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EN
Analysis of granulation kinetics was carried out using a laboratory disc granulator with a diameter D of 0.5 m. A liquid binder was delivered to the tumbling bed at a constant flow rate with a nozzle generating droplets with a size of approx. 4-5 mm. Fine-grained chalk was used as a model of raw material and water or disaccharide solution with concentrations of 20 - 40% as a wetting liquid. Different times of droplet delivery ranging from 2 to 6 min were utilized. Granulometric composition of the bed for selected lengths of process, bed moisture and the moisture of individual size-fractions were assessed. Mass of granulated material, which was transferred from nuclei fraction to other size fractions was determined on the basis of mass balance analysis and the assessment of liquid migration between fractions. The influence of disaccharide concentration in wetting liquid on the aforementioned phenomena was also examined.
PL
Przedstawiono ocenę wpływu warunków nawilżania złoża w procesie granulacji talerzowej, na powstawanie i wzrost aglomeratów w okresie dostarczania cieczy wiążącej. Proces granulacji prowadzono w sposób okresowy w granulatorze talerzowym o średnicy D = 0,5 m i wysokości obrzeża H = 0,10 m, przy stałej prędkości obrotowej n = 0,167 s-1 i stałym kącie nachylenia osi talerza do poziomu α = 48°. Stosowano stałe objętościowe wypełnienie granulatora surowcem drobnoziarnistym ϕ = 0,05. Określano wpływ wilgotności złoża, intensywności nawilżania i położenia zraszacza na skład granulometryczny złoża otrzymanego bezpośrednio po zakończeniu dozowania cieczy wiążącej.
EN
Evaluation of the influence of bed wetting conditions during periodic disc granulation on the nucleation and growth of agglomerates is presented. The process of granulation was carried out in a disc granulator of diameter D = 0.5 m, rim height H= 0.1 m, at constant rotational speed n = 0.167 s-1 and slope angle between the disc and horizontal level α = 48°. A fixed volumetric disc filling with powder material equal to ϕ = 0.05 was used. The influence of bed moisture content, wetting intensity and location of sprinkler on particle size distribution of feed obtained after completing the wetting was determined.
3
Content available remote Granulacja popiołów lotnych uzyskanych ze spalania węgla brunatnego
PL
W pracy przedstawiono wyniki badań dotyczących granulacji popiołów lotnych. Granulację prowadzono w sposób okresowy w granulatorze talerzowym przy stałej prędkości obrotowej 30 obr/min. Materiał sypki nawilżano podczas ruchu przesypowego przy stałym natężeniu zraszania. Otrzymane wyniki pozwoliły określić parametry procesu oraz właściwości uzyskanego granulatu.
EN
Investigation results dealing with the granulation of fly ashes are presented in the paper. Granulation was conducted periodically in a disc granulator at constant rotational speed of 10 rpm. Loose material was wetted during tumbling at constant volumetric liquid flow rate. Results allowed one to describe process parameters and acquired granulate properties.
4
Content available remote Nucleation and granule formation during disc granulation process
EN
The study of nucleation and granule formation in a bed of fine-grained material during the phase of batch damping in the process of periodical disc granulation was conducted. The study was carried out on laboratory disc (diameter - 0.5 m), with the use of constant disc filling with powder material, constant slope angle 50 between the disk axis and level and constant rotational speed of device. Foundry bentonite was used as the examined material and distilled water as a binding liquid. The binding liquid was added in the form of droplets having constant size. The size of droplets was changed in the range 2.44.9 mm. The influence of number and size of binding liquid droplets delivered to bed, as well as of their delivery height on the size distribution of nuclei generated in the dumping phase was determined.
PL
W pracy przedstawiono wyniki badań wpływu wybranych parametrów procesowo-aparaturowych na właściwości produktu wytworzonego w procesie mokrej granulacji talerzowej w układzie ciągłym. Jako zmienne parametry stosowano prędkość obrotową talerza, kąt nachylenia jego osi oraz natężenie podawania surowca proszkowego. Jako modelowy materiał drobnoziarnisty stosowano bentonit odlewniczy, a jako ciecz wiążącą użyto wodę destylowaną. Stosowano stały stosunek natężenia podawania cieczy wiążącej do natężenia podawania surowca, równy 0,4 kg cieczy/kg proszku. Opracowano zależność wpływu badanych parametrów na wartość średniego rozmiaru granul w produkcie końcowym, otrzymanym po ustaleniu się warunków procesu ciągłego.
EN
The paper presents the results of the study of process-equipment parameters influence on the properties of product formed in the continuous, wet, drum granulation process. Plate rotational speed, the inclination angle of its axis and the intensity of powder material delivery were treated as variable parameters. Foundry bentonite powder was used as model of fine-grained material and distilled water as binding liquid. Constant ratio between the intensity of binding liquid delivery and the intensity of raw material delivery, equal to 0.4 kg of liquid/kg of powder, was applied. The influence of study parameters on the average size of granules in the final product obtained after the establishment of continuous process conditions was worked out in this study.
EN
This paper presents a method for quantitative assessment of the mechanisms of nucleation and granules growth by layering in the process of bed wetting during periodic disc granulation. This study included two initial, consecutive stages of a process with defined time courses. The first phase was a time period, in which only formation of new nuclei took place, while in the second stage simultaneous nucleation and growth of granules as a result of sticking raw material grains to preexisting nuclei occurred. Different kinds of binding liquid were used for bed wetting in each phase. In the first phase, an aqueous solution of dye was used, and pure distilled water in the second stage. The contribution of particular mechanisms to the formation of agglomerates at different time points within the second phase of the process was determined in this study. To do that the results of bed granulometric analysis, mass balance of size fractions and the analysis of contents of a marker (dye) delivered to the bed with the binding liquid during the first phase in agglomerates were used. To assess the concentration of the dye in different size fractions of the batch, spectrophotometric analysis was utilised. The study was performed using UV-VIS JASCO V-630 spectrophotometer equipped with an integrating sphere. The sieve analysis, spectrophotometric studies and mass balance were used to determine changes in the weight of the dye containing nuclei and of the nuclei containing no dye. The aforementioned analyses were also used to assess changes in the weight of formed granules and of raw material particles attached to nuclei during simultaneous nucleation and growth of granules.
PL
Doświadczalnie określono zmiany momentu obrotowego podczas procesu granulacji bentonitu odlewniczego w granulato-rach talerzowych. W czasie badań zmiennymi parametrami były: średnica bębna granulatora, kąt pochylenia talerza i stopień wypełnienia talerza materiałem ziarnistym. Podczas każdej próby mierzono chwilowe wartości momentu obrotowego na wale granulatora. Przeprowadzono ocenę wpływu średnicy aparatu, oraz wilgotności granulowanego złoża ziarnistego na zmianę momentu obrotowego.
EN
Changes of torque during fine material (foundry bentonite) granulation in disc granulators were investigated. A diameter and angle of inclination of the disc and its filling with, granular material were selected as varying parameters. During each test instantaneous values of torque acting on the granulator shaft were measured. The effect of disc diameter and moisture content of a granular material bed on torque in the whole granulation cycle was measured.
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