JPS63297498A - Additive of long life for high-concentration coal-water slurry - Google Patents

Abstract

PURPOSE:To obtain the titled additive giving coal-water slurry which can be transmitted by pumping and is directly usable as a boiler fuel, by sulfonation of a mixture of (alkyl) naphthalene, anthracene and diphenyl, etc. followed by condensation with formaldehyde. CONSTITUTION:The objective additive consisting of a compound (or its salt) with an average condensation degree of 10-500 (pref. 35-100) can be obtained by sulfonation of a mixture comprising (A) 40-7wt.% of naphthalene, (B) 10-40wt.% of an alkylnaphthalene, (C) 1-20wt.% of anthracene and (D) 1-15wt.% of diphenyl followed by condensation with formaldehyde.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is an additive for long-life, high-concentration coal-water slurry, more specifically, it can be transported by pump and can be used as is as boiler fuel in power plants, etc. The present invention relates to a long-life additive for highly concentrated coal-water slurry.

(Prior Art) In recent years, due to the depletion of petroleum resources and soaring prices, the use of coal has been rediscovered, and various methods of its use are being studied.

However, since coal is solid and cannot be transported by pump, a water slurry of pulverized coal is attracting attention because it can be transported by pump and can be directly burned as boiler fuel in power plants and the like.

However, if a slurry of coal and water is produced without using chemicals, the viscosity of the slurry becomes high, making it impossible to produce a water slurry with a high coal concentration.

Lower coal concentrations reduce transportation efficiency and require a dehydration step before combustion, which increases costs.

Therefore, research is being conducted on thinning agents that reduce the viscosity of highly concentrated coal-water slurries.

For example, JP-A-56-21838 and JP-A-5B-138
No. H5 states that formalin condensates of naphthalenesulfonic acid or salts thereof having a degree of condensation of 1.2 to 30 are useful for this purpose.

However, the formalin condensate of naphthalene sulfonic acid or its salt described in these prior art does not have a sufficient dispersion effect, and when the degree of coal production exceeds 60-2, giratancy occurs, making pump transportation difficult. Understood.

In addition, there were many problems in that the produced slurry changed over time, that is, the viscosity increased over time, and sedimentation and consolidation occurred.

More specifically, naphthalene sulfonic acid formalin condensates (degree of condensation 4) are described in the prior art. However, the stability of the slurry has not been evaluated, and the coal concentration is less than 60ffiffi%.
It was extremely inappropriate.

In fact, these additives had no effect at all, and after one month, the viscosity of the slurry increased to nearly 10,000 cps.

It was not possible to create a slurry with self-flowing properties, and it was not possible to obtain a slurry that maintained its fluidity immediately after production for a long period of time and was free from sedimentation.

(Problems to be Solved by the Invention) An object of the present invention is to solve the above-mentioned problems and provide an additive for highly concentrated coal-water slurry that has low viscosity, long life, and self-flowing properties. It is something to do.

(Means for solving the problem) An additive added when producing a highly concentrated coal-water slurry by crushing coal in the presence of water, the additive containing 40 to 70% by weight of naphthalene. , alkylnaphthalene 10-40fil1%.

A long-life, high-concentration coal characterized by being a compound or a salt thereof obtained by sulfonating a mixture containing 1 to 20 fi% of anthracene and 1 to 15 fi of diphenyl as essential components and then condensing it with formaldehyde. It is an additive for water slurry.

Used as an additive in the present invention. Such compounds or salts thereof include naphthalene and furkylnaphthalene; for example, mixtures containing ethylnaphthalene, propylnaphthalene, butylnaphthalene, etc., and anthracene and diphenyl as essential components.

Examples include sulfonic acid formaldehyde condensates or salts thereof obtained by sulfonating and then condensing with formaldehyde by a known method.

The amount of the above mixture must be 4m, and the mixing ratio must be 40 to 70% by weight of naphthalene, 10 to 40% by weight of alkylnaphthalene, 1 to 20% by weight of anthracene, and 1 to 1S weight% of diphenyl. It is.

If any of the four components is missing in the mixture, the resulting additive will have insufficient dispersing power, and as a result, a highly concentrated slurry will not be obtained.

Similarly, if the mixing ratio of the four components is outside the above range, a slurry with long life and self-flowing properties cannot be obtained even if the resulting additives are blended.

The compound or salt thereof obtained by sulfonating these mixtures and condensing them with formaldehyde has an average degree of condensation of lθ
-500 preferably 35-100.

If the average degree of condensation is less than 10, the resulting additive will have insufficient dispersing power, and as a result, a highly concentrated slurry will not be obtained.

Furthermore, if the average degree of condensation exceeds 500, the viscosity increases and it is impossible to obtain an additive with fluidity.

The average degree of condensation of the above compound or its salt is determined by GPC analysis! It is determined from the 1 weight average molecular weight.

The GPC measurement conditions mentioned here are as follows.

Power 5: TSK GEL G-4000SW+G-
3000SW ÷ Guard Column (Toyo Soda) Column size: 5 yen φ x 600 intestinal layer x 2 wood column temperature: room temperature Mobile phase Niacetonitrile/0.05M sodium acetate 40/60 Flow rate: 0.85m! L/win Detector: Ultraviolet absorption detector Wavelength 254 nm Standard material: Sodium polystyrene sulfonate Molecular weight 1800~
85000 (Pressure Chemical Go,
) Salts of the above compounds include alkali metals such as sodium and potassium, or magnesium.

Examples include alkaline earth metals such as calcium, ammonia, and amines.

Next, the amount of additive used is 0 for the coal-water slurry.
．． 01-5.0% by weight, preferably 0.03-2.0!
i amount%, and excellent effects are exhibited at this amount.

Generally, if no additive is used, a coal-water slurry loses fluidity when the coal concentration is around 50% by weight, but if the additive of the present invention is used, the viscosity decreases significantly, so the coal concentration is 60% by weight or more. In particular, the slurry has fluidity even at 64% by weight or more, and there is no visible change in the slurry over time.Even if it is left standing for one month, no coal agglomeration or sedimentation occurs, and the pump can be pumped from inside the tank. It can be easily dispensed by.

Furthermore, in the case of a coal-water slurry using cleaner coal, the coal concentration increases by several points.

Coal-water slurry produced using additives is produced by a wet process, and specifically, coal, water, and additives are added to a pulverizer and the slurry is pulverized.

The additives at this time may be added all at once at the beginning, or may be added in multiple stages in the middle.

Alternatively, a method may be used in which coal and water are once put into a pulverizer at a low concentration to produce a low concentration slurry, and then the slurry is dehydrated and additives are added thereto and mixed.

However, the present invention is not limited to these specific production methods, and is intended for all production methods that include the step of crushing coal in water. Coal used in the production of coal-water slurry is anthracite 1M blue coal, subbituminous coal,
Any kind of coal may be used, such as lignite or cleaned coal.

Cleaned coal is coal from which inorganic substances such as ash and sulfur have been removed.

Methods for cleaning coal include, for example, a heavy liquid separation method, an 0-mole aggregation method (hereinafter referred to as an OA method), a flotation method, and the like. However, methods other than these may be used and are not particularly limited.

If such lean coal is used, the effect of the additive of the present invention is significantly superior to that of uncleaned coal, and a coal-water slurry with several points higher concentration can be obtained.

Furthermore, when using cleaner coal, in addition to this effect, boiler corrosion during combustion is suppressed, and ash removal equipment and
It has great benefits such as reducing the burden on desulfurization equipment.

Further, the particle size of the coal used may be any particle size, but since the pulverized coal currently burned in thermal power plants is 200 mesh pass 70% by weight or more, this particle size is a standard.

However, the additive of the present invention is not affected by particle size, and exhibits excellent effects for any particle size.

(Effect of the invention) The additives obtained according to the present invention are excellent in the effect of stably dispersing coal in water, and when added to a coal-water slurry, the slurry changes over time and after being left standing for one month. A self-flowing highly concentrated coal-water slurry with a low viscosity and a long life, which can be easily pumped out from the tank with no agglomeration or sedimentation of the coal, is obtained. Considering the reason why the additive obtained according to the present invention has excellent performance as described above, the additive of the present invention has a large steric coverage due to a large degree of condensation.
It is thought that when acting at the interface between coal and water, the larger the coverage, the more it prevents the coal particles from agglomerating and improves the dispersion force.This also prevents the coal from coagulating and settling, so the slurry It is considered that almost no change occurs over time.

Furthermore, since the starting material mixture contains anthracene and diphenyl, it increases adsorption to coal particles and maintains the neo-footwork structure of coal particles for a long time, resulting in long-life self-flowing properties (low It is thought that a highly concentrated coal-water slurry (viscosity) can be obtained.

On the other hand, when conventional additives are used, there are problems with the stability of the slurry, such as an increase in viscosity over time and the generation of aggregates.
No water slurry is obtained.

(Example) Examples of the present invention are shown below.

In the examples, "r%" represents r% by weight.

Example 1 A coal-water slurry was prepared using bituminous coal and the additives shown in Table 1 using the following two methods.

The coal used was pulverized to a particle size of approximately 2+i layers using a dry mill.

Method (A): Coarsely crushed coal (approximately 3+wm or less), water, and additives were placed in a ball mill in predetermined amounts and pulverized until the coal particle size reached 80% of the amount passing through 200 mesh.

Method (B): A predetermined amount of coarsely crushed coal (approximately 3 layers or less) and water were put into a ball mill to produce a slurry with a coal grain size of 40% and a coal particle size of 80% passing through 200 meshes.

After this, it is dehydrated to a specified concentration and then Add additives and stir with a lab body spar. A slurry was obtained by stirring.

The produced slurry was evaluated by the test method shown below.

1) Slurry viscosity: Haake rotational viscometer at 25°C, The measurement was performed at a shear speed of 100 seconds.

2) Slurry life: Measured using the pot method.

That is, the produced slurry was placed in a 250-inch wide-mouth bottle and allowed to stand for one month, and then drained from the polyethylene bottle by gravity and passed through a 5-layer sieve.

At this time, the amount of slurry remaining in the plastic bottle and the amount of slurry on the 5-inch sieve was measured as the amount of agglomeration, and the aggregation rate (a) relative to the total slurry (
%) was calculated.

The viscosity of the slurry was also measured after it was left standing for one month.

Slurry with a smaller amount of agglomeration and a viscosity that is unchanged from immediately after production is a better slurry with a longer lifespan.

The evaluation results are shown in Table 2.

According to the invention as evident from Table 2.

By wet manufacturing coal-water slurry using method (A) or method CB), the viscosity is 1000 cp with a coal content of 77%.
A coal-water slurry with good fluidity was obtained.

Further, even after the slurry was allowed to stand for one month, there were almost no aggregates and the viscosity of the slurry hardly increased, making it possible to obtain a highly concentrated coal-water slurry with a long life.

On the other hand, in the case of a comparative example that does not meet the essential requirements of the present invention, the naphthalene sulfonic acid formaldehyde condensate with a low degree of condensation has a viscosity of 1300 to 1400 cp at a stone YR concentration of 60%.
Although the fluidity was good, the viscosity after standing for one month was 1000.
It was approximately 0 cp, had extremely poor fluidity, and had a very large amount of agglomeration, making it unsuitable for discharging from a tank or the like.

Example 2 The same coal as in Example 1 was used, and the additives shown in Table 1 were used.

The method for producing coal-water slurry is as follows:
It was carried out using the following two methods.

Method (C): A predetermined amount of coal, water, and additives cleaned by the OA method were put into a ball mill and pulverized until the coal particle size reached 80% of the amount passing through 200 mesh.

Method (D): A predetermined amount of coarse pulverized coal (approximately 3 cm or less) and water were put into a ball mill to produce a slurry with a coal particle size of 200 mesh passing through 80% at a per stone mW degree of 15%.

This slurry is deashed by flotation method and Dehydrated to a constant concentration.

Add additives to it and create a lab body spar. A slurry was obtained by stirring.

The final slurry produced was rated = f according to the same test method as in Example 1.

The evaluation results are shown in Table 3.

As is clear from Table 3, according to the present invention, by wet-producing a coal-water slurry using cleaned coal by method (C) or method (D), the viscosity is 1000 cp at a coal concentration of 80%.
The following coal-water slurry with good fluidity was obtained.

Furthermore, even after the slurry was allowed to stand for one month, there were almost no aggregates and the viscosity of the slurry hardly increased, making it possible to obtain a highly concentrated coal-water slurry with a long life.

On the other hand, the naphthalene sulfone formaldehyde condensate having a small degree of condensation shown in the comparative example has already a slurry viscosity of 9000 cp or more at a coal content of 67%, and has poor fluidity.

Claims (4)

[Claims] (1) An additive added when producing a highly concentrated coal-water slurry by pulverizing coal in the presence of water, the additive comprising 40 to 70% by weight of naphthalene and 10 to 40% by weight of alkylnaphthalene. %, a long-life, high-concentration compound obtained by sulfonating a mixture containing 1 to 20% by weight of anthracene and 1 to 15% by weight of diphenyl as essential components, and then condensing it with formaldehyde, or a salt thereof. Additive for coal-water slurry. (2) The additive for long-life, high-concentration coal-water slurry according to claim (1), wherein the compound obtained by condensation or a salt thereof has an average degree of condensation of 10 to 500, preferably 35 to 100. (3) Highly concentrated coal-water slurry has a coal concentration of 60% by weight
The additive for long-life, high-concentration coal-water slurry according to claim 1 or 2, wherein the content is preferably 64% by weight or more. (4) The additive for long-life, high-concentration coal-water slurry according to claim 1, (2), or (3), wherein the coal is cleaned coal.