Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10L—FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
  • C10L1/00—Liquid carbonaceous fuels
  • C10L1/32—Liquid carbonaceous fuels consisting of coal-oil suspensions or aqueous emulsions or oil emulsions
  • C10L1/326—Coal-water suspensions

Definitions

• This invention relates to a high consistency aqueous slurry of powdered coal which may be conveyed by a hydraulic pump and is combustible as such.
• a high consistency aqueous slurry of powdered coal capable of conveying by a hydraulic pump and combusting as such.
• the slurry contains, as a viscosity lowering agent an effective amount of a polyether compound selected from the group consisting of:
• the viscosity lowering agents used herein may be prepared by first synthesizing the compound a) and then optionally converting the same into compounds b) or c).
• the compound a) typically has the formula: wherein Z is the residue of an active hydrogen compound, RO is a C 3 or C 4 oxyalkylene unit, n and m each represents a recurring number, and x is the number of oxyalkylene chain bonded to the residue Z.
• the above polyether compound may be prepared in per se known manner by reacting a starting active hydrogen compound with ethylene oxide and optionally with a C 3 -C 4 alkylene oxide, epichlorhydrine or ethylene carbonate under elevated pressures in the presence of an acid or alkaline catalyst. Where two or more different alkylene oxides are combined, the resulting copolymer may be either a block or random copolymer. However, the copolymer must contain at least 10% by weight of oxyethylene unit based on the total oxyalkylene chain content. The molar ratio of alkylene oxide to the starting active hydrogen compound is adjusted such that the resulting adduct has a molecular weight of at least 1,000, preferably from 1,000 to 600,000.
• the active hydrogen compound used herein must have at least one hydrogen-containing, functional group such as hydroxyl, amino, imino, and carboxylic groups.
• hydroxyl group-containing compounds include water; monohydric alcohols such as ethanol, butanol, octanol, cyclohexanol and benzyl alcohol; dihydric alcohols such as ethylene glycohol, polyethylene glycol, propylene glycol, polypropylene glycol, butanediol, pentanediol and hexanediol; trihydric alcohols such as glycerine, butanetriol, hexanetriol, trimethylolpropane and triethanolamine; tetrahydric alcohols such as diglycerine and pentaerythritol; those having five or more hydroxyl groups such as xylitol, sorbitol, glucose, sucrose, partially saponified products of vinyl acetate polymers or copolymers, cellulose and starch; and the like.
• monohydric alcohols such as ethanol, butanol, octanol, cyclohex
• Aromatic hydroxyl compounds may also be used as a starting active hydrogen compound. Examples thereof include monophenols such as phenol, cresol, xylenol, butylphenol, nonylphenol, aminophenol and hydroxybenzoic acid; polyphenols such as catechol, resorcine and pyrogallol; mono- and polynaphthols such as naphtol, methylnaphthol, butylnaphthol, octylnaphthol, naphthoresorcine and a-naphthohydrequinone; bisphenols such as bisphenol A and bisphenol S; condensates of these aromatic hydroxyl compounds with an aliphatic aldehyde such as formaldehyde, acetaldehyde or glyoxal; and the like.
• monophenols such as phenol, cresol, xylenol, butylphenol, nonylphenol, aminophenol and hydroxybenzoic
• amino or imino group-containing compounds include secondary amines such as dimethylamine and N-methyllaurylamine; primary amines such as methylamine, ethylamine, propylamine, butylamine, allylamine, amylamine, octylamine, dodecylamine, laurylamine, tetradecylamine, pentadecylamine, octadecylamine, tallow alkylamine, coconut alkylamine, aniline, p-toluidine, m-toluidine, nitroaniline, benzylamine, chloraniline, p-dodecylbenzylamine and cyclohexylamine; amines having three active hydrogen atoms such as ammonia and tallow propylenediamine; amines having four active hydrogen atoms such as urea, ethylenediamine, tetramethylenediamine, hexamethylenediamine, phen
• carboxylic acids examples include monocarboxylic acids such as acetic acid and lauric acid; dicarboxylic acids such as oxalic acid, fumaric acid and maleic acid; tri- or higher carboxylic acids such as trimesic acid, butanetetracarboxylic acid, and pyromellitic acid; and the like.
• Compounds having two or more different active hydrogen-containing functional groups such as lactic acid, glycolic acid, glycine, N-monoalkylglycine, malic acid, tartaric acid, monoethanolamine, diethanolamine and aminoethylethanolamine may also be used as a starting active hydrogen compound.
• the average molecular weight of the resulting polyether may be easily estimated by determing the hydroxyl number thereof.
• the polyether compounds of the above class a) have at least one free hydroxyl group at the terminal of oxyalkylene chain. This hydroxyl group may be entirely or partially reacted with an appropriate acylating agent to obtain the corresponding inorganic or organic ester.
• inorganic acylating agents include sulfuric acid, chlorosufonic acid, sulfamic acid and sodium bisulfite for sulfate esters, and phosphorus pentoxide, metaphosphoric acid and thiophosphates for phosphate esters.
• These esters may take the form of an free acid or salt with a metal such as sodium, potassium, calcium and magnesium, or other cations such as ammonia, organic amines and quaternary ammonium ions.
• the hydroxyl group of compound a) may be modified by per se known reaction to obtain the corresponding ester with inorganic or organic acid, halide such as chloride or bromide, aldehyde, carboxylic acid and urethane.
• halide such as chloride or bromide, aldehyde, carboxylic acid and urethane.
• Cross-linked polyether compound b) may be prepared by reacting a polyether compound a) mentioned-above with a . cross-linking agent.
• cross-linking agents may be employed for this purpose and include polyisocyanates such as hexamethylene diisocyanate, tolylene diisocyante, xylylene diisocyanate, 1,5-naphthylene diisocyanate and 4,4'-diphenylmethane diisocyanate; polyepoxy compounds such as diglycidyl bisphenol A, diglycidyl ethylene glycol and diglycidyl tetraoxyethylene glycol; polycarboxylic acids and their functional derivatives (e.g.
• anhydrides and halides such as oxalic acid, malonic acid, phthalic acid, maleic acid, glutaric acid, adipic acid, azelaic acid, sebatic acid, dodecanedioic acid, dimer acid, hemimellitic acid, trimellitic acid, butanetetracarboxylic acid, pyromellitic acid, ethylenediamine tetraacetic acid, polymers and copolymers of acrylic acid, polymers and copolymers of methacrylic acid, polymers and copolymers of maleic anhydride, partially saponified polymers and copolymers of acrylates or methacrylates; and fuctional derivatives (e.g.
• anhydride or halides of these acids
• polyaldehyde such as glyoxal and succinal- dehyde
• peroxides free radical generating catalysts
• hydrogen peroxide benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide and dicumyl peroxide
• formaldehyde in combination with acid catalysts.
• the above polyisocyanate or polyepoxide cross-linking agnets When the above polyisocyanate or polyepoxide cross-linking agnets are used, they may be added in 0.05 to 5, preferably 0.1 to 3 equivalents per equivalent of terminal hydroxyl group present in the polyoxyalkylene chain of the polyether compound a).
• the reaction may be carried out by heating the reaction components at a temperature of 40 to 150°C, preferably 50 to 120°C optionally in the presence of a conventional acid or alkali catalyst.
• Polycarboxylic acids or their derivatives may be used in 0.05 to 5, preferably 0.1 to 3 equivalents per equivalent of said hydroxyl group.
• the reaction may be carried out at a temperature of 60 to 250°C, preferably 80 to 220°C optionally in the presence of a conventional esterifying catalyst.
• the reaction temperature may be lowered to -10 to 150°C, preferably 0 to 120°C with blowing an inert gas into the reaction mixture or in the presence of an acid acceptor.
• polyethers a) may be reacted with 0.05 to 10% by weight, preferably 0.1 to 5% by weight of a peroxide catalyst at a temperature of 50 to 250°C, preferably 70 to 180°C optionally in an inert solvent.
• the resulting cross-linked polyethers b) may be converted into their derivatives c) by modifying the residual hydroxyl group by per se known reactions.
• Said derivatives include esters with inorganic or organic acids, halides such as chlorides and bromides, corresponding.aldehydes or carboxylic acids, and urethanes with monoisocyanates.
• coal may be used for preparing the aqueous slurry of powdered coal of the present invention and include anthracite, bituminous coal, subbituminous coal, lignite and cleaned coal of these types.
• cleaned coal refers to those products obtained from mined coal by removing or decreasing its inorganic impurity contents such as ash and sulfur.
• processes are known for cleaning coal in this manner such as the heavy media separation process, the oil agglomeration process, the floatation process and other processes. Any process may be applied for preparing cleaned coal used in the present invention.
• the oil agglomeration process may be carried out by adding an amount of oil to an aqueous slurry of pulverized coal particles or suspending oil-coated pulverized coal particles in water, and then stirring the slurry.
• Organic components in the coal are wetted selectively with oil to agglomerate into a mass, while inorganic impurities thereof remain in the aqueous phase. Separation of aqueous phase from the mixture gives cleaned coal having a greatly reduced inorganic impurity content.
• the process is generally carried out at a coal concentration from 10 to 65%.
• oils which may be used in the oil agglomeration process include petroleum crude oil and liquid ' fractions thereof such as kerosine, light oil, bunker A, bunker B, bunker C and the like.
• Other mineral oils such as residue from ethylene-cracking, shale oil, lubricant oil and cleaning oil as well as benzene, toluene, xylene and various animal and vegetable oils may be used.
• Heavy oils such as bunker C or tar residue oil are preferable for economical reason.
• the amount of oil needed for giving a satisfactory result is generally less than 20% by weight based on the weight of coal.
• the floatation process may be carried out, as is well-known, by adding a very small amount of oil into a pluverized coal-water slurry and then vigorously stirring the slurry to form froth.
• Oil which may be employed in the floatation process include terpene oil, tar, bunker A, bunker C, light oil and kerosine.
• the above two processes may generally reduce the inorganic impurities by several tens percents of their original contents.
• the use of cleaned coal in the composition of this invention has an important advantage that the viscosity lowering agent used herein is more effective to cleaned coal than to uncleaned coal thereby allowing the preparation of slurries having several points higher consistencies than when uncleaned coal is employed. Additionally, damages to boilers and loads to desulfuring and ash disposal equipments are greatly decreased.
• the particle size of powdered coal used herein complies with the requirements by various users such as power plants and is such that at least 70% of the particles can pass through a standard 200 mesh screen.
• the viscosity lowering agent used in the present invention may remarkably decrease the viscosity and impart fluidity to aqueous slurries of powdered coal which are otherwise too viscous to be conveyed by pumping. Normally, simple aqueous slurries of powdered coal will lose fluidity completely at a consistency of 50% or higher.
• the aqueous slurry of the present invention may have a consistency higher than 60%, preferably 70% by weight while retaining sufficient fluidity to be conveyed by pumping. When cleaned coal is used, the consistency may be further increased by 3 to 10 points.
• the amount of viscosity lowering agent needed for achieving satisfactory results lies generally from 0.01 to 5.0%, preferably from 0.03% to 2.0% by weight based on the entire composition.
• the viscosity lowering agent used in the present invention is strongly . adsorbed by coal particles on their surfaces because of their unique structure and then hydrated with surrounding water molecules. This results in the formation of lubricant configuration of water molecules surroung coal particles, retaining coal particles as stable primary particles, increase in fluidity and decrease in viscosity.
• cleaned coal can be fluidized more effectively with the viscosity lowering agent because of its increased organic nature due to the removal of hydrophilic, fine ash components.
• the viscosity lowering agent used in the present invention may stabilize the aqueous slurry of powdered coal and prevent coal particles from sedimentating upon stationary standing for a long period of time, e.g. for one month.
• coal blockes may be disintegrated in the dry process and the powdered coal may be mixed with water containing the viscosity lowering agent.
• coal may be disintegrated in a mill by the wet process in the presence of water and the viscosity lowering agent.
• aqueous slurries as shown in Table 2 were prepared from powdered coal pulverized to 80% passing through a 200 mesh screen. The viscosities and fluidities of the resultant slurries were determined at 25°C, respectively.
• the slurries were poured into a cylinder up to 18 cm level and allowed to stand for one month. Thereafter, the consistencies at upper layer (up to 1 cm below the top level) and lower layer (up to 1 cm above the bottom) respectively were determined.
• the aqueous slurries of the present invention have a viscosity ranging from 800 to 2,800 cps and retain a sufficient fluidity for pumping transportation at a powdered coal consistency ranging from 72 to 77%. It is also noted from Table 2 that the slurries of the present invention are stable upon storage and no or little sedimentation of coal particles occurs upon standing for at least one month.
• control slurries in which no or conventional surfacts are added have a viscosity higher than 20,000 cps and exhibit almost no fluidity even at a coal consistency of 50%.
• Example 1 The procedure of Example 1 was repeated except that cleaned powdered coal was used. Formulations and results obtained were shown in Table 3.
• the slurries have a viscosity ranging from 1,000 to 2,800 cps and retain a sufficient fluidity for pumping transportation at a coal consistency ranging from 76 to 80%, while control samples exhibit a viscosity higher than 20,000 cps and no fluidity even at a coal consistency of 50%.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Detergent Compositions (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)

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Cited By (10)

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• 1982
  • 1982-09-13 CA CA000411263A patent/CA1180555A/en not_active Expired
  • 1982-09-13 EP EP19820108435 patent/EP0077909B2/de not_active Expired
  • 1982-09-13 DE DE8282108435T patent/DE3270436D1/de not_active Expired
  • 1982-09-13 ES ES515682A patent/ES8308918A1/es not_active Expired
  • 1982-09-13 AU AU88331/82A patent/AU553292B2/en not_active Ceased

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