JPH03294393A - Additive assistant for coal-water slurry - Google Patents

Abstract

PURPOSE:To obtain the subject additive assistant, containing a respective specific ionic compound or complexing agent and nitrogen-containing compound and capable of preventing coal particles from aggregating and depositing even in preservation under heated conditions and imparting excellent heat resistance to a slurry. CONSTITUTION:The objective additive assistant containing (A) (i) an ionic compound capable of forming an insoluble salt with polyvalent metallic ions and/or (ii) a complexing agent capable of forming a stable complex compound with the polyvalent metallic ions and (B) (i) a polyamine fatty acid amide prepared by reacting a 6-30C fatty acid with a 2-30N polyamine and/or (ii) an amine-based compound composed of an amine (salt) and/or a quaternary ammonium salt having 1-3 long-chain aliphatic hydrocarbon groups.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an additive that is added to a coal-water slurry to improve the thermal stability of the slurry.

From the perspective of soaring oil prices and the diversification of energy resources,
In recent years, the use of coal has attracted attention.

Coal is a solid fuel and is difficult to handle, so it has been proposed to pulverize it into a water slurry.By turning coal into a water slurry, it becomes possible to transport it through pipes, which is similar to liquid fuel. However, it is necessary to increase the concentration to improve transport efficiency. However, it is difficult to obtain a slurry with a high concentration of 50% or more by simply dispersing coal in water, and if left to stand still, the coal powder will settle and become non-uniform, resulting in poor storage stability. There is a problem with this.

Therefore, it has been proposed to mix a dispersant into the slurry to increase the concentration and improve the dispersion stability. Such dispersants include, for example, polystyrene sulfonate, formalin condensate of naphthalene sulfonate,
Salts of sulfonated formalin condensates of melamine, lignin sulfonates, etc. are used.

In addition, a two-component system (JP-A-60-60
A combination system such as the one disclosed in Japanese Patent Publication No. 191 has also been reported.

However, although a highly concentrated coal-water slurry with fluidity can be obtained by adding a dispersant such as styrene sulfonate, this slurry has a problem in heat resistance.

In other words, 1-coal-water slurry is produced by pulverizing or stirring 1-coal with water for the purpose of dispersing coal particles in water or pulverizing the coal (wet pulverization), but due to the heat generated during this pulverization and stirring process. , the temperature of the resulting coal-water slurry increases. If this heated slurry is directly transferred to a storage tank and stored, there is a problem in that the coal particles aggregate to form soft aggregates or settle and accumulate at the bottom of the storage tank to form a hard pack. On the other hand, if the coal-water slurry is cooled and then stored in a storage tank, the original dispersion stability will be exhibited and the above-mentioned problems will be prevented. Therefore, conventionally, the produced slurry at elevated temperature was cooled with cooling water, and then the slurry was transferred to a storage tank and stored.

However, this method requires a large amount of cooling water and time for cooling, which poses an economical problem.

In order to solve these problems, we investigated changes in the properties of coal-water slurry when stored at high temperatures, and found phenomena such as an increase in polyvalent metal ions and a decrease in slurry pH. As an additive that solves the phenomenon caused by an increase in polyvalent metal ions, Japanese Patent Application Laid-Open No. 58-13418
Publication No. 9, Publication No. 59-58092, Publication No. 59-206
There are various additives disclosed in Japanese Patent No. 491 and Japanese Patent No. 60-71693. Specifically, JP-A-58-1
No. 34189 discloses alkali metal silicates and polyacrylates, and JP-A No. 59-58092 discloses phosphates,
Tartrate, citrate, J, ethylenediaminetetraacetic acid salt, ethylenediaminetetraacetic acid, oxalic acid, metaphosphoric acid, orthophenanthroline in JP-A-59-206491, hexametaphosphoric acid in JP-A-60-71693. Sodium, sodium tripolyphosphate are listed. However, with regard to the high-temperature storage stability of coal-water slurry, some methods were effective to some extent, but others were not effective at all. In fact, each of the above-mentioned publications deals with technical issues such as a reduction in the viscosity of the slurry, and there is no mention of high-temperature storage stability.

Therefore, as a result of extensive research into additives that have excellent high-temperature storage stability for coal-water slurry, we have completed the present invention.

The present invention aims to provide an additive auxiliary agent that can prevent coal particles from aggregating and accumulating even when the coal-water slurry is stored at elevated temperatures, and can impart excellent heat resistance to the coal-water slurry. It is.

The additive auxiliary agent for coal water slurry of the present invention is characterized by containing the following components (A) and (B).

(A) At least one compound selected from the following (A-1) and (A-2).

(A-1) An ionic compound that forms an insoluble salt with a polyvalent metal ion.

(A-2) A complex-forming agent that forms a stable complex compound with a polyvalent metal ion.

(B) At least one nitrogen-containing compound selected from (B-1) and (B-2) below.

(B-1) A polyamine fatty acid amide obtained by reacting a fatty acid having 6 to 30 carbon atoms with a polyamine having 2 to 30 nitrogen atoms.

(B-2) An amine compound selected from amines, amine salts, and quaternary ammonium salts having 1 to 3 long-chain aliphatic hydrocarbon groups.

The present invention will be explained in more detail below.

As component (A), the above (A-1) or (A-2
) is used.

As the ionic compound of component (A-1), those that form insoluble salts with polyvalent metal ions are used, such as alkali metal silicates, alkali metal carbonates, alkali metal hydroxides, alkali metal sulfates, Examples include alkali metal sulfites.

As the complex-forming agent for component (A-2), one that forms a complex compound with a polyvalent metal ion is used, and examples thereof include carboxylic acid-based, amino acid-based, oxycarboxylic acid-based, and condensed phosphoric acid-based. Among these, ethylenediaminetetraacetic acid, ethylenediaminetetrapropionic acid, diethylenetriaminepentaacetic acid, gluconic acid, tartaric acid, citric acid, tripolyphosphoric acid, pyrophosphoric acid, hydroxyethane diphosphonic acid, or a salt thereof is effective.

In addition, suitable salts for these components (A-2) include water-soluble salts such as alkali metal salts such as lithium, sodium, and potassium, alkaline earth metal salts such as magnesium and calcium, ammonium salts, and organic amine salts. and preferably sodium, potassium and ammonium salts.

Component (A) is 0.01 to 2% by weight in the coal water slurry.
, preferably 0.02 to 1% by weight.

As the nitrogen-containing compound of component (B), the above-mentioned (B-1)
or (B-2) is used, and these are added singly or in combination.

The fatty acid in the polyamine fatty acid amide of component (B-1) is one having 6 to 30 carbon atoms, and the hydrocarbon group may be either aliphatic or aromatic. The number of carboxyl groups in this fatty acid, which may be chained or branched, saturated or unsaturated, is 1.
Preferably one or two in the molecule.

Specific examples of fatty acids include octanoic acid, palmitic acid,
Aliphatic carboxylic acids such as myristic acid, stearic acid, behenic acid, 2-ethylhexanoic acid, isostearic acid, oleic acid, coconut fatty acid, soybean fatty acid, tallow fatty acid, hydrogenated tallow fatty acid, adipic acid, sebacic acid; benzoic acid acid,
Examples include aromatic carboxylic acids such as phthalic acid.

As polyamines, those containing 2 to 30 nitrogen atoms are used, and those having a skeleton represented by the following formula (1) or (II) are typical.

-C, H,, NH-... (1) C, H,, NH- / 10, H2, N...
(II)\C,H,,NH- (In the formula, m = = 1 to 4.) Specific examples of polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, pentaethylenehexamine, hexaethylenehbutamine. , propylene diamine, dipropylene triamine, pentapropylene hexamine, polyethyleneimine, and the like.

The reaction between fatty acids and polyamines is carried out under normal pressure or reduced pressure.
It can be carried out at 0 to 200°C, preferably 80 to 180°C, for 1 to 20 hours. Although a catalyst is not particularly required, a commonly used catalyst may be used.

It is appropriate to react 0.5 to 1.5 mol, preferably 0.8 to 1.2 mol, of fatty acid per mol of polyamine.

Incidentally, in the obtained polyamine fatty acid amide, the remaining amino groups may be neutralized with a suitable acid if necessary. The neutralization rate is not particularly limited, and the acid used for neutralization.

It may be an inorganic acid or an organic acid, and specific examples include acetic acid, lauric acid, coconut fatty acid, stearic acid, tallow fatty acid, and benzoic acid.

The amine compound as component (B-2) includes amines having 1 to 3 long-chain aliphatic hydrocarbon groups, amine salts, quaternary
At least one class ammonium salt is used. As the long-chain aliphatic hydrocarbon group, an alkyl group or alkenyl group having 6 to 20 carbon atoms is suitable. Any appropriate counter ion can be used to constitute the amine salt or quaternary ammonium salt.

Specific examples of the amine compound as component (B-2) are as follows.

(1) Amines: Mono- or chasialkylamine, monododecylamine, distearylamine, mono- or distearylamine, di-hardened tallow alkylamine, monooleylamine, coconut alkyl trimethylene diamine, tallow alkyl trimethylene diamine, coconut alkyl dipropylene Triamin.

(2) Amine salts: hydrochlorides, acetates, long-chain fatty acid salts, etc. of the above-mentioned amines; more specifically, for example, hydrochlorides of monococonut alkyl amines, acetates of monohardened tallow alkyl amines, coco alkyl trichlorides, etc. Methylene diamine acetate, coconut alkyl dipropylene triamine acetate.

Examples include oleate salts of tallow alkyl triamines.

(3) Quaternary ammonium salt: Synthesized by reacting the above amine with a quaternizing agent such as a lower alkyl halide or dialkyl sulfate. More specifically, they include octyltrimethylammonium chloride, didodecyldimethylammonium chloride, coconut alkyltrimethylammonium chloride, shasiaalkyldimethylammonium acetate, beef tallow alkyltrimethylammonium chloride, and dicured beef tallow alkyldimethylammonium methyl sulfate.

These (B) components are present in the coal water slurry at 0.01 to 2
It is desirable to add it in an amount of 0.02 to 1% by weight, preferably 0.02 to 1% by weight.

The additive auxiliary agent of the present invention can be added to a coal-water slurry that has been mixed with a dispersant to stabilize the dispersion. Coal-water slurry has good storage stability if it is cooled after production and then transferred and stored in a storage tank. However, if it is transferred and stored in a storage tank at an elevated temperature after production, the coal particles will aggregate. The additive auxiliary agent of the present invention may become coarse or coal particles may accumulate at the bottom, making it difficult to discharge from the storage tank. Particulate formation or deposition can be prevented.

Coal-water slurry can be obtained by grinding coal using a dry grinding method or a wet grinding method to form a water slurry, and the dispersant and the additive auxiliary agent of the present invention are added so as to be uniformly contained in the final water slurry. It can be added at an appropriate step. For example, if coal fine powder is obtained by dry crushing method.

A high concentration water slurry can be prepared by dissolving or dispersing the dispersant and additive auxiliary agent in water and adding fine coal powder to it using an appropriate mixing device.Also, when adopting the wet pulverization method, type 11 The dispersant and additive aid may be added in advance to the water used for pulverization, or may be added during or after wet pulverization.

The temperature of the obtained coal-water slurry increases due to heat generation during crushing or stirring, but by including the additive auxiliary agent of the present invention, it can be directly transferred to a storage tank and stored without being cooled. When the degree of temperature rise is large,
In some cases, it may be desirable to store the product after cooling, and even in that case, the cooling temperature can be lowered.

The additive auxiliary agent of the present invention can be applied to slurries of various coals such as brown coal, subbituminous coal, bituminous coal, and anthracite coal. The coal particle size in the slurry can be used as long as it does not substantially exceed 1 +++ m, but generally speaking, the smaller the particle size, the better the dispersion stability of the water slurry. % or more, particularly preferably in the range of 65 to 95% by weight.

Any dispersant can be used as long as it can impart dispersion stability to the coal-water slurry, and a typical example is a water-soluble sulfonic acid polymer having an aromatic ring or triazine ring and a sulfonic acid group in the molecule. It is.

Specific examples of water-soluble sulfonic acid polymers include:

There are polyaromatic sulfonic acids or their salts, and other aromatic sulfonic acid formaldehyde condensates or their salts,
Examples include aminotriazine formaldehyde condensed metal sulfonic acid or its salt, lignin sulfonic acid or its salt.

Among these, by using a polyaromatic sulfonic acid, especially a salt of polystyrene sulfonic acid (or polystyrene sulfonic acid) in combination with the additive of the present invention to make a coal water slurry additive, excellent fluidity and heat resistance can be achieved in the slurry. can be granted to

Polyaromatic sulfonic acids or salts thereof can be obtained by polymerizing or copolymerizing a polymerizable aromatic sulfonic acid (monomer) with other monomers, and can also be obtained by sulfonating an aromatic polymer (polymer) and, if necessary, neutralizing it. Specific examples of zero-polymerizable aromatic sulfonic acids, of which polystyrene sulfonic acid (salt) is a typical example, include styrene sulfonic acid, α-methylstyrene sulfonic acid, methyl nucleus-substituted styrene sulfonic acid, Vinylnaphthalene sulfonic acid is mentioned. Sulfonation of aromatic polymers such as polystyrene and poly-α-methylstyrene can be carried out in a conventional manner using a suitable sulfonating agent such as sulfuric anhydride or chlorosulfonic acid.

The degree of sulfonation of polyaromatic sulfonic acid (salt) is 75 to
100% is preferable, more preferably 80-95%. The weight average molecular weight of polyaromatic sulfonic acid (salt) is
2,000 or more is suitable, preferably about s,ooo
~80,000.

The formaldehyde condensate of aromatic sulfonic acid or its salt is preferably one having a weight average molecular weight of 700 or more, preferably 800 to 5,000. Examples of the aromatic sulfonic acid include benzenesulfonic acid, short-chain alkylbenzenesulfonic acid, naphthalenesulfonic acid, short-chain alkylnaphthalenesulfonic acid, phenolsulfonic acid, naphtholsulfonic acid, taleosote oil sulfonated product, and the like.

A sulfonated product of an aminotriazine formaldehyde condensate or a salt thereof is obtained by further sulfonating a polycondensation reaction product of an amino-8-triazine compound, such as melamine, hexamethylolmelamine, acetoguanamine, benzoguanamine, etc., and formaldehyde. It is a sulfonated product or a salt thereof, and has a weight average molecular weight of 700.
or more are suitable, preferably 800 to 5,0
The range is 00.

Lignosulfonic acid or its salt is obtained from sulfur pulp cooking effluent, and its molecular weight and degree of sulfonation vary depending on the type of wood and cooking conditions.

The water-soluble sulfonic acid polymer may be in the acid type or the salt type, but it is preferable to have half or more of the sulfonic acid groups neutralized.Salts of such polymers include lithium, sodium, potassium, etc. Alkali metal salts, alkaline earth metal salts such as magnesium, calcium, ammonium salts and organic amine salts are suitable, preferably sodium, potassium and ammonium salts.

When a water-soluble sulfonic acid polymer is used as a dispersant, the pH of the coal-water slurry is preferably on the alkaline side, preferably P) 19 or higher.

Further, a sulfonated dicyclopentadiene polymer, an anionic surfactant, a nonionic surfactant, an alkali agent, etc. can also be added to the coal water slurry.

Examples of anionic surfactants include alkylbenzene sulfonic acids and polyoxyethylene alkyl ether sulfates.

Examples of nonionic surfactants include polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid amide, alkylene oxide polymers such as polyethylene oxide-polypropylene oxide, and brobylene oxide/ethylene oxide adducts of polyethylene imine. Can be mentioned.

As the alkali agent, sodium hydroxide, potassium hydroxide, etc. can be suitably used, and these can be added at any stage of slurry production.

Effects of the Invention According to the present invention, by adding a compound that forms an insoluble compound or a complex compound with a polyvalent metal and a specific nitrogen-containing compound to a coal-water slurry fluidized by a dispersant, , improving the thermal stability of coal-water slurry1
Even when the coal-water slurry is stored at elevated temperatures, it is possible to prevent the formation of hard packs due to agglomeration and coarsening of coal particles and sedimentation.

Therefore, even if the obtained coal-water slurry is heated due to heat generation during the manufacturing process of the coal-water slurry such as the wet step 1 or the stirring and dispersion process, this heated slurry can be used as it is.
Alternatively, it can be transferred to a storage tank and stored through a simple cooling process.

Example: A stainless steel ball mill of 6QC (inner diameter 19 cm) accommodates stainless steel balls at a filling rate of 50%.

1000 g of coal crushed to 3 mm or less, water and polystyrene sulfonate as a dispersant (molecular weight 15000,
After adding 6 g of sulfonation degree (92%), it was rotated at 65 rpm, and the particle size of the slurry (
While measuring the number of particles of 74 μm or less, the powder was ground until the amount of particles of 74 μl or less became 80%. After pulverization, the slurry was taken out from the ball mill, and a predetermined amount of additive was added to the slurry.
The mixture was mixed and stirred for 10 minutes using an RP filter. After stopping stirring, the slurry was transferred into a cylindrical container and its thermal stability was evaluated.

Evaluation of thermal stability: Put the slurry in a 250 mΩ wide-mouth plastic bottle, let it stand at 65°C for 3 days, and then pour it onto a 16-mesh sieve.The amount on the sieve and the amount remaining in the plastic bottle (relative to the total amount of slurry) weight%) was determined. Furthermore, the hardness of the slurry remaining on the plastic bottle and the sieve was evaluated based on the feel of the slurry when stirred with a spatula using the following criteria.

0 Niss slurry is soft Δ Niss slurry is hard × Niss slurry is extremely hard Below, the properties of the coal used (Table 1), the properties of the ionic compound or complex forming agent used (Table 2), and the nitrogen-containing compound used Properties (Tables 3 and 4), coal water slurry preparation conditions, and evaluation results (Table 5) are shown in order.

It can be seen that the added auxiliary agent of the present invention improves thermal stability and prevents coal particles from agglomerating, settling to the bottom, and forming a hard back even under elevated temperature storage. In addition, when the stability of the coal-water slurry was evaluated according to the above-mentioned thermal stability evaluation method except for changing the standing temperature from 65°C to 25°C, it was found that the present invention in Table 5 below at room temperature No significant difference was observed in the stability of the slurry between the Examples and Comparative Examples.

Table-1

Claims (1)

[Claims] 1. (A) at least one compound selected from the following (A-1) and (A-2); and (A-1) an ion that forms an insoluble salt with a polyvalent metal ion. Compound (A-2) Complex-forming agent that forms a stable complex with a polyvalent metal ion (B) At least one nitrogen-containing compound (B-1) selected from the following (B-1) and (B-2) -1) Polyamine fatty acid amide obtained by reacting a fatty acid having 6 to 30 carbon atoms with a polyamine having 2 to 30 nitrogen atoms (B-2) containing 1 to 3 long chain aliphatic hydrocarbon groups. An additive auxiliary agent for coal-water slurry, characterized in that it contains an amine compound selected from amines, amine salts and quaternary ammonium salts.