CS209517B2 - Coal briquettes with decreased emission of solid substances - Google Patents

Description

(54) Coal briquettes with reduced solids emissions

The invention relates to coal briquettes with reduced solids emissions.

For shaping coal dust into briquettes, a binder is required, which is suitable for its "normal pitch" for its excellent bonding properties. 'Normal pitch' is the remainder of coal tar distillation, a black, thermoplastic product with a Kramer-Sarnow softening point (hereinafter referred to as KS) of about 68 ° C (see Franck, Collin: Steinkohlenteer, Springer-Verlag 1968, p. 96). However, the disadvantage of such briquettes is that they smoke during combustion. There were therefore no attempts to replace coal pitch with other binders.

As bituminous pitch substitutes in the production of briquettes, petroleum bitumen binders are of practical importance (see Zakar, Toth: Brennstoff-Chemie 39, 1958, p. 373). Although briquettes made using bitumen as binders do not smoke as much, they have drawbacks from coal-bituminous briquettes from another point of view: base binders, petroleum resins have a higher sulfur content and therefore cause greater sulfur dioxide emissions compared to bituminous pitch. In view of the flatter viscosity curve of the resin as a function of temperature, a longer cooling time after the briquetting process is required to give the briquettes the necessary cold compressive strength. In addition, bitumen-bonded briquettes have less hot compressive strength than pitch-bonded briquettes. Therefore, during combustion, k. briquettes in the stove become more disintegrated, so that when the ash is shaken off, unburned briquettes also partially disintegrate and, while still burning or incandescent, they fall into the ashtray of the stove, which disrupts the uniform burnout.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide coal briquettes which combine the advantages of coal briquette briquettes with strength properties with the advantages of binder-briquettes with low solids emission.

The object of the present invention is to solve coal briquettes with reduced solids emissions, characterized in that they contain as binder hard coal pitch with a Kramer-Sarnow softening temperature of 120 to 200 degrees Celsius treated hydrocarbon fraction with a distillation range of 220 to 450 ° Obtained by pyrolysis of coal tar or petroleum fractions to a softening point of 50 to 100 ° C.

The briquette binder preferably contains anthracene oil to adjust the final softening point of the coal pitch. A pyrolysis oil fraction from the pyrolysis of petroleum hydrocarbons to ethylene can also be used for this purpose.

Hard pitch used as a starting material for the production of binder can be obtained from known hard pitch processes (see HJV Winkler, Der Steinkohlenteer. Und Seine Aufarbeitung, Verlag Gluckauf, Essen 1951, p. 204; Franek, Collin 1. cs 52). the resulting pitch distillate is again, but not completely, returned to pitch. Preferably, the hard pitch is obtained by purely distillation treatment of normal pitch, i.e. by distillation under vacuum at 50 to 50 psi, in particular 20 to 50 psi.

The briquettes produced by conventional pitch briquetting processes according to the invention have the advantage over briquettes made from normal pitches of lower solid emissions values that are comparable to those of briquettes made from petroleum resins. In contrast to the latter, however, the briquettes produced using pitch according to the invention have even greater cold and hot compressive strengths and produce less sulfur dioxide.

The following are the solid emission values measured by the cold sump method, the smoke is eliminated in the cold sump and CO 2, SO 2 and water are evaporated from the precipitate to determine the emission value of solids, briquettes produced using normal pitch, petroleum bitumen and pitch according to the invention .

Emission value (g / kp)

Type of binder

Binding ratio (%)

Normal pitch 7.0 40 to 45 Petroleum bitumen . 6.5 20 to 25 Example 1 6.5 23.6 Example 2 6.5 22.8

The boiling point data refers above and further, unless otherwise stated, to a pressure of 100 psig. Percentages are percentages by weight.

She said dl

Normal coal pitch with a softening point of 68 ° C is distilled up to a softening point of 154 ° G. 1750 g of coal anthracene oil (withdrawn in the distillation range 300 to 400 ° C) are added to 5350 g of the hard pitch thus obtained and mixed well. Homogeneous · The mixture has the following analytical data:

softening point (KS) 69 ° C toluene insoluble residue 41,6% quinoline insoluble residue 14,7%

Claims (3)

SUBJECT Coal having a reduced solids emission, characterized in that it is as follows: The binder contains a hard coal pitch having a Kramer-Sarnow softening temperature of 120 to 200 ° C treated with a hydrocarbon fraction with a distillation range of 220 to 450 ° C, obtained by pyrolysis of coal tar or petroleum fractions, for a hot softening of 50 to 100 ° C. The emission value of hard coal briquettes produced from this pitch (binder fraction 6.5 o / ₀ ) is 23.6 g / kp (cool sump method). Example 2 To 5390 g of hard pitch 154 [deg.] C obtained similarly to Example 1 was added 1610 g of pyrolysis oil fraction with a distillation range of 260 to 360 [deg.] C, from the pyrolysis of petroleum hydrocarbons to ethylene, and mixed well. The homogeneous mixture has the following analytical data: softening point (KS) 70 ° C toluene insoluble residue 43.7% quinoline insoluble residue 15.7% The emission value of hard coal briquettes produced from this pitch (binder content 6.5%) is 22.8 g / kp (using the cold sump method). YNÁLEZU Coal briquettes according to claim 1, characterized in that the binder contains anthracene oil to adjust the final softening point of the hard coal pitch. 3. Coal briquettes according to claim 1, characterized in that the binder comprises a pyrolysis oil fraction from the pyrolysis of petroleum hydrocarbons to ethylene to adjust the final softening point of the hard coal pitch.