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
  • C10L1/324—Dispersions containing coal, oil and water
• • 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

• the present invention relates to an aqueous slurry and to the related preparation processes.
• an aqueous coal slurry which contains two separate groups of coal particles, wherein the particles of the first group have an average size comprised within the range of from 210 to 60 ⁇ m, the maximum size being not greater than 300 ⁇ m, and the particles of the second group have a size comprised within the range of from 1/6th to 1/20th of those of the first group.
• a first object of the present invention is an aqueous coal slurry at a concentration comprised within the range of from 60% to 80% by weight, comprising a polyelectrolyte selected from the monovalent cation salts of the polymerized naphthalenesulphonic acids having a molecular weight comprised within the range of from 800 to 3,000, preferably around 2,000, characterized in that on coal surface, which coal is constituted by particles having a granulometry not greater than 300 ⁇ m, a liquid which is obtained by the distillation of pit-coal tar, or a fuel oil derived from mineral oil, is present, in an amount comprised within the range of from 0.1% to 2%, preferably of from 0.2% to 1.2%, by weight, relatively to same coal.
• the liquid obtained from the distillation of pit-­ coal tar is preferably selected from those having a distillation range comprised within 200 and 400°C, more preferably between 250 and 350°C.
• creosote oil can be used.
• the fuel oil deriving from mineral oil is selected from those having a viscosity at 50° preferably not lower than 3°E.
• Coal can be constituted by one single group of particles, or by two particle groups.
• the first group may contain particles having an average granulometry comprised within the range of from 210 to 60 ⁇ m, the maximum size being however not greater than 300 ⁇ m;
• the second group can contain particles having an average granulometry comprised within the range of from 1/6th to 1/20th of the average granulometry of the particles of the first group, by "average granulometry of the particles” the granulometry corresponding to 50% of the cumulative mass distribution of that group being meant.
• the particles of the first group should preferably be at least 40% of total, more preferably at least 60% by weight of total particles.
• the cumulative particle distribution curve by resulting from two fractions (i.e., two distinct groups of coal particles), should show, if reported on a bi­logarithmic scale (log-log chart), a flat zone comprised between the values of the average dimensions of component fractions; wherein by "flat zone” a length of the curve is meant, wherein the derivative, computed on a bilogarithmic scale (log-log chart), is lower than 0.4, and preferably lower than or equal to 0.1, and still more preferably equals zero.
• the cumulative granulometric distribution should hence be such that always two particle size values d1 and d2, comprised between the average values of the diameters of the two fractions exist, for which the numeric value of the following expression is lower than 0.4, preferably lower than or equal to 0.1, and, still more preferably, equals 0.
• (%CM1) and “(%CM2)” the values are indicated of the cumulative percentages of the mass of particles, respectively having a size lower than d1 and d2.
• the numerical value of the expression is, obviously, independent from the unit of measure (micrometres or millimetres) according to which the particle size is expressed.
• the addition of the liquid obtained by means of distillation of pit-coal tar is carried out during the same beneficiation treatment, by performing such a treatment in the presence of a light hydrocarbon of from 4 to 8, preferably from 5 to 6, carbon atoms, said hydrocarbon being flashed off after the agglomeration.
• n-­pentane and n-hexane we mention here n-­pentane and n-hexane.
• the Light hydrocarbon is preferably present in a percentage comprised within the range of from 5% to 30% by weight relatively to coal.
• a second object of the present invention is the process for preparation of the aqueous coal slurries.
• the process comprises a beneficiation by agglomeration in water of a coal having a granulometry not higher than 300 ⁇ m with a liquid obtained by means of the distillation of pit-coal tar, or with a fuel oil deriving from mineral oil, in an amount comprised within the range of from 0.2% to 2% by weight relatively to coal, and a light hydrocarbon comprising a number of carbon atoms comprised within the range of from 4 to 8, in an amoung ranging from 5% to 30% by weight relatively to coal, the flashing of the light hydrocarbon, after that the prevailingly organic portion has agglomerated and separated from the aqueous solution in which the inorganic components have remained suspended or dissolved, and, finally, the slurrying in an aqueous solution comprising a polyelectrolyte, as the dispersant, selected from the monovalent cation salts of polymerized naphthalenesulphonic acids having a molecular weight of from 800
• polyelectrolytes there can be used, e.g., the chemical compounds known under the tradename of DAXAD 15 and DAXAD 19 by W.R. Grace, and Reoplast 203 by Fratelli Lamberti S.p.A.
• the process comprises the slurrying of a coal having a granulometry not greater than 300 ⁇ m, in a solution containing a liquid obtained by means of the distillation of pit-coal tar, or a fuel oil deriving from mineral oil, in an amount comprised between 0,2% and 2% by weight relative to coal, and a light hydrocarbon liquid comprising a number of carbon atoms comprised within the range of from 4 to 8, in an amount comprised within the range of from 50% to 200% by weight relatively to coal, followed by the flashing of the light hydrocarbon and by the forma­tion of an aqueous slurry by means of the addition of a dispersant constituted by a polyelectrolite selected from the monovalent cation salts of polymerized naphthalenesulphonic acids having a molecular weight of from 800 to 3,000, preferably around 2,000, the percent amount of the dispersant being comprised within the range of from 0.05% to 0.5%
• the preferred liquids obtained from the distillation of pit-­coal tar the preferred fuel oils deriving from mineral oil, the preferred light oils, and the preferred polyelectrolytes, what above said for the aqueous slurries holds true as well.
• the coal having this granulometry was used for preparing the slurries after being coated with a creosote oil film.
• the coating by the creosote oil was achieved by diluting this latter oil in n-hexane, subsequenty adding coal, under stirring, and finally flashing off the solvent.
• the amount of creosote oil added to coal was 0.5% by weight based on dry coal, and the amount of n-hexane was 100% by weight.
• samples were then prepared and analysed of water-coal slurries, with a solids concentration of 62% by weight, to which 0.2% 0.3% and 0.5% by weight of DAXAD 15, relatively to the suspension, was added.
• the blend was characterized in terms of its apparent viscosity at 50 sec ⁇ 1.
• a Polish coal having the following analytical characteristics:
• the coal with the above described granulometry underwent a beneficiation treatment by selective agglomeration with n-pentane and creosote oil. Used amount of creosote oil equalled 0.5% by weight relatively to coal.
• the beneficiation step was carried out on a batch equipment having a capacity of 10 litres of slurry, on a coal slurry in water at 20% of solids by weight, by using a concentration of n-hexane of 20% relatively to dry coal.
• n-pentane was removed by drying under N2 in oven at 40°C.
• the induction times of the agglomeration phenomenon i.e., the times necessary for agglomeration to begin, resulted sharply shorter: from the 15-minute time of the test with n-pentane only, a decrease to the 8-minute time of the test with n-pentane plus creosote oil as the agglomerating agent were obtained, with obvious advantages from the viewpoint of process economy.
• n-pentane was removed by oven-drying under N2 at 40°C.
• Example 15 The same Polish coal as of Example 9-11, with the same bimodal granulometry, not beneficiated, and without creosote oil, was used to prepare slurries to which 0.2% (Example 15), 0.3% (Example 16) and 0.5% by weight (Example 17) of DAXAD had been added.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Dispersion Chemistry (AREA)
• Liquid Carbonaceous Fuels (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Carbon And Carbon Compounds (AREA)
• Medicinal Preparation (AREA)
• Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)

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• 1986
  • 1986-05-02 IT IT20295/86A patent/IT1189094B/it active
• 1987
  • 1987-04-23 DE DE8787200771T patent/DE3770867D1/de not_active Expired - Lifetime
  • 1987-04-23 AT AT87200771T patent/ATE64610T1/de not_active IP Right Cessation
  • 1987-04-23 EP EP87200771A patent/EP0244902B1/de not_active Expired - Lifetime
  • 1987-04-23 ES ES87200771T patent/ES2024490B3/es not_active Expired - Lifetime
  • 1987-04-24 ZA ZA872947A patent/ZA872947B/xx unknown
  • 1987-04-30 PL PL1987265442A patent/PL159184B1/pl unknown
  • 1987-04-30 RU SU874202470A patent/RU1838384C/ru active
  • 1987-05-01 CA CA000536153A patent/CA1328735C/en not_active Expired - Fee Related
  • 1987-05-01 AU AU72423/87A patent/AU599376B2/en not_active Ceased
  • 1987-05-01 JP JP62106483A patent/JPS62266313A/ja active Pending
• 1991
  • 1991-07-09 GR GR91400984T patent/GR3002281T3/el unknown

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