JPH093462A - Entrained bed gasifier for fuel containing carbon - Google Patents

Abstract

PURPOSE: To facilitate the discharge of a fused ash in an entrained bed coal gasifier. CONSTITUTION: This fuel gasifier is obtained by installing an auxiliary combustion chamber (8) having a small inside diameter under a coal gasifier (2) having the periphery formed of an oven wall (1) and arranging burners (9) for charging coal and an oxidizing agent on the wall surface of the auxiliary combustion chamber (8) and capable of fusing the ash in the coal charged from burners (3) and (9), collecting the fused ash by the furnace wall (1), flowing down the collected ash on the wall surface and discharging the ash downward from an ash discharge port (5). The inside diameter of the auxiliary combustion chamber (8) is small and the heat loss is low. Thereby, the vicinity of the ash discharge port (5) can locally be kept at high temperatures to readily keep the fused ash (4) at high temperatures by heat radiation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to improvement of ash emission in an atmospheric or pressurized jet bed gasifier for gasifying carbon-containing fuel such as coal for electric power industry and other industries.

[0002]

2. Description of the Related Art FIG. 3 is a schematic view showing an example of an ash discharging section of a conventional spouted bed coal gasification furnace.

A burner (3) is installed in a gasification furnace (2) having a furnace wall (1) around it, and coal, char and an oxidizer are charged therein. At this time, the jet from the burner (3) has a circumferential velocity component in the horizontal cross section of the furnace to give a strong swirl. As a result of this turning, the coal and the ash (4) in the char are captured in a molten state on the furnace wall (1) and discharged downward from the ash discharge port (5). At this time, in order to improve the fluidity of the ash, the combustion heat of the coal charged from the burner (3) keeps the ash at a high temperature and lowers its viscosity.

In the gasification furnace, in order to burn and gasify as much coal as possible, it is necessary to secure a sufficient residence time in the furnace for the coal particles and the produced gas. There is a need. As a result, the wall surface area increases and the amount of heat loss increases,
The gas temperature may not be high enough for ash emission.
That is, the molten ash content in the coal and char is captured by the furnace wall (1) by the swirling of the jet flow ejected from the burner (3),
The ash can be separated, but the separation of the input air and the input coal and char occurs and the combustion reaction is hindered. Further, since the separated coal is mainly burned by the centrifugal force in the vicinity of the peripheral wall (1), a temperature high enough to stably discharge ash cannot be obtained in the vicinity of the central slag hole (5).

As a countermeasure against this, conventionally, the following auxiliary means have been adopted. A light oil burner (6) is provided below the ash discharge port (5) to keep the molten ash at a high temperature. Mix flux with coal to reduce ash viscosity. Keep the furnace temperature high by increasing the O ₂ concentration in the oxidizer,
Keep the ash hot.

[0006]

As described above, in order to smoothly discharge ash in the gasification furnace, some conventional auxiliary means were required in the prior art, but it had the following problems. It was That is, when a light oil burner is provided to maintain the ash at a high temperature, the apparatus becomes complicated and a fuel other than coal, which is the main fuel, is used, which is disadvantageous in terms of equipment cost and operating cost. In addition, it is economically disadvantageous because a dedicated facility is required when adding flux to coal and when increasing the O ₂ concentration of the oxidizer.

[0007]

In order to solve the above-mentioned conventional problems, the present inventor has installed a burner for charging carbon-containing fuel and an oxidizer on the wall surface of the furnace and provided a molten ash discharge port at the lower end of the furnace. Vertical bed-type fuel gasification furnace for carbon-containing fuel gas, characterized in that the horizontal cross-sectional area of the lower part of the furnace is smaller than the horizontal cross-sectional area of the upper part of the furnace; In addition to the above, the carbon-containing fuel and the oxidizer charging burner are provided on both the furnace wall of the small horizontal cross-section and the furnace wall of the large horizontal cross-sectional area. It proposes a furnace.

[0008]

According to the present invention, the horizontal cross-sectional area of the lower part of the furnace is smaller than the horizontal cross-sectional area of the upper part of the furnace, so that the heat loss in the lower part of the furnace is small and the molten ash discharge port at the bottom of the furnace is small. The vicinity can be locally kept at a high temperature, and therefore the molten ash can be kept at a high temperature by heat radiation to facilitate its discharge. It is even more effective when the carbon-containing fuel and the burner for introducing the oxidant are provided on both the furnace wall of the small horizontal cross section and the furnace wall of the large horizontal cross section.

On the other hand, since the horizontal cross section of the upper part of the furnace is large,
It is possible to secure a long residence time for the coal particles and the produced gas, and the performance as a large-capacity gasifier is improved.

[0010]

FIG. 1 is a schematic diagram showing an embodiment of the present invention. In this figure, the same parts as those of the conventional one described with reference to FIG. 3 are designated by the same reference numerals to avoid redundancy, and detailed description thereof is omitted.

In this embodiment, a vertical gasification furnace (2) having a furnace wall (1) around the upper combustion chamber (7) and a lower combustion chamber (8) having an inner diameter smaller than that of the upper combustion chamber (7). Configure.
Then, coal and char burner (3) are provided on the side wall of the upper combustion chamber (7). The volume of the upper combustion chamber (7) is determined from the residence time required for the combustion of coal and char. The jet from the burner (3) is given a strong swirl by having a velocity component in the circumferential direction within the horizontal cross section of the furnace. A coal charging burner (9) is installed on the side wall of the lower combustion chamber (8). The coal input burner (9) is given no swirl or a weak swirl.

The coal charging burner (9) in the lower combustion chamber (8) is not swirled or weakly swirled, so that coal particles and charged air are not separated and good combustion is obtained. Further, since the lower combustion chamber (8) has a small inner diameter, wall heat loss is small, and the gas in the lower combustion chamber (8) has a high temperature sufficient for stable discharge of ash.

More specifically, FIG. 2 is a diagram showing the relationship between the amount of heat input per unit cross-sectional area of the combustion chamber and the gas temperature within the combustion chamber, but the amount of input heat per unit cross-sectional area increases. It can be seen that the temperature of the gas in the combustion chamber rises as the temperature rises. In the present embodiment, since the horizontal cross-sectional area of the lower combustion chamber (8) is small as described above, heat loss is small, and the vicinity of the bottom ash discharge port (5) can be locally kept at high temperature. It is possible to keep (4) at a high temperature by heat radiation.

On the other hand, since the volume and horizontal cross-sectional area of the upper combustion chamber (7) are sufficiently large, the required residence time of coal particles and produced gas can be secured to be large.

In this way, combustion of the gasification furnace (2)
While maintaining high gasification performance, the viscosity of molten ash can be kept low without the need for other equipment, and ash can be easily discharged.

[0016]

According to the present invention, the molten ash in the gasification furnace can be maintained at a high temperature and easily discharged without using an auxiliary device that requires equipment costs and operating costs.
Further, not only low ash melting point coal but also high ash melting point coal can be burned exclusively for coal, and applicable coal types are expanded.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention.

FIG. 2 is a diagram showing the relationship between the amount of heat applied to a unit cross-sectional area of the combustion chamber and the gas temperature in the combustion chamber.

FIG. 3 is a schematic view showing an example of an ash discharging mechanism of a conventional spouted bed coal gasification furnace.

[Explanation of symbols]

 (1) Furnace wall (2) Gasification furnace (3) Coal and char burner (4) Molten ash discharged (5) Slag discharge port (slag hole) (6) Light oil burner for auxiliary combustion (7) Upper combustion chamber (8) Lower combustion chamber (9) Coal burner for lower combustion chamber

Claims (2)

[Claims] 1. A vertical jet-bed carbon-containing fuel gasification furnace in which a burner for charging carbon-containing fuel and an oxidizer is attached to a furnace wall surface and a molten ash discharge port is provided at a lower end portion of the furnace. A jet-bed carbon-containing fuel gasification furnace, characterized in that the horizontal cross-sectional area is smaller than the horizontal cross-sectional area at the top of the furnace. 2. The carbon-containing fuel and the oxidizer charging burner are provided on both the furnace wall of the portion having a small horizontal cross-sectional area and the furnace wall of the portion having a large horizontal cross-sectional area.
A spouted bed carbon-containing fuel gasifier.