Effect of radio frequency (RF) drying technology on dehydration rate and energy consumption of Australia lignite

Abstract

ABSTRACTIn order to obtain the optimum operating parameters for drying Australia lignite with radio frequency (RF) technology, a four-factor central composite design was adopted to investigate the effects of electrode gap (d), sample mass (m), intermittency (α), and total drying time (t) on dehydration rate (DR) and energy consumption (W). The results indicated that the dehydration rate and energy consumption were significantly (p < 0.01) affected by the processing factors, such as electrode gap, sample mass, intermittency, and total drying time. The variations could be well described by quadratic polynomial models. The fitting degree and confidence of regression equations were high, and the optimum operating conditions could be well predicted by the regression model. The optimum operating parameters for drying Australia lignite with RF were electrode gap of 35 mm, sample mass of 478 g, intermittency of 0.8, and total drying time of 28 min. According to the operating parameters, the obtained dehydration rate and energy consumption were 91.58% and 3.38 kW · h/kg, respectively. The experimental results showed that the proposed method could obtain the optimum operating conditions for drying Australia lignite with RF heating.