JPS5849797A - Additive for coal-water slurry - Google Patents

Abstract

PURPOSE:An additive for providing highly concentrated coal-water slurry with stability in settling and stability to shearing, comprising a condensate (salt) of a specific phenol compound with formaldehyde as an active ingredient. CONSTITUTION:The desired additive comprising a condensate (a condensation degree of usually 1.2-3.0) of a compound shown by the formula[R is H, 1-22C alkyl, or alkenyl; AO is 2-4C oxyalkylene (>=60wt% oxyethylene); m is 1-100; n is 1 or 2) with formaldehyde, its alkali metal salt, ammonium salt, or lower amine salt as an active ingredient. Usually 0.01-5wt% (preferably 0.05-1.0wt%) additive is added to coal-water slurry.

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.

Due to its solid form, coal has long been the dominant fuel compared to petroleum. However, the oil crisis led to a review of coal, and coal has become a mixed fuel, as exemplified by coal-oil mixed fuel (COM). Many attempts have been 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 a separate slurry fuel.

In recent years, slurry, a fluid in which water is used as a medium and highly concentrated coal is dispersed, has been developed to be suitable for transportation by pipeline or oil tanker, and is also being used as an alternative fuel to oil in various boilers. Attempts are being made to do so. In the case of this slurry, since the medium is water, it is preferable that the slurry has the following properties.

In other words, it must have a high coal concentration, low viscosity, and excellent long-term stability without causing coal powder agglomeration or sedimentation.Also, it must be stable even when mechanical shearing force is applied. It is desirable that the slurry be able to maintain its stability.

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. For example, U.S. Pat.
Additives such as phosphoric acid esters, various amines, alkylene oxides and alkylphenols, naphthols, and other acidic phosphate salts disclosed in the above publications, and salts of polycarboxylic acids such as polymethacrylic acid, reduce viscosity. It has poor functionality and is difficult to obtain high concentration slurry.

In addition, the sulfonate of an oxyethylene adduct of an alkyl- or alkenyl-substituted phenol proposed in JP-A No. 56-20090 has a viscosity-lowering function compared to the above-mentioned additives, and contributes to the stability of the slurry to some extent. But,
There is still room for improvement in these properties, and there is a drawback that the stability of the obtained slurry is extremely reduced when mechanical shearing force is applied to it, so although it is still not satisfactory for practical use. There wasn't.

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 of this is the general formula of At least 60% by weight of the oxyalkylene groups are oxyethylene groups, m is 1 to ioo, n is 1
The present invention is an additive for coal-water slurry, which contains as an active ingredient a formaldehyde condensate of a compound represented by (an integer of 2 to 2) or its alkali metal salt, ammonium salt, or lower amine salt.

That is, according to the above-mentioned active ingredient of the present invention, it is possible to prepare a highly concentrated slurry due to its excellent viscosity reducing function, and for example, it is possible to easily obtain a coal-water slurry with a weight concentration of coal powder of 60 to 80% by weight. In addition, this slurry has excellent static stability with suppressed agglomeration and sedimentation during oral administration, and also has excellent stability against shearing force without becoming compacted even when subjected to mechanical shearing force. It becomes something.

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.

In this invention, the formaldehyde condensate of the compound represented by the above general formula can be produced by addition reaction of alkylene oxide to phenol, further sulfation, and then condensation reaction with formaldehyde, or by first condensation reaction of phenol with formaldehyde, and then It can be obtained by addition reaction of alkylene oxide and further sulfation.

In addition to phenol, the above-mentioned phenols include one alkyl group or alkenyl group having 1 to 22 carbon atoms in the aromatic ring.
Those having 1 to 2 are used, and typical examples thereof include hexylphenol, octylphenol, nonylphenol, and cyphthylphenol.

The alkylene oxide addition reaction and sulfation reaction can be carried out in the absence of a solvent or in the presence of a solvent by conventionally known methods. If using a solvent, ethane dichloride,
Chlorinated solvents that are inert to each reaction, such as carbon tetrachloride, are preferably used.

In the alkylene oxide addition reaction, ethylene oxide, propylene oxide, butylene oxide, etc. are used as the alkylene oxide, but ethylene oxide is particularly preferred. Further, a combination system of ethylene oxide and propylene oxide or butylene oxide is also preferred. In the case of a combination system, ethylene oxide is a small amount of all alkylene oxides (both are assumed to be 60% by weight).In addition, in the case of a combination system, the addition reaction may be carried out in blocks or randomly. The number of moles of these alkylene oxides added is 100 moles or less, preferably 60 moles or less, per mole of phenol.On the other hand, in the sulfation reaction, as a sulfating agent, for example, sulfuric anhydride, concentrated sulfuric acid, or fuming sulfuric acid is used. , chlorosulfonic acid and the like are preferably used.

As mentioned above, the formalin condensation reaction is carried out before or after the alkylene oxide addition reaction and sulfation reaction, but if it is carried out later and the above solvent is used in the alkylene oxide addition reaction or sulfation reaction, , the solvent is removed before formaldehyde condensation.

The reaction is carried out by a conventionally known method by adding formalin, that is, an aqueous formaldehyde solution, and heating and reacting with stirring. The degree of condensation resulting from this condensation reaction is usually 1.2 to 30, particularly preferably 1.2 to 10. If the degree of condensation is too low, the effects of this invention will not be sufficiently obtained, while if the degree of condensation is too high, the molecular weight will increase and the solubility in water will tend to decrease, causing problems in use.

In this invention, each of the formaldehyde condensates described above may be used as an active ingredient of the additive for coal-water slurry as is, or the condensates may be further neutralized with an alkali metal, ammonia, or a lower amine. Salt, ammonium salt or lower amine salt may be used as the active ingredient. By-products generated during the neutralization process can be removed, if necessary, by known methods such as rising or soap-Johning.

Examples of 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: Alkanol groups with 2 to 3 carbon atoms, such as monoethanolamine, jetanolamine, triethanolamine, monoisopropanolamine, diisopropanolamine, triisopropanolamine, and N-hydroxyethylethylenediamine. Amine; ethylenediamine, diethylenetriamine, triethylenetetramine, N-N-
There are salts of polyalkylene polyamines such as dimethylpropylene diamine; and 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, it varies depending on the particle size and concentration of the coal powder or the type of the active ingredient itself, but 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. The larger the amount added, the greater the viscosity-reducing effect and the better the stability. However, if the amount exceeds a certain amount, 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.

It should be noted that using the additive of this invention, it is not possible to obtain a stable slurry by simply performing underwater pulverization or ordinary impeller stirring (in some cases, a homogenizer with strong shearing force or a line mixer such as this stirrer may be used). It is best to mix it.

The coal to be applied to this invention may be sub-bituminous 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 prevent problems such as wear and blockage during pipeline transportation and burner combustion, 200 mesh passes are usually
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.

Examples Various phenols were subjected to an addition reaction with alkylene oxide, then sulfated using a sulfating agent, and then formalin was added dropwise in an aqueous solution under acidic sulfuric acid to perform a condensation reaction. By neutralizing with various bases, sample layer 1 shown in Table 1 below was obtained.
Seven kinds of additives for coal-water slurry of this invention consisting of .about.7 were obtained.

In Table 1, the numbers in parentheses indicate the number of moles of alkylene oxide added, and the numbers in parentheses indicate the degree of condensation. Also, a sample! 3.4.6 shows an example in which two types of alkylene oxides are used together in the alkylene oxide addition reaction.
) are block-like adducts that were subjected to addition reactions in the order shown in the table, and the latter (sample layer 6) is an example of a random-like adduct.

Table 1 Comparative Examples Sulfated polyoxyethylene (15) nonylphenol sodium salt (sample JFL8), sulfated polyoxyethylene (5) dibutylphenol sodium salt (sample i;
9), sulfated polyoxyethylene (3) hexyl alcohol sodium salt (sample layer 10), and sulfated polyoxyethylene (10) lauryl alcohol sodium salt (sample layer 11) were added to the coal-water mixture for comparison of this invention. It was used as an additive for slurry.

Note that the numerical value in parentheses in each sample indicates the number of moles of ethylene oxide added.

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 (produced in Japan) and Orchard Valley charcoal (produced in the United States) used in these four tests are as follows.

Miike Charcoal O+? Shi9-Charcoal specific moisture (wt%) 1.7 13.1 Ash
Minutes (wt%) 23.0 6.3 Volatile content (wt%) 38.0 33.2 Fixed carbon (wt%)
37.3 47.4 The viscosity (25°C) of the obtained coal-water slurry was measured using a B-type viscometer,
Static stability was investigated using the following method. That is, diameter 50,
6cI from the bottom of a stainless steel cylinder with a height of 20α
A take-out port with a stopper is provided at the +l and 12α positions, and the obtained coal-water slurry is poured from the bottom of the cylinder at 18
The temperature was filled to 0 and left at room temperature for one week. next,
Upper part above 12an' from the bottom of the cylinder, 6~
It was divided into a middle layer of 12 cm and a lower layer of 6 cm, and the solid content of each layer was measured by the loss on drying method of leaving it in a dry oven 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
C11, height 15 cI11 into a beaker 80
Insert it to the 0- line and install an impeller with a blade diameter of 2CI11 to 4
004 position, and stirred at 20 Orpm for 24 hours. After the stirring was stopped, the impeller was removed and left as it was for 3 days. After letting it stand 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 can be easily re-fluidized with a glass rod, etc. If a hard sediment is formed at the bottom, it can be washed out with a spatula, etc. ◎, ○, and × indicate cases where it cannot be taken out easily.
In the case of ◎ or ○, 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 2% by weight (including attached water). Next, 142.9 fI of an aqueous solution containing a predetermined amount of each of the additives of the above Examples and Comparative Examples was dissolved in a 1-inch beaker, and using a Homomixer M type manufactured by Tokushu Kika Kogyo Co., Ltd., 300 ~500rp
Coal powder 357.1 of the above while stirring slowly at m
Gradually add 9. After addition, increase the number of revolutions of the homomixer to 5. By stirring at QQQ' rpm for 10 minutes, a coal-water slurry having a solid content of 70% by weight was obtained.

The following Table 2 shows samples, &l
These are the results of Test Example 1 when Samples 8 to 11 were used as additives for Samples 8 to 7 and 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 all additives were not used, 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. , meaning it was impossible to measure.

Test Example 2 407v of Orchard Valley coal with a water content of 14% by weight, coarsely ground to a particle size of about 2mm, was placed in a ball mill with a capacity of 5 mm (ball filling rate: 30% by volume), and the above-mentioned additives were added to it in predetermined amounts. A dissolved aqueous solution 93y 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 3 shows sample layers 2 to 7 as additives of this invention.
and the results of Test Example 2 when Sample Layers 8 to 11 were used as additives in Comparative Examples.

In the table, the amounts of additives added, reference examples, and (*) are shown in the second section.
The same is true for tables.

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. I can see that it will be carried away.

Claims (1)

[Claims] (1) The following general formula; (wherein R is a hydrogen atom, an alkyl group or alkenyl group having 1 to 22 carbon atoms, AO is an oxyalkylene group having 2 to 4 carbon atoms, and at least 60% by weight of all oxyalkylene groups) % is an oxyethylene group, m is 1 to 100, n is 1
An additive for coal-water slurry, which contains as an active ingredient a formaldehyde condensate of a compound represented by (an integer of 2 to 2) or an alkali metal salt, ammonium salt or lower amine salt thereof.