JPS61258895A - Concentrated coal/water slurry composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having low viscosity, transportable as easily as fuel oil and combustible by a fuel oil burner, by suspending fine coal powder in an aqueous medium in the presence of a specific compound having plural polyalkyl ether chains and a higher fatty acid, etc. CONSTITUTION:The objective composition can be produced by suspending fine coal powder (the particles finer than 74mu in diameter account for >=80% of the whole coal powder) in water containing (A) a compound having plural polyalkyl ether chains and a molecular weight of preferably 20,000-50,000 and obtained by the polyalkyl etherification of an aliphatic compound having two or more active hydrogen atoms and (B) >=8C fatty acid (e.g. coconut oil acid) or higher alcohol. The additive A can be produced e.g. by the addition polymerization of an OH-containing compound such as ethylene glycol or an amine compound such as methylamine to ethylene oxide. The ratio of the addi tive A to B is preferably 5:5-9:1, and the total amount of the additives in the slurry is preferably 0.1-1.0wt%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a coal/water slurry composition that has low viscosity and excellent fluidity despite having a high coal concentration.

[Conventional technology]

Demand for coal has been steadily expanding, driven by rising oil prices and advances in solids handling technology. Since coal as an energy source is solid, it is necessary to consider its handling costs, and at present, there is also the cost of transporting it.

Compared to petroleum, which can be handled on a large scale by ports, demand is expected to increase in areas with cost advantages. Handling coal in fine powder form is being considered as a method similar to handling coal as a fluid, but in the case of coal powder, it is necessary to take measures to prevent spontaneous combustion and dust explosions. Therefore, coal powder in oil.

Techniques for using water in methanol and water have been developed and considered.Among these media, it is obvious that the method of using water is more advantageous from a cost perspective, and recent research on the development of advanced coal utilization has been conducted. The main component is coal/water slurry.

Although coal has hydrophilic groups such as hydroxyl and carboxylic acid groups in its molecules, it is hydrophobic as a whole, and if a large amount of this fine powder is present in water, it will aggregate due to hydrophobic bonds. The viscosity increases and the fluidity decreases significantly. Therefore, at present, slurry having a maximum coal concentration of about 60% can only be obtained.

In order for coal/water slurry to work effectively as a fuel,
Taking into account the latent heat of vaporization of water, a coal concentration of at least 70% or more is generally desired. To achieve this, additives are used to physically improve the fine particle distribution of coal, and chemically to intervene between coal and water to maintain coal dispersion and improve fluidity. It is being considered.

[Problem that the invention seeks to solve]

Preparation of highly concentrated coal/water slurry using additives requires that the additive cost increases the total cost of the slurry.
There is no point in eliminating the cost advantage as a petroleum substitute, and therefore it is required to obtain the desired slurry at low cost or with a low additive amount.

The present invention satisfies this requirement and provides a coal/water slurry that can be transported in bulk and burned in a heavy oil burner.

[Means for solving problems]

According to the present invention, a highly concentrated coal/water slurry composition is provided in which at least 60% by weight of coal is finely suspended at low viscosity in an aqueous medium in the presence of the following compounds A and B.

Compound A: A compound having a plurality of polyalkyl ether chains obtained by polyalkyl etherification of an aliphatic compound having two or more active hydrogens.

Compound B: Fatty acid or higher alcohol having 8 or more carbon atoms.

Additives that have been considered for use in the past for the purpose of obtaining high-concentration coal/water slurry include lignin sulfonate (Japanese Patent Laid-Open No. 57-96090), polycyclic aromatic sulfonate formalin condensate (Japanese Patent Laid-open No. 57-96090), 57-145193), or polyether compounds similar to the present invention (JP-A-57-102
994) etc. are clearly indicated. However, in order to obtain a satisfactory effect, these additives require adjustment of the particle size distribution and a relatively high addition amount, and their fluidity is still insufficient. In order to put highly concentrated coal/water slurry into practical use as a petroleum alternative fuel, it is desirable that the fluidity, or viscosity, be similar to that of heavy oil, and at the same time, the fine coal powder can be dispersed in water as an additive. It is important to have a viscosity reducing effect in order to increase fluidity. Based on this idea, a product containing a fatty acid ester of a polyether compound obtained by addition polymerizing an alkylene oxide to a polyamine similar to the present invention, and an aliphatic alcohol, a nrubitan fatty acid ester, or a silicone compound as a second component ( JP-A-59-145292) etc. are clearly disclosed. How the compounds disclosed herein act on coal/water systems;
Regarding whether it imparts dispersion or fluidity, it is believed that the polyether compound, one of the two components, adsorbs to the coal and imparts hydrophilicity, and the effect of the second component is not specified. .

The present inventors conducted a comparative study on these disclosed substances, and
It was confirmed that the composition of the present invention is an excellent industrial means for obtaining a highly concentrated coal/water slurry with low viscosity. In other words, the basis of the invention of the present inventors is that the additives are cheaper and only need to be added in small amounts, and based on this, unnecessary synthetic steps (esterification) are eliminated.
By omitting this and carefully examining the combination of additive constituents, it became possible to use inexpensive and low additive amounts and obtain the desired low-viscosity, high-concentration coal/water slurry composition. . The process that led to the development of the additive useful in the present invention was that polyether compounds that have an adsorption surface for coal have a reduced degree of freedom, leading to agglomeration on the coal surface where it cannot be attached. Rather, the fatty acid or higher alcohol added as a second component adsorbs to the coal surface in an aqueous system, imparts an electric charge, and maintains the repulsive force between the particles, and the polyether compound rather helps hydrate these charged particles. It is assumed that the mechanism maintains the flow and dispersion of particles through the stabilizing action of the electric double layer.

Among the additives used in the present invention, Compound A is an aliphatic compound having two or more active hydrogens, such as ethylene glycol, propylene glycol, butylene glycol, butanediol, glycerin, trimethylolpropane, triethanolamine, diglycerin. , hydroxyl k ti -containing compounds such as pentaerythritol, sorbitan, and sorbitol, or amine compounds such as methylamine, ethylamine, propylamine, anthonia, ethylenediamine, hexamethylenezamine, and diethylenetriamine, and ethylene oxide and/or propylene oxide. It is a compound with multiple polyalkyl ether chains obtained by addition polymerization. The addition polymerization of ethylene oxide and propylene oxide may be carried out under normal conditions, or may be carried out by block polymerization or random polymerization, but block copolymerization is preferably adopted, and ethylene oxide It is preferable to perform addition polymerization to form a group. Compound A used in the present invention preferably has a polyoxene ethylene group content of 40 to 100% by weight, more preferably 70 to 90% by weight, and has a total molecular weight of 5,000% by weight.
~100,000, more preferably 20,000~so
, ooo.

On the other hand, Compound B, which is another additive, is a fatty acid having 8 or more carbon atoms, such as a saturated fatty acid such as caprylic acid, lauric acid, and stearic acid, an unsaturated fatty acid such as oleic acid and linoleic acid, or a coconut fatty acid. , human oil fatty acids,
Fatty acids containing substances with different numbers of carbon atoms such as bovine fatty acids and lanolin fatty acids can be mentioned, but purified products are not particularly required for this purpose, and rather fatty acids containing substances with different numbers of carbon atoms are useful. In addition, higher alcohols having 8 or more carbon atoms include octyl alcohol, 2-ethylhexyl alcohol, lauryl alcohol, stearyl alcohol, cholesterol, etc. In these cases, they can also be obtained by saponifying fats and oils in the same way as fatty acids. Unrefined higher alcohols having 8 or more carbon atoms and containing different substances are useful.

A low-viscosity, high-concentration coal/water slurry can be obtained by simultaneously adding these compounds A and B, but preferably the blending ratio is 5:5 to 9:1 by weight, and the coal/water slurry is preferably 5:5 to 9:1 by weight. It is advantageous to add a total amount of 0.1 to i,o% by weight, preferably 0.3 to 0.8% by weight.

Coal is either deashed coal or non-deashed coal.

Moreover, any type of charcoal can be used.

In addition, to produce slurry, coal can be coarsely pulverized, then water containing additives is added, and the slurry is made into a finely pulverized slurry using a wet pulverizer. Either method may be used, such as mixing with water to form a mixed slurry, but the particle size of the coal should be approximately 70% or more, preferably approximately 80% or more of the amount that passes through a 200 mekune (74 μm) sieve. desirable.

In general, the finer the coal particle size, the better the ignitability during combustion, but the slurry properties will increase in surface area, resulting in high viscosity or agglomeration unless the amount of additive is increased. However, the composition of the present invention has fewer such problems. The concentration of coal used is about 60% or more, preferably 7% in the coal/water slurry.
It is 0-75%. In other words, water is the cheapest medium to fluidize solid coal, but
On the other hand, in combustion, the latent heat of vaporization is rather a calorie loss. Furthermore, if the amount increases, it may cause the fire to go out, so it is desirable to use as little amount of water as possible.

In this regard, coal concentrations of 7 parts or more are generally desired,9 and the present invention achieves this concentration while still providing a slurry with a low viscosity. The low viscosity means that it is easy to transport and can be spray-combusted using ordinary combustion equipment.
This is advantageous in that.

In addition, it is also possible to add agents for the purpose of deaeration, rust prevention, corrosion prevention, antifreeze, and stability improvement to the coal/water slurry composition of the present invention.

〔Example〕

Next, the present invention will be further explained using examples. Note that parts and parts in the examples are based on weight unless otherwise specified.

Example 1 Pacific coal (volatile content 42.3%, ash content 14.9%, total 80
．． 19%) was pulverized in a hammer mill at a rotation speed of 230 Or, p, m, to obtain 200 mesh x 50 mesh with an average particle size of 70 μm.

Next, the additives of the present invention were added in the formulation shown in Table 1 in a total amount of 0.
．． After dissolving 7 parts in 60 parts of water, 140 parts of the above coarse coal particles were added, and after thorough mixing in Nigu, 60 parts in Gale Mill was added.
Coal with good fluidity was wet-pulverized for 2 hours at r, p, m.
200 parts of water slurry was obtained.

Comparative examples of additives include sodium ligninsulfonate, sodium naphthalenesulfonate formalin condensate,
Table 1 shows the results of preparation in the same manner as above, adding 1.4 parts of polyethylene glycol (molecular weight 17.000).

Note that the meanings of the symbols in the table are described after Table 2.

The physical property values in the table were measured using the methods described below.

200 mesh %: Dilute 3 g of the prepared coal/water slurry with water 50 times, pour it onto a sieve with a minimum of 200 mesh, and shake it for 1 hour after starting shaking. Calculate by drying and weighing the coal on the sieve (shaking time: 10 minutes).

Measuring device = Sieve shaker VSS-50 (manufactured by Tsutsui Rikagaku Kikai) Viscosity: Put the prepared coal/water slurry 1J3a/ into a cup and EL
Measure the viscosity after 3 minutes using a D-ST type rotor.

The rotation speed was 2 Or, p, m, (75 ec-'), and the measurement temperature was 30°C.

Measuring device = E-type rotational viscometer (manufactured by Tokyo Keiki) Static stability: Approximately 2001 d of the prepared coal/water slurry was placed in a graduated cylinder and left to stand, and the state after one week was observed by penetrating a rod. .

Below is the margin Example 2 South African coal (volatile content 33.3%, ash content 9.6t, total S
0.6%) was ground in a fine grinding type hammer mill to obtain a product with a 200 mesh pass of 78%.

Next, the additives of the present invention were added in the formulation shown in Table 2 in a total amount of 0.
After dissolving 7 parts in 60 parts of water, 140 parts of the above fine coal powder was added, and the mixture was mixed with an autohomogen mixer (manufactured by Tokushu Kika) at 4000 m
Mix at r, p, m for 5 minutes to obtain coal with good fluidity/
Water sla! J-200 parts were obtained. Physical property values were measured by the method shown in Example 1. Similarly, the total amount of additives is 0.75
A slurry with good fluidity was also obtained when 150 parts of the above fine coal powder was added after dissolving 1.05 parts of the coal powder in 50 parts of water.

As comparative examples of additives, 1 of each of the additives listed in Table 1 was used.
．． The results obtained by adding 4 parts are shown. As a reference example, examples in which the blending ratio of Compound A and Compound B deviates from the range of the claims are also described.

PG: Propylene glycol PE: Intererythritol S: Sorbitol EDA: Ethylene diamide DETA Nidiethylene triamine PO: Propylene oxide EO: Ethylene oxide Note that the numbers appended to PO and EO indicate the number of moles added to each.

Claims (1)

[Claims] 1. A highly concentrated coal/water slurry composition characterized in that at least 60% by weight of coal is finely suspended at low viscosity in an aqueous medium in the presence of the following compounds A and B: thing. Compound A: A compound having multiple polyalkyl ether chains obtained by polyalkyl etherification of an aliphatic compound having two or more active hydrogens. Compound B: Fatty acid or higher alcohol having 8 or more carbon atoms. 2. Compound A has 40 polyoxyethylene groups in its molecule.
~100% by weight, preferably 70-90% by weight,
The composition according to claim 1, having a molecular weight of 5,000 to 100,000. 3. The ratio (weight) of compound A and compound B is 5:5 to 9:
1 and containing these compounds A and B in a total amount of 0.1 to 1.0% by weight based on the coal. 4. The particle size of the coal constituting the composition is 200 mesh (
74 μm) pass approximately 70% or more
The composition according to item 1, 2 or 3.