The influence of crop dryer operation parameters on the efficiency of energy recovery from extract air

E Przydróżny ,Juliusz Walaszczyk,S Szczęśniak ,A Przydróżna

doi:10.1051/e3sconf/201911600064

Abstract

Crop drying, especially maize drying, occurs at low external air temperatures, which are lower than the extract air temperature. Therefore, using heat exchangers, to recover thermal energy from the extract air to preheat the cold and dry external air, results in a significant reduction in the primary energy demand for crop drying. The measurements of air parameters in the crop dryer, with a drying capacity of 19 Mg/h of maize, confirm the assumptions undertaken for the production of the heat recovery system. We apply the cross-counter-flow surface heat exchanger system to provide a significant improvement in the efficiency of crop drying. We perform the analysis of the thermal energy recovery system operation. Our results indicate the influence of the drying air set-point and the crop specific humidity on the efficiency of energy recovery from the exhaust air. We performed our measurements at different drying air temperature set-points and different crop relative humidity.

Highlights

Crop harvested from fields, especially maize, rarely has a relative humidity suitable for direct storage
We designed our measurements to assess the effect of grain humidity and drying air temperature on the efficiency € of energy recovery from the extract air for heating the drying air
This efficiency € is interpreted as the portion of thermal energy, obtained from the air removed from the dryer to preheat the drying air, relative to the total energy used to heat the air, determined from:

Summary

Introduction

Crop harvested from fields, especially maize, rarely has a relative humidity suitable for direct storage. Seeds harvested in autumn should usually be dried to the humidity appropriate for their storage. To dry the crop, the heated air with a low relative humidity is used. This airflow removes moisture as it washes the crop. Various technologies of drying air preparation can be selected; especially the method of air heating can vary. Obtaining energy for heating the drying air is often related to the possibility of using natural sources, e.g. solar energy [1]

Methods

Results

Conclusion