Process Validation or Qualification?


I am working for an API manufacturing plant.

In case of producing one batch of certain API, we decide to use two dryers (actually have same standard of dryer) becasue of insufficient capacity.

To prove its same high quality of products (compare with quality of products while using just one dryer), we perform ‘Qualification of dryers’

and we have plan to do ‘Process Validation’.

Is there are any references including as stated above (e.g. ICH, WHO, PICs Guideline).

I want to know if it is possible or reasonable to use two dryers during one manufacturing process.

I would appreciate if someone helps me.