An evaluation of the relative ease of operation for cocurrent and countercurrent dryers

Models of cocurrent and countercurrent dryers have been developed within a process flowsheeting package (SPEEDUP(TM)) and applied to a case study of a timber veneer dryer to evaluate the balance between operating costs and the ease of control for these different contacting arrangements. For this case study, cocurrent working has been predicted to require only 2% more energy for the same final moisture content compared with countercurrent working. However, cocurrent working is significantly easier to control, according to several measures of process operability based on the steady-state response of the system.