JPH0236160B2 - KONODOSEKITANN MIZUSURARIIYOGENNENZAI - 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 reaffirmed, 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. Furthermore, in the coal gasification process, attempts are being made to supply coal to the gasification reactor in the form of a water slurry. However, with current technology, as the coal concentration increases, the coal thickens significantly and loses fluidity, making pumping difficult. On the other hand, lowering the coal concentration reduces transport efficiency, requires a dehydration process before combustion, and coal gasification
There are many problems because a sufficient reaction temperature cannot be obtained. JP-A-52-71506 and JP-A-56-21636 describe naphthalene sulfonic acid salts and their formalin condensates, but when these compounds are used alone, the viscosity-reducing effect is weak; At high coal concentrations of 61% or more, the viscosity increases rapidly and
Dilatancy occurs, making pumping difficult in practice. Although it is stable, coal sedimentation occurs and a hard cake is formed, which poses a practical problem. The present inventors have conducted intensive research on a thinner 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, thus providing a coal-water slurry that can be pumped even at high coal concentrations. Coal used in the coal-water slurry of the present invention includes anthracite coal, bituminous coal, sub-bituminous coal, brown coal, and cleaned versions thereof, but any coal may be used. In addition, 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 more than 70% by weight of 200 mesh coal, this particle size is This is a guideline for the particle size of pulverized coal. However, the thinner of the present invention is not affected by particle size and exhibits excellent effects on coal powder of any particle size. Cleaned coal is coal from which inorganic substances, such as ash and sulfur, have been removed. Examples of methods for cleaning coal include the oil agglomeration method (hereinafter referred to as the OA method),
There are methods such as flotation coal flotation method and heavy liquid separation method. However, methods other than these may be used and are not particularly limited. Regarding the OA method, after dry or wet pulverization of coal, a water slurry is prepared, and an appropriate amount of oil with a surfactant added if necessary is added, or after the coal is coated with the oil in advance, a water slurry is prepared. By adjusting and stirring, the difference in wettability of the organic and inorganic components of the coal to oil and water is utilized to selectively use the oil that wets the organic components of the coal as a binder to coagulate the organic components of the coal. On the other hand, since inorganic substances have a weak affinity with oil and are liberated in water, this method allows the inorganic substances to be removed at the same time by separating the water from the aggregated coal. The coal concentration in the coal-water slurry of the OA method is usually 10 to 50% by weight. The oil used in the OA method is 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 cracked residual oil, or various blended oils, and is generally used as a fuel. Oil used as a lubricant,
Mineral oil such as cleaning oil. Water-insoluble oils such as benzene, toluene, xylene, and animal and vegetable oils may also be used, but among these, heavy oils such as C heavy oil and tar residue oil are particularly preferred because they are inexpensive. It is generally sufficient to use this oil in an amount of 30% or less by weight of the coal in the coal-water slurry to be treated for mineral removal. In addition, 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 is also OA
Similar to the method, the organic components of the coal adhere to the oil film of the froth, but the inorganic components are released into the water and can be separated from the organic components of the coal. The oils used in the flotation method are terpineol, tar, A heavy oil, C heavy oil, light oil, and kerosene. Generally, several tens of weight percent or more of inorganic substances are removed from coal by the above method. If coal cleaned in this way is used, the effect of the additive of the present invention is significantly superior to coal that has not been cleaned, and a coal-water slurry with several points higher concentration can be obtained. In addition to this effect, the use of cleaned coal has other great benefits, such as suppressing boiler corrosion during combustion and reducing the burden on ash removal equipment and desulfurization equipment. Next, the thinner used in the coal-water slurry of the present invention is a thinner for high-concentration coal-water slurry used to reduce the viscosity of the coal-water slurry and improve fluidity and stability. (a) the aromatic nucleus may be substituted with a hydrocarbon group, hydroxyl group, or carboxyl group, (b) sulfonic acid of a polycyclic aromatic compound and a monocyclic aromatic compound, or (b) A formalin condensation product of a sulfonic acid of a polycyclic aromatic compound and a sulfonic acid of a monocyclic aromatic compound, or (c) A formalin condensation product of a sulfonic acid of a polycyclic aromatic compound and a monocyclic aromatic compound, or It is characterized by containing a salt and (b) a polyphosphate as essential components. More specifically, examples of the polycyclic aromatic compound which is component (a) of the thinner of the present invention include compounds having a naphthalene ring, an anthracene ring, and a phenanthrene ring. These polycyclic aromatic compounds or their sulfonic acids (component c) are, for example, naphthalene, anthracene, phenanthrene, methylnaphthalene, butylnaphthalene, propylnaphthalene, methylanthracene, naphthol, methylnaphthol, naphthoic acid, lignin, etc., and their sulfones. A monster can be given. Examples of the monocyclic aromatic compound or its sulfonic acid (component d) include benzene, phenol, cresol, butylphenol, nonylphenol, salicylic acid, benzoic acid, toluene, xylene, ethylbenzene, and sulfonated products thereof. That is, the thinner according to the present invention
Component (a) can be any combination of a polycyclic aromatic compound and a monocyclic aromatic compound that are capable of a sulfonation reaction and a condensation reaction with formalin. This (a)
The ingredients are a single polycyclic aromatic compound, a single monocyclic aromatic compound, or both a polycyclic aromatic compound and a monocyclic aromatic compound, which are sulfonated by a conventional method, and then sulfonated with formalin. After the condensation reaction, it can be produced by neutralizing as necessary to form a salt. However, the method is not limited to a specific method, and any method can be used as long as the desired compound can be obtained. In this case, the average degree of condensation is preferably 1.5 to 20,
More preferably, it is 2-10. When the average degree of condensation is outside this range, the viscosity-reducing effect of the coal-water slurry is weak. Furthermore, the composition ratio of c component and d component to be subjected to the reaction is (c component)/(d component) = 1/9 in molar ratio.
~9/1, preferably 3/7~8/2. When the composition ratio is outside this range, the viscosity-reducing effect of the present invention is weak, and it is difficult to increase the concentration of the coal-water slurry. Examples of the salt include alkali metal salts such as sodium and potassium salts, alkaline earth metal salts such as calcium salts, ammonium salts, and amine salts. (b) Component polyphosphate refers to two or more P
(oxidation number 5) and has a P-O-P bond. Specifically, sodium pyrophosphate,
Examples include sodium tripolyphosphate, sodium polymetaphosphate, potassium pyrophosphate, potassium tripolyphosphate, potassium polymetaphosphate, and the like. The thinner of the present invention contains at least one of the above components (a) and (b), and the blending ratio is (a) 5 to 95% by weight, (b) 95 to 5% by weight. % by weight, preferably (a) 20-80% by weight, (b) 80-20% by weight. The amount of the thinner of the present invention added is 0.01 to 5.0% by weight, preferably 0.03 to 5.0% by weight, based on the coal-water slurry.
The amount is 2.0% by weight, and excellent effects are achieved with this added amount. The fluidity limit of coal-water slurry is
Although it varies depending on the type and particle size of coal, in general, if a thinner is not added, the coal loses fluidity at a concentration of around 50% by weight, but when the thinner of the present invention is added, the viscosity decreases significantly. Therefore, it has fluidity even when the coal concentration is 61% by weight or more, especially 70% by weight or more. If even cleaner coal is used, the coal concentration increases 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 for producing a coal-water slurry and the method for adding a thinner, there are methods such as dry-pulverizing coal in advance and then mixing a thinner into an aqueous solution, or adding a thinner after making a coal-water slurry. There are methods such as adding coal, water, and a thinner to the mill and mixing the coal while crushing it, and methods that use cleaned coal instead of coal in each method. Any method can be implemented. The reason why the thinner of the present invention exhibits an excellent effect is that the special structure of component (a) causes it to strongly adsorb to the particle surface, and then electrostatic factors prevent the particles from agglomerating, making them stable as primary particles. become At the same time, it is thought that due to the dispersion due to the electrostatic repulsion of component (b), a remarkable additive effect is exhibited and an excellent viscosity-reducing effect is produced. In addition, if you use clean coal that has been deashed, the effect will further increase because deashing removes ash, which is highly hydrophilic and has fine particles with a large surface area. This is because the thinner of the present invention effectively acts on the coal surface with improved organicity, thereby making it possible to increase the coal concentration. 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 moreover, it is possible to create a highly concentrated coal-water slurry that can be transported by pump. Examples are shown below. In the examples, percentages are by weight. Example 1 Coal pulverized to a 200 mesh 80% pass was 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. moreover,
This slurry was poured into a 500 ml cylinder to a height of 18 cm, and after it was allowed to stand for one month, the coal concentration in the upper layer (1 cm from the top) and lower layer (1 cm from the bottom) 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 coal concentration ranges from 74 to
Even at 77%, the viscosity is 1100 to 2800 cP, and the fluidity is extremely good. In addition, even after the slurry was allowed to stand for one month, there was almost no sedimentation of the coal, and it was very stable. On the other hand, when a general anionic surfactant is added or when no thinner is added, the coal concentration
At 50%, the viscosity is over 20,000cP and there is no flow at all. In addition, when using polyphosphate alone or when a common low molecular weight inorganic salt is used as a PH adjuster in component (a), the viscosity thinning effect is extremely weak, with a viscosity of around 20,000 cP at a coal concentration of 60%, and no Doesn't flow. 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 coal concentrations in the upper and lower layers were measured in the same manner as in Example 1. 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 coal concentration increases to 78
Even at ~80%, the viscosity is 1200-2700 cP, which means low viscosity and good fluidity. In addition, the slurry is 1
Even after being left standing for a month, there is almost no coal settling and it is extremely stable. On the other hand, when a general anionic surfactant is added or when no viscosity reducing agent is added, the viscosity decreases at a coal concentration of 50%.
It becomes over 20,000cP and does not flow at all. In addition, when using polyphosphate alone or when a common low molecular weight inorganic salt is used as a PH adjuster in component (a), the viscosity thinning effect is extremely weak, and the viscosity is 20,000 cP at a coal concentration of 60%. Doesn't flow.

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Claims (1)

[Scope of Claims] 1. A thinning agent for highly concentrated coal-water slurry used to reduce the viscosity of coal-water slurry and improve fluidity and stability, which comprises: (a) aromatic nuclei are carbonized; (a) Sulfonic acids of polycyclic aromatic compounds and monocyclic aromatic compounds, or (b) Sulfones of polycyclic aromatic compounds, which may be substituted with hydrogen, hydroxyl, or carboxyl groups. an acid and a sulfonic acid of a monocyclic aromatic compound, or (c) a formalin condensation product of a polycyclic aromatic compound and a sulfonic acid of a monocyclic aromatic compound, or a salt thereof, and (b) a polyphosphate. A thinning agent for coal-water slurry characterized by containing it as an essential component. 2. The composition ratio of the polycyclic aromatic compound or its sulfonic acid (component c) which is component (a) and the monocyclic aromatic compound or its sulfonic acid (component d) is (component c)/ (d component) = 1/9~
The thinner for coal-water slurry according to claim 1, which has a viscosity of 9/1, preferably 3/7 to 8/2. 3. The thinner for coal-water slurry according to claim 1 or 2, wherein the formalin condensate has an average degree of condensation of preferably 1.5 to 20, more preferably 2 to 10. 4 The blending ratio of component (a) and component (b) is (a) 5 to 95% by weight,
(b) 95-5% by weight, preferably (a) 20-80% by weight, (b)
The thinning agent for coal-water slurry according to any one of claims 1 to 3, wherein the content is 80 to 20% by weight. 5. The thinning agent for coal-water slurry according to any one of claims 1 to 4, for use in a coal-water slurry having a coal concentration of 61% or more, preferably 70% or more. 6. The thinner for coal-water slurry according to any one of claims 1 to 5, wherein the coal is cleaned coal.