A flowsheet model of a well-mixed fluidized bed dryer: Applications in controllability assessment and optimization

A model of a well-mixed fluidized-bed dryer within a process flowsheeting p ackage (SPEEDUP(TM)) has been developed and applied to a parameter sensitiv ity study, a steady-state controllability analysis and an optimization stud y. This approach is more general and would be more easily applied to a comp lex flowsheet than one which relied on stand-alone dryer modelling packages . The simulation has shown that industrial data may be fitted to the model outputs with sensible values of unknown parameters. For this case study, th e parameter sensitivity study has found that the heat loss from the dryer a nd the critical moisture content of the material have the greatest impact o n the dryer operation at the current operating point. An optimization study has demonstrated the dominant effect of the heat loss from the dryer on th e current operating cost and the current operating conditions, and substant ial cost savings (around 50%) could be achieved with a well-insulated and a irtight dryer, for the specific case studied here.