JPS58111893A - Viscosity depressant for highly concentrated coal/water slurry - Google Patents

Abstract

PURPOSE:To provide a viscosity depressant which lowers the viscosity of a coal/ water slurry and makes it possible to pump a highly concentrated coal/water slurry by adding it in a small amount, consisting of a polyether compd. (derivative) obtd. by adding an alkylene oxide to an active hydrogen-contg. amine (derivative). CONSTITUTION:An alkylene oxide such as ethylene oxide is added to an amine contg. at least one active hydrogen or its derivative, such as dimethylamine and the product is, if necessary, modified with an aicd to obtain a viscosity depressant consisting of a polyether (derivative) having an MW of 1,000-100,000. 0.01-5.0wt% said viscosity depressant is added to a coal/water slurry contg. coal at a concn. of 70wt% or above, whereby the viscosity of the slurry can be lowered to a level at which the slurry can be pumped. EFFECT:The viscosity depressant has an effect of stably dispersing coal in water.

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 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, with current technology, this method becomes difficult to pump as increasing the coal concentration significantly thickens the coal and loses its fluidity.

On the other hand, if the coal content is lowered, the transportation efficiency will decrease, and a dehydration step will become necessary for the combustion 111, 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. Japanese Patent Publication No. 54-52105. 54-52106, 54-5
3105. 54-'53106, 54-53107
．． 54-53108゜54-53109. Same 54-
65708. 54-65709. 54-11150
6. 'See 55-152789. However, these are for stably dispersing coal in oil and are not for use in coal-water slurries. :"1' JP-A-56-62538 describes an agent that stably disperses fine powder in water at a low concentration, but its purpose is different from that of a thinning agent for highly concentrated coal-water slurry. be.

The present inventors fluidized a highly concentrated coal-water slurry,
We have conducted extensive research into a thinner for coal-water slurries that makes pumping possible. Adding a small amount can significantly reduce the viscosity of coal-water slurries, making pumping possible even when the coal condensation is high due to snow. We have successfully discovered a thinning agent that provides a coal-based slurry with high quality.

By using the storage adhesive of the present invention, coal can be fluidized with a small amount of water, making it possible to not only transport it by pump, but also to burn it in a boiler as it is, and also eliminate the dehydration process before combustion. be able to. By using the thinning agent of the present invention, handling of coal becomes extremely simple, and its applications are greatly expanded.

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 of these coals. In addition, 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 is 200 mesh 0% pass or higher, this particle size is fine. This is a guideline for the particle size of charcoal. 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 sulfur have been removed.

Examples of methods for cleaning coal include heavy liquid separation method and oil aggregation method (hereinafter referred to as O
There are methods such as A method), flotation coal beneficiation method, etc. However, methods other than these may also be used and are not particularly limited.

Regarding the OA method, coal is pulverized dry or wet, then a water slurry is prepared and an appropriate amount of oil is added, or the coal is coated with oil in advance, a water slurry is prepared and stirred. Utilizing the difference in wettability of the organic and inorganic components of coal to oil and water, the organic components of coal are coagulated using oil as a binder, which selectively wets the organic components of coal. 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 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, triplex oil, C heavy oil, etc., tar or shale oil, ethylene cracked residual oil, or various blended oils, which are generally used as fuel. The oils used are heavy oils such as lubricating oils and cleaning oils. Also benzene,
Oils insoluble in water such as toluene, xylene, 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-water slurry and stirred to create foam.
Generate 70 spaces. Similar to the OA method, in this method, the organic components of the coal adhere to the 70% 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 turbine oil, tar, heavy oil, hexagonal oil, light oil, and kerosene.

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

If the coal cleaned in this manner is used, the effect of the thinner of the present invention will be significantly superior to that of uncleaned coal, and a coal-water slurry with several points higher 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 desulfurization equipment is reduced.

The thinner for coal-water slurry of the present invention uses as a starting material an amine having one or more active hydrogens, preferably three or more, more preferably five or more active hydrogens in the molecule, and derivatives thereof. It is characterized by containing a polyether compound to which an oxide has been added and the molecule thereof is 31iooo to 100,000, or a derivative in which the terminal hydroxyl group of the polyether compound is subjected to various reactions.

Examples of starting materials include the following.

Amines having one active hydrogen such as dimethylamine, N-methyllaurylcyamine, etc.; amines having two active hydrogen such as methylamine, ethylamine, propylamine, butylamine, allylamine, amylamine, octylamine, decylamine, laurylamine,
Tetradecylamine, pentadecylamine, ophtadecylamine, tallow alkylamine, coconut alkylamine,
Aniline, p-)luidine, m) Luidine, nitroaniline, benzylamine, chloroaniline, p-dodecylbenzylamine, cyclohexylamine, etc., amines having 3 active hydrogens, such as ammonia, tallow propylene diamine, etc., active hydrogen 4 Various derivatives such as amines having 5 or more active hydrogens, partial amides of amines having 2 or more active hydrogens, such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, phenylenediamine, benzidine, cyclohexyldiamine, etc. However, it can be used as long as one or more active hydrogens remain.

The thinner of the present invention is a polyether compound in which an alkylene oxide is added to these starting materials and the molecular edges thereof are 100 to 100,000, or a derivative in which the terminal hydroxyl groups of the polyether compound are reacted with each other. In particular, molecules (1t: 10,000 to 100,000) are more effective.

Ethylene oxide, propylene oxide, butylene oxide, etc. are used as the alkylene oxide, and these may be used alone or in combination of two or more types. In the case of two or more types, the arrangement is block polymerization type or random polymerization type. Although any type may be used, block polymerization type is common. In particular, a polyether compound containing ethylene oxide as the alkylene oxide, the content of which is 10 to 95% by weight, preferably 60 to 90% by weight of the total alkylene oxide, or a derivative obtained by various reactions of the terminal hydroxyl group of the polyether compound. shows excellent effects.

Derivatives obtained by subjecting the terminal hydroxyl groups of the above polyether compounds to various reactions are also effective. For example, the following can be mentioned.

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

2) Hydroxyl groups are replaced with halogens by reaction with hydrogen halide or phosphorus halide.

3) Aldehydes and carboxylic acids produced by oxidation reactions.

4) A reaction product between a hydroxyl group and a monoisocyanate.

However, the present invention is not limited to the above-mentioned examples. The reason why the present invention's thinning agent exhibits excellent effects is that after it is strongly adsorbed to the particle surface due to its special structure, many ether bonds are bonded to the surrounding water. It is thought that the coal particles are stabilized as primary particles and their fluidity is improved because the water is hydrated and the water is converted into a structure that acts like a lubricating oil. At the same time, a significant decrease in viscosity occurs.

In addition, if you use clean coal that has been deashed, the effect will further increase because deashing removes ash, which is highly hydrophilic and has fine particles with a large surface area, improving its organic properties. This is because the thinner of the present invention effectively acts on the coal surface, thereby increasing the coal concentration.

The thinner of the present invention has a zero viscosity for coal-water slurry.
．． Excellent effects can be obtained by adding 1 to 5.0% by weight, preferably 0.03 to 2.0% by weight of O. 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 drop significantly, so the coal concentration will be
It has fluidity even at 1% by weight or more, especially 70% by weight or more. If even cleaner coal is used, the coal concentration will be several points higher, generally 3 to 1
Increase by O points.

The thinner of the present invention 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 two methods: dry pulverizing the coal in advance and then mixing the thinner into an aqueous solution, or adding the thinner after making the coal-water slurry. A method of adding coal, water, and a thinner to a mill and mixing it while crushing the coal, and a method of mixing using cleaned coal instead of coal in each method. can be implemented.

The thinner of the present invention has an excellent effect of stably dispersing coal in water, and does not cause water separation even when left standing for a long period of time, for example, one month, and maintains a homogeneous coal-water slurry. There is.

As described above, the thinner of the present invention has a viscosity reduction of 0.0% for coal-water slurry. O1-5.0% by weight, preferably 0.03-20
By adding only % by weight, the viscosity of the coal-water slurry can be significantly reduced and a high-boiling coal-water slurry can be produced that can be pumped.

Examples are shown below. In the examples, percentages are by weight.

Example 1 Into an aqueous solution containing a predetermined amount of the thinner shown in Table 1,
Coal pulverized to 0 mesh 80% pass 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. After this slurry was allowed to stand for one month, the state of water separation was measured. The test results are shown in Table 2.

As shown in Table 2, when the thinner of the present invention is added, the viscosity is 1100 to 3000 even at a coal concentration of 72 to 77%.
cp and has extremely good fluidity. On the other hand, when a general anionic surfactant is added or no thinner is added, the viscosity is 20,000 at a coal concentration of 50%.
CP or more, and there is no flow at all.

The thinner of the present invention significantly reduces the viscosity of the coal-water slurry, making it possible to form a highly concentrated coal-water slurry, and also significantly improves the stability of the coal-water slurry, allowing it to stand still for more than one month. However, no coal settling occurs, and no water separation occurs at all.

Example 2 A cleaned 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° (゛), and the fluidity is also observed. After this slurry is allowed to stand for one month, the state of water separation is measured.

The viscosity reducing agents of the present invention used in the test are shown in Table 1. The test results are shown in Table 3.

As shown in Table 3, when the thinner of the present invention is added to the cleaned coal-water slurry, the viscosity is 1300 to 2500 cp even at a coal concentration of 76 to 80%, and the fluidity is extremely good. On the other hand, when a thinner other than the present invention is added or no thinner is added, the viscosity is 20% at a coal concentration of 50%.
000 cp or more and does not flow at all.

(Margin below)

Claims (5)

[Claims] (1) A thinning agent for highly concentrated coal-water slurry used to reduce the viscosity of the coal-water slurry and improve its fluidity, and contains one or more active hydrogen atoms in the molecule. Preferably, an amine having 3 or more, more preferably 5 or more -F and a derivative thereof is used as a starting material, and an alkylene oxide is added thereto to form a polyether compound or the polyether compound whose molecule is [1,000 to 100,000]. A thinning agent for coal-water slurry, characterized in that it contains as an essential component a derivative obtained by variously reacting the terminal hydroxyl groups of. (2) The thinner for coal-water slurry according to claim 1, wherein the polyether compound has a molecular weight of 10,000 to 10,000. (3) The coal-water slurry according to claim 1 or 2, which contains ethylene oxide as the alkylene oxide, and the content thereof is 10 to 95% by weight, preferably 60 to 90% by weight of the total alkylene oxide. Thinning agent. (4) The 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 or more, 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.