JPS6026091A - Viscosity depressant for concentrated aqueous slurry of coal - Google Patents

Abstract

PURPOSE:To provide the titled viscosity depressant consisting of a formalin condensate (salt) of a specified compd. and a polyphosphoric acid salt, which reduces the viscosity of coal/water slurry when added in a small amt. and makes pumping of conc. slurry possible. CONSTITUTION:A polycyclic aromatic compd. (e.g. naphthalene) and/or a monocyclic aromatic compd. (e.g. benzene) [wherein the aromatic uncleus may be substd. with a hydrocarbon, hydroxyl or carboxyl group] [in case of a mixt., the molar ratio is 1:9-9:1] is sulfonated and is made to undergo condensation reaction with formalin, followed by neutralization when necessary, to obtain a formalin condensate having an average degree of condensation of 1.5-20 or salt thereof. The viscosity depressant is prepd. by blending 5-95wt% condensate (salt) with 95-5wt% polyphosphoric acid salt (e.g. sodium pyrophosphate). It is added in an amt. of 0.01-5.0wt% to a coal/water slurry having a coal concn. of 61wt% or higher.

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 oil resources, the use of coal has been reconsidered.
Various ways of using it 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. Also,
In the coal gasification process as well, attempts are being made to supply coal to the gasification reactor in the form of this slurry.

However, with current technology, as the coal concentration increases, the viscosity increases significantly and fluidity disappears, making pumping difficult. On the other hand, lowering the coal concentration lowers the transport efficiency, requires a dehydration step before combustion, and coal gasification has many problems, such as the inability to obtain a sufficient reaction temperature.

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, their viscosity-reducing effect is weak, and coal At a high concentration of 61% or more, the viscosity increases rapidly and dilatancy occurs, making pumping difficult. Although it is stable, coal sedimentation occurs and a bar cake is formed, which poses a problem in practical use.

The present inventors fluidized a highly concentrated coal-water slurry,
We have conducted intensive research into a thinning agent for coal-water slurry that enables pumping.Adding a small amount can significantly reduce the viscosity of coal-water slurry, making pumping possible even at high coal concentrations. "We have successfully developed a thinning agent that provides a highly efficient coal-water slurry.

Coal used in the coal-water slurry of the present invention includes anthracite, bituminous coal, sub-bituminous coal, lignite, 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 200 mesh pass 70% by weight or more, this The particle size 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 Oil Agg]
There are methods such as on method (hereinafter referred to as OA method), flotation method, and heavy liquid separation method. However, methods other than these may be used, and the method is not particularly limited.

○ Regarding the Δ method, after dry or wet pulverization of coal, a water slurry is prepared, and if necessary, an appropriate amount of oil with a surfactant added thereto is added, or the coal is coated with the above-mentioned ura in advance, and then water slurry is prepared. By adjusting and stirring the slurry, the organic content of the coal is selectively wetted by utilizing the difference in wettability of the organic content of the coal and the inorganic content to oil and water.The oil is used as a binder to cause agglomeration of the organic content 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. OA method coal
The coal concentration in the water slurry is usually 10-50% 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 residue, or various blended oils, and is generally used as a fuel. Mineral oils such as oils used as oils, lubricating oils, and cleaning oils. Water-insoluble oils such as benzene, 6-1-luene, 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. Generally, it is sufficient to use this water in an amount of 30% or less relative to the coal in the coal-water slurry to be treated for inorganic matter 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 the pulverized coal-water slurry and foamed by stirring.
Generate floss. Similar to the OA method, in this method, the organic content of coal adheres to the froth oil film, but the inorganic substances are liberated in the water and can be separated from the organic content of coal.

The oils used in the flotation method are terpineol, tar, heavy oil, C heavy oil, light oil, and kerosene.

It is common to remove more than several tens of percent of inorganic substances from coal by the method described in 1.

If coal cleaned in this way is used, the effect of the additive of the present invention is significantly superior to that of coal that has not been cleaned, and in addition, a highly concentrated coal-water slurry can be obtained in several points. When using cleaned coal, in addition to this effect, boiler corrosion during combustion is suppressed, and the burden on ash removal equipment and desulfurization equipment is reduced, which is a very large advantage.

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. There it is.

(a) the aromatic nucleus may be substituted with a hydrocarbon group, a hydroxyl group, or a carboxyl group, (b) a 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) polyphosphate 8- as essential components.

More specifically, the polycyclic aromatic compound which is the component (a) of the thinner of the present invention includes a naphthalene ring, an 1-helical ring,
Examples include compounds having a phenanyl ring.

These polycyclic aromatic compounds or their sulfonic acids (
Component C) is, for example, naphthalene, an-1-racene, phenan-1-rene, methylnaphthalene, butylnaphthalene,
Propylnaphthalene, methylanthracene, nano 1--
Examples include methyl nano-1, methyl nano-1, nano-1, engineering acids, lignin, and sulfonated products thereof. The monocyclic aromatic compound or its sulfonic acid (component d) is, for example, benzene,
Examples include phenol, cresol, butylphenol, nonylphenol, salicylic acid, benzoic acid, 1-luene, xylene, ethylbenzene, and their sulfonated products.

That is, component (a) of the viscosity reducing agent according to the present invention 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. be. Component (a) is obtained by sulfonating a polycyclic aromatic compound, a monocyclic aromatic compound alone, or both a polycyclic aromatic compound and a monocyclic aromatic compound by a conventional method. It can be produced by subjecting this to a condensation reaction with formalin, and then neutralizing it 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 1.5-20, more preferably 2-10. When the average degree of condensation is outside this range, the effect of reducing the viscosity 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 to 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 to potassium and potassium, alkaline earth metal salts such as calcium, 10-ammonium salts, and amine salts.

The polyphosphate as component (b) refers to one containing two or more P (oxidation number 5) and having a P-○-13 bond. Specifically, there are 1-lium pyrophosphate, 1-lium 1-lipolyphosphate, 1-lium polymetaphosphate, potassium pyrophosphate, potassium 1-helipolyphosphate, potassium polymetaphosphate, and the like.

The thinning agent of the present invention is one in which at least one component (a) and one component (b) are blended in 1. )95-
5% by weight, preferably (a) 2(1-80% by weight, (b
) 80-20% of the focus.

The amount of the thinner of the present invention added is 0.000 to the coal-water slurry. OI ~5.0% by weight, preferably 0.03-2.
It is 0% by weight, and excellent effects are exhibited with this added amount. The fluidity limit of a coal-water slurry varies depending on the type and particle size of the coal, but in general, unless a thinner is added,
Fluidity disappears when the coal concentration is around 50% by weight, but if the viscosity reducing agent of the present invention is added, the viscosity decreases significantly. It also has liquidity. If even cleaner coal is used, the coal concentration will increase by several points.
-1 Generally increases by 3 to 10 points 1-.

The thinning agent 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 thinning agent, the coal is dry-pulverized in advance, and then the thinning agent is There are two methods: mixing a viscosity agent into an aqueous solution, adding a thinning agent after making a coal-water slurry, and adding coal, water, and water into a mill.
Any method can be used, such as adding a thinning agent and mixing the coal while pulverizing it, or using cleaned coal instead of coal in each method.

The reason why the viscosity reducing agent of the present invention exhibits excellent effects is (a)
After being strongly adsorbed to the particle surface due to the special structure of the ingredients,
Electrostatic factors prevent particles from aggregating and stabilize them as secondary particles. 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 be further increased by deashing.
This is because the thinning agent of the present invention effectively acts on the coal surface, where organic properties have been reduced, by removing ash, which is highly hydrophilic and has a large surface area due to fine particles, thereby reducing the coal concentration. It is possible to measure the increase in -.

The thinner of the present invention has an excellent effect of stably dispersing coal in water, and even if it is left standing for a long period of time, for example, one month, it does not cause water separation and maintains a homogeneous coal-water slurry. There is.

Thus, the thinner of the present invention is preferably 0.01 to 5.0% by weight, preferably 0.03 to 2.0% by weight, based on the coal-water slurry.
Adding only 0% by weight can significantly reduce the viscosity of the coal-water slurry and make the coal-water slurry highly concentrated and pumpable.

Examples are shown below. In the examples, percentages are by weight.

13-Example 1 ・Into an aqueous solution in which a predetermined amount of the thinner shown in Table 1 is dissolved, 2
Coal pulverized to 80% pass was added at room temperature with stirring to prepare a coal-water slurry of a predetermined concentration. The viscosity of this slurry is measured at 25°C and the fluidity is observed. Furthermore, this slurry was
After placing it in the IIQ cylinder to a height of 18 cm and allowing it to stand for one month, the coal concentration in the second layer (from the second part to 1c+++) and the lower layer (Icm 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 viscosity is 1100 to 2800 cP even at a coal concentration of 74 to 77%, and the fluidity is extremely good.

Further, even after the slurry has been allowed to stand for one month, there is almost no sedimentation of the coal, and it is extremely stable. On the other hand, when a general anionic surfactant is added or no thinning agent is added, the viscosity is 20% at a coal concentration of 50%.
000 c P or more, and there is no flow at all.

14- In addition, when using polyphosphate alone or when a common low molecular weight inorganic salt is used as a regulator in component (a), the viscosity-reducing effect is extremely weak, and the viscosity decreases to 2 at a coal concentration of 60%.
It is around 0.0OOcP and does not flow at all.

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 concentration in the second layer and the F layer was 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 viscosity is 1200 to 2700 cP even when the coal concentration is 78 to 80%, resulting in a low viscosity and good fluidity. In addition, the slurry is extremely stable with almost no coal settling even after it has been allowed to stand for one month. On the other hand, when a general anionic surfactant is added or when no thinning agent is added, the viscosity becomes 20,000 cP or more at a coal concentration of 50%, and there is no flow at all.

In addition, when using polyphosphate alone or when a general low molecular weight inorganic salt is used as a pH adjuster in component (a), the viscosity-reducing effect is extremely weak, and the viscosity is 20,000 c at a coal concentration of 60%. P and does not flow at all.

18 Kaisho GO-26091 (6) 14 Opening Day, UGO-2GO91 (7) JP-A-Sho GO-26091 (8) i

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, comprising: (a) aromatic nuclei; may be substituted with a hydrocarbon group, hydroxyl group, or carboxyl group; (a) Sulfonic acid of a polycyclic aromatic compound and a monocyclic aromatic compound, or (b) A polycyclic aromatic compound. A sulfonic acid and a sulfonic acid of a monocyclic aromatic compound, or (c) a formalin condensate of a polycyclic aromatic compound and a sulfonic acid of a monocyclic aromatic compound, or a salt thereof, and (b) a polyphosphate. 1- A thinning agent for coal-water slurry, characterized in that it contains as an essential component. The composition ratio of the compound or its sulfonic acid (component d) is (component C)/(component d) = I/9 to 9/]
, preferably from 3/7 to 8/2.
The thinner for coal-water slurry described in section 1). (3) The average degree of condensation of the formalin condensate is preferably 1
．． The thinning agent for coal-water slurry according to claim (1) or (2), which has a molecular weight of 5 to 20, more preferably 2 to 10. (4) The blending ratio of component (a) and component (b) is (a) 5 to
95 weight%, (b) 95-5% by weight, preferably (a)
(b) 80-20% by weight; (b) 80-20% by weight; (b) 80-20% by weight; (5) The coal 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. A thinner for slurry. (6) The coal according to any one of claims (1) to (5), wherein the coal is cleaned coal.
Thinning agent for water slurry.