JPS5876493A - Viscosity-reducing agent for concentrated coal-water slurry - Google Patents

Abstract

PURPOSE:To provide a viscosity-reducing agent for concentrated coal-water slurry, containing a specific polyether compound or its specific esterified product as an essential component, and capable of improving the fluidity and the stability of the slurry and enabling the transportation of the slurry with a pump. CONSTITUTION:The objective viscosity-reducing agent contains a polyether compound having a molecular weight of 1,000-100,000, preferably 6,000-100,000 and obtained by the addition of an alkylene oxide such as ethylene oxide to an aliphatic aldehyde condensate of an aromatic compound having phenolic hydroxyl group, its sulfuric acid ester, or phosphoric acid ester, as an essential component. Said viscosity-reducing agent is added usually to a slurry having a coal concentration of >=61% (preferably >=70%).

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. However, with current technology, this method becomes difficult to pump as increasing the coal concentration significantly thickens the coal and loses its fluidity. −
Lowering the coal concentration on the λ side lowers transport efficiency and requires a dehydration step before combustion, which is expensive and impractical.

JP-A No. 54-33803 describes the addition of a polymeric surfactant to a fine ore slurry, but it only specifically exemplifies polyacrylamide and polyethyleneimine, and It is intended for low concentration fine ore slurry.

The present inventors fluidized a highly concentrated coal-water slurry,
We have conducted extensive research on the viscosity reducing agent for coal-water slurries that enables pumping, and have discovered that adding a small amount can significantly reduce the viscosity of coal-water slurries.As a result, we have developed coal that can be pumped even at high coal concentrations. - Succeeded in developing a viscosity reducing agent that provides water slurry.

By using the thinner 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, and also eliminate the dehydration step before combustion. be able to. By using the thinning agent of the present invention, handling of coal becomes extremely simple, and its applications are greatly expanded.

The coals used in the coal-water slurry include anthracite, bituminous coal,
Any type of coal may be used, such as submersible coal, bituminous coal, brown coal, or cleaned versions thereof.

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 0% pass or higher, this particle size is fine. This is a guideline for the particle size of charcoal. 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 heavy liquid separation method and the oil aggregation method (hereinafter referred to as OA).
There are methods such as flotation method) and 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 the coal is coated with oil in advance, a water slurry is prepared and stirred. Utilizing the difference in wettability between the organic and inorganic components of coal with respect to oil and water, the organic components of coal are selectively agglomerated using oil that dissolves the organic components of coal as a binder. On the other hand, inorganic substances have a weak affinity with oil, so
Since it is liberated in water, this method can remove inorganic substances at the same time by separating the water from coagulated coal. OA
The coal concentration in the coal-water slurry of the method is usually lO~65%
It is.

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 pre-oil, ethylene cracked residual oil, or various blended oils. Mineral oils include oils used as fuel, 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. It is generally sufficient to use this oil in an amount of 30% 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 the pulverized coal-water slurry and stirred to create foam.
Generate 70 spaces. Similar to the OA method, in this method, the organic components of the coal adhere to the 70% oil film, but the inorganic components are liberated in the water.
This is a method that can separate coal organic components.

The oils used in the flotation method are - terpine 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 manner, the effect of the thinning agent of the present invention is significantly superior to that of 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.

The thinner for coal-water slurry of the present invention has a molecular weight of 1000 and is obtained by adding an alkylene oxide to an aliphatic aldehyde condensate of an aromatic compound having 7 etheric hydroxyl groups.
It is characterized by containing from 100,000 to 100,000, preferably from 6,000 to 100,000, of a polyether compound, or a sulfuric acid ester or phosphoric acid ester of the polyether compound.

Examples of aromatic compounds having a phenolic hydroxyl group include: 1) 7-enols and substituted phenols such as phenol, cresol, xylenol, butylphenol, nonylphenol, amino 7-egul, and hydroxybenzoic acid; 2) 7-enol, methylnaphthol, and butyl phenol; Naphthol and substituted substances such as naphthol and octylnaphthol 7
Tolls 3) Polyhydric 7-tolls such as polyhydric phenols such as catechol, resorcinol, and pyrogallol nato; 5) Condensed phenols such as bisphenol A and bisphenol S.

Examples of the aliphatic aldehyde include ζ formalin, acetaldehyde, glyoxal, etc., with formaldehyde being common.

As the alkylene oxide, ethylene oxide, propylene oxide, butylene oxide, etc. are used.
These may be used alone or in combination of two or more types.
In the case of more than one species, the arrangement may be either block polymerization type or random polymerization type, but block polymerization type is common. In particular, a polyether compound containing ethylene oxide as an alkylene oxide and having a content of 10 to 95% by weight, preferably 30 to 90% by weight of the total alkylene oxide, or a sulfuric acid ester or phosphoric acid ester thereof, exhibits the Taleta effect. Demonstrate.

The sulfuric acid ester or phosphoric acid ester of a polyether compound includes free esters and salts, and the cation components that form the salt include inorganic cations such as sodium, potassium, calcium, magnesium, and ammonia;
Rice can also be prepared using organic cations such as various amines and quaternized amines.

The polyether compound may be produced by first condensing an aromatic compound having a phenolic hydroxyl group with an aliphatic aldehyde and then adding an alkylene oxide, or by first condensing an aromatic compound having a phenolic hydroxyl group with an alkylene oxide. It is also possible to add alkylene oxide to and then condense using an aliphatic aldehyde, but the former is common. The sulfuric acid esterified product or the phosphoric acid esterified product is obtained by sulfuric acid esterification or phosphoric acid esterification of the polyether compound using sulfuric acid, oleum, chlorosulfonic acid, sulfan, sulfamic acid, phosphorus pentoxide, phosphoric acid, etc. using a conventional method.
If necessary, it can be produced by neutralizing it to form a salt. However, the thinning agent of the present invention is not limited to those obtained by a specific manufacturing method, and any manufacturing method can be employed as long as the desired thinning agent can be obtained. The degree of condensation with the aliphatic aldehyde is preferably 1.5 to 50, more preferably 20 to 30.

The reason why the viscosity reducing agent of the present invention exhibits an excellent effect is that after it is strongly adsorbed to the particle surface due to its special structure, the numerous ether bonds hydrate the surrounding water and this water acts like a lubricating oil. It is thought that the coal particles become stable as primary particles and have improved fluidity. At the same time, a significant decrease in viscosity occurs.

In addition, if you use clean coal that has been deashed, the effect will be further improved because deashing removes ash, which is highly hydrophilic and has fine particles with a large surface area, resulting in improved organicity. This is because the thinner of the present invention acts effectively on the surface, thereby increasing the coal concentration.

The thinning agent of the present invention has a zero viscosity for coal-water slurry.
．． Excellent effects can be achieved by adding 0.01 to 5.0% by weight, preferably 0.03 to 2.0% by weight. Coal-
The fluidity limit of the water slurry varies depending on the type and particle size of the coal, but generally speaking, unless a thinner is added, the coal concentration will be 5.
Although it loses fluidity at around 0%, the viscosity decreases significantly when the thinner of the present invention is added, so it has fluidity even when the coal concentration is 61% or more, especially 70% or more. If cleaner coal is used, the coal concentration increases by several points, generally 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 the aqueous solution, or adding the thinner after making the coal-water slurry. There is a method of adding coal, a method of adding coal, water, and a thinner to the mill and mixing while crushing the coal, and a method of mixing using cleaned coal instead of coal in each method. Any method can be used, such as the method of

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 is preferably 0.01 to 5.0% by weight, preferably 0.03 to 2.0% by weight, based on the coal-water slurry.
Addition of only 0% by weight can significantly reduce the viscosity of the coal-water slurry and create a highly concentrated coal-water slurry that can be pumped.

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

Example 1 Into an aqueous solution containing a predetermined amount of the thinner shown in Table 1,
Coal pulverized to 0 mesh 80% pass is added at room temperature with stirring to prepare a coal-water slurry of a predetermined concentration. The viscosity of this slurry was measured at 25°C, and the fluidity was observed. 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 is 13QO to 2900 cp even at a coal concentration of 72 to 77%, and the fluidity is extremely good. On the other hand, when a general anionic surfactant is added or 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.

The thinner of the present invention significantly reduces the viscosity of the coal-water slurry, making it possible to form a highly concentrated coal-water slurry, and also significantly improves the stability of the coal-water slurry, allowing it to stand still for more than one month. However, no coal settling occurs, and no water separation occurs at all.

(The following is a blank space) Example 2 A cleaned 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 200 mesh 80% bath. 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 1300 to 2800 cp even at a coal concentration of 76 to 80%, and the fluidity is extremely good. - If a thinner other than the strength wood invention is added or if no thinner is added, the viscosity will be 20% at a coal concentration of 50%.
．． 000 cp or more and does not flow at all.

(Margin below)

Claims (5)

[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 is an aliphatic aldehyde of an aromatic compound having a phenolic hydroxyl group. A coal-water slurry containing as an essential component a polyether compound having a molecular weight of 1,000 to 100,000 obtained by adding alkylene oxide to a condensate, or a sulfuric acid ester or phosphoric acid ester of the polyether compound. Thinning agent. (2) The thinner for coal-water slurry according to claim 1, wherein the polyether compound has a molecular weight of 6,000 to 10,000. (3) Contains ethylene oxide as alkylene oxide, the content of which is 10 to 9 of the total alkylene oxide
Thinning agent for coal-water slurries according to claim 1 or 2, which is 5% by weight, preferably 30 to 90% by weight. (4) A thinning agent for coal-water slurry according to any 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) The thinner for coal-water slurry according to any one of claims 1 to 4, wherein the coal is cleaned coal.