JPS6034007B2 - High load combustion method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a method for directly feeding high viscosity substances and solids having a natural property, which are difficult to feed into a combustion furnace and combusting them, and substances with a low calorific value without a natural property to the combustion furnace. and how to burn it efficiently.

2. Description of the Related Art It is conventionally known to tangentially introduce combustion air into a combustion furnace to form a swirling flow, and to carry out mist fluid such as waste liquid on this swirling airflow for incineration. In addition, as a method for treating incompletely combusted gas containing a relatively small amount of combustible solid particles such as soot, the incompletely combusted gas is introduced from the bottom of an upright cylindrical furnace with no bottom, and then One that incinerates by raising the swirling and descending high-temperature gas film caused by a specific nozzle (Hakamakai Publication No. 53-30043), and one that sends combustion air toward the supply port of the material to be combusted. Rotary kiln type incinerator (Mochiseki Sho 4)
No. 8-83667), a waste oil combustion furnace (Jiko Sho 52-49680), which also has a slanted hearth, or coal, which is a fuel that can be pulverized, is turned into a swirling airflow in a state close to mist. Horizontal furnaces such as cyclone furnaces, which burn on top of each other, are also known. However, hard pitch and plastics, which are solid at room temperature but are difficult to pulverize and become melted and sticky or highly viscous with slight heating, have extremely high viscosity themselves or are altered by heating. Materials that are viscous or difficult to fluidize, such as clay oil, asphalt, soft pitch, and residual oil, which are difficult to put into a combustion furnace, and waste materials that are pulverizable but have poor combustibility. Activated carbon, so-called char generated in coal gasification or liquefaction processes, less natural waste liquids, waste sludge, and radioactive granular or powdered waste ion exchange generated in nuclear power plants, etc. It is extremely difficult to burn resins, etc. under high load using the conventionally known furnaces and methods as described above, and a large amount of unburnt material may accompany the combustion gas, or carbide may be present in the furnace or in the furnace. Since the fuel falls and accumulates at the bottom of the tank, there is a problem in that it is difficult not only to achieve complete combustion, but also to continue the combustion itself.

As a result of intensive research to solve these problems, the inventors of the present application have developed a horizontal furnace that is capable of bed combustion when unburned materials fall, and developed The present invention was completed by discovering that the position, direction, blowing speed, etc. are extremely important factors for the complete combustion of the above-mentioned flame retardant substances.

That is, in the present invention, objects to be burned are fed by flowing down or falling through a nozzle or the like to the front part of a horizontal incinerator having a U-shaped or trapezoidal end, and combustion air is directed toward this feed part to combust. By feeding at high speed in a direction tangential to the inner wall of the furnace and preferably at a specific angle in the upstream direction, the object to be burned is suppressed at the front of the combustion chamber, and at the same time a powerful swirling flame is generated. The present invention was achieved by discovering that there is an effect of suppressing the front part of the combustion chamber.

The present invention utilizes this effect (hereinafter referred to as flamehold vortex flow) to produce high-viscosity liquids, combustible substances and slurry substances that are solid at room temperature but turn into high-viscosity liquids at room temperature, and auxiliary fuels that do not have natural properties. It is possible to achieve high-load combustion by using waste liquid and waste sludge that can be produced in barrels, as well as flammable but difficult to incinerate substances (hereinafter referred to as fuel) that can be fed in solid form by crushing, to achieve high-load combustion. This method significantly increases the combustion load compared to conventional methods. The above fuels include various oil-based sludges, pitch, asphalt, vacuum distillation residue, extraction residue, other car oils, COM (mixture of coal powder and oil), polyolefins and other synthetic polymer substances, and various organic synthesis processes. Examples of distillation residues, waste liquids and solids containing organic matter include waste powdered activated carbon, powdered charcoal, etc. In the present invention, an auxiliary burner is provided as necessary to use auxiliary fuel, but this is for preheating the furnace for natural fuels, and is used for low calorific value waste liquids and waste sludge that do not have natural properties. It is used as an ignition source or to maintain furnace temperature.

The present invention will be explained below based on the drawings.

Figure 1 shows a combustion furnace for burning fuel that generates combustion residues such as ash and metals, and Figure 2 shows A-A in Figure 1.
FIG. When the fuel has natural properties, in FIGS. 1 and 2, the auxiliary burner 6 uses the auxiliary fuel 7 such as LPG or heavy oil to heat the combustion furnace 1 to the natural temperature of the fuel (110
Preheat to 0-2000℃) or higher. When the combustion chamber thermometer 8 indicates a predetermined temperature, air is ejected from the combustion air nozzle 3. The fuel is caused to flow down or fall from the fuel feed nozzle 2 near the reactor in the upstream side of the furnace. 1st
In the figure, two fuel feed nozzles 2, 2 are shown, but in reality, only one of these fuel feed nozzles 2, 2' is sufficient.
Depending on the target fuel, it may be fed, for example, from a position such as 2' on the upstream side of the upper part of the cylindrical furnace wall, and the feed is determined in advance depending on the properties of the fuel. Generally, liquids are fed through the fuel feed nozzle 2, and solids and powders are fed falling through the fuel feed nozzle 2'. In addition, in the case of high viscosity liquids, the feed method uses combustion exhaust gas, steam,
Alternatively, it is preferable to heat and melt the material with a suitable heat medium and then feed it with a pump, but it is also possible to feed it by applying pressure using an acid dog method. At this time, if necessary, heat the nozzle up to the tip using hot soot or the like to keep it warm. Further, it is preferable to feed solids and powder using a quantitative table feeder or screw feeder.
Now, as mentioned above, when the furnace temperature reaches a predetermined value using the auxiliary burner, the amount of air suitable for the purpose is introduced from the combustion air nozzle 3, and at the same time, fuel is supplied to ignite and achieve stable combustion. Turn off the auxiliary burner. Needless to say, if the fuel is not natural, the auxiliary burner will continue to be used.
The tangential flow velocity of the combustion air is approximately 60-120/sec.
If the flow rate is less than 40 m/sec, the effect is small, and if it is more than 120 m/sec, it is not practical due to noise and damage to the furnace wall. In addition, in order to distribute the necessary amount of air uniformly according to the size of the combustion furnace and the amount of fuel fed, the combustion air nozzle 3 is not only provided with one, but also with a number of 10 or more as required. Good too. The combustion air nozzle 3 is installed downstream of the fuel supply port, either on a straight line in the horizontal direction of the furnace inner wall, on the circumference of the cross section of the cylindrical furnace 1, or at any arbitrary position, either alone or both. It is possible to provide a composite combination of the following. The angle between the streamline of the combustion air and the generatrix of the cylindrical furnace is preferably in the range of 45 to 75 degrees. Outside this range, it is difficult to maintain the effect of the frame hold vortex flow of the present invention. In addition, the combustion air that enters obliquely tangentially and upstream with respect to the inner wall of the furnace should be kept away from directly hitting the fuel to prevent the fuel fed into the furnace from flowing downstream as much as possible. It is desirable that at least one of the streamlines of the swirling flow passes immediately before or directly above the falling point of the combustible material within two revolutions inside the furnace. When rotating more than 2 times, the wind force weakens somewhat and the effect is diminished.

The amount of combustion air can be adjusted by using valves, dampers, or other appropriate methods (not shown). Combustion gas is extracted from the duct 4 in the tangential direction in the same direction as the frame-hold vortex flow, and is led to a device that requires hot gas, such as a boiler or dryer, and is used as appropriate. It is important to extract the combustion gas leaving the combustion furnace 1 in the same tangential direction as the flame hold vortex flow in order not to disturb the flame hold portex flow. The combustion residue is discharged from the combustion residue discharge port 5. The combustion residue is taken out in the form of a molten state or a powder, depending on the type of fuel. FIG. 3 shows a combustion furnace 101 which is particularly suitable for use with highly decomposable and vaporizable fuels that produce no combustion residue.

In this case, a combustion residue discharge port is not required. For materials such as polyolefin that do not contain ash or metal and are highly decomposable and vaporizable, a U-shaped or trapezoidal cone portion 109 is provided at the fuel feed section at the front of the combustion furnace 101 to prevent heat from falling. It makes it easier to hit the target, promotes vaporization, and causes flame-hold vortex combustion. Fuel is supplied through fuel feed nozzle 10
2 and combustion using the initial auxiliary burner 106 is the same as the explanation in FIG. Figure 4 shows L. P. This is a comparative example showing the combustion results of applying the conventional swirl flow method and the frame hold vortex flow method according to the present invention to the burning of distillation residue containing maleic acid and phthalic acid using the combustion furnace 1 shown in FIG. be.

The operating conditions are as follows. Objects next to the barrel Distillation residue maleic acid containing maleic acid and phthalic acid 33% Phthalic acid 53% Na 2.7% SI. 3% QO I0 Calorific value Approximately 330 thigh cal/k9 Cylindrical furnace used Inner diameter 50 mm Length 230 mm Furnace volume 0.45 combustion air/1 tube Combustion air flow rate 80 m/sec Fuel feed amount 20 kg /day auxiliary fuel L. P. G4. In a dish/H combustion temperature
950 to 1000 qo Residual oxygen in combustion gas 8 to 9% Amount of combustion air 32 side/H The angle that the combustion air nozzle 3 makes with the generatrix of the cylindrical furnace is 70 degrees toward the upstream in the method of the present application, An example of the kettle method was 90 degrees.

Also, the ash is poured into the water from the duct 5, which is directed downward from the rear of the furnace. Continuously guide the combustion gas into the Build up and increase COD value over time (Mn) was measured.

In FIG. 4, the vertical axis is the COD value (P.P.M.), the horizontal axis is the operating time, and the straight lines ``■'' and ``■'' indicate the results of the present invention method and the conventional turning method, respectively.

In the method of the present invention, the COD value after 3 hours of operation is 2. sapm
In contrast, with the conventional rotation method, C after the same 3 hours
The OD value showed 120 ppm. This shows that the flame-hold portex method of the present invention achieves more complete combustion than the conventional method. Next, Table 1 shows examples in which various fuels were used according to the method of the present invention. The combustion furnace used in this experiment was 35mm in inner diameter x 100mm in length.
However, the feed amount and other conditions were the same as those of the comparative example. Test M in Table 1 above. 3 shows an example of two-stage combustion.

This car oil contains 0.4wt% nitrogen, and when one stage of oxidation combustion is performed at a ratio of 1.2, NO becomes 450ppm.
However, this test no. 3 dego = 0.6
After reductive combustion was performed in the furnace, oxidative combustion (total do = 1.2) was performed in another furnace of the same type installed in the latter stage, and through this two-stage combustion, it was possible to reduce NO to 150 ppm. Also, the amount of soot generated was determined by Test M. 9/ of 10-20 through 1-5
N was below.

The present invention is also fully applicable to the incineration of easily combustible materials such as waste paper and pieces of wood, or to the high-load combustion method of pulverized coal.

As mentioned above, in the conventional swirl flow method, the combustion load is 150 x 1 ~ 200 x even for relatively easily combustible materials.
101 Kcal/day, whereas the combustion load due to the flamehold vortex flow according to the present invention increases from 500 x 1 to 600 x 1 Kcal/day at maximum, and depending on the type of fuel, the volume of the combustion furnace may be smaller than that of the conventional one. It is possible to reduce the furnace volume to 1/3 to 1/4.

Furthermore, by this combustion method, inexpensive heavy column, waste plastitta, petroleum distillation residue, and COM, which have been difficult to burn due to their low utility value, can be used as fuel.

Furthermore, according to the method of the present application, in an oxidizing atmosphere, the natural lower limit of fuel is 2.5, and from the combustion temperature of 100,000, 1.
It is possible to achieve complete combustion in all ranges, such as combustion temperature 200,000, and reduction combustion of doku 1, generates almost no soot, has low ash COD, and can save construction and operating costs. This is extremely advantageous for preventing industrial pollution. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a combustion furnace for burning fuel in which residual combustion materials such as ash and metals remain, and FIG. 2 shows a sectional view taken along the line AA in FIG. 1.

Fig. 3 shows a combustion furnace for burning fuel with high decomposability and vaporizability without combustion residue, and Fig. 4 shows a combustion furnace using L. as auxiliary fuel. This is a comparative example showing the combustion results between the subordinate swirl flow method and the frame hold vortex flow method according to the present invention when maleic acid cake was lit in the combustion furnace shown in FIG. 1 using P.G. . 1,101... Combustion furnace, 2,2'
, 102...fuel feed nozzle, 3,101...
Combustion air nozzle, 4,104...Duct, 5...Combustion residue discharge port, 6,106...Auxiliary burner, 7,I
Q7... Auxiliary fuel, 8,108... Combustion chamber temperature gauge,
109...Trapezoidal cone part, 10,110...Fireproof,
Insulated Lesoga, 11,111...Viewing window, 13,1
13... Air nozzle for auxiliary fuel.

first wind Good 2 Calm Moat diagram 5 *4・Figure

Claims (1)

[Scope of Claims] 1. Combustible material is supplied to one end of a model cylindrical furnace whose inner wall on the combustible material supply end side of the cylindrical furnace has a U-shaped or trapezoidal cross section, and a powerful flame stream is applied. In order to keep the combustible material in the vicinity of the inner periphery of the combustible material supply port, it is tangential to the inner wall surface of the furnace from the downstream part of the combustible material supply port, and inclined in the upstream direction with respect to the generatrix of the cylindrical furnace. A high-load combustion method characterized by maintaining and promoting high-load combustion by blowing in a stream of high-velocity combustion air that forms a streamline. 2. The high load according to claim 1, in which at least one streamline of the swirling flow of combustion air passes immediately before or directly above the point where the combustible material falls within two revolutions inside the furnace. Combustion method. 3 The flow rate at the combustion air inlet is at least 6
0 m/sec, and the angle between the streamline and the generatrix of the inner surface of the cylindrical furnace is within the range of 45 to 75 degrees. Law.