JPS5834896A - Additive for coal/water slurry - Google Patents

Abstract

PURPOSE:The titled additive giving a highly conc. slurry excellent in standing stability and shear stability, which contains as an effective component a condensate between a mixt. of naphthalenesulfonic acid with a lignin deriv. and formaldehyde, or its salt. CONSTITUTION:An additive for a coal/water slurry contg. as an effective component a condensate between a mixt. of naphthalenesulfonic acid with a lignin deriv. such as lignin or ligninsulfonic acid and formaldehyde or its alkalimetal salt, ammonium salt or lower amine salt such as methylamine or triethanolamine. The additive is effective in such an amt. that a slurry contains about 0.01-5wt% effective component. A high-conc. and low-viscosity, homogeneous coal/water slurry with excellent standing stability and shear stability, is obtd.

Description

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

Because coal is solid in shape, it had long lost its place as a fuel to petroleum, but in the wake of the oil crisis, coal was reconsidered, and coal-oil mixed fuel (COM-F) was used.
! As shown in +, 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 drawback 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 should have a high coal concentration and low viscosity, and should also have excellent long-term stability without causing coal powder agglomeration or sedimentation. It is also desired that the slurry be able to maintain its stability even when mechanical shearing force is applied.

By the way, it is already known that various additives such as rust preventives, antioxidants, and dispersants are added to the slurry in order to modify the characteristics of the coal-water slurry. 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. Examples include U.S. Pat.
Additives such as phosphoric acid esters, various amines, reactants of alkylene oxides with alkylphenols, naphthols, and other acidic phosphates, and salts of polycarboxylic acids such as polymethacrylic acid disclosed in the above publications have a viscosity-lowering function. It is difficult to obtain highly concentrated slurry.

Also, JP-A-52-71506 and JP-A-53-5
The lignin sulfonate proposed in Publication No. 81, the naphthalene sulfonate salt proposed in JP-A-56-21636, and the salt of formaldehyde condensate of naphthalene sulfonic acid have lower viscosity than the above-mentioned additives. Although it has some functions and contributes to the stability of the slurry, there is still room for improvement in these properties, and the disadvantage is that when mechanical shearing force is applied to the resulting slurry, its stability decreases dramatically. Therefore, it could not be said to be satisfactory for practical use.

The present invention aims to provide an industrially useful additive that has an improved viscosity-reducing function compared to the above-mentioned proposals and also provides good results in the standing stability and stability against shearing forces of slurry. The gist is that coal-water slurry I contains a formaldehyde condensate of a mixture of naphthalene sulfonic acid and a lignin derivative, or its alkali metal salt, ammonium salt, or lower amine salt as an active ingredient.
It is in additives for J-.

That is, unlike the salt of the formaldehyde condensate of naphthalene sulfonic acid alone as proposed above, the additive of the present invention contains a formaldehyde condensate of a mixture of the sulfonic acid and a lignin derivative or a salt thereof as an active ingredient. According to such an active ingredient, it is possible to prepare a highly concentrated slurry due to its excellent viscosity-lowering ability.
Water slurry can be easily obtained, and this slurry has excellent static stability with reduced agglomeration and sedimentation over time, while being compactable even when subjected to mechanical shearing force. It also has excellent stability against shearing forces.

Slurry with excellent stability against shear forces would be manufactured overseas and transported by long-distance pipelines or ships for long periods of time before being consumed in Japan. This is very advantageous because it can maintain sufficient stability of the slurry. in this way,
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 methods, and being easily supplied to combustion equipment.

The formaldehyde combination of a mixture of naphthalene sulfonic acid and a lignin derivative in the present invention can be easily obtained according to a conventionally known method, such as the method described in Japanese Patent Publication No. 52-25433. For example, in the first step, sulfuric acid and water are added to naphthalene sulfonic acid, heated to a predetermined temperature, and then a 37% formaldehyde aqueous solution, that is, formalin, is gradually added dropwise, and in the second step, An aqueous slurry solution of formalin and a lignin derivative is added under conditions of slightly elevated temperature to carry out a condensation reaction until a predetermined degree of condensation is obtained.

Lignin derivatives used in this condensation reaction include lignin and lignin sulfonic acid.

The ratio of the lignin derivative to naphthalene sulfonic acid is usually 5 to 30 parts by weight, preferably 10 parts by weight, per 100 parts by weight of naphthalene sulfonic acid.
It is preferable that the amount is 20 parts by weight. If the proportion of the lignin derivative used is too small, it will be difficult to obtain the effects of this invention, and in particular, the stability against shear force will not be improved. On the other hand, if the amount is too large, insoluble precipitates are generated during the reaction, which tends to lower the overall degree of condensation, which is not preferable.

In this invention, the above formaldehyde condensate may be used as an active ingredient of the additive for coal-water slurry as it is, or this condensate may be further neutralized with an alkali metal, ammonia or a lower amine to form an alkali metal salt. , ammonium salts or lower amine salts, and these salts may be used as active ingredients. By-products generated during the neutralization process can be removed by known methods such as liming and soap-Johning, if necessary.

The alkali metal salts include lithium salts, sodium salts, and potassium salts. In addition, lower amine salts include alkyl groups having 1 to 4 carbon atoms such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, propylamine, dipropylamine, tripropylamine, butylamine, dibutylamine, and tributylamine. Amines with 2 to 3 carbon atoms, such as monoethanolamine, jetanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, N-hydroxyethylethylene diamine, etc.
Amines with alkanol groups; ethylenediamine, diethylenetriamine, triethylenetetramine, N・N
- Polyalkylene polyamines such as dimethylpropylene diamine - Salts of cyclic amines such as morpholine and piperidine.

In this invention, one or more of the above-mentioned active ingredients can be selected and used as is or in a state of being included in a medium such as water, alcohol, or hydrocarbon. . Such additives include
If necessary, known slurry additives such as gelling agents, rust preventives, and preservatives may be included.

The amount added to the coal-water slurry depends on its slurry characteristics,
In other words, although it varies depending on the particle size and concentration of coal powder or the type of active ingredient itself, generally the active ingredient is 90.01 to 5% by weight of the slurry, particularly preferably 0.05% by weight.
It is preferable to adjust the amount to 1.0% 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 underwater pulverization or normal impeller stirring, use a stirrer with strong shearing force such as a homogenizer or line mixer. Better to mix.

The coal to be applied to this invention may be subbituminous coal, bituminous coal, anthracite coal, etc., and is not particularly limited, but coal with fewer pores is preferable. In addition, this coal is pulverized using dry or wet pulverization methods to produce powder for water slurry.
The particle size of this powder is also not particularly specified. However, in order to avoid problems such as wear and blockage during pipeline transportation and burner combustion, usually 200 mesh passes or 5
It is preferably 0% by weight or more, and more preferably 70% by weight or more.

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

Example 100 parts by weight of naphthalenesulfonic acid, 98% by weight of sulfuric acid 3
A mixture consisting of 5 parts by weight and 21 parts by weight of water was
The mixture was heated to 0°C, and 62 parts by weight of formalin was added dropwise over 2 hours. Then, a slurry consisting of 20 parts by weight of lignin and 40 parts by weight of formalin was added in four portions every hour, and the mixture was stirred at 95 to 100° C. for 14 hours to carry out a condensation reaction.

The formaldehyde condensate thus obtained was used as an additive for coal-water slurry (Sample No. 1) of the present invention.

In addition, the sodium salt (
sample 2), ammonium salt of formaldehyde condensate obtained by neutralization with ammonia (sample blood 3), and triethanolamine salt of formaldehyde condensate obtained by neutralization with triethanolamine (sample blood 3); 4)
were used as the additives for coal-water slurry of the present invention. Incidentally, by-products during the neutralization treatment were removed by appropriate means such as cooling.

Comparative Examples Sodium salt of formaldehyde condensate of naphthalene sulfonic acid (sample 5), sodium salt of lignin sulfonic acid (sample 6), and a mixture of sample 5 and lignin at a solid content ratio of 4:1 (sample 7) ) was used as a comparative coal-water slurry additive for this invention.

Using each of the additives in the above examples and comparative examples, a coal-water slurry was actually prepared according to Test Examples 1 and 2 below,
The influence of the viscosity (25° C.), static stability, and stability due to shear force of this slurry was investigated. The industrial analysis values of Miike charcoal (made in Japan) and Orchard Valley charcoal (American dust) used in this test are as follows.

Intrinsic moisture (wt%) 1.7 13.1 Ash content (wt%) 23.0 6.3 Volatile content (wt%) 38.0 33.2 Fixed carbon (
Weight %) 37.3 47.4 The viscosity (25° C.) of the obtained coal-water slurry was measured using a B total viscometer, and the stationary stability was examined using the following method. That is,
A stoppered outlet is provided at positions 6a and 12a from the bottom of the stainless steel cylinder with a diameter of 5 mm and a height of 2 degrees.
The obtained coal-water slurry was poured into the cylinder from the bottom to the 18th side, and allowed to stand at room temperature for one week. Next, from the bottom of the cylinder to the upper part above 12 parts, 6~
Divided into the middle part of 12- and the lower part below 6c,
The solid content of each layer was measured by the loss-on-drying method of leaving the layer in a drying mold at 105° C. for 1 hour.

In addition, stability due to shear force was determined by the following method. That is, the obtained coal-water slurry was
The mixture was placed into 11 beakers with a height of 15 mm and a height of 15 mm up to the 800 y line, an impeller with a blade diameter of 2 mm was set at a position of 400 d, and the mixture was stirred at 200 rpm for 24 hours. After the stirring was stopped, the impeller was removed and left as it was for 3 days. After standing for 3 days, tilt the beaker to pour out the slurry. If all of the slurry flows out, it will remain at the bottom, but if it can be easily re-fluidized with a glass rod, etc., a hard sediment will form at the bottom, and it will be easy to use a spatula, etc. Cases in which the slurry could not be taken out were represented by ◎, ◎, and ×, respectively, and in the case of ◎ and ○, it was determined that a slurry strong against shearing force was obtained.

Test example 1 Miike charcoal is dry crushed to give 70% by weight of 200 mesh charcoal
of coal powder was obtained. The moisture content of this powder was 4% by weight (including attached water). Next, a 135.4F aqueous solution containing a predetermined amount of each of the additives of the Examples and Comparative Examples was dissolved in a beaker No. 11, and using a Homomixer M type manufactured by Tokushu Kika Kogyo ■, 300 to so Gradually add the above coal powder 364.6F while stirring slowly at rpm, and after the addition is complete, increase the rotation speed of the homomixer to 5.
By raising the temperature to 00 Orpm and stirring for 10 minutes,
A coal-water slurry with a solid content of 70% by weight was obtained.

The following Table 1 shows sample sizes 1 to 4 as additives of this invention.
and the results of Test Example 1 when Samples 11m5 to 7 were used as additives in Comparative Examples. In the table, the amount added is expressed as the proportion of the additive (solid content) in the slurry. In addition, the reference example is the result when no additive was used at all, and (*) in the table indicates that the slurry cannot be taken out from the cylinder outlet because the viscosity of the slurry is extremely high. This means that it was impossible to measure.

Orchard Valley Coal 407y with a moisture content of 14% by weight, coarsely pulverized to a particle size of 2 m, was placed in a ball mill C ball filling rate of 30 vol. was added and stirred for 30 minutes to obtain a coal-water slurry with a solid content of 70% by weight and a coal powder particle size of 200 mesh pass 80% by weight.

The following Table 2 shows the results of Test Example 2 when Sample Group 2 was used as the additive of the present invention and Samples Na5 to 7 were used as the additives of the comparative examples. In the table, the amounts of additives added, reference examples, and (*) are the same as in Table 1.

As is clear from the above test results, by using the additive of the present invention, a homogeneous coal-water slurry with high concentration, low viscosity, and excellent static stability and stability against shear force can be produced. It turns out that you can get it.

Patent applicant: NOF Corporation

Claims (1)

[Claims] (1) An additive for coal-water slurry containing a formaldehyde condensate of a mixture of naphthalene sulfonic acid and a lignin derivative, or its alkali metal salt, ammonium salt, or lower amine salt as an active ingredient.