JPS59152995A - Additive for coal and water slurry - Google Patents

Abstract

PURPOSE:Additive for coal and water slurry for dispersing coal powder into water stably in high concentration, containing a (co)polymer of a specific olefinic monomer. CONSTITUTION:The desired additive containing a polymer consisting of a repeating unit shown by the formula [R<1> and R<2> are H, F, Cl, Br, I, 1-4C alkyl, or phenyl; X is COOM ; Y is COOM', or CONR<3>R<4> (M and M' are alkali metal, ammonium, etc.; R<3> and R<4> are H, 1-22C alkyl, alkenyl, etc.)] as an active ingredient. The polymer is obtained by (co)polymerizing an olefinic carboxylic acid (amide, anhydride, ester), etc., followed by operations such as neutralization, hydrolyzing, amidation, etc., and has usually 400-50,000 (preferably 500-20,000) number-average molecular weight.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an additive for coal-water slurry for stably dispersing coal powder in water at a high concentration.

Due to its solid form, coal had long been supplanted as a fuel by petroleum, but the oil crisis led to a review of coal, and as exemplified by coal-oil mixed fuel (COM), Many attempts are being made to treat coal as a fluid by turning it into powder and mixing it with a medium.

However, in the case of coal-oil mixed fuel, it is impossible to avoid the disadvantage that about half of the fuel is oil, and there is a desire to develop another slurry fuel.

In recent years, attempts have been made to use water as a medium to create slurry as a fluid in which coal is dispersed at a high concentration, making it suitable for transportation by pipeline or oil tanker, and furthermore, attempting to use it as an alternative fuel to oil in various boilers. Attempts are being made. In the case of this slurry, since the medium is water, it is preferable that the slurry has the following properties.

That is, it must have a high coal concentration and low viscosity, and it must also have excellent long-term stability without causing coal powder collection or sedimentation.

By the way, in order to improve the characteristics of coal-water slurry,
It is already known to add various additives such as rust preventives, antioxidants, and dispersants to slurries. However, among these known additives, there are hardly any that give very good results on coal concentration or viscosity and satisfy both this property and the stability of the slurry. for example,
U.S. Patent No. 2,346.151, Japanese Patent Publication No. 1983-
Phosphate esters, various amines, reaction products of alkylene oxides with alkylphenols, naphthols, and other acidic phosphates, and polycarboxylic acids such as polymethacrylic acid disclosed in Japanese Patent Application Laid-open No. 45600 and Japanese Patent Application Laid-open No. 16511/1983. Additives such as salt have poor viscosity lowering properties and are difficult to obtain highly concentrated slurries. Additionally, additives such as fatty acid metal salts disclosed in U.S. Pat. It tends to cause sedimentation (it has the disadvantage of poor long-term stability).

As a result of intensive studies to obtain a coal-water slurry that satisfies the required properties as described in "2," the inventors discovered that by adding a specific polymer as an additive to the coal-water slurry, a high concentration The inventors discovered that it is possible to obtain a coal-water slurry that has a large, low viscosity and excellent long-term stability, leading to the creation of this invention.

That is, the present invention relates to an additive for coal-water slurry containing as an active ingredient a polymer consisting of repeating units represented by the following general formula (where k and R are hydrogen atoms, fluorine atoms, chlorine atoms). Atom, bromine atom, iodine atom, alkyl group having 1 to 4 carbon atoms, or phenyl group, which may be the same or different, X is C00M, Y is COOM
'or CON R3R', M is an alkali metal,
Ammonium group 2 Morpholinium group or carbon number 1-4
an ammonium group having 1 to 3 alkyl groups or hydroxyalkyl groups having 1 to 4 carbon atoms, M is a hydrogen atom, an alkali metal, an ammonium group, 1 morpholinium group, an alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms; In the ammonium group having 1 to 3 hydroxyalkyl groups, - and 1 are hydrogen atoms, alkyl groups or alkenyl groups having 1 to 22 carbon atoms, or hydroxyalkyl groups having 1 to 4 carbon atoms. ) The additive for coal-water slurry of the present invention has a large viscosity-reducing function and enables the preparation of a highly concentrated slurry. For example, a coal-water slurry with a high concentration of 65 to 80% by weight of coal powder can be easily obtained. At the same time, this slurry has excellent long-term stability with less agglomeration and sedimentation over time. Therefore, the coal-water slurry prepared using the additive of the present invention has advantages such as being easy and economical to transport by pipeline or other means, and being easily supplied to combustion equipment.

The polymer which is the active ingredient in this invention may contain one type of repeating unit, or may contain two or more types of repeating units.

This polymer is obtained by homopolymerizing one kind of corresponding olefinic monomer or copolymerizing two or more kinds, and also contains olefinic carboxylic acid, olefinic carboxylic acid amide,
It can be obtained by polymerizing or copolymerizing olefinic carboxylic acid anhydrides, olefinic carboxylic esters, etc., and then performing operations such as neutralization, hydrolysis, and amidation.

The polymerization reaction can be carried out using a radical initiator such as a peroxide, and in the case of an olefinic carboxylic acid ester such as diethyl fumarate, a polymer having a number average molecular weight of 20,000 or more can be obtained.

Olefinic carboxylic acids used in polymerization include maleic acid, fumaric acid, chloromaleic acid, dichloromaleic acid, phenylmaleic acid, citraconic acid, etc. Olefinic carboxylic acid anhydrides are acid anhydrides of these carboxylic acids. The olefinic carboxylic acid esters are esters of these carboxylic acids and alcohols having 1 to 4 carbon atoms.

For polymers of olefinic carboxylic acids and olefinic carboxylic acid amides, half or more of the carboxyl groups are neutralized using a basic substance.

The basic substance used for neutralization is lithium.

hydroxides of alkali metals such as sodium and potassium;
Carbonates monobicarbonate; ammonia; primary amines such as methylamine, ethylamine, propylamine, butylamine, monoethanolamine, monoisopropaturamine; dimethylamine.

diethylamine, dipropylamine, dibutylamine,
Secondary amines such as jetanolamine, diisopropanolamine, morpholine: trimethylamine, triethylamine, tripropylamine, tributylamine, triethanolamine.

There are tertiary amines such as triisopropanolamine.

Polymers of olefinic carboxylic acid anhydrides and olefinic carboxylic esters are made into a form in which half or more of the carboxyl groups are neutralized after hydrolysis or amidation reaction with ammonia or amine. The amine used in the amidation reaction is a primary or secondary amine having an alkyl or alkenyl group having 1 to 22 carbon atoms.

The number average molecular weight of the polymer used as an additive in this invention is 400.
50,000 to 50,000, preferably 500 to 20,000.

The additive in this invention is selected from one or more of the above polymers and used as is or with water.

It is used dissolved or dispersed in alcohol, hydrocarbon, etc.

Such additives may include known slurry additives such as gelling agents, rust preventives, and preservatives, if necessary.

The amount added to the coal-water slurry varies depending on the characteristics of the slurry, such as the particle size and concentration of the coal powder, the type of the active ingredient itself, etc., but in general, the amount of the active ingredient is
0.01 to 5% by weight in the slurry, particularly preferably 0.0
The content is preferably 5 to 0.5% by weight. As the amount added increases, the viscosity lowering effect becomes greater and better results are obtained in terms of stability. However, if the amount exceeds a certain level, no further effect can be expected, which is economically disadvantageous.

The addition method is arbitrary, and an appropriate method may be selected depending on whether the coal powder is obtained by dry pulverization or wet pulverization. For example, in the dry pulverization method, it is preferable to add and mix the additive of the present invention in advance into water in which the pulverized powder is to be dispersed, and then add and mix the pulverized powder thereto. On the other hand, in the wet pulverization method, it may be added in advance to the water used for wet pulverization, or it may be added during wet pulverization or after each pulverization.

In addition, if it is difficult to obtain a stable slurry using the additive of this invention by submerged pulverization or ordinary impeller stirring, mixing may be performed using a stirrer with strong shearing force such as a homogenizer or line mixer. It is better to do so.

The coal applicable to this invention may be subbituminous coal, bituminous coal, anthracite coal, etc., and is not particularly limited. Also,
This coal is pulverized by a dry pulverization method or a wet pulverization method to obtain a powder for water slurry, but the particle size of this powder is not particularly specified.

However, in order to prevent problems such as wear and blockage during pipeline transportation and burner combustion, the
It is preferable that the mesh pass is 50% by weight or more, and 7
It is more preferable if it is 0% by weight or more.

Next, examples of the present invention will be described in more detail.

Example 1 After sufficiently purging the fourth flask with a stirrer in No. 11 with nitrogen, 98 g of maleic anhydride, 392 g-b of benzene, and 9.8 g of benzoyl peroxide were added, and the temperature was raised to 80° C. while introducing nitrogen gas. Stirring was continued for 20 hours.

Next, the precipitate was filtered to obtain 22.5 g of crude polymaleic anhydride. This was dissolved in 100% acetone, and then added dropwise into 11% benzene to obtain 20°Og of purified polymaleic anhydride. The analytical values of this purified polymaleic anhydride are shown below.

Infrared absorption spectrum 1850(1)-1178
5cm-1 Elemental analysis value C: 46.0% (calculated value: 48.9%
) H2 2.9% (calculated value: 2.0%) Number average molecular weight 850 (vapor pressure equilibrium method) This purified maleic anhydride 5
g was dissolved in 45 g of hot water, and then neutralized using a 48% caustic soda aqueous solution to obtain an aqueous solution of sodium polymaleate (sample/l 62).

Example 2 After dissolving 5.0 g of the purified polymaleic anhydride obtained in Example 1 in 50 g of dioxane, a solution of 9.3 g of dodecylamine dissolved in 50 g of dioxane was added to the solution at 80°C.
The mixture was added dropwise over time, and stirring was continued for an additional 3 hours. Next, this reaction solution was mixed with 2.000% of benzene. ,/ to obtain purified polydodecyl maleamic acid. The analytical values are shown below.

Infrared absorption spectrum 1.680cm" (NH group of amide) 1550c+n" (same) 2800-3300α-1 (C=Q group of amide) Elemental analysis value C: 69.8% (calculated value 67.8%) H: 11.5%
(Calculated value 10.2%) N: 4.8% (Calculated value 4.
9%) Number average molecule H2, ooo (vapor pressure equilibrium method) After dissolving 5 g of this purified polydodecyl maleamic acid in 50% methanol, it was neutralized using a 10% aqueous methanol solution to obtain polydodecyl maleamic acid. potassium acid (sample/l
A solution of 63) was obtained.

Example 3 After thoroughly purging a four-bottle flask with a stirrer with nitrogen, 150 g of diethyl fumarate and 1 soy of luene were added.
b and 15 g of azobisisobutyronitrile were added, and stirring was continued at 60° C. for 10 hours while introducing nitrogen gas. This reaction solution was then added dropwise to 5,000 ml of hexane to obtain 92 g of purified polydiethyl fumarate. The analytical values are shown below.

Elemental analysis value C: 54.5% (calculated value = 55.8%) T-1:
7.3X (calculated value near, 0%) then 500 ml
20g of purified polydiethyl fumarate in the fourth flask.
and 20 Q ml of water were added, and 1.0 g of sulfuric acid was added thereto, followed by heating at 60° C. for 5 hours.

The reaction system was then heated for 1 hour under a reduced pressure of 50+++ mT (g), and the produced ethanol was distilled off together with water to obtain a concentrated aqueous solution of polyfumaric acid. was added dropwise to obtain purified polyfumaric acid.The analytical values are shown below.

Infrared absorption spectrum 2500-3100 cm' (COOH group) Elemental analysis C: 40.5% (calculated value: 41.4%) H: 3.3%
(Calculated value: 3.4%) Number average molecular weight 15,000 (Vapor pressure equilibrium method) This purified polyfumaric acid was neutralized using a caustic soda aqueous solution in the same manner as in Example 1, and sodium polyfumarate (sample 45) was An aqueous solution was obtained.

Examples 4 to 10 Samples for use as additives for coal-water slurries of the present invention were obtained in the same manner as shown in the previous examples.

Table 1 shows the samples obtained in the following examples.

In Table 1, MW means number average molecular weight.

Table 1 Comparative Examples Samples/1611 to 13 shown in Table 2 below were each used as an additive for coal-water slurry different from the present invention. Note that Mw means number average molecular weight.

Coal-water slurry was actually prepared according to Test Examples 1 and 2 below using the additives of the above examples and comparative examples, and the viscosity (258C) and stability of this slurry were investigated. The industrial analysis values of Datong coal (produced in China) and Lithgow coal (produced in Australia) used in this test were as follows.

Daido coal Lithgow coal moisture (%) 3.5 3.0 Ash content (%) 12.3 10.3 Volatile content (%) 28.4 33.6 Fixed carbon (%) 5
9.3 56.7 The viscosity (25° C.) of the obtained coal-water slurry was measured using a B-type viscometer, and the stability was examined by the method of Haggi. That is, diameter 5cm, height 2o
6cm and 12cm from the bottom of crn's stainless steel cylinder
An outlet with a stopper is provided at position α, and the obtained coal-
The water slurry was poured into the cylinder to a depth of 18 crn from the bottom and allowed to stand at room temperature for 2 weeks. Next, the cylinder is divided into an upper layer above 12 cm from the bottom, a middle layer between 6 to 12 c++, and a lower layer below 6 crh, and the solid content of each layer is removed by a loss-on-drying method in which the solid content is left in a dryer at 105°C for 1 hour. It was measured.

Test Example 1 Daedong coal was dry-pulverized to obtain coal powder containing 70 parts by weight of 20o mesh pass. The moisture content of this powder was 4% by weight. Next, 135°4 g of an aqueous solution containing a predetermined amount of each of the additives of Examples and Comparative Examples was placed in a beaker of IA', and mixed at 300 to 500 rpm using a homomixer M type manufactured by Tokushu Kika Kogyo Co., Ltd. While stirring slowly, 364.6 g of the above coal powder was gradually added, and after the addition was completed, the rotation speed of the homomixer was increased to 5,000 rPm and 1
By stirring for 0 minutes, coal with a solid content of 70% by weight -
A water slurry was obtained.

Table 3 below shows the test results when Samples/161-10 (Examples) and 11-13 (Comparative Examples) were used as additives. This is the result when not used. The amount added is the proportion of the additive in the slurry.

Moreover, (x1) in the table means that the slurry could not be taken out from the take-out port of the cylinder because the viscosity of the slurry was so high that it was impossible to measure it. Also,
(x2) means that the coal powder completely settled during the test and could not be taken out from the cylinder as above, making it impossible to measure.

Table 3 Test Example 2 Capacity 5I! Lithgow coal with a total moisture content of 8% by weight, coarsely ground to a particle size of approximately 21mm, was placed in a ball mill (ball filling rate: 30% by volume) at 391mm. 108.7 g of an aqueous solution containing a predetermined amount of the additives of the Examples and Comparative Examples was added thereto, and the mixture was stirred for 30 minutes to reduce the particle size of the coal powder to 2.
00 mesh pass 68% solids content 72% by weight
A coal-water slurry was obtained.

The following Table 4 shows sample/462.3°5.
6.9 (Example) and 13 (Comparative Example) were used. In addition, sample All, 12
When the additive (comparative example) was used, the viscosity was so high that it had to be scraped out with a spatula when taking it out from the ball mill, just like when no additive was used at all. Therefore, viscosity measurement or stability test did not do so.

Further, the amounts added in the table are the same as above, and (x) means that the coal powder completely settled during the test and could not be taken out from the cylinder, making it impossible to measure.

As is clear from the test results in Table 4 and above, by using the additive of the present invention, a homogeneous coal-water slurry with high concentration, low viscosity, and excellent long-term stability can be obtained. I understand.

Patent applicant: NOF Corporation

Claims (1)

[Claims] (1) An additive for coal-water slurry containing as an active ingredient a polymer consisting of repeating units represented by the following general formula. (However, kl and R2 are a hydrogen atom, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an alkyl group having 1 to 4 carbon atoms, or a phenyl group, and may be the same or different, and
is C00M, Y is COOM' or C0NR"R', M is an alkali metal, an ammonium group, 1 morpholinium group, an alkyl group having 1 to 4 carbon atoms, or an alkyl group having 1 to 4 carbon atoms.
~4 hydroxyalkyl group −′ ammonium group having 1 to 3 4 atoms, M′ is a hydrogen atom,
Alkali metal, ammonium group 1 morpholinium group or ammonium group having 1 to 3 alkyl groups having 1 to 4 carbon atoms or hydroxyalkyl groups having 1 to 4 carbon atoms B
3 and 4 are a hydrogen atom, an alkyl group or alkenyl group having 1 to 22 carbon atoms, or a hydroxyalkyl group having 1 to 4 carbon atoms. )