed in a storage silo 38 containing a solid fuel obtained by pulverizing waste plastic discarded as industrial waste or general waste to 3 mm or less. The solid fuel is cut out by the valve 40 and supplied to the weighing cut-out device 42. The weighing and cutting device 42 is provided with a rotary feeder 44 for constant volume cutting at the bottom thereof, and the solid fuel cut by the feeder 44 is supplied to the fuel ejection pipe 18.
Is supplied to a mixer 34 connected to the rear end of the mixer. The solid fuel is continuously supplied to the fuel ejection pipe 18 using the air supplied to the mixer 34 as a carrier gas.

Since the structure of the first air passage 20 and the structure of the second air passage 22 are the same, only the structure of the first air passage 20 will be described. Will be shown. That is, the first ventilation path 2
A heat storage body 46 made of a ceramic ball, a honeycomb body, a heat-resistant wire mesh, or the like is provided inside the inside of the combustion space 10, and when the combustion exhaust gas in the combustion space 10 is exhausted through the first ventilation path 20, The heat storage 46 is configured to be heated. Further, a combustion supporting gas supply pipe 48 is connected and connected to the side of the first exhaust passage 20 where the combustion exhaust gas flows into the heat storage body 46, and the combustion supporting gas is supplied from the supply pipe 48 to the combustion exhaust gas inflow space 50. It is configured. As the combustion supporting gas, for example, oxygen containing 20.9% vol or more may be used, and air or oxygen separated from air may be used.
The combustion supporting gas is supplied only to the ventilation passages 20 and 22 on the side from which the combustion exhaust gas is exhausted.

A porous solid 5 as a combustion promoting means for promoting the combustion of unburned components contained in the combustion exhaust gas is provided in an air passage between the position where the supporting gas supply pipe 48 is provided and the heat storage body 46.
2 are provided. The porous solid 52 is made of a ceramic honeycomb body or a heat-resistant wire mesh.
Those having an oxidation promoting component such as iO ₂ or V ₂ O ₅ or supported on the surface are suitably used. The combustion promoting means may have the same configuration as that of the heat storage body 46.

The first ventilation path 20 and the second ventilation path 22 are respectively provided on the outflow side of the combustion exhaust gas in each of the heat accumulators 46 via a four-way valve 54 for an air supply blower and an exhaust blower.
(Neither is shown) is connected. When the combustion air is supplied to the first ventilation passage 20 by switching the four-way valve 54, the combustion exhaust gas in the combustion space 10 is exhausted through the second ventilation passage 22, and conversely. When the combustion air is supplied to the second ventilation passage 22, the combustion exhaust gas in the combustion space 10 is set to be exhausted through the first ventilation passage 20. Further, the two-way valve 36 is switched in synchronization with the switching of the four-way valve 54, and the fuel supply passage 2 on the side corresponding to the ventilation passages 20 and 22 on the combustion air supply side.
The solid fuel is supplied to the mixers 6 and 28 from the mixer 34.

An auxiliary burner (not shown) for stabilizing ignition is provided in the combustion space 10, and the flame from the burner is set so as to come near the tip of the fuel injection pipe 18. Incidentally, as the auxiliary burner, a type in which fossil fuel is burned by combustion air is used.

[0015]

Next, the operation of the burner device according to the above-described embodiment will be described in relation to the combustion method. In addition,
By the two-way valve 36, the mixer 34 is connected to the first fuel supply path 2
6 and the four-way valve 54 connects the air supply blower to the first air passage 20 and the exhaust blower to the second air passage 22. Mixer 34 from the weighing and cutting device 42 via a rotary feeder 44
Is continuously supplied to the first fuel supply passage 26 in the fuel ejection pipe 18 by the carrier gas. In addition, the combustion air is supplied to the first ventilation path 20 via the four-way valve 54, and the air is ejected and supplied to the combustion space 10 to burn the solid fuel (the state of FIG. 1). .

The combustion exhaust gas from the combustion space 10 is
With the suction force of the exhaust blower communicating with the second ventilation path 22 via the direction valve 54, the air is sucked and exhausted by the second ventilation path 22. At this time, the heat storage body 46 provided in the second ventilation path 22 is heated.

After a predetermined time (after several tens of seconds to several minutes), the two-way valve 36 and the four-way valve 54 are switched synchronously, and the solid fuel continuously supplied from the mixer 34 is supplied to the second The fuel is supplied to the combustion space 10 through the fuel supply passage 28 and the combustion air is supplied to the combustion space 1 through the second ventilation passage 22.
The solid fuel is burned by being jetted and supplied to zero. At this time, the amount of heat stored in the heat storage body 46 of the second ventilation path 22 is recovered by the combustion air and returned to the combustion space. The exhaust gas from the combustion space 10 is supplied to the first ventilation path 2 by the suction force of the exhaust blower communicating with the first ventilation path 20.
It is sucked to zero and exhausted. At this time, the first ventilation path 2
The heat storage body 46 disposed at 0 is heated.

By alternately performing the above-described operation at intervals of several tens of seconds to several minutes, high-temperature combustion exhaust gas and combustion air alternately flow in the heat storage bodies 46 and 46 in a short cycle, thereby directly exchanging heat. Is performed, and a significant improvement in heat recovery efficiency is achieved.

During the operation of the regenerative burner system described above, solid fuel is ejected from the ejection ports 26a, 28a of the fuel supply paths 26, 28 in the direction in which the combustion air is ejected from the corresponding ventilation paths 20, 22. As supplied, efficient combustion of the fuel is achieved. The flame of this combustion is
Since the flame extends in a direction away from the other ventilation passages 20 and 22 that exhaust the combustion exhaust gas, a part of the flame is suppressed from being sucked into the ventilation passages 20 and 22 together with the combustion exhaust gas, and a decrease in thermal efficiency is prevented. Is done.

Here, in the case of using a solid fuel obtained by pulverizing waste plastics into fine particles, complete combustion in the combustion space is delayed, and it is inevitable that unburned components return to the ventilation passages 20 and 22. Therefore, in the embodiment, the flue gas inflow space 5 of the ventilation passages 20 and 22 on the side where the flue gas is exhausted.
0, a combustion supporting gas is supplied through the combustion supporting gas supply pipe 48, and the unburned portion of the solid fuel contained in the exhaust gas is efficiently burned. Therefore, the unburned portion contained in the combustion exhaust gas is completely burned before reaching the heat storage body 46, and a decrease in the heat recovery efficiency in the heat storage body 46 is prevented.

The unburned portion contained in the flue gas flowing into the flue gas inflow space 50 is the same as that of the porous solid 5.
The combustion is further promoted by the radiant heat or oxygen promoting function of No. 2, or by a short path prevented by the rectifying action when the combustion exhaust gas passes through the porous solid 52, so that the complete combustion of the unburned portion is more reliable. Is achieved. Since the porous solid 52 itself can be expected to have a heat storage effect, the porous solid 52 can also improve the heat recovery efficiency.

In the embodiment, the case where the waste plastic is used as the solid fuel has been described. However, the fuel is not limited to this, and may be pulverized coal, carbonized sludge of sewage sludge, carbide of waste, and the like. You may. In addition, the first ventilation path and the second ventilation path may be composed of a single passage,
It may consist of a plurality of passages. Further, the number of fuel supply passages divided in the fuel ejection pipe may be the same or half as the number of corresponding ventilation passages.

[0023]

As described above, in the method for burning solid fuel and the burner device according to the present invention, the combustion supporting gas is supplied to the combustion exhaust gas inflow space of the ventilation passage through which the combustion exhaust gas is sucked, thereby producing the exhaust gas. The unburned portion of the solid fuel contained in the fuel can be efficiently burned, and the fuel can be completely burned before reaching the heat storage body, thereby preventing a decrease in thermal efficiency. Further, by causing the combustion exhaust gas to pass through the combustion promotion means, the combustion of the unburned portion can be further promoted.

In addition, since the injection direction of the solid fuel injected and supplied from the injection port of the fuel supply path is directed to the injection direction of the combustion air from the corresponding ventilation path, efficient combustion of the solid fuel is achieved. Is achieved. In addition, since the flame of this combustion extends in a direction away from the other ventilation path that exhausts the combustion exhaust gas, a part of the flame is suppressed from being sucked into the ventilation path together with the combustion exhaust gas, and the decrease in thermal efficiency is reduced. Is prevented.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a regenerative burner system in which a solid fuel combustion method according to a preferred embodiment of the present invention is performed.

FIG. 2 is a sectional view of a main part of a fuel ejection pipe in the burner device according to the embodiment.

FIG. 3 is a front view of a fuel ejection pipe according to the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Combustion space 18 Fuel ejection pipe 20 First ventilation path 22 Second ventilation path 26 First fuel supply path 26a Spout port 28 Second fuel supply path 28a Spout port 30 First guide plate (guide means) 32 Second guide plate (guide means) 46 heat storage body 48 combustion supporting gas supply pipe 50 combustion exhaust gas inflow space 52 porous solid (combustion promoting means)

Claims (6)

[Claims] A solid fuel is supplied from a fuel discharge pipe to a combustion space.
(10), a supply of combustion air to a combustion space (10) from a first ventilation path (20) having a heat storage element (46), and a heat storage element (46). Combustion space (10) from the second ventilation path (22)
Exhaust exhaust gas from the inside and exhaust passages (20, 20)
22) A combustion method for burning solid fuel by alternately switching the supply and the exhaust of the combustion exhaust gas, wherein the combustion exhaust gas inflow space into the regenerator (46) in the ventilation path (20, 22) on the side exhausting the combustion exhaust gas. A method for burning solid fuel, characterized in that unburned components contained in combustion exhaust gas are burned by supplying a supporting gas to (50). 2. The combustion exhaust gas is passed through the ventilation passage (20, 22).
The method for burning solid fuel according to claim 1, wherein the fuel is passed through the heat accumulator (46) after contacting and passing through the combustion promoting means (52) provided in (2). 3. The combustion-supporting gas contains oxygen at 20.9% vo.
The solid fuel combustion method according to claim 1, wherein the amount of the solid fuel is at least 1. 4. A fuel ejection pipe (18) for supplying solid fuel to the combustion space (10), and a plurality of fuel ejection pipes provided outside the fuel ejection pipe (18) for supplying combustion air and exhausting combustion exhaust gas. Air passages (20, 22) and a heat storage body (46) disposed in each of the air passages (20, 22), and alternately switches between supply and exhaust in the air passages (20, 22). In a burner device of a regenerative burner combustion system for burning solid fuel supplied from a fuel ejection pipe (18), a support is provided on an inflow side of a combustion exhaust gas to a heat storage body (46) in each of the ventilation paths (20, 22). Supporting gas supply pipe for supplying flammable gas (48)
Are respectively disposed, and the ventilation passages (20,
22. The burner device according to 22), wherein the combustion supporting gas is supplied from a corresponding combustion supporting gas supply pipe (48). 5. The inside of the fuel ejection pipe (18) is divided into a plurality of fuel supply passages (26, 28), and the fuel outlets (2,
The guide means (30, 32) according to claim 4, further comprising guide means (30, 32) for directing the ejection direction of the solid fuel ejected and supplied from the corresponding air passage (20, 22) to the ejection direction of the combustion air from the corresponding ventilation path (20, 22). Burner device. 6. A combustion promoting means for promoting the combustion of unburned components contained in the combustion exhaust gas in an air passage between the position where the supporting gas supply pipe (48) is provided and the heat storage body (46). The burner device according to claim 4, wherein (52) is provided.