JPS62232493A - High-concentration coal/water slurry composition - Google Patents

Abstract

PURPOSE:To obtain a high-concn. coal/water is slurry compsn. having an increased coal concn., having a low viscosity and an excellent flowability and permitting ready transportation and combustion as in the case of heavy fuel oil, by suspending fine grains of coal in an aq. medium in the presence of a particular compd. CONSTITUTION:Polybutadiene glycol having an MW of 1,000-4,000 is addition- polymerized with ethylene oxide and a 3C or higher alkylene oxide (e.g., propylene oxide), optionally followed by neutralization by means of sulfuric or phosphoric esterification, thereby obtaining either a polyalkyl ether compd. (A) of 5,000-100,000 in MW having a polyoxyethylene group content of 40-100wt%, pref. 70-100wt% based on the whole amt. of the alkylene oxide incorporated in the molecule and always having a polyoxyethylene group at its terminal, or a sulfuric or phosphoric ester salt thereof (B). Then, fine grains of coal having such a grain size that at least about 70wt% grains pass through a 200-mesh (74mum) sieve are suspended in an aq. medium contg. 0.1-1.0wt%, based on the coal, of compd. A and/or compd. B.

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]

In recent years, the development of the use of coal as an energy alternative to petroleum has become a global trend, as oil as an energy source is uncertain about its long-term supply stability and is considered to be more economical than petroleum, even when handling costs are included. is being promoted. The main problems in handling coal are that it is solid, making it difficult to transport by pipeline or storing in tanks, and that it has a high ash content. ), coal/water slurry (CWM or cws), coal/
Slurry compositions such as methanol slurry (Methacoal) are being considered. As a medium for these slurry compositions, it is practical to use water, which is inexpensive and easy to supply, and is the focus of research.

Although coal has hydrophilic groups such as hydroxyl groups and carboxylic acid groups in its molecules, it is hydrophobic as a whole.
When a large amount of fine coal powder is mixed with water, it does not wet well with water and is not evenly distributed, resulting in a slurry with extremely poor fluidity. All you get is a slurry. coal/
In order for water slurry to work effectively as a fuel, a coal concentration of at least 70% is generally required, taking into consideration the latent heat of vaporization of water. In order to achieve this, we need to ensure that the coal particles are properly distributed and that a surfactant is added between the coal and water that can maintain the dispersion of the coal and improve its fluidity. Agents are being considered.

Conventionally, lignin sulfonate (Japanese Unexamined Patent Application Publication No. 1989-1999
7-96090, etc.), polycyclic aromatic sulfonate formalin condensates (Japanese Patent Publication No. 57-145193, etc.), or polyether compounds similar to the compounds used in the present invention (Japanese Patent Application Publication No. 57-147595, etc.). be. Each of these additives has its own characteristics, but they have problems such as requiring a relatively large amount to be added in order to make a slurry with a coal concentration of 70%, and their fluidity being insufficient. .

[Problem that the invention seeks to solve]

When creating a highly concentrated coal/water slurry using additives, the cost of the additives increases the total cost of the slurry.
There is no point in eliminating the cost advantage as a petroleum substitute, so it is required that the additive be inexpensive or that it can provide the desired slurry by adding a small amount.

The object of the present invention is to provide a coal/water slurry composition that meets this requirement and is transportable and combustible on a par with heavy oil.

[Means for solving problems]

According to the present invention, high concentration coal/
A water slurry composition is provided.

Compound A: A polyalkyl ether compound obtained by addition polymerizing polybutadiene glycol with ethylene oxide and alkylene oxide having 3 or more carbon atoms.

Compound B: Compound A sulfur ester salt or phosphate ester salt.

In the present invention, preferably, the compound A and/or B is added to the aqueous medium as an additive to the coal.
．． A coal/water slurry composition is provided in which 1 to 10% by weight of coal is present, and 60% by weight or more of the total amount of coal is suspended in a low viscosity with a particle size of about 70% or more in a 200 mesh (74 μm) pass.

The compound used as an additive in the present invention contains 40 to 100% by weight of polyoxyethylene groups, preferably 70 to 100% by weight, based on the total added alkylene oxide.
A polyalkyl ether compound of polybutadiene glycol (compound A) containing % by weight and always having a polyoxine ethylene group at the end, and its sulfuric acid ester salt or phosphoric acid ester salt (compound B), molecular weight is 5,
000 to 10'0.000.

The performance of additives is greatly influenced by their ionicity, the type of hydrophilic group, the type of hydrophobic group, the bond structure between hydrophilic and hydrophobic groups, the ratio of amounts of hydrophilic and hydrophobic groups, and the molecular weight.
Compounds useful in the present invention are those that achieve the desired performance, particularly by controlling the type of hydrophobic group, the ratio of amounts of hydrophilic groups to hydrophobic groups, and the balance of molecular weight.

Compound A was synthesized by adding ethylene oxide, nolopyrene oxide, butylene oxide,
Addition polymerization of styrene oxide, etc. The addition polymerization may be performed by block polymerization or random polymerization of these alkylene oxides, but block copolymerization is preferably employed. Ethylene oxide forms a hydrophilic group in alkylene oxide, and it is preferable to add-polymerize part or all of it to form a terminal group. Since polybutadiene glycol is a hydrophobic group, compound A may be formed by addition polymerization of only ethylene oxide. During these polymerizations, it is clear that if polyethylene glycol or the like is produced as a by-product due to the presence of a trace amount of water, sufficient performance cannot be achieved. It is obtained by sulfuric acid esterification or phosphoric acid esterification under normal conditions, and then neutralization with an organic or inorganic alkali.

The coal may be deashed coal or non-deashed coal, and any type of coal can be used. In addition, after coarsely pulverizing the coal, water containing additives is added to form a finely pulverized slurry in a wet pulverizer, or the coal is first pulverized in a dry pulverizer and then mixed with water containing additives. F
Any method of setting IJ- may be used. The coal particle size in the slurry is desirably about 70 inches or more, preferably about 80 inches or more, as the amount passing through a 200 mesh (74 μm) sieve. In general, the finer the coal particle size, the better the ignitability during combustion, but the slurry properties (due to an increase in surface area) may become highly viscous or viscous if the amount of additive is not increased. There are also negative aspects such as agglomeration. However, such problems are rare in the composition of the present invention. The concentration of coal used is about 60% or more in the coal/water slurry, preferably 70-75%. Water is the cheapest fluidizing medium, but it absorbs latent heat of vaporization during combustion, resulting in calorie loss. Furthermore, if the amount increases, it may cause the fire to go out, so it is desirable to reduce the amount of water as much as possible. From this point of view, a coal concentration of 70% or more is generally desired, and the present invention achieves this concentration while still providing a slurry of low viscosity. Low viscosity means
This is extremely advantageous as it means that spray combustion can be carried out in a normal combustion device rather than in a bulky container that is easy to transport.

Note that the coal/water slurry composition of the present invention includes deaeration,
It is also possible to add chemicals for the purpose of rust prevention, antiseptic, antifreeze, and stability improvement.

〔Example〕

Next, the present invention will be further explained by examples. In addition, unless otherwise specified, parts and parts in the examples are based on weight.

Example 1 Pacific coal (volatile content 42.3%, ash content 14.9%, total 80
．． 19%) in a hammer mill for 2,300 r, p, m
.

The powder was crushed at a rotational speed of 200 mesh passes 50% and 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 a kneader, the mixture was heated to 6 O in a ball mill.
Coal with good fluidity was wet-pulverized for 2 hours at r, p, m.
200 parts of water slurry IJ was obtained.

Comparative examples of additives include sodium lignin sulfonate, sodium naphthalinosulfonate formalin condensate,
or polyethylene glycol (molecular weight 20,000)
The results are shown in Table 1.

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

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

Coal/water slurry made with 200 mesh pasties! J-3,9 was diluted 50 times with water and poured onto a sieve of at least 200 mesh.
After starting shaking, wash with 1 liter of water, dry and weigh the coal on the sieve, and calculate (shaking time 10 minutes).

Measuring device: Sieve shaker VSS-50 (manufactured by Tsutsui Rikagaku Kikai) Put the prepared coal/water slurry 3- into a cup and EL
The viscosity was measured after 3 minutes using a D-8T type rotor. Rotation speed: 2 Or, p, m, (7 sec""'), measurement temperature: 30°C.

Measuring device: E-o rotational viscometer (manufactured by Tokyo Keiki) Static stability Approximately 200 mm of the prepared coal/water slurry was placed in a graduated cylinder and allowed to stand, and the state after one week was observed by penetrating the cylinder with a rod.

Below is the margin Example 2 South African coal (volatile content 33.3%, ash content 9.6%, total 5
066%) was pulverized with a fine grinding machine hammer mill, and 200%
I got a mesh pass of 78 inches.

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, add 140 parts of the above fine coal powder, and mix with an autohomogen mixer (manufactured by Tokushu Kika) to 4.00 parts.
Mixing was carried out for 5 minutes using Or, p, m, to obtain 200 parts of coal/water slurry with good fluidity.

Physical property values were measured by the method shown in Example 1.

Similarly, slurries with good fluidity were also obtained when 0.75 parts or 1.05 parts of the total amount of additives were dissolved in 50 parts of water and then 150 parts of the above fine coal powder was added.

As a comparative example of additives, the results were shown by adding 4 parts of each of the additives shown in Table 1.

Margin below In addition, each symbol in Table 1 and Table 2 means the following.

PBG: Polybutadiene glycol RO: alkylene oxide PO: f Robylene oxide EO: Ethylene oxide

Claims (1)

[Claims] 1. Highly concentrated coal/, characterized in that at least 60% by weight of coal is finely suspended with low viscosity in an aqueous medium in the presence of the following compounds A and/or B: Water slurry composition. Compound A: A polyalkyl ether compound obtained by addition polymerizing ethylene oxide and alkylene oxide having 3 or more carbon atoms to polybutadiene glycol. Compound B: Compound A sulfate ester salt or phosphate ester salt. 2. Compound A or B has 40 polyoxyethylene groups on the entire alkylene oxide added to the molecule.
-100% by weight, preferably 70-100% by weight,
necessarily have a polyoxyethylene group at the end, and 5,
A composition according to claim 1 having a molecular weight of 000 to 100,000. 3. 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 or 2. 4. The composition according to any one of claims 1 to 3, which contains 0.1 to 1.0% by weight of compounds A and/or B based on coal.