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, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
  • C10L5/00—Solid fuels
  • C10L5/02—Solid fuels such as briquettes consisting mainly of carbonaceous materials of mineral or non-mineral origin
  • C10L5/06—Methods of shaping, e.g. pelletizing or briquetting
  • C10L5/10—Methods of shaping, e.g. pelletizing or briquetting with the aid of binders, e.g. pretreated binders
  • C10L5/14—Methods of shaping, e.g. pelletizing or briquetting with the aid of binders, e.g. pretreated binders with organic binders

Definitions

• the common binders for hard coal briquettes are pitch and bitumen. Because briquettes with these binders do not burn without smoke and soot and break down too quickly due to softening of the binder, so that unburned coal falls through the grate, there has been no lack of attempts to improve hard coal briquettes by choosing other binders.
• a new briquette that meets the requirements of the domestic fire market from a comfort fuel must have good loading, weather resistance and fire resistance, it should burn free of smoke and soot and the combustion gases must be free of pollutants.
• Loading strength means that the briquettes are so strong about 20 minutes after being pressed that they can withstand the mechanical stresses when loading them into wagons, buckets, trucks and the like. have grown without breaking.
• This strength in the cold state should increase with a greater time interval from the pressing, but in no case should it drop noticeably again, in order to ensure that briquettes are resistant to trade and consumers.
• the weather resistance indicates whether and to what extent the briquette strength can decrease due to the influence of air humidity and precipitation when stored outdoors. If it also increases again due to drying, for example due to solar radiation, it should not, however, fall below a point pressure resistance according to DIN 23081 of 50 kg.
• the stability of the briquettes in the fire is ultimately the goal of any briquetting. Since fine-grained material, such as washed anthracite fine coal, fine coke of any kind and similar fine-grained fuels, cannot be burned in domestic furnaces, they are made into pieces by pressing with a binder and are therefore usable like nut coal. It would make no sense for the briquettes to fall apart at the start of the combustion and to pass through the grate into the ash pan as unburned material.
• a new binder should be easy to work with and should not cause any nuisance to the workforce or the surroundings of the briquette factory. If a briquette factory with a conventional procedure already exists, the new binder should not require extensive renovation or even the new construction of the briquette factory for market and cost reasons.
• Molasses have also been proposed as an organic binder. But it turned out because of its water dissolving! and long solidification time for modern briquette processes as unusable and could not be introduced in the past due to the poor weather resistance. In order to improve the resistance to weathering, it is also known, the molasses sulfuric acid or substances which form in their Verset- i Zung sulfuric acid to mix, but what is ruled out today because of the increase in the sulfur dioxide content in the exhaust gas.
• the invention accordingly relates to coal or coke briquettes which contain 1 to 3, preferably 1.5 to 2.5% by weight of molasses and 0.3 to 2, preferably 0.5 to 1.5% by weight of a fully hydrolyzed polyvinyl alcohol with a Viscosity of 40 to 100, preferably 50 to 70 mPas, each based on the dry matter of coal or coke.
• Fully hydrolyzed polyvinyl alcohols are those with a degree of saponification or hydrolysis of the underlying solvolysed polyvinyl acetate of over 97 mole percent, in particular 98 to 100 mole percent.
• the fully saponified polyvinyl alcohols with high viscosities suitable for the purposes of the invention are commercially available, for example, as MOVIOL R types 56-98 and 66-100 (HOECHST).
• the invention further relates to a process for the production of coal or coke briquettes, in which the fine-grained fuel heated to a temperature of 100 + 20 ° C. is heated with an aqueous binder solution which is 70 to 100 ° C., in particular 80 to 95 ° C. Molasses and the polyvinyl alcohol sprayed, the mixture of fuel and binder solution, optionally with additional heat, homogenized and pressed with good dewatering to briquettes.
• briquettes made of anthracite coal with an aqueous binder solution which, however, contained only the specially selected fully saponified polyvinyl alcohol but did not contain molasses
• briquettes with a fairly good loading resistance and very good ones have already been produced Ultimate strength achieved.
• the stability in water was sufficient immediately after production, but improved noticeably after 24 hours.
• the heat resistance i.e. the stability of the briquettes in the fire, can still be used for domestic furnaces without too much unburned coal falling through the grate in the ash pan during combustion, but appears to be in need of improvement, especially for use in heating boilers, so that these smokeless briquettes also very low emission value can also be used there.
• Tubular or beet molasses are useful for the purposes of the invention.
• Beet molasses is obtained with a dry substance of 85 to 89%, with tubular molasses the water content is usually somewhat higher.
• Molasses has a high content of carbohydrates, especially sugar, as well as non-sugar substances, especially amino acids and nitrogen-free carboxylic acids, in the order of about 40%.
• the fully saponified polyvinyl alcohol of the required viscosity range is expediently first dissolved in hot water and then mixed with the generally undiluted molasses. This gives an aqueous solution with 15 to 30% dry matter, which is sprayed hot on the coal and then in a suitable mixing unit, e.g. a double mixing screw, well mixed with the coal.
• a suitable mixing unit e.g. a double mixing screw
• the heat resistance can be further improved by adding up to 2% by weight of powdered calcium carbonate, based on the dry matter of coal or coke. Part of the molasses can also be replaced by calcium carbonate. In order to be fully effective in the mixture, the calcium carbonate should be as fine as possible and should have a grain size of less than 100 ⁇ m.
• Calcium carbonate can be used in its finely powdered, pure natural or synthetic forms. Only for the purposes of the invention, cheaper products such as ground limestones, such as lime slate, marble, marl, chalk, stalactites or limestone tuff, are preferred for reasons of cost.
• the limestones can also contain a certain percentage of dolomite.
• Precipitated calcium carbonates are also usable for the purposes of the invention, which accumulate in chemical processes as a waste product and do not even dry need to be, because even with the incorporation of a slurry in the mixing units, sufficient homogenization can still be achieved with the fine-grained fuel and because the use of the aqueous binder solution according to the invention requires dewatering anyway.
• the weather resistance of the briquettes can be increased by spraying the freshly pressed briquettes with a high-percentage, in particular saturated sodium carbonate solution or briefly immersing them in them.
• Fine-grained fuels such as e.g. Anthracite coal, fine coke, flame coal, fat and lean coal, eating coal, lignite and charcoal are used.
• the stability of the briquettes in water is checked as a measure of the weather resistance. Immediately after pressing and then at certain intervals, 10 briquettes are placed in a water bath. After a dwell time of 15 minutes, they are removed and their strength is immediately tested using the cold strength method. The start of water bathing is the time of the water resistance.
• the heat resistance of the briquettes is examined to determine their stability in the fire. 5 briquettes are placed in a muffle furnace heated to 600 ° C and removed after certain time intervals. Then they are loaded on the test press immediately after the cold strength process until they break.
• combustion tests are carried out in the house furnace in accordance with the test regulations of DIN 18 890.
• the ash content is determined on the basis of the grate diarrhea.
• the soot-tar number is also identified as an indication of the emission.
• the pollutants in the exhaust gases are measured using the method described by Ahland / Merten in VDI report No. 358/1980.
• the aqueous binder solution is sprayed in a quantity of 10 1/100 kg coal at a temperature of 80 to 95 ° C onto washed anthracite coal, which in turn is heated to 100 ° C + 20 ° C.
• the briquettes are then processed into egg briquettes in conventional double-roll presses.
• the various strengths, emission values and the analysis of the exhaust gases were then carried out as described above.
• the final strength was excellent at 950 N.

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• Chemical & Material Sciences (AREA)
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• Environmental & Geological Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Geology (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Solid Fuels And Fuel-Associated Substances (AREA)

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Citations (6)

• 1983
  • 1983-09-29 DE DE19833335242 patent/DE3335242A1/de not_active Withdrawn
• 1984
  • 1984-08-17 EP EP84109822A patent/EP0135784A3/fr not_active Ceased

Patent Citations (6)

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