JP2000039125A - Recombustion analysis type reburning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure which enables separate evaluation of the effect of thermal reaction and the effect of other chemical reactions (oxidation/reduction and the like) for the optimization of a reburning device for a combustion apparatus for wastes and such as boiler. SOLUTION: In a reburning device for reburning a combustion gas G generated in a main combustion chamber 54a of a combustion apparatus is constituted of a gas inlet part 18 into which the combustion gas G flows, a reburning chamber 20 to return the combustion gas G flowing in, a reburning triggering means 26 to trigger the reburning of the combustion gas G in the reburning chamber 20, a gas outlet part 24 to release the combustion gas G from the reburning chamber 20, a bypass pipe 28 so arranged to have an inflow end 28a near the gas inlet part 18 while having an outflow end 28b outside the reburning chamber 20 near the gas outlet part 24. The combustion gas G flowing in is shunted in two directions into the reburning chamber 20 and into the bypass pipe 28. It is so arranged that thermal reaction and other chemical reactions act in the reburning chamber 20 and the thermal reaction alone acts in the bypass pipe 28. The combustion gases to be released from the gas outlet part 24 and an outflow end 28b undergo a contrast analysis to evaluate actions of both types of reactions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reburning analysis type reburning apparatus capable of analyzing the mechanism of reburning of combustion gas and the like, and clarifies the basic mechanism of reburning of combustion gas. It is mainly used for experiments for experiments, operation control of reburning devices provided in waste incinerators and the like, and reburning of combustion gas from waste combustion furnaces and boilers.

[0002]

2. Description of the Related Art Generally, nitrogen oxides (NO) are contained in combustion gas discharged from a combustion device such as a waste incinerator or a boiler.
x), various components such as carbon monoxide (CO) and hydrocarbons (HC), and so-called reburning in which the combustion gas is reburned in order to burn these contents more completely. A method has been developed and is available for use.

FIG. 5 shows an example of a conventional waste incinerator equipped with this kind of reburning apparatus. In FIG. 5, reference numeral 50 denotes a waste incinerator, 51 denotes a hopper, 52 denotes a pusher, and 53 denotes a pusher. Stalker, 54a a main combustion chamber, 54b a combustion chamber, 55 a waste heat boiler, 56 an exhaust gas purification device, 57
Is an induction blower, 58 is a chimney, 59 is a mixed gas supply nozzle, 60 is a secondary air supply nozzle, 61 is a mixer, 62 is a recirculating gas blower, 63 is a natural gas supply source, 64 is a secondary air blower, 65 Is a slag cooling tank, A is secondary air, B is waste, C is a mixed gas of natural gas and recirculated gas, N is natural gas, G is combustion gas, G _O is recirculated gas, and F is combustion residue. It is.

[0004] The waste B supplied from the hopper 50 into the furnace body by the pusher 52 is supplied with primary combustion air (not shown) from below the stoker 5 to dry stoker 53a, combustion stoker 53b and post-combustion. Combustion residue F generated by the combustion is sequentially taken out through the stoker 53c and taken out of the slag cooling tank 65 as granulated slag. The combustion gas G generated in the main combustion chamber 54a by the combustion of the waste B is supplied to the induction blower 57.
As a result, it is drawn out of the furnace main body through the combustion chamber 54b, the waste heat boiler 55, the gas purification device 56 and the like, and is discharged from the chimney 58 to the atmosphere.

The combustion gas G generated in the main combustion chamber 54a on the stoker 53 rises in the combustion chamber 54b in the direction indicated by the arrow A as described above. into G, a gas mixture C of natural gas N and recycle gas G _O is supplied from the mixed gas supply nozzle 59.

[0006] The combustion gas G mixed with the mixed gas C is drawn.
Then, it rises and is almost at the center of the combustion chamber 54b (reburning).
In the part R) further into the inside from the secondary air nozzle 60
Secondary air A is supplied. Due to the mixing of the secondary air A
The combustion gas G containing the mixed gas C flows to the reburning part R.
In the so-called reburn, as a result, the combustion gas
G and recirculated gas G _ONOx and CO contained in
Various incompletely burned substances such as HC will be reburned.
You. In addition, incomplete fuel contained in the reburning part R
The combustion gas G from which the burned material has been almost completely burned is passed through the aforementioned gas.
Exhaust gas purifier 5 consisting of dust collector, bag filter, etc.
After the NOx component and SOx component are removed in 6,
Safe CO_TwoAnd H_TwoExhaust gas containing complete combustion components such as O
And is discharged into the atmosphere.

[0007]

In the reburning apparatus shown in FIG. 5, a considerable amount of incompletely combusted substances contained in the combustion gas G can be reburned, and excellent practical utility is obtained. Is played. However, at the conventional reburning device, since the reaction mechanism of the reburning have been manufactured and sold as a reburning device remain not fully understood, natural gas N or recycle gas G _O, 2
The supply amount of the secondary air A and the supply position thereof are also largely determined by so-called experience and intuition.
The automatic operation of a stable reburning device has not been able to be performed constantly and easily.

That is, in the reburning apparatus, CO 2
Must be converted to CO ₂ , and various hydrocarbons (HC) must be decomposed into H ₂ O and CO ₂ , and the inside of the apparatus is mixed with oxidation, reduction, and thermal reactions. It is. However, among them, it is hardly considered which reaction is most effective for reburning.

For example, if a thermal reaction is most effective for reburning, the reburning section R may be mainly concerned with a heating reaction. Further, if the oxidation / reduction reaction is effective for reburning, the reburning portion R may be constituted mainly by the oxidation / reduction reaction. However, conventionally,
As described above, since the reburning device was configured without elucidating the elementary process of such a reaction, the gas released from the outlet of the reburning device was analyzed, and the reburning efficiency was determined consequently. There is no other method than this, and it causes many problems in designing a reburning device such as a waste incinerator and controlling its operation.

[0010]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a reburning analysis type reburning apparatus according to the present invention is produced in a main combustion chamber of a combustion apparatus. In a reburning device for reburning the burned combustion gas, a gas inlet portion into which the combustion gas flows, a reburning chamber for reburning the flowing combustion gas, and reburning of the combustion gas in the reburning chamber Reburning generating means, a gas outlet for discharging combustion gas from the reburning chamber, and a bypass having an inflow end near the gas inlet and an outflow end outside the reburning chamber near the gas outlet. The combustion gas flowing from the gas inlet is divided into two directions, the recombustion chamber and the bypass pipe, and the combustion gas discharged from the gas outlet and the outlet of the bypass pipe can be compared and analyzed. And it has a.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, a bypass pipe is arranged in a reburning chamber for reburning an inflowing combustion gas,
The combustion gas flowing from the gas inlet is divided into two directions, that is, the combustion gas and the bypass pipe. The combustion gas that has flowed into the reburning chamber undergoes various chemical reactions (eg, oxidation and reduction reactions) and thermal reactions. Since the fuel for reburning is injected into the reburning chamber and the air for reburning is also injected, the combustion gas reacts with the fuel again, and the generated heat promotes various chemical reactions. become. Then, it is finally discharged as a completely burned combustion gas, and after the denitration and desulfurization, is released into the atmosphere.

On the other hand, the combustion gas that has flowed into the bypass pipe is discharged without receiving any injection of reburning fuel or air. By the way, since the bypass pipe is disposed in the reburning chamber, the temperature of each part of the bypass pipe should match the temperature of the corresponding position in the reburning chamber.
Therefore, the combustion gas flowing through the bypass pipe undergoes only a thermal reaction under the heating condition at this temperature.

That is, the gas discharged from the reburning chamber is a gas which has undergone a thermal reaction and another chemical reaction, but the gas discharged from the bypass pipe is a gas which has undergone only a thermal reaction. . That is, it is possible to analyze the influence of other chemical reactions from the difference in the physical properties and the like of the two types of exhaust gas. In addition, this makes it possible to determine the type and amount of fuel injected into the reburning chamber and the best mode of the amount of air injected. Since these quantities are also affected by the shape of the reburning chamber and the piping condition of the bypass pipe, a thorough study is required in determining the best mode.

In the above-described example, the fuel injection section for reburning and the air blowing section serve as reburning generating means. However, only one of the reburning generating means may be used. For example, if the combustion gas is in a state of lack of oxygen, it may be possible to achieve complete combustion only by blowing air, and if there is an excess of oxygen, it may be sufficient to simply inject fuel. It is.

In the case where both the fuel injection section and the air blowing section are provided, if both means are provided at substantially the same position in the reburning chamber, even if the purpose of complete combustion of the combustion gas can be achieved, the combustion gas can also be obtained. There is a weak point that the complete combustion process of combustion gas cannot be sufficiently elucidated because fuel is also burned simultaneously.
Therefore, the fuel injection section is provided near the gas inlet section, the air blowing section is provided at an intermediate position of the combustion chamber, and the gas inlet side of the air blowing section is in the reduction area, and the gas outlet side of the air blowing section is in the oxidizing area. Can be separated. In addition, only the fuel such as natural gas may be injected from the fuel injection portion, or a mixed fluid of the fuel such as natural gas and a part of the gas discharged from the reburning chamber (recirculated gas) may be injected. You may.

In the reduction region, the combustion gas becomes excessive in fuel, the injected fuel burns, and the heat generated thereby raises the temperature of the combustion gas. In the oxidation region, not only the unburned fuel is oxidized, but also the incompletely combusted substances of the combustion gas. Further, the oxidation of the combustion gas proceeds by the generated heat throughout the entire region, and complete combustion of the combustion gas is achieved in the reburning chamber.

In order to examine these reactions, sampling means for extracting combustion gas can be provided at a desired position in the reburning chamber or the bypass pipe. Specifically, for example, if a small tube having a valve is inserted, the valve can be opened to sample the combustion gas at each location. From the result of the analysis of the reburning by the sampling, if the inflow amount of the gas inlet, the fuel injection unit and the air blowing unit is made variable, the reburning process can be freely controlled.
If sampling, gas analysis, and the opening / closing amount of each part are computer-controlled, a series of steps can be automated.

Further, the reburning analysis type reburning apparatus can be applied as a so-called reburning test apparatus, and of course, in parallel with the reburning analysis type reburning apparatus on the outside of the combustion chamber of a waste incinerator. A reburning chamber and a bypass pipe etc. of the device are provided, and based on the analysis value of each exhaust gas from the gas outlet of the reburning chamber and the gas outlet end of the bypass pipe, the fuel and The blowing amount of the secondary air may be automatically controlled.

Further, in the reburning analysis type reburning apparatus, the combustion chamber itself of the waste incinerator is used as a reburning chamber, a bypass pipe is disposed in the inside thereof, and a fuel injection section and a secondary air injection section are provided. By providing it in the combustion chamber, a reburning analysis type reburning device for a waste incinerator can be provided.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a simplified cross-sectional view of a first embodiment of the present invention, showing a case where the present invention is utilized as a part of a so-called reburning test device or a control device of a reburning device provided in a waste incinerator. Things. Referring to FIG. 1, in a main combustion chamber 54 a such as a waste incinerator combustion chamber or a boiler combustion chamber, wastes, fuel, and the like are burned, and generated combustion gas G is supplied from a gas inlet 18 of a reburning device 16. It flows into the reburning chamber 20. That is, the reburning chamber 20 is formed by the surrounding wall 22, and the combustion gas 14 is discharged from the gas outlet 24.

The surrounding wall 22 forming the reburning chamber 20 has
The measuring holes 2, 3,...
Has been established. In addition, opening and closing valves are provided in the measurement holes 2 to 10.
Bu V _Two~ V_TenIs attached, and the combustion gas G
These leaks are prevented.

In the reburning chamber 20, a reburning means 26 for reburning the combustion gas G is constituted by a fuel injection section 26a, an air blowing section 26b and the like. That is, one end of the fuel injection portion 26a extends outside the reburning chamber, and the other end extends to the position of the measurement hole 3. Further, in the present embodiment, methane is used as fuel, and the air blowing portion 26b is also used as the measurement hole 7. In addition, it is also possible to use LNG or a mixed gas of LNG and recirculated gas which is a part of the combustion gas as the fuel.

A bypass pipe 28 is disposed in the reburning chamber 20, and its inflow end 28 a reaches the vicinity of the gas inlet 18. The outflow end 28b is drawn out of the reburning chamber 20 near the gas outlet 24.

Next, the operation of the reburning device according to the configuration of FIG. 1 will be described. The combustion gas G flowing into the reburning chamber 20 from the gas inlet 18 flows in the reburning chamber 20 in the direction of the arrow. When methane gas is supplied from the fuel injection portion 26a, the methane gas is burned near the measurement hole 3, which is the outlet, and the combustion gas G is reburned (reburning) by the combustion heat of the methane, and the gas temperature rises.

The area from the measurement hole 3 to the measurement hole 7 is
Since the fuel becomes excessive as a whole, it is called a reduction region 30. In addition, from the measurement hole 7 to the gas outlet 24, fresh secondary air is supplied from the air blowing portion 26b, so that the region becomes an oxygen-excess oxidized region 32.

In the oxidizing region, unburned methane remaining in the combustion gas G from the reducing region 30 is burned to a higher temperature, and as a result, the temperature of the combustion gas G further increases. Therefore, the combustion gas G is completely burned through heating in the reduction region 30 and the oxidation region 32, and additionally, in the oxidation region 32, the combustion gas G reacts with oxygen.
More complete combustion can be achieved.

On the other hand, the bypass pipe 28 has its inflow end 2
A part of the combustion gas G flows in from 8a and flows out from the outflow end 28b while receiving high heat in the reburning chamber 20. The decisive difference between the inside of the reburning chamber 20 and the inside of the bypass pipe 28 is that in the former, thermal reactions and other chemical reactions (oxidation, reduction, etc.)
While the latter only undergoes a thermal reaction,
Another chemical reaction is that it is blocked. Therefore, by analyzing the combustion gas from the gas outlet 24 and the outlet end 28b, the extent of the influence of other chemical reactions is specifically clarified.

Through the measurement holes 2 to 10, the temperatures of the reburning chamber 20 and the bypass pipe 28 in the vicinity were measured, respectively. FIG. 2 is a temperature distribution comparison diagram in which both temperatures are plotted with respect to the measurement holes. The circles indicate the body temperature (temperature in the reburning chamber), and the squares indicate the temperature of the bypass pipe. It can be seen that the temperatures of the two are almost the same. From the coincidence of the two temperatures, it becomes more apparent that the difference in the properties of each combustion gas G from the gas outlet 24 and the outlet end 28b is due to the presence or absence of a chemical reaction other than a thermal reaction.

FIG. 3 shows a second embodiment of the present invention, in which a reburning analysis type reburning apparatus according to the present invention is applied for controlling a reburning apparatus provided in a waste incinerator. It is shown. In FIG. 3, reference numeral 33 denotes a reburning controller, reference numerals 33a and 33b denote control lines, and the other members are exactly the same as those in FIGS.

In the second embodiment, the surrounding wall 22 forming the reburning device 16 is disposed in parallel with the outside of the combustion chamber 54b of the waste incinerator. Is open to the lower part of the combustion chamber 54b of the incinerator. Similarly, the lower end of the bypass pipe 28 of the reburning device 16 is also opened to the lower part of the incinerator combustion chamber 54b, and a part of the combustion gas G generated on the stoker 53 is regenerated in the recombustion chamber 20 and the bypass pipe 28. Flows into

On the other hand, the upper openings of the reburning chamber 20 and the bypass pipe 28 are connected to a reburning controller 33, respectively. The components of each combustion gas are individually analyzed. In FIG. 3, reference numeral 26a denotes a fuel injection portion, which is a mixed gas C (a mixed fluid of natural gas N and recirculated gas G _O which is a part of the combustion gas G) from the gas mixer 61.
Is supplied. 26b is a secondary air A blowing section.

In the second embodiment, almost the same reburning state as in the combustion chamber 54b of the waste incinerator is reproduced inside the reburning device 16, and the reburning of the reburning device 16 is performed. From the analysis of the combustion gas in the chamber 20 and the bypass pipe 28, the reburning state in the combustion chamber 54 can be detected without a time delay,
Recirculating gas blower 6 via control lines 33a and 33b
By appropriately adjusting the secondary and secondary air blowers 64 and the like, the operation control of the reburning device of the waste incinerator can be achieved with higher accuracy and higher responsiveness.

FIG. 4 shows a third embodiment of the present invention, in which the reburning analysis type reburning apparatus according to the present invention is applied as it is to a reburning apparatus of a waste incinerator. That is, in the third embodiment, the combustion chamber 54b of the waste incinerator is used as it is as the reburning chamber 20 of the reburning analysis type reburning device 16, and a bypass pipe is provided inside the combustion chamber 54b. 28 are erected. Further, the combustion gas flowing through the inside of the upper portion of the combustion chamber 54 b (reburning chamber 20) and the upper end opening of the bypass pipe 28 is led out and introduced into the reburning controller 33. The recirculation gas blower 62 and the secondary air blower 6 are controlled by a control signal from the reburning controller 33.
The adjustment of 4 and the like is performed in the same manner as in the second embodiment shown in FIG.

In this embodiment, the operation of a reburning device such as a waste incinerator can be controlled more logically and with higher precision than in the case of the conventional reburning device. The utility is achieved.

The present invention is not limited to the above embodiments, but includes various modifications and design changes within the technical scope of the present invention without departing from the technical concept of the present invention. is there.

[0036]

According to the present invention, as described in detail above, the flow of the combustion gas in the reburning chamber is separated into the main flow and the bypass flow,
The configuration is such that the gas itself is maintained such that there is no exchange of the gas itself while maintaining the temperature distribution of both. As a result, the main stream flowing out of the reburning chamber is affected by thermal reactions and other chemical reactions, whereas the bypass stream flowing out of the bypass pipe is only affected by thermal reactions. In other words, since the effects of the thermal reaction and other chemical reactions can be completely separated, precise chemical analysis of the reburning process can be performed for the first time. As a result, the most efficient reburn control can be performed, and a reburn analysis-type reburning apparatus that is extremely useful in industry can be realized.

[Brief description of the drawings]

FIG. 1 is a simplified sectional view showing a first embodiment of the present invention.

FIG. 2 is a comparison diagram of a temperature distribution between a reburning chamber and a bypass pipe in the apparatus of FIG.

FIG. 3 is a simplified vertical sectional view showing a second embodiment of the present invention.

FIG. 4 is a simplified vertical sectional view showing a third embodiment of the present invention.

FIG. 5 is a simplified longitudinal sectional view showing an example of a reburning device provided in a conventional waste incinerator.

[Explanation of symbols]

2 to 10 are measurement holes, 54a is a main combustion chamber, G is a combustion gas,
16 is a reburning device, 18 is a gas inlet, 20 is a reburning chamber, 22 is a surrounding wall, 24 is a gas outlet, 25 is a sampling means, 26 is a reburning generating means, 26a is a fuel injection part, and 26b is air blowing. , 28 is a bypass pipe, 28a is an inflow end, 28b is an outflow end, 30 is a reduction region, 32 is an oxidation region, and 33 is a reburning controller.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Umeo Inoue 1-2-1, Shinhama, Arai-machi, Takasago-shi, Hyogo F-term in Takuma Central Research Laboratory Co., Ltd. (Reference) 3K078 BA02 BA03 BA21 CA02 CA06 CA08 CA11

Claims (8)

[Claims] In a reburning device for reburning combustion gas generated in a main combustion chamber of a combustion device, a gas inlet portion into which the combustion gas flows, a reburn chamber for reburning the flown combustion gas, Means for generating reburning of the combustion gas in the reburning chamber, a gas outlet for discharging the combustion gas from the reburning chamber, and an inflow end near the gas inlet and near the gas outlet. A bypass pipe having an outflow end outside the combustion chamber; the combustion gas flowing in from the gas inlet is divided into two directions in the recombustion chamber and the bypass pipe, and discharged from the gas outlet and the outflow end of the bypass pipe. A reburning analysis type reburning apparatus characterized in that each combustion gas to be analyzed can be compared and analyzed. 2. The reburning analysis type reburning apparatus according to claim 1, wherein the combustion apparatus is a waste incinerator or a boiler. 3. The reburning analysis type reburning apparatus according to claim 1, wherein the reburning chamber is provided separately from the main combustion chamber of the combustion device, and the combustion gas is introduced from the main combustion chamber into the reburning chamber. . 4. A reburning analysis type reburning apparatus according to claim 1, wherein the reburning chamber is a combustion chamber of a waste incinerator. 5. The reburning analysis type reburning apparatus according to claim 1, wherein sampling means for extracting combustion gas is provided at a desired position in the reburning chamber and / or the bypass pipe. 6. The reburning generating means includes a fuel injection section for injecting fuel for reburning into the reburning chamber, and an air blowing section for blowing air into the reburning chamber to promote reburning. 4. The reburning analysis type reburning apparatus according to 1. 7. A fuel injection part is provided near a gas inlet part, an air blowing part is provided at an intermediate position of the reburning chamber, a gas inlet side from the air blowing part is in a reduction region, and a gas outlet is from the air blowing part. The reburning analysis type reburning device according to claim 6, wherein the part side is an oxidation region. 8. The reburning analysis type reburning apparatus according to claim 6, wherein a mixed gas of natural gas and recirculated gas is injected from a fuel injection section.