Rheology of Coal

Rheological testing determines the flow characteristics of materials. Coking coals swell, soften and then re-solidify to form coke when heated in the absence of air. These rheological properties of coke in a furnace have a major impact on energy requirements and efficient process design in a coking operation. SGS uses the industry standard Gieseler Plastometer, Arnu Dilatometer and, in Russia, Sapozhnikov tests to accurately determine the rheological properties of your coke samples.

The data gained through rheological testing enables you to select coals that have the proper thermodynamic properties to make the high-quality coal that will improve the efficiency and the bottom line of your coking operation. 

SGS is a global leader in coal and coke laboratory analysis. Our experienced technicians and state-of-the-art testing laboratories provide quick turnaround of complete and independent rheological property test results from your coking coals. We ensure the quality and suitability of your coking coal samples for your operation. 

Gieseler Plastometer Test

SGS experts use the Gieseler Plastometer test to determine the plasticity range of coals, including the temperature at which initial softening, maximum fluidity, and resolidification occur. For this analysis, 5 grams of minus 40 mesh prepared coal is packed into a retort barrel along with a stirrer. A constant torque is applied to the stirrer and the coal is heated at 3°C/minute. As the coal softens, the stirrer begins to turn. The maximum fluidity value of your sample is expressed in dial divisions per minute (DDPM) of the stirrer rotation.

A plasticity range at OC and maximum fluidity in DDPM are key factors used to determine which blends of coals are optimal for coking.

Arnu Dilatometer Test

SGS technical experts use the Arnu Dilatometer test to determine the swelling properties of your coal sample when it is heated under standard conditions in a dilatometer. The sample is then placed in a furnace, and the apparatus is heated at 3°C/minute. We carefully monitor and record the movement of the piston as the coal cylinder shrinks and expands.

Characteristic Arnu Dilatometer curves are generated when the piston movements are plotted against the corresponding temperatures. The charts generated by our technical staff provide valuable information regarding the suitability of your samples for use as coking coals.

Sapozhnikov Test

This test is performed in accordance with GOST 1186. It is the main test used in Russia and Ukraine for determination of the coking properties of the coal. A sample is placed into the steel cylinder and pressed with the help of the piston and a prescribed weight. Heating is performed from the bottom (3°C/minute) and the temperature is measured on the bottom with a thermocouple. Between 350 - 650°C the lower and higher level of the plastic layer are detected with a needle and measured with a ruler. Y value (in mm) is determined as maximum thickness of the plastic layer.

Thickness of the coal briquette is measured during analyses. Correlation of the briquette thickness via temperature is plotted as a Plastometer curve.

Partner with SGS and leverage our technical capabilities to guarantee that your coal and coke analyses meet global standards for quality and excellence. Contact SGS to learn more about our rheological testing procedures and to provide you with accurate and timely coal analysis.

Gieseler PlastometerGieseler Plastometer and Arnu DilatometerEvaluating Rheological Properties of Metallurgical Coal ...

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  Gieseler Plastometer

  published 02/29/12

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