| dc.description.abstract | A transient conduction model was implemented in Python to assess the temperature development of NPK particles, produced at Herøya, Porsgrunn. Temperatures when hitting the tower bottom was calculated to be 102.8, 67.5 and 35.5 degC for the core, critical radius and surface respectively. The heat release from the prills was compared to an older model, and the updated model reduced the error from 10.98 to 1.30 %.
A sensitivity analysis was performed on the updated model, varying different parameters. Overall, the temperature was most influenced by the particle diameter, followed by the thermal conductivity. Air temperature influence increases while the radius increase, while the opposite is true for air pressure. Measurement data from the sensitivity analysis was used to produce two different methods for analyzing how the behavior of a process is expected to change, based on parameters; The EAD method, and the Trend-line method. Both showing good results within the reference framework.
The updated model was reconfigured to assess different products, produced at Herøya. Core temperatures were used as a predictor of crystallization degrees through a phase-diagram, which ranged from 93.4 % to 95.0 % for particle sizes of 2.85 mm. While the model shows basic forms of compatibility, further chemical and thermodynamical data is required to assess whether the model produces accurate results or not. | |
