Correction to: Dominant physical mechanisms governing the forced-convective cooling process of white mushrooms (Agaricus bisporus).

[This corrects the article DOI: 10.1007/s13197-020-04402-9.].

Investigation of nitrogen loss during laboratory scale fixed-bed drying of digestate.

In addition to the drying kinetics of digestate, a comprehensive knowledge is necessary on nitrogen loss and ammonia emissions in order to appropriately develop and design a dryer. Otherwise, these phenomena would result in environmental concerns and reduce the nutrient value of digestate. Expectedly, drying parameters considerably affect drying time. In this study, drying experiments were conducted at a laboratory scale fixed-bed dryer. The drying experiments were performed on dewatered digestate that mainly consisted of grass and maize silage (initial moisture content 76.4% w.b., 0.026 kg N kg-1 DM). The drying air temperatures were adjusted to 60, 70 and 80 °C, the airflow rate varied between 150 and 250 m3 h-1, respectively. As the results have shown, the total nitrogen was reduced by 29 to 42% during drying. Almost all ammonium nitrogen was lost (92%). No relationship between nitrogen loss and drying air temperature or airflow rate could be proved. These results will be used as a basis for further investigation of continuous digestate drying at a semi-technical scale.

Dominant physical mechanisms governing the forced-convective cooling process of white mushrooms (Agaricus bisporus).

Nowadays, numerical modelling has been extensively converted to a powerful instrument in most agricultural engineering applications. In this study, a mathematical model was developed to simulate the forced-air cooling process of mushroom. The simulation was performed in CFD code Fluent 19.2 and the conservative mass, momentum and energy equations were solved within the package. The accuracy of the model was then quantitatively validated against experimental data and very good agreement was achieved ( R o o t - M e a n - S q u a r e E r r o r RMSE ≃ 3.8 % ). It was confirmed that in addition to convective mode, water evaporation makes a major contribution in mushroom cooling. According to the results, the developed model was able to predict the velocity and temperature profiles with a reasonable accuracy. It also has a potential to be used in design and optimization of such processes.