JPS63258989A - Additive for high-concentration coal-water slurry having long life - Google Patents

Abstract

PURPOSE:To obtain the titled additive for a slurry transportable with pump and directly usable as a fuel for boiler of power plant, by using naphthalenesulfonic acid, etc., and polyethylene polyamine fatty acid amide compound as essential components. CONSTITUTION:The objective additive contains (A) an (alkyl)naphthalenesulfonic acid formaldehyde condensate (salt) having an average polymerization degree of 10-500 (preferably 35-100) and (B) a polyethylene polyamine fatty acid amide compound at a ratio (A/B) of about 50/50-98/2. The additive is applicable to a wet-pulverized slurry having a coal concentration of >=60wt.% (preferably >=64wt.%).

Description

[Detailed description of the invention] Industrial emperor and beans! The present invention is an additive for coal-water slurry produced by a wet method, and more specifically, an additive for obtaining a long-life, highly concentrated coal-water slurry that can be transported by pump and used as boiler fuel in power plants, etc. Regarding drugs.

In recent years, due to the depletion of oil resources and soaring prices, the use of coal has been rediscovered, and various ways of using it are being considered. However, since coal is solid and cannot be transported by pump, a water slurry of pulverized coal that can be transported by pump and can be directly burned as boiler fuel in power plants, etc. is attracting attention. 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.

JP-A-56-21636 and JP-A-56-136665 describe that a formalin condensate of naphthalenesulfonic acid or a salt thereof having a degree of condensation of 1.2 to 30 is useful for this purpose. However, it has been found that the formalin condensate of naphthalene sulfonic acid or its salt proposed in the prior art does not have a sufficient dispersion effect, and that giratancy occurs when the coal concentration exceeds 60%, making pumping difficult. Ta. 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. Furthermore, in JP-A-58-17195 and JP-A-58-122991, a nonionic surfactant and naphthalene sulfonate formaldehyde condensate (1,2-3
0 nuclear body) is described. More specifically, JP-A-58-17195 discloses (a) naphthalene sulfonic acid formalin condensate (2 to 10 nuclei) and (bl alkylene oxide (ethylene oxide: 95 to 40 mol%, and propylene oxide or butylene oxide). (a):(b)
It is described that they are used in combination at a ratio of =50-5:50-95. Furthermore, JP-A-58-122991 discloses (a) naphthalene sulfonic acid formalin condensate (1,
The combination use of a compound obtained by adding 4 to 800 moles of ethylene oxide and/or propylene oxide to a compound having 2 to 30 nuclear bodies) and 1 or more bl active hydrogen atoms is described. However, in these methods, the stability of the slurry was simply evaluated using a rod penetration test, which was extremely inappropriate when considering actual scale. In other words, even if the rod penetrates smoothly after one month of standing, the slurry may have increased viscosity or formed soft packs, causing problems in discharging from the storage tank or stationary tank, or causing combustion problems. There were problems such as the spray nozzle becoming clogged. In fact, these additives had no effect at all, and the viscosity of the slurry increased to nearly 10,000 cps after one month, making it impossible to create a slurry with self-flowing properties and maintaining the fluidity immediately after production for a long period of time. A slurry without sedimentation could not be obtained.

Therefore, it is an object of the present invention to solve these problems and provide an additive for highly concentrated coal-water slurries that has low viscosity and long-life self-flowing properties when the slurry is evaluated by the pot method. .

In other words, the present invention provides an additive that is added when producing a highly concentrated coal-water slurry by pulverizing coal in the presence of water, comprising (a) naphthalene sulfonic acid and/or alkylnaphthalene; Provided is a long-life, high-concentration coal-water slurry additive characterized by containing a formaldehyde condensate of sulfonic acid or a salt thereof, and (b) a polyethylene polyamine fatty acid amide compound.

Examples of the formaldehyde condensation product or salt thereof of naphthalene sulfonic acid and/or alkylnaphthalene sulfonic acid as component (a) of the additive of the present invention include naphthalene, methylnaphthalene, ethylnaphthalene, propylnaphthalene, butylnaphthalene, or mixtures thereof. Formaldehyde condensates of sulfonated products, or salts thereof.

The average degree of condensation of these formaldehyde condensates of sulfonic acids is 10 to 500. Preferably it is 35-100.

If the average degree of condensation is lower than this range, the dispersion force will be insufficient and a highly concentrated slurry cannot be obtained. If the average degree of condensation is too high, the viscosity will increase, making it impossible to obtain an additive with fluidity.

Examples of the salts of formaldehyde condensates of these sulfonic acids include alkali metal salts such as sodium salts and potassium salts, alkaline earth metal salts such as calcium salts and magnesium salts, ammonium salts, and amine salts.

Examples of the polyethylene polyamine fatty acid amide compound as component (b) of the additive of the present invention include compounds obtained by reacting polyethylene polyamine and fatty acid. The raw material polyamine is 82N-+cHzcH2NII7rrH where n is 2
~15. Preferably it is 3 to IO. In addition, fatty acids have 6 to 25 carbon atoms. Preferably 8 to 19, for example, caproic acid, capric acid, lauric acid, pentadecanoic acid,
Examples include margaric acid, stearic acid, coconut fatty acid, beef tallow fatty acid, and the like.

When these polyethylene polyamines and fatty acids are reacted, they are reacted in a nitrogen gas stream so that the molecule contains 1 to 3 amide groups, preferably 1 to 2 amide groups.

Examples of the additives of the present invention include those containing the above-mentioned (al component) and the above-mentioned (bl component).

(The blending ratio of the al component and the component (b) (al/(b) is preferably 50150 to 98/2 by weight, and by blending the polyethylene polyamine fatty acid amide compound of the component (b), the product has a low viscosity and a long life. A highly concentrated coal-water slurry can be produced.

If the amount of component (b) is too large, the slurry will gel and no effect will be obtained, so it is very important to maintain the above blending ratio.

The average degree of condensation of the fat component of the additive of the present invention is Gpc
Determined from the weight average molecular weight by analysis. G here
The PC measurement conditions are as follows.

Column: TSK GIEL G-4000SW +
G-3000S + guard column (Toyo Soda) Column size Near, 5 Dragon φX 600DX 2 columns Temperature: Room temperature Mobile phase: Acetonitrile 10.05M sodium acetate = 40/60 Flow rate: 0.85 m/win Detector: Ultraviolet absorption detection Instrument Wavelength 254nm Standard material: Sodium polystyrene sulfonate.

Molecular weight 1600-65000 (PressureC
chemical Co.) The coals used in the coal-water slurry include anthracite, bituminous coal,
Any type of coal may be used, such as sub-bituminous coal, lignite, or cleaned versions thereof. Also, the particle size of the coal in the water slurry may be any particle size, but the pulverized coal currently burned in thermal power plants is 200 mesh pass 70
% 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.

Cleaned coal is coal from which inorganic substances such as ash and sulfur have been removed. Methods for cleaning coal include, for example, heavy liquid separation method, Oil Ag
There are methods such as glomeration method (hereinafter referred to as OA method) and flotation method. However, methods other than these may also be used and are not particularly limited.

Regarding the OA method, after dry or wet pulverization of coal, a water slurry is prepared and an appropriate amount of oil is added, or
After coating coal with oil in advance, a water slurry is prepared and stirred to make use of the difference in wettability of the organic and inorganic components of the coal to oil and water, thereby applying oil that selectively wets the organic components of the coal. It is used as a binder to cause coal organic content to coagulate. On the other hand, since inorganic substances have a weak affinity with oil, they are liberated in water, so this method can simultaneously remove inorganic substances by separating water from coagulated coal. The coal concentration in the coal-water slurry of the OA method is usually 10 to 50%.

The oil used in the OA method is generally crude oil or various fractions obtained from crude oil, such as kerosene, light oil, A heavy oil, B heavy oil, C heavy oil, tar or shale oil, ethylene cracked residue, or various blended oils. The oils used are mineral oils such as lubricating oils and cleaning oils. Although benzene, toluene, xylene, animal and vegetable oils, etc. can also be used, heavy oils such as C heavy oil and tar residue oil are particularly preferred because they are inexpensive. It is generally sufficient to use this oil in an amount of 30% or less of the coal in the coal-water slurry to be treated for mineral removal.

The flotation coal washing method is an existing coal washing method in which a very small amount of oil is added to the pulverized coal-water slurry and stirred to create foam.
Generate floss. Similar to the OA method, in this method, the organic components of the coal adhere to the froth oil film, but the inorganic components are liberated in the water.
This is a method that can separate coal organic components.

The oils used in the flotation method are turpine oil, tar, A heavy oil, C heavy oil, light oil, and kerosene.

Generally, several tens of percent or more of inorganic substances are removed from coal by the above method.

When using coal that has been cleaned in this way, the effect of the additive of the present invention is significantly superior to that of coal that has not been cleaned, and a coal-water slurry that is several points higher in concentration can be obtained. Furthermore, when cleaned coal is used, in addition to this effect, boiler corrosion during combustion is suppressed, and the burden on ash removal equipment and sulfur removal equipment is reduced.

The coal-water slurry produced using the additive of the present invention is produced by a wet method, and specifically, coal, water, and the additive are added to a pulverizer, and the slurry is produced while pulverizing the coal. At this time, the additives may be added all at once at the beginning, or may be added in multiple stages in the middle. Also, once low concentration coal and water are put into a pulverizer to produce a low concentration slurry,
A method in which additives are added to the dehydrated mixture and mixed is also useful. However, the present invention is not limited to these specific manufacturing methods, but is directed to all manufacturing methods that include the step of pulverizing coal in water.

The amount of the additive of the present invention used is 0.01 to 5.0% by weight, preferably 0.03 to 2.0% by weight, based on the coal-water slurry.
It is 0% by weight, and this amount exhibits excellent effects. The fluidity limit of a coal-water slurry varies depending on the type and particle size of the coal, but generally, if no additives are used, the fluidity will disappear when the coal concentration is around 50% by mass, but with the additive of the present invention, Since the viscosity is significantly reduced, it has fluidity even when the coal concentration is 60% by weight or more, particularly 64% by weight or more. Furthermore, when cleaned coal is used, the coal concentration increases by several points.

In addition, there was no visible change in the slurry over time, and even after it was left standing for a month, no coal agglomeration or sedimentation occurred, and it had self-flowing properties that allowed it to be easily pumped out of the tank. A highly concentrated coal-water slurry with a long life can be produced.

A conventional formaldehyde condensate of a naphthalene sulfonate having a low degree of condensation (degree of condensation of 30 or less) alone has a completely poor dispersion effect, and a highly concentrated coal-water slurry cannot be obtained.

Also, JP-A-58-17195 and JP-A No. 58-122991
For example, a formaldehyde condensate of naphthalene sulfonate with a low degree of condensation (1,2 to 30 nuclei) and a nonylphenol propylene oxide/ethylene oxide adduct (30/70) (M3300) or glycerol propylene oxide 5 Even when the Roll adduct was used in combination, an increase in the viscosity of the slurry over time and the generation of aggregates were observed, and a highly concentrated coal-water slurry that maintained fluidity for a long period of time immediately after production could not be obtained.

That is, like the formaldehyde condensate of naphthalene sulfonate with a high degree of condensation as component (a), which is unique and has been researched and developed by the present inventor, it is unique (bl
It has been discovered that excellent effects can be exhibited only when the component polyethylene polyamine fatty acid amide compound is used in a very limited combination.

Considering the reason why the performance is so excellent, the additive of the present invention has a high degree of condensation of the formaldehyde condensate of naphthalene sulfonate (component (a)), so the steric masking is large, and the additive has a high degree of condensation. This is because when acting at the interface between coal particles and water, the larger the coverage, the more the coal particles are prevented from aggregating and the dispersion power is improved. Moreover, since this prevents the coal from coagulating and settling, it is thought that almost no change in the slurry occurs over time. Also (b
) By using the component polyethylene polyamine fatty acid amide compound in combination, the naphthalene sulfonic acid formaldehyde condensate adsorbed on the coal particles is prevented from peeling off, and the polyethylene polyamine is adsorbed on the coal particles, making the adsorption layer thicker. This makes it possible to maintain the network structure of coal particles for a long period of time, making it possible to obtain a long-life, low-viscosity, highly concentrated coal-water slurry.

Examples and comparative examples of the present invention are shown below. These percentages are by weight.

Example 1 Coal-water slurries were produced using bituminous coal and the additives shown in Table 1 using the following two methods.

The coal used was coarsely ground to a particle size of approximately 2 grains using a dry mill.

Method (A): A predetermined amount of coarsely crushed coal (approximately 31 mm or less), water, and additives were put into a ball mill 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 mm or less) and water were put into a ball mill to produce a slurry with a coal concentration of 40% and a coal particle size of 200 mesh passing through 80%. Thereafter, the mixture was dehydrated to a predetermined concentration, additives were added thereto, and the mixture was stirred with a laboratory spar to obtain a slurry.

In addition, the manufactured slurry was evaluated by the test method shown below.

1) Slurry viscosity: Measured at 25°C using a Burke rotational viscosity needle and a shear rate of 1005 ec-'.

2) Slurry life: Measured by the Bott method. In other words, put the produced slurry into a 250-inch wide robolibin and
After allowing the slurry to stand still for several months, the slurry is discharged from the polybottle by natural fall and passed through a five-dragon sieve. At this time, the amount of slurry remaining in the polybottle and the amount of slurry on the five-fin sieve was measured as the amount of agglomeration, and the aggregation rate (%) with respect to the total slurry was determined. 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.

As is clear from Table 2, by wet-producing a coal-water slurry using method (A) or method (B) according to the present invention, a slurry with good fluidity with a coal concentration of 77% and a viscosity of 700 cps or less can be obtained. It was done.

In addition, even after the slurry was allowed to stand for one month, there were almost no aggregates, the viscosity of the slurry hardly increased, and it was 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 conditions of the present invention, the naphthalene sulfonic acid formaldehyde condensate with a low degree of condensation had a coal concentration of 63%, a viscosity of 10,000 cps2t1), and poor fluidity.

In addition, although the initial viscosity of the slurry is low even when a surfactant other than the product of the present invention is used in combination, when the viscosity is measured after standing for one month, it is about 10,000 cps, and the fluidity is extremely poor (
, and the amount of agglomeration is extremely large, making it unsuitable for discharging from tanks, etc.

Example 2 The same coal as in Example 1 was used, and the additives shown in Table 1 were used. The coal-water slurry was produced by the following two methods using deashed coal.

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 coarsely crushed coal (approximately 3 mm or less) and water were put into a ball mill to produce a slurry with a coal concentration of 15% and a coal particle size of 200 mesh passing through 80%. This slurry was deashed by flotation and expanded to a predetermined concentration. Additives were added thereto and stirred with a lab body spar to obtain a slurry.

The final slurry produced was evaluated using 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 700 cps or less at a coal concentration of 80%. A slurry with good fluidity was obtained. In addition, 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 naphthalenesulfonic acid formaldehyde condensate with a small degree of condensation shown in the comparative example already has a slurry viscosity of 9000 cps or more at a coal concentration of 67%, and has poor fluidity. Further, even when a surfactant other than the product of the present invention was used in combination, the viscosity of the slurry increased to nearly 9000 cps after standing for one month, and a slurry with a long life could not be obtained.

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Claims (5)

[Claims] (1) An additive added when producing a highly concentrated coal-water slurry by pulverizing coal in the presence of water, the additive comprising: (a) a formaldehyde condensate of naphthalene sulfonic acid and/or alkylnaphthalene sulfonic acid; An additive for a long-life, high-concentration coal-water slurry, comprising a salt thereof; and (b) a polyethylene polyamine fatty acid amide compound. (2) The average degree of condensation of the formaldehyde condensate of naphthalene sulfonic acid and/or alkylnaphthalene sulfonic acid or its salt is 10 to 500, preferably 35 to 1
00. The long-life, high-concentration coal-water slurry additive according to item 1. (3) The polyethylene polyamine fatty acid amide compound is
Polyethylene polyamine H_2N-(CH_2CH_2
NH)-_nH with n of 2 to 15, preferably 3 to 10, is reacted with a fatty acid having 6 to 25 carbon atoms, preferably 8 to 19 carbon atoms, to form an amide group with 1 to 3 amide groups in the molecule, preferably 3 to 10. 2. The long-life, high-concentration coal-water slurry additive according to item 1, which is a compound containing 1 to 2 elements. (4) The blending ratio of component (a)/component (b) is 50/50 or more
The long-life, high-concentration coal-water slurry additive according to any one of items 1 to 3, which is 98/2. (5) The additive for long-life, high-concentration coal-water slurry according to any one of items 1 to 4, wherein the coal concentration is 60% by weight or more, preferably 64% by weight or more. (5) The additive for long-life, high-concentration coal-water slurry according to any one of items 1 to 5, wherein the coal is cleaned coal.