JPH04103693A - Additive for coal-water slurry - Google Patents

Abstract

PURPOSE:To provide the subject additive containing a partially esterified product of a specific styrene/maleic acid copolymer, capable of stably dispersing coal powder in water at high concentration to form a dispersion having high fluidity and effective for suppressing the abrasion of especially a transportation pipe and a burner tip. CONSTITUTION:The objective additive contains a partially esterified product of a styrene/maleic acid copolymer produced by reacting (A) a styrene/maleic anhydride copolymer expressed by formula I ((l) is integer of 1-5; (m) is integer of 1-3; (n) is integer of 4-10), (B) a polyether derivative having a polyalkylene glycol chain and expressed by formula II (X is residue of a 1-4C compound having one active hydrogen atom; R is 3-8C alkylene oxide; (p) is integer of 0-10; (q) is integer of 10-200) and (C) a >=6C primary amine at molar ratios (A:B:C) of 1:(1-10):(1-3).

Description

Detailed Description of the Invention [Industrial Application Field 1] The present invention is an additive for coal-water slurry, specifically, a coal-water slurry additive for stably dispersing coal powder in water with good fluidity at a high concentration. The present invention relates to additives for slurries, and in particular to additives for coal-water slurries that reduce wear on transport pipes and burner tips.

[Prior art 1] In recent years, there has been concern about the depletion of petroleum resources, and coal is once again attracting attention as a substitute. however,
Since coal is a solid, there are problems such as complicated handling, environmental pollution due to scattering of coal dust when unloading at a port, and spontaneous combustion during coal storage.

Therefore, coal-water slurry (hereinafter referred to as rCWMJ), which is made by dispersing pulverized coal in water at a high concentration and turning it into a fluid, can be handled in the same way as oil, can be transported by pipeline, and has stable coal storage properties. This technology has been put into practical use in some areas as a direct combustion technology.

CWM is required to have a high concentration of dispersed pulverized coal and excellent fluidity and stability, and various additives have been developed to provide these characteristics.
When putting M into practical use, problems that were unthinkable at the testing stage in small-scale pilot plants have come to light.

For example, as additives for CWM, naphthalene sulfonate and its formalin condensate (Japanese Unexamined Patent Publication No. 5,621,636), polydicyclopentadine sulfonate (Japanese Unexamined Patent Publication No. 1983)
0 to 96689) and polystyrene sulfonate (
CWM using anionic additives such as those disclosed in Japanese Patent Application Laid-open No. 57-145187) poses a problem in practical use because pipelines and burner tips are subject to severe wear.

Also, alkylene oxide adducts of polyalkyleneimine (Japanese Patent Application Laid-open No. 58-49795) and polyether polyol type nonionic additives (Japanese Patent Application Laid-Open No. 57-56034)
Although the CWM using the above-mentioned CWM has relatively little wear, it has the disadvantage that when kept at high temperatures, the viscosity increases, making it impossible to transport by pipeline. Furthermore, the use of such additives (and CWM is insufficiently stable. For example, if left undisturbed for a month, the pulverized coal will settle and form agglomerates that have lost their self-flowing properties, making it impossible to discharge them from the storage tank. Become.

Saponified half ester of styrene-maleic acid copolymer (
JP-A No. 61-225284), since the parent wood group is only carboxylate, CWM using this additive is
It has poor dispersibility and cannot be highly concentrated.

In addition, salts of sulfonated styrene-maleic anhydride copolymer (JP-A-58-42694 and JP-A-61-22
1296) has poor stability.

[Problem to be Solved by the Invention 1] The purpose of the present invention is to provide an additive that has excellent concentration properties, fluidity, and dispersion stability, and enables the production of CWM with less wear on transport pipes. do.

[Means for solving the problem] The present invention comprises the following components (A), (B) and (C).
The present invention relates to an additive for coal-water slurry containing a partially esterified product of a styrene-maleic acid copolymer obtained by reacting components.

Component (A) is styrene represented by the following general formula (1).
It is a maleic anhydride copolymer.

(In the formula, Q represents 1-5, m represents an integer of 1 to 3, and n represents an integer of 4 to 10.) The copolymer may be either a random copolymer or a block copolymer. The number average molecular weight of the copolymer is 1000 to 9000, preferably 1500 to 30.
It is 00. In the above general formula (1), Q represents the number of styrene units and is an integer of 1 to 5, and m represents the number of maleic anhydride units and is an integer of 1 to 3, preferably Q/m
=3/1~]/1. n is 4 to 10, preferably 6
It is an integer of ~8.

Component (B) is a polyether M conductor having a polyalkylene glycol chain represented by the following general formula (2).

X(R)p(CzH+0)qH(2) (wherein, X is a residue of a compound having one active hydrogen having 1 to 4 carbon atoms, R is an alkylene oxide group having 3 to 8 carbon atoms, p Q represents an integer from 0 to 200) The polyether derivative imparts hydrophilicity to the partially esterified product of the styrene-maleic acid copolymer.

Examples of compounds having one active hydrogen having 1 to 4 carbon atoms include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol, allyl alcohol, and tert-butyl alcohol, carboxylic acids such as formic acid, acetic acid, and propionic acid, and methane. Examples include mercaptans such as thiol and ethanethiol. Above − Formula (2
), p represents the average number of moles of alkylene oxide added, and q represents the average number of moles of ethylene oxide added.

p is an integer of 0-10, preferably 0-5, and q is an integer of 10-200, preferably 20-150.

When q is less than 10, it is difficult to obtain a partially esterified water-soluble styrene-maleic acid copolymer, and when it exceeds 200, CW
The fluidity of M deteriorates.

Component (C) is a primary amine having 6 or more carbon atoms. The primary amine primarily binds with imide bonds to the styrene-maleic anhydride copolymer to provide hydrophobic groups. The primary amines of component (C) include amines having 6 or more carbon atoms, preferably 8 or more carbon atoms, such as aliphatic amines such as octylamine, laurylamine, and stearylamine, and those having unsaturated bonds such as oleylamine. Examples include aromatic amines such as aromatic amines, benzylamine, and aniline.

The reaction molar ratio of component (A), component (B) and component (C) is (A):(B):(C)=1:(1-10)+(1-3
).

The content of component (B) in the partially esterified product of the styrene-maleic acid copolymer of the present invention is 50 to 95% by weight, (
Component C) is preferably 2 to 20% by weight. (B
) component is less than 50% by weight, the partially esterified product of styrene-maleic acid copolymer is difficult to dissolve in water;
If the amount of component (C) is more than 2% by weight, the dispersibility of CWM is poor. If the component (C) is less than 2% by weight, the dispersibility of CWM is poor, and if it is more than 20% by weight, it is difficult to dissolve in water.

The reaction of component (A), component (B) and/or component (C) may be carried out under reflux in a solvent such as methyl ethyl ketone, methyl isobutyl ketone, dioxane, etc. The reaction can also be carried out at °C. The esterification reaction between component (A) and component (B) can be carried out without a catalyst, and a catalyst such as kill force or para-toluenesulfonic acid may be used. The same applies to the imidization reaction or amidation reaction between component (A) and component (C).

It is also possible to react components (A), (B) and (C) simultaneously.

The partially esterified styrene-maleic acid copolymer thus obtained leaves some carboxylic acids;
It can also be a salt of sodium, potassium, ammonium, etc.

The number average molecular weight of the partially esterified styrene-maleic acid copolymer thus produced is 5,000 to 5.
0,000, preferably 8,000 to 30,000. When the number average molecular weight is less than 5,000, the dispersion stability of the pulverized coal is poor and it tends to settle, while when it is greater than 50,000, it aggregates and loses its self-flowing properties.

The CWM additive of the present invention may be used in conjunction with other dispersants. Other dispersants that can be used in combination include salts of formalin condensates of naphthalene sulfonic acid, polymers of synchlopentadiene sulfonates, anionic dispersants such as polystyrene sulfonates, alkylphenol ethylene oxide adducts, and alkylphenol formalin condensates. Various dispersants may be mentioned, such as nonionic dispersants such as ethylene oxide adducts.

The amount of the CWM additive of the present invention to be used varies depending on the particle size of the coal, but when the particle size of the coal is 200 M/U80% by weight,
In the case of buses, usually 0°l to 2.0% by weight of coal powder,
Preferably it is 0.3 to 1.0% by weight.

The CWM additive of the present invention may be dissolved in water in advance and pulverized coal may be added thereto, or it may be added afterwards to a mixture of pulverized coal and water. Alternatively, as in the case of mixed pulverization, the coal may be added to the coal together with water at the same time as the coal is pulverized.

The coal powder to be slurried using the additive of the present invention has a particle size of 14 m or less, but is not limited thereto. Types of coal include various types of coal such as bituminous coal, sub-bituminous coal, lignite, etc., and coals from various production areas. The additive of the present invention can also be applied to coal that has been deashed by oil agglomeration, flotation, etc.

[Effect] The reason why the CWM additive of the present invention exhibits excellent effects is considered to be as follows. First, some of the additive dissolved in water is adsorbed onto the coal surface. Since the adsorbed additive is a polymer with several relatively long polyoxyethylene chains,
It is thought that the volume-limiting effect and osmotic pressure effect of the polymer work to produce a repulsive effect due to steric stabilization, and that the pulverized coal is dispersed and stabilized by the compressive repulsive effect of the polymer dissolved in water between the particles.

Furthermore, since this additive has some carboxyl groups, it also exhibits some anionic properties, and its dispersion is stabilized by the repulsive interaction between the electric double layer at the pulverized coal particle-water interface.

Furthermore, it is thought that the adsorbed polymer causes the pulverized coal to form a weak cohesive network structure, allowing it to maintain stability over a long period of time.

Regarding lubricity, it is thought that when the polymer molecules present in the water are compressed as the particles approach each other, a repulsive force is generated, which smoothes the sliding between the particles and reduces wear on the vibrator and burner tip.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples.

Examples 1 to 9 and Comparative Examples 1 and 2 Various additives were manufactured according to the formulations shown in Table 1.

A predetermined amount of additives (Table 2) and water were put into a 5001IIQ container and dissolved, and then Warkworth coal (Australian bituminous coal) pulverized to 80% by weight of 200 mesh pass was gradually added while stirring.

After mixing for 10 minutes after adding, mix at 4000 rpm with a homo mixer (“Auto Homo Mixer” manufactured by Tokushu Kikako Co., Ltd.)
and mixed for 10 minutes to prepare a coal-water slurry.

Table 2 shows the results of measuring the coal concentration, representative viscosity, and amount of sedimentation and agglomeration of the obtained coal-water slurry, and Table 3 shows the wear loss of the disk.

Each measurement was performed using the following method.

(1) Coal concentration (wt%): Determined from the amount of water loss on drying.

(2) Representative viscosity (IIIPa-5): Measure the rheogram with a "rheometer" manufactured by Haake Co., Ltd., and determine the viscosity at a slip rate of 1005 ec-'.

(3) Amount of sedimentation and flocculation (wt%) 2 coal-water slurry - 300
g was placed in a 250 mff pot, left as it was, and after 2 weeks, the pot was turned upside down and the amount remaining at the bottom of the pot without self-flowing was measured.

(4) Disc abrasion loss (+11 g) Put 500 g of two-coal-water slurry into a container, immerse a 5 (1+ TR〆 x 2) copper plate disk, and rotate it at 2000 rpm for 20 hours to reduce the abrasion loss of the disk. Find t2.

Comparative Examples 3 to 6 Coal-water slurries were prepared in the same manner as Examples 1 to 9 and Comparative Examples 1 and 2 using the additives shown in Table 1,
Coal concentration, representative viscosity, amount of sedimentation and flocculation, and disc wear loss were measured. The results are shown in Tables 2 and 3.

As is clear from the table, the coal-water slurry using the additive of the present invention has a high coal concentration, low viscosity and excellent fluidity and slurrying property, and is stable with a small amount of sedimentation and agglomeration. It can be seen that the disc has excellent lubricity, with little loss of wear due to disc wear.

[Effect of the invention] The additive for CWM of the present invention mainly contributes to the water reduction effect, and by using the additive, the pulverized coal concentration in CWM can be increased by 10 to 20% by weight compared to the conventional one. . In addition, it improves the fluidity of CWM and suppresses sedimentation and agglomeration of pulverized coal to maintain stability for a long time.It also improves the lubricity of CWM and reduces wear on transport pipes and burner tips. can.

Claims (1)

[Claims] 1. An additive for coal-water slurry containing a partially esterified styrene-maleic acid copolymer obtained by reacting the following components (A), (B) and (C): (A) Styrene-maleic anhydride copolymer represented by general formula (1) ▲ Numerical formulas, chemical formulas, tables, etc. are available ▼ (1) (In the formula, a is 1 to 5, m is 1 to 3, n is 4 to 10), (B) Polyether derivative X(R)p(C_2H_4O)qH(2) having a polyalkylene glycol chain represented by the general formula (2) (wherein, X represents a carbon atom number of 1 to (C) residue of a compound having one active hydrogen of 4, R is an alkylene oxide group having 3 to 8 carbon atoms, p is 0 to 10, and q is an integer of 10 to 200), (C) 6 carbon atoms The above primary amines. 2. The reaction molar ratio of each component (A), (B) and (C) is (A):(B):(C)=1:(1-10):(1-
3) The additive for coal-water slurry according to claim 1. 3. The number average molecular weight of the partially amide/imide and partially esterified styrene-maleic acid copolymer is 5000.
The additive for coal-water slurry according to claim 1, which has a molecular weight of 50,000 to 50,000.