JPS5839466B2 - Slag taps for coal gasification plants and improvements to coal gasification plants incorporating such slag taps - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coal gasification plant, and more particularly, to a coal gasification plant in which coal or other carbonaceous fuel is introduced into the top of a tower gasifier, and where oxygen and steam are introduced through the siding near the fuel bed. The present invention relates to a slag tap outlet member for use in a slagging gasification plant of the type that performs gasification at high temperatures and high pressures.

The residual ash is collected as molten slag and iron in the gasifier hearth, from where it is periodically discharged and dropped through a slag tap outlet or orifice in the hearth into the water contained in the quench chamber (commonly known as slag tapping). ).

Typically, a pool of molten slag and iron is maintained in the hearth by directing hot combustion products from a burner below the slag tap orifice into the tap orifice;
This molten slag and iron tapping can be reduced by stopping or reducing the burner output and venting the pressure in the quench chamber to the atmosphere with an exhaust system to reduce the pressure difference between the quench chamber and the gasifier. is initiated and controlled by causing .

An example of such a slagging gasifier is British Patent No. 977.
．． No. 122, The Gas Council Re-5
earth commun 1cat 1ons)
Nos., GC50 and GC112.

The slag tap member and hearth containment material of such a slagging gasifier
erials) are susceptible to erosion, corrosion and thermal attack by slag and iron.

During slag tapping and slag retention, the slag tap orifice and the confining material in its immediate vicinity are primarily subject to iron attack and thermal attack due to the high temperature and mobility of the slag and iron.

It is known to be difficult to provide a slag tap outlet for such gasifiers that does not deteriorate rapidly due to the high temperature conditions during operation of the gasifier and the presence of iron in the slag, and the present invention One object of the invention is to provide an improved slug tap member for a slugging gasifier that has fewer of these drawbacks.

According to an upper aspect of the invention, a solid cast ingot
an upper tundish having integrally formed metal tubes for circulating cooling liquid through the st mass and through which the slag discharged from the gasifier flows;
) A slag tap member for use in a coal slagging gasifier comprising a solid cast ingot of highly thermally conductive metal having a surface and a central slag discharge orifice, the upper tundish surface being inclined downwardly and inwardly; , and merged with said slag discharge orifice, said cooling tube being capable of retaining its shape without appreciable deformation during casting of the surrounding metal mass, and said tube passing through said casting mass. forming a cooling tube extending from and adjacent to the tundish surface and the orifice passageway surface and spaced from both surfaces at a distance of 6.35 to 38.1 ytm (0.25 to 1.5 inches); A slug tap member is provided in which the ends of the tube project outwardly from the surrounding cast metal mass to provide a coolant inlet and outlet.

The idea of controlling the flow rate of slag from the hearth side through the slag tap orifice and the resistance of the slag tap member itself to erosion depend, among other things, on the thermal conductivity of the materials used, the shape and geometry of the metal mass, the orifice The design of the slug tap depends on critical factors, including the size, length and location of the coolant passages relative to the surface of the slag tap member exposed to thermal attack.

The amount and flow rate of the cooling fluid are also important in the design of the slag tap, since the exposed surfaces of the metal mass in direct contact with the slag and burner gases must be effectively cooled to maintain an acceptable surface temperature, preferably within 50-400°C. This is an important factor.

However, on the other hand, it is important not to remove excessive amounts of heat from the hearth with the slag tap.

Typically, 20 to 30 ft.
)/second is preferred.

Preferably, the slug tap member is made of copper or a copper alloyed metal.

The uppermost surface of the slug tap member (commonly known as the tundish region) is preferably sloped downwardly and inwardly to merge with the peripheral surface of the central orifice, which may be right cylindrical.

The rotating surface of the tundish may have any suitable cross-sectional profile, for example a partial circle or a parabola, but is preferably frustoconical.

Under typical operating conditions of a gasifier where the slag pool temperature is on the order of 1450°C and the burner gas temperature is about 1500-1600°C, the uppermost surface or tundish of the slag tap member has a temperature of 200-400°C. The cylindrical surface of the orifice is kept at a temperature within a range of 100
The temperature is maintained within the range of ~400<0>C, and the lowermost surface of the slug tap adjacent to the burner is maintained at a temperature within the range of <RTIgt;50-400<0>C.

For convenience, the manufacture of slag tap members for liquid-cooled operation of coal slagging gasifiers of the type described above consists of forming a metal tube into a coil with an inlet and an outlet, around which copper or copper-alloyed metal is formed. and casting the mass into the desired shape such that the inlet and outlet communicate with the outside of said cast mass.

The tube can be made of nickel-chromium or a metal alloyed with nickel-chromium, which is also highly corrosion resistant.

In addition, the outer surface of the tube is coated with the stress of the cast metal during cooling after casting, in order to improve thermal contact with the cast metal, and especially when different metals are used for the tube and the cast metal. Measures can be taken to improve the bond with the cast metal to reduce the tendency for failure.

According to other aspects of the invention, there is provided a gasifier, an apparatus for introducing coal into the gasifier for gasifying the coal in the gasifier, and a device for gasifying coal in the gasifier. a device for introducing oxygen and steam into the gasifier; a hearth located at the bottom of the gasifier and including a slag discharge orifice for discharging slag from the gasifier; a hearth located below the slag discharge orifice; a burner means for directing a stream of hot combustion products to a slag discharge orifice to maintain the slag in a molten state above the hearth; A coal slacking gasifier comprising a quench chamber for receiving and removing slag, and a device for reducing or stopping said hot combustion gas flow to discharge slag from said slag discharge orifice, said slag discharge orifice being located in said hearth. A coal slagging gasifier is provided which is central and shaped as a substantially vertical passageway through a removable slag tap member according to a first aspect of the invention.

Embodiments of each aspect of the present invention will be described below with reference to the accompanying drawings.

First, FIG. 1 will be explained.

The gasifier includes a pressurized gasification chamber 10 lined with refractory material, into which coal is fed from a lock hopper 12 and distributed by a rotary distributor 14.

Oxygen and steam are introduced into the fuel bed (not shown) through the siding 16 to promote gasification of the coal.

During operation of the gasifier, a reservoir or pool of molten slag and iron collects on the inclined hearth 18 and is periodically drained from an orifice made in a removable slag tap member 20 supported within the hearth. After being passed into the water reservoir 22 contained in the quenching chamber 24 where it is quenched in the region of turbulent water supplied by the perforated tubular ring 26, it is accompanied by a small amount of quenching water by the operation of the valve 30. The frit is sent to the lock hopper 28 in the form of a high-density, small-grain frit.

The frit is discharged from the lock hopper 28 onto a moving conveyor 32.

Sudden from entrance 34? A portion of the water supplied to the IJ song 6 is supplied from the quench chamber 24 and the outlet 36, 38 of the slaglock hopper 28 using a pump and a swarf device (not shown).
Water that has been recirculated can be used.

, @, The cold chamber 24 is kept airtight with respect to the bottom of the gasification chamber 10 through the sandwich flange device 40 .

The nozzle mixing burner 60 along with the slug tap member 20 is supported on the annular flange arrangement 40 and can be easily removed from the flange arrangement 40.

Next, FIG. 2 will be explained.

The slug tap member 20 consists of a body 42 of steel or copper alloyed metal cast around a helical coiled tube 44 with an inlet projecting from the base of the body for circulating cooling water. 46 and an outlet 48.

Tundis surface of slag tap member
h 5 surface , ) 50 is frustoconical and merges with the cylindrical surface of the slag discharge orifice 52 , which terminates in an annular lip 54 .

The outer peripheral surface 56 of the body 42 is preferably tapered for easy removal from the hearth of the gasification chamber.

The base of the body 42 has an annular recess 58 for coaxial engagement with an annular projection (not shown) on the sandwich flange arrangement.

In a particular example of a slug tap member, the coiled tube 44 is made of a nickel-chromium alloy (e.g., known as Inconel 600), has a length of approximately 42 inches, and has an inner diameter of 12 .7
mm (0,5 inch), wall thickness 3.175ii (0,12
5 inches).

The overall width of the casting body 42 is approximately 323.85 mm (12,75 mm).
inch), total height is approximately 114.3myz (4.5 inches)
Met.

The orifice 52 was approximately 2 inches in diameter and 1.5 inches in height and merged into the tundish surface at an angle of approximately 38 degrees to the horizontal.

Preferably, the casting length of the coiled pipe is cast −i
n length ) has a plurality of spaced apart rings on its outer surface to improve bonding with the cast metal, enhance heat transfer to the cooling fluid, and eliminate the tendency of the casting to break when cooled after the casting operation. Ribs 45 are provided.

The coiled tube is within the cast body and the convolutions extend around and near the surfaces of at least the tundish and orifice, preferably the convolutions near said surfaces are 6.35 to 3.81 degrees (0.0 , 25 to 1.5 inches).

The slug tap 6 begins by forming the tube 44 into the desired helical coil shape, supporting the tube by suitable means in a suitable mold, with an inlet 46 and an outlet 48 projecting, and the copper or copper alloy The main body 42 is manufactured by casting into a mold.

This manufacturing method provides good contact and thus allows the body 42
and the cooling conduit formed by tube 44.

[Brief explanation of drawings]

FIG. 1 is a schematic vertical cross-sectional front view of a fixed bed slagging gasifier, FIG. 2 is a cross-sectional front view of a detachable slag tap member of the gasifier shown in FIG.
The figure is a partial cross-sectional front view of the coiled tube in the slug tap material. Explanation of drawing numbers, 10... Pressurized gasification chamber, 16...
Tuyere, 18... hearth, 20... slag tap member,
24... Quenching chamber, 42... Main body of slag tap member (cast ingot), 44... Coiled pipe (cooling pipe), 46...
- Inlet, 48... Outlet, 50... Tundish surface, 52... Slag discharge orifice.

Claims (1)

[Scope of Claims] 1. Having an integrally formed metal tube for circulating cooling liquid through the solid cast mass, and having an upper tundish surface and a central slag discharge orifice through which slag discharged from the gasifier flows. said upper tundish surface slopes downwardly and inwardly and merges with said central slag discharge orifice, said tube passing through said cast mass; Stretch out,
and adjacent to the tundish surface and the orifice passage surface, and 6,35 to 38.
A slag tap for use in a coal slagging gasifier forming cooling conduits spaced at a distance of 1 mm, the ends of said tubes projecting outwardly from the surrounding cast metal mass to provide a cooling fluid inlet and outlet. Member 2. The slug tap member according to claim 1, wherein the cast metal ingot is made of copper or a copper alloyed metal. 3. The slag tap member according to claim 1 or 2, wherein the upper tundish surface of the slag tap member has a truncated conical shape, and the peripheral surface of the central slag discharge orifice has a right cylindrical shape. 4. The slag tap member according to any one of the preceding claims, wherein the outer peripheral surface of the slag tap member is tapered. 5 The above tube nickel-chromium or nickel-chromium-
A slug tap member according to any one of the preceding claims, constructed as a coil of alloyed metal. 6. A slug tap member as claimed in any one of the preceding claims, wherein the outer surface of the tube is provided with a plurality of spaced annular ribs for improving the bond with the surrounding cast metal. 7. The total width of the cast body is within the range of 304.8 to 330.2 mm, and the total height is within the range of 762 to 127 mm,
and the slag discharge orifice has a diameter within the range between 38.1 and 63.5 mm and a height within the range between 25.4 and 50.8 mm, and an angle within the range of 30-45° with respect to the horizontal. The slug tap member according to any one of claims 3 to 6, wherein the slug tap member is merged with the uppermost truncated conical surface. 8. A gasifier, a device for introducing coal into the gasifier to gasify the coal in the gasifier, and a device for introducing coal into the gasifier to gasify the coal in the gasifier. a device for introducing oxygen and steam, a hearth at the bottom of the gasifier and including a slag discharge orifice for discharging slag from the gasifier, below the slag discharge orifice;
a burner device for directing a stream of hot combustion products to a slag discharge orifice to maintain the slag in a molten state on the hearth; In a coal slagging gasifier comprising a quench chamber for removing slag, and a device for reducing or stopping the hot combustion gas flow to discharge slag from the slag discharge orifice, the slag discharge orifice is located within the hearth. defined as a substantially vertical passageway through a central, removable slug tap member, the slug tap member having an integrally formed metal tube for circulating cooling fluid through the solid cast mass; and comprising a solid cast mass of highly thermally conductive metal having an upper tundish surface through which the slag discharged from the gasifier flows and a central slag discharge orifice, said upper tundish surface sloping downwardly and inwardly. and merges with the central slag discharge orifice, the tube extending through the cast mass and adjacent the tundish surface and the surface of the orifice passage and extending from 6.35 to 38 mm from both surfaces. .1
Coal slagging gasifier forming cooling conduits spaced apart by a distance of mm, the ends of said tubes projecting outwardly from the surrounding cast metal mass to provide a cooling liquid inlet and outlet. 9 During operation of the gasifier, the exposed surfaces of the cast ingots that are in direct contact with the slag and burner gas are heated to 50°C to 40°C.
9. The coal slagging gasifier of claim 8, wherein a cooling liquid is circulated through said cooling tubes at a flow rate sufficient to maintain a temperature of 0<0>C. 10 The upper tundish surface is maintained at a temperature of 200 to 400°C, and the cylindrical surface of the orifice is maintained at a temperature of 100 to 400°C.
The coal according to claim 9, wherein the cooling liquid is circulated at a flow rate such that the temperature is maintained at 00°C and the lowest part of the surface of the slag tap adjacent to the burner is maintained at a temperature of 50 to 400°C. Slugging gasifier.