JPS58120696A - Viscosity reducing agent for coal-water slurry of high concentration - Google Patents

Abstract

PURPOSE:A viscosity reducing agent for a coal-water slurry of high concentration, containing a specific crosslinked polyether compound (derivative) as an essential component, and capable of improved fluidity and stability and pumping the coal water-slurry. CONSTITUTION:A viscosity reducing agent containing a crosslinked polyether compound (derivative) having 7,000-100,000, preferably 10,000-100,000, molecular weight which is an alkylene oxide adduct with 30-95wt% ethylene oxide content of an aliphatic aldehyde condensate of an aromatic compound having phenolic hydroxyl groups as an essential component. The amount of the viscosity reducing agent to be added to a coal-water slurry is usually 0.01-5.0wt%, preferably 0.03-2.0wt%, based on the coal-water slurry.

Description

[Detailed description of the invention] The present invention relates to a thinner for coal-water slurries.

More particularly, it relates to a thinning agent for dispersing pulverized coal in water to provide a highly concentrated coal-water slurry that can be pumped.

In recent years, due to the depletion of oil resources, the use of coal has been reconsidered.
Various ways of using it are being considered. However, unlike oil, coal is a solid substance and cannot be transported by pump. For this reason, various methods are being considered for pulverizing coal and dispersing it in water to form a water slurry. However, this method has limited technology, and as the coal concentration increases, the viscosity increases significantly and fluidity disappears, making pumping difficult. On the other hand, lowering the coal concentration reduces transportation efficiency and requires a dehydration process before combustion, which is expensive and impractical.

The present inventors have previously succeeded in stably dispersing coal in oil using polyethers, and are currently applying for a patent. JP-A No. 54-52105, No. 54-52106, No. 54-5
8105, 54-58106, 54-53107,
54-53108, 54-58109, 54-6
5708, 54-65709, 54-111506
, 55-152789. However, these are for stably dispersing coal in oil and are not for use in coal-water slurries.

In addition, the present inventors are currently applying for a patent on the use of polyether compounds as a thinning agent for highly concentrated coal-water slurries; We thought that by increasing the number of polar groups, a better viscosity reducing effect could be obtained, and a crosslinked polyether compound obtained by crosslinking polyether compounds showed excellent effects as a viscosity reducing agent for highly concentrated coal-water slurries. We have discovered that this is the case, and have arrived at the present invention.

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. Furthermore, the particle size of the coal in the water slurry may be any particle size as long as it is powder, but since the pulverized coal currently burned in thermal power plants has a 200 mesh pass 7% weight or higher, this particle size is suitable. is a guideline for the particle size of pulverized coal. However, the thinner of the present invention is not affected by particle size and exhibits excellent effects on coal powder of any particle size.

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

Examples of methods for cleaning coal include a heavy liquid separation method, an oil agglomeration method (hereinafter referred to as an OA method), and a 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 create an oil that selectively wets the organic content of the coal by utilizing the difference in wettability of the coal and inorganic substances to oil and water. is used as a binder to cause agglomeration of coal organic matter. On the other hand, inorganic substances have a weak affinity with oil, so
Since it is liberated in water, it is a method that can simultaneously remove inorganic substances by separating the water from the coagulated coal. OA
The coal concentration in the coal-water slurry of the method is usually 10-65% by weight.

The oil used in the OA method is crude oil or various fractions obtained from crude oil, such as kerosene, light oil, A heavy oil Δ↑1, B heavy oil,
These include C heavy oil, tar, shale #j, ethylene decomposition residual oil, and various blended oils, oils commonly used as fuel, and mineral oils such as lubricating oils and cleaning oils. Water-insoluble oils such as benzene, toluene, xylene, and animal and vegetable oils may also be used, but 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% by weight or less based on 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-8 water slurry and stirred to create foam, thereby forming a living film of 70s. Similar to the OA method, the wooden sword method is a method in which the organic components of the coal are attached to the froth oil film, but the inorganic materials are liberated in the water and can be separated from the coal organic materials.

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

Generally, more than &IO weight % of inorganic substances are removed from coal by the above method.

When using coal that has been cleaned in this manner, 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 the final effect, boiler corrosion during combustion is suppressed, and the burden on ash removal equipment and desulfurization equipment is reduced, among other great benefits.

Wooden lX! The thinner for coal-water slurry No. 1-1 is produced by adding an alkylene oxide to an aliphatic aldehyde condensate of an aromatic compound having a phenolic hydroxyl group, which always contains ethylene oxide as the alkylene oxide, and whose content is 30%. A crosslinked polyether compound having a molecular weight of 7,000 to 100,000, preferably 10,000 to 10,000, obtained by crosslinking 95% by weight of a polyether compound, or the terminal hydroxyl group of the crosslinked polyether compound or the crosslinked polyether compound is subjected to various reactions. It is characterized by containing a derivative.

Examples of aromatic compounds having a phenolic hydroxyl group include: 1) Phenols and substituted phenols such as phenol, cresol, xylenol, butylphenol, nonylphenol, aminophenol, and hydroxybenzoic acid, 2) Naphtho-/pemethylnaphthol, butylnaphthol, Naphthols and substituted naphthols such as octylnaphthol 3) Polyhydric phenols such as catechol, resorcinol, and pyrogallol 4) Polyhydric naphthols such as naphresorcin and α-naphthohydroquinone 5) Condensed phenols such as bisphenol A1 and bisphenol s Can be mentioned.

Examples of fatty acid aldehydes include formalin, acetaldehyde, and glyoxal, with formaldehyde being common.

Examples of alkylene oxides include ethylene oxide, propylene oxide, and butylene oxide 1! is used, and the addition method may be either a block polymerization type or a random polymerization type, but a crosslinked polyether compound using a block polymerized ethylene oxide terminal is particularly effective.

Ethylene oxide content is 30% of total alkylene oxide
6 to 95% by weight, preferably 6 to 95% by weight,
More preferably, those in which 70 to 90% by weight of a polyether compound is crosslinked are excellent.

As a crosslinking agent for the polyether compound, polyvalent isocyanate, polyvalent epoxy, polyvalent aldehyde, polyvalent carboxylic acid or polyvalent carboxylic acid reactive derivative, peroxide (radical generating catalyst), and formalin can be used. Specifically, polyvalent isocyanate compounds include hexamethylene diisocyanate, tolylene diisocyanate, xylene diisocyanate, 1,5 naphthylene diisocyanate, 4,4' diphenylmethane diisocyanate, and polyvalent epoxy compounds include: Examples include diglycidyl bisphenol A1 diglycidyl ethylene glycol and diglycidyl tetraoxyethylene glycol.

Polycarboxylic acids or polycarboxylic acid reactive derivatives, such as carboxylic acids having two carboxylic acids, such as succinic acid, malonic acid, phthalic acid, maleic acid, curtaric acid, adipic acid, azelaic acid, cepatic acid, totecanniic acid, dimer acids, 0-7 enylene diacetic acid, etc., octavalent carboxylic acids, such as hemimellitic acid, trimellitic acid, etc., tetravalent carboxylic acids,
Examples include butanetetracarboxylic acid, pyromellitic acid, ethylenecyaminetetraacetic acid, etc., carboxylic acids with a valence of 5 or more, such as acrylic acid polymers, acrylic acid copolymers, methacrylic acid polymers, methacrylic acid copolymers, Maleic acid polymers, maleic anhydride copolymers, partially saponified products of polymers and copolymers of acrylic esters and methacrylic esters, and acid anhydrides and acid halides of the above acids can be used.

Peroxides (radical generation catalysts) include hydrogen peroxide,
Benzoyl peroxide, di-tert-butyl peroxide, cumene oxide, dicumyl peroxide, and the like are optionally used.

When crosslinking using a polyvalent incyanate compound or a polyvalent epoxy compound, the proportion of the crosslinking agent used is arbitrary, but generally it is 0.0 with respect to the terminal hydrogen group equivalent of the polyether.
5 to 5 equivalents, preferably 0.1 to 3 equivalents B (used).

As for the crosslinking conditions, the polyether compound and the crosslinking agent are mixed, and the temperature is heated to 40 to 150°C, preferably 50 to 120°C, while stirring.
Heating is carried out at a temperature in the range of 0.degree. C., and if necessary, an acid or base catalyst usually used for crosslinking can be added once a month.

1 polycarboxylic acid or polycarboxylic acid reactive derivative
- In the case of crosslinking, the proportion of the crosslinking agent used is arbitrary; generally, 0.05 to 5 equivalents are preferable, but 0.1 equivalents to 0.1 equivalents to the terminal hydroxyl group of polyether. Use the 3rd duty.

As for the crosslinking conditions, when using a polyhydric carboxylic acid, the polyether compound and the crosslinking agent are heated at 60°C to 250°C under reduced pressure in the presence or absence of an inert solvent as necessary.
The purpose can be easily achieved by carrying out the dehydration by heating, preferably at a temperature in the range of 80°C to 220°C. In this case, a common esterification catalyst can be used to facilitate the reaction.

However, when using a polyhydric carboxylic acid halide, the polyether compound and the crosslinking agent are passed through an inert gas in the presence or absence of an inert solvent to facilitate dehydrohalogenation, or Using a known agent that can easily capture the generated hydrogen halide,
The purpose can be easily achieved by reacting at 0C1, preferably in the range of 0°C to 120°C.

When crosslinking using peroxide, the ratio of peroxide (radical generating catalyst) used is 0.0 to polyethers.
Any range from 5% to 10% by weight, preferably 0.1% to 5% by weight may be utilized.

For example, Journal
of Applied Polymer 5cien
ce Vo17 pp461-468 (1963), etc., and is complete. For crosslinking at 11 Kg, these known techniques can be used as is. Generally, a predetermined amount of peroxide is mixed with polyethers in the presence or absence of a solvent, and the mixture is heated at 50°C to 250°C.
Preferably, the reaction is carried out in the range of 70°C to 180°C, and if necessary, i! The target substance can be obtained by distilling off the solvent.

When crosslinking is carried out using formalin, known techniques can be used, and it is generally carried out as follows.

That is, 0.1 to 10 equivalents of formalin, preferably 0.5 to 5 equivalents are used, and 0.05 to 0.005 equivalents of formalin are added to 1 equivalent of the polyether compound, and 60 to 10 equivalents of formalin are used.
The temperature was raised to 0'CK, stirred for 1 to 3 hours, and then heated to 10
The reaction is completed by raising the temperature to 0-180°C.

Only crosslinked polyether compounds obtained by crosslinking polyether compounds having a molecular weight of 70,001 to 100,000, preferably 10,000 to 100,000 are effective.

Further, derivatives obtained by subjecting the terminal hydroxyl groups of the crosslinked polyether compound L to various reactions are also effective.

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

2) Hydroxyl groups are replaced with halogens by reaction with hydrogen halides or phosphorous halides.

3) Aldehydes and carboxylic acids produced by oxidation reactions.

However, the present invention is not limited to the above example.

In general, polyether compounds have the drawback that when attempting to increase the molecular weight per convex hydrogen to 3,000 or more, particularly 6,000 or more, by-products are likely to be produced and it is difficult to manufacture. Drugs with a large number of active hydrogens (6 or more) are generally difficult to obtain, and if a starting material with a small number of active hydrogens is used, as mentioned above, it is difficult to increase the molecular weight and form a steric structure, and the number of polar groups is also limited. There is.

In order to improve these drawbacks, the polyether compound was cross-linked to increase the molecular weight, increase the volume of the three-dimensional structure, and increase the number of polar groups in one molecule, resulting in a remarkable effect.

We succeeded in creating an excellent drug.

The reason why the thinner for coal-water slurry of the present invention exhibits excellent effects is that, as shown above, the thinner of the present invention exhibits excellent effects.
Because the number of polar groups in one molecule increased significantly due to crosslinking,
It is thought that it is very strongly adsorbed on the surface of coal particles, hydrates surrounding water, and transforms this water into a structure that has a lubricant-like effect. At the same time, crosslinking significantly increases the bulk of the three-dimensional structure of the molecules and increases the molecular spacing, which makes the coal particles stable as primary particles, improves fluidity, and appears to cause a significant decrease in viscosity. In addition, the viscosity reducing agent of the present invention is
It is thought that the content of ethylene oxide is within a suitable range, and the adsorption to the particles becomes even stronger.

This is because if clean coal is used, the organic matter will be removed and the thinner of the present invention will effectively act on the surface of the coal, which has been exposed to organic matter, thereby reducing the coal concentration. You can measure the rise.

Such a thinner of the present invention can be used for coal-water slurry.
0.01-5.0% by weight, preferably 0.03-2.0
Excellent effects can be achieved by adding % by weight.

The fluidity limit of a coal-water slurry differs depending on the type and particle size of the coal, but generally, if a thinner is not added, the fluidity will be lost at a coal concentration of around 50% by weight, but with the addition of the thinner of the present invention. If this is done, the viscosity will be significantly lowered, and the coal has fluidity even when the coal concentration is 61% by weight or more, especially 70% by weight or more. Furthermore, when using cleaner coal, the coal concentration increases by several points, compared to the general 1l-
Increase by 10 points from t8.

The wood thinning agent can also be used in combination with other surfactants. − Regarding the method for producing coal-water slurry and the method for adding a thinner, there are methods such as dry-pulverizing coal in advance and then mixing a thinner into an aqueous solution, or adding a thinner after making a coal-water slurry. How to add? Any method can be used, such as adding coal, water, and a thinner into a mill and mixing while crushing the coal, or using cleaned coal instead of coal in each method. .

The thinner of the present invention has an excellent effect of stably dispersing coal in water, and maintains a homogeneous coal-water slurry without causing water separation even when left standing for a long period of time, for example, one month. I'm here.

As described above, the thinner of the present invention has a viscosity reduction of 0.0% for coal-water slurry. 2.0% by weight of O2N, preferably 0.03-2.0% by weight.
The viscosity of coal-water slurry can be significantly reduced just by adding 11:% of coal-water slurry, and pumping becomes difficult at high concentrations.
A highly efficient coal-water slurry can be made.

Examples are shown below. In the examples, % is ilj llj K
evening.

Example 1 Into an aqueous solution containing a predetermined amount of the thinner shown in Table 1,
Coal pulverized to 0 mesh 80% bath is added at room temperature with stirring to prepare a coal-water slurry of a predetermined concentration. The viscosity of this slurry is measured at 25°C and the fluidity is observed. Furthermore, this slurry was poured into a 500rd cylinder to a height of 18cm, and after being left undisturbed for one month, it was returned to the former residence ().

l cm from the bottom) and the coal concentration in the lower layer (l cm from the bottom). The test results are shown in Table 2. As shown in Table 2, when the thinner of the present invention is added, the coal concentration is 74.
Even at ~77%, the viscosity is 900 to 2400 cp, and the fluidity is extremely good. The slurry is still very stable with almost no coal sedimentation even after one month of static heating. On the other hand, when a general anionic UkJ activator is added or no thinner is added, the viscosity becomes 20.000 cp or more at a coal concentration of 50%, and there is no flow at all.

Example 2 A clean coal-water slurry of a predetermined concentration is prepared in the same manner as in Example 1 using cleaned coal. The coal particle size is 200 mesh 80% bath. The viscosity of this slurry is measured at 25°C, and the loose fluidity is also observed.

After this slurry was allowed to stand still for one month, the coal concentration in the upper and lower layers was determined to be 6 L, as in Example 1.

The uninvented thinners used in the test are shown in Table 1. The test results are shown in Table 3.

As shown in Table 3, when the viscosity reducing agent (unused) IJ is added to the cleaned coal-water slurry, the viscosity is 1100 to 2400 cp even when the coal concentration is 78 to 80%, and the fluidity is extremely good. In addition, the slurry is extremely stable with almost no coal settling even after it has been allowed to stand for one month. - If a thinning agent other than the one invented by the strength wood is added or if no thinning agent is added, the viscosity will be 20,000 cp or more at a coal concentration of 50%, and there will be no flow at all.

(Left below) , 1st polyether compound)
−−,,−−−−−,−,,,,,−,,,,−1,,
, -* () indicates the addition lid of peroxide to the polyether compound.

PO, Probile/Oxide EO: Ethylene oxide BO Nifdelene oxy7t' TDI:) Lylene diiso crosslinked polyether compound 1 X4 nate XpI: Quinrylene diisocyanate No. 2 1) ○ Good
3 1) ○ Good

Claims (5)

[Claims] (1) A thinning agent for highly concentrated coal-water slurry used to reduce the viscosity of coal-water slurry and improve fluidity and stability, which is an aliphatic aldehyde of an aromatic compound having a phenolic hydroxyl group. A polyether compound in which an alkylene oxide is added to a condensate and the content of ethylene oxide in the added alkylene oxide is 80 to 95% by weight is crosslinked, and the molecular weight is 7,000 to 100,000, preferably 10,000 to 10,000. A thinning agent for coal-water slurry, characterized in that it contains as an essential component a crosslinked polyether compound or a derivative obtained by subjecting the terminal hydroxyl group of the crosslinked polyether compound to various reactions. (2) The polyether compound is crosslinked using one or more selected from polyvalent incyanate, polyvalent epoxy, polyvalent aldehyde, polyvalent carboxylic acid or polyvalent carboxylic acid reactive derivative, peroxide, and formalin. The thinning agent for coal-water slurry according to claim 1, characterized in that the thinner is used in the coal-water slurry. (3) Claims in which the polyether compound before crosslinking contains block-polymerized ethylene oxide at the end as an alkylene oxide, and the content thereof is 60 to 95% by weight, preferably 70 to 90% by weight of the added alkylene oxide. The thinning agent for stone-water slurry according to item 1 or 2. (4) A thinning agent for coal-water slurry according to any one of claims 1 to 3 for use in a coal-water slurry having a coal concentration of 61% by weight, preferably 70% by weight or more. (5) The thinner for coal-water slurry according to any one of claims 1 to 4, wherein the coal is cleaned coal.