Method and Apparatus for Continuously Mixing and Kneading Pulverulent Bodies Such as Pulverized Coal, Oil Coke to Prepare Slurry Thereof

1. Field of the Invention:

This invention relates to a method and apparatus for continuously mixing and kneading pulverulent bodies such as pulverlized coal, oil coke supplied continuously by a fixed quantity to prepare slurry thereof, and more particularly to, a method and apparatus for continuously mixing and kneading which can be mixing and kneading pulverulent bodies into the thixotropic state while humidifying them under the grain state (primary grain state).

2. Description of the Prior Art:

Conventionally, when pulverulent bodies supplied continuously are humidified, mixed and kneaded, it is an extremely important and difficult problem how to humidify uniformly the pulverulent bodies and through what mixing and kneading system they should be passed.

We previously proposed a continuously mixing method and an optimum apparatus for carrying out the method in which liquid is adapted to flow down as an annular overflow film and the pulverulent bodies supplied continuously by a fixed amount are dispersed and collide with the liquid while being mixed with the liquid with a rotary mixing disk (for example, Japanese Patent Publication Nos. Sho 48-22511, Sho 53-38828, sho 55-32755 and Sho 57-9844,). However, when the pulverulent bodies such as pulverlized coal, oil coke are made into a slurry, a mixing and kneading system must be ensured for more adequate mixing and kneading.

A prior general means for mixing and kneading the pulverulent bodies sufficiently comprises a humidifying means and a mixing and kneading means separated therefrom for repeatedly mixing and kneading with a plurality of mixing and kneading devices.

In said conventional means for repeating the mixing and kneading, a plurality of mixing and kneading devices are needed. Thus, the transfer speed of material between the devices is varied and the quality of the material is degraded so that the cost of equipment ot prevent the device from such variation and degradation is disadvantageously obliged to increase.

An object of the present invention is to provide a continuously mixing and kneading method and apparatus to carry out this method for preparing a slurry of pulverulent bodies such as pulverlized coal, oil coke in which prior defects are overcome and pulverulent bodies supplied continuously in a fixed amount (i.e. at a fixed rate) can be uniformly humidified in the grain state (primary grain state), collected in the swelling state and sent to a mixing and kneading system, in which time taken for passing the pulverulent bodies through the mixing and kneading system can be extended as long as possible to achieve sufficient mixing and kneading with a passing shearing force.

In the continuously mixing and kneading method according to the present invention for preparing a slurry of pulverulent bodies such as pulverlized coal, oil coke, the pulverulent bodies continuously supplied in a fixed amount from a supply tube 10 are spattered and dispersed by a rotary mixing disk 3 rotating in a mixing chamber 1 covered with a base plate 2. Main liquid is adapted to flow down as an annular outflow film along an outflow tube 25 of an inverse conical type with respect to these spattered and dispersed pulverulent bodies while a small amount of liquid such as an additive is jetted from a plurality of injection nozzles 4 to humidify the pulverulent bodies uniformly with a plurality of upper surface scrapers 5 provided on said rotary mixing disk 3 and disposed to cross the parts of said injection nozzle as said disk rotates and side face scrapers 7 provided on said rotary mixing disk 3 and turned along the inner wall of said mixing chamber. The pulverulent bodies are collected in the center with collecting blades 8 to be supplied to a next stage mixing and kneading chamber 6 and dispersed centrifugally with a rotary mixing and kneading disk 9 rotating in the mixing and kneading chamber 6, while being mixed and kneaded with fixed mixing and kneading pins 1 disposed on the upper wall of said mixing and kneading chamber 6 and movable mixing and kneading pins 12 planted in said rotary mixing and kneading disk 9 and discharged from a discharge port 14 with a mixing and kneading type scraper blade 13 provided on said rotary mixing and kneading disk 9.

Also, there is provided a continuously mixing and kneading apparatus which according to the present invention comprises the mixing chamber 1 covered with the base plate 2, the supply tube 10 connected to a fixed amount supply unit, for supplying continuously the pulverulent bodies in a fixed amount, the rotary mixing disk 3 disposed in the mixing chamber 1 for spattering and dispersing the pulverulent bodies supplied from the supply tube 10, the outflow tube 25 of inverse conical type disposed on the upper central portion of the mixing chamber for flowing down main liquid as an annular outflow film with respect to the spattered and dispersed pulverulent bodies, a plurality of injection nozzles 4 for injecting further a small amount of liquid such as additives with respect to said spattered and dispersed pulverulent bodies, a plurality of upper surface scrapers 5 provided on said rotary mixing disk 3 and arranged to cross said injection nozzle ports as the rotary mixing disk rotates, the side face scrapers 7 provided on said rotary mixing disk 3 to turn along the inner wall of said mixing chamber, the collecting blades 9 disposed on the bottom of said mixing chamber 1 to collect the pulverulent bodies in the center, the mixing and kneading chamber 6 provided on the next stage of said mixing chamber, the rotary mixing and kneading disk 9 disposed in the mixing and kneading chamber 6 to disperse centrifugally the pulverulent bodies humidified and supplied from said mixing chamber 1, the fixed mixing and kneading pins 11 secured to the upper wall of the mixing and kneading chamber 6, the movable mixing and kneading pins 12 planted in said rotary mixing and kneading disk 9 and the mixing and kneading type scraper blade 13 provided on said rotary mixing and kneading disk 9 to discharge the mixed and kneaded pulverulent bodies to the discharge port 14.

While the pulverulent bodies supplied continuously from the supply tube 10 in a fixed amount are spattered and dispersed with the rotary mixing disk 3 rotating with high speed in the mixing chamber 1, main liquid supplied from a pipe 23 enters a liquid chamber 24, the overflowed main liquid flows down along the overflow tube 25 of inverse conical type and a small amount of liquid such as additives is injected from the injection nozzles 4. Then, as said rotary mixing disk 3 rotates, the upper surface scraper 5 rotates to cross the injection nozzle port 4a while the side face scraper 7 turns so that the liquid uniformly humidifies the spattered and dispersed pulverulent bodies by the action of these scrapers in the primary grain state. The pulverulent bodies thus humidified are collected with the collecting blade 8 disposed on the bottom of the mixing chamber 3 to be sequentially supplied from a central drop port 16 into the lower stage mixing and kneading chamber 6.

In this collecting process, the pulverulent grains are humidified and swelled. In the mixing and kneading chamber 6 is rotated the rotary mixing and kneading disk 9, at high speed and the pulverulent bodies supplied from said drop port 16 are dispersed with the rotary mixing and kneading disk 9. Since the fixed and movable mixing and kneading pins 11,12 are planted respectively in the upper wall of the mixing and kneading chamber 6 and in the rotary mixing and kneading disk 9, the pulverulent bodies are securely mixing and kneaded into the thixotropic state by a passing shearing force caused by the passage of the pulverulent bodies between these pins to reach the bottom of the mixing and kneading chamber. On the bottom of the mixing and kneading chamber is rotated the mixing and kneading type scraper blade 13 to discharge the slurry of the pulverulent bodies from the discharge port 14.

The apparatus has the humidifying system and mixing and kneading system arranged in a double stage from such that the pulverulent bodies in the mixing chamber pass through the humidifying and mixing system for spattering, dispersing, humidifying, mixing and collecting to be supplied to the mixing and kneading chamber in which they pass through the mixing and kneading system to be dispersed, mixed, kneaded, scraped out and discharged. The time taken for the passage of the pulverulent bodies through the apparatus can be extended as long as possible and further the apparatus itself can be made compact. If the mixing and kneading in the mixing and kneading system is insufficient, a plurality of stages of the system may be provided, if desired.

In the continuously mixing and kneading method for preparing the slurry of pulverulent bodies such as pulverized coal, oil coke according to the present invention, the pulverulent bodies supplied continuously in a fixed amount from the supply tube 10 are spattered and dispersed by the rotary mixing disk 3 rotating with high speed in the mixing chamber 1, while the main liquid flows down as the overflow film along the overflow cone 20, and further a small amount of liquid such as additives is injected from the injection nozzle 4. Then, the upper surface scraper 5 rotates to cross the injection nozzle port 4a as said rotary mixing disk 3 rotates, while the side face scraper 7 turns so that the liquid is mixed uniformly with the spattered and dispersed pulverulent bodies by the action of these scrapers to humidify the pulverulent bodies into the primary grain state. The pulverulent bodies thus humidified are collected by the collecting blade 8 disposed on the bottom of the mixing chamber 3 to be sequentially supplied from the central drop port 16 into the lower stage mixing and kneading chamber 6 so that the pulverulent grains can be uniformly humidified and swelled in this collecting process.

The pulverulent bodies supplied from said drop port 16 into the mixing and kneading chamber 6 are dispersed by the rotary mixing and kneading disk 9, mixed and kneaded by the fixed mixing and kneading pins 11 fixed to the upper wall of the mixing and kneading chamber 6 and the movable mixing and kneading pins 12 planted in the rotary mixing and kneading disk 9 so that the pulverulent bodies can be securely mixed and kneaded into the thixotropic state by the passing shearing force produced with the passage of the pulverulent bodies between these pins to be made into a slurry, and discharged from the discharge port 14.

The continuously mixing and kneading method according to the present invention has the humidifying system and the mixing and kneading system arranged in the double stage form. The pulverulent bodies in the mixing chamber pass through the humidifying and mixing system for spattering, dispersing, humidifying, mixing and collecting to be supplied into the mixing and kneading chamber and then pass through the mixing and kneading system for dispersing, mixing, kneading, scraping and discharging. Therefore, the time taken for the passage through the apparatus can be extended as long as possible and further the apparatus itself can be made compact.

The above-mentioned and other objects and features of the invention will become apparent from the following detailed description taken in conjunction with the drawings which indicate an embodiment of the invention.

The drawings illustrate apparatus for carrying out a continuously mixing and kneading method for preparing the slurry of pulverulent bodies such as pulverlized coal, oil coke in which;

FIG. 1 is a longitudinal sectional view of the apparatus;

FIG. 2 is a side view of the same;

FIG. 3 is a plan view of the same;

FIG. 4 is a sectional view taken along the line A--A in FIG. 1;

FIG. 5 is a sectional view taken along the line B--B in FIG. 1; and

FIG. 6 is a sectional view showing another constitutional embodiment.

The mixing chamber 1 is formed in a cylinder 21 having a bottom plate 22 and covered with the base plate 2 having a circular hole 2a in the center. The bottom plate 22 is formed in the center with a drop port 16. On the lower stage side of said mixing chamber 1 is disposed a shell 15 consisting of a cylindrical portion 15a and a conical portion 15b connected to the lower portion thereof to thus form the mixing and kneading chamber 6 in the interior. The mixing and kneading chamber 6 is formed on one side of the lower portion with the discharge port 14. A shaft 17 supported by bearings 18 is disposed to extend through the mixing and kneading chamber 6 and the mixing chamber 1 and rotate with high speed through the direct connection to a V-pulley 19 or other drive units. In said mixing chamber 1 is disposed the rotary mixing disk 3 secured to said shaft 17 and in said mixing and kneading chamber 6 is disposed the rotary mixing and kneading disk 9 secured to said shaft 17. For example, the supply tube 10 is connected to the outlet side of the unit (not shown) developed by us for supplying continuously a fixed amount of the pulverulent bodies or the like, and the fixed amount of the pulverulent bodies are continuously sent from said unit to the center of said rotary mixing disk 3 to be spattered and dispersed by the rotary mixing disk 3. To supply main liquid to spattered and dispersed pulverulent bodies, said base plate 2 is provided on the center of the upper surface thereof with an overflow cone 20 to flow down the main liquid along an overflow tube 25 as an annular overflow film. Further, a plurality of injection nozzles 4 to jet and mix a small amount of liquid such as additives are symmetrically disposed on said base plate 2, and nozzle ports 4a are adjacent the mixing chamber 1. Further, an amount of humidified pulverulent bodies can be set by making the kind of liquid injected from said injection nozzle 4 the same as the main liquid according to the slurry state to be prepared, and detergent to wash the interior of the unit may be supplied from the overflow cone 20. This overflow cone 20 serves such that the main liquid supplied from a pipe 23 enters a liquid chamber 4 and the overflowed main liquid flows down as the annular overflow film along an inverse conical type overflow tube 25 and collides with the pulverulent bodies spattered and dispersed by said rotary mixing disk 3 to be uniformly mixed and humidified. A plurality of states may be of course be provided on this overflow cone 20, as shown in the Japanese patent publication No. Sho 57-9844, to thus supply and mix a plurality of kinds of main liquid.

A plurality of the upper surface scrapers 5 (three scrapers in the embodiment) are mounted radially at a same angle of circumference on said rotary mixing disk 3 to cross said injection nozzle port 4a as the rotary mixing disk rotates and further scrape off the pulverulent bodies which may be attached to the inner wall surface of said base plate 2. A plurality of (three in the embodiment) side face scrapers 7 are radially mounted on the peripheral side of said rotary mixing disk 3 to turn and scrape off the pulverulent bodies along the inner wall of said mixing chamber. Also, a plurality of mixing pins 26 are planted in the upper surface of the rotary mixing disk 3 to be used according to the usage.

On the bottom of said mixing chamber 1, i.e., on the upper surface of said bottom plate 22 are disposed a plurality of (three in the embodiment) L-sectioned collecting blades 8 to collect the humidified pulverulent bodies to the center so that the collected pulverulent bodies are dropped and supplied from said drop port 16 to the central portion of the mixing and kneading chamber 6. In the upper wall of said mixing and kneading chamber 6, i.e., in the lower surface of said bottom plate 22 are planted a plurality of fixed mixing and kneading pins 11, and in the upper surface of said rotary mixing and kneading disk 9 are planted a plurality of movable pins 12 at positions in which they can pass between said fixed mixing and kneading pins 11. Further, a bottom member 27 having a conical portion 27a is disposed on the lower portion of said conical portion 15b, and the bottom of said mixing and kneading chamber 6 is formed in the form of valley by said conical portions 15b, 27a while said discharge port 14 is formed in a portion of said conical portion 15b. The mixing and kneading type scraper blade 13 mounted on the lower surface of said rotary mixing and kneading disk 9 has the lower end shaped to correspond to the valley-like bottom of said mixing and kneading chamber 6.

Further, while one stage of the mixing and kneading system is described in the constitutional example shown in FIGS. 1 and 2, multiple stages of the mixing and kneading systems, as shown in FIG. 6, may be of course provided according to the pulverulent bodies or the state of slurry to be prepared.

Next, the continuously mixing and kneading method according to the present invention will be described with reference to an operational example of the apparatus. The pulverulent bodies supplied continuously in a fixed amount, i.e., at a fixed rate from the supply tube 10 are spattered and dispersed by the rotary mixing disk 3 rotating with high speed in the mixing chamber 1. The main liquid flows down from the overflow tube 25 of the overflow cone 20 to the pulverulent bodies as an annular overflow film and collide with the pulverulent bodies to provide a uniform misture. Further, while a small amount of liquid such as additives is injected in the form of spray from the injection nozzles 4 arranged symmetrically into the mixing chanber 1, the liquid is mixed uniformly with the spattered and dispersed pulverulent bodies by the action of the upper surface scrapers 5 and the side face scrapers 7 provided on the rotary mixing disk 3 so that the pulverulent bodies are humidified in the primary grains states. The pulverulent bodies thus humidified are collected by the collecting blade 8 disposed on the bottom of the mixing chamber 3 to be sequentially supplied from the central drop port 16 into the lower stage mixing and kneading chamber 6. In this collecting process, the pulverulent grains are uniformly humidified and swelled.

The rotary mixing and kneading disk 9 is rotated with high speed in the mixing and kneading chamber 6 and the humidified pulverulent bodies supplied from said drop port 16 are dispersed centrifugally by the rotary mixing and kneading disk 9. Since the fixed mixing and kneading pins 11 and the movable mixing and kneading pins 12 are planted respectively in the upper wall of the mixing and kneading chamber 6 and in the rotary mixing and kneading disk 9, the pulverulent bodies are securely mixed and kneaded into a thixotropic state with the passing shearing force produced by the passage of the pulverulent bodies between these pins, and then reach the bottom of the mixing and kneading chamber. The mixing and kneading type scraper blade 13 is rotated on the bottom of the mixing and kneading chamber to discharge the slurry of the pulverulent bodies from the discharge port 14.

Further, said embodiment is not only applied to the preparation of a slurry of pulverulent bodies such as pulverlized coal, oil coke, but also to the humidifying, mixing and kneading of other pulverulent bodies.