JPH0132877B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for improving the fluidity of a coal/water slurry, and more specifically, the present invention relates to a method for improving the fluidity of a coal/water slurry, and more specifically, by adding a certain fluidity improver when preparing a water slurry of coal powder, it is possible to improve pipeline transportability. This relates to a method of making coal/water slurry. In recent years, as the oil supply situation has worsened, coal, which is rich in resources and has wide reserves and is distributed all over the world, has been reconsidered as an alternative energy source to oil. However, coal is a bulk material and has various problems in handling. In particular, unlike petroleum, which is a liquid, transporting it requires enormous capital investment, power, and labor, and in the case of coal powder, it is also necessary to take measures to prevent deterioration of the working environment due to dust generation and spontaneous combustion. Liquefaction and gasification of coal have been considered for a long time as a solution to these problems, but it is said that it will still take a considerable amount of time to put them into practical use. As a link or a method of supplying raw materials during liquefaction or gasification, fluidization by dispersing coal powder in a liquid such as water, petroleum, or methanol is considered. Among these methods, the method of dispersing coal powder in water to form a slurry has various advantages because the medium is water, and has already been put into practical use for long-distance overland pipeline transportation of coal from the base of a mountain. However, increasing the coal concentration in the slurry significantly deteriorates the fluidity of the slurry, so currently it is carried out at a coal concentration of 45 to 60% by weight. Therefore, at present, there are problems in terms of transportation efficiency, dewatering efficiency, wastewater treatment cost, combustion efficiency in the case of direct combustion in a boiler, etc., and it has not become widely used. Conventionally, various methods have been proposed in order to increase the coal concentration in this coal powder/water slurry, such as adjusting the particle size of the coal powder and reducing the viscosity of the slurry by adding a dispersant. For example, JP-A-53-581 discloses a method for obtaining a highly concentrated coal/water slurry by adding organic sulfonate or lignin sulfonate together with ammonium hydroxide; Although the slurry viscosity decreases considerably,
The reality is that it has not yet been adopted industrially because it is not yet satisfactory. In addition, highly concentrated coal/water slurry exhibits non-Newtonian fluidity and is a pseudoplastic or non-Bingham plastic fluid, so depending on the type of coal, it will not flow at all or will flow only very slightly in response to relatively small stress. . Therefore, it is desirable that the dispersant and fluidity improver not only reduce the apparent viscosity in a steady state under fairly high stress, but also reduce the apparent yield value. However, the so-called lignin sulfonate has a small effect of reducing this apparent yield value;
Furthermore, depending on the type of coal, there are cases where it exhibits dilatancy under high stress. On the other hand, naphthalene sulfonic acid formalin condensate derivatives, which are also known as dispersants (for example,
56-21636) also does not have a sufficient viscosity reducing effect, and depending on the type of coal, the apparent yield value is often high. Furthermore, a formalin cocondensate of naphthalenesulfonic acid and ligninsulfonic acid has a similar tendency and is insufficiently effective. The inventors of the present invention have conducted extensive research on methods for further reducing the apparent viscosity and apparent yield value in a steady state of highly concentrated coal/water slurry and improving its fluidity. As at least a part of the fluidity improver, sulfite pulp cooking effluent is oxidized with any one of a naphthalene sulfonic acid formalin condensate or a formalin cocondensate of naphthalene sulfonic acid and lignin sulfonic acid per phenylpropane unit. Lignosulfonic acid derivatives partially desulfonated to a degree of sulfonation of 0.35 mol or less (e.g.,
21636) at a solid content weight ratio of 2:8 to 8:2, the fluidity of the slurry was improved to an extent that could not be predicted from the results obtained when each was used alone. The present invention has been achieved based on the discovery that this can be significantly improved. In the present invention, the naphthalene sulfonic acid formalin condensate refers to a naphthalene sulfonic acid formalin condensate produced by a known method. Further, the co-condensate of naphthalene sulfonic acid, a lignin sulfonic acid derivative, and formaldehyde refers to one obtained, for example, by the method of Patent No. 1019746.
In addition, partially desulfonated ligninsulfonic acid derivatives are obtained by oxidizing sulfite pulp waste liquid or lignosulfonic acid (salt) obtained by fractionating it at a high temperature as is known, so that the degree of sulfonation becomes 0.35 mol or less per phenylpropane unit. There are no products that have been partially desulfonated to the point where they have been partially desulfonated, and products that have been subjected to a secondary chemical treatment.Compared to untreated products, there are more carboxyl groups and phenolic hydroxyl groups after partial desulfonation, and there are no sulfonic groups or alcohols. There are few hydroxyl groups. The most common method for partial desulfonation is to initially treat the product at 150 to 200°C at a pH of 9 or higher, but it is not limited to this method. Partial desulfonation may also be used. That is, this partially desulfonated lignin sulfonic acid derivative is obtained by oxidizing sulfite pulp cooking effluent as described above, and has a limited degree of sulfonation. Further, when the sulfite pulp waste liquid is subjected to a partial desulfonation treatment, the reaction product may be used as is, or only high molecular weight fractions may be separated from the reaction product and used. The ratio of the partially desulfonated ligninsulfonic acid derivative to either one of the naphthalenesulfonic acid formalin condensate or the formalin cocondensate of naphthalenesulfonic acid and ligninsulfonic acid is 2:8 to 8:1 in terms of solid content weight. The ratio should be 2. Outside this range, the synergistic effect of both is small and close to the effect when each is used alone. The total amount of both added is 100% coal powder bone dry weight.
A range of 0.2 to 2 parts by weight is desirable.
If it is less than 0.2 part by weight, the fluidity improvement effect is small;
Moreover, if the amount is more than 2 parts by weight, little additional effect can be expected, or on the contrary, the effect will be worse. The addition may be made at any time, such as when preparing the coal powder/water slurry or when pulverizing the coal. Although the method of the present invention is effective regardless of the coal concentration in the slurry, it is particularly significant in high-concentration slurries with a coal concentration of 60% by weight or more.
In addition, in the method of the present invention, it is possible to further use known additives such as polyoxyalkylene alkyl phenyl ether, carboxymethyl cellulose, polyacrylate, and condensed phosphate as a fluidity improver. Although the detailed mechanism of dispersibility improvement by the method of the present invention is unknown, firstly, the addition of partially desulfonated lignin sulfonate results in a decrease in sulfonic groups and alcoholic hydroxyl groups compared to a salt that is not partially desulfonated. Formation of favorable charge balance with hydrophobic coal powder particles derived from increased phenolic hydroxyl and carboxyl groups;
Furthermore, it is believed that this was achieved by exhibiting a synergistic effect between this partially desulfonated product and the naphthalene sulfonic acid formalin condensate. This is also believed to be due to the fact that this method has excellent surface activity. The present invention will be further explained below with reference to Examples.
The present invention is not limited to these examples. Example 1 Trade name: Vanillex N (product of Sanyo Kokusaku Pulp Co., Ltd., partially desulfonated sodium lignin sulfonate, degree of sulfonation per phenylpropane unit)
0.13 mol) by a conventional method (referred to as SM-1; degree of sulfonation per phenylpropane unit: 0.43 mol) and a β-naphthalenesulfonic acid formalin condensate produced by a known method (average Condensation degree 8) sodium salt (NSF-
1) was mixed at a solid content ratio of 8:2, 5:5, and 2:8 in 169 g of each aqueous solution in which an amount equivalent to 0.6% by weight based on absolute dry weight of coal was dissolved in solid content.
331g of Miike charcoal finely ground to 80% pass
(moisture 1.9%) and T.
A coal/water slurry with a coal concentration of 65% by weight was prepared by stirring at 8000 rpm for 40 minutes using a K. homomixer. The apparent viscosity of each slurry in a steady state and the apparent yield value obtained by extrapolating the straight line portion of the stress-shear rate curve were measured using a rheometer, and the results shown in Table 1 were obtained. The liquid temperature of the slurry at the time of measurement was 20
It is ℃. For comparison, measurements were also conducted on systems using SM-1 and NSF-1 alone, and systems using samples in which both were mixed at a solid content weight ratio of 9:1 and 1:9. In the table, the lower the apparent viscosity and yield value of the slurry, the better the fluidity.
It was found that it had significantly superior fluidity compared to No. 4.

[Table] Example 2 A solution in which 45% by weight of NaOH was added to the solid content of Na-based sulfite pulp wastewater with a concentration of 40% by weight.
After an alkaline air oxidation treatment at 170-180°C for 60 minutes, H ₂ SO ₄ was added to adjust the pH to 3, and the partially desulfonated ligninsulfonic acid was fractionally precipitated. This precipitate was neutralized to pH 8 with NaOH to obtain partially desulfonated sodium lignin sulfonate (DSL-1) with a purity of 90% and a degree of sulfonation of 0.15 mol. This DSL-1, the sodium salt of β-naphthalenesulfonic acid formalin condensate (average degree of condensation 4) (NSF-2) produced by a known method, and a sample in which both were mixed at a solid content ratio of 5:5 were prepared. Each added 0.6% by weight of absolute dry coal based on solid content,
The coal concentration was 65% by weight and 67% by the method according to Example 1.
A slurry of % by weight was prepared. After adjusting the temperature of each slurry to 20° C., the slurry was subjected to measurement of its apparent viscosity and apparent yield value in the same manner as in Example 1. The results are shown in Table 2, and the slurry of Example 4 of the present invention showed good fluidity not only when the coal concentration was 65% by weight but also at 67% by weight.

[Table] Example 3 Using DSL-1 and NSF-2 of Example 2 and a fluidity improver in which both were mixed at a ratio of 5:5,
The influence of the amount of each fluidity improver added was investigated at a slurry coal concentration of 65% by weight, and the results are shown in Table 3.

【table】

[Table] Example 4 Product name, Sun Extract C (product of Sanyo Kokusaku Pulp Co., Ltd.)
Add 1/2 of the calcium content and equimolar amount of H ₂ SO ₄ to the main component (calcium lignin sulfonate), and remove 1/2 of the calcium content as gypsum by fractionation. The resulting liquid is heated to a hot air inlet temperature of 20°C. The powder was sprayed into a spray dryer to perform an instantaneous gas-phase desulfonation reaction, and the resulting powder was dissolved in water.
The mixture was neutralized to pH 6 with Ca(OH) ₂ and insoluble matter was removed to obtain a reaction product (DSL-2) whose main component was partially desulfonated calcium lignin sulfonate with a degree of sulfonation of 0.29 mol. Sunextract C before treatment
The degree of sulfonation of calcium lignin sulfonate was 0.50 mol. This DSL-2, the product name Sunflow PS (product of Sanyo Kokusaku Pulp Co., Ltd., naphthalene sulfonic acid/modified lignin sulfonic acid/formalin cocondensate), and a sample in which both were mixed at a ratio of 5:5, and Samples containing polyoxyethylene nonyl phenyl ether (15 moles of ethylene oxide added) with a solid content of 1% were added in an amount of 0.8% by weight based on the absolute dry weight of the coal in terms of solid content, and the same method as in Example 1 was carried out. A slurry with a coal concentration of 65% by weight was prepared. After adjusting the temperature of each slurry to 20° C., the slurry was subjected to measurement of its apparent viscosity and apparent yield value in the same manner as in Example 1. The results are shown in Table 4.

【table】

[Table] Example 5 A 30% aqueous solution of DSL-1 described in Example 2
A methylolated product of partially desulfonated sodium ligninsulfonate obtained by adding 2% by weight of HCHO based on the solid content and reacting at 120°C for 30 minutes and NSF-
A slurry with a coal concentration of 65% by weight was prepared in the same manner as in Example 1 by adding 0.6% by weight of the absolute dry weight of coal in terms of solid content, and adding a fluidity improver in which 2 was mixed at a solid content ratio of 5:5. The apparent viscosity and apparent yield value were 400 cp and 110 dyne/cm ² , respectively, lower than the values of 910 cp and 540 dyne/cm ² when the methylol compound was used alone, and the fluidity was good. As shown in the above examples, the addition of the product of the present invention was compared with a conventional waste liquid product without desulfonation, a naphthalene sulfonic acid formalin condensate alone, and a mixture of the two in a ratio of 9:1 to 1:9. The apparent viscosity of the slurry decreased significantly in all cases (1 to 4).
Table), the present invention was completed with improved fluidity.

Claims (1)

[Scope of Claims] 1. When preparing a coal powder/water slurry, at least a part of the fluidity improver is a naphthalene sulfonic acid formalin condensate or a formalin cocondensate of naphthalene sulfonic acid and lignin sulfonic acid. Sulfonation degree per phenylpropane unit by oxidizing seeds and sulfite pulp cooking effluent
A method for improving the fluidity of a coal/water slurry, characterized in that a lignosulfonic acid derivative partially desulfonated to 0.35 mol or less is used in a ratio of 2:8 to 8:2 in terms of solid content weight. 2 The total amount of either one of the naphthalene sulfonic acid formalin condensate or the formalin cocondensate of naphthalene sulfonic acid and lignin sulfonic acid and the partially desulfonated lignin sulfonic acid derivative is 0.2 parts by weight per 100 parts by weight of bone dry coal powder. The coal according to claim 1 in the range of ~2 parts by weight.
A method for improving the flowability of water slurries. 3. The method for improving the fluidity of a coal/water slurry according to claim 1 or 2, wherein the coal concentration of the coal/water slurry is 60% by weight or more.