JP2001182935A - Method and device of effecting combustion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for effecting combustion to maintain a given combustion amount even when fuel such dry distillation gas as fluctuating in suppliable amount is burnt, and perform stable combustion. SOLUTION: This combustion method is a combustion method to regulate an amount of second fuel fed in a furnace 1 according to an amount of first fuel fed to the internal part of the furnace 1. Further, a combustion device comprises a furnace 1 to burn first fuel and second fuel, a means 10 to detect temperature in the furnace 1, and a controller 12 to regulate a feed amount of the second fuel based on the detecting value of the temperature detecting means 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion method for burning two kinds of fuels and an apparatus therefor.

[0002]

2. Description of the Related Art Incineration is often used for treating industrial waste and household waste. For example, industrial waste such as waste plastic is incinerated as follows. That is, industrial waste is put into a carbonization furnace, where a combustible gas, that is, a carbonization gas is generated from the industrial waste in the carbonization furnace, and the carbonization gas is incinerated in an incinerator.

[0003] Incidentally, in the above-mentioned carbonization furnace, the amount of carbonization gas generated is small at the start of operation and near the end thereof. For this reason, when burning the carbonization gas in the incinerator, the amount of combustion is insufficient, and the combustion temperature is lowered. In particular, when the combustion temperature falls below a predetermined temperature, there is a problem that harmful substances, for example, dioxin are generated. In addition, if the amount of combustion in the incinerator is insufficient, it is difficult to maintain stable combustion, and the amount of CO emission increases.

[0004] Further, when the combustion gas generated in the incinerator is used as a heat source to generate steam or hot water, or when the generated steam is used to generate electric power, and the energy is recovered as energy, the incineration is performed. If the amount of combustion fluctuates in the furnace, stable heat recovery cannot be performed.

[0005]

The present invention can maintain a predetermined amount of combustion even when burning a fuel whose supply amount fluctuates, such as carbonization gas,
An object of the present invention is to provide a combustion method and a device that enable stable combustion.

[0006]

Means for Solving the Problems The present invention has been made to solve the above-mentioned problems, and the invention according to claim 1 is based on the first fuel supply amount to the furnace. The supply amount of the second fuel to the fuel cell is adjusted.

According to a second aspect of the present invention, there is provided a combustion method for burning a first fuel and a second fuel in a furnace, wherein a supply amount of the second fuel to the furnace is determined based on a temperature in the furnace. It is characterized by adjusting.

According to a third aspect of the present invention, there is provided a combustion method for burning a first fuel and a second fuel in a furnace, wherein a supply amount of the second fuel into the furnace is adjusted to an oxygen concentration in the furnace. It is characterized in that adjustment is performed based on the above.

[0009] The invention according to claim 4 is characterized in that the first fuel is combustible waste.

According to a fifth aspect of the present invention, there is provided a furnace for burning the first fuel and the second fuel, a temperature detecting means in the furnace, and a supply amount of the second fuel based on a value detected by the temperature detecting means. And a controller for adjusting the pressure.

According to a sixth aspect of the present invention, there is provided a furnace for burning the first fuel and the second fuel, oxygen concentration detecting means in the furnace, and the second fuel based on the detection value of the oxygen concentration detecting means. And a controller for adjusting the supply amount.

Further, the invention according to claim 7 is characterized in that the furnace is provided with a burner to which the first fuel and the second fuel are supplied simultaneously or alternatively.

[0013]

Embodiments of the present invention will be described below. The present invention can be suitably implemented in a combustion device that burns the first fuel and the second fuel.
And this combustion apparatus can be applied to an incinerator and a boiler.

Here, the first fuel is a fuel that needs to be preferentially burned, and is, for example, combustible waste. This combustible waste is combustible gas generated from industrial waste, household waste, or the like by a carbonization furnace or a semi-carbonization furnace, that is, a carbonization gas. Also, heatable waste is
It also includes digestive gas generated during fermentation or brewing processes and decomposition of garbage by microorganisms, and low-concentration alcohol generated during alcohol distillation. On the other hand, the second fuel is a fuel that can be supplied more stably than the first fuel, for example, a general fuel such as a liquid fuel such as heavy oil, light oil or kerosene, or a gas fuel such as city gas or propane;
That is, it is a normal fuel.

The combustion device includes a furnace to which the first fuel and the second fuel are supplied, and means for adjusting a supply amount of the second fuel. Then, the supply amount adjusting means adjusts the supply amount of the second fuel according to the supply amount of the first fuel into the furnace. That is, when the supply amount of the first fuel to the furnace is small, the supply amount of the second fuel is increased, and when the supply amount of the first fuel is large, the supply amount of the second fuel is decreased. Here, when the supply amount of the first fuel is a supply amount sufficient to obtain a predetermined combustion amount, the supply amount of the second fuel is set to “0”, and when the supply amount of the first fuel is “0”, The supply amount of the second fuel is adjusted to a supply amount sufficient to obtain a predetermined combustion amount.

Therefore, according to the present invention, the combustion amount in the furnace can be maintained at a predetermined combustion amount irrespective of a change in the supply amount of the first fuel, and stable combustion can be performed. Moreover, since the amount of combustion in the furnace is kept constant, the combustion temperature in the furnace can be kept constant. Therefore, generation of harmful substances such as dioxin can be prevented. Further, since the combustion in the furnace is stabilized, the amount of CO emission can be suppressed and the generation of black smoke can be prevented.

Further, the present invention has a structure in which a temperature detecting means in the furnace is provided, and a controller for controlling the second fuel supply amount adjusting means based on a detected value of the temperature detecting means is provided. Can be. That is, the amount of combustion in the furnace is detected as the temperature in the furnace, and the supply amount of the second fuel is adjusted according to this temperature.

That is, when the supply amount of the first fuel into the furnace changes, the combustion amount by the first fuel changes.
The temperature in the furnace also changes. Therefore, the supply amount of the second fuel can be adjusted so as to maintain the predetermined combustion amount by detecting the temperature in the furnace.

Further, the present invention provides a structure in which an oxygen concentration detecting means in the furnace is provided, and a controller for controlling the second fuel supply amount adjusting means based on a detection value of the oxygen concentration detecting means is provided. You can also. That is, the combustion amount in the furnace is detected as the oxygen concentration in the furnace, and the supply amount of the second fuel is adjusted according to the oxygen concentration.

That is, the furnace is supplied with an amount of air (actually, air is supplied slightly more) necessary to completely burn the first fuel and the second fuel. The combustion of the first fuel and the second fuel consumes oxygen in an amount corresponding to the supply amount of each of these fuels. Therefore, the amount of combustion in the furnace can be detected by detecting the oxygen concentration in the furnace. Therefore, by detecting the oxygen concentration, the supply amount of the second fuel can be adjusted so as to maintain the predetermined combustion amount.

Further, in the present invention, a burner to which the first fuel and the second fuel are supplied simultaneously or alternatively, that is, a co-firing burner is provided in the furnace, and the first fuel and the second fuel are the same. Through the furnace. Such a co-firing burner is extremely suitable for carrying out the present invention.

That is, in the present invention, since the supply amount of the second fuel is adjusted according to the change in the supply amount of the first fuel, the burners dedicated to burn the first fuel and the second fuel respectively are used. Is required, it is necessary to increase the rate of change of the amount of combustion in each burner (that is, the turndown ratio), and if this turndown ratio is increased, the combustibility tends to decrease. On the other hand, when the mixed burner is used, the combustion amount in the mixed burner can be maintained substantially constant even if the ratio of the supply amount of the first fuel to the supply amount of the second fuel changes, so There is no need to increase the down ratio, thereby improving the combustibility. In addition, the use of the co-firing burner eliminates the need to provide a separate burner for burning each of the first fuel and the second fuel, and can simplify the control of the burner.

Further, in the present invention, since the combustion amount and the combustion temperature can be kept constant as described above, if a heat recovery means is provided downstream of the furnace, the heat recovery The amount of heat recovered by the means is stabilized, and stable heat supply from the heat recovery means becomes possible. Here, when the heat recovery means is provided, the supply amount of the second fuel may be adjusted based on the heat supply amount from the heat recovery means or the heat recovery amount in the heat recovery means. . That is, the heat supply amount and the heat recovery amount of the heat recovery means change according to the combustion amount of the furnace. Here, the heat supply amount and the heat recovery amount of the heat recovery unit are:
The steam and the hot water from the heat recovery means are detected based on the flow rate, temperature and pressure thereof.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic explanatory view for explaining an embodiment of the present invention. Here, in this embodiment, the first fuel is a carbonized gas and the second fuel is a normal fuel such as propane gas. Also, this embodiment
This is an example applied to an incinerator that incinerates the first fuel, that is, the carbonization gas.

In FIG. 1, the furnace 1 is provided with a burner 2 on the upstream side (left side in FIG. 1). This burner 2
Is a so-called co-firing burner in which the carbonization gas and the normal fuel are supplied simultaneously or alternatively and burned. Therefore, the burner 2 has the first fuel line 3 and the second fuel line 4
And the air supply line 5 are connected to each other.

At the upstream end of the first fuel line 3, a carbonization furnace 6 is provided. The carbonization furnace 6 generates carbonized gas from the industrial waste charged therein.

A fuel tank (not shown) as a normal fuel supply source is connected to the upstream end of the second fuel line 4. In the middle of the second fuel line 4, a supply amount adjusting means 7 is provided. As the supply amount adjusting means 7, for example, a flow rate adjusting valve or a variable flow rate pump can be used.

An exhaust gas passage 8 for discharging combustion gas generated in the furnace 1 as exhaust gas is connected to the downstream side of the furnace 1 (right side in FIG. 1). A heat recovery means 9 is provided in the exhaust gas passage 8. In this embodiment, the heat recovery means 9 is an exhaust gas boiler that uses the exhaust gas from the furnace 1 as a heat source and generates steam.

Further, the furnace 1 is provided with a temperature detecting means 10.
Is provided. The temperature detecting means 10 is provided in the furnace 1
On the downstream side in the furnace, the furnace 1 is arranged to detect the temperature inside the furnace 1. And the temperature detecting means 1
0 is connected to the controller 12 via the line 11.
The controller 12 controls the supply amount adjusting means 7 based on a detection signal from the temperature detecting means 10.

Next, the control contents of the controller 12 will be specifically described. First, industrial waste is put into the carbonization furnace 6, and the operation of the carbonization furnace 6 is started.
The burner 2 is activated around the start of the operation of the carbonization furnace 6. That is, the normal fuel is supplied to the burner 2 from the second fuel line 4 and the air is supplied from the air supply line 5 to start the burner 2. At this time, the supply amount of the normal fuel to the burner 2 is:
The amount of air supplied to the burner 2 is slightly larger than the amount of air required for complete combustion of the normal fuel supply at this time.

First, immediately after the start of the operation of the carbonization furnace 6, there is almost no generation of carbonization gas.
Combustion starts only with normal fuel. The combustion of the normal fuel heats the inside of the furnace 1 to a temperature at which stable combustion is performed even when the carbonization gas is supplied.

After the operation of the carbonization furnace 6 starts, if the amount of carbonization gas generated in the carbonization furnace 6 increases with the passage of time, the carbonization gas is supplied to the first fuel line 3.
Starts to be supplied to the burner 2. Therefore, in the furnace 1, the carbonization gas starts burning in addition to the normal fuel. Then, since the amount of combustion in the furnace 1 increases, the temperature in the furnace 1 increases. When the temperature in the furnace 1 rises, the controller 12
The supply amount adjusting means 7 is controlled based on the detected value from 0 to reduce the supply amount of the normal fuel, thereby adjusting the combustion amount to a predetermined amount.

When the carbonization gas starts to be actively generated in the carbonization furnace 6, the amount of the carbonization gas is substantially stabilized. In a state where the amount of generated carbonized gas is stable, the amount of supplied carbonized gas to the burner 2 is sufficient to obtain a predetermined combustion amount.
2 controls the supply amount of the normal fuel to “0” by controlling the supply amount adjustment unit 7 based on the detection value from the temperature detection unit 10. Here, even when the amount of generated carbonized gas is substantially stable, if the supply amount of the carbonized gas to the burner 2 decreases, the controller 12 performs the control based on the detection value from the temperature detecting unit 10. By controlling the supply amount adjusting means 7, the supply amount of the normal fuel is increased.

When the operation of the carbonization furnace 6 is about to end, and the amount of carbonized gas generated starts to decrease, the amount of carbonized gas supplied to the burner 2 decreases, and the amount of combustion decreases. The temperature in the furnace 1 decreases. Then, the controller 12 controls the supply amount adjusting means 7 based on the detected value of the temperature detecting means 10 to adjust the supply amount of the normal fuel to a predetermined combustion amount. When the operation of the carbonization furnace 6 is completed, the supply amount of the carbonization gas to the burner 2 becomes “0”.
Is supplied with only normal fuel, and a predetermined amount of combustion is maintained by burning the normal fuel.

As described above, in this embodiment, the burner 2 is controlled in accordance with the amount of the dry distillation gas supplied to the burner 2.
In order to adjust the amount of normal fuel supplied to the burner 2, it is possible to maintain a constant amount of combustion in the furnace 1 and a constant combustion temperature regardless of a change in the amount of dry distillation gas supplied to the burner 2. it can. Therefore, generation of harmful substances can be prevented, and CO emissions can be suppressed. Moreover, in this embodiment, since the combustion amount and the combustion temperature can be kept constant, stable heat recovery can be performed in the heat recovery means 9, and further, the supply of heat from the heat recovery means 9. Is performed stably.

In this embodiment, since the burner 2 is a so-called co-firing burner, the combustion amount can be maintained substantially constant even if the ratio between the supply amount of the dry distillation gas and the supply amount of the normal fuel changes. Therefore, it is not necessary to increase the turndown ratio, and the flammability can be improved. Moreover, by using a co-fired burner as the burner 2, it is not necessary to provide a separate burner for burning each of the carbonized gas and the normal fuel, and the control of the burner can be simplified.

In this embodiment, instead of the temperature detecting means 10, the supply amount adjusting means 7 may be controlled based on the oxygen concentration in the furnace 1. That is, as shown in FIG. 1, an oxygen concentration detecting means 13 is provided in the furnace 1, and the oxygen concentration detecting means 13 is connected to the controller 12 via the line 11. Then, the controller 12 adjusts the supply amount of the normal fuel based on the detection value from the oxygen concentration detecting means 13. That is, when burning the carbonization gas or the normal fuel, an amount of oxygen corresponding to the supply amount is consumed, so that it is possible to detect the combustion amount in the furnace 1 based on the oxygen concentration in the furnace 1. it can. Therefore, by detecting the oxygen concentration in the furnace 1, the supply amount of the normal fuel can be adjusted so as to maintain the predetermined combustion amount.

Further, in this embodiment, the supply amount of the normal fuel to the burner 2 may be adjusted based on the heat supply amount from the heat recovery means 9. That is, a steam flow rate detecting means 15 is provided in the steam line 14 of the heat recovery means 9, and the steam flow rate detecting means 15
Is connected to the controller 12 via a line 11. The controller 12 controls the steam flow rate detecting means 15.
The supply amount adjusting means 7 is controlled based on the detected value from the control unit. That is, since the heat recovery means 9 uses the high-temperature combustion gas generated in the furnace 1 as a heat source, the amount of steam generated according to the flow rate and temperature of the combustion gas flowing from the furnace 1 into the heat recovery means 9 Changes. Since the flow rate and temperature of the combustion gas change according to the amount of fuel in the furnace 1, the amount of combustion in the furnace 1 can be detected based on the flow rate of steam from the heat recovery means 9.

Further, instead of providing the steam flow rate detecting means 15, a steam pressure detecting means 16 is provided in the heat recovery means 9, and the steam pressure detecting means 16 is connected to the controller 12 via a line 11, The supply amount adjusting means 7 may be controlled based on the steam pressure in the heat recovery means 9. The control in this case is the same as the control by the steam flow rate detecting means 15, so that the detailed description will be omitted.

Further, although detailed drawings are omitted, when the present invention is applied to a boiler, it is configured as follows.
That is, the co-firing burner 2 in the embodiment is used as a burner of a boiler, and at least one of the temperature detecting means 10 and the oxygen concentration detecting means 13 is provided in a furnace of the boiler, that is, a combustion chamber or a flame forming part. In this case, a steam flow rate detecting means 15 is provided in the steam line of the boiler, or a steam pressure detecting means 16 is provided in the boiler, and the supply amount of the normal fuel is determined based on a detection value from each of these detecting means. It can also be configured to adjust. Further, the boiler is not limited to a steam boiler, but includes a hot water boiler, a heat medium boiler, and the like. When the boiler is a hot water boiler or a heat medium boiler, a flow rate and a temperature of a fluid to be heated (water and a heat medium liquid) after the heating from the boiler are detected, and based on the detected values of the flow rate and the temperature, a normal operation is performed. The fuel supply amount is adjusted.

[0041]

According to the present invention, a predetermined amount of combustion can be maintained and stable combustion can be performed even when burning a fuel whose supply amount fluctuates, such as carbonization gas. Further, since a predetermined amount of combustion can be maintained, the combustion temperature can be stabilized, and generation of harmful substances can be prevented.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory diagram illustrating an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace 2 Burner 10 Temperature detecting means 12 Controller 13 Oxygen concentration detecting means

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (reference) F23G 7/06 105 F23G 7/06 105 F term (reference) 3K003 DA09 EA10 FA01 FA04 FB05 FC04 FC05 GA03 HA03 HA04 3K062 AA23 AB02 AC01 AC13 AC19 DA01 DA07 DA14 DA22 DA32 DB01 DB05 3K065 AA23 AB02 AC01 AC13 AC19 BA02 BA04 QB03 QB13 3K078 AA02 AA04 BA02 BA03 BA13 BA15 BA22 BA26 CA03 CA11 CA21 3K091 AA03 AA06 BB02 BB06 BB26 CC24 CC07 CC23 CC24 CC24 CC02

Claims (7)

[Claims] 1. A combustion method comprising adjusting a supply amount of a second fuel into the furnace 1 according to a supply amount of a first fuel into the furnace 1. 2. A combustion method for burning a first fuel and a second fuel in a furnace 1, wherein a supply amount of a second fuel to the furnace 1 is adjusted based on a temperature in the furnace 1. Combustion method characterized by the above-mentioned. 3. A combustion method for burning a first fuel and a second fuel in a furnace 1, wherein a supply amount of a second fuel to the furnace 1 is adjusted based on an oxygen concentration in the furnace 1. A combustion method characterized in that: 4. The combustion method according to claim 1, wherein the first fuel is combustible waste. 5. A furnace 1 for burning a first fuel and a second fuel
And a controller 12 for adjusting a supply amount of the second fuel based on a detected value of the temperature detecting means 10 in the furnace 1 and a detected value of the temperature detecting means 10. 6. A furnace 1 for burning a first fuel and a second fuel
And a controller 12 for adjusting the supply amount of the second fuel based on the detected value of the oxygen concentration detecting means 13 in the furnace 1 and the detected value of the oxygen concentration detecting means 13. 7. The combustion according to claim 5, wherein the furnace 1 is provided with a burner 2 to which the first fuel and the second fuel are supplied simultaneously or alternatively. apparatus.