US3902872A - Reactor for gasifying coal under pressure - Google Patents

Abstract

A reactor for the continuous gasification of coal under superatmospheric pressures and elevated temperatures with oxygen and water vapor and, if desired, additional gasifying agents is disclosed and includes a rotatable coal feeder disposed in the upper portion of the reactor having at least one feed chute. The longitudinal axis of the feed chute extends at an acute angle alpha to the vertical, which angle opens opposite to the direction of rotation of the feeder, and the leading edge of the outlet opening of the revolving feed chute is turned outwardly from a radial direction by an acute angle epsilon of from 5-20 degrees.

Description

United States Patent Rudolph Sept. 2, 1975 [54] REACTOR FOR GASIFYING COAL UNDER 2,113,015 4/1938 Daniels 48/86 R PRESSURE 2,143,987 1/1939 Koller 48/86 R 2,187,872 1/1940 Winkler 6t 211...... 48/202 X [75] Inventor: Paul R lph, B H m rg, 2,689,786 9 1954 Hubmann 48/77 x Germany [73] Assignee: Metallgesellschaft Aktiengesellschaft, Primary Examiner Serwin Frankfurt am Main, Germany Attorney, Agent, or FzrmBurgess, Dlnklage & Sprung [22] Filed: Sept. 10, 1974 Appl. No.: 504,479

Foreign Application Priority Data Oct. 22, 1973 Germany 2352900 References Cited UNITED STATES PATENTS 11/1920 Corthesy 48/73 X 7/1931 Daae 48/86 R [5 7 ABSTRACT A reactor for the continuous gasification of coal under superatmospheric pressures and elevated temperatures with oxygen and water vapor and, if desired, additional gasifying agents is disclosed and includes a rotatable coal feeder disposed in the upper portion of the reactor having at least one feed chute. The longitudinal axis of the feed chute extends at an acute angle alpha to the vertical, which angle opens opposite to the direction of rotation of the feeder, and the leading edge of the outlet opening of the revolving feed chute is turned outwardly from a radial direction by an acute angle epsilon of from 5-20 degrees.

4 Claims, 3 Drawing Figures REACTOR FOR GASIFYING COAL UNDER PRESSURE BACKGROUND This invention relates to a reactor for a continuous gasification of coal under superatmospheric pressures and elevated temperatures by a treatment with oxygen and water vapor and, if desired, additional gasifying agents, comprising a rotatable coal feeder, which is disposed in the upper portion of the reactor and comprises at least one feed chute. v

Reactors of that kind consist usually of a cylindrical pressure vessel, which is suitably provided with a water jacket and contains in its lower end a rotary grate, which cooperates with an ash discharge lock. The conduits for feeding the gasify'ing agent may open in that rotary grate. A pressure lock is provided at the top end of the reactor and serves for feeding the coal to be gasified. Means for withdrawing the tar-containing raw gas which is produced are also provided. Known reactors have been described in the German Pat. No. 1,021,116 and the US. Pat. No. 2,925,334.

In such continuously operating pressure reactors the coal in the dense coal bed descends toward the rotary grate while the coal is progressively gasified and the ash content of the coal increases continuously. At the same time, new coal is continuously sprinkled from the feeder onto the fuel bed. It has been found in the operation of known reactors that the feeding of coal is not always satisfactory. Particularly in the gasification of caking coal the material to be gasified swells so that the volume of coal or coke in the top portion of the gas producer is increased. As a result, the surface of the coal bed rises like the surface of a foaming liquid above the edge of the coal outlet opening. Such rise and swelling of the uppermost portion of the coal bed may easily cause a caking adjacent to the feed chute for the coal. That caking may eventually result in a clogging of the outlet opening of the chute for feeding the coal so that the operation of the gas producer is critically disturbed.

SUMMARY The invention avois the disadvantages of the prior art and ensures that the coal is applied to the uppermost layer of the coal bed in a uniform and troublefree manner. This is accomplished according to the invention in that the longitudinal axis of the feed chute extends at an acute angle a to the vertical, which angle opens opposite to the direction of revolution, and that the leading edge of the outlet opening of the revolving feed chute is turned outwardly from a radial direction by an acute angle 6 of 20. As a result of this design of the feed chute, a component of motion which opposes the direction of rotation of the feeder is imparted to the coal and bed coal which contacts the leading edge of the outlet opening can readily flow radially outwardly along said edge so that a build-up of coal is avoided.

The leading wall of the feed chute desirably rises at an angle 5 of 3060 from the horizontal. In that case the coal is not plowed by the feed chute as is usual with known feeders. The leading wall now slides over the surface of the coal bed and exerts a downward pressure thereon so that the compaction of the swelling coal is promoted.

A further development of the invention resides in that the leading edge of the outlet opening of the feed chute is disposed below the trailing edge thereof and the angle of rise 7 amounts to about 3l0 from the horizontal. This feature additionally facilitates the flowing of coal from the feed chute and further reduces the likelihood of trouble. v

DESCRIPTION F THE DRAWING The inventionwill now be explained with reference to an example shown on the drawing, in which FIG. 1 is a diagrammatic longitudinal sectional view showing the upper portions of a reactor for a pressure DESCRIPTION The gasification reactor comprises a doublewalled pressure vessel 1 and 2, which contains an internal water jacket 3. The upper portion of the reactor contains a coal container, the walls of which are also watercooled. The coal in container 4 rests on a rotatable distributor disc 5, which is secured to a hollow shaft 6, which is guided in bearings 7 and 8. A substantially cylindrical displacement body 9 is connected to the distributor disc 5 and projects downwardly and carries stirrer arms 10 and 11. A cooling water conduit 12 extends in the hollow shaft 6 and serves to cool the displacement body 9 and by means of branch conduits also the two stirrer arms 10 and 11.

In operation, coal is fed from the supply in the container 4 through the distributor disc 5 and its two feed chutes 13 and 14 continuously onto the coal bed 15. The coal is gasified in the coal bed 15, and the gaseous reaction products are withdrawn through conduit 16 and supplied to further use.

Reference is made to FIGS. 2 and 3 for an explanation of the design and arrangement of the feed chutes 13 and 14. During a rotation of the disc 5, the chutes move in the direction of the arrow P and the coal flows downwardly onto the coal bed. The coal moves in the chutes 13 and 14 approximately along their longitudinal axis A, which includes an acute angle a (FIG. 3) with the vertical. The angle a may amount to about 822. The chute is inclined by this angle a in such a direction that a component of motion which opposes the rotary motion (arrow P) is imparted to the coal as it flows through the chute. This facilitates the flowing of coal onto the coal bed 15. This outflow is further facilitated in that the trailing edge 17 is disposed above the leading edge 18 so that the plane of the outlet opening 19 of the feed chutes 13 and 14 is inclined from the horizontal plane by an angle a (FIG. 3) amounting to The leading wall 20 of each feed chute extends from the leading edge 18 of the chute and is upwardly inclined at an acute angle a (FIG. 3) which preferably amounts to 306O The provision of this inclined leading wall 20 prevents a buildup of coal before the leading wall during a rotation of the chutes 13 and 14 in the direction of the arrow P. Rather than plowing up the coal of the bed 15, the leading wall 20 even exerts a certain downward pressure during the rotation of the feeder. This design is particularly desirable for highly swelling coal.

It is apparent from FIG. 2 that the leading edge 18 of chutes 13 and 14 includes an acute angle 6 (FIG. 2)

with the radial line R. The leading edge 18 is turned back outwardly, toward the housing wall 2, by that angle 6. As a result, that end of the leading edge 18 which adjoins the displacement body 9 leads the other end so that a sliding guide is provided for the coal which contacts the leading edge 18 and the leading wall and said coal flows off outwardly in the direction from the displacement body 9 toward the housing wall 2. This feature prevents the occurrence of a dead angle between the displacement body 9 and the chute 13 or 14 and an accumulation of coal in such dead angle.

What is claimed is:

l. Reactor for the continuous gasification of coal under superatmospheric pressures at elevated temperatures by treatment with oxygen and water vapor and, if desired, additional gasifying agents, comprising rotatable coal feeder means disposed in the upper portion of the reactor and having at least one feed chute means, the longitudinal axis of said feed chute means extending at an acute angle alpha to the vertical, said angle opening opposite to the direction of rotation, the leading edge of the outlet opening of said feed chute means being turned outwardly from a radial direction by an acute angle epsilon of 520.

2. Reactor of claim 1 wherein the leading surface of the feed chute rises at an angle of 3060 from the horizontal.

3. Reactor of claim 1 wherein the leading edge of the outlet opening of the feed chute is disposed below the trailing edge thereof and the angle of rise alpha of about 3-l0 from the horizontal.

4. Reactor of claim 1 wherein the outlet opening adjoins the outside of a displacement body extending downwardly below the outlet opening and having at least one radial stirrer arm disposed below the surface of the coal bed during operation.

Claims (4)

1. REACTOR FOR THE CONTINUOUS GASIFICATION OF COAL UNDER SUPERATMOSPHERIC PRESSURES AT ELEVATED TEMPERATURES BY TREATMENT WITH OXYGEN AND WATER VAPOR AND, IF DESIRED, ADDITIONAL GASIFYING, AGENTS, COMPRISING ROTATABLE COAL FEEDER MEANS DISPOSED IN THE UPPER PORTION OF THE REACTOR AND HAVING AT LEAST ONE FEED CHUTE MEANS, THE LONGITUDINAL AXIS OF SAID FEED CHUTE MEANS EXTENDING AT AN ACUTE ANGLE ALPHA TO THE VERTICAL, SAID ANGLE OPENING OPPOSITE TO THE DIRECTION OF ROTATION, THE LEADING EDGE OF THE OUTLET OPENING OF SAID FEED CHUTE MEANS BEING TURNED OUTWARDLY FROM A RADIAL DIRECTION BY AN ACUTE ANGLE EPSILON OF 5*-20*.

2. Reactor of claim 1 wherein the leading surface of the feed chute rises at an angle of 30*-60* from the horizontal.

3. Reactor of claim 1 wherein the leading edge of the outlet opening of the feed chute is disposed below the trailing edge thereof and the angle of rise alpha of about 3*-10* from the horizontal.

4. Reactor of claim 1 wherein the outlet opening adjoins the outside of a displacement body extending downwardly below the outlet opening and having at least one radial stirrer arm disposed below the surface of the coal bed during operation.

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