CN102269515B

CN102269515B - Melting furnace

Info

Publication number: CN102269515B
Application number: CN201110161499.0A
Authority: CN
Inventors: 河本祐作
Original assignee: Chugai Ro Co Ltd
Current assignee: Chugai Ro Co Ltd
Priority date: 2010-06-04
Filing date: 2011-06-02
Publication date: 2014-01-08
Anticipated expiration: 2031-06-02
Also published as: JP2011257014A; KR101269794B1; CN102269515A; JP5203421B2; KR20110133414A; TWI429872B; TW201207345A

Abstract

The invention provides a melting furnace, which has the advantages of energy saving, low NOx and simple structure. The melting furnace (1) comprises a furnace body (2). Melting material (As) is accommodated inside the furnace body (2). A burner (3) is provided for providing a concentrated flame to the melting material. An auxiliary air nozzle (4) is provided for providing auxiliary flame air to the furnace body (2). The auxiliary flame air is used for the self combustion of the residual fuel in the flame gas burned by the burner (3). A control unit (10) is provided for reducing the flow of the main flame air and increasing the flow of the auxiliary combustion air.

Description

Melting furnace

Technical field

The present invention relates to melting furnace.

Background technology

From the angle of environmental protection, also require the low NOxization of waste gas for the melting furnace of the waste material (being melted material) of melting aluminum or copper etc.For example in patent documentation 1, put down in writing a kind of melting furnace, this melting furnace is provided with position from separating and makes the burner of its smoulder (diffusion combustion) to feed fuels in stove and air, thereby has reduced NOx.Also put down in writing the technical scheme of using heat-storage type burner (Regenerative Burner) in melting furnace in patent documentation 1, the described heat-storage type burner running of burning as described below: a pair of burner alternate-running that makes to have heat storage, discharge burnt gas and utilize heat storage to carry out recuperation of heat from burnt gas via unburned burner, utilizing the heat storage preheated burning air that has carried out recuperation of heat.

But for example record in non-patent literature 1, in melting furnace, carry out transferring heat efficiently by making flame impingement be melted material, can improve burn-off rate.Therefore, from energy-conservation angle, think for melting furnace, preferably by fuel and air are mixed, supplies with and make its concentrated combustion to form the burner that is melted the concentrated flame that the directive property of material is high with the kinetic energy impact.

In addition, as record in patent documentation 2, in the situation that use the burner of diffusion combustion mode in melting furnace, also there are the following problems: the material that is melted of low temperature is deposited in the place ahead of burner at start of run, therefore unburned fuel contacts and imperfect combustion occurs with the material that is melted of low temperature, produces cigarette ash.Therefore, proposed a kind of melting furnace in patent documentation 2, this melting furnace is provided with the main burner that carries out diffusion combustion and forms the auxiliary burner that impacts the concentrated flame that is melted material.If a plurality of burners are set like this, structure becomes complicated, and the price of melting furnace raises.

Patent documentation 1: Japanese patent laid-open 8-94253 communique

Patent documentation 2: Japanese patent laid-open 11-325734 communique

Non-patent literature 1: upper wife learn and, " using the present situation of energy-saving of the aluminium melting furnace of heat-storage type burner ", AL, light metal communication AL society of Co., Ltd., in July, 2009 number, 17-20 page

Summary of the invention

In view of the above problems, problem of the present invention is to provide the melting furnace simple in structure of a kind of energy-conservation and low NOx.

For addressing the above problem, melting furnace of the present invention comprises: body of heater, and this body of heater is taken in and is melted material; Burner, this burner can impact the described concentrated flame that is melted material by fuel and main combustion air mixed combustion be formed, and can reduce the flow of described main combustion air and only make the part burning of described fuel; The auxiliary air nozzle, this auxiliary air nozzle is supplied with the auxiliary combustion air in described body of heater, and this auxiliary combustion air is for the remaining fuel spontaneous combustion of burning gases after making to be burnt by described burner; Control module, this control module is melted the rear flow that reduces the described main combustion air of described burner of material fusing described, and increases the flow of the described auxiliary combustion air of described auxiliary air nozzle.

Utilize this structure, the concentrated flame that can make burner is transferring heat efficiently with being melted that material directly contacts, thereby promotes to be melted the fusing of material, until be melted the material fusing.In addition, after being melted the material fusing, by reducing main combustion air, make to concentrate some fuel in flame to burn, make fuel residual in fuel gas under the effect of the air of being supplied with by the auxiliary air nozzle in stove diffusion combustion dispersedly everywhere, thereby radiation heating is carried out on the whole surface that can melt to being melted material the liquation formed, promotes the rising of melt temperature.In addition, by making the fuel diffusion combustion, also can suppress the generation of NOx.

In addition, in melting furnace of the present invention, if make the described flow that is melted the described main combustion air after material fusing in coefficient of excess air below 0.2, can suppress fully the generation of NOx.

In addition, in melting furnace of the present invention, if the total flow of described main combustion air and described auxiliary combustion air is brought down below described degree before being melted the material fusing with respect to the coefficient of excess air of the theoretical air requirement of the fuel flow rate of described burner after being melted the material fusing described, can prevent the imperfect combustion of the concentrated flame of start of run, reduce the NOx of the diffusion combustion for liquation is heated up.

In addition, in melting furnace of the present invention, the unfused material that is melted can block concentrated flame, so flame radiation heat can't arrive its part behind, temperature reduction.Therefore, the described molten state that is melted material can detect according to the Temperature Distribution in stove.

In addition, in the melting furnace of the present invention that can change in the formation position of the state of flame and flame, if in stove the set temperature sensor, can cause because of the impact of flame radiation heat the error that detects temperature to increase.Therefore, can detect the temperature of waste gas in the flue that is not subject to Fire Radiation, thereby as the index of temperature in stove.And, because in stove, temperature raises along with the carrying out of the fusing that is melted material, so can infer the molten state that is melted material according to the EGT in flue.

As mentioned above, utilize the present invention, by 1 burner, just both can make to concentrate flame impingement to be melted material and come efficiently, by its fusing, can to utilize again diffusion flame to come efficiently all melt high-efficiencies ground to be carried out to radiation heating.By this, but melting furnace fuel saving of the present invention consumption realizes energy-saving, and can maintain low-level by the NOx concentration in waste gas.

The accompanying drawing explanation

Fig. 1 is the structure chart of the melting furnace of embodiments of the present invention 1.

Fig. 2 means the figure of the indivedual air mass flows in the melting furnace of Fig. 1.

Fig. 3 means the figure of the overall air mass flow in the melting furnace of Fig. 1.

Fig. 4 is the structure chart of the melting furnace of embodiments of the present invention 2.

Fig. 5 means the figure of the air mass flow in the melting furnace of Fig. 4.

Fig. 6 is the structure chart of the melting furnace of embodiments of the present invention 3.

The explanation of symbol

1,1a, 1b ... melting furnace

2 ... body of heater

3 ... burner

4 ... the auxiliary air nozzle

5 ... flue

7 ... air supply fan

8 ... the whole valve of homophony

9 ... the auxiliary valve of adjusting

10 ... control device

11 ... temperature sensor

12 ... heat storage

18 ... temperature sensor

The specific embodiment

Below, with reference to accompanying drawing, embodiments of the present invention are described.At first, Figure 1 shows that the structure of the melting furnace 1 of embodiments of the present invention 1.Melting furnace 1 comprises: body of heater 2, the mode that this body of heater 2 can be piled up with the mountain shape as shown in double dot dash line is taken in and is melted material (aluminium waste) A _s, and can as shown in solid line, store the liquation A formed by being melted the material fusing _m; Burner 3, this burner 3 will burn (for example LNG) and air (main combustion air) mixes and to body of heater 2 internal spray, make its burning and form concentrated flame; Auxiliary air nozzle 4, this auxiliary air nozzle 4 can be from importing the auxiliary combustion air to body of heater 2 inside near burner 3.

Burning gases in body of heater 2 are discharged via recuperator (recuperator) 6 from flue 5.Recuperator 6 is at this waste gas and be supplied between the auxiliary combustion air of auxiliary air nozzle 4 and carry out heat exchange, thereby carries out recuperation of heat.Main combustion air and auxiliary combustion air are supplied with by air supply fan 7.The flow of main combustion air is regulated by the whole valve 8 of homophony, and the flow of auxiliary combustion air is regulated by the auxiliary valve 9 of adjusting.The whole valve 8 of homophony and the auxiliary aperture of adjusting valve 9 are regulated according to the EGT detected by the temperature sensor 11 of being located at flue 5 by the control device (control module) 10 consisted of computer.

In Fig. 2 with the ratio of the theoretical air requirement of the fuel with respect to being supplied to burner 3, be that coefficient of excess air shows main combustion air in melting furnace 1 and the flow of auxiliary combustion air.In melting furnace 1, the fuel of the maximum combustion amount of supplied burner 3, until EGT reaches for example 1200 ℃, then maintain EGT 1200 ℃ by regulate fuel flow.Then, melting furnace 1 is proceeded the burning running in the situation that EGT is maintained to 1200 ℃, until the temperature of liquation reaches set point of temperature.

As shown in the figure, in melting furnace 1, do not supply with the auxiliary combustion air, the main combustion air that is 1.2 to burner 3 air supply coefficient of excess, make burner 3 completing combustions, until EGT reaches 500 ℃.Now, the fuel of supply is all in the internal-combustion of concentrating flame.The rectilinear propagation of burner 3 formed concentrated flames, be that directive property is good, impact the materials A that is melted that the mountain shape piles up _s, utilize its kinetic energy that heat is passed to efficiently and is melted materials A _s.

The fusion temperature of aluminium is 660 ℃, therefore can think if EGT reaches 500 ℃, directly is exposed to the materials A that is melted of concentrating flame _sreach higher temperature, at least a portion fusing, become liquation A _m.Therefore, in melting furnace 1, if EGT reaches more than 500 ℃, can reduce the flow of the main combustion air of burner 3, and from auxiliary air nozzle 4 by the auxiliary combustion air supply to body of heater 2 inside.

By reducing the flow of main combustion air, in the concentrated flame of burner 3, a part of fuel unburned is and residual, and the burning gases that comprise unburned fuel diffuse in body of heater 2.These burning gases have the above temperature of ignition point of fuel, thus in unburned fuel and auxiliary combustion air by 4 supplies of auxiliary air nozzle contained oxygen meet will spontaneous combustion.That is, a part that is supplied to the fuel of burner 3 breaks away from from concentrated flame, diffuses to the inner also burning simultaneously of body of heater 2, forms throughout diffusion flame.

This diffusion flame also is formed on the part of concentrating flame to arrive, by radiant heat to the solid-state materials A that is melted _swith liquation A _mheating.If be melted materials A _sfusing carry out, liquation A _mincrease, with utilize to concentrate flame to carry out local heat to compare, utilize diffusion flame to carry out the method transferring heat more efficiently of the radiation heating of globality.Therefore, in melting furnace 1, as shown in Figure 2, along with the rising of EGT, reduce gradually the flow of main combustion air, increase gradually the flow of auxiliary combustion air simultaneously.

In melting furnace 1, if EGT reaches 800 ℃, can think and be melted materials A _sroughly all be fused into liquation A _m.Therefore, in melting furnace 1, when EGT reaches 800 ℃, the coefficient of excess air of main combustion air is set as to 0.1, the coefficient of excess air of auxiliary combustion air is set as to 1.0.Here, as shown in Figure 3, the overall coefficient of excess air of main combustion air and auxiliary combustion air is labeled as to 1.1.This is because in melting furnace 1, and owing to making fuel diffusion smoulder when the high temperature, the formation during therefore with low temperature concentrates the situation of flame to compare, even also can make the burning of fuel noresidue ground with lower coefficient of excess air.

In melting furnace 1, by reducing as mentioned above coefficient of excess air, can suppress the generation of NOx.For obtaining the effect that reduces NOx, be better that the coefficient of excess air of main combustion air is made as below 0.2.Although can further reduce the coefficient of excess air of main combustion air, owing to will keeping the just concentrated flame of needs reservation of flame, therefore the coefficient of excess air of main combustion air at least needs to guarantee in 0.01 left and right.

In addition, although the temperature of the burning gases of the temperature of the waste gas in flue 5 and body of heater 2 inside is roughly the same, if but temperature sensor 11 were located to body of heater 2 inside, temperature sensor 11 self would directly be heated by flame radiation heat, thereby can detect the temperature higher than the temperature of burning gases.In melting furnace 1, because the formation position of the state of flame and flame can change, so the detection error caused by the flame radiation thermal conductance is non-constant, is difficult to rule of thumb proofread and correct and detects temperature.Therefore, in melting furnace 1, temperature sensor 11 is located to the flue 5 of the impact that does not have flame radiation.

Then, Figure 4 shows that the structure of the melting furnace 1a of embodiments of the present invention 2.Below, in the explanation, the inscape identical to the embodiment with above explanation is marked with identical symbol, omits repeat specification.Melting furnace 1a comprises 2 paired burners 3 and comprises 2 paired auxiliary air nozzles 4.Auxiliary air nozzle 4 has respectively heat storage 12, can supply with the auxiliary combustion air via heat storage 12.

By the whole valve 8 of homophony, come the main combustion air of adjust flux only to be supplied to the burner 3 of a side of being selected by main supply valve 13, only have the running of burning of a burner 3.In addition, by the auxiliary valve 9 of adjusting, come the auxiliary combustion air of adjust flux to be supplied to body of heater 2 inside by auxiliary air nozzle 4, this auxiliary air nozzle 4 is the auxiliary air nozzles by auxiliary supply valve 14 burner 3 homonymies with being burnt that select.

In addition, auxiliary air nozzle 4 is adjusted valve 16 and is connected with the exhaust flow path of exhaust fan 17 with comprising exhaust via air bleeding valve 15, also the burning gases in body of heater 2 can be discharged via heat storage 12.

; in melting furnace 1a; when carrying out diffusion combustion; supply with the auxiliary combustion air for one in auxiliary air nozzle 4; via the burning gases in another auxiliary air nozzle 4 discharge bodies of heater 2; by making their alternate-runnings, can obtaining, utilize heat storage 12 to carry out from waste gas the effect that recuperation of heat carrys out the so-called heat-storage type burner of preheating auxiliary combustion air.

In addition, in melting furnace 1a, balance for the heating and cooling that keep heat storage 12, regulate exhaust and adjust the aperture of valve 16, make the burning gases of approximately 20% the amount of the total amount that is equivalent to the main combustion air supplied with to body of heater 2 via burner 3 and the auxiliary combustion air of supplying with to body of heater 2 via auxiliary air nozzle 4 discharge via flue 5.

Figure 5 shows that main combustion air in the melting furnace 1a of present embodiment and the flow of auxiliary combustion air.In present embodiment, when the EGT in flue 5 is low, the coefficient of excess air of the main combustion air of burner 3 is controlled to 0.5, import by auxiliary air nozzle 4 the auxiliary combustion air that coefficient of excess air are 0.7.In addition, in present embodiment, be not that the flow of main combustion air and auxiliary combustion air is gradually changed, but reach 800 ℃ at EGT, think, when being melted material all melts, the coefficient of excess air of main combustion air is become to 0.1, the coefficient of excess air of auxiliary combustion air is become to 1.0, change the ratio of concentrated combustion and diffusion combustion in discontinuous mode.

In addition, in the melting furnace 1a of present embodiment, suppose and will arrive the liquation A of set point of temperature _msupply with and be melted materials A immediately after discharge _s, at body of heater 2, reach under the state of high temperature of certain degree start to carry out on once burning running.But, after the phase that shuts down finishes during just entry into service etc. EGT lower than in the situation of 300 ℃, also the coefficient of excess air of main combustion air can be made as to 1.2, do not import the auxiliary combustion air, only by concentrated combustion, carry out entry into service.

Certainly, as shown in Figure 2, in the melting furnace 1a formed at the device of the present embodiment with heat storage 12, also can reduce accordingly main combustion air with the rising of EGT and increase the auxiliary combustion air, thereby make to concentrate the ratio of flame and diffusion flame to change continuously.

In addition, Figure 6 shows that the melting furnace 1b of embodiments of the present invention 3.In present embodiment, form direction at the top of body of heater 2 along the flame of burner 3 and dispose a plurality of temperature sensors 18.As mentioned above, each temperature sensor 18 that is exposed to body of heater 2 inside not only detects the temperature of the burning gases of body of heater 2 inside, also detects the formed flame radiation heat of burner 3.

As shown in the figure, there is the solid-state materials A that is melted _ssituation under, the formed concentrated flame of burner 3 is because being melted materials A _sand be blocked halfway.Therefore, the temperature sensor 18 of only being located at the position of the burner 3 in turning round near burning can detect concentrates flame radiation heat, detects than the higher temperature of temperature sensor 18 of a side of the burner 3 away from the burning running.That is, can think detect temperature sensor 18 that temperature is higher under be melted materials A _smelt.

If be melted materials A _sall be fused into liquation A _m, concentrate flame to run through body of heater 2 inside, all temperature sensors detect all roughly the samely concentrates flame radiation heat.Therefore, in melting furnace 1b, the difference that detects temperature of temperature sensor 18 reaches certain set point of temperature when following, is judged as and is melted materials A _sbe fused into liquation A _mthereby, reduce the flow of main combustion air, increase the flow of auxiliary combustion air, reduce to concentrate flame, make the residual fuel diffusion combustion.

In the present invention, except the method for above-mentioned embodiment, for example also can be provided for taking the video camera of body of heater 2 inside, process to judge by image to be melted materials A _sthe fusing degree.

Should be understood that in addition the terms such as main combustion air in the present invention, auxiliary combustion air refer to the gas of supplying with the required oxygen of burning, all be comprised in above-mentioned term as any gas in oxygen supply source.

Claims

1. a melting furnace, is characterized in that, comprising:

Body of heater, this body of heater is taken in and is melted material;

Burner, this burner can impact the described concentrated flame that is melted material by fuel and main combustion air mixed combustion be formed, and can reduce the flow of described main combustion air and only make the part burning of described fuel;

The auxiliary air nozzle, this auxiliary air nozzle is supplied with the auxiliary combustion air in described body of heater, and this auxiliary combustion air is for the remaining fuel spontaneous combustion of burning gases after making to be burnt by described burner;

Control module: described be melted material fusing before, form described concentrated flame in described burner, directly heat the described material that is melted; Described be melted material fusing after, the flow of the described main combustion air by reducing described burner, and increase the flow of the described auxiliary combustion air of described auxiliary air nozzle, form diffusion flame, by the described material that is melted of radiant heat heating of described diffusion flame.

2. melting furnace as claimed in claim 1, is characterized in that, the described flow that is melted the described main combustion air after material fusing in coefficient of excess air below 0.2.

3. melting furnace as claimed in claim 1 or 2, it is characterized in that, the total flow of described main combustion air and described auxiliary combustion air is brought down below described degree before being melted the material fusing with respect to the coefficient of excess air of the theoretical air requirement of the fuel flow rate of described burner after being melted the material fusing described.

4. melting furnace as claimed in claim 1 or 2, is characterized in that, described control module detects the described molten state that is melted material according to the Temperature Distribution in stove.

5. melting furnace as claimed in claim 1 or 2, is characterized in that, described control module is inferred the described molten state that is melted material according to the EGT in flue.