Problems with vacuum drying of twin cones
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The materials produced by the company are dried using twin-cone vacuum dryers, with the moisture content required to be below 0.1; the melting point of these materials is 63.5 degrees. Hot water circulation is used for heating, with a water temperature of 52 degrees and a vacuum level of -0.08. The moisture level always stays around 0.2; sometimes it even increases. What’s going on? The vacuum pipeline has been cleaned using steam, and the filter cloth inside the dryer has also been replaced. I seek advice. . . .
How is moisture measured? Boiling drying or crushing followed by drying could be considered.
The humidity of the surrounding air is too high. Reduce the air humidity around the biconic shape
This post was last edited by Deep Sea Octopus on 2016-8-26 at 11:22. The low vacuum level, combined with the low temperature of the circulating water, makes it very difficult to remove moisture later on； I’m not sure what the properties of your material are; if it clumps together during drying, it will be difficult to dry ； After drying, nitrogen needs to be introduced to evacuate the air and prevent re-absorption of moisture.
Our materials are first crushed and then dried; the vacuum pressure of the twin-cone vacuum dryer is --0.98
Does the temperature rising as baking progresses indicate a change in the properties of the material? It shouldn’t be due to air humidity; if it were caused by air humidity, then how could it be packaged? We have encountered similar problems before, where the moisture level increased as drying progressed, and it was eventually determined that it was a problem with the material itself.
The vacuum level is not sufficient; nitrogen protection is required
What was the humidity level before drying? High humidity leads to caking and makes drying difficult
It seems that the problem might be caused by the interaction between other solvents and water; perhaps it would be advisable to increase the temperature of the circulating water a bit, or to reduce the vacuum level and open the sampling port (in an environment with high humidity) in order to carry out a drying process!