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 coal-aqueous mixtures containing heteric poly(oxyalkylene) nonionic surfactants as viscosity reducers.
• U.S. Patent 4,358,293 discloses coal-aqueous mixtures having high solids content.
• the solids are dispersed into the water by using selected poly(oxyalkylene) nonionic surfactants.
• the selected surfactants are block copolymers of ethylene oxide and propylene oxide derived from di- and higher functionality initiators.
• Particularly suitable for use in the invention were found to be block polymers of ethylene diamine and propylene oxide derived from nitrogen containing compositions such as ethylene diamine and having a molecular weight of at least 14,000, as described at column 3, lines 35-50 of the patent.
• the present application describes the composition of liquid additives which can be repidly dissolved in water and are as effective or more effective than the selected poly(oxyalkylene) nonionic surfactants mentioned in U.S. Patent 4,358,293 in reducing the viscosity of coal water mixtures.
• the subject invention relates to a coal-aqueous mixture comprising:
• the subject invention also relates to a process for preparing a coal-aqueous mixture comprising (a) mixing the neat viscosity reducer with water to produce homogeneous solutions containing from 5 to 50 percent of the viscosity reducer, (b) adding the above solution to a particulate coal in such a way that the ratio of coal to viscosity reducer is from 1000:1 to 10:1, and (c) blending, under vigorous agitation, the particulate coal with a sufficient amount of water to produce slurries with a coal load varying from 40 to 90 percent by weight of the total slurry.
• the viscosity reducer solution in (a) can be admixed with a water stream in such a way that the resulting ratio of water to viscosity reducer is from 1000:1 to 10:1, and this solution can then be blended under vigorous agitation with particulate coal in sufficient amount to produce slurries with a coal load varying from 40 to 90 percent by weight of the total slurry.
• the subject composition and process are particu­larly advantageous because the viscosity reducer is dis­solvable in water at ambient temperature in shorter time periods than comparable products shown in the prior art as subsequent data will show. This feature is important because the viscosity reducer is mixed with the water before the particulate coal is added. Uniform mixing of the viscosity reducer and water is important in obtaining uniform viscosity.
• the particulate coal used in the subject invention may be bituminous coal, anthracitic coal, sub-bituminous coal, lignitic coal, charcoal, and petroleum coke.
• the particle size of the particulate coal should range from 0.1 to 350 ⁇ m, preferably 1 to 250 ⁇ m. For best results, however, the particle size should not exceed about 200 ⁇ m.
• the amount of particulate coal used in the coal-water mixture generally will be from 40 to 90 percent by weight, preferably 70 to 80 percent by weight, based upon the total weight of coal-water mixture.
• the viscosity reducer which is liquid at ambient temperature is a heteric poly(oxyalkylene) nonionic surfac­tant having an average molecular weight of from 10,000 to 50,000, preferably from 15,000 to 30,000.
• the viscosity reducer is prepared by reacting a mixture of ethylene oxide and a higher epoxide having 3 to 4 carbon atoms such as propylene oxide or butylene oxide with a hydrophobic initiator preferably obtained by reacting an aliphatic diamine such as ethylene diamine with a higher epoxide having 3 to 4 carbon atoms such that the ratio of ethylene oxide to higher epoxide in the hydrophilic portion is from 10:1 to 1:1, preferably from 5:1 to 1:1.
• the heteric poly(oxyalkylene) nonionic surfactant is prepared by methods well known in the art. Essentially, the initiator is reacted with a mixture of ethylene oxide and a higher epoxide having 3 to 4 carbon atoms such as propylene oxide or butylene oxide at increased temperatures in the presence of an oxyalkylation catalyst.
• the amount of liquid viscosity reducer used is generally from 0.1 to 10.0 percent by weight, preferably from 0.3 to 3.0 percent by weight, based upon the total weight of the coal-aqueous mixture.
• Water is the other component of the coal-aqueous system and is used in amounts of from 60 to 10 percent by weight, preferably from 50 to 25 percent by weight, based upon the total weight of the coal-aqueous system.
• Additional components may be added to the coal-­aqueous mixture such as defoaming agents, thickeners, salts, bases, other flow modifying agents and combinations of these materials.
• the defoaming agents that can be used are conventional and include both silicon and non-silicon containing compositions.
• the thickeners that can be added to the mixture are also conventional. They are added to increase the non-­settling characteristics of the composition. Suitable thickeners include xanthan gum, guar gum, glue or combina­tions of these materials, in amounts ranging from about 0.01 to 3.0 percent by weight, based in the total weight of the mixture.
• the heteric poly(oxyalkylene) nonionic surfactant is preferably mixed with water at atmospheric or nearly atmospheric temperature and pressure to obtain a concentrated solution which is then mixed with pulverized coal and water to obtain a flowable liquid.
• a defoaming agent can be added to the water at this point to assist in processing.
• a thickener can be added to provide protection against settling.
• Other additives such as salts or bases can also be added to assist in dispersing.
• BCS TETRONIC® 1307 nonionic surfactant
• HCS heteric analogue
• Table I which follows, shows the dissolution time for various concentrations of BCS both molten and in water:
• Table I shows that flaked BCS at concentrations of 10 percent in water has the lowest dissolution time.
• Table II illustrates the dissolution time for various concentrations of HCS containing different percentages of propylene oxide in the heteric chain.
• the molecular weights of all the HCS products was approximately 15,000.
• Table II it can be seen that all of the HCS products performed better than the molten BCS products at comparative concentrations.
• the flaked BCS did perform better at 10 percent concentrations than all the HCS products except that containing 30 percent propylene oxide. All of the HCS products performed better at 20 percent concentrations.
• the best dissolution time for all of the surfactants tested was HCS/30 containing 30 percent propylene oxide.
• HCS/30 was compared to BCS with respect to its effectiveness in reducing the viscosity of various coal-water mixtures.
• the coal-water mixtures were prepared by dissolving 30 percent of the surfactant in water and by adding the resulting solution to a blend of water and various coals such that 90 percent of the particles have a diameter smaller than 160 ⁇ m and 100 percent is less than 250 ⁇ m.
• the coal-load in the mixture was determined by heating the mixture in a microwave oven repeatedly for 15 minutes or until no more weight loss was measured.
• the viscosities were measured by using a Haake Viscometer (Model XV100) and a MV2P spindle.
• the viscosity was measured by increasing the shear rate from 0 to 512 rpm over a four minute period. The Viscometer was maintained at that rate for one minute. The shear rate was reduced to 0 over a four minute period. The same cycle was repeated and the viscosity was measured at 100 sec. on the second descending curve. The results of the experiments are shown in Table III.
• HCS/30 is an effective viscosity reducer for all coals tested and is in some cases, (Datong coal and Polish coal) more effective than BCS, a well known viscosity reducer for coal-aqueous systems.
• HCS/30, as well as other types of HCS products, have the added advantage that they more readily dissolved in water and do not have to be molten or flaked. This saves time, money, and permits a more efficient operation.

Landscapes

• 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)
• Emulsifying, Dispersing, Foam-Producing Or Wetting Agents (AREA)
• Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
• Liquid Carbonaceous Fuels (AREA)

Applications Claiming Priority (2)

Publications (2)

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Cited By (2)

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• 1987
  • 1987-07-18 EP EP87110442A patent/EP0255006A3/de not_active Withdrawn
  • 1987-07-31 ZA ZA875666A patent/ZA875666B/xx unknown
  • 1987-07-31 JP JP62190562A patent/JPS6341593A/ja active Pending
  • 1987-07-31 AU AU76340/87A patent/AU7634087A/en not_active Abandoned

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