JPH0216958B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a solid fuel-water slurry composition in which solid fuel powder such as coal, carbonized coal coke, petroleum coke, etc. is stably dispersed in water at a high concentration. Because solid fuels such as coal have a solid shape, they have long been dethroned by petroleum as the fuel of choice. ), there are many attempts to treat solid fuel as a fluid by mixing solid fuel powder 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, water has been used as a medium to disperse solid fuel at high concentrations to create a fluid slurry that is suitable for transportation by pipeline or oil tanker, and has also been used as an alternative fuel for oil in various boilers and for gasification. Attempts are being made to use it as a raw material. In the case of this slurry, since the medium is water, it is preferable that the slurry has the following properties. That is, the solid fuel powder must have a high concentration and low viscosity, and have excellent long-term stability without causing agglomeration or sedimentation of the solid fuel powder. It is also desired that the slurry be able to maintain stability even when mechanical shearing force is applied. By the way, conventionally, in order to modify the properties of coal-water slurry, rust preventives, antioxidants, etc. have been added to the slurry.
It is already known to add various additives such as dispersants. However, among these known additives, very few have been found that give very good results on solids concentration or viscosity and also satisfy both this property and the stability of the slurry. for example,
Phosphate esters, various amines, alkylene oxides, alkylphenols, naphthols, and other acidic phosphates disclosed in U.S. Patent No. 2346151, Japanese Patent Publication No. 55-45600, and Japanese Patent Application Laid-open No. 54-16511, etc. reactants, additives such as salts of polycarboxylic acids such as polymethacrylic acid,
It is difficult to obtain highly concentrated slurry due to poor viscosity reduction function. Furthermore, 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 it also has some effect on the stability of the slurry. However, 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 it is not satisfactory for practical use. I couldn't say it was possible. This invention provides an industrially useful solid fuel that has an improved low viscosity compared to those using the additives proposed above, and also has excellent slurry static stability and shear force stability. The purpose is to provide a water slurry composition, which consists of solid fuel powder, water, and additives, with a blending ratio of solid fuel powder of 50 to 80% by weight, and additives as essential components. , a) (—CH ₂ —CHX)—(X is selected from CN group and COOCH ₃ group) and b) [—
The repeating unit is CH ₂ -CH(COOM')]- (M' is a cation selected from ammonium, alkanol ammonium and alkali metal), and the average number of these repeating units per molecule is 4 to 250.
Of this number, the number of the above b units is 40~
A solid fuel-water slurry composition characterized in that it contains an oligomer containing 100% and one SO ₃ M group (M is a water-soluble cation selected from Na, K and ammonium) at the end of the molecule. It's in things. That is, the solid fuel-water slurry composition of the present invention has a solid fuel powder of 50 to 80
This composition has a low viscosity despite its high weight percent concentration, and the above essential components also contribute to improving the static stability and shear force stability of the slurry. It has excellent static stability with suppressed agglomeration and sedimentation, and also has excellent stability against shearing force without becoming compacted even when subjected to mechanical shearing force. If a composition with such excellent shear force stability is manufactured overseas, transported by long-distance pipeline or long-term ship, and then consumed in Japan, This is very advantageous because the composition can maintain sufficient stability against mechanical shearing forces. As described above, the solid fuel-water slurry composition of the present invention has advantages such as being easy and economical to transport by pipeline or other methods, and being easy to supply to a combustion device. Examples of the solid fuel powder in the solid fuel-water slurry composition of the present invention include powders of coal, carbonized coal coke, petroleum coke, and the like. Further, the type of coal may be sub-bituminous coal, bituminous coal, anthracite coal, etc., and is not particularly limited. These powders are obtained by a dry pulverization method or a wet pulverization method, and the particle size of this powder is not particularly specified. However, in order to avoid problems such as wear and blockage during pipeline transportation and burner combustion, it is usually preferable that the 200 mesh pass is 50% by weight or more.
More preferably, the content is 70% by weight or more. The blending ratio of the solid fuel powder in the slurry composition of this invention is 50 to 80% by weight, preferably
The content should be 60-75% by weight. If the blending ratio exceeds 80% by weight, the viscosity of the slurry composition will increase, which is undesirable, and if it is less than 50% by weight, the industrial usefulness will decrease, which is not preferred. The additive in the solid fuel-water slurry composition of the present invention contains the above oligomer as an essential component.
This oligomer is typically prepared by homopolymerizing acrylic acid or copolymerizing acrylic acid with acrylonitrile or methyl acrylate in water in the presence of bisulfite and optionally using a water-soluble oxidizing agent such as ammonium persulfate. After polymerization, it is obtained by neutralizing with alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine, ammonia, sodium hydroxide, potassium hydroxide, etc. As the above-mentioned bisulfite, water-soluble salts such as sodium, potassium and ammonium salts of bisulfite are used. By adjusting the usage ratio of this bisulfite to the above polymerizable monomer, the average degree of polymerization of the obtained oligomer, that is, 1
The average number of repeating units with molecules is determined. The average number of repeating units per molecule is 4.
-250, preferably 10-200. In addition, by adjusting the ratio of acrylic acid and acrylonitrile or methyl acrylate, the a unit in the resulting oligomer, that is, (-CH ₂ -CHX) - (X is a CN group and COOCH ₃
) and b units, i.e. [--CH ₂ ---CH
(COOM')] - (M' is ammonium, monoethanol ammonium, diethanol ammonium,
The ratio of cations selected from alkanol ammonium such as triethanolammonium and alkali metals such as Na and K in the molecule is determined. As for this ratio, the ratio of the number of b units to the number of repeating units in the molecule is 1
Average 40-100% per molecule, preferably 50-100%
It is better to do so. If the average number of repeating units per molecule of the obtained oligomer is less than 4 or exceeds 250, or the ratio of the average number of b units per molecule is less than 40%, the target A solid fuel-water slurry composition with such properties cannot be obtained, which is not preferable. The oligomer obtained as described above has a unit and b unit in the molecule in a specific ratio as described above, and one SO ₃ M group (M is Na, K, etc.) at the end of the molecule.
and ammonium). The additive used in this invention has the above oligomer as an essential component, and, if necessary, various additives conventionally known as additives for solid fuel-water slurries, such as gelling agents, rust preventives, antioxidants, and dispersants. It can contain agents etc. The blending ratio of the above additives in a solid fuel-water slurry composition varies depending on the characteristics of the slurry, that is, the particle size and concentration of the solid fuel powder, and the type of the active ingredient itself. , 0.01 to 5% by weight in the composition, particularly preferably
The content is preferably 0.05 to 1.0% by weight. As the amount added increases, the viscosity lowering effect becomes greater, and good 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 method of adding the additive is arbitrary, and an appropriate method may be selected depending on whether the solid fuel powder is obtained by dry pulverization or wet pulverization. For example, in the dry pulverization method, it is preferable to add and mix additives 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 or after wet pulverization. If it is difficult to obtain a stable slurry composition simply by adding additives and performing wet grinding or normal impeller stirring, mix using a stirrer with strong shearing force such as a homogenizer or line mixer. It is better. The solid fuel-water slurry composition of the present invention obtained as described above has solid fuel powder stably dispersed in water at a high concentration of 50 to 80% by weight, has a low viscosity, and can be dispersed for a long period of time. It is extremely useful industrially because it is stable over time and maintains the stability of the slurry even when mechanical shearing force is applied. Examples of the present invention will be described below to explain it more specifically. The industrial analysis values of petroleum coke obtained from bituminous coal produced in the United States and heavy oil produced in the Middle East, which were used as solid fuels in the following Examples and Comparative Examples, are shown in Table 1 below.

[Table] The oligomers used as additives in the following examples are shown in Table 2 below. The method for producing these oligomers will be described below using additive No. 3 as an example. 280 g of water, 16.4 g (0.088 mol) of sodium bisulfite, 110 ml (0.904 mol) of acrylic acid, and 57 ml (0.485 mol) of acrylonitrile were placed in flask 1, and the temperature was adjusted to 30° C. with stirring under a nitrogen atmosphere. Then add 1 ml of a 10% aqueous solution of ammonium persulfate.
was dripped little by little from the burette at a dropping rate of 0.25 ml/hour. The resulting solution was neutralized with 115 g of a 50% by weight aqueous sodium hydroxide solution to a pH of 11.5.
An oligomer solution with a solid content concentration of 39.2% by weight was obtained. The solid content in this solution was used as an additive.

【represent.
(*2) Contains less than one SO ₃ M group per molecule.
In addition, the additives used in the following comparative examples were sodium naphthalene sulfonate formalin condensate (additive No. 7) with an average degree of condensation of 6 and an average molecular weight of 2000.
sodium polyacrylate (Additive No. 8). As for the properties of the solid fuel-water slurry compositions obtained in the following Examples and Comparative Examples, viscosity, static stability, and stability against shearing force were measured as follows. The viscosity (25° C.) of the composition was measured using a B-type viscometer, and the static stability was examined using the following method. That is,
A stainless steel cylinder with a diameter of 5 cm and a height of 20 cm was provided with outlet ports with stoppers at positions 6 cm and 12 cm from the bottom, and the obtained composition was poured into the cylinder to a depth of 18 cm from the bottom and allowed to stand at room temperature for 4 weeks. did. Next, the cylinder is divided into an upper layer above 12 cm from the bottom, a middle layer between 6 to 12 cm, and a lower layer below 6 cm, and the solid content of each layer is measured by the loss on drying method, which is left in a dryer at 105°C for 1 hour. did. Further, stability due to shear force was determined by the following method. That is, the diameter of the resulting composition
800ml in a baker with a size of 10.5cm and a height of 15cm
Fill the impeller with a blade diameter of 2cm to 400ml.
and stirred at 200 rpm for 24 hours.
After the stirring was stopped, the impeller was removed and left as it was for 14 days. Next, tilt the beaker to pour out the composition, and if it all flows out, it will remain at the bottom, but if it can be easily re-fluidized with a glass rod, etc.
Cases in which hard sediment is formed at the bottom and cannot be easily removed with a spatula are represented by ◎, 〇, and ×, respectively. In the case of ◎ and 〇, a composition that is strong against shearing force is obtained. It was determined that Examples 1 to 6 and Comparative Examples 1 to 2 American bituminous coal was dry-pulverized to obtain coal powder containing 70% by weight of 200 mesh passes. The moisture content of this powder was 2% by weight (including adhering water). Next, 1.5 g of the additives shown in Table 3 below were added to each beaker in Examples 1 to 6, and 1.5 g in Comparative Examples 1 to 2.
Now, take 142.9 g of an aqueous solution in which 2.0 g has been dissolved, and use a Homomixer M type manufactured by Tokushu Kika Kogyo Co., Ltd. to mix 300 ~
Add the above coal powder while stirring slowly at 500 rpm.
357.1 g was gradually added, and after the addition was completed, the rotation speed of the homomixer was increased to 5000 rpm and stirred for 10 minutes to obtain a coal-water slurry composition with a solid content of 70% by weight. The properties of the obtained slurry composition were investigated using the above method, and the results are shown in Table 3 below.

[Table] Examples 7 to 12 and Comparative Examples 3 to 4 360 g of petroleum coke coarsely ground to a particle size of 2 mm in a ball mill with a capacity of 5 (ball filling rate 30% by volume)
To this, add 140 g of an aqueous solution containing 1.75 g of each of the additives shown in Table 4 below, and grind for 30 minutes to reduce the particle size of petroleum coke powder.
A petroleum coke-water slurry composition with a solids content of 72% by weight and a 200 mesh pass of 78% by weight was obtained. The properties of the obtained slurry composition were examined by the above method, and the results are shown in Table 4 below.

【table】

[Table] As is clear from the above test results, the solid fuel-water slurry composition of the present invention has a high concentration and low viscosity, and is homogeneous with excellent static stability and stability against shear force. It is something.

Claims (1)

[Claims] 1 Consisting of solid fuel powder, water and additives, the blending ratio of solid fuel powder is 50 to 80% by weight, and the additive is an essential component, a) (-CH ₂ - CHX) - ( X is
CN group and ₃ COOCH groups) and b) [-CH ₂ -CH(COOM')]- (M' is a cation selected from ammonium, alkanol ammonium and alkali metal) as repeating units; The average number of repeating units per molecule is 4 to 250, and of this number, the number of b units described above accounts for 40 to 100%, and one at the end of the molecule.
A solid fuel-water slurry composition comprising an oligomer having SO ₃ M groups, where M is a water-soluble cation selected from Na, K and ammonium. 2 Claim 1 in which the solid fuel powder is powder of coal, carbonized coal coke, or petroleum coke
The solid fuel-water slurry composition described in Section 1.