JPS60179497A - Preparation of concentrated coal/water slurry by wet process - Google Patents

Abstract

PURPOSE:To prepare a conc, coal/water slurry efficiently with reduced amt. of grinding auxiliary, by grinding coal in water by use of a specified polyester compd. as grinding auxiliary. CONSTITUTION:Used as grinding auxiliary is a polyester compd. (deriv.) with a molecular weight of 16,000-300,000 obtained by adding alkylene oxide to about 10:90-90:10 by weight mixt. of alcohol having three active hydrogens (e.g.glycerine) and hydrocarbon [e.g. IP Solvent (in-paraffinic hydrocarbon oil produced by Idemitsu Sekiyu Kagaku Co.)]. Crushed coal, water and the grinding auxiliary are placed in a wet mill for grinding. The coal is used in such an amt. that final slurry may have a coal concn. of 60-85wt% or higher and grinding is done until at least 70% of coal particles pass a 200 mesh sieve. The grinding auxiliary is added in an amt. of about 0.03-2wt% of final coal/water slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wet process for producing a highly concentrated coal-water slurry.

In recent years, due to the depletion of oil resources, the use of coal has been reaffirmed.
Various ways of using it are being considered.

A third step is to pulverize the coal and disperse it in water to create a pumpable water slurry.

When pulverizing coal with a pulverizer, it is possible to use either a dry method or a wet method, but in the case of the dry method, the more pulverized the coal is, the more there is a risk of explosion due to coal dust, and environmental pollution. Problems occur and work efficiency decreases. On the other hand,
In the case of the wet method, not only such problems do not occur, but also the step of dispersing pulverized coal in water, which is necessary when turning coal into water slurry, can be omitted by wet pulverizing in water.

For the reasons mentioned above, it is more advantageous to wet-pulverize coal in order to produce a coal-water slurry.

Furthermore, since the coal-water slurry (1) is used as a fuel, the coal in the water slurry has a high concentration and needs to be finely pulverized to improve the combustibility of the coal.

However, in the wet grinding method, new cross sections with high surface energy always appear as the solid is ground, so this
Agglomeration occurs due to the cohesive force between the 4-carbon atoms, and pulverization is inhibited, making it extremely difficult to obtain a highly concentrated water slurry or to pulverize. The higher the concentration is, and the finer the particle size is, the more remarkable this tendency becomes, leading to a significant decrease in the pulverizing efficiency and an increase in the pulverizing power, and furthermore, the coal-water slurry becomes Eventually, the slurry becomes a gel with no fluidity, and not only is it impossible to grind it any further, but it is also impossible to take out the slurry from the mill.

Therefore, there is a need for agents to increase the grinding efficiency, ie, what should be called grinding aids.

The present inventors have developed a product in which the grinding aid is a compound containing active hydrogen in its molecule with an alkylene oxide added thereto in a high e+A1 carbon/carbohydrate slurry wet production method.
It has been discovered that the polyether compound of : can provide a /J charcoal-wood slurry which has excellent pulverization efficiency even under high concentrations and has good fluidity even when pulverized, and a patent application has already been filed. (Japanese Patent Application No. 58-31535) However, even if an attempt was made to obtain the grinding aid using the general method, the viscosity of the reaction system for obtaining a polyether compound with a high molecular weight was extremely high. The rate of addition reaction is extremely slow, and it takes an extremely long time to obtain a polyether compound of II type, which has caused problems during production. In addition, the high viscosity inhibits the uniform 4=1 addition reaction of alkylene oxide, which not only increases the amount of low molecular weight by-products other than the 1-1 polymer t'' polyether compound, but also increases the The molecular distribution of the ether compound is wide, resulting in a poor yield of the polyether compound with the suitable molecule Ji1, and there is a drawback that the use of the grinding aid 4: (addition rate) must be increased.

As a result of intensive research to improve these drawbacks, the inventors discovered a grinding aid that could reduce the addition rate and had excellent grinding efficiency even at lower rl and y = degrees, and completed the present invention. This is what led to this.

The present invention is a method of wet-pulverizing coal in water, comprising: A. Putting coarsely crushed coal, water and a grinding aid into a wet mill at the same time; B. At that time, the coal concentration in the final slurry is 60-85. Add the coal so that it has a heavy fit%, and add 20% of the coal cake.
A wet method for producing a high C degree coal-water slurry, characterized by: pulverizing until the amount of 0 mesh passing through is 70 doublets or more, and using a C6 specific pulverizing aid, or the wet method This is a method for producing a highly concentrated coal-water slurry characterized by using an antifoaming agent in the production method.

The coal used in the present invention is anthracite, bituminous coal, or
< iji blue coal, and the use of the former two is particularly preferred.

It is best to use one that has been dry-crushed in advance.

Grinding aids are unique and necessary for wet manufacturing methods.
What is the difference between the ability to strongly adsorb to the surface of new coal that continues to be generated during underwater pulverization and prevent agglomeration, and the energy during pulverization? Because it must be able to withstand force, it requires a chemical that has different performance from the chemicals used when dry-processing coal and simply mixing it with water.

The specific grinding aid used in the present invention has 3 or more active hydrogen atoms in its molecule, preferably 5 ()! An alkylene oxide is added to a mixture of a starting material (hereinafter referred to as "starting material") and a hydrocarbon oil (hereinafter referred to as "hydrocarbon oil") as a reactivity-promoting main oil (hereinafter referred to as "starting material") and an alcohol with 4 or more esters or its 7A z1 form (hereinafter referred to as starting material). !Also, it is a polyether compound having a molecular weight of ,;

Examples of starting materials for the polyether compound which is the main component of the grinding aid are as follows. Alcohols with 3 active +1 hydrogens, such as glycerin, butane]liol, hexandol, trimethylolpronochlorine, triethanolamine '9, alcohols with 4 active P1 hydrogens, such as diglycerin, penquerythritol. alcohols containing 5 or more active hydrogen atoms, such as xylitol, sorbitol, glucose, polyglycerin, sucrose, partially saponified polyvinyl acetate, partially saponified polyvinyl acetate copolymer, cellulose, starch etc. are useful, and even derivatives such as partially esterified alcohols having 4 or more -J-, active hydrogens can be used if 3 or more active hydrogens remain (I). can.

Next, hydrocarbon oils include hydrocarbon oils with a boiling point of 100°C or higher and inert to alkylene oxides, and specifically, (a) aliphatic hydrocarbon oils, such as nonane , decane, dodecane, tridecane, liquid paraffin, IP solvent (isomeric rough hydrocarbon oil, manufactured by Idemitsu Petrochemical), (b) Alicyclic hydrocarbon oil, such as decalin, P-menthane, ethylcyclohexane, ( c) Aromatic hydrocarbon oil, such as diethylbenzene,
Toluene, xylene, cumene, butylbenzene, cyclohexylbenzene, Ibsol 1. (Aromatic hydrocarbon oil, manufactured by Idemitsu Petrochemical ■), two or more selected from (d), (a), (b), and (c).
114 compounds of 1, such as kerosene, heavy oil, light oil, etc.

The blending ratio of the starting material and hydrocarbon oil is starting material/hydrocarbon oil-1O/90 to 90/10, preferably 20/10 by weight.
/80 to 80/20. If the blending ratio deviates from this ratio, the amount of by-products will increase.

Since the grinding aid of the present invention produces a polyether compound by adding hydrocarbon oil, the starting materials and the polyether compound during the reaction form a dissolved or dispersed state. Therefore, the reaction proceeds uniformly, and the production of by-products that are not useful as grinding aids can be reduced.

Compared to polyether compounds obtained without using hydrocarbon oil, the grinding aid of the present invention can reduce the amount added by 10 to 35% and has even better slurry stability. Furthermore, compared to a polyether compound fj) in which no hydrocarbon oil is used, the amount added can be reduced by 10 to 35%, and the slurry stability is even better. Also, it does not use any hydrocarbon oil.
It shows a better pulverizing effect than when a hydrocarbon oil is simply blended with a polyether compound.

Next, as alkylene oxide, ethylene oxide,
Propylene oxide, butylene oxide, etc. are used, and these may be used alone or in combination of two or more.
In the case of two or more types, the arrangement may be either a block polymerization type or a random order type, but the block polymerization type is -IIQ type. In particular, a polyether compound containing ethylene oxide as an alkylene oxide and having a content of 60 to 95 tons, 1%, preferably 80 to 95 tons of the total alkylene oxide, or a terminal hydroxyl group of the polyether compound, is subjected to various reactions. (i) Not only can a finely milled slurry with high milling efficiency and good fluidity with high milling efficiency and good fluidity at high concentrations, but also a milling medium that can be used during milling in a wet mill, It exhibits an excellent effect of preventing slurry from gelling, that is, it can absorb the impact caused by the slurry. In particular, the polyether compound or derivative thereof according to the present invention containing -4 ethylene oxide in a range of 80 to 95% by weight has an extremely excellent effect of preventing gelation of the slurry even after long-term grinding.

Also effective are derivatives obtained by subjecting the terminal hydroxyl groups of the polyether compounds listed above to various reactions. For example, we can cite the one mentioned in To.

l) Esterified products reacted with organic acids or inorganic acids.

2) Those in which the hydroxyl group is replaced with a halokene through a reaction with hydrogen halide or phosphorus halide.

3) Aldehydes and carboxylic acids produced by the butylation reaction.

4) Water is a reaction product of groups and monoisocyanates.

However, the present invention is not limited to these two examples.

The reason why the specific grinding aid of the present invention exhibits excellent effects is that its molecules are not linear but have a versatile structure with 3 or more branches, and 16,000 or more It has a large molecular weight and has many ether bonding groups of alkylene oxide, and after being strongly adsorbed to the particle surface through interaction with hydrocarbon oil, the large number of ether bonds protect the coal particles by utilizing surrounding water. Because it is well dispersed, pulverization can proceed easily even under high concentrations. In addition, it has a polymer three-dimensional structure and has an ethylene oxide content within a suitable range.

It can withstand the impact of coal particles during pulverization, prevent particles from agglomerating, and prolong gelation time. Linear types and those with small molecular weights are not suitable as auxiliaries for wet pulverization. The reason for this is understandable since it has no effect.

The addition rate of grinding aids is 0.0000000000000000000000 per final coal-water slurry.
03% to 2.0% by weight, the upper limit being determined solely for economic reasons. The method of the present invention, in which the above-mentioned coal, ice, and grinding aid are simultaneously put into a wet mill and pulverized, even if the entire amount of coal is charged so that the final slurry composition is obtained and the coal is pulverized all at once in one stage, at least two It is also possible to wet-manufacture a highly concentrated coal-water slurry by adding coal in stages or more. However, if the slurry is divided into two stages, it is easier to produce a finely pulverized slurry with a high degree of C. The grinding aid only needs to be added at the stage of charging the coal into the ball mill, and in the one-stage production method, it is added in the first stage, but in the multi-stage production method, it is added in the first stage. '' and thereafter, it is necessary to add at least a portion to the first step [I].

Next, the wet mill used in the present invention is a known wet mill having a grinding function such as a ball mill or a rod mill, and may be either a vertical type or a horizontal type.

In the present invention, the amount of grinding media such as poles and rondos packed into the wet mill is apparently 15 to 55%, preferably 20 to 40%, of the content of the upper mill, but if it is less than 15%, the coal will be crushed. Moreover, if it exceeds 55%, there will be too much grinding media and its movement distance will not be sufficient, and it will also be difficult to obtain a fluid coal-water slurry with poor grindability.

In addition, when pulverizing in one stage, the coal is fed all at once, but in multi-stage pulverizing, the coal is fed into the wet mill in the first stage.
- is 40 to 65% by weight, preferably 50% by weight in the water slurry
-60% by weight, but if the amount of coal is less than 40% by weight, the amount of coal added at a later stage will be large, resulting in poor crushability, and conversely, if the amount of coal is higher than 65% by weight, the particle size distribution will deteriorate. is difficult to achieve a high concentration, making it difficult to obtain the desired final slurry.

In any case, it is necessary to add the remaining amount of coal and continue pulverization so that the final high concentration coal-water slurry has a coal concentration of 60 to 85%.

Furthermore, in the wet manufacturing method of the highly concentrated coal-water slurry of the present invention, it is possible to prevent the pulverization of coal from progressing due to air bubbles.
1-, it is preferable to add a silicone-containing compound as an antifoaming agent. The silicone-containing compound used as an antifoaming agent is [A is hydrogen, alkylno, (or phenylno1),
1\su. n represents a number from 0 to 2,500. ] silicone oil, such as dimethyl silicone oil,
Methylhydrogen silicone oil, diphenyl silicone oil, methylphenyl silicone oil, or LE
In the silicone oil represented by the above general formula, A may be a modified silicone oil in which an organic fat, a higher alcohol, an amino group, an epoxy group, a methacryl group, etc. have been introduced into a part of A, or a halogen-containing silicone oil, e.g. fluorosilicone oil), and has a viscosity If at 25°C of o, e5 to 10,000 cst, preferably 1
000 to 100,000 cst is effective. When used, it may be added as is, but it is better to add a surfactant, inorganic powder, etc. to form an emulsion in water, which becomes finer particles and has better dispersibility, and is therefore more effective.

The amount of the silicone-containing compound as an antifoaming agent added is 0.01 to 5.0, preferably 0.03 to 2, relative to the grinding aid.
．． Even in a very small amount of 0% by weight, it exhibits a foaming effect.

The slurry produced by adding this antifoaming agent has a very low foam content, which is 2% or less based on the slurry.

Therefore, the slurry does not have its fluidity impaired by bubbles or its grindability deteriorates, and can be handled without problems.

In a one-stage manufacturing method, the entire amount of antifoaming agent is added to one stage, but in a multi-stage manufacturing method, all of the antifoaming agent is added to one of the stages! 1 (even if severely applied, l
It may be added in parts to [1] and thereafter.

If the specific grinding aid of the present invention is used and the wet grinding method described in Section 2 is followed, even if the final slurry has a very high coal concentration of 60 to 85 tons, the coal particles will coagulate among themselves. Since 11- is prevented and pulverization is easily carried out, it is possible to obtain a slurry that is finely pulverized to 70% or more of a 200-mesh pass based on XF homogeneous coal particles.

In addition, when the grinding aid related to the present invention is not used, 60
It is not possible to obtain a slurry having a double star shape or more, and it is not possible to obtain an efficiently finely pulverized slurry because wet pulverization cannot be easily performed.

Next, examples of undeveloped horns will be shown. In addition, "%" in the examples represents "weight % J.

Example 1 Eighteen types of coal-water slurries were manufactured using Datong coal, which is a type of bituminous coal, and Bongei coal, which is a type of anthracite, using the following three methods.

The coal used was coarsely ground to a particle size of 2 tm using a dry mill. The grinding aids used are shown in Table 1.

Method A: The entire amount of the grinding aid, coal, and water, or further the entire amount of the antifoaming agent, was added to a ball mill and pulverized for 70 minutes in a one-stage method.

Method B: Grinding aid, predetermined amount of coal, and total amount of water, or
Furthermore, the entire amount of antifoaming agent was added to the ball mill, and the first
The coal was pulverized for 40 minutes in the first stage, and then an additional φ of coal was introduced into the ball mill, and the second stage pulverization was performed for 30 minutes.

Method C: Grinding aid, predetermined amount of coal, and total amount of water, or
Furthermore, the entire amount of antifoaming agent was added to the Rock + S mill, and 4
The first stage of pulverization was carried out for 0 minutes, and then an additional J+5- of coal was added to the rod mill, and the first stage of pulverization was carried out for 30 minutes [j11].

Details of each manufacturing condition and properties of the final slurry manufactured,
The stability evaluation results are shown in Table 2. The final slurry produced is shown below. Depends on the test method.

After production, the slurry was taken out from the mill, its fluidity was measured, and the viscosity of the slurry was measured at 25°C using a B-type viscometer.

In addition, the IF value of crushability is determined by sifting the crushed coal-water slurry (stone) R through a 200-mesh sieve.
Passed 200 meters! 11 (%) went there. Pass::j
, (%) indicates good crushability. Further, the stability of the obtained slurry was evaluated by # penetration test shown in the first order.

That is, the prepared coal-water slurry was placed in a measuring cylinder with an inner diameter of 5.5 cm and a height of 20 cm and left to stand at a height of 18 cm from the bottom, and a center guide hole was drilled at the top of the cylinder after 3 o] and 451 J. Through the hole, a stainless steel rod with a tip of 5 fl 1 m in diameter (total weight of 50 g) was dropped vertically from the surface of the coal slurry, and the time required for the tip to reach the bottom of the cylinder was measured. The shorter this time is, the lower the sedimentation pressure of the pulverized coal is and the more stable it is.

As is clear from the test examples in Table 2, according to the present invention, coal pulverized in a wet mill, water, and a pulverizing aid, or an extinguisher is added simultaneously to these to produce a coal slurry by a wet manufacturing method. Therefore, regardless of coal type, coal-made 1
Negative 70-80% and 200 mesh pass amount 81.0
~84.5% finely milled viscosity 700~+900cp
A slurry with good fluidity was obtained and could be easily pulverized even under high Q degree. Further, regarding the slurry production conditions, a finely ground slurry with a higher concentration was obtained in the two-stage wet production method than in the one-stage production method.

Furthermore, when the antifoaming agent was added, a finely ground slurry with a higher concentration was obtained than when the antifoaming agent was not added. Furthermore, the rod penetration time of the slurry obtained by the method of the present invention is as short as 3.0 to 8.5 seconds even after being allowed to stand for 45 days, and the secondary effect is that a homogeneous coal slurry with excellent long-term stability can be obtained. was also recognized.

In addition, if a grinding aid is not added or if a low-molecular-weight polyether compound that does not meet the essential conditions of the present invention is used as a grinding aid, sufficient grinding cannot be achieved even at a coal concentration of 60 to 66%. inferior in sex. Further, the slurry did not flow at all, and further pulverization was impossible, and a finely pulverized coal slurry could not be obtained.

Example 2 According to the same slurry manufacturing method as in Example 1, using the grinding aid shown in Table 1, wet grinding was carried out until the slurry gelled and the fluidity of the slurry disappeared,
The pulverization time (gelation time) was measured.

The longer the 111j-duration, the better the energy resistance or impact resistance of the grinding aid. Details of slurry production conditions and test results are shown in Table 3.

As is clear from the test examples in Table 3, when coal, water, a grinding aid, and an antifoaming agent are simultaneously put into a wet mill according to the present invention to produce a coal slurry, the total alkylene oxide of the grinding aid of the present invention is Ethylene oxide content is 73%
When the ethylene oxide content is 82-94%, the gelation time is 140 minutes.
It was a minute long. In other words, this drug has a long kelization time;
It had strong impact resistance and excellent anti-gelling effect. Also,
When no antifoaming agent is added, the gelation time is 125 minutes with a grinding aid with an ethylene oxide content of 65%, and the gelation time is 170 minutes or 180 minutes with a grinding aid with an ethylene oxide content of 85% or 80%. The gelation time was shorter than when an antifoaming agent was added.

In addition, in the case where no grinding aid is added or in the case of a comparative example in which a low molecular weight polyether compound that does not meet the essential conditions of the present invention is used as a grinding aid, the stone r&g 5 degree is 60 to 66%.
However, it did not become a slurry, and the gelation time was 15 to 2
A gelatinized state was produced in a short time of 0 minutes.

Example 3 509, 30% of the rigid balls were inserted into a continuous wet ball mill, and the test Nos. 2-1 to 2 were shown in Table 2 of Example 1. -5.2-8~2-1
2.2-■ Crushed coal of 6 to 2-18, manufacturing method, crushing aid, antifoaming agent 1. The slurry was manufactured under the same slurry manufacturing conditions as rJiRC, with the amount of slurry being adjusted such that the residence time of the final slurry in the mill was 70 minutes. As a result, test No.
In the continuous production method carried out under the same conditions as 2-1 to 2-5.
In other cases, the slurry gelled and was not discharged from the mill. In other words, if the wet pulverization method is followed, it is possible to produce a finely pulverized high-concentration slurry even with a continuous pulverization method.

Furthermore, test No. 2-1 = 2-5.2-8 to 2-1
Continuous wet pulverization was carried out under the same conditions as in Example 2, except that the amount of slurry produced was reduced to 50% of that of all Examples. At this time, the residence time of the final slurry in the mill was 140 minutes.

As a result, 200 meshes were passed, l
A finely pulverized slurry of 85 to 88% with good fluidity was obtained; however, other than that, the slurry gelled and was not discharged from the mill. In other words, when the grinding aid of the present invention with an ethylene oxide content of 82 to 84% is used according to the wet grinding method of the present invention, the anti-gelation effect is even more excellent, resulting in good fluidity even when the residence time in the mill is long. Continuous production of slurry was carried out in 11 batches.

Procedural amendment 1. Description of the case 1982 Patent Application No. 034740 2 Title of the invention Wet manufacturing method for highly concentrated coal-water slurry 3 Person making the amendment Relationship to the case Patent applicant 55 Higashikubo-cho, Nishi-shichi-jo, Dokyo-ku, Kyoto City Voluntary action Amendment 7: Correct ``Aromatic genus j to 1 aromatic group'' on page 11, line 2 of the description of contents of the amendment.

Page 12, lines 1-4 “Also, hydrocarbon oil QΦ...
...even better. Delete J.

Page 21, line 2, ``Show. Test J'' is corrected to ``Show test j.

On page 25, line 18, ``All Examples j is corrected to ``Previous Example J.''

In the column of type of antifoaming agent in Table 2 on page 28, test No.
2-41bj to 1r-j, test No. 2-51'-j
Correct them to 1m'b j.

that's all

Claims (1)

[Claims] (1) A method for wet-pulverizing coal in water. A. Coarsely crushed coal, wood, and crushing aids in a wet mill.
B, its 11+i, the stone IAC degree in the final slurry is 60~85-m? Coal is added so that the amount of coal particles passing through 200 mensch is 70% by weight or more.
-, and the C9 grinding aid uses an alcohol or a derivative thereof having 3 or more, preferably 5 or more active hydrogens in the molecule as a starting material (hereinafter referred to as starting material), and improves the reactivity. A molecule obtained by adding alkylene oxide to a mixture containing hydrocarbon oil (hereinafter referred to as hydrocarbon oil) as an oil.
tl l El 000 to 300,000, or a terminal hydroxyl group of the polyether compound (
When preparing the wet grinding aid (2) for highly concentrated coal-water slurry (11), which is characterized by containing as an essential component derivatives obtained by various reactions of
Blending ratio (A)/(13
) is from 10/90 to 90/10, preferably from 20/80 to 80/'20
j R' + Wet method for producing highly concentrated coal-water slurry according to claim (1). (3) The grinding aid contains ethylene oxide as an alkylene oxide, and its content is 6% of the total alkylene oxide.
0 to 85% by weight, preferably 80 to 95% by weight
A wet method for producing a highly concentrated coal-water slurry according to claim (1) or (2). (4) High concentration A1) according to any one of claims (1) to (3), wherein the coal is anthracite, a-blue coal, sub-bituminous coal, preferably anthracite, or H-blue coal. R-Wet manufacturing method of water slurry. (5) A) A method of wet pulverizing coal in water, A. Put the coarsely pulverized coal, water and a pulverizing agent into a wet mill at the same time, put an antifoaming agent in a colander, and B. At that time, Add icocoal so that the coal concentration in the slurry is 6 to 85% by weight, and grind until the amount of coal particles passing through 200 meshes is 70% by weight or more. Fullylene oxide is added to a starting material of an alcohol or a derivative thereof having at least 3, preferably 5 or more active hydrogen atoms, and a hydrocarbon oil as a reactive oil. plus f
Containing as an essential component a polyether compound having a molecular weight of lJ + eooo to 300,000 or a derivative obtained by various reactions of the terminal hydroxyl group of the polyetherified n product;
and a defoaming agent containing a silicone-containing compound as an essential component. (6) High Q degree coal according to claim tJS(,5), wherein the antifoaming agent is 0.01 to 5.0% by weight, preferably 0.03 to 2.0% by weight based on the grinding aid. - water slurry) Lee's wet manufacturing method.