Application of microwave low temperature drying equipment in pharmaceutical industry

Microwave vacuum drying equipment is a new type of microwave energy application equipment which combines microwave energy technology with vacuum technology. It has a series of advantages of microwave and vacuum drying. Flash dryer overcomes the disadvantages of conventional vacuum drying, such as long cycle and low efficiency. In the process of drying general materials, the efficiency can be increased by 4-10 times compared with the conventional method. With the advantages of high drying output, good quality and low processing cost, the microwave vacuum flash dryer is a high-tech product integrating electronics, vacuum, mechanics, thermodynamics, program control and other disciplines. It is based on the in-depth study of physical changes of substances, heat and mass exchange between inside and outside and water migration process under vacuum conditions, A new technology and process developed. In large-scale industrial production, there are many items that can not be dried under high temperature conditions, such as some drugs, chemicals, nutritious food, ginseng, pilose antler and other high-grade Chinese herbal medicines. In order to ensure the quality of the products, the drying treatment must be carried out at a temperature lower than 100 ℃ or at room temperature. It is well known that when the air pressure is lowered, the boiling point of water is also reduced, such as in an atmosphere The boiling point of water is 100 ℃ at 101.3kPa and 40 ℃ at 0.073 atmospheric pressure (7.37kpa). In the vacuum condition, heating the object can make the water inside the object evaporate without heating up. Because it is difficult to carry out air convection heat transfer under vacuum condition, it is necessary to rely on heat conduction to provide heat energy for materials. The conventional vacuum drying method is slow in heat transfer, low in efficiency and difficult in temperature control. Microwave heating is a kind of radiation heating, which is the direct interaction between microwave and material, so that it can be heated inside and outside at the same time, without convection or conduction to transfer heat. Therefore, the heating speed is fast, the drying efficiency is high, and the temperature control is easy.

In the 1980s, developed countries began to develop industrial microwave vacuum drying equipment, and achieved good results in practical application. French international microwave company uses microwave vacuum drying equipment to process seedless raisin. The traditional process of drying raisin by hot air at 65 ℃ for 24 hours is changed to microwave vacuum drying at 50 ℃ for 5 hours. The product quality and output are greatly improved. In the late 1990s, our company began to develop microwave vacuum equipment in China. Through several years' efforts, we completed the development of industrial 10kW microwave vacuum drying equipment in 2000. It provides a new and efficient drying equipment for pharmaceutical engineering, biological engineering, chemical engineering, material engineering and deep processing of agricultural and sideline products.

2、 Advantages of microwave vacuum drying equipment

1. High efficiency

Conventional vacuum drying equipment uses steam for heating, which needs heating from the inside to the outside. The heating speed is slow and a large amount of coal is consumed. However, the microwave vacuum drying equipment uses electromagnetic wave heating, without heat transfer medium, and directly heats to the inside of the object. The heating speed is fast. 1 kW microwave can heat water at room temperature to 100 ℃ in 3-5 minutes, which avoids the above shortcomings Therefore, the drying cycle is greatly shortened and the energy consumption is reduced. Compared with the conventional drying technology, the efficiency can be increased by more than four times.

2. Heat evenly

Due to the microwave heating, the material is heated from the inside to the outside at the same time. The temperature difference between the inside and outside of the material is very small, which will not lead to the inconsistency of the internal and external heating in the conventional heating, thus producing the expansion effect, which is conducive to crushing and greatly improving the drying quality.



3. Easy to control, convenient for continuous production and automation. Due to the characteristics of rapid adjustment of microwave power and no inertia, it is easy to control in real time. It can be arbitrarily controlled between 40 ℃ and 100 ℃. China Building Materials Network - building materials one point pass ranked the third among the peers

Five years together in the same boat

Adjust the temperature 4, spare volume small, easy to install and maintain

5. Compared with the conventional method, the quality of the processed product is greatly improved.

6. Microwave has the effect of disinfection and sterilization, and the product is safe and hygienic. Long shelf life.

7. The economic benefit is remarkable.

From the features introduced above, the remarkable economic and social benefits can be seen from the aspects of energy saving, consumption reduction, product quality improvement, safety and health, and low equipment investment cost.

3、 Basic structure and working principle

1. Flow chart of microwave vacuum drying equipment used in the processing of precious medicinal materials (omitted)

4、 Circuit control design

1. Block diagram of circuit composition (omitted)

5、 System design

1. Vacuum pump selection

2. Design of material turntable

3. Heat balance design of the whole machine

4. Power regulation design

6、 Economic benefit analysis

The technological performance, economic benefit and product quality of various drying equipment processed by a pharmaceutical factory in Jiangxi Province were compared

Project dynamic microwave drying spray drying flash dryer

The drying time is 45 ~ 70 minutes, 3 ~ 5 seconds, 20 ~ 45 hours

Drying temperature 45 ~ 60 degrees (arbitrary setting) air inlet 180 degrees 50 ~ 60 degrees (difficult to control)

The loss of extract is more than 0.2 ~ 5% 3%

Moisture 4 ~ 5% 2 ~ 4% 4 ~ 6%

Compared with other equipment, the content loss increases by 20-30% and decreases by 20-30%

Under the same production conditions, one set needs 3 sets and needs 5 sets

The cost per kilogram of dry ointment is 0.4 ~ 0.5 yuan / kg, 3 ~ 4 yuan / kg, 3 ~ 4 yuan / kg

Drying method: process configuration

The above can be seen: the drying cost is low, the efficiency is good, the equipment occupies a small area, which is equivalent to 20% of the area of the steam vacuum dryer, and 30% of the spray drying equipment saves the purification plant greatly. Dynamic vacuum microwave dryer is not only used for Chinese medicine extract, but also suitable for health care products, food and chemical products, especially for paste and viscous materials. It can also play a better role in killing bacteria.

7、 Conclusion

The successful development of industrial microwave vacuum drying equipment has filled the gap. This set of high-tech equipment has greatly promoted the development of national technology, especially the development of China's pharmaceutical industry, which will have a far-reaching impact. At the same time, its successful development has opened up a broader field for the application of microwave energy.

The successful development of the product has made breakthroughs in many key technologies, and some theoretical basis and methods of design have been put forward, and a lot of valuable experience has been obtained in practice, which has laid a solid foundation for the further development of this technology.

The actual operation shows that the equipment has excellent performance, advanced technology and reasonable design. It is a new technology and new product with remarkable economic benefit, good social benefit and high popularization value.