JP2974695B2 - Manufacturing method of granulated coal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial application field> It is an object of the present invention to provide a method for producing granulated coal for granulating pulverized coal used for sewage and sludge treatment.

<Problems to be Solved by Conventional Techniques and Inventions> In recent years, pulverized coal has been used for purification of sewage and efficiency of sludge treatment. It is expected that the amount of pulverized coal used for sewage and sludge treatment will increase in the future for effective utilization of coal and recycling of sludge.

When transporting and storing pulverized coal, the scattered pulverized coal is contained degree 50~4000g / m ³ in air the danger of coal dust explosion occurs. In order to prevent the explosion, a method of sealing with a nonflammable gas or forming a lump to prevent dust generation is generally adopted.

Conventionally, when pulverized coal is molded, it is mainly used as a fuel or a filler, so that water and various binders are added to the powder to produce a tensile strength of 10 kgf / cm ^{2 to} 50 kgf.
Generally, it is molded firmly to about / cm ² . The present invention also belongs to a method of preventing explosion by molding and facilitating handling, but since the purpose of use is not for fuel or filler, but for sewage / sludge treatment, simply strong molding is suitable for the purpose. Absent.

When treating sewage / sludge using pulverized coal, it is necessary to disperse and suspend the sewage / sludge in the target sewage / sludge as quickly and uniformly as possible in order to sufficiently exert the function of the pulverized coal.

As a method of uniformly adding and mixing pulverized coal to sewage and sludge, a method of transporting and storing the powder as it is, a method of using it as a humidifier or a slurry, a method of humidifying or slurrying before transport, or a method of preparing a humidifier or a slurry before transport, or a binder To obtain a molded product.

However, there is a danger of dusting and explosion when transporting and storing powder as it is.To prevent this, it is costly and troublesome to seal it with noncombustible gas, and in the case of pulverized coal of 2 mm or less, the hydrophobicity of quartz There is a drawback that agglomeration occurs in water or on the surface of the water due to its properties and it is not easily suspended. Although danger prevention by humidification or slurrying is effective, it has drawbacks in that it is difficult to withdraw it from the transport storage container and that accurate weighing during use is not easy.

The pulverized coal granules formed by adding a binder overcome these disadvantages, but are hardly dispersed in water because the strength is too strong, or those using pulp waste liquid or dextrin as a binder are compared. Easy to disperse in water, but the binder dissolves in water when dispersing, so several ppm
Will increase the organic concentration by about several tens of ppm,
It goes against the purpose of sewage purification.

In view of the circumstances described above, the present invention, when transporting and storing pulverized coal, (a) prevents the danger of dust generation and explosion, and (b) enables easy and accurate handling during use such as measurement. When treating sewage and sludge using this pulverized coal, (c) the pulverized coal is easily and uniformly dispersed and suspended in the target sewage and sludge, and (d) or uniformly dispersed and dispersed in the target sewage and sludge.
An object of the present invention is to provide a method for producing granulated coal which can easily and uniformly disperse and suspend fine coal in advance for mixing.

<Means for Solving the Problems> The configuration of the present invention for achieving the above object is a pulverized coal 10
After adding and mixing 5 to 35 parts by weight of fresh water with respect to 0 parts by weight, press molding is performed, and the tensile strength is 0.2 kg f / cm ^{2 to} 0.5 kg f / cm ^2.
Characterized by obtaining a granulated product of the above.

 Hereinafter, the configuration of the present invention will be described in detail.

In the present invention, pulverized coal refers to coal having a maximum particle size of 2 mm or less, such as bituminous coal and anthracite, processed coal such as dry-distilled coal and acid-impregnated coal, and activated carbon.

The method for producing granulated coal is to add 5-35 parts by weight of fresh water to 100 parts by weight of this pulverized coal, mix them uniformly, and then apply a compression force of 100 kgf / cm ²
Granulated in the range of ~ 1000 kg f / cm ² and dried to keep the moisture content of the granulated material at 0 to 30 parts by weight, preferably about 0 to 15 parts by weight,
Tensile strength is to obtain a granule of a range of ^{0.2kg f / cm 2 ~0.5kg f /} cm 2.

Here, the tensile strength of the granulated body is defined as 0.2 to 0.5 kg f / cm ² , as shown in the following test example, 0.2 kg f / cm ²
If it is less than 10 kg, it may be powdered during transportation, storage, etc.
This is because the danger of explosion increases and a tanakaki (bridging) phenomenon occurs in the container, which makes it difficult to pull out the container.
The 0.5kg more than f / cm ² when the dispersibility in water is rapidly deteriorated, when sewage-sludge treatment, no longer easily and uniformly dispersed or suspended in water in question, the functions of the pulverized coal can be exerted Because it is gone.

To a compressive force pressing surface with 100 to 1000 f / cm ^2, such as may vary depending pulverized coal particle size distribution, and the granulated charcoal tensile strength (0.2~0.5kg f / cm ²⁾ This is because it is a compression force.

According to the method of the present invention, granules are formed by merely humidifying pulverized coal without using a simultaneous binder, and have sufficient hardness to keep the granulation due to friction and impact during transportation and storage within a safe range, and When granulated coal is used, granulated charcoal having the property of being easily and uniformly dispersed and suspended in water is obtained.

 Hereinafter, test examples showing the effects of the present invention will be described.

Test Example 1 Hardness test of granulated carbon 1 (JIS K 1474 Granular activated carbon test method 4.
Hardness test according to 7) Extruded granulated coal (φ5mm, length 5-8mm) 12 types (those with different tensile strengths) were each JIS K 1474
Test according to the hardness test method of -4.7, and shake after 30 minutes.
The mm sieve residue was determined. FIG. 1 shows the relationship between the tensile strength of each granulated coal and the tensile strength in a scatter diagram.

As shown in FIG. 1, the amount of sand helicopter caused by the shaker is
When the tensile strength of the granulated coal falls below 0.2 kg f / cm ² , it rapidly increases. Therefore, the granulated charcoal 0.2 kg f / cm ² or less in tensile strength, the percentage of granulated 2mm or less may exceed 10% target value as hardness to withstand general transport, dust, explosion There is a risk that the danger will increase, or that tanakaki development will occur in the container, and the dead stock will increase.

Test Example 2 Hardness test of granulated coal 2 (fracture test by drop impact) As in Test Example 1, 12 types of granulated coal (φ5 mm, length 5 to 8 mm) by extrusion were taken in 1 kg each, and each was smoothed. Drop the inside of an acrylic cylinder with an inner diameter of 150 mm standing on a concrete floor from a height of 1 m above the floor, sieve the entire amount of the falling object with a 2 mm mesh screen, obtain the sieve residue, and determine the total amount of the residue. The operation of dropping in the same manner and sieving with a 2 mm net screen was repeated a total of five times, and the screen residue after the five drops was determined.

FIG. 2 is a scatter diagram showing the relationship between the tensile strength of the 12 types of granulated coal and the 2 mm sieve residue after falling five times.

The tensile strength of the extruded cylindrical granulated coal was measured using a uniaxial compression tester in accordance with JIS A 1113 (Testing method for tensile strength of concrete).

As can be seen in FIG. 2, the amount dropped to 2 mm or less due to a drop impact sharply increases when the tensile strength of the granulated coal is 0.2 kgf / cm ² or less. Therefore, the tensile strength of granulated coal is 0.2kg f / cm
^If it is less than ² , the same problem as in Test Example 1 will occur.

Test Example 3 Dispersibility test of pulverized coal by humidification amount Water was added to 0,5,10,2 with 100 parts by weight of pulverized coal
Each of 0, 30, 50, and 100 parts by weight was added, and a uniform mixture was prepared. Water was added to a container 10 with a stirrer as shown in FIG. 3 so that pulverized coal became 10 kg / 100 (100 g /) on a dry basis. Weigh in humidified pulverized coal (including non-humidified and humidified granulated coal), stir for 3 minutes at a rotation speed (150 rpm) of a stirrer such that the suspended pulverized coal sufficiently spreads over the entire area of the tank, and then stir. While continuing, with the pumps 11 and 12 set in advance, 100 ml and 500 mm of the suspension water from the bottom of the container were suctioned and collected into the cylinders 13 and 14 from the point of 100 mm and 500 mm, respectively, and the whole amount was put into a constant temperature dryer at 107 ° C ± 2 ° C. The amount of dry pulverized coal was measured by evaporating water, and the amount of dispersion (g /) of pulverized coal and granulated coal (20% humidified) by humidification amount was determined.

 Table 1 shows the results.

As shown in Table 1, 0% humidification (dry pulverized coal)
Except for, there was no significant difference in the amount of dispersion.

Test Example 4 Dispersibility Test of Granulated Coal 15 parts by weight of water was added to 100 parts by weight of pulverized coal (Rekisei Charcoal), and the mixture was homogenized and granulated by changing the pressure with a compression granulator (φ15 mm, length (11.5 mm to 13.1 mm), and the tensile strength and the amount of dispersion of the granulated material (the dispersibility test method was performed according to Experimental Example 3 with the volume reduced to 1/10) were determined.

 The results are shown in Table 2 and FIGS.

Test Example 5 Relationship between Particle Size Composition, Molding Pressure, and Tensile Strength of Granulated Coal Pulverized coal (Rekisei charcoal) 100 with the particle size composition shown in Table 3 below
15 parts by weight of water was added to the parts by weight and the mixture was homogenized and granulated by applying a predetermined pressure to determine the tensile strength and the dispersibility.

 Table 3 shows the results.

As shown in Table 3, pulverized coal of 149 μm or less
When granulating under pressure at / cm ² , particles having a particle size of 44 μm or less are 55% or more, and a tensile strength of 0.2 kgf / cm ² can be secured.

In addition, even when the pulverized coal is 149 to 105 μm 100% pulverized coal, the molding pressure is 800 kg f / cm ² , and when the pulverized coal is 105 to 74 μm 100%, the molding pressure is 700 kg f / cm ² and pulverized coal 100%, 74 to 44 μm. Even in the case of, by setting the molding pressure to 600 kg f / cm ² , the tensile strength of each can be secured to 0.2 kg f / cm ² or more.

To <implementation example> pulverized coal (gravel Aosumi) 100 parts by weight, a material obtained by homogenizing the addition of water 15 parts by weight compressed molding pressure of 300 kg f / cm ^2,
Granulation was performed to obtain a granulated compact (φ15 mm, length 11.5 mm). Using the obtained granulated coal, normal storage and transport were performed, and then sewage was treated.

In this treatment, the dispersibility of the pulverized coal was good. Further, since no binder was added, there was no adverse effect on the quality of the treated water.

<Effects of the Invention> As described above in detail together with the test examples and examples, the granulated coal according to the present invention prevents the danger of dust generation and explosion, facilitates transportation and storage, and provides a tanakaki (bridging), debt Prevents stocking, improves weighing accuracy at the time of use, and also has excellent dispersibility in water, so it quickly forms a suspended state, and no special binder is added. This has the effect of not adversely affecting the performance.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are graphs showing the results of a hardness test, FIG. 3 is a configuration diagram of a container with a stirrer used in a dispersibility test, and FIGS. 4 and 5 are results of a dispersibility test. FIG. In the drawings, reference numeral 10 denotes a vessel with a stirrer, 11, 12 denotes a pump, and 13, 14 denotes a cylinder.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenkichi Sato 1-7-12 Higashi Nihombashi, Chuo-ku, Tokyo Inside Onoda Chemiko Co., Ltd. (72) Inventor Kyoichi Kiji 1-7-12 Higashi-Nihonbashi, Chuo-ku, Tokyo No. Onoda Chemiko Co., Ltd. (56) References JP-A-3-98602 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B01J 2/00-2/30 C01B 31/00 -31/36 C02F 1/28 B01J 20/00-20/34

Claims (1)

(57) [Claims] 1. To 100 parts by weight of pulverized coal, 5 to 35 parts by weight of fresh water is added and mixed, and then molded under pressure to have a tensile strength of 0.2 k.
A method for producing granulated charcoal, characterized in that a granulated compact of gf / cm ^{2 to} 0.5 kg f / cm ² is obtained.