JPH0520480B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a dispersant for a coal/water chiller. Specifically, it relates to a reaction product of a modified lignin sulfonate, naphthalene disulfonic acid, and naphthalene sulfonic acid under acidic conditions. [Prior art] A method of using lignin sulfonate (LSA salt) or naphthalene sulfonic acid formaldehyde condensate (NSF) salt as a dispersant for a coal-water chiller (hereinafter abbreviated as CWM) is described in JP-A-52-71506;
It is already known in Japanese Patent Publication No. 60-6395. As a patent that further develops this, a condensation reaction product of naphthalene sulfonic acid (NS), lignin sulfonic acid (LSA) derivative [desulfonated lignin sulfonate (DSL)], and formaldehyde (HCHO) is used as a dispersant. A method (Japanese Patent Application Laid-Open No. 58-34896) is disclosed. In addition, in JP-A-60-26090, the ligninsulfonic acid to be co-condensed is obtained by sulfonating wood chips, and the chemical treatment process, hydrolysis reaction, oxidation reaction, desulfonation reaction, and demethylation reaction is A condensed lignin sulfonic acid with a modified lignin sulfonic acid, which has been subjected to the following methods, is disclosed. However, in this case, a general reaction treatment is merely exemplified. For example, when considering one oxidation reaction, the modified lignin sulfonic acid will vary depending on the chemical used for the oxidation reaction and the extent of the reaction. Therefore, if the chemical treatment is not appropriate, it will have a negative effect. The method disclosed in JP-A-58-34896 is obtained in accordance with the method described in JP-A-52-25433. Therefore, this method uses a cement dispersant that has been subjected to reaction treatment to be suitable for use as a cement dispersant.
It is interpreted as applied to CWM. In addition, in the field of cement dispersants,
5051, 60-5052 are disclosed. This uses an ultrafiltered LSA salt instead of DSL, which is subjected to a condensation reaction, and then subjected to an oxidation reaction. However, at first glance, cement pulverized coal is similar in that it handles the same fine particles, but the former is an inorganic substance and is a hydraulic substance, whereas the latter is an organic substance and has no hydraulic properties, and also has a different surface structure. . Particularly in the case of the former dispersant, in addition to high dispersibility, concrete setting retardation and air entrainment properties are important. When the degree of condensation is low, the amount of entrained air increases, so the degree of condensation of the reactant is important, and it is generally used as a high condensate. On the other hand, in the latter case, in addition to dispersibility, emphasis is placed on the storage stability of the resulting CWM. Therefore, it is natural that the manufacturing method of the optimal dispersant used for this will be different. [Problem to be solved by the invention] An economical and high-performance product that can withstand industrial use.
CWM dispersants are currently unknown. Here, a high-performance dispersant is one that is less affected by the type of coal and has the following advantages: (1) It has a large viscosity-reducing effect with a small amount added. (2) High storage stability. That's true. [Means for solving the problem] The present inventors have developed CWM based on NS, LSA salt, and HCHO.
As a result of detailed and intensive research into dispersants, we have found that high performance can be achieved by using a special lignin sulfonate treated with naphthalene disulfonic acid and an oxidation reaction.
Successfully developed a dispersant for CWM. That is, in the present invention, high-temperature alkaline air oxidation treatment was performed.
NS,
The main feature is that it reacts with HCHO. For more details, please refer to the sulfite pulp waste liquid (SSL)
The SO ₃ H group is left intact, i.e., it is not subjected to a vigorous oxidation reaction until the desulfonation reaction occurs (DSL
(Does not undergo violent oxidation reaction until precipitation occurs under acidic conditions), increases other functional groups such as phenolic OH and carboxyl groups, and at the same time, reducing sugars and sugar denatured products other than LSA salts do not become reaction inhibitors. A suitable oxidation reaction is carried out. Specifically, NaOH is 5 to 20% of the SSL solid content.
% addition, temperature 150-200°C, time 1-2 hours, wet oxidation while blowing air or oxygen. Naphthalenedisulfonic acid (NDS) referred to here
refers to a substance whose main component is 2,6-naphthalene disulfonic acid and which also contains 2,7-naphthalene disulfonic acid and the like. The thus obtained modified LSA salt (TLS′) and NDS
React with NS and HCHO using both. This method is carried out according to Special Publication No. 52-25433,
The details will be described next. The basic manufacturing method for dispersants is to add sulfuric acid and water to NS and NDS, heat this to 80-95℃, and then
Add 37% HCHO over approximately 2 hours. Add HCHO and TLS′ to this, and add 90 to 120
The product is made by reacting at ℃ for 5 to 20 hours to neutralize and remove inorganic salts. The ratio of chemicals used in the reaction is 5 to 50 parts (parts by weight, the same hereinafter), preferably 15 to 40 parts, per 100 parts of NS. If it is more than 50 copies, there will be a lot of unreacted NS, which is not preferable. Moreover, if it is less than 5%, it becomes close to NSF and the characteristics of the present invention cannot be exhibited. NDS is 5 to 20 parts per 100 parts of NS, preferably
10 to 15 parts is good. Next, the appropriate amount of HCHO to be used initially is 20 to 25 parts per 100 parts of NS. The amount of HCHO added together with TLS' is 20 to 100 parts per 100 parts of TLS'. The amount of water and sulfuric acid initially mixed with NS is 15 to 30 parts, preferably 18 to 25 parts, per 100 parts of NS.
Sulfuric acid is 20-40 parts. The reaction temperature is 90-130°C and the reaction time is 5-20 hours. In the present invention, the HCHO reactant is neutralized to form an alkali metal salt, an ammonium salt, a lower amine salt, or the like. The alkali metals include Na, Li, and K salts, and the lower amine salts include monoethanolamine, diethanolamine, and triethanolamine salts. The coal to which the dispersant used in the present invention is applied is not particularly limited, and may include lignite, subbituminous coal, bituminous coal, anthracite coal, and the like. There is no particular limitation on the particle size of the coal, but it is preferably 50% or more, preferably 70 to 80%, when passing through 200 meshes. In the present invention, it is also possible to use known additives such as CMC, MC, polyacrylates, and condensed phosphates. Other dispersants such as NSF and LSA salts can also be used in combination. [Operation] What is the difference in reaction between the TLS' and NDS combination system obtained by oxidation reaction treatment under special conditions in the present invention and the reaction system with DSL, NS, and HCHO that have been used conventionally? It's not clear. However, since DSL contains less SO ₃ H, precipitation occurs in the reaction system when the amount is increased, whereas this does not occur in the case of TLS'. Furthermore, functional groups such as phenolic OH and carboxyl groups are increased compared to ordinary LSA salts, and reducing sugars and sugar modifications are in a form that does not inhibit the reaction, resulting in higher reactivity. Conceivable. NDS used in combination has a negative effect when producing high-performance water reducer NSF high condensation using ordinary concrete admixtures, but it has a positive effect when used in combination with TLS' as in the present invention. The reason for this is unknown, but it seems to be related to its affinity with TLS'. It is assumed that as the amount of functional groups in the reactant and the ratio of LSA salt increase, the affinity with coal increases, resulting in a higher performance dispersant. [Example] <Preparation of special lignin sulfonate (TLS')> Na of sulfite pulp concentrate (SSL-Na)
The pH was adjusted to 12 with NaOH, and alkaline air oxidation was performed at a high temperature of 150 to 160°C for 2 hours. <Preparation of NS/NDS/TLS'/HCHO reactant> A mixture of 80 parts of NS, 20 parts of NDS, 35 parts of 98% H ₂ SO ₄ and 20 parts of water was heated to 80-90°C, and 23 parts of 37% HCHO was heated for 2 hours. Added over time. After that, a solution consisting of 30 parts of TLS' and 23 parts of 37% HCHO was added in 4 portions at 1 hour intervals, and the mixture was heated to 95-100°C.
The reaction was allowed to proceed with stirring for 2 hours. After the reaction is complete, cool, neutralize with NaOH, and _{remove Na2SO4.}
was removed by crystallization. (A ₁ ) DSL was reacted in the same manner. (B ₁ ) A ₂ was also reacted in the same manner at the proportions shown in Table 1. <Preparation method of coal/water chiller and flowability measurement method> (1) Preparation method of coal/water chiller Add bituminous coal pulverized to 200 mesh to 80% pass into water in which a predetermined amount of dispersant has been dissolved in advance. After adding (total amount 400g) and thoroughly moistening it with a mixing stick (making it into a paste), stir it at 8000rpm for 40 minutes using a Nippon Tokushu Kika Kogyo TK Homo mixer to prepare a coal/water slurry, and heat it at 20℃. The slurry viscosity was measured using a BL rotational viscometer. Table 1 shows examples and comparative examples conducted under these conditions.
and shown in Table 2. Low viscosity indicates good fluidity. (2) Stability measurement method for coal/water slurry The coal/water slurry prepared under the conditions in (1) was transferred to a cylinder (inner diameter 35 mm, height 250 mm), and a glass rod with a diameter of 6 mm and a weight of 30 g was penetrated into the slurry. The falling condition was measured over time. If the glass rod penetrates all the way to the bottom under its own weight, the slurry will have good stability, but it will stop at 1/2 or more of the way down.
If it does not penetrate downward even when pushed by hand, the stability becomes poor. Tables 1 and 2 show examples and comparative examples in which the stability of the slurry was measured under these conditions and the number of days it lasted. A longer duration indicates better stability.

【table】

〔Effect of the invention〕

According to the present invention, TLS′ can be used instead of conventional DSL.
By using NDS in the reaction with NS and HCHO, a high-performance dispersant for CWM can be obtained. When both TLS' and NDS are used, as shown in the previous example, the amount added is smaller than that of a dispersant using DSL, and there is less influence by the type of coal. This is thought to be because the ratio of lignin sulfonate in the reactant became high, which increased its affinity for coal. When using the conventional DSL (Japanese Patent Publication No. 58-34896), the limit was 30 parts of DSL compared to 100 parts of NS, whereas in the case of TLS' of the present invention, up to 50 parts can be used. Therefore, the amount can be increased to about 1.5 times the conventional amount.

Claims (1)

[Scope of Claims] 1. A dispersant for a coal/water chiller containing as an active ingredient a reaction product of a modified lignin sulfonate subjected to an oxidation reaction treatment, naphthalene disulfonic acid, naphthalene sulfonic acid, and formaldehyde. 2 The ratio of modified lignin sulfonic acid, naphthalene disulfonic acid, and naphthalene sulfonic acid is 10 to
The dispersant for coal/water slurry according to claim 1, wherein the dispersant is 50:5 to 20:100 parts.