JPH0316997B2 - - Google Patents

Abstract

Coal-aqueous mixture having high solids content and excellent stability are provided by an improved process involving selective mixing and other conditions.

Description

[Detailed description of the invention]

FIELD OF THE INVENTION This invention relates to carbonaceous materials, and in particular to coal-water mixtures. Coal is in abundant supply as an energy source. It is estimated that there is more energy in the United States from coal than from oil, natural gas, oil shale, and tar sands. Therefore, replacing natural gas and oil with coal on a large scale seems to be a promising solution to energy problems. Unfortunately, unlike oil and gas, coal is not determined by stockpiles or production capacity, but rather by industrial and regulatory requirements to burn it in convenient, efficient, and environmentally acceptable ways. The fact is that its use is restricted because it is so difficult that it can be called abnormal. Many technologies have been developed to provide coal as a more efficient energy source. One is that gasification methods such as cracking distillation can produce coal with low or medium Btu.
This is a technology that converts it into gas. There is also a method of liquefying coal by high-pressure hydrogenation to make it easier to transport and burn. Furthermore, to which the present invention relates, techniques have also been proposed in which solid coal particles are dispersed in a fluid carrier medium such as fuel oil or water to form a coal-water or coal-oil mixture. However, coal-oil and coal-water mixtures are unique systems, each presenting unique difficulties in their preparation. For example, coal and oil are relatively compatible, but coal and water are not. Therefore, unlike the preparation of coal-oil mixtures, in the preparation of coal-aqueous mixtures, the initial dispersion of coal into the continuous phase of water, especially the dispersion of large amounts of coal, is a major challenge. Stabilization after dispersion, that is, prevention of separation of coal from the aqueous phase, is also a difficult problem. Such a coal mixture has many advantages.
These are easier to transport than dry solid coal, easier to store, and have less risk of explosion due to instantaneous combustion, and the latter is particularly important in handling coal. In addition, the supply of coal in fluid form allows the use of equipment normally used for combustion of liquid fuels. This is highly desirable as it greatly facilitates the conversion of fuel oil to coal as the main energy source. Various coal-oil and coal-water mixtures are described in the literature. For example, British Patent No. 1,523,193 discloses a mixture of fuel oil and 15-55% by weight of highly ground coal particles having a particle size of less than 10 microns. However, the effort required to grind the coal so finely makes this process economically unattractive. The use of fuel oil as a carrier medium also runs counter to the desire to reduce dependence on fuel oil. U.S. Pat. No. 4,251,229 discloses examples of coal-oil mixtures stabilized with high molecular weight adducts of alkylene oxides and alcohols, amines, carboxylic acids or phenols (having at least three active hydrogens). In this US patent, oil is the continuous medium phase and the stabilization of the coal in this continuous oil phase is the only concern. No. 4,242,098 discloses an aqueous coal slurry composition containing a water-soluble polymer as a thickening agent, such as xanthan gum, hydroxypropyl agar gum, or poly(ethylene oxide) having a molecular weight of 100,000 or more. U.S. Pat. No. 3,762,887 discloses dispersing coal that has been ground to a specific particle size (mostly about a 325 mesh Tyler standard screen or more finely ground) in an aqueous medium. Here the coal must be selectively crushed. US Pat. No. 4,217,109 discloses a technique for dispersing and washing coal in water using a dispersant that selectively adsorbs carbon particles and impurities by imparting different charges to them. Dispersants disclosed are polyelectrolytes such as alkali metal and ammonium salts of polycarboxylic acids and polyphosphoric acids. Deuelopment and Evaluation of Highly Published at the Second International Symposium on Combustion of Coal-Oil Mixtures, November 27-29, 1979.
The paper entitled ``Loadod Coal Slurries'' uses coal with a bimodal particle size distribution and uses modified starches, biocides and moisturizers such as TRITONX, a low molecular weight octylphenoxy (ethyleneoxy) ethanol surfactant. Coal-water-based mixtures containing agents are disclosed. According to US Pat. No. 3,617,095, the preparation of emulsions by mixing a solid such as coal with water and alcohol in the presence of an oxyalkylated octylphenol emulsifier is described in that document. Finally, many other patents disclose mechanical treatments and dispersants to provide coal in a carrier medium. For example, US Patent 4088453;
4104035; 3620698; 3764547; 3996026;
See European Patent No. 0050412 and PCT International Publishing WO81-01152. Although these prior art attempts have been made to provide coal in dispersed fluid form, improvements to these methods are still needed to provide coal mixtures without excessive mechanical or chemical treatments. . coal
It would be highly desirable to be able to provide coal in the form of an aqueous mixture by adding small amounts of additives to disperse it to high solids concentrations of 70% by weight or more. It would be even more preferable to provide a coal-aqueous mixture that has been cleaned of impurities in the coal, thereby achieving clean combustion and environmental acceptance. U.S. Pat. No. 4,358,293, dated Nov. 9, 1952, discloses the discovery that certain polyalkylene oxide nonionic surfactants are excellent additives for forming coal-water mixtures with high coal solids concentrations. There is also a polyalkylene oxide nonionic surfactant having a hydrophobic portion and a hydrophilic portion, the hydrophilic portion having at least about 100 ethylene oxide repeat units, which is used to disperse granular coal in water. When present in sufficient quantities, coal concentration is approximately 70% by weight
It has been disclosed to provide coal-water dispersions with very high coal solids concentrations of 50% or more.
The resulting mixture has amphiphilic properties and can provide coal in a form that can be transported, stored, and burnt cleanly. Surprisingly, the surfactant used can vary in chemical structure as long as it is of the type selected, has sufficient molecular weight, and has at least about 100 ethylene oxides. Even more surprisingly, the above-mentioned U.S. patent
In the preparation of the coal-water slurry disclosed in No. 4,358,293, it has been found that a significantly improved coal-water slurry is obtained by using certain operating conditions detailed below. For example, the coal slurry obtained according to the invention is characterized by a high solids content, an extremely long storage stability and other advantages mentioned below. The present invention (i) mixes a polyalkylene oxide nonionic surfactant having a hydrophobic part and a hydrophilic part, the hydrophilic part having at least 100 units of ethylene oxide with water under low speed stirring conditions; (ii) A coal-aqueous mixture characterized in that granular coal is mixed with the mixture obtained in step (i) under medium speed stirring, and (iii) the coal-containing mixture obtained in step (iii) is stirred under high speed stirring. Regarding the forming method. The present invention also includes granular coal as the dispersed solid material, water as the carrier medium, and a polyalkylene oxide nonionic surfactant having a hydrophobic portion and a hydrophilic portion, the hydrophilic portion having at least about 100 units of ethylene oxide. and a viscosity stabilizer, wherein the polyalkylene oxide nonionic surfactant is present in an amount sufficient to disperse the granular coal in the water. The coal-water slurry of this invention consists of coal or other carbonaceous material as a dispersed solid, water as a carrier medium, and a polyalkylene oxide nonionic surfactant as described below. The "polyalkylene oxide nonionic surfactant" mentioned here refers to the formula: It includes all compositions, compounds, mixtures, polymers, etc. that have an alkylene oxide repeating unit, have a hydrophobic part and a hydrophilic part, and are not dissociated or ionized in solution. These surfactants have the general formula: It has a polymer portion consisting of repeating units of ethylene oxide. Additionally, the polyalkylene oxide nonionic surfactants used in the present invention, depending on the particular surfactant used, have a high molecular weight, i.e., greater than about 4000, are hydrophilic, and have at least about 100 repeating units of ethylene oxide monomer. has. Additionally, the surfactant used has a hydrophobic portion and a hydrophilic portion and is nonionic. Being nonionic, these compositions generally do not undergo ionization in aqueous acid or alkaline solutions. Preferred hydrophilic polyalkylene oxide nonionic surfactants for use in the present invention are commercially available glycol esters of alkylphenols of the formula: Here, R has 1 to 18 carbon atoms, preferably 9 carbon atoms.
is a substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or amino group, and n is at least about
It is an integer of 100. These nonionic surfactants can have a wide range of molecular weights depending primarily on the value of n, ie, the number of ethylene oxide repeat units. Surprisingly, these high molecular weight surfactants with n of at least 100 and greater than about 4000 can improve coal-aqueous mixtures with high coal solids concentrations requiring little other additives to form highly fluid liquids. It has been found that it exhibits remarkable effectiveness as a dispersant for forming. Methods for preparing glycol ethers of the formula are well known and are disclosed, for example, in US Pat. No. 2,213,477, the disclosure of which is incorporated herein by reference.
Generally, the preparation of these compositions utilizes the condensation of substituted phenols with molar proportions of ethylene oxide monomer. The polyalkylene oxide nonionic surfactants preferably used in the present invention contain at least about 4,000
There are glycol esters of alkylated phenols of the following formula with a molecular weight of: Here, R has 1 to 18 carbon atoms, preferably 9 carbon atoms.
is a substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or amino group, and n is at least about
It is an integer of 100. Substituents for alkyl and aryl groups include halogen, hydroxy, and others. Other preferred nonionic surfactants are poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene) or as mentioned elsewhere.
There is a propoxylated, ethoxylated propylene glycol nonionic surfactant block polymer of the following formula having a molecular weight of at least about 6000: HO(CH ₂ CH ₂ O)a [CH(CH ₃ )CH ₂ O]b
(CH ₂ CH ₂ O)cH where a, b, and c are integers, and the sum of a and c is at least about 100. Still other polyalkylene oxide nonionic surfactants preferably used in the present invention include block polymers of ethylene and propylene oxide derived from nitrogen-containing components such as ethylene diamine and having a molecular weight of at least about 14,000. . : Here, R ₁ is an alkylene group having 2-5 carbon atoms, preferably 2, and R ₂ is an alkylene group having 3-5 carbon atoms, preferably 3.
alkylene groups, a, b, c, d, e, f, g,
h is an integer, and the sum of e, f, g, and h is at least approximately
It is 100. Preferred coal-water mixture compositions of the present invention have a high coal solids content and are tested on a Bruckfield viscometer, e.g., Model #RVT, with 3 spindles.
Based on the total weight of the mixture when measured at 100 rpm
Even at solids levels of 70% by weight or higher, approximately 2000
It is characterized by a relatively low viscosity of -6000 centipoise (cp). Depending on the intended use, such compositions may contain conventional flow modifying substances such as thickeners, grays, defoamers, salts, and the like. The products of this invention contain small amounts of surfactant additives on the order of about 0.1-3.0% by weight. They also contain granular coal as dispersed solids in an amount of about 45-80%;
water as a carrier medium in an amount of about 19.9-52% and optionally a thickening agent of about 0.1-2%, about 0.01-2%
of defoamers and about 0.1-2% of salts, antimicrobials, caustic and other additional flow control agents. All percentages here are based on the total weight of the mixture. The most preferred glycol ether of the type generally represented by the formula is a nonylphenoxy(polyethyleneoxy)ethanol composition of the formula: Here, n represents about 100 or more. Commercial surfactants of this type are IGEPAL CO−
It is available from GAF under the trade names 990 and IGEPAL CO-997. Other commercially available surfactants of this type are sold by Thompson under the trade name T-Det N-100.
From Hayward Chemical, also ICONOL NP
-100 from Whitestone Chemical Company. As mentioned above, another group of polyalkylene oxide nonionic surfactants preferably used in the present invention is the known poly(oxyethylene)-
Poly(oxypropylene)-poly(oxyethylene) nonionic surfactant block polymer. These surfactants have a block polymer of ethylene oxide and propylene oxide consisting of repeating units of propylene oxide constituting the hydrophobic portion and repeating units of ethylene oxide constituting the hydrophilic portion. These block polymer compositions have the following formula: HO(CH ₂ CH ₂ O)a [CH(CH ₃ )CH ₂ O]b
(CH ₂ CH ₂ O)cH where a, b, c are integers and the total number of a and c is at least 100. These compositions can be manufactured and commercially available in a wide range of molecular weights, depending primarily on the number of repeating units of ethylene and propylene oxide. These block polymers having a molecular weight of at least about 6000 and having at least about 100 ethylene oxide repeating units have a desired high coal solids content, such as about 45-80%, preferably about 70%, of the coal particles by weight of the total mixture. It has been found to be an excellent dispersant for dispersing coal in a water carrier at high concentrations. Therefore, in the above formula, in the poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene) nonionic surfactant preferably used in the present invention, a, b, and c are integers, and the sum of a and c is is about 100 or more. Methods for making block polymers of the formula are disclosed, for example, in US Pat. Generally, these block polymers are created by the controlled addition of propylene oxide to the two hydroxyl groups of propylene glycol to create a hydrophobe, and then ethylene oxide is added between two hydrophilic polyethylene oxide groups so that the hydrophobe is a sandwich sandwich. Manufactured by controlled addition of Nonionic surfactants of this type (formula) having as a prerequisite at least 100 ethylene oxide units are sold under the PLURONIC trade name with serial numbers F-77, F-87, F-68, F-88, F-127, F
-98, F-108 from BASF-Wyandotte. These compositions have at least 100 ethylene oxide units as shown in the table below for PLURONIC surfactants.

[Table] As mentioned above, another group of polyalkylene oxide nonionic surfactants preferred as coal dispersants include nitrogen-containing block polymers of the following formula: Here, R ₁ is an alkylene group having 2-5 carbon atoms, preferably 2, and R ₂ is an alkylene group having 3-5 carbon atoms, preferably 3.
alkylene groups, a, b, c, d, e, f, g,
h is an integer, and the sum of e, f, g, and h is at least
It is 100. These materials are produced by adding a _C3 - _C5 alkylene oxide to an alkylene diamine in the presence of a catalyst and polymerizing the oxyalkylene group into a long-chain polyalkylene group under conditions that add two polyoxyalkylene groups to each nitrogen atom. Manufactured by After the desired addition of C ₃ -C ₅ alkylene oxide and polymerization is complete, ethylene oxide is added and added to the polyalkylene group to impart the desired hydrophilicity to the compound. The preparation of these materials from commercially available alkylene diamines and alkylene oxides is known. Generally, this reagent combines a _C3 - _C5 alkylene oxide and an alkylene diamine at atmospheric or elevated pressure at a temperature of about 50-150°C in the presence of an alkaline catalyst such as an alkali metal hydroxide or alcoholate. It is manufactured by mixing.
The degree of polymerization is controlled by the length of the hydrophobic group and the relative ratio of _C3 - _C5 alkylene oxide and alkylene diamino, with alkylene oxide being added in sufficient quantity to obtain a hydrophobic group weight of approximately 2000-3600 units. Normal. Other weights may also be used. These surfactants (formula) with at least 100 ethylene oxide repeat units are
TETRONIC product name with serial numbers 1107, 1307,
908 and 1508 from BASF Wyandotte Chemical. These compositions are TETRONIC
It has at least 100 ethylene oxide units as can be seen from the following table for surfactants.

Table: A wide variety of coals can be used to make the coal-water mixture of the present invention. Examples include anthracite, bituminous coal, subbituminous coal, minetailing, fine powder, and lignite. Other finely divided solid carbonaceous materials may also be used, such as coke made from coal or petroleum. The coal is optionally ground to about 90% finer than 200 mesh on a Tyler standard screen size to form a coal-water mixture. Of course, it may be coarser or finer than this. According to the invention, preferably untreated pulverized raw material coal is beneficent. In other words, ash and sulfur are washed away. Mixtures from beneficent coal offer many advantages. These allow clean burning and can be suitably used for burning in equipment such as electric power facilities and home burners without undue burden or expensive cleaning equipment. A wide range of beneficiation processes can be used to make granular coal. These include conventional heavy liquid beneficiation, magnetic separation, etc. A preferred method of obtaining beneficiary coal particles is a chemical treatment method as disclosed in US Pat. No. 4,304,573. Generally, the preferred chemical beneficiation process involves grinding mined coking coal in the presence of water to approximately 200
Reduce the particle size to mesh. The pulverized coal is usually treated in an aqueous medium with monomeric compounds typified by unsaturated polymerizable compositions such as readily available tall oil fatty acids. By sharing a small amount of fuel oil with a metal initiator such as cupric nitrate, the treated pulverized coal becomes hydrophobic, lipophilic, and separated from undesirable ash and sulfur by flotation. Washed coal in the form of beneficent coal particles obtained by the preferred chemical treatment method described above is suitable for use in the coal-water mixture of the present invention. These coal particles have an ash content of approximately
Also the sulfur content is about 0.5-2.0 to the level of 5.0-6.0%
It is characterized by a decrease to the level of %. As disclosed in U.S. Pat. No. 4,358,293, the present invention involves first adding a surfactant to water to form a coal-water mixture, optionally along with other additives such as commercially available defoamers. It is preferable.
This mixing may be carried out with stirring at or near room temperature and at or near atmospheric pressure. Granular coal, preferably beneficent coal particles, is then added to the mixture at or near room temperature and at or near atmospheric pressure, resulting in a high coal solids content of about 45-80% by weight of the coal based on the total weight of the mixture. to produce a coal-water mixture having a Optionally, a thickening agent is then added to further stabilize the mixture and help ensure that the mixture can be stored for long periods of time without the risk of sedimentation of the coal particles. Caustic soda or other base may also be added at this point. Obviously, it is preferred to add the thickening agent near the final stage to minimize agitation. Coal-water mixtures can be prepared in batch or continuous processes. In a continuous process, coal is mixed with water in a first stage along with other flow control agents such as surfactants. The first stage composition is then continuously transferred to a second stage where a thickening agent is added. Agitation may be reduced by adding a thickening agent at a later stage as described above. In accordance with the present invention, unique conditions have been discovered that allow improved coal-water mixtures to be produced and to avoid problems such as deleterious foaming and agglomeration during operation. Specifically, in the production of the coal-aqueous mixture of the present invention, a surfactant of the present invention and, if desired,
Other additives, such as conventional defoamers, are first added to the water under low speed stirring, such as from about 500 rpm to about 1500 rpm, preferably about 100 rpm, for about 30 seconds to about 3 minutes, preferably about 1 minute. Mix. Granular coal, preferably beneficent coal particles, is then added to the mixture and mixed under medium speed stirring, such as from about 1000 rpm to about 3000 rpm, preferably about 2000 rpm, for a sufficient time to wet the mixture. Typically this time ranges from about 5 minutes to about 20 minutes. At this point, the mixture is agitated at high speed, for example from about 3000 rpm to about 6000 rpm, preferably about 4000 rpm, and mixed for a sufficient time to disperse the coal, usually about 5 minutes to about 15 minutes, preferably about 10 minutes. do. If desired, the thickening agent may be added under the high speed stirring conditions described above, e.g.
Add to the slurry at 4000 rpm for an additional period of about 1 minute to about 3 minutes, preferably about 2 minutes.
Most preferably, other ingredients such as viscosity stabilizers and antimicrobial agents are then added under high speed agitation and mixed for an additional period of about 1 minute to about 3 minutes, preferably about 2 minutes. In the above, wet means that the surface of each coal particle is covered with water. An example of a typical mixing or dispersing device that can be used in the present invention is Premier Mill's Hi-Vispersator.
There are high-speed dispersers, etc. It should be understood that the residence times, temperatures, mixing rates, etc. described above may vary depending on process characteristics such as component amounts, equipment size, mixing efficiency, etc. Therefore, the above operating conditions of the present invention can be adjusted depending on the scale of operation, such as whether it is a pilot plant or a main plant. It has been found that by using the specific conditions of the present invention, the coal is well dispersed in the surfactant/anti-foaming solution at a relatively low viscosity, despite the surfactant being oriented at the coal-water interface. The anti-foaming agent, or antifoam agent, controls the level of foaming caused by the surfactant being stirred into the solution. After the coal is properly dispersed, a thickening agent is added to create a protective colloid that imparts desirable ological properties and suspendability. As mentioned above, additives that may be added to the coal-water mixture include defoamers, admixtures, salts, bases, other flow improvers, and combinations thereof. Defoamers that can be used are generally readily available and include silicone-containing and silicone-free compositions. Colloids' defoamers are commercially available.
There is COLLOID691. The above composition is usually mineral oil,
Consisting of an amide and ester containing mixture. Thickening agents may also be added; these are added to increase the non-sedimentation properties of the composition. Preferred thickening agents include, for example, xanthan gum, guar gum, and gray. Other thickeners include
For example, alkali-soluble acrylic polymers (e.g. ACRYSOL ICS-1 from Rhohm and Haas)
There is. Combinations of these thickening agents are also preferred. In the present invention, thickeners are typically used in an amount of about 0.01 to about 3.0% by weight, based on the total weight of the mixture. In the preparation of compositions containing preferably 70% coal by weight based on the weight of the total mixture, the polyalkylene oxide nonionic surfactant is added to water at or near room temperature and at or near normal pressure.
Preferably, it is mixed with water in a ratio of about 0.3 parts by weight to 29.3 parts by weight. The defoamer is preferably added to the water in an amount of about 0.03 parts by weight to aid in handling. The pulverized coal is then mixed with water in a ratio of 29.3 parts by weight of water to 70 parts by weight of coal to obtain a fluid liquid. Optionally, about 0.12 to 0.15 parts by weight of a thickening agent is added to the mixture to protect against settling. Other additives such as salts and bases, antibacterial agents such as formaldehyde, viscosity stabilizers such as ammonia, etc.
Addition of 0.2 to 0.3 parts by weight can assist in the dispersion of coal or impart other properties. Next, the present invention will be explained with reference to Examples. Example 1 Preparation of coal-water mixture A coal-water mixture having the following composition was prepared using ordinary pulverized coal (hereinafter referred to as "pulverized coal").

[Table] Approximately 90% of the coal was crushed finer than the 200 mesh of the Tyler standard sieve. Surfactants, anti-foaming agents, and salts were applied in the amounts specified above using a Premium Mill "Hi-Vispersator" equipped with a 1 3/4-inch Cowles-type blade running at 2000 rpm. - 29.37 g of water in a high-speed stirrer called Vispersator. The stirrer was running at room temperature and pressure. Pulverized coal was then added to this mixture while it continued to mix. The mixture had a total of 70 g. % of coal by weight and was observed to flow freely. Example 2 Preparation of Coal-Water Mixture Another common pulverized coal was used to prepare a coal-water mixture with the following composition: .

【table】

[Table] Approximately 90% of the coal was crushed finer than the 200 mesh of Tyler's standard sieve. The surfactant, defoamer and salt were added in the amounts specified above to 29.46 g of water in a high speed stirrer with a 13/4 inch cowl type blade running at 2000 rpm with continued mixing. Then pulverized coal was added to the mixture. The capacity was operated at normal temperature and pressure. This mixture was found to disperse a total of 70% by weight of coal and was observed to flow freely. Example 3 Preparation of Cleaned Pulverized Coal 200 g of Pittsburgh Formation coal having an ash content of 6.3% and a sulfur content of 1.5% on a dry coal weight basis was ground in a Volmill mill in the presence of water. Milled to Tyler's standard size of 200 mesh. The coal was then transferred to a mixing tank. This tank contains 0.03 g of corn oil, 5.0 g of No. 2 fuel oil, 1.0 cm ³ of a 5% aqueous solution of hydrogen peroxide; 5.0 cm of copper nitrate.
% ^aqueous solution and 200 g of 200 mesh coal were added. The mixture was stirred and heated to 86°C for 2 minutes.
The mixture was sprinkled on the water surface and observed to foam.
The coal present in the foam phase and having an ash content of 3.4% and a sulfur content of 0.9% based on the weight of dry coal was skimmed from the water surface and recovered. The aqueous phase containing large amounts of ash and sulfur was discarded. The recovered coal was slightly dried using a Buchner overdryer. Example 4 Preparation of Coal-Water Mixture A coal-water mixture of the following composition was formed with advantageous coal treated according to the method of Example 3.

Table: Surfactant, defoamer, and salt were added in the specified amounts to 29.04 g of water in a high speed stirrer with a 13/4 inch cowl type blade running at 2000 rpm. The stirrer was operated at room temperature and pressure. next,
Pulverized coal was added to the mixture while stirring at 4500 rpm. Next, xanthan gum and guar gum thickener were added to the mixture while stirring at 4500 rpm. The mixture was determined to have a total of 70.21% by weight dispersed coal particles and was observed to be free flowing. The viscosity was 2000 cp at 100 rpm as measured by a Brookfield viscometer model #RVT using a #6 spindle. Example 5 Preparation of Coal-Water Mixture A coal-water mixture of the following composition was formed with advantageous coal treated according to the method of Example 3.

[Table] Specified amounts of surfactant and de-foaming agent,
Added to 29.56 g of water in a high speed stirrer with a 1 3/4 inch Yuuru type blade running at 2000 rpm. The stirrer was operated at room temperature and pressure. next,
Pulverized coal was added to the mixture while stirring at 4500 rpm. Xanthan gum and guar gum thickener were then added to the mixture while stirring at 4500 rpm. The mixture was determined to have a total of 70.00% by weight dispersed coal particles and was observed to be free flowing. The viscosity measured by a Burckfield viscometer #RVT type using a #6 spandle is
It was 2000cp at 100rpm. EXAMPLES 6-14 These examples illustrate similar mixtures that can be prepared to high coal solids concentrations using high loadings and polyalkylene oxide nonionic surfactants having at least 100 ethylene oxide repeating units in this composition. Comparing 100 repeating units of ethylene oxide, which is a surfactant but is required, and a mixture in which the coal is not dispersed to high solids concentrations when a surfactant that does not have a high molecular weight is used. . Each experiment used the same or substantially the same amounts of pulverized coal, water, thickener, salt, and defoamer. and similar surfactants except that different surfactants with different molecular weights and different numbers of ethylene oxide repeating units were tested, namely poly(oxyethylene)-poly(oxypropylene)-poly(oxyethylene). was used. Each mixture was prepared according to the method of Example 4. The surfactant, defoamer, and salt were added in the specified amounts to the water in a high speed stirrer equipped with a 13/4 inch Yuur type blade running at 2000 rpm. The stirrer was operated at room temperature and pressure. Pulverized coal was then added to the mixture while stirring was continued. Next, predetermined amounts of xanthan gum and guar gum thickener were added with stirring. Table A below summarizes the results of Examples 6-14 and shows that poly(oxyethylene)-poly(oxypropylene)-polymers having the required 100 repeating units of ethylene oxide and a molecular weight greater than 6000 Coal dispersions with high solids concentrations have been prepared using (oxyethylene) surfactants, whereas using surfactants without the required 100 repeating units of ethylene oxide and high molecular weight are identical. This indicates that the amount or substantially the same amount of coal was not completely dispersed.

【table】

[Table] Examples 15-21 These examples demonstrate that high coal solids concentrations can be prepared using polyalkylene oxide nonionic surfactants with high molecular weights and at least 100 ethylene oxide repeating units in their composition. , when a similar surfactant is used, but does not have the required 100 repeating units of ethylene oxide and a high molecular weight, it is possible to create a mixture in which the coal is not dispersed to a high solids concentration. are being compared. Each experiment used the same or substantially the same amounts of pulverized coal, water, thickener, salt, and defoamer. Similar surfactants were used, and different surfactants with different molecular weights and different numbers of ethylene oxide repeating units were tested, ie, nitrogen-containing block polymers of propylene oxide and ethylene oxide. Each mixture was prepared according to the method of Example 4. The surfactant, defoamer, and salt were added in the specified amounts to the water in a high speed stirrer equipped with a 13/4 inch Yuur type blade running at 4500 rpm. The stirrer was operated at room temperature and pressure. Pulverized coal was then added to the mixture while stirring was continued. Next, predetermined amounts of xanthan gum and gal gum thickener were added with stirring. Table B below summarizes the results of Examples 15-21 and shows that the interface between nitrogen-containing block polymers of propylene oxide and ethylene oxide has the required 100 repeating units of ethylene oxide and a molecular weight greater than 14,000. It was shown that coal dispersions with high solids concentrations were prepared using activators, whereas using surfactants without the requisite 100 ethylene oxide repeating units and high molecular weights, the same amount of coal could be dispersed. It shows that it has disappeared. Tetronics 1107,
1307, 908, and 1508 have high ethylene oxide to propylene oxide ratios, i.e., greater ethylene oxide content than propylene oxide content, while Etronix 304, 504, and 704 have high propylene oxide to ethylene oxide ratios. ratio, ie, the propylene oxide content is greater than the ethylene oxide content.

[Table] Examples 22-28 These examples demonstrate that high coal solids concentrations can be prepared using polyalkylene oxide nonionic surfactants with high molecular weights and at least 100 ethylene oxide repeating units in their composition. , when a similar surfactant is used, but does not have the required 100 repeating units of ethylene oxide and a high molecular weight, it is possible to create a mixture in which the coal is not dispersed to a high solids concentration. are being compared. Each experiment used the same or substantially the same amounts of pulverized coal, water, thickener, salt, and defoamer. A similar surfactant was used, except that different surfactants with different molecular weights and different numbers of ethylene oxide repeating units were tested, namely glycol ethers of alkylated phenyls. Each mixture was prepared according to the method of Example 4. The surfactant, defoamer, and salt were added in the specified amounts to the water in a high speed stirrer equipped with a 1 3/4 inch Yuur type blade running at 4500 rpm. The stirrer was operated at room temperature and pressure. Pulverized coal was then added to the mixture while stirring was continued. Next, predetermined amounts of xanthan gum and guar gum thickener were added with stirring. Table C below summarizes the results of Examples 22-28 and shows that high solids were obtained using an alkylated phenol glycol ether surfactant with the required 100 ethylene oxide repeating units and a molecular weight greater than 4000. It has been shown that a coal dispersion with a high concentration can be prepared, while using the requisite 100 repeating units of ethylene oxide and a surfactant without high molecular weight, the same or substantially the same amount of coal can be completely absorbed. This shows that it was not dispersed.

Table: As in the examples shown, coal-water mixtures are prepared with high coal solids content. The resulting mixture is stable, has a low viscosity, and contains a large amount of solid coal particles, typically 70% or more by weight coal. Examples 6-14 demonstrate that high molecular weight polyalkylene oxide nonionic surfactants of at least 6000 having at least 100 repeating ethylene oxide units are excellent dispersants for the formation of coal-water mixtures. ing. Examples 6 to 14 further show that for surfactants of the same basic structure, i.e. blocks of propylene oxide and ethylene oxide, compositions with a molecular weight of 6000 or compositions with at least 100 repeating ethylene oxide units were used. It has been shown that advantageous results are achieved when used. Similarly, Examples 15 to 20 are block polymer type polyalkylene oxide nonionic surfactants derived from nitrogen-containing compositions such as ethylene diamine, compositions having a molecular weight of 14,000 or greater than 100 ethylene oxide repeating units. have been shown to produce the same or nearly the same advantageous results. Similarly, Examples 22-28 show that alkylated phenol glycol ether surfactants with 100 ethylene oxide repeating units and high molecular weights are also excellent coal dispersants. Example 29 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Ingredients were added in the order listed. A high speed agitator, ie, a Hi-Vispersator, was used to agitate, mix and disperse the materials into a stable homogeneous slurry. Components 1, 2 and 3 are stirred together at low speed (1000 rpm) for 1 minute. Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredients 5 and 6.
Add. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. Example 30 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various Ingredients were added in the order listed. high speed stirrer,
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials into a stable, homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. Next add ingredients 5 and 6 while stirring at high speed. After 2 minutes, add ingredients 7 and 8,
After stirring at high speed for an additional 2 minutes, the batch was considered complete. All mixing was done at room temperature and pressure. Example 31 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

【table】

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various Ingredients were added in the order listed, using a high-speed stirrer;
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials into a stable, homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for a sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredient 5.
and 6 are added. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. Example 32 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

【table】

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various Ingredients were added in the order listed. high speed stirrer,
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials to form a stable homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredient 5.
and 6 are added. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. Example 33 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

【table】

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various components were added in the order listed. high speed stirrer,
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials into a stable, homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredient 5.
and 6 are added. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. Example 34 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various components were added in the order listed. high speed stirrer,
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials to form a stable homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredient 5.
and 6 are added. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. Example 35 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various components were added in the order listed. high speed stirrer,
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials to form a stable homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredient 5.
and 6 are added. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. Example 36 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various components were added in the order listed. high speed stirrer,
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials to form a stable homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredient 5.
and 6 are added. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. Example 37 The following formulation was used to prepare a water-coal slurry according to the improved method of the present invention.

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various Ingredients were added in the order listed. high speed stirrer,
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials to form a stable homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredient 5.
and 6 are added. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. Example 38 The following formulation was used to prepare a water-coal slurry in accordance with the improved method of the present invention.

【table】

[Table] Slurry properties solid −70.0±1.0 PH −8.0±1.0 Burtskfield viscosity, cp 10rpm −14000±4000 100rpm −6500±1500 Sedimentation (spatial test) 6Weeks −None 8Weekes −A small amount of soft sediment Various Ingredients were added in the order listed. high speed stirrer,
That is, a Hi-Visperzer was used to agitate, mix, and disperse the materials to form a stable homogeneous slurry.
Components 1, 2 and 3 are all at low speed (1000 rpm) for 1 minute.
Stir with Coal is added to this solution at medium speed (2000 rpm) for sufficient time to wet the coal particles and disperse them in components 1, 2, and 3. The agitator speed is then increased to high speed (4000 rpm) for 10 minutes to further disperse the coal particles. While stirring at high speed, add ingredient 5.
and 6 are added. After 2 minutes, ingredients 7 and 8 were added and the batch was considered complete after an additional 2 minutes of high speed stirring. All mixing was done at room temperature and pressure. It will be appreciated that coal-water mixtures are readily provided with significantly higher solids concentrations than in the previous examples. Further cleaning to remove ash and sulfur content may be necessary only infrequently, and the mixture can be provided in a clean form that is combustible in industrial burners, domestic burners, and the like.

Claims (1)

[Claims] 1 (i) A polyalkylene oxide nonionic surfactant having a hydrophobic part and a hydrophilic part, the hydrophilic part having at least 100 units of ethylene oxide, mixed with water under low speed stirring conditions. (ii) mixing the granulated coal with the mixture obtained in step (i) under medium speed stirring; and (iii) stirring the coal-containing mixture obtained in step (ii) under high speed stirring. A method for forming a characterized coal-aqueous mixture. 2. The method according to claim 1, wherein the medium-speed stirring in step (ii) is carried out for a sufficient time to moisten the coal particles, and the high-speed stirring is carried out for a sufficient time to disperse the coal. 3. The method according to claim 1 or 2, wherein an antifoaming agent is added in step (i). 4. The method of claim 3, wherein the anti-foaming agent comprises a mixture of mineral oil, amide and polyethylene glycol oleate ester. 5. Add granular coal in an amount of about 45-80% based on the total weight of the mixture, add water in an amount of about 19.9-52%, and add polyalkylene oxide nonionic surfactant in an amount of about 0.1-3.0%.
Claims 1 to 4 consisting of an amount of %
The method described in any of the paragraphs. 6 Polyalkylene oxide nonionic surfactant formula (wherein R is a substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or amino group having 1 to 18 carbon atoms, and n is an integer of at least about 100) (Here, R ₁ is an alkylene group having 2-5 carbon atoms,
R ₂ is an alkylene group having 3-5 carbon atoms, a, b, c,
d, e, f, g and h are integers of 1 or more, e,
the total number of f, g and h is at least about 100)
Compound or formula HO(CH ₂ CH ₂ O) _a [CH(CH ₃ )CH ₂ O] _b
(CH ₂ CH ₂ O) _c H (wherein a, b and c are integers of 1 or more, and the total number of a and c is at least about 100) The method described in any of the paragraphs. 7. The method of any of claims 1-6, wherein the polyalkylene oxide nonionic surfactant has a molecular weight of at least about 4000. 8. The method according to claim 6, wherein R ₁ is an alkylene group having 2 carbon atoms, R ₂ is an alkylene group having 3 carbon atoms, and R is nonyl. 9. A method according to any one of claims 1 to 8, further comprising the step of (iv) adding a thickening agent to the mixture from step (iii) under high speed stirring. 10. The method of claim 9, wherein the thickening agent is xanthan gum, guar gum, cellulose gum, glue or alkali-soluble acrylic polymer. 11. The method of claim 9 or claim 10, further comprising (v) adding an antimicrobial agent, a viscosity stabilizer, or a mixture thereof to the mixture from step (iv) under high speed stirring. 12. The method of claim 11, wherein the viscosity stabilizer is ammonia. 13. Claims 1 to 12, wherein the granular coal has a sulfur content of 0.5-2.0% by weight based on dry coal weight, an ash content of about 0.5-6.0%, and is about 200 mesh (Tyler standard mesh size). The method described in any of the paragraphs. 14 Granular coal as a dispersed solid material, water as a carrier medium, having a hydrophobic portion and a hydrophilic portion, the hydrophilic portion being at least about ethylene oxide.
100 units of a polyalkylene oxide nonionic surfactant and a viscosity stabilizer, wherein the polyalkylene oxide nonionic surfactant is present in an amount sufficient to disperse the granular coal in the water. High solids content coal-water mixture. 15. A stabilized high solids content coal-aqueous mixture according to claim 14, further comprising a thickening agent and/or an antifoaming agent. 16 The polyalkylene oxide nonionic surfactant has the formula (wherein R is a substituted or unsubstituted alkyl, substituted or unsubstituted aryl, or amino group having 1 to 18 carbon atoms, and n is an integer of at least about 100) (Here, R ₁ is an alkylene group having 2-5 carbon atoms,
R ₂ is an alkylene group having 3-5 carbon atoms, a, b, c,
d, e, f, g and h are integers of 1 or more, e,
the total number of f, g and h is at least about 100)
The compound or formula HO(CH ₂ CH ₂ O)a [CH(CH ₃ )CH ₂ O]b
Claim 14 or 15 consisting of a compound consisting of (CH ₂ CH ₂ O) cH (where a, b and c are integers of 1 or more, and the total number of a and c is at least about 100) A stabilized high solids content coal-aqueous mixture as described. 17. The stabilized high solids content coal-aqueous mixture of claim 16, wherein R ₁ is a C 2 alkylene group, R ₂ is a C 3 alkylene group, and R is nonyl. 18. The stabilized high solids content coal-aqueous mixture of any of claims 14-17, wherein the polyalkylene oxide nonionic surfactant has a molecular weight of at least about 4000. 19. A stabilized high solids content coal-water mixture according to any of claims 14 to 18, wherein the viscosity stabilizer comprises ammonia.