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A method for drying hard coals using an impinging stream dryer has been proposed in the article. A series of screening tests were conducted, seeking optimum process parameters of an innovative coal impinging stream dryer using flue gas as the drying medium. The article addresses measurement results obtained for the flue gas and feedstock flow rate, feedstock sort, and initial moisture content on the specific energy consumption, volumetric water evaporation rate, and moisture reduction. The maximum volumetric water evaporation rate was found to be around 230 kgwater/m3·h and the maximum volumetric heat transfer coefficient came to ca. 2.5 kW/m3·°C. In terms of specific energy consumption, the lowest specific energy consumption was found to be around 1.79 kWh/kgwater. It was established that the relation between specific energy consumption and a product of the flue gas flow rate and the initial water (in the feedstock) flow rate is a power function. The best performance of the impinging stream dryer was achieved for high-moisture coal and high flue gas flow rates. The impinging stream dryer proved to be suitable for surface moisture removal from particulate materials that contain very high moisture. The initial tests conducted at the pilot plant successfully demonstrated reliable operation and promising results. [ABSTRACT FROM AUTHOR]

The densities of unloaded and partially carbonated piperazine (PZ) and 2-amino-2-methyl-1-propanol (AMP) aqueous solutions and their blends were measured at temperatures of 293.15 to 333.15 K. The results of these measurements were used to calculate excess molar volumes assuming that the volume of carbon dioxide dissolved in the solutions was zero. The excess molar volumes were correlated as a function of the CO2mole fraction using the Redlich–Kister equation. The results of the actual density are discussed in comparison with the case if no volume expansion occurs during the loading of the solutions. The no-volume-expansion model can be used to give an initial estimate of the density, while the Redlich–Kister equation is suitable for a precise density estimation. It must be noted that the no-volume-expansion model does not require any parameters except the density of the unloaded solution, unlike the Redlich–Kister equation, whose coefficients are regressed from experimental data. [ABSTRACT FROM AUTHOR]