Drying Question

[ubcomposites]

If I have a material that needs to be dried and the quantity I am looking at is much to large to test, I must use a smaller sample and interpolate. I am looking to dry a material and the time allotted for this process is limited by space and production rate. If I need to dry say 500 lbs. of a material in 4 minutes and 40 seconds, but I can only test 100 – 500 grams of the material in a laboratory oven, how would I determine the temperature needed to dry 500 lbs within the 4min and 40secs. I can test out 100-500 gram samples and vary the temperature used and get the time taken to completely dry it at each respective temperature and mass. I am just unsure how to take this data and use it to interpolate to my need mass and time.

 

[Montemayor]

ubcomposites:

I don't know if you have process experience - specifically in designing or operating industrial dryers, of all types. However, some of the important parameters in considering when selecting a dryer type of method is determination of the thermal resistance properties of your material to be dried. If your material is a sensitive organic, you may run into difficulties in applying a temperature that is too hot. Some materials may actually catch on fire if heated too fast or too hot. You are correct in bench testing your material for these basic characteristics before applying a dryer.

The type of dryer is important also. Flash drying is one unit operation that is employed where large quantities of water are involved and time is short. Hot flue gases are often used as the heat media. I believe you should select the maximum temperature your material can tolerate, the type of heat media to be used, and the type of dryer that is best or suits your requirements. That is normally the steps taken in selecting a drying process.

 

[HEC]

ubcomposites:

The lab scale trials will give an indication of drying rates, as Montemayor has said it is an important step in determination of basic material drying properties.

To determine the best drying process or combination of processes the material properties must be looked at. What type of material are you trying to dry, is it granular, fiberous, solid, etc. What is the starting water or moisture content? What is the final moisture content required? From these the style of dryer can be determined and then an estimate of processing rates can be made.

If you can describe the material to be dried, the start and finish moisture content more guidence can be given.

Regards
hutton4eng@picknowl.com.au

Mark Hutton

 

[chicopee]

Assuming that you have a convection drying oven,you can time several pilot tests for different wts, temp conditions and air flows, plot your results and extrapolate estimates for the loads you want to dry.