WO2015117869A1

WO2015117869A1 - Additives for coal water slurries

Info

Publication number: WO2015117869A1
Application number: PCT/EP2015/051654
Authority: WO
Inventors: Gledison Fonseca; Ann-Kathrin MARGUERRE
Original assignee: Basf Se
Priority date: 2014-02-07
Filing date: 2015-01-28
Publication date: 2015-08-13

Abstract

Mixture (A) containing from 10 to 60% by weight naphthalene sulfonic acid formaldehyde condensation products and from 90 to 40% by weight polyalkylene polyamines modified with acid groups. Mixture (B) containing from 95 to 99.9% by weight ground coal and from 5 to 0.1% by weight mixture (A). Aqueous mixture (C) containing from 20 to 60% by weight water and from 40 to 80% by weight mixture (B). Use of aqueous mixtures (C) for generating energy, for heating, for gasification of coal or for transporting coal in solution. Method for producing an aqueous mixture containing ground coal for burning, wherein the aqueous mixtures (C) are partially dewatered until a ground coal content of at least 50% by weight is achieved.

Description

Additives for coal-water slurries

The present invention relates to mixtures containing naphthalenesulfonic acid-formaldehyde condensation products and acid group-modified polyalkylenepolyamines, and the use and preparation of such mixtures. Another object of the invention are mixtures containing ground coal, containing naphthalenesulfonic acid-formaldehyde condensation products and modified with acid groups polyalkylenepolyamines, and the use and preparation of such mixtures. Likewise provided by the invention are aqueous mixtures which comprise water, ground coal containing naphthalenesulfonic acid-formaldehyde condensation products and acid group-modified polyalkylenepolyamines, and the use and preparation of such mixtures. The use of such aqueous mixtures for power generation, heating, gasification of coal or the transport of coal in solution are also the subject of the invention. Further embodiments of the present invention can be taken from the claims, the description and the examples. It is understood that the features mentioned above and those yet to be explained of the subject matter according to the invention can be used not only in the particular concretely specified combination but also in other combinations without departing from the scope of the invention. Preferred or very preferred are the embodiments of the present invention in which all features have the preferred or very preferred meanings.

Coal-water suspensions are used, for example, for the production of synthesis gas. Coal-water suspensions have the advantage during transport that they are pumpable compared to coal and can thus be transported through piping systems. For reasons of efficiency, it is necessary to keep the solids content of coal in the suspension as high as possible without, however, increasing the viscosity of the suspension to such an extent that the pumpability is lost. It is therefore known to use additives for the stabilization of coal-water suspensions.

JP 63-258 989 A discloses additives for stabilizing highly concentrated carbon-water suspensions comprising (a) condensation products of (alkyl) naphthalenesulfonic acids and formaldehyde, and (b) an amide of a fatty acid and a polyethylene polyamine. The ratio of the components (a) to (b) is preferably 50/50 to 98/2. The polyethylenepolyamine is preferably an amine of the formula H 2 N- (CH 2 CH 2 NH) _n -H, where n is a number from 2 to 15.

JP 64-065191 A discloses additives for stabilizing highly concentrated carbon-water suspensions comprising (a) 40 to 90% by weight of condensation products of (alkyl) naphthalenesulfonic acids and formaldehyde, (b) 5 to 30% by weight of a C6-bis C22 fatty acid; and (c) 5 to 30% by weight of an alkoxylated amide of a fatty acid and a polyethylene polyamine. The polyethylene polyamine has the general formula H2N- (CH 2 CH 2 lMH) _n -H, where n is a Number from 2 to 15 stands. The alkoxylation of the amide is preferably carried out with 1 to 5 moles of ethylene oxide and / or propylene oxide per active H atom of the amide.

JP 01 -092284 A discloses additives for stabilizing highly concentrated carbon-water suspensions comprising (a) condensation products of (alkyl) naphthalenesulfonic acids and formaldehyde having an average degree of condensation of 10 to 500 and (b) alkoxylated polyalkyleneimines obtainable by reacting polyalkyleneimines comprising 7 to 200 nitrogen atoms and 0.25 to 1 mole of α-olefin epoxides having 8 to 30 carbon atoms per active H atom and 30 to 200 moles of ethylene oxide per active H atom. The ratio of (a) to (b) is preferably 8: 2 to 9.5: 0.5. The high proportion of formaldehyde condensation products compared to the alkoxylated polyalkyleneimines is necessary according to JP 01 -092284 A in order to avoid gelation.

EP 0124670 A1 describes stable carbon-water suspensions with low viscosity containing finely divided carbon particles, ammonium salts of organic dispersants and alkaline earth metal salts of organic dispersants.

No. 4,498,906 describes stable coal-water suspensions containing finely divided carbon particles, alkali metal salts of organic dispersants and alkaline earth metal salts of organic dispersants.

EP 0 171 602 A2 describes aqueous, flowable carbon dispersions with a nonionic dispersant. The nonionic dispersant is an alkoxylation product of dihydroxydiphenyldimethylmethane.

WO 2005/073357 A2 discloses polymers for the treatment of hard surfaces such as the surfaces of glass, ceramic, metal, stainless steel, enamel, painted surfaces or plastic. To treat the hard surfaces are modified with acid groups modified polyethyleneimines, which may additionally also be slightly crosslinked. The use of such polymers to stabilize coal-water dispersions is not disclosed.

The prior art processes allow coal-water suspensions to be produced, stored and transported. However, there is still a need for improved additive systems for producing carbon-water suspensions, particularly those that result in lower viscosities of coal-water slurries.

It was therefore an object of the present invention to provide further carbon-water suspensions which nevertheless have a low viscosity despite a high solids content. Another object of the present invention was to provide aqueous coal-water suspensions which facilitate the removal of excess water prior to use as a fuel suspension. Accordingly, mixtures (A) containing

(A-a.) Of 10 to 50 wt .-%, preferably from 20 to 50 wt .-%, particularly preferably from 25 to 45 wt .-% of naphthalenesulfonic acid-formaldehyde condensation products and

(Ab.) From 90 to 50 wt .-%, preferably from 80 to 50 wt .-%, particularly preferably from 75 to 65 wt .-% acid group-modified polyalkylenepolyamines found, wherein the amounts given in each case to the total amount of the components ( Aa.) And (Ab.) Are related.

The mixtures (A) are used according to the invention for the stabilization of coal-water slurries.

Specifically, the following is to be carried out for the invention: Naphthalenesulfonic acid-formaldehyde condensation products (A-a.) Naphthalenesulfonic acid-formaldehyde condensation products (A-a.) Are known in principle to a person skilled in the art and comprise one or more condensation products of one or more naphthalenesulfonic acids or derivatives thereof. Derivatives may, for example, be salts. Of course, mixtures of two or more naphthalenesulfonic acid-formaldehyde condensation products can be used. The sulfonic acid groups in the condensate may be in the form of acid groups or may preferably be completely or partially neutralized. For example, they may be present as sodium salts.

Naphthalenesulfonic acid-formaldehyde condensation products can be prepared by processes known to those skilled in the art, as described, inter alia, in DE 199 54 013 A1 or WO 98/03577 A1. Naphthalenesulfonic acid-formaldehyde condensation products are also commercially available (for example as Tamol ^® from. BASF SE).

In one embodiment of the mixture (A) according to the invention, the naphthalenesulfonic acid-formaldehyde condensation products used have a molecular weight M _w (weight average) of from 1000 to 10000 g / mol, preferably from 5000 to 8000 g / mol and more preferably from 6000 to 7000 g / mol. The determination of the molecular weight distribution of naphthalene sulphonic acid condensates is carried out relative to polystyrene sulfonates (Na salts) by aqueous GPC to PSS HEMA BIO ^® -Gelsäulen (cross-linked hydroxyethyl methacrylate). In a further embodiment of the mixture (A) according to the invention, the naphthalenesulfonic acid-formaldehyde condensation products used have a molecular weight M _n (number lenmittel) of 500 to 5000 g / mol, preferably from 500 to 3000 g / mol and particularly preferably from 700 to 2000 g / mol.

The naphthalenesulfonic acid-formaldehyde condensation products used generally have a polydispersity index (M _w / M _n ) of from 2 to 20, preferably from 3 to 10 and particularly preferably from 4 to 8.

The said naphthalenesulfonic acid-formaldehyde condensation products used may also comprise the remainder of the naphthalenesulfonic acids used as starting materials, for example naphthalene-1-sulfonic acid, naphthalene-2-sulfonic acid or naphthalenedisulfonic acids, or in each case salts thereof, in particular Na salts.

The naphthalenesulfonic acid-formaldehyde condensation products to be used should preferably comprise not less than 75% by weight of condensates and not more than 25% by weight of unreacted naphthalenesulfonic acids or salts thereof, the figures indicating the total amount of condensates and remaining Refers to starting materials.

In one embodiment of the invention, a naphthalenesulfonic acid-formaldehyde condensation product can be used, which in addition to the condensates

Naphthalene-1-sulfonic acid, or salts thereof, in particular from 0.1 to 5% by weight, preferably from 0.2 to 3% by weight,

Naphthalene-2-sulfonic acid, or salts thereof, in particular 5 to 20 wt .-%, preferably 5 to 15 wt .-%, and

Naphthalenedisulfonic acids, or salts thereof, in particular 5 to 20 wt .-%, preferably 5 to 10 wt .-%, wherein the amounts are based on the total amount of condensate and naphthalene-1-sulfonic acid, naphthalene-2-sulfonic acid and naphthalenedisulfonic acids.

Acid group-modified polyalkylenepolyamines (A-b.)

As component (A-b.) Of the mixture (A) according to the invention, polyalkylenepolyamines modified with acid groups are used. These are obtainable by reacting polyalkylenepolyamines with suitable acid group-containing reagents.

Polyalkylenepolyamines to be used as starting material for the modifications comprise at least two alkylene groups, for example C ₂ - to C ₄ -alkylene groups, and also primary, secondary and / or tertiary amino groups, where at least one secondary and / or tertiary amino group is present. In a preferred embodiment of the invention, the polyalkylene polyamines are polyalkyleneimines. Polyalkyleneimines, such as, for example, polyethylenimine or polypropylenimine, are known to the person skilled in the art and can be prepared by processes known to the person skilled in the art. Polyethyleneimines and polypropyleneimines are commercially available (for example BASF SE as Lupasol®, Sokalan® HP20).

In a preferred embodiment of the mixture (A) according to the invention, the acid group-modified polyalkylenepolyamine is a polyethylenimine or polypropylenimine modified with acid groups. Most preferably, the modified polyalkylenepolyamine is an acid group-modified polyethylenimine.

Modified polyalkylenepolyamines according to the present application are understood as meaning, for example, modified polyethylenimines, polypropyleneimines, polybutylenimines and higher homologs. The modified polyalkylenepolyamines, preferably polyethyleneimines or polypropyleneimines, in particular polyethyleneimines, preferably have an average molecular weight (weight average M _w ) of at least 300. The average molecular weight of the polyethyleneimines is preferably from 800 to 2,000,000, more preferably 20,000 to 1,000,000, most preferably 20,000 to 75,000 , determined by means of light scattering. The molecular weight distributions are determined by size exclusion chromatography (SEC). The calibration is carried out using narrowly distributed poly (2-vinylpyridine) standards from PSS, Germany, with molecular weights of M = 839 to M = 2.070,000.

Acid group-modified polyalkylenepolyamines are obtained by chemical modification of polyalkylenepolyamines, preferably of polyalkylenimines, and indeed in the case of the acid-group-modified polyalkylenepolyamines, the hydrogen atoms on the N-atoms of the polyalkylenepolyamines are wholly or partially substituted by substituents of general formula R ¹ -AM (I) where A is an acid group, M is H or a cation, in particular an alkali metal or ammonium ion, and R ^{1 is} a linking group, in particular a C ¹ - to C ₄ -alkylene group, in particular a methylene group --CH 2 - or ethylene group - CH2CH2-. The acid groups may, in particular, be carboxyl groups -COOH, sulfonic acid groups -SO 3 H or phosphonic acid groups -PO (OH) 2 or salts thereof. Preference is given to COOH groups or salts thereof. Examples of preferred substituents -R ¹ -AM include -CH ₂ COOH and -CH ₂ CH ₂ COOH or salts thereof.

For modification, the polyalkylenepolyamines can be reacted with suitable reagents containing acid groups, with the above-described substitution of the H atoms on the N atoms taking place. Preferred unmodified polyalkylenepolyamines used as the starting material include polyethyleneimine having a weight-average molecular weight M _w of 5,000 to 50,000 g / mol, preferably 10,000 to 30,000 g / mol. Suitable reagents for modifying the polyalkylenepolyamines include, in particular, monoethylenically unsaturated carboxylic acids which preferably have 3 to 18 carbon atoms in the alkenyl radical. Examples of suitable monoethylenically unsaturated carboxylic acids include Acrylic acid, methacrylic acid, dimethacrylic acid, ethylacrylic acid, allylacetic acid, vinylacetic acid, maleic acid, fumaric acid, ethaconic acid, methylenemalonic acid, citraconic acid, oleic acid and linolenic acid. The monoethylenically unsaturated carboxylic acids are preferably selected from the group consisting of acrylic acid, methacrylic acid and maleic acid. Such monoethylenically unsaturated carboxylic acids can be added to the polyalkylenepolyamines in a Michael addition.

Furthermore, the salts of the abovementioned monoethylenically unsaturated carboxylic acids are suitable. Suitable salts are generally the alkali metal, alkaline earth metal and ammonium salts of the abovementioned acids. Preferred are the sodium, potassium and ammonium salts. The ammonium salts can be derived from both ammonia and amines or amine derivatives such as ethanolamine, diethanolamine and triethanolamine. Suitable alkaline earth metal salts are generally magnesium and calcium salts of the abovementioned monoethylenically unsaturated carboxylic acids.

Further examples include monoethylenically unsaturated sulfonic acids of the following formulas

H ₂ C = CH-X-SO ₃ H (II)

H ₂ C = C (CH ₃ ) -X-SO ₃ H (III) where X is either absent or a spacer group of the formulas -C (O) -NH-CH ₂ -n (CH ₃ ) n (CH ₂ ) m, -C (O) NH-, -C (O) -NH- (CH (CH ₃ ) CH ₂ -, or -C (O) -NH-CH (CH ₂ CH ₃ ) -, wherein n 0 to 2 and m is 0 to 3. Particularly preferred are 1-acrylamido-1-propanesulfonic acid (X = -C (O) -NH-CH (CH ₂ CH ₃ ) - in formula II), 2-acrylamido-1 propanesulfonic acid (X = -C (O) -NH-CH (CH ₃ ) CH ₂ - in formula II), 2-acrylamido-2-methyl-1-propanesulfonic acid (X = -C (O) -NH-C ( CH ₃ ) ₂ CH ₂ -) - in formula II), 2-methacrylamido-2-methyl-1-propanesulfonic acid (X = -C (O) -NH-C (CH ₃ ) ₂ CH ₂ -) - in formula III ) and vinylsulfonic acid (X not present in formula II). An example of a reagent comprising phosphonic acid groups includes vinylphosphonic acid.

Further examples of suitable reagents include halocarboxylic acids, especially chlorocarboxylic acids. Suitable chlorocarboxylic acids are, for example, chloroacetic acid, 2-chloropropionic acid, 2-chlorobutyric acid, dichloroacetic acid and 2,2'-dichloropropionic acid.

Further examples of suitable reagents include glycidylic acid (IV)

or salts thereof, for example Na, K or ammonium salts. The preferred reagent used is a monoethylenically unsaturated carboxylic acid, particularly preferably acrylic acid, methacrylic acid or maleic acid, very particularly preferably acrylic acid. The acid group-modified polyalkylenepolyamines can optionally be crosslinked. This can be done before or after the modification with acid groups, preferably before the modification with acid groups. The degree of crosslinking is so limited by the expert that the solubility of the acid group-modified polyalkylenepolyamines in water is not impaired.

Examples of suitable crosslinkers include at least difunctional compounds having as functional groups a halohydrin, glycidyl, aziridine or isocyanate moiety or a halogen atom. Suitable crosslinkers are, for example, epihalohydrins, preferably epichlorohydrin, and also a, co-bis (chlorohydrin) polyalkylene glycol ethers and the a, co-bis (epoxides) of polyalkylene glycol ethers obtainable therefrom by treatment with bases. The chlorohydrin ethers are prepared, for example, by reacting polyalkylene glycols in the molar ratio 1 to at least 2 to 5 with epichlorohydrin. Suitable polyalkylene glycols are, for example, polyethylene glycol, polypropylene glycol and polybutylene glycols and block copolymers of C 2 -C ₄ -

Alkylene oxides. The average molecular weights (M _n ) of the polyalkylene glycols are generally from 200 to 6000, preferably from 300 to 2000 g / mol. a, co-bis (chlorohydrin) polyalkylene glycol ethers are described, for example, in US 4,144,123. As also disclosed therein, the corresponding bisglycidyl ethers of the polyalkylene glycols are formed from the di-chlorohydrin ethers by treatment with bases.

Further suitable crosslinkers are α, ω-dichloropolyalkylene glycols, as disclosed, for example, in EP-A 0 025 515. These α, ω-dichloropolyalkylene glycols are obtainable by reacting dihydric to tetrahydric alcohols, preferably alkoxylated dihydric to tetrahydric alcohols, either with thionyl chloride with elimination of HCl and subsequent catalytic decomposition of the chlorosulfonated compounds with elimination of sulfur dioxide, or with phosgene with elimination of HCl converted into the corresponding Bischcorkohlensäureester and then obtained by catalytic decomposition with carbon dioxide cleavage α, ω-dichloro.

The dihydric to tetrahydric alcohols are preferably ethoxylated and / or propoxylated glycols which are reacted with from 1 to 100, in particular from 4 to 40, mol of ethylene oxide per mole of glycol. Further suitable crosslinkers are α, ω or vicinal dichloroalkanes, for example 1, 2

Dichloroethane, 1, 2-dichloropropane, 1, 3-dichloropropane, 1, 4-dichlorobutane and 1, 6-dichlorohexane. Further suitable crosslinkers are the reaction products of at least trivalent alcohol bring with epichlorohydrin to reaction products which have at least two chlorohydrin units. For example, glycerol, ethoxylated or propoxylated glycerols, polyglycerols having 2 to 15 glycerol units in the molecule and optionally ethoxylated and / or propoxylated polyglycerols are used as the polyhydric alcohols. Crosslinking agents of this type are known, for example, from DE-A 29 16 356. Further suitable are crosslinkers containing blocked isocyanate groups, for example trimethylhexamethylene diisocyanate blocked with 2,2,3,6-tetramethylpiperidinone-4. These crosslinkers are known, for example, from DE-A 40 28 285. Further, aziridine-containing crosslinking agents based on polyethers or substituted hydrocarbons, for example, 1, 6-bis-N-aziridinohexane suitable. According to the present application, the crosslinkers can be used individually or as mixtures of two or more crosslinkers.

Epihalohydrins, preferably epichlorohydrin, .alpha.,. Omega.-bis (chlorohydrin) polyalkylene glycol ethers, a, co-bis (epoxides) of the polyalkylene glycol ethers and / or bisglycidyl ethers of the polyalkylene glycols are preferably used as crosslinkers. Examples of preferred α, ω-bis-

(Chlorohydrin) polyalkylene glycol ethers include a, co-bis (chlorohydrin) polyethylene glycol ethers having an average molar mass M _n of 300 to 3000 g / mol, preferably 500 to 2000 g / mol.

In one embodiment of the invention, it is possible to use as component (Ab) acid groups modified polyalkyleneamines which by crosslinking of polyethyleneimine, preferably polyethyleneimine having a weight-average molecular weight M _w of 5000 to 50,000 g / mol, preferably 10000 g / mol to 30,000 g / mol with a, o bis-

(Chlorohydrin) polyethylene glycol ethers having an average molar mass M _n of 300 to 3000 g / mol, preferably 500 to 2000 g / mol, followed by reaction with acrylic acid are available.

The preparation of such, with acid groups modified, optionally crosslinked polyalkylenepoly- amine is described in WO 2005/073357 (pages 14 to 15 and Preparation Examples 1 to 5 on pages 22 to 25).

Mixtures (A)

According to the invention, the mixtures (A) are prepared by mixing naphthalenesulfonic acid-formaldehyde condensation products and acid groups-modified polyalkylene polyamines (A-b.). The components (A-a.) And (A-b.) Are mixed together in the following proportions

(A-a.) Of 10 to 50 wt .-%, preferably from 20 to 50 wt .-%, particularly preferably from 25 to 45 wt.% And

(Ab.) Of 90 to 50 wt .-%, preferably from 80 to 50 wt .-%, particularly preferably from 75 to 65 wt.%, wherein the quantities are based on the total amount of components (Aa.) And (Ab.).

Such mixtures can also be prepared as aqueous mixtures using water, preferably distilled water. The concentration of components (A-a.) And (A-b.) In water will be determined by those skilled in the art according to the desired properties and intended use. It may for example be 1 wt .-% to 40 wt .-% amount.

The mixtures (A) can be used according to the invention for the stabilization of coal-water slurries. They are mixed for this purpose with a coal and water using suitable mixing equipment.

Mixtures (B)

Another object of the invention is therefore the inventive mixture (B) containing

(B-a.) Of 95 to 99.9 wt .-%, preferably from 97 to 99.8 wt .-%, particularly preferably from 98 to 99.5 wt .-% of ground coal, and

(Bb.) Of 5 to 0.1 wt .-%, preferably from 3 to 0.2 wt .-%, particularly preferably from 2 to 0.5 wt .-% of the mixture (A) according to the invention, wherein the quantities in % By weight based on the total amount of ground coal (component Ba.) And mixture (A) (component Bb.).

Ground coal is prepared by methods known to those skilled in the art, which are described for example in EP124670A1, US 4,498,906 or JP 01 -092284 A.

The composition of coal can vary over a wide range. In general, coal contains: carbon (45-90% by weight), oxygen (10-30% by weight), moisture (5-40% by weight) with an ash content of 3-20%. The milled coal is preferably finely divided, particularly preferably having a particle size distribution which is suitable for transport and combustion, very particularly preferably having a particle size distribution at which 100% of the particles have a particle diameter of less than 100 μm and 50% of the particles have a particle diameter of have less than 70 μηη.

The particle size distribution of coal can be influenced by grinding. Often one strives for reasons of the highest possible solids content by grinding bi- or to obtain multimodal distributions. For example, bimodal distributions of 80 to 50% by volume have larger particles with a particle size of 100 to 70 μm and from 20 to 50% by volume smaller particles of 70 to 20 μm in particle diameter. According to the invention, the mixtures (B) are prepared by mixing ground coal (Ba.) And the mixture (A) (Bb.) According to the invention. The components (Ba.) And (Bb.) Are mixed together in the following proportions

(B-a.) Of 95 to 99.9 wt .-%, preferably from 97 to 99.8 wt.%, Particularly preferably from 98 to 99.5 wt .-% and

(Bb.) Of 5 to 0.1 wt .-%, preferably from 3 to 0.2 wt.%, Particularly preferably from 2 to 0.5 wt .-%, wherein the amounts are in wt .-% based on the total amount of ground coal (component Ba.) and mixture (A) (component Bb.).

Such mixtures can also be prepared as aqueous mixtures using water, preferably distilled water.

Another object of the invention is the use of mixtures (A) according to the invention for the preparation of mixtures (B) according to the invention.

Mixture (C)

Another object of the invention is the inventive aqueous mixture (C) containing (C-a.) Of 20 to 60 wt .-%, preferably from 25 to 50 wt.%, Particularly preferably from

From 30 to 40% by weight of water and

(Cb.) Of 40 to 80 wt .-%, preferably from 50 to 75 wt.%, Particularly preferably from 60 to 70 wt .-% mixture (B), wherein the amounts in wt .-% based on the total amount of water (component Ca.) and mixture (B) (component Cb.).

According to the invention, the mixtures (C) are prepared by mixing water (Ca.) and mixture (B) (Cb.) According to the invention. The components (Ca.) and (Cb.) are mixed together in the following proportions (Ca.) from 20 to 60 wt .-%, preferably from 25 to 50 wt.%, Particularly preferably from 30 to 40 wt .-% water, and

(Cb.) Of 40 to 80 wt .-%, preferably from 50 to 75 wt.%, Particularly preferably from 60 to 70 wt .-% of the mixture according to the invention (B) wherein the amounts are in wt .-% based on the total amount of water (component Ca.) and mixture (B) (component Cb.). Another object of the invention is the use of mixtures (B) according to the invention for the preparation of mixtures (C) according to the invention.

Use of the mixtures (C)

Another object of the invention is the use of aqueous mixtures (C) for energy production, for heating, the gasification of coal or the transport of coal in solution. Another object of the invention is a process for the preparation of an aqueous mixture containing ground coal for combustion, characterized in that aqueous mixtures (C) are partially dehydrated according to a content of ground coal of at least 50 wt .-% is reached. Preference is given to contents of at least 60% by weight, more preferably from 60 to 80% by weight, in particular from 60 to 75% by weight.

The present invention provides coal-water suspensions as mixture (C) which have low viscosities despite a high solids content. Furthermore, aqueous carbon-water suspensions are provided as mixture (C), which are easy to handle when used as a fuel suspension.

The invention is explained in more detail by the examples, without the examples limiting the subject matter of the invention.

Examples:

Used naphthalenesulfonic acid-formaldehyde condensation products and polyalkyleneamines used:

Component Description

K 1 Commercially available naphthalenesulfonic acid-formaldehyde condensation product, Na salt, M _n about 1000 g / mol, M _w 6000 -. 7000 g / mol (content about 75% by weight condensation product, naphthalene-1-sulfonic acid ca. 2% by weight, naphthalene-2-sulfonic acid about 14% by weight, naphthalenedisulfonic acid about 9% by weight)

PA 1, partially cross-linked polyethyleneimine modified with COOH groups, comprises> N-CH ₂ CH ₂ COOI-1 groups, preparation according to WO 2005/073357 A2, Example 3:

In a four-necked flask with metal stirrer and reflux condenser 350 g of polyethyleneamine (56% strength, Mw = 25,000 g / mol, Luupasol® HF) are added under nitrogen atmosphere and diluted with 456 g deionized water. It is heated with stirring to 70 ° C and at this temperature, 18 ml of a 50 g of aqueous solution of a crosslinking agent are added rapidly. The crosslinker is a reaction product of a medium molecular weight polyethylene glycol 660 with epichlorohydrin. After completion of the addition, the mixture is stirred for 5 hours at 70 ° C. Subsequently, the reaction solution is heated to 80 ° C and treated dropwise at this temperature within 3 hours with 259.4 g of acrylic acid. After completion of the addition, the solution is stirred at 95 ° C for an additional hour. After cooling, a viscous, yellow-orange solution of the product with a solids content of 44.1% (2 h, vacuum / 120 ° C) and a K value (1% in water) of 23.1. For the tests, a solution of the product with a solids content of 40% by weight was used.

PA 2 branched polyethylenimine (unmodified), M _n about 800 g / mol

(Comparison)

PA 3 branched polyethylenimine (unmodified), M _n about 5000 g / mol

(Comparison) Coals used for testing (particle size <70 μηη):

Carbon. 64.3g / 100g

Oxygen 24.6 g / 100g

Sulfur 0.57 g / 100g

Nitrogen 1 .1 g / 100g

Hydrogen. 5.0g / 100g

ASH 9.6 g / 100g

Execution of the tests:

To carry out the tests, first mixtures of K1 and PA 1 or K1 and PA 2 or K1 and PA 3 were prepared in water at different ratios of the components. The mixing ratios are given in Table 1, respectively. For comparison purposes, mixtures of K1 were respectively. only used by PA 1 in water. The total solids content of the aqueous mixtures was in each case 30% by weight. In each case 1 g (containing 0.3 g of solid) of the said aqueous mixtures were dissolved in 19.0 g of distilled water. With stirring (32 mm dispersing disk, 1500 rpm), in each case 30 g of carbon powder (particle size <70 μm) were drizzled in. The amount of the polymers with respect to coal is consequently 1% by weight For comparison purposes, a sample was furthermore prepared only with water.

After stirring for 10 minutes, 50 ml of the dispersion were transferred to a snap-cap glass and the viscosity was determined (plate / plate measurement with Anton Paar MCR 301 and spindle measurement with Brookfield viscometer). The results of the viscosity measurements are given in Table 1.

In the zero test without the addition of polymers (comparative experiment V1), a viscosity of 300 mPas was measured. If one uses only the condensation product K 1 (Comparative Experiment V2), the viscosity of the water-carbon dispersion drops only slightly to 260 mPas. If one uses only the modified polyethyleneimine PA 1 (Comparative Experiment V5), then the viscosity remains unchanged.

If, on the other hand, mixtures of the modified polyethyleneimine PA 1 and the formaldehyde naphthalenesulfonic acid product K1 are used, the viscosity of the water / carbon dispersion changes at a concentration of the modified polyethyleneimine PA 1 of 20% by weight or 40% by weight. -% barely. At a level of 60% by weight and 80% by weight, on the other hand, a marked drop in viscosity to 130 mPas is observed. Mixtures of formaldehyde naphthalene sulfonic acid product K1 and acid group-modified polyethyleneimines thus show very good results with high amounts of the modified polyethyleneimine. This is extremely advantageous because the modified polyethylenimine is the cheaper of the two polymeric products.

Comparative experiments V 6 to V1 1 with unmodified polyethyleneimines show that the viscosity of the carbon-water dispersion increases independently of the mixing ratio compared to a sample without addition of polymer.

1: Results of Examples and Comparative Examples with Coal 1

Claims

claims:

Containing mixture (A)

(A-a.) From 10 to 50 wt .-% naphthalenesulfonic acid-formaldehyde condensation products and

(A-b.) From 90 to 50 wt .-% modified with acid groups polyalkylenepolyamines, wherein the amounts are in each case based on the total amount of the components (A-a.) And (A-b.).

Mixture according to claim 1, wherein the naphthalenesulfonic acid-formaldehyde condensation product has a molecular weight M _w of 1000 to 10000 g / mol.

Mixture according to claim 1 or 2, wherein the naphthalenesulfonic acid-formaldehyde condensation product has a molecular weight M _n of 100 to 5000 g / mol.

Mixture according to claims 1 to 3, wherein the naphthalenesulfonic acid-formaldehyde condensation product has a polydispersity index (M _w / M _n ) of 2 to 20.

Mixture according to claims 1 to 4, wherein the naphthalenesulfonic acid-formaldehyde condensation product (A-a.) In addition to the condensation product as further components naphthalene-1-sulfonic acid, naphthalene-2-sulfonic acid and naphthalenedisulfonic acids.

Mixture according to Claims 1 to 5, wherein in the acid group-modified polyalkylenepolyamine, the H atoms on the N atoms of the polyalkylenepolyamines are wholly or partially substituted by substituents of the general formula -R ¹ -AM (I), where A is an acid group is selected from the group of carboxyl groups, sulfonic acid groups or phosphonic acid groups, M is H or a cation, in particular an alkali metal or ammonium ion, and R ^{1 is} a C ¹ -C ₄ -alkylene group.

Mixture according to claim 6, characterized in that -R ¹ -AM is a -CH 2 -COOH or -CH 2 CH 2 -COOH group or salts thereof.

The blend of claims 1-7 wherein the acid group-modified polyalkylene polyamine is an acid group-modified polyethyleneimine or polypropyleneimine.

Mixture according to claims 1 to 8, wherein the polyalkylenepolyamine is crosslinked.

10. Mixture according to claim 9, wherein the crosslinking by means of a crosslinker selected from the group of epichlorohydrin, a, co-bis (chlorohydrin) polyalkylene glycol ethers, a, co-bis (epoxides) of the polyalkylene glycol ethers and / or bisglycidyl ethers of the polyalkylene glycols performs.

1 1. Mixture according to Claims 1 to 5, wherein the acid group-modified polyalkylene polyamine (Ab.) Is prepared by crosslinking polyethyleneimine having a weight-average molecular weight M _{w of} from 10,000 g / mol to 30,000 g / mol with α, ω-bis (chlorohydrin) polyethylene glycol ether having an average molar mass M _n of 500 to 2000 g / mol, followed by reaction with acrylic acid.

12. containing mixture (B)

(B-a.) From 95 to 99.9 weight percent ground coal, and

(Bb.) From 5 to 0.1 wt .-% mixture (A) according to claims 1 to 7 wherein the amounts in wt .-% based on the total amount of ground coal (component Ba.) And mixture (A) (Component Bb.).

A blend according to claim 8 wherein the ground coal is finely divided.

14. Aqueous mixture (C) containing (C-a.) From 20 to 60 wt .-% water and

(Cb.) From 40 to 80 wt .-% mixture (B) according to claims 12 to 13 wherein the amounts in wt .-% based on the total amount of water (component Ca.) and mixture (B) (component Cb .).

15. Use of mixtures (A) according to claims 1 to 1 1 for the preparation of mixtures (B) according to claims 12 to 13. 16. Use of mixtures (B) according to claims 12 to 13 for the preparation of aqueous mixtures ( C) according to claim 14.

17. Use of aqueous mixtures (C) according to claim 16 for the production of energy, for heating, the gasification of coal or the transport of coal in solution.

18. A process for preparing an aqueous mixture containing ground coal for combustion, characterized in that aqueous mixtures (C) are partially dehydrated according to claim 14, until a content of ground coal of at least 50 wt .-% is reached.