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

Definitions

• the present invention relates to a new type of liquid fuel, comprising a dispersion of solid particles in liquid phase, and to a method for manufacturing such a fuel.
• alternative energy sources which can be transformed into fuels replacing oil.
• fuels conceivable as alternative energy sources are the solid fuels, and not least fossil-type fuels such as shistous, peat, pitch coal and.mineral coal.
• carbonaceous, renewable energy sources from plants are considered such as wood, timer offall, algaes and seeweed, as well as cultivated biomass as straw, alder and sallow.
• the renewable energy sources are as a rule more rich in water and thus more difficult to disintegrate than the fossile ones.
• large power (thermal) plants have been developed, and combustion furnaces and gas purification plants have been adapted to this new fuel.
• Coal-oil mixtures are those which are most obvious, and the usefulness of such mixtures will be readily realised by those skilled in this particular art, in which the oil is extended by admixing finely divided wood, peat or coal therewith.
• One problem with such mixtures is that the solid material must be ground and substantially all water removed, and that the dry particles must then be wetted with oil and a homogenous dispersion of the coal in the oil produced.
• Methanol raises the price of the end product, since at least 30% by weight comprises methanol, and particularly because methanol is normally produced from coal or oil, with a thermal efficiency of about 50%.
• a particularly stable and easily combustible dispersion fuel can be produced by suspending aqueous finely-divided carbon-containing particles in a liquid of particular composition.
• This liquid may suitably be present in the state of a so-called micro-emulsion.
• the fuel comprises more than 50% by weight solid finely-ground carbon-containing particles, and the liquid phase of the suspension shall comprise more than 50% by weight water, 5-30% by weight of oil and up to 5% by weight emulsifier.
• These fuels can be prepared from a number of fossile and renewable energy sources by suitable development of the process, which will be more closely described in the following.
• An emulsion comprises two liquids which are only slightly soluble one within the other, in which one liquid is finely dispersed in the other.
• the finely dispersed liquid comprises extremely small droplets in the order of 3-100 nm in the other liquid
• the emulsion is normally referred to as a micro-emulsion.
• Micro-emulsions are stable at defined physical conditions and, if the liquids are transparent, are completely clear liquids. Normally micro-emulsions contain surfactants to enable sufficiently small, stable liquid particles to be formed.
• a micro-emulsion exists within certain temperature ranges and is sometimes dependent on the pH of the phases.
• the emulsion will be converted, via an intermediate stage in which the two phases comprise emulsified material and emulsifying agent, to a system in which the.previously finely-divided phase will be the phase in which the other phase is emulsified.
• a micro-emulsion may suitably be stabilized with fatty acid salts in combination with alcohols or amines.
• An optimal combination of surfactant as fatty acid salts and co-acting surfactant enables stable micro-emulsions having a high water content to be formed (Gillberg and Friberg ACS-Symposium and Evaporation-Combustion of Fuel droplets, San Francisco, August 1976).
• the alcohols may be monovalent or divalent and representative examples of such alcohols are pentanol, hexanol and heptanol, and also divalent alcohols such as hexandiol. Amines and aminor alcohols can also be used.
• Micro-emulsions are produced by, for example, dispersing oil spontaneously in water with the aid of mechanical forces and conventional surfactants. At given concentrations there are spontaneously formed clear transparent solutions with the addition of an alcohol or an amine having 5-7 carbon atoms, with emulsified droplets in the order of 8-80 nm. In technical processes no particular agitation is necessary to reach an emulsion. However, agitation to a certain extent may be necessary to bring large flows of different components together into intimate contact.
• dispersion fuels in micro-emulsion form, in which the oil phase comprises thick firing-oil.
• the amount of alcohol admixed is greater the higher the viscosity of the oil.
• thick firing-oil is meant thick, sluggish firing-oil with a viscosity from 5 cSt, preferably higher than about.10 cSt at 50°C and higher, such as firing-oil grade 3, 4, 5, and 6.
• An emulsifier is a compound of the group fatty acid soaps, carboxylic acids having 4-8 carbon atoms, carboxylic acid esters having 4-8 carbon atoms in the carboxylic acid part, alcohols having 4-8 carbon atoms, and carboxy amines having 4-8 carbon atoms.
• Nonionic emulsifiers can also be used, such as harmonic mixtures of hydrocarbons having a boiling point of 150-275°C.
• the new dispersion fuel constitutes a high-grade liquid fuel produced with a lower oil content and with a heavier firing oil than was previously possible.
• the novel fuel can be burned in small as well as large furnaces and plants and requires only the temperature to be maintained within the temperature range at which the micro-emulsion exists.
• By adding alcohol the lower temperature limit at which the micro-emulsion can no longer exist is decreased, which is an important advantage, and the risk of the.fuel freezing when being stored and transported reduced.
• a secondary effect is that the alcohol can be used as a fuel component.
• the presence of a lower alcohol means a drying of the solid fuel when preparing the same to.a dispersion.
• the novel dispersion fuel is suitably produced by integrating the manufacture of the fuel with the purifying processes normally required when mining and grinding the intended carbonaceous materials. Thereby the fuel can be prepared particularly economical and the raw material and other process resources be utilized optimally.
• Dispersion fuels on a micro-emulsion base provides for a completely new group of fuels to be prepared, which are all pumpable and mixable with oil, carbon-oil-suspensions, carbon-methanol-suspensions and carbon-water--suspensions.
• Dispersion fuels based on different carbon containing, combustible solid raw materials and their preparation will be more closely described in the following with reference to a number of Examples in order to clarify the general intentions set forth above and to further demonstrate the scope of the invention.
• the addition of replacing micro-emulsion was interrupted when the kerogene-micro-emulsion dispersion had obtained a composition comprising 60% by weight of solid kerogene in a liquid phase and 40% by weight of a micro-emulsion consisting of 55% by weight of water, 20% by weight of heavy mineral oil, 5% by weight of an emulsifier and 20% by weight of a lower alkanol,(methanol).
• the kerogene dispersion thus obtained was intended to be fed to a plant for pyrolyzis according to SE,A,7903283-5, from which plant shale oil and shale gas are produced.
• Lignite from Powder River Basin, Wyoming, USA having a moisture content of 30% by weight of water was subjected to a wet grinding in a rod mill and a ball mill in a liquid consisting of a micro-emulsion of water, heavy oil, a lower alkanol,(ethanol),and an emulsifier.
• the grinding was finished when a particle size less of 100 microns had been obtained.
• alkanol and emulsifier in adjustable proportions the final contents of the dispersion was adjusted to 65% by weight of lignite, 22% by weight of water, 5% by weight of heavy oil, 6% by weight of ethanol, and 2% by weight of an emulsifier. (All calculations made on the total weight of the dispersion).
• the dispersion had a viscosity of 470 cP.and was pumped to a power-heat plant where it replaced commonly used heavy oil No. 6.
• Petrocoke obtained at the final refinery of crude oil was subjected to wet grinding in a ball mill in a micro-emulsion consisting of 50% by weight of water, 12% by weight of so called slop oil, 26% by weight of a mixture of lower alkanols (C l - C4), and 4% by weight of an emulsifier until the particles of the petrocoke passed a mesh size of 90 microns.
• the dispersion obtained was used in a steamship engine.
• Crude peat was prepressed and dewatered using oil in accordance with SE,A,8101623-0.
• the peat-oil-mixture thus obtained was provided with a mixture of water, a lower alkanol, (methanol) and an emulsifier of supplementing composition to give a liquid phase in the form of micro-emulsion consisting of 51% by weight of water, 29% by weight of heavy oil, 16% by weight of methanol, and 4% by weight of an emulsifier.
• the micro-emulsion comprised 45% by weight of the dispersion fuel, which could be used for direct combustion in a heat plant for oil combustion or in a gasification reactor for oil.
• Crude peat was prepressed in an angle press to a moisture content of 70% by weight of water.
• the peat mass was then added to a filter press together with a micro-emulsion consisting of water, oil, alkanol, and emulsifier in which press the water content of the peat was separated off and replaced by the micro-emulsion.
• the filter cake thus obtained was provided with further micro-emulsion so as to obtain a composition in accordance with that of Example 4 above.
• the filtrate obtained was allowed to pass a bed of peat coke on which remaining organic compounds were absorbed, whereupon the peat coke after wet grinding to a small particle size was mixed with said dispersion fuel which had been adjusted to a power-heat-station originally constructed for oil.
• a mixture of wood of grown alder and grown sallow, as well as birch wood and pine forest waste was disintegrated and dried to a moisture content of 50% by weight of water.
• the wood mass was fed together with methanol-ethanol chilled to -90°C to a ball mill comprising ceramic balls.
• the mass as well as the liquid was fed to a second milling step.in which the grinding bodies consisted of coal pieces having a piece size of 20 to 70 mm.
• the total mass was ground to a particle size of below 0.5 mm.
• the filter mass was provided with a micro-emulsion consisting of water, heavy oil No. 3, lower alkanols, and an emulsifier to form a stable dispersion in a micro-emulsion.
• the ready-to-use fuel contained 55% by weight of solid substance, 27% by weight of water, 6% by weight of heavy oil No. 3, 9% by weight of alkanols, and 3% by weight of an emulsifier and was used to heat tap water in a separate apparatus in a district heating plant.
• Example 7 For the production of a dispersion fuel on basis of biomass according to Example 7 brown algae, straw were brought in, which components - were fed into the second grinding step of Example 7. The feeding of algae and straw comprised 25% by weight of the wooden mass.
• the addition of micro-emulsion was similar to the one of Example 7 but the proportions of the ingredients were varied with regard to the water contents of the algae and the straw respectively so that the composition of the liquid phase was the same as in Example 7 above.
• the final dispersion was used in a district heating plant for production of hot tap water.
• Coal from a pit was pulverized by wet grinding and the thus formed coal suspension was separated by density separation, suitably in washing cyclons in a lighter fraction, which after dewatering and optional further grinding is used for the preparation of a dispersion fuel, and a heavier fraction which is further ground and flotated.
• the coal may also be subjected to steam-splitting processes and leaching processes as a preparatory treatment prior to crushing the coal for further treatment.
• This method is described in SE,A, 7603646-6.
• the coal is treated with a liquid under pressure and having an elevated temperature, whereafter the pressure is rapidly equalized to atmospheric pressure, whereupon liquid which has penetrated the coal is rapidly vapourized and splits the particles at the grain boundaries.
• the liquid used may, for example, be water. If sulphur dioxide is available, this can be uset to advantage in liquid form or dissolved in water, and subsequent to being used may be re-condensed and optionally re-cycled.
• the material may be subjected to a leaching process such as to further loosen the grain boundaries and to facilitate further diminuation of the material, for example with a highly acid leaching liquid.
• a leaching process such as to further loosen the grain boundaries and to facilitate further diminuation of the material, for example with a highly acid leaching liquid.
• the finely-divided mineral coal which is free from sulphur, is passed to the dispersion-fuel manufacturing plant.
• a preceding, additonal purifying process may be carried out, by dividing the material into mutually different degrees of purity, by flotation or classification screening, where in the latter case coarse material is passed to a flotation plant prior to manufacturing the dispersion fuel.
• the material can be returned to a coal-agglomerating stage in which it is agglomerated with oil, whereafter the agglomerate is de-watered and passed to a mixer in which water, methanol and emulsifier are added and a micro-emulsion base is formed.
• This micro-emulsion base is mixed with the finely-divided coal phase in suitable proportions, i.e., so that the coal phase is more than 50% by weight of the dispersion fuel.
• coal phase has been described with reference to mineral coal, although it will be understood that other types of coal can be used, such as pitch coal, peat, asphalt and soot and coke products. Even biological products such as charcoal and biomass as well as shale material comprising kerogenes can be used as the solid fine--grain fuel.
• the impurity content of the solid fuel, in the form of inorganic salts and the like, will naturally be present in the ultimate dispersion fuel and, as will be understood, the presence of certain impurities must be taken into account when using the fuel.
• steam coal bituminous mineral coal
• One such steam coal has been obtained by treating so-called mining coal in a washing plant and is found available as bulk goods with a particle size beneath 40-50 mm.
• Manufacture of the fuel, described hereinafter, may either be effected in direct connection with the primary production of steam coal, or at some location in the transport chain up to the final consumer station.
• the coal required for the fuel mixture is supplied continuously to a wet-grinding plant, comprising a rod mill, in which the coal is ground down to a particle size of at most 3-5 mm.
• the particles in the pulverized coal smaller than about 100 urn are separated off and the pulverized coal is de-watered in a centrifuge and then subjected to a density-separation process in a cyclone having heavy medium, in a known manner. In this separation process, the coal is divided into a 3 light fraction having a separation limit of 1.3 g/cm .
• the light fraction having a high carbon content and lower ash content is treated by itself, while the heavier fraction, in excess of 1.3 g/cm 3 and having a low carbon content and a higher ash content, is also treated on its own, as hereinafter described.
• the light fraction is of such purity that subsequent to being filtered and further ground may be charged directly to the plant for the manufacture of dispersion fuel.
• the heavier fraction, having the higher ash content and lower carbon content, is subjected to a further grinding process, in which it is ground to a particle size smaller than 0.1 mm in a closed circuit which incorporates a cyclone.
• the circuit also incorporates a classifier, from which the coal-water suspension is passed to a flotation purifying stage, where ash and pyrite are separated from the suspension to obtain a purified coal, which is admixed with the finely-ground coal obtained from the lighter fraction.
• the coal-water suspension is passed to a thickener, where the major part of the water is removed from the suspension and returned to the process line.
• the thickened product is passed to a further de-watering stage on a filter which operates under pressure and which is heated in order to remove as much water as possible. Water remaining in the filter cake is then displaced therefrom with the selected micro-emulsion base in a further filtering or de-watering stage, wherein water present in the pores of the filter cake is replaced with micro-emulsion base.
• the solid substance content of the coal-liquid mixture and liquid contained therein are adapted by further adjustment to the composition of the mixture, with the aid of dry coal or more micro-emulsion base.
• the density separation process described in the introduction can be omitted in certain cases, the coal in its entirety being ground to a size smaller than 100 ) J m in a closed circuit which incorporates a classification apparatus.
• it may be particularly suitable to incorporate a sulphur-flotation stage in the grinding circuit, so that as much pyrite as possible is separated at the earliest possible point of time in the treatment process, as previously mentioned.
• the suspension of finely ground coal and water may be passed to a hydrocyclone and de-slurried.
• the coarser fraction i.e.
• the fraction containing particles preferably greater than 20 urn is subjected to coal flotation, thickening, filtering and displacement of the water phase with micro-emulsion, as described above, while the finer fraction, comprising particles smaller than 20 ⁇ m, is agglomerated with micro-emulsion in an excess quantity, from displacement of the liquid phase of the coarser fraction, and micro--emulsion comprising lighter oil components.
• the resultant fuels are particularly suited for diesel engines and more advanced combustion purposes.
• the surfactants can be selected so as to reduce the viscosity of the mixture, by selective adsorption on the mineral surfaces of further ionic substances, e.g., soap and fatty acids.
• a coal residue comprising 47% by weight of combustible material and 53% by weight of mineral was obtained. This residue was thickened and dewatered on a filter to a moisture content of 34% by weight based on the total. In a further filtration step the water was removed using a micro-emulsion consisting of water, heavy oil No. 5 also containing residues of organic solvents, and a mixture of lower alkanols, and an emulsifier. The coal residue thus treated thereby obtained a final moisture content of 32% by weight.
• the liquid consisted of a micro-emulsion of 51% by weight of water, 16% by weight of heavy oil, 21.9% by weight of alkanols, and 4.1% by weight of an emulsifier.
• the filtrate was recirculated and was used for flotation purposes in the preparation of the coal mentioned in Example 9 above.
• the dispersion of the coal residue was pumped to a gasification reactor for the preparation of a medium calorific,(about 300 B.T.U./c.ft.),synthetized gas whereby its energy content was well utilized.
• Example 10 In the treatment of a coal residue as described in Example 10 above an equal amount of peat transferred into a dispersion fuel in accordance with Example 5 above was added to the coal residue after thickening thereof.
• the fuel was fed by pumping to a gasification reactor for the preparation of medium synthetized gas.
• Bituminous mineral coal having a high gas content was flotated free from mineral ingredients and pyrite in accordance with Example 9..
• the purified coal was dewatered on a filter and a subsequent removal of water with a micro-emulsion. Between the steps of thickening and filtration 5 kg of magnesium powder to which 2.5 kg of aluminium powder had been added, and which had been finely ground in a mixture of methanol and heavy oil No. 3, were added.
• the thus prepared dispersion fuel consisting of 67% by weight of coal including metal powder, 3% by weight of heavy oil No.
• the described fuel mixture and its method of manufacture provide a pumpable, highly pure oil-like replacement fuel for oil, said fuel mixture having properties which lie close to those of oil.
• the fuel mixture provides a fuel which has substantially all the good properties of a coal-water mixture and which can be produced with a relatively limited amount of relatively low-grade oil and preferably from the alcohols methanol or ethanol, which in turn can be produced relatively simply.
• the risk of the fuel freezing which is a serious risk in other water-based systems, is substantially reduced.
• there is produced a fuel whose manufacture is only dependent on oil to a very slight degree.
• the combustibility of the fuel is greater than that of other water-based coal fuels.
• the flammability of the fuel can be further increased by adding aluminium or magnesium powder.

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• Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Dispersion Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Liquid Carbonaceous Fuels (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)
• Colloid Chemistry (AREA)

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• 1980
  • 1980-10-17 SE SE8007305A patent/SE443797B/sv not_active IP Right Cessation
• 1981
  • 1981-10-05 CA CA000387246A patent/CA1185792A/en not_active Expired
  • 1981-10-06 ZA ZA816900A patent/ZA816900B/xx unknown
  • 1981-10-13 JP JP56503269A patent/JPS57501632A/ja active Pending
  • 1981-10-13 EP EP81850186A patent/EP0051053A1/en not_active Withdrawn
  • 1981-10-13 WO PCT/SE1981/000298 patent/WO1982001376A1/en not_active Ceased
• 1982
  • 1982-06-02 DK DK247882A patent/DK247882A/da not_active Application Discontinuation
  • 1982-06-16 NO NO821998A patent/NO821998L/no unknown

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