Research and development and application of spray drying machine for Chinese medicine extract

Overview

The chemical properties of Chinese medicine are complex and diverse. We systematically analyze its properties and design a more reasonable ZGP series Chinese medicine extract spray dryer to address the existing problems. It has a good adaptability to materials with low softening points and strong hygroscopicity. Compared with ordinary centrifugal spray, ZPG creatively adds a purge device, a cold air jacket device and a mist pressure device, which greatly improves the efficiency. At the same time, it fully complies with GMP regulations and designs the equipment more reasonably, scientifically, environmentally friendly and hygienic.

Chinese herbal medicines are extracted, concentrated and dried to make various granules, tablets, capsules and pills to meet the needs of different groups of people.

1. Chinese medicine extraction and processing process:

                                           Chinese medicine processing process flow chart

2.In order to increase the yield of active ingredients and make full use of medicinal resources, the extraction process usually uses a solvent that is 6-10 times the amount of medicinal materials, so that the concentration of the obtained extract is very small, with a solid content of about 2%. Therefore, it is necessary to add a concentration and drying step to compress the extract and remove the solvent.

3. The drying problem of Chinese medicine extract is the key to the entire process. The quality of drying will have a significant impact on product quality. In the previous drying process, ovens and vacuum drying were used. Due to the long drying time, the effective ingredients were damaged to a certain extent, and they had to be crushed after drying, which resulted in serious waste. LPG spray dryers are used, but they are not suitable for drying multiple varieties of Chinese medicine extracts and most materials. The main problem is that the material sticks to the wall during the drying process, and after the material sticks to the wall, it will melt and coke after a long period of high temperature. The effective ingredients are severely damaged and difficult to clean, and cannot meet GMP standards.

In the LPG centrifugal spray process, the wall sticking phenomenon is divided into three types

1、When the atomized droplets reach the cylinder wall, the material is not completely dry, so semi-dry material adheres to the cylinder wall.

Problem Analysis: The semi-dry material sticks to the wall when the droplets sprayed directly from the atomizer fly onto the cylinder wall. When there are coarse particles in the material mist or the atomization is incomplete, this phenomenon of sticking to the wall will occur. Therefore, the atomizer must be operated correctly. In addition, due to the unreasonable design of the hot air distributor, the semi-dry material will also partially stick to the wall.

2、Because of the temperature inside the drying chamber, the material becomes viscous.

Problem Analysis: When the viscous material reaches a certain thickness, it will automatically fall off, leaving a clean wall surface.

3、The dry powder adheres to the cylinder wall.

Problem analysis: When the dry material inevitably comes into contact with the wall, the adsorption phenomenon that occurs is mostly related to the cleanliness of the wall, the local air flow rate, and the electrostatic attraction between the material and the cylinder wall.

Most Chinese herbal medicines contain polysaccharides with low melting points. During the drying process, they will melt and be adsorbed on the cylinder wall. In order to avoid the above three phenomena, engineers added a mist pressure device and an air purge device to avoid long-term contact between the material and the cylinder wall as much as possible.

The residual moisture of Chinese herbal extract powder is required to be less than 5%. Considering that there are other process links from spray drying to preparation, in these links, Chinese herbal extract powder will also absorb moisture, which will increase the residual moisture. Therefore, in the drying process, the residual moisture needs to be controlled at 3% to 4%. This requires the outlet air temperature of the drying tower to reach 85-95℃. This makes the temperature of the receiving barrel below the cyclone separator too high, and the dried product melts and agglomerates. In order to solve this problem, engineers installed air dehumidification and cooling devices under the cyclone separator. The purpose is to quickly transfer the material from the high temperature area and send it to the receiving cyclone set in the purification area. Carry out subsequent processes.

There are many varieties of Chinese medicinal materials, and the extraction components are complex. The characteristics of the extracted concentrates vary greatly, especially for polysaccharide extracts with low softening points and strong hygroscopicity. The industry has combined past experience with the latest scientific research results to develop a new generation of ZPG Chinese medicine extract spray dryer. The volume of this dryer is more than twice that of the traditional LPG dryer. It has a cold wall device and a rotary air sweeping device to ensure that the material does not stick to the wall or coke. The entire equipment uses a CIP cleaning device, which is suitable for the drying requirements of multiple varieties. The air intake adopts three-effect filtration to make the air intake meet the purification requirements of 100,000 levels. The air outlet adopts water foam dust removal, which will not pollute the environment and also improve the powder collection rate.

ZPG Chinese medicine extract spray dryer has the advantages of fast speed, high efficiency, and fewer processes. It can maintain the color, aroma and taste of heat-sensitive materials. The dry powder has good solubility, high purity and good spraying effect. It solves the problem of spraying powder sticking to the wall and coking, and greatly improves the powder collection rate. It has become the preferred drying equipment for Chinese medicine extract.

                                                             LPG centrifugal spray dryer

                             ZPG Chinese medicine extract spray drying machine

ZPG spray dryer is different from LPG spray dryer in that

1、A rotating air sweep device was added inside the main tower;

2、A cold air jacket is added between the main tower insulation layer and the inner tube wall;

3、Added a dehumidification air cooling device for the main cyclone unloading;

4、Added centralized material collection cyclone;

5、Added atomizer air pressure device;

6、Comply with GMP standards;

Working Principle

After the air is filtered and heated at the primary, secondary and high levels, it enters the air distributor at the top of the dryer in a spiral tangent manner, and the hot air enters the drying chamber in a spiral shape and uniformly. At the same time, the liquid is atomized into 20-60μm droplets by the atomizer. When the droplets are in co-current contact with the hot air, they can be dried into powder products in a very short time. The dried powder is continuously output from the bottom of the drying tower and the cyclone separator. A small part of the powder enters the water foam dust removal spray and the exhaust gas is discharged by the induced draft fan.

Characteristics of ZPG spray dryer

1、Fast drying speed. After the liquid is atomized by the atomizer, the surface area is greatly increased, and 95%-98% of the water can be evaporated instantly in the high-temperature airflow, and the drying time is only a few seconds.

2、After the liquid material enters the spray tower, it immediately contacts with the hot air, the temperature inside the drying tower drops, and the material will not be overheated, which is suitable for heat-sensitive materials.

3、The dried product is uniform, loose, non-sticky, and has good fluidity, looseness and solubility, making it easy to package dosages and dissolve for use.

4、The equipment is equipped with air wall sweeping and tower wall jacket cooling structure, which can effectively prevent the product from sticking to the wall and coking, and improve product quality and yield.

5、The equipment has a simple structure, is easy to operate and maintain, and users can choose the appropriate equipment model according to the material characteristics to achieve the best adaptability.

6、The Chinese medicine extract spray dryer can dry various Chinese medicine extracts, plant extracts, chemical medicine extracts and other liquid materials, and has a wide range of applications. :

7、The spray dryer can be equipped with a unique finished product air delivery system, which can separate the dried finished product from the hot and humid air in the system in time to avoid the possibility of moisture absorption, rehumidification and agglomeration of the finished product.

8、The air entering the dryer may be subjected to three-stage air purification to ensure that the incoming air meets certain quality standards.

9、The design and production of the entire drying system may comply with GMP standards to ensure the hygiene and quality of pharmaceutical production.

Drying process of Chinese medicine extract spray dryer

ZPG renderings

GMP of ZPG drying equipment

The main GMP functions in drying equipment are: purification function, cleaning function, detection and control function.

1、Purification function: In drying equipment, gas pollution is the most obvious.

In order to prevent the product from being contaminated by this type of pollution, the air that comes into contact with the product must be filtered, that is, the air enters the equipment after going through three levels of purification: primary, secondary and high.

2、Cleaning function: All GMPs advocate online cleaning, i.e. CIP

The CIP cleaning system consists of a hot water tank, an alkaline water tank, a pure water tank, a cleaning water pump, a water distributor, a pressure cleaning head, valves, pipes and a control system. The entire set of equipment can be automated and thoroughly cleaned without dead ends.

                                CIP cleaning pipeline at a construction site

     A construction site receiving cyclone CIP cleaning pipeline

3、Detection and control function: This function mainly refers to the equipment has analysis

The processing system can automatically complete one or more processes. At present, there is still a lot of room for improvement in the extract spray control system on the market. There is still a long way to go to achieve one-button start and full automation of the equipment. This is also an important task for us in the future.

Some pictures of the construction site