JPS6147196B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a dispersant for coal slurry. More specifically, the present invention relates to a dispersant for coal slurry that disperses coal powder in water at a high concentration so that it can be transported by pipeline, stored, and directly combusted. In order to improve the fluidity of highly concentrated coal-water slurries, it has been known to use a combination of polymeric substances and low-molecular surfactants, or to add them to sulfonates, sulfate ester salts, and copolymerized substances. , these have low viscosity even in water slurry with a coal concentration of 60% by weight.
High-concentration coal slurry with a concentration of 70% by weight or more will only reduce to 1200CP, and the viscosity will become too high for practical use.Also, there are drawbacks such as coal separation and sedimentation during storage. The present inventors have proposed a method that does not have the above drawbacks and has a coal concentration of 50
It has a sufficiently low viscosity even when it is more than 60% by weight (preferably more than 60% by weight), and not only can it be efficiently transported by pipeline, but also maintains good fluidity without separating or settling during long-term storage. As a result of intensive studies to find a dispersant for lime slurry containing high-concentration coal that can be directly combusted, it was discovered that the above object could be achieved by using a specific dispersant, and the present invention was achieved. That is, the present invention provides a dispersion for lime slurry consisting of oil-free coal and water, characterized in that it contains a nonionic surfactant consisting of a polyoxyalkylene ether of pentaethylenehexamine or higher polyalkylene polyamines. It is a drug. The polyamine in the polyoxyalkylene ether used in the present invention includes:
(Alkyl)polyalkylene polyamines, aromatic polyamines, or ring polyamines can be used. As the (alkyl) polyalkylene polyamine, those represented by the following general formula (1) (excluding dialkylene triamine, trialkylene tetramine, tetraalkylene pentamine, and N-alkylated derivatives thereof) can be used. [In the formula, R ₁ is an alkylene group having 2 or more carbon atoms, usually 2 to 10 carbon atoms, preferably 2 to 6 carbon atoms, and R' is hydrogen or a linear or branched saturated alkylene group having 1 to 30 carbon atoms. or an unsaturated alkyl group, preferably hydrogen or a straight chain or branched saturated or unsaturated alkyl group having 6 to 20 carbon atoms, n ₁ is usually an integer up to 20, preferably up to 10. ] Examples of the (alkyl) polyalkylene polyamine represented by the above general formula (1) include polyethylene polyamine (pentaethylenehexamine to decaethylene undecamine, etc.), polypropylene polyamine (nonapropylene decaamine, etc.), polybutylene polyamine, and poly(pentaethylene hexamine to decaethylene undecamine). methylene) polyamine, poly(hexamethylene) polyamine; and N-
Examples include alkyl substituted products. Among these, preferred are polyethylene polyamine and polypropylene polyamine, and particularly preferred is pentaethylene hexamine. Two or more of these (alkyl) polyalkylene polyamines may be used in combination. The oxyalkylene units constituting the polyoxyalkylene ether used in the present invention include oxyethylene groups, oxypropylene groups, oxybutylene groups, oxy(phenyl)ethylene groups, oxy(halo)ethylene groups, and two types thereof. The above combination systems can be mentioned. Those having an oxyethylene group as at least a part of the oxyalkylene group, especially an oxyethylene group and a carbon number of 3
Combination systems with the above oxyalkylene groups (especially oxypropylene groups) are preferred. The above-mentioned polyoxyalkylene ether can be produced by a known method, and the above-mentioned condensate is added with alkylene oxide (ethylene oxide, propylene oxide, 1.
2-, 2, 3-, 1, 3- or 1, 4-butylene oxide, styrene oxide, epichlorohydrin, etc.) in the presence of a catalyst (basic catalyst such as caustic potash, trimethylamine, or acidic catalyst such as boron fluoride). It can be produced by adding it to. Addition of alkylene oxide can be carried out by single addition, addition by mixing two or more types (random addition), sequential addition (block addition), or a combination of random addition and block addition. or a combination of this and random addition) is preferred. As the above polyoxyalkylene ether,
Examples include those represented by general formula (3). Y(-G-H) _l (3) [In the formula, Y is a polyamine or/and polyamide residue, G is a polyoxyalkylene chain, and l is an integer of 5 or more, usually 5 to 120, preferably 5 to 60. Preferably it is 5-30. ] In general formula (3), polyoxyalkylene chain G
as randomly added mixed polyoxyalkylene chains (MA); and -Q-E-, -E-Q
-, -E-Q-E- and -Q-E-Q'-(E,
E' represents a hydrophilic polyoxyalkylene chain, and Q and Q' represent hydrophobic polyoxyalkylene chains. ) block-added polyoxyalkylene chains. In the above general formula (3), the random addition type mixed polyoxyalkylene chain (MA) of G includes adducts of mixed alkylene oxides of ethylene oxide and the above alkylene oxides other than ethylene oxide. Mixed alkylene oxides include, for example, a mixture of ethylene oxide and propion oxide, a mixture of ethylene oxide, propion oxide and 1,2-butylene oxide, a mixture of ethylene oxide and styrene oxide, a mixture of ethylene oxide and 1,3-butylene oxide, etc. Preferred is a mixture of ethylene oxide and propylene oxide. The oxygen/carbon atom ratio of the mixed alkyl oxide is preferably 0.4 or more. The l MAs may be the same or different. In general formula (3), the hydrophobic polyoxyalkylene chains Q and Q' in the block addition type polyoxyalkylene chain of G and the hydrophilic polyoxyalkylene chains E and E' are the hydrophobic polyoxyalkylene chains Q and , Q' has a polyoxypropylene chain -
(C ₃ H ₆ O) _s and mixed polyoxyalkylene chains (especially those mainly composed of oxypropylene groups) with an oxygen/carbon atom ratio of 0.43 or less, hydrophilic polyoxyalkylene, chains E and E' Contains polyoxyethylene chains - (C ₂ H ₄ O) _t - and mixed polyoxyalkylene chains with a carbon/carbon atom ratio greater than 0.43 (especially polyoxyethylene/oxypropylene chains mainly composed of oxyethylene groups) . l E, Q, E', Q' may be the same or different. Some of l E, Q, E', and Q' may not exist. (It is sufficient if the average composition is the above structure.) Among the block addition type polyoxyalkylene chains, preferred is the formula
-G-H in (3) is -Q-E-H and -E-Q-
E'-H. The oxygen/carbon atom ratio of all polyoxyalkylene chains is preferably 0.4 or more. Hydrophilic polyoxyalkylene chain E in the block addition type polyoxyalkylene ether,
The ratio (total weight ratio) of E′ and hydrophobic polyoxyalkylene chains Q and Q′ is usually 1:1 to
The ratio is 999:1, preferably 3:2 to 99:1. The molecular weight of the polyoxyalkylene ether used in the present invention is usually 5,000 to 200,000, preferably
6000-180000. The number of oxyalkylene units (number of moles of alkylene oxide added) per active hydrogen is preferably 10 to 800 moles, more preferably 15 to 750 moles. If the molecular weight of the above polyoxyalkylene ether exceeds 200,000, the viscosity of the coal-water slurry will not be sufficiently reduced, and in the case of the polyoxyalkylene ether of the above polyamine, if the molecular weight exceeds 100,000, the viscosity of the coal-water slurry will decrease. If the molecular weight is not lowered sufficiently and the molecular weight becomes smaller than 5000, the coal will not be dispersed in water and cannot be made into a slurry. The content of oxyethylene groups in the above polyoxyalkylene ether is 50 to 99.7% by weight, especially 51% by weight.
~99% by weight is preferred. Even if it is less than 50% by weight or more than 99.7% by weight, the dispersion force for dispersing coal in water becomes small and a coal-water slurry cannot be obtained, which is not preferable. The ratio of ethylene oxide to other alkylene oxides (total weight ratio) in the polyoxyalkylene ether is usually 1:1 to 999:1, preferably 3:2 to 99:1. The dispersant of the present invention can be added to water in a high concentration (for example, 50% by weight or more) by adding it in an amount of usually 0.01 to 5%, preferably 0.05 to 2%, based on the weight of coal in the coal-water slurry. Coal particles can be dispersed. Generally, it depends on the type and particle size of coal powder, but if no dispersant is added,
If the coal concentration exceeds 30% by weight, not only will fluidity be lost, but also dispersants other than those of the present invention, such as dihydric alcohols, ethylenediamine, and substances containing ester bonds (such as castor oil, sorbitan mono- or tri- Even if alkylene oxide adducts such as fatty acid esters are added, if the coal concentration exceeds 60% by weight, fluidity will be lost, and when stored, the coal will separate and settle in the lower layer, making it impractical. On the other hand, when a predetermined amount of the dispersant of the present invention is added, the coal particles are dispersed in water, and the fluidity is improved, and the fluidity is good even when stored for a long period of time (for example, one week or more). If the concentration of coal constituting the coal-water slurry is too low, the transportation effect will be poor, the dehydration process will be expensive, and direct combustion will not be possible, making it meaningless. Also, if it is too large, the viscosity will become too high and it will not form into a slurry, so it will vary depending on the type and particle size of the coal, but usually 50%
or more (especially 50 to 95%), preferably 60 to 90%. The dispersant of the present invention may be used in Japanese Patent Application No. 1983-
Polyoxyalkylene ether of polyhydric alcohol (a) described in specification No. 140570, polyoxyalkylene ether of monohydric alcohol (b) described in specification of Japanese Patent Application No. 145098/1980, Japanese Patent Application No. 148197/1982 Polyoxyethylene ether (c) of monohydric alcohol described in the specification and/or polynuclear polyhydric phenol described in the patent application dated October 20, 1981 (title of invention "Dispersant for lime slurry") oxyalkylene ether (d) in various proportions, for example, from 1:0 to 1:0 by weight.
They can be used together at a ratio of 1:100 (especially 20:1 to 1:20). The dispersant of the present invention may be used alone or in the above (a), (b), and (c).
It is preferable to use it in combination with and/or (d), but other dispersants can be used in combination if necessary. Other dispersants include JP-A-56-21639, JP-A-56-20090, JP-A-54-33803, JP-A-56-57889, and JP-A-56-57890.
Examples include dispersants described in Japanese Patent Application Laid-open No. 56-57891 and the like. The ratio (weight ratio) of the dispersant of the present invention [and optionally the above (a), (b), (c) and/or (d)] to other dispersants is usually 10/90 to 100/
0 preferably 20/80 to 100/0 particularly preferably
The ratio is 50/50 to 100/0. The method for producing the coal-water slurry using the dispersant of the present invention may be any conventional method.
The water may be mixed in any order. For example, it can be prepared by dissolving or dispersing a dispersant in water, adding coal, and using a suitable mixing or grinding device. The viscosity of the coal-water slurry produced using the dispersant of the present invention has a coal concentration of 80% or more (80-95%).
%) water slurry is usually less than 5000 cp (at 20°C), especially 50 to 2000 cp. In addition, for example, a water slurry with a coal concentration of 60% usually has a value of less than 1000 cp (20
℃) especially 20 to 900 cp. Furthermore, coal concentration
Typically less than 2000cp (at 20℃) for 70% water slurry
Especially between 50 and 1400 cp. Further, the storage stability of these water slurries is usually 3 days or more, particularly 1 week or more. Coal referred to in the present invention includes anthracite coal, bituminous coal,
These include sub-bituminous coal and lignite. Coal particle size (particle size)
is usually 3 mm or less, preferably 1 mm or less, particularly preferably 0.5 mm or less. Coal-water slurries made using the dispersants of the present invention can be transported by conventional pipelines. The delivered coal-water slurry can be directly burned as fuel in a conventional pulverized coal boiler. It can also be used for various purposes such as gasification, liquefaction, and coke production. The coal-water slurry produced using the dispersant of the present invention can be prepared using conventional dispersants (e.g., JP-A-56
-21636 Publication, JP-A-56-20090, JP-A-Sho
Coal-water slurry produced using the dispersant described in JP-A No. 54-33803, JP-A-56-57889, JP-A-56-57890, JP-A-56-57891, etc. Compared to coal, the viscosity is extremely low (conventional coal concentration is 60%, coal average particle size is 0.074 mm, viscosity is 1200 cp or more, the present invention is 20 to 900 cp), and therefore the coal concentration can be increased to improve transportation efficiency (for example, concentration
70-95%) possible. In addition, when the coal concentration is relatively low (for example, 30% or more and less than 60%), a homogeneous coal-water slurry with extremely low viscosity can be obtained, and the energy required for transporting the coal and water slurry can be reduced. can. The present invention will be further explained below with reference to Examples, but the present invention is not limited thereto. In the following, EO, PO, and BO represent ethylene oxide, propylene oxide, and butylene oxide, respectively. Moreover, the ratio (fraction) indicates the weight ratio. However, O/C represents the oxygen/carbon atomic ratio in the polyoxyalkylene chain, and total O/C represents the oxygen/carbon atomic ratio in the total polyoxyalkylene chain in the dispersant molecule. MW indicates average molecular weight. Examples 1-2 and Comparative Examples 1-9 Dispersants of the present invention (Examples 1-2) and conventional dispersants (Comparative Examples 1-9) having the following compositions
A coal-water slurry was prepared using the method described below, and its performance was evaluated. Example 1 In formula (3), Y=pentaethylenehexamine residue,
l = 8, G = mixed polyoxyalkylene chain consisting of a 4/1 mixture of EO/PO, MW = 35000, total O/C = 0.463, EO% = 79.5% Example 2 Y = penta in formula (3) ethylene hexamine residue,
l = 8, -G-H: -Q-E-H, Q = polyoxypropylene chain, E = polyoxyethylene chain,
Q/E=1/4, MW=35000, total O/C=
0.463, EO%=79.5% Comparative Example 1 Formalin condensate of Naphthalene sulfonate, degree of condensation approximately 4. Comparative Example 2 Polyoxyethylene (approximately 100 mol) nonyl phenyl ether, MW: 4600. Comparative Example 3 Polyoxyethylene polypropylene glycol, MW approximately 3100, (polypropylene glycol
MW approx. 1750). Comparative Example 4 PO/EO block adduct of ethylenediamine,
MW approx. 2700, EO content: approx. 30%. Comparative Example 5 30 mole EO adduct of castor oil. Comparative example 6 EO20 of monolauric acid ester of sorbitan
molar adduct. Comparative Example 7 Na salt of copolymer of maleic anhydride/diisobutylene = 1/1, MW approximately 15,000. Comparative Example 8 Na salt of hydrolyzate of methyl methacrylate/styrene = 6/4 copolymer, MW, approximately 10,000. Comparative Example 9 Na salt of copolymer of acrylic acid/maleic acid = 1/1, MW approximately 6000. (1) Preparation of coal-water slurry and evaluation of fluidity Weigh out 1.75g of dispersant as an active ingredient (1.5g when coal concentration is 60% by weight) and add water to make a total of 150g (coal concentration of 60%). Dispersant is dissolved or dispersed in water (200g when the concentration is 60% by weight), and 350g of Minamidai Yubari No. 1 coal (when the coal concentration is 60% by weight) is crushed to 200 mesh and 80% pass in this aqueous solution (300g when the coal concentration is 60% by weight). was added little by little at room temperature.
After adding the entire amount, stir at 500 rpm for 5 minutes using a 6-blade radial blade turbine, then stir at 3000 rpm for 10 minutes using a homomixer (manufactured by Tokushu Kikako) to prepare a coal-water slurry, and heat to 20°C. The viscosity was measured and the fluidity was evaluated. The results are shown in Table 1. Low viscosity indicates good fluidity. (2) Evaluation of stability over time The test device used is a glass cylinder with an inner diameter of 5 cm and a height of 22 cm, the top of which can be sealed tightly. A certain amount of the coal-water slurry prepared as above was poured into this cylinder to a height of 15 cm from the bottom and allowed to stand at room temperature for one week. After one week, the cylinder was tilted and appearance, such as water separation, was evaluated. Hardness measurement is 3mm in diameter, 20g
Place the glass rod vertically on the surface of the slurry,
The time it took to penetrate the slurry layer under its own weight and reach the bottom was measured. The results are shown in Table 1. A product with little water separation, uniformity, and short rod penetration time indicates good stability over time. (3) Comprehensive evaluation Both fluidity and stability over time were evaluated. The results are shown in Table 1. This shows that those with good fluidity and good stability over time are overall superior. (Note)○*Minamidai Yubari No. 1 coal (Japanese bituminous coal, produced in Hokkaido) Calorific value 8390 (Kcal/Kg), inherent moisture 1.1%, ash content
5.1%, volatile content 36.2%, fixed carbon 57.6%, elemental analysis: C 62.8%, H 4.5%, O 4.7
%, N 1.2%. S 0.2%

【table】

[Table] From these results, the dispersant of the present invention has a sufficiently low viscosity even when the coal concentration is high (for example, 60% by weight or more), and even when stored for a long time (for example, one week), it does not require a large amount of water. It is clear that it has excellent effects such as maintaining good stability over time such as no separation and no coal aggregation.

Claims (1)

[Scope of Claims] 1. For use in coal slurry consisting of oil-free coal and water, characterized by containing a nonionic surfactant consisting of polyoxyalkylene ether of pentaethylenehexamine or higher polyalkylene polyamines. dispersant. 2. The dispersant according to claim 1, wherein the polyoxyalkylene ether is a co-adduct of ethylene oxide and an alkylene oxide having 3 or more carbon atoms. 3 The polyoxyalkylene ether is 5000~
The dispersant according to claim 1 or 2, having a molecular weight of 200,000. 4. A dispersant according to claim 1, 2 or 3, wherein the polyoxyalkylene ether contains at least 50% by weight of oxyethylene groups. 5. The dispersant according to any one of claims 1 to 4, wherein the polyoxyalkylene ether of the polyamine has a molecular weight of 5,000 to 100,000.