JPS631893B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an underwater granulation device, and in particular, prevents the production of ungranulated coal during abnormalities such as startup and shutdown, and maintains a normal state at an early stage. The present invention relates to an underwater granulation process suitable for.

Conventionally, there are several examples of underwater granulation processes, but they all relate to processes during normal operation, such as during start-up,
No countermeasures for abnormal conditions during shutdown are described.

That is, in an abnormal state, there is a need to take measures to deal with non-uniform quality at startup and to deal with the residue of the production process within the device at shutdown.

An object of the present invention is to provide an underwater granulation device that can quickly produce granulated products of uniform quality from the initial stage of production, taking into account measures against abnormalities that are necessary for practical use.

The main point of the present invention is that, as a basic configuration, a plurality of underwater granulation devices each having a plurality of stirring tanks connected in series are combined in parallel, and the upper stirring tank of one of the plurality of parallel series is connected to the upper stirring tank of one series of the plurality of parallel series. It has a structure in which a return pipe is connected to the final stage stirring tank via a pump, and unfinished granules and system residue from other series are returned to one series using the return pipe. Re-granulation produces normal quality, and other series produce normal quality from the beginning, overall, it accelerates the start of high quality production of the granulation equipment and prevents the production of low quality granules. It is in the point of doing.

An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.

FIG. 1 is a diagram illustrating one series of the underwater granulation apparatus of the present invention, in which coal/water pulp 1 as a raw material is passed through a pulp conditioning tank 2 to a first stage stirring tank 3.
will be transferred to. A binder 4 is supplied to the first stage stirring layer 3, and the first step of granulation begins here. Thereafter, granulation proceeds through the second-stage stirring tank 5, the third-stage stirring tank 6, and the fourth-stage (final stage) stirring tank 7, and granulated coal is produced from the outlet 8 together with the waste water. Also,
A return pipe 9 branched from the outlet 8 is returned to the first stage stirring tank 3 via a pump 10.

Figure 2 is a schematic diagram of this plant configured with two lines in parallel.The stirring tanks in each stage of the second line are arranged in order from the top to 3a, 5a, 5a,
6a and 7a are also displayed.

Fig. 3 is a schematic diagram of this plant configured with three parallel trains, and the stirring tanks in each stage of the third train are ordered from the top to 3b, 5b,
6b and 7b are also displayed.

As shown in Fig. 2 and Fig. 3, return piping 9, 9 is provided from the final stage stirring tank 7, 7a, 7b of each series.
Both a and 9b are the first stirring tank 3 of the first series.
It has been returned. Second series final stage stirring tank 7a
is equipped with an outlet 8a, and the final stage stirring tank 7b of the third series is equipped with an outlet 8b.

Next, the operation will be explained. During normal operation, coal/water pulp 1 is used in any of the 1st to 3rd lines.
100% capacity is supplied, and in the case of 1 train, from exit 8
Granulated coal is produced at 100%, in the case of two lines, 50% each from outlets 8 and 8a, and in the case of three lines, 33.3% each from outlets 8, 8a, and 8b.

Next, let's think about the time of startup. Generally supplied coal/water pulp 1 has a coal concentration of 30 to 50%. Therefore, during the suspension period, the pulp adjustment tank 2 should be
During the piping, the water condition and the coal/water pulp condition are such that the coal concentration is lower than 30%. In addition, each stirring tank in the granulation device is either completely empty, filled with water, or in an intermediate state of granulation. Therefore, after starting up, 1
Since the granulation process does not occur normally for ~2 hours, the products from the outlets 8, 8a, 8b are often not of normal quality. In particular, it may be produced in an ungranulated state. Products that are not of normal quality cannot be sent to the next process, so pipe 9
(including 9a and 9b in the case of 2 to 3 series), returns to the first stage stirring tank 3 of the 1st series, goes through the granulation process again, and is granulated until normal quality is obtained, and then the outlet 8 produce more. This re-granulation is usually required once or twice.

If such regranulation is performed in the case of one series, the coal/water pulp 1 will be continuously supplied, which will cause it to be confused with that of the regranulation process, making it difficult to maintain a constant quality. Further, during the regranulation process, the amount of coal/water pulp 1 to be supplied is limited, resulting in operation with reduced capacity. And because the supplied coal/water pulp 1 and the regranulated material are mixed up,
It is also unclear when to restore normal capacity operation, making operation control extremely difficult.

In the case of two series, the above-mentioned abnormal coal that requires re-granulation can be concentrated and re-granulated in the first series using the return pipes 9 and 9a, and the other series is used for normal coal. - Normal operation can begin from the moment water pulp 1 starts being supplied, and granulated coal of uniform quality can be produced.

Furthermore, if there are three trains, the second train can be put into normal operation at an earlier point.

Of course, even in the case of 2-line or 3-line systems, the normal operation capacity decreases to 50% and 66.7%, respectively, during the period when regranulation is repeated in the first line. Therefore, if you want to quickly increase normal operation ability, it is clear that the more trains you have, the better, but the more trains you have, the more things that will require abnormal regranulation at start-up. This puts a strain on the regranulation process, making it necessary to increase the number of regranulation processes, and it becomes impossible to improve the normal operating capacity. In our experience, the limit is one regranulation series versus two or three normal series.

From the above point of view, it is believed that the three trains shown in FIG. 3 or four trains, which is an additional one train, is the optimal number of trains to quickly improve normal operation capability.

The same applies to shutdowns; the more series there are, the better. In other words, when the inside of the stirring tank is replaced with water after a shutdown, the ungranulated coal remaining in the stirring tank is successively pushed out with water and brought to the first train, where the granulation is circulated. By repeating this process, the only ungranulated materials remaining in the end are those that remain within one series.

As described above, processing at start-up and shutdown times is facilitated, and normal operation can be accelerated by bringing up the capacity close to normal capacity.

As described above, the present invention includes parallel granulation series and a return pipe provided between the upper stage of one series and the final stage of another series, thereby preventing the production of incompletely granulated products. Moreover, since the production time of normal quality can be obtained early at the time of start-up, the effect of producing granules of uniform quality quickly and from the initial stage of production can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic elevational view showing one series of the underwater granulation device of the present invention, FIG. 2 is a schematic plan view of the underwater granulation device of the present invention with two series, and FIG. FIG. 2 is a schematic plan view of the underwater granulation device of the present invention. 1...Coal/water pulp, 2...Pulp adjustment tank,
3, 3a, 3b...first stage stirring tank, 5, 5a, 5
b... Second stage stirring tank, 6, 6a, 6b... Third stage stirring tank, 7, 7a, 7b... Final stage stirring tank, 8,
8a, 8b... Outlet, 9, 9a, 9b... Return piping, 10... Pump.

Claims (1)

[Scope of Claims] 1. A plurality of underwater granulation apparatuses each having a series of a plurality of stirring tanks connected in series are combined in parallel, and an upper stirring tank of one series among the plurality of parallel series and a final stage of the other series are combined. A multi-row underwater granulation device characterized by a return pipe connected to the stage stirring tank via a pump. 2. The multi-row underwater granulation device according to claim 1, characterized in that the series includes at least three series.