Batch distillation and continuous distillation in terms of production equipment, operating methods, energy consumption, as well as in the labor intensity and product quality are very different.
First of all, the production equipment is different, the continuous distillation method is carried out in the distillation tower, the equipment is more complex, the investment is large, and the intermittent distillation method is carried out in the distillation pot, the equipment is simpler, the investment is small. Continuous distillation from the fat liquid into the preheater to the bottom of the tower to release rosin, generally 10 to 20 minutes, and batch distillation heating time up to 40 to 50 minutes. Due to the short heating time of continuous distillation, the discoloration and degradation of rosin is less, and the quality of rosin products can be maintained at the level before rosin processing, while intermittent distillation products are reduced by half to one level compared with continuous distillation products.
Secondly, the operation method is different. Continuous distillation is that the distilled rosin is continuously fed into the distillation tower and flows down the overflow pipe. Volatile turpentine is continuously heated and vaporized to rise. Excellent oil, medium oil and heavy oil with different boiling points can be drawn out at different positions of the tower, while difficult volatile rosin is continuously released from the bottom of the tower. The characteristic of continuous distillation is that when the feed composition is unchanged and the operation is stable, the composition of the distillate, distillate and bottom discharge on the tower plate does not change with time. This distillation method has high yield, stable quality, simplified operation and is convenient for automatic production. Intermittent distillation is to add turpentine into distillation pot in batches, so that volatile turpentine oil is heated and gradually vaporized. According to the change of liquid or vapor phase temperature, excellent oil, medium oil and heavy oil with different boiling points are collected. Difficult volatile rosin is regularly released from the distillation pot. Batch distillation is characterized by changes in the composition of the distillate and distillate over time. This distillation method, the equipment is simple, easy to master, but the operator often according to the material composition and temperature changes to adjust the steam pressure, the operation is cumbersome, the product quality is not stable enough.
Once again, the continuous distillation efficiency is high, which can save steam energy. Continuous distillation saves open steam by nearly 60% over batch distillation.
In particular, it should be pointed out that the continuous distillation process requires high conditions. If the operation is careless, it will affect the product quality produced for a period of time, while intermittent distillation, in case of careless operation, only affects the product quality of the pan.