CS276877B6 - The method of briquetting brown coal - Google Patents

Abstract

During the briquetting of brown coal or its mixture with other carbonaceous components, preferably heated above the soaking temperature of the binder, 2 to 26% by mass is added as a binder. distillation residue - tar from vacuum distillation of low-sulfur and/or medium-sulfur oil, or tar, with a dipping temperature of 30 to 90°c and a mass ratio of H/C of 0.09 to 0.13, in which 1 to 30% by mass of flammable homopolymer and/or copolymer of polyolefin is dissolved and/or melted and said mixture is briquetted by known methods.

Description

1 CS 276877 B6

BACKGROUND OF THE INVENTION The present invention relates to a method for briquetting brown coal even with higher ash content, optionally together with non-melting organic macromolecular substances, using a binder to improve the flammability and lowering of the briquetted brown coal.

Sub-bituminous types of coal, lignite, or peat can be briquetted on a large scale. Thus, briquetting of brown-haired binder was made in Germany and Australia. The brown-coal bearing plants have been in operation for many years in these cities. However, to make good lignite briquettes, more rules are needed. Sufficient moisture content (12 to 15% by weight of water) must be ensured by drying and sufficient pressure to deform and bond the particles to a compact unit. Such a required pressure is 100 to 200 MPa. In doing so, the brewing requirements require that the ash content of such coal be 15% by weight.

Bituminous coal, but also higher carbon angles and anthracite are not binder-treated briquettes. For these reasons, inorganic binders such as sodium silicate, sulfite liquor, limestone, cement or magnesium oxychloride are used for briquetting. Starches or comminuted cereals, corn flour and the like are used from organic binders. Further, briquetting uses pitch pitch or bitumen. The disadvantage of inorganic binders is the increase in ash content in briquettes.

The production process using coal tar pitch is such that coal up to 2 wt. the water is fed to the mixer and mixed with the ground pitch of about 10 mm. The coal mixture is then fed to a disintegrator where it is comminuted, further into a heater and briquetting device. Here it is heated by steam and molded at a pressure of 15 N.m '2. Such briquettes can be bonded by carbonization at 850 to 900 ° C. The possibility of bonding bituminous coal ground to 1.5 mm with a moisture content of up to 3% by weight. After sieving (to remove fine particles), the coals are fed to a fluidized bed reactor where, at 410 [deg.] C., tar is burnt to form a briquette suitable for household use (W. Franci, MC Peters: Fuels and Fuel Technology, Second Edition, pp. 131-136).

The mechanical strength of the brownish briquettes can be increased 6 to 10 times when the coal is ground in water at boiling at 100 ° C, mechanically drained to a water content of 45%, ground to 0 to 4 mm, dried to 8 to 15% the moisture and briquette content is at a temperature of 70 to 80 ° C at a pressure of 140 MPa for 10 seconds (Institute of Chemical Technology Prague, Fuel Technology 1985, p. 103). A binder of fuels and ores powders based on syrups (85 parts by weight), water (100 parts by weight), polyvinyl alcohol (2.5 parts by weight) and sodium alkyl arylsulfate (1 part) has also been described. 7 wt.% Of 100 wt. parts of the binder and molding was carried out by molding (Nipon Braun K. K., Nissei Co. Ltd., U.S. Patent 61,271,022).

Fuel briquettes can also be prepared by mixing 1 part CS 276877 B6 coal tar and 2 parts wood waste (Japanese patent 62 115 084). Coke with sufficient strength was prepared by mixing brown coal dust with a grain size of up to 1 mm with a moisture content of up to 11.5% by weight. mixing more than 7.8% of the sulphite liquor with a solids content of 42.3% by weight. The pressing is carried out at a temperature of 70 ° C and a pressure of 140 MPa (Naundorf W., Freiberg, Forschung A 1987, A 733, 4 to 93). Fuel briquettes can also be made by mixing 1: 1 to 6 wt. of wood dust and carbonaceous material by granulating the mixture (preferably containing 3 to 25% water) at a temperature of 120 to 320 ° C and a pressure of 150 to 650 MPa. By way of example, a mixture of one part wood dust with a moisture content of 13.1 wt. and 2 parts of coal dust with a water content of 12.3%. This is granulated at 200 ° C and 386 MPa. While brown coal can be briquetted without binder, coal requires binder for briquetting. To this end, tar pitch, petroleum bitumen, sulfite leachate, glue, synthetic binder, e.g., polyvinyl acetate, polyvinyl alcohol, calcium oxide, and inorganic bonding agents are used (Erdól Kohle, Erdgas Petrochem. 1987, 40 (12) 521). Furthermore, it is known (J. Formánek: Coal 1956, pp. 24-28) that the coarse valuable coal be dried to the water max content before briquetting. 30% or remove the ash so that the residue is max. 20% ash, which is technically and especially energy-intensive.

Other Procedures / A. Kotina: Engineering 4, 282 (1954) / brown coal dust is briquetted, black coal dust, peat, sawdust, etc., at high pressure and pre-drying below 10% humidity. Otherwise, pile up in an interesting way. Patent No. 221,937 appears to be obtaining high-alkalinity briquettes for an unsuitable H / C ratio.

Even though it has been published many times that brown coal is all-pelleted, respectively. briquetting without binders in briquette tests, the so-called brown energy coal with a higher content of about 45% by weight, it has been found that briquetting of such coal with a pressure of 200 MPa is not possible. Accordingly, it was necessary to concentrate by washing. Washing managed to reduce the ash content to 21%. The treated coal, after pressing at 200 MPa (high pressure rotary presses), could already be briquetted. However, the briquettes are very susceptible to destruction in any manipulation, resp. o-wetting. For these reasons, a suitable binder was available which was technically and raw material available and which would meet the quality requirements for briquettes. These must be stable enough to be handled and raised to prevent them from falling apart when wetted with water. After testing a wide range of organic materials, a suitable binder has been found that meets the requirements and increases the heat of combustion of coal briquettes.

Thus, according to the invention, the method of briquetting a brown coal with a higher ash content above 15% by weight. at normal or elevated pressure at 250 to 500 K, with the co-operation of a flammable organic binder, by bringing the ground brown coal or ground brown coal together with other carbonaceous solids with a hydrogen content of 3 to 15% by weight. and carbon 3 CS 276877 B6 20 to 60 wt. 2 to 26 wt. distillation residue of gudrone from vacuum distillation of low sulfur and / or heavy crude oil or a mixture of the distillation residue of crude oil - gudrone's by the tar distillation residue, with a soaking temperature of 30 to 90 ° C and a hydrogen / carbon weight ratio of 0.09 to 0.13 in which 1 to 30% by weight is dissolved and / or melted. a polyolefin combustible homopolymer and / or copolymer, wherein the mixture is briquetted. The advantage of this process is the fact that the distillation residues - gudrons from low sulfur and / or medium-sized oil, or asphalts are widely available products with low volatility and their higher content of hydrogen and carbon promote the combustion of the resulting briquettes by overheating them in their entire volume. with an ash content of up to 45 wt. in charcoal. For these reasons, it is not necessary to reduce the ash content of the low-caloric brown coal below 15% by weight, resulting in reduced processing costs. In addition to this, the asphalts have a high flash point above 200-300 ° C, so that processing safety is guaranteed. As a result of the higher H / C weight ratio in the binder, low alkalinity is also advantageous. In addition, it makes it technically possible to assess otherwise difficult-to-use wastes, whether based on non-molten natural macromolecular materials, on the other hand, on flammable plates, mainly on the basis of homopolymers and copolymers of olefins, acofoles, spent bags, overspray, plastic cuttings, waste atactic polypropylene and polyolefinic raw materials. Last but not least, the advantage is the low content of sulfur compounds in the smoke from the combustion of such briquettes.

Prior to granulation, coal must be pulverized to a particle size of less than 3 mm, preferably below 1 mm, to ensure uniform mixing with the binder - asphalt. In order to guarantee homogenization with the binder, it is advisable to heat the coal above the bending temperature of the asphalt used before briquetting. After homogenization, the mixture can be briquetted. While briquetting can be done cold in presses, it is more preferable to operate above the asphalt wetting temperature in a continuous plant. In the case where the temperature of the asphalt dipping is, for example, 38 ° C to 44 ° C, the amount of gudrone dispensed with coal can be used in a range of 8 to 12% by weight, as the higher asphalt content results in deformation of the briquettes of the press. (briquettes flow). In such a case, it is necessary either to reduce the gudrone content of the mixture, which in turn is reflected in a reduction in the calorific value of the briquettes, or to cool them by forced cooling or cooling. gudrons or asphalts with a higher dipping temperature.

Especially suitable here can be utilized, to evaluate just waste, evaluated polyolefins, non-standard granules of low-density, medium-density and high-density polyestylene, polystyrene, atactic polypropylene, copolymers of olefins and polyolefin-based secondary raw materials. Such include scrap shavings, overspray, worn-out packaging, non-standard polypropylene fibers, and the like, for fiber purposes.

In this way, further carbon dioxide of the solid and non-fusible component with a hydrogen content of 3 to 15% by weight and carbon of 20 to 60% by weight can also be technically used. These are mainly non-fusible physically> disintegrated organic macromolecular substances, especially natural-molecular materials such as wood flour and sawdust, hemicellulose low-use fibers practically absent from the production of cellulose, the so-called zero fibers, crumbled paper, ground crusts of machines, crushed corn cobs and shelves , ground straw, plevya pod.

When using asphalts, respectively. distillation residues - gudrons from vacuum distillation can be used: grilled quality of these, and still untreated, formed after distillation of the volatile fractions, or after their subsequent processing by blow molding, so-called fumed asphalts, where the temperature of the spraying, respectively, is adjusted by air oxidation. asphalts as well. However, from the economic point of view, the treatment of primary asphalt - gudrons is not necessary and the obtained briquettes meet the required requirements as well as common asphalts, respectively. distillation residues of vacuum distillation of low- or medium-density, respectively. mixtures of tar distillation residues. An important criterion of the binder of the present invention is the weight ratio of hydrogen to carbon. The higher it is, the flammability improves and the alkalinity decreases. Said H / C weight ratio is increased by additives such as non-fusible macromolecular materials as well as technically difficult to evaluate polyolefins. In addition to increasing the "hydrogen index", the additives also increase the viscosity of the binder at elevated temperature, increase the strength of the briquettes, their hydrophobicity, and improve the shelf life of the briquettes. Further details of the method and the more advantageous advantages are apparent from the examples. Example 1 (Comparative)

Brown coal with an ash content of 47.15 wt. was pre-dried to a content of 10 to 16 wt. in an electrically heated oven with forced air at 102 to 105 ° C. Then the grains were ground below 2 mm and below 1 mm. Compression was done in hydraulic press at coal temperatures of 20 to 80 ° C and pressure of 100 and 200 MPa. The size of the laboratory briquettes was 70 + 35 mm, the average weight was 50 g. In the worst case, the ash content was reduced to about 21% by weight and the enriched coal was again treated as described above.

The mechanical properties of coal (Table 1) were as follows: 5 CS 276877 B6

Table 1

Mechanical properties of laboratory briquettes. Type Water content /% / Pressing temperature / ° C / Pressing pressure 100 MPa, Tensile strength / MPa / 200 MPPressure pressure / MPa / Suction water /% wt / No 10.5 20 4.6 8.2 Decay during washed 13.2 20 5.6 9.2 1 minute grain size 15.5 20 6.2 9.8 below 10.1 80 - what [· "1 mm 12.6 80 6.2 9/1 14, 6 80 6,8 9,2 washed 10,2 20 briquettes briquette coal 12,9 20 disintegrates at below 15,0 20 when extruded 1 mm from mold disintegrates 10,1 80 12,6 80 14, 6 80

Similar results were recorded with a grain size of up to 2 mm. Example 2

Four coal brown coal sites, Baňa Handlová power plant, No-váka mine, Cígel mine, and Dolina Velký Křtíš mine were tested in a dust-proof manner.

The force analysis of coal dust on sieves below 1.2 mm /% wt / wt is shown in Table 2.

Table 2 Proportion of grains Mine Baňa Han- Baňa Baňa Dolina above mm Cígel dlová Nováky I. seam II. slo 1,2 · 1,95 13,3 17,7 30,5 13,2 1,0 0,5 7,1 3,7 9,5 7,5 0,5 13,6 31,0 25,3 26,7 27,5 0,31 29,4 15,0 35,6 14,5 28,8 0,25 14,2 5,0 2,5 6,3 8,6 Overflow 40,4 28,6 9 , 6 13.2 15.4 CS 276877 B6

The first tests were done on Coal Novak.

Tested additions:

5, 10 and 15 wt. urea-formaldehyde polycondensate (MF-glue) to 200 g coal after homogenization for 10 minutes by stirring at 25 ° C were pressed on a hydraulic laboratory press. After 80 hours of standing, the briquette was soaked in water in a Petri dish: - with 5% MF polycondensate without hardener - after 24 hours the coal was decomposed - with 10% MF polycondensate soaked in water - weak force in the fingers disintegrated - with 15% MF the polycondensate swelled - did not disintegrate - the same was repeated after application of the ammonium chloride hardener to. MF glue, application 5 and 10% MF glue - the briquette swelled with water, after drying the briquette it induced - application of 5% w / w. calcium oxide - in contact with water the briquette has been spilled - sulphite leaches application 5 to 10% by weight. for coal - when water is touched, the briquette is scattered - alcoholic fraction C5 to Cg of alcohol additions of 5 and 10% - pristake with water, briquettes are spilled - lubricating oil - addition of 5% by weight. - after soaking in water, bri-ketka has been spilled - addition of 5, 10 and 15% by weight. distillation residue of gudrone from vacuum distillation of mid-crude oil, with a soak temperature of 38-44 ° C; ash content 0.5 wt%; flash point above 220 ° C, density at 20 ° C, - 1.0 g.cm "3; carbon content 86.3 wt%; a hydrogen content of 8.8% by weight; of nitrogen by 1.0 wt. and sulfur3.5 wt. Mass ratio H / C (hydrogen index) = 0.102. Bri-kets were solid, shiny on the surface. After soaking in the water, they puffed up and did not fall apart.

After three days in briquettes containing 5% gudron (asphalt), the water-soaked portion was slightly swollen. With a content of 10 and 15 wt. asphalt coal briquettes remained intact. With the asphalt, all coal samples were tested, depending on the grain size and the asphalt content of the water, briquettes with asphalt content up to 7%. At 10 wt. addition, briquettes were stable even after 10 cycles of wetting (24 hrs water), and drying (24 hr air).

Additions of 15, 20 and 30% of asphalts were tested on coal mine Cigel. Meanwhile, with 15 and 20 wt. asphalt for coal dust could be pressed with 30% of asphalt, the mold was poured during the pressing, it was not possible to extrude the briquette.

The Baňa Dolina I. seam tablets were stable with only 15% asphalt, while II. the seam required 20% of the asphalt to prepare the upturned tablets. Example 3

The dust coal of Example 2 was analyzed for water content (W 1), ash content in dry matter (Ad). /% wt / wt; the heat of combustion (Qd® g), the calorific value (Qr ^) in MJ kg “1 and the sulfur content (Sa)% by weight, binder-free briquetting and binder-asphalt specified in Example 2.

Analysis of briquettes: SUB Baňa Dolina wrt Ad ndat QS Qri Sd I. seam without binding I. seam + 10% 12,1 31,0 26,6 15,1 2,8 asphalt 10,4 27,3 29,9 18, 4 3.0 seam + 15% asphalt 9.8 27.0 29.3 18.3 2.6 II. binder bed without II. seam + 10% 13,6 53,7 27,0 10,0 2,5 asphalt 11,9 46,6 30,0 13,3 2,7 SUB Mine Nováky without binder 9,2 47,7 24,5 10 , 9 2.7 + 10% asphalt 9.6 42.1 28.2 13.9 3.1 SUB Mine Handlová without binder 10.4 47.3 12.8 12.0 1.8 + 10% asphalt 7 9 41.1 16.3 15.1 1.9 SUB Mine Cíge • without binder 10.7 62.5 8.1 7.5 1.2 + 10% asphalt 9.6 53.5 12.6 11.8 1.6 Subsequently, asphalts were tested with a soaking temperature of 53, to 93 ° C, the type of semi-blown, honest petroleum, oxidized and cauliflowers. When working at a sample homogenization temperature of 20 to 30 ° C above the soaking temperature (coal and asphalt heated to 80 to 120 ° C) with the addition of 10 wt. asphalts, all briquettes were waterproof, solid and shiny. Example 4

The procedure is similar to that described in Example 3, only to the applied distillation residue of gudron containing 86.5% by weight. carbon, 9.2% w / w (hydrogen index = 0.106); 0.9 wt. 10% by weight of nitrogen and 3.4% by weight after heating to 230 ° C. of polypropylene fibers (spun colored so that the hydrogen index rises to 0.112. Water content in briquettes from SUBBana Cíge coal drops to 9.2% by weight, ash in dry matter to 53.3% by weight, sulfur to 1 , 25% by weight and the calorific value increased to 12.0 IU / kg Example 1

The procedure is similar to that of Example 4, except that 12% by weight is added to the powdered brown coal. beech sawdust with a carbon content of 41.1% by weight. and 5.2% by weight of hydrogen. This reduces the ash content in the dry to 45.5% by weight. and sulfur to 1.08 wt. The hydrogen index rises to 12.2 MJ.kg-1.

Claims (2)

EN 276877 B6 8 PATENT CLAIMS 1. A method for briquetting brown coal with a higher ash content above 15% by weight. at normal or elevated pressure at a temperature of 250 to 500 K, in association with a combustible organic binder, characterized in that the ground brown coal or ground brown coal together with other carbonaceous solid components with a hydrogen content of 3 to 15% wt. and carbon 20 to 60 wt. 2 to 26 wt. distillation residue of gudrone from vacuum distillation of low-sulfur and / or medium-sulfur oil, or a mixture of distillation residue of crude oil - gudron with tar distillation, with a soaking temperature of 30 to 90 ° C and a hydrogen / carbon weight ratio of 0.09 to 0.13 in which and / or melts 1 to 30 wt. of a polyolefin combustible homopolymer and / or copolymer, wherein the mixture is purified. 2. Process according to claim 1, characterized in that the carbonaceous solid components are non-fusible physically disintegrated organic acromolecular substances, preferably natural macromolecular substances. End of document