Energy and exergy analysis in an asphalt plant's rotary dryer Articles uri icon

publication date

  • May 2011

start page

  • 1039

end page

  • 1049

issue

  • 6-7

volume

  • 31

International Standard Serial Number (ISSN)

  • 1359-4311

Electronic International Standard Serial Number (EISSN)

  • 1873-5606

abstract

  • In this paper, energy and exergy analyses of a rotary dryer employed in a Hot Mix Asphalt (HMA) plant for heating and drying of the aggregates in the mixture is presented. In the analysis, the exergy method in addition to the more conventional energy analysis, is employed to identify and evaluate the ther modynamic losses. The results show that, at design conditions, the plant performs with energy and exergy efficiencies of 0.89 and 0.18, respectively. The energy losses are mainly due to the flue gases. The exergy distribution indicates that the combustion and the heat transfer at different temperatures in the burner yield the highest exergy destruction in the process. A parametric study is conducted for the plant under various operational production parameters, including different humidities of the aggregates and filler content in aggregates, working temperatures and ambient conditions, in order to determine the parameters that affect the plant performance. It is shown that the solids humidity has a great impact on energy requirements. A better and sustainable use of the heat source employed in the dryer is proposed to avoid the high irreversibilities found. Furthermore, operating corrections in the mix or in the exhaust gas temperature are proposed to optimize the performance of the plant

keywords

  • exergy; exergy analysis; asphalt plant; drying; rotary dryer