The purpose of the qualification study (or studies) is to demonstrate that the equipment is fit for purpose. This shows that it is correctly installed and that it functions correctly and as you expect it to.
They may also help you write good procedures for using the equipment. (As an example, if the start button is a large green push-button, and your procedure says that to start the equipment you depress the yellow lever, your operators may have a problem).
The process validation demonstrates that when the equipment is in its normal production environment, it makes “good” product. So it should look at the equipment, the people operating it and the procedures they follow when operating it, and doing any product testing etc.
Both stages are necessary and will be requested in audits.
However, for simple equipment, none of the stages should take long, or be very difficult.
I disagree that when the equipment is validated you can dry any product in it. Once the equipment is qualified, then you may dry any product in it. But different products will dry quite differently – a sticky, aggregated product will probably take longer than a free-flowing crystalline type one. Drying time will be one element which you could have to prove on a product-by-product basis as part of your process validation stage.
I hope this helps.