JPS6015495A - Dispersion stabilizer for aqueous slurry of dust coal - Google Patents

Abstract

PURPOSE:To provide the titled dispersion stabilizer having excellent standing stability and high fluidity, prepd. by adding ethylene oxide-contg. alkylene oxide to a polyamide compd. and incorporating a specified polyether compd. CONSTITUTION:The dispersion stabilizer for aqueous slurry of dust coal contains as effective component a polyether compd. which is prepd. by adding ethylene oxide-contg. alkylene oxide to a polyamide compd., contains polyoxyethylene chain segments in 40-95wt% of the total molecular weight and has an MW of 5,000-200,000. Preferred polyether compd. is a wholly or partly blocked ethylene oxide/propylene oxide adduct. Preferred derivs. of the polyether compd. are those obtained by esterification with a fatty acid or cationization of part or the whole of nitrogen atoms in the polyether compd.

Description

DETAILED DESCRIPTION OF THE INVENTION Unexploded IJI relates to a dispersion stabilizer for coal powder water slurries. More specifically, the present invention relates to a dispersion stabilizer for dispersing coal powder in water and stabilizing the dispersion into a state that can be transported by pipeline.

In recent years, petroleum, which has been the most widely used energy source, has reached the limit of its reserves and the resulting high price116
3, etc., the diversification of energy sources and securing a stable supply have become important issues. For these reasons, the effective use of coal, which has large reserves and is not unevenly distributed around the world, is being reconsidered. However, unlike petroleum, coal is a solid, so it cannot be transported by pipeline and is extremely disadvantageous in terms of handling. Furthermore, coal generally contains a larger amount of ash than petroleum, and there are problems such as a decrease in calorific value and processing of fryers.

For this reason, in order to improve the second drawback of handling, a method of powdering coal and dispersing it in water to form a slurry has been tested. However, in this case as well, if the coal m1 degree is increased, it will become thicker and lose its fluidity, and if the coal concentration is lowered, the transportation efficiency will decrease and the dewatering process will also be costly.
Not practical. This is because the coal particles in the coal-water slurry aggregate (in water), causing an increase in viscosity and a decrease in fluidity.

The smaller the coal particles in the water slurry, the better the dispersion stability, but the cost of pulverization increases as the degree of pulverization increases. Currently, the pulverized coal burned in thermal power plants has a particle size of 200 menonyu, 80% pass, or approximately 74 microns, so this particle size can be used as a guideline for the particle size of pulverized coal. is expected. When a surfactant, which is a dispersant, is added to the coal-water slurry, the surfactant force (adsorption) occurs at the interface between the coal particles and water, which loosens the coal particles and prevents them from agglomerating together. It is expected to have a protective effect and create a good dispersion state.

The present inventors have already developed a dispersant having such an effect (see Japanese Patent Application No. 1982-95173).

However, although such a dispersant improves fluidity, it is not necessarily satisfactory in practical use because the precipitate is compacted and a cake is formed when the dispersant is allowed to stand still.

The present inventors conducted intensive research to improve the static stability and flowability, which are the drawbacks of the conventional coal-water sludge IJ. They discovered a dispersion stabilizer and completed the present invention.

That is, the present invention uses an alkylene oxide containing ethylene oxide as an essential component in the polyamide compound, and the total weight of the polyoxyethylene chain portion is 40 to 9 of the total molecular weight.
5% by weight and a molecular weight of 5.000 to 200.0
00 polyether compound or its derivative alone, or it further contains as an active ingredient one or more selected from the group consisting of aliphatic alcohol, sorbitan fatty acid ester, and 7-lycoin compound as a second component. This is a dispersion stabilizer for water slurry of coal powder, which is characterized by the following. Further, the dispersion stabilizer of the present invention is a dispersion stabilizer for water sushi of coal powder, which is effective also for coal deashed by flotation method or underwater granulation method.

The dispersion stabilizer of the present invention uses as an essential component a polyether compound or a derivative thereof, which is a polyamide compound mixed with an alkylene oxide containing ethylene oxide.

Examples of the polyamide compound used in the present invention include reaction products of alkylene polyamines and dibasic acids, reaction products of nitrile or diamide and formamide, self-condensates of amino acids, and ring-opening polymers of lactams.

A polyether compound can be easily obtained by adding an alkylene oxide which essentially contains ethylene oxide to a polyamide compound by a conventional method.

Among these, it is particularly preferable to add ethylene oxide and propylene oxide in a block or partially block form, and the addition order may be in either order, but it is preferable to add propylene oxide (hereinafter abbreviated as PO) first. Good dispersion stability is shown when ethylene oxide (hereinafter abbreviated as EO) is added thereto.

Derivatives of the polyether compound include phosphorus oxide carboxyalkylated products or salts thereof, fatty acid esters, or dialkyl sulfates obtained by sulfating the terminal hydroxyl group of the polyether compound and reacting with zoζ sulfates, phosphorus pentoxide. Examples include cationized products such as alkyl halide, benzyl halide, etc.

In particular, there are compounds in which part or all of the nitrogen atoms of a suitably sized fatty acid ester or a polyether compound are cationized.

The molecular weight of the polyether compound or its derivative is 5.00
0-200. OQ O, preferably 1.0.00
0 to 10Q000, more preferably 30,000 to 80
,000 range. The total weight of the 0 chain portion is 40 to 95% by weight of the total molecular weight, preferably 80% by weight.
~95% by weight.

Further, as the aliphatic alcohol of the second component of the dispersion stabilizer of the present invention, specifically, an aliphatic alcohol having 6 to 12 carbon atoms is used, and examples thereof include octyl alcohol, 2-ethylhexyl alcohol, and lauryl alcohol. Examples of the sorbitan fatty acid ester include norbitan monolaurate, nrubitan monobalmide-1., sorbitan monooleate-1., and norbitan monostearate. Among the same components (b), silicone compounds include polydimethyl Zoroke IJ-7, dimethyl silicone oil, fluorosilicone oil, and the like.

The dispersion stabilizer of the present invention has a concentration of 0.0% with respect to the water slurry.
01-5.0% by weight, preferably 0.05-20% by weight
By adding it, coal particles can be dispersed in water.

The second component of the dispersion stabilizer of the present invention is an aliphatic alcohol, sorbitan fatty acid Nisdel, or a silicone compound.
The amount is 30% by weight or less, preferably 15 to 5% by weight based on the polyether compound derivative, and may be added to the coal slurry together with the polyether compound derivative, or may be added to the coal slurry separately.

The fluidity of a coal-water slurry generally varies depending on the type and particle size of the coal powder, but when no dispersion stabilizer is added, the viscosity increases rapidly when the coal jfA degree exceeds 30% by weight. On the other hand, when a predetermined amount of the dispersion stabilizer of the present invention is added, coal particles are dispersed, fluidity is significantly improved, and a highly concentrated slurry can be obtained. A slurry with excellent storage stability that does not form can be obtained. If the concentration of coal constituting the coal-water slurry is too low, the transportation efficiency will be poor and the dewatering process will also be expensive, making it meaningless.

If it is too large, the viscosity becomes too high, so it is generally 30 to 85% by weight, preferably 50 to 78% by weight, although it varies depending on the type of coal and the viscosity e.

Conventionally, various compounds have been proposed as dispersion stabilizers for coal water slurry, and examples of compounds similar to the present invention include, for example, ethylene oxide, a compound that absorbs active hydrogen,
Polyether compounds containing alkylene oxides such as propylene oxide have been proposed.
−． Publication No. 102994, JP-A-57-1.47595
Publication No.). However, in order to achieve a satisfactory effect with these conventional dispersion stabilizers, it is necessary to add a relatively large amount, and it is greatly influenced by the particle size of the coal, preparation conditions, etc. Yes, and if added during wet grinding, powder 1 + f, l! Since the fluidity decreases as the process progresses, it is necessary to increase the required amount of addition as the surface area increases.

The dispersion stabilizer of the present invention is a polyether compound or its derivative obtained by adding alkylene oxide to a polyamide compound, and it exhibits excellent effects with a relatively small amount added, and also has revolutionary performance that is not affected by particle size distribution or adjustment conditions. It has the following.

This is thought to be due to the fact that adsorption to the coal surface is dramatically improved by introducing an amide group, which is a hydrophobic group, into the molecule.

When the dispersion stabilizer of the present invention is further combined with a specific compound shown as a second component, it is possible to obtain an even lower viscosity and better fluidity due to their additive effects.

The coal used in the present invention may be of various types such as anthracite, bituminous coal, sub-bituminous coal, lignite, etc., and is pulverized. The particle size of this coal powder may be any particle size that allows direct combustion in the boiler, but the general particle size currently used in thermal power plants for this purpose is 200 mesh, with a pass rate of 70 to 90. % particle size.

The mixing order of coal, dispersion stabilizer, and water may be arbitrary, but the dispersion stabilizer may be dissolved or dispersed in water, and then coal may be added thereto to prepare the mixture using a suitable mixing device or crushing device.

The dispersion stabilizer of the present invention can be used in combination with other anionic surfactants or nonionic surfactants. For example, the present inventors have already invented the dispersion stabilizer for water slurry of coal powder according to the present invention, and are currently in the process of filing a patent application (Japanese Patent Application No. 54-95').
Defukuri/sulfonic acid formalin condensate, which is a dispersant for water slurry of coal powder, anionic surfactant such as lignin sodium sulfonate, polyoxyethylene norbitane fatty acid described in the specification of No. 1.73) If used in combination with a nonionic surfactant such as an ester or a cationic surfactant, even better dispersibility can be obtained.

Further, in the water slurry of coal using the dispersion stabilizer of the present invention, fatty acids such as oleic acid, amine compounds such as cyamylamine, amide compounds such as stearylamide, tributyl phosphate, etc. +7) IJ acid ester or aluminum stearate 1. By adding metal soaps such as, it is possible to make a stable slurry with less air bubbles.

Currently, consideration is being given to removing the ash content from coal by various methods and burning it as a deashed coal-water slurry in a heavy oil-fired boiler. Coal deashing methods at this time include a method that applies the principle of flotation and uses a collector and a foaming agent to retain the ash in water and adsorb the coal to the foam, and a method that collects the coal by adsorbing it to the foam. Underwater granulation method in which an emulsion is added and stirred to selectively recover coal by granulation (for example, JP-A-5:2-
No. 37901) is attracting attention. The dispersion stabilizer of the present invention exhibits extremely good dispersion stability even in coal slurry deashed by such a method. Also, in this case,
Hydrocarbon oil (e.g. diesel fuel oil,
The dispersion stabilizer of the present invention exhibits excellent performance without losing its dispersion effect even in systems where such hydrocarbon oils coexist.

The water slurry of coal powder obtained by adding the dispersion stabilizer of the present invention has good fluidity with little increase in viscosity even at high concentrations, and has good dispersion stability without forming hard cakes even after long-term storage. 'Keep a useless pipeline'? Ill+ transport, tank storage, and direct boiler combustion are possible. By using the dispersion stabilizer of the present invention, a water slurry of coal powder has a small final Q during production, a small increase in volume of the slurry, and thickening due to air bubbles is prevented, so that it has good properties. be able to.

EXAMPLES The present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

Example (1) Method for preparing deashed coal I) Method for producing deashed coal by underwater granulation method Daido coal with the following composition of 200 mesh 80% pass
428! ? 4ooi1 (containing 7.0% moisture) as a pure rice fraction is dispersed in water at room temperature and stirred to obtain a coal-water slurry.

20 tons of heavy oil was added to this mixture, and the mixture was heated at room temperature at 1000 rpm using a lab body spar (special mechanical processing section).
Stir for 30 minutes to demineralize and granulate. The mixture thus obtained was passed through an 8 mesh sieve to remove the ash,
A deashed and dehydrated granule (deashed charcoal A) was obtained by drying at 105°C. The residual ash content of this product is /J, 8 wt% (based on coal).

Met.

11) Method for producing deashed coal by flotation method Similar to 1), Daido coal 428y was dispersed in water in room/+14, and put into a 1i''■r type flotation machine with pine oil 0.5P for flotation treatment. Do it.

Then, the deashed coal slurry collected together with the foam is dehydrated under reduced pressure to obtain deashed coal B. The residual ash content of this product is 4.
Q wt% (coal standard).

Phantom Daido coal calorific value 7450I (cal/I(ii') (JIS M8
814) Ash content 89% (JIS M8812) Moisture 780% (J'IS M8811) Fixed carbon 60.0% (JIS M8812) Table 1 Test coal list (2) Water slurry preparation and fluidity evaluation Table 2 Disperse 1.87 g of the Mouse 6 compound in 97.7 y of water, and add 387 g of Datong charcoal of Sample Charan 1 shown in Table 1 little by little to this mixture at room temperature. After the entire amount was added, the mixture was stirred for 5 minutes at 5000 rpm using a homomixer (manufactured by Tokushu Kikakojobe) to prepare a coal-water slurry vI4.

The viscosity was measured at 25'C and was 2020 centivoise, indicating good fluidity. Also, the test coal shown in $1, the polyether compound derivatives shown in Table 2, and the polyether compound derivatives shown in Table 3, also provided by Tojiki.
The results are shown in Tables 4 and 5, including other Examples and Comparative Examples in which various combinations of the second components shown in Table 4 were used. Low viscosity indicates good fluidity.

(3) Evaluation of the stability of water slurry The stability of the slurry was determined at 3°1' and 6' after producing the slurry.
After standing still for 0 days, a stainless steel rod (weight: 502 mm) with a diameter of 5 nm was gently placed into the slurry and its sedimentation state was observed. The slurry prepared in (2) had good stability, and there was almost no compaction even after 0 days had passed. The results, including other Examples and Comparative Examples, are shown in Tables 4 and 5.

*2R = 34 indicates an alkylene group with 34 return primes.

*3 Indicates the I++ addition to the starting material.

*4 Weight ratio *5 Except for cationization, it is R1! The modification ratio to active hydrogen and cationization indicate the ratio to nitrogen.

Table 3 Second component

Claims (1)

[Scope of Claims] 1. An alkylene oxide containing ethylene oxide as an essential component is added to a polyamide compound, and the weight of the cuffs in the polyoxyethylene chain portion is 40 to 95% by weight of the total molecular weight, and the molecular weight is 5. 000~200. O
A dispersion stabilizer for a water slurry of coal powder, which is characterized by containing a polyether compound OO or a derivative thereof as an active ingredient. 2. The dispersion stabilizer for a water slurry of coal powder according to claim 1, wherein the polyether compound or its derivative is a block-like or partially block-like adduct of ethylene oxide and an alkylene oxide other than ethylene oxide. 3. The dispersion stabilizer for a water slurry of coal powder according to claim 1 or 2, wherein the alkylene oxides in the polyether compound or its derivative are ethylene oxide and propylene oxide. 4. Attraction of polyether compounds! The coal according to claims 1 to 3, wherein the -y form is a compound obtained by esterifying the terminal hydroxyl group of a polyether compound with a fatty acid or a compound obtained by cationizing the nitrogen atom of the polyether compound. Dispersion stabilizer for powder water slurry. 5a) An alkylene oxide containing ethylene oxide as an essential component is added to a polyamide compound, and the weight of the coated part of the polyoxyethylene chain is 40 to 95% by weight of the total molecular weight, and the molecular weight is 5.000 to 200. O
A dispersion stabilizer for an aqueous slurry of coal powder, characterized in that it contains as active ingredients one or more of a polyether compound or a derivative thereof, and b) a fatty 1M alcohol, a sorbitan fatty acid ester, or a silicone compound.