JPS6017611A - Combustion of solid fuel and device therefor - Google Patents

Abstract

PURPOSE:To enable to efficiently burn in low NOx concentration by a structure wherein swirling flame is formed under the shortage of air in an auxiliary combustion furnace and then the air necessary for completion of combustion in a combustion chamber is supplied from the outside of said flame. CONSTITUTION:An auxiliary combustion furnace 3, on which a first blowing-in port 6 to blow solid fuel 5 accompanied by the primary air having the quantity nearly 20% of theoretical amount of combustion air therein is provided and second blowing-in ports 7, 7', 7''... to blow secondary air therein are arranged tangentially thereto is connected to the burner opening 2 of a combustion chamber 1. In this case, the total amount of both the primary and secondary airs is limited to be 60% or less of theoretical amount of combustion air. Further, the tertiary air necessary for the completion of combustion in the combustion chamber 1 is suppliedfrom a third blowing-in port 10 at the periphery of the aperture opening 9 of the auxiliary combustion furnace 3 toward the combustion chamber 1 in such a form so as to surround the flame generated from the auxiliary combustion furnace 3. The generation of NOx becomes low under the condition that the sum of the amounts of both the primary and the secondary airs is in the order of 50-60% of theoretical amount of combustion air.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of burning solid fuel such as coal and coke, and an apparatus used therefor.

More specifically, the present invention relates to a method and apparatus for burning solid fuels with low volatile components, such as anthracite coal, coke, and the like.

In general, solid fuels with low volatile components such as anthracite coal and coke are mainly composed of free carbon, and have poor ignitability and significantly inferior combustibility compared to gas, liquid fuels, steam coal, etc. It occurs frequently, and it is problematic to apply it alone to conventional combustion equipment such as boilers.

In general, it is well known that the size of the particles and the temperature of the combustion atmosphere or the temperature of the combustion particles are important factors for efficient combustion of solid powders made of free carbon such as 2゜). However, regarding the particle size, industrial
There are economical restrictions on pulverization, and even if ultrafine particles of JOμ or less are formed, the particles will mutually reagglomerate, making it less effective in actual combustion.

Regarding the combustion atmosphere temperature, it is advantageous to form a high-temperature flame and atmosphere, but on the other hand, the generation of nox becomes significant. Regarding ignitability, solid fuels with low volatile components significantly delay ignition. Therefore, normally all fuel with good ignitability, such as heavy oil or gas, is added for combustion.

Further, regarding NOx, the nitrogen content in solid fuel is 10 to 20 times that of heavy oil, and a large amount of twerk NOx is generated. For this purpose, two-stage combustion exhaust gas circulation is implemented. However, these methods lower the combustion temperature and slow the combustion rate. It also produces a large amount of unburned remains.

It is a national precept that these conditions are applied solely to ordinary combustion equipment, such as coke ovens, or pulverized coal boilers for general coal workers. Only a small portion of these combustible fuels are used instead.

This invention was made in view of the situation described below, and its objective r+9 is that the flame-retardant solid fuel described below can be used with thermal coal by simply adding a simple auxiliary combustion device to conventional equipment. The purpose of the present invention is to provide a method that can be used not only as a substitute for heavy oil, but also as a substitute for heavy oil depending on the product with a low ash content, and all the equipment used therein.

First, an outline of this invention will be described: (1) A swirling flame is completely formed in an auxiliary combustion furnace outside the combustion chamber under insufficient air, and this is blown into the combustion chamber. (2) Combustion is completed in the combustion chamber. The air necessary for Nox is used for efficient combustion.

Hereinafter, this invention will be described in detail with reference to examples and a TL mask.

First, T, J shown in Figure 1: To the burner port 2 of the normal combustion chamber 1 of a boiler, etc., to the entire auxiliary combustion furnace 3, ? They can be connected via a connecting pipe 4, or as shown in Figure 2. The auxiliary combustion furnace 3 is lined with refractory material, and is provided with a first inlet 6 through which 5K of pulverized solid fuel with 0σ resistance to twisting is blown in together with primary air within approximately 20% of the theoretical combustion air storm.
In addition, as shown in Figure 8, second blowing lowers 7', 7'', etc., which blow tertiary air in the tangential direction, are suitable for generating a high-speed swirling flow 3 in the auxiliary combustion furnace 3. is set, thereby blowing in secondary air.Then, JO of both the secondary and secondary air is limited to within 60% of the Rikoma combustion air amount.8 is at the initial stage of combustion. 1 for gas or liquid fuel, having an ignition means for raising the temperature inside the furnace 3;
-It is.

Furthermore, in the combustion ζr l thy, the tertiary air necessary for the completion of combustion is supplied around the opening 9 to the fuel regulator 1 of the auxiliary combustion furnace 3 or around the opening 9 of the connecting pipe 4 to the combustion chamber 1. T, l shown in Figure 4, around the auxiliary combustion furnace
The flames of Ka and Ra are completely encircled, and all 10 of the entrances are carved, and they are supplied from the old pipe 10. IJj 'dU! The cross-sectional area of the aperture 9 and the ratio of the three-point injection [F of 10, - the ratio of the white f1j, the unit of tertiary air is 11], and the injection F of the 3D air, and the injection of the IIL to the auxiliary combustion furnace. , -12υ, so that the air has a concentration equal to or higher than the ratio of the solid fuel injection Li.And by using the apparatus and method created in this way, the following characteristic combustion can be achieved. It will be done. Ja
First, the temperature inside the auxiliary crystalline furnace 3 is brought to the same temperature using the dedicated burner 8 using gas '4' fc, and then, when the combustible solid fuel 5 described in FJiJ is fully heated, the flame of the dedicated burner 8 The solid beverage will continue to burn stably even if it is ignited and the combustion starts completely.Even if the dedicated burner 8'ft is then extinguished, the solid beverage will continue to burn stably. Since a high-speed swirling flow is formed by the secondary air in the third circle of the furnace, half of the combustion and half of the gasification progress, and the air is blown into the combustion chamber 1 while forming one swirling flame. In the combustion chamber 1, the swirling flame comes into contact with tertiary air from around the flame to complete combustion, but the residual particles in the flame are distributed around the outer periphery of the flame, so they quickly come into contact with the tertiary air, and furthermore, the particles remain in the flame center. The fuel is backed up by high-temperature radiant heat from the surrounding area and burns rapidly. In addition, the combustible reducing gas such as Go in the flame is combusted at a later stage by mixing with the tertiary air diffusing the flame, but at the same time, it also has the effect of reducing the Nox generated in the flame. Note that the above combustion is
In order to effectively perform the operation with low NOx, the amount of secondary air and the ratio of the supply speed of fuel and tertiary air are adjusted between the second air inlet 10 and the opening to the combustion chamber 1 of the auxiliary combustion furnace 3. In relation to the ratio with the hole opening 9, it is formed as described above◇This means that when looking at the primary air When the air is blown to a high content, the discharge l:Jt of the first blowing port 6 is worn out.

Due to centrifugal force, the inside of the auxiliary combustion furnace is not used effectively and the combustion rate deteriorates, so blow in the axial direction at the lowest possible wind speed. However, if it is too small, it will cause instability in gust transportation, so the amount should be about 20 mlB per blowing air series and within 20% of the theoretical combustion air amount, preferably about 10 to 15%.

In addition, the higher the sum of the total air volume of both primary and secondary air, the higher the temperature inside the auxiliary combustion furnace 3 and the better the combustibility, but if the sum is 60% or more of the theoretical combustion air volume, the temperature inside the furnace If the temperature exceeds 1,500°C, problems may occur due to the heat resistance of the refractory material or the melting of ash. Further, regarding Knox, the amount becomes low when the surface air amount is about 60%.

Moreover, when it exceeds 80%, the flame becomes high temperature and thermal nox occurs, and 7-1-elnox occurs due to a decrease in the two-stage combustion effect due to a decrease in tertiary air. Also 5
If it is less than 0%, the temperature inside the auxiliary combustion furnace 3 decreases, and the generation rate of reducing gases such as CO decreases. Further, the combustion rate on the combustion chamber 1 side increases, so that the Knox increases slightly.

Therefore, the amount of air blown into the auxiliary combustion furnace 3 must be limited to within <60% as shown in nU, using the melting temperature of the ash as a guide. Furthermore, the ratio of the cross-sectional area of the aperture 9 and the cross-sectional area of the air inlet 10 is calculated as follows: What made the ratio higher than the barring amount of solid fuel was to make the mass velocity of each of the swirling flames in the axial direction relatively faster on the tertiary air side. The rapid spread of swirling flame into the combustion chamber is suppressed by tertiary air,
Combustion zone The flame is mainly on the outer periphery, and the fuel particles concentrated on the outer periphery of the flame burn preferentially, and the combustion of internal QCO and other reducing gases continues as the large flame spreads. . The solid fuel, which requires combustion time for this combustion process, is not in a state where it is easy to burn, but because it is a film-like combustion on the flame surface and the combustion of carbon particles precedes it. The radiant power of the flame is high, the heat dissipates quickly to the surrounding area, and the heat transfer efficiency is good.Moreover, the rise in combustion gas temperature is suppressed, and reducing gases such as CO are retained in the post-combustion stage, so the Knox reduction effect is excellent. Therefore, despite efficient combustion, the photogenicity can be suppressed to a low level.

As described above, according to the present invention, solid fuel with low volatile content, which has not been used in conventional combustion equipment such as boilers, can be used in a simple auxiliary combustion furnace to reduce the amount of waste. It can be burned efficiently with NOX.

[Brief explanation of the drawing]

Figure 1 shows an embodiment of the present invention, and is a diagram showing an outline of a solid fuel combustion method and an apparatus used therein. Figure 2 shows a second embodiment of the invention. 1' 1 [Sono's m-m line arrow view, Iku 4 is a cutaway view of IV-[V gland of Iku 1]. l...P-combustion chamber 3...Auxiliary combustion furnace 6...First inlet 7.7', 7''...Second inlet 8...Gas is liquid combustion burner 1)...・1st hole 10...A-3rd hole agent Patent attorney Yugai Saito 2 AIEI] False 3 Figure 7 7 Value 4 Prison procedure amendment Kazuo Wakasugi, Commissioner of the Japan Patent Office 1, Indication of the case Showa Kaku Year Special Application No. 126391 2. Name of the invention Method for burning solid fuel and its use Table 3. Person making the amendment Related to the case Patent applicant address 6276 Onoda, Onoda City, Yamaro Prefecture Name of Kaji (
024) Detailed explanation column for Onoda Cement Hayashi Shiki Company Hikaru Moe , :, ) (1) 1 H1lJJ νI 7 pages 2 and 9 Ite 8 pages 18i 9 Oni 14 Ite 2 and 10 Oni lines "Co" in each case is corrected to rcOJ. (2) On the same page 0, 3y, in line 7, correct the word ``simple'' to ``simple.''

Claims (1)

[Scope of Claims] l Solid fuel is blown into an auxiliary combustion furnace and combusted together with primary air that is approximately solid % or less of its theoretical combustion air amount, and secondary air is tangentially blown into the auxiliary combustion furnace, The amount of air blown into both the primary and secondary air is set to approximately 60% or less of the theoretical combustion air amount of the solid fuel, and the fuel undergoing swirl combustion in the auxiliary combustion furnace enters the combustion chamber in a swirling state. A method for burning solid fuel, which comprises introducing tertiary air necessary for completing combustion of the fuel from outside or from the side of the fuel during swirl combustion. 2 The opening of the auxiliary combustion furnace (3) lined with personnel-resistant material (
9) is communicated with the combustion chamber (1), and the auxiliary combustion furnace (08) is connected to the combustion chamber (1).
3) is provided with a gas or liquid combustion burner (8) and a first inlet (6) that supplies solid fuel together with primary air, and a second inlet (7J) that supplies secondary air tangentially. ,
(7, (7')... are installed, and a P7iJe combustion chamber (
1) - A second inlet (10) is provided to supply tertiary air. 10) The ratio of the cross-sectional area is the amount of secondary air blown per unit time,
A solid fuel combustion method according to claim 1, characterized in that the ratio of the amount of secondary air and solid fuel blown into the auxiliary combustion furnace per unit time is -1 or more. .