Drying equipment
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This post was last edited by beileim1 on 2009-6-23 at 20:12. Our company has a material that needs to be dried. This is a thermosensitive material with a melting point of around 38°C; it is also somewhat irritating. The material is obtained through centrifugation, with a moisture content of about 10%. The solvent used is isopropyl alcohol, and the particle size of the material is approximately 300 mesh. The annual production volume is around 2500 tons. What kind of drying equipment would be suitable for this material? It is best to be able to recycle the solvents produced, and try to prevent the materials from escaping. We have previously tried drying equipment such as twin-cone dryers and fluidized bed dryers; the twin-cone dryer tends to cause clumping during the drying process, while the fluidized bed dryer causes materials to melt, and in both cases the results were not good. Please offer some suggestions, experts. Thank you!
The melting point of this material is only 38 degrees Celsius, making it a thermosensitive material; moreover, the solvent contained within it needs to be recovered. In fact, when analyzing the principle of drying, it constitutes a chemical processing unit involving heat and mass transfer. Our usual drying process is aimed at increasing the mass transfer rate; to this end, a higher gas temperature is used to increase its unsaturation, thereby enabling evaporation-based mass transfer drying. It’s obvious that this approach won’t work in that case. Therefore, I suggest you consider two options: 1) Use freeze-drying, which is mainly suitable for heat-sensitive materials, taking advantage of the three-phase transition of water. However, it’s not clear whether this method can be applied to the specific material in question; a detailed analysis is needed, and moreover, the investment required is high ； 2. Use absolutely dry air for drying, employing mass transfer drying based on the unsaturation of the gas. Given that the moisture content there is low, and considering that it is an organic solvent with a high evaporation latent heat, this approach is worth trying. As for its specific structure, if the drying medium is changed, it can employ boiling drying, as well as methods such as air flow drying or drum drying.
Try vacuum vibration drying.
Spray drying is not very suitable. Spray drying is suitable for drying heat-sensitive materials, but the temperature of the material after drying is still around 50 degrees. If it is allowed for the material to melt and then solidify, a cooling system can be considered adding at the material collection point. Additionally, the melted liquid is carried away with the exhaust gases; cooling the exhaust gases is required to achieve separation, which results in higher energy consumption. Moreover, spraying is not suitable for recovering solvents.
1. Air drying is not feasible—the solvent cannot be recovered. 2. Indirect heating for drying is not suitable—due to the low melting point. 3. Freeze-drying equipment is expensive both in terms of purchase cost and operation costs, and it yields low production volumes. Microwave drying is recommended; Henan University of Science and Technology has a prototype available for testing
Microwave drying is more suitable; conventional air flow and spraying find it difficult to meet the requirements mentioned by the original poster.
A vacuum rotary low-temperature dryer with a capacity of 10 T/D can be used. Choose a few.
A vacuum mixing dryer can be used; the material is stirred by the rotation of the agitator both in a circular motion and in an axial direction inside the cylinder, which prevents caking. Drying speed is fast. Our company has prototypes available for testing. Contact number: 13912338893
The applicable temperature range is too low; only vacuum dryers can be used. Disk-type vacuum drying is recommended, as well as freeze-drying
Vacuum drying is necessary. Vacuum rake dryers, vacuum flash dryers, and vacuum paddle dryers are available for trial use.