Exergetic, Energetic, and Quality Performance Evaluation of Paddy Drying in a Novel Industrial Multi-Field Synergistic Dryer

Abstract

The present work proposes a novel industrial multi-field synergistic dryer with a drying capacity of 3.45 t/h. The energy, exergy, and quality aspects of the drying process were studied. An energy–exergy methodology was employed to estimate the energetic and exergetic performance, heat loss characteristics and heat recovery behavior of the dryer. Additionally, the quality of the dried paddy seeds was evaluated by its crackle ratio, generation potential, and generation rate. The results showed that the overall energy and exergy efficiency ranged from 13.26% to 56.63% and 39.03% to 60.23%, respectively. The improvement potential rates of the whole system varied from the lowest 8.49 kW to the highest 15.83 kW and respectively accounted for 15.81%–29.48% of the total exergy input, indicating that the performance of the dryer is acceptable. The total recovered radiant energy and radiant exergy recover rate were respectively ascertained to be 237.64 MJ and 0.26 kW. As for the quality aspect, the generation potential and generation rate of the dried paddy seeds respectively ranged from 75% to 90% and 69% to 88% while the crackle ratio of the paddy seeds was 1%, which indicated that the quality performance of the dried seed is of economic viability.

Study on the Variable-Temperature Drying Process of Corn Drying in an Industrial Corn-Drying System Equipped with a Self-Adaptive Control Heat Exchanger

“…The generally used heat and mass conservation equations were adopted to analyze the thermal performance of the components and the whole drying system. The heat and mass conservation equations in rate form were expressed as Equations 1and 2, respectively [9,19,20]:…”

“…The heat loss of the system (Q loss,wholesystem ) mainly consisted of four parts which were heat loss in outlet hot air (Q air,out ), heat loss in outlet corn (Q c,out ), heat loss in outlet flue gas (Q fg,0 ) and the total heat loss in components (∑Q loss ). Based on the analysis above in Section 2.5.1, the Q loss,wholesystem in rate form can be calculated by the following Equations (32)-(35) [20]:…”

“…During the drying process, the thermal energy in the flue gas after HE was transferred to radiant energy, which can enhance the drying even better than thermal energy [38]. Moreover, a proper far infrared wavelength can cause the resonance of moisture molecules in the corn kernel and increase the internal energy of the corn kernel, thereby strengthening the drying performance [20]. The variations in recycled radiant energy rate ( • Q FIR ) and the far infrared wavelength (λ) with drying time for different drying processes are depicted in Figure 5.…”

“…The reduction of heat loss was another effective method to improve the energy utilization level of the drying system. In order to further validate the feasibility of the optimized drying process, the variations in heat-loss rates in outlet air ( [20]. On the other hand, the • Q f g,0 varied in a relatively small range for the processes of α = 75 • and α = 90 • , while for the optimized drying process, the • Q f g,0 in the first cycle (0-90min) was obviously lower than that in the other four drying cycles, which might be due to the fact that the T fg,0 and v fg in the first cycle (α = 45 • ) were lower than those in the second, third, fourth and fifth drying cycles.…”

Developing an Online Measurement Device Based on Resistance Sensor for Measurement of Single Grain Moisture Content in Drying Process

“…The grains were then removed from the refrigerator and dried to achieve the target moisture content necessary for the experiment. The moisture content of the samples was determined by air convection oven (Model DHG070B, Shanghai Anting Scientific Instrument Factory, Shanghai, China) drying at 105 °C until a constant mass was reached [ 22 ]. One hundred grains were randomly selected to determine the dimensions of a single grain.…”