JPH0796158A - Orifice and submerged granulator using the same - Google Patents

Abstract

PURPOSE:To provide a submerged granulator having a required holdup by installing a flow resistance area from which turbulence is generated on the outlet side of the opening of an orifice. CONSTITUTION:An object to be granulated is continuously fed as a suspension from a raw material feeding port and, at the same time, a binder is fed from a finder feeding port and the two are stuck and coagulated to each other by agitation, etc., and further compacted to form a granulated body. At that time, an orifice is provided in the outlet part of a granulated layer and a notch, etc., are provided on the outlet side of the opening of the orifice. Then, a vigorous turbulent field is formed there to control the leak of the granulated body. In this way, long-time continuous granulation becomes possible and work efficiency is improved and maintenance cost is suppressed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a submerged granulator in which a finely divided substance is granulated in the presence of a binder from a suspension of the finely divided substance and a liquid. The present invention relates to an orifice required for maintaining a residence time and performing stable continuous granulation, and a submerged granulator using the orifice.

[0002]

2. Description of the Related Art In the case of separating and collecting only solids from a suspension in which a fine powdery solid is mixed in a liquid, application of a submerged granulation method has been proposed and put into practical use. This is because the second liquid, which is insoluble in the suspension medium that forms the suspension and is compatible with the solid that is the suspended substance, is added and mechanical energy such as stirring or vibration is applied to create the solid. It is separated as granules or aggregates. For example, when pulverized coal is suspended in water to form a slurry, and when heavy oil is used as a binder for submerged granulation, the coal content in the pulverized coal has an affinity for heavy oil and is separated into granular granules. You can take it out. Such submerged granulation is generally performed as a continuous process. In this case, in order to stably carry out continuous granulation, it is necessary to constantly hold a fixed amount of granules in the granulation tank.
This is usually referred to as Hold up.

The retention amount of the granulation body in the granulation tank due to hold-up, which varies depending on the granulation object, is indicated by the ratio to the effective volume of the granulation tank, and the proper value is the stabilization of continuous granulation. Is important to. When the amount of the raw material suspension supplied to the granulator is constant, the holdup is generally adjusted by the size of the orifice opening. That is, the gap is made smaller when the amount of retained granules due to hold-up is increased, and the gap is made larger when the amount of retained granules is decreased. However, adjustment of hold-up is insufficient only with the size of the gap, and it is often experienced that the target granule formation is difficult.

[0004]

[Object] An object of the present invention is to provide an orifice having a new structure that enables necessary hold-up and a submerged granulator using the same.

[0005]

According to a first aspect of the present invention, in an orifice provided at an outlet of a submerged granulation tank, a flow resistance region sufficient to generate a turbulent flow is provided at an outlet side of an orifice opening. The present invention relates to an orifice for a submerged granulator.

In the case of a streamline type in which the shape on the outlet side of the orifice opening changes smoothly along the flow of liquid, a laminar flow is easily formed, and the amount of retention due to holdup tends to be smaller than necessary. In such a case, if the gap between the orifice openings is made smaller to increase the retention amount, the supply amount of the raw material suspension is limited, and the granules are clogged, broken or adhered in the gap. It causes troubles and is not preferable. In order to maintain a predetermined hold-up while maintaining the gap of the orifice opening at a constant value, it is effective to form a turbulent flow such as a vortex on the discharge side and develop resistance to the flow. The turbulent flow has a Reynolds number of 1 to 9 × 10 ⁵ , particularly 3 to 8
It is preferably set to × 10 ⁵ . The flow resistance zone can be achieved, for example, by providing a notch on the outlet side of the orifice opening.

A second aspect of the present invention is characterized by comprising a cylindrical granulation tank containing a rotary shaft equipped with a large number of stirring blades, and an orifice according to claim 1 provided on the outlet side thereof. The present invention relates to a submerged granulating device.

There are two types of in-liquid granulation: underwater granulation and oil granulation. Underwater granulation involves suspending a finely divided substance that is an object to be granulated in water as a suspension medium, and using a second liquid that is insoluble in water and has an affinity for the finely divided substance as a binder. By using a mechanical external force such as stirring or vibration, the fine powdery substance is aggregated and consolidated to separate it as a granule. The main difference from the underwater granulation is that in the oil granulation, an organic liquid other than water such as hydrocarbon or carbon tetrachloride is used as a suspension medium and water is generally used as a binder. Underwater granulation,
Both the in-oil granulation has a batch type and a continuous type, and the orifice according to the present invention is applied to the continuous type. It can be applied to both vertical continuous type and horizontal continuous type. The granulation mechanism of continuous granulation is essentially the same for both underwater granulation and oil granulation. For example, as shown in FIG. 1, a granulation target is continuously supplied as a suspension (slurry) from a raw material supply port 4 at the tip of a granulation tank 1 of a granulator, and at the same time, the raw material supply port is supplied. 4, a predetermined amount of binder is supplied from a binder supply port 5 in the vicinity of 4, and the granulation target and the binder adhere and agglomerate in the granulation tank 1 by stirring or the like, and are further consolidated to form a granulated body. Then
The granules are discharged together with the suspension medium to the outside of the system through the discharge chamber 8 at the end of the granulation tank, and the granules are separated and collected by filtration or the like. In order to obtain a granulated product having a predetermined property in this granulation step, the amount of the raw material suspension or binder, the supply method, the rotation speed of the stirring blade, the shape and structure of the stirring blade or the granulating tank, the suspension, It is important to maintain the holdup at a predetermined level in order to perform stable granulation at the same time as setting the pH value of the suspension liquid appropriately. In particular, stable granulation in actual operation cannot be expected without proper holdup maintenance. In the submerged granulation, the retention amount of the granules due to the hold-up is 5 to 45% of the effective volume of the granulation tank (apparently), preferably 1
It is 0 to 40%, most preferably 15 to 30%.
In the submerged granulation, the granules formed in the granulation tank are immediately discharged out of the system together with the flow of the suspension medium in the tank at the same time as the granulation body is formed, and the amount of residence in the tank is extremely small. With the mechanism, it is difficult to stably obtain granules. It is necessary to carry out a granulation process in which the formed granules are confined in a tank and are discharged for a certain period of time and then discharged to the outside of the system.

Therefore, an orifice is provided at the outlet of the granulation tank to prevent the formed granulated body from freely flowing out of the system as soon as it is formed. The granules thus formed are prevented from freely flowing out by the orifice and form a layer of the granules accumulated in the vicinity of the orifice. Such an integrated layer of granules can be easily obtained in the case of batch granulation. For this reason, even in the case of continuous granulation, when starting granulation, it is common to switch the system to a continuous system after forming the accumulated layer of granules in advance by making the system a batch system by a valve operation. . The orifice according to the present invention prevents discharge of the formed granules out of the free system and forms an integrated layer, so that the orifice outlet side of the conventional orifice has a mere slope shape. Make a cut on the outlet side of the opening (for example,
Provide a notch that forms a step on the slope part,
A strong turbulent flow field is formed there to control the outflow of granules. The shape and size of the cut are not particularly limited as long as they generate a vortex on the discharge side of the orifice gap so as not to form a laminar flow.

[0010]

EXAMPLES In view of fuel cost advantage, it is common in Japan to use petroleum coke as a general industrial boiler fuel instead of "C" heavy oil. Petroleum coke is a residual solid content obtained by the decomposition reaction of high-value-added fuels such as gasoline, and has a small volatile content of around 10% by weight and is flame-retardant. Remains. This is generally referred to as petroleum coke combustion ash, and is often disposed of as industrial waste. It is possible to separate and remove ash, which is an incombustible metal oxide, from this combustion ash, selectively collect only carbon, and recycle it by applying underwater granulation using heavy oil as a binder. Has been clarified and has already been put to practical use. The examples here relate to submerged granulation in which only the carbon content is separated and collected from petroleum coke combustion ash as spherical granules having a diameter of several mm.

Properties of combustion ash of petroleum coke to be treated Ash content 12.46% weight Volatile content 7.20% weight Fixed carbon 80.34% weight Particle size composition 90% or more of 200 mesh passage Binder used JIS standard Granulator using general commercially available "C" heavy oil as shown in FIG.

Table 1 shows a comparison between the orifice gaps used, the presence or absence of orifice cuts, and whether the granulation results are acceptable or not. The structure of the gap is shown in FIG.

[Table 1]

In Table 1, when the orifice shown in FIG. 3 was used, stable continuous granulation could be performed for a long time. In the orifice having the shape shown in FIG. 4, continuous granulation was difficult because the retention amount of the granule did not reach the required level because there was no cut on the orifice outlet side. In addition, No. When the gap width was made smaller than the appropriate one as in No. 5, and the retention amount was increased, the granules having a relatively large particle size clogged or adhered to the gap, and sufficient results could not be obtained. . From these facts, it was found that it is difficult to solve the problem simply by physically reducing the gap width. A in (b) and (c) of FIG.
By making a notch as shown in the section to generate a vortex in the flow itself, which causes resistance, the retention amount is appropriately maintained, and granulation continues for a long time without trouble such as blockage. It is possible to get a body.

The granulator of the present invention can be used for forming inorganic particles such as ceramics and organic particles such as lactose, in addition to the above-mentioned carbon particles.

[0015]

[Effect] In continuous submerged liquid granulation, the structure of the orifice, which is one of the constituent elements of the granulator necessary for obtaining a granulated product stably and efficiently, can be solved by using the structure of the present invention. It is possible to carry out continuous granulation for a long time, and as a result, work efficiency and maintenance cost are extremely advantageous.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a horizontal continuous submerged granulator having an orifice.

FIG. 2 shows a plan view (a) and a sectional view (b) of an orifice in a general submerged granulator.

FIG. 3 shows a plan view (a), a cross-sectional view (b) and an enlarged cross-sectional view (c) at a portion A of the orifice according to the embodiment of the present invention.

FIG. 4 shows a plan view (a) and a cross-sectional view (b) of a non-cutting orifice of a comparative example.

[Explanation of symbols]

 1 Granulation Tank 2 Stirring Blade Rotating Shaft 3 Stirring Blade 4 Raw Material Suspension Supply Port 5 Binder Supply Port 6 Orifice 7 Orifice Gap 8 Discharge Chamber 9 Discharge Stirrer Blade 10 Discharge Pipe 11 Discharge Pipe 12 Orifice Mounting Bolt Hole 13 Stirring blade rotary shaft through hole

Front page continued (72) Inventor Masayoshi Nakamura 3-5 Kasumigaseki, Chiyoda-ku, Tokyo Showa Shell Sekiyu Co., Ltd. (72) Inventor Takamasa Kondo 2-2-8 Dojimahama, Kita-ku, Osaka, Japan Japan In Exlan Industry Co., Ltd. (72) Inventor Hideo Nakamori 2-2-8 Dojimahama, Kita-ku, Osaka City, Osaka Prefecture In Japan Exlan Industry Co., Ltd. (72) In Yasio Kubo 10-1 Kitaminato-cho, Wakamatsu-ku, Kitakyushu, Fukuoka Prefecture Incorporated company Nagata Manufacturing Co., Ltd.

Claims (3)

[Claims] 1. An in-liquid granulator, characterized in that, in an orifice provided at an outlet portion of an in-liquid granulating tank, a flow resistance region sufficient to generate a turbulent flow is provided at an outlet side of an orifice opening portion. Orifice. 2. The orifice for a submerged granulator according to claim 1, wherein the flow resistance region is a notch provided on the outlet side of the orifice opening. 3. A submerged granulation characterized by comprising a cylindrical granulation tank containing a rotary shaft equipped with a large number of stirring blades, and the orifice according to claim 1 provided on the outlet side thereof. apparatus.