Determination of orifice diameter for horizontal pipelines in layers for composing windrows via variation of pressure losses

Abstract

Compressed air plays an important role in forced aeration composting systems; the lateral outlet orifices on the main pipeline must be properly sized to maintain a pressure drop of less than 5% at the output of each orifice. Organic matter (OM) was aerated at a rate of 0.557 m3 air·d-1·kg-1, as determined by dry weight (DW), and the internal temperature and humidity of the windrows were monitored. The calculated variation of the pressure loss for the pipelines in the experimental windrow was between 1.53% and 2.56% at a maximum internal temperature of 70.8°C, unlike the conventional windrow, which reached a maximum temperature of 47.1°C. In both systems, the humidity was greater than 50%. The cost per metre for commercial scale implementation is equivalent to US$21.22, considering the use of alternative materials with the necessary mechanical and thermal resistance values.