JP3770726B2 - Gasification ash melting furnace - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gasified ash melting furnace in a gasification incineration facility that introduces a pyrolysis gas generated in a gasification incinerator and rapidly burns it to melt ash accompanying the pyrolysis gas.
[0002]
[Prior art]
Conventional gasification ash melting furnaces such as those that melt ash entrained in fuel gas and exhaust gas, and swirl melting furnaces such as sludge contain unburned material in the furnace chamber 1 from above as shown in FIG. Gas is swirled and blown from the ignition burner 2 and ignited by the ignition burner 2, and is burned and heated by the combustion air blown from the air nozzle 3, and the ash accompanying the combustion gas is heated and melted and deposited and recovered on the furnace wall. The molten slag was discharged from the discharge port 4 formed at the bottom of the furnace chamber 1. In this melting furnace, the combustion gas is swirled and sent downward, collided with the bottom wall 5 and detoured upward, thereby making the residence time in the furnace chamber 1 as long as possible and bringing the molten slag into contact with the furnace wall. It was structured to ensure many opportunities to do.
[0003]
[Problems to be solved by the invention]
However, in the conventional melting furnace, the ash recovery rate is low, usually only 60%, and about 80% at maximum. As a result, the exhaust gas treatment facility that collects ash and fly ash from the exhaust gas downstream of the exhaust gas duct is increased, and the disposal cost of the slag containing the collected harmful substances increases, which increases the operating cost. It was.
[0004]
An object of the present invention is to provide a gasified ash melting furnace capable of solving the above problems and further improving the recovery rate of slag accompanying the exhaust gas.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the present invention includes a combustion chamber that introduces pyrolysis gas generated in a gasification combustion furnace and blows combustion air at high temperature to heat and melt ash accompanying the pyrolysis gas. the entrained slag in the combustion gases to a gas Kahai melting furnace and a slag recovery chamber for capturing recovering, said Nagareoku direction of the combustion gas from the combustion chamber so as to bypass the side A slag recovery chamber is disposed, and a slag guide floor is formed at the bottom of the upstream side of the slag recovery chamber to collect the molten slag that is inclined downward and recovered to form a recovery slag layer, and upstream of the slag guide floor. A discharge port for discharging the molten slag of the recovered slag layer through the discharge weir is formed on the side, and the axis of the slag is recovered between the combustion chamber and the slag recovery chamber with respect to the combustion chamber axis. It is inclined to the chamber downstream It is obtained by forming a throttle portion for ejecting toward the baked gas to the recovery slag layer of the slag guide floor.
[0006]
According to the above configuration, the combustion gas discharged from the combustion chamber to the slag recovery chamber can collide with the recovery slag layer on the slag guide floor at high speed via the throttle, and the molten slag in the exhaust gas can be effectively recovered . The temperature drop of the recovery slag layer can be prevented. Furthermore, the combustion gas injected from the throttle part collides with the recovery slag layer from the direction inclined to the downstream side of the slag recovery chamber, thereby smoothly flowing the bypass flow of the combustion gas and preventing the occurrence of turbulence, and the exhaust port It is possible to prevent the backflow of the combustion gas to the slag and prevent the quality of the slag from deteriorating. And by the centrifugal force of the combustion gas that makes a detour along the slag recovery chamber, the molten slag having a large specific gravity can be effectively brought into contact with the slag guide floor and the bottom wall, so that the molten slag can be recovered more effectively. The rate can be greatly improved.
[0007]
According to the second aspect of the present invention, the axis of the throttle portion having the above-described configuration is inclined in the range of 20 ° to 30 ° downstream of the slag recovery chamber with respect to the combustion chamber axis, and the slag with respect to the axis of the throttle portion. the inclination angle of the guide bed is obtained by a 90 ° + α (0 ° < α ≦ 10 °).
[0008]
According to the above-described configuration, the recovered slag layer of the slag guide floor is guided to the upstream side by inclining the axis of the throttle portion and making the detour direction of the combustion gas after the slag collision slightly larger than 90 °, thereby heating effect Can be increased, and the bypass flow of the combustion gas can flow smoothly.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Here, an embodiment of the gasified ash melting furnace according to the present invention will be described with reference to FIG.
[0010]
This ash melting furnace introduces and burns a pyrolysis gas containing unburned matter, ash, and dust such as char (dry-distilled carbon) generated by burning in an oxygen-deficient state by the gasification incinerator 10. The ash and the like accompanying the pyrolysis gas are heated and melted and collected as molten slag, and the combustion chamber 11 for combusting the pyrolysis gas and the flow direction of the combustion gas from the combustion chamber 11 are sideways. And a slag recovery chamber 12 for collecting slag from the combustion gas.
[0011]
The combustion chamber 11 is formed in a circular cross section having a vertical axis C1, and is connected to the upper side wall eccentrically from the vertical axis C1 to turn the pyrolysis gas around the axis C1, and a temperature rising burner. 14 and air nozzles 15 and 16 for injecting combustion air into the pyrolysis gas and igniting it.
[0012]
The slag recovery chamber 12 is formed with a bottom wall 21 inclined at a predetermined angle θ2 at the upper part on the downstream side, and further with an exhaust gas passage 22 with a heat exchanger facing upward. Further, the upstream side of the bottom wall 21 is configured as a slag guide floor 21a that collects the collected molten slag to form a recovery slag layer MS, and the molten recovered from the upstream end of the slag guide floor 21a through the discharge weir 21b. A discharge port 23 for discharging the slag is provided. By arrange | positioning this discharge port 23 in the high temperature part of an upstream, the collection | recovery slag layer MS on the slag guide floor 21a is heated effectively, and solidification is prevented.
[0013]
Above the slag guide floor 21 a of the bottom wall 21, a throttle section 31 having a circular cross section that throttles the combustion chamber 11 is opened. The throttle portion 31 has a flow passage inner diameter d set in a range of 0.3 to 0.5 times (throttle ratio: 0.07 to 0.2) with respect to the flow passage inner diameter D of the combustion chamber 11. Thus, the combustion gas can be accelerated rapidly to collide with the recovered slag layer MS on the slag guide floor 21a at high speed, and entrained dust having a large specific gravity can enter the recovered slag layer MS at high speed and be effectively captured. . (Although a constricted portion can be seen in a conventional melting furnace, the purpose of this constricted portion is to stir the combustion gas and lengthen the residence time, and the diameter ratio is about 0.7.)
[0014]
Further, the axis C2 of the throttle portion 31 is formed on the downstream side of the slag collection chamber 12 so as to be inclined at θ3 = 20 ° to 30 °, and a bypass angle θ4 = 90 ° formed by the axis C2 and the bottom wall 21. It is set to + α. This α is set in the range of more than 0 and not more than 10 ° (inclination angle θ2 of the slag recovery chamber 12 = 10 ° to 20 °), and thereby the combustion gas flow injected from the throttle portion 31 can be made smooth. It can be sent to the downstream side to promote the solid separation effect by centrifugal force. Here, since the centrifugal force of the combustion gas is proportional to 1 / r ³ , the centrifugal force of the combustion gas increases about 8 to 27 times, and the dust contained in the combustion gas is transferred to the recovered slag layer MS on the surface of the bottom wall 21. It can be captured effectively by colliding. Further, the bypass angle θ4 can prevent the turbulent flow of the combustion gas, and also prevent the backflow of the combustion gas to the discharge port 23 to prevent the deterioration of the slag quality (entrainment of unmelted material).
[0015]
Here, α is in the range of more than 0 ° and less than 10 ° because the flow of combustion gas is not smooth at less than 0 °, and when it exceeds 10 °, the solids due to the centrifugal force of the combustion gas This is because the separation effect is reduced.
[0016]
In the above configuration, the pyrolysis gas swirled and introduced into the combustion chamber 11 from the gas inlet 13 is supplied with combustion air from the plurality of air nozzles 15 and 16 and burned, and the accompanying dust is heated to a high temperature. The ash is melted. The combustion gas is suddenly accelerated by being introduced into the throttle section 31 and is injected toward the slag guide floor 21a. When the combustion gas collides with the recovered slag layer MS on the slag guide floor 21a at a high speed, the entrained slag is effectively captured and further directly collided by the centrifugal force of the combustion gas that is smoothly turned downstream. The unaccompanied slag is also captured by colliding with the slag guide floor 21a, the bottom wall 21 and the side wall, and the slag in the entrained dust of the combustion gas is captured at a high recovery rate of about 90%. Here, the slag recovery rate (slag conversion rate) (%) is represented by [slag discharge amount / (slag discharge amount + fly ash amount)] × 100. Further, the combustion exhaust gas is discharged to the exhaust gas passage 22, and the captured recovered slag layer MS is kept warm while capturing the slag by contact with the combustion gas, and is discharged from the exhaust port 23. At this time, since the combustion gas is smoothly sent to the downstream side, the combustion gas does not flow back to the exhaust port 23, and the quality of the slag is not deteriorated.
[0017]
According to the above embodiment, the combustion gas sent from the combustion chamber 11 to the slag recovery chamber 12 is greatly squeezed and rapidly accelerated by the throttle portion 31, and the recovered slag layer on the slag guide floor 21a of the slag recovery chamber 12 is high-speed. Since it is brought into collision contact with the MS, the slag can enter the recovery slag layer MS and be effectively captured. In addition, since the bypass angle θ4 formed by the axis C2 of the throttle portion and the slag guide floor 21a is set to a slightly larger angle than 90 °, the flow of the combustion gas is smoothly bypassed, and the slag accompanied by the centrifugal force is reduced. It can be brought into contact with the slag guide floor 21a and the bottom wall 21 and captured effectively, and the slag recovery rate can be greatly improved as compared with the conventional case. Further, the bypassed combustion gas does not flow back to the exhaust port 23, and the quality of the slag is not deteriorated. Furthermore, since the discharge port 25 of the slag recovery chamber 12 is formed at the upstream end of the higher temperature slag guide floor 21a, the molten slag MS can be effectively heated to prevent solidification.
[0018]
【The invention's effect】
As described above, according to the first aspect of the present invention, the combustion gas discharged from the combustion chamber to the slag recovery chamber collides with the recovery slag layer on the slag guide floor at a high speed via the constriction portion, and is melted in the exhaust gas. Slag can be effectively recovered and the temperature drop of the recovered slag layer can be prevented. Furthermore, the combustion gas injected from the throttle part collides with the recovery slag layer from the direction inclined to the downstream side of the slag recovery chamber, thereby smoothly flowing the bypass flow of the combustion gas and preventing the occurrence of turbulence, and the exhaust port It is possible to prevent the backflow of the combustion gas to the slag and prevent the quality of the slag from deteriorating. And by the centrifugal force of the combustion gas that makes a detour along the slag recovery chamber, the molten slag having a large specific gravity can be effectively brought into contact with the slag guide floor and the bottom wall, so that the molten slag can be recovered more effectively. The rate can be greatly improved.
[0019]
According to the second aspect of the invention, the recovery slag layer of the slag guide floor is made upstream by inclining the axis of the throttle portion to make the detour direction of the combustion gas after the slag collision a little larger than 90 °. While guiding to increase the heating effect, the bypass flow of the combustion gas can flow smoothly.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an embodiment of a gasified ash melting furnace according to the present invention.
FIG. 2 is a longitudinal sectional view of a conventional gasified ash melting furnace.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Gasification incinerator 11 Combustion chamber 12 Slag collection chamber 13 Gas inlet 14 Temperature rising burners 15 and 16 Air nozzle 21 Bottom wall 21a Slag guide floor 22 Exhaust gas passage 23 Exhaust port 31 Restriction part MS Molten slag layer

Claims (2)

A combustion chamber that introduces the pyrolysis gas generated in the gasification combustion furnace and blows combustion air at a high temperature to heat and melt the ash accompanying the pyrolysis gas and a slag entrained in the combustion gas. A gasified ash melting furnace having a slag recovery chamber for capturing and recovering,
The slag recovery chamber is arranged to bypass the flow direction of the combustion gas from the combustion chamber to the side,
At the bottom of the upstream side of the slag recovery chamber, a slag guide floor is formed that collects the recovered molten slag inclined downward and forms a recovery slag layer, and on the upstream side of the slag guide floor, the recovered slag layer Forming a drainage outlet for discharging the molten slag through the discharge weir,
A throttle between the combustion chamber and the slag recovery chamber whose axis is inclined toward the downstream side of the slag recovery chamber with respect to the combustion chamber axis and injects combustion gas toward the recovery slag layer on the slag guide floor A gasified ash melting furnace characterized by forming a part. With tilting in a range of 20 ° to 30 ° to the slag recovery chamber downstream the axis of the narrowed portion with respect to the combustion chamber axis,
Gas Kahai melting furnace according to claim 1, characterized in that said slag guide angle of inclination of the floor 90 ° + α (0 ° < α ≦ 10 °) with respect to the axis of the narrowed portion.

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