JPH0113518B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thinner for coal-water slurries.
More particularly, it relates to a thinning agent for dispersing pulverized coal in water to provide a highly concentrated coal-water slurry that can be pumped. In recent years, due to the depletion of petroleum resources, the use of coal has been reconsidered, and various methods of its use are being considered. However, unlike oil, coal is a solid and cannot be transported by pump. For this reason, various methods are being considered for pulverizing coal and dispersing it in water to form a water slurry. However, with current technology, this method
As the coal concentration increases, it becomes significantly thicker and loses its fluidity, making pumping difficult.
On the other hand, lowering the coal concentration reduces transportation efficiency and requires a dehydration process before combustion, which is not practical as it increases costs. JP-A-52-71506 and JP-A-56-21636 describe naphthalene sulfonic acid salts and their formalin condensates, but when these compounds are used, the viscosity-reducing effect is weak and the coal concentration is low. At high concentrations of 61% or more, the viscosity increases rapidly and dilatancy occurs, making pumping difficult in practice. The present inventors have conducted intensive research on a thinning agent for coal-water slurry that can fluidize highly concentrated coal-water slurry and enable pumping.
A thinning agent has been successfully developed that significantly reduces the viscosity of a coal-water slurry and thus provides a coal-water slurry that is pumpable even at high coal concentrations. By using the thinning agent of the present invention, coal can be fluidized with a small amount of water, making it possible to not only transport it by pump, but also to burn it in a boiler as it is.
The dehydration step before combustion can also be omitted. By using the thinner of the present invention, handling of coal becomes extremely simple, and its applications are greatly expanded. The coal used in the coal-water slurry is anthracite;
Any coal may be used, such as bituminous coal, sub-bituminous coal, brown coal, or cleaned versions thereof. Furthermore, the particle size of the coal in the water slurry may be any particle size as long as it is powder, but since the pulverized coal currently burned in thermal power plants is 70% or more of 200 mesh pass, this particle size is suitable for pulverized coal. This is a guideline for the particle size of However, the thinner of the present invention is not affected by particle size and exhibits excellent effects on coal powder of any particle size. In addition, the cleaned coal contains more inorganic substances than in the coal.
For example, ash and sulfur have been removed. Methods for cleaning coal include, for example, heavy liquid separation method, oil agglomeration method (hereinafter referred to as OA method), and coal flotation method. However, methods other than these may also be used and are not particularly limited. Regarding the OA method, coal is pulverized dry or wet, then a water slurry is prepared, and an appropriate amount of oil is added, or coal is coated with oil in advance, a water slurry is prepared, and the water slurry is stirred. Utilizing the difference in wettability of the organic and inorganic components of coal to oil and water, the organic components of coal are coagulated using oil that selectively wets the organic components of coal as a binder. On the other hand, since inorganic substances have a weak affinity with oil, they are liberated in water, so this method can simultaneously remove inorganic substances by separating water from coagulated coal. The coal concentration in the coal-water slurry of the OA method is usually 10-65%. The oil used in the OA method is generally crude oil or various fractions obtained from crude oil, such as kerosene, light oil, A heavy oil, B heavy oil, C heavy oil, etc., tar or shale oil, ethylene separation residual oil, or various blended oils. The oils used are mineral oils such as lubricating oils and cleaning oils. Water-insoluble oils such as benzene, toluene, xylene, and animal and vegetable oils may also be used, but heavy oils such as C heavy oil and tar residue oil are particularly preferred because they are inexpensive. This oil is generally sufficient in an amount of 20% or less of the coal in the coal-water slurry to be treated for mineral removal. The flotation coal washing method is an existing coal washing method in which a very small amount of oil is added to a pulverized coal-water slurry and stirred to create froth. This method also
As with the OA method, the organic components of the coal adhere to the oil film from the froth, but the inorganic components are liberated into the water and can be separated from the organic components of the coal. The oils used in the flotation method are turpine oil, tar, A heavy oil, C heavy oil, light oil, and kerosene. Generally, several tens of percent or more of inorganic substances are removed from coal by the above method. When using coal that has been cleaned in this way, the effect of the additive of the present invention is significantly superior to coal that has not been cleaned, and a coal-water slurry that is several points higher in concentration can be obtained. Furthermore, when cleaned coal is used, in addition to this effect, boiler corrosion during combustion is suppressed, and the burden on ash removal equipment and desulfurization equipment is reduced, among other great benefits. The thinner for coal-water slurry of the present invention contains a sulfonated polycyclic aromatic compound which may be substituted with a hydrocarbon group, and a compound having an imino group and/or a carbamoyl group or a thiocarbamoyl group. It contains as an essential component a co-condensate of a compound with aliphatic aldehyde or a salt thereof. Sulfonated polycyclic aromatic compounds that may be substituted with hydrocarbon groups include naphthalene,
These include sulfonated products such as alkylnaphthalene and anthracene, petroleum sulfonic acid, and lignin sulfonic acid. Among these, sulfonated products of naphthalene and alkylnaphthalene are most preferred. Examples of compounds having an imino group include guanidine, dicyandiamide, and biguanide, and examples of compounds having a carbamoyl group or thiocarbamoyl group include urea, alkylene urea, carbamate ester, and their corresponding thio compounds. Aliphatic aldehydes include formalin, glyoxal, and acetaldehyde, with formalin being commonly used. The thinning agent of the present invention can be produced by known synthetic methods. That is, polycyclic aromatic compounds, which may be substituted with hydrocarbon groups, are sulfonated using, for example, sulfuric acid, oleum, or sulfane;
As it is or after partial neutralization, a compound having an imino group and/or a compound having a carbamoyl group or a thiocarbamoyl group and an aliphatic aldehyde are added and co-condensed at a temperature of 60 to 110°C.
The resulting condensate may be made into a salt with an alkali metal such as sodium or potassium, an alkaline earth metal such as magnesium or calcium, ammonium or an amine. However, the thinning agent of the present invention is not limited by the manufacturing method, and any manufacturing method can be employed as long as the desired thinning agent can be obtained. The degree of condensation is preferably 1.5 to 50, more preferably 2.0 to 10. The thinning agent of the present invention is significantly superior to known naphthalene sulfonic acid formalin condensate additives in reducing the viscosity of coal-water slurry.
This is due to the difference in their chemical structures. That is, a known naphthalene sulfonic acid formalin condensate, for example, has the following repeating structure. On the other hand, the corresponding formalin cocondensate of naphthalene sulfonic acid and urea of the present invention has the following repeating structure. Thus, the reason for the better results is that the bulky naphthalene rings are separated by long spacer groups with nitrogen atom-containing functional groups rather than simply by mellelene groups. As described above, the thinning agent of the present invention contains as an essential component a condensate having the above structure using a compound having an imino group, a carbamoyl group, or a thiocarbamoyl group, and only those having these structures exhibit surprising effects. It demonstrates this. Furthermore, if you use clean coal that has been deashed, the effect will be further increased because deashing removes ash, which is highly hydrophilic and has fine particles with a large surface area, so organic matter is removed. This is because the thinner of the present invention effectively acts on the improved coal surface, thereby making it possible to increase the coal concentration. Such a thinner of the present invention is used in an amount of 0.01 to 5.0% by weight, preferably 0.03 to 2.0% by weight, based on the coal-water slurry.
Excellent effects can be achieved by adding % by weight. The fluidity limit of a coal-water slurry differs depending on the type and particle size of the coal, but generally, if a thinner is not added, fluidity will disappear at around 50% coal concentration, but with the thinner of the present invention, If added, the viscosity will decrease significantly, so if the coal concentration is 61% or more, especially 70%
The above also has fluidity. If cleaner coal is used, the coal concentration will increase by several points, typically 3 to 10 points. The thinner of the present invention can also be used in combination with other surfactants. Regarding the method of producing coal-water slurry and the method of adding a thinner, there are two methods: dry-pulverizing the coal in advance and then mixing the thinner into an aqueous solution, or adding the thinner after making the coal-water slurry. A method of adding coal, water, and a thinner to a mill and mixing it while crushing the coal, and a method of mixing using cleaned coal instead of coal in each method. can be implemented. The thinner of the present invention has an excellent effect of stably dispersing coal in water, and does not cause water separation even when left standing for a long period of time, for example, one month, and maintains a homogeneous coal-water slurry. There is. Thus, the thinner of the present invention can be used in an amount of 0.01 to 5.0% by weight, preferably 0.03 to 5.0% by weight, based on the coal-water slurry.
By adding only 2.0% by weight, the viscosity of the coal-water slurry can be significantly reduced and a highly concentrated coal-water slurry can be produced that can be pumped. Examples are shown below. In the examples, percentages are by weight. Example 1 Coal pulverized to a 200 mesh 80% pass is added to an aqueous solution containing a predetermined amount of the thinner shown in Table 1 with stirring at room temperature to prepare a coal-water slurry of a predetermined concentration. The viscosity of this slurry is 25℃
and observe the fluidity. Furthermore, after this slurry was allowed to stand for one month, the state of water separation was measured. The test results are shown in Table 2. As shown in Table 2, when the thinner of the present invention is added, the viscosity of coal is 72 to 77.
%, the viscosity is 1000 to 3000 cp, and the fluidity is extremely good. On the other hand, when a general anionic surfactant is added or no thinner is added, the viscosity becomes 20,000 cp or more at a coal concentration of 50%, and there is no flow at all. Furthermore, when a known sodium salt of naphthalene sulfonic acid formalin condensate was used, the viscosity was 10,000 cp at a coal concentration of 63%.

【table】

[Table] Example 2 A clean coal-water slurry of a predetermined concentration is prepared in the same manner as in Example 1 using cleaned coal. The coal particle size is 80% pass of 200 mesh. The viscosity of this slurry is measured at 25°C and the fluidity is also observed. After this slurry was allowed to stand for one month, the state of water separation was measured. The thinners of the present invention used in the test are shown in Table 1. The test results are shown in Table 3. As shown in Table 3, when the thinner of the present invention is added to the cleaned coal-water slurry, the viscosity is 1000 to 3000 cp even at a coal concentration of 76 to 80%, and the fluidity is extremely good. On the other hand, when a thinner other than the present invention is added or no thinner is added, the viscosity becomes 20,000 cp or more at a coal concentration of 50% and there is no flow at all. Furthermore, when a known naphthalene sulfonic acid formalin condensate Na salt was used, the viscosity was 10,000 cp at a coal concentration of 67%.

[Table] ○ Without water separation, × With water separation

Claims (1)

[Claims] 1. Highly concentrated coal used to reduce the viscosity of coal-water slurry and improve fluidity and stability.
A sulfonated polycyclic aromatic compound which may be substituted with a hydrocarbon group, and a compound having an imino group and/or a carbamoyl group or a thiocarbamoyl group, which is a thinner for water slurry. , a co-condensate with an aliphatic aldehyde, or a salt thereof as an essential component. A high-performance thinner for coal-water slurry. 2. The high performance thinner for coal-water slurry according to claim 1, wherein the sulfonated polycyclic aromatic compound is naphthalene sulfonic acid or alkylnaphthalene sulfonic acid. 3. The coal according to claim 1 or 2, wherein the compound having an imino group or the compound having a carbamoyl group or a thiocarbamoyl group is selected from urea, thiourea, dicyandiamide, guanidine, biguanide, and derivatives thereof. High performance thinner for water slurries. 4. A high performance thinner for coal-water slurry according to any one of claims 1 to 3, for use in a coal-water slurry having a coal concentration of 61% or more, preferably 70% or more. 5. A high-performance thinner for coal-water slurry according to any one of claims 1 to 4, wherein the coal is cleaned coal.