JPH0453589B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to coal beneficiation. For more details,
The present invention relates to an improved method for beneficiation of coal and separation of impurities from coal and for the production of stable beneficiation coal mixtures such as coal oil. The world's known resources of coal and other solid carbonaceous fuel materials are much larger than the combined known resources of oil and natural gas.
Despite this enormous abundance of coal and related solid carbonaceous materials, reliance on these resources, particularly coal, as a primary energy source has largely been abandoned. Cheaper, cleaner-burning, more easily recoverable, transportable fuels such as oil and natural gas have played a largely supportive role in the energy sector in the past. However, current global trends have created a new awareness of global energy needs and the availability of these resources to adequately meet these demands. The real feeling of stockpiling oil and natural gas is that, along with soaring oil and natural gas prices, they are rapidly depleting, and the uncertainty in the regions of the world that contain the largest amounts of these resources has led to the decline in the use of solids as a primary energy source. There has been renewed interest in the use of carbonaceous materials, especially coal. As a result, great efforts are being made to make coal and related solid carbonaceous materials as good or better energy sources as oil or natural gas. For example, in the case of coal, much of this effort is directed toward overcoming environmental problems associated with its production, transportation, and combustion. For example, the health and safety risks associated with coal mining have decreased significantly with the introduction of new legislation governing coal mining. Additionally, numerous techniques are being explored and developed to make coal cleaner to burn, more suitable for combustion, and easier to transport. Coal gasification and liquefaction are two such known technologies. For more information on various coal gasification and liquefaction methods, see e.g.
of Chemical Technology (Encyclopedia)
of Chemical Technology), Kirk-Othmer, 3rd edition (1980), Vol.
Described on pages 410-422 and 449-473.
However, these techniques characteristically require high energy input and the use of high temperature, high pressure equipment;
This reduces their widespread practical applicability and evaluation. Methods have also been developed to make coal more easily liquefiable. One such method is disclosed in U.S. Pat. No. 4,033,852 (Horowitz et al.), which involves chemically modifying the surface portion of coal in a solvent medium to The purpose of this invention is to make the coal more easily liquefiable in solvents than coal in its natural form, thereby making it possible to extract sticky products that can be liquefied by extraction.In addition to gasification and liquefaction, coal Other methods for converting into forms more convenient for combustion and transportation are also known; for example, the production of coal oil and coal-water mixtures is disclosed in the literature.
Such liquid coal mixtures offer considerable benefits. In addition to being more easily transportable than dry solid coal, these mixtures are easier to store and have less potential for explosion hazards due to spontaneous combustion. Furthermore, by providing the coal in liquid form, it is feasible to burn it in conventional equipment used to burn fuel oil. This capability greatly facilitates the transition from burning oil to coal as the primary energy source.
Representative coal oils and coal-water mixtures and their preparation are described in U.S. Pat. No. 3,762,887;
No. 4217109, No. 4101293 and British Patent No. 1523193. However, regardless of the form in which the coal is ultimately used, the coal or coal combustion products must be clean. This is because they contain substantial amounts of minerals, including sulfur, nitrogen compounds and significant amounts of metal impurities. During the combustion process these substances enter the atmosphere as compounds of sulfur dioxide, nitrogen oxides and metal impurities. If coal is to be accepted as a primary energy source, it must be cleaned to prevent air pollution by cleaning the combustion products of the coal or the coal before combustion. Therefore, physical and chemical coal beneficiation methods are being explored. Generally, physical coal screening methods involve pulverizing the coal to release impurities, where the fineness of the coal generally controls the degree to which impurities are released. However, since the cost of producing this coal increases exponentially with the amount of powder to be processed, there is an economic optimum in size reduction. Additionally, grinding coal to extremely fine sizes may not be effective in removing all impurities. Based on the physical properties that separate coal from impurities, physical coal cleaning methods generally fall into four categories: gravity, flotation,
Classified into magnetic and electrical methods. In contrast to physical coal cleaning, chemical coal cleaning technology is at a very early stage of development. Known chemical coal cleaning techniques include, for example, oxidative desulphurization of coal (converting sulfur to water-soluble form by air oxidation), ferric salt leaching (oxidation of pyrite sulphide mineral sulfur with ferric sulfate), and peroxidation. Includes hydrogen oxide-sulfuric acid leaching. Other methods are also available in the Encyclopedia of Chemicals.
Technology, Volume 6, pages 314-322, supra. While it is clear from the foregoing that significant efforts are being made to make coal a more usable energy source, further work and improvements are being made on coal, coal blends, and other solid carbonaceous fuel sources. is still necessary and desirable before it can be accepted as a primary energy source on a global scale. Therefore, the present invention involves contacting coal with a surface-treating mixture consisting of a polymerizable monomer, a polymerization catalyst and a liquid organic carrier in an aqueous medium, thereby further removing ash and sulfur by water separation techniques. The present invention relates to a method comprising providing a hydrophobic and lipophilic coal product adapted to do so.
The resulting product is highly suitable for the production of beneficent coal slurry and/or beneficent granular coal. Additionally, in accordance with another aspect of the present invention, an improved method for beneficiation of coal is provided, which method comprises chemically surface treating coal in an aqueous medium to render it hydrophobic and lipophilic; The special modification consists in separating the hydrophobic, oleophilic coal phase from the ash-containing aqueous phase, and the special modification involves subjecting the chemically surface-treated hydrophobic, oleophilic coal to high shear mixing with an aqueous cleaning medium. The hydrophobic coal phase then floats on top of the aqueous phase and separates. According to the present invention, a highly beneficent coal product is produced by the following method. That is, this method uses monomers capable of polymerizing coal particles in an aqueous medium;
The method includes surface-treating the coal particles with a surface-treating mixture comprising a polymerization catalyst and a liquid organic carrier, thereby making the coal particles hydrophobic and lipophilic. That is, the process of the present invention provides a highly beneficent coal product with relatively low moisture content that can be further dehydrated (dryed) to a significant extent without the use of thermal energy. The ash content of the coal produced by the method of the invention has been reduced to low concentrations and the mineral sulfur compounds present have also been removed. Additionally, the final coal product has an increased BTU content and can be burned as a solid or with fuel oil or water, making it a highly desirable beneficent coal mixture or slurry that is easily transportable and burns cleanly. can be generated. As used in this text, the term "benefication" refers to the cleaning or otherwise removal of impurities from a substrate, e.g. coal, and the extraction of coal from a coal stream, e.g. from the waste stream of a coal processing operation. It is contemplated to include methods of harvesting and concentrating or dewatering a coal stream or slurry, such as by removing water in a coal slurry pipeline. In one embodiment of the present invention that uses mined coking coal as a feedstock, the coking coal or other solid carbonaceous material is reduced to a fine diameter size and freed from unwanted rock, heavy ash, and mined coal. It is initially preferred to remove similar materials collected during the operation. The coal is then pulverized and initially screened, usually in the presence of water, where the coal is suspended and/or sufficiently moistened to allow fluid flow. The coal is pulverized using conventional equipment such as ball or rod mills, breakers, etc. Although not essential to the process of the present invention, it is generally desirable to use certain moisture control (treatment) additives in the milling operation. This additive helps make the ash more hydrophilic, thereby facilitating separation of the ash in the manner discussed below. Typical additives useful for purposes of this invention include conventional inorganic and organic dispersants, surfactants and/or wetting agents. Suitable additives for this purpose include sodium carbonate, sodium pyrophosphate, and the like. The coal-water slurry formed in the milling operation typically has a coal to water ratio of about 0.5:1 to about 1:5, preferably about 1:3 parts by weight, respectively. If used, the water treatment additives described above are usually used in small amounts, such as from about 0.25 to about 5%, based on the weight of dry coal. Although it is generally accepted that more impurities are liberated as the size of the coal decreases, the law of diminishing returns applies in the sense that there is an economic optimum governing the degree of comminution. In any event, for purposes of this invention, coal is
It is generally desirable to crush particles to a particle size of 325 mesh or less, with approximately 80% of particles having a particle size of about 200 mesh (Tyler Standard Screen).
(Tyler Standard Screen Size)]. Any type of coal can be used in the method of the invention. Typically, these include, for example, bituminous coal, subbituminous coal, anthracite coal, lignite, and the like. Other solid carbonaceous fuel materials such as oil shale, tar sands, coke, graphite, tailings, coal from waste coal piles, coal processing fines, coal fines from mine ponds or tailings, carbonaceous excreta, etc. are also contemplated for treatment by the methods of the present invention. Thus, for purposes of the present invention, the term "coal" is also intended to encompass other solid carbonaceous fuel materials or streams of this type. In carrying out the beneficiation process of the present invention, a coal-aqueous slurry containing pulverized coal is contacted and mixed with a surface treatment mixture consisting of a polymerizable monomer, a polymerization catalyst, and a small amount of a liquid organic carrier, such as fuel oil. let Any polymerizable monomer can be used in the surface treatment polymerization reaction medium. Although it is more convenient to use monomers that are liquid at ambient temperature and pressure, it is also possible to use gaseous monomers containing olefinic unsaturation that is polymerizable with the same or different molecules. can. Thus, monomers contemplated for use in the present invention have the formula Features. Specifically, such monomers include ethylene, propylene, butylene, tetrapropylene, isoprene, butadiene, such as 1,4-butadiene, pentadiene, dicyclopentadiene, octadiene, olefinic petroleum fractions, styrene, vinyltoluene, Vinyl chloride, acrylonitrile, methacrylonitrile, acrylamide, methacrylamide, N-methylo-
lyacrylamide, acrolein, maleic acid,
Includes maleic anhydride, fumaric acid, abietic acid and the like. A preferred set of monomers for the purposes of the present invention are unsaturated carboxylic acids, esters, anhydrides or salts thereof, especially of the formula

[Formula] [wherein R is an olefinically unsaturated organic group, preferably containing about 2-30 carbon atoms, and R' is hydrogen, a salt-forming cation such as an alkali metal, an alkali Earth metal or ammonium cations or saturated or ethylenically unsaturated hydrocarbon groups (preferably 1
-containing about 30 carbon atoms], which group is substituted or unsubstituted with one or more halogen atoms, carboxylic acid groups and/or hydroxy groups, where hydroxyhydrogen may be substituted with saturated and/or unsaturated acyl groups, preferably containing about 8-30 carbon atoms. Specific monomers conforming to the above structural formula include unsaturated fatty acids such as oleic acid, linoleic acid, linolenic acid, lysyllic acid mono-, di- and triglycerides and other esters of unsaturated fatty acids, acrylic acid,
Methacrylic acid, methyl acrylate, ethyl acrylate, ethylhexyl acrylate, tertiary butyl acrylate, oleyl acrylate, methyl methacrylate, oleyl methacrylate, stearyl acrylate, stearyl methacrylate, lauryl methacrylate, vinyl acetate, vinyl stearate, vinyl myristate, vinyl laurate, Included are unsaturated vegetable seed oils, soybean oil, rosin acid, dehydrated castor oil, linseed oil, olive oil, peanut oil, tall oil, corn oil, and the like. For the purposes of the present invention, tall oil and corn oil have been found to yield particularly advantageous results. Corn oil is particularly preferred. Furthermore, it is clear that compositions containing compounds falling within the above formula and additionally containing, for example, saturated fatty acids such as palmitic acid, stearic acid, etc., are also contemplated by the present invention. Aliphatic and/or polymeric petroleum materials as monomers are also contemplated by the present invention. The amount of polymerizable monomer can vary based on the degree of surface treatment desired. However, monomer levels of about 0.005% to about 0.1% by weight of the dry coal are generally used. The catalyst used in the coal surface treatment beneficiation reaction of the present invention can be any of the materials commonly used in polymerization reactions. These catalysts include, for example, anionic, cationic or free radical catalysts. Free radical catalysts or catalyst systems (also referred to as addition polymerization catalysts, vinyl polymerization catalysts or polymerization initiators) are suitable for the present invention. Thus, in particular, free radical catalysts contemplated herein include inorganic and organic peroxides such as benzoyl peroxide, methyl ethyl ketone peroxide, tertiary butyl hydroperoxide, tertiary butyl perbenzoate, peracetic acid, peroxide Included are hydrogen, ammonium persulfate, di-tertiary butyl peroxide, and also non-epoxy free radical initiators such as diazo compounds such as 1,1'-bisazoisobutyronitrile. Typically, any contact amount of the catalyst (eg, 1 pound/ton of dry coal feed) can be used for purposes of the present invention. Additionally, free radical polymerization systems commonly use free radical initiators to help initiate the free radical reaction. For the purposes of the present invention, any of those disclosed in the prior art, such as, for example, US Pat. No. 4,033,852, incorporated herein by reference, may be used. In particular, some of these initiators include, for example, water-soluble salts such as sodium perchlorate, sodium perborate, sodium persulfate, potassium persulfate, ammonium persulfate, silver nitrate, water-soluble salts of noble metals such as platinum and gold, sulfites. salt, nitrite and iron, nickel,
Included are water-soluble salts of chromium, copper, mercury, aluminum, cobalt, manganese, zinc, arsenic, antimony, tin, cadmium, and the like. Particularly preferred initiators in this invention are water-soluble copper salts, ie cuprous and cupric salts such as copper acetate, copper sulfate and copper nitrate. The most favorable results were obtained with cupric nitrate Cu( _NO3 ) ₂ . Still other initiators contemplated by the present invention are disclosed in commonly assigned US patent application Ser. No. 230,063, filed January 29, 1981. Among other things, these initiators include metal salts of organic moieties, typically metal salts of organic acids or compositions containing organic acids such as naphthenates, talates, octanoates, etc. and other organic soluble metal salts (and thus Metals include copper, chromium, mercury, aluminum, antimony, arsenic, cobalt, manganese, nickel, tin, lead, zinc, rare earths, and mixtures thereof) and double salts of these metals. It has been found that the combination of copper and cobalt salts, especially cupric nitrate and cobalt naphthenate, provides particularly good and synergistic results. The amount of free radical initiator contemplated by this invention can be any contact amount, generally about 10-1000 ppm metal portion of the initiator based on the amount of dry coal.
(parts per million) range, preferably 10−
It is 200ppm. The surface-treating reaction mixture of the present invention also includes a liquid organic carrier. This liquid organic carrier is used to facilitate contact between the surface of the coal particles and the polymerization reaction medium. That is, liquid organic carriers included within the scope of the present invention include, for example, fuel oil such as No.
or No. 6 fuel oils, non-fuel oils, hydrocarbons including liquid organic carriers such as benzene, toluene, xylene, hydrocarbon fractions such as naphtha and medium-boiling petroleum fractions (boiling point 100-180°C); dimethylformamide, tetrahydrofuran, tetrahydrofuran. Included are furyl alcohol, dimethyl sulfoxide, methanol, ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, and mixtures thereof. The amount of liquid organic carrier, such as fuel oil, utilized in the surface treatment reaction of the present invention generally ranges from about 0.25 to about 5 percent by weight, based on the weight of dry coal. The surface treatment reaction of the method of the invention is carried out in an aqueous medium. The amount of water used for this purpose is generally about 65-95% by weight based on the weight of the coal slurry.
It is. Surface treatment reaction conditions may, of course, vary based on the particular reactants used and the desired results.
However, in general any polymerization conditions that produce a hydrophobic or lipophilic surface on the coal can be utilized. More specifically, typical reaction conditions include, for example, temperatures ranging from about 10 to 90°C, atmospheric to near atmospheric pressure conditions, and contact times ranging from about 1 second to about 30°C.
minutes, preferably from about 1 second to about 3 minutes. Preferably, the surface treatment reaction is carried out at about 15-80°C
for about 2 minutes at a temperature and atmospheric pressure of . However, longer reaction times generally enhance results. In practicing the present invention, coal can be contacted with surface treatment components using a variety of techniques.
For example, one technique is to supply an aqueous pulverized coal slurry by an atomizing means, such as a nozzle, and add to the aqueous coal spray the surface treatment components, i.e., a polymerizable monomer, a polymerization catalyst, an initiator, and a liquid organic carrier. be. The entire spray mixture obtained is then introduced into the aqueous medium contained in the beneficiation vessel. In a preferred embodiment when using this technique, the surface-treated aqueous coal mixture in the vessel is recycled into the same vessel by refeeding the mixture to the vessel by at least one of the above-mentioned spraying means. In a second technique, the aqueous coal slurry and the surface-treating components, i.e., polymerizable monomers, polymerization catalysts, initiators, and liquid organic carriers, are mixed in a premix tank and the resulting mixture is beneficent, e.g., by a nozzle. Sprayed into an aqueous medium in a container. In another third technique, the resulting surface-treated aqueous coal mixture formed in the beneficiation vessel according to the second technique described above is re-feeding the mixture into the vessel by at least one of the spraying means described above. recirculate into the same container. As the surface treatment reaction is completed, hydrophobic, lipophilic beneficiary coal particles become suspended on the surface of the liquid mass. Ash that still retains its hydrophilic properties tends to settle and migrate into the aqueous phase. So, the coal obtained from the reaction with said polymerizable surface treatment mixture is highly hydrophobic and oleophilic and therefore easily floats and separates from the aqueous phase to provide immediate water washing and high coal recovery. do. The suspended hydrophobic coal is also easily separable from the aqueous phase (eg, a skim screen may be used for separation), which contains ash, sulfur, and other impurities separated from the coal. Although it is not completely understood and we do not wish to be bound by any theory, the surface treatment polymerization reaction produces a polymeric organic coating on the surface of the coal by molecular grafting of polymeric side chains onto the coal molecules. This seems to include the formation of. In the practice of the present invention, the surface-treated coal is preferably subjected to at least one further water washing step in which the coal phase is re-slurried into fresh washing water using good agitation, e.g. a high speed mixer. distributed. Preferably, the initially surface-treated coal is added to the wash water under atomizing pressure through a spray nozzle, which forms fine droplets in the air that are forced onto the surface and into the new water mass. Ru. In this way, some air is mixed into the system. By spraying, the wash water and treated coal phase are intimately mixed under superatmospheric pressure and under high speed agitation and/or shearing by the spray nozzle. In this way, hydrophobic coal particles are ejected into intimate contact with the wash water by one or more orifices of the spray nozzle, thereby causing passages in the nozzle and onto and into the air-water surfaces of the wash bath. induces air entrapment upon impact. U.S. Pat. A method and apparatus is disclosed in which a coal foam phase is formed by spraying or injecting a treated coal-water slurry onto the surface of the wash water. In summary, according to the method and apparatus described therein, a coal slurry is passed through at least one selected spray nozzle, preferably a hollow conical nozzle, at a pressure of about 15 to 20 psig, for example, at a spaced distance above the water surface. It is injected onto the surface of the water to create aeration and foaming or foaming of the stones, which causes these particles to float to the surface of the water for skimming. Said washing may be carried out on the treated coal slurry in the mere presence of water, for example at a temperature of about 10-90° C., with about 99-65% water by weight based on the weight of the dry coal feed. can. Alternatively, additional amounts of any or all of the surface treatment components described above, ie, polymerizable monomers, catalysts, initiators, and liquid organic carriers, may be added to the wash water. Furthermore, the cleaning conditions used when using these components, such as temperature, contact time, etc., are the same as when only water is present, and the cleaning conditions are the same as those described above for surface treatment of coal with a surface treatment mixture. can be the same as Of course, water conditioning additives may be used during the washing process if desired. After washing and/or additional surface treatment, the beneficent coal may be dried to a lower moisture concentration by mechanical means such as centrifugation, pressure or vacuum filtration, thereby reducing the cost of removing residual water. Eliminates the need for costly thermal energy. As mentioned above, the beneficiary coal produced by the method of the present invention generally contains about 0.5 to 10.0% by weight based on the dry coal weight.
Contains ash. Further, the sulfur content is about 0.1 to 4% by weight, preferably about 0.3 to 2% by weight, based on the weight of the dry coal, and the water content is about 2 to 25% by weight, based on the weight of the dry coal. Preferably it is about 2-15% by weight. In this regard, the beneficent coal has high energy content, ash and sulfur reduction, and can be used as a fuel product. This beneficiary fuel product can be used in direct combustion burner equipment. Alternatively, the beneficiary granular coal may be mixed with a carrier such as oil to provide a highly stable beneficent coal slurry such as a coal-oil mixture (COM). An oil, preferably a fuel oil such as No. 2 or No. 6, is mixed with the beneficiary coal in the desired ratio. These ratios are typically approximately
It contains 0.5-1.5 parts by weight to 1 part oil. 1:1
Preference is given to using weight ratios. It is also clear that the solid beneficiary coal products of the present invention can also be redispersed into aqueous systems for pumping into pipelines. If desired, it is preferred to add selected metal ions in their hydroxides or oxides to the aqueous dispersion to adjust the pH of the slurry to 7 or higher to improve stability. It is therefore possible to use hydroxides or oxides of alkali and/or alkaline earth metals, such as sodium, potassium, calcium, magnesium, etc., for this purpose. Sodium hydroxide is preferred. Also, the stabilized coal-oil mixture is

Due to the presence therein of an alkali or alkaline earth metal (e.g. sodium, potassium, calcium, magnesium, etc.) salt of a fatty acid of formula It has now been found that the unsaturated fatty acids, viz.

Also contemplated for use in the present invention is the formula: where R' is hydrogen and R is as defined above. The presence of the fatty acid salts in the beneficiary coal-oil mixtures of the present invention allows immediate dispersion of the coal into the fuel, producing gels or other structures that retard sedimentation almost indefinitely. In addition to alkali or alkaline earth metals, other metal ions are also useful in forming stable fatty acid salts. These other metals include, for example, iron, zinc, aluminum, and the like. Generally, the amount of fatty acid used to form a stable coal-oil mixture is from 3.0 to 0.5% by weight, based on the total weight of the mixture. The amount of alkali or alkaline earth-containing compound used to form the gel is sufficient to neutralize a substantial portion of the fatty acids, so generally about 0.1% based on the total weight of the coal-oil mixture. ~1.0% by weight, typically ~0.1
It can vary up to 0.6% by weight. Preferably, for a 50:50 coal-oil mixture, the mixture contains 15% acid and
Add 0.3% by weight neutralizing compound. An alternative practice used herein to form a stable coal-oil mixture is to subject the coal-oil mixture to an additional surface treatment reaction, in which case an additional amount of beneficiary coal in the oil is added to the mixture. of polymerizable monomer and a polymerization catalyst. In this case, the polymerizable monomer is an unsaturated carboxylic acid, preferably tall oil, as described above, used in an amount of 3.0 to 0.5% by weight, preferably 1.5%, based on the total weight of the mixture. The polymerization catalyst may be any of those mentioned above, preferably cupric nitrate, preferably from 2.0 to 10 ppm based on the total weight of the mixture.
Use in an amount of 5ppm. The polymerizable monomer and polymerization catalyst are added to the coal-oil mixture with stirring. Then, based on the total weight of the mixture, 0.6~
An alkali or alkaline earth compound such as sodium hydroxide is added to the mixture in an amount of 0.1% by weight, preferably 0.3%. The resulting product is a suitable stabilized coal-oil mixture. Other suitable methods for producing stable beneficent coal-oil mixtures are disclosed in U.S. Patent Application Nos. 230,055 and 230,064, filed January 29, 1981. For more information, see U.S. Patent Application No.
No. 230055 discloses the preparation of stable coal-oil mixtures by mixing beneficent coal with fatty acid esters such as triglycerides, preferably tallow, and bases such as sodium hydroxide. In summary, U.S. patent application Ser. A method of making a stabilized coal-oil mixture by subjecting it to shear agitation conditions is disclosed. The resulting coal-oil mixture is treated with a gelling agent, such as a hydroxide such as sodium hydroxide, to form a stable beneficent coal-oil mixture in the form of a gel or thixotropic mixture. The coal fuel oil product, or coal-oil mixture, of the present invention has unique properties. For example, the coal-oil mixtures of the present invention are thixotropic, have increased energy content, can utilize coal and a variety of coals with low ash, low sulfur and moisture content, and can be used extensively as liquid fuels. It offers the potential for an expanded market and thus can help preserve oil. Next, the present invention will be specifically described with reference to the accompanying drawings. With reference to the accompanying FIG. 1, the method of the present invention comprises:
For example, it is specifically carried out by first comminution of raw mined coal in comminution zone 10 in the presence of water and optional water conditioning additives to form an aqueous coal slurry. This aqueous coal slurry is passed through pipe 6 from tanks 1, 2, 3 and 4 via pipe 6 to pipe 6.
The coal slurry thus treated is introduced into beneficiation zone 12 as shown. Tanks 1, 2, 3 and 4 contain, for example, polymerizable monomer, free radical catalyst, free radical initiator and liquid organic carrier, respectively. Mined raw coal is fed into zone 10 via pipe 23, water is fed via pipe 21 and water conditioning additives can be introduced via pipe 25. Unwanted material, such as rock, is removed via pipe 27. Generally, water is the main component of beneficiation zone 12. The treated coal-slurry fed via pipe 6 to zone 12 is now hydrophobic and oleophilic and, after being mixed with the wash water in zone 12, for example by a high speed mixer or a spray atomizer,
It easily floats on the surface of the water, thereby forming a coal froth phase and an aqueous phase in zone 12.
The coal foam phase in zone 12 is transferred to zone 12 by pipe 47.
A beneficent or refined coal product according to the present invention is provided that is easily removed from the coal (e.g., by skimming or skimming) and has reduced ash, sulfur and water content. If desired, the refined coal from tube 47 can be further dried to remove additional water. The aqueous phase remaining in zone 12 contains ash, sulfur and other lipophilic impurities and is
1 can be removed. Alternatively, in carrying out the method of the invention according to FIG.
Additives can also be mixed directly with the aqueous coal slurry in the beneficiation zone 12. These reagents and/or additives are then placed in tubes 31 (monomer), 33
(free radical catalyst), 35 (free radical initiator), 37 (water), 39 (liquid organic carrier). The coal slurry is fed to zone 12 by tube 6 and is thus mixed with the reagents there. As previously mentioned, surface treating additives can alternatively be added to the coal spray coming from tube 6. With particular reference to the accompanying Figure 2, the process of the present invention is specifically carried out sequentially starting with the mined raw coal and ending with the coal-oil mixture, but otherwise as previously indicated. Feedstocks and products such as beneficiary granular coal and coal-water mixtures are also contemplated by the present invention. That is, referring to FIG. 2, raw coal is first milled in milling zone 10A in the presence of water and optional water conditioning additives to form an aqueous coal slurry. This aqueous coal slurry is fed via line 9 to mixing zone 11 where it is mixed with surface treatment reagents and additives sent via line 8 from reagent and/or additive tanks 1A, 2A and 3A and 4A. be done.
Tanks 1A, 2A, 3A and 4A each contain, for example, a polymerizable monomer, a free radical catalyst, a free radical initiator and a liquid organic carrier. Mined raw coal is fed to zone 10A via tube 23A, water is fed via tube 21A, and water conditioning additives are introduced to zone 10A via tube 25A. The resulting mixture in mixing zone 11 containing the initial chemically treated hydrophobic and oleophilic coal is then introduced via pipe 29 into first beneficiation zone 12A. Alternatively, surface treating additives (or additional surface treating additives), i.e., polymerizable monomers, polymerization catalysts, liquid organic carriers, as described below, such as tubes 31A (monomer), 33A (free radical catalyst), 35A (free radical initiator), 37A
(water), zone 12A via 39A (liquid organic carrier)
They can be added directly to [or zones 14 and 16] or they can be premixed with the pulverized coal slurry in tubes leading to the beneficiation zone or in vessels in the zone. If the surface treatment reagents/additives are added directly to zone 12A, the coal slurry is transferred from zone 10A to zone 12 via tubes 9A and 29.
It may be added directly to A. In addition, as previously mentioned, the coal slurry in the beneficiation vessels can be recycled into each special vessel for greater mixing and separation. The coal in zone 12A is highly hydrophobic and lipophilic, and agitation, for example in high speed mixers and spray atomizers, results in a coal foam phase that is collected. Screens can advantageously be used to separate and collect agglomerated coal. If desired, the harvested coal can be introduced via pipes 47 and 49 into a further washing step [e.g. coal foaming phase [zone 12A
Additional ash is released into the aqueous phase by further agitation. The water-wet ash suspended phase formed in zone 12A can be recovered and sent to wastewater and water recovery, and the water can then be recycled for reuse in a manner as shown in FIG. can. Alternatively, as noted in the preamble, additional ash and sulfur are removed from the beneficent coal foam phase by a series of countercurrent water-washing steps. That is, the aqueous phase in wash zones 14 and 16 can be recycled to the previous wash zone as also specifically shown in FIG. As indicated in the preamble, in addition to water, zones 12A, 14, and 16 may also contain any or all of the chemical surface treatment additives described above. The final washed and surface-treated coal leaving zone 16 via pipe 57 can be dried to a very low moisture concentration, for example by centrifugation. The water removed by centrifugation can be recycled to the process as shown. The harvested dry beneficiary coal product can itself be used directly as a solid fuel or can be combined with a carrier to form a highly desirable beneficent coal slurry, such as a coal-oil-liquid fuel mixture. In the production of coal-oil mixtures, according to FIG.

An acid such as tall oil or naphthenic acid may be added with an alkali metal hydroxide such as sodium hydroxide or calcium hydroxide to form a stable dispersion. If desired, the coal can be further surface treated in a coal-oil dispersion mixer by adding polymerizable monomers and polymerization catalysts to the mixture as described above (note that the previous addition is followed by alkali or alkaline earth water). with or without added oxides). Specifically, coal-
Fuel dispersion can be carried out continuously or batchwise, for example in conventional paint grinding equipment;
In this case, a low weight grinding medium is used to shear the dispersion into a non-sedimentable, flowable coal-fuel product with thixotropic properties. The coal-oil blending method (specifically shown in the main text) uses coal that has been beneficent as described in the main text, but any coal that has been beneficent by a method not described in the main text, such as raw coal, can be used. It goes without saying that a stable coal-oil mixture can be formed according to the method of the present invention. FIG. 3 specifically shows still another preferred embodiment in which the present invention can be achieved. Referring specifically to FIG. 3, raw coal is introduced via pipe 103 into the milling zone 70 and is milled in the presence of water added via pipe 101. The water preferably contains conditioning or processing additives such as inorganic or organic surfactants, wetting agents, dispersants or the like which increase the effectiveness of the water. Typical organic surfactants (e.g. Triton X-100) are anionic;
Includes cationic and nonionic substances. Sodium pyrophosphate is a preferred additive for purposes of this invention. The regulating component can be supplied to zone 70 via tube 105, for example. The aqueous coal slurry in zone 70 is conveyed via pipe 81 to mixing zone 82 and tanks 1B, 2B, 3B and 4B containing polymerizable monomer, free radical catalyst, free radical initiator and liquid organic carrier, respectively. Mix with reagents/additives from The aqueous chemically treated hydrophobic and oleophilic slurry mixture formed in zone 82 is fed to first water wash zone 72 via pipe 107 and high shear nozzle D, thereby increasing the flow rate and shear force to the coal phase. It is believed that the flow is broken up into fine droplets, which in turn pass through the inner air surface in the scrubbing zone 72 and impinge downwardly on a continuous body of water in, for example, a containing tank, and It can spray violently. If desired, further surface treatment reagents and/or additives as defined in the preamble may be added, such as tubes 109 (polymerizable monomer), 111 (free radical catalyst), 113 (free radical initiator), 1
15 (water), 117 (liquid organic carrier) through zone 72 [and/or) zones 74 and 76]
can be added to. The resulting hydrophobic and oleophilic coal phase in zone 72 is preferably further fed to a series of washing zones via tube 47 as shown. Without intending to be limited to any theory or reaction mechanism, we believe it is useful to discuss the phenomena that are believed to provide some of the advantageous results achieved with the method of the present invention. That is, the high shear forces generated during mixing, for example at nozzle D, assist in breaking up the coal-oil-water flocs as the dispersed particles forcefully enter the surface of the water in the tank, thereby removing the coal from the gaps between the coal floes. It is believed that water wets and releases ash and other impurities. This breaks up the coal floes so that the trapped ash and other impurities are liberated, introduced into the aqueous phase and separated from the coal particles. The finely divided coal particles (the surface of which is here assumed to be surrounded by polymers and liquid organic carriers such as fuel oil) are now also absorbed (occlusion) into the atomized particles as a result of the shearing effect of the nozzle. It also contains air. The combination of surface treatment and absorbed air reduces the apparent density of the agglomerated coal and causes it to float on the surface of the water as a distinct coal foam phase. Therefore, coal particles have a lower density than water, repel water due to their increased hydrophobicity, and float rapidly on the surface of water. By means of the aforementioned techniques, not only is ash substantially removed from the treated coal product, but also the entrapped air and further hydrophobic and oleophilic coal surface are ultimately extracted from the total beneficiation, treated coal. This results in a significant increase in yield. It should be noted that the hydrophilic ash remains largely in the aqueous phase and tends to settle to the bottom of the tank due to gravity and is removed from zone 72 in an ash-water stream 119 from the base of the vessel. The small amount of fine coal that cannot be completely separated can be sent to a fine coal recovery zone along with the aqueous phase (removed ash-water stream) as shown in FIG. The recovered coal fines can be recycled to the aqueous coal slurry in zone 70 via pipe 123. The washing step carried out in zone 72 can be repeated using a counter-current washing system, whereby the more selective water is passed sequentially through tubes 47 and 49 to zones 74 and 76 as illustrated in FIG. Proceed with the state. Concomitantly, the clean wash water becomes progressively loaded with water-soluble and water-wet solid impurities that are extracted with the wash water. As mentioned above, zone 7 contains a small amount of granular coal.
The intimately mixed ash-water suspension from 2 is sent to a fine coal recovery zone 121 where the high ash-low moisture solids are recovered and removed from the process, while the fine coal is Recirculated as follows.
The wash water can be further treated at 125 to condition the recovered water before recycling. The purified water is recycled back to the original aqueous coal slurry or other replenishment as the entire process requires to balance material flows. As shown in FIG. 3, the coal foam phase produced in zones 72 and 74 can be introduced for further cleaning via nozzles E and F, respectively. In this way the coal particles are ground again. The velocity and high shear produced by nozzles E and F force the wash water once again into contact with any ash still remaining in the interstices of the coal floes to assist in releasing the ash into the aqueous phase with each wash step. band 72,
The aqueous phase in 74 and 76 suspends the aggregated coal-oil-air mass to the top of their respective tanks. The final coal froth phase in zone 76 is fed via tube 57 to a centrifuge for drying. This allows the beneficent clean coal phase to be significantly dried without the need for thermal energy, which is caused by large coal-oil surface water and physical occlusion in the coagulated dry coal recovered from the mechanical drying process. This seems to be due to a decrease in the attraction of water. Dry hydrophobic cleaned coal can be advantageously used in this respect as a reduced ash and sulfur solid fuel with high energy content, hereinafter referred to as Product I in the text. As previously discussed in other aspects of the invention, there is also provided a liquid fuel mixture that is readily pumpable as a liquid but has rheological qualities such that it forms a thixotropic liquid. A thixotropic liquid is a liquid that has a "structure" or has a tendency to become sticky or gel-like when left at rest, but when shear stresses are applied to the thixotropic liquid by agitation in the mixing and pumping process or by heating. The viscosity is lost and the "structure" or gel is noticeably and rapidly reduced. As shown in FIG. 3, in the practice of the present invention, dry beneficiation coal products I are mixed in a mixing tank with a large amount of fuel oil (specifically 1:1 by weight, and when the fuel oil is of heavy viscosity grade). (in some cases, it is particularly preferred to heat the mixture to reduce its viscosity) to form a fluid mixture that can be pumped. Alternatively, the fuel-oil-coal mixture in the mixing zone may be subjected to a further surface treatment step along the general reaction procedure used in the initial surface treatment beneficiation described above.
For this purpose, any of the polymerizable monomers defined in the preamble, such as tall oil, corn oil, etc., are used and a mixing zone is used together with any of the polymerization catalysts and/or initiators defined in the preamble. can be added to. Additionally, the aforementioned saturated carboxylic acids can be used alone or in combination with unsaturated acids, if desired. If a saturated acid is used alone, no initiator and catalyst need to be used.
Naphthenic acid is a specific example of a saturated acid that can be used. The surface-treated mixture of coal, fuel oil, and carboxylic acid is then substantially neutralized with a water-soluble alkali metal hydroxide, such as sodium hydroxide, calcium hydroxide, or mixtures thereof, as described above, to form a stable coal. An oil mixture can be formed.
A liquid cream coal-oil fuel mixture (product) with no tendency to settle is extracted to provide a flowable high energy source for a wide range of end uses. Alternatively, the beneficiary coal product can be slurried with water to provide a coal-water slurry or mixture. FIG. 4 illustrates a unit 55 suitable as a foam flotation vessel useful in any of the washing and/or beneficiation zones used in the process of the present invention. In this unit, an aqueous coal slurry, ie a mixture of coal, water and preferably surface treatment reagents/additives, is pumped through tube 29 and spray nozzle 61.
Spray into container. Additional surface treatment reagents/additives or any other desired ingredients are added to tube 3.
1, 33, 35, 37 and 39. In this vessel the petroleum foam can be skimmed from the main part of the vessel into a collector compartment and introduced into the next zone, for example via pipe 147. The water-ash phase in the main part of the vessel is removed, for example through pipe 41. In this text, any of the zones illustrated in FIGS. 1-3 shall include a single vessel or zone or any number of vessels or zones arranged in any suitable manner according to the practice of the invention as described in the text. You may do so. In order to enable those skilled in the art to better understand the implementation of the present invention, the following examples are provided for illustrative purposes only and are not intended to be limiting. Example 1 Pittsburg seam coal having an initial ash content of 6.2% and an initial sulfur content of 1.5%.
seam coal) to a size of 200 mesh using a ball mill grinding unit in the presence of 400 g of water. Transfer the coal to a mixing container. In the container containing coal, 0.05g of corn oil, 2.0g of #2 fuel oil,
Introduce 1.0 cc of a 5.0% aqueous solution of hydrogen peroxide and 2.0 cc of aqueous cupric nitrate. Stir the mixture for about 30 minutes for about 2 minutes.
Heat to ℃ and stir. Spray the resulting mixture into a container with clean water and ensure foaming. The coal in the coal foam phase is skimmed from the water phase. The aqueous phase containing large amounts of hydrophilic ash and sulfur is discarded. The cleaning operation is repeated two more times using clean water and a skim of foamed coal from the aqueous phase. The granular coal is then dried using a laboratory Buchner funnel to a moisture content of 15% based on dry coal weight. The ash content of the final granular product is reduced to 1.5% and the sulfur content is 0.8%
will be reduced to Example 2 Equal amounts of (a) each replaced with corn oil
Example 1 is repeated using coker gasoline, (b) oleic acid and (c) tall oil. A clean coal granular product is obtained having an ash content of about 3% and a moisture content of about 15%, based on the dry coal weight. Example 3 Substituting Pittsburgh seam coal with (a) Kittanning seam coal, (b) Illinois #6 seam coal, and (c) lower grade Freeport seam coal. The method of Example 1 was repeated. Approximately 3.0% ash content and 15% based on dry coal weight
A clean coal product is obtained with a moisture content of %. Example 4 200 g of Illinois #6 coal (19.9% ash content) reduced to approximately 1/4″ size chunks was crushed to a particle size of approximately 28 mesh and then reduced to 200 mesh in a laboratory ball mill in the presence of water. Pulverize to form a coal-water-based liquid slurry. The liquid phase of the slurry contains approximately 65% water based on the total weight of the slurry. 50 mg tall oil, 10 g fuel oil, 250 mg sodium pyrophosphate. , 100 mg of cupric nitrate, and ₁₀ of _H2O2
mg (5% aqueous solution) is added to the above coal-water slurry at about 30-40°C. the resulting hydrophobicity,
The surface-treated coal phase is collected by removing it from the surface of the aqueous phase in which it is suspended. The aqueous phase contains hydrophilic ash and is discarded. The surface-treated coal is harvested after several redispersions in clean soft water containing sodium pyrophosphate at approximately 30 °C. After passing through the Buchner funnel, the water content of the coal is approximately 15%. (Coal without conventional processing, i.e., chemical surface treatment, usually retains about 20-50% moisture when ground to the same mesh size.) Mix with 160g of fuel oil and add another 5.0g of tall oil. After thorough mixing at 85°C, add caustic soda equivalent to the acid value of the mixture and mix further. No sedimentation of the coal-liquid fuel mixture was observed after being left for several months. Example 5 Example 4 with gram equivalents of the following polymerizable monomers:
The method of Example 4 is repeated except that the tall oil used in Example 4 is replaced. (a) Coker gasoline and (b) oleic acid. When the surface of pulverized coal was modified in the same way, strongly hydrophobic coal particles were obtained, and these were used in Example 4.
Process in the same way as . In each case, after drying, the same amount of tall oil is mixed with the harvested beneficiation coal. The acidity is neutralized with caustic alkali and a similar coal-oil liquid suspension is prepared, both based on the selected metal ion to replace the sodium ion of the initially added sodium hydroxide. Shows thixotropic properties. Regardless of the monomer used in the surface treatment reaction, no sedimentation is observed even after several weeks of observation. Example 6 The procedure of Example 4 is repeated, except that 2 g of benzoyl peroxide is used instead of hydrogen peroxide. Additionally, 2 g of Triton-X-100 surfactant and 25 g of sodium pyrophosphate are present in the initial slurry water. The ash in the resulting aqueous phase is removed after treatment with lime. The ash content of the treated coal ranges from about 19.9% after five separate washes to about
reduced to 4.7%, where water is Triton-X-100
and sodium pyrophosphate. The tall oil used in the surface treatment reaction and the tall oil used to form the stable coal-oil mixture is first neutralized with caustic soda and then treated with an equal amount of calcium hydroxide. The viscosity of the coal-oil mixture is thixotropic gel-like in nature, indicating that no sedimentation is observed even after long periods of standing. Example 7 235 g of beneficiation coal with 15% moisture content produced according to Example 1 is placed in a container where the coal is supplemented with 200 g of #2 fuel oil, 6.0 g _of tall oil, 0.1% _H2O2
(or benzoyl peroxide) in water (toluene) solution
A stabilized coal-fuel oil mixture is formed by adding 1.0 g and 2.0 g of cupric nitrate 0.1% aqueous solution. Stir the mixture at about 85°C for about 1.0 minute. Add 1.5g of sodium hydroxide and approx. 65℃
Stir for 5.0 minutes. The resulting coal-oil mixture is a stabilized gel and remains this way indefinitely. Of course, other modifications and variations of the present invention are possible in light of the above teachings. Therefore,
It is clear that changes may be made to the particular embodiments of the invention and these are within the scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a flow diagram illustrating the method of the present invention for beneficiation of solid carbonaceous materials, such as coal.
FIG. 2 is a flow diagram illustrating a preferred mode of beneficiation of solid carbonaceous materials, such as coal, in accordance with the present invention. FIG. 3 is another flow diagram illustrating another preferred manner of carrying out the invention.
FIG. 4 is an illustration of a typical container used in the practice of the present invention.

Claims (1)

[Claims] 1. Mixing coal in an aqueous medium with a surface treatment mixture consisting of a polymerizable monomer, a polymerization catalyst, and a liquid organic carrier, thereby imparting hydrophobic and lipophilic properties to the coal. A coal beneficiation method characterized by: 2. A patent further comprising subjecting the surface-treated hydrophobic, oleophilic coal to at least one water wash to remove selected amounts of impurities, and collecting the resulting beneficiation coal product. The method according to claim 1. 3. The method according to claim 1 or 2, wherein the liquid organic carrier is a non-fuel oil liquid organic carrier. 4. The liquid organic carrier is benzene, toluene, xylene, naphtha and medium boiling point petroleum fraction,
Any one of claims 1 to 3 selected from the group consisting of dimethylformamide, tetrahydrofuran, tetrahydrofurfuryl alcohol, dimethyl sulfoxide, methanol, ethanol, isopropyl alcohol, acetone, methyl ethyl ketone, ethyl acetate, and mixtures thereof. The method described in. 5. The surface-treated hydrophobic, lipophilic coal is subjected to at least one water wash by subjecting the chemically treated coal to high shear mixing with at least one aqueous washing medium. Range 2nd to 4th
The method described in any of the paragraphs. 6. The method of claim 5, wherein the high shear mixing of the chemically treated coal and the aqueous cleaning medium is carried out by injecting the coal into the aqueous cleaning medium under spray pressure through a spray nozzle. Method. 7. Free radical initiation, wherein the polymerizable monomer is selected from tall oil, corn oil or mixtures thereof, and the polymerization catalyst is selected from free radical catalysts and inorganic water-soluble metal salts, organic metal salts or mixtures thereof. and wherein the metal is selected from iron, zinc, antimony, arsenic, copper, tin, cadmium, silver, gold, platinum, chromium, mercury, aluminium, cobalt, nickel or lead. The method described in any one of Items 1 to 6. 8 The polymerizable monomer is corn oil,
8. A process according to any of claims 1 to 7, wherein the catalyst is hydrogen peroxide and the free radical initiator is cupric nitrate. 9. A monomer that can be polymerized by at least one washing with water,
9. A process according to any one of claims 2 to 8, which is carried out in the presence of a member selected from a polymerization catalyst, a liquid organic carrier or a mixture thereof. 10. The method according to claim 1 or 2, wherein the polymerization catalyst is selected from the group consisting of anionic catalysts and cationic catalysts. 11. A beneficent coal product consisting of surface-treated hydrophobic and oleophilic coal having a reduced ash content in the range of about 0.5-10% by weight based on the weight of the dry coal. 12. The coal product of claim 11, wherein the beneficent coal product is present in intimate admixture with fuel oil. 13. The coal product of claim 11, wherein the beneficiary coal product is present in a mixture with a carrier. 14. The coal slurry according to claim 13, wherein the carrier is water. 15 Coal characterized in that finely ground coal is admixed with a member selected from polymerizable monomers, saturated aliphatic carboxylic acids or mixtures thereof and alkali or alkaline earth hydroxides in the presence of fuel oil. Method for producing oil mixtures. 16 the polymerizable monomer is tall oil,
16. The method of claim 15, wherein said hydroxide is selected from the group consisting of sodium hydroxide and calcium hydroxide. 17. A process for producing a coal-oil mixture, characterized in that pulverized coal is mixed with a polymerizable monomer and a polymerization catalyst in the presence of fuel oil. 18. Mixing pulverized coal with polymerizable monomers and polymerization catalysts in the presence of fuel oil to form a coal-oil mixture, and then stabilizing the coal-oil mixture by introducing hydroxide. 1. A method for producing a coal-oil mixture, comprising: forming a coal-oil mixture that is 19 The polymerizable monomer is tall oil,
Claim 1, wherein said polymerization catalyst comprises a mixture of a free radical catalyst and a free radical initiator, and said hydroxide is sodium hydroxide.
The method described in Section 8. 20. The method of claim 19, wherein the free radical catalyst is hydrogen peroxide and the free radical initiator is cupric nitrate. 21 A beneficent coal product consisting of a surface-treated hydrophobic and oleophilic coal having a reduced ash content in the range of about 0.5 to 10% by weight based on the weight of the dry coal, water and an aqueous coal mixture at pH 7. A stabilized aqueous coal mixture consisting of an intimate mixture of an alkali or alkaline earth metal hydroxide or oxide in an amount sufficient to 22. The mixture according to claim 21, wherein the alkali hydroxide is sodium hydroxide. 23. Claim 17, wherein the polymerization catalyst is selected from anionic catalysts and cationic catalysts.
The method described in section. 24 Coal pulverizing means; means for supplying pulverized coal from said coal pulverizing means to a surface treatment reaction zone; means for introducing a measured amount of a chemical reactant for surface treatment of said coal in an aqueous medium; a surface treatment reaction zone; a means for introducing the surface treated coal from said surface treatment reaction zone into a water washing zone; and at least one means for incorporating the introduced or contained components under high shear agitation. Apparatus for producing a beneficiary coal product characterized by a continuous combination of water washing zones.